ixgb_main.c

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

  
  Copyright(c) 1999 - 2006 Intel Corporation. All rights reserved.
  
  This program is free software; you can redistribute it and/or modify it 
  under the terms of the GNU General Public License as published by the Free 
  Software Foundation; either version 2 of the License, or (at your option) 
  any later version.
  
  This program is distributed in the hope that it will be useful, but WITHOUT 
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 
  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for 
  more details.
  
  You should have received a copy of the GNU General Public License along with
  this program; if not, write to the Free Software Foundation, Inc., 59 
  Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  
  The full GNU General Public License is included in this distribution in the
  file called LICENSE.
  
  Contact Information:
  Linux NICS <linux.nics@intel.com>
  Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497

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

#include "ixgb.h"

char ixgb_driver_name[] = "ixgb";
static char ixgb_driver_string[] = "Intel(R) PRO/10GbE Network Driver";

#ifndef CONFIG_IXGB_NAPI
#define DRIVERNAPI
#else
#define DRIVERNAPI "-NAPI"
#endif
#define DRV_VERSION		"1.0.109-k2"DRIVERNAPI
char ixgb_driver_version[] = DRV_VERSION;
static char ixgb_copyright[] = "Copyright (c) 1999-2006 Intel Corporation.";

/* ixgb_pci_tbl - PCI Device ID Table
 *
 * Wildcard entries (PCI_ANY_ID) should come last
 * Last entry must be all 0s
 *
 * { Vendor ID, Device ID, SubVendor ID, SubDevice ID,
 *   Class, Class Mask, private data (not used) }
 */
static struct pci_device_id ixgb_pci_tbl[] = {
	{INTEL_VENDOR_ID, IXGB_DEVICE_ID_82597EX,
	 PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
	{INTEL_VENDOR_ID, IXGB_DEVICE_ID_82597EX_CX4,
	 PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
	{INTEL_VENDOR_ID, IXGB_DEVICE_ID_82597EX_SR,
	 PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
	{INTEL_VENDOR_ID, IXGB_DEVICE_ID_82597EX_LR,  
	 PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},

	/* required last entry */
	{0,}
};

MODULE_DEVICE_TABLE(pci, ixgb_pci_tbl);

/* Local Function Prototypes */

int ixgb_up(struct ixgb_adapter *adapter);
void ixgb_down(struct ixgb_adapter *adapter, boolean_t kill_watchdog);
void ixgb_reset(struct ixgb_adapter *adapter);
int ixgb_setup_tx_resources(struct ixgb_adapter *adapter);
int ixgb_setup_rx_resources(struct ixgb_adapter *adapter);
void ixgb_free_tx_resources(struct ixgb_adapter *adapter);
void ixgb_free_rx_resources(struct ixgb_adapter *adapter);
void ixgb_update_stats(struct ixgb_adapter *adapter);

static int ixgb_init_module(void);
static void ixgb_exit_module(void);
static int ixgb_probe(struct pci_dev *pdev, const struct pci_device_id *ent);
static void __devexit ixgb_remove(struct pci_dev *pdev);
static int ixgb_sw_init(struct ixgb_adapter *adapter);
static int ixgb_open(struct net_device *netdev);
static int ixgb_close(struct net_device *netdev);
static void ixgb_configure_tx(struct ixgb_adapter *adapter);
static void ixgb_configure_rx(struct ixgb_adapter *adapter);
static void ixgb_setup_rctl(struct ixgb_adapter *adapter);
static void ixgb_clean_tx_ring(struct ixgb_adapter *adapter);
static void ixgb_clean_rx_ring(struct ixgb_adapter *adapter);
static void ixgb_set_multi(struct net_device *netdev);
static void ixgb_watchdog(unsigned long data);
static int ixgb_xmit_frame(struct sk_buff *skb, struct net_device *netdev);
static struct net_device_stats *ixgb_get_stats(struct net_device *netdev);
static int ixgb_change_mtu(struct net_device *netdev, int new_mtu);
static int ixgb_set_mac(struct net_device *netdev, void *p);
static irqreturn_t ixgb_intr(int irq, void *data, struct pt_regs *regs);
static boolean_t ixgb_clean_tx_irq(struct ixgb_adapter *adapter);

#ifdef CONFIG_IXGB_NAPI
static int ixgb_clean(struct net_device *netdev, int *budget);
static boolean_t ixgb_clean_rx_irq(struct ixgb_adapter *adapter,
				   int *work_done, int work_to_do);
#else
static boolean_t ixgb_clean_rx_irq(struct ixgb_adapter *adapter);
#endif
static void ixgb_alloc_rx_buffers(struct ixgb_adapter *adapter);
void ixgb_set_ethtool_ops(struct net_device *netdev);
static void ixgb_tx_timeout(struct net_device *dev);
static void ixgb_tx_timeout_task(struct net_device *dev);
static void ixgb_vlan_rx_register(struct net_device *netdev,
				  struct vlan_group *grp);
static void ixgb_vlan_rx_add_vid(struct net_device *netdev, uint16_t vid);
static void ixgb_vlan_rx_kill_vid(struct net_device *netdev, uint16_t vid);
static void ixgb_restore_vlan(struct ixgb_adapter *adapter);

#ifdef CONFIG_NET_POLL_CONTROLLER
/* for netdump / net console */
static void ixgb_netpoll(struct net_device *dev);
#endif

/* Exported from other modules */

extern void ixgb_check_options(struct ixgb_adapter *adapter);

static struct pci_driver ixgb_driver = {
	.name     = ixgb_driver_name,
	.id_table = ixgb_pci_tbl,
	.probe    = ixgb_probe,
	.remove   = __devexit_p(ixgb_remove),
};

MODULE_AUTHOR("Intel Corporation, <linux.nics@intel.com>");
MODULE_DESCRIPTION("Intel(R) PRO/10GbE Network Driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);

#define DEFAULT_DEBUG_LEVEL_SHIFT 3
static int debug = DEFAULT_DEBUG_LEVEL_SHIFT;
module_param(debug, int, 0);
MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)");

/* some defines for controlling descriptor fetches in h/w */
#define RXDCTL_WTHRESH_DEFAULT 16	/* chip writes back at this many or RXT0 */
#define RXDCTL_PTHRESH_DEFAULT 0		/* chip considers prefech below
						 * this */
#define RXDCTL_HTHRESH_DEFAULT 0		/* chip will only prefetch if tail
						 * is pushed this many descriptors
						 * from head */

/**
 * ixgb_init_module - Driver Registration Routine
 *
 * ixgb_init_module is the first routine called when the driver is
 * loaded. All it does is register with the PCI subsystem.
 **/

static int __init
ixgb_init_module(void)
{
	printk(KERN_INFO "%s - version %s\n",
	       ixgb_driver_string, ixgb_driver_version);

	printk(KERN_INFO "%s\n", ixgb_copyright);

	return pci_module_init(&ixgb_driver);
}

module_init(ixgb_init_module);

/**
 * ixgb_exit_module - Driver Exit Cleanup Routine
 *
 * ixgb_exit_module is called just before the driver is removed
 * from memory.
 **/

static void __exit
ixgb_exit_module(void)
{
	pci_unregister_driver(&ixgb_driver);
}

module_exit(ixgb_exit_module);

/**
 * ixgb_irq_disable - Mask off interrupt generation on the NIC
 * @adapter: board private structure
 **/

static void
ixgb_irq_disable(struct ixgb_adapter *adapter)
{
	atomic_inc(&adapter->irq_sem);
	IXGB_WRITE_REG(&adapter->hw, IMC, ~0);
	IXGB_WRITE_FLUSH(&adapter->hw);
	synchronize_irq(adapter->pdev->irq);
}

/**
 * ixgb_irq_enable - Enable default interrupt generation settings
 * @adapter: board private structure
 **/

static void
ixgb_irq_enable(struct ixgb_adapter *adapter)
{
	if(atomic_dec_and_test(&adapter->irq_sem)) {
		IXGB_WRITE_REG(&adapter->hw, IMS,
			       IXGB_INT_RXT0 | IXGB_INT_RXDMT0 | IXGB_INT_TXDW |
			       IXGB_INT_LSC);
		IXGB_WRITE_FLUSH(&adapter->hw);
	}
}

int
ixgb_up(struct ixgb_adapter *adapter)
{
	struct net_device *netdev = adapter->netdev;
	int err;
	int max_frame = netdev->mtu + ENET_HEADER_SIZE + ENET_FCS_LENGTH;
	struct ixgb_hw *hw = &adapter->hw;

	/* hardware has been reset, we need to reload some things */

	ixgb_rar_set(hw, netdev->dev_addr, 0);
	ixgb_set_multi(netdev);

	ixgb_restore_vlan(adapter);

	ixgb_configure_tx(adapter);
	ixgb_setup_rctl(adapter);
	ixgb_configure_rx(adapter);
	ixgb_alloc_rx_buffers(adapter);

	/* disable interrupts and get the hardware into a known state */
	IXGB_WRITE_REG(&adapter->hw, IMC, 0xffffffff);

#ifdef CONFIG_PCI_MSI
	{
	boolean_t pcix = (IXGB_READ_REG(&adapter->hw, STATUS) & 
						  IXGB_STATUS_PCIX_MODE) ? TRUE : FALSE;
	adapter->have_msi = TRUE;

	if (!pcix)
	   adapter->have_msi = FALSE;
	else if((err = pci_enable_msi(adapter->pdev))) {
		DPRINTK(PROBE, ERR,
		 "Unable to allocate MSI interrupt Error: %d\n", err);
		adapter->have_msi = FALSE;
		/* proceed to try to request regular interrupt */
	}
	}

#endif
	if((err = request_irq(adapter->pdev->irq, &ixgb_intr,
				  IRQF_SHARED | IRQF_SAMPLE_RANDOM,
			          netdev->name, netdev))) {
		DPRINTK(PROBE, ERR,
		 "Unable to allocate interrupt Error: %d\n", err);
		return err;
	}

	if((hw->max_frame_size != max_frame) ||
		(hw->max_frame_size !=
		(IXGB_READ_REG(hw, MFS) >> IXGB_MFS_SHIFT))) {

		hw->max_frame_size = max_frame;

		IXGB_WRITE_REG(hw, MFS, hw->max_frame_size << IXGB_MFS_SHIFT);

		if(hw->max_frame_size >
		   IXGB_MAX_ENET_FRAME_SIZE_WITHOUT_FCS + ENET_FCS_LENGTH) {
			uint32_t ctrl0 = IXGB_READ_REG(hw, CTRL0);

			if(!(ctrl0 & IXGB_CTRL0_JFE)) {
				ctrl0 |= IXGB_CTRL0_JFE;
				IXGB_WRITE_REG(hw, CTRL0, ctrl0);
			}
		}
	}

	mod_timer(&adapter->watchdog_timer, jiffies);

#ifdef CONFIG_IXGB_NAPI
	netif_poll_enable(netdev);
#endif
	ixgb_irq_enable(adapter);

	return 0;
}

void
ixgb_down(struct ixgb_adapter *adapter, boolean_t kill_watchdog)
{
	struct net_device *netdev = adapter->netdev;

	ixgb_irq_disable(adapter);
	free_irq(adapter->pdev->irq, netdev);
#ifdef CONFIG_PCI_MSI
	if(adapter->have_msi == TRUE)
		pci_disable_msi(adapter->pdev);

#endif
	if(kill_watchdog)
		del_timer_sync(&adapter->watchdog_timer);
#ifdef CONFIG_IXGB_NAPI
	netif_poll_disable(netdev);
#endif
	adapter->link_speed = 0;
	adapter->link_duplex = 0;
	netif_carrier_off(netdev);
	netif_stop_queue(netdev);

	ixgb_reset(adapter);
	ixgb_clean_tx_ring(adapter);
	ixgb_clean_rx_ring(adapter);
}

void
ixgb_reset(struct ixgb_adapter *adapter)
{

	ixgb_adapter_stop(&adapter->hw);
	if(!ixgb_init_hw(&adapter->hw))
		DPRINTK(PROBE, ERR, "ixgb_init_hw failed.\n");
}

/**
 * ixgb_probe - Device Initialization Routine
 * @pdev: PCI device information struct
 * @ent: entry in ixgb_pci_tbl
 *
 * Returns 0 on success, negative on failure
 *
 * ixgb_probe initializes an adapter identified by a pci_dev structure.
 * The OS initialization, configuring of the adapter private structure,
 * and a hardware reset occur.
 **/

static int __devinit
ixgb_probe(struct pci_dev *pdev,
		const struct pci_device_id *ent)
{
	struct net_device *netdev = NULL;
	struct ixgb_adapter *adapter;
	static int cards_found = 0;
	unsigned long mmio_start;
	int mmio_len;
	int pci_using_dac;
	int i;
	int err;

	if((err = pci_enable_device(pdev)))
		return err;

	if(!(err = pci_set_dma_mask(pdev, DMA_64BIT_MASK)) &&
	   !(err = pci_set_consistent_dma_mask(pdev, DMA_64BIT_MASK))) {
		pci_using_dac = 1;
	} else {
		if((err = pci_set_dma_mask(pdev, DMA_32BIT_MASK)) ||
		   (err = pci_set_consistent_dma_mask(pdev, DMA_32BIT_MASK))) {
			printk(KERN_ERR
			 "ixgb: No usable DMA configuration, aborting\n");
			goto err_dma_mask;
		}
		pci_using_dac = 0;
	}

	if((err = pci_request_regions(pdev, ixgb_driver_name)))
		goto err_request_regions;

	pci_set_master(pdev);

	netdev = alloc_etherdev(sizeof(struct ixgb_adapter));
	if(!netdev) {
		err = -ENOMEM;
		goto err_alloc_etherdev;
	}

	SET_MODULE_OWNER(netdev);
	SET_NETDEV_DEV(netdev, &pdev->dev);

	pci_set_drvdata(pdev, netdev);
	adapter = netdev_priv(netdev);
	adapter->netdev = netdev;
	adapter->pdev = pdev;
	adapter->hw.back = adapter;
	adapter->msg_enable = netif_msg_init(debug, DEFAULT_DEBUG_LEVEL_SHIFT);

	mmio_start = pci_resource_start(pdev, BAR_0);
	mmio_len = pci_resource_len(pdev, BAR_0);

	adapter->hw.hw_addr = ioremap(mmio_start, mmio_len);
	if(!adapter->hw.hw_addr) {
		err = -EIO;
		goto err_ioremap;
	}

	for(i = BAR_1; i <= BAR_5; i++) {
		if(pci_resource_len(pdev, i) == 0)
			continue;
		if(pci_resource_flags(pdev, i) & IORESOURCE_IO) {
			adapter->hw.io_base = pci_resource_start(pdev, i);
			break;
		}
	}

	netdev->open = &ixgb_open;
	netdev->stop = &ixgb_close;
	netdev->hard_start_xmit = &ixgb_xmit_frame;
	netdev->get_stats = &ixgb_get_stats;
	netdev->set_multicast_list = &ixgb_set_multi;
	netdev->set_mac_address = &ixgb_set_mac;
	netdev->change_mtu = &ixgb_change_mtu;
	ixgb_set_ethtool_ops(netdev);
	netdev->tx_timeout = &ixgb_tx_timeout;
	netdev->watchdog_timeo = 5 * HZ;
#ifdef CONFIG_IXGB_NAPI
	netdev->poll = &ixgb_clean;
	netdev->weight = 64;
#endif
	netdev->vlan_rx_register = ixgb_vlan_rx_register;
	netdev->vlan_rx_add_vid = ixgb_vlan_rx_add_vid;
	netdev->vlan_rx_kill_vid = ixgb_vlan_rx_kill_vid;
#ifdef CONFIG_NET_POLL_CONTROLLER
	netdev->poll_controller = ixgb_netpoll;
#endif

	strcpy(netdev->name, pci_name(pdev));
	netdev->mem_start = mmio_start;
	netdev->mem_end = mmio_start + mmio_len;
	netdev->base_addr = adapter->hw.io_base;

	adapter->bd_number = cards_found;
	adapter->link_speed = 0;
	adapter->link_duplex = 0;

	/* setup the private structure */

	if((err = ixgb_sw_init(adapter)))
		goto err_sw_init;

	netdev->features = NETIF_F_SG |
			   NETIF_F_HW_CSUM |
			   NETIF_F_HW_VLAN_TX |
			   NETIF_F_HW_VLAN_RX |
			   NETIF_F_HW_VLAN_FILTER;
#ifdef NETIF_F_TSO
	netdev->features |= NETIF_F_TSO;
#endif
#ifdef NETIF_F_LLTX
	netdev->features |= NETIF_F_LLTX;
#endif

	if(pci_using_dac)
		netdev->features |= NETIF_F_HIGHDMA;

	/* make sure the EEPROM is good */

	if(!ixgb_validate_eeprom_checksum(&adapter->hw)) {
		DPRINTK(PROBE, ERR, "The EEPROM Checksum Is Not Valid\n");
		err = -EIO;
		goto err_eeprom;
	}

	ixgb_get_ee_mac_addr(&adapter->hw, netdev->dev_addr);
	memcpy(netdev->perm_addr, netdev->dev_addr, netdev->addr_len);

	if(!is_valid_ether_addr(netdev->perm_addr)) {
		DPRINTK(PROBE, ERR, "Invalid MAC Address\n");
		err = -EIO;
		goto err_eeprom;
	}

	adapter->part_num = ixgb_get_ee_pba_number(&adapter->hw);

	init_timer(&adapter->watchdog_timer);
	adapter->watchdog_timer.function = &ixgb_watchdog;
	adapter->watchdog_timer.data = (unsigned long)adapter;

	INIT_WORK(&adapter->tx_timeout_task,
		  (void (*)(void *))ixgb_tx_timeout_task, netdev);

	strcpy(netdev->name, "eth%d");
	if((err = register_netdev(netdev)))
		goto err_register;

	/* we're going to reset, so assume we have no link for now */

	netif_carrier_off(netdev);
	netif_stop_queue(netdev);

	DPRINTK(PROBE, INFO, "Intel(R) PRO/10GbE Network Connection\n");
	ixgb_check_options(adapter);
	/* reset the hardware with the new settings */

	ixgb_reset(adapter);

	cards_found++;
	return 0;

err_register:
err_sw_init:
err_eeprom:
	iounmap(adapter->hw.hw_addr);
err_ioremap:
	free_netdev(netdev);
err_alloc_etherdev:
	pci_release_regions(pdev);
err_request_regions:
err_dma_mask:
	pci_disable_device(pdev);
	return err;
}

/**
 * ixgb_remove - Device Removal Routine
 * @pdev: PCI device information struct
 *
 * ixgb_remove is called by the PCI subsystem to alert the driver
 * that it should release a PCI device.  The could be caused by a
 * Hot-Plug event, or because the driver is going to be removed from
 * memory.
 **/

static void __devexit
ixgb_remove(struct pci_dev *pdev)
{
	struct net_device *netdev = pci_get_drvdata(pdev);
	struct ixgb_adapter *adapter = netdev_priv(netdev);

	unregister_netdev(netdev);

	iounmap(adapter->hw.hw_addr);
	pci_release_regions(pdev);

	free_netdev(netdev);
}

/**
 * ixgb_sw_init - Initialize general software structures (struct ixgb_adapter)
 * @adapter: board private structure to initialize
 *
 * ixgb_sw_init initializes the Adapter private data structure.
 * Fields are initialized based on PCI device information and
 * OS network device settings (MTU size).
 **/

static int __devinit
ixgb_sw_init(struct ixgb_adapter *adapter)
{
	struct ixgb_hw *hw = &adapter->hw;
	struct net_device *netdev = adapter->netdev;
	struct pci_dev *pdev = adapter->pdev;

	/* PCI config space info */

	hw->vendor_id = pdev->vendor;
	hw->device_id = pdev->device;
	hw->subsystem_vendor_id = pdev->subsystem_vendor;
	hw->subsystem_id = pdev->subsystem_device;

	hw->max_frame_size = netdev->mtu + ENET_HEADER_SIZE + ENET_FCS_LENGTH;
	adapter->rx_buffer_len = hw->max_frame_size;

	if((hw->device_id == IXGB_DEVICE_ID_82597EX)
	   || (hw->device_id == IXGB_DEVICE_ID_82597EX_CX4)
	   || (hw->device_id == IXGB_DEVICE_ID_82597EX_LR)
	   || (hw->device_id == IXGB_DEVICE_ID_82597EX_SR))
			hw->mac_type = ixgb_82597;
	else {
		/* should never have loaded on this device */
		DPRINTK(PROBE, ERR, "unsupported device id\n");
	}

	/* enable flow control to be programmed */
	hw->fc.send_xon = 1;

	atomic_set(&adapter->irq_sem, 1);
	spin_lock_init(&adapter->tx_lock);

	return 0;
}

/**
 * ixgb_open - Called when a network interface is made active
 * @netdev: network interface device structure
 *
 * Returns 0 on success, negative value on failure
 *
 * The open entry point is called when a network interface is made
 * active by the system (IFF_UP).  At this point all resources needed
 * for transmit and receive operations are allocated, the interrupt
 * handler is registered with the OS, the watchdog timer is started,
 * and the stack is notified that the interface is ready.
 **/

static int
ixgb_open(struct net_device *netdev)
{
	struct ixgb_adapter *adapter = netdev_priv(netdev);
	int err;

	/* allocate transmit descriptors */

	if((err = ixgb_setup_tx_resources(adapter)))
		goto err_setup_tx;

	/* allocate receive descriptors */

	if((err = ixgb_setup_rx_resources(adapter)))
		goto err_setup_rx;

	if((err = ixgb_up(adapter)))
		goto err_up;

	return 0;

err_up:
	ixgb_free_rx_resources(adapter);
err_setup_rx:
	ixgb_free_tx_resources(adapter);
err_setup_tx:
	ixgb_reset(adapter);

	return err;
}

/**
 * ixgb_close - Disables a network interface
 * @netdev: network interface device structure
 *
 * Returns 0, this is not allowed to fail
 *
 * The close entry point is called when an interface is de-activated
 * by the OS.  The hardware is still under the drivers control, but
 * needs to be disabled.  A global MAC reset is issued to stop the
 * hardware, and all transmit and receive resources are freed.
 **/

static int
ixgb_close(struct net_device *netdev)
{
	struct ixgb_adapter *adapter = netdev_priv(netdev);

	ixgb_down(adapter, TRUE);

	ixgb_free_tx_resources(adapter);
	ixgb_free_rx_resources(adapter);

	return 0;
}

/**
 * ixgb_setup_tx_resources - allocate Tx resources (Descriptors)
 * @adapter: board private structure
 *
 * Return 0 on success, negative on failure
 **/

int
ixgb_setup_tx_resources(struct ixgb_adapter *adapter)
{
	struct ixgb_desc_ring *txdr = &adapter->tx_ring;
	struct pci_dev *pdev = adapter->pdev;
	int size;

	size = sizeof(struct ixgb_buffer) * txdr->count;
	txdr->buffer_info = vmalloc(size);
	if(!txdr->buffer_info) {
		DPRINTK(PROBE, ERR,
		 "Unable to allocate transmit descriptor ring memory\n");
		return -ENOMEM;
	}
	memset(txdr->buffer_info, 0, size);

	/* round up to nearest 4K */

	txdr->size = txdr->count * sizeof(struct ixgb_tx_desc);
	IXGB_ROUNDUP(txdr->size, 4096);

	txdr->desc = pci_alloc_consistent(pdev, txdr->size, &txdr->dma);
	if(!txdr->desc) {
		vfree(txdr->buffer_info);
		DPRINTK(PROBE, ERR,
		 "Unable to allocate transmit descriptor memory\n");
		return -ENOMEM;
	}
	memset(txdr->desc, 0, txdr->size);

	txdr->next_to_use = 0;
	txdr->next_to_clean = 0;

	return 0;
}

/**
 * ixgb_configure_tx - Configure 82597 Transmit Unit after Reset.
 * @adapter: board private structure
 *
 * Configure the Tx unit of the MAC after a reset.
 **/

static void
ixgb_configure_tx(struct ixgb_adapter *adapter)
{
	uint64_t tdba = adapter->tx_ring.dma;
	uint32_t tdlen = adapter->tx_ring.count * sizeof(struct ixgb_tx_desc);
	uint32_t tctl;
	struct ixgb_hw *hw = &adapter->hw;

	/* Setup the Base and Length of the Tx Descriptor Ring 
	 * tx_ring.dma can be either a 32 or 64 bit value 
	 */

	IXGB_WRITE_REG(hw, TDBAL, (tdba & 0x00000000ffffffffULL));
	IXGB_WRITE_REG(hw, TDBAH, (tdba >> 32));

	IXGB_WRITE_REG(hw, TDLEN, tdlen);

	/* Setup the HW Tx Head and Tail descriptor pointers */

	IXGB_WRITE_REG(hw, TDH, 0);
	IXGB_WRITE_REG(hw, TDT, 0);

	/* don't set up txdctl, it induces performance problems if configured
	 * incorrectly */
	/* Set the Tx Interrupt Delay register */

	IXGB_WRITE_REG(hw, TIDV, adapter->tx_int_delay);

	/* Program the Transmit Control Register */

	tctl = IXGB_TCTL_TCE | IXGB_TCTL_TXEN | IXGB_TCTL_TPDE;
	IXGB_WRITE_REG(hw, TCTL, tctl);

	/* Setup Transmit Descriptor Settings for this adapter */
	adapter->tx_cmd_type =
		IXGB_TX_DESC_TYPE 
		| (adapter->tx_int_delay_enable ? IXGB_TX_DESC_CMD_IDE : 0);
}

/**
 * ixgb_setup_rx_resources - allocate Rx resources (Descriptors)
 * @adapter: board private structure
 *
 * Returns 0 on success, negative on failure
 **/

int
ixgb_setup_rx_resources(struct ixgb_adapter *adapter)
{
	struct ixgb_desc_ring *rxdr = &adapter->rx_ring;
	struct pci_dev *pdev = adapter->pdev;
	int size;

	size = sizeof(struct ixgb_buffer) * rxdr->count;
	rxdr->buffer_info = vmalloc(size);
	if(!rxdr->buffer_info) {
		DPRINTK(PROBE, ERR,
		 "Unable to allocate receive descriptor ring\n");
		return -ENOMEM;
	}
	memset(rxdr->buffer_info, 0, size);

	/* Round up to nearest 4K */

	rxdr->size = rxdr->count * sizeof(struct ixgb_rx_desc);
	IXGB_ROUNDUP(rxdr->size, 4096);

	rxdr->desc = pci_alloc_consistent(pdev, rxdr->size, &rxdr->dma);

	if(!rxdr->desc) {
		vfree(rxdr->buffer_info);
		DPRINTK(PROBE, ERR,
		 "Unable to allocate receive descriptors\n");
		return -ENOMEM;
	}
	memset(rxdr->desc, 0, rxdr->size);

	rxdr->next_to_clean = 0;
	rxdr->next_to_use = 0;

	return 0;
}

/**
 * ixgb_setup_rctl - configure the receive control register
 * @adapter: Board private structure
 **/

static void
ixgb_setup_rctl(struct ixgb_adapter *adapter)
{
	uint32_t rctl;

	rctl = IXGB_READ_REG(&adapter->hw, RCTL);

	rctl &= ~(3 << IXGB_RCTL_MO_SHIFT);

	rctl |=
		IXGB_RCTL_BAM | IXGB_RCTL_RDMTS_1_2 | 
		IXGB_RCTL_RXEN | IXGB_RCTL_CFF | 
		(adapter->hw.mc_filter_type << IXGB_RCTL_MO_SHIFT);

	rctl |= IXGB_RCTL_SECRC;

	if (adapter->rx_buffer_len <= IXGB_RXBUFFER_2048)
		rctl |= IXGB_RCTL_BSIZE_2048;
	else if (adapter->rx_buffer_len <= IXGB_RXBUFFER_4096)
		rctl |= IXGB_RCTL_BSIZE_4096;
	else if (adapter->rx_buffer_len <= IXGB_RXBUFFER_8192)
		rctl |= IXGB_RCTL_BSIZE_8192;
	else if (adapter->rx_buffer_len <= IXGB_RXBUFFER_16384)
		rctl |= IXGB_RCTL_BSIZE_16384;

	IXGB_WRITE_REG(&adapter->hw, RCTL, rctl);
}

/**
 * ixgb_configure_rx - Configure 82597 Receive Unit after Reset.
 * @adapter: board private structure
 *
 * Configure the Rx unit of the MAC after a reset.
 **/

static void
ixgb_configure_rx(struct ixgb_adapter *adapter)
{
	uint64_t rdba = adapter->rx_ring.dma;
	uint32_t rdlen = adapter->rx_ring.count * sizeof(struct ixgb_rx_desc);
	struct ixgb_hw *hw = &adapter->hw;
	uint32_t rctl;
	uint32_t rxcsum;
	uint32_t rxdctl;

	/* make sure receives are disabled while setting up the descriptors */

	rctl = IXGB_READ_REG(hw, RCTL);
	IXGB_WRITE_REG(hw, RCTL, rctl & ~IXGB_RCTL_RXEN);

	/* set the Receive Delay Timer Register */

	IXGB_WRITE_REG(hw, RDTR, adapter->rx_int_delay);

	/* Setup the Base and Length of the Rx Descriptor Ring */

	IXGB_WRITE_REG(hw, RDBAL, (rdba & 0x00000000ffffffffULL));
	IXGB_WRITE_REG(hw, RDBAH, (rdba >> 32));

	IXGB_WRITE_REG(hw, RDLEN, rdlen);

	/* Setup the HW Rx Head and Tail Descriptor Pointers */
	IXGB_WRITE_REG(hw, RDH, 0);
	IXGB_WRITE_REG(hw, RDT, 0);

	/* set up pre-fetching of receive buffers so we get some before we
	 * run out (default hardware behavior is to run out before fetching
	 * more).  This sets up to fetch if HTHRESH rx descriptors are avail
	 * and the descriptors in hw cache are below PTHRESH.  This avoids
	 * the hardware behavior of fetching <=512 descriptors in a single
	 * burst that pre-empts all other activity, usually causing fifo
	 * overflows. */
	/* use WTHRESH to burst write 16 descriptors or burst when RXT0 */
	rxdctl = RXDCTL_WTHRESH_DEFAULT << IXGB_RXDCTL_WTHRESH_SHIFT |
	         RXDCTL_HTHRESH_DEFAULT << IXGB_RXDCTL_HTHRESH_SHIFT |
	         RXDCTL_PTHRESH_DEFAULT << IXGB_RXDCTL_PTHRESH_SHIFT;
	IXGB_WRITE_REG(hw, RXDCTL, rxdctl);

	/* Enable Receive Checksum Offload for TCP and UDP */
	if(adapter->rx_csum == TRUE) {
		rxcsum = IXGB_READ_REG(hw, RXCSUM);
		rxcsum |= IXGB_RXCSUM_TUOFL;
		IXGB_WRITE_REG(hw, RXCSUM, rxcsum);
	}

	/* Enable Receives */

	IXGB_WRITE_REG(hw, RCTL, rctl);
}

/**
 * ixgb_free_tx_resources - Free Tx Resources
 * @adapter: board private structure
 *
 * Free all transmit software resources
 **/

void
ixgb_free_tx_resources(struct ixgb_adapter *adapter)
{
	struct pci_dev *pdev = adapter->pdev;

	ixgb_clean_tx_ring(adapter);

	vfree(adapter->tx_ring.buffer_info);
	adapter->tx_ring.buffer_info = NULL;

	pci_free_consistent(pdev, adapter->tx_ring.size,
			    adapter->tx_ring.desc, adapter->tx_ring.dma);

	adapter->tx_ring.desc = NULL;
}

static void
ixgb_unmap_and_free_tx_resource(struct ixgb_adapter *adapter,
					struct ixgb_buffer *buffer_info)
{
	struct pci_dev *pdev = adapter->pdev;

	if (buffer_info->dma)
		pci_unmap_page(pdev, buffer_info->dma, buffer_info->length,
		               PCI_DMA_TODEVICE);

	if (buffer_info->skb)
		dev_kfree_skb_any(buffer_info->skb);

	buffer_info->skb = NULL;
	buffer_info->dma = 0;
	buffer_info->time_stamp = 0;
	/* these fields must always be initialized in tx
	 * buffer_info->length = 0;
	 * buffer_info->next_to_watch = 0; */
}

/**
 * ixgb_clean_tx_ring - Free Tx Buffers
 * @adapter: board private structure
 **/

static void
ixgb_clean_tx_ring(struct ixgb_adapter *adapter)
{
	struct ixgb_desc_ring *tx_ring = &adapter->tx_ring;
	struct ixgb_buffer *buffer_info;
	unsigned long size;
	unsigned int i;

	/* Free all the Tx ring sk_buffs */

	for(i = 0; i < tx_ring->count; i++) {
		buffer_info = &tx_ring->buffer_info[i];
		ixgb_unmap_and_free_tx_resource(adapter, buffer_info);
	}

	size = sizeof(struct ixgb_buffer) * tx_ring->count;
	memset(tx_ring->buffer_info, 0, size);

	/* Zero out the descriptor ring */

	memset(tx_ring->desc, 0, tx_ring->size);

	tx_ring->next_to_use = 0;
	tx_ring->next_to_clean = 0;

	IXGB_WRITE_REG(&adapter->hw, TDH, 0);
	IXGB_WRITE_REG(&adapter->hw, TDT, 0);
}

/**
 * ixgb_free_rx_resources - Free Rx Resources
 * @adapter: board private structure
 *
 * Free all receive software resources
 **/

void
ixgb_free_rx_resources(struct ixgb_adapter *adapter)
{
	struct ixgb_desc_ring *rx_ring = &adapter->rx_ring;
	struct pci_dev *pdev = adapter->pdev;

	ixgb_clean_rx_ring(adapter);

	vfree(rx_ring->buffer_info);
	rx_ring->buffer_info = NULL;

	pci_free_consistent(pdev, rx_ring->size, rx_ring->desc, rx_ring->dma);

	rx_ring->desc = NULL;
}

/**
 * ixgb_clean_rx_ring - Free Rx Buffers
 * @adapter: board private structure
 **/

static void
ixgb_clean_rx_ring(struct ixgb_adapter *adapter)
{
	struct ixgb_desc_ring *rx_ring = &adapter->rx_ring;
	struct ixgb_buffer *buffer_info;
	struct pci_dev *pdev = adapter->pdev;
	unsigned long size;
	unsigned int i;

	/* Free all the Rx ring sk_buffs */

	for(i = 0; i < rx_ring->count; i++) {
		buffer_info = &rx_ring->buffer_info[i];
		if(buffer_info->skb) {

			pci_unmap_single(pdev,
					 buffer_info->dma,
					 buffer_info->length,
					 PCI_DMA_FROMDEVICE);

			dev_kfree_skb(buffer_info->skb);

			buffer_info->skb = NULL;
		}
	}

	size = sizeof(struct ixgb_buffer) * rx_ring->count;
	memset(rx_ring->buffer_info, 0, size);

	/* Zero out the descriptor ring */

	memset(rx_ring->desc, 0, rx_ring->size);

	rx_ring->next_to_clean = 0;
	rx_ring->next_to_use = 0;

	IXGB_WRITE_REG(&adapter->hw, RDH, 0);
	IXGB_WRITE_REG(&adapter->hw, RDT, 0);
}

/**
 * ixgb_set_mac - Change the Ethernet Address of the NIC
 * @netdev: network interface device structure
 * @p: pointer to an address structure
 *
 * Returns 0 on success, negative on failure
 **/

static int
ixgb_set_mac(struct net_device *netdev, void *p)
{
	struct ixgb_adapter *adapter = netdev_priv(netdev);
	struct sockaddr *addr = p;

	if(!is_valid_ether_addr(addr->sa_data))
		return -EADDRNOTAVAIL;

	memcpy(netdev->dev_addr, addr->sa_data, netdev->addr_len);

	ixgb_rar_set(&adapter->hw, addr->sa_data, 0);

	return 0;
}

/**
 * ixgb_set_multi - Multicast and Promiscuous mode set
 * @netdev: network interface device structure
 *
 * The set_multi entry point is called whenever the multicast address
 * list or the network interface flags are updated.  This routine is
 * responsible for configuring the hardware for proper multicast,
 * promiscuous mode, and all-multi behavior.
 **/

static void
ixgb_set_multi(struct net_device *netdev)
{
	struct ixgb_adapter *adapter = netdev_priv(netdev);
	struct ixgb_hw *hw = &adapter->hw;
	struct dev_mc_list *mc_ptr;
	uint32_t rctl;
	int i;

	/* Check for Promiscuous and All Multicast modes */

	rctl = IXGB_READ_REG(hw, RCTL);

	if(netdev->flags & IFF_PROMISC) {
		rctl |= (IXGB_RCTL_UPE | IXGB_RCTL_MPE);
	} else if(netdev->flags & IFF_ALLMULTI) {
		rctl |= IXGB_RCTL_MPE;
		rctl &= ~IXGB_RCTL_UPE;
	} else {
		rctl &= ~(IXGB_RCTL_UPE | IXGB_RCTL_MPE);
	}

	if(netdev->mc_count > IXGB_MAX_NUM_MULTICAST_ADDRESSES) {
		rctl |= IXGB_RCTL_MPE;
		IXGB_WRITE_REG(hw, RCTL, rctl);
	} else {
		uint8_t mta[netdev->mc_count * IXGB_ETH_LENGTH_OF_ADDRESS];

		IXGB_WRITE_REG(hw, RCTL, rctl);

		for(i = 0, mc_ptr = netdev->mc_list; mc_ptr;
			i++, mc_ptr = mc_ptr->next)
			memcpy(&mta[i * IXGB_ETH_LENGTH_OF_ADDRESS],
				   mc_ptr->dmi_addr, IXGB_ETH_LENGTH_OF_ADDRESS);

		ixgb_mc_addr_list_update(hw, mta, netdev->mc_count, 0);
	}
}

/**
 * ixgb_watchdog - Timer Call-back
 * @data: pointer to netdev cast into an unsigned long
 **/

static void
ixgb_watchdog(unsigned long data)
{
	struct ixgb_adapter *adapter = (struct ixgb_adapter *)data;
	struct net_device *netdev = adapter->netdev;
	struct ixgb_desc_ring *txdr = &adapter->tx_ring;

	ixgb_check_for_link(&adapter->hw);

	if (ixgb_check_for_bad_link(&adapter->hw)) {
		/* force the reset path */
		netif_stop_queue(netdev);
	}

	if(adapter->hw.link_up) {
		if(!netif_carrier_ok(netdev)) {
			DPRINTK(LINK, INFO,
			        "NIC Link is Up 10000 Mbps Full Duplex\n");
			adapter->link_speed = 10000;
			adapter->link_duplex = FULL_DUPLEX;
			netif_carrier_on(netdev);
			netif_wake_queue(netdev);
		}
	} else {
		if(netif_carrier_ok(netdev)) {
			adapter->link_speed = 0;
			adapter->link_duplex = 0;
			DPRINTK(LINK, INFO, "NIC Link is Down\n");
			netif_carrier_off(netdev);
			netif_stop_queue(netdev);

		}
	}

	ixgb_update_stats(adapter);

	if(!netif_carrier_ok(netdev)) {
		if(IXGB_DESC_UNUSED(txdr) + 1 < txdr->count) {
			/* We've lost link, so the controller stops DMA,
			 * but we've got queued Tx work that's never going
			 * to get done, so reset controller to flush Tx.
			 * (Do the reset outside of interrupt context). */
			schedule_work(&adapter->tx_timeout_task);
		}
	}

	/* Force detection of hung controller every watchdog period */
	adapter->detect_tx_hung = TRUE;

	/* generate an interrupt to force clean up of any stragglers */
	IXGB_WRITE_REG(&adapter->hw, ICS, IXGB_INT_TXDW);

	/* Reset the timer */
	mod_timer(&adapter->watchdog_timer, jiffies + 2 * HZ);
}

#define IXGB_TX_FLAGS_CSUM		0x00000001
#define IXGB_TX_FLAGS_VLAN		0x00000002
#define IXGB_TX_FLAGS_TSO		0x00000004

static int
ixgb_tso(struct ixgb_adapter *adapter, struct sk_buff *skb)
{
#ifdef NETIF_F_TSO
	struct ixgb_context_desc *context_desc;
	unsigned int i;
	uint8_t ipcss, ipcso, tucss, tucso, hdr_len;
	uint16_t ipcse, tucse, mss;
	int err;

	if (likely(skb_is_gso(skb))) {
		if (skb_header_cloned(skb)) {
			err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
			if (err)
				return err;
		}

		hdr_len = ((skb->h.raw - skb->data) + (skb->h.th->doff << 2));
		mss = skb_shinfo(skb)->gso_size;
		skb->nh.iph->tot_len = 0;
		skb->nh.iph->check = 0;
		skb->h.th->check = ~csum_tcpudp_magic(skb->nh.iph->saddr,
						      skb->nh.iph->daddr,
						      0, IPPROTO_TCP, 0);
		ipcss = skb->nh.raw - skb->data;
		ipcso = (void *)&(skb->nh.iph->check) - (void *)skb->data;
		ipcse = skb->h.raw - skb->data - 1;
		tucss = skb->h.raw - skb->data;
		tucso = (void *)&(skb->h.th->check) - (void *)skb->data;
		tucse = 0;

		i = adapter->tx_ring.next_to_use;
		context_desc = IXGB_CONTEXT_DESC(adapter->tx_ring, i);

		context_desc->ipcss = ipcss;
		context_desc->ipcso = ipcso;
		context_desc->ipcse = cpu_to_le16(ipcse);
		context_desc->tucss = tucss;
		context_desc->tucso = tucso;
		context_desc->tucse = cpu_to_le16(tucse);
		context_desc->mss = cpu_to_le16(mss);
		context_desc->hdr_len = hdr_len;
		context_desc->status = 0;
		context_desc->cmd_type_len = cpu_to_le32(
						  IXGB_CONTEXT_DESC_TYPE 
						| IXGB_CONTEXT_DESC_CMD_TSE
						| IXGB_CONTEXT_DESC_CMD_IP
						| IXGB_CONTEXT_DESC_CMD_TCP
						| IXGB_CONTEXT_DESC_CMD_IDE
						| (skb->len - (hdr_len)));


		if(++i == adapter->tx_ring.count) i = 0;
		adapter->tx_ring.next_to_use = i;

		return 1;
	}
#endif

	return 0;
}

static boolean_t
ixgb_tx_csum(struct ixgb_adapter *adapter, struct sk_buff *skb)
{
	struct ixgb_context_desc *context_desc;
	unsigned int i;
	uint8_t css, cso;

	if(likely(skb->ip_summed == CHECKSUM_HW)) {
		css = skb->h.raw - skb->data;
		cso = (skb->h.raw + skb->csum) - skb->data;

		i = adapter->tx_ring.next_to_use;
		context_desc = IXGB_CONTEXT_DESC(adapter->tx_ring, i);

		context_desc->tucss = css;
		context_desc->tucso = cso;
		context_desc->tucse = 0;
		/* zero out any previously existing data in one instruction */
		*(uint32_t *)&(context_desc->ipcss) = 0;
		context_desc->status = 0;
		context_desc->hdr_len = 0;
		context_desc->mss = 0;
		context_desc->cmd_type_len =
			cpu_to_le32(IXGB_CONTEXT_DESC_TYPE
				    | IXGB_TX_DESC_CMD_IDE);

		if(++i == adapter->tx_ring.count) i = 0;
		adapter->tx_ring.next_to_use = i;

		return TRUE;
	}

	return FALSE;
}

#define IXGB_MAX_TXD_PWR	14
#define IXGB_MAX_DATA_PER_TXD	(1<<IXGB_MAX_TXD_PWR)

static int
ixgb_tx_map(struct ixgb_adapter *adapter, struct sk_buff *skb,
	    unsigned int first)
{
	struct ixgb_desc_ring *tx_ring = &adapter->tx_ring;
	struct ixgb_buffer *buffer_info;
	int len = skb->len;
	unsigned int offset = 0, size, count = 0, i;

	unsigned int nr_frags = skb_shinfo(skb)->nr_frags;
	unsigned int f;

	len -= skb->data_len;

	i = tx_ring->next_to_use;

	while(len) {
		buffer_info = &tx_ring->buffer_info[i];
		size = min(len, IXGB_MAX_DATA_PER_TXD);
		buffer_info->length = size;
		buffer_info->dma =
			pci_map_single(adapter->pdev,
				skb->data + offset,
				size,
				PCI_DMA_TODEVICE);
		buffer_info->time_stamp = jiffies;
		buffer_info->next_to_watch = 0;

		len -= size;
		offset += size;
		count++;
		if(++i == tx_ring->count) i = 0;
	}

	for(f = 0; f < nr_frags; f++) {
		struct skb_frag_struct *frag;

		frag = &skb_shinfo(skb)->frags[f];
		len = frag->size;
		offset = 0;

		while(len) {
			buffer_info = &tx_ring->buffer_info[i];
			size = min(len, IXGB_MAX_DATA_PER_TXD);
			buffer_info->length = size;
			buffer_info->dma =
				pci_map_page(adapter->pdev,
					frag->page,
					frag->page_offset + offset,
					size,
					PCI_DMA_TODEVICE);
			buffer_info->time_stamp = jiffies;
			buffer_info->next_to_watch = 0;

			len -= size;
			offset += size;
			count++;
			if(++i == tx_ring->count) i = 0;
		}
	}
	i = (i == 0) ? tx_ring->count - 1 : i - 1;
	tx_ring->buffer_info[i].skb = skb;
	tx_ring->buffer_info[first].next_to_watch = i;

	return count;
}

static void
ixgb_tx_queue(struct ixgb_adapter *adapter, int count, int vlan_id,int tx_flags)
{
	struct ixgb_desc_ring *tx_ring = &adapter->tx_ring;
	struct ixgb_tx_desc *tx_desc = NULL;
	struct ixgb_buffer *buffer_info;
	uint32_t cmd_type_len = adapter->tx_cmd_type;
	uint8_t status = 0;
	uint8_t popts = 0;
	unsigned int i;

	if(tx_flags & IXGB_TX_FLAGS_TSO) {
		cmd_type_len |= IXGB_TX_DESC_CMD_TSE;
		popts |= (IXGB_TX_DESC_POPTS_IXSM | IXGB_TX_DESC_POPTS_TXSM);
	}

	if(tx_flags & IXGB_TX_FLAGS_CSUM)
		popts |= IXGB_TX_DESC_POPTS_TXSM;

	if(tx_flags & IXGB_TX_FLAGS_VLAN) {
		cmd_type_len |= IXGB_TX_DESC_CMD_VLE;
	}

	i = tx_ring->next_to_use;

	while(count--) {
		buffer_info = &tx_ring->buffer_info[i];
		tx_desc = IXGB_TX_DESC(*tx_ring, i);
		tx_desc->buff_addr = cpu_to_le64(buffer_info->dma);
		tx_desc->cmd_type_len =
			cpu_to_le32(cmd_type_len | buffer_info->length);
		tx_desc->status = status;
		tx_desc->popts = popts;
		tx_desc->vlan = cpu_to_le16(vlan_id);

		if(++i == tx_ring->count) i = 0;
	}

	tx_desc->cmd_type_len |= cpu_to_le32(IXGB_TX_DESC_CMD_EOP 
				| IXGB_TX_DESC_CMD_RS );

	/* Force memory writes to complete before letting h/w
	 * know there are new descriptors to fetch.  (Only
	 * applicable for weak-ordered memory model archs,
	 * such as IA-64). */
	wmb();

	tx_ring->next_to_use = i;
	IXGB_WRITE_REG(&adapter->hw, TDT, i);
}

/* Tx Descriptors needed, worst case */
#define TXD_USE_COUNT(S) (((S) >> IXGB_MAX_TXD_PWR) + \
			 (((S) & (IXGB_MAX_DATA_PER_TXD - 1)) ? 1 : 0))
#define DESC_NEEDED TXD_USE_COUNT(IXGB_MAX_DATA_PER_TXD) + \
	MAX_SKB_FRAGS * TXD_USE_COUNT(PAGE_SIZE) + 1

static int
ixgb_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
{
	struct ixgb_adapter *adapter = netdev_priv(netdev);
	unsigned int first;
	unsigned int tx_flags = 0;
	unsigned long flags;
	int vlan_id = 0;
	int tso;

	if(skb->len <= 0) {
		dev_kfree_skb_any(skb);
		return 0;
	}

#ifdef NETIF_F_LLTX
	local_irq_save(flags);
	if (!spin_trylock(&adapter->tx_lock)) {
		/* Collision - tell upper layer to requeue */
		local_irq_restore(flags);
		return NETDEV_TX_LOCKED;
	}
#else
	spin_lock_irqsave(&adapter->tx_lock, flags);
#endif

	if(unlikely(IXGB_DESC_UNUSED(&adapter->tx_ring) < DESC_NEEDED)) {
		netif_stop_queue(netdev);
		spin_unlock_irqrestore(&adapter->tx_lock, flags);
		return NETDEV_TX_BUSY;
	}

#ifndef NETIF_F_LLTX
	spin_unlock_irqrestore(&adapter->tx_lock, flags);
#endif

	if(adapter->vlgrp && vlan_tx_tag_present(skb)) {
		tx_flags |= IXGB_TX_FLAGS_VLAN;
		vlan_id = vlan_tx_tag_get(skb);
	}

	first = adapter->tx_ring.next_to_use;
	
	tso = ixgb_tso(adapter, skb);
	if (tso < 0) {
		dev_kfree_skb_any(skb);
#ifdef NETIF_F_LLTX
		spin_unlock_irqrestore(&adapter->tx_lock, flags);
#endif
		return NETDEV_TX_OK;
	}

	if (likely(tso))
		tx_flags |= IXGB_TX_FLAGS_TSO;
	else if(ixgb_tx_csum(adapter, skb))
		tx_flags |= IXGB_TX_FLAGS_CSUM;

	ixgb_tx_queue(adapter, ixgb_tx_map(adapter, skb, first), vlan_id,
			tx_flags);

	netdev->trans_start = jiffies;

#ifdef NETIF_F_LLTX
	/* Make sure there is space in the ring for the next send. */
	if(unlikely(IXGB_DESC_UNUSED(&adapter->tx_ring) < DESC_NEEDED))
		netif_stop_queue(netdev);

	spin_unlock_irqrestore(&adapter->tx_lock, flags);

#endif
	return NETDEV_TX_OK;
}

/**
 * ixgb_tx_timeout - Respond to a Tx Hang
 * @netdev: network interface device structure
 **/

static void
ixgb_tx_timeout(struct net_device *netdev)
{
	struct ixgb_adapter *adapter = netdev_priv(netdev);

	/* Do the reset outside of interrupt context */
	schedule_work(&adapter->tx_timeout_task);
}

static void
ixgb_tx_timeout_task(struct net_device *netdev)
{
	struct ixgb_adapter *adapter = netdev_priv(netdev);

	adapter->tx_timeout_count++;
	ixgb_down(adapter, TRUE);
	ixgb_up(adapter);
}

/**
 * ixgb_get_stats - Get System Network Statistics
 * @netdev: network interface device structure
 *
 * Returns the address of the device statistics structure.
 * The statistics are actually updated from the timer callback.
 **/

static struct net_device_stats *
ixgb_get_stats(struct net_device *netdev)
{
	struct ixgb_adapter *adapter = netdev_priv(netdev);

	return &adapter->net_stats;
}

/**
 * ixgb_change_mtu - Change the Maximum Transfer Unit
 * @netdev: network interface device structure
 * @new_mtu: new value for maximum frame size
 *
 * Returns 0 on success, negative on failure
 **/

static int
ixgb_change_mtu(struct net_device *netdev, int new_mtu)
{
	struct ixgb_adapter *adapter = netdev_priv(netdev);
	int max_frame = new_mtu + ENET_HEADER_SIZE + ENET_FCS_LENGTH;
	int old_max_frame = netdev->mtu + ENET_HEADER_SIZE + ENET_FCS_LENGTH;


	if((max_frame < IXGB_MIN_ENET_FRAME_SIZE_WITHOUT_FCS + ENET_FCS_LENGTH)
	   || (max_frame > IXGB_MAX_JUMBO_FRAME_SIZE + ENET_FCS_LENGTH)) {
		DPRINTK(PROBE, ERR, "Invalid MTU setting %d\n", new_mtu);
		return -EINVAL;
	}

	adapter->rx_buffer_len = max_frame;

	netdev->mtu = new_mtu;

	if ((old_max_frame != max_frame) && netif_running(netdev)) {
		ixgb_down(adapter, TRUE);
		ixgb_up(adapter);
	}

	return 0;
}

/**
 * ixgb_update_stats - Update the board statistics counters.
 * @adapter: board private structure
 **/

void
ixgb_update_stats(struct ixgb_adapter *adapter)
{
	struct net_device *netdev = adapter->netdev;

	if((netdev->flags & IFF_PROMISC) || (netdev->flags & IFF_ALLMULTI) ||
	   (netdev->mc_count > IXGB_MAX_NUM_MULTICAST_ADDRESSES)) {
		u64 multi = IXGB_READ_REG(&adapter->hw, MPRCL);
		u32 bcast_l = IXGB_READ_REG(&adapter->hw, BPRCL);
		u32 bcast_h = IXGB_READ_REG(&adapter->hw, BPRCH);
		u64 bcast = ((u64)bcast_h << 32) | bcast_l; 

		multi |= ((u64)IXGB_READ_REG(&adapter->hw, MPRCH) << 32);
		/* fix up multicast stats by removing broadcasts */
		if(multi >= bcast)
			multi -= bcast;
		
		adapter->stats.mprcl += (multi & 0xFFFFFFFF);
		adapter->stats.mprch += (multi >> 32);
		adapter->stats.bprcl += bcast_l; 
		adapter->stats.bprch += bcast_h;
	} else {
		adapter->stats.mprcl += IXGB_READ_REG(&adapter->hw, MPRCL);
		adapter->stats.mprch += IXGB_READ_REG(&adapter->hw, MPRCH);
		adapter->stats.bprcl += IXGB_READ_REG(&adapter->hw, BPRCL);
		adapter->stats.bprch += IXGB_READ_REG(&adapter->hw, BPRCH);
	}
	adapter->stats.tprl += IXGB_READ_REG(&adapter->hw, TPRL);
	adapter->stats.tprh += IXGB_READ_REG(&adapter->hw, TPRH);
	adapter->stats.gprcl += IXGB_READ_REG(&adapter->hw, GPRCL);
	adapter->stats.gprch += IXGB_READ_REG(&adapter->hw, GPRCH);
	adapter->stats.uprcl += IXGB_READ_REG(&adapter->hw, UPRCL);
	adapter->stats.uprch += IXGB_READ_REG(&adapter->hw, UPRCH);
	adapter->stats.vprcl += IXGB_READ_REG(&adapter->hw, VPRCL);
	adapter->stats.vprch += IXGB_READ_REG(&adapter->hw, VPRCH);
	adapter->stats.jprcl += IXGB_READ_REG(&adapter->hw, JPRCL);
	adapter->stats.jprch += IXGB_READ_REG(&adapter->hw, JPRCH);
	adapter->stats.gorcl += IXGB_READ_REG(&adapter->hw, GORCL);
	adapter->stats.gorch += IXGB_READ_REG(&adapter->hw, GORCH);
	adapter->stats.torl += IXGB_READ_REG(&adapter->hw, TORL);
	adapter->stats.torh += IXGB_READ_REG(&adapter->hw, TORH);
	adapter->stats.rnbc += IXGB_READ_REG(&adapter->hw, RNBC);
	adapter->stats.ruc += IXGB_READ_REG(&adapter->hw, RUC);
	adapter->stats.roc += IXGB_READ_REG(&adapter->hw, ROC);
	adapter->stats.rlec += IXGB_READ_REG(&adapter->hw, RLEC);
	adapter->stats.crcerrs += IXGB_READ_REG(&adapter->hw, CRCERRS);
	adapter->stats.icbc += IXGB_READ_REG(&adapter->hw, ICBC);
	adapter->stats.ecbc += IXGB_READ_REG(&adapter->hw, ECBC);
	adapter->stats.mpc += IXGB_READ_REG(&adapter->hw, MPC);
	adapter->stats.tptl += IXGB_READ_REG(&adapter->hw, TPTL);
	adapter->stats.tpth += IXGB_READ_REG(&adapter->hw, TPTH);
	adapter->stats.gptcl += IXGB_READ_REG(&adapter->hw, GPTCL);
	adapter->stats.gptch += IXGB_READ_REG(&adapter->hw, GPTCH);
	adapter->stats.bptcl += IXGB_READ_REG(&adapter->hw, BPTCL);
	adapter->stats.bptch += IXGB_READ_REG(&adapter->hw, BPTCH);
	adapter->stats.mptcl += IXGB_READ_REG(&adapter->hw, MPTCL);
	adapter->stats.mptch += IXGB_READ_REG(&adapter->hw, MPTCH);
	adapter->stats.uptcl += IXGB_READ_REG(&adapter->hw, UPTCL);
	adapter->stats.uptch += IXGB_READ_REG(&adapter->hw, UPTCH);
	adapter->stats.vptcl += IXGB_READ_REG(&adapter->hw, VPTCL);
	adapter->stats.vptch += IXGB_READ_REG(&adapter->hw, VPTCH);
	adapter->stats.jptcl += IXGB_READ_REG(&adapter->hw, JPTCL);
	adapter->stats.jptch += IXGB_READ_REG(&adapter->hw, JPTCH);
	adapter->stats.gotcl += IXGB_READ_REG(&adapter->hw, GOTCL);
	adapter->stats.gotch += IXGB_READ_REG(&adapter->hw, GOTCH);
	adapter->stats.totl += IXGB_READ_REG(&adapter->hw, TOTL);
	adapter->stats.toth += IXGB_READ_REG(&adapter->hw, TOTH);
	adapter->stats.dc += IXGB_READ_REG(&adapter->hw, DC);
	adapter->stats.plt64c += IXGB_READ_REG(&adapter->hw, PLT64C);
	adapter->stats.tsctc += IXGB_READ_REG(&adapter->hw, TSCTC);
	adapter->stats.tsctfc += IXGB_READ_REG(&adapter->hw, TSCTFC);
	adapter->stats.ibic += IXGB_READ_REG(&adapter->hw, IBIC);
	adapter->stats.rfc += IXGB_READ_REG(&adapter->hw, RFC);
	adapter->stats.lfc += IXGB_READ_REG(&adapter->hw, LFC);
	adapter->stats.pfrc += IXGB_READ_REG(&adapter->hw, PFRC);
	adapter->stats.pftc += IXGB_READ_REG(&adapter->hw, PFTC);
	adapter->stats.mcfrc += IXGB_READ_REG(&adapter->hw, MCFRC);
	adapter->stats.mcftc += IXGB_READ_REG(&adapter->hw, MCFTC);
	adapter->stats.xonrxc += IXGB_READ_REG(&adapter->hw, XONRXC);
	adapter->stats.xontxc += IXGB_READ_REG(&adapter->hw, XONTXC);
	adapter->stats.xoffrxc += IXGB_READ_REG(&adapter->hw, XOFFRXC);
	adapter->stats.xofftxc += IXGB_READ_REG(&adapter->hw, XOFFTXC);
	adapter->stats.rjc += IXGB_READ_REG(&adapter->hw, RJC);

	/* Fill out the OS statistics structure */

	adapter->net_stats.rx_packets = adapter->stats.gprcl;
	adapter->net_stats.tx_packets = adapter->stats.gptcl;
	adapter->net_stats.rx_bytes = adapter->stats.gorcl;
	adapter->net_stats.tx_bytes = adapter->stats.gotcl;
	adapter->net_stats.multicast = adapter->stats.mprcl;
	adapter->net_stats.collisions = 0;

	/* ignore RLEC as it reports errors for padded (<64bytes) frames
	 * with a length in the type/len field */
	adapter->net_stats.rx_errors =
	    /* adapter->stats.rnbc + */ adapter->stats.crcerrs +
	    adapter->stats.ruc +
	    adapter->stats.roc /*+ adapter->stats.rlec */  +
	    adapter->stats.icbc +
	    adapter->stats.ecbc + adapter->stats.mpc;

	/* see above
	 * adapter->net_stats.rx_length_errors = adapter->stats.rlec;
	 */

	adapter->net_stats.rx_crc_errors = adapter->stats.crcerrs;
	adapter->net_stats.rx_fifo_errors = adapter->stats.mpc;
	adapter->net_stats.rx_missed_errors = adapter->stats.mpc;
	adapter->net_stats.rx_over_errors = adapter->stats.mpc;

	adapter->net_stats.tx_errors = 0;
	adapter->net_stats.rx_frame_errors = 0;
	adapter->net_stats.tx_aborted_errors = 0;
	adapter->net_stats.tx_carrier_errors = 0;
	adapter->net_stats.tx_fifo_errors = 0;
	adapter->net_stats.tx_heartbeat_errors = 0;
	adapter->net_stats.tx_window_errors = 0;
}

#define IXGB_MAX_INTR 10
/**
 * ixgb_intr - Interrupt Handler
 * @irq: interrupt number
 * @data: pointer to a network interface device structure
 * @pt_regs: CPU registers structure
 **/

static irqreturn_t
ixgb_intr(int irq, void *data, struct pt_regs *regs)
{
	struct net_device *netdev = data;
	struct ixgb_adapter *adapter = netdev_priv(netdev);
	struct ixgb_hw *hw = &adapter->hw;
	uint32_t icr = IXGB_READ_REG(hw, ICR);
#ifndef CONFIG_IXGB_NAPI
	unsigned int i;
#endif

	if(unlikely(!icr))
		return IRQ_NONE;  /* Not our interrupt */

	if(unlikely(icr & (IXGB_INT_RXSEQ | IXGB_INT_LSC))) {
		mod_timer(&adapter->watchdog_timer, jiffies);
	}

#ifdef CONFIG_IXGB_NAPI
	if(netif_rx_schedule_prep(netdev)) {

		/* Disable interrupts and register for poll. The flush 
		  of the posted write is intentionally left out.
		*/

		atomic_inc(&adapter->irq_sem);
		IXGB_WRITE_REG(&adapter->hw, IMC, ~0);
		__netif_rx_schedule(netdev);
	}
#else
	/* yes, that is actually a & and it is meant to make sure that
	 * every pass through this for loop checks both receive and
	 * transmit queues for completed descriptors, intended to
	 * avoid starvation issues and assist tx/rx fairness. */
	for(i = 0; i < IXGB_MAX_INTR; i++)
		if(!ixgb_clean_rx_irq(adapter) &
		   !ixgb_clean_tx_irq(adapter))
			break;
#endif 
	return IRQ_HANDLED;
}

#ifdef CONFIG_IXGB_NAPI
/**
 * ixgb_clean - NAPI Rx polling callback
 * @adapter: board private structure
 **/

static int
ixgb_clean(struct net_device *netdev, int *budget)
{
	struct ixgb_adapter *adapter = netdev_priv(netdev);
	int work_to_do = min(*budget, netdev->quota);
	int tx_cleaned;
	int work_done = 0;

	tx_cleaned = ixgb_clean_tx_irq(adapter);
	ixgb_clean_rx_irq(adapter, &work_done, work_to_do);

	*budget -= work_done;
	netdev->quota -= work_done;

	/* if no Tx and not enough Rx work done, exit the polling mode */
	if((!tx_cleaned && (work_done == 0)) || !netif_running(netdev)) {
		netif_rx_complete(netdev);
		ixgb_irq_enable(adapter);
		return 0;
	}

	return 1;
}
#endif

/**
 * ixgb_clean_tx_irq - Reclaim resources after transmit completes
 * @adapter: board private structure
 **/

static boolean_t
ixgb_clean_tx_irq(struct ixgb_adapter *adapter)
{
	struct ixgb_desc_ring *tx_ring = &adapter->tx_ring;
	struct net_device *netdev = adapter->netdev;
	struct ixgb_tx_desc *tx_desc, *eop_desc;
	struct ixgb_buffer *buffer_info;
	unsigned int i, eop;
	boolean_t cleaned = FALSE;

	i = tx_ring->next_to_clean;
	eop = tx_ring->buffer_info[i].next_to_watch;
	eop_desc = IXGB_TX_DESC(*tx_ring, eop);

	while(eop_desc->status & IXGB_TX_DESC_STATUS_DD) {

		for(cleaned = FALSE; !cleaned; ) {
			tx_desc = IXGB_TX_DESC(*tx_ring, i);
			buffer_info = &tx_ring->buffer_info[i];

			if (tx_desc->popts
			    & (IXGB_TX_DESC_POPTS_TXSM |
			       IXGB_TX_DESC_POPTS_IXSM))
				adapter->hw_csum_tx_good++;

			ixgb_unmap_and_free_tx_resource(adapter, buffer_info);

			*(uint32_t *)&(tx_desc->status) = 0;

			cleaned = (i == eop);
			if(++i == tx_ring->count) i = 0;
		}

		eop = tx_ring->buffer_info[i].next_to_watch;
		eop_desc = IXGB_TX_DESC(*tx_ring, eop);
	}

	tx_ring->next_to_clean = i;

	if (unlikely(netif_queue_stopped(netdev))) {
		spin_lock(&adapter->tx_lock);
		if (netif_queue_stopped(netdev) && netif_carrier_ok(netdev) &&
		    (IXGB_DESC_UNUSED(tx_ring) > IXGB_TX_QUEUE_WAKE))
			netif_wake_queue(netdev);
		spin_unlock(&adapter->tx_lock);
	}

	if(adapter->detect_tx_hung) {
		/* detect a transmit hang in hardware, this serializes the
		 * check with the clearing of time_stamp and movement of i */
		adapter->detect_tx_hung = FALSE;
		if (tx_ring->buffer_info[eop].dma &&
		   time_after(jiffies, tx_ring->buffer_info[eop].time_stamp + HZ)
		   && !(IXGB_READ_REG(&adapter->hw, STATUS) &
		        IXGB_STATUS_TXOFF)) {
			/* detected Tx unit hang */
			DPRINTK(DRV, ERR, "Detected Tx Unit Hang\n"
					"  TDH                  <%x>\n"
					"  TDT                  <%x>\n"
					"  next_to_use          <%x>\n"
					"  next_to_clean        <%x>\n"
					"buffer_info[next_to_clean]\n"
					"  time_stamp           <%lx>\n"
					"  next_to_watch        <%x>\n"
					"  jiffies              <%lx>\n"
					"  next_to_watch.status <%x>\n",
				IXGB_READ_REG(&adapter->hw, TDH),
				IXGB_READ_REG(&adapter->hw, TDT),
				tx_ring->next_to_use,
				tx_ring->next_to_clean,
				tx_ring->buffer_info[eop].time_stamp,
				eop,
				jiffies,
				eop_desc->status);
			netif_stop_queue(netdev);
		}
	}

	return cleaned;
}

/**
 * ixgb_rx_checksum - Receive Checksum Offload for 82597.
 * @adapter: board private structure
 * @rx_desc: receive descriptor
 * @sk_buff: socket buffer with received data
 **/

static void
ixgb_rx_checksum(struct ixgb_adapter *adapter,
		 struct ixgb_rx_desc *rx_desc,
		 struct sk_buff *skb)
{
	/* Ignore Checksum bit is set OR
	 * TCP Checksum has not been calculated
	 */
	if((rx_desc->status & IXGB_RX_DESC_STATUS_IXSM) ||
	   (!(rx_desc->status & IXGB_RX_DESC_STATUS_TCPCS))) {
		skb->ip_summed = CHECKSUM_NONE;
		return;
	}

	/* At this point we know the hardware did the TCP checksum */
	/* now look at the TCP checksum error bit */
	if(rx_desc->errors & IXGB_RX_DESC_ERRORS_TCPE) {
		/* let the stack verify checksum errors */
		skb->ip_summed = CHECKSUM_NONE;
		adapter->hw_csum_rx_error++;
	} else {
		/* TCP checksum is good */
		skb->ip_summed = CHECKSUM_UNNECESSARY;
		adapter->hw_csum_rx_good++;
	}
}

/**
 * ixgb_clean_rx_irq - Send received data up the network stack,
 * @adapter: board private structure
 **/

static boolean_t
#ifdef CONFIG_IXGB_NAPI
ixgb_clean_rx_irq(struct ixgb_adapter *adapter, int *work_done, int work_to_do)
#else
ixgb_clean_rx_irq(struct ixgb_adapter *adapter)
#endif
{
	struct ixgb_desc_ring *rx_ring = &adapter->rx_ring;
	struct net_device *netdev = adapter->netdev;
	struct pci_dev *pdev = adapter->pdev;
	struct ixgb_rx_desc *rx_desc, *next_rxd;
	struct ixgb_buffer *buffer_info, *next_buffer, *next2_buffer;
	uint32_t length;
	unsigned int i, j;
	boolean_t cleaned = FALSE;

	i = rx_ring->next_to_clean;
	rx_desc = IXGB_RX_DESC(*rx_ring, i);
	buffer_info = &rx_ring->buffer_info[i];

	while(rx_desc->status & IXGB_RX_DESC_STATUS_DD) {
		struct sk_buff *skb, *next_skb;
		u8 status;

#ifdef CONFIG_IXGB_NAPI
		if(*work_done >= work_to_do)
			break;

		(*work_done)++;
#endif
		status = rx_desc->status;
		skb = buffer_info->skb;
		buffer_info->skb = NULL;

		prefetch(skb->data);

		if(++i == rx_ring->count) i = 0;
		next_rxd = IXGB_RX_DESC(*rx_ring, i);
		prefetch(next_rxd);

		if((j = i + 1) == rx_ring->count) j = 0;
		next2_buffer = &rx_ring->buffer_info[j];
		prefetch(next2_buffer);

		next_buffer = &rx_ring->buffer_info[i];
		next_skb = next_buffer->skb;
		prefetch(next_skb);

		cleaned = TRUE;

		pci_unmap_single(pdev,
				 buffer_info->dma,
				 buffer_info->length,
				 PCI_DMA_FROMDEVICE);

		length = le16_to_cpu(rx_desc->length);

		if(unlikely(!(status & IXGB_RX_DESC_STATUS_EOP))) {

			/* All receives must fit into a single buffer */

			IXGB_DBG("Receive packet consumed multiple buffers "
					 "length<%x>\n", length);

			dev_kfree_skb_irq(skb);
			goto rxdesc_done;
		}

		if (unlikely(rx_desc->errors
			     & (IXGB_RX_DESC_ERRORS_CE | IXGB_RX_DESC_ERRORS_SE
				| IXGB_RX_DESC_ERRORS_P |
				IXGB_RX_DESC_ERRORS_RXE))) {

			dev_kfree_skb_irq(skb);
			goto rxdesc_done;
		}

		/* code added for copybreak, this should improve
		 * performance for small packets with large amounts
		 * of reassembly being done in the stack */
#define IXGB_CB_LENGTH 256
		if (length < IXGB_CB_LENGTH) {
			struct sk_buff *new_skb =
			    dev_alloc_skb(length + NET_IP_ALIGN);
			if (new_skb) {
				skb_reserve(new_skb, NET_IP_ALIGN);
				new_skb->dev = netdev;
				memcpy(new_skb->data - NET_IP_ALIGN,
				       skb->data - NET_IP_ALIGN,
				       length + NET_IP_ALIGN);
				/* save the skb in buffer_info as good */
				buffer_info->skb = skb;
				skb = new_skb;
			}
		}
		/* end copybreak code */

		/* Good Receive */
		skb_put(skb, length);

		/* Receive Checksum Offload */
		ixgb_rx_checksum(adapter, rx_desc, skb);

		skb->protocol = eth_type_trans(skb, netdev);
#ifdef CONFIG_IXGB_NAPI
		if(adapter->vlgrp && (status & IXGB_RX_DESC_STATUS_VP)) {
			vlan_hwaccel_receive_skb(skb, adapter->vlgrp,
				le16_to_cpu(rx_desc->special) &
					IXGB_RX_DESC_SPECIAL_VLAN_MASK);
		} else {
			netif_receive_skb(skb);
		}
#else /* CONFIG_IXGB_NAPI */
		if(adapter->vlgrp && (status & IXGB_RX_DESC_STATUS_VP)) {
			vlan_hwaccel_rx(skb, adapter->vlgrp,
				le16_to_cpu(rx_desc->special) &
					IXGB_RX_DESC_SPECIAL_VLAN_MASK);
		} else {
			netif_rx(skb);
		}
#endif /* CONFIG_IXGB_NAPI */
		netdev->last_rx = jiffies;

rxdesc_done:
		/* clean up descriptor, might be written over by hw */
		rx_desc->status = 0;

		/* use prefetched values */
		rx_desc = next_rxd;
		buffer_info = next_buffer;
	}

	rx_ring->next_to_clean = i;

	ixgb_alloc_rx_buffers(adapter);

	return cleaned;
}

/**
 * ixgb_alloc_rx_buffers - Replace used receive buffers
 * @adapter: address of board private structure
 **/

static void
ixgb_alloc_rx_buffers(struct ixgb_adapter *adapter)
{
	struct ixgb_desc_ring *rx_ring = &adapter->rx_ring;
	struct net_device *netdev = adapter->netdev;
	struct pci_dev *pdev = adapter->pdev;
	struct ixgb_rx_desc *rx_desc;
	struct ixgb_buffer *buffer_info;
	struct sk_buff *skb;
	unsigned int i;
	int num_group_tail_writes;
	long cleancount;

	i = rx_ring->next_to_use;
	buffer_info = &rx_ring->buffer_info[i];
	cleancount = IXGB_DESC_UNUSED(rx_ring);

	num_group_tail_writes = IXGB_RX_BUFFER_WRITE;

	/* leave three descriptors unused */
	while(--cleancount > 2) {
		/* recycle! its good for you */
		if (!(skb = buffer_info->skb))
			skb = dev_alloc_skb(adapter->rx_buffer_len
			                    + NET_IP_ALIGN);
		else {
			skb_trim(skb, 0);
			goto map_skb;
		}

		if (unlikely(!skb)) {
			/* Better luck next round */
			adapter->alloc_rx_buff_failed++;
			break;
		}

		/* Make buffer alignment 2 beyond a 16 byte boundary
		 * this will result in a 16 byte aligned IP header after
		 * the 14 byte MAC header is removed
		 */
		skb_reserve(skb, NET_IP_ALIGN);

		skb->dev = netdev;

		buffer_info->skb = skb;
		buffer_info->length = adapter->rx_buffer_len;
map_skb:
		buffer_info->dma = pci_map_single(pdev,
		                                  skb->data,
		                                  adapter->rx_buffer_len,
		                                  PCI_DMA_FROMDEVICE);

		rx_desc = IXGB_RX_DESC(*rx_ring, i);
		rx_desc->buff_addr = cpu_to_le64(buffer_info->dma);
		/* guarantee DD bit not set now before h/w gets descriptor
		 * this is the rest of the workaround for h/w double 
		 * writeback. */
		rx_desc->status = 0;


		if(++i == rx_ring->count) i = 0;
		buffer_info = &rx_ring->buffer_info[i];
	}

	if (likely(rx_ring->next_to_use != i)) {
		rx_ring->next_to_use = i;
		if (unlikely(i-- == 0))
			i = (rx_ring->count - 1);

		/* Force memory writes to complete before letting h/w
		 * know there are new descriptors to fetch.  (Only
		 * applicable for weak-ordered memory model archs, such
		 * as IA-64). */
		wmb();
		IXGB_WRITE_REG(&adapter->hw, RDT, i);
	}
}

/**
 * ixgb_vlan_rx_register - enables or disables vlan tagging/stripping.
 * 
 * @param netdev network interface device structure
 * @param grp indicates to enable or disable tagging/stripping
 **/
static void
ixgb_vlan_rx_register(struct net_device *netdev, struct vlan_group *grp)
{
	struct ixgb_adapter *adapter = netdev_priv(netdev);
	uint32_t ctrl, rctl;

	ixgb_irq_disable(adapter);
	adapter->vlgrp = grp;

	if(grp) {
		/* enable VLAN tag insert/strip */
		ctrl = IXGB_READ_REG(&adapter->hw, CTRL0);
		ctrl |= IXGB_CTRL0_VME;
		IXGB_WRITE_REG(&adapter->hw, CTRL0, ctrl);

		/* enable VLAN receive filtering */

		rctl = IXGB_READ_REG(&adapter->hw, RCTL);
		rctl |= IXGB_RCTL_VFE;
		rctl &= ~IXGB_RCTL_CFIEN;
		IXGB_WRITE_REG(&adapter->hw, RCTL, rctl);
	} else {
		/* disable VLAN tag insert/strip */

		ctrl = IXGB_READ_REG(&adapter->hw, CTRL0);
		ctrl &= ~IXGB_CTRL0_VME;
		IXGB_WRITE_REG(&adapter->hw, CTRL0, ctrl);

		/* disable VLAN filtering */

		rctl = IXGB_READ_REG(&adapter->hw, RCTL);
		rctl &= ~IXGB_RCTL_VFE;
		IXGB_WRITE_REG(&adapter->hw, RCTL, rctl);
	}

	ixgb_irq_enable(adapter);
}

static void
ixgb_vlan_rx_add_vid(struct net_device *netdev, uint16_t vid)
{
	struct ixgb_adapter *adapter = netdev_priv(netdev);
	uint32_t vfta, index;

	/* add VID to filter table */

	index = (vid >> 5) & 0x7F;
	vfta = IXGB_READ_REG_ARRAY(&adapter->hw, VFTA, index);
	vfta |= (1 << (vid & 0x1F));
	ixgb_write_vfta(&adapter->hw, index, vfta);
}

static void
ixgb_vlan_rx_kill_vid(struct net_device *netdev, uint16_t vid)
{
	struct ixgb_adapter *adapter = netdev_priv(netdev);
	uint32_t vfta, index;

	ixgb_irq_disable(adapter);

	if(adapter->vlgrp)
		adapter->vlgrp->vlan_devices[vid] = NULL;

	ixgb_irq_enable(adapter);

	/* remove VID from filter table*/

	index = (vid >> 5) & 0x7F;
	vfta = IXGB_READ_REG_ARRAY(&adapter->hw, VFTA, index);
	vfta &= ~(1 << (vid & 0x1F));
	ixgb_write_vfta(&adapter->hw, index, vfta);
}

static void
ixgb_restore_vlan(struct ixgb_adapter *adapter)
{
	ixgb_vlan_rx_register(adapter->netdev, adapter->vlgrp);

	if(adapter->vlgrp) {
		uint16_t vid;
		for(vid = 0; vid < VLAN_GROUP_ARRAY_LEN; vid++) {
			if(!adapter->vlgrp->vlan_devices[vid])
				continue;
			ixgb_vlan_rx_add_vid(adapter->netdev, vid);
		}
	}
}

#ifdef CONFIG_NET_POLL_CONTROLLER
/*
 * Polling 'interrupt' - used by things like netconsole to send skbs
 * without having to re-enable interrupts. It's not called while
 * the interrupt routine is executing.
 */

static void ixgb_netpoll(struct net_device *dev)
{
	struct ixgb_adapter *adapter = dev->priv;

	disable_irq(adapter->pdev->irq);
	ixgb_intr(adapter->pdev->irq, dev, NULL);
	enable_irq(adapter->pdev->irq);
}
#endif

/* ixgb_main.c */