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if_em.c

/**************************************************************************

Copyright (c) 2001-2007, Intel Corporation
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.

 2. Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.

 3. Neither the name of the Intel Corporation nor the names of its
    contributors may be used to endorse or promote products derived from
    this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.

***************************************************************************/

/* $FreeBSD: src/sys/dev/em/if_em.c,v 1.65.2.28 2007/11/07 01:33:28 jfv Exp $*/

#ifdef HAVE_KERNEL_OPTION_HEADERS
#include "opt_device_polling.h"
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/endian.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/rman.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/sysctl.h>
#include <sys/taskqueue.h>

#include <machine/bus.h>
#include <machine/resource.h>

#include <net/bpf.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <net/if_dl.h>
#include <net/if_media.h>

#include <net/if_types.h>
#include <net/if_vlan_var.h>

#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>

#include <machine/in_cksum.h>
#include <dev/pci/pcivar.h>
#include <dev/pci/pcireg.h>

#include "e1000_api.h"
#include "e1000_82575.h"
#include "if_em.h"

/*********************************************************************
 *  Set this to one to display debug statistics
 *********************************************************************/
int   em_display_debug_stats = 0;

/*********************************************************************
 *  Driver version:
 *********************************************************************/
char em_driver_version[] = "Version - 6.7.2";


/*********************************************************************
 *  PCI Device ID Table
 *
 *  Used by probe to select devices to load on
 *  Last field stores an index into e1000_strings
 *  Last entry must be all 0s
 *
 *  { Vendor ID, Device ID, SubVendor ID, SubDevice ID, String Index }
 *********************************************************************/

static em_vendor_info_t em_vendor_info_array[] =
{
      /* Intel(R) PRO/1000 Network Connection */
      { 0x8086, E1000_DEV_ID_82540EM,           PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82540EM_LOM, PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82540EP,           PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82540EP_LOM, PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82540EP_LP,  PCI_ANY_ID, PCI_ANY_ID, 0},

      { 0x8086, E1000_DEV_ID_82541EI,           PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82541ER,           PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82541ER_LOM, PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82541EI_MOBILE,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82541GI,           PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82541GI_LF,  PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82541GI_MOBILE,    PCI_ANY_ID, PCI_ANY_ID, 0},

      { 0x8086, E1000_DEV_ID_82542,       PCI_ANY_ID, PCI_ANY_ID, 0},

      { 0x8086, E1000_DEV_ID_82543GC_FIBER,     PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82543GC_COPPER,    PCI_ANY_ID, PCI_ANY_ID, 0},

      { 0x8086, E1000_DEV_ID_82544EI_COPPER,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82544EI_FIBER,     PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82544GC_COPPER,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82544GC_LOM, PCI_ANY_ID, PCI_ANY_ID, 0},

      { 0x8086, E1000_DEV_ID_82545EM_COPPER,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82545EM_FIBER,     PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82545GM_COPPER,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82545GM_FIBER,     PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82545GM_SERDES,    PCI_ANY_ID, PCI_ANY_ID, 0},

      { 0x8086, E1000_DEV_ID_82546EB_COPPER,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82546EB_FIBER,     PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82546EB_QUAD_COPPER, PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82546GB_COPPER,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82546GB_FIBER,     PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82546GB_SERDES,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82546GB_PCIE,      PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82546GB_QUAD_COPPER, PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82546GB_QUAD_COPPER_KSP3,
                                    PCI_ANY_ID, PCI_ANY_ID, 0},

      { 0x8086, E1000_DEV_ID_82547EI,           PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82547EI_MOBILE,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82547GI,           PCI_ANY_ID, PCI_ANY_ID, 0},

      { 0x8086, E1000_DEV_ID_82571EB_COPPER,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82571EB_FIBER,     PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82571EB_SERDES,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82571EB_QUAD_COPPER,
                                    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82571EB_QUAD_COPPER_LP,
                                    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82571EB_QUAD_FIBER,
                                    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82571PT_QUAD_COPPER,
                                    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82572EI_COPPER,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82572EI_FIBER,     PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82572EI_SERDES,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82572EI,           PCI_ANY_ID, PCI_ANY_ID, 0},

      { 0x8086, E1000_DEV_ID_82573E,            PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82573E_IAMT, PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82573L,            PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_80003ES2LAN_COPPER_SPT,
                                    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_80003ES2LAN_SERDES_SPT,
                                    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_80003ES2LAN_COPPER_DPT,
                                    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_80003ES2LAN_SERDES_DPT,
                                    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_ICH8_IGP_M_AMT,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_ICH8_IGP_AMT,      PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_ICH8_IGP_C,  PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_ICH8_IFE,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_ICH8_IFE_GT, PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_ICH8_IFE_G,  PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_ICH8_IGP_M,  PCI_ANY_ID, PCI_ANY_ID, 0},

      { 0x8086, E1000_DEV_ID_ICH9_IGP_AMT,      PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_ICH9_IGP_C,  PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_ICH9_IFE,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_ICH9_IFE_GT, PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_ICH9_IFE_G,  PCI_ANY_ID, PCI_ANY_ID, 0},

      { 0x8086, E1000_DEV_ID_82575EB_COPPER,    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82575EB_FIBER_SERDES,
                                    PCI_ANY_ID, PCI_ANY_ID, 0},
      { 0x8086, E1000_DEV_ID_82575GB_QUAD_COPPER,
                                    PCI_ANY_ID, PCI_ANY_ID, 0},
      /* required last entry */
      { 0, 0, 0, 0, 0}
};

/*********************************************************************
 *  Table of branding strings for all supported NICs.
 *********************************************************************/

static char *em_strings[] = {
      "Intel(R) PRO/1000 Network Connection"
};

/*********************************************************************
 *  Function prototypes
 *********************************************************************/
static int  em_probe(device_t);
static int  em_attach(device_t);
static int  em_detach(device_t);
static int  em_shutdown(device_t);
static int  em_suspend(device_t);
static int  em_resume(device_t);
static void em_start(struct ifnet *);
static void em_start_locked(struct ifnet *ifp);
static int  em_ioctl(struct ifnet *, u_long, caddr_t);
static void em_watchdog(struct adapter *);
static void em_init(void *);
static void em_init_locked(struct adapter *);
static void em_stop(void *);
static void em_media_status(struct ifnet *, struct ifmediareq *);
static int  em_media_change(struct ifnet *);
static void em_identify_hardware(struct adapter *);
static int  em_allocate_pci_resources(struct adapter *);
static int  em_allocate_intr(struct adapter *);
static bool em_setup_msix(struct adapter *);
static void em_free_intr(struct adapter *);
static void em_free_pci_resources(struct adapter *);
static void em_local_timer(void *);
static int  em_hardware_init(struct adapter *);
static void em_setup_interface(device_t, struct adapter *);
static void em_setup_transmit_structures(struct adapter *);
static void em_initialize_transmit_unit(struct adapter *);
static int  em_setup_receive_structures(struct adapter *);
static void em_initialize_receive_unit(struct adapter *);
static void em_enable_intr(struct adapter *);
static void em_disable_intr(struct adapter *);
static void em_free_transmit_structures(struct adapter *);
static void em_free_receive_structures(struct adapter *);
static void em_update_stats_counters(struct adapter *);
static void em_txeof(struct adapter *);
static void em_tx_purge(struct adapter *);
static int  em_allocate_receive_structures(struct adapter *);
static int  em_allocate_transmit_structures(struct adapter *);
static int  em_rxeof(struct adapter *, int);
#ifndef __NO_STRICT_ALIGNMENT
static int  em_fixup_rx(struct adapter *);
#endif
static void em_receive_checksum(struct adapter *, struct e1000_rx_desc *,
                struct mbuf *);
static void em_transmit_checksum_setup(struct adapter *, struct mbuf *,
                uint32_t *, uint32_t *);
static boolean_t em_tx_adv_ctx_setup(struct adapter *, struct mbuf *);
#if __FreeBSD_version >= 700000
static boolean_t em_tso_setup(struct adapter *, struct mbuf *, uint32_t *,
                uint32_t *);
static boolean_t em_tso_adv_setup(struct adapter *, struct mbuf *, uint32_t *);
#endif /* FreeBSD_version >= 700000 */
static void em_set_promisc(struct adapter *);
static void em_disable_promisc(struct adapter *);
static void em_set_multi(struct adapter *);
static void em_print_hw_stats(struct adapter *);
static void em_update_link_status(struct adapter *);
static int  em_get_buf(struct adapter *, int);
static void em_enable_hw_vlans(struct adapter *);
static int  em_encap(struct adapter *, struct mbuf **);
static int  em_adv_encap(struct adapter *, struct mbuf **);
static void em_smartspeed(struct adapter *);
static int  em_82547_fifo_workaround(struct adapter *, int);
static void em_82547_update_fifo_head(struct adapter *, int);
static int  em_82547_tx_fifo_reset(struct adapter *);
static void em_82547_move_tail(void *);
static int  em_dma_malloc(struct adapter *, bus_size_t,
                struct em_dma_alloc *, int);
static void em_dma_free(struct adapter *, struct em_dma_alloc *);
static void em_print_debug_info(struct adapter *);
static void em_print_nvm_info(struct adapter *);
static int  em_is_valid_ether_addr(uint8_t *);
static int  em_sysctl_stats(SYSCTL_HANDLER_ARGS);
static int  em_sysctl_debug_info(SYSCTL_HANDLER_ARGS);
static uint32_t   em_fill_descriptors (bus_addr_t address, uint32_t length,
                PDESC_ARRAY desc_array);
static int  em_sysctl_int_delay(SYSCTL_HANDLER_ARGS);
static void em_add_int_delay_sysctl(struct adapter *, const char *,
                const char *, struct em_int_delay_info *, int, int);
/* Management and WOL Support */
static void em_init_manageability(struct adapter *);
static void em_release_manageability(struct adapter *);
static void     em_get_hw_control(struct adapter *);
static void     em_release_hw_control(struct adapter *);
static void     em_enable_wakeup(device_t);

#ifndef EM_FAST_IRQ
static void em_intr(void *);
#ifdef DEVICE_POLLING
static poll_handler_t em_poll;
#endif /* POLLING */
#else /* FAST IRQ */
#if __FreeBSD_version < 700000
static void em_intr_fast(void *);
#else
static int  em_intr_fast(void *);
#endif
static void em_add_rx_process_limit(struct adapter *, const char *,
                const char *, int *, int);
static void em_handle_rxtx(void *context, int pending);
static void em_handle_link(void *context, int pending);
#endif /* EM_FAST_IRQ */

/*********************************************************************
 *  FreeBSD Device Interface Entry Points
 *********************************************************************/

static device_method_t em_methods[] = {
      /* Device interface */
      DEVMETHOD(device_probe, em_probe),
      DEVMETHOD(device_attach, em_attach),
      DEVMETHOD(device_detach, em_detach),
      DEVMETHOD(device_shutdown, em_shutdown),
      DEVMETHOD(device_suspend, em_suspend),
      DEVMETHOD(device_resume, em_resume),
      {0, 0}
};

static driver_t em_driver = {
      "em", em_methods, sizeof(struct adapter),
};

static devclass_t em_devclass;
DRIVER_MODULE(em, pci, em_driver, em_devclass, 0, 0);
MODULE_DEPEND(em, pci, 1, 1, 1);
MODULE_DEPEND(em, ether, 1, 1, 1);

/*********************************************************************
 *  Tunable default values.
 *********************************************************************/

#define EM_TICKS_TO_USECS(ticks)    ((1024 * (ticks) + 500) / 1000)
#define EM_USECS_TO_TICKS(usecs)    ((1000 * (usecs) + 512) / 1024)
#define M_TSO_LEN             66

/* Allow common code without TSO */
#ifndef CSUM_TSO
#define CSUM_TSO  0
#endif

static int em_tx_int_delay_dflt = EM_TICKS_TO_USECS(EM_TIDV);
static int em_rx_int_delay_dflt = EM_TICKS_TO_USECS(EM_RDTR);
static int em_tx_abs_int_delay_dflt = EM_TICKS_TO_USECS(EM_TADV);
static int em_rx_abs_int_delay_dflt = EM_TICKS_TO_USECS(EM_RADV);
static int em_rxd = EM_DEFAULT_RXD;
static int em_txd = EM_DEFAULT_TXD;
static int em_smart_pwr_down = FALSE;

TUNABLE_INT("hw.em.tx_int_delay", &em_tx_int_delay_dflt);
TUNABLE_INT("hw.em.rx_int_delay", &em_rx_int_delay_dflt);
TUNABLE_INT("hw.em.tx_abs_int_delay", &em_tx_abs_int_delay_dflt);
TUNABLE_INT("hw.em.rx_abs_int_delay", &em_rx_abs_int_delay_dflt);
TUNABLE_INT("hw.em.rxd", &em_rxd);
TUNABLE_INT("hw.em.txd", &em_txd);
TUNABLE_INT("hw.em.smart_pwr_down", &em_smart_pwr_down);
#ifdef EM_FAST_IRQ
/* How many packets rxeof tries to clean at a time */
static int em_rx_process_limit = 100;
TUNABLE_INT("hw.em.rx_process_limit", &em_rx_process_limit);
#endif
/* Global used in WOL setup with multiport cards */
static int global_quad_port_a = 0;

/*********************************************************************
 *  Device identification routine
 *
 *  em_probe determines if the driver should be loaded on
 *  adapter based on PCI vendor/device id of the adapter.
 *
 *  return BUS_PROBE_DEFAULT on success, positive on failure
 *********************************************************************/

static int
em_probe(device_t dev)
{
      char        adapter_name[60];
      uint16_t    pci_vendor_id = 0;
      uint16_t    pci_device_id = 0;
      uint16_t    pci_subvendor_id = 0;
      uint16_t    pci_subdevice_id = 0;
      em_vendor_info_t *ent;

      INIT_DEBUGOUT("em_probe: begin");

      pci_vendor_id = pci_get_vendor(dev);
      if (pci_vendor_id != EM_VENDOR_ID)
            return (ENXIO);

      pci_device_id = pci_get_device(dev);
      pci_subvendor_id = pci_get_subvendor(dev);
      pci_subdevice_id = pci_get_subdevice(dev);

      ent = em_vendor_info_array;
      while (ent->vendor_id != 0) {
            if ((pci_vendor_id == ent->vendor_id) &&
                (pci_device_id == ent->device_id) &&

                ((pci_subvendor_id == ent->subvendor_id) ||
                (ent->subvendor_id == PCI_ANY_ID)) &&

                ((pci_subdevice_id == ent->subdevice_id) ||
                (ent->subdevice_id == PCI_ANY_ID))) {
                  sprintf(adapter_name, "%s %s",
                        em_strings[ent->index],
                        em_driver_version);
                  device_set_desc_copy(dev, adapter_name);
                  return (BUS_PROBE_DEFAULT);
            }
            ent++;
      }

      return (ENXIO);
}

/*********************************************************************
 *  Device initialization routine
 *
 *  The attach entry point is called when the driver is being loaded.
 *  This routine identifies the type of hardware, allocates all resources
 *  and initializes the hardware.
 *
 *  return 0 on success, positive on failure
 *********************************************************************/

static int
em_attach(device_t dev)
{
      struct adapter    *adapter;
      int         tsize, rsize;
      int         error = 0;
      u16         eeprom_data, device_id;

      INIT_DEBUGOUT("em_attach: begin");

      adapter = device_get_softc(dev);
      adapter->dev = adapter->osdep.dev = dev;
      EM_CORE_LOCK_INIT(adapter, device_get_nameunit(dev));
      EM_TX_LOCK_INIT(adapter, device_get_nameunit(dev));

      /* SYSCTL stuff */
      SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
          SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
          OID_AUTO, "debug", CTLTYPE_INT|CTLFLAG_RW, adapter, 0,
          em_sysctl_debug_info, "I", "Debug Information");

      SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
          SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
          OID_AUTO, "stats", CTLTYPE_INT|CTLFLAG_RW, adapter, 0,
          em_sysctl_stats, "I", "Statistics");

      callout_init_mtx(&adapter->timer, &adapter->core_mtx, 0);
      callout_init_mtx(&adapter->tx_fifo_timer, &adapter->tx_mtx, 0);

      /* Determine hardware and mac info */
      em_identify_hardware(adapter);

      /* Setup PCI resources */
      if (em_allocate_pci_resources(adapter)) {
            device_printf(dev, "Allocation of PCI resources failed\n");
            error = ENXIO;
            goto err_pci;
      }

      /*
      ** For ICH8 and family we need to
      ** map the flash memory, and this
      ** must happen after the MAC is 
      ** identified
      */
      if ((adapter->hw.mac.type == e1000_ich8lan) ||
          (adapter->hw.mac.type == e1000_ich9lan)) {
            int rid = EM_BAR_TYPE_FLASH;
            adapter->flash_mem = bus_alloc_resource_any(dev,
                SYS_RES_MEMORY, &rid, RF_ACTIVE);
            /* This is used in the shared code */
            adapter->hw.flash_address = (u8 *)adapter->flash_mem;
            adapter->osdep.flash_bus_space_tag =
                rman_get_bustag(adapter->flash_mem);
            adapter->osdep.flash_bus_space_handle =
                rman_get_bushandle(adapter->flash_mem);
      }

      /* Do Shared Code initialization */
      if (e1000_setup_init_funcs(&adapter->hw, TRUE)) {
            device_printf(dev, "Setup of Shared code failed\n");
            error = ENXIO;
            goto err_pci;
      }

      e1000_get_bus_info(&adapter->hw);

      /* Set up some sysctls for the tunable interrupt delays */
      em_add_int_delay_sysctl(adapter, "rx_int_delay",
          "receive interrupt delay in usecs", &adapter->rx_int_delay,
          E1000_REGISTER(&adapter->hw, E1000_RDTR), em_rx_int_delay_dflt);
      em_add_int_delay_sysctl(adapter, "tx_int_delay",
          "transmit interrupt delay in usecs", &adapter->tx_int_delay,
          E1000_REGISTER(&adapter->hw, E1000_TIDV), em_tx_int_delay_dflt);
      if (adapter->hw.mac.type >= e1000_82540) {
            em_add_int_delay_sysctl(adapter, "rx_abs_int_delay",
                "receive interrupt delay limit in usecs",
                &adapter->rx_abs_int_delay,
                E1000_REGISTER(&adapter->hw, E1000_RADV),
                em_rx_abs_int_delay_dflt);
            em_add_int_delay_sysctl(adapter, "tx_abs_int_delay",
                "transmit interrupt delay limit in usecs",
                &adapter->tx_abs_int_delay,
                E1000_REGISTER(&adapter->hw, E1000_TADV),
                em_tx_abs_int_delay_dflt);
      }

#ifdef EM_FAST_IRQ
      /* Sysctls for limiting the amount of work done in the taskqueue */
      em_add_rx_process_limit(adapter, "rx_processing_limit",
          "max number of rx packets to process", &adapter->rx_process_limit,
          em_rx_process_limit);
#endif

      /*
       * Validate number of transmit and receive descriptors. It
       * must not exceed hardware maximum, and must be multiple
       * of E1000_DBA_ALIGN.
       */
      if (((em_txd * sizeof(struct e1000_tx_desc)) % EM_DBA_ALIGN) != 0 ||
          (adapter->hw.mac.type >= e1000_82544 && em_txd > EM_MAX_TXD) ||
          (adapter->hw.mac.type < e1000_82544 && em_txd > EM_MAX_TXD_82543) ||
          (em_txd < EM_MIN_TXD)) {
            device_printf(dev, "Using %d TX descriptors instead of %d!\n",
                EM_DEFAULT_TXD, em_txd);
            adapter->num_tx_desc = EM_DEFAULT_TXD;
      } else
            adapter->num_tx_desc = em_txd;
      if (((em_rxd * sizeof(struct e1000_rx_desc)) % EM_DBA_ALIGN) != 0 ||
          (adapter->hw.mac.type >= e1000_82544 && em_rxd > EM_MAX_RXD) ||
          (adapter->hw.mac.type < e1000_82544 && em_rxd > EM_MAX_RXD_82543) ||
          (em_rxd < EM_MIN_RXD)) {
            device_printf(dev, "Using %d RX descriptors instead of %d!\n",
                EM_DEFAULT_RXD, em_rxd);
            adapter->num_rx_desc = EM_DEFAULT_RXD;
      } else
            adapter->num_rx_desc = em_rxd;

      adapter->hw.mac.autoneg = DO_AUTO_NEG;
      adapter->hw.phy.autoneg_wait_to_complete = FALSE;
      adapter->hw.phy.autoneg_advertised = AUTONEG_ADV_DEFAULT;
      adapter->rx_buffer_len = 2048;

      e1000_init_script_state_82541(&adapter->hw, TRUE);
      e1000_set_tbi_compatibility_82543(&adapter->hw, TRUE);

      /* Copper options */
      if (adapter->hw.phy.media_type == e1000_media_type_copper) {
            adapter->hw.phy.mdix = AUTO_ALL_MODES;
            adapter->hw.phy.disable_polarity_correction = FALSE;
            adapter->hw.phy.ms_type = EM_MASTER_SLAVE;
      }

      /*
       * Set the frame limits assuming
       * standard ethernet sized frames.
       */
      adapter->max_frame_size = ETHERMTU + ETHER_HDR_LEN + ETHERNET_FCS_SIZE;
      adapter->min_frame_size = ETH_ZLEN + ETHERNET_FCS_SIZE;

      /*
       * This controls when hardware reports transmit completion
       * status.
       */
      adapter->hw.mac.report_tx_early = 1;

      tsize = roundup2(adapter->num_tx_desc * sizeof(struct e1000_tx_desc),
          EM_DBA_ALIGN);

      /* Allocate Transmit Descriptor ring */
      if (em_dma_malloc(adapter, tsize, &adapter->txdma, BUS_DMA_NOWAIT)) {
            device_printf(dev, "Unable to allocate tx_desc memory\n");
            error = ENOMEM;
            goto err_tx_desc;
      }
      adapter->tx_desc_base = 
          (struct e1000_tx_desc *)adapter->txdma.dma_vaddr;

      rsize = roundup2(adapter->num_rx_desc * sizeof(struct e1000_rx_desc),
          EM_DBA_ALIGN);

      /* Allocate Receive Descriptor ring */
      if (em_dma_malloc(adapter, rsize, &adapter->rxdma, BUS_DMA_NOWAIT)) {
            device_printf(dev, "Unable to allocate rx_desc memory\n");
            error = ENOMEM;
            goto err_rx_desc;
      }
      adapter->rx_desc_base =
          (struct e1000_rx_desc *)adapter->rxdma.dma_vaddr;

      /* Make sure we have a good EEPROM before we read from it */
      if (e1000_validate_nvm_checksum(&adapter->hw) < 0) {
            /*
            ** Some PCI-E parts fail the first check due to
            ** the link being in sleep state, call it again,
            ** if it fails a second time its a real issue.
            */
            if (e1000_validate_nvm_checksum(&adapter->hw) < 0) {
                  device_printf(dev,
                      "The EEPROM Checksum Is Not Valid\n");
                  error = EIO;
                  goto err_hw_init;
            }
      }

      /* Initialize the hardware */
      if (em_hardware_init(adapter)) {
            device_printf(dev, "Unable to initialize the hardware\n");
            error = EIO;
            goto err_hw_init;
      }

      /* Copy the permanent MAC address out of the EEPROM */
      if (e1000_read_mac_addr(&adapter->hw) < 0) {
            device_printf(dev, "EEPROM read error while reading MAC"
                " address\n");
            error = EIO;
            goto err_hw_init;
      }

      if (!em_is_valid_ether_addr(adapter->hw.mac.addr)) {
            device_printf(dev, "Invalid MAC address\n");
            error = EIO;
            goto err_hw_init;
      }

      /* Allocate transmit descriptors and buffers */
      if (em_allocate_transmit_structures(adapter)) {
            device_printf(dev, "Could not setup transmit structures\n");
            error = ENOMEM;
            goto err_tx_struct;
      }

      /* Allocate receive descriptors and buffers */
      if (em_allocate_receive_structures(adapter)) {
            device_printf(dev, "Could not setup receive structures\n");
            error = ENOMEM;
            goto err_rx_struct;
      }

      /* Setup OS specific network interface */
      em_setup_interface(dev, adapter);

      em_allocate_intr(adapter);

      /* Initialize statistics */
      em_update_stats_counters(adapter);

      adapter->hw.mac.get_link_status = 1;
      em_update_link_status(adapter);

      /* Indicate SOL/IDER usage */
      if (e1000_check_reset_block(&adapter->hw))
            device_printf(dev,
                "PHY reset is blocked due to SOL/IDER session.\n");

      /* Determine if we have to control management hardware */
      adapter->has_manage = e1000_enable_mng_pass_thru(&adapter->hw);

      /*
       * Setup Wake-on-Lan
       */
      switch (adapter->hw.mac.type) {

      case e1000_82542:
      case e1000_82543:
            break;
      case e1000_82546:
      case e1000_82546_rev_3:
      case e1000_82571:
      case e1000_80003es2lan:
            if (adapter->hw.bus.func == 1)
                  e1000_read_nvm(&adapter->hw,
                      NVM_INIT_CONTROL3_PORT_B, 1, &eeprom_data);
            else
                  e1000_read_nvm(&adapter->hw,
                      NVM_INIT_CONTROL3_PORT_A, 1, &eeprom_data);
            eeprom_data &= EM_EEPROM_APME;
            break;
      default:
            /* APME bit in EEPROM is mapped to WUC.APME */
            eeprom_data = E1000_READ_REG(&adapter->hw, E1000_WUC) &
                E1000_WUC_APME;
            break;
      }
      if (eeprom_data)
            adapter->wol = E1000_WUFC_MAG;
      /*
         * We have the eeprom settings, now apply the special cases
         * where the eeprom may be wrong or the board won't support
         * wake on lan on a particular port
       */
      device_id = pci_get_device(dev);
        switch (device_id) {
      case E1000_DEV_ID_82546GB_PCIE:
            adapter->wol = 0;
            break;
      case E1000_DEV_ID_82546EB_FIBER:
      case E1000_DEV_ID_82546GB_FIBER:
      case E1000_DEV_ID_82571EB_FIBER:
            /* Wake events only supported on port A for dual fiber
             * regardless of eeprom setting */
            if (E1000_READ_REG(&adapter->hw, E1000_STATUS) &
                E1000_STATUS_FUNC_1)
                  adapter->wol = 0;
            break;
      case E1000_DEV_ID_82546GB_QUAD_COPPER_KSP3:
      case E1000_DEV_ID_82571EB_QUAD_COPPER:
      case E1000_DEV_ID_82571EB_QUAD_FIBER:
      case E1000_DEV_ID_82571EB_QUAD_COPPER_LP:
                /* if quad port adapter, disable WoL on all but port A */
            if (global_quad_port_a != 0)
                  adapter->wol = 0;
            /* Reset for multiple quad port adapters */
            if (++global_quad_port_a == 4)
                  global_quad_port_a = 0;
                break;
      }

      /* Do we need workaround for 82544 PCI-X adapter? */
      if (adapter->hw.bus.type == e1000_bus_type_pcix &&
          adapter->hw.mac.type == e1000_82544)
            adapter->pcix_82544 = TRUE;
      else
            adapter->pcix_82544 = FALSE;

      /* Tell the stack that the interface is not active */
      adapter->ifp->if_drv_flags &= ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);

      INIT_DEBUGOUT("em_attach: end");

      return (0);

err_rx_struct:
      em_free_transmit_structures(adapter);
err_tx_struct:
err_hw_init:
      em_release_hw_control(adapter);
      e1000_remove_device(&adapter->hw);
      em_dma_free(adapter, &adapter->rxdma);
err_rx_desc:
      em_dma_free(adapter, &adapter->txdma);
err_tx_desc:
err_pci:
      em_free_intr(adapter);
      em_free_pci_resources(adapter);
      EM_TX_LOCK_DESTROY(adapter);
      EM_CORE_LOCK_DESTROY(adapter);

      return (error);
}

/*********************************************************************
 *  Device removal routine
 *
 *  The detach entry point is called when the driver is being removed.
 *  This routine stops the adapter and deallocates all the resources
 *  that were allocated for driver operation.
 *
 *  return 0 on success, positive on failure
 *********************************************************************/

static int
em_detach(device_t dev)
{
      struct adapter    *adapter = device_get_softc(dev);
      struct ifnet      *ifp = adapter->ifp;

      INIT_DEBUGOUT("em_detach: begin");

      /* Make sure VLANS are not using driver */
#if __FreeBSD_version >= 700000
      if (adapter->ifp->if_vlantrunk != NULL) {
#else
      if (adapter->ifp->if_nvlans != 0) {
#endif   
            device_printf(dev,"Vlan in use, detach first\n");
            return (EBUSY);
      }

#ifdef DEVICE_POLLING
      if (ifp->if_capenable & IFCAP_POLLING)
            ether_poll_deregister(ifp);
#endif

      em_disable_intr(adapter);
      em_free_intr(adapter);
      EM_CORE_LOCK(adapter);
      adapter->in_detach = 1;
      em_stop(adapter);
      e1000_phy_hw_reset(&adapter->hw);

      em_release_manageability(adapter);

      if (((adapter->hw.mac.type == e1000_82573) ||
          (adapter->hw.mac.type == e1000_ich8lan) ||
          (adapter->hw.mac.type == e1000_ich9lan)) &&
          e1000_check_mng_mode(&adapter->hw))
            em_release_hw_control(adapter);

      if (adapter->wol) {
            E1000_WRITE_REG(&adapter->hw, E1000_WUC, E1000_WUC_PME_EN);
            E1000_WRITE_REG(&adapter->hw, E1000_WUFC, adapter->wol);
            em_enable_wakeup(dev);
      }

      EM_CORE_UNLOCK(adapter);
      ether_ifdetach(adapter->ifp);

      callout_drain(&adapter->timer);
      callout_drain(&adapter->tx_fifo_timer);

      em_free_pci_resources(adapter);
      bus_generic_detach(dev);
      if_free(ifp);

      e1000_remove_device(&adapter->hw);
      em_free_transmit_structures(adapter);
      em_free_receive_structures(adapter);

      /* Free Transmit Descriptor ring */
      if (adapter->tx_desc_base) {
            em_dma_free(adapter, &adapter->txdma);
            adapter->tx_desc_base = NULL;
      }

      /* Free Receive Descriptor ring */
      if (adapter->rx_desc_base) {
            em_dma_free(adapter, &adapter->rxdma);
            adapter->rx_desc_base = NULL;
      }

      EM_TX_LOCK_DESTROY(adapter);
      EM_CORE_LOCK_DESTROY(adapter);

      return (0);
}

/*********************************************************************
 *
 *  Shutdown entry point
 *
 **********************************************************************/

static int
em_shutdown(device_t dev)
{
      return em_suspend(dev);
}

/*
 * Suspend/resume device methods.
 */
static int
em_suspend(device_t dev)
{
      struct adapter *adapter = device_get_softc(dev);

      EM_CORE_LOCK(adapter);
      em_stop(adapter);

        em_release_manageability(adapter);

        if (((adapter->hw.mac.type == e1000_82573) ||
            (adapter->hw.mac.type == e1000_ich8lan) ||
            (adapter->hw.mac.type == e1000_ich9lan)) &&
            e1000_check_mng_mode(&adapter->hw))
                em_release_hw_control(adapter);

        if (adapter->wol) {
                E1000_WRITE_REG(&adapter->hw, E1000_WUC, E1000_WUC_PME_EN);
                E1000_WRITE_REG(&adapter->hw, E1000_WUFC, adapter->wol);
                em_enable_wakeup(dev);
        }

      EM_CORE_UNLOCK(adapter);

      return bus_generic_suspend(dev);
}

static int
em_resume(device_t dev)
{
      struct adapter *adapter = device_get_softc(dev);
      struct ifnet *ifp = adapter->ifp;

      EM_CORE_LOCK(adapter);
      em_init_locked(adapter);
      em_init_manageability(adapter);

      if ((ifp->if_flags & IFF_UP) &&
          (ifp->if_drv_flags & IFF_DRV_RUNNING))
            em_start_locked(ifp);

      EM_CORE_UNLOCK(adapter);

      return bus_generic_resume(dev);
}


/*********************************************************************
 *  Transmit entry point
 *
 *  em_start is called by the stack to initiate a transmit.
 *  The driver will remain in this routine as long as there are
 *  packets to transmit and transmit resources are available.
 *  In case resources are not available stack is notified and
 *  the packet is requeued.
 **********************************************************************/

static void
em_start_locked(struct ifnet *ifp)
{
      struct adapter    *adapter = ifp->if_softc;
      struct mbuf *m_head;

      EM_TX_LOCK_ASSERT(adapter);

      if ((ifp->if_drv_flags & (IFF_DRV_RUNNING|IFF_DRV_OACTIVE)) !=
          IFF_DRV_RUNNING)
            return;
      if (!adapter->link_active)
            return;

      while (!IFQ_DRV_IS_EMPTY(&ifp->if_snd)) {

            IFQ_DRV_DEQUEUE(&ifp->if_snd, m_head);
            if (m_head == NULL)
                  break;
            /*
             *  Encapsulation can modify our pointer, and or make it
             *  NULL on failure.  In that event, we can't requeue.
             *
             *  We now use a pointer to accomodate legacy and
             *  advanced transmit functions.
             */
            if (adapter->em_xmit(adapter, &m_head)) {
                  if (m_head == NULL)
                        break;
                  ifp->if_drv_flags |= IFF_DRV_OACTIVE;
                  IFQ_DRV_PREPEND(&ifp->if_snd, m_head);
                  break;
            }

            /* Send a copy of the frame to the BPF listener */
            ETHER_BPF_MTAP(ifp, m_head);

            /* Set timeout in case hardware has problems transmitting. */
            adapter->watchdog_timer = EM_TX_TIMEOUT;
      }
}

static void
em_start(struct ifnet *ifp)
{
      struct adapter *adapter = ifp->if_softc;

      EM_TX_LOCK(adapter);
      if (ifp->if_drv_flags & IFF_DRV_RUNNING)
            em_start_locked(ifp);
      EM_TX_UNLOCK(adapter);
}

/*********************************************************************
 *  Ioctl entry point
 *
 *  em_ioctl is called when the user wants to configure the
 *  interface.
 *
 *  return 0 on success, positive on failure
 **********************************************************************/

static int
em_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
{
      struct adapter    *adapter = ifp->if_softc;
      struct ifreq *ifr = (struct ifreq *)data;
      struct ifaddr *ifa = (struct ifaddr *)data;
      int error = 0;

      if (adapter->in_detach)
            return (error);

      switch (command) {
      case SIOCSIFADDR:
            if (ifa->ifa_addr->sa_family == AF_INET) {
                  /*
                   * XXX
                   * Since resetting hardware takes a very long time
                   * and results in link renegotiation we only
                   * initialize the hardware only when it is absolutely
                   * required.
                   */
                  ifp->if_flags |= IFF_UP;
                  if (!(ifp->if_drv_flags & IFF_DRV_RUNNING)) {
                        EM_CORE_LOCK(adapter);
                        em_init_locked(adapter);
                        EM_CORE_UNLOCK(adapter);
                  }
                  arp_ifinit(ifp, ifa);
            } else
                  error = ether_ioctl(ifp, command, data);
            break;
      case SIOCSIFMTU:
          {
            int max_frame_size;
            uint16_t eeprom_data = 0;

            IOCTL_DEBUGOUT("ioctl rcv'd: SIOCSIFMTU (Set Interface MTU)");

            EM_CORE_LOCK(adapter);
            switch (adapter->hw.mac.type) {
            case e1000_82573:
                  /*
                   * 82573 only supports jumbo frames
                   * if ASPM is disabled.
                   */
                  e1000_read_nvm(&adapter->hw,
                      NVM_INIT_3GIO_3, 1, &eeprom_data);
                  if (eeprom_data & NVM_WORD1A_ASPM_MASK) {
                        max_frame_size = ETHER_MAX_LEN;
                        break;
                  }
                  /* Allow Jumbo frames - fall thru */
            case e1000_82571:
            case e1000_82572:
            case e1000_ich9lan:
            case e1000_82575:
            case e1000_80003es2lan: /* Limit Jumbo Frame size */
                  max_frame_size = 9234;
                  break;
                  /* Adapters that do not support jumbo frames */
            case e1000_82542:
            case e1000_ich8lan:
                  max_frame_size = ETHER_MAX_LEN;
                  break;
            default:
                  max_frame_size = MAX_JUMBO_FRAME_SIZE;
            }
            if (ifr->ifr_mtu > max_frame_size - ETHER_HDR_LEN -
                ETHER_CRC_LEN) {
                  EM_CORE_UNLOCK(adapter);
                  error = EINVAL;
                  break;
            }

            ifp->if_mtu = ifr->ifr_mtu;
            adapter->max_frame_size =
                ifp->if_mtu + ETHER_HDR_LEN + ETHER_CRC_LEN;
            em_init_locked(adapter);
            EM_CORE_UNLOCK(adapter);
            break;
          }
      case SIOCSIFFLAGS:
            IOCTL_DEBUGOUT("ioctl rcv'd:\
                SIOCSIFFLAGS (Set Interface Flags)");
            EM_CORE_LOCK(adapter);
            if (ifp->if_flags & IFF_UP) {
                  if ((ifp->if_drv_flags & IFF_DRV_RUNNING)) {
                        if ((ifp->if_flags ^ adapter->if_flags) &
                            IFF_PROMISC) {
                              em_disable_promisc(adapter);
                              em_set_promisc(adapter);
                        }
                  } else
                        em_init_locked(adapter);
            } else
                  if (ifp->if_drv_flags & IFF_DRV_RUNNING)
                        em_stop(adapter);
            adapter->if_flags = ifp->if_flags;
            EM_CORE_UNLOCK(adapter);
            break;
      case SIOCADDMULTI:
      case SIOCDELMULTI:
            IOCTL_DEBUGOUT("ioctl rcv'd: SIOC(ADD|DEL)MULTI");
            if (ifp->if_drv_flags & IFF_DRV_RUNNING) {
                  EM_CORE_LOCK(adapter);
                  em_disable_intr(adapter);
                  em_set_multi(adapter);
                  if (adapter->hw.mac.type == e1000_82542 && 
                      adapter->hw.revision_id == E1000_REVISION_2) {
                        em_initialize_receive_unit(adapter);
                  }
#ifdef DEVICE_POLLING
                  if (!(ifp->if_capenable & IFCAP_POLLING))
#endif
                        em_enable_intr(adapter);
                  EM_CORE_UNLOCK(adapter);
            }
            break;
      case SIOCSIFMEDIA:
            /* Check SOL/IDER usage */
            EM_CORE_LOCK(adapter);
            if (e1000_check_reset_block(&adapter->hw)) {
                  EM_CORE_UNLOCK(adapter);
                  device_printf(adapter->dev, "Media change is"
                      " blocked due to SOL/IDER session.\n");
                  break;
            }
            EM_CORE_UNLOCK(adapter);
      case SIOCGIFMEDIA:
            IOCTL_DEBUGOUT("ioctl rcv'd: \
                SIOCxIFMEDIA (Get/Set Interface Media)");
            error = ifmedia_ioctl(ifp, ifr, &adapter->media, command);
            break;
      case SIOCSIFCAP:
          {
            int mask, reinit;

            IOCTL_DEBUGOUT("ioctl rcv'd: SIOCSIFCAP (Set Capabilities)");
            reinit = 0;
            mask = ifr->ifr_reqcap ^ ifp->if_capenable;
#ifdef DEVICE_POLLING
            if (mask & IFCAP_POLLING) {
                  if (ifr->ifr_reqcap & IFCAP_POLLING) {
                        error = ether_poll_register(em_poll, ifp);
                        if (error)
                              return (error);
                        EM_CORE_LOCK(adapter);
                        em_disable_intr(adapter);
                        ifp->if_capenable |= IFCAP_POLLING;
                        EM_CORE_UNLOCK(adapter);
                  } else {
                        error = ether_poll_deregister(ifp);
                        /* Enable interrupt even in error case */
                        EM_CORE_LOCK(adapter);
                        em_enable_intr(adapter);
                        ifp->if_capenable &= ~IFCAP_POLLING;
                        EM_CORE_UNLOCK(adapter);
                  }
            }
#endif
            if (mask & IFCAP_HWCSUM) {
                  ifp->if_capenable ^= IFCAP_HWCSUM;
                  reinit = 1;
            }
#if __FreeBSD_version >= 700000
            if (mask & IFCAP_TSO4) {
                  ifp->if_capenable ^= IFCAP_TSO4;
                  reinit = 1;
            }
#endif
            if (mask & IFCAP_VLAN_HWTAGGING) {
                  ifp->if_capenable ^= IFCAP_VLAN_HWTAGGING;
                  reinit = 1;
            }
            if (reinit && (ifp->if_drv_flags & IFF_DRV_RUNNING))
                  em_init(adapter);
#if __FreeBSD_version >= 700000
            VLAN_CAPABILITIES(ifp);
#endif
            break;
          }
      default:
            error = ether_ioctl(ifp, command, data);
            break;
      }

      return (error);
}

/*********************************************************************
 *  Watchdog timer:
 *
 *  This routine is called from the local timer every second.
 *  As long as transmit descriptors are being cleaned the value
 *  is non-zero and we do nothing. Reaching 0 indicates a tx hang
 *  and we then reset the device.
 *
 **********************************************************************/

static void
em_watchdog(struct adapter *adapter)
{
#ifdef EM_FAST_IRQ
      struct task *t = &adapter->rxtx_task;
#endif

      EM_CORE_LOCK_ASSERT(adapter);

      /*
      ** The timer is set to 10 every time start queues a packet.
      ** Then txeof keeps resetting to 10 as long as it cleans at
      ** least one descriptor.
      ** Finally, anytime all descriptors are clean the timer is
      ** set to 0.
      */
#ifndef EM_FAST_IRQ
      if ((adapter->watchdog_timer == 0) || (--adapter->watchdog_timer))
#else /* FAST_IRQ */
      if (adapter->watchdog_timer == 0)
#endif
            return;

#ifdef EM_FAST_IRQ
      /*
       * Force a clean if things seem sluggish, this
       * is a 6.3 scheduler workaround.
       */
      if ((--adapter->watchdog_timer != 0) && (t->ta_pending == 0)) {
            taskqueue_enqueue(adapter->tq, &adapter->rxtx_task);
            return;
      }
#endif

      /* If we are in this routine because of pause frames, then
       * don't reset the hardware.
       */
      if (E1000_READ_REG(&adapter->hw, E1000_STATUS) &
          E1000_STATUS_TXOFF) {
            adapter->watchdog_timer = EM_TX_TIMEOUT;
            return;
      }

      if (e1000_check_for_link(&adapter->hw) == 0)
            device_printf(adapter->dev, "watchdog timeout -- resetting\n");
      adapter->ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
      adapter->watchdog_events++;

      em_init_locked(adapter);
}

/*********************************************************************
 *  Init entry point
 *
 *  This routine is used in two ways. It is used by the stack as
 *  init entry point in network interface structure. It is also used
 *  by the driver as a hw/sw initialization routine to get to a
 *  consistent state.
 *
 *  return 0 on success, positive on failure
 **********************************************************************/

static void
em_init_locked(struct adapter *adapter)
{
      struct ifnet      *ifp = adapter->ifp;
      device_t    dev = adapter->dev;
      uint32_t    pba;

      INIT_DEBUGOUT("em_init: begin");

      EM_CORE_LOCK_ASSERT(adapter);

      em_stop(adapter);

      /*
       * Packet Buffer Allocation (PBA)
       * Writing PBA sets the receive portion of the buffer
       * the remainder is used for the transmit buffer.
       *
       * Devices before the 82547 had a Packet Buffer of 64K.
       *   Default allocation: PBA=48K for Rx, leaving 16K for Tx.
       * After the 82547 the buffer was reduced to 40K.
       *   Default allocation: PBA=30K for Rx, leaving 10K for Tx.
       *   Note: default does not leave enough room for Jumbo Frame >10k.
       */
      switch (adapter->hw.mac.type) {
      case e1000_82547:
      case e1000_82547_rev_2: /* 82547: Total Packet Buffer is 40K */
            if (adapter->max_frame_size > 8192)
                  pba = E1000_PBA_22K; /* 22K for Rx, 18K for Tx */
            else
                  pba = E1000_PBA_30K; /* 30K for Rx, 10K for Tx */
            adapter->tx_fifo_head = 0;
            adapter->tx_head_addr = pba << EM_TX_HEAD_ADDR_SHIFT;
            adapter->tx_fifo_size =
                (E1000_PBA_40K - pba) << EM_PBA_BYTES_SHIFT;
            break;
      /* Total Packet Buffer on these is 48K */
      case e1000_82571:
      case e1000_82572:
      case e1000_82575:
      case e1000_80003es2lan:
                  pba = E1000_PBA_32K; /* 32K for Rx, 16K for Tx */
            break;
      case e1000_82573: /* 82573: Total Packet Buffer is 32K */
                  pba = E1000_PBA_12K; /* 12K for Rx, 20K for Tx */
            break;
      case e1000_ich9lan:
#define E1000_PBA_10K   0x000A
            pba = E1000_PBA_10K;
            break;
      case e1000_ich8lan:
            pba = E1000_PBA_8K;
            break;
      default:
            /* Devices before 82547 had a Packet Buffer of 64K.   */
            if (adapter->max_frame_size > 8192)
                  pba = E1000_PBA_40K; /* 40K for Rx, 24K for Tx */
            else
                  pba = E1000_PBA_48K; /* 48K for Rx, 16K for Tx */
      }

      INIT_DEBUGOUT1("em_init: pba=%dK",pba);
      E1000_WRITE_REG(&adapter->hw, E1000_PBA, pba);
      
      /* Get the latest mac address, User can use a LAA */
        bcopy(IF_LLADDR(adapter->ifp), adapter->hw.mac.addr,
              ETHER_ADDR_LEN);

      /* Put the address into the Receive Address Array */
      e1000_rar_set(&adapter->hw, adapter->hw.mac.addr, 0);

      /*
       * With the 82571 adapter, RAR[0] may be overwritten
       * when the other port is reset, we make a duplicate
       * in RAR[14] for that eventuality, this assures
       * the interface continues to function.
       */
      if (adapter->hw.mac.type == e1000_82571) {
            e1000_set_laa_state_82571(&adapter->hw, TRUE);
            e1000_rar_set(&adapter->hw, adapter->hw.mac.addr,
                E1000_RAR_ENTRIES - 1);
      }

      /* Initialize the hardware */
      if (em_hardware_init(adapter)) {
            device_printf(dev, "Unable to initialize the hardware\n");
            return;
      }
      em_update_link_status(adapter);

      /* Setup VLAN support, basic and offload if available */
      E1000_WRITE_REG(&adapter->hw, E1000_VET, ETHERTYPE_VLAN);
      if (ifp->if_capenable & IFCAP_VLAN_HWTAGGING)
            em_enable_hw_vlans(adapter);

      /* Set hardware offload abilities */
      ifp->if_hwassist = 0;
      if (adapter->hw.mac.type >= e1000_82543) {
            if (ifp->if_capenable & IFCAP_TXCSUM)
                  ifp->if_hwassist |= (CSUM_TCP | CSUM_UDP);
#if __FreeBSD_version >= 700000
            if (ifp->if_capenable & IFCAP_TSO4)
                  ifp->if_hwassist |= CSUM_TSO;
#endif
      }

      /* Configure for OS presence */
      em_init_manageability(adapter);

      /* Prepare transmit descriptors and buffers */
      em_setup_transmit_structures(adapter);
      em_initialize_transmit_unit(adapter);

      /* Setup Multicast table */
      em_set_multi(adapter);

      /* Prepare receive descriptors and buffers */
      if (em_setup_receive_structures(adapter)) {
            device_printf(dev, "Could not setup receive structures\n");
            em_stop(adapter);
            return;
      }
      em_initialize_receive_unit(adapter);

      /* Don't lose promiscuous settings */
      em_set_promisc(adapter);

      ifp->if_drv_flags |= IFF_DRV_RUNNING;
      ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;

      callout_reset(&adapter->timer, hz, em_local_timer, adapter);
      e1000_clear_hw_cntrs_base_generic(&adapter->hw);

#ifdef DEVICE_POLLING
      /*
       * Only enable interrupts if we are not polling, make sure
       * they are off otherwise.
       */
      if (ifp->if_capenable & IFCAP_POLLING)
            em_disable_intr(adapter);
      else
#endif /* DEVICE_POLLING */
            em_enable_intr(adapter);

      /* Don't reset the phy next time init gets called */
      adapter->hw.phy.reset_disable = TRUE;
}

static void
em_init(void *arg)
{
      struct adapter *adapter = arg;

      EM_CORE_LOCK(adapter);
      em_init_locked(adapter);
      EM_CORE_UNLOCK(adapter);
}


#ifdef DEVICE_POLLING
/*********************************************************************
 *
 *  Legacy polling routine  
 *
 *********************************************************************/
static void
em_poll(struct ifnet *ifp, enum poll_cmd cmd, int count)
{
      struct adapter *adapter = ifp->if_softc;
      uint32_t reg_icr;

      EM_CORE_LOCK(adapter);
      if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0) {
            EM_CORE_UNLOCK(adapter);
            return;
      }

      if (cmd == POLL_AND_CHECK_STATUS) {
            reg_icr = E1000_READ_REG(&adapter->hw, E1000_ICR);
            if (reg_icr & (E1000_ICR_RXSEQ | E1000_ICR_LSC)) {
                  callout_stop(&adapter->timer);
                  adapter->hw.mac.get_link_status = 1;
                  e1000_check_for_link(&adapter->hw);
                  em_update_link_status(adapter);
                  callout_reset(&adapter->timer, hz,
                      em_local_timer, adapter);
            }
      }
      em_rxeof(adapter, count);
      EM_CORE_UNLOCK(adapter);

      EM_TX_LOCK(adapter);
      em_txeof(adapter);

      if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd))
            em_start_locked(ifp);
      EM_TX_UNLOCK(adapter);
}
#endif /* DEVICE_POLLING */

#ifndef EM_FAST_IRQ 
/*********************************************************************
 *
 *  Legacy Interrupt Service routine  
 *
 *********************************************************************/

static void
em_intr(void *arg)
{
      struct adapter    *adapter = arg;
      struct ifnet      *ifp;
      uint32_t    reg_icr;

      EM_CORE_LOCK(adapter);
      ifp = adapter->ifp;

      if (ifp->if_capenable & IFCAP_POLLING) {
            EM_CORE_UNLOCK(adapter);
            return;
      }

      for (;;) {
            reg_icr = E1000_READ_REG(&adapter->hw, E1000_ICR);

            if (adapter->hw.mac.type >= e1000_82571 &&
                (reg_icr & E1000_ICR_INT_ASSERTED) == 0)
                  break;
            else if (reg_icr == 0)
                  break;

            /*
             * XXX: some laptops trigger several spurious interrupts
             * on em(4) when in the resume cycle. The ICR register
             * reports all-ones value in this case. Processing such
             * interrupts would lead to a freeze. I don't know why.
             */
            if (reg_icr == 0xffffffff)
                  break;

            if (ifp->if_drv_flags & IFF_DRV_RUNNING) {
                  em_rxeof(adapter, -1);
                  EM_TX_LOCK(adapter);
                  em_txeof(adapter);
                  EM_TX_UNLOCK(adapter);
            }

            /* Link status change */
            if (reg_icr & (E1000_ICR_RXSEQ | E1000_ICR_LSC)) {
                  callout_stop(&adapter->timer);
                  adapter->hw.mac.get_link_status = 1;
                  e1000_check_for_link(&adapter->hw);
                  em_update_link_status(adapter);
                  /* Deal with TX cruft when link lost */
                  em_tx_purge(adapter);
                  callout_reset(&adapter->timer, hz,
                      em_local_timer, adapter);
            }

            if (reg_icr & E1000_ICR_RXO)
                  adapter->rx_overruns++;
      }
      EM_CORE_UNLOCK(adapter);

      if (ifp->if_drv_flags & IFF_DRV_RUNNING &&
          !IFQ_DRV_IS_EMPTY(&ifp->if_snd))
            em_start(ifp);
}

#else /* EM_FAST_IRQ, then fast interrupt routines only */

static void
em_handle_link(void *context, int pending)
{
      struct adapter    *adapter = context;
      struct ifnet *ifp;

      ifp = adapter->ifp;

      EM_CORE_LOCK(adapter);
      if (!(ifp->if_drv_flags & IFF_DRV_RUNNING)) {
            EM_CORE_UNLOCK(adapter);
            return;
      }

      callout_stop(&adapter->timer);
      adapter->hw.mac.get_link_status = 1;
      e1000_check_for_link(&adapter->hw);
      em_update_link_status(adapter);
      /* Deal with TX cruft when link lost */
      em_tx_purge(adapter);
      callout_reset(&adapter->timer, hz, em_local_timer, adapter);
      EM_CORE_UNLOCK(adapter);
}

#if __FreeBSD_version >= 700000
#if !defined(NET_LOCK_GIANT)
#define NET_LOCK_GIANT()
#define NET_UNLOCK_GIANT()
#endif
#endif

static void
em_handle_rxtx(void *context, int pending)
{
      struct adapter    *adapter = context;
      struct ifnet      *ifp;

      NET_LOCK_GIANT();
      ifp = adapter->ifp;

      /*
       * TODO:
       * It should be possible to run the tx clean loop without the lock.
       */
      if (ifp->if_drv_flags & IFF_DRV_RUNNING) {
            if (em_rxeof(adapter, adapter->rx_process_limit) != 0)
                  taskqueue_enqueue(adapter->tq, &adapter->rxtx_task);
            EM_TX_LOCK(adapter);
            em_txeof(adapter);

            if (!IFQ_DRV_IS_EMPTY(&ifp->if_snd))
                  em_start_locked(ifp);
            EM_TX_UNLOCK(adapter);
      }

      em_enable_intr(adapter);
      NET_UNLOCK_GIANT();
}

/*********************************************************************
 *
 *  Fast Interrupt Service routine  
 *
 *********************************************************************/
#if __FreeBSD_version < 700000
#define FILTER_STRAY
#define FILTER_HANDLED
static void
#else
static int
#endif
em_intr_fast(void *arg)
{
      struct adapter    *adapter = arg;
      struct ifnet      *ifp;
      uint32_t    reg_icr;

      ifp = adapter->ifp;

      reg_icr = E1000_READ_REG(&adapter->hw, E1000_ICR);

      /* Hot eject?  */
      if (reg_icr == 0xffffffff)
            return FILTER_STRAY;

      /* Definitely not our interrupt.  */
      if (reg_icr == 0x0)
            return FILTER_STRAY;

      /*
       * Starting with the 82571 chip, bit 31 should be used to
       * determine whether the interrupt belongs to us.
       */
      if (adapter->hw.mac.type >= e1000_82571 &&
          (reg_icr & E1000_ICR_INT_ASSERTED) == 0)
            return FILTER_STRAY;

      /*
       * Mask interrupts until the taskqueue is finished running.  This is
       * cheap, just assume that it is needed.  This also works around the
       * MSI message reordering errata on certain systems.
       */
      em_disable_intr(adapter);
      taskqueue_enqueue(adapter->tq, &adapter->rxtx_task);

      /* Link status change */
      if (reg_icr & (E1000_ICR_RXSEQ | E1000_ICR_LSC))
            taskqueue_enqueue(taskqueue_fast, &adapter->link_task);

      if (reg_icr & E1000_ICR_RXO)
            adapter->rx_overruns++;
      return FILTER_HANDLED;
}
#endif /* EM_FAST_IRQ */

/*********************************************************************
 *
 *  Media Ioctl callback
 *
 *  This routine is called whenever the user queries the status of
 *  the interface using ifconfig.
 *
 **********************************************************************/
static void
em_media_status(struct ifnet *ifp, struct ifmediareq *ifmr)
{
      struct adapter *adapter = ifp->if_softc;
      u_char fiber_type = IFM_1000_SX;

      INIT_DEBUGOUT("em_media_status: begin");

      EM_CORE_LOCK(adapter);
      e1000_check_for_link(&adapter->hw);
      em_update_link_status(adapter);

      ifmr->ifm_status = IFM_AVALID;
      ifmr->ifm_active = IFM_ETHER;

      if (!adapter->link_active) {
            EM_CORE_UNLOCK(adapter);
            return;
      }

      ifmr->ifm_status |= IFM_ACTIVE;

      if ((adapter->hw.phy.media_type == e1000_media_type_fiber) ||
          (adapter->hw.phy.media_type == e1000_media_type_internal_serdes)) {
            if (adapter->hw.mac.type == e1000_82545)
                  fiber_type = IFM_1000_LX;
            ifmr->ifm_active |= fiber_type | IFM_FDX;
      } else {
            switch (adapter->link_speed) {
            case 10:
                  ifmr->ifm_active |= IFM_10_T;
                  break;
            case 100:
                  ifmr->ifm_active |= IFM_100_TX;
                  break;
            case 1000:
                  ifmr->ifm_active |= IFM_1000_T;
                  break;
            }
            if (adapter->link_duplex == FULL_DUPLEX)
                  ifmr->ifm_active |= IFM_FDX;
            else
                  ifmr->ifm_active |= IFM_HDX;
      }
      EM_CORE_UNLOCK(adapter);
}

/*********************************************************************
 *
 *  Media Ioctl callback
 *
 *  This routine is called when the user changes speed/duplex using
 *  media/mediopt option with ifconfig.
 *
 **********************************************************************/
static int
em_media_change(struct ifnet *ifp)
{
      struct adapter *adapter = ifp->if_softc;
      struct ifmedia  *ifm = &adapter->media;

      INIT_DEBUGOUT("em_media_change: begin");

      if (IFM_TYPE(ifm->ifm_media) != IFM_ETHER)
            return (EINVAL);

      EM_CORE_LOCK(adapter);
      switch (IFM_SUBTYPE(ifm->ifm_media)) {
      case IFM_AUTO:
            adapter->hw.mac.autoneg = DO_AUTO_NEG;
            adapter->hw.phy.autoneg_advertised = AUTONEG_ADV_DEFAULT;
            break;
      case IFM_1000_LX:
      case IFM_1000_SX:
      case IFM_1000_T:
            adapter->hw.mac.autoneg = DO_AUTO_NEG;
            adapter->hw.phy.autoneg_advertised = ADVERTISE_1000_FULL;
            break;
      case IFM_100_TX:
            adapter->hw.mac.autoneg = FALSE;
            adapter->hw.phy.autoneg_advertised = 0;
            if ((ifm->ifm_media & IFM_GMASK) == IFM_FDX)
                  adapter->hw.mac.forced_speed_duplex = ADVERTISE_100_FULL;
            else
                  adapter->hw.mac.forced_speed_duplex = ADVERTISE_100_HALF;
            break;
      case IFM_10_T:
            adapter->hw.mac.autoneg = FALSE;
            adapter->hw.phy.autoneg_advertised = 0;
            if ((ifm->ifm_media & IFM_GMASK) == IFM_FDX)
                  adapter->hw.mac.forced_speed_duplex = ADVERTISE_10_FULL;
            else
                  adapter->hw.mac.forced_speed_duplex = ADVERTISE_10_HALF;
            break;
      default:
            device_printf(adapter->dev, "Unsupported media type\n");
      }

      /* As the speed/duplex settings my have changed we need to
       * reset the PHY.
       */
      adapter->hw.phy.reset_disable = FALSE;

      em_init_locked(adapter);
      EM_CORE_UNLOCK(adapter);

      return (0);
}

/*********************************************************************
 *
 *  This routine maps the mbufs to tx descriptors.
 *
 *  return 0 on success, positive on failure
 **********************************************************************/

static int
em_encap(struct adapter *adapter, struct mbuf **m_headp)
{
      bus_dma_segment_t segs[EM_MAX_SCATTER];
      bus_dmamap_t            map;
      struct em_buffer  *tx_buffer, *tx_buffer_mapped;
      struct e1000_tx_desc    *ctxd = NULL;
      struct mbuf       *m_head;
      uint32_t          txd_upper, txd_lower, txd_used, txd_saved;
      int               nsegs, i, j, first, last = 0;
      int               error, do_tso, tso_desc = 0;
#if __FreeBSD_version < 700000
      struct m_tag            *mtag;
#endif
      m_head = *m_headp;
      txd_upper = txd_lower = txd_used = txd_saved = 0;

#if __FreeBSD_version >= 700000
      do_tso = ((m_head->m_pkthdr.csum_flags & CSUM_TSO) != 0);
#else
      do_tso = 0;
#endif

        /*
         * Force a cleanup if number of TX descriptors
         * available hits the threshold
         */
      if (adapter->num_tx_desc_avail <= EM_TX_CLEANUP_THRESHOLD) {
            em_txeof(adapter);
            /* Now do we at least have a minimal? */
            if (adapter->num_tx_desc_avail <= EM_TX_OP_THRESHOLD) {
                  adapter->no_tx_desc_avail1++;
                  return (ENOBUFS);
            }
      }


      /*
       * TSO workaround: 
       *  If an mbuf is only header we need  
       *     to pull 4 bytes of data into it. 
       */
      if (do_tso && (m_head->m_len <= M_TSO_LEN)) {
            m_head = m_pullup(m_head, M_TSO_LEN + 4);
            *m_headp = m_head;
            if (m_head == NULL)
                  return (ENOBUFS);
      }

      /*
       * Map the packet for DMA
       *
       * Capture the first descriptor index,
       * this descriptor will have the index
       * of the EOP which is the only one that
       * now gets a DONE bit writeback.
       */
      first = adapter->next_avail_tx_desc;
      tx_buffer = &adapter->tx_buffer_area[first];
      tx_buffer_mapped = tx_buffer;
      map = tx_buffer->map;

      error = bus_dmamap_load_mbuf_sg(adapter->txtag, map,
          *m_headp, segs, &nsegs, BUS_DMA_NOWAIT);

      /*
       * There are two types of errors we can (try) to handle:
       * - EFBIG means the mbuf chain was too long and bus_dma ran
       *   out of segments.  Defragment the mbuf chain and try again.
       * - ENOMEM means bus_dma could not obtain enough bounce buffers
       *   at this point in time.  Defer sending and try again later.
       * All other errors, in particular EINVAL, are fatal and prevent the
       * mbuf chain from ever going through.  Drop it and report error.
       */
      if (error == EFBIG) {
            struct mbuf *m;

            m = m_defrag(*m_headp, M_DONTWAIT);
            if (m == NULL) {
                  adapter->mbuf_alloc_failed++;
                  m_freem(*m_headp);
                  *m_headp = NULL;
                  return (ENOBUFS);
            }
            *m_headp = m;

            /* Try it again */
            error = bus_dmamap_load_mbuf_sg(adapter->txtag, map,
                *m_headp, segs, &nsegs, BUS_DMA_NOWAIT);

            if (error == ENOMEM) {
                  adapter->no_tx_dma_setup++;
                  return (error);
            } else if (error != 0) {
                  adapter->no_tx_dma_setup++;
                  m_freem(*m_headp);
                  *m_headp = NULL;
                  return (error);
            }
      } else if (error == ENOMEM) {
            adapter->no_tx_dma_setup++;
            return (error);
      } else if (error != 0) {
            adapter->no_tx_dma_setup++;
            m_freem(*m_headp);
            *m_headp = NULL;
            return (error);
      }

      /*
       * TSO Hardware workaround, if this packet is not
       * TSO, and is only a single descriptor long, and
       * it follows a TSO burst, then we need to add a
       * sentinel descriptor to prevent premature writeback.
       */
      if ((do_tso == 0) && (adapter->tx_tso == TRUE)) {
            if (nsegs == 1)
                  tso_desc = TRUE;
            adapter->tx_tso = FALSE;
      }

        if (nsegs > (adapter->num_tx_desc_avail - 2)) {
                adapter->no_tx_desc_avail2++;
            bus_dmamap_unload(adapter->txtag, map);
            return (ENOBUFS);
        }
      m_head = *m_headp;

      /* Do hardware assists */
#if __FreeBSD_version >= 700000
      if (em_tso_setup(adapter, m_head, &txd_upper, &txd_lower))
            /* we need to make a final sentinel transmit desc */
            tso_desc = TRUE;
      else
#endif
       if (m_head->m_pkthdr.csum_flags & CSUM_OFFLOAD)
            em_transmit_checksum_setup(adapter,  m_head,
                &txd_upper, &txd_lower);

      i = adapter->next_avail_tx_desc;
      if (adapter->pcix_82544) 
            txd_saved = i;

      /* Set up our transmit descriptors */
      for (j = 0; j < nsegs; j++) {
            bus_size_t seg_len;
            bus_addr_t seg_addr;
            /* If adapter is 82544 and on PCIX bus */
            if(adapter->pcix_82544) {
                  DESC_ARRAY  desc_array;
                  uint32_t    array_elements, counter;
                  /*
                   * Check the Address and Length combination and
                   * split the data accordingly
                   */
                  array_elements = em_fill_descriptors(segs[j].ds_addr,
                      segs[j].ds_len, &desc_array);
                  for (counter = 0; counter < array_elements; counter++) {
                        if (txd_used == adapter->num_tx_desc_avail) {
                              adapter->next_avail_tx_desc = txd_saved;
                              adapter->no_tx_desc_avail2++;
                              bus_dmamap_unload(adapter->txtag, map);
                              return (ENOBUFS);
                        }
                        tx_buffer = &adapter->tx_buffer_area[i];
                        ctxd = &adapter->tx_desc_base[i];
                        ctxd->buffer_addr = htole64(
                            desc_array.descriptor[counter].address);
                        ctxd->lower.data = htole32(
                            (adapter->txd_cmd | txd_lower | (uint16_t) 
                            desc_array.descriptor[counter].length));
                        ctxd->upper.data =
                            htole32((txd_upper));
                        last = i;
                        if (++i == adapter->num_tx_desc)
                                         i = 0;
                        tx_buffer->m_head = NULL;
                        tx_buffer->next_eop = -1;
                        txd_used++;
                        }
            } else {
                  tx_buffer = &adapter->tx_buffer_area[i];
                  ctxd = &adapter->tx_desc_base[i];
                  seg_addr = segs[j].ds_addr;
                  seg_len  = segs[j].ds_len;
                  /*
                  ** TSO Workaround:
                  ** If this is the last descriptor, we want to
                  ** split it so we have a small final sentinel
                  */
                  if (tso_desc && (j == (nsegs -1)) && (seg_len > 8)) {
                        seg_len -= 4;
                        ctxd->buffer_addr = htole64(seg_addr);
                        ctxd->lower.data = htole32(
                        adapter->txd_cmd | txd_lower | seg_len);
                        ctxd->upper.data =
                            htole32(txd_upper);
                        if (++i == adapter->num_tx_desc)
                              i = 0;
                        /* Now make the sentinel */   
                        ++txd_used; /* using an extra txd */
                        ctxd = &adapter->tx_desc_base[i];
                        tx_buffer = &adapter->tx_buffer_area[i];
                        ctxd->buffer_addr =
                            htole64(seg_addr + seg_len);
                        ctxd->lower.data = htole32(
                        adapter->txd_cmd | txd_lower | 4);
                        ctxd->upper.data =
                            htole32(txd_upper);
                        last = i;
                        if (++i == adapter->num_tx_desc)
                              i = 0;
                  } else {
                        ctxd->buffer_addr = htole64(seg_addr);
                        ctxd->lower.data = htole32(
                        adapter->txd_cmd | txd_lower | seg_len);
                        ctxd->upper.data =
                            htole32(txd_upper);
                        last = i;
                        if (++i == adapter->num_tx_desc)
                              i = 0;
                  }
                  tx_buffer->m_head = NULL;
                  tx_buffer->next_eop = -1;
            }
      }

      adapter->next_avail_tx_desc = i;
      if (adapter->pcix_82544)
            adapter->num_tx_desc_avail -= txd_used;
      else {
            adapter->num_tx_desc_avail -= nsegs;
            if (tso_desc) /* TSO used an extra for sentinel */
                  adapter->num_tx_desc_avail -= txd_used;
      }

        /*
      ** Handle VLAN tag, this is the
      ** biggest difference between 
      ** 6.x and 7
      */
#if __FreeBSD_version < 700000
        /* Find out if we are in vlan mode. */
        mtag = VLAN_OUTPUT_TAG(ifp, m_head);
        if (mtag != NULL) {
                ctxd->upper.fields.special =
                    htole16(VLAN_TAG_VALUE(mtag));
#else /* FreeBSD 7 */
      if (m_head->m_flags & M_VLANTAG) {
            /* Set the vlan id. */
            ctxd->upper.fields.special =
                htole16(m_head->m_pkthdr.ether_vtag);
#endif
                /* Tell hardware to add tag */
                ctxd->lower.data |= htole32(E1000_TXD_CMD_VLE);
        }

        tx_buffer->m_head = m_head;
      tx_buffer_mapped->map = tx_buffer->map;
      tx_buffer->map = map;
        bus_dmamap_sync(adapter->txtag, map, BUS_DMASYNC_PREWRITE);

        /*
         * Last Descriptor of Packet
       * needs End Of Packet (EOP)
       * and Report Status (RS)
         */
        ctxd->lower.data |=
          htole32(E1000_TXD_CMD_EOP | E1000_TXD_CMD_RS);
      /*
       * Keep track in the first buffer which
       * descriptor will be written back
       */
      tx_buffer = &adapter->tx_buffer_area[first];
      tx_buffer->next_eop = last;

      /*
       * Advance the Transmit Descriptor Tail (TDT), this tells the E1000
       * that this frame is available to transmit.
       */
      bus_dmamap_sync(adapter->txdma.dma_tag, adapter->txdma.dma_map,
          BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
      if (adapter->hw.mac.type == e1000_82547 &&
          adapter->link_duplex == HALF_DUPLEX)
            em_82547_move_tail(adapter);
      else {
            E1000_WRITE_REG(&adapter->hw, E1000_TDT(0), i);
            if (adapter->hw.mac.type == e1000_82547)
                  em_82547_update_fifo_head(adapter,
                      m_head->m_pkthdr.len);
      }

      return (0);
}

/*********************************************************************
 *
 *  This routine maps the mbufs to Advanced TX descriptors.
 *  used by the 82575 adapter. It also needs no workarounds.
 *  
 **********************************************************************/

static int
em_adv_encap(struct adapter *adapter, struct mbuf **m_headp)
{
      bus_dma_segment_t segs[EM_MAX_SCATTER];
      bus_dmamap_t            map;
      struct em_buffer  *tx_buffer, *tx_buffer_mapped;
      union e1000_adv_tx_desc *txd = NULL;
      struct mbuf       *m_head;
      u32               olinfo_status = 0, cmd_type_len = 0;
      int               nsegs, i, j, error, first, last = 0;
#if __FreeBSD_version < 700000
      struct m_tag            *mtag;
#else
      u32               paylen = 0;
#endif

      m_head = *m_headp;


      /* Set basic descriptor constants */
      cmd_type_len |= E1000_ADVTXD_DTYP_DATA;
      cmd_type_len |= E1000_ADVTXD_DCMD_IFCS | E1000_ADVTXD_DCMD_DEXT;
#if __FreeBSD_version < 700000
        mtag = VLAN_OUTPUT_TAG(ifp, m_head);
        if (mtag != NULL)
#else
      if (m_head->m_flags & M_VLANTAG)
#endif
            cmd_type_len |= E1000_ADVTXD_DCMD_VLE;

        /*
         * Force a cleanup if number of TX descriptors
         * available hits the threshold
         */
      if (adapter->num_tx_desc_avail <= EM_TX_CLEANUP_THRESHOLD) {
            em_txeof(adapter);
            /* Now do we at least have a minimal? */
            if (adapter->num_tx_desc_avail <= EM_TX_OP_THRESHOLD) {
                  adapter->no_tx_desc_avail1++;
                  return (ENOBUFS);
            }
      }

      /*
         * Map the packet for DMA.
       *
       * Capture the first descriptor index,
       * this descriptor will have the index
       * of the EOP which is the only one that
       * now gets a DONE bit writeback.
       */
      first = adapter->next_avail_tx_desc;
      tx_buffer = &adapter->tx_buffer_area[first];
      tx_buffer_mapped = tx_buffer;
      map = tx_buffer->map;

      error = bus_dmamap_load_mbuf_sg(adapter->txtag, map,
          *m_headp, segs, &nsegs, BUS_DMA_NOWAIT);

      if (error == EFBIG) {
            struct mbuf *m;

            m = m_defrag(*m_headp, M_DONTWAIT);
            if (m == NULL) {
                  adapter->mbuf_alloc_failed++;
                  m_freem(*m_headp);
                  *m_headp = NULL;
                  return (ENOBUFS);
            }
            *m_headp = m;

            /* Try it again */
            error = bus_dmamap_load_mbuf_sg(adapter->txtag, map,
                *m_headp, segs, &nsegs, BUS_DMA_NOWAIT);

            if (error == ENOMEM) {
                  adapter->no_tx_dma_setup++;
                  return (error);
            } else if (error != 0) {
                  adapter->no_tx_dma_setup++;
                  m_freem(*m_headp);
                  *m_headp = NULL;
                  return (error);
            }
      } else if (error == ENOMEM) {
            adapter->no_tx_dma_setup++;
            return (error);
      } else if (error != 0) {
            adapter->no_tx_dma_setup++;
            m_freem(*m_headp);
            *m_headp = NULL;
            return (error);
      }

      /* Check again to be sure we have enough descriptors */
        if (nsegs > (adapter->num_tx_desc_avail - 2)) {
                adapter->no_tx_desc_avail2++;
            bus_dmamap_unload(adapter->txtag, map);
            return (ENOBUFS);
        }
      m_head = *m_headp;

        /*
         * Set up the context descriptor:
         * used when any hardware offload is done.
       * This includes CSUM, VLAN, and TSO. It
       * will use the first descriptor.
         */
#if __FreeBSD_version >= 700000
      /* First try TSO */
      if (em_tso_adv_setup(adapter, m_head, &paylen)) {
            cmd_type_len |= E1000_ADVTXD_DCMD_TSE;
            olinfo_status |= E1000_TXD_POPTS_IXSM << 8;
            olinfo_status |= E1000_TXD_POPTS_TXSM << 8;
            olinfo_status |= paylen << E1000_ADVTXD_PAYLEN_SHIFT;
      } else
#endif
            /* Do all other context descriptor setup */
            if (em_tx_adv_ctx_setup(adapter, m_head))
                  olinfo_status |= E1000_TXD_POPTS_TXSM << 8;

      /* Set up our transmit descriptors */
      i = adapter->next_avail_tx_desc;
      for (j = 0; j < nsegs; j++) {
            bus_size_t seg_len;
            bus_addr_t seg_addr;

            tx_buffer = &adapter->tx_buffer_area[i];
            txd = (union e1000_adv_tx_desc *)&adapter->tx_desc_base[i];
            seg_addr = segs[j].ds_addr;
            seg_len  = segs[j].ds_len;

            txd->read.buffer_addr = htole64(seg_addr);
            txd->read.cmd_type_len = htole32(
                adapter->txd_cmd | cmd_type_len | seg_len);
            txd->read.olinfo_status = htole32(olinfo_status);
            last = i;
            if (++i == adapter->num_tx_desc)
                  i = 0;
            tx_buffer->m_head = NULL;
            tx_buffer->next_eop = -1;
      }

      adapter->next_avail_tx_desc = i;
      adapter->num_tx_desc_avail -= nsegs;

        tx_buffer->m_head = m_head;
      tx_buffer_mapped->map = tx_buffer->map;
      tx_buffer->map = map;
        bus_dmamap_sync(adapter->txtag, map, BUS_DMASYNC_PREWRITE);

        /*
         * Last Descriptor of Packet
       * needs End Of Packet (EOP)
       * and Report Status (RS)
         */
        txd->read.cmd_type_len |=
          htole32(E1000_TXD_CMD_EOP | E1000_TXD_CMD_RS);
      /*
       * Keep track in the first buffer which
       * descriptor will be written back
       */
      tx_buffer = &adapter->tx_buffer_area[first];
      tx_buffer->next_eop = last;

      /*
       * Advance the Transmit Descriptor Tail (TDT), this tells the E1000
       * that this frame is available to transmit.
       */
      bus_dmamap_sync(adapter->txdma.dma_tag, adapter->txdma.dma_map,
          BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
      E1000_WRITE_REG(&adapter->hw, E1000_TDT(0), i);

      return (0);

}

/*********************************************************************
 *
 * 82547 workaround to avoid controller hang in half-duplex environment.
 * The workaround is to avoid queuing a large packet that would span
 * the internal Tx FIFO ring boundary. We need to reset the FIFO pointers
 * in this case. We do that only when FIFO is quiescent.
 *
 **********************************************************************/
static void
em_82547_move_tail(void *arg)
{
      struct adapter *adapter = arg;
      uint16_t hw_tdt;
      uint16_t sw_tdt;
      struct e1000_tx_desc *tx_desc;
      uint16_t length = 0;
      boolean_t eop = 0;

      EM_TX_LOCK_ASSERT(adapter);

      hw_tdt = E1000_READ_REG(&adapter->hw, E1000_TDT(0));
      sw_tdt = adapter->next_avail_tx_desc;
      
      while (hw_tdt != sw_tdt) {
            tx_desc = &adapter->tx_desc_base[hw_tdt];
            length += tx_desc->lower.flags.length;
            eop = tx_desc->lower.data & E1000_TXD_CMD_EOP;
            if (++hw_tdt == adapter->num_tx_desc)
                  hw_tdt = 0;

            if (eop) {
                  if (em_82547_fifo_workaround(adapter, length)) {
                        adapter->tx_fifo_wrk_cnt++;
                        callout_reset(&adapter->tx_fifo_timer, 1,
                              em_82547_move_tail, adapter);
                        break;
                  }
                  E1000_WRITE_REG(&adapter->hw, E1000_TDT(0), hw_tdt);
                  em_82547_update_fifo_head(adapter, length);
                  length = 0;
            }
      }     
}

static int
em_82547_fifo_workaround(struct adapter *adapter, int len)
{     
      int fifo_space, fifo_pkt_len;

      fifo_pkt_len = roundup2(len + EM_FIFO_HDR, EM_FIFO_HDR);

      if (adapter->link_duplex == HALF_DUPLEX) {
            fifo_space = adapter->tx_fifo_size - adapter->tx_fifo_head;

            if (fifo_pkt_len >= (EM_82547_PKT_THRESH + fifo_space)) {
                  if (em_82547_tx_fifo_reset(adapter))
                        return (0);
                  else
                        return (1);
            }
      }

      return (0);
}

static void
em_82547_update_fifo_head(struct adapter *adapter, int len)
{
      int fifo_pkt_len = roundup2(len + EM_FIFO_HDR, EM_FIFO_HDR);
      
      /* tx_fifo_head is always 16 byte aligned */
      adapter->tx_fifo_head += fifo_pkt_len;
      if (adapter->tx_fifo_head >= adapter->tx_fifo_size) {
            adapter->tx_fifo_head -= adapter->tx_fifo_size;
      }
}


static int
em_82547_tx_fifo_reset(struct adapter *adapter)
{
      uint32_t tctl;

      if ((E1000_READ_REG(&adapter->hw, E1000_TDT(0)) ==
          E1000_READ_REG(&adapter->hw, E1000_TDH(0))) &&
          (E1000_READ_REG(&adapter->hw, E1000_TDFT) == 
          E1000_READ_REG(&adapter->hw, E1000_TDFH)) &&
          (E1000_READ_REG(&adapter->hw, E1000_TDFTS) ==
          E1000_READ_REG(&adapter->hw, E1000_TDFHS)) &&
          (E1000_READ_REG(&adapter->hw, E1000_TDFPC) == 0)) {
            /* Disable TX unit */
            tctl = E1000_READ_REG(&adapter->hw, E1000_TCTL);
            E1000_WRITE_REG(&adapter->hw, E1000_TCTL,
                tctl & ~E1000_TCTL_EN);

            /* Reset FIFO pointers */
            E1000_WRITE_REG(&adapter->hw, E1000_TDFT,
                adapter->tx_head_addr);
            E1000_WRITE_REG(&adapter->hw, E1000_TDFH,
                adapter->tx_head_addr);
            E1000_WRITE_REG(&adapter->hw, E1000_TDFTS,
                adapter->tx_head_addr);
            E1000_WRITE_REG(&adapter->hw, E1000_TDFHS,
                adapter->tx_head_addr);

            /* Re-enable TX unit */
            E1000_WRITE_REG(&adapter->hw, E1000_TCTL, tctl);
            E1000_WRITE_FLUSH(&adapter->hw);

            adapter->tx_fifo_head = 0;
            adapter->tx_fifo_reset_cnt++;

            return (TRUE);
      }
      else {
            return (FALSE);
      }
}

static void
em_set_promisc(struct adapter *adapter)
{
      struct ifnet      *ifp = adapter->ifp;
      uint32_t    reg_rctl;

      reg_rctl = E1000_READ_REG(&adapter->hw, E1000_RCTL);

      if (ifp->if_flags & IFF_PROMISC) {
            reg_rctl |= (E1000_RCTL_UPE | E1000_RCTL_MPE);
            E1000_WRITE_REG(&adapter->hw, E1000_RCTL, reg_rctl);
      } else if (ifp->if_flags & IFF_ALLMULTI) {
            reg_rctl |= E1000_RCTL_MPE;
            reg_rctl &= ~E1000_RCTL_UPE;
            E1000_WRITE_REG(&adapter->hw, E1000_RCTL, reg_rctl);
      }
}

static void
em_disable_promisc(struct adapter *adapter)
{
      uint32_t    reg_rctl;

      reg_rctl = E1000_READ_REG(&adapter->hw, E1000_RCTL);

      reg_rctl &=  (~E1000_RCTL_UPE);
      reg_rctl &=  (~E1000_RCTL_MPE);
      E1000_WRITE_REG(&adapter->hw, E1000_RCTL, reg_rctl);
}


/*********************************************************************
 *  Multicast Update
 *
 *  This routine is called whenever multicast address list is updated.
 *
 **********************************************************************/

static void
em_set_multi(struct adapter *adapter)
{
      struct ifnet      *ifp = adapter->ifp;
      struct ifmultiaddr *ifma;
      uint32_t reg_rctl = 0;
      uint8_t  mta[512]; /* Largest MTS is 4096 bits */
      int mcnt = 0;

      IOCTL_DEBUGOUT("em_set_multi: begin");

      if (adapter->hw.mac.type == e1000_82542 && 
          adapter->hw.revision_id == E1000_REVISION_2) {
            reg_rctl = E1000_READ_REG(&adapter->hw, E1000_RCTL);
            if (adapter->hw.bus.pci_cmd_word & CMD_MEM_WRT_INVALIDATE)
                  e1000_pci_clear_mwi(&adapter->hw);
            reg_rctl |= E1000_RCTL_RST;
            E1000_WRITE_REG(&adapter->hw, E1000_RCTL, reg_rctl);
            msec_delay(5);
      }

      IF_ADDR_LOCK(ifp);
      TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
            if (ifma->ifma_addr->sa_family != AF_LINK)
                  continue;

            if (mcnt == MAX_NUM_MULTICAST_ADDRESSES)
                  break;

            bcopy(LLADDR((struct sockaddr_dl *)ifma->ifma_addr),
                &mta[mcnt * ETH_ADDR_LEN], ETH_ADDR_LEN);
            mcnt++;
      }
      IF_ADDR_UNLOCK(ifp);

      if (mcnt >= MAX_NUM_MULTICAST_ADDRESSES) {
            reg_rctl = E1000_READ_REG(&adapter->hw, E1000_RCTL);
            reg_rctl |= E1000_RCTL_MPE;
            E1000_WRITE_REG(&adapter->hw, E1000_RCTL, reg_rctl);
      } else
            e1000_update_mc_addr_list(&adapter->hw, mta,
                mcnt, 1, adapter->hw.mac.rar_entry_count);

      if (adapter->hw.mac.type == e1000_82542 && 
          adapter->hw.revision_id == E1000_REVISION_2) {
            reg_rctl = E1000_READ_REG(&adapter->hw, E1000_RCTL);
            reg_rctl &= ~E1000_RCTL_RST;
            E1000_WRITE_REG(&adapter->hw, E1000_RCTL, reg_rctl);
            msec_delay(5);
            if (adapter->hw.bus.pci_cmd_word & CMD_MEM_WRT_INVALIDATE)
                  e1000_pci_set_mwi(&adapter->hw);
      }
}


/*********************************************************************
 *  Timer routine
 *
 *  This routine checks for link status and updates statistics.
 *
 **********************************************************************/

static void
em_local_timer(void *arg)
{
      struct adapter    *adapter = arg;
      struct ifnet      *ifp = adapter->ifp;

      EM_CORE_LOCK_ASSERT(adapter);

      e1000_check_for_link(&adapter->hw);
      em_update_link_status(adapter);
      em_update_stats_counters(adapter);

      /* Reset LAA into RAR[0] on 82571 */
      if (e1000_get_laa_state_82571(&adapter->hw) == TRUE)
            e1000_rar_set(&adapter->hw, adapter->hw.mac.addr, 0);

      if (em_display_debug_stats && ifp->if_drv_flags & IFF_DRV_RUNNING)
            em_print_hw_stats(adapter);

      em_smartspeed(adapter);

      /*
       * Each second we check the watchdog to 
       * protect against hardware hangs.
       */
      em_watchdog(adapter);

      callout_reset(&adapter->timer, hz, em_local_timer, adapter);

}

static void
em_update_link_status(struct adapter *adapter)
{
      struct ifnet *ifp = adapter->ifp;
      device_t dev = adapter->dev;

      if (E1000_READ_REG(&adapter->hw, E1000_STATUS) &
          E1000_STATUS_LU) {
            if (adapter->link_active == 0) {
                  e1000_get_speed_and_duplex(&adapter->hw, 
                      &adapter->link_speed, &adapter->link_duplex);
                  /* Check if we must disable SPEED_MODE bit on PCI-E */
                  if ((adapter->link_speed != SPEED_1000) &&
                      ((adapter->hw.mac.type == e1000_82571) ||
                      (adapter->hw.mac.type == e1000_82572))) {
                        int tarc0;

                        tarc0 = E1000_READ_REG(&adapter->hw,
                            E1000_TARC(0));
                        tarc0 &= ~SPEED_MODE_BIT;
                        E1000_WRITE_REG(&adapter->hw,
                            E1000_TARC(0), tarc0);
                  }
                  if (bootverbose)
                        device_printf(dev, "Link is up %d Mbps %s\n",
                            adapter->link_speed,
                            ((adapter->link_duplex == FULL_DUPLEX) ?
                            "Full Duplex" : "Half Duplex"));
                  adapter->link_active = 1;
                  adapter->smartspeed = 0;
                  ifp->if_baudrate = adapter->link_speed * 1000000;
                  if_link_state_change(ifp, LINK_STATE_UP);
            }
      } else {
            if (adapter->link_active == 1) {
                  ifp->if_baudrate = adapter->link_speed = 0;
                  adapter->link_duplex = 0;
                  if (bootverbose)
                        device_printf(dev, "Link is Down\n");
                  adapter->link_active = 0;
                  if_link_state_change(ifp, LINK_STATE_DOWN);
            }
      }
}

/*********************************************************************
 *
 *  This routine disables all traffic on the adapter by issuing a
 *  global reset on the MAC and deallocates TX/RX buffers.
 *
 **********************************************************************/

static void
em_stop(void *arg)
{
      struct adapter    *adapter = arg;
      struct ifnet      *ifp = adapter->ifp;

      EM_CORE_LOCK_ASSERT(adapter);

      INIT_DEBUGOUT("em_stop: begin");

      em_disable_intr(adapter);
      callout_stop(&adapter->timer);
      callout_stop(&adapter->tx_fifo_timer);

      /* Tell the stack that the interface is no longer active */
      ifp->if_drv_flags &= ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);

      e1000_reset_hw(&adapter->hw);
      if (adapter->hw.mac.type >= e1000_82544)
            E1000_WRITE_REG(&adapter->hw, E1000_WUC, 0);
}


/*********************************************************************
 *
 *  Determine hardware revision.
 *
 **********************************************************************/
static void
em_identify_hardware(struct adapter *adapter)
{
      device_t dev = adapter->dev;

      /* Make sure our PCI config space has the necessary stuff set */
      adapter->hw.bus.pci_cmd_word = pci_read_config(dev, PCIR_COMMAND, 2);
      if (!((adapter->hw.bus.pci_cmd_word & PCIM_CMD_BUSMASTEREN) &&
          (adapter->hw.bus.pci_cmd_word & PCIM_CMD_MEMEN))) {
            device_printf(dev, "Memory Access and/or Bus Master bits "
                "were not set!\n");
            adapter->hw.bus.pci_cmd_word |=
            (PCIM_CMD_BUSMASTEREN | PCIM_CMD_MEMEN);
            pci_write_config(dev, PCIR_COMMAND,
                adapter->hw.bus.pci_cmd_word, 2);
      }

      /* Save off the information about this board */
      adapter->hw.vendor_id = pci_get_vendor(dev);
      adapter->hw.device_id = pci_get_device(dev);
      adapter->hw.revision_id = pci_read_config(dev, PCIR_REVID, 1);
      adapter->hw.subsystem_vendor_id =
          pci_read_config(dev, PCIR_SUBVEND_0, 2);
      adapter->hw.subsystem_device_id =
          pci_read_config(dev, PCIR_SUBDEV_0, 2);

      /* Do Shared Code Init and Setup */
      if (e1000_set_mac_type(&adapter->hw)) {
            device_printf(dev, "Setup init failure\n");
            return;
      }
}

static int
em_allocate_pci_resources(struct adapter *adapter)
{
      device_t    dev = adapter->dev;
      int         val, rid;

      rid = PCIR_BAR(0);
      adapter->res_memory = bus_alloc_resource_any(dev, SYS_RES_MEMORY,
          &rid, RF_ACTIVE);
      if (adapter->res_memory == NULL) {
            device_printf(dev, "Unable to allocate bus resource: memory\n");
            return (ENXIO);
      }
      adapter->osdep.mem_bus_space_tag =
          rman_get_bustag(adapter->res_memory);
      adapter->osdep.mem_bus_space_handle =
          rman_get_bushandle(adapter->res_memory);
      adapter->hw.hw_addr = (uint8_t *)&adapter->osdep.mem_bus_space_handle;

      /* Only older adapters use IO mapping */
      if ((adapter->hw.mac.type > e1000_82543) &&
          (adapter->hw.mac.type < e1000_82571)) {
            /* Figure our where our IO BAR is ? */
            for (rid = PCIR_BAR(0); rid < PCIR_CIS;) {
                  val = pci_read_config(dev, rid, 4);
                  if (EM_BAR_TYPE(val) == EM_BAR_TYPE_IO) {
                        adapter->io_rid = rid;
                        break;
                  }
                  rid += 4;
                  /* check for 64bit BAR */
                  if (EM_BAR_MEM_TYPE(val) == EM_BAR_MEM_TYPE_64BIT)
                        rid += 4;
            }
            if (rid >= PCIR_CIS) {
                  device_printf(dev, "Unable to locate IO BAR\n");
                  return (ENXIO);
            }
            adapter->res_ioport = bus_alloc_resource_any(dev,
                SYS_RES_IOPORT, &adapter->io_rid, RF_ACTIVE);
            if (adapter->res_ioport == NULL) {
                  device_printf(dev, "Unable to allocate bus resource: "
                      "ioport\n");
                  return (ENXIO);
            }
            adapter->hw.io_base = 0;
            adapter->osdep.io_bus_space_tag =
                rman_get_bustag(adapter->res_ioport);
            adapter->osdep.io_bus_space_handle =
                rman_get_bushandle(adapter->res_ioport);
      }

      /*
       * Setup MSI/X or MSI if PCI Express
       * only the latest can use MSI/X and
       * real support for it is forthcoming
       */
      adapter->msi = 0; /* Set defaults */
      rid = 0x0;

#if __FreeBSD_version > 602111      /* MSI support is present */
      /* This will setup either MSI/X or MSI */
      if (em_setup_msix(adapter))
            rid = 1;
#endif      /* FreeBSD_version */

      adapter->res_interrupt = bus_alloc_resource_any(dev,
          SYS_RES_IRQ, &rid, RF_SHAREABLE | RF_ACTIVE);
      if (adapter->res_interrupt == NULL) {
            device_printf(dev, "Unable to allocate bus resource: "
                "interrupt\n");
            return (ENXIO);
      }

      adapter->hw.back = &adapter->osdep;

      return (0);
}

/*********************************************************************
 *
 *  Setup the appropriate Interrupt handlers.
 *
 **********************************************************************/
int
em_allocate_intr(struct adapter *adapter)
{
      device_t dev = adapter->dev;
      int error;

      /* Manually turn off all interrupts */
      E1000_WRITE_REG(&adapter->hw, E1000_IMC, 0xffffffff);

#ifndef EM_FAST_IRQ
      /* We do Legacy setup */
      if (adapter->int_handler_tag == NULL &&
          (error = bus_setup_intr(dev, adapter->res_interrupt,
#if __FreeBSD_version > 700000
          INTR_TYPE_NET | INTR_MPSAFE, NULL, em_intr, adapter,
#else /* 6.X */
          INTR_TYPE_NET | INTR_MPSAFE, em_intr, adapter,
#endif
          &adapter->int_handler_tag)) != 0) {
            device_printf(dev, "Failed to register interrupt handler");
            return (error);
      }

#else /* FAST_IRQ */
      /*
       * Try allocating a fast interrupt and the associated deferred
       * processing contexts.
       */
      TASK_INIT(&adapter->rxtx_task, 0, em_handle_rxtx, adapter);
      TASK_INIT(&adapter->link_task, 0, em_handle_link, adapter);
      adapter->tq = taskqueue_create_fast("em_taskq", M_NOWAIT,
          taskqueue_thread_enqueue, &adapter->tq);
      taskqueue_start_threads(&adapter->tq, 1, PI_NET, "%s taskq",
          device_get_nameunit(adapter->dev));
#if __FreeBSD_version < 700000
      if ((error = bus_setup_intr(dev, adapter->res_interrupt,
          INTR_TYPE_NET | INTR_FAST, em_intr_fast, adapter,
#else
      if ((error = bus_setup_intr(dev, adapter->res_interrupt,
          INTR_TYPE_NET, em_intr_fast, NULL, adapter,
#endif
          &adapter->int_handler_tag)) != 0) {
            device_printf(dev, "Failed to register fast interrupt "
                      "handler: %d\n", error);
            taskqueue_free(adapter->tq);
            adapter->tq = NULL;
            return (error);
      }
#endif  /* EM_FAST_IRQ */

      em_enable_intr(adapter);
      return (0);
}

static void
em_free_intr(struct adapter *adapter)
{
      device_t dev = adapter->dev;

      if (adapter->res_interrupt != NULL) {
            bus_teardown_intr(dev, adapter->res_interrupt,
                  adapter->int_handler_tag);
            adapter->int_handler_tag = NULL;
      }
      if (adapter->tq != NULL) {
            taskqueue_drain(adapter->tq, &adapter->rxtx_task);
            taskqueue_drain(taskqueue_fast, &adapter->link_task);
            taskqueue_free(adapter->tq);
            adapter->tq = NULL;
      }
}

static void
em_free_pci_resources(struct adapter *adapter)
{
      device_t dev = adapter->dev;

      if (adapter->res_interrupt != NULL)
            bus_release_resource(dev, SYS_RES_IRQ,
                adapter->msi ? 1 : 0, adapter->res_interrupt);

#if __FreeBSD_version > 602111      /* MSI support is present */
      if (adapter->msix_mem != NULL)
            bus_release_resource(dev, SYS_RES_MEMORY,
                PCIR_BAR(EM_MSIX_BAR), adapter->msix_mem);

      if (adapter->msi)
            pci_release_msi(dev);
#endif      /* FreeBSD_version */

      if (adapter->res_memory != NULL)
            bus_release_resource(dev, SYS_RES_MEMORY,
                PCIR_BAR(0), adapter->res_memory);

      if (adapter->flash_mem != NULL)
            bus_release_resource(dev, SYS_RES_MEMORY,
                EM_FLASH, adapter->flash_mem);

      if (adapter->res_ioport != NULL)
            bus_release_resource(dev, SYS_RES_IOPORT,
                adapter->io_rid, adapter->res_ioport);
}

#if __FreeBSD_version > 602111      /* MSI support is present */
/*
 * Setup MSI/X
 */
static bool
em_setup_msix(struct adapter *adapter)
{
      device_t dev = adapter->dev;
      int rid, val;

      if (adapter->hw.mac.type < e1000_82571)
            return (FALSE);

      /* First try MSI/X if possible */
      if (adapter->hw.mac.type >= e1000_82575) {
            rid = PCIR_BAR(EM_MSIX_BAR);
            adapter->msix_mem = bus_alloc_resource_any(dev,
                SYS_RES_MEMORY, &rid, RF_ACTIVE);
                  if (!adapter->msix_mem) {
                  /* May not be enabled */
                        device_printf(adapter->dev,
                      "Unable to map MSIX table \n");
                  goto msi;
                  }
            val = pci_msix_count(dev); 
            if ((val) && pci_alloc_msix(dev, &val) == 0) {
                        adapter->msi = 1;
                        device_printf(adapter->dev,"Using MSIX interrupts\n");
                  return (TRUE);
            }
      }
msi:
            val = pci_msi_count(dev);
            if (val == 1 && pci_alloc_msi(dev, &val) == 0) {
                  adapter->msi = 1;
                  device_printf(adapter->dev,"Using MSI interrupts\n");
            return (TRUE);
      } 
      return (FALSE);
}
#endif      /* FreeBSD_version */

/*********************************************************************
 *
 *  Initialize the hardware to a configuration
 *  as specified by the adapter structure.
 *
 **********************************************************************/
static int
em_hardware_init(struct adapter *adapter)
{
      device_t dev = adapter->dev;
      uint16_t rx_buffer_size;

      INIT_DEBUGOUT("em_hardware_init: begin");

      /* Issue a global reset */
      e1000_reset_hw(&adapter->hw);

      /* Get control from any management/hw control */
      if (((adapter->hw.mac.type == e1000_82573) ||
          (adapter->hw.mac.type == e1000_ich8lan) ||
          (adapter->hw.mac.type == e1000_ich9lan)) &&
          e1000_check_mng_mode(&adapter->hw))
            em_get_hw_control(adapter);

      /* When hardware is reset, fifo_head is also reset */
      adapter->tx_fifo_head = 0;

      /* Set up smart power down as default off on newer adapters. */
      if (!em_smart_pwr_down && (adapter->hw.mac.type == e1000_82571 ||
          adapter->hw.mac.type == e1000_82572)) {
            uint16_t phy_tmp = 0;

            /* Speed up time to link by disabling smart power down. */
            e1000_read_phy_reg(&adapter->hw,
                IGP02E1000_PHY_POWER_MGMT, &phy_tmp);
            phy_tmp &= ~IGP02E1000_PM_SPD;
            e1000_write_phy_reg(&adapter->hw,
                IGP02E1000_PHY_POWER_MGMT, phy_tmp);
      }

      /*
       * These parameters control the automatic generation (Tx) and
       * response (Rx) to Ethernet PAUSE frames.
       * - High water mark should allow for at least two frames to be
       *   received after sending an XOFF.
       * - Low water mark works best when it is very near the high water mark.
       *   This allows the receiver to restart by sending XON when it has
       *   drained a bit. Here we use an arbitary value of 1500 which will
       *   restart after one full frame is pulled from the buffer. There
       *   could be several smaller frames in the buffer and if so they will
       *   not trigger the XON until their total number reduces the buffer
       *   by 1500.
       * - The pause time is fairly large at 1000 x 512ns = 512 usec.
       */
      rx_buffer_size = ((E1000_READ_REG(&adapter->hw, E1000_PBA) &
          0xffff) << 10 );

      adapter->hw.fc.high_water = rx_buffer_size -
          roundup2(adapter->max_frame_size, 1024);
      adapter->hw.fc.low_water = adapter->hw.fc.high_water - 1500;

      if (adapter->hw.mac.type == e1000_80003es2lan)
            adapter->hw.fc.pause_time = 0xFFFF;
      else
            adapter->hw.fc.pause_time = EM_FC_PAUSE_TIME;
      adapter->hw.fc.send_xon = TRUE;
      adapter->hw.fc.type = e1000_fc_full;

      if (e1000_init_hw(&adapter->hw) < 0) {
            device_printf(dev, "Hardware Initialization Failed\n");
            return (EIO);
      }

      e1000_check_for_link(&adapter->hw);

      return (0);
}

/*********************************************************************
 *
 *  Setup networking device structure and register an interface.
 *
 **********************************************************************/
static void
em_setup_interface(device_t dev, struct adapter *adapter)
{
      struct ifnet   *ifp;

      INIT_DEBUGOUT("em_setup_interface: begin");

      ifp = adapter->ifp = if_alloc(IFT_ETHER);
      if (ifp == NULL)
            panic("%s: can not if_alloc()", device_get_nameunit(dev));
      if_initname(ifp, device_get_name(dev), device_get_unit(dev));
      ifp->if_mtu = ETHERMTU;
      ifp->if_init =  em_init;
      ifp->if_softc = adapter;
      ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
      ifp->if_ioctl = em_ioctl;
      ifp->if_start = em_start;
      IFQ_SET_MAXLEN(&ifp->if_snd, adapter->num_tx_desc - 1);
      ifp->if_snd.ifq_drv_maxlen = adapter->num_tx_desc - 1;
      IFQ_SET_READY(&ifp->if_snd);

      ether_ifattach(ifp, adapter->hw.mac.addr);

      ifp->if_capabilities = ifp->if_capenable = 0;

      if (adapter->hw.mac.type >= e1000_82543) {
            int version_cap;
#if __FreeBSD_version < 700000
            version_cap = IFCAP_HWCSUM;
#else
            version_cap = IFCAP_HWCSUM | IFCAP_VLAN_HWCSUM;
#endif
            ifp->if_capabilities |= version_cap;
            ifp->if_capenable |= version_cap;
      }

#if __FreeBSD_version >= 700000
      /* Identify TSO capable adapters */
      if ((adapter->hw.mac.type > e1000_82544) &&
          (adapter->hw.mac.type != e1000_82547))
            ifp->if_capabilities |= IFCAP_TSO4;
      /*
       * By default only enable on PCI-E, this
       * can be overriden by ifconfig.
       */
      if (adapter->hw.mac.type >= e1000_82571)
            ifp->if_capenable |= IFCAP_TSO4;
#endif

      /*
       * Tell the upper layer(s) we support long frames.
       */
      ifp->if_data.ifi_hdrlen = sizeof(struct ether_vlan_header);
      ifp->if_capabilities |= IFCAP_VLAN_HWTAGGING | IFCAP_VLAN_MTU;
      ifp->if_capenable |= IFCAP_VLAN_HWTAGGING | IFCAP_VLAN_MTU;

#ifdef DEVICE_POLLING
      ifp->if_capabilities |= IFCAP_POLLING;
#endif

      /*
       * Specify the media types supported by this adapter and register
       * callbacks to update media and link information
       */
      ifmedia_init(&adapter->media, IFM_IMASK,
          em_media_change, em_media_status);
      if ((adapter->hw.phy.media_type == e1000_media_type_fiber) ||
          (adapter->hw.phy.media_type == e1000_media_type_internal_serdes)) {
            u_char fiber_type = IFM_1000_SX;    /* default type */

            if (adapter->hw.mac.type == e1000_82545)
                  fiber_type = IFM_1000_LX;
            ifmedia_add(&adapter->media, IFM_ETHER | fiber_type | IFM_FDX, 
                      0, NULL);
            ifmedia_add(&adapter->media, IFM_ETHER | fiber_type, 0, NULL);
      } else {
            ifmedia_add(&adapter->media, IFM_ETHER | IFM_10_T, 0, NULL);
            ifmedia_add(&adapter->media, IFM_ETHER | IFM_10_T | IFM_FDX,
                      0, NULL);
            ifmedia_add(&adapter->media, IFM_ETHER | IFM_100_TX,
                      0, NULL);
            ifmedia_add(&adapter->media, IFM_ETHER | IFM_100_TX | IFM_FDX,
                      0, NULL);
            if (adapter->hw.phy.type != e1000_phy_ife) {
                  ifmedia_add(&adapter->media,
                        IFM_ETHER | IFM_1000_T | IFM_FDX, 0, NULL);
                  ifmedia_add(&adapter->media,
                        IFM_ETHER | IFM_1000_T, 0, NULL);
            }
      }
      ifmedia_add(&adapter->media, IFM_ETHER | IFM_AUTO, 0, NULL);
      ifmedia_set(&adapter->media, IFM_ETHER | IFM_AUTO);
}


/*********************************************************************
 *
 *  Workaround for SmartSpeed on 82541 and 82547 controllers
 *
 **********************************************************************/
static void
em_smartspeed(struct adapter *adapter)
{
      uint16_t phy_tmp;

      if (adapter->link_active || (adapter->hw.phy.type != e1000_phy_igp) ||
          adapter->hw.mac.autoneg == 0 ||
          (adapter->hw.phy.autoneg_advertised & ADVERTISE_1000_FULL) == 0)
            return;

      if (adapter->smartspeed == 0) {
            /* If Master/Slave config fault is asserted twice,
             * we assume back-to-back */
            e1000_read_phy_reg(&adapter->hw, PHY_1000T_STATUS, &phy_tmp);
            if (!(phy_tmp & SR_1000T_MS_CONFIG_FAULT))
                  return;
            e1000_read_phy_reg(&adapter->hw, PHY_1000T_STATUS, &phy_tmp);
            if (phy_tmp & SR_1000T_MS_CONFIG_FAULT) {
                  e1000_read_phy_reg(&adapter->hw, PHY_1000T_CTRL, &phy_tmp);
                  if(phy_tmp & CR_1000T_MS_ENABLE) {
                        phy_tmp &= ~CR_1000T_MS_ENABLE;
                        e1000_write_phy_reg(&adapter->hw, PHY_1000T_CTRL,
                            phy_tmp);
                        adapter->smartspeed++;
                        if(adapter->hw.mac.autoneg &&
                           !e1000_phy_setup_autoneg(&adapter->hw) &&
                           !e1000_read_phy_reg(&adapter->hw, PHY_CONTROL,
                            &phy_tmp)) {
                              phy_tmp |= (MII_CR_AUTO_NEG_EN |
                                        MII_CR_RESTART_AUTO_NEG);
                              e1000_write_phy_reg(&adapter->hw, PHY_CONTROL,
                                  phy_tmp);
                        }
                  }
            }
            return;
      } else if(adapter->smartspeed == EM_SMARTSPEED_DOWNSHIFT) {
            /* If still no link, perhaps using 2/3 pair cable */
            e1000_read_phy_reg(&adapter->hw, PHY_1000T_CTRL, &phy_tmp);
            phy_tmp |= CR_1000T_MS_ENABLE;
            e1000_write_phy_reg(&adapter->hw, PHY_1000T_CTRL, phy_tmp);
            if(adapter->hw.mac.autoneg &&
               !e1000_phy_setup_autoneg(&adapter->hw) &&
               !e1000_read_phy_reg(&adapter->hw, PHY_CONTROL, &phy_tmp)) {
                  phy_tmp |= (MII_CR_AUTO_NEG_EN |
                            MII_CR_RESTART_AUTO_NEG);
                  e1000_write_phy_reg(&adapter->hw, PHY_CONTROL, phy_tmp);
            }
      }
      /* Restart process after EM_SMARTSPEED_MAX iterations */
      if(adapter->smartspeed++ == EM_SMARTSPEED_MAX)
            adapter->smartspeed = 0;
}


/*
 * Manage DMA'able memory.
 */
static void
em_dmamap_cb(void *arg, bus_dma_segment_t *segs, int nseg, int error)
{
      if (error)
            return;
      *(bus_addr_t *) arg = segs[0].ds_addr;
}

static int
em_dma_malloc(struct adapter *adapter, bus_size_t size,
        struct em_dma_alloc *dma, int mapflags)
{
      int error;

#if __FreeBSD_version >= 700000
      error = bus_dma_tag_create(bus_get_dma_tag(adapter->dev), /* parent */
#else
      error = bus_dma_tag_create(NULL,           /* parent */
#endif
                        EM_DBA_ALIGN, 0,  /* alignment, bounds */
                        BUS_SPACE_MAXADDR,      /* lowaddr */
                        BUS_SPACE_MAXADDR,      /* highaddr */
                        NULL, NULL,       /* filter, filterarg */
                        size,             /* maxsize */
                        1,                /* nsegments */
                        size,             /* maxsegsize */
                        0,                /* flags */
                        NULL,             /* lockfunc */
                        NULL,             /* lockarg */
                        &dma->dma_tag);
      if (error) {
            device_printf(adapter->dev,
                "%s: bus_dma_tag_create failed: %d\n",
                __func__, error);
            goto fail_0;
      }

      error = bus_dmamem_alloc(dma->dma_tag, (void**) &dma->dma_vaddr,
          BUS_DMA_NOWAIT, &dma->dma_map);
      if (error) {
            device_printf(adapter->dev,
                "%s: bus_dmamem_alloc(%ju) failed: %d\n",
                __func__, (uintmax_t)size, error);
            goto fail_2;
      }

      dma->dma_paddr = 0;
      error = bus_dmamap_load(dma->dma_tag, dma->dma_map, dma->dma_vaddr,
          size, em_dmamap_cb, &dma->dma_paddr, mapflags | BUS_DMA_NOWAIT);
      if (error || dma->dma_paddr == 0) {
            device_printf(adapter->dev,
                "%s: bus_dmamap_load failed: %d\n",
                __func__, error);
            goto fail_3;
      }

      return (0);

fail_3:
      bus_dmamap_unload(dma->dma_tag, dma->dma_map);
fail_2:
      bus_dmamem_free(dma->dma_tag, dma->dma_vaddr, dma->dma_map);
      bus_dma_tag_destroy(dma->dma_tag);
fail_0:
      dma->dma_map = NULL;
      dma->dma_tag = NULL;

      return (error);
}

static void
em_dma_free(struct adapter *adapter, struct em_dma_alloc *dma)
{
      if (dma->dma_tag == NULL)
            return;
      if (dma->dma_map != NULL) {
            bus_dmamap_sync(dma->dma_tag, dma->dma_map,
                BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
            bus_dmamap_unload(dma->dma_tag, dma->dma_map);
            bus_dmamem_free(dma->dma_tag, dma->dma_vaddr, dma->dma_map);
            dma->dma_map = NULL;
      }
      bus_dma_tag_destroy(dma->dma_tag);
      dma->dma_tag = NULL;
}


/*********************************************************************
 *
 *  Allocate memory for tx_buffer structures. The tx_buffer stores all
 *  the information needed to transmit a packet on the wire.
 *
 **********************************************************************/
static int
em_allocate_transmit_structures(struct adapter *adapter)
{
      device_t dev = adapter->dev;
      struct em_buffer *tx_buffer;
      int error;

      /*
       * Create DMA tags for tx descriptors
       */
#if __FreeBSD_version >= 700000
      if ((error = bus_dma_tag_create(bus_get_dma_tag(dev), /* parent */
#else
      if ((error = bus_dma_tag_create(NULL,            /* parent */
#endif
                        1, 0,             /* alignment, bounds */
                        BUS_SPACE_MAXADDR,      /* lowaddr */
                        BUS_SPACE_MAXADDR,      /* highaddr */
                        NULL, NULL,       /* filter, filterarg */
                        EM_TSO_SIZE,            /* maxsize */
                        EM_MAX_SCATTER,         /* nsegments */
                        EM_TSO_SEG_SIZE,  /* maxsegsize */
                        0,                /* flags */
                        NULL,       /* lockfunc */
                        NULL,       /* lockarg */
                        &adapter->txtag)) != 0) {
            device_printf(dev, "Unable to allocate TX DMA tag\n");
            goto fail;
      }

      adapter->tx_buffer_area = malloc(sizeof(struct em_buffer) *
          adapter->num_tx_desc, M_DEVBUF, M_NOWAIT | M_ZERO);
      if (adapter->tx_buffer_area == NULL) {
            device_printf(dev, "Unable to allocate tx_buffer memory\n");
            error = ENOMEM;
            goto fail;
      }

      /* Create the descriptor buffer dma maps */
      for (int i = 0; i < adapter->num_tx_desc; i++) {
            tx_buffer = &adapter->tx_buffer_area[i];
            error = bus_dmamap_create(adapter->txtag, 0, &tx_buffer->map);
            if (error != 0) {
                  device_printf(dev, "Unable to create TX DMA map\n");
                  goto fail;
            }
            tx_buffer->next_eop = -1;
      }

      return (0);
fail:
      em_free_transmit_structures(adapter);
      return (error);
}

/*********************************************************************
 *
 *  (Re)Initialize transmit structures.
 *
 **********************************************************************/
static void
em_setup_transmit_structures(struct adapter *adapter)
{
      struct em_buffer *tx_buffer;

      /* Clear the old ring contents */
      bzero(adapter->tx_desc_base,
          (sizeof(struct e1000_tx_desc)) * adapter->num_tx_desc);

      /* Free any existing TX buffers */
      for (int i = 0; i < adapter->num_tx_desc; i++, tx_buffer++) {
            tx_buffer = &adapter->tx_buffer_area[i];
            bus_dmamap_sync(adapter->txtag, tx_buffer->map,
                BUS_DMASYNC_POSTWRITE);
            bus_dmamap_unload(adapter->txtag, tx_buffer->map);
            m_freem(tx_buffer->m_head);
            tx_buffer->m_head = NULL;
            tx_buffer->next_eop = -1;
      }

      /* Reset state */
      adapter->next_avail_tx_desc = 0;
      adapter->next_tx_to_clean = 0;
      adapter->num_tx_desc_avail = adapter->num_tx_desc;

      bus_dmamap_sync(adapter->txdma.dma_tag, adapter->txdma.dma_map,
          BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);

      return;
}

/*********************************************************************
 *
 *  Enable transmit unit.
 *
 **********************************************************************/
static void
em_initialize_transmit_unit(struct adapter *adapter)
{
      uint32_t    tctl, tarc, tipg = 0;
      uint64_t    bus_addr;

       INIT_DEBUGOUT("em_initialize_transmit_unit: begin");
      /* Setup the Base and Length of the Tx Descriptor Ring */
      bus_addr = adapter->txdma.dma_paddr;
      E1000_WRITE_REG(&adapter->hw, E1000_TDLEN(0),
          adapter->num_tx_desc * sizeof(struct e1000_tx_desc));
      E1000_WRITE_REG(&adapter->hw, E1000_TDBAH(0),
          (uint32_t)(bus_addr >> 32));
      E1000_WRITE_REG(&adapter->hw, E1000_TDBAL(0),
          (uint32_t)bus_addr);
      /* Setup the HW Tx Head and Tail descriptor pointers */
      E1000_WRITE_REG(&adapter->hw, E1000_TDT(0), 0);
      E1000_WRITE_REG(&adapter->hw, E1000_TDH(0), 0);

      HW_DEBUGOUT2("Base = %x, Length = %x\n",
          E1000_READ_REG(&adapter->hw, E1000_TDBAL(0)),
          E1000_READ_REG(&adapter->hw, E1000_TDLEN(0)));

      /* Set the default values for the Tx Inter Packet Gap timer */
      switch (adapter->hw.mac.type) {
      case e1000_82542:
            tipg = DEFAULT_82542_TIPG_IPGT;
            tipg |= DEFAULT_82542_TIPG_IPGR1 << E1000_TIPG_IPGR1_SHIFT;
            tipg |= DEFAULT_82542_TIPG_IPGR2 << E1000_TIPG_IPGR2_SHIFT;
            break;
      case e1000_80003es2lan:
            tipg = DEFAULT_82543_TIPG_IPGR1;
            tipg |= DEFAULT_80003ES2LAN_TIPG_IPGR2 <<
                E1000_TIPG_IPGR2_SHIFT;
            break;
      default:
            if ((adapter->hw.phy.media_type == e1000_media_type_fiber) ||
                (adapter->hw.phy.media_type ==
                e1000_media_type_internal_serdes))
                  tipg = DEFAULT_82543_TIPG_IPGT_FIBER;
            else
                  tipg = DEFAULT_82543_TIPG_IPGT_COPPER;
            tipg |= DEFAULT_82543_TIPG_IPGR1 << E1000_TIPG_IPGR1_SHIFT;
            tipg |= DEFAULT_82543_TIPG_IPGR2 << E1000_TIPG_IPGR2_SHIFT;
      }

      E1000_WRITE_REG(&adapter->hw, E1000_TIPG, tipg);
      E1000_WRITE_REG(&adapter->hw, E1000_TIDV, adapter->tx_int_delay.value);
      if(adapter->hw.mac.type >= e1000_82540)
            E1000_WRITE_REG(&adapter->hw, E1000_TADV,
                adapter->tx_abs_int_delay.value);

      if ((adapter->hw.mac.type == e1000_82571) ||
          (adapter->hw.mac.type == e1000_82572)) {
            tarc = E1000_READ_REG(&adapter->hw, E1000_TARC(0));
            tarc |= SPEED_MODE_BIT;
            E1000_WRITE_REG(&adapter->hw, E1000_TARC(0), tarc);
      } else if (adapter->hw.mac.type == e1000_80003es2lan) {
            tarc = E1000_READ_REG(&adapter->hw, E1000_TARC(0));
            tarc |= 1;
            E1000_WRITE_REG(&adapter->hw, E1000_TARC(0), tarc);
            tarc = E1000_READ_REG(&adapter->hw, E1000_TARC(1));
            tarc |= 1;
            E1000_WRITE_REG(&adapter->hw, E1000_TARC(1), tarc);
      }

      /* Program the Transmit Control Register */
      tctl = E1000_READ_REG(&adapter->hw, E1000_TCTL);
      tctl &= ~E1000_TCTL_CT;
      tctl |= (E1000_TCTL_PSP | E1000_TCTL_RTLC | E1000_TCTL_EN |
               (E1000_COLLISION_THRESHOLD << E1000_CT_SHIFT));

      if (adapter->hw.mac.type >= e1000_82571)
            tctl |= E1000_TCTL_MULR;

      /* This write will effectively turn on the transmit unit. */
      E1000_WRITE_REG(&adapter->hw, E1000_TCTL, tctl);

      /* Setup Transmit Descriptor Base Settings */   
      adapter->txd_cmd = E1000_TXD_CMD_IFCS;

      if ((adapter->tx_int_delay.value > 0) &&
          (adapter->hw.mac.type != e1000_82575))
            adapter->txd_cmd |= E1000_TXD_CMD_IDE;

        /* Set the function pointer for the transmit routine */
        if (adapter->hw.mac.type >= e1000_82575)
                adapter->em_xmit = em_adv_encap;
        else
                adapter->em_xmit = em_encap;
}

/*********************************************************************
 *
 *  Free all transmit related data structures.
 *
 **********************************************************************/
static void
em_free_transmit_structures(struct adapter *adapter)
{
      struct em_buffer *tx_buffer;

      INIT_DEBUGOUT("free_transmit_structures: begin");

      if (adapter->tx_buffer_area != NULL) {
            for (int i = 0; i < adapter->num_tx_desc; i++) {
                  tx_buffer = &adapter->tx_buffer_area[i];
                  if (tx_buffer->m_head != NULL) {
                        bus_dmamap_sync(adapter->txtag, tx_buffer->map,
                            BUS_DMASYNC_POSTWRITE);
                        bus_dmamap_unload(adapter->txtag,
                            tx_buffer->map);
                        m_freem(tx_buffer->m_head);
                        tx_buffer->m_head = NULL;
                  } else if (tx_buffer->map != NULL)
                        bus_dmamap_unload(adapter->txtag,
                            tx_buffer->map);
                  if (tx_buffer->map != NULL) {
                        bus_dmamap_destroy(adapter->txtag,
                            tx_buffer->map);
                        tx_buffer->map = NULL;
                  }
            }
      }
      if (adapter->tx_buffer_area != NULL) {
            free(adapter->tx_buffer_area, M_DEVBUF);
            adapter->tx_buffer_area = NULL;
      }
      if (adapter->txtag != NULL) {
            bus_dma_tag_destroy(adapter->txtag);
            adapter->txtag = NULL;
      }
}

/*********************************************************************
 *
 *  The offload context needs to be set when we transfer the first
 *  packet of a particular protocol (TCP/UDP). This routine has been
 *  enhanced to deal with inserted VLAN headers, and IPV6 (not complete)
 *
 **********************************************************************/
static void
em_transmit_checksum_setup(struct adapter *adapter, struct mbuf *mp,
    uint32_t *txd_upper, uint32_t *txd_lower)
{
      struct e1000_context_desc *TXD;
      struct em_buffer *tx_buffer;
      struct ether_vlan_header *eh;
      struct ip *ip;
      struct ip6_hdr *ip6;
      struct tcp_hdr *th;
      int curr_txd, ehdrlen, hdr_len, ip_hlen;
      uint32_t cmd = 0;
      uint16_t etype;
      uint8_t ipproto;

      /* Setup checksum offload context. */
      curr_txd = adapter->next_avail_tx_desc;
      tx_buffer = &adapter->tx_buffer_area[curr_txd];
      TXD = (struct e1000_context_desc *) &adapter->tx_desc_base[curr_txd];

      *txd_lower = E1000_TXD_CMD_DEXT |   /* Extended descr type */
                 E1000_TXD_DTYP_D;        /* Data descr */

      /*
       * Determine where frame payload starts.
       * Jump over vlan headers if already present,
       * helpful for QinQ too.
       */
      eh = mtod(mp, struct ether_vlan_header *);
      if (eh->evl_encap_proto == htons(ETHERTYPE_VLAN)) {
            etype = ntohs(eh->evl_proto);
            ehdrlen = ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN;
      } else {
            etype = ntohs(eh->evl_encap_proto);
            ehdrlen = ETHER_HDR_LEN;
      }

      /*
       * We only support TCP/UDP for IPv4 and IPv6 for the moment.
       * TODO: Support SCTP too when it hits the tree.
       */
      switch (etype) {
      case ETHERTYPE_IP:
            ip = (struct ip *)(mp->m_data + ehdrlen);
            ip_hlen = ip->ip_hl << 2;

            /* Setup of IP header checksum. */
            if (mp->m_pkthdr.csum_flags & CSUM_IP) {
                  /*
                   * Start offset for header checksum calculation.
                   * End offset for header checksum calculation.
                   * Offset of place to put the checksum.
                   */
                  TXD->lower_setup.ip_fields.ipcss = ehdrlen;
                  TXD->lower_setup.ip_fields.ipcse =
                      htole16(ehdrlen + ip_hlen);
                  TXD->lower_setup.ip_fields.ipcso =
                      ehdrlen + offsetof(struct ip, ip_sum);
                  cmd |= E1000_TXD_CMD_IP;
                  *txd_upper |= E1000_TXD_POPTS_IXSM << 8;
            }

            if (mp->m_len < ehdrlen + ip_hlen)
                  return;     /* failure */

            hdr_len = ehdrlen + ip_hlen;
            ipproto = ip->ip_p;

            break;
      case ETHERTYPE_IPV6:
            ip6 = (struct ip6_hdr *)(mp->m_data + ehdrlen);
            ip_hlen = sizeof(struct ip6_hdr); /* XXX: No header stacking. */

            if (mp->m_len < ehdrlen + ip_hlen)
                  return;     /* failure */

            /* IPv6 doesn't have a header checksum. */

            hdr_len = ehdrlen + ip_hlen;
            ipproto = ip6->ip6_nxt;

            break;
      default:
            *txd_upper = 0;
            *txd_lower = 0;
            return;
      }

      switch (ipproto) {
      case IPPROTO_TCP:
            if (mp->m_pkthdr.csum_flags & CSUM_TCP) {
                  /*
                   * Start offset for payload checksum calculation.
                   * End offset for payload checksum calculation.
                   * Offset of place to put the checksum.
                   */
                  th = (struct tcp_hdr *)(mp->m_data + hdr_len);
                  TXD->upper_setup.tcp_fields.tucss = hdr_len;
                  TXD->upper_setup.tcp_fields.tucse = htole16(0);
                  TXD->upper_setup.tcp_fields.tucso =
                      hdr_len + offsetof(struct tcphdr, th_sum);
                  cmd |= E1000_TXD_CMD_TCP;
                  *txd_upper |= E1000_TXD_POPTS_TXSM << 8;
            }
            break;
      case IPPROTO_UDP:
            if (mp->m_pkthdr.csum_flags & CSUM_UDP) {
                  /*
                   * Start offset for header checksum calculation.
                   * End offset for header checksum calculation.
                   * Offset of place to put the checksum.
                   */
                  TXD->upper_setup.tcp_fields.tucss = hdr_len;
                  TXD->upper_setup.tcp_fields.tucse = htole16(0);
                  TXD->upper_setup.tcp_fields.tucso =
                      hdr_len + offsetof(struct udphdr, uh_sum);
                  *txd_upper |= E1000_TXD_POPTS_TXSM << 8;
            }
            break;
      default:
            break;
      }

      TXD->tcp_seg_setup.data = htole32(0);
      TXD->cmd_and_length =
          htole32(adapter->txd_cmd | E1000_TXD_CMD_DEXT | cmd);
      tx_buffer->m_head = NULL;
      tx_buffer->next_eop = -1;

      if (++curr_txd == adapter->num_tx_desc)
            curr_txd = 0;

      adapter->num_tx_desc_avail--;
      adapter->next_avail_tx_desc = curr_txd;
}


#if __FreeBSD_version >= 700000
/**********************************************************************
 *
 *  Setup work for hardware segmentation offload (TSO)
 *
 **********************************************************************/
static boolean_t
em_tso_setup(struct adapter *adapter, struct mbuf *mp, uint32_t *txd_upper,
   uint32_t *txd_lower)
{
      struct e1000_context_desc *TXD;
      struct em_buffer *tx_buffer;
      struct ether_vlan_header *eh;
      struct ip *ip;
      struct ip6_hdr *ip6;
      struct tcphdr *th;
      int curr_txd, ehdrlen, hdr_len, ip_hlen, isip6;
      uint16_t etype;

      /*
       * XXX: This is not really correct as the stack would not have
       * set up all checksums.
       * XXX: Return FALSE is not sufficient as we may have to return
       * in true failure cases as well.  Should do -1 (failure), 0 (no)
       * and 1 (success).
       */
      if (((mp->m_pkthdr.csum_flags & CSUM_TSO) == 0) ||
           (mp->m_pkthdr.len <= EM_TX_BUFFER_SIZE))
            return FALSE;

      /*
       * This function could/should be extended to support IP/IPv6
       * fragmentation as well.  But as they say, one step at a time.
       */

      /*
       * Determine where frame payload starts.
       * Jump over vlan headers if already present,
       * helpful for QinQ too.
       */
      eh = mtod(mp, struct ether_vlan_header *);
      if (eh->evl_encap_proto == htons(ETHERTYPE_VLAN)) {
            etype = ntohs(eh->evl_proto);
            ehdrlen = ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN;
      } else {
            etype = ntohs(eh->evl_encap_proto);
            ehdrlen = ETHER_HDR_LEN;
      }

      /* Ensure we have at least the IP+TCP header in the first mbuf. */
      if (mp->m_len < ehdrlen + sizeof(struct ip) + sizeof(struct tcphdr))
            return FALSE;     /* -1 */

      /*
       * We only support TCP for IPv4 and IPv6 (notyet) for the moment.
       * TODO: Support SCTP too when it hits the tree.
       */
      switch (etype) {
      case ETHERTYPE_IP:
            isip6 = 0;
            ip = (struct ip *)(mp->m_data + ehdrlen);
            if (ip->ip_p != IPPROTO_TCP)
                  return FALSE;     /* 0 */
            ip->ip_len = 0;
            ip->ip_sum = 0;
            ip_hlen = ip->ip_hl << 2;
            if (mp->m_len < ehdrlen + ip_hlen + sizeof(struct tcphdr))
                  return FALSE;     /* -1 */
            th = (struct tcphdr *)((caddr_t)ip + ip_hlen);
#if 1
            th->th_sum = in_pseudo(ip->ip_src.s_addr,
                ip->ip_dst.s_addr, htons(IPPROTO_TCP));
#else
            th->th_sum = mp->m_pkthdr.csum_data;
#endif
            break;
      case ETHERTYPE_IPV6:
            isip6 = 1;
            return FALSE;                 /* Not supported yet. */
            ip6 = (struct ip6_hdr *)(mp->m_data + ehdrlen);
            if (ip6->ip6_nxt != IPPROTO_TCP)
                  return FALSE;     /* 0 */
            ip6->ip6_plen = 0;
            ip_hlen = sizeof(struct ip6_hdr); /* XXX: no header stacking. */
            if (mp->m_len < ehdrlen + ip_hlen + sizeof(struct tcphdr))
                  return FALSE;     /* -1 */
            th = (struct tcphdr *)((caddr_t)ip6 + ip_hlen);
#if 0
            th->th_sum = in6_pseudo(ip6->ip6_src, ip->ip6_dst,
                htons(IPPROTO_TCP));      /* XXX: function notyet. */
#else
            th->th_sum = mp->m_pkthdr.csum_data;
#endif
            break;
      default:
            return FALSE;
      }
      hdr_len = ehdrlen + ip_hlen + (th->th_off << 2);

      *txd_lower = (E1000_TXD_CMD_DEXT |  /* Extended descr type */
                  E1000_TXD_DTYP_D |      /* Data descr type */
                  E1000_TXD_CMD_TSE);     /* Do TSE on this packet */

      /* IP and/or TCP header checksum calculation and insertion. */
      *txd_upper = ((isip6 ? 0 : E1000_TXD_POPTS_IXSM) |
                  E1000_TXD_POPTS_TXSM) << 8;

      curr_txd = adapter->next_avail_tx_desc;
      tx_buffer = &adapter->tx_buffer_area[curr_txd];
      TXD = (struct e1000_context_desc *) &adapter->tx_desc_base[curr_txd];

      /* IPv6 doesn't have a header checksum. */
      if (!isip6) {
            /*
             * Start offset for header checksum calculation.
             * End offset for header checksum calculation.
             * Offset of place put the checksum.
             */
            TXD->lower_setup.ip_fields.ipcss = ehdrlen;
            TXD->lower_setup.ip_fields.ipcse =
                htole16(ehdrlen + ip_hlen - 1);
            TXD->lower_setup.ip_fields.ipcso =
                ehdrlen + offsetof(struct ip, ip_sum);
      }
      /*
       * Start offset for payload checksum calculation.
       * End offset for payload checksum calculation.
       * Offset of place to put the checksum.
       */
      TXD->upper_setup.tcp_fields.tucss =
          ehdrlen + ip_hlen;
      TXD->upper_setup.tcp_fields.tucse = 0;
      TXD->upper_setup.tcp_fields.tucso =
          ehdrlen + ip_hlen + offsetof(struct tcphdr, th_sum);
      /*
       * Payload size per packet w/o any headers.
       * Length of all headers up to payload.
       */
      TXD->tcp_seg_setup.fields.mss = htole16(mp->m_pkthdr.tso_segsz);
      TXD->tcp_seg_setup.fields.hdr_len = hdr_len;

      TXD->cmd_and_length = htole32(adapter->txd_cmd |
                        E1000_TXD_CMD_DEXT |    /* Extended descr */
                        E1000_TXD_CMD_TSE |     /* TSE context */
                        (isip6 ? 0 : E1000_TXD_CMD_IP) | /* Do IP csum */
                        E1000_TXD_CMD_TCP |     /* Do TCP checksum */
                        (mp->m_pkthdr.len - (hdr_len))); /* Total len */

      tx_buffer->m_head = NULL;
      tx_buffer->next_eop = -1;

      if (++curr_txd == adapter->num_tx_desc)
            curr_txd = 0;

      adapter->num_tx_desc_avail--;
      adapter->next_avail_tx_desc = curr_txd;
      adapter->tx_tso = TRUE;

      return TRUE;
}


/**********************************************************************
 *
 *  Setup work for hardware segmentation offload (TSO) on
 *  adapters using advanced tx descriptors (82575)
 *
 **********************************************************************/
static boolean_t
em_tso_adv_setup(struct adapter *adapter, struct mbuf *mp, u32 *paylen)
{
      struct e1000_adv_tx_context_desc *TXD;
      struct em_buffer        *tx_buffer;
      u32 vlan_macip_lens = 0, type_tucmd_mlhl = 0;
      u32 mss_l4len_idx = 0;
      u16 vtag = 0;
      int ctxd, ehdrlen, hdrlen, ip_hlen, tcp_hlen;
      struct ether_vlan_header *eh;
      struct ip *ip;
      struct tcphdr *th;

      if (((mp->m_pkthdr.csum_flags & CSUM_TSO) == 0) ||
           (mp->m_pkthdr.len <= EM_TX_BUFFER_SIZE))
            return FALSE;

      /*
       * Determine where frame payload starts.
       * Jump over vlan headers if already present
       */
      eh = mtod(mp, struct ether_vlan_header *);
      if (eh->evl_encap_proto == htons(ETHERTYPE_VLAN))
            ehdrlen = ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN;
      else
            ehdrlen = ETHER_HDR_LEN;

      /* Ensure we have at least the IP+TCP header in the first mbuf. */
      if (mp->m_len < ehdrlen + sizeof(struct ip) + sizeof(struct tcphdr))
            return FALSE;

      /* Only supports IPV4 for now */
      ctxd = adapter->next_avail_tx_desc;
      tx_buffer = &adapter->tx_buffer_area[ctxd];
      TXD = (struct e1000_adv_tx_context_desc *) &adapter->tx_desc_base[ctxd];

      ip = (struct ip *)(mp->m_data + ehdrlen);
      if (ip->ip_p != IPPROTO_TCP)
                return FALSE;   /* 0 */
      ip->ip_len = 0;
      ip->ip_sum = 0;
      ip_hlen = ip->ip_hl << 2;
      th = (struct tcphdr *)((caddr_t)ip + ip_hlen);
      th->th_sum = in_pseudo(ip->ip_src.s_addr,
          ip->ip_dst.s_addr, htons(IPPROTO_TCP));
      tcp_hlen = th->th_off << 2;
      hdrlen = ehdrlen + ip_hlen + tcp_hlen;
      /* Calculate payload, this is used in the transmit desc in encap */
      *paylen = mp->m_pkthdr.len - hdrlen;

      /* VLAN MACLEN IPLEN */
      if (mp->m_flags & M_VLANTAG) {
            vtag = htole16(mp->m_pkthdr.ether_vtag);
            vlan_macip_lens |= (vtag << E1000_ADVTXD_VLAN_SHIFT);
      }

      vlan_macip_lens |= (ehdrlen << E1000_ADVTXD_MACLEN_SHIFT);
      vlan_macip_lens |= ip_hlen;
      TXD->vlan_macip_lens |= htole32(vlan_macip_lens);

      /* ADV DTYPE TUCMD */
      type_tucmd_mlhl |= E1000_ADVTXD_DCMD_DEXT | E1000_ADVTXD_DTYP_CTXT;
      type_tucmd_mlhl |= E1000_ADVTXD_TUCMD_L4T_TCP;
      type_tucmd_mlhl |= E1000_ADVTXD_TUCMD_IPV4;
      TXD->type_tucmd_mlhl |= htole32(type_tucmd_mlhl);

      /* MSS L4LEN IDX */
      mss_l4len_idx |= (mp->m_pkthdr.tso_segsz << E1000_ADVTXD_MSS_SHIFT);
      mss_l4len_idx |= (tcp_hlen << E1000_ADVTXD_L4LEN_SHIFT);
      TXD->mss_l4len_idx = htole32(mss_l4len_idx);

      TXD->seqnum_seed = htole32(0);
      tx_buffer->m_head = NULL;
      tx_buffer->next_eop = -1;

      if (++ctxd == adapter->num_tx_desc)
            ctxd = 0;

      adapter->num_tx_desc_avail--;
      adapter->next_avail_tx_desc = ctxd;
      return TRUE;
}

#endif /* FreeBSD_version >= 700000 */

/*********************************************************************
 *
 *  Advanced Context Descriptor setup for VLAN or CSUM
 *
 **********************************************************************/

static boolean_t
em_tx_adv_ctx_setup(struct adapter *adapter, struct mbuf *mp)
{
      struct e1000_adv_tx_context_desc *TXD;
      struct em_buffer        *tx_buffer;
      uint32_t vlan_macip_lens = 0, type_tucmd_mlhl = 0;
      struct ether_vlan_header *eh;
      struct ip *ip;
      struct ip6_hdr *ip6;
      int  ehdrlen, ip_hlen = 0;
      u16   etype;
      u8    ipproto = 0;
      bool  offload = TRUE;
#if __FreeBSD_version < 700000
      struct m_tag            *mtag;
#else
      u16 vtag = 0;
#endif

      int ctxd = adapter->next_avail_tx_desc;
      tx_buffer = &adapter->tx_buffer_area[ctxd];
      TXD = (struct e1000_adv_tx_context_desc *) &adapter->tx_desc_base[ctxd];

      if ((mp->m_pkthdr.csum_flags & CSUM_OFFLOAD) == 0)
            offload = FALSE; /* Only here to handle VLANs */
      /*
      ** In advanced descriptors the vlan tag must 
      ** be placed into the descriptor itself.
      */
#if __FreeBSD_version < 700000
        mtag = VLAN_OUTPUT_TAG(ifp, mp);
        if (mtag != NULL) {
            vlan_macip_lens |=
                    htole16(VLAN_TAG_VALUE(mtag)) << E1000_ADVTXD_VLAN_SHIFT;
      } else if (offload == FALSE)
            return FALSE;     /* No CTX needed */
#else
      if (mp->m_flags & M_VLANTAG) {
            vtag = htole16(mp->m_pkthdr.ether_vtag);
            vlan_macip_lens |= (vtag << E1000_ADVTXD_VLAN_SHIFT);
      } else if (offload == FALSE)
            return FALSE;
#endif
      /*
       * Determine where frame payload starts.
       * Jump over vlan headers if already present,
       * helpful for QinQ too.
       */
      eh = mtod(mp, struct ether_vlan_header *);
      if (eh->evl_encap_proto == htons(ETHERTYPE_VLAN)) {
            etype = ntohs(eh->evl_proto);
            ehdrlen = ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN;
      } else {
            etype = ntohs(eh->evl_encap_proto);
            ehdrlen = ETHER_HDR_LEN;
      }

      /* Set the ether header length */
      vlan_macip_lens |= ehdrlen << E1000_ADVTXD_MACLEN_SHIFT;

      switch (etype) {
            case ETHERTYPE_IP:
                  ip = (struct ip *)(mp->m_data + ehdrlen);
                  ip_hlen = ip->ip_hl << 2;
                  if (mp->m_len < ehdrlen + ip_hlen) {
                        offload = FALSE;
                        break;
                  }
                  ipproto = ip->ip_p;
                  type_tucmd_mlhl |= E1000_ADVTXD_TUCMD_IPV4;
                  break;
            case ETHERTYPE_IPV6:
                  ip6 = (struct ip6_hdr *)(mp->m_data + ehdrlen);
                  ip_hlen = sizeof(struct ip6_hdr);
                  if (mp->m_len < ehdrlen + ip_hlen)
                        return FALSE; /* failure */
                  ipproto = ip6->ip6_nxt;
                  type_tucmd_mlhl |= E1000_ADVTXD_TUCMD_IPV6;
                  break;
            default:
                  offload = FALSE;
                  break;
      }

      vlan_macip_lens |= ip_hlen;
      type_tucmd_mlhl |= E1000_ADVTXD_DCMD_DEXT | E1000_ADVTXD_DTYP_CTXT;

      switch (ipproto) {
            case IPPROTO_TCP:
                  if (mp->m_pkthdr.csum_flags & CSUM_TCP)
                        type_tucmd_mlhl |= E1000_ADVTXD_TUCMD_L4T_TCP;
                  break;
            case IPPROTO_UDP:
                  if (mp->m_pkthdr.csum_flags & CSUM_UDP)
                        type_tucmd_mlhl |= E1000_ADVTXD_TUCMD_L4T_UDP;
                  break;
            default:
                  offload = FALSE;
                  break;
      }

      /* Now copy bits into descriptor */
      TXD->vlan_macip_lens |= htole32(vlan_macip_lens);
      TXD->type_tucmd_mlhl |= htole32(type_tucmd_mlhl);
      TXD->seqnum_seed = htole32(0);
      TXD->mss_l4len_idx = htole32(0);

      tx_buffer->m_head = NULL;
      tx_buffer->next_eop = -1;

      /* We've consumed the first desc, adjust counters */
      if (++ctxd == adapter->num_tx_desc)
            ctxd = 0;
      adapter->next_avail_tx_desc = ctxd;
      --adapter->num_tx_desc_avail;

        return (offload);
}


/**********************************************************************
 *
 *  Examine each tx_buffer in the used queue. If the hardware is done
 *  processing the packet then free associated resources. The
 *  tx_buffer is put back on the free queue.
 *
 **********************************************************************/
static void
em_txeof(struct adapter *adapter)
{
        int first, last, done, num_avail;
        struct em_buffer *tx_buffer;
        struct e1000_tx_desc   *tx_desc, *eop_desc;
      struct ifnet   *ifp = adapter->ifp;

      EM_TX_LOCK_ASSERT(adapter);

        if (adapter->num_tx_desc_avail == adapter->num_tx_desc)
                return;

        num_avail = adapter->num_tx_desc_avail;
        first = adapter->next_tx_to_clean;
        tx_desc = &adapter->tx_desc_base[first];
        tx_buffer = &adapter->tx_buffer_area[first];
      last = tx_buffer->next_eop;
        eop_desc = &adapter->tx_desc_base[last];

      /*
       * What this does is get the index of the
       * first descriptor AFTER the EOP of the 
       * first packet, that way we can do the
       * simple comparison on the inner while loop.
       */
      if (++last == adapter->num_tx_desc)
            last = 0;
      done = last;

        bus_dmamap_sync(adapter->txdma.dma_tag, adapter->txdma.dma_map,
            BUS_DMASYNC_POSTREAD);

        while (eop_desc->upper.fields.status & E1000_TXD_STAT_DD) {
            /* We clean the range of the packet */
            while (first != done) {
                  tx_desc->upper.data = 0;
                  tx_desc->lower.data = 0;
                  tx_desc->buffer_addr = 0;
                  num_avail++;

                  if (tx_buffer->m_head) {
                        ifp->if_opackets++;
                        bus_dmamap_sync(adapter->txtag,
                            tx_buffer->map,
                            BUS_DMASYNC_POSTWRITE);
                        bus_dmamap_unload(adapter->txtag,
                            tx_buffer->map);

                              m_freem(tx_buffer->m_head);
                              tx_buffer->m_head = NULL;
                  }
                  tx_buffer->next_eop = -1;

                      if (++first == adapter->num_tx_desc)
                        first = 0;

                      tx_buffer = &adapter->tx_buffer_area[first];
                  tx_desc = &adapter->tx_desc_base[first];
            }
            /* See if we can continue to the next packet */
            last = tx_buffer->next_eop;
            if (last != -1) {
                  eop_desc = &adapter->tx_desc_base[last];
                  /* Get new done point */
                  if (++last == adapter->num_tx_desc) last = 0;
                  done = last;
            } else
                  break;
        }
        bus_dmamap_sync(adapter->txdma.dma_tag, adapter->txdma.dma_map,
            BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);

        adapter->next_tx_to_clean = first;

        /*
         * If we have enough room, clear IFF_DRV_OACTIVE to tell the stack
         * that it is OK to send packets.
         * If there are no pending descriptors, clear the timeout. Otherwise,
         * if some descriptors have been freed, restart the timeout.
         */
        if (num_avail > EM_TX_CLEANUP_THRESHOLD) {                
                ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
            /* All clean, turn off the timer */
                if (num_avail == adapter->num_tx_desc)
                  adapter->watchdog_timer = 0;
            /* Some cleaned, reset the timer */
                else if (num_avail != adapter->num_tx_desc_avail)
                  adapter->watchdog_timer = EM_TX_TIMEOUT;
        }
        adapter->num_tx_desc_avail = num_avail;
        return;
}

/*********************************************************************
 *
 *  When Link is lost sometimes there is work still in the TX ring
 *  which will result in a watchdog, rather than allow that do an
 *  attempted cleanup and then reinit here. Note that this has been
 *  seens mostly with fiber adapters.
 *
 **********************************************************************/
static void
em_tx_purge(struct adapter *adapter)
{
      if ((!adapter->link_active) && (adapter->watchdog_timer)) {
            EM_TX_LOCK(adapter);
            em_txeof(adapter);
            EM_TX_UNLOCK(adapter);
            if (adapter->watchdog_timer) { /* Still not clean? */
                  adapter->watchdog_timer = 0;
                  em_init_locked(adapter);
            }
      }
}

/*********************************************************************
 *
 *  Get a buffer from system mbuf buffer pool.
 *
 **********************************************************************/
static int
em_get_buf(struct adapter *adapter, int i)
{
      struct mbuf       *m;
      bus_dma_segment_t segs[1];
      bus_dmamap_t            map;
      struct em_buffer  *rx_buffer;
      int               error, nsegs;

      m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
      if (m == NULL) {
            adapter->mbuf_cluster_failed++;
            return (ENOBUFS);
      }
      m->m_len = m->m_pkthdr.len = MCLBYTES;

      if (adapter->max_frame_size <= (MCLBYTES - ETHER_ALIGN))
            m_adj(m, ETHER_ALIGN);

      /*
       * Using memory from the mbuf cluster pool, invoke the
       * bus_dma machinery to arrange the memory mapping.
       */
      error = bus_dmamap_load_mbuf_sg(adapter->rxtag,
          adapter->rx_sparemap, m, segs, &nsegs, BUS_DMA_NOWAIT);
      if (error != 0) {
            m_free(m);
            return (error);
      }

      /* If nsegs is wrong then the stack is corrupt. */
      KASSERT(nsegs == 1, ("Too many segments returned!"));

      rx_buffer = &adapter->rx_buffer_area[i];
      if (rx_buffer->m_head != NULL)
            bus_dmamap_unload(adapter->rxtag, rx_buffer->map);

      map = rx_buffer->map;
      rx_buffer->map = adapter->rx_sparemap;
      adapter->rx_sparemap = map;
      bus_dmamap_sync(adapter->rxtag, rx_buffer->map, BUS_DMASYNC_PREREAD);
      rx_buffer->m_head = m;

      adapter->rx_desc_base[i].buffer_addr = htole64(segs[0].ds_addr);
      return (0);
}

/*********************************************************************
 *
 *  Allocate memory for rx_buffer structures. Since we use one
 *  rx_buffer per received packet, the maximum number of rx_buffer's
 *  that we'll need is equal to the number of receive descriptors
 *  that we've allocated.
 *
 **********************************************************************/
static int
em_allocate_receive_structures(struct adapter *adapter)
{
      device_t dev = adapter->dev;
      struct em_buffer *rx_buffer;
      int i, error;

      adapter->rx_buffer_area = malloc(sizeof(struct em_buffer) *
          adapter->num_rx_desc, M_DEVBUF, M_NOWAIT | M_ZERO);
      if (adapter->rx_buffer_area == NULL) {
            device_printf(dev, "Unable to allocate rx_buffer memory\n");
            return (ENOMEM);
      }

#if __FreeBSD_version >= 700000
      error = bus_dma_tag_create(bus_get_dma_tag(dev), /* parent */
#else
      error = bus_dma_tag_create(NULL,           /* parent */
#endif
                        1, 0,             /* alignment, bounds */
                        BUS_SPACE_MAXADDR,      /* lowaddr */
                        BUS_SPACE_MAXADDR,      /* highaddr */
                        NULL, NULL,       /* filter, filterarg */
                        MCLBYTES,         /* maxsize */
                        1,                /* nsegments */
                        MCLBYTES,         /* maxsegsize */
                        0,                /* flags */
                        NULL,             /* lockfunc */
                        NULL,             /* lockarg */
                        &adapter->rxtag);
      if (error) {
            device_printf(dev, "%s: bus_dma_tag_create failed %d\n",
                __func__, error);
            goto fail;
      }

      /* Create the spare map (used by getbuf) */
      error = bus_dmamap_create(adapter->rxtag, BUS_DMA_NOWAIT,
           &adapter->rx_sparemap);
      if (error) {
            device_printf(dev, "%s: bus_dmamap_create failed: %d\n",
                __func__, error);
            goto fail;
      }

      rx_buffer = adapter->rx_buffer_area;
      for (i = 0; i < adapter->num_rx_desc; i++, rx_buffer++) {
            error = bus_dmamap_create(adapter->rxtag, BUS_DMA_NOWAIT,
                &rx_buffer->map);
            if (error) {
                  device_printf(dev, "%s: bus_dmamap_create failed: %d\n",
                      __func__, error);
                  goto fail;
            }
      }

      return (0);

fail:
      em_free_receive_structures(adapter);
      return (error);
}

/*********************************************************************
 *
 *  (Re)initialize receive structures.
 *
 **********************************************************************/
static int
em_setup_receive_structures(struct adapter *adapter)
{
      struct em_buffer *rx_buffer;
      int i, error;

      /* Reset descriptor ring */
      bzero(adapter->rx_desc_base,
          (sizeof(struct e1000_rx_desc)) * adapter->num_rx_desc);

      /* Free current RX buffers. */
      rx_buffer = adapter->rx_buffer_area;
      for (i = 0; i < adapter->num_rx_desc; i++, rx_buffer++) {
            if (rx_buffer->m_head != NULL) {
                  bus_dmamap_sync(adapter->rxtag, rx_buffer->map,
                      BUS_DMASYNC_POSTREAD);
                  bus_dmamap_unload(adapter->rxtag, rx_buffer->map);
                  m_freem(rx_buffer->m_head);
                  rx_buffer->m_head = NULL;
            }
        }

      /* Allocate new ones. */
      for (i = 0; i < adapter->num_rx_desc; i++) {
            error = em_get_buf(adapter, i);
            if (error)
                        return (error);
      }

      /* Setup our descriptor pointers */
      adapter->next_rx_desc_to_check = 0;
      bus_dmamap_sync(adapter->rxdma.dma_tag, adapter->rxdma.dma_map,
          BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);

      return (0);
}

/*********************************************************************
 *
 *  Enable receive unit.
 *
 **********************************************************************/
static void
em_initialize_receive_unit(struct adapter *adapter)
{
      struct ifnet      *ifp = adapter->ifp;
      uint64_t    bus_addr;
      uint32_t    reg_rctl;
      uint32_t    reg_rxcsum;

      INIT_DEBUGOUT("em_initialize_receive_unit: begin");

      /*
       * Make sure receives are disabled while setting
       * up the descriptor ring
       */
      reg_rctl = E1000_READ_REG(&adapter->hw, E1000_RCTL);
      E1000_WRITE_REG(&adapter->hw, E1000_RCTL, reg_rctl & ~E1000_RCTL_EN);

      if(adapter->hw.mac.type >= e1000_82540) {
            E1000_WRITE_REG(&adapter->hw, E1000_RADV,
                adapter->rx_abs_int_delay.value);
            /*
             * Set the interrupt throttling rate. Value is calculated
             * as DEFAULT_ITR = 1/(MAX_INTS_PER_SEC * 256ns)
             */
#define MAX_INTS_PER_SEC      8000
#define DEFAULT_ITR          1000000000/(MAX_INTS_PER_SEC * 256)
            E1000_WRITE_REG(&adapter->hw, E1000_ITR, DEFAULT_ITR);
      }

      /* Setup the Base and Length of the Rx Descriptor Ring */
      bus_addr = adapter->rxdma.dma_paddr;
      E1000_WRITE_REG(&adapter->hw, E1000_RDLEN(0),
          adapter->num_rx_desc * sizeof(struct e1000_rx_desc));
      E1000_WRITE_REG(&adapter->hw, E1000_RDBAH(0),
          (uint32_t)(bus_addr >> 32));
      E1000_WRITE_REG(&adapter->hw, E1000_RDBAL(0),
          (uint32_t)bus_addr);

      /* Setup the Receive Control Register */
      reg_rctl &= ~(3 << E1000_RCTL_MO_SHIFT);
      reg_rctl |= E1000_RCTL_EN | E1000_RCTL_BAM | E1000_RCTL_LBM_NO |
               E1000_RCTL_RDMTS_HALF |
               (adapter->hw.mac.mc_filter_type << E1000_RCTL_MO_SHIFT);

      /* Make sure VLAN Filters are off */
      reg_rctl &= ~E1000_RCTL_VFE;

      if (e1000_tbi_sbp_enabled_82543(&adapter->hw))
            reg_rctl |= E1000_RCTL_SBP;
      else
            reg_rctl &= ~E1000_RCTL_SBP;

      switch (adapter->rx_buffer_len) {
      default:
      case 2048:
            reg_rctl |= E1000_RCTL_SZ_2048;
            break;
      case 4096:
            reg_rctl |= E1000_RCTL_SZ_4096 |
                E1000_RCTL_BSEX | E1000_RCTL_LPE;
            break;
      case 8192:
            reg_rctl |= E1000_RCTL_SZ_8192 |
                E1000_RCTL_BSEX | E1000_RCTL_LPE;
            break;
      case 16384:
            reg_rctl |= E1000_RCTL_SZ_16384 |
                E1000_RCTL_BSEX | E1000_RCTL_LPE;
            break;
      }

      if (ifp->if_mtu > ETHERMTU)
            reg_rctl |= E1000_RCTL_LPE;
      else
            reg_rctl &= ~E1000_RCTL_LPE;

      /* Enable 82543 Receive Checksum Offload for TCP and UDP */
      if ((adapter->hw.mac.type >= e1000_82543) &&
          (ifp->if_capenable & IFCAP_RXCSUM)) {
            reg_rxcsum = E1000_READ_REG(&adapter->hw, E1000_RXCSUM);
            reg_rxcsum |= (E1000_RXCSUM_IPOFL | E1000_RXCSUM_TUOFL);
            E1000_WRITE_REG(&adapter->hw, E1000_RXCSUM, reg_rxcsum);
      }

      /*
      ** XXX TEMPORARY WORKAROUND: on some systems with 82573
      ** long latencies are observed, like Lenovo X60. This
      ** change eliminates the problem, but since having positive
      ** values in RDTR is a known source of problems on other
      ** platforms another solution is being sought.
      */
      if (adapter->hw.mac.type == e1000_82573)
            E1000_WRITE_REG(&adapter->hw, E1000_RDTR, 0x20);

      /* Enable Receives */
      E1000_WRITE_REG(&adapter->hw, E1000_RCTL, reg_rctl);

      /*
       * Setup the HW Rx Head and
       * Tail Descriptor Pointers
       */
      E1000_WRITE_REG(&adapter->hw, E1000_RDH(0), 0);
      E1000_WRITE_REG(&adapter->hw, E1000_RDT(0), adapter->num_rx_desc - 1);

      return;
}

/*********************************************************************
 *
 *  Free receive related data structures.
 *
 **********************************************************************/
static void
em_free_receive_structures(struct adapter *adapter)
{
      struct em_buffer *rx_buffer;
      int i;

      INIT_DEBUGOUT("free_receive_structures: begin");

      if (adapter->rx_sparemap) {
            bus_dmamap_destroy(adapter->rxtag, adapter->rx_sparemap);
            adapter->rx_sparemap = NULL;
      }

      /* Cleanup any existing buffers */
      if (adapter->rx_buffer_area != NULL) {
            rx_buffer = adapter->rx_buffer_area;
            for (i = 0; i < adapter->num_rx_desc; i++, rx_buffer++) {
                  if (rx_buffer->m_head != NULL) {
                        bus_dmamap_sync(adapter->rxtag, rx_buffer->map,
                            BUS_DMASYNC_POSTREAD);
                        bus_dmamap_unload(adapter->rxtag,
                            rx_buffer->map);
                        m_freem(rx_buffer->m_head);
                        rx_buffer->m_head = NULL;
                  } else if (rx_buffer->map != NULL)
                        bus_dmamap_unload(adapter->rxtag,
                            rx_buffer->map);
                  if (rx_buffer->map != NULL) {
                        bus_dmamap_destroy(adapter->rxtag,
                            rx_buffer->map);
                        rx_buffer->map = NULL;
                  }
            }
      }

      if (adapter->rx_buffer_area != NULL) {
            free(adapter->rx_buffer_area, M_DEVBUF);
            adapter->rx_buffer_area = NULL;
      }

      if (adapter->rxtag != NULL) {
            bus_dma_tag_destroy(adapter->rxtag);
            adapter->rxtag = NULL;
      }
}

/*********************************************************************
 *
 *  This routine executes in interrupt context. It replenishes
 *  the mbufs in the descriptor and sends data which has been
 *  dma'ed into host memory to upper layer.
 *
 *  We loop at most count times if count is > 0, or until done if
 *  count < 0.
 *
 *********************************************************************/
static int
em_rxeof(struct adapter *adapter, int count)
{
      struct ifnet      *ifp;
      struct mbuf *mp;
      uint8_t           accept_frame = 0;
      uint8_t           eop = 0;
      uint16_t    len, desc_len, prev_len_adj;
      int         i;

      /* Pointer to the receive descriptor being examined. */
      struct e1000_rx_desc   *current_desc;
      uint8_t           status;

      ifp = adapter->ifp;
      i = adapter->next_rx_desc_to_check;
      current_desc = &adapter->rx_desc_base[i];
      bus_dmamap_sync(adapter->rxdma.dma_tag, adapter->rxdma.dma_map,
          BUS_DMASYNC_POSTREAD);

      if (!((current_desc->status) & E1000_RXD_STAT_DD))
            return (0);

      while ((current_desc->status & E1000_RXD_STAT_DD) &&
          (count != 0) &&
          (ifp->if_drv_flags & IFF_DRV_RUNNING)) {
            struct mbuf *m = NULL;

            mp = adapter->rx_buffer_area[i].m_head;
            /*
             * Can't defer bus_dmamap_sync(9) because TBI_ACCEPT
             * needs to access the last received byte in the mbuf.
             */
            bus_dmamap_sync(adapter->rxtag, adapter->rx_buffer_area[i].map,
                BUS_DMASYNC_POSTREAD);

            accept_frame = 1;
            prev_len_adj = 0;
            desc_len = le16toh(current_desc->length);
            status = current_desc->status;
            if (status & E1000_RXD_STAT_EOP) {
                  count--;
                  eop = 1;
                  if (desc_len < ETHER_CRC_LEN) {
                        len = 0;
                        prev_len_adj = ETHER_CRC_LEN - desc_len;
                  } else
                        len = desc_len - ETHER_CRC_LEN;
            } else {
                  eop = 0;
                  len = desc_len;
            }

            if (current_desc->errors & E1000_RXD_ERR_FRAME_ERR_MASK) {
                  uint8_t           last_byte;
                  uint32_t    pkt_len = desc_len;

                  if (adapter->fmp != NULL)
                        pkt_len += adapter->fmp->m_pkthdr.len;

                  last_byte = *(mtod(mp, caddr_t) + desc_len - 1);                  
                  if (TBI_ACCEPT(&adapter->hw, status,
                      current_desc->errors, pkt_len, last_byte,
                      adapter->min_frame_size, adapter->max_frame_size)) {
                        e1000_tbi_adjust_stats_82543(&adapter->hw,
                            &adapter->stats, pkt_len,
                            adapter->hw.mac.addr,
                            adapter->max_frame_size);
                        if (len > 0)
                              len--;
                  } else
                        accept_frame = 0;
            }

            if (accept_frame) {
                  if (em_get_buf(adapter, i) != 0) {
                        ifp->if_iqdrops++;
                        goto discard;
                  }

                  /* Assign correct length to the current fragment */
                  mp->m_len = len;

                  if (adapter->fmp == NULL) {
                        mp->m_pkthdr.len = len;
                        adapter->fmp = mp; /* Store the first mbuf */
                        adapter->lmp = mp;
                  } else {
                        /* Chain mbuf's together */
                        mp->m_flags &= ~M_PKTHDR;
                        /*
                         * Adjust length of previous mbuf in chain if
                         * we received less than 4 bytes in the last
                         * descriptor.
                         */
                        if (prev_len_adj > 0) {
                              adapter->lmp->m_len -= prev_len_adj;
                              adapter->fmp->m_pkthdr.len -=
                                  prev_len_adj;
                        }
                        adapter->lmp->m_next = mp;
                        adapter->lmp = adapter->lmp->m_next;
                        adapter->fmp->m_pkthdr.len += len;
                  }

                  if (eop) {
                        adapter->fmp->m_pkthdr.rcvif = ifp;
                        ifp->if_ipackets++;
                        em_receive_checksum(adapter, current_desc,
                            adapter->fmp);
#ifndef __NO_STRICT_ALIGNMENT
                        if (adapter->max_frame_size >
                            (MCLBYTES - ETHER_ALIGN) &&
                            em_fixup_rx(adapter) != 0)
                              goto skip;
#endif
                        if (status & E1000_RXD_STAT_VP) {
#if __FreeBSD_version < 700000
                              VLAN_INPUT_TAG_NEW(ifp, adapter->fmp,
                                  (le16toh(current_desc->special) &
                                  E1000_RXD_SPC_VLAN_MASK));
#else
                              adapter->fmp->m_pkthdr.ether_vtag =
                                  (le16toh(current_desc->special) &
                                  E1000_RXD_SPC_VLAN_MASK);
                              adapter->fmp->m_flags |= M_VLANTAG;
#endif
                        }
#ifndef __NO_STRICT_ALIGNMENT
skip:
#endif
                        m = adapter->fmp;
                        adapter->fmp = NULL;
                        adapter->lmp = NULL;
                  }
            } else {
                  ifp->if_ierrors++;
discard:
                  /* Reuse loaded DMA map and just update mbuf chain */
                  mp = adapter->rx_buffer_area[i].m_head;
                  mp->m_len = mp->m_pkthdr.len = MCLBYTES;
                  mp->m_data = mp->m_ext.ext_buf;
                  mp->m_next = NULL;
                  if (adapter->max_frame_size <=
                      (MCLBYTES - ETHER_ALIGN))
                        m_adj(mp, ETHER_ALIGN);
                  if (adapter->fmp != NULL) {
                        m_freem(adapter->fmp);
                        adapter->fmp = NULL;
                        adapter->lmp = NULL;
                  }
                  m = NULL;
            }

            /* Zero out the receive descriptors status. */
            current_desc->status = 0;
            bus_dmamap_sync(adapter->rxdma.dma_tag, adapter->rxdma.dma_map,
                BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);

            /* Advance our pointers to the next descriptor. */
            if (++i == adapter->num_rx_desc)
                  i = 0;
            if (m != NULL) {
                  adapter->next_rx_desc_to_check = i;
#ifndef EM_FAST_IRQ
                  EM_CORE_UNLOCK(adapter);
                  (*ifp->if_input)(ifp, m);
                  EM_CORE_LOCK(adapter);
#else
                  /* Already running unlocked */
                  (*ifp->if_input)(ifp, m);
#endif
                  i = adapter->next_rx_desc_to_check;
            }
            current_desc = &adapter->rx_desc_base[i];
      }
      adapter->next_rx_desc_to_check = i;

      /* Advance the E1000's Receive Queue #0  "Tail Pointer". */
      if (--i < 0)
            i = adapter->num_rx_desc - 1;
      E1000_WRITE_REG(&adapter->hw, E1000_RDT(0), i);
      if (!((current_desc->status) & E1000_RXD_STAT_DD))
            return (0);

      return (1);
}

#ifndef __NO_STRICT_ALIGNMENT
/*
 * When jumbo frames are enabled we should realign entire payload on
 * architecures with strict alignment. This is serious design mistake of 8254x
 * as it nullifies DMA operations. 8254x just allows RX buffer size to be
 * 2048/4096/8192/16384. What we really want is 2048 - ETHER_ALIGN to align its
 * payload. On architecures without strict alignment restrictions 8254x still
 * performs unaligned memory access which would reduce the performance too.
 * To avoid copying over an entire frame to align, we allocate a new mbuf and
 * copy ethernet header to the new mbuf. The new mbuf is prepended into the
 * existing mbuf chain.
 *
 * Be aware, best performance of the 8254x is achived only when jumbo frame is
 * not used at all on architectures with strict alignment.
 */
static int
em_fixup_rx(struct adapter *adapter)
{
      struct mbuf *m, *n;
      int error;

      error = 0;
      m = adapter->fmp;
      if (m->m_len <= (MCLBYTES - ETHER_HDR_LEN)) {
            bcopy(m->m_data, m->m_data + ETHER_HDR_LEN, m->m_len);
            m->m_data += ETHER_HDR_LEN;
      } else {
            MGETHDR(n, M_DONTWAIT, MT_DATA);
            if (n != NULL) {
                  bcopy(m->m_data, n->m_data, ETHER_HDR_LEN);
                  m->m_data += ETHER_HDR_LEN;
                  m->m_len -= ETHER_HDR_LEN;
                  n->m_len = ETHER_HDR_LEN;
                  M_MOVE_PKTHDR(n, m);
                  n->m_next = m;
                  adapter->fmp = n;
            } else {
                  adapter->dropped_pkts++;
                  m_freem(adapter->fmp);
                  adapter->fmp = NULL;
                  error = ENOMEM;
            }
      }

      return (error);
}
#endif

/*********************************************************************
 *
 *  Verify that the hardware indicated that the checksum is valid.
 *  Inform the stack about the status of checksum so that stack
 *  doesn't spend time verifying the checksum.
 *
 *********************************************************************/
static void
em_receive_checksum(struct adapter *adapter,
          struct e1000_rx_desc *rx_desc, struct mbuf *mp)
{
      /* 82543 or newer only */
      if ((adapter->hw.mac.type < e1000_82543) ||
          /* Ignore Checksum bit is set */
          (rx_desc->status & E1000_RXD_STAT_IXSM)) {
            mp->m_pkthdr.csum_flags = 0;
            return;
      }

      if (rx_desc->status & E1000_RXD_STAT_IPCS) {
            /* Did it pass? */
            if (!(rx_desc->errors & E1000_RXD_ERR_IPE)) {
                  /* IP Checksum Good */
                  mp->m_pkthdr.csum_flags = CSUM_IP_CHECKED;
                  mp->m_pkthdr.csum_flags |= CSUM_IP_VALID;

            } else {
                  mp->m_pkthdr.csum_flags = 0;
            }
      }

      if (rx_desc->status & E1000_RXD_STAT_TCPCS) {
            /* Did it pass? */
            if (!(rx_desc->errors & E1000_RXD_ERR_TCPE)) {
                  mp->m_pkthdr.csum_flags |=
                  (CSUM_DATA_VALID | CSUM_PSEUDO_HDR);
                  mp->m_pkthdr.csum_data = htons(0xffff);
            }
      }
}

/*
 * This turns on the hardware offload of the VLAN
 * tag insertion and strip
 */
static void
em_enable_hw_vlans(struct adapter *adapter)
{
      uint32_t ctrl;

      ctrl = E1000_READ_REG(&adapter->hw, E1000_CTRL);
      ctrl |= E1000_CTRL_VME;
      E1000_WRITE_REG(&adapter->hw, E1000_CTRL, ctrl);
}

static void
em_enable_intr(struct adapter *adapter)
{
      E1000_WRITE_REG(&adapter->hw, E1000_IMS,
          (IMS_ENABLE_MASK));
}

static void
em_disable_intr(struct adapter *adapter)
{
      E1000_WRITE_REG(&adapter->hw, E1000_IMC, 0xffffffff);
}

/*
 * Bit of a misnomer, what this really means is
 * to enable OS management of the system... aka
 * to disable special hardware management features 
 */
static void
em_init_manageability(struct adapter *adapter)
{
      /* A shared code workaround */
#define E1000_82542_MANC2H E1000_MANC2H
      if (adapter->has_manage) {
            int manc2h = E1000_READ_REG(&adapter->hw, E1000_MANC2H);
            int manc = E1000_READ_REG(&adapter->hw, E1000_MANC);

            /* disable hardware interception of ARP */
            manc &= ~(E1000_MANC_ARP_EN);

                /* enable receiving management packets to the host */
                if (adapter->hw.mac.type >= e1000_82571) {
                  manc |= E1000_MANC_EN_MNG2HOST;
#define E1000_MNG2HOST_PORT_623 (1 << 5)
#define E1000_MNG2HOST_PORT_664 (1 << 6)
                  manc2h |= E1000_MNG2HOST_PORT_623;
                  manc2h |= E1000_MNG2HOST_PORT_664;
                  E1000_WRITE_REG(&adapter->hw, E1000_MANC2H, manc2h);
            }

            E1000_WRITE_REG(&adapter->hw, E1000_MANC, manc);
      }
}

/*
 * Give control back to hardware management
 * controller if there is one.
 */
static void
em_release_manageability(struct adapter *adapter)
{
      if (adapter->has_manage) {
            int manc = E1000_READ_REG(&adapter->hw, E1000_MANC);

            /* re-enable hardware interception of ARP */
            manc |= E1000_MANC_ARP_EN;

            if (adapter->hw.mac.type >= e1000_82571)
                  manc &= ~E1000_MANC_EN_MNG2HOST;

            E1000_WRITE_REG(&adapter->hw, E1000_MANC, manc);
      }
}

/*
 * em_get_hw_control sets {CTRL_EXT|FWSM}:DRV_LOAD bit.
 * For ASF and Pass Through versions of f/w this means that
 * the driver is loaded. For AMT version (only with 82573)
 * of the f/w this means that the network i/f is open.
 *
 */
static void
em_get_hw_control(struct adapter *adapter)
{
      u32 ctrl_ext, swsm;

      /* Let firmware know the driver has taken over */
      switch (adapter->hw.mac.type) {
      case e1000_82573:
            swsm = E1000_READ_REG(&adapter->hw, E1000_SWSM);
            E1000_WRITE_REG(&adapter->hw, E1000_SWSM,
                swsm | E1000_SWSM_DRV_LOAD);
            break;
      case e1000_82571:
      case e1000_82572:
      case e1000_80003es2lan:
      case e1000_ich8lan:
      case e1000_ich9lan:
            ctrl_ext = E1000_READ_REG(&adapter->hw, E1000_CTRL_EXT);
            E1000_WRITE_REG(&adapter->hw, E1000_CTRL_EXT,
                ctrl_ext | E1000_CTRL_EXT_DRV_LOAD);
            break;
      default:
            break;
      }
}

/*
 * em_release_hw_control resets {CTRL_EXT|FWSM}:DRV_LOAD bit.
 * For ASF and Pass Through versions of f/w this means that the
 * driver is no longer loaded. For AMT version (only with 82573) i
 * of the f/w this means that the network i/f is closed.
 *
 */
static void
em_release_hw_control(struct adapter *adapter)
{
      u32 ctrl_ext, swsm;

      /* Let firmware taken over control of h/w */
      switch (adapter->hw.mac.type) {
      case e1000_82573:
            swsm = E1000_READ_REG(&adapter->hw, E1000_SWSM);
            E1000_WRITE_REG(&adapter->hw, E1000_SWSM,
                swsm & ~E1000_SWSM_DRV_LOAD);
            break;
      case e1000_82571:
      case e1000_82572:
      case e1000_80003es2lan:
      case e1000_ich8lan:
      case e1000_ich9lan:
            ctrl_ext = E1000_READ_REG(&adapter->hw, E1000_CTRL_EXT);
            E1000_WRITE_REG(&adapter->hw, E1000_CTRL_EXT,
                ctrl_ext & ~E1000_CTRL_EXT_DRV_LOAD);
            break;
      default:
            break;

      }
}

static int
em_is_valid_ether_addr(uint8_t *addr)
{
      char zero_addr[6] = { 0, 0, 0, 0, 0, 0 };

      if ((addr[0] & 1) || (!bcmp(addr, zero_addr, ETHER_ADDR_LEN))) {
            return (FALSE);
      }

      return (TRUE);
}

/*
 * NOTE: the following routines using the e1000 
 *    naming style are provided to the shared
 *    code which expects that rather than 'em'
 */

void
e1000_write_pci_cfg(struct e1000_hw *hw, uint32_t reg, uint16_t *value)
{
      pci_write_config(((struct e1000_osdep *)hw->back)->dev, reg, *value, 2);
}

void
e1000_read_pci_cfg(struct e1000_hw *hw, uint32_t reg, uint16_t *value)
{
      *value = pci_read_config(((struct e1000_osdep *)hw->back)->dev, reg, 2);
}

void
e1000_pci_set_mwi(struct e1000_hw *hw)
{
      pci_write_config(((struct e1000_osdep *)hw->back)->dev, PCIR_COMMAND,
          (hw->bus.pci_cmd_word | CMD_MEM_WRT_INVALIDATE), 2);
}

void
e1000_pci_clear_mwi(struct e1000_hw *hw)
{
      pci_write_config(((struct e1000_osdep *)hw->back)->dev, PCIR_COMMAND,
          (hw->bus.pci_cmd_word & ~CMD_MEM_WRT_INVALIDATE), 2);
}

/*
 * Read the PCI Express capabilities
 */
int32_t
e1000_read_pcie_cap_reg(struct e1000_hw *hw, uint32_t reg, uint16_t *value)
{
      int32_t           error = E1000_SUCCESS;
      uint16_t    cap_off;

      switch (hw->mac.type) {

            case e1000_82571:
            case e1000_82572:
            case e1000_82573:
            case e1000_80003es2lan:
                  cap_off = 0xE0;
                  e1000_read_pci_cfg(hw, cap_off + reg, value);
                  break;
            default:
                  error = ~E1000_NOT_IMPLEMENTED;
                  break;
      }

      return (error);   
}

int32_t
e1000_alloc_zeroed_dev_spec_struct(struct e1000_hw *hw, uint32_t size)
{
      int32_t error = 0;

      hw->dev_spec = malloc(size, M_DEVBUF, M_NOWAIT | M_ZERO);
      if (hw->dev_spec == NULL)
            error = ENOMEM;

      return (error);
}

void
e1000_free_dev_spec_struct(struct e1000_hw *hw)
{
      if (hw->dev_spec != NULL)
            free(hw->dev_spec, M_DEVBUF);
      return;
}

/*
 * Enable PCI Wake On Lan capability
 */
void
em_enable_wakeup(device_t dev)
{
      u16     cap, status;
      u8      id;

      /* First find the capabilities pointer*/
      cap = pci_read_config(dev, PCIR_CAP_PTR, 2);
      /* Read the PM Capabilities */
      id = pci_read_config(dev, cap, 1);
      if (id != PCIY_PMG)     /* Something wrong */
            return;
      /* OK, we have the power capabilities, so
         now get the status register */
      cap += PCIR_POWER_STATUS;
      status = pci_read_config(dev, cap, 2);
      status |= PCIM_PSTAT_PME | PCIM_PSTAT_PMEENABLE;
      pci_write_config(dev, cap, status, 2);
      return;
}


/*********************************************************************
* 82544 Coexistence issue workaround.
*    There are 2 issues.
*       1. Transmit Hang issue.
*    To detect this issue, following equation can be used...
*       SIZE[3:0] + ADDR[2:0] = SUM[3:0].
*       If SUM[3:0] is in between 1 to 4, we will have this issue.
*
*       2. DAC issue.
*    To detect this issue, following equation can be used...
*       SIZE[3:0] + ADDR[2:0] = SUM[3:0].
*       If SUM[3:0] is in between 9 to c, we will have this issue.
*
*
*    WORKAROUND:
*       Make sure we do not have ending address
*       as 1,2,3,4(Hang) or 9,a,b,c (DAC)
*
*************************************************************************/
static uint32_t
em_fill_descriptors (bus_addr_t address, uint32_t length,
            PDESC_ARRAY desc_array)
{
      /* Since issue is sensitive to length and address.*/
      /* Let us first check the address...*/
      uint32_t safe_terminator;
      if (length <= 4) {
            desc_array->descriptor[0].address = address;
            desc_array->descriptor[0].length = length;
            desc_array->elements = 1;
            return (desc_array->elements);
      }
      safe_terminator = (uint32_t)((((uint32_t)address & 0x7) +
          (length & 0xF)) & 0xF);
      /* if it does not fall between 0x1 to 0x4 and 0x9 to 0xC then return */
      if (safe_terminator == 0   ||
      (safe_terminator > 4   &&
      safe_terminator < 9)   ||
      (safe_terminator > 0xC &&
      safe_terminator <= 0xF)) {
            desc_array->descriptor[0].address = address;
            desc_array->descriptor[0].length = length;
            desc_array->elements = 1;
            return (desc_array->elements);
      }

      desc_array->descriptor[0].address = address;
      desc_array->descriptor[0].length = length - 4;
      desc_array->descriptor[1].address = address + (length - 4);
      desc_array->descriptor[1].length = 4;
      desc_array->elements = 2;
      return (desc_array->elements);
}

/**********************************************************************
 *
 *  Update the board statistics counters.
 *
 **********************************************************************/
static void
em_update_stats_counters(struct adapter *adapter)
{
      struct ifnet   *ifp;

      if(adapter->hw.phy.media_type == e1000_media_type_copper ||
         (E1000_READ_REG(&adapter->hw, E1000_STATUS) & E1000_STATUS_LU)) {
            adapter->stats.symerrs += E1000_READ_REG(&adapter->hw, E1000_SYMERRS);
            adapter->stats.sec += E1000_READ_REG(&adapter->hw, E1000_SEC);
      }
      adapter->stats.crcerrs += E1000_READ_REG(&adapter->hw, E1000_CRCERRS);
      adapter->stats.mpc += E1000_READ_REG(&adapter->hw, E1000_MPC);
      adapter->stats.scc += E1000_READ_REG(&adapter->hw, E1000_SCC);
      adapter->stats.ecol += E1000_READ_REG(&adapter->hw, E1000_ECOL);

      adapter->stats.mcc += E1000_READ_REG(&adapter->hw, E1000_MCC);
      adapter->stats.latecol += E1000_READ_REG(&adapter->hw, E1000_LATECOL);
      adapter->stats.colc += E1000_READ_REG(&adapter->hw, E1000_COLC);
      adapter->stats.dc += E1000_READ_REG(&adapter->hw, E1000_DC);
      adapter->stats.rlec += E1000_READ_REG(&adapter->hw, E1000_RLEC);
      adapter->stats.xonrxc += E1000_READ_REG(&adapter->hw, E1000_XONRXC);
      adapter->stats.xontxc += E1000_READ_REG(&adapter->hw, E1000_XONTXC);
      adapter->stats.xoffrxc += E1000_READ_REG(&adapter->hw, E1000_XOFFRXC);
      adapter->stats.xofftxc += E1000_READ_REG(&adapter->hw, E1000_XOFFTXC);
      adapter->stats.fcruc += E1000_READ_REG(&adapter->hw, E1000_FCRUC);
      adapter->stats.prc64 += E1000_READ_REG(&adapter->hw, E1000_PRC64);
      adapter->stats.prc127 += E1000_READ_REG(&adapter->hw, E1000_PRC127);
      adapter->stats.prc255 += E1000_READ_REG(&adapter->hw, E1000_PRC255);
      adapter->stats.prc511 += E1000_READ_REG(&adapter->hw, E1000_PRC511);
      adapter->stats.prc1023 += E1000_READ_REG(&adapter->hw, E1000_PRC1023);
      adapter->stats.prc1522 += E1000_READ_REG(&adapter->hw, E1000_PRC1522);
      adapter->stats.gprc += E1000_READ_REG(&adapter->hw, E1000_GPRC);
      adapter->stats.bprc += E1000_READ_REG(&adapter->hw, E1000_BPRC);
      adapter->stats.mprc += E1000_READ_REG(&adapter->hw, E1000_MPRC);
      adapter->stats.gptc += E1000_READ_REG(&adapter->hw, E1000_GPTC);

      /* For the 64-bit byte counters the low dword must be read first. */
      /* Both registers clear on the read of the high dword */

      adapter->stats.gorc += E1000_READ_REG(&adapter->hw, E1000_GORCH);
      adapter->stats.gotc += E1000_READ_REG(&adapter->hw, E1000_GOTCH);

      adapter->stats.rnbc += E1000_READ_REG(&adapter->hw, E1000_RNBC);
      adapter->stats.ruc += E1000_READ_REG(&adapter->hw, E1000_RUC);
      adapter->stats.rfc += E1000_READ_REG(&adapter->hw, E1000_RFC);
      adapter->stats.roc += E1000_READ_REG(&adapter->hw, E1000_ROC);
      adapter->stats.rjc += E1000_READ_REG(&adapter->hw, E1000_RJC);

      adapter->stats.tor += E1000_READ_REG(&adapter->hw, E1000_TORH);
      adapter->stats.tot += E1000_READ_REG(&adapter->hw, E1000_TOTH);

      adapter->stats.tpr += E1000_READ_REG(&adapter->hw, E1000_TPR);
      adapter->stats.tpt += E1000_READ_REG(&adapter->hw, E1000_TPT);
      adapter->stats.ptc64 += E1000_READ_REG(&adapter->hw, E1000_PTC64);
      adapter->stats.ptc127 += E1000_READ_REG(&adapter->hw, E1000_PTC127);
      adapter->stats.ptc255 += E1000_READ_REG(&adapter->hw, E1000_PTC255);
      adapter->stats.ptc511 += E1000_READ_REG(&adapter->hw, E1000_PTC511);
      adapter->stats.ptc1023 += E1000_READ_REG(&adapter->hw, E1000_PTC1023);
      adapter->stats.ptc1522 += E1000_READ_REG(&adapter->hw, E1000_PTC1522);
      adapter->stats.mptc += E1000_READ_REG(&adapter->hw, E1000_MPTC);
      adapter->stats.bptc += E1000_READ_REG(&adapter->hw, E1000_BPTC);

      if (adapter->hw.mac.type >= e1000_82543) {
            adapter->stats.algnerrc += 
            E1000_READ_REG(&adapter->hw, E1000_ALGNERRC);
            adapter->stats.rxerrc += 
            E1000_READ_REG(&adapter->hw, E1000_RXERRC);
            adapter->stats.tncrs += 
            E1000_READ_REG(&adapter->hw, E1000_TNCRS);
            adapter->stats.cexterr += 
            E1000_READ_REG(&adapter->hw, E1000_CEXTERR);
            adapter->stats.tsctc += 
            E1000_READ_REG(&adapter->hw, E1000_TSCTC);
            adapter->stats.tsctfc += 
            E1000_READ_REG(&adapter->hw, E1000_TSCTFC);
      }
      ifp = adapter->ifp;

      ifp->if_collisions = adapter->stats.colc;

      /* Rx Errors */
      ifp->if_ierrors = adapter->dropped_pkts + adapter->stats.rxerrc +
          adapter->stats.crcerrs + adapter->stats.algnerrc +
          adapter->stats.ruc + adapter->stats.roc +
          adapter->stats.mpc + adapter->stats.cexterr;

      /* Tx Errors */
      ifp->if_oerrors = adapter->stats.ecol +
          adapter->stats.latecol + adapter->watchdog_events;
}


/**********************************************************************
 *
 *  This routine is called only when em_display_debug_stats is enabled.
 *  This routine provides a way to take a look at important statistics
 *  maintained by the driver and hardware.
 *
 **********************************************************************/
static void
em_print_debug_info(struct adapter *adapter)
{
      device_t dev = adapter->dev;
      uint8_t *hw_addr = adapter->hw.hw_addr;

      device_printf(dev, "Adapter hardware address = %p \n", hw_addr);
      device_printf(dev, "CTRL = 0x%x RCTL = 0x%x \n",
          E1000_READ_REG(&adapter->hw, E1000_CTRL),
          E1000_READ_REG(&adapter->hw, E1000_RCTL));
      device_printf(dev, "Packet buffer = Tx=%dk Rx=%dk \n",
          ((E1000_READ_REG(&adapter->hw, E1000_PBA) & 0xffff0000) >> 16),\
          (E1000_READ_REG(&adapter->hw, E1000_PBA) & 0xffff) );
      device_printf(dev, "Flow control watermarks high = %d low = %d\n",
          adapter->hw.fc.high_water,
          adapter->hw.fc.low_water);
      device_printf(dev, "tx_int_delay = %d, tx_abs_int_delay = %d\n",
          E1000_READ_REG(&adapter->hw, E1000_TIDV),
          E1000_READ_REG(&adapter->hw, E1000_TADV));
      device_printf(dev, "rx_int_delay = %d, rx_abs_int_delay = %d\n",
          E1000_READ_REG(&adapter->hw, E1000_RDTR),
          E1000_READ_REG(&adapter->hw, E1000_RADV));
      device_printf(dev, "fifo workaround = %lld, fifo_reset_count = %lld\n",
          (long long)adapter->tx_fifo_wrk_cnt,
          (long long)adapter->tx_fifo_reset_cnt);
      device_printf(dev, "hw tdh = %d, hw tdt = %d\n",
          E1000_READ_REG(&adapter->hw, E1000_TDH(0)),
          E1000_READ_REG(&adapter->hw, E1000_TDT(0)));
      device_printf(dev, "hw rdh = %d, hw rdt = %d\n",
          E1000_READ_REG(&adapter->hw, E1000_RDH(0)),
          E1000_READ_REG(&adapter->hw, E1000_RDT(0)));
      device_printf(dev, "Num Tx descriptors avail = %d\n",
          adapter->num_tx_desc_avail);
      device_printf(dev, "Tx Descriptors not avail1 = %ld\n",
          adapter->no_tx_desc_avail1);
      device_printf(dev, "Tx Descriptors not avail2 = %ld\n",
          adapter->no_tx_desc_avail2);
      device_printf(dev, "Std mbuf failed = %ld\n",
          adapter->mbuf_alloc_failed);
      device_printf(dev, "Std mbuf cluster failed = %ld\n",
          adapter->mbuf_cluster_failed);
      device_printf(dev, "Driver dropped packets = %ld\n",
          adapter->dropped_pkts);
      device_printf(dev, "Driver tx dma failure in encap = %ld\n",
            adapter->no_tx_dma_setup);
}

static void
em_print_hw_stats(struct adapter *adapter)
{
      device_t dev = adapter->dev;

      device_printf(dev, "Excessive collisions = %lld\n",
          (long long)adapter->stats.ecol);
#if   (DEBUG_HW > 0)  /* Dont output these errors normally */
      device_printf(dev, "Symbol errors = %lld\n",
          (long long)adapter->stats.symerrs);
#endif
      device_printf(dev, "Sequence errors = %lld\n",
          (long long)adapter->stats.sec);
      device_printf(dev, "Defer count = %lld\n",
          (long long)adapter->stats.dc);
      device_printf(dev, "Missed Packets = %lld\n",
          (long long)adapter->stats.mpc);
      device_printf(dev, "Receive No Buffers = %lld\n",
          (long long)adapter->stats.rnbc);
      /* RLEC is inaccurate on some hardware, calculate our own. */
      device_printf(dev, "Receive Length Errors = %lld\n",
          ((long long)adapter->stats.roc + (long long)adapter->stats.ruc));
      device_printf(dev, "Receive errors = %lld\n",
          (long long)adapter->stats.rxerrc);
      device_printf(dev, "Crc errors = %lld\n",
          (long long)adapter->stats.crcerrs);
      device_printf(dev, "Alignment errors = %lld\n",
          (long long)adapter->stats.algnerrc);
      /* On 82575 these are collision counts */
      device_printf(dev, "Collision/Carrier extension errors = %lld\n",
          (long long)adapter->stats.cexterr);
      device_printf(dev, "RX overruns = %ld\n", adapter->rx_overruns);
      device_printf(dev, "watchdog timeouts = %ld\n",
          adapter->watchdog_events);
      device_printf(dev, "XON Rcvd = %lld\n",
          (long long)adapter->stats.xonrxc);
      device_printf(dev, "XON Xmtd = %lld\n",
          (long long)adapter->stats.xontxc);
      device_printf(dev, "XOFF Rcvd = %lld\n",
          (long long)adapter->stats.xoffrxc);
      device_printf(dev, "XOFF Xmtd = %lld\n",
          (long long)adapter->stats.xofftxc);
      device_printf(dev, "Good Packets Rcvd = %lld\n",
          (long long)adapter->stats.gprc);
      device_printf(dev, "Good Packets Xmtd = %lld\n",
          (long long)adapter->stats.gptc);
      device_printf(dev, "TSO Contexts Xmtd = %lld\n",
          (long long)adapter->stats.tsctc);
      device_printf(dev, "TSO Contexts Failed = %lld\n",
          (long long)adapter->stats.tsctfc);
}

/**********************************************************************
 *
 *  This routine provides a way to dump out the adapter eeprom,
 *  often a useful debug/service tool. This only dumps the first
 *  32 words, stuff that matters is in that extent.
 *
 **********************************************************************/
static void
em_print_nvm_info(struct adapter *adapter)
{
      u16   eeprom_data;
      int   i, j, row = 0;

      /* Its a bit crude, but it gets the job done */
      printf("\nInterface EEPROM Dump:\n");
      printf("Offset\n0x0000  ");
      for (i = 0, j = 0; i < 32; i++, j++) {
            if (j == 8) { /* Make the offset block */
                  j = 0; ++row;
                  printf("\n0x00%x0  ",row);
            }
            e1000_read_nvm(&adapter->hw, i, 1, &eeprom_data);
            printf("%04x ", eeprom_data);
      }
      printf("\n");
}

static int
em_sysctl_debug_info(SYSCTL_HANDLER_ARGS)
{
      struct adapter *adapter;
      int error;
      int result;

      result = -1;
      error = sysctl_handle_int(oidp, &result, 0, req);

      if (error || !req->newptr)
            return (error);

      if (result == 1) {
            adapter = (struct adapter *)arg1;
            em_print_debug_info(adapter);
      }
      /*
       * This value will cause a hex dump of the
       * first 32 16-bit words of the EEPROM to
       * the screen.
       */
      if (result == 2) {
            adapter = (struct adapter *)arg1;
            em_print_nvm_info(adapter);
        }

      return (error);
}


static int
em_sysctl_stats(SYSCTL_HANDLER_ARGS)
{
      struct adapter *adapter;
      int error;
      int result;

      result = -1;
      error = sysctl_handle_int(oidp, &result, 0, req);

      if (error || !req->newptr)
            return (error);

      if (result == 1) {
            adapter = (struct adapter *)arg1;
            em_print_hw_stats(adapter);
      }

      return (error);
}

static int
em_sysctl_int_delay(SYSCTL_HANDLER_ARGS)
{
      struct em_int_delay_info *info;
      struct adapter *adapter;
      uint32_t regval;
      int error;
      int usecs;
      int ticks;

      info = (struct em_int_delay_info *)arg1;
      usecs = info->value;
      error = sysctl_handle_int(oidp, &usecs, 0, req);
      if (error != 0 || req->newptr == NULL)
            return (error);
      if (usecs < 0 || usecs > EM_TICKS_TO_USECS(65535))
            return (EINVAL);
      info->value = usecs;
      ticks = EM_USECS_TO_TICKS(usecs);

      adapter = info->adapter;
      
      EM_CORE_LOCK(adapter);
      regval = E1000_READ_OFFSET(&adapter->hw, info->offset);
      regval = (regval & ~0xffff) | (ticks & 0xffff);
      /* Handle a few special cases. */
      switch (info->offset) {
      case E1000_RDTR:
            break;
      case E1000_TIDV:
            if (ticks == 0) {
                  adapter->txd_cmd &= ~E1000_TXD_CMD_IDE;
                  /* Don't write 0 into the TIDV register. */
                  regval++;
            } else
                  if (adapter->hw.mac.type != e1000_82575)
                        adapter->txd_cmd |= E1000_TXD_CMD_IDE;
            break;
      }
      E1000_WRITE_OFFSET(&adapter->hw, info->offset, regval);
      EM_CORE_UNLOCK(adapter);
      return (0);
}

static void
em_add_int_delay_sysctl(struct adapter *adapter, const char *name,
      const char *description, struct em_int_delay_info *info,
      int offset, int value)
{
      info->adapter = adapter;
      info->offset = offset;
      info->value = value;
      SYSCTL_ADD_PROC(device_get_sysctl_ctx(adapter->dev),
          SYSCTL_CHILDREN(device_get_sysctl_tree(adapter->dev)),
          OID_AUTO, name, CTLTYPE_INT|CTLFLAG_RW,
          info, 0, em_sysctl_int_delay, "I", description);
}

#ifdef EM_FAST_IRQ
static void
em_add_rx_process_limit(struct adapter *adapter, const char *name,
      const char *description, int *limit, int value)
{
      *limit = value;
      SYSCTL_ADD_INT(device_get_sysctl_ctx(adapter->dev),
          SYSCTL_CHILDREN(device_get_sysctl_tree(adapter->dev)),
          OID_AUTO, name, CTLTYPE_INT|CTLFLAG_RW, limit, value, description);
}
#endif

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