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cam_xpt.c

/*-
 * Implementation of the Common Access Method Transport (XPT) layer.
 *
 * Copyright (c) 1997, 1998, 1999 Justin T. Gibbs.
 * Copyright (c) 1997, 1998, 1999 Kenneth D. Merry.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification, immediately at the beginning of the file.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/cam/cam_xpt.c,v 1.155.2.11 2007/03/08 05:30:26 mjacob Exp $");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/systm.h>
#include <sys/types.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/time.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/md5.h>
#include <sys/interrupt.h>
#include <sys/sbuf.h>

#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sysctl.h>
#include <sys/kthread.h>

#ifdef PC98
#include <pc98/pc98/pc98_machdep.h> /* geometry translation */
#endif

#include <cam/cam.h>
#include <cam/cam_ccb.h>
#include <cam/cam_periph.h>
#include <cam/cam_sim.h>
#include <cam/cam_xpt.h>
#include <cam/cam_xpt_sim.h>
#include <cam/cam_xpt_periph.h>
#include <cam/cam_debug.h>

#include <cam/scsi/scsi_all.h>
#include <cam/scsi/scsi_message.h>
#include <cam/scsi/scsi_pass.h>
#include <machine/stdarg.h>   /* for xpt_print below */
#include "opt_cam.h"

/* Datastructures internal to the xpt layer */
MALLOC_DEFINE(M_CAMXPT, "CAM XPT", "CAM XPT buffers");

/*
 * Definition of an async handler callback block.  These are used to add
 * SIMs and peripherals to the async callback lists.
 */
struct async_node {
      SLIST_ENTRY(async_node) links;
      u_int32_t   event_enable;     /* Async Event enables */
      void        (*callback)(void *arg, u_int32_t code,
                            struct cam_path *path, void *args);
      void        *callback_arg;
};

SLIST_HEAD(async_list, async_node);
SLIST_HEAD(periph_list, cam_periph);
static STAILQ_HEAD(highpowerlist, ccb_hdr) highpowerq;

/*
 * This is the maximum number of high powered commands (e.g. start unit)
 * that can be outstanding at a particular time.
 */
#ifndef CAM_MAX_HIGHPOWER
#define CAM_MAX_HIGHPOWER  4
#endif

/* number of high powered commands that can go through right now */
static int num_highpower = CAM_MAX_HIGHPOWER;

/*
 * Structure for queueing a device in a run queue.
 * There is one run queue for allocating new ccbs,
 * and another for sending ccbs to the controller.
 */
struct cam_ed_qinfo {
      cam_pinfo pinfo;
      struct        cam_ed *device;
};

/*
 * The CAM EDT (Existing Device Table) contains the device information for
 * all devices for all busses in the system.  The table contains a
 * cam_ed structure for each device on the bus.
 */
struct cam_ed {
      TAILQ_ENTRY(cam_ed) links;
      struct      cam_ed_qinfo alloc_ccb_entry;
      struct      cam_ed_qinfo send_ccb_entry;
      struct      cam_et       *target;
      lun_id_t     lun_id;
      struct      camq drvq;        /*
                               * Queue of type drivers wanting to do
                               * work on this device.
                               */
      struct      cam_ccbq ccbq;          /* Queue of pending ccbs */
      struct      async_list asyncs;      /* Async callback info for this B/T/L */
      struct      periph_list periphs;    /* All attached devices */
      u_int generation;       /* Generation number */
      struct      cam_periph *owner;      /* Peripheral driver's ownership tag */
      struct      xpt_quirk_entry *quirk; /* Oddities about this device */
                              /* Storage for the inquiry data */
#ifdef CAM_NEW_TRAN_CODE
      cam_proto    protocol;
      u_int        protocol_version;
      cam_xport    transport;
      u_int        transport_version;
#endif /* CAM_NEW_TRAN_CODE */
      struct             scsi_inquiry_data inq_data;
      u_int8_t     inq_flags; /*
                               * Current settings for inquiry flags.
                               * This allows us to override settings
                               * like disconnection and tagged
                               * queuing for a device.
                               */
      u_int8_t     queue_flags;     /* Queue flags from the control page */
      u_int8_t     serial_num_len;
      u_int8_t    *serial_num;
      u_int32_t    qfrozen_cnt;
      u_int32_t    flags;
#define CAM_DEV_UNCONFIGURED        0x01
#define CAM_DEV_REL_TIMEOUT_PENDING 0x02
#define CAM_DEV_REL_ON_COMPLETE           0x04
#define CAM_DEV_REL_ON_QUEUE_EMPTY  0x08
#define CAM_DEV_RESIZE_QUEUE_NEEDED 0x10
#define CAM_DEV_TAG_AFTER_COUNT           0x20
#define CAM_DEV_INQUIRY_DATA_VALID  0x40
      u_int32_t    tag_delay_count;
#define     CAM_TAG_DELAY_COUNT           5
      u_int32_t    tag_saved_openings;
      u_int32_t    refcount;
      struct             callout_handle c_handle;
};

/*
 * Each target is represented by an ET (Existing Target).  These
 * entries are created when a target is successfully probed with an
 * identify, and removed when a device fails to respond after a number
 * of retries, or a bus rescan finds the device missing.
 */
struct cam_et { 
      TAILQ_HEAD(, cam_ed) ed_entries;
      TAILQ_ENTRY(cam_et) links;
      struct      cam_eb      *bus; 
      target_id_t target_id;
      u_int32_t   refcount;   
      u_int       generation;
      struct            timeval last_reset;
};

/*
 * Each bus is represented by an EB (Existing Bus).  These entries
 * are created by calls to xpt_bus_register and deleted by calls to
 * xpt_bus_deregister.
 */
struct cam_eb { 
      TAILQ_HEAD(, cam_et) et_entries;
      TAILQ_ENTRY(cam_eb)  links;
      path_id_t        path_id;
      struct cam_sim         *sim;
      struct timeval         last_reset;
      u_int32_t        flags;
#define     CAM_EB_RUNQ_SCHEDULED   0x01
      u_int32_t        refcount;
      u_int            generation;
};

struct cam_path {
      struct cam_periph *periph;
      struct cam_eb       *bus;
      struct cam_et       *target;
      struct cam_ed       *device;
};

struct xpt_quirk_entry {
      struct scsi_inquiry_pattern inq_pat;
      u_int8_t quirks;
#define     CAM_QUIRK_NOLUNS  0x01
#define     CAM_QUIRK_NOSERIAL      0x02
#define     CAM_QUIRK_HILUNS  0x04
#define     CAM_QUIRK_NOHILUNS      0x08
      u_int mintags;
      u_int maxtags;
};

static int cam_srch_hi = 0;
TUNABLE_INT("kern.cam.cam_srch_hi", &cam_srch_hi);
static int sysctl_cam_search_luns(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_kern_cam, OID_AUTO, cam_srch_hi, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
    sysctl_cam_search_luns, "I",
    "allow search above LUN 7 for SCSI3 and greater devices");

#define     CAM_SCSI2_MAXLUN  8
/*
 * If we're not quirked to search <= the first 8 luns
 * and we are either quirked to search above lun 8,
 * or we're > SCSI-2 and we've enabled hilun searching,
 * or we're > SCSI-2 and the last lun was a success,
 * we can look for luns above lun 8.
 */
#define     CAN_SRCH_HI_SPARSE(dv)                    \
  (((dv->quirk->quirks & CAM_QUIRK_NOHILUNS) == 0)    \
  && ((dv->quirk->quirks & CAM_QUIRK_HILUNS)          \
  || (SID_ANSI_REV(&dv->inq_data) > SCSI_REV_2 && cam_srch_hi)))

#define     CAN_SRCH_HI_DENSE(dv)                     \
  (((dv->quirk->quirks & CAM_QUIRK_NOHILUNS) == 0)    \
  && ((dv->quirk->quirks & CAM_QUIRK_HILUNS)          \
  || (SID_ANSI_REV(&dv->inq_data) > SCSI_REV_2)))

typedef enum {
      XPT_FLAG_OPEN           = 0x01
} xpt_flags;

struct xpt_softc {
      xpt_flags   flags;
      u_int32_t   generation;
};

static const char quantum[] = "QUANTUM";
static const char sony[] = "SONY";
static const char west_digital[] = "WDIGTL";
static const char samsung[] = "SAMSUNG";
static const char seagate[] = "SEAGATE";
static const char microp[] = "MICROP";

static struct xpt_quirk_entry xpt_quirk_table[] = 
{
      {
            /* Reports QUEUE FULL for temporary resource shortages */
            { T_DIRECT, SIP_MEDIA_FIXED, quantum, "XP39100*", "*" },
            /*quirks*/0, /*mintags*/24, /*maxtags*/32
      },
      {
            /* Reports QUEUE FULL for temporary resource shortages */
            { T_DIRECT, SIP_MEDIA_FIXED, quantum, "XP34550*", "*" },
            /*quirks*/0, /*mintags*/24, /*maxtags*/32
      },
      {
            /* Reports QUEUE FULL for temporary resource shortages */
            { T_DIRECT, SIP_MEDIA_FIXED, quantum, "XP32275*", "*" },
            /*quirks*/0, /*mintags*/24, /*maxtags*/32
      },
      {
            /* Broken tagged queuing drive */
            { T_DIRECT, SIP_MEDIA_FIXED, microp, "4421-07*", "*" },
            /*quirks*/0, /*mintags*/0, /*maxtags*/0
      },
      {
            /* Broken tagged queuing drive */
            { T_DIRECT, SIP_MEDIA_FIXED, "HP", "C372*", "*" },
            /*quirks*/0, /*mintags*/0, /*maxtags*/0
      },
      {
            /* Broken tagged queuing drive */
            { T_DIRECT, SIP_MEDIA_FIXED, microp, "3391*", "x43h" },
            /*quirks*/0, /*mintags*/0, /*maxtags*/0
      },
      {
            /*
             * Unfortunately, the Quantum Atlas III has the same
             * problem as the Atlas II drives above.
             * Reported by: "Johan Granlund" <johan@granlund.nu>
             *
             * For future reference, the drive with the problem was:
             * QUANTUM QM39100TD-SW N1B0
             * 
             * It's possible that Quantum will fix the problem in later
             * firmware revisions.  If that happens, the quirk entry
             * will need to be made specific to the firmware revisions
             * with the problem.
             * 
             */
            /* Reports QUEUE FULL for temporary resource shortages */
            { T_DIRECT, SIP_MEDIA_FIXED, quantum, "QM39100*", "*" },
            /*quirks*/0, /*mintags*/24, /*maxtags*/32
      },
      {
            /*
             * 18 Gig Atlas III, same problem as the 9G version.
             * Reported by: Andre Albsmeier
             *          <andre.albsmeier@mchp.siemens.de>
             *
             * For future reference, the drive with the problem was:
             * QUANTUM QM318000TD-S N491
             */
            /* Reports QUEUE FULL for temporary resource shortages */
            { T_DIRECT, SIP_MEDIA_FIXED, quantum, "QM318000*", "*" },
            /*quirks*/0, /*mintags*/24, /*maxtags*/32
      },
      {
            /*
             * Broken tagged queuing drive
             * Reported by: Bret Ford <bford@uop.cs.uop.edu>
             *         and: Martin Renters <martin@tdc.on.ca>
             */
            { T_DIRECT, SIP_MEDIA_FIXED, seagate, "ST410800*", "71*" },
            /*quirks*/0, /*mintags*/0, /*maxtags*/0
      },
            /*
             * The Seagate Medalist Pro drives have very poor write
             * performance with anything more than 2 tags.
             * 
             * Reported by:  Paul van der Zwan <paulz@trantor.xs4all.nl>
             * Drive:  <SEAGATE ST36530N 1444>
             *
             * Reported by:  Jeremy Lea <reg@shale.csir.co.za>
             * Drive:  <SEAGATE ST34520W 1281>
             *
             * No one has actually reported that the 9G version
             * (ST39140*) of the Medalist Pro has the same problem, but
             * we're assuming that it does because the 4G and 6.5G
             * versions of the drive are broken.
             */
      {
            { T_DIRECT, SIP_MEDIA_FIXED, seagate, "ST34520*", "*"},
            /*quirks*/0, /*mintags*/2, /*maxtags*/2
      },
      {
            { T_DIRECT, SIP_MEDIA_FIXED, seagate, "ST36530*", "*"},
            /*quirks*/0, /*mintags*/2, /*maxtags*/2
      },
      {
            { T_DIRECT, SIP_MEDIA_FIXED, seagate, "ST39140*", "*"},
            /*quirks*/0, /*mintags*/2, /*maxtags*/2
      },
      {
            /*
             * Slow when tagged queueing is enabled.  Write performance
             * steadily drops off with more and more concurrent
             * transactions.  Best sequential write performance with
             * tagged queueing turned off and write caching turned on.
             *
             * PR:  kern/10398
             * Submitted by:  Hideaki Okada <hokada@isl.melco.co.jp>
             * Drive:  DCAS-34330 w/ "S65A" firmware.
             *
             * The drive with the problem had the "S65A" firmware
             * revision, and has also been reported (by Stephen J.
             * Roznowski <sjr@home.net>) for a drive with the "S61A"
             * firmware revision.
             *
             * Although no one has reported problems with the 2 gig
             * version of the DCAS drive, the assumption is that it
             * has the same problems as the 4 gig version.  Therefore
             * this quirk entries disables tagged queueing for all
             * DCAS drives.
             */
            { T_DIRECT, SIP_MEDIA_FIXED, "IBM", "DCAS*", "*" },
            /*quirks*/0, /*mintags*/0, /*maxtags*/0
      },
      {
            /* Broken tagged queuing drive */
            { T_DIRECT, SIP_MEDIA_REMOVABLE, "iomega", "jaz*", "*" },
            /*quirks*/0, /*mintags*/0, /*maxtags*/0
      },
      {
            /* Broken tagged queuing drive */ 
            { T_DIRECT, SIP_MEDIA_FIXED, "CONNER", "CFP2107*", "*" },
            /*quirks*/0, /*mintags*/0, /*maxtags*/0
      },
      {
            /* Does not support other than LUN 0 */
            { T_DIRECT, SIP_MEDIA_FIXED, "VMware*", "*", "*" },
            CAM_QUIRK_NOLUNS, /*mintags*/2, /*maxtags*/255
      },
      {
            /*
             * Broken tagged queuing drive.
             * Submitted by:
             * NAKAJI Hiroyuki <nakaji@zeisei.dpri.kyoto-u.ac.jp>
             * in PR kern/9535
             */
            { T_DIRECT, SIP_MEDIA_FIXED, samsung, "WN34324U*", "*" },
            /*quirks*/0, /*mintags*/0, /*maxtags*/0
      },
        {
            /*
             * Slow when tagged queueing is enabled. (1.5MB/sec versus
             * 8MB/sec.)
             * Submitted by: Andrew Gallatin <gallatin@cs.duke.edu>
             * Best performance with these drives is achieved with
             * tagged queueing turned off, and write caching turned on.
             */
            { T_DIRECT, SIP_MEDIA_FIXED, west_digital, "WDE*", "*" },
            /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
            /*
             * Slow when tagged queueing is enabled. (1.5MB/sec versus
             * 8MB/sec.)
             * Submitted by: Andrew Gallatin <gallatin@cs.duke.edu>
             * Best performance with these drives is achieved with
             * tagged queueing turned off, and write caching turned on.
             */
            { T_DIRECT, SIP_MEDIA_FIXED, west_digital, "ENTERPRISE", "*" },
            /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
      {
            /*
             * Doesn't handle queue full condition correctly,
             * so we need to limit maxtags to what the device
             * can handle instead of determining this automatically.
             */
            { T_DIRECT, SIP_MEDIA_FIXED, samsung, "WN321010S*", "*" },
            /*quirks*/0, /*mintags*/2, /*maxtags*/32
      },
      {
            /* Really only one LUN */
            { T_ENCLOSURE, SIP_MEDIA_FIXED, "SUN", "SENA", "*" },
            CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
      },
      {
            /* I can't believe we need a quirk for DPT volumes. */
            { T_ANY, SIP_MEDIA_FIXED|SIP_MEDIA_REMOVABLE, "DPT", "*", "*" },
            CAM_QUIRK_NOSERIAL|CAM_QUIRK_NOLUNS,
            /*mintags*/0, /*maxtags*/255
      },
      {
            /*
             * Many Sony CDROM drives don't like multi-LUN probing.
             */
            { T_CDROM, SIP_MEDIA_REMOVABLE, sony, "CD-ROM CDU*", "*" },
            CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
      },
      {
            /*
             * This drive doesn't like multiple LUN probing.
             * Submitted by:  Parag Patel <parag@cgt.com>
             */
            { T_WORM, SIP_MEDIA_REMOVABLE, sony, "CD-R   CDU9*", "*" },
            CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
      },
      {
            { T_WORM, SIP_MEDIA_REMOVABLE, "YAMAHA", "CDR100*", "*" },
            CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
      },
      {
            /*
             * The 8200 doesn't like multi-lun probing, and probably
             * don't like serial number requests either.
             */
            {
                  T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "EXABYTE",
                  "EXB-8200*", "*"
            },
            CAM_QUIRK_NOSERIAL|CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
      },
      {
            /*
             * Let's try the same as above, but for a drive that says
             * it's an IPL-6860 but is actually an EXB 8200.
             */
            {
                  T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "EXABYTE",
                  "IPL-6860*", "*"
            },
            CAM_QUIRK_NOSERIAL|CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
      },
      {
            /*
             * These Hitachi drives don't like multi-lun probing.
             * The PR submitter has a DK319H, but says that the Linux
             * kernel has a similar work-around for the DK312 and DK314,
             * so all DK31* drives are quirked here.
             * PR:            misc/18793
             * Submitted by:  Paul Haddad <paul@pth.com>
             */
            { T_DIRECT, SIP_MEDIA_FIXED, "HITACHI", "DK31*", "*" },
            CAM_QUIRK_NOLUNS, /*mintags*/2, /*maxtags*/255
      },
      {
            /*
             * The Hitachi CJ series with J8A8 firmware apparantly has
             * problems with tagged commands.
             * PR: 23536
             * Reported by: amagai@nue.org
             */
            { T_DIRECT, SIP_MEDIA_FIXED, "HITACHI", "DK32CJ*", "J8A8" },
            CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
      },
      {
            /*
             * These are the large storage arrays.
             * Submitted by:  William Carrel <william.carrel@infospace.com>
             */
            { T_DIRECT, SIP_MEDIA_FIXED, "HITACHI", "OPEN*", "*" },
            CAM_QUIRK_HILUNS, 2, 1024
      },
      {
            /*
             * This old revision of the TDC3600 is also SCSI-1, and
             * hangs upon serial number probing.
             */
            {
                  T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "TANDBERG",
                  " TDC 3600", "U07:"
            },
            CAM_QUIRK_NOSERIAL, /*mintags*/0, /*maxtags*/0
      },
      {
            /*
             * Maxtor Personal Storage 3000XT (Firewire)
             * hangs upon serial number probing.
             */
            {
                  T_DIRECT, SIP_MEDIA_FIXED, "Maxtor",
                  "1394 storage", "*"
            },
            CAM_QUIRK_NOSERIAL, /*mintags*/0, /*maxtags*/0
      },
      {
            /*
             * Would repond to all LUNs if asked for.
             */
            {
                  T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "CALIPER",
                  "CP150", "*"
            },
            CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
      },
      {
            /*
             * Would repond to all LUNs if asked for.
             */
            {
                  T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "KENNEDY",
                  "96X2*", "*"
            },
            CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
      },
      {
            /* Submitted by: Matthew Dodd <winter@jurai.net> */
            { T_PROCESSOR, SIP_MEDIA_FIXED, "Cabletrn", "EA41*", "*" },
            CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
      },
      {
            /* Submitted by: Matthew Dodd <winter@jurai.net> */
            { T_PROCESSOR, SIP_MEDIA_FIXED, "CABLETRN", "EA41*", "*" },
            CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
      },
      {
            /* TeraSolutions special settings for TRC-22 RAID */
            { T_DIRECT, SIP_MEDIA_FIXED, "TERASOLU", "TRC-22", "*" },
              /*quirks*/0, /*mintags*/55, /*maxtags*/255
      },
      {
            /* Veritas Storage Appliance */
            { T_DIRECT, SIP_MEDIA_FIXED, "VERITAS", "*", "*" },
              CAM_QUIRK_HILUNS, /*mintags*/2, /*maxtags*/1024
      },
      {
            /*
             * Would respond to all LUNs.  Device type and removable
             * flag are jumper-selectable.
             */
            { T_ANY, SIP_MEDIA_REMOVABLE|SIP_MEDIA_FIXED, "MaxOptix",
              "Tahiti 1", "*"
            },
            CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
      },
      {
            /* EasyRAID E5A aka. areca ARC-6010 */
            { T_DIRECT, SIP_MEDIA_FIXED, "easyRAID", "*", "*" },
              CAM_QUIRK_NOHILUNS, /*mintags*/2, /*maxtags*/255
      },
      {
            { T_ENCLOSURE, SIP_MEDIA_FIXED, "DP", "BACKPLANE", "*" },
            CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
      },
      {
            /* Default tagged queuing parameters for all devices */
            {
              T_ANY, SIP_MEDIA_REMOVABLE|SIP_MEDIA_FIXED,
              /*vendor*/"*", /*product*/"*", /*revision*/"*"
            },
            /*quirks*/0, /*mintags*/2, /*maxtags*/255
      },
};

static const int xpt_quirk_table_size =
      sizeof(xpt_quirk_table) / sizeof(*xpt_quirk_table);

typedef enum {
      DM_RET_COPY       = 0x01,
      DM_RET_FLAG_MASK  = 0x0f,
      DM_RET_NONE       = 0x00,
      DM_RET_STOP       = 0x10,
      DM_RET_DESCEND          = 0x20,
      DM_RET_ERROR            = 0x30,
      DM_RET_ACTION_MASK      = 0xf0
} dev_match_ret;

typedef enum {
      XPT_DEPTH_BUS,
      XPT_DEPTH_TARGET,
      XPT_DEPTH_DEVICE,
      XPT_DEPTH_PERIPH
} xpt_traverse_depth;

struct xpt_traverse_config {
      xpt_traverse_depth      depth;
      void              *tr_func;
      void              *tr_arg;
};

typedef     int   xpt_busfunc_t (struct cam_eb *bus, void *arg);
typedef     int   xpt_targetfunc_t (struct cam_et *target, void *arg);
typedef     int   xpt_devicefunc_t (struct cam_ed *device, void *arg);
typedef     int   xpt_periphfunc_t (struct cam_periph *periph, void *arg);
typedef int xpt_pdrvfunc_t (struct periph_driver **pdrv, void *arg);

/* Transport layer configuration information */
static struct xpt_softc xsoftc;

/* Queues for our software interrupt handler */
typedef TAILQ_HEAD(cam_isrq, ccb_hdr) cam_isrq_t;
static cam_isrq_t cam_bioq;
static struct mtx cam_bioq_lock;

/* "Pool" of inactive ccbs managed by xpt_alloc_ccb and xpt_free_ccb */
static SLIST_HEAD(,ccb_hdr) ccb_freeq;
static u_int xpt_max_ccbs;    /*
                         * Maximum size of ccb pool.  Modified as
                         * devices are added/removed or have their
                         * opening counts changed.
                         */
static u_int xpt_ccb_count;   /* Current count of allocated ccbs */

struct cam_periph *xpt_periph;

static periph_init_t xpt_periph_init;

static periph_init_t probe_periph_init;

static struct periph_driver xpt_driver =
{
      xpt_periph_init, "xpt",
      TAILQ_HEAD_INITIALIZER(xpt_driver.units)
};

static struct periph_driver probe_driver =
{
      probe_periph_init, "probe",
      TAILQ_HEAD_INITIALIZER(probe_driver.units)
};

PERIPHDRIVER_DECLARE(xpt, xpt_driver);
PERIPHDRIVER_DECLARE(probe, probe_driver);


static d_open_t xptopen;
static d_close_t xptclose;
static d_ioctl_t xptioctl;

static struct cdevsw xpt_cdevsw = {
      .d_version =      D_VERSION,
      .d_flags =  D_NEEDGIANT,
      .d_open =   xptopen,
      .d_close =  xptclose,
      .d_ioctl =  xptioctl,
      .d_name =   "xpt",
};

static struct intr_config_hook *xpt_config_hook;

static void dead_sim_action(struct cam_sim *sim, union ccb *ccb);
static void dead_sim_poll(struct cam_sim *sim);

/* Dummy SIM that is used when the real one has gone. */
static struct cam_sim cam_dead_sim = {
      .sim_action =     dead_sim_action,
      .sim_poll = dead_sim_poll,
      .sim_name = "dead_sim",
};

#define SIM_DEAD(sim)   ((sim) == &cam_dead_sim)

/* Registered busses */
static TAILQ_HEAD(,cam_eb) xpt_busses;
static u_int bus_generation;

/* Storage for debugging datastructures */
#ifdef      CAMDEBUG
struct cam_path *cam_dpath;
u_int32_t cam_dflags;
u_int32_t cam_debug_delay;
#endif

/* Pointers to software interrupt handlers */
static void *cambio_ih;

#if defined(CAM_DEBUG_FLAGS) && !defined(CAMDEBUG)
#error "You must have options CAMDEBUG to use options CAM_DEBUG_FLAGS"
#endif

/*
 * In order to enable the CAM_DEBUG_* options, the user must have CAMDEBUG
 * enabled.  Also, the user must have either none, or all of CAM_DEBUG_BUS,
 * CAM_DEBUG_TARGET, and CAM_DEBUG_LUN specified.
 */
#if defined(CAM_DEBUG_BUS) || defined(CAM_DEBUG_TARGET) \
    || defined(CAM_DEBUG_LUN)
#ifdef CAMDEBUG
#if !defined(CAM_DEBUG_BUS) || !defined(CAM_DEBUG_TARGET) \
    || !defined(CAM_DEBUG_LUN)
#error "You must define all or none of CAM_DEBUG_BUS, CAM_DEBUG_TARGET \
        and CAM_DEBUG_LUN"
#endif /* !CAM_DEBUG_BUS || !CAM_DEBUG_TARGET || !CAM_DEBUG_LUN */
#else /* !CAMDEBUG */
#error "You must use options CAMDEBUG if you use the CAM_DEBUG_* options"
#endif /* CAMDEBUG */
#endif /* CAM_DEBUG_BUS || CAM_DEBUG_TARGET || CAM_DEBUG_LUN */

/* Our boot-time initialization hook */
static int cam_module_event_handler(module_t, int /*modeventtype_t*/, void *);

static moduledata_t cam_moduledata = {
      "cam",
      cam_module_event_handler,
      NULL
};

static void xpt_init(void *);

DECLARE_MODULE(cam, cam_moduledata, SI_SUB_CONFIGURE, SI_ORDER_SECOND);
MODULE_VERSION(cam, 1);


static cam_status xpt_compile_path(struct cam_path *new_path,
                               struct cam_periph *perph,
                               path_id_t path_id,
                               target_id_t target_id,
                               lun_id_t lun_id);

static void       xpt_release_path(struct cam_path *path);

static void       xpt_async_bcast(struct async_list *async_head,
                              u_int32_t async_code,
                              struct cam_path *path,
                              void *async_arg);
static void       xpt_dev_async(u_int32_t async_code,
                              struct cam_eb *bus,
                              struct cam_et *target,
                              struct cam_ed *device,
                              void *async_arg);
static path_id_t xptnextfreepathid(void);
static path_id_t xptpathid(const char *sim_name, int sim_unit, int sim_bus);
static union ccb *xpt_get_ccb(struct cam_ed *device);
static int   xpt_schedule_dev(struct camq *queue, cam_pinfo *dev_pinfo,
                          u_int32_t new_priority);
static void  xpt_run_dev_allocq(struct cam_eb *bus);
static void  xpt_run_dev_sendq(struct cam_eb *bus);
static timeout_t xpt_release_devq_timeout;
static timeout_t xpt_release_simq_timeout;
static void  xpt_release_bus(struct cam_eb *bus);
static void  xpt_release_devq_device(struct cam_ed *dev, u_int count,
                               int run_queue);
static struct cam_et*
             xpt_alloc_target(struct cam_eb *bus, target_id_t target_id);
static void  xpt_release_target(struct cam_eb *bus, struct cam_et *target);
static struct cam_ed*
             xpt_alloc_device(struct cam_eb *bus, struct cam_et *target,
                          lun_id_t lun_id);
static void  xpt_release_device(struct cam_eb *bus, struct cam_et *target,
                            struct cam_ed *device);
static u_int32_t xpt_dev_ccbq_resize(struct cam_path *path, int newopenings);
static struct cam_eb*
             xpt_find_bus(path_id_t path_id);
static struct cam_et*
             xpt_find_target(struct cam_eb *bus, target_id_t target_id);
static struct cam_ed*
             xpt_find_device(struct cam_et *target, lun_id_t lun_id);
static void  xpt_scan_bus(struct cam_periph *periph, union ccb *ccb);
static void  xpt_scan_lun(struct cam_periph *periph,
                        struct cam_path *path, cam_flags flags,
                        union ccb *ccb);
static void  xptscandone(struct cam_periph *periph, union ccb *done_ccb);
static xpt_busfunc_t    xptconfigbuscountfunc;
static xpt_busfunc_t    xptconfigfunc;
static void  xpt_config(void *arg);
static xpt_devicefunc_t xptpassannouncefunc;
static void  xpt_finishconfig(struct cam_periph *periph, union ccb *ccb);
static void  xptaction(struct cam_sim *sim, union ccb *work_ccb);
static void  xptpoll(struct cam_sim *sim);
static void  camisr(void *);
#if 0
static void  xptstart(struct cam_periph *periph, union ccb *work_ccb);
static void  xptasync(struct cam_periph *periph,
                    u_int32_t code, cam_path *path);
#endif
static dev_match_ret    xptbusmatch(struct dev_match_pattern *patterns,
                            u_int num_patterns, struct cam_eb *bus);
static dev_match_ret    xptdevicematch(struct dev_match_pattern *patterns,
                               u_int num_patterns,
                               struct cam_ed *device);
static dev_match_ret    xptperiphmatch(struct dev_match_pattern *patterns,
                               u_int num_patterns,
                               struct cam_periph *periph);
static xpt_busfunc_t    xptedtbusfunc;
static xpt_targetfunc_t xptedttargetfunc;
static xpt_devicefunc_t xptedtdevicefunc;
static xpt_periphfunc_t xptedtperiphfunc;
static xpt_pdrvfunc_t   xptplistpdrvfunc;
static xpt_periphfunc_t xptplistperiphfunc;
static int        xptedtmatch(struct ccb_dev_match *cdm);
static int        xptperiphlistmatch(struct ccb_dev_match *cdm);
static int        xptbustraverse(struct cam_eb *start_bus,
                               xpt_busfunc_t *tr_func, void *arg);
static int        xpttargettraverse(struct cam_eb *bus,
                                struct cam_et *start_target,
                                xpt_targetfunc_t *tr_func, void *arg);
static int        xptdevicetraverse(struct cam_et *target,
                                struct cam_ed *start_device,
                                xpt_devicefunc_t *tr_func, void *arg);
static int        xptperiphtraverse(struct cam_ed *device,
                                struct cam_periph *start_periph,
                                xpt_periphfunc_t *tr_func, void *arg);
static int        xptpdrvtraverse(struct periph_driver **start_pdrv,
                              xpt_pdrvfunc_t *tr_func, void *arg);
static int        xptpdperiphtraverse(struct periph_driver **pdrv,
                                  struct cam_periph *start_periph,
                                  xpt_periphfunc_t *tr_func,
                                  void *arg);
static xpt_busfunc_t    xptdefbusfunc;
static xpt_targetfunc_t xptdeftargetfunc;
static xpt_devicefunc_t xptdefdevicefunc;
static xpt_periphfunc_t xptdefperiphfunc;
static int        xpt_for_all_busses(xpt_busfunc_t *tr_func, void *arg);
#ifdef notusedyet
static int        xpt_for_all_targets(xpt_targetfunc_t *tr_func,
                                  void *arg);
#endif
static int        xpt_for_all_devices(xpt_devicefunc_t *tr_func,
                                  void *arg);
#ifdef notusedyet
static int        xpt_for_all_periphs(xpt_periphfunc_t *tr_func,
                                  void *arg);
#endif
static xpt_devicefunc_t xptsetasyncfunc;
static xpt_busfunc_t    xptsetasyncbusfunc;
static cam_status xptregister(struct cam_periph *periph,
                            void *arg);
static cam_status proberegister(struct cam_periph *periph,
                              void *arg);
static void  probeschedule(struct cam_periph *probe_periph);
static void  probestart(struct cam_periph *periph, union ccb *start_ccb);
static void  proberequestdefaultnegotiation(struct cam_periph *periph);
static void  probedone(struct cam_periph *periph, union ccb *done_ccb);
static void  probecleanup(struct cam_periph *periph);
static void  xpt_find_quirk(struct cam_ed *device);
#ifdef CAM_NEW_TRAN_CODE
static void  xpt_devise_transport(struct cam_path *path);
#endif /* CAM_NEW_TRAN_CODE */
static void  xpt_set_transfer_settings(struct ccb_trans_settings *cts,
                                 struct cam_ed *device,
                                 int async_update);
static void  xpt_toggle_tags(struct cam_path *path);
static void  xpt_start_tags(struct cam_path *path);
static __inline int xpt_schedule_dev_allocq(struct cam_eb *bus,
                                  struct cam_ed *dev);
static __inline int xpt_schedule_dev_sendq(struct cam_eb *bus,
                                 struct cam_ed *dev);
static __inline int periph_is_queued(struct cam_periph *periph);
static __inline int device_is_alloc_queued(struct cam_ed *device);
static __inline int device_is_send_queued(struct cam_ed *device);
static __inline int dev_allocq_is_runnable(struct cam_devq *devq);

static __inline int
xpt_schedule_dev_allocq(struct cam_eb *bus, struct cam_ed *dev)
{
      int retval;

      if (dev->ccbq.devq_openings > 0) {
            if ((dev->flags & CAM_DEV_RESIZE_QUEUE_NEEDED) != 0) {
                  cam_ccbq_resize(&dev->ccbq,
                              dev->ccbq.dev_openings
                              + dev->ccbq.dev_active);
                  dev->flags &= ~CAM_DEV_RESIZE_QUEUE_NEEDED;
            }
            /*
             * The priority of a device waiting for CCB resources
             * is that of the the highest priority peripheral driver
             * enqueued.
             */
            retval = xpt_schedule_dev(&bus->sim->devq->alloc_queue,
                                &dev->alloc_ccb_entry.pinfo,
                                CAMQ_GET_HEAD(&dev->drvq)->priority);   
      } else {
            retval = 0;
      }

      return (retval);
}

static __inline int
xpt_schedule_dev_sendq(struct cam_eb *bus, struct cam_ed *dev)
{
      int   retval;

      if (dev->ccbq.dev_openings > 0) {
            /*
             * The priority of a device waiting for controller
             * resources is that of the the highest priority CCB
             * enqueued.
             */
            retval =
                xpt_schedule_dev(&bus->sim->devq->send_queue,
                             &dev->send_ccb_entry.pinfo,
                             CAMQ_GET_HEAD(&dev->ccbq.queue)->priority);
      } else {
            retval = 0;
      }
      return (retval);
}

static __inline int
periph_is_queued(struct cam_periph *periph)
{
      return (periph->pinfo.index != CAM_UNQUEUED_INDEX);
}

static __inline int
device_is_alloc_queued(struct cam_ed *device)
{
      return (device->alloc_ccb_entry.pinfo.index != CAM_UNQUEUED_INDEX);
}

static __inline int
device_is_send_queued(struct cam_ed *device)
{
      return (device->send_ccb_entry.pinfo.index != CAM_UNQUEUED_INDEX);
}

static __inline int
dev_allocq_is_runnable(struct cam_devq *devq)
{
      /*
       * Have work to do.
       * Have space to do more work.
       * Allowed to do work.
       */
      return ((devq->alloc_queue.qfrozen_cnt == 0)
           && (devq->alloc_queue.entries > 0)
           && (devq->alloc_openings > 0));
}

static void
xpt_periph_init()
{
      make_dev(&xpt_cdevsw, 0, UID_ROOT, GID_OPERATOR, 0600, "xpt0");
}

static void
probe_periph_init()
{
}


static void
xptdone(struct cam_periph *periph, union ccb *done_ccb)
{
      /* Caller will release the CCB */
      wakeup(&done_ccb->ccb_h.cbfcnp);
}

static int
xptopen(struct cdev *dev, int flags, int fmt, struct thread *td)
{
      int unit;

      unit = minor(dev) & 0xff;

      /*
       * Only allow read-write access.
       */
      if (((flags & FWRITE) == 0) || ((flags & FREAD) == 0))
            return(EPERM);

      /*
       * We don't allow nonblocking access.
       */
      if ((flags & O_NONBLOCK) != 0) {
            printf("xpt%d: can't do nonblocking access\n", unit);
            return(ENODEV);
      }

      /*
       * We only have one transport layer right now.  If someone accesses
       * us via something other than minor number 1, point out their
       * mistake.
       */
      if (unit != 0) {
            printf("xptopen: got invalid xpt unit %d\n", unit);
            return(ENXIO);
      }

      /* Mark ourselves open */
      xsoftc.flags |= XPT_FLAG_OPEN;
      
      return(0);
}

static int
xptclose(struct cdev *dev, int flag, int fmt, struct thread *td)
{
      int unit;

      unit = minor(dev) & 0xff;

      /*
       * We only have one transport layer right now.  If someone accesses
       * us via something other than minor number 1, point out their
       * mistake.
       */
      if (unit != 0) {
            printf("xptclose: got invalid xpt unit %d\n", unit);
            return(ENXIO);
      }

      /* Mark ourselves closed */
      xsoftc.flags &= ~XPT_FLAG_OPEN;

      return(0);
}

static int
xptioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
{
      int unit, error;

      error = 0;
      unit = minor(dev) & 0xff;

      /*
       * We only have one transport layer right now.  If someone accesses
       * us via something other than minor number 1, point out their
       * mistake.
       */
      if (unit != 0) {
            printf("xptioctl: got invalid xpt unit %d\n", unit);
            return(ENXIO);
      }

      switch(cmd) {
      /*
       * For the transport layer CAMIOCOMMAND ioctl, we really only want
       * to accept CCB types that don't quite make sense to send through a
       * passthrough driver. XPT_PATH_INQ is an exception to this, as stated
       * in the CAM spec.
       */
      case CAMIOCOMMAND: {
            union ccb *ccb;
            union ccb *inccb;

            inccb = (union ccb *)addr;

            switch(inccb->ccb_h.func_code) {
            case XPT_SCAN_BUS:
            case XPT_RESET_BUS:
                  if ((inccb->ccb_h.target_id != CAM_TARGET_WILDCARD)
                   || (inccb->ccb_h.target_lun != CAM_LUN_WILDCARD)) {
                        error = EINVAL;
                        break;
                  }
                  /* FALLTHROUGH */
            case XPT_PATH_INQ:
            case XPT_ENG_INQ:
            case XPT_SCAN_LUN:

                  ccb = xpt_alloc_ccb();

                  /*
                   * Create a path using the bus, target, and lun the
                   * user passed in.
                   */
                  if (xpt_create_path(&ccb->ccb_h.path, xpt_periph,
                                  inccb->ccb_h.path_id,
                                  inccb->ccb_h.target_id,
                                  inccb->ccb_h.target_lun) !=
                                  CAM_REQ_CMP){
                        error = EINVAL;
                        xpt_free_ccb(ccb);
                        break;
                  }
                  /* Ensure all of our fields are correct */
                  xpt_setup_ccb(&ccb->ccb_h, ccb->ccb_h.path,
                              inccb->ccb_h.pinfo.priority);
                  xpt_merge_ccb(ccb, inccb);
                  ccb->ccb_h.cbfcnp = xptdone;
                  cam_periph_runccb(ccb, NULL, 0, 0, NULL);
                  bcopy(ccb, inccb, sizeof(union ccb));
                  xpt_free_path(ccb->ccb_h.path);
                  xpt_free_ccb(ccb);
                  break;

            case XPT_DEBUG: {
                  union ccb ccb;

                  /*
                   * This is an immediate CCB, so it's okay to
                   * allocate it on the stack.
                   */

                  /*
                   * Create a path using the bus, target, and lun the
                   * user passed in.
                   */
                  if (xpt_create_path(&ccb.ccb_h.path, xpt_periph,
                                  inccb->ccb_h.path_id,
                                  inccb->ccb_h.target_id,
                                  inccb->ccb_h.target_lun) !=
                                  CAM_REQ_CMP){
                        error = EINVAL;
                        break;
                  }
                  /* Ensure all of our fields are correct */
                  xpt_setup_ccb(&ccb.ccb_h, ccb.ccb_h.path,
                              inccb->ccb_h.pinfo.priority);
                  xpt_merge_ccb(&ccb, inccb);
                  ccb.ccb_h.cbfcnp = xptdone;
                  xpt_action(&ccb);
                  bcopy(&ccb, inccb, sizeof(union ccb));
                  xpt_free_path(ccb.ccb_h.path);
                  break;

            }
            case XPT_DEV_MATCH: {
                  struct cam_periph_map_info mapinfo;
                  struct cam_path *old_path;

                  /*
                   * We can't deal with physical addresses for this
                   * type of transaction.
                   */
                  if (inccb->ccb_h.flags & CAM_DATA_PHYS) {
                        error = EINVAL;
                        break;
                  }

                  /*
                   * Save this in case the caller had it set to
                   * something in particular.
                   */
                  old_path = inccb->ccb_h.path;

                  /*
                   * We really don't need a path for the matching
                   * code.  The path is needed because of the
                   * debugging statements in xpt_action().  They
                   * assume that the CCB has a valid path.
                   */
                  inccb->ccb_h.path = xpt_periph->path;

                  bzero(&mapinfo, sizeof(mapinfo));

                  /*
                   * Map the pattern and match buffers into kernel
                   * virtual address space.
                   */
                  error = cam_periph_mapmem(inccb, &mapinfo);

                  if (error) {
                        inccb->ccb_h.path = old_path;
                        break;
                  }

                  /*
                   * This is an immediate CCB, we can send it on directly.
                   */
                  xpt_action(inccb);

                  /*
                   * Map the buffers back into user space.
                   */
                  cam_periph_unmapmem(inccb, &mapinfo);

                  inccb->ccb_h.path = old_path;

                  error = 0;
                  break;
            }
            default:
                  error = ENOTSUP;
                  break;
            }
            break;
      }
      /*
       * This is the getpassthru ioctl. It takes a XPT_GDEVLIST ccb as input,
       * with the periphal driver name and unit name filled in.  The other
       * fields don't really matter as input.  The passthrough driver name
       * ("pass"), and unit number are passed back in the ccb.  The current
       * device generation number, and the index into the device peripheral
       * driver list, and the status are also passed back.  Note that
       * since we do everything in one pass, unlike the XPT_GDEVLIST ccb,
       * we never return a status of CAM_GDEVLIST_LIST_CHANGED.  It is
       * (or rather should be) impossible for the device peripheral driver
       * list to change since we look at the whole thing in one pass, and
       * we do it with splcam protection.
       * 
       */
      case CAMGETPASSTHRU: {
            union ccb *ccb;
            struct cam_periph *periph;
            struct periph_driver **p_drv;
            char   *name;
            u_int unit;
            u_int cur_generation;
            int base_periph_found;
            int splbreaknum;
            int s;

            ccb = (union ccb *)addr;
            unit = ccb->cgdl.unit_number;
            name = ccb->cgdl.periph_name;
            /*
             * Every 100 devices, we want to drop our spl protection to
             * give the software interrupt handler a chance to run.
             * Most systems won't run into this check, but this should
             * avoid starvation in the software interrupt handler in
             * large systems.
             */
            splbreaknum = 100;

            ccb = (union ccb *)addr;

            base_periph_found = 0;

            /*
             * Sanity check -- make sure we don't get a null peripheral
             * driver name.
             */
            if (*ccb->cgdl.periph_name == '\0') {
                  error = EINVAL;
                  break;
            }

            /* Keep the list from changing while we traverse it */
            s = splcam();
ptstartover:
            cur_generation = xsoftc.generation;

            /* first find our driver in the list of drivers */
            for (p_drv = periph_drivers; *p_drv != NULL; p_drv++)
                  if (strcmp((*p_drv)->driver_name, name) == 0)
                        break;

            if (*p_drv == NULL) {
                  splx(s);
                  ccb->ccb_h.status = CAM_REQ_CMP_ERR;
                  ccb->cgdl.status = CAM_GDEVLIST_ERROR;
                  *ccb->cgdl.periph_name = '\0';
                  ccb->cgdl.unit_number = 0;
                  error = ENOENT;
                  break;
            }     

            /*
             * Run through every peripheral instance of this driver
             * and check to see whether it matches the unit passed
             * in by the user.  If it does, get out of the loops and
             * find the passthrough driver associated with that
             * peripheral driver.
             */
            for (periph = TAILQ_FIRST(&(*p_drv)->units); periph != NULL;
                 periph = TAILQ_NEXT(periph, unit_links)) {

                  if (periph->unit_number == unit) {
                        break;
                  } else if (--splbreaknum == 0) {
                        splx(s);
                        s = splcam();
                        splbreaknum = 100;
                        if (cur_generation != xsoftc.generation)
                               goto ptstartover;
                  }
            }
            /*
             * If we found the peripheral driver that the user passed
             * in, go through all of the peripheral drivers for that
             * particular device and look for a passthrough driver.
             */
            if (periph != NULL) {
                  struct cam_ed *device;
                  int i;

                  base_periph_found = 1;
                  device = periph->path->device;
                  for (i = 0, periph = SLIST_FIRST(&device->periphs);
                       periph != NULL;
                       periph = SLIST_NEXT(periph, periph_links), i++) {
                        /*
                         * Check to see whether we have a
                         * passthrough device or not. 
                         */
                        if (strcmp(periph->periph_name, "pass") == 0) {
                              /*
                               * Fill in the getdevlist fields.
                               */
                              strcpy(ccb->cgdl.periph_name,
                                     periph->periph_name);
                              ccb->cgdl.unit_number =
                                    periph->unit_number;
                              if (SLIST_NEXT(periph, periph_links))
                                    ccb->cgdl.status =
                                          CAM_GDEVLIST_MORE_DEVS;
                              else
                                    ccb->cgdl.status =
                                           CAM_GDEVLIST_LAST_DEVICE;
                              ccb->cgdl.generation =
                                    device->generation;
                              ccb->cgdl.index = i;
                              /*
                               * Fill in some CCB header fields
                               * that the user may want.
                               */
                              ccb->ccb_h.path_id =
                                    periph->path->bus->path_id;
                              ccb->ccb_h.target_id =
                                    periph->path->target->target_id;
                              ccb->ccb_h.target_lun =
                                    periph->path->device->lun_id;
                              ccb->ccb_h.status = CAM_REQ_CMP;
                              break;
                        }
                  }
            }

            /*
             * If the periph is null here, one of two things has
             * happened.  The first possibility is that we couldn't
             * find the unit number of the particular peripheral driver
             * that the user is asking about.  e.g. the user asks for
             * the passthrough driver for "da11".  We find the list of
             * "da" peripherals all right, but there is no unit 11.
             * The other possibility is that we went through the list
             * of peripheral drivers attached to the device structure,
             * but didn't find one with the name "pass".  Either way,
             * we return ENOENT, since we couldn't find something.
             */
            if (periph == NULL) {
                  ccb->ccb_h.status = CAM_REQ_CMP_ERR;
                  ccb->cgdl.status = CAM_GDEVLIST_ERROR;
                  *ccb->cgdl.periph_name = '\0';
                  ccb->cgdl.unit_number = 0;
                  error = ENOENT;
                  /*
                   * It is unfortunate that this is even necessary,
                   * but there are many, many clueless users out there.
                   * If this is true, the user is looking for the
                   * passthrough driver, but doesn't have one in his
                   * kernel.
                   */
                  if (base_periph_found == 1) {
                        printf("xptioctl: pass driver is not in the "
                               "kernel\n");
                        printf("xptioctl: put \"device pass0\" in "
                               "your kernel config file\n");
                  }
            }
            splx(s);
            break;
            }
      default:
            error = ENOTTY;
            break;
      }

      return(error);
}

static int
cam_module_event_handler(module_t mod, int what, void *arg)
{
      if (what == MOD_LOAD) {
            xpt_init(NULL);
      } else if (what == MOD_UNLOAD) {
            return EBUSY;
      } else {
            return EOPNOTSUPP;
      }

      return 0;
}

/* thread to handle bus rescans */
static TAILQ_HEAD(, ccb_hdr) ccb_scanq;
static void
xpt_scanner_thread(void *dummy)
{
      mtx_lock(&Giant);
      for (;;) {
            union ccb *ccb;
            tsleep(&ccb_scanq, PRIBIO, "ccb_scanq", 0);
            while ((ccb = (union ccb *)TAILQ_FIRST(&ccb_scanq)) != NULL) {
                  TAILQ_REMOVE(&ccb_scanq, &ccb->ccb_h, sim_links.tqe);
                  ccb->ccb_h.func_code = XPT_SCAN_BUS;
                  ccb->ccb_h.cbfcnp = xptdone;
                  xpt_setup_ccb(&ccb->ccb_h, ccb->ccb_h.path, 5);
                  cam_periph_runccb(ccb, NULL, 0, 0, NULL);
                  xpt_free_path(ccb->ccb_h.path);
                  xpt_free_ccb(ccb);
            }
      }
}

void
xpt_rescan(union ccb *ccb)
{
      struct ccb_hdr *hdr;
      GIANT_REQUIRED;
      /*
       * Don't make duplicate entries for the same paths.
       */
      TAILQ_FOREACH(hdr, &ccb_scanq, sim_links.tqe) {
            if (xpt_path_comp(hdr->path, ccb->ccb_h.path) == 0) {
                  xpt_print(ccb->ccb_h.path, "rescan already queued\n");
                  xpt_free_path(ccb->ccb_h.path);
                  xpt_free_ccb(ccb);
                  return;
            }
      }
      TAILQ_INSERT_TAIL(&ccb_scanq, &ccb->ccb_h, sim_links.tqe);
      wakeup(&ccb_scanq);
}

/* Functions accessed by the peripheral drivers */
static void
xpt_init(void *dummy)
{
      struct cam_sim *xpt_sim;
      struct cam_path *path;
      struct cam_devq *devq;
      cam_status status;

      TAILQ_INIT(&xpt_busses);
      TAILQ_INIT(&cam_bioq);
      SLIST_INIT(&ccb_freeq);
      TAILQ_INIT(&ccb_scanq);
      STAILQ_INIT(&highpowerq);

      mtx_init(&cam_bioq_lock, "CAM BIOQ lock", NULL, MTX_DEF);

      /*
       * The xpt layer is, itself, the equivelent of a SIM.
       * Allow 16 ccbs in the ccb pool for it.  This should
       * give decent parallelism when we probe busses and
       * perform other XPT functions.
       */
      devq = cam_simq_alloc(16);
      xpt_sim = cam_sim_alloc(xptaction,
                        xptpoll,
                        "xpt",
                        /*softc*/NULL,
                        /*unit*/0,
                        /*max_dev_transactions*/0,
                        /*max_tagged_dev_transactions*/0,
                        devq);
      xpt_max_ccbs = 16;
                        
      if ((status = xpt_bus_register(xpt_sim, /*bus #*/0)) != CAM_SUCCESS) {
            printf("xpt_init: xpt_bus_register failed with status %#x,"
                   " failing attach\n", status);
            return;
      }

      /*
       * Looking at the XPT from the SIM layer, the XPT is
       * the equivelent of a peripheral driver.  Allocate
       * a peripheral driver entry for us.
       */
      if ((status = xpt_create_path(&path, NULL, CAM_XPT_PATH_ID,
                              CAM_TARGET_WILDCARD,
                              CAM_LUN_WILDCARD)) != CAM_REQ_CMP) {
            printf("xpt_init: xpt_create_path failed with status %#x,"
                   " failing attach\n", status);
            return;
      }

      cam_periph_alloc(xptregister, NULL, NULL, NULL, "xpt", CAM_PERIPH_BIO,
                   path, NULL, 0, NULL);
      xpt_free_path(path);

      xpt_sim->softc = xpt_periph;

      /*
       * Register a callback for when interrupts are enabled.
       */
      xpt_config_hook =
          (struct intr_config_hook *)malloc(sizeof(struct intr_config_hook),
                                    M_TEMP, M_NOWAIT | M_ZERO);
      if (xpt_config_hook == NULL) {
            printf("xpt_init: Cannot malloc config hook "
                   "- failing attach\n");
            return;
      }

      xpt_config_hook->ich_func = xpt_config;
      if (config_intrhook_establish(xpt_config_hook) != 0) {
            free (xpt_config_hook, M_TEMP);
            printf("xpt_init: config_intrhook_establish failed "
                   "- failing attach\n");
      }

      /* fire up rescan thread */
      if (kthread_create(xpt_scanner_thread, NULL, NULL, 0, 0, "xpt_thrd")) {
            printf("xpt_init: failed to create rescan thread\n");
      }
      /* Install our software interrupt handlers */
      swi_add(NULL, "cambio", camisr, &cam_bioq, SWI_CAMBIO, 0, &cambio_ih);
}

static cam_status
xptregister(struct cam_periph *periph, void *arg)
{
      if (periph == NULL) {
            printf("xptregister: periph was NULL!!\n");
            return(CAM_REQ_CMP_ERR);
      }

      periph->softc = NULL;

      xpt_periph = periph;

      return(CAM_REQ_CMP);
}

int32_t
xpt_add_periph(struct cam_periph *periph)
{
      struct cam_ed *device;
      int32_t      status;
      struct periph_list *periph_head;

      GIANT_REQUIRED;

      device = periph->path->device;

      periph_head = &device->periphs;

      status = CAM_REQ_CMP;

      if (device != NULL) {
            int s;

            /*
             * Make room for this peripheral
             * so it will fit in the queue
             * when it's scheduled to run
             */
            s = splsoftcam();
            status = camq_resize(&device->drvq,
                             device->drvq.array_size + 1);

            device->generation++;

            SLIST_INSERT_HEAD(periph_head, periph, periph_links);

            splx(s);
      }

      xsoftc.generation++;

      return (status);
}

void
xpt_remove_periph(struct cam_periph *periph)
{
      struct cam_ed *device;

      GIANT_REQUIRED;

      device = periph->path->device;

      if (device != NULL) {
            int s;
            struct periph_list *periph_head;

            periph_head = &device->periphs;
            
            /* Release the slot for this peripheral */
            s = splsoftcam();
            camq_resize(&device->drvq, device->drvq.array_size - 1);

            device->generation++;

            SLIST_REMOVE(periph_head, periph, cam_periph, periph_links);

            splx(s);
      }

      xsoftc.generation++;

}

#ifdef CAM_NEW_TRAN_CODE

void
xpt_announce_periph(struct cam_periph *periph, char *announce_string)
{
      struct      ccb_pathinq cpi;
      struct      ccb_trans_settings cts;
      struct      cam_path *path;
      u_int speed;
      u_int freq;
      u_int mb;
      int   s;

      GIANT_REQUIRED;

      path = periph->path;
      /*
       * To ensure that this is printed in one piece,
       * mask out CAM interrupts.
       */
      s = splsoftcam();
      printf("%s%d at %s%d bus %d target %d lun %d\n",
             periph->periph_name, periph->unit_number,
             path->bus->sim->sim_name,
             path->bus->sim->unit_number,
             path->bus->sim->bus_id,
             path->target->target_id,
             path->device->lun_id);
      printf("%s%d: ", periph->periph_name, periph->unit_number);
      scsi_print_inquiry(&path->device->inq_data);
      if (bootverbose && path->device->serial_num_len > 0) {
            /* Don't wrap the screen  - print only the first 60 chars */
            printf("%s%d: Serial Number %.60s\n", periph->periph_name,
                   periph->unit_number, path->device->serial_num);
      }
      xpt_setup_ccb(&cts.ccb_h, path, /*priority*/1);
      cts.ccb_h.func_code = XPT_GET_TRAN_SETTINGS;
      cts.type = CTS_TYPE_CURRENT_SETTINGS;
      xpt_action((union ccb*)&cts);

      /* Ask the SIM for its base transfer speed */
      xpt_setup_ccb(&cpi.ccb_h, path, /*priority*/1);
      cpi.ccb_h.func_code = XPT_PATH_INQ;
      xpt_action((union ccb *)&cpi);

      speed = cpi.base_transfer_speed;
      freq = 0;
      if (cts.ccb_h.status == CAM_REQ_CMP && cts.transport == XPORT_SPI) {
            struct      ccb_trans_settings_spi *spi;

            spi = &cts.xport_specific.spi;
            if ((spi->valid & CTS_SPI_VALID_SYNC_OFFSET) != 0
              && spi->sync_offset != 0) {
                  freq = scsi_calc_syncsrate(spi->sync_period);
                  speed = freq;
            }

            if ((spi->valid & CTS_SPI_VALID_BUS_WIDTH) != 0)
                  speed *= (0x01 << spi->bus_width);
      }

      if (cts.ccb_h.status == CAM_REQ_CMP && cts.transport == XPORT_FC) {
            struct      ccb_trans_settings_fc *fc = &cts.xport_specific.fc;
            if (fc->valid & CTS_FC_VALID_SPEED) {
                  speed = fc->bitrate;
            }
      }

      mb = speed / 1000;
      if (mb > 0)
            printf("%s%d: %d.%03dMB/s transfers",
                   periph->periph_name, periph->unit_number,
                   mb, speed % 1000);
      else
            printf("%s%d: %dKB/s transfers", periph->periph_name,
                   periph->unit_number, speed);
      /* Report additional information about SPI connections */
      if (cts.ccb_h.status == CAM_REQ_CMP && cts.transport == XPORT_SPI) {
            struct      ccb_trans_settings_spi *spi;

            spi = &cts.xport_specific.spi;
            if (freq != 0) {
                  printf(" (%d.%03dMHz%s, offset %d", freq / 1000,
                         freq % 1000,
                         (spi->ppr_options & MSG_EXT_PPR_DT_REQ) != 0
                       ? " DT" : "",
                         spi->sync_offset);
            }
            if ((spi->valid & CTS_SPI_VALID_BUS_WIDTH) != 0
             && spi->bus_width > 0) {
                  if (freq != 0) {
                        printf(", ");
                  } else {
                        printf(" (");
                  }
                  printf("%dbit)", 8 * (0x01 << spi->bus_width));
            } else if (freq != 0) {
                  printf(")");
            }
      }
      if (cts.ccb_h.status == CAM_REQ_CMP && cts.transport == XPORT_FC) {
            struct      ccb_trans_settings_fc *fc;

            fc = &cts.xport_specific.fc;
            if (fc->valid & CTS_FC_VALID_WWNN)
                  printf(" WWNN 0x%llx", (long long) fc->wwnn);
            if (fc->valid & CTS_FC_VALID_WWPN)
                  printf(" WWPN 0x%llx", (long long) fc->wwpn);
            if (fc->valid & CTS_FC_VALID_PORT)
                  printf(" PortID 0x%x", fc->port);
      }

      if (path->device->inq_flags & SID_CmdQue
       || path->device->flags & CAM_DEV_TAG_AFTER_COUNT) {
            printf("\n%s%d: Tagged Queueing Enabled",
                   periph->periph_name, periph->unit_number);
      }
      printf("\n");

      /*
       * We only want to print the caller's announce string if they've
       * passed one in..
       */
      if (announce_string != NULL)
            printf("%s%d: %s\n", periph->periph_name,
                   periph->unit_number, announce_string);
      splx(s);
}
#else /* CAM_NEW_TRAN_CODE */
void
xpt_announce_periph(struct cam_periph *periph, char *announce_string)
{
      int s;
      u_int mb;
      struct cam_path *path;
      struct ccb_trans_settings cts;

      GIANT_REQUIRED;

      path = periph->path;
      /*
       * To ensure that this is printed in one piece,
       * mask out CAM interrupts.
       */
      s = splsoftcam();
      printf("%s%d at %s%d bus %d target %d lun %d\n",
             periph->periph_name, periph->unit_number,
             path->bus->sim->sim_name,
             path->bus->sim->unit_number,
             path->bus->sim->bus_id,
             path->target->target_id,
             path->device->lun_id);
      printf("%s%d: ", periph->periph_name, periph->unit_number);
      scsi_print_inquiry(&path->device->inq_data);
      if ((bootverbose)
       && (path->device->serial_num_len > 0)) {
            /* Don't wrap the screen  - print only the first 60 chars */
            printf("%s%d: Serial Number %.60s\n", periph->periph_name,
                   periph->unit_number, path->device->serial_num);
      }
      xpt_setup_ccb(&cts.ccb_h, path, /*priority*/1);
      cts.ccb_h.func_code = XPT_GET_TRAN_SETTINGS;
      cts.flags = CCB_TRANS_CURRENT_SETTINGS;
      xpt_action((union ccb*)&cts);
      if (cts.ccb_h.status == CAM_REQ_CMP) {
            u_int speed;
            u_int freq;

            if ((cts.valid & CCB_TRANS_SYNC_OFFSET_VALID) != 0
              && cts.sync_offset != 0) {
                  freq = scsi_calc_syncsrate(cts.sync_period);
                  speed = freq;
            } else {
                  struct ccb_pathinq cpi;

                  /* Ask the SIM for its base transfer speed */
                  xpt_setup_ccb(&cpi.ccb_h, path, /*priority*/1);
                  cpi.ccb_h.func_code = XPT_PATH_INQ;
                  xpt_action((union ccb *)&cpi);

                  speed = cpi.base_transfer_speed;
                  freq = 0;
            }
            if ((cts.valid & CCB_TRANS_BUS_WIDTH_VALID) != 0)
                  speed *= (0x01 << cts.bus_width);
            mb = speed / 1000;
            if (mb > 0)
                  printf("%s%d: %d.%03dMB/s transfers",
                         periph->periph_name, periph->unit_number,
                         mb, speed % 1000);
            else
                  printf("%s%d: %dKB/s transfers", periph->periph_name,
                         periph->unit_number, speed);
            if ((cts.valid & CCB_TRANS_SYNC_OFFSET_VALID) != 0
             && cts.sync_offset != 0) {
                  printf(" (%d.%03dMHz, offset %d", freq / 1000,
                         freq % 1000, cts.sync_offset);
            }
            if ((cts.valid & CCB_TRANS_BUS_WIDTH_VALID) != 0
             && cts.bus_width > 0) {
                  if ((cts.valid & CCB_TRANS_SYNC_OFFSET_VALID) != 0
                   && cts.sync_offset != 0) {
                        printf(", ");
                  } else {
                        printf(" (");
                  }
                  printf("%dbit)", 8 * (0x01 << cts.bus_width));
            } else if ((cts.valid & CCB_TRANS_SYNC_OFFSET_VALID) != 0
                  && cts.sync_offset != 0) {
                  printf(")");
            }

            if (path->device->inq_flags & SID_CmdQue
             || path->device->flags & CAM_DEV_TAG_AFTER_COUNT) {
                  printf(", Tagged Queueing Enabled");
            }

            printf("\n");
      } else if (path->device->inq_flags & SID_CmdQue
            || path->device->flags & CAM_DEV_TAG_AFTER_COUNT) {
            printf("%s%d: Tagged Queueing Enabled\n",
                   periph->periph_name, periph->unit_number);
      }

      /*
       * We only want to print the caller's announce string if they've
       * passed one in..
       */
      if (announce_string != NULL)
            printf("%s%d: %s\n", periph->periph_name,
                   periph->unit_number, announce_string);
      splx(s);
}

#endif /* CAM_NEW_TRAN_CODE */

static dev_match_ret
xptbusmatch(struct dev_match_pattern *patterns, u_int num_patterns,
          struct cam_eb *bus)
{
      dev_match_ret retval;
      int i;

      retval = DM_RET_NONE;

      /*
       * If we aren't given something to match against, that's an error.
       */
      if (bus == NULL)
            return(DM_RET_ERROR);

      /*
       * If there are no match entries, then this bus matches no
       * matter what.
       */
      if ((patterns == NULL) || (num_patterns == 0))
            return(DM_RET_DESCEND | DM_RET_COPY);

      for (i = 0; i < num_patterns; i++) {
            struct bus_match_pattern *cur_pattern;

            /*
             * If the pattern in question isn't for a bus node, we
             * aren't interested.  However, we do indicate to the
             * calling routine that we should continue descending the
             * tree, since the user wants to match against lower-level
             * EDT elements.
             */
            if (patterns[i].type != DEV_MATCH_BUS) {
                  if ((retval & DM_RET_ACTION_MASK) == DM_RET_NONE)
                        retval |= DM_RET_DESCEND;
                  continue;
            }

            cur_pattern = &patterns[i].pattern.bus_pattern;

            /*
             * If they want to match any bus node, we give them any
             * device node.
             */
            if (cur_pattern->flags == BUS_MATCH_ANY) {
                  /* set the copy flag */
                  retval |= DM_RET_COPY;

                  /*
                   * If we've already decided on an action, go ahead
                   * and return.
                   */
                  if ((retval & DM_RET_ACTION_MASK) != DM_RET_NONE)
                        return(retval);
            }

            /*
             * Not sure why someone would do this...
             */
            if (cur_pattern->flags == BUS_MATCH_NONE)
                  continue;

            if (((cur_pattern->flags & BUS_MATCH_PATH) != 0)
             && (cur_pattern->path_id != bus->path_id))
                  continue;

            if (((cur_pattern->flags & BUS_MATCH_BUS_ID) != 0)
             && (cur_pattern->bus_id != bus->sim->bus_id))
                  continue;

            if (((cur_pattern->flags & BUS_MATCH_UNIT) != 0)
             && (cur_pattern->unit_number != bus->sim->unit_number))
                  continue;

            if (((cur_pattern->flags & BUS_MATCH_NAME) != 0)
             && (strncmp(cur_pattern->dev_name, bus->sim->sim_name,
                       DEV_IDLEN) != 0))
                  continue;

            /*
             * If we get to this point, the user definitely wants 
             * information on this bus.  So tell the caller to copy the
             * data out.
             */
            retval |= DM_RET_COPY;

            /*
             * If the return action has been set to descend, then we
             * know that we've already seen a non-bus matching
             * expression, therefore we need to further descend the tree.
             * This won't change by continuing around the loop, so we
             * go ahead and return.  If we haven't seen a non-bus
             * matching expression, we keep going around the loop until
             * we exhaust the matching expressions.  We'll set the stop
             * flag once we fall out of the loop.
             */
            if ((retval & DM_RET_ACTION_MASK) == DM_RET_DESCEND)
                  return(retval);
      }

      /*
       * If the return action hasn't been set to descend yet, that means
       * we haven't seen anything other than bus matching patterns.  So
       * tell the caller to stop descending the tree -- the user doesn't
       * want to match against lower level tree elements.
       */
      if ((retval & DM_RET_ACTION_MASK) == DM_RET_NONE)
            retval |= DM_RET_STOP;

      return(retval);
}

static dev_match_ret
xptdevicematch(struct dev_match_pattern *patterns, u_int num_patterns,
             struct cam_ed *device)
{
      dev_match_ret retval;
      int i;

      retval = DM_RET_NONE;

      /*
       * If we aren't given something to match against, that's an error.
       */
      if (device == NULL)
            return(DM_RET_ERROR);

      /*
       * If there are no match entries, then this device matches no
       * matter what.
       */
      if ((patterns == NULL) || (num_patterns == 0))
            return(DM_RET_DESCEND | DM_RET_COPY);

      for (i = 0; i < num_patterns; i++) {
            struct device_match_pattern *cur_pattern;

            /*
             * If the pattern in question isn't for a device node, we
             * aren't interested.
             */
            if (patterns[i].type != DEV_MATCH_DEVICE) {
                  if ((patterns[i].type == DEV_MATCH_PERIPH)
                   && ((retval & DM_RET_ACTION_MASK) == DM_RET_NONE))
                        retval |= DM_RET_DESCEND;
                  continue;
            }

            cur_pattern = &patterns[i].pattern.device_pattern;

            /*
             * If they want to match any device node, we give them any
             * device node.
             */
            if (cur_pattern->flags == DEV_MATCH_ANY) {
                  /* set the copy flag */
                  retval |= DM_RET_COPY;

                  
                  /*
                   * If we've already decided on an action, go ahead
                   * and return.
                   */
                  if ((retval & DM_RET_ACTION_MASK) != DM_RET_NONE)
                        return(retval);
            }

            /*
             * Not sure why someone would do this...
             */
            if (cur_pattern->flags == DEV_MATCH_NONE)
                  continue;

            if (((cur_pattern->flags & DEV_MATCH_PATH) != 0)
             && (cur_pattern->path_id != device->target->bus->path_id))
                  continue;

            if (((cur_pattern->flags & DEV_MATCH_TARGET) != 0)
             && (cur_pattern->target_id != device->target->target_id))
                  continue;

            if (((cur_pattern->flags & DEV_MATCH_LUN) != 0)
             && (cur_pattern->target_lun != device->lun_id))
                  continue;

            if (((cur_pattern->flags & DEV_MATCH_INQUIRY) != 0)
             && (cam_quirkmatch((caddr_t)&device->inq_data,
                            (caddr_t)&cur_pattern->inq_pat,
                            1, sizeof(cur_pattern->inq_pat),
                            scsi_static_inquiry_match) == NULL))
                  continue;

            /*
             * If we get to this point, the user definitely wants 
             * information on this device.  So tell the caller to copy
             * the data out.
             */
            retval |= DM_RET_COPY;

            /*
             * If the return action has been set to descend, then we
             * know that we've already seen a peripheral matching
             * expression, therefore we need to further descend the tree.
             * This won't change by continuing around the loop, so we
             * go ahead and return.  If we haven't seen a peripheral
             * matching expression, we keep going around the loop until
             * we exhaust the matching expressions.  We'll set the stop
             * flag once we fall out of the loop.
             */
            if ((retval & DM_RET_ACTION_MASK) == DM_RET_DESCEND)
                  return(retval);
      }

      /*
       * If the return action hasn't been set to descend yet, that means
       * we haven't seen any peripheral matching patterns.  So tell the
       * caller to stop descending the tree -- the user doesn't want to
       * match against lower level tree elements.
       */
      if ((retval & DM_RET_ACTION_MASK) == DM_RET_NONE)
            retval |= DM_RET_STOP;

      return(retval);
}

/*
 * Match a single peripheral against any number of match patterns.
 */
static dev_match_ret
xptperiphmatch(struct dev_match_pattern *patterns, u_int num_patterns,
             struct cam_periph *periph)
{
      dev_match_ret retval;
      int i;

      /*
       * If we aren't given something to match against, that's an error.
       */
      if (periph == NULL)
            return(DM_RET_ERROR);

      /*
       * If there are no match entries, then this peripheral matches no
       * matter what.
       */
      if ((patterns == NULL) || (num_patterns == 0))
            return(DM_RET_STOP | DM_RET_COPY);

      /*
       * There aren't any nodes below a peripheral node, so there's no
       * reason to descend the tree any further.
       */
      retval = DM_RET_STOP;

      for (i = 0; i < num_patterns; i++) {
            struct periph_match_pattern *cur_pattern;

            /*
             * If the pattern in question isn't for a peripheral, we
             * aren't interested.
             */
            if (patterns[i].type != DEV_MATCH_PERIPH)
                  continue;

            cur_pattern = &patterns[i].pattern.periph_pattern;

            /*
             * If they want to match on anything, then we will do so.
             */
            if (cur_pattern->flags == PERIPH_MATCH_ANY) {
                  /* set the copy flag */
                  retval |= DM_RET_COPY;

                  /*
                   * We've already set the return action to stop,
                   * since there are no nodes below peripherals in
                   * the tree.
                   */
                  return(retval);
            }

            /*
             * Not sure why someone would do this...
             */
            if (cur_pattern->flags == PERIPH_MATCH_NONE)
                  continue;

            if (((cur_pattern->flags & PERIPH_MATCH_PATH) != 0)
             && (cur_pattern->path_id != periph->path->bus->path_id))
                  continue;

            /*
             * For the target and lun id's, we have to make sure the
             * target and lun pointers aren't NULL.  The xpt peripheral
             * has a wildcard target and device.
             */
            if (((cur_pattern->flags & PERIPH_MATCH_TARGET) != 0)
             && ((periph->path->target == NULL)
             ||(cur_pattern->target_id != periph->path->target->target_id)))
                  continue;

            if (((cur_pattern->flags & PERIPH_MATCH_LUN) != 0)
             && ((periph->path->device == NULL)
             || (cur_pattern->target_lun != periph->path->device->lun_id)))
                  continue;

            if (((cur_pattern->flags & PERIPH_MATCH_UNIT) != 0)
             && (cur_pattern->unit_number != periph->unit_number))
                  continue;

            if (((cur_pattern->flags & PERIPH_MATCH_NAME) != 0)
             && (strncmp(cur_pattern->periph_name, periph->periph_name,
                       DEV_IDLEN) != 0))
                  continue;

            /*
             * If we get to this point, the user definitely wants 
             * information on this peripheral.  So tell the caller to
             * copy the data out.
             */
            retval |= DM_RET_COPY;

            /*
             * The return action has already been set to stop, since
             * peripherals don't have any nodes below them in the EDT.
             */
            return(retval);
      }

      /*
       * If we get to this point, the peripheral that was passed in
       * doesn't match any of the patterns.
       */
      return(retval);
}

static int
xptedtbusfunc(struct cam_eb *bus, void *arg)
{
      struct ccb_dev_match *cdm;
      dev_match_ret retval;

      cdm = (struct ccb_dev_match *)arg;

      /*
       * If our position is for something deeper in the tree, that means
       * that we've already seen this node.  So, we keep going down.
       */
      if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
       && (cdm->pos.cookie.bus == bus)
       && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
       && (cdm->pos.cookie.target != NULL))
            retval = DM_RET_DESCEND;
      else
            retval = xptbusmatch(cdm->patterns, cdm->num_patterns, bus);

      /*
       * If we got an error, bail out of the search.
       */
      if ((retval & DM_RET_ACTION_MASK) == DM_RET_ERROR) {
            cdm->status = CAM_DEV_MATCH_ERROR;
            return(0);
      }

      /*
       * If the copy flag is set, copy this bus out.
       */
      if (retval & DM_RET_COPY) {
            int spaceleft, j;

            spaceleft = cdm->match_buf_len - (cdm->num_matches *
                  sizeof(struct dev_match_result));

            /*
             * If we don't have enough space to put in another
             * match result, save our position and tell the
             * user there are more devices to check.
             */
            if (spaceleft < sizeof(struct dev_match_result)) {
                  bzero(&cdm->pos, sizeof(cdm->pos));
                  cdm->pos.position_type = 
                        CAM_DEV_POS_EDT | CAM_DEV_POS_BUS;

                  cdm->pos.cookie.bus = bus;
                  cdm->pos.generations[CAM_BUS_GENERATION]=
                        bus_generation;
                  cdm->status = CAM_DEV_MATCH_MORE;
                  return(0);
            }
            j = cdm->num_matches;
            cdm->num_matches++;
            cdm->matches[j].type = DEV_MATCH_BUS;
            cdm->matches[j].result.bus_result.path_id = bus->path_id;
            cdm->matches[j].result.bus_result.bus_id = bus->sim->bus_id;
            cdm->matches[j].result.bus_result.unit_number =
                  bus->sim->unit_number;
            strncpy(cdm->matches[j].result.bus_result.dev_name,
                  bus->sim->sim_name, DEV_IDLEN);
      }

      /*
       * If the user is only interested in busses, there's no
       * reason to descend to the next level in the tree.
       */
      if ((retval & DM_RET_ACTION_MASK) == DM_RET_STOP)
            return(1);

      /*
       * If there is a target generation recorded, check it to
       * make sure the target list hasn't changed.
       */
      if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
       && (bus == cdm->pos.cookie.bus)
       && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
       && (cdm->pos.generations[CAM_TARGET_GENERATION] != 0)
       && (cdm->pos.generations[CAM_TARGET_GENERATION] !=
           bus->generation)) {
            cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
            return(0);
      }

      if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
       && (cdm->pos.cookie.bus == bus)
       && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
       && (cdm->pos.cookie.target != NULL))
            return(xpttargettraverse(bus,
                              (struct cam_et *)cdm->pos.cookie.target,
                               xptedttargetfunc, arg));
      else
            return(xpttargettraverse(bus, NULL, xptedttargetfunc, arg));
}

static int
xptedttargetfunc(struct cam_et *target, void *arg)
{
      struct ccb_dev_match *cdm;

      cdm = (struct ccb_dev_match *)arg;

      /*
       * If there is a device list generation recorded, check it to
       * make sure the device list hasn't changed.
       */
      if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
       && (cdm->pos.cookie.bus == target->bus)
       && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
       && (cdm->pos.cookie.target == target)
       && (cdm->pos.position_type & CAM_DEV_POS_DEVICE)
       && (cdm->pos.generations[CAM_DEV_GENERATION] != 0)
       && (cdm->pos.generations[CAM_DEV_GENERATION] !=
           target->generation)) {
            cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
            return(0);
      }

      if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
       && (cdm->pos.cookie.bus == target->bus)
       && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
       && (cdm->pos.cookie.target == target)
       && (cdm->pos.position_type & CAM_DEV_POS_DEVICE)
       && (cdm->pos.cookie.device != NULL))
            return(xptdevicetraverse(target,
                              (struct cam_ed *)cdm->pos.cookie.device,
                               xptedtdevicefunc, arg));
      else
            return(xptdevicetraverse(target, NULL, xptedtdevicefunc, arg));
}

static int
xptedtdevicefunc(struct cam_ed *device, void *arg)
{

      struct ccb_dev_match *cdm;
      dev_match_ret retval;

      cdm = (struct ccb_dev_match *)arg;

      /*
       * If our position is for something deeper in the tree, that means
       * that we've already seen this node.  So, we keep going down.
       */
      if ((cdm->pos.position_type & CAM_DEV_POS_DEVICE)
       && (cdm->pos.cookie.device == device)
       && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
       && (cdm->pos.cookie.periph != NULL))
            retval = DM_RET_DESCEND;
      else
            retval = xptdevicematch(cdm->patterns, cdm->num_patterns,
                              device);

      if ((retval & DM_RET_ACTION_MASK) == DM_RET_ERROR) {
            cdm->status = CAM_DEV_MATCH_ERROR;
            return(0);
      }

      /*
       * If the copy flag is set, copy this device out.
       */
      if (retval & DM_RET_COPY) {
            int spaceleft, j;

            spaceleft = cdm->match_buf_len - (cdm->num_matches *
                  sizeof(struct dev_match_result));

            /*
             * If we don't have enough space to put in another
             * match result, save our position and tell the
             * user there are more devices to check.
             */
            if (spaceleft < sizeof(struct dev_match_result)) {
                  bzero(&cdm->pos, sizeof(cdm->pos));
                  cdm->pos.position_type = 
                        CAM_DEV_POS_EDT | CAM_DEV_POS_BUS |
                        CAM_DEV_POS_TARGET | CAM_DEV_POS_DEVICE;

                  cdm->pos.cookie.bus = device->target->bus;
                  cdm->pos.generations[CAM_BUS_GENERATION]=
                        bus_generation;
                  cdm->pos.cookie.target = device->target;
                  cdm->pos.generations[CAM_TARGET_GENERATION] =
                        device->target->bus->generation;
                  cdm->pos.cookie.device = device;
                  cdm->pos.generations[CAM_DEV_GENERATION] = 
                        device->target->generation;
                  cdm->status = CAM_DEV_MATCH_MORE;
                  return(0);
            }
            j = cdm->num_matches;
            cdm->num_matches++;
            cdm->matches[j].type = DEV_MATCH_DEVICE;
            cdm->matches[j].result.device_result.path_id =
                  device->target->bus->path_id;
            cdm->matches[j].result.device_result.target_id =
                  device->target->target_id;
            cdm->matches[j].result.device_result.target_lun =
                  device->lun_id;
            bcopy(&device->inq_data,
                  &cdm->matches[j].result.device_result.inq_data,
                  sizeof(struct scsi_inquiry_data));

            /* Let the user know whether this device is unconfigured */
            if (device->flags & CAM_DEV_UNCONFIGURED)
                  cdm->matches[j].result.device_result.flags =
                        DEV_RESULT_UNCONFIGURED;
            else
                  cdm->matches[j].result.device_result.flags =
                        DEV_RESULT_NOFLAG;
      }

      /*
       * If the user isn't interested in peripherals, don't descend
       * the tree any further.
       */
      if ((retval & DM_RET_ACTION_MASK) == DM_RET_STOP)
            return(1);

      /*
       * If there is a peripheral list generation recorded, make sure
       * it hasn't changed.
       */
      if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
       && (device->target->bus == cdm->pos.cookie.bus)
       && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
       && (device->target == cdm->pos.cookie.target)
       && (cdm->pos.position_type & CAM_DEV_POS_DEVICE)
       && (device == cdm->pos.cookie.device)
       && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
       && (cdm->pos.generations[CAM_PERIPH_GENERATION] != 0)
       && (cdm->pos.generations[CAM_PERIPH_GENERATION] !=
           device->generation)){
            cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
            return(0);
      }

      if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
       && (cdm->pos.cookie.bus == device->target->bus)
       && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
       && (cdm->pos.cookie.target == device->target)
       && (cdm->pos.position_type & CAM_DEV_POS_DEVICE)
       && (cdm->pos.cookie.device == device)
       && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
       && (cdm->pos.cookie.periph != NULL))
            return(xptperiphtraverse(device,
                        (struct cam_periph *)cdm->pos.cookie.periph,
                        xptedtperiphfunc, arg));
      else
            return(xptperiphtraverse(device, NULL, xptedtperiphfunc, arg));
}

static int
xptedtperiphfunc(struct cam_periph *periph, void *arg)
{
      struct ccb_dev_match *cdm;
      dev_match_ret retval;

      cdm = (struct ccb_dev_match *)arg;

      retval = xptperiphmatch(cdm->patterns, cdm->num_patterns, periph);

      if ((retval & DM_RET_ACTION_MASK) == DM_RET_ERROR) {
            cdm->status = CAM_DEV_MATCH_ERROR;
            return(0);
      }

      /*
       * If the copy flag is set, copy this peripheral out.
       */
      if (retval & DM_RET_COPY) {
            int spaceleft, j;

            spaceleft = cdm->match_buf_len - (cdm->num_matches *
                  sizeof(struct dev_match_result));

            /*
             * If we don't have enough space to put in another
             * match result, save our position and tell the
             * user there are more devices to check.
             */
            if (spaceleft < sizeof(struct dev_match_result)) {
                  bzero(&cdm->pos, sizeof(cdm->pos));
                  cdm->pos.position_type = 
                        CAM_DEV_POS_EDT | CAM_DEV_POS_BUS |
                        CAM_DEV_POS_TARGET | CAM_DEV_POS_DEVICE |
                        CAM_DEV_POS_PERIPH;

                  cdm->pos.cookie.bus = periph->path->bus;
                  cdm->pos.generations[CAM_BUS_GENERATION]=
                        bus_generation;
                  cdm->pos.cookie.target = periph->path->target;
                  cdm->pos.generations[CAM_TARGET_GENERATION] =
                        periph->path->bus->generation;
                  cdm->pos.cookie.device = periph->path->device;
                  cdm->pos.generations[CAM_DEV_GENERATION] = 
                        periph->path->target->generation;
                  cdm->pos.cookie.periph = periph;
                  cdm->pos.generations[CAM_PERIPH_GENERATION] =
                        periph->path->device->generation;
                  cdm->status = CAM_DEV_MATCH_MORE;
                  return(0);
            }

            j = cdm->num_matches;
            cdm->num_matches++;
            cdm->matches[j].type = DEV_MATCH_PERIPH;
            cdm->matches[j].result.periph_result.path_id =
                  periph->path->bus->path_id;
            cdm->matches[j].result.periph_result.target_id =
                  periph->path->target->target_id;
            cdm->matches[j].result.periph_result.target_lun =
                  periph->path->device->lun_id;
            cdm->matches[j].result.periph_result.unit_number =
                  periph->unit_number;
            strncpy(cdm->matches[j].result.periph_result.periph_name,
                  periph->periph_name, DEV_IDLEN);
      }

      return(1);
}

static int
xptedtmatch(struct ccb_dev_match *cdm)
{
      int ret;

      cdm->num_matches = 0;

      /*
       * Check the bus list generation.  If it has changed, the user
       * needs to reset everything and start over.
       */
      if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
       && (cdm->pos.generations[CAM_BUS_GENERATION] != 0)
       && (cdm->pos.generations[CAM_BUS_GENERATION] != bus_generation)) {
            cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
            return(0);
      }

      if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
       && (cdm->pos.cookie.bus != NULL))
            ret = xptbustraverse((struct cam_eb *)cdm->pos.cookie.bus,
                             xptedtbusfunc, cdm);
      else
            ret = xptbustraverse(NULL, xptedtbusfunc, cdm);

      /*
       * If we get back 0, that means that we had to stop before fully
       * traversing the EDT.  It also means that one of the subroutines
       * has set the status field to the proper value.  If we get back 1,
       * we've fully traversed the EDT and copied out any matching entries.
       */
      if (ret == 1)
            cdm->status = CAM_DEV_MATCH_LAST;

      return(ret);
}

static int
xptplistpdrvfunc(struct periph_driver **pdrv, void *arg)
{
      struct ccb_dev_match *cdm;

      cdm = (struct ccb_dev_match *)arg;

      if ((cdm->pos.position_type & CAM_DEV_POS_PDPTR)
       && (cdm->pos.cookie.pdrv == pdrv)
       && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
       && (cdm->pos.generations[CAM_PERIPH_GENERATION] != 0)
       && (cdm->pos.generations[CAM_PERIPH_GENERATION] !=
           (*pdrv)->generation)) {
            cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
            return(0);
      }

      if ((cdm->pos.position_type & CAM_DEV_POS_PDPTR)
       && (cdm->pos.cookie.pdrv == pdrv)
       && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
       && (cdm->pos.cookie.periph != NULL))
            return(xptpdperiphtraverse(pdrv,
                        (struct cam_periph *)cdm->pos.cookie.periph,
                        xptplistperiphfunc, arg));
      else
            return(xptpdperiphtraverse(pdrv, NULL,xptplistperiphfunc, arg));
}

static int
xptplistperiphfunc(struct cam_periph *periph, void *arg)
{
      struct ccb_dev_match *cdm;
      dev_match_ret retval;

      cdm = (struct ccb_dev_match *)arg;

      retval = xptperiphmatch(cdm->patterns, cdm->num_patterns, periph);

      if ((retval & DM_RET_ACTION_MASK) == DM_RET_ERROR) {
            cdm->status = CAM_DEV_MATCH_ERROR;
            return(0);
      }

      /*
       * If the copy flag is set, copy this peripheral out.
       */
      if (retval & DM_RET_COPY) {
            int spaceleft, j;

            spaceleft = cdm->match_buf_len - (cdm->num_matches *
                  sizeof(struct dev_match_result));

            /*
             * If we don't have enough space to put in another
             * match result, save our position and tell the
             * user there are more devices to check.
             */
            if (spaceleft < sizeof(struct dev_match_result)) {
                  struct periph_driver **pdrv;

                  pdrv = NULL;
                  bzero(&cdm->pos, sizeof(cdm->pos));
                  cdm->pos.position_type = 
                        CAM_DEV_POS_PDRV | CAM_DEV_POS_PDPTR |
                        CAM_DEV_POS_PERIPH;

                  /*
                   * This may look a bit non-sensical, but it is
                   * actually quite logical.  There are very few
                   * peripheral drivers, and bloating every peripheral
                   * structure with a pointer back to its parent
                   * peripheral driver linker set entry would cost
                   * more in the long run than doing this quick lookup.
                   */
                  for (pdrv = periph_drivers; *pdrv != NULL; pdrv++) {
                        if (strcmp((*pdrv)->driver_name,
                            periph->periph_name) == 0)
                              break;
                  }

                  if (*pdrv == NULL) {
                        cdm->status = CAM_DEV_MATCH_ERROR;
                        return(0);
                  }

                  cdm->pos.cookie.pdrv = pdrv;
                  /*
                   * The periph generation slot does double duty, as
                   * does the periph pointer slot.  They are used for
                   * both edt and pdrv lookups and positioning.
                   */
                  cdm->pos.cookie.periph = periph;
                  cdm->pos.generations[CAM_PERIPH_GENERATION] =
                        (*pdrv)->generation;
                  cdm->status = CAM_DEV_MATCH_MORE;
                  return(0);
            }

            j = cdm->num_matches;
            cdm->num_matches++;
            cdm->matches[j].type = DEV_MATCH_PERIPH;
            cdm->matches[j].result.periph_result.path_id =
                  periph->path->bus->path_id;

            /*
             * The transport layer peripheral doesn't have a target or
             * lun.
             */
            if (periph->path->target)
                  cdm->matches[j].result.periph_result.target_id =
                        periph->path->target->target_id;
            else
                  cdm->matches[j].result.periph_result.target_id = -1;

            if (periph->path->device)
                  cdm->matches[j].result.periph_result.target_lun =
                        periph->path->device->lun_id;
            else
                  cdm->matches[j].result.periph_result.target_lun = -1;

            cdm->matches[j].result.periph_result.unit_number =
                  periph->unit_number;
            strncpy(cdm->matches[j].result.periph_result.periph_name,
                  periph->periph_name, DEV_IDLEN);
      }

      return(1);
}

static int
xptperiphlistmatch(struct ccb_dev_match *cdm)
{
      int ret;

      cdm->num_matches = 0;

      /*
       * At this point in the edt traversal function, we check the bus
       * list generation to make sure that no busses have been added or
       * removed since the user last sent a XPT_DEV_MATCH ccb through.
       * For the peripheral driver list traversal function, however, we
       * don't have to worry about new peripheral driver types coming or
       * going; they're in a linker set, and therefore can't change
       * without a recompile.
       */

      if ((cdm->pos.position_type & CAM_DEV_POS_PDPTR)
       && (cdm->pos.cookie.pdrv != NULL))
            ret = xptpdrvtraverse(
                        (struct periph_driver **)cdm->pos.cookie.pdrv,
                        xptplistpdrvfunc, cdm);
      else
            ret = xptpdrvtraverse(NULL, xptplistpdrvfunc, cdm);

      /*
       * If we get back 0, that means that we had to stop before fully
       * traversing the peripheral driver tree.  It also means that one of
       * the subroutines has set the status field to the proper value.  If
       * we get back 1, we've fully traversed the EDT and copied out any
       * matching entries.
       */
      if (ret == 1)
            cdm->status = CAM_DEV_MATCH_LAST;

      return(ret);
}

static int
xptbustraverse(struct cam_eb *start_bus, xpt_busfunc_t *tr_func, void *arg)
{
      struct cam_eb *bus, *next_bus;
      int retval;

      retval = 1;

      for (bus = (start_bus ? start_bus : TAILQ_FIRST(&xpt_busses));
           bus != NULL;
           bus = next_bus) {
            next_bus = TAILQ_NEXT(bus, links);

            retval = tr_func(bus, arg);
            if (retval == 0)
                  return(retval);
      }

      return(retval);
}

static int
xpttargettraverse(struct cam_eb *bus, struct cam_et *start_target,
              xpt_targetfunc_t *tr_func, void *arg)
{
      struct cam_et *target, *next_target;
      int retval;

      retval = 1;
      for (target = (start_target ? start_target :
                   TAILQ_FIRST(&bus->et_entries));
           target != NULL; target = next_target) {

            next_target = TAILQ_NEXT(target, links);

            retval = tr_func(target, arg);

            if (retval == 0)
                  return(retval);
      }

      return(retval);
}

static int
xptdevicetraverse(struct cam_et *target, struct cam_ed *start_device,
              xpt_devicefunc_t *tr_func, void *arg)
{
      struct cam_ed *device, *next_device;
      int retval;

      retval = 1;
      for (device = (start_device ? start_device :
                   TAILQ_FIRST(&target->ed_entries));
           device != NULL;
           device = next_device) {

            next_device = TAILQ_NEXT(device, links);

            retval = tr_func(device, arg);

            if (retval == 0)
                  return(retval);
      }

      return(retval);
}

static int
xptperiphtraverse(struct cam_ed *device, struct cam_periph *start_periph,
              xpt_periphfunc_t *tr_func, void *arg)
{
      struct cam_periph *periph, *next_periph;
      int retval;

      retval = 1;

      for (periph = (start_periph ? start_periph :
                   SLIST_FIRST(&device->periphs));
           periph != NULL;
           periph = next_periph) {

            next_periph = SLIST_NEXT(periph, periph_links);

            retval = tr_func(periph, arg);
            if (retval == 0)
                  return(retval);
      }

      return(retval);
}

static int
xptpdrvtraverse(struct periph_driver **start_pdrv,
            xpt_pdrvfunc_t *tr_func, void *arg)
{
      struct periph_driver **pdrv;
      int retval;

      retval = 1;

      /*
       * We don't traverse the peripheral driver list like we do the
       * other lists, because it is a linker set, and therefore cannot be
       * changed during runtime.  If the peripheral driver list is ever
       * re-done to be something other than a linker set (i.e. it can
       * change while the system is running), the list traversal should
       * be modified to work like the other traversal functions.
       */
      for (pdrv = (start_pdrv ? start_pdrv : periph_drivers);
           *pdrv != NULL; pdrv++) {
            retval = tr_func(pdrv, arg);

            if (retval == 0)
                  return(retval);
      }

      return(retval);
}

static int
xptpdperiphtraverse(struct periph_driver **pdrv,
                struct cam_periph *start_periph,
                xpt_periphfunc_t *tr_func, void *arg)
{
      struct cam_periph *periph, *next_periph;
      int retval;

      retval = 1;

      for (periph = (start_periph ? start_periph :
           TAILQ_FIRST(&(*pdrv)->units)); periph != NULL;
           periph = next_periph) {

            next_periph = TAILQ_NEXT(periph, unit_links);

            retval = tr_func(periph, arg);
            if (retval == 0)
                  return(retval);
      }
      return(retval);
}

static int
xptdefbusfunc(struct cam_eb *bus, void *arg)
{
      struct xpt_traverse_config *tr_config;

      tr_config = (struct xpt_traverse_config *)arg;

      if (tr_config->depth == XPT_DEPTH_BUS) {
            xpt_busfunc_t *tr_func;

            tr_func = (xpt_busfunc_t *)tr_config->tr_func;

            return(tr_func(bus, tr_config->tr_arg));
      } else
            return(xpttargettraverse(bus, NULL, xptdeftargetfunc, arg));
}

static int
xptdeftargetfunc(struct cam_et *target, void *arg)
{
      struct xpt_traverse_config *tr_config;

      tr_config = (struct xpt_traverse_config *)arg;

      if (tr_config->depth == XPT_DEPTH_TARGET) {
            xpt_targetfunc_t *tr_func;

            tr_func = (xpt_targetfunc_t *)tr_config->tr_func;

            return(tr_func(target, tr_config->tr_arg));
      } else
            return(xptdevicetraverse(target, NULL, xptdefdevicefunc, arg));
}

static int
xptdefdevicefunc(struct cam_ed *device, void *arg)
{
      struct xpt_traverse_config *tr_config;

      tr_config = (struct xpt_traverse_config *)arg;

      if (tr_config->depth == XPT_DEPTH_DEVICE) {
            xpt_devicefunc_t *tr_func;

            tr_func = (xpt_devicefunc_t *)tr_config->tr_func;

            return(tr_func(device, tr_config->tr_arg));
      } else
            return(xptperiphtraverse(device, NULL, xptdefperiphfunc, arg));
}

static int
xptdefperiphfunc(struct cam_periph *periph, void *arg)
{
      struct xpt_traverse_config *tr_config;
      xpt_periphfunc_t *tr_func;

      tr_config = (struct xpt_traverse_config *)arg;

      tr_func = (xpt_periphfunc_t *)tr_config->tr_func;

      /*
       * Unlike the other default functions, we don't check for depth
       * here.  The peripheral driver level is the last level in the EDT,
       * so if we're here, we should execute the function in question.
       */
      return(tr_func(periph, tr_config->tr_arg));
}

/*
 * Execute the given function for every bus in the EDT.
 */
static int
xpt_for_all_busses(xpt_busfunc_t *tr_func, void *arg)
{
      struct xpt_traverse_config tr_config;

      tr_config.depth = XPT_DEPTH_BUS;
      tr_config.tr_func = tr_func;
      tr_config.tr_arg = arg;

      return(xptbustraverse(NULL, xptdefbusfunc, &tr_config));
}

#ifdef notusedyet
/*
 * Execute the given function for every target in the EDT.
 */
static int
xpt_for_all_targets(xpt_targetfunc_t *tr_func, void *arg)
{
      struct xpt_traverse_config tr_config;

      tr_config.depth = XPT_DEPTH_TARGET;
      tr_config.tr_func = tr_func;
      tr_config.tr_arg = arg;

      return(xptbustraverse(NULL, xptdefbusfunc, &tr_config));
}
#endif /* notusedyet */

/*
 * Execute the given function for every device in the EDT.
 */
static int
xpt_for_all_devices(xpt_devicefunc_t *tr_func, void *arg)
{
      struct xpt_traverse_config tr_config;

      tr_config.depth = XPT_DEPTH_DEVICE;
      tr_config.tr_func = tr_func;
      tr_config.tr_arg = arg;

      return(xptbustraverse(NULL, xptdefbusfunc, &tr_config));
}

#ifdef notusedyet
/*
 * Execute the given function for every peripheral in the EDT.
 */
static int
xpt_for_all_periphs(xpt_periphfunc_t *tr_func, void *arg)
{
      struct xpt_traverse_config tr_config;

      tr_config.depth = XPT_DEPTH_PERIPH;
      tr_config.tr_func = tr_func;
      tr_config.tr_arg = arg;

      return(xptbustraverse(NULL, xptdefbusfunc, &tr_config));
}
#endif /* notusedyet */

static int
xptsetasyncfunc(struct cam_ed *device, void *arg)
{
      struct cam_path path;
      struct ccb_getdev cgd;
      struct async_node *cur_entry;

      cur_entry = (struct async_node *)arg;

      /*
       * Don't report unconfigured devices (Wildcard devs,
       * devices only for target mode, device instances
       * that have been invalidated but are waiting for
       * their last reference count to be released).
       */
      if ((device->flags & CAM_DEV_UNCONFIGURED) != 0)
            return (1);

      xpt_compile_path(&path,
                   NULL,
                   device->target->bus->path_id,
                   device->target->target_id,
                   device->lun_id);
      xpt_setup_ccb(&cgd.ccb_h, &path, /*priority*/1);
      cgd.ccb_h.func_code = XPT_GDEV_TYPE;
      xpt_action((union ccb *)&cgd);
      cur_entry->callback(cur_entry->callback_arg,
                      AC_FOUND_DEVICE,
                      &path, &cgd);
      xpt_release_path(&path);

      return(1);
}

static int
xptsetasyncbusfunc(struct cam_eb *bus, void *arg)
{
      struct cam_path path;
      struct ccb_pathinq cpi;
      struct async_node *cur_entry;

      cur_entry = (struct async_node *)arg;

      xpt_compile_path(&path, /*periph*/NULL,
                   bus->sim->path_id,
                   CAM_TARGET_WILDCARD,
                   CAM_LUN_WILDCARD);
      xpt_setup_ccb(&cpi.ccb_h, &path, /*priority*/1);
      cpi.ccb_h.func_code = XPT_PATH_INQ;
      xpt_action((union ccb *)&cpi);
      cur_entry->callback(cur_entry->callback_arg,
                      AC_PATH_REGISTERED,
                      &path, &cpi);
      xpt_release_path(&path);

      return(1);
}

void
xpt_action(union ccb *start_ccb)
{
      int iopl;

      GIANT_REQUIRED;

      CAM_DEBUG(start_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("xpt_action\n"));

      start_ccb->ccb_h.status = CAM_REQ_INPROG;

      iopl = splsoftcam();
      switch (start_ccb->ccb_h.func_code) {
      case XPT_SCSI_IO:
      {
#ifdef CAM_NEW_TRAN_CODE
            struct cam_ed *device;
#endif /* CAM_NEW_TRAN_CODE */
#ifdef CAMDEBUG
            char cdb_str[(SCSI_MAX_CDBLEN * 3) + 1];
            struct cam_path *path;

            path = start_ccb->ccb_h.path;
#endif

            /*
             * For the sake of compatibility with SCSI-1
             * devices that may not understand the identify
             * message, we include lun information in the
             * second byte of all commands.  SCSI-1 specifies
             * that luns are a 3 bit value and reserves only 3
             * bits for lun information in the CDB.  Later
             * revisions of the SCSI spec allow for more than 8
             * luns, but have deprecated lun information in the
             * CDB.  So, if the lun won't fit, we must omit.
             *
             * Also be aware that during initial probing for devices,
             * the inquiry information is unknown but initialized to 0.
             * This means that this code will be exercised while probing
             * devices with an ANSI revision greater than 2.
             */
#ifdef CAM_NEW_TRAN_CODE
            device = start_ccb->ccb_h.path->device;
            if (device->protocol_version <= SCSI_REV_2
#else /* CAM_NEW_TRAN_CODE */
            if (SID_ANSI_REV(&start_ccb->ccb_h.path->device->inq_data) <= 2
#endif /* CAM_NEW_TRAN_CODE */
             && start_ccb->ccb_h.target_lun < 8
             && (start_ccb->ccb_h.flags & CAM_CDB_POINTER) == 0) {

                  start_ccb->csio.cdb_io.cdb_bytes[1] |=
                      start_ccb->ccb_h.target_lun << 5;
            }
            start_ccb->csio.scsi_status = SCSI_STATUS_OK;
            CAM_DEBUG(path, CAM_DEBUG_CDB,("%s. CDB: %s\n",
                    scsi_op_desc(start_ccb->csio.cdb_io.cdb_bytes[0],
                               &path->device->inq_data),
                    scsi_cdb_string(start_ccb->csio.cdb_io.cdb_bytes,
                                cdb_str, sizeof(cdb_str))));
      }
      /* FALLTHROUGH */
      case XPT_TARGET_IO:
      case XPT_CONT_TARGET_IO:
            start_ccb->csio.sense_resid = 0;
            start_ccb->csio.resid = 0;
            /* FALLTHROUGH */
      case XPT_RESET_DEV:
      case XPT_ENG_EXEC:
      {
            struct cam_path *path;
            struct cam_sim *sim;
            int s;
            int runq;

            path = start_ccb->ccb_h.path;
            s = splsoftcam();

            sim = path->bus->sim;
            if (SIM_DEAD(sim)) {
                  /* The SIM has gone; just execute the CCB directly. */
                  cam_ccbq_send_ccb(&path->device->ccbq, start_ccb);
                  (*(sim->sim_action))(sim, start_ccb);
                  splx(s);
                  break;
            }

            cam_ccbq_insert_ccb(&path->device->ccbq, start_ccb);
            if (path->device->qfrozen_cnt == 0)
                  runq = xpt_schedule_dev_sendq(path->bus, path->device);
            else
                  runq = 0;
            splx(s);
            if (runq != 0)
                  xpt_run_dev_sendq(path->bus);
            break;
      }
      case XPT_SET_TRAN_SETTINGS:
      {
            xpt_set_transfer_settings(&start_ccb->cts,
                                start_ccb->ccb_h.path->device,
                                /*async_update*/FALSE);
            break;
      }
      case XPT_CALC_GEOMETRY:
      {
            struct cam_sim *sim;

            /* Filter out garbage */
            if (start_ccb->ccg.block_size == 0
             || start_ccb->ccg.volume_size == 0) {
                  start_ccb->ccg.cylinders = 0;
                  start_ccb->ccg.heads = 0;
                  start_ccb->ccg.secs_per_track = 0;
                  start_ccb->ccb_h.status = CAM_REQ_CMP;
                  break;
            }
#ifdef PC98
            /*
             * In a PC-98 system, geometry translation depens on
             * the "real" device geometry obtained from mode page 4.
             * SCSI geometry translation is performed in the
             * initialization routine of the SCSI BIOS and the result
             * stored in host memory.  If the translation is available
             * in host memory, use it.  If not, rely on the default
             * translation the device driver performs.
             */
            if (scsi_da_bios_params(&start_ccb->ccg) != 0) {
                  start_ccb->ccb_h.status = CAM_REQ_CMP;
                  break;
            }
#endif
            sim = start_ccb->ccb_h.path->bus->sim;
            (*(sim->sim_action))(sim, start_ccb);
            break;
      }
      case XPT_ABORT:
      {
            union ccb* abort_ccb;
            int s;                        

            abort_ccb = start_ccb->cab.abort_ccb;
            if (XPT_FC_IS_DEV_QUEUED(abort_ccb)) {

                  if (abort_ccb->ccb_h.pinfo.index >= 0) {
                        struct cam_ccbq *ccbq;

                        ccbq = &abort_ccb->ccb_h.path->device->ccbq;
                        cam_ccbq_remove_ccb(ccbq, abort_ccb);
                        abort_ccb->ccb_h.status =
                            CAM_REQ_ABORTED|CAM_DEV_QFRZN;
                        xpt_freeze_devq(abort_ccb->ccb_h.path, 1);
                        s = splcam();
                        xpt_done(abort_ccb);
                        splx(s);
                        start_ccb->ccb_h.status = CAM_REQ_CMP;
                        break;
                  }
                  if (abort_ccb->ccb_h.pinfo.index == CAM_UNQUEUED_INDEX
                   && (abort_ccb->ccb_h.status & CAM_SIM_QUEUED) == 0) {
                        /*
                         * We've caught this ccb en route to
                         * the SIM.  Flag it for abort and the
                         * SIM will do so just before starting
                         * real work on the CCB.
                         */
                        abort_ccb->ccb_h.status =
                            CAM_REQ_ABORTED|CAM_DEV_QFRZN;
                        xpt_freeze_devq(abort_ccb->ccb_h.path, 1);
                        start_ccb->ccb_h.status = CAM_REQ_CMP;
                        break;
                  }
            } 
            if (XPT_FC_IS_QUEUED(abort_ccb)
             && (abort_ccb->ccb_h.pinfo.index == CAM_DONEQ_INDEX)) {
                  /*
                   * It's already completed but waiting
                   * for our SWI to get to it.
                   */
                  start_ccb->ccb_h.status = CAM_UA_ABORT;
                  break;
            }
            /*
             * If we weren't able to take care of the abort request
             * in the XPT, pass the request down to the SIM for processing.
             */
      }
      /* FALLTHROUGH */
      case XPT_ACCEPT_TARGET_IO:
      case XPT_EN_LUN:
      case XPT_IMMED_NOTIFY:
      case XPT_NOTIFY_ACK:
      case XPT_GET_TRAN_SETTINGS:
      case XPT_RESET_BUS:
      {
            struct cam_sim *sim;

            sim = start_ccb->ccb_h.path->bus->sim;
            (*(sim->sim_action))(sim, start_ccb);
            break;
      }
      case XPT_PATH_INQ:
      {
            struct cam_sim *sim;

            sim = start_ccb->ccb_h.path->bus->sim;
            (*(sim->sim_action))(sim, start_ccb);
            break;
      }
      case XPT_PATH_STATS:
            start_ccb->cpis.last_reset =
                  start_ccb->ccb_h.path->bus->last_reset;
            start_ccb->ccb_h.status = CAM_REQ_CMP;
            break;
      case XPT_GDEV_TYPE:
      {
            struct cam_ed *dev;
            int s;

            dev = start_ccb->ccb_h.path->device;
            s = splcam();
            if ((dev->flags & CAM_DEV_UNCONFIGURED) != 0) {
                  start_ccb->ccb_h.status = CAM_DEV_NOT_THERE;
            } else {
                  struct ccb_getdev *cgd;
                  struct cam_eb *bus;
                  struct cam_et *tar;

                  cgd = &start_ccb->cgd;
                  bus = cgd->ccb_h.path->bus;
                  tar = cgd->ccb_h.path->target;
                  cgd->inq_data = dev->inq_data;
                  cgd->ccb_h.status = CAM_REQ_CMP;
                  cgd->serial_num_len = dev->serial_num_len;
                  if ((dev->serial_num_len > 0)
                   && (dev->serial_num != NULL))
                        bcopy(dev->serial_num, cgd->serial_num,
                              dev->serial_num_len);
            }
            splx(s);
            break; 
      }
      case XPT_GDEV_STATS:
      {
            struct cam_ed *dev;
            int s;

            dev = start_ccb->ccb_h.path->device;
            s = splcam();
            if ((dev->flags & CAM_DEV_UNCONFIGURED) != 0) {
                  start_ccb->ccb_h.status = CAM_DEV_NOT_THERE;
            } else {
                  struct ccb_getdevstats *cgds;
                  struct cam_eb *bus;
                  struct cam_et *tar;

                  cgds = &start_ccb->cgds;
                  bus = cgds->ccb_h.path->bus;
                  tar = cgds->ccb_h.path->target;
                  cgds->dev_openings = dev->ccbq.dev_openings;
                  cgds->dev_active = dev->ccbq.dev_active;
                  cgds->devq_openings = dev->ccbq.devq_openings;
                  cgds->devq_queued = dev->ccbq.queue.entries;
                  cgds->held = dev->ccbq.held;
                  cgds->last_reset = tar->last_reset;
                  cgds->maxtags = dev->quirk->maxtags;
                  cgds->mintags = dev->quirk->mintags;
                  if (timevalcmp(&tar->last_reset, &bus->last_reset, <))
                        cgds->last_reset = bus->last_reset;
                  cgds->ccb_h.status = CAM_REQ_CMP;
            }
            splx(s);
            break;
      }
      case XPT_GDEVLIST:
      {
            struct cam_periph *nperiph;
            struct periph_list      *periph_head;
            struct ccb_getdevlist   *cgdl;
            u_int             i;
            int               s;
            struct cam_ed           *device;
            int               found;


            found = 0;

            /*
             * Don't want anyone mucking with our data.
             */
            s = splcam();
            device = start_ccb->ccb_h.path->device;
            periph_head = &device->periphs;
            cgdl = &start_ccb->cgdl;

            /*
             * Check and see if the list has changed since the user
             * last requested a list member.  If so, tell them that the
             * list has changed, and therefore they need to start over 
             * from the beginning.
             */
            if ((cgdl->index != 0) && 
                (cgdl->generation != device->generation)) {
                  cgdl->status = CAM_GDEVLIST_LIST_CHANGED;
                  splx(s);
                  break;
            }

            /*
             * Traverse the list of peripherals and attempt to find 
             * the requested peripheral.
             */
            for (nperiph = SLIST_FIRST(periph_head), i = 0;
                 (nperiph != NULL) && (i <= cgdl->index);
                 nperiph = SLIST_NEXT(nperiph, periph_links), i++) {
                  if (i == cgdl->index) {
                        strncpy(cgdl->periph_name,
                              nperiph->periph_name,
                              DEV_IDLEN);
                        cgdl->unit_number = nperiph->unit_number;
                        found = 1;
                  }
            }
            if (found == 0) {
                  cgdl->status = CAM_GDEVLIST_ERROR;
                  splx(s);
                  break;
            }

            if (nperiph == NULL)
                  cgdl->status = CAM_GDEVLIST_LAST_DEVICE;
            else
                  cgdl->status = CAM_GDEVLIST_MORE_DEVS;

            cgdl->index++;
            cgdl->generation = device->generation;

            splx(s);
            cgdl->ccb_h.status = CAM_REQ_CMP;
            break;
      }
      case XPT_DEV_MATCH:
      {
            int s;
            dev_pos_type position_type;
            struct ccb_dev_match *cdm;

            cdm = &start_ccb->cdm;

            /*
             * Prevent EDT changes while we traverse it.
             */
            s = splcam();
            /*
             * There are two ways of getting at information in the EDT.
             * The first way is via the primary EDT tree.  It starts
             * with a list of busses, then a list of targets on a bus,
             * then devices/luns on a target, and then peripherals on a
             * device/lun.  The "other" way is by the peripheral driver
             * lists.  The peripheral driver lists are organized by
             * peripheral driver.  (obviously)  So it makes sense to
             * use the peripheral driver list if the user is looking
             * for something like "da1", or all "da" devices.  If the
             * user is looking for something on a particular bus/target
             * or lun, it's generally better to go through the EDT tree.
             */

            if (cdm->pos.position_type != CAM_DEV_POS_NONE)
                  position_type = cdm->pos.position_type;
            else {
                  u_int i;

                  position_type = CAM_DEV_POS_NONE;

                  for (i = 0; i < cdm->num_patterns; i++) {
                        if ((cdm->patterns[i].type == DEV_MATCH_BUS)
                         ||(cdm->patterns[i].type == DEV_MATCH_DEVICE)){
                              position_type = CAM_DEV_POS_EDT;
                              break;
                        }
                  }

                  if (cdm->num_patterns == 0)
                        position_type = CAM_DEV_POS_EDT;
                  else if (position_type == CAM_DEV_POS_NONE)
                        position_type = CAM_DEV_POS_PDRV;
            }

            switch(position_type & CAM_DEV_POS_TYPEMASK) {
            case CAM_DEV_POS_EDT:
                  xptedtmatch(cdm);
                  break;
            case CAM_DEV_POS_PDRV:
                  xptperiphlistmatch(cdm);
                  break;
            default:
                  cdm->status = CAM_DEV_MATCH_ERROR;
                  break;
            }

            splx(s);

            if (cdm->status == CAM_DEV_MATCH_ERROR)
                  start_ccb->ccb_h.status = CAM_REQ_CMP_ERR;
            else
                  start_ccb->ccb_h.status = CAM_REQ_CMP;

            break;
      }
      case XPT_SASYNC_CB:
      {
            struct ccb_setasync *csa;
            struct async_node *cur_entry;
            struct async_list *async_head;
            u_int32_t added;
            int s;

            csa = &start_ccb->csa;
            added = csa->event_enable;
            async_head = &csa->ccb_h.path->device->asyncs;

            /*
             * If there is already an entry for us, simply
             * update it.
             */
            s = splcam();
            cur_entry = SLIST_FIRST(async_head);
            while (cur_entry != NULL) {
                  if ((cur_entry->callback_arg == csa->callback_arg)
                   && (cur_entry->callback == csa->callback))
                        break;
                  cur_entry = SLIST_NEXT(cur_entry, links);
            }

            if (cur_entry != NULL) {
                  /*
                   * If the request has no flags set,
                   * remove the entry.
                   */
                  added &= ~cur_entry->event_enable;
                  if (csa->event_enable == 0) {
                        SLIST_REMOVE(async_head, cur_entry,
                                   async_node, links);
                        csa->ccb_h.path->device->refcount--;
                        free(cur_entry, M_CAMXPT);
                  } else {
                        cur_entry->event_enable = csa->event_enable;
                  }
            } else {
                  cur_entry = malloc(sizeof(*cur_entry), M_CAMXPT,
                                 M_NOWAIT);
                  if (cur_entry == NULL) {
                        splx(s);
                        csa->ccb_h.status = CAM_RESRC_UNAVAIL;
                        break;
                  }
                  cur_entry->event_enable = csa->event_enable;
                  cur_entry->callback_arg = csa->callback_arg;
                  cur_entry->callback = csa->callback;
                  SLIST_INSERT_HEAD(async_head, cur_entry, links);
                  csa->ccb_h.path->device->refcount++;
            }

            if ((added & AC_FOUND_DEVICE) != 0) {
                  /*
                   * Get this peripheral up to date with all
                   * the currently existing devices.
                   */
                  xpt_for_all_devices(xptsetasyncfunc, cur_entry);
            }
            if ((added & AC_PATH_REGISTERED) != 0) {
                  /*
                   * Get this peripheral up to date with all
                   * the currently existing busses.
                   */
                  xpt_for_all_busses(xptsetasyncbusfunc, cur_entry);
            }
            splx(s);
            start_ccb->ccb_h.status = CAM_REQ_CMP;
            break;
      }
      case XPT_REL_SIMQ:
      {
            struct ccb_relsim *crs;
            struct cam_ed *dev;
            int s;

            crs = &start_ccb->crs;
            dev = crs->ccb_h.path->device;
            if (dev == NULL) {

                  crs->ccb_h.status = CAM_DEV_NOT_THERE;
                  break;
            }

            s = splcam();

            if ((crs->release_flags & RELSIM_ADJUST_OPENINGS) != 0) {

                  if (INQ_DATA_TQ_ENABLED(&dev->inq_data)) {
                        /* Don't ever go below one opening */
                        if (crs->openings > 0) {
                              xpt_dev_ccbq_resize(crs->ccb_h.path,
                                              crs->openings);

                              if (bootverbose) {
                                    xpt_print_path(crs->ccb_h.path);
                                    printf("tagged openings "
                                           "now %d\n",
                                           crs->openings);
                              }
                        }
                  }
            }

            if ((crs->release_flags & RELSIM_RELEASE_AFTER_TIMEOUT) != 0) {

                  if ((dev->flags & CAM_DEV_REL_TIMEOUT_PENDING) != 0) {

                        /*
                         * Just extend the old timeout and decrement
                         * the freeze count so that a single timeout
                         * is sufficient for releasing the queue.
                         */
                        start_ccb->ccb_h.flags &= ~CAM_DEV_QFREEZE;
                        untimeout(xpt_release_devq_timeout,
                                dev, dev->c_handle);
                  } else {

                        start_ccb->ccb_h.flags |= CAM_DEV_QFREEZE;
                  }

                  dev->c_handle =
                        timeout(xpt_release_devq_timeout,
                              dev,
                              (crs->release_timeout * hz) / 1000);

                  dev->flags |= CAM_DEV_REL_TIMEOUT_PENDING;

            }

            if ((crs->release_flags & RELSIM_RELEASE_AFTER_CMDCMPLT) != 0) {

                  if ((dev->flags & CAM_DEV_REL_ON_COMPLETE) != 0) {
                        /*
                         * Decrement the freeze count so that a single
                         * completion is still sufficient to unfreeze
                         * the queue.
                         */
                        start_ccb->ccb_h.flags &= ~CAM_DEV_QFREEZE;
                  } else {
                        
                        dev->flags |= CAM_DEV_REL_ON_COMPLETE;
                        start_ccb->ccb_h.flags |= CAM_DEV_QFREEZE;
                  }
            }

            if ((crs->release_flags & RELSIM_RELEASE_AFTER_QEMPTY) != 0) {

                  if ((dev->flags & CAM_DEV_REL_ON_QUEUE_EMPTY) != 0
                   || (dev->ccbq.dev_active == 0)) {

                        start_ccb->ccb_h.flags &= ~CAM_DEV_QFREEZE;
                  } else {
                        
                        dev->flags |= CAM_DEV_REL_ON_QUEUE_EMPTY;
                        start_ccb->ccb_h.flags |= CAM_DEV_QFREEZE;
                  }
            }
            splx(s);
            
            if ((start_ccb->ccb_h.flags & CAM_DEV_QFREEZE) == 0) {

                  xpt_release_devq(crs->ccb_h.path, /*count*/1,
                               /*run_queue*/TRUE);
            }
            start_ccb->crs.qfrozen_cnt = dev->qfrozen_cnt;
            start_ccb->ccb_h.status = CAM_REQ_CMP;
            break;
      }
      case XPT_SCAN_BUS:
            xpt_scan_bus(start_ccb->ccb_h.path->periph, start_ccb);
            break;
      case XPT_SCAN_LUN:
            xpt_scan_lun(start_ccb->ccb_h.path->periph,
                       start_ccb->ccb_h.path, start_ccb->crcn.flags,
                       start_ccb);
            break;
      case XPT_DEBUG: {
#ifdef CAMDEBUG
            int s;
            
            s = splcam();
#ifdef CAM_DEBUG_DELAY
            cam_debug_delay = CAM_DEBUG_DELAY;
#endif
            cam_dflags = start_ccb->cdbg.flags;
            if (cam_dpath != NULL) {
                  xpt_free_path(cam_dpath);
                  cam_dpath = NULL;
            }

            if (cam_dflags != CAM_DEBUG_NONE) {
                  if (xpt_create_path(&cam_dpath, xpt_periph,
                                  start_ccb->ccb_h.path_id,
                                  start_ccb->ccb_h.target_id,
                                  start_ccb->ccb_h.target_lun) !=
                                  CAM_REQ_CMP) {
                        start_ccb->ccb_h.status = CAM_RESRC_UNAVAIL;
                        cam_dflags = CAM_DEBUG_NONE;
                  } else {
                        start_ccb->ccb_h.status = CAM_REQ_CMP;
                        xpt_print_path(cam_dpath);
                        printf("debugging flags now %x\n", cam_dflags);
                  }
            } else {
                  cam_dpath = NULL;
                  start_ccb->ccb_h.status = CAM_REQ_CMP;
            }
            splx(s);
#else /* !CAMDEBUG */
            start_ccb->ccb_h.status = CAM_FUNC_NOTAVAIL;
#endif /* CAMDEBUG */
            break;
      }
      case XPT_NOOP:
            if ((start_ccb->ccb_h.flags & CAM_DEV_QFREEZE) != 0)
                  xpt_freeze_devq(start_ccb->ccb_h.path, 1);
            start_ccb->ccb_h.status = CAM_REQ_CMP;
            break;
      default:
      case XPT_SDEV_TYPE:
      case XPT_TERM_IO:
      case XPT_ENG_INQ:
            /* XXX Implement */
            start_ccb->ccb_h.status = CAM_PROVIDE_FAIL;
            break;
      }
      splx(iopl);
}

void
xpt_polled_action(union ccb *start_ccb)
{
      int     s;
      u_int32_t timeout;
      struct        cam_sim *sim;   
      struct        cam_devq *devq;
      struct        cam_ed *dev;

      GIANT_REQUIRED;

      timeout = start_ccb->ccb_h.timeout;
      sim = start_ccb->ccb_h.path->bus->sim;
      devq = sim->devq;
      dev = start_ccb->ccb_h.path->device;

      s = splcam();

      /*
       * Steal an opening so that no other queued requests
       * can get it before us while we simulate interrupts.
       */
      dev->ccbq.devq_openings--;
      dev->ccbq.dev_openings--;     
      
      while(((devq != NULL && devq->send_openings <= 0) ||
         dev->ccbq.dev_openings < 0) && (--timeout > 0)) {
            DELAY(1000);
            (*(sim->sim_poll))(sim);
            camisr(&cam_bioq);
      }
      
      dev->ccbq.devq_openings++;
      dev->ccbq.dev_openings++;
      
      if (timeout != 0) {
            xpt_action(start_ccb);
            while(--timeout > 0) {
                  (*(sim->sim_poll))(sim);
                  camisr(&cam_bioq);
                  if ((start_ccb->ccb_h.status  & CAM_STATUS_MASK)
                      != CAM_REQ_INPROG)
                        break;
                  DELAY(1000);
            }
            if (timeout == 0) {
                  /*
                   * XXX Is it worth adding a sim_timeout entry
                   * point so we can attempt recovery?  If
                   * this is only used for dumps, I don't think
                   * it is.
                   */
                  start_ccb->ccb_h.status = CAM_CMD_TIMEOUT;
            }
      } else {
            start_ccb->ccb_h.status = CAM_RESRC_UNAVAIL;
      }
      splx(s);
}
      
/*
 * Schedule a peripheral driver to receive a ccb when it's
 * target device has space for more transactions.
 */
void
xpt_schedule(struct cam_periph *perph, u_int32_t new_priority)
{
      struct cam_ed *device;
      union ccb *work_ccb;
      int s;
      int runq;

      GIANT_REQUIRED;

      CAM_DEBUG(perph->path, CAM_DEBUG_TRACE, ("xpt_schedule\n"));
      device = perph->path->device;
      s = splsoftcam();
      if (periph_is_queued(perph)) {
            /* Simply reorder based on new priority */
            CAM_DEBUG(perph->path, CAM_DEBUG_SUBTRACE,
                    ("   change priority to %d\n", new_priority));
            if (new_priority < perph->pinfo.priority) {
                  camq_change_priority(&device->drvq,
                                   perph->pinfo.index,
                                   new_priority);
            }
            runq = 0;
      } else if (SIM_DEAD(perph->path->bus->sim)) {
            /* The SIM is gone so just call periph_start directly. */
            work_ccb = xpt_get_ccb(perph->path->device);
            splx(s);
            if (work_ccb == NULL)
                  return; /* XXX */
            xpt_setup_ccb(&work_ccb->ccb_h, perph->path, new_priority);
            perph->pinfo.priority = new_priority;
            perph->periph_start(perph, work_ccb);
            return;
      } else {
            /* New entry on the queue */
            CAM_DEBUG(perph->path, CAM_DEBUG_SUBTRACE,
                    ("   added periph to queue\n"));
            perph->pinfo.priority = new_priority;
            perph->pinfo.generation = ++device->drvq.generation;
            camq_insert(&device->drvq, &perph->pinfo);
            runq = xpt_schedule_dev_allocq(perph->path->bus, device);
      }
      splx(s);
      if (runq != 0) {
            CAM_DEBUG(perph->path, CAM_DEBUG_SUBTRACE,
                    ("   calling xpt_run_devq\n"));
            xpt_run_dev_allocq(perph->path->bus);
      }
}


/*
 * Schedule a device to run on a given queue.
 * If the device was inserted as a new entry on the queue,
 * return 1 meaning the device queue should be run. If we
 * were already queued, implying someone else has already
 * started the queue, return 0 so the caller doesn't attempt
 * to run the queue.  Must be run at either splsoftcam
 * (or splcam since that encompases splsoftcam).
 */
static int
xpt_schedule_dev(struct camq *queue, cam_pinfo *pinfo,
             u_int32_t new_priority)
{
      int retval;
      u_int32_t old_priority;

      CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_schedule_dev\n"));

      old_priority = pinfo->priority;

      /*
       * Are we already queued?
       */
      if (pinfo->index != CAM_UNQUEUED_INDEX) {
            /* Simply reorder based on new priority */
            if (new_priority < old_priority) {
                  camq_change_priority(queue, pinfo->index,
                                   new_priority);
                  CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                              ("changed priority to %d\n",
                               new_priority));
            }
            retval = 0;
      } else {
            /* New entry on the queue */
            if (new_priority < old_priority)
                  pinfo->priority = new_priority;

            CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                        ("Inserting onto queue\n"));
            pinfo->generation = ++queue->generation;
            camq_insert(queue, pinfo);
            retval = 1;
      }
      return (retval);
}

static void
xpt_run_dev_allocq(struct cam_eb *bus)
{
      struct      cam_devq *devq;
      int   s;

      CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_run_dev_allocq\n"));
      devq = bus->sim->devq;

      CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                  ("   qfrozen_cnt == 0x%x, entries == %d, "
                   "openings == %d, active == %d\n",
                   devq->alloc_queue.qfrozen_cnt,
                   devq->alloc_queue.entries,
                   devq->alloc_openings,
                   devq->alloc_active));

      s = splsoftcam();
      devq->alloc_queue.qfrozen_cnt++;
      while ((devq->alloc_queue.entries > 0)
          && (devq->alloc_openings > 0)
          && (devq->alloc_queue.qfrozen_cnt <= 1)) {
            struct      cam_ed_qinfo *qinfo;
            struct      cam_ed *device;
            union ccb *work_ccb;
            struct      cam_periph *drv;
            struct      camq *drvq;
            
            qinfo = (struct cam_ed_qinfo *)camq_remove(&devq->alloc_queue,
                                             CAMQ_HEAD);
            device = qinfo->device;

            CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                        ("running device %p\n", device));

            drvq = &device->drvq;

#ifdef CAMDEBUG
            if (drvq->entries <= 0) {
                  panic("xpt_run_dev_allocq: "
                        "Device on queue without any work to do");
            }
#endif
            if ((work_ccb = xpt_get_ccb(device)) != NULL) {
                  devq->alloc_openings--;
                  devq->alloc_active++;
                  drv = (struct cam_periph*)camq_remove(drvq, CAMQ_HEAD);
                  splx(s);
                  xpt_setup_ccb(&work_ccb->ccb_h, drv->path,
                              drv->pinfo.priority);
                  CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                              ("calling periph start\n"));
                  drv->periph_start(drv, work_ccb);
            } else {
                  /*
                   * Malloc failure in alloc_ccb
                   */
                  /*
                   * XXX add us to a list to be run from free_ccb
                   * if we don't have any ccbs active on this
                   * device queue otherwise we may never get run
                   * again.
                   */
                  break;
            }
      
            /* Raise IPL for possible insertion and test at top of loop */
            s = splsoftcam();

            if (drvq->entries > 0) {
                  /* We have more work.  Attempt to reschedule */
                  xpt_schedule_dev_allocq(bus, device);
            }
      }
      devq->alloc_queue.qfrozen_cnt--;
      splx(s);
}

static void
xpt_run_dev_sendq(struct cam_eb *bus)
{
      struct      cam_devq *devq;
      int   s;

      CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_run_dev_sendq\n"));
      
      devq = bus->sim->devq;

      s = splcam();
      devq->send_queue.qfrozen_cnt++;
      splx(s);
      s = splsoftcam();
      while ((devq->send_queue.entries > 0)
          && (devq->send_openings > 0)) {
            struct      cam_ed_qinfo *qinfo;
            struct      cam_ed *device;
            union ccb *work_ccb;
            struct      cam_sim *sim;
            int   ospl;

            ospl = splcam();
            if (devq->send_queue.qfrozen_cnt > 1) {
                  splx(ospl);
                  break;
            }

            qinfo = (struct cam_ed_qinfo *)camq_remove(&devq->send_queue,
                                             CAMQ_HEAD);
            device = qinfo->device;

            /*
             * If the device has been "frozen", don't attempt
             * to run it.
             */
            if (device->qfrozen_cnt > 0) {
                  splx(ospl);
                  continue;
            }

            CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                        ("running device %p\n", device));

            work_ccb = cam_ccbq_peek_ccb(&device->ccbq, CAMQ_HEAD);
            if (work_ccb == NULL) {
                  printf("device on run queue with no ccbs???\n");
                  splx(ospl);
                  continue;
            }

            if ((work_ccb->ccb_h.flags & CAM_HIGH_POWER) != 0) {

                  if (num_highpower <= 0) {
                        /*
                         * We got a high power command, but we
                         * don't have any available slots.  Freeze
                         * the device queue until we have a slot
                         * available.
                         */
                        device->qfrozen_cnt++;
                        STAILQ_INSERT_TAIL(&highpowerq, 
                                       &work_ccb->ccb_h, 
                                       xpt_links.stqe);

                        splx(ospl);
                        continue;
                  } else {
                        /*
                         * Consume a high power slot while
                         * this ccb runs.
                         */
                        num_highpower--;
                  }
            }
            devq->active_dev = device;
            cam_ccbq_remove_ccb(&device->ccbq, work_ccb);

            cam_ccbq_send_ccb(&device->ccbq, work_ccb);
            splx(ospl);

            devq->send_openings--;
            devq->send_active++;          
            
            if (device->ccbq.queue.entries > 0)
                  xpt_schedule_dev_sendq(bus, device);

            if (work_ccb && (work_ccb->ccb_h.flags & CAM_DEV_QFREEZE) != 0){
                  /*
                   * The client wants to freeze the queue
                   * after this CCB is sent.
                   */
                  ospl = splcam();
                  device->qfrozen_cnt++;
                  splx(ospl);
            }
            
            splx(s);

            /* In Target mode, the peripheral driver knows best... */
            if (work_ccb->ccb_h.func_code == XPT_SCSI_IO) {
                  if ((device->inq_flags & SID_CmdQue) != 0
                   && work_ccb->csio.tag_action != CAM_TAG_ACTION_NONE)
                        work_ccb->ccb_h.flags |= CAM_TAG_ACTION_VALID;
                  else
                        /*
                         * Clear this in case of a retried CCB that
                         * failed due to a rejected tag.
                         */
                        work_ccb->ccb_h.flags &= ~CAM_TAG_ACTION_VALID;
            }

            /*
             * Device queues can be shared among multiple sim instances
             * that reside on different busses.  Use the SIM in the queue
             * CCB's path, rather than the one in the bus that was passed
             * into this function.
             */
            sim = work_ccb->ccb_h.path->bus->sim;
            (*(sim->sim_action))(sim, work_ccb);

            ospl = splcam();
            devq->active_dev = NULL;
            splx(ospl);
            /* Raise IPL for possible insertion and test at top of loop */
            s = splsoftcam();
      }
      splx(s);
      s = splcam();
      devq->send_queue.qfrozen_cnt--;
      splx(s);
}

/*
 * This function merges stuff from the slave ccb into the master ccb, while
 * keeping important fields in the master ccb constant.
 */
void
xpt_merge_ccb(union ccb *master_ccb, union ccb *slave_ccb)
{
      GIANT_REQUIRED;

      /*
       * Pull fields that are valid for peripheral drivers to set
       * into the master CCB along with the CCB "payload".
       */
      master_ccb->ccb_h.retry_count = slave_ccb->ccb_h.retry_count;
      master_ccb->ccb_h.func_code = slave_ccb->ccb_h.func_code;
      master_ccb->ccb_h.timeout = slave_ccb->ccb_h.timeout;
      master_ccb->ccb_h.flags = slave_ccb->ccb_h.flags;
      bcopy(&(&slave_ccb->ccb_h)[1], &(&master_ccb->ccb_h)[1],
            sizeof(union ccb) - sizeof(struct ccb_hdr));
}

void
xpt_setup_ccb(struct ccb_hdr *ccb_h, struct cam_path *path, u_int32_t priority)
{
      GIANT_REQUIRED;

      CAM_DEBUG(path, CAM_DEBUG_TRACE, ("xpt_setup_ccb\n"));
      ccb_h->pinfo.priority = priority;
      ccb_h->path = path;
      ccb_h->path_id = path->bus->path_id;
      if (path->target)
            ccb_h->target_id = path->target->target_id;
      else
            ccb_h->target_id = CAM_TARGET_WILDCARD;
      if (path->device) {
            ccb_h->target_lun = path->device->lun_id;
            ccb_h->pinfo.generation = ++path->device->ccbq.queue.generation;
      } else {
            ccb_h->target_lun = CAM_TARGET_WILDCARD;
      }
      ccb_h->pinfo.index = CAM_UNQUEUED_INDEX;
      ccb_h->flags = 0;
}

/* Path manipulation functions */
cam_status
xpt_create_path(struct cam_path **new_path_ptr, struct cam_periph *perph,
            path_id_t path_id, target_id_t target_id, lun_id_t lun_id)
{
      struct         cam_path *path;
      cam_status status;

      GIANT_REQUIRED;

      path = (struct cam_path *)malloc(sizeof(*path), M_CAMXPT, M_NOWAIT);

      if (path == NULL) {
            status = CAM_RESRC_UNAVAIL;
            return(status);
      }
      status = xpt_compile_path(path, perph, path_id, target_id, lun_id);
      if (status != CAM_REQ_CMP) {
            free(path, M_CAMXPT);
            path = NULL;
      }
      *new_path_ptr = path;
      return (status);
}

static cam_status
xpt_compile_path(struct cam_path *new_path, struct cam_periph *perph,
             path_id_t path_id, target_id_t target_id, lun_id_t lun_id)
{
      struct           cam_eb *bus;
      struct           cam_et *target;
      struct           cam_ed *device;
      cam_status   status;
      int        s;

      status = CAM_REQ_CMP;   /* Completed without error */
      target = NULL;          /* Wildcarded */
      device = NULL;          /* Wildcarded */

      /*
       * We will potentially modify the EDT, so block interrupts
       * that may attempt to create cam paths.
       */
      s = splcam();
      bus = xpt_find_bus(path_id);
      if (bus == NULL) {
            status = CAM_PATH_INVALID;
      } else {
            target = xpt_find_target(bus, target_id);
            if (target == NULL) {
                  /* Create one */
                  struct cam_et *new_target;

                  new_target = xpt_alloc_target(bus, target_id);
                  if (new_target == NULL) {
                        status = CAM_RESRC_UNAVAIL;
                  } else {
                        target = new_target;
                  }
            }
            if (target != NULL) {
                  device = xpt_find_device(target, lun_id);
                  if (device == NULL) {
                        /* Create one */
                        struct cam_ed *new_device;

                        new_device = xpt_alloc_device(bus,
                                                target,
                                                lun_id);
                        if (new_device == NULL) {
                              status = CAM_RESRC_UNAVAIL;
                        } else {
                              device = new_device;
                        }
                  }
            }
      }
      splx(s);

      /*
       * Only touch the user's data if we are successful.
       */
      if (status == CAM_REQ_CMP) {
            new_path->periph = perph;
            new_path->bus = bus;
            new_path->target = target;
            new_path->device = device;
            CAM_DEBUG(new_path, CAM_DEBUG_TRACE, ("xpt_compile_path\n"));
      } else {
            if (device != NULL)
                  xpt_release_device(bus, target, device);
            if (target != NULL)
                  xpt_release_target(bus, target);
            if (bus != NULL)
                  xpt_release_bus(bus);
      }
      return (status);
}

static void
xpt_release_path(struct cam_path *path)
{
      CAM_DEBUG(path, CAM_DEBUG_TRACE, ("xpt_release_path\n"));
      if (path->device != NULL) {
            xpt_release_device(path->bus, path->target, path->device);
            path->device = NULL;
      }
      if (path->target != NULL) {
            xpt_release_target(path->bus, path->target);
            path->target = NULL;
      }
      if (path->bus != NULL) {
            xpt_release_bus(path->bus);
            path->bus = NULL;
      }
}

void
xpt_free_path(struct cam_path *path)
{
      GIANT_REQUIRED;

      CAM_DEBUG(path, CAM_DEBUG_TRACE, ("xpt_free_path\n"));
      xpt_release_path(path);
      free(path, M_CAMXPT);
}


/*
 * Return -1 for failure, 0 for exact match, 1 for match with wildcards
 * in path1, 2 for match with wildcards in path2.
 */
int
xpt_path_comp(struct cam_path *path1, struct cam_path *path2)
{
      GIANT_REQUIRED;

      int retval = 0;

      if (path1->bus != path2->bus) {
            if (path1->bus->path_id == CAM_BUS_WILDCARD)
                  retval = 1;
            else if (path2->bus->path_id == CAM_BUS_WILDCARD)
                  retval = 2;
            else
                  return (-1);
      }
      if (path1->target != path2->target) {
            if (path1->target->target_id == CAM_TARGET_WILDCARD) {
                  if (retval == 0)
                        retval = 1;
            } else if (path2->target->target_id == CAM_TARGET_WILDCARD)
                  retval = 2;
            else
                  return (-1);
      }
      if (path1->device != path2->device) {
            if (path1->device->lun_id == CAM_LUN_WILDCARD) {
                  if (retval == 0)
                        retval = 1;
            } else if (path2->device->lun_id == CAM_LUN_WILDCARD)
                  retval = 2;
            else
                  return (-1);
      }
      return (retval);
}

void
xpt_print_path(struct cam_path *path)
{
      GIANT_REQUIRED;

      if (path == NULL)
            printf("(nopath): ");
      else {
            if (path->periph != NULL)
                  printf("(%s%d:", path->periph->periph_name,
                         path->periph->unit_number);
            else
                  printf("(noperiph:");

            if (path->bus != NULL)
                  printf("%s%d:%d:", path->bus->sim->sim_name,
                         path->bus->sim->unit_number,
                         path->bus->sim->bus_id);
            else
                  printf("nobus:");

            if (path->target != NULL)
                  printf("%d:", path->target->target_id);
            else
                  printf("X:");

            if (path->device != NULL)
                  printf("%d): ", path->device->lun_id);
            else
                  printf("X): ");
      }
}

void
xpt_print(struct cam_path *path, const char *fmt, ...)
{
      va_list ap;
      xpt_print_path(path);
      va_start(ap, fmt);
      vprintf(fmt, ap);
      va_end(ap);
}

int
xpt_path_string(struct cam_path *path, char *str, size_t str_len)
{
      struct sbuf sb;

      GIANT_REQUIRED;

      sbuf_new(&sb, str, str_len, 0);

      if (path == NULL)
            sbuf_printf(&sb, "(nopath): ");
      else {
            if (path->periph != NULL)
                  sbuf_printf(&sb, "(%s%d:", path->periph->periph_name,
                            path->periph->unit_number);
            else
                  sbuf_printf(&sb, "(noperiph:");

            if (path->bus != NULL)
                  sbuf_printf(&sb, "%s%d:%d:", path->bus->sim->sim_name,
                            path->bus->sim->unit_number,
                            path->bus->sim->bus_id);
            else
                  sbuf_printf(&sb, "nobus:");

            if (path->target != NULL)
                  sbuf_printf(&sb, "%d:", path->target->target_id);
            else
                  sbuf_printf(&sb, "X:");

            if (path->device != NULL)
                  sbuf_printf(&sb, "%d): ", path->device->lun_id);
            else
                  sbuf_printf(&sb, "X): ");
      }
      sbuf_finish(&sb);

      return(sbuf_len(&sb));
}

path_id_t
xpt_path_path_id(struct cam_path *path)
{
      GIANT_REQUIRED;

      return(path->bus->path_id);
}

target_id_t
xpt_path_target_id(struct cam_path *path)
{
      GIANT_REQUIRED;

      if (path->target != NULL)
            return (path->target->target_id);
      else
            return (CAM_TARGET_WILDCARD);
}

lun_id_t
xpt_path_lun_id(struct cam_path *path)
{
      GIANT_REQUIRED;

      if (path->device != NULL)
            return (path->device->lun_id);
      else
            return (CAM_LUN_WILDCARD);
}

struct cam_sim *
xpt_path_sim(struct cam_path *path)
{
      GIANT_REQUIRED;

      return (path->bus->sim);
}

struct cam_periph*
xpt_path_periph(struct cam_path *path)
{
      GIANT_REQUIRED;

      return (path->periph);
}

/*
 * Release a CAM control block for the caller.  Remit the cost of the structure
 * to the device referenced by the path.  If the this device had no 'credits'
 * and peripheral drivers have registered async callbacks for this notification
 * call them now.
 */
void
xpt_release_ccb(union ccb *free_ccb)
{
      int    s;
      struct       cam_path *path;
      struct       cam_ed *device;
      struct       cam_eb *bus;

      GIANT_REQUIRED;

      CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_release_ccb\n"));
      path = free_ccb->ccb_h.path;
      device = path->device;
      bus = path->bus;
      s = splsoftcam();
      cam_ccbq_release_opening(&device->ccbq);
      if (xpt_ccb_count > xpt_max_ccbs) {
            xpt_free_ccb(free_ccb);
            xpt_ccb_count--;
      } else {
            SLIST_INSERT_HEAD(&ccb_freeq, &free_ccb->ccb_h, xpt_links.sle);
      }
      if (bus->sim->devq == NULL) {
            splx(s);
            return;
      }
      bus->sim->devq->alloc_openings++;
      bus->sim->devq->alloc_active--;
      /* XXX Turn this into an inline function - xpt_run_device?? */
      if ((device_is_alloc_queued(device) == 0)
       && (device->drvq.entries > 0)) {
            xpt_schedule_dev_allocq(bus, device);
      }
      splx(s);
      if (dev_allocq_is_runnable(bus->sim->devq))
            xpt_run_dev_allocq(bus);
}

/* Functions accessed by SIM drivers */

/*
 * A sim structure, listing the SIM entry points and instance
 * identification info is passed to xpt_bus_register to hook the SIM
 * into the CAM framework.  xpt_bus_register creates a cam_eb entry
 * for this new bus and places it in the array of busses and assigns
 * it a path_id.  The path_id may be influenced by "hard wiring"
 * information specified by the user.  Once interrupt services are
 * availible, the bus will be probed.
 */
int32_t
xpt_bus_register(struct cam_sim *sim, u_int32_t bus)
{
      struct cam_eb *new_bus;
      struct cam_eb *old_bus;
      struct ccb_pathinq cpi;
      int s;

      GIANT_REQUIRED;

      sim->bus_id = bus;
      new_bus = (struct cam_eb *)malloc(sizeof(*new_bus),
                                M_CAMXPT, M_NOWAIT);
      if (new_bus == NULL) {
            /* Couldn't satisfy request */
            return (CAM_RESRC_UNAVAIL);
      }

      if (strcmp(sim->sim_name, "xpt") != 0) {

            sim->path_id =
                xptpathid(sim->sim_name, sim->unit_number, sim->bus_id);
      }

      TAILQ_INIT(&new_bus->et_entries);
      new_bus->path_id = sim->path_id;
      new_bus->sim = sim;
      timevalclear(&new_bus->last_reset);
      new_bus->flags = 0;
      new_bus->refcount = 1;  /* Held until a bus_deregister event */
      new_bus->generation = 0;
      s = splcam();
      old_bus = TAILQ_FIRST(&xpt_busses);
      while (old_bus != NULL
          && old_bus->path_id < new_bus->path_id)
            old_bus = TAILQ_NEXT(old_bus, links);
      if (old_bus != NULL)
            TAILQ_INSERT_BEFORE(old_bus, new_bus, links);
      else
            TAILQ_INSERT_TAIL(&xpt_busses, new_bus, links);
      bus_generation++;
      splx(s);

      /* Notify interested parties */
      if (sim->path_id != CAM_XPT_PATH_ID) {
            struct cam_path path;

            xpt_compile_path(&path, /*periph*/NULL, sim->path_id,
                           CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
            xpt_setup_ccb(&cpi.ccb_h, &path, /*priority*/1);
            cpi.ccb_h.func_code = XPT_PATH_INQ;
            xpt_action((union ccb *)&cpi);
            xpt_async(AC_PATH_REGISTERED, &path, &cpi);
            xpt_release_path(&path);
      }
      return (CAM_SUCCESS);
}

int32_t
xpt_bus_deregister(path_id_t pathid)
{
      struct cam_path bus_path;
      struct cam_ed *device;
      struct cam_ed_qinfo *qinfo;
      struct cam_devq *devq;
      struct cam_periph *periph;
      struct cam_sim *ccbsim;
      union ccb *work_ccb;
      cam_status status;

      GIANT_REQUIRED;

      status = xpt_compile_path(&bus_path, NULL, pathid,
                          CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
      if (status != CAM_REQ_CMP)
            return (status);

      xpt_async(AC_LOST_DEVICE, &bus_path, NULL);
      xpt_async(AC_PATH_DEREGISTERED, &bus_path, NULL);

      /* The SIM may be gone, so use a dummy SIM for any stray operations. */
      devq = bus_path.bus->sim->devq;
      bus_path.bus->sim = &cam_dead_sim;

      /* Execute any pending operations now. */
      while ((qinfo = (struct cam_ed_qinfo *)camq_remove(&devq->send_queue,
          CAMQ_HEAD)) != NULL ||
          (qinfo = (struct cam_ed_qinfo *)camq_remove(&devq->alloc_queue,
          CAMQ_HEAD)) != NULL) {
            do {
                  device = qinfo->device;
                  work_ccb = cam_ccbq_peek_ccb(&device->ccbq, CAMQ_HEAD);
                  if (work_ccb != NULL) {
                        devq->active_dev = device;
                        cam_ccbq_remove_ccb(&device->ccbq, work_ccb);
                        cam_ccbq_send_ccb(&device->ccbq, work_ccb);
                        ccbsim = work_ccb->ccb_h.path->bus->sim;
                        (*(ccbsim->sim_action))(ccbsim, work_ccb);
                  }

                  periph = (struct cam_periph *)camq_remove(&device->drvq,
                      CAMQ_HEAD);
                  if (periph != NULL)
                        xpt_schedule(periph, periph->pinfo.priority);
            } while (work_ccb != NULL || periph != NULL);
      }

      /* Make sure all completed CCBs are processed. */
      while (!TAILQ_EMPTY(&cam_bioq)) {
            camisr(&cam_bioq);

            /* Repeat the async's for the benefit of any new devices. */
            xpt_async(AC_LOST_DEVICE, &bus_path, NULL);
            xpt_async(AC_PATH_DEREGISTERED, &bus_path, NULL);
      }

      /* Release the reference count held while registered. */
      xpt_release_bus(bus_path.bus);
      xpt_release_path(&bus_path);

      /* Recheck for more completed CCBs. */
      while (!TAILQ_EMPTY(&cam_bioq))
            camisr(&cam_bioq);

      return (CAM_REQ_CMP);
}

static path_id_t
xptnextfreepathid(void)
{
      struct cam_eb *bus;
      path_id_t pathid;
      const char *strval;

      pathid = 0;
      bus = TAILQ_FIRST(&xpt_busses);
retry:
      /* Find an unoccupied pathid */
      while (bus != NULL
          && bus->path_id <= pathid) {
            if (bus->path_id == pathid)
                  pathid++;
            bus = TAILQ_NEXT(bus, links);
      }

      /*
       * Ensure that this pathid is not reserved for
       * a bus that may be registered in the future.
       */
      if (resource_string_value("scbus", pathid, "at", &strval) == 0) {
            ++pathid;
            /* Start the search over */
            goto retry;
      }
      return (pathid);
}

static path_id_t
xptpathid(const char *sim_name, int sim_unit, int sim_bus)
{
      path_id_t pathid;
      int i, dunit, val;
      char buf[32];
      const char *dname;

      pathid = CAM_XPT_PATH_ID;
      snprintf(buf, sizeof(buf), "%s%d", sim_name, sim_unit);
      i = 0;
      while ((resource_find_match(&i, &dname, &dunit, "at", buf)) == 0) {
            if (strcmp(dname, "scbus")) {
                  /* Avoid a bit of foot shooting. */
                  continue;
            }
            if (dunit < 0)          /* unwired?! */
                  continue;
            if (resource_int_value("scbus", dunit, "bus", &val) == 0) {
                  if (sim_bus == val) {
                        pathid = dunit;
                        break;
                  }
            } else if (sim_bus == 0) {
                  /* Unspecified matches bus 0 */
                  pathid = dunit;
                  break;
            } else {
                  printf("Ambiguous scbus configuration for %s%d "
                         "bus %d, cannot wire down.  The kernel "
                         "config entry for scbus%d should "
                         "specify a controller bus.\n"
                         "Scbus will be assigned dynamically.\n",
                         sim_name, sim_unit, sim_bus, dunit);
                  break;
            }
      }

      if (pathid == CAM_XPT_PATH_ID)
            pathid = xptnextfreepathid();
      return (pathid);
}

void
xpt_async(u_int32_t async_code, struct cam_path *path, void *async_arg)
{
      struct cam_eb *bus;
      struct cam_et *target, *next_target;
      struct cam_ed *device, *next_device;
      int s;

      GIANT_REQUIRED;

      CAM_DEBUG(path, CAM_DEBUG_TRACE, ("xpt_async\n"));

      /*
       * Most async events come from a CAM interrupt context.  In
       * a few cases, the error recovery code at the peripheral layer,
       * which may run from our SWI or a process context, may signal
       * deferred events with a call to xpt_async. Ensure async
       * notifications are serialized by blocking cam interrupts.
       */
      s = splcam();

      bus = path->bus;

      if (async_code == AC_BUS_RESET) { 
            int s;

            s = splclock();
            /* Update our notion of when the last reset occurred */
            microtime(&bus->last_reset);
            splx(s);
      }

      for (target = TAILQ_FIRST(&bus->et_entries);
           target != NULL;
           target = next_target) {

            next_target = TAILQ_NEXT(target, links);

            if (path->target != target
             && path->target->target_id != CAM_TARGET_WILDCARD
             && target->target_id != CAM_TARGET_WILDCARD)
                  continue;

            if (async_code == AC_SENT_BDR) {
                  int s;

                  /* Update our notion of when the last reset occurred */
                  s = splclock();
                  microtime(&path->target->last_reset);
                  splx(s);
            }

            for (device = TAILQ_FIRST(&target->ed_entries);
                 device != NULL;
                 device = next_device) {

                  next_device = TAILQ_NEXT(device, links);

                  if (path->device != device 
                   && path->device->lun_id != CAM_LUN_WILDCARD
                   && device->lun_id != CAM_LUN_WILDCARD)
                        continue;

                  xpt_dev_async(async_code, bus, target,
                              device, async_arg);

                  xpt_async_bcast(&device->asyncs, async_code,
                              path, async_arg);
            }
      }
      
      /*
       * If this wasn't a fully wildcarded async, tell all
       * clients that want all async events.
       */
      if (bus != xpt_periph->path->bus)
            xpt_async_bcast(&xpt_periph->path->device->asyncs, async_code,
                        path, async_arg);
      splx(s);
}

static void
xpt_async_bcast(struct async_list *async_head,
            u_int32_t async_code,
            struct cam_path *path, void *async_arg)
{
      struct async_node *cur_entry;

      cur_entry = SLIST_FIRST(async_head);
      while (cur_entry != NULL) {
            struct async_node *next_entry;
            /*
             * Grab the next list entry before we call the current
             * entry's callback.  This is because the callback function
             * can delete its async callback entry.
             */
            next_entry = SLIST_NEXT(cur_entry, links);
            if ((cur_entry->event_enable & async_code) != 0)
                  cur_entry->callback(cur_entry->callback_arg,
                                  async_code, path,
                                  async_arg);
            cur_entry = next_entry;
      }
}

/*
 * Handle any per-device event notifications that require action by the XPT.
 */
static void
xpt_dev_async(u_int32_t async_code, struct cam_eb *bus, struct cam_et *target,
            struct cam_ed *device, void *async_arg)
{
      cam_status status;
      struct cam_path newpath;

      /*
       * We only need to handle events for real devices.
       */
      if (target->target_id == CAM_TARGET_WILDCARD
       || device->lun_id == CAM_LUN_WILDCARD)
            return;

      /*
       * We need our own path with wildcards expanded to
       * handle certain types of events.
       */
      if ((async_code == AC_SENT_BDR)
       || (async_code == AC_BUS_RESET)
       || (async_code == AC_INQ_CHANGED))
            status = xpt_compile_path(&newpath, NULL,
                                bus->path_id,
                                target->target_id,
                                device->lun_id);
      else
            status = CAM_REQ_CMP_ERR;

      if (status == CAM_REQ_CMP) {

            /*
             * Allow transfer negotiation to occur in a
             * tag free environment.
             */
            if (async_code == AC_SENT_BDR
             || async_code == AC_BUS_RESET)
                  xpt_toggle_tags(&newpath);

            if (async_code == AC_INQ_CHANGED) {
                  /*
                   * We've sent a start unit command, or
                   * something similar to a device that
                   * may have caused its inquiry data to
                   * change. So we re-scan the device to
                   * refresh the inquiry data for it.
                   */
                  xpt_scan_lun(newpath.periph, &newpath,
                             CAM_EXPECT_INQ_CHANGE, NULL);
            }
            xpt_release_path(&newpath);
      } else if (async_code == AC_LOST_DEVICE) {
            device->flags |= CAM_DEV_UNCONFIGURED;
      } else if (async_code == AC_TRANSFER_NEG) {
            struct ccb_trans_settings *settings;

            settings = (struct ccb_trans_settings *)async_arg;
            xpt_set_transfer_settings(settings, device,
                                /*async_update*/TRUE);
      }
}

u_int32_t
xpt_freeze_devq(struct cam_path *path, u_int count)
{
      int s;
      struct ccb_hdr *ccbh;

      GIANT_REQUIRED;

      s = splcam();
      path->device->qfrozen_cnt += count;

      /*
       * Mark the last CCB in the queue as needing
       * to be requeued if the driver hasn't
       * changed it's state yet.  This fixes a race
       * where a ccb is just about to be queued to
       * a controller driver when it's interrupt routine
       * freezes the queue.  To completly close the
       * hole, controller drives must check to see
       * if a ccb's status is still CAM_REQ_INPROG
       * under spl protection just before they queue
       * the CCB.  See ahc_action/ahc_freeze_devq for
       * an example.
       */
      ccbh = TAILQ_LAST(&path->device->ccbq.active_ccbs, ccb_hdr_tailq);
      if (ccbh && ccbh->status == CAM_REQ_INPROG)
            ccbh->status = CAM_REQUEUE_REQ;
      splx(s);
      return (path->device->qfrozen_cnt);
}

u_int32_t
xpt_freeze_simq(struct cam_sim *sim, u_int count)
{
      GIANT_REQUIRED;

      sim->devq->send_queue.qfrozen_cnt += count;
      if (sim->devq->active_dev != NULL) {
            struct ccb_hdr *ccbh;
            
            ccbh = TAILQ_LAST(&sim->devq->active_dev->ccbq.active_ccbs,
                          ccb_hdr_tailq);
            if (ccbh && ccbh->status == CAM_REQ_INPROG)
                  ccbh->status = CAM_REQUEUE_REQ;
      }
      return (sim->devq->send_queue.qfrozen_cnt);
}

static void
xpt_release_devq_timeout(void *arg)
{
      struct cam_ed *device;

      device = (struct cam_ed *)arg;

      xpt_release_devq_device(device, /*count*/1, /*run_queue*/TRUE);
}

void
xpt_release_devq(struct cam_path *path, u_int count, int run_queue)
{
      GIANT_REQUIRED;

      xpt_release_devq_device(path->device, count, run_queue);
}

static void
xpt_release_devq_device(struct cam_ed *dev, u_int count, int run_queue)
{
      int   rundevq;
      int   s0, s1;

      rundevq = 0;
      s0 = splsoftcam();
      s1 = splcam();
      if (dev->qfrozen_cnt > 0) {

            count = (count > dev->qfrozen_cnt) ? dev->qfrozen_cnt : count;
            dev->qfrozen_cnt -= count;
            if (dev->qfrozen_cnt == 0) {

                  /*
                   * No longer need to wait for a successful
                   * command completion.
                   */
                  dev->flags &= ~CAM_DEV_REL_ON_COMPLETE;

                  /*
                   * Remove any timeouts that might be scheduled
                   * to release this queue.
                   */
                  if ((dev->flags & CAM_DEV_REL_TIMEOUT_PENDING) != 0) {
                        untimeout(xpt_release_devq_timeout, dev,
                                dev->c_handle);
                        dev->flags &= ~CAM_DEV_REL_TIMEOUT_PENDING;
                  }

                  /*
                   * Now that we are unfrozen schedule the
                   * device so any pending transactions are
                   * run.
                   */
                  if ((dev->ccbq.queue.entries > 0)
                   && (xpt_schedule_dev_sendq(dev->target->bus, dev))
                   && (run_queue != 0)) {
                        rundevq = 1;
                  }
            }
      }
      splx(s1);
      if (rundevq != 0)
            xpt_run_dev_sendq(dev->target->bus);
      splx(s0);
}

void
xpt_release_simq(struct cam_sim *sim, int run_queue)
{
      int   s;
      struct      camq *sendq;

      GIANT_REQUIRED;

      sendq = &(sim->devq->send_queue);
      s = splcam();
      if (sendq->qfrozen_cnt > 0) {

            sendq->qfrozen_cnt--;
            if (sendq->qfrozen_cnt == 0) {
                  struct cam_eb *bus;

                  /*
                   * If there is a timeout scheduled to release this
                   * sim queue, remove it.  The queue frozen count is
                   * already at 0.
                   */
                  if ((sim->flags & CAM_SIM_REL_TIMEOUT_PENDING) != 0){
                        untimeout(xpt_release_simq_timeout, sim,
                                sim->c_handle);
                        sim->flags &= ~CAM_SIM_REL_TIMEOUT_PENDING;
                  }
                  bus = xpt_find_bus(sim->path_id);
                  splx(s);

                  if (run_queue) {
                        /*
                         * Now that we are unfrozen run the send queue.
                         */
                        xpt_run_dev_sendq(bus);
                  }
                  xpt_release_bus(bus);
            } else
                  splx(s);
      } else
            splx(s);
}

static void
xpt_release_simq_timeout(void *arg)
{
      struct cam_sim *sim;

      sim = (struct cam_sim *)arg;
      xpt_release_simq(sim, /* run_queue */ TRUE);
}

void
xpt_done(union ccb *done_ccb)
{
      int s;

      s = splcam();

      CAM_DEBUG(done_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("xpt_done\n"));
      if ((done_ccb->ccb_h.func_code & XPT_FC_QUEUED) != 0) {
            /*
             * Queue up the request for handling by our SWI handler
             * any of the "non-immediate" type of ccbs.
             */
            switch (done_ccb->ccb_h.path->periph->type) {
            case CAM_PERIPH_BIO:
                  mtx_lock(&cam_bioq_lock);
                  TAILQ_INSERT_TAIL(&cam_bioq, &done_ccb->ccb_h,
                                sim_links.tqe);
                  done_ccb->ccb_h.pinfo.index = CAM_DONEQ_INDEX;
                  mtx_unlock(&cam_bioq_lock);
                  swi_sched(cambio_ih, 0);
                  break;
            default:
                  panic("unknown periph type %d",
                      done_ccb->ccb_h.path->periph->type);
            }
      }
      splx(s);
}

union ccb *
xpt_alloc_ccb()
{
      union ccb *new_ccb;

      GIANT_REQUIRED;

      new_ccb = malloc(sizeof(*new_ccb), M_CAMXPT, M_WAITOK);
      return (new_ccb);
}

union ccb *
xpt_alloc_ccb_nowait()
{
      union ccb *new_ccb;

      GIANT_REQUIRED;

      new_ccb = malloc(sizeof(*new_ccb), M_CAMXPT, M_NOWAIT);
      return (new_ccb);
}

void
xpt_free_ccb(union ccb *free_ccb)
{
      free(free_ccb, M_CAMXPT);
}



/* Private XPT functions */

/*
 * Get a CAM control block for the caller. Charge the structure to the device
 * referenced by the path.  If the this device has no 'credits' then the
 * device already has the maximum number of outstanding operations under way
 * and we return NULL. If we don't have sufficient resources to allocate more
 * ccbs, we also return NULL.
 */
static union ccb *
xpt_get_ccb(struct cam_ed *device)
{
      union ccb *new_ccb;
      int s;

      s = splsoftcam();
      if ((new_ccb = (union ccb *)SLIST_FIRST(&ccb_freeq)) == NULL) {
            new_ccb = xpt_alloc_ccb_nowait();
                if (new_ccb == NULL) {
                  splx(s);
                  return (NULL);
            }
            callout_handle_init(&new_ccb->ccb_h.timeout_ch);
            SLIST_INSERT_HEAD(&ccb_freeq, &new_ccb->ccb_h,
                          xpt_links.sle);
            xpt_ccb_count++;
      }
      cam_ccbq_take_opening(&device->ccbq);
      SLIST_REMOVE_HEAD(&ccb_freeq, xpt_links.sle);
      splx(s);
      return (new_ccb);
}

static void
xpt_release_bus(struct cam_eb *bus)
{
      int s;

      s = splcam();
      if ((--bus->refcount == 0)
       && (TAILQ_FIRST(&bus->et_entries) == NULL)) {
            TAILQ_REMOVE(&xpt_busses, bus, links);
            bus_generation++;
            splx(s);
            free(bus, M_CAMXPT);
      } else
            splx(s);
}

static struct cam_et *
xpt_alloc_target(struct cam_eb *bus, target_id_t target_id)
{
      struct cam_et *target;

      target = (struct cam_et *)malloc(sizeof(*target), M_CAMXPT, M_NOWAIT);
      if (target != NULL) {
            struct cam_et *cur_target;

            TAILQ_INIT(&target->ed_entries);
            target->bus = bus;
            target->target_id = target_id;
            target->refcount = 1;
            target->generation = 0;
            timevalclear(&target->last_reset);
            /*
             * Hold a reference to our parent bus so it
             * will not go away before we do.
             */
            bus->refcount++;

            /* Insertion sort into our bus's target list */
            cur_target = TAILQ_FIRST(&bus->et_entries);
            while (cur_target != NULL && cur_target->target_id < target_id)
                  cur_target = TAILQ_NEXT(cur_target, links);

            if (cur_target != NULL) {
                  TAILQ_INSERT_BEFORE(cur_target, target, links);
            } else {
                  TAILQ_INSERT_TAIL(&bus->et_entries, target, links);
            }
            bus->generation++;
      }
      return (target);
}

static void
xpt_release_target(struct cam_eb *bus, struct cam_et *target)
{
      int s;

      s = splcam();
      if ((--target->refcount == 0)
       && (TAILQ_FIRST(&target->ed_entries) == NULL)) {
            TAILQ_REMOVE(&bus->et_entries, target, links);
            bus->generation++;
            splx(s);
            free(target, M_CAMXPT);
            xpt_release_bus(bus);
      } else
            splx(s);
}

static struct cam_ed *
xpt_alloc_device(struct cam_eb *bus, struct cam_et *target, lun_id_t lun_id)
{
#ifdef CAM_NEW_TRAN_CODE
      struct         cam_path path;
#endif /* CAM_NEW_TRAN_CODE */
      struct         cam_ed *device;
      struct         cam_devq *devq;
      cam_status status;

      if (SIM_DEAD(bus->sim))
            return (NULL);

      /* Make space for us in the device queue on our bus */
      devq = bus->sim->devq;
      status = cam_devq_resize(devq, devq->alloc_queue.array_size + 1);

      if (status != CAM_REQ_CMP) {
            device = NULL;
      } else {
            device = (struct cam_ed *)malloc(sizeof(*device),
                                     M_CAMXPT, M_NOWAIT);
      }

      if (device != NULL) {
            struct cam_ed *cur_device;

            cam_init_pinfo(&device->alloc_ccb_entry.pinfo);
            device->alloc_ccb_entry.device = device;
            cam_init_pinfo(&device->send_ccb_entry.pinfo);
            device->send_ccb_entry.device = device;
            device->target = target;
            device->lun_id = lun_id;
            /* Initialize our queues */
            if (camq_init(&device->drvq, 0) != 0) {
                  free(device, M_CAMXPT);
                  return (NULL);
            }
            if (cam_ccbq_init(&device->ccbq,
                          bus->sim->max_dev_openings) != 0) {
                  camq_fini(&device->drvq);
                  free(device, M_CAMXPT);
                  return (NULL);
            }
            SLIST_INIT(&device->asyncs);
            SLIST_INIT(&device->periphs);
            device->generation = 0;
            device->owner = NULL;
            /*
             * Take the default quirk entry until we have inquiry
             * data and can determine a better quirk to use.
             */
            device->quirk = &xpt_quirk_table[xpt_quirk_table_size - 1];
            bzero(&device->inq_data, sizeof(device->inq_data));
            device->inq_flags = 0;
            device->queue_flags = 0;
            device->serial_num = NULL;
            device->serial_num_len = 0;
            device->qfrozen_cnt = 0;
            device->flags = CAM_DEV_UNCONFIGURED;
            device->tag_delay_count = 0;
            device->tag_saved_openings = 0;
            device->refcount = 1;
            callout_handle_init(&device->c_handle);

            /*
             * Hold a reference to our parent target so it
             * will not go away before we do.
             */
            target->refcount++;

            /*
             * XXX should be limited by number of CCBs this bus can
             * do.
             */
            xpt_max_ccbs += device->ccbq.devq_openings;
            /* Insertion sort into our target's device list */
            cur_device = TAILQ_FIRST(&target->ed_entries);
            while (cur_device != NULL && cur_device->lun_id < lun_id)
                  cur_device = TAILQ_NEXT(cur_device, links);
            if (cur_device != NULL) {
                  TAILQ_INSERT_BEFORE(cur_device, device, links);
            } else {
                  TAILQ_INSERT_TAIL(&target->ed_entries, device, links);
            }
            target->generation++;
#ifdef CAM_NEW_TRAN_CODE
            if (lun_id != CAM_LUN_WILDCARD) {
                  xpt_compile_path(&path,
                               NULL,
                               bus->path_id,
                               target->target_id,
                               lun_id);
                  xpt_devise_transport(&path);
                  xpt_release_path(&path);
            }
#endif /* CAM_NEW_TRAN_CODE */
      }
      return (device);
}

static void
xpt_release_device(struct cam_eb *bus, struct cam_et *target,
               struct cam_ed *device)
{
      int s;

      s = splcam();
      if ((--device->refcount == 0)
       && ((device->flags & CAM_DEV_UNCONFIGURED) != 0)) {
            struct cam_devq *devq;

            if (device->alloc_ccb_entry.pinfo.index != CAM_UNQUEUED_INDEX
             || device->send_ccb_entry.pinfo.index != CAM_UNQUEUED_INDEX)
                  panic("Removing device while still queued for ccbs");

            if ((device->flags & CAM_DEV_REL_TIMEOUT_PENDING) != 0)
                        untimeout(xpt_release_devq_timeout, device,
                                device->c_handle);

            TAILQ_REMOVE(&target->ed_entries, device,links);
            target->generation++;
            xpt_max_ccbs -= device->ccbq.devq_openings;
            if (!SIM_DEAD(bus->sim)) {
                  /* Release our slot in the devq */
                  devq = bus->sim->devq;
                  cam_devq_resize(devq, devq->alloc_queue.array_size - 1);
            }
            splx(s);
            camq_fini(&device->drvq);
            camq_fini(&device->ccbq.queue);
            free(device, M_CAMXPT);
            xpt_release_target(bus, target);
      } else
            splx(s);
}

static u_int32_t
xpt_dev_ccbq_resize(struct cam_path *path, int newopenings)
{
      int   s;
      int   diff;
      int   result;
      struct      cam_ed *dev;

      dev = path->device;
      s = splsoftcam();

      diff = newopenings - (dev->ccbq.dev_active + dev->ccbq.dev_openings);
      result = cam_ccbq_resize(&dev->ccbq, newopenings);
      if (result == CAM_REQ_CMP && (diff < 0)) {
            dev->flags |= CAM_DEV_RESIZE_QUEUE_NEEDED;
      }
      if ((dev->flags & CAM_DEV_TAG_AFTER_COUNT) != 0
       || (dev->inq_flags & SID_CmdQue) != 0)
            dev->tag_saved_openings = newopenings;
      /* Adjust the global limit */
      xpt_max_ccbs += diff;
      splx(s);
      return (result);
}

static struct cam_eb *
xpt_find_bus(path_id_t path_id)
{
      struct cam_eb *bus;

      for (bus = TAILQ_FIRST(&xpt_busses);
           bus != NULL;
           bus = TAILQ_NEXT(bus, links)) {
            if (bus->path_id == path_id) {
                  bus->refcount++;
                  break;
            }
      }
      return (bus);
}

static struct cam_et *
xpt_find_target(struct cam_eb *bus, target_id_t target_id)
{
      struct cam_et *target;

      for (target = TAILQ_FIRST(&bus->et_entries);
           target != NULL;
           target = TAILQ_NEXT(target, links)) {
            if (target->target_id == target_id) {
                  target->refcount++;
                  break;
            }
      }
      return (target);
}

static struct cam_ed *
xpt_find_device(struct cam_et *target, lun_id_t lun_id)
{
      struct cam_ed *device;

      for (device = TAILQ_FIRST(&target->ed_entries);
           device != NULL;
           device = TAILQ_NEXT(device, links)) {
            if (device->lun_id == lun_id) {
                  device->refcount++;
                  break;
            }
      }
      return (device);
}

typedef struct {
      union ccb *request_ccb;
      struct      ccb_pathinq *cpi;
      int   counter;
} xpt_scan_bus_info;

static void
xpt_scan_bus(struct cam_periph *periph, union ccb *request_ccb)
{
      CAM_DEBUG(request_ccb->ccb_h.path, CAM_DEBUG_TRACE,
              ("xpt_scan_bus\n"));
      switch (request_ccb->ccb_h.func_code) {
      case XPT_SCAN_BUS:
      {
            xpt_scan_bus_info *scan_info;
            union ccb *work_ccb;
            struct      cam_path *path;
            u_int i;
            u_int max_target;
            u_int initiator_id;

            /* Find out the characteristics of the bus */
            work_ccb = xpt_alloc_ccb();
            xpt_setup_ccb(&work_ccb->ccb_h, request_ccb->ccb_h.path,
                request_ccb->ccb_h.pinfo.priority);
            work_ccb->ccb_h.func_code = XPT_PATH_INQ;
            xpt_action(work_ccb);
            if (work_ccb->ccb_h.status != CAM_REQ_CMP) {
                  request_ccb->ccb_h.status = work_ccb->ccb_h.status;
                  xpt_free_ccb(work_ccb);
                  xpt_done(request_ccb);
                  return;
            }

            if ((work_ccb->cpi.hba_misc & PIM_NOINITIATOR) != 0) {
                  /*
                   * Can't scan the bus on an adapter that
                   * cannot perform the initiator role.
                   */
                  request_ccb->ccb_h.status = CAM_REQ_CMP;
                  xpt_free_ccb(work_ccb);
                  xpt_done(request_ccb);
                  return;
            }

            /* Save some state for use while we probe for devices */
            scan_info = (xpt_scan_bus_info *)
                malloc(sizeof(xpt_scan_bus_info), M_TEMP, M_WAITOK);
            scan_info->request_ccb = request_ccb;
            scan_info->cpi = &work_ccb->cpi;

            /* Cache on our stack so we can work asynchronously */
            max_target = scan_info->cpi->max_target;
            initiator_id = scan_info->cpi->initiator_id;


            /*
             * We can scan all targets in parallel, or do it sequentially.
             */
            if (scan_info->cpi->hba_misc & PIM_SEQSCAN) {
                  max_target = 0;
                  scan_info->counter = 0;
            } else {
                  scan_info->counter = scan_info->cpi->max_target + 1;
                  if (scan_info->cpi->initiator_id < scan_info->counter) {
                        scan_info->counter--;
                  }
            }
            
            for (i = 0; i <= max_target; i++) {
                  cam_status status;
                  if (i == initiator_id)
                        continue;

                  status = xpt_create_path(&path, xpt_periph,
                                           request_ccb->ccb_h.path_id,
                                                 i, 0);
                  if (status != CAM_REQ_CMP) {
                        printf("xpt_scan_bus: xpt_create_path failed"
                               " with status %#x, bus scan halted\n",
                               status);
                        free(scan_info, M_TEMP);
                        request_ccb->ccb_h.status = status;
                        xpt_free_ccb(work_ccb);
                        xpt_done(request_ccb);
                        break;
                  }
                  work_ccb = xpt_alloc_ccb();
                  xpt_setup_ccb(&work_ccb->ccb_h, path,
                      request_ccb->ccb_h.pinfo.priority);
                  work_ccb->ccb_h.func_code = XPT_SCAN_LUN;
                  work_ccb->ccb_h.cbfcnp = xpt_scan_bus;
                  work_ccb->ccb_h.ppriv_ptr0 = scan_info;
                  work_ccb->crcn.flags = request_ccb->crcn.flags;
                  xpt_action(work_ccb);
            }
            break;
      }
      case XPT_SCAN_LUN:
      {
            cam_status status;
            struct cam_path *path;
            xpt_scan_bus_info *scan_info;
            path_id_t path_id;
            target_id_t target_id;
            lun_id_t lun_id;

            /* Reuse the same CCB to query if a device was really found */
            scan_info = (xpt_scan_bus_info *)request_ccb->ccb_h.ppriv_ptr0;
            xpt_setup_ccb(&request_ccb->ccb_h, request_ccb->ccb_h.path,
                request_ccb->ccb_h.pinfo.priority);
            request_ccb->ccb_h.func_code = XPT_GDEV_TYPE;

            path_id = request_ccb->ccb_h.path_id;
            target_id = request_ccb->ccb_h.target_id;
            lun_id = request_ccb->ccb_h.target_lun;
            xpt_action(request_ccb);

            if (request_ccb->ccb_h.status != CAM_REQ_CMP) {
                  struct cam_ed *device;
                  struct cam_et *target;
                  int s, phl;

                  /*
                   * If we already probed lun 0 successfully, or
                   * we have additional configured luns on this
                   * target that might have "gone away", go onto
                   * the next lun.
                   */
                  target = request_ccb->ccb_h.path->target;
                  /*
                   * We may touch devices that we don't
                   * hold references too, so ensure they
                   * don't disappear out from under us.
                   * The target above is referenced by the
                   * path in the request ccb.
                   */
                  phl = 0;
                  s = splcam();
                  device = TAILQ_FIRST(&target->ed_entries);
                  if (device != NULL) {
                        phl = CAN_SRCH_HI_SPARSE(device);
                        if (device->lun_id == 0)
                              device = TAILQ_NEXT(device, links);
                  }
                  splx(s);
                  if ((lun_id != 0) || (device != NULL)) {
                        if (lun_id < (CAM_SCSI2_MAXLUN-1) || phl)
                              lun_id++;
                  }
            } else {
                  struct cam_ed *device;
                  
                  device = request_ccb->ccb_h.path->device;

                  if ((device->quirk->quirks & CAM_QUIRK_NOLUNS) == 0) {
                        /* Try the next lun */
                        if (lun_id < (CAM_SCSI2_MAXLUN-1)
                          || CAN_SRCH_HI_DENSE(device))
                              lun_id++;
                  }
            }

            /*
             * Free the current request path- we're done with it.
             */
            xpt_free_path(request_ccb->ccb_h.path);

            /*
             * Check to see if we scan any further luns.
             */
            if (lun_id == request_ccb->ccb_h.target_lun
                 || lun_id > scan_info->cpi->max_lun) {
                  int done;

 hop_again:
                  done = 0;
                  if (scan_info->cpi->hba_misc & PIM_SEQSCAN) {
                        scan_info->counter++;
                        if (scan_info->counter == 
                            scan_info->cpi->initiator_id) {
                              scan_info->counter++;
                        }
                        if (scan_info->counter >=
                            scan_info->cpi->max_target+1) {
                              done = 1;
                        }
                  } else {
                        scan_info->counter--;
                        if (scan_info->counter == 0) {
                              done = 1;
                        }
                  }
                  if (done) {
                        xpt_free_ccb(request_ccb);
                        xpt_free_ccb((union ccb *)scan_info->cpi);
                        request_ccb = scan_info->request_ccb;
                        free(scan_info, M_TEMP);
                        request_ccb->ccb_h.status = CAM_REQ_CMP;
                        xpt_done(request_ccb);
                        break;
                  }

                  if ((scan_info->cpi->hba_misc & PIM_SEQSCAN) == 0) {
                        break;
                  }
                  status = xpt_create_path(&path, xpt_periph,
                      scan_info->request_ccb->ccb_h.path_id,
                      scan_info->counter, 0);
                  if (status != CAM_REQ_CMP) {
                        printf("xpt_scan_bus: xpt_create_path failed"
                            " with status %#x, bus scan halted\n",
                                  status);
                        xpt_free_ccb(request_ccb);
                        xpt_free_ccb((union ccb *)scan_info->cpi);
                        request_ccb = scan_info->request_ccb;
                        free(scan_info, M_TEMP);
                        request_ccb->ccb_h.status = status;
                        xpt_done(request_ccb);
                        break;
                  }
                  xpt_setup_ccb(&request_ccb->ccb_h, path,
                      request_ccb->ccb_h.pinfo.priority);
                  request_ccb->ccb_h.func_code = XPT_SCAN_LUN;
                  request_ccb->ccb_h.cbfcnp = xpt_scan_bus;
                  request_ccb->ccb_h.ppriv_ptr0 = scan_info;
                  request_ccb->crcn.flags =
                      scan_info->request_ccb->crcn.flags;
            } else {
                  status = xpt_create_path(&path, xpt_periph,
                      path_id, target_id, lun_id);
                  if (status != CAM_REQ_CMP) {
                        printf("xpt_scan_bus: xpt_create_path failed "
                               "with status %#x, halting LUN scan\n",
                               status);
                        goto hop_again;
                  }
                  xpt_setup_ccb(&request_ccb->ccb_h, path,
                        request_ccb->ccb_h.pinfo.priority);
                  request_ccb->ccb_h.func_code = XPT_SCAN_LUN;
                  request_ccb->ccb_h.cbfcnp = xpt_scan_bus;
                  request_ccb->ccb_h.ppriv_ptr0 = scan_info;
                  request_ccb->crcn.flags =
                        scan_info->request_ccb->crcn.flags;
            }
            xpt_action(request_ccb);
            break;
      }
      default:
            break;
      }
}

typedef enum {
      PROBE_TUR,
      PROBE_INQUIRY,
      PROBE_FULL_INQUIRY,
      PROBE_MODE_SENSE,
      PROBE_SERIAL_NUM,
      PROBE_TUR_FOR_NEGOTIATION
} probe_action;

typedef enum {
      PROBE_INQUIRY_CKSUM     = 0x01,
      PROBE_SERIAL_CKSUM      = 0x02,
      PROBE_NO_ANNOUNCE = 0x04
} probe_flags;

typedef struct {
      TAILQ_HEAD(, ccb_hdr) request_ccbs;
      probe_action      action;
      union ccb   saved_ccb;
      probe_flags flags;
      MD5_CTX           context;
      u_int8_t    digest[16];
} probe_softc;

static void
xpt_scan_lun(struct cam_periph *periph, struct cam_path *path,
           cam_flags flags, union ccb *request_ccb)
{
      struct ccb_pathinq cpi;
      cam_status status;
      struct cam_path *new_path;
      struct cam_periph *old_periph;
      int s;
      
      CAM_DEBUG(request_ccb->ccb_h.path, CAM_DEBUG_TRACE,
              ("xpt_scan_lun\n"));
      
      xpt_setup_ccb(&cpi.ccb_h, path, /*priority*/1);
      cpi.ccb_h.func_code = XPT_PATH_INQ;
      xpt_action((union ccb *)&cpi);

      if (cpi.ccb_h.status != CAM_REQ_CMP) {
            if (request_ccb != NULL) {
                  request_ccb->ccb_h.status = cpi.ccb_h.status;
                  xpt_done(request_ccb);
            }
            return;
      }

      if ((cpi.hba_misc & PIM_NOINITIATOR) != 0) {
            /*
             * Can't scan the bus on an adapter that
             * cannot perform the initiator role.
             */
            if (request_ccb != NULL) {
                  request_ccb->ccb_h.status = CAM_REQ_CMP;
                  xpt_done(request_ccb);
            }
            return;
      }

      if (request_ccb == NULL) {
            request_ccb = malloc(sizeof(union ccb), M_TEMP, M_NOWAIT);
            if (request_ccb == NULL) {
                  xpt_print_path(path);
                  printf("xpt_scan_lun: can't allocate CCB, can't "
                         "continue\n");
                  return;
            }
            new_path = malloc(sizeof(*new_path), M_TEMP, M_NOWAIT);
            if (new_path == NULL) {
                  xpt_print_path(path);
                  printf("xpt_scan_lun: can't allocate path, can't "
                         "continue\n");
                  free(request_ccb, M_TEMP);
                  return;
            }
            status = xpt_compile_path(new_path, xpt_periph,
                                path->bus->path_id,
                                path->target->target_id,
                                path->device->lun_id);

            if (status != CAM_REQ_CMP) {
                  xpt_print_path(path);
                  printf("xpt_scan_lun: can't compile path, can't "
                         "continue\n");
                  free(request_ccb, M_TEMP);
                  free(new_path, M_TEMP);
                  return;
            }
            xpt_setup_ccb(&request_ccb->ccb_h, new_path, /*priority*/ 1);
            request_ccb->ccb_h.cbfcnp = xptscandone;
            request_ccb->ccb_h.func_code = XPT_SCAN_LUN;
            request_ccb->crcn.flags = flags;
      }

      s = splsoftcam();
      if ((old_periph = cam_periph_find(path, "probe")) != NULL) {
            probe_softc *softc;

            softc = (probe_softc *)old_periph->softc;
            TAILQ_INSERT_TAIL(&softc->request_ccbs, &request_ccb->ccb_h,
                          periph_links.tqe);
      } else {
            status = cam_periph_alloc(proberegister, NULL, probecleanup,
                                probestart, "probe",
                                CAM_PERIPH_BIO,
                                request_ccb->ccb_h.path, NULL, 0,
                                request_ccb);

            if (status != CAM_REQ_CMP) {
                  xpt_print_path(path);
                  printf("xpt_scan_lun: cam_alloc_periph returned an "
                         "error, can't continue probe\n");
                  request_ccb->ccb_h.status = status;
                  xpt_done(request_ccb);
            }
      }
      splx(s);
}

static void
xptscandone(struct cam_periph *periph, union ccb *done_ccb)
{
      xpt_release_path(done_ccb->ccb_h.path);
      free(done_ccb->ccb_h.path, M_TEMP);
      free(done_ccb, M_TEMP);
}

static cam_status
proberegister(struct cam_periph *periph, void *arg)
{
      union ccb *request_ccb; /* CCB representing the probe request */
      probe_softc *softc;

      request_ccb = (union ccb *)arg;
      if (periph == NULL) {
            printf("proberegister: periph was NULL!!\n");
            return(CAM_REQ_CMP_ERR);
      }

      if (request_ccb == NULL) {
            printf("proberegister: no probe CCB, "
                   "can't register device\n");
            return(CAM_REQ_CMP_ERR);
      }

      softc = (probe_softc *)malloc(sizeof(*softc), M_TEMP, M_NOWAIT);

      if (softc == NULL) {
            printf("proberegister: Unable to probe new device. "
                   "Unable to allocate softc\n");                       
            return(CAM_REQ_CMP_ERR);
      }
      TAILQ_INIT(&softc->request_ccbs);
      TAILQ_INSERT_TAIL(&softc->request_ccbs, &request_ccb->ccb_h,
                    periph_links.tqe);
      softc->flags = 0;
      periph->softc = softc;
      cam_periph_acquire(periph);
      /*
       * Ensure we've waited at least a bus settle
       * delay before attempting to probe the device.
       * For HBAs that don't do bus resets, this won't make a difference.
       */
      cam_periph_freeze_after_event(periph, &periph->path->bus->last_reset,
                              scsi_delay);
      probeschedule(periph);
      return(CAM_REQ_CMP);
}

static void
probeschedule(struct cam_periph *periph)
{
      struct ccb_pathinq cpi;
      union ccb *ccb;
      probe_softc *softc;

      softc = (probe_softc *)periph->softc;
      ccb = (union ccb *)TAILQ_FIRST(&softc->request_ccbs);

      xpt_setup_ccb(&cpi.ccb_h, periph->path, /*priority*/1);
      cpi.ccb_h.func_code = XPT_PATH_INQ;
      xpt_action((union ccb *)&cpi);

      /*
       * If a device has gone away and another device, or the same one,
       * is back in the same place, it should have a unit attention
       * condition pending.  It will not report the unit attention in
       * response to an inquiry, which may leave invalid transfer
       * negotiations in effect.  The TUR will reveal the unit attention
       * condition.  Only send the TUR for lun 0, since some devices 
       * will get confused by commands other than inquiry to non-existent
       * luns.  If you think a device has gone away start your scan from
       * lun 0.  This will insure that any bogus transfer settings are
       * invalidated.
       *
       * If we haven't seen the device before and the controller supports
       * some kind of transfer negotiation, negotiate with the first
       * sent command if no bus reset was performed at startup.  This
       * ensures that the device is not confused by transfer negotiation
       * settings left over by loader or BIOS action.
       */
      if (((ccb->ccb_h.path->device->flags & CAM_DEV_UNCONFIGURED) == 0)
       && (ccb->ccb_h.target_lun == 0)) {
            softc->action = PROBE_TUR;
      } else if ((cpi.hba_inquiry & (PI_WIDE_32|PI_WIDE_16|PI_SDTR_ABLE)) != 0
            && (cpi.hba_misc & PIM_NOBUSRESET) != 0) {
            proberequestdefaultnegotiation(periph);
            softc->action = PROBE_INQUIRY;
      } else {
            softc->action = PROBE_INQUIRY;
      }

      if (ccb->crcn.flags & CAM_EXPECT_INQ_CHANGE)
            softc->flags |= PROBE_NO_ANNOUNCE;
      else
            softc->flags &= ~PROBE_NO_ANNOUNCE;

      xpt_schedule(periph, ccb->ccb_h.pinfo.priority);
}

static void
probestart(struct cam_periph *periph, union ccb *start_ccb)
{
      /* Probe the device that our peripheral driver points to */
      struct ccb_scsiio *csio;
      probe_softc *softc;

      CAM_DEBUG(start_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("probestart\n"));

      softc = (probe_softc *)periph->softc;
      csio = &start_ccb->csio;

      switch (softc->action) {
      case PROBE_TUR:
      case PROBE_TUR_FOR_NEGOTIATION:
      {
            scsi_test_unit_ready(csio,
                             /*retries*/4,
                             probedone,
                             MSG_SIMPLE_Q_TAG,
                             SSD_FULL_SIZE,
                             /*timeout*/60000);
            break;
      }
      case PROBE_INQUIRY:
      case PROBE_FULL_INQUIRY:
      {
            u_int inquiry_len;
            struct scsi_inquiry_data *inq_buf;

            inq_buf = &periph->path->device->inq_data;
            /*
             * If the device is currently configured, we calculate an
             * MD5 checksum of the inquiry data, and if the serial number
             * length is greater than 0, add the serial number data
             * into the checksum as well.  Once the inquiry and the
             * serial number check finish, we attempt to figure out
             * whether we still have the same device.
             */
            if ((periph->path->device->flags & CAM_DEV_UNCONFIGURED) == 0) {
                  
                  MD5Init(&softc->context);
                  MD5Update(&softc->context, (unsigned char *)inq_buf,
                          sizeof(struct scsi_inquiry_data));
                  softc->flags |= PROBE_INQUIRY_CKSUM;
                  if (periph->path->device->serial_num_len > 0) {
                        MD5Update(&softc->context,
                                periph->path->device->serial_num,
                                periph->path->device->serial_num_len);
                        softc->flags |= PROBE_SERIAL_CKSUM;
                  }
                  MD5Final(softc->digest, &softc->context);
            } 

            if (softc->action == PROBE_INQUIRY)
                  inquiry_len = SHORT_INQUIRY_LENGTH;
            else
                  inquiry_len = inq_buf->additional_length
                            + offsetof(struct scsi_inquiry_data,
                                               additional_length) + 1;

            /*
             * Some parallel SCSI devices fail to send an
             * ignore wide residue message when dealing with
             * odd length inquiry requests.  Round up to be
             * safe.
             */
            inquiry_len = roundup2(inquiry_len, 2);
      
            scsi_inquiry(csio,
                       /*retries*/4,
                       probedone,
                       MSG_SIMPLE_Q_TAG,
                       (u_int8_t *)inq_buf,
                       inquiry_len,
                       /*evpd*/FALSE,
                       /*page_code*/0,
                       SSD_MIN_SIZE,
                       /*timeout*/60 * 1000);
            break;
      }
      case PROBE_MODE_SENSE:
      {
            void  *mode_buf;
            int    mode_buf_len;

            mode_buf_len = sizeof(struct scsi_mode_header_6)
                       + sizeof(struct scsi_mode_blk_desc)
                       + sizeof(struct scsi_control_page);
            mode_buf = malloc(mode_buf_len, M_TEMP, M_NOWAIT);
            if (mode_buf != NULL) {
                      scsi_mode_sense(csio,
                              /*retries*/4,
                              probedone,
                              MSG_SIMPLE_Q_TAG,
                              /*dbd*/FALSE,
                              SMS_PAGE_CTRL_CURRENT,
                              SMS_CONTROL_MODE_PAGE,
                              mode_buf,
                              mode_buf_len,
                              SSD_FULL_SIZE,
                              /*timeout*/60000);
                  break;
            }
            xpt_print_path(periph->path);
            printf("Unable to mode sense control page - malloc failure\n");
            softc->action = PROBE_SERIAL_NUM;
      }
      /* FALLTHROUGH */
      case PROBE_SERIAL_NUM:
      {
            struct scsi_vpd_unit_serial_number *serial_buf;
            struct cam_ed* device;

            serial_buf = NULL;
            device = periph->path->device;
            device->serial_num = NULL;
            device->serial_num_len = 0;

            if ((device->quirk->quirks & CAM_QUIRK_NOSERIAL) == 0)
                  serial_buf = (struct scsi_vpd_unit_serial_number *)
                        malloc(sizeof(*serial_buf), M_TEMP,
                              M_NOWAIT | M_ZERO);

            if (serial_buf != NULL) {
                  scsi_inquiry(csio,
                             /*retries*/4,
                             probedone,
                             MSG_SIMPLE_Q_TAG,
                             (u_int8_t *)serial_buf,
                             sizeof(*serial_buf),
                             /*evpd*/TRUE,
                             SVPD_UNIT_SERIAL_NUMBER,
                             SSD_MIN_SIZE,
                             /*timeout*/60 * 1000);
                  break;
            }
            /*
             * We'll have to do without, let our probedone
             * routine finish up for us.
             */
            start_ccb->csio.data_ptr = NULL;
            probedone(periph, start_ccb);
            return;
      }
      }
      xpt_action(start_ccb);
}

static void
proberequestdefaultnegotiation(struct cam_periph *periph)
{
      struct ccb_trans_settings cts;

      xpt_setup_ccb(&cts.ccb_h, periph->path, /*priority*/1);
      cts.ccb_h.func_code = XPT_GET_TRAN_SETTINGS;
#ifdef CAM_NEW_TRAN_CODE
      cts.type = CTS_TYPE_USER_SETTINGS;
#else /* CAM_NEW_TRAN_CODE */
      cts.flags = CCB_TRANS_USER_SETTINGS;
#endif /* CAM_NEW_TRAN_CODE */
      xpt_action((union ccb *)&cts);
      cts.ccb_h.func_code = XPT_SET_TRAN_SETTINGS;
#ifdef CAM_NEW_TRAN_CODE
      cts.type = CTS_TYPE_CURRENT_SETTINGS;
#else /* CAM_NEW_TRAN_CODE */
      cts.flags &= ~CCB_TRANS_USER_SETTINGS;
      cts.flags |= CCB_TRANS_CURRENT_SETTINGS;
#endif /* CAM_NEW_TRAN_CODE */
      xpt_action((union ccb *)&cts);
}

static void
probedone(struct cam_periph *periph, union ccb *done_ccb)
{
      probe_softc *softc;
      struct cam_path *path;
      u_int32_t  priority;

      CAM_DEBUG(done_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("probedone\n"));

      softc = (probe_softc *)periph->softc;
      path = done_ccb->ccb_h.path;
      priority = done_ccb->ccb_h.pinfo.priority;

      switch (softc->action) {
      case PROBE_TUR:
      {
            if ((done_ccb->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {

                  if (cam_periph_error(done_ccb, 0,
                                   SF_NO_PRINT, NULL) == ERESTART)
                        return;
                  else if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                        /* Don't wedge the queue */
                        xpt_release_devq(done_ccb->ccb_h.path,
                                     /*count*/1,
                                     /*run_queue*/TRUE);
            }
            softc->action = PROBE_INQUIRY;
            xpt_release_ccb(done_ccb);
            xpt_schedule(periph, priority);
            return;
      }
      case PROBE_INQUIRY:
      case PROBE_FULL_INQUIRY:
      {
            if ((done_ccb->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP) {
                  struct scsi_inquiry_data *inq_buf;
                  u_int8_t periph_qual;

                  path->device->flags |= CAM_DEV_INQUIRY_DATA_VALID;
                  inq_buf = &path->device->inq_data;

                  periph_qual = SID_QUAL(inq_buf);
                  
                  switch(periph_qual) {
                  case SID_QUAL_LU_CONNECTED:
                  {
                        u_int8_t len;

                        /*
                         * We conservatively request only
                         * SHORT_INQUIRY_LEN bytes of inquiry
                         * information during our first try
                         * at sending an INQUIRY. If the device
                         * has more information to give,
                         * perform a second request specifying
                         * the amount of information the device
                         * is willing to give.
                         */
                        len = inq_buf->additional_length
                            + offsetof(struct scsi_inquiry_data,
                                               additional_length) + 1;
                        if (softc->action == PROBE_INQUIRY
                         && len > SHORT_INQUIRY_LENGTH) {
                              softc->action = PROBE_FULL_INQUIRY;
                              xpt_release_ccb(done_ccb);
                              xpt_schedule(periph, priority);
                              return;
                        }

                        xpt_find_quirk(path->device);

#ifdef CAM_NEW_TRAN_CODE
                        xpt_devise_transport(path);
#endif /* CAM_NEW_TRAN_CODE */
                        if (INQ_DATA_TQ_ENABLED(inq_buf))
                              softc->action = PROBE_MODE_SENSE;
                        else
                              softc->action = PROBE_SERIAL_NUM;

                        path->device->flags &= ~CAM_DEV_UNCONFIGURED;

                        xpt_release_ccb(done_ccb);
                        xpt_schedule(periph, priority);
                        return;
                  }
                  default:
                        break;
                  }
            } else if (cam_periph_error(done_ccb, 0,
                                  done_ccb->ccb_h.target_lun > 0
                                  ? SF_RETRY_UA|SF_QUIET_IR
                                  : SF_RETRY_UA,
                                  &softc->saved_ccb) == ERESTART) {
                  return;
            } else if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
                  /* Don't wedge the queue */
                  xpt_release_devq(done_ccb->ccb_h.path, /*count*/1,
                               /*run_queue*/TRUE);
            }
            /*
             * If we get to this point, we got an error status back
             * from the inquiry and the error status doesn't require
             * automatically retrying the command.  Therefore, the
             * inquiry failed.  If we had inquiry information before
             * for this device, but this latest inquiry command failed,
             * the device has probably gone away.  If this device isn't
             * already marked unconfigured, notify the peripheral
             * drivers that this device is no more.
             */
            if ((path->device->flags & CAM_DEV_UNCONFIGURED) == 0)
                  /* Send the async notification. */
                  xpt_async(AC_LOST_DEVICE, path, NULL);

            xpt_release_ccb(done_ccb);
            break;
      }
      case PROBE_MODE_SENSE:
      {
            struct ccb_scsiio *csio;
            struct scsi_mode_header_6 *mode_hdr;

            csio = &done_ccb->csio;
            mode_hdr = (struct scsi_mode_header_6 *)csio->data_ptr;
            if ((csio->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP) {
                  struct scsi_control_page *page;
                  u_int8_t *offset;

                  offset = ((u_int8_t *)&mode_hdr[1])
                      + mode_hdr->blk_desc_len;
                  page = (struct scsi_control_page *)offset;
                  path->device->queue_flags = page->queue_flags;
            } else if (cam_periph_error(done_ccb, 0,
                                  SF_RETRY_UA|SF_NO_PRINT,
                                  &softc->saved_ccb) == ERESTART) {
                  return;
            } else if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
                  /* Don't wedge the queue */
                  xpt_release_devq(done_ccb->ccb_h.path,
                               /*count*/1, /*run_queue*/TRUE);
            }
            xpt_release_ccb(done_ccb);
            free(mode_hdr, M_TEMP);
            softc->action = PROBE_SERIAL_NUM;
            xpt_schedule(periph, priority);
            return;
      }
      case PROBE_SERIAL_NUM:
      {
            struct ccb_scsiio *csio;
            struct scsi_vpd_unit_serial_number *serial_buf;
            u_int32_t  priority;
            int changed;
            int have_serialnum;

            changed = 1;
            have_serialnum = 0;
            csio = &done_ccb->csio;
            priority = done_ccb->ccb_h.pinfo.priority;
            serial_buf =
                (struct scsi_vpd_unit_serial_number *)csio->data_ptr;

            /* Clean up from previous instance of this device */
            if (path->device->serial_num != NULL) {
                  free(path->device->serial_num, M_CAMXPT);
                  path->device->serial_num = NULL;
                  path->device->serial_num_len = 0;
            }

            if (serial_buf == NULL) {
                  /*
                   * Don't process the command as it was never sent
                   */
            } else if ((csio->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP
                  && (serial_buf->length > 0)) {

                  have_serialnum = 1;
                  path->device->serial_num =
                        (u_int8_t *)malloc((serial_buf->length + 1),
                                       M_CAMXPT, M_NOWAIT);
                  if (path->device->serial_num != NULL) {
                        bcopy(serial_buf->serial_num,
                              path->device->serial_num,
                              serial_buf->length);
                        path->device->serial_num_len =
                            serial_buf->length;
                        path->device->serial_num[serial_buf->length]
                            = '\0';
                  }
            } else if (cam_periph_error(done_ccb, 0,
                                  SF_RETRY_UA|SF_NO_PRINT,
                                  &softc->saved_ccb) == ERESTART) {
                  return;
            } else if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
                  /* Don't wedge the queue */
                  xpt_release_devq(done_ccb->ccb_h.path, /*count*/1,
                               /*run_queue*/TRUE);
            }
            
            /*
             * Let's see if we have seen this device before.
             */
            if ((softc->flags & PROBE_INQUIRY_CKSUM) != 0) {
                  MD5_CTX context;
                  u_int8_t digest[16];

                  MD5Init(&context);
                  
                  MD5Update(&context,
                          (unsigned char *)&path->device->inq_data,
                          sizeof(struct scsi_inquiry_data));

                  if (have_serialnum)
                        MD5Update(&context, serial_buf->serial_num,
                                serial_buf->length);

                  MD5Final(digest, &context);
                  if (bcmp(softc->digest, digest, 16) == 0)
                        changed = 0;

                  /*
                   * XXX Do we need to do a TUR in order to ensure
                   *     that the device really hasn't changed???
                   */
                  if ((changed != 0)
                   && ((softc->flags & PROBE_NO_ANNOUNCE) == 0))
                        xpt_async(AC_LOST_DEVICE, path, NULL);
            }
            if (serial_buf != NULL)
                  free(serial_buf, M_TEMP);

            if (changed != 0) {
                  /*
                   * Now that we have all the necessary
                   * information to safely perform transfer
                   * negotiations... Controllers don't perform
                   * any negotiation or tagged queuing until
                   * after the first XPT_SET_TRAN_SETTINGS ccb is
                   * received.  So, on a new device, just retreive
                   * the user settings, and set them as the current
                   * settings to set the device up.
                   */
                  proberequestdefaultnegotiation(periph);
                  xpt_release_ccb(done_ccb);

                  /*
                   * Perform a TUR to allow the controller to
                   * perform any necessary transfer negotiation.
                   */
                  softc->action = PROBE_TUR_FOR_NEGOTIATION;
                  xpt_schedule(periph, priority);
                  return;
            }
            xpt_release_ccb(done_ccb);
            break;
      }
      case PROBE_TUR_FOR_NEGOTIATION:
            if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
                  /* Don't wedge the queue */
                  xpt_release_devq(done_ccb->ccb_h.path, /*count*/1,
                               /*run_queue*/TRUE);
            }

            path->device->flags &= ~CAM_DEV_UNCONFIGURED;

            if ((softc->flags & PROBE_NO_ANNOUNCE) == 0) {
                  /* Inform the XPT that a new device has been found */
                  done_ccb->ccb_h.func_code = XPT_GDEV_TYPE;
                  xpt_action(done_ccb);

                  xpt_async(AC_FOUND_DEVICE, done_ccb->ccb_h.path,
                          done_ccb);
            }
            xpt_release_ccb(done_ccb);
            break;
      }
      done_ccb = (union ccb *)TAILQ_FIRST(&softc->request_ccbs);
      TAILQ_REMOVE(&softc->request_ccbs, &done_ccb->ccb_h, periph_links.tqe);
      done_ccb->ccb_h.status = CAM_REQ_CMP;
      xpt_done(done_ccb);
      if (TAILQ_FIRST(&softc->request_ccbs) == NULL) {
            cam_periph_invalidate(periph);
            cam_periph_release(periph);
      } else {
            probeschedule(periph);
      }
}

static void
probecleanup(struct cam_periph *periph)
{
      free(periph->softc, M_TEMP);
}

static void
xpt_find_quirk(struct cam_ed *device)
{
      caddr_t     match;

      match = cam_quirkmatch((caddr_t)&device->inq_data,
                         (caddr_t)xpt_quirk_table,
                         sizeof(xpt_quirk_table)/sizeof(*xpt_quirk_table),
                         sizeof(*xpt_quirk_table), scsi_inquiry_match);

      if (match == NULL)
            panic("xpt_find_quirk: device didn't match wildcard entry!!");

      device->quirk = (struct xpt_quirk_entry *)match;
}

static int
sysctl_cam_search_luns(SYSCTL_HANDLER_ARGS)
{
      int error, bool;

      bool = cam_srch_hi;
      error = sysctl_handle_int(oidp, &bool, sizeof(bool), req);
      if (error != 0 || req->newptr == NULL)
            return (error);
      if (bool == 0 || bool == 1) {
            cam_srch_hi = bool;
            return (0);
      } else {
            return (EINVAL);
      }
}

#ifdef CAM_NEW_TRAN_CODE

static void
xpt_devise_transport(struct cam_path *path)
{
      struct ccb_pathinq cpi;
      struct ccb_trans_settings cts;
      struct scsi_inquiry_data *inq_buf;

      /* Get transport information from the SIM */
      xpt_setup_ccb(&cpi.ccb_h, path, /*priority*/1);
      cpi.ccb_h.func_code = XPT_PATH_INQ;
      xpt_action((union ccb *)&cpi);

      inq_buf = NULL;
      if ((path->device->flags & CAM_DEV_INQUIRY_DATA_VALID) != 0)
            inq_buf = &path->device->inq_data;
      path->device->protocol = PROTO_SCSI;
      path->device->protocol_version =
          inq_buf != NULL ? SID_ANSI_REV(inq_buf) : cpi.protocol_version;
      path->device->transport = cpi.transport;
      path->device->transport_version = cpi.transport_version;

      /*
       * Any device not using SPI3 features should
       * be considered SPI2 or lower.
       */
      if (inq_buf != NULL) {
            if (path->device->transport == XPORT_SPI
             && (inq_buf->spi3data & SID_SPI_MASK) == 0
             && path->device->transport_version > 2)
                  path->device->transport_version = 2;
      } else {
            struct cam_ed* otherdev;

            for (otherdev = TAILQ_FIRST(&path->target->ed_entries);
                 otherdev != NULL;
                 otherdev = TAILQ_NEXT(otherdev, links)) {
                  if (otherdev != path->device)
                        break;
            }
                
            if (otherdev != NULL) {
                  /*
                   * Initially assume the same versioning as
                   * prior luns for this target.
                   */
                  path->device->protocol_version =
                      otherdev->protocol_version;
                  path->device->transport_version =
                      otherdev->transport_version;
            } else {
                  /* Until we know better, opt for safty */
                  path->device->protocol_version = 2;
                  if (path->device->transport == XPORT_SPI)
                        path->device->transport_version = 2;
                  else
                        path->device->transport_version = 0;
            }
      }

      /*
       * XXX
       * For a device compliant with SPC-2 we should be able
       * to determine the transport version supported by
       * scrutinizing the version descriptors in the
       * inquiry buffer.
       */

      /* Tell the controller what we think */
      xpt_setup_ccb(&cts.ccb_h, path, /*priority*/1);
      cts.ccb_h.func_code = XPT_SET_TRAN_SETTINGS;
      cts.type = CTS_TYPE_CURRENT_SETTINGS;
      cts.transport = path->device->transport;
      cts.transport_version = path->device->transport_version;
      cts.protocol = path->device->protocol;
      cts.protocol_version = path->device->protocol_version;
      cts.proto_specific.valid = 0;
      cts.xport_specific.valid = 0;
      xpt_action((union ccb *)&cts);
}

static void
xpt_set_transfer_settings(struct ccb_trans_settings *cts, struct cam_ed *device,
                    int async_update)
{
      struct      ccb_pathinq cpi;
      struct      ccb_trans_settings cur_cts;
      struct      ccb_trans_settings_scsi *scsi;
      struct      ccb_trans_settings_scsi *cur_scsi;
      struct      cam_sim *sim;
      struct      scsi_inquiry_data *inq_data;

      if (device == NULL) {
            cts->ccb_h.status = CAM_PATH_INVALID;
            xpt_done((union ccb *)cts);
            return;
      }

      if (cts->protocol == PROTO_UNKNOWN
       || cts->protocol == PROTO_UNSPECIFIED) {
            cts->protocol = device->protocol;
            cts->protocol_version = device->protocol_version;
      }

      if (cts->protocol_version == PROTO_VERSION_UNKNOWN
       || cts->protocol_version == PROTO_VERSION_UNSPECIFIED)
            cts->protocol_version = device->protocol_version;

      if (cts->protocol != device->protocol) {
            xpt_print_path(cts->ccb_h.path);
            printf("Uninitialized Protocol %x:%x?\n",
                   cts->protocol, device->protocol);
            cts->protocol = device->protocol;
      }

      if (cts->protocol_version > device->protocol_version) {
            if (bootverbose) {
                  xpt_print_path(cts->ccb_h.path);
                  printf("Down reving Protocol Version from %d to %d?\n",
                         cts->protocol_version, device->protocol_version);
            }
            cts->protocol_version = device->protocol_version;
      }

      if (cts->transport == XPORT_UNKNOWN
       || cts->transport == XPORT_UNSPECIFIED) {
            cts->transport = device->transport;
            cts->transport_version = device->transport_version;
      }

      if (cts->transport_version == XPORT_VERSION_UNKNOWN
       || cts->transport_version == XPORT_VERSION_UNSPECIFIED)
            cts->transport_version = device->transport_version;

      if (cts->transport != device->transport) {
            xpt_print_path(cts->ccb_h.path);
            printf("Uninitialized Transport %x:%x?\n",
                   cts->transport, device->transport);
            cts->transport = device->transport;
      }

      if (cts->transport_version > device->transport_version) {
            if (bootverbose) {
                  xpt_print_path(cts->ccb_h.path);
                  printf("Down reving Transport Version from %d to %d?\n",
                         cts->transport_version,
                         device->transport_version);
            }
            cts->transport_version = device->transport_version;
      }

      sim = cts->ccb_h.path->bus->sim;

      /*
       * Nothing more of interest to do unless
       * this is a device connected via the
       * SCSI protocol.
       */
      if (cts->protocol != PROTO_SCSI) {
            if (async_update == FALSE) 
                  (*(sim->sim_action))(sim, (union ccb *)cts);
            return;
      }

      inq_data = &device->inq_data;
      scsi = &cts->proto_specific.scsi;
      xpt_setup_ccb(&cpi.ccb_h, cts->ccb_h.path, /*priority*/1);
      cpi.ccb_h.func_code = XPT_PATH_INQ;
      xpt_action((union ccb *)&cpi);

      /* SCSI specific sanity checking */
      if ((cpi.hba_inquiry & PI_TAG_ABLE) == 0
       || (INQ_DATA_TQ_ENABLED(inq_data)) == 0
       || (device->queue_flags & SCP_QUEUE_DQUE) != 0
       || (device->quirk->mintags == 0)) {
            /*
             * Can't tag on hardware that doesn't support tags,
             * doesn't have it enabled, or has broken tag support.
             */
            scsi->flags &= ~CTS_SCSI_FLAGS_TAG_ENB;
      }

      if (async_update == FALSE) {
            /*
             * Perform sanity checking against what the
             * controller and device can do.
             */
            xpt_setup_ccb(&cur_cts.ccb_h, cts->ccb_h.path, /*priority*/1);
            cur_cts.ccb_h.func_code = XPT_GET_TRAN_SETTINGS;
            cur_cts.type = cts->type;
            xpt_action((union ccb *)&cur_cts);

            cur_scsi = &cur_cts.proto_specific.scsi;
            if ((scsi->valid & CTS_SCSI_VALID_TQ) == 0) {
                  scsi->flags &= ~CTS_SCSI_FLAGS_TAG_ENB;
                  scsi->flags |= cur_scsi->flags & CTS_SCSI_FLAGS_TAG_ENB;
            }
            if ((cur_scsi->valid & CTS_SCSI_VALID_TQ) == 0)
                  scsi->flags &= ~CTS_SCSI_FLAGS_TAG_ENB;
      }

      /* SPI specific sanity checking */
      if (cts->transport == XPORT_SPI && async_update == FALSE) {
            u_int spi3caps;
            struct ccb_trans_settings_spi *spi;
            struct ccb_trans_settings_spi *cur_spi;

            spi = &cts->xport_specific.spi;

            cur_spi = &cur_cts.xport_specific.spi;

            /* Fill in any gaps in what the user gave us */
            if ((spi->valid & CTS_SPI_VALID_SYNC_RATE) == 0)
                  spi->sync_period = cur_spi->sync_period;
            if ((cur_spi->valid & CTS_SPI_VALID_SYNC_RATE) == 0)
                  spi->sync_period = 0;
            if ((spi->valid & CTS_SPI_VALID_SYNC_OFFSET) == 0)
                  spi->sync_offset = cur_spi->sync_offset;
            if ((cur_spi->valid & CTS_SPI_VALID_SYNC_OFFSET) == 0)
                  spi->sync_offset = 0;
            if ((spi->valid & CTS_SPI_VALID_PPR_OPTIONS) == 0)
                  spi->ppr_options = cur_spi->ppr_options;
            if ((cur_spi->valid & CTS_SPI_VALID_PPR_OPTIONS) == 0)
                  spi->ppr_options = 0;
            if ((spi->valid & CTS_SPI_VALID_BUS_WIDTH) == 0)
                  spi->bus_width = cur_spi->bus_width;
            if ((cur_spi->valid & CTS_SPI_VALID_BUS_WIDTH) == 0)
                  spi->bus_width = 0;
            if ((spi->valid & CTS_SPI_VALID_DISC) == 0) {
                  spi->flags &= ~CTS_SPI_FLAGS_DISC_ENB;
                  spi->flags |= cur_spi->flags & CTS_SPI_FLAGS_DISC_ENB;
            }
            if ((cur_spi->valid & CTS_SPI_VALID_DISC) == 0)
                  spi->flags &= ~CTS_SPI_FLAGS_DISC_ENB;
            if (((device->flags & CAM_DEV_INQUIRY_DATA_VALID) != 0
              && (inq_data->flags & SID_Sync) == 0
              && cts->type == CTS_TYPE_CURRENT_SETTINGS)
             || ((cpi.hba_inquiry & PI_SDTR_ABLE) == 0)
             || (cur_spi->sync_offset == 0)
             || (cur_spi->sync_period == 0)) {
                  /* Force async */
                  spi->sync_period = 0;
                  spi->sync_offset = 0;
            }

            switch (spi->bus_width) {
            case MSG_EXT_WDTR_BUS_32_BIT:
                  if (((device->flags & CAM_DEV_INQUIRY_DATA_VALID) == 0
                    || (inq_data->flags & SID_WBus32) != 0
                    || cts->type == CTS_TYPE_USER_SETTINGS)
                   && (cpi.hba_inquiry & PI_WIDE_32) != 0)
                        break;
                  /* Fall Through to 16-bit */
            case MSG_EXT_WDTR_BUS_16_BIT:
                  if (((device->flags & CAM_DEV_INQUIRY_DATA_VALID) == 0
                    || (inq_data->flags & SID_WBus16) != 0
                    || cts->type == CTS_TYPE_USER_SETTINGS)
                   && (cpi.hba_inquiry & PI_WIDE_16) != 0) {
                        spi->bus_width = MSG_EXT_WDTR_BUS_16_BIT;
                        break;
                  }
                  /* Fall Through to 8-bit */
            default: /* New bus width?? */
            case MSG_EXT_WDTR_BUS_8_BIT:
                  /* All targets can do this */
                  spi->bus_width = MSG_EXT_WDTR_BUS_8_BIT;
                  break;
            }

            spi3caps = cpi.xport_specific.spi.ppr_options;
            if ((device->flags & CAM_DEV_INQUIRY_DATA_VALID) != 0
             && cts->type == CTS_TYPE_CURRENT_SETTINGS)
                  spi3caps &= inq_data->spi3data;

            if ((spi3caps & SID_SPI_CLOCK_DT) == 0)
                  spi->ppr_options &= ~MSG_EXT_PPR_DT_REQ;

            if ((spi3caps & SID_SPI_IUS) == 0)
                  spi->ppr_options &= ~MSG_EXT_PPR_IU_REQ;

            if ((spi3caps & SID_SPI_QAS) == 0)
                  spi->ppr_options &= ~MSG_EXT_PPR_QAS_REQ;

            /* No SPI Transfer settings are allowed unless we are wide */
            if (spi->bus_width == 0)
                  spi->ppr_options = 0;

            if ((spi->flags & CTS_SPI_FLAGS_DISC_ENB) == 0) {
                  /*
                   * Can't tag queue without disconnection.
                   */
                  scsi->flags &= ~CTS_SCSI_FLAGS_TAG_ENB;
                  scsi->valid |= CTS_SCSI_VALID_TQ;
            }

            /*
             * If we are currently performing tagged transactions to
             * this device and want to change its negotiation parameters,
             * go non-tagged for a bit to give the controller a chance to
             * negotiate unhampered by tag messages.
             */
            if (cts->type == CTS_TYPE_CURRENT_SETTINGS
             && (device->inq_flags & SID_CmdQue) != 0
             && (scsi->flags & CTS_SCSI_FLAGS_TAG_ENB) != 0
             && (spi->flags & (CTS_SPI_VALID_SYNC_RATE|
                           CTS_SPI_VALID_SYNC_OFFSET|
                           CTS_SPI_VALID_BUS_WIDTH)) != 0)
                  xpt_toggle_tags(cts->ccb_h.path);
      }

      if (cts->type == CTS_TYPE_CURRENT_SETTINGS
       && (scsi->valid & CTS_SCSI_VALID_TQ) != 0) {
            int device_tagenb;

            /*
             * If we are transitioning from tags to no-tags or
             * vice-versa, we need to carefully freeze and restart
             * the queue so that we don't overlap tagged and non-tagged
             * commands.  We also temporarily stop tags if there is
             * a change in transfer negotiation settings to allow
             * "tag-less" negotiation.
             */
            if ((device->flags & CAM_DEV_TAG_AFTER_COUNT) != 0
             || (device->inq_flags & SID_CmdQue) != 0)
                  device_tagenb = TRUE;
            else
                  device_tagenb = FALSE;

            if (((scsi->flags & CTS_SCSI_FLAGS_TAG_ENB) != 0
              && device_tagenb == FALSE)
             || ((scsi->flags & CTS_SCSI_FLAGS_TAG_ENB) == 0
              && device_tagenb == TRUE)) {

                  if ((scsi->flags & CTS_SCSI_FLAGS_TAG_ENB) != 0) {
                        /*
                         * Delay change to use tags until after a
                         * few commands have gone to this device so
                         * the controller has time to perform transfer
                         * negotiations without tagged messages getting
                         * in the way.
                         */
                        device->tag_delay_count = CAM_TAG_DELAY_COUNT;
                        device->flags |= CAM_DEV_TAG_AFTER_COUNT;
                  } else {
                        struct ccb_relsim crs;

                        xpt_freeze_devq(cts->ccb_h.path, /*count*/1);
                        device->inq_flags &= ~SID_CmdQue;
                        xpt_dev_ccbq_resize(cts->ccb_h.path,
                                        sim->max_dev_openings);
                        device->flags &= ~CAM_DEV_TAG_AFTER_COUNT;
                        device->tag_delay_count = 0;

                        xpt_setup_ccb(&crs.ccb_h, cts->ccb_h.path,
                                    /*priority*/1);
                        crs.ccb_h.func_code = XPT_REL_SIMQ;
                        crs.release_flags = RELSIM_RELEASE_AFTER_QEMPTY;
                        crs.openings
                            = crs.release_timeout 
                            = crs.qfrozen_cnt
                            = 0;
                        xpt_action((union ccb *)&crs);
                  }
            }
      }
      if (async_update == FALSE) 
            (*(sim->sim_action))(sim, (union ccb *)cts);
}

#else /* CAM_NEW_TRAN_CODE */

static void
xpt_set_transfer_settings(struct ccb_trans_settings *cts, struct cam_ed *device,
                    int async_update)
{
      struct      cam_sim *sim;
      int   qfrozen;

      sim = cts->ccb_h.path->bus->sim;
      if (async_update == FALSE) {
            struct      scsi_inquiry_data *inq_data;
            struct      ccb_pathinq cpi;
            struct      ccb_trans_settings cur_cts;

            if (device == NULL) {
                  cts->ccb_h.status = CAM_PATH_INVALID;
                  xpt_done((union ccb *)cts);
                  return;
            }

            /*
             * Perform sanity checking against what the
             * controller and device can do.
             */
            xpt_setup_ccb(&cpi.ccb_h, cts->ccb_h.path, /*priority*/1);
            cpi.ccb_h.func_code = XPT_PATH_INQ;
            xpt_action((union ccb *)&cpi);
            xpt_setup_ccb(&cur_cts.ccb_h, cts->ccb_h.path, /*priority*/1);
            cur_cts.ccb_h.func_code = XPT_GET_TRAN_SETTINGS;
            cur_cts.flags = CCB_TRANS_CURRENT_SETTINGS;
            xpt_action((union ccb *)&cur_cts);
            inq_data = &device->inq_data;

            /* Fill in any gaps in what the user gave us */
            if ((cts->valid & CCB_TRANS_SYNC_RATE_VALID) == 0)
                  cts->sync_period = cur_cts.sync_period;
            if ((cts->valid & CCB_TRANS_SYNC_OFFSET_VALID) == 0)
                  cts->sync_offset = cur_cts.sync_offset;
            if ((cts->valid & CCB_TRANS_BUS_WIDTH_VALID) == 0)
                  cts->bus_width = cur_cts.bus_width;
            if ((cts->valid & CCB_TRANS_DISC_VALID) == 0) {
                  cts->flags &= ~CCB_TRANS_DISC_ENB;
                  cts->flags |= cur_cts.flags & CCB_TRANS_DISC_ENB;
            }
            if ((cts->valid & CCB_TRANS_TQ_VALID) == 0) {
                  cts->flags &= ~CCB_TRANS_TAG_ENB;
                  cts->flags |= cur_cts.flags & CCB_TRANS_TAG_ENB;
            }

            if (((device->flags & CAM_DEV_INQUIRY_DATA_VALID) != 0
              && (inq_data->flags & SID_Sync) == 0)
             || ((cpi.hba_inquiry & PI_SDTR_ABLE) == 0)
             || (cts->sync_offset == 0)
             || (cts->sync_period == 0)) {
                  /* Force async */
                  cts->sync_period = 0;
                  cts->sync_offset = 0;
            } else if ((device->flags & CAM_DEV_INQUIRY_DATA_VALID) != 0
                  && (inq_data->spi3data & SID_SPI_CLOCK_DT) == 0
                  && cts->sync_period <= 0x9) {
                  /*
                   * Don't allow DT transmission rates if the
                   * device does not support it.
                   */
                  cts->sync_period = 0xa;
            }

            switch (cts->bus_width) {
            case MSG_EXT_WDTR_BUS_32_BIT:
                  if (((device->flags & CAM_DEV_INQUIRY_DATA_VALID) == 0
                    || (inq_data->flags & SID_WBus32) != 0)
                   && (cpi.hba_inquiry & PI_WIDE_32) != 0)
                        break;
                  /* FALLTHROUGH to 16-bit */
            case MSG_EXT_WDTR_BUS_16_BIT:
                  if (((device->flags & CAM_DEV_INQUIRY_DATA_VALID) == 0
                    || (inq_data->flags & SID_WBus16) != 0)
                   && (cpi.hba_inquiry & PI_WIDE_16) != 0) {
                        cts->bus_width = MSG_EXT_WDTR_BUS_16_BIT;
                        break;
                  }
                  /* FALLTHROUGH to 8-bit */
            default: /* New bus width?? */
            case MSG_EXT_WDTR_BUS_8_BIT:
                  /* All targets can do this */
                  cts->bus_width = MSG_EXT_WDTR_BUS_8_BIT;
                  break;
            }

            if ((cts->flags & CCB_TRANS_DISC_ENB) == 0) {
                  /*
                   * Can't tag queue without disconnection.
                   */
                  cts->flags &= ~CCB_TRANS_TAG_ENB;
                  cts->valid |= CCB_TRANS_TQ_VALID;
            }

            if ((cpi.hba_inquiry & PI_TAG_ABLE) == 0
             || (INQ_DATA_TQ_ENABLED(inq_data)) == 0
             || (device->queue_flags & SCP_QUEUE_DQUE) != 0
             || (device->quirk->mintags == 0)) {
                  /*
                   * Can't tag on hardware that doesn't support,
                   * doesn't have it enabled, or has broken tag support.
                   */
                  cts->flags &= ~CCB_TRANS_TAG_ENB;
            }
      }

      qfrozen = FALSE;
      if ((cts->valid & CCB_TRANS_TQ_VALID) != 0) {
            int device_tagenb;

            /*
             * If we are transitioning from tags to no-tags or
             * vice-versa, we need to carefully freeze and restart
             * the queue so that we don't overlap tagged and non-tagged
             * commands.  We also temporarily stop tags if there is
             * a change in transfer negotiation settings to allow
             * "tag-less" negotiation.
             */
            if ((device->flags & CAM_DEV_TAG_AFTER_COUNT) != 0
             || (device->inq_flags & SID_CmdQue) != 0)
                  device_tagenb = TRUE;
            else
                  device_tagenb = FALSE;

            if (((cts->flags & CCB_TRANS_TAG_ENB) != 0
              && device_tagenb == FALSE)
             || ((cts->flags & CCB_TRANS_TAG_ENB) == 0
              && device_tagenb == TRUE)) {

                  if ((cts->flags & CCB_TRANS_TAG_ENB) != 0) {
                        /*
                         * Delay change to use tags until after a
                         * few commands have gone to this device so
                         * the controller has time to perform transfer
                         * negotiations without tagged messages getting
                         * in the way.
                         */
                        device->tag_delay_count = CAM_TAG_DELAY_COUNT;
                        device->flags |= CAM_DEV_TAG_AFTER_COUNT;
                  } else {
                        xpt_freeze_devq(cts->ccb_h.path, /*count*/1);
                        qfrozen = TRUE;
                        device->inq_flags &= ~SID_CmdQue;
                        xpt_dev_ccbq_resize(cts->ccb_h.path,
                                        sim->max_dev_openings);
                        device->flags &= ~CAM_DEV_TAG_AFTER_COUNT;
                        device->tag_delay_count = 0;
                  }
            }
      }

      if (async_update == FALSE) {
            /*
             * If we are currently performing tagged transactions to
             * this device and want to change its negotiation parameters,
             * go non-tagged for a bit to give the controller a chance to
             * negotiate unhampered by tag messages.
             */
            if ((device->inq_flags & SID_CmdQue) != 0
             && (cts->flags & (CCB_TRANS_SYNC_RATE_VALID|
                           CCB_TRANS_SYNC_OFFSET_VALID|
                           CCB_TRANS_BUS_WIDTH_VALID)) != 0)
                  xpt_toggle_tags(cts->ccb_h.path);

            (*(sim->sim_action))(sim, (union ccb *)cts);
      }

      if (qfrozen) {
            struct ccb_relsim crs;

            xpt_setup_ccb(&crs.ccb_h, cts->ccb_h.path,
                        /*priority*/1);
            crs.ccb_h.func_code = XPT_REL_SIMQ;
            crs.release_flags = RELSIM_RELEASE_AFTER_QEMPTY;
            crs.openings
                = crs.release_timeout 
                = crs.qfrozen_cnt
                = 0;
            xpt_action((union ccb *)&crs);
      }
}


#endif /* CAM_NEW_TRAN_CODE */

static void
xpt_toggle_tags(struct cam_path *path)
{
      struct cam_ed *dev;

      /*
       * Give controllers a chance to renegotiate
       * before starting tag operations.  We
       * "toggle" tagged queuing off then on
       * which causes the tag enable command delay
       * counter to come into effect.
       */
      dev = path->device;
      if ((dev->flags & CAM_DEV_TAG_AFTER_COUNT) != 0
       || ((dev->inq_flags & SID_CmdQue) != 0
        && (dev->inq_flags & (SID_Sync|SID_WBus16|SID_WBus32)) != 0)) {
            struct ccb_trans_settings cts;

            xpt_setup_ccb(&cts.ccb_h, path, 1);
#ifdef CAM_NEW_TRAN_CODE
            cts.protocol = PROTO_SCSI;
            cts.protocol_version = PROTO_VERSION_UNSPECIFIED;
            cts.transport = XPORT_UNSPECIFIED;
            cts.transport_version = XPORT_VERSION_UNSPECIFIED;
            cts.proto_specific.scsi.flags = 0;
            cts.proto_specific.scsi.valid = CTS_SCSI_VALID_TQ;
#else /* CAM_NEW_TRAN_CODE */
            cts.flags = 0;
            cts.valid = CCB_TRANS_TQ_VALID;
#endif /* CAM_NEW_TRAN_CODE */
            xpt_set_transfer_settings(&cts, path->device,
                                /*async_update*/TRUE);
#ifdef CAM_NEW_TRAN_CODE
            cts.proto_specific.scsi.flags = CTS_SCSI_FLAGS_TAG_ENB;
#else /* CAM_NEW_TRAN_CODE */
            cts.flags = CCB_TRANS_TAG_ENB;
#endif /* CAM_NEW_TRAN_CODE */
            xpt_set_transfer_settings(&cts, path->device,
                                /*async_update*/TRUE);
      }
}

static void
xpt_start_tags(struct cam_path *path)
{
      struct ccb_relsim crs;
      struct cam_ed *device;
      struct cam_sim *sim;
      int    newopenings;

      device = path->device;
      sim = path->bus->sim;
      device->flags &= ~CAM_DEV_TAG_AFTER_COUNT;
      xpt_freeze_devq(path, /*count*/1);
      device->inq_flags |= SID_CmdQue;
      if (device->tag_saved_openings != 0)
            newopenings = device->tag_saved_openings;
      else
            newopenings = min(device->quirk->maxtags,
                          sim->max_tagged_dev_openings);
      xpt_dev_ccbq_resize(path, newopenings);
      xpt_setup_ccb(&crs.ccb_h, path, /*priority*/1);
      crs.ccb_h.func_code = XPT_REL_SIMQ;
      crs.release_flags = RELSIM_RELEASE_AFTER_QEMPTY;
      crs.openings
          = crs.release_timeout 
          = crs.qfrozen_cnt
          = 0;
      xpt_action((union ccb *)&crs);
}

static int busses_to_config;
static int busses_to_reset;

static int
xptconfigbuscountfunc(struct cam_eb *bus, void *arg)
{
      if (bus->path_id != CAM_XPT_PATH_ID) {
            struct cam_path path;
            struct ccb_pathinq cpi;
            int can_negotiate;

            busses_to_config++;
            xpt_compile_path(&path, NULL, bus->path_id,
                         CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
            xpt_setup_ccb(&cpi.ccb_h, &path, /*priority*/1);
            cpi.ccb_h.func_code = XPT_PATH_INQ;
            xpt_action((union ccb *)&cpi);
            can_negotiate = cpi.hba_inquiry;
            can_negotiate &= (PI_WIDE_32|PI_WIDE_16|PI_SDTR_ABLE);
            if ((cpi.hba_misc & PIM_NOBUSRESET) == 0
             && can_negotiate)
                  busses_to_reset++;
            xpt_release_path(&path);
      }

      return(1);
}

static int
xptconfigfunc(struct cam_eb *bus, void *arg)
{
      struct      cam_path *path;
      union ccb *work_ccb;

      if (bus->path_id != CAM_XPT_PATH_ID) {
            cam_status status;
            int can_negotiate;

            work_ccb = xpt_alloc_ccb();
            if ((status = xpt_create_path(&path, xpt_periph, bus->path_id,
                                    CAM_TARGET_WILDCARD,
                                    CAM_LUN_WILDCARD)) !=CAM_REQ_CMP){
                  printf("xptconfigfunc: xpt_create_path failed with "
                         "status %#x for bus %d\n", status, bus->path_id);
                  printf("xptconfigfunc: halting bus configuration\n");
                  xpt_free_ccb(work_ccb);
                  busses_to_config--;
                  xpt_finishconfig(xpt_periph, NULL);
                  return(0);
            }
            xpt_setup_ccb(&work_ccb->ccb_h, path, /*priority*/1);
            work_ccb->ccb_h.func_code = XPT_PATH_INQ;
            xpt_action(work_ccb);
            if (work_ccb->ccb_h.status != CAM_REQ_CMP) {
                  printf("xptconfigfunc: CPI failed on bus %d "
                         "with status %d\n", bus->path_id,
                         work_ccb->ccb_h.status);
                  xpt_finishconfig(xpt_periph, work_ccb);
                  return(1);
            }

            can_negotiate = work_ccb->cpi.hba_inquiry;
            can_negotiate &= (PI_WIDE_32|PI_WIDE_16|PI_SDTR_ABLE);
            if ((work_ccb->cpi.hba_misc & PIM_NOBUSRESET) == 0
             && (can_negotiate != 0)) {
                  xpt_setup_ccb(&work_ccb->ccb_h, path, /*priority*/1);
                  work_ccb->ccb_h.func_code = XPT_RESET_BUS;
                  work_ccb->ccb_h.cbfcnp = NULL;
                  CAM_DEBUG(path, CAM_DEBUG_SUBTRACE,
                          ("Resetting Bus\n"));
                  xpt_action(work_ccb);
                  xpt_finishconfig(xpt_periph, work_ccb);
            } else {
                  /* Act as though we performed a successful BUS RESET */
                  work_ccb->ccb_h.func_code = XPT_RESET_BUS;
                  xpt_finishconfig(xpt_periph, work_ccb);
            }
      }

      return(1);
}

static void
xpt_config(void *arg)
{
      /*
       * Now that interrupts are enabled, go find our devices
       */

#ifdef CAMDEBUG
      /* Setup debugging flags and path */
#ifdef CAM_DEBUG_FLAGS
      cam_dflags = CAM_DEBUG_FLAGS;
#else /* !CAM_DEBUG_FLAGS */
      cam_dflags = CAM_DEBUG_NONE;
#endif /* CAM_DEBUG_FLAGS */
#ifdef CAM_DEBUG_BUS
      if (cam_dflags != CAM_DEBUG_NONE) {
            if (xpt_create_path(&cam_dpath, xpt_periph,
                            CAM_DEBUG_BUS, CAM_DEBUG_TARGET,
                            CAM_DEBUG_LUN) != CAM_REQ_CMP) {
                  printf("xpt_config: xpt_create_path() failed for debug"
                         " target %d:%d:%d, debugging disabled\n",
                         CAM_DEBUG_BUS, CAM_DEBUG_TARGET, CAM_DEBUG_LUN);
                  cam_dflags = CAM_DEBUG_NONE;
            }
      } else
            cam_dpath = NULL;
#else /* !CAM_DEBUG_BUS */
      cam_dpath = NULL;
#endif /* CAM_DEBUG_BUS */
#endif /* CAMDEBUG */

      /*
       * Scan all installed busses.
       */
      xpt_for_all_busses(xptconfigbuscountfunc, NULL);

      if (busses_to_config == 0) {
            /* Call manually because we don't have any busses */
            xpt_finishconfig(xpt_periph, NULL);
      } else  {
            if (busses_to_reset > 0 && scsi_delay >= 2000) {
                  printf("Waiting %d seconds for SCSI "
                         "devices to settle\n", scsi_delay/1000);
            }
            xpt_for_all_busses(xptconfigfunc, NULL);
      }
}

/*
 * If the given device only has one peripheral attached to it, and if that
 * peripheral is the passthrough driver, announce it.  This insures that the
 * user sees some sort of announcement for every peripheral in their system.
 */
static int
xptpassannouncefunc(struct cam_ed *device, void *arg)
{
      struct cam_periph *periph;
      int i;

      for (periph = SLIST_FIRST(&device->periphs), i = 0; periph != NULL;
           periph = SLIST_NEXT(periph, periph_links), i++);

      periph = SLIST_FIRST(&device->periphs);
      if ((i == 1)
       && (strncmp(periph->periph_name, "pass", 4) == 0))
            xpt_announce_periph(periph, NULL);

      return(1);
}

static void
xpt_finishconfig(struct cam_periph *periph, union ccb *done_ccb)
{
      struct      periph_driver **p_drv;
      int   i;

      if (done_ccb != NULL) {
            CAM_DEBUG(done_ccb->ccb_h.path, CAM_DEBUG_TRACE,
                    ("xpt_finishconfig\n"));
            switch(done_ccb->ccb_h.func_code) {
            case XPT_RESET_BUS:
                  if (done_ccb->ccb_h.status == CAM_REQ_CMP) {
                        done_ccb->ccb_h.func_code = XPT_SCAN_BUS;
                        done_ccb->ccb_h.cbfcnp = xpt_finishconfig;
                        done_ccb->crcn.flags = 0;
                        xpt_action(done_ccb);
                        return;
                  }
                  /* FALLTHROUGH */
            case XPT_SCAN_BUS:
            default:
                  xpt_free_path(done_ccb->ccb_h.path);
                  busses_to_config--;
                  break;
            }
      }

      if (busses_to_config == 0) {
            /* Register all the peripheral drivers */
            /* XXX This will have to change when we have loadable modules */
            p_drv = periph_drivers;
            for (i = 0; p_drv[i] != NULL; i++) {
                  (*p_drv[i]->init)();
            }

            /*
             * Check for devices with no "standard" peripheral driver
             * attached.  For any devices like that, announce the
             * passthrough driver so the user will see something.
             */
            xpt_for_all_devices(xptpassannouncefunc, NULL);

            /* Release our hook so that the boot can continue. */
            config_intrhook_disestablish(xpt_config_hook);
            free(xpt_config_hook, M_TEMP);
            xpt_config_hook = NULL;
      }
      if (done_ccb != NULL)
            xpt_free_ccb(done_ccb);
}

static void
xptaction(struct cam_sim *sim, union ccb *work_ccb)
{
      CAM_DEBUG(work_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("xptaction\n"));

      switch (work_ccb->ccb_h.func_code) {
      /* Common cases first */
      case XPT_PATH_INQ:            /* Path routing inquiry */
      {
            struct ccb_pathinq *cpi;

            cpi = &work_ccb->cpi;
            cpi->version_num = 1; /* XXX??? */
            cpi->hba_inquiry = 0;
            cpi->target_sprt = 0;
            cpi->hba_misc = 0;
            cpi->hba_eng_cnt = 0;
            cpi->max_target = 0;
            cpi->max_lun = 0;
            cpi->initiator_id = 0;
            strncpy(cpi->sim_vid, "FreeBSD", SIM_IDLEN);
            strncpy(cpi->hba_vid, "", HBA_IDLEN);
            strncpy(cpi->dev_name, sim->sim_name, DEV_IDLEN);
            cpi->unit_number = sim->unit_number;
            cpi->bus_id = sim->bus_id;
            cpi->base_transfer_speed = 0;
#ifdef CAM_NEW_TRAN_CODE
            cpi->protocol = PROTO_UNSPECIFIED;
            cpi->protocol_version = PROTO_VERSION_UNSPECIFIED;
            cpi->transport = XPORT_UNSPECIFIED;
            cpi->transport_version = XPORT_VERSION_UNSPECIFIED;
#endif /* CAM_NEW_TRAN_CODE */
            cpi->ccb_h.status = CAM_REQ_CMP;
            xpt_done(work_ccb);
            break;
      }
      default:
            work_ccb->ccb_h.status = CAM_REQ_INVALID;
            xpt_done(work_ccb);
            break;
      }
}

/*
 * The xpt as a "controller" has no interrupt sources, so polling
 * is a no-op.
 */
static void
xptpoll(struct cam_sim *sim)
{
}

static void
camisr(void *V_queue)
{
      cam_isrq_t *oqueue = V_queue;
      cam_isrq_t queue;
      int   s;
      struct      ccb_hdr *ccb_h;

      /*
       * Transfer the ccb_bioq list to a temporary list so we can operate
       * on it without needing to lock/unlock on every loop.  The concat
       * function with re-init the real list for us.
       */
      s = splcam();
      mtx_lock(&cam_bioq_lock);
      TAILQ_INIT(&queue);
      TAILQ_CONCAT(&queue, oqueue, sim_links.tqe);
      mtx_unlock(&cam_bioq_lock);

      while ((ccb_h = TAILQ_FIRST(&queue)) != NULL) {
            int   runq;

            TAILQ_REMOVE(&queue, ccb_h, sim_links.tqe);
            ccb_h->pinfo.index = CAM_UNQUEUED_INDEX;
            splx(s);

            CAM_DEBUG(ccb_h->path, CAM_DEBUG_TRACE,
                    ("camisr\n"));

            runq = FALSE;

            if (ccb_h->flags & CAM_HIGH_POWER) {
                  struct highpowerlist    *hphead;
                  union ccb         *send_ccb;

                  hphead = &highpowerq;

                  send_ccb = (union ccb *)STAILQ_FIRST(hphead);

                  /*
                   * Increment the count since this command is done.
                   */
                  num_highpower++;

                  /* 
                   * Any high powered commands queued up?
                   */
                  if (send_ccb != NULL) {

                        STAILQ_REMOVE_HEAD(hphead, xpt_links.stqe);

                        xpt_release_devq(send_ccb->ccb_h.path,
                                     /*count*/1, /*runqueue*/TRUE);
                  }
            }
            if ((ccb_h->func_code & XPT_FC_USER_CCB) == 0) {
                  struct cam_ed *dev;

                  dev = ccb_h->path->device;

                  s = splcam();
                  cam_ccbq_ccb_done(&dev->ccbq, (union ccb *)ccb_h);

                  if (!SIM_DEAD(ccb_h->path->bus->sim)) {
                        ccb_h->path->bus->sim->devq->send_active--;
                        ccb_h->path->bus->sim->devq->send_openings++;
                  }
                  splx(s);
                  
                  if (((dev->flags & CAM_DEV_REL_ON_COMPLETE) != 0
                    && (ccb_h->status&CAM_STATUS_MASK) != CAM_REQUEUE_REQ)
                   || ((dev->flags & CAM_DEV_REL_ON_QUEUE_EMPTY) != 0
                    && (dev->ccbq.dev_active == 0))) {
                        
                        xpt_release_devq(ccb_h->path, /*count*/1,
                                     /*run_queue*/TRUE);
                  }

                  if ((dev->flags & CAM_DEV_TAG_AFTER_COUNT) != 0
                   && (--dev->tag_delay_count == 0))
                        xpt_start_tags(ccb_h->path);

                  if ((dev->ccbq.queue.entries > 0)
                   && (dev->qfrozen_cnt == 0)
                   && (device_is_send_queued(dev) == 0)) {
                        runq = xpt_schedule_dev_sendq(ccb_h->path->bus,
                                                dev);
                  }
            }

            if (ccb_h->status & CAM_RELEASE_SIMQ) {
                  xpt_release_simq(ccb_h->path->bus->sim,
                               /*run_queue*/TRUE);
                  ccb_h->status &= ~CAM_RELEASE_SIMQ;
                  runq = FALSE;
            } 

            if ((ccb_h->flags & CAM_DEV_QFRZDIS)
             && (ccb_h->status & CAM_DEV_QFRZN)) {
                  xpt_release_devq(ccb_h->path, /*count*/1,
                               /*run_queue*/TRUE);
                  ccb_h->status &= ~CAM_DEV_QFRZN;
            } else if (runq) {
                  xpt_run_dev_sendq(ccb_h->path->bus);
            }

            /* Call the peripheral driver's callback */
            (*ccb_h->cbfcnp)(ccb_h->path->periph, (union ccb *)ccb_h);

            /* Raise IPL for while test */
            s = splcam();
      }
      splx(s);
}

static void
dead_sim_action(struct cam_sim *sim, union ccb *ccb)
{

      ccb->ccb_h.status = CAM_DEV_NOT_THERE;
      xpt_done(ccb);
}
 
static void
dead_sim_poll(struct cam_sim *sim)
{
}

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