e1000_main-2.6.37-ethercat.c

			cpu_to_le32(txd_lower | buffer_info->length);
		tx_desc->upper.data = cpu_to_le32(txd_upper);
		if (unlikely(++i == tx_ring->count)) i = 0;
	}

	tx_desc->lower.data |= cpu_to_le32(adapter->txd_cmd);

	/* 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;
	writel(i, hw->hw_addr + tx_ring->tdt);
	/* we need this if more than one processor can write to our tail
	 * at a time, it syncronizes IO on IA64/Altix systems */
	mmiowb();
}

/**
 * 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 by notifying the stack to resend
 * the packet at a later time.  This gives the Tx FIFO an opportunity to
 * flush all packets.  When that occurs, we reset the Tx FIFO pointers
 * to the beginning of the Tx FIFO.
 **/

#define E1000_FIFO_HDR			0x10
#define E1000_82547_PAD_LEN		0x3E0

static int e1000_82547_fifo_workaround(struct e1000_adapter *adapter,
				       struct sk_buff *skb)
{
	u32 fifo_space = adapter->tx_fifo_size - adapter->tx_fifo_head;
	u32 skb_fifo_len = skb->len + E1000_FIFO_HDR;

	skb_fifo_len = ALIGN(skb_fifo_len, E1000_FIFO_HDR);

	if (adapter->link_duplex != HALF_DUPLEX)
		goto no_fifo_stall_required;

	if (atomic_read(&adapter->tx_fifo_stall))
		return 1;

	if (skb_fifo_len >= (E1000_82547_PAD_LEN + fifo_space)) {
		atomic_set(&adapter->tx_fifo_stall, 1);
		return 1;
	}

no_fifo_stall_required:
	adapter->tx_fifo_head += skb_fifo_len;
	if (adapter->tx_fifo_head >= adapter->tx_fifo_size)
		adapter->tx_fifo_head -= adapter->tx_fifo_size;
	return 0;
}

static int __e1000_maybe_stop_tx(struct net_device *netdev, int size)
{
	struct e1000_adapter *adapter = netdev_priv(netdev);
	struct e1000_tx_ring *tx_ring = adapter->tx_ring;

	netif_stop_queue(netdev);
	/* Herbert's original patch had:
	 *  smp_mb__after_netif_stop_queue();
	 * but since that doesn't exist yet, just open code it. */
	smp_mb();

	/* We need to check again in a case another CPU has just
	 * made room available. */
	if (likely(E1000_DESC_UNUSED(tx_ring) < size))
		return -EBUSY;

	/* A reprieve! */
	netif_start_queue(netdev);
	++adapter->restart_queue;
	return 0;
}

static int e1000_maybe_stop_tx(struct net_device *netdev,
                               struct e1000_tx_ring *tx_ring, int size)
{
	if (likely(E1000_DESC_UNUSED(tx_ring) >= size))
		return 0;
	return __e1000_maybe_stop_tx(netdev, size);
}

#define TXD_USE_COUNT(S, X) (((S) >> (X)) + 1 )
static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb,
				    struct net_device *netdev)
{
	struct e1000_adapter *adapter = netdev_priv(netdev);
	struct e1000_hw *hw = &adapter->hw;
	struct e1000_tx_ring *tx_ring;
	unsigned int first, max_per_txd = E1000_MAX_DATA_PER_TXD;
	unsigned int max_txd_pwr = E1000_MAX_TXD_PWR;
	unsigned int tx_flags = 0;
	unsigned int len = skb_headlen(skb);
	unsigned int nr_frags;
	unsigned int mss;
	int count = 0;
	int tso;
	unsigned int f;

	/* This goes back to the question of how to logically map a tx queue
	 * to a flow.  Right now, performance is impacted slightly negatively
	 * if using multiple tx queues.  If the stack breaks away from a
	 * single qdisc implementation, we can look at this again. */
	tx_ring = adapter->tx_ring;

	if (unlikely(skb->len <= 0)) {
		if (!adapter->ecdev)
			dev_kfree_skb_any(skb);
		return NETDEV_TX_OK;
	}

	mss = skb_shinfo(skb)->gso_size;
	/* The controller does a simple calculation to
	 * make sure there is enough room in the FIFO before
	 * initiating the DMA for each buffer.  The calc is:
	 * 4 = ceil(buffer len/mss).  To make sure we don't
	 * overrun the FIFO, adjust the max buffer len if mss
	 * drops. */
	if (mss) {
		u8 hdr_len;
		max_per_txd = min(mss << 2, max_per_txd);
		max_txd_pwr = fls(max_per_txd) - 1;

		hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
		if (skb->data_len && hdr_len == len) {
			switch (hw->mac_type) {
				unsigned int pull_size;
			case e1000_82544:
				/* Make sure we have room to chop off 4 bytes,
				 * and that the end alignment will work out to
				 * this hardware's requirements
				 * NOTE: this is a TSO only workaround
				 * if end byte alignment not correct move us
				 * into the next dword */
				if ((unsigned long)(skb_tail_pointer(skb) - 1) & 4)
					break;
				/* fall through */
				pull_size = min((unsigned int)4, skb->data_len);
				if (!__pskb_pull_tail(skb, pull_size)) {
					e_err(drv, "__pskb_pull_tail "
					      "failed.\n");
					dev_kfree_skb_any(skb);
					return NETDEV_TX_OK;
				}
				len = skb_headlen(skb);
				break;
			default:
				/* do nothing */
				break;
			}
		}
	}

	/* reserve a descriptor for the offload context */
	if ((mss) || (skb->ip_summed == CHECKSUM_PARTIAL))
		count++;
	count++;

	/* Controller Erratum workaround */
	if (!skb->data_len && tx_ring->last_tx_tso && !skb_is_gso(skb))
		count++;

	count += TXD_USE_COUNT(len, max_txd_pwr);

	if (adapter->pcix_82544)
		count++;

	/* work-around for errata 10 and it applies to all controllers
	 * in PCI-X mode, so add one more descriptor to the count
	 */
	if (unlikely((hw->bus_type == e1000_bus_type_pcix) &&
			(len > 2015)))
		count++;

	nr_frags = skb_shinfo(skb)->nr_frags;
	for (f = 0; f < nr_frags; f++)
		count += TXD_USE_COUNT(skb_shinfo(skb)->frags[f].size,
				       max_txd_pwr);
	if (adapter->pcix_82544)
		count += nr_frags;

	/* need: count + 2 desc gap to keep tail from touching
	 * head, otherwise try next time */
	if (unlikely(e1000_maybe_stop_tx(netdev, tx_ring, count + 2)))
		return NETDEV_TX_BUSY;

	if (unlikely(hw->mac_type == e1000_82547)) {
		if (unlikely(e1000_82547_fifo_workaround(adapter, skb))) {
			if (!adapter->ecdev) {
				netif_stop_queue(netdev);
				if (!test_bit(__E1000_DOWN, &adapter->flags))
					mod_timer(&adapter->tx_fifo_stall_timer,
					          jiffies + 1);
			}
			return NETDEV_TX_BUSY;
		}
	}

	if (unlikely(vlan_tx_tag_present(skb))) {
		tx_flags |= E1000_TX_FLAGS_VLAN;
		tx_flags |= (vlan_tx_tag_get(skb) << E1000_TX_FLAGS_VLAN_SHIFT);
	}

	first = tx_ring->next_to_use;

	tso = e1000_tso(adapter, tx_ring, skb);
	if (tso < 0) {
		if (!adapter->ecdev) {
			dev_kfree_skb_any(skb);
		}
		return NETDEV_TX_OK;
	}

	if (likely(tso)) {
		if (likely(hw->mac_type != e1000_82544))
			tx_ring->last_tx_tso = 1;
		tx_flags |= E1000_TX_FLAGS_TSO;
	} else if (likely(e1000_tx_csum(adapter, tx_ring, skb)))
		tx_flags |= E1000_TX_FLAGS_CSUM;

	if (likely(skb->protocol == htons(ETH_P_IP)))
		tx_flags |= E1000_TX_FLAGS_IPV4;

	count = e1000_tx_map(adapter, tx_ring, skb, first, max_per_txd,
	                     nr_frags, mss);

	if (count) {
		e1000_tx_queue(adapter, tx_ring, tx_flags, count);
		if (!adapter->ecdev) {
			/* Make sure there is space in the ring for the next send. */
			e1000_maybe_stop_tx(netdev, tx_ring, MAX_SKB_FRAGS + 2);
		}

	} else {
		if (!adapter->ecdev) dev_kfree_skb_any(skb);
		tx_ring->buffer_info[first].time_stamp = 0;
		tx_ring->next_to_use = first;
	}

	return NETDEV_TX_OK;
}

/**
 * e1000_tx_timeout - Respond to a Tx Hang
 * @netdev: network interface device structure
 **/

static void e1000_tx_timeout(struct net_device *netdev)
{
	struct e1000_adapter *adapter = netdev_priv(netdev);

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

static void e1000_reset_task(struct work_struct *work)
{
	struct e1000_adapter *adapter =
		container_of(work, struct e1000_adapter, reset_task);

	e1000_reinit_safe(adapter);
}

/**
 * e1000_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 *e1000_get_stats(struct net_device *netdev)
{
	/* only return the current stats */
	return &netdev->stats;
}

/**
 * e1000_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 e1000_change_mtu(struct net_device *netdev, int new_mtu)
{
	struct e1000_adapter *adapter = netdev_priv(netdev);
	struct e1000_hw *hw = &adapter->hw;
	int max_frame = new_mtu + ENET_HEADER_SIZE + ETHERNET_FCS_SIZE;

	if (adapter->ecdev)
		return -EBUSY;

	if ((max_frame < MINIMUM_ETHERNET_FRAME_SIZE) ||
	    (max_frame > MAX_JUMBO_FRAME_SIZE)) {
		e_err(probe, "Invalid MTU setting\n");
		return -EINVAL;
	}

	/* Adapter-specific max frame size limits. */
	switch (hw->mac_type) {
	case e1000_undefined ... e1000_82542_rev2_1:
		if (max_frame > (ETH_FRAME_LEN + ETH_FCS_LEN)) {
			e_err(probe, "Jumbo Frames not supported.\n");
			return -EINVAL;
		}
		break;
	default:
		/* Capable of supporting up to MAX_JUMBO_FRAME_SIZE limit. */
		break;
	}

	while (test_and_set_bit(__E1000_RESETTING, &adapter->flags))
		msleep(1);
	/* e1000_down has a dependency on max_frame_size */
	hw->max_frame_size = max_frame;
	if (netif_running(netdev))
		e1000_down(adapter);

	/* NOTE: netdev_alloc_skb reserves 16 bytes, and typically NET_IP_ALIGN
	 * means we reserve 2 more, this pushes us to allocate from the next
	 * larger slab size.
	 * i.e. RXBUFFER_2048 --> size-4096 slab
	 *  however with the new *_jumbo_rx* routines, jumbo receives will use
	 *  fragmented skbs */

	if (max_frame <= E1000_RXBUFFER_2048)
		adapter->rx_buffer_len = E1000_RXBUFFER_2048;
	else
#if (PAGE_SIZE >= E1000_RXBUFFER_16384)
		adapter->rx_buffer_len = E1000_RXBUFFER_16384;
#elif (PAGE_SIZE >= E1000_RXBUFFER_4096)
		adapter->rx_buffer_len = PAGE_SIZE;
#endif

	/* adjust allocation if LPE protects us, and we aren't using SBP */
	if (!hw->tbi_compatibility_on &&
	    ((max_frame == (ETH_FRAME_LEN + ETH_FCS_LEN)) ||
	     (max_frame == MAXIMUM_ETHERNET_VLAN_SIZE)))
		adapter->rx_buffer_len = MAXIMUM_ETHERNET_VLAN_SIZE;

	pr_info("%s changing MTU from %d to %d\n",
		netdev->name, netdev->mtu, new_mtu);
	netdev->mtu = new_mtu;

	if (netif_running(netdev))
		e1000_up(adapter);
	else
		e1000_reset(adapter);

	clear_bit(__E1000_RESETTING, &adapter->flags);

	return 0;
}

/**
 * e1000_update_stats - Update the board statistics counters
 * @adapter: board private structure
 **/

void e1000_update_stats(struct e1000_adapter *adapter)
{
	struct net_device *netdev = adapter->netdev;
	struct e1000_hw *hw = &adapter->hw;
	struct pci_dev *pdev = adapter->pdev;
	unsigned long flags = 0;
	u16 phy_tmp;

#define PHY_IDLE_ERROR_COUNT_MASK 0x00FF

	/*
	 * Prevent stats update while adapter is being reset, or if the pci
	 * connection is down.
	 */
	if (adapter->link_speed == 0)
		return;
	if (pci_channel_offline(pdev))
		return;

	if (!adapter->ecdev)
		spin_lock_irqsave(&adapter->stats_lock, flags);

	/* these counters are modified from e1000_tbi_adjust_stats,
	 * called from the interrupt context, so they must only
	 * be written while holding adapter->stats_lock
	 */

	adapter->stats.crcerrs += er32(CRCERRS);
	adapter->stats.gprc += er32(GPRC);
	adapter->stats.gorcl += er32(GORCL);
	adapter->stats.gorch += er32(GORCH);
	adapter->stats.bprc += er32(BPRC);
	adapter->stats.mprc += er32(MPRC);
	adapter->stats.roc += er32(ROC);

	adapter->stats.prc64 += er32(PRC64);
	adapter->stats.prc127 += er32(PRC127);
	adapter->stats.prc255 += er32(PRC255);
	adapter->stats.prc511 += er32(PRC511);
	adapter->stats.prc1023 += er32(PRC1023);
	adapter->stats.prc1522 += er32(PRC1522);

	adapter->stats.symerrs += er32(SYMERRS);
	adapter->stats.mpc += er32(MPC);
	adapter->stats.scc += er32(SCC);
	adapter->stats.ecol += er32(ECOL);
	adapter->stats.mcc += er32(MCC);
	adapter->stats.latecol += er32(LATECOL);
	adapter->stats.dc += er32(DC);
	adapter->stats.sec += er32(SEC);
	adapter->stats.rlec += er32(RLEC);
	adapter->stats.xonrxc += er32(XONRXC);
	adapter->stats.xontxc += er32(XONTXC);
	adapter->stats.xoffrxc += er32(XOFFRXC);
	adapter->stats.xofftxc += er32(XOFFTXC);
	adapter->stats.fcruc += er32(FCRUC);
	adapter->stats.gptc += er32(GPTC);
	adapter->stats.gotcl += er32(GOTCL);
	adapter->stats.gotch += er32(GOTCH);
	adapter->stats.rnbc += er32(RNBC);
	adapter->stats.ruc += er32(RUC);
	adapter->stats.rfc += er32(RFC);
	adapter->stats.rjc += er32(RJC);
	adapter->stats.torl += er32(TORL);
	adapter->stats.torh += er32(TORH);
	adapter->stats.totl += er32(TOTL);
	adapter->stats.toth += er32(TOTH);
	adapter->stats.tpr += er32(TPR);

	adapter->stats.ptc64 += er32(PTC64);
	adapter->stats.ptc127 += er32(PTC127);
	adapter->stats.ptc255 += er32(PTC255);
	adapter->stats.ptc511 += er32(PTC511);
	adapter->stats.ptc1023 += er32(PTC1023);
	adapter->stats.ptc1522 += er32(PTC1522);

	adapter->stats.mptc += er32(MPTC);
	adapter->stats.bptc += er32(BPTC);

	/* used for adaptive IFS */

	hw->tx_packet_delta = er32(TPT);
	adapter->stats.tpt += hw->tx_packet_delta;
	hw->collision_delta = er32(COLC);
	adapter->stats.colc += hw->collision_delta;

	if (hw->mac_type >= e1000_82543) {
		adapter->stats.algnerrc += er32(ALGNERRC);
		adapter->stats.rxerrc += er32(RXERRC);
		adapter->stats.tncrs += er32(TNCRS);
		adapter->stats.cexterr += er32(CEXTERR);
		adapter->stats.tsctc += er32(TSCTC);
		adapter->stats.tsctfc += er32(TSCTFC);
	}

	/* Fill out the OS statistics structure */
	netdev->stats.multicast = adapter->stats.mprc;
	netdev->stats.collisions = adapter->stats.colc;

	/* Rx Errors */

	/* RLEC on some newer hardware can be incorrect so build
	* our own version based on RUC and ROC */
	netdev->stats.rx_errors = adapter->stats.rxerrc +
		adapter->stats.crcerrs + adapter->stats.algnerrc +
		adapter->stats.ruc + adapter->stats.roc +
		adapter->stats.cexterr;
	adapter->stats.rlerrc = adapter->stats.ruc + adapter->stats.roc;
	netdev->stats.rx_length_errors = adapter->stats.rlerrc;
	netdev->stats.rx_crc_errors = adapter->stats.crcerrs;
	netdev->stats.rx_frame_errors = adapter->stats.algnerrc;
	netdev->stats.rx_missed_errors = adapter->stats.mpc;

	/* Tx Errors */
	adapter->stats.txerrc = adapter->stats.ecol + adapter->stats.latecol;
	netdev->stats.tx_errors = adapter->stats.txerrc;
	netdev->stats.tx_aborted_errors = adapter->stats.ecol;
	netdev->stats.tx_window_errors = adapter->stats.latecol;
	netdev->stats.tx_carrier_errors = adapter->stats.tncrs;
	if (hw->bad_tx_carr_stats_fd &&
	    adapter->link_duplex == FULL_DUPLEX) {
		netdev->stats.tx_carrier_errors = 0;
		adapter->stats.tncrs = 0;
	}

	/* Tx Dropped needs to be maintained elsewhere */

	/* Phy Stats */
	if (hw->media_type == e1000_media_type_copper) {
		if ((adapter->link_speed == SPEED_1000) &&
		   (!e1000_read_phy_reg(hw, PHY_1000T_STATUS, &phy_tmp))) {
			phy_tmp &= PHY_IDLE_ERROR_COUNT_MASK;
			adapter->phy_stats.idle_errors += phy_tmp;
		}

		if ((hw->mac_type <= e1000_82546) &&
		   (hw->phy_type == e1000_phy_m88) &&
		   !e1000_read_phy_reg(hw, M88E1000_RX_ERR_CNTR, &phy_tmp))
			adapter->phy_stats.receive_errors += phy_tmp;
	}

	/* Management Stats */
	if (hw->has_smbus) {
		adapter->stats.mgptc += er32(MGTPTC);
		adapter->stats.mgprc += er32(MGTPRC);
		adapter->stats.mgpdc += er32(MGTPDC);
	}

	if (!adapter->ecdev)
		spin_unlock_irqrestore(&adapter->stats_lock, flags);
}

void ec_poll(struct net_device *netdev)
{
	struct e1000_adapter *adapter = netdev_priv(netdev);
	if (jiffies - adapter->ec_watchdog_jiffies >= 2 * HZ) {
		e1000_watchdog((unsigned long) adapter);
		adapter->ec_watchdog_jiffies = jiffies;
	}

	e1000_intr(0, netdev);
}

/**
 * e1000_intr - Interrupt Handler
 * @irq: interrupt number
 * @data: pointer to a network interface device structure
 **/

static irqreturn_t e1000_intr(int irq, void *data)
{
	struct net_device *netdev = data;
	struct e1000_adapter *adapter = netdev_priv(netdev);
	struct e1000_hw *hw = &adapter->hw;
	u32 icr = er32(ICR);

	if (unlikely((!icr) || test_bit(__E1000_DOWN, &adapter->flags)))
		return IRQ_NONE;  /* Not our interrupt */

    if (unlikely(icr & (E1000_ICR_RXSEQ | E1000_ICR_LSC))) {
		hw->get_link_status = 1;
		/* guard against interrupt when we're going down */
		if (!test_bit(__E1000_DOWN, &adapter->flags))
			mod_timer(&adapter->watchdog_timer, jiffies + 1);
	}

	if (adapter->ecdev) {
		int i, ec_work_done = 0;
		for (i = 0; i < E1000_MAX_INTR; i++) {
			if (unlikely(!adapter->clean_rx(adapter, adapter->rx_ring,
							&ec_work_done, 100) &&
						!e1000_clean_tx_irq(adapter, adapter->tx_ring))) {
				break;
			}
		}
	} else {
		/* disable interrupts, without the synchronize_irq bit */
		ew32(IMC, ~0);
		E1000_WRITE_FLUSH();

		if (likely(napi_schedule_prep(&adapter->napi))) {
			adapter->total_tx_bytes = 0;
			adapter->total_tx_packets = 0;
			adapter->total_rx_bytes = 0;
			adapter->total_rx_packets = 0;
			__napi_schedule(&adapter->napi);
		} else {
			/* this really should not happen! if it does it is basically a
			 * bug, but not a hard error, so enable ints and continue */
			if (!test_bit(__E1000_DOWN, &adapter->flags))
				e1000_irq_enable(adapter);
		}
	}

	return IRQ_HANDLED;
}

/**
 * e1000_clean - NAPI Rx polling callback
 * @adapter: board private structure
 * EtherCAT: never called
 **/
static int e1000_clean(struct napi_struct *napi, int budget)
{
	struct e1000_adapter *adapter = container_of(napi, struct e1000_adapter, napi);
	int tx_clean_complete = 0, work_done = 0;

	tx_clean_complete = e1000_clean_tx_irq(adapter, &adapter->tx_ring[0]);

	adapter->clean_rx(adapter, &adapter->rx_ring[0], &work_done, budget);

	if (!tx_clean_complete)
		work_done = budget;

	/* If budget not fully consumed, exit the polling mode */
	if (work_done < budget) {
		if (likely(adapter->itr_setting & 3))
			e1000_set_itr(adapter);
		napi_complete(napi);
		if (!test_bit(__E1000_DOWN, &adapter->flags))
			e1000_irq_enable(adapter);
	}

	return work_done;
}

/**
 * e1000_clean_tx_irq - Reclaim resources after transmit completes
 * @adapter: board private structure
 **/
static bool e1000_clean_tx_irq(struct e1000_adapter *adapter,
			       struct e1000_tx_ring *tx_ring)
{
	struct e1000_hw *hw = &adapter->hw;
	struct net_device *netdev = adapter->netdev;
	struct e1000_tx_desc *tx_desc, *eop_desc;
	struct e1000_buffer *buffer_info;
	unsigned int i, eop;
	unsigned int count = 0;
	unsigned int total_tx_bytes=0, total_tx_packets=0;

	i = tx_ring->next_to_clean;
	eop = tx_ring->buffer_info[i].next_to_watch;
	eop_desc = E1000_TX_DESC(*tx_ring, eop);

	while ((eop_desc->upper.data & cpu_to_le32(E1000_TXD_STAT_DD)) &&
	       (count < tx_ring->count)) {
		bool cleaned = false;
		rmb();	/* read buffer_info after eop_desc */
		for ( ; !cleaned; count++) {
			tx_desc = E1000_TX_DESC(*tx_ring, i);
			buffer_info = &tx_ring->buffer_info[i];
			cleaned = (i == eop);

			if (cleaned) {
				struct sk_buff *skb = buffer_info->skb;
				unsigned int segs, bytecount;
				segs = skb_shinfo(skb)->gso_segs ?: 1;
				/* multiply data chunks by size of headers */
				bytecount = ((segs - 1) * skb_headlen(skb)) +
				            skb->len;
				total_tx_packets += segs;
				total_tx_bytes += bytecount;
			}
			e1000_unmap_and_free_tx_resource(adapter, buffer_info);
			tx_desc->upper.data = 0;

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

		eop = tx_ring->buffer_info[i].next_to_watch;
		eop_desc = E1000_TX_DESC(*tx_ring, eop);
	}

	tx_ring->next_to_clean = i;

#define TX_WAKE_THRESHOLD 32
	if (!adapter->ecdev && unlikely(count && netif_carrier_ok(netdev) &&
		     E1000_DESC_UNUSED(tx_ring) >= TX_WAKE_THRESHOLD)) {
		/* Make sure that anybody stopping the queue after this
		 * sees the new next_to_clean.
		 */
		smp_mb();

		if (netif_queue_stopped(netdev) &&
		    !(test_bit(__E1000_DOWN, &adapter->flags))) {
			netif_wake_queue(netdev);
			++adapter->restart_queue;
		}
	}

	if (!adapter->ecdev && 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].time_stamp &&
		    time_after(jiffies, tx_ring->buffer_info[eop].time_stamp +
		               (adapter->tx_timeout_factor * HZ)) &&
		    !(er32(STATUS) & E1000_STATUS_TXOFF)) {

			/* detected Tx unit hang */
			e_err(drv, "Detected Tx Unit Hang\n"
			      "  Tx Queue             <%lu>\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",
				(unsigned long)((tx_ring - adapter->tx_ring) /
					sizeof(struct e1000_tx_ring)),
				readl(hw->hw_addr + tx_ring->tdh),
				readl(hw->hw_addr + tx_ring->tdt),
				tx_ring->next_to_use,
				tx_ring->next_to_clean,
				tx_ring->buffer_info[eop].time_stamp,
				eop,
				jiffies,
				eop_desc->upper.fields.status);
			netif_stop_queue(netdev);
		}
	}
	adapter->total_tx_bytes += total_tx_bytes;
	adapter->total_tx_packets += total_tx_packets;
	netdev->stats.tx_bytes += total_tx_bytes;
	netdev->stats.tx_packets += total_tx_packets;
	return count < tx_ring->count;
}

/**
 * e1000_rx_checksum - Receive Checksum Offload for 82543
 * @adapter:     board private structure
 * @status_err:  receive descriptor status and error fields
 * @csum:        receive descriptor csum field
 * @sk_buff:     socket buffer with received data
 **/

static void e1000_rx_checksum(struct e1000_adapter *adapter, u32 status_err,
			      u32 csum, struct sk_buff *skb)
{
	struct e1000_hw *hw = &adapter->hw;
	u16 status = (u16)status_err;
	u8 errors = (u8)(status_err >> 24);

	skb_checksum_none_assert(skb);

	/* 82543 or newer only */
	if (unlikely(hw->mac_type < e1000_82543)) return;
	/* Ignore Checksum bit is set */
	if (unlikely(status & E1000_RXD_STAT_IXSM)) return;
	/* TCP/UDP checksum error bit is set */
	if (unlikely(errors & E1000_RXD_ERR_TCPE)) {
		/* let the stack verify checksum errors */
		adapter->hw_csum_err++;
		return;
	}
	/* TCP/UDP Checksum has not been calculated */
	if (!(status & E1000_RXD_STAT_TCPCS))
		return;

	/* It must be a TCP or UDP packet with a valid checksum */
	if (likely(status & E1000_RXD_STAT_TCPCS)) {
		/* TCP checksum is good */
		skb->ip_summed = CHECKSUM_UNNECESSARY;
	}
	adapter->hw_csum_good++;
}

/**
 * e1000_consume_page - helper function
 **/
static void e1000_consume_page(struct e1000_buffer *bi, struct sk_buff *skb,
                               u16 length)
{
	bi->page = NULL;
	skb->len += length;
	skb->data_len += length;
	skb->truesize += length;
}

/**
 * e1000_receive_skb - helper function to handle rx indications
 * @adapter: board private structure
 * @status: descriptor status field as written by hardware
 * @vlan: descriptor vlan field as written by hardware (no le/be conversion)
 * @skb: pointer to sk_buff to be indicated to stack
 */
static void e1000_receive_skb(struct e1000_adapter *adapter, u8 status,
			      __le16 vlan, struct sk_buff *skb)
{
	skb->protocol = eth_type_trans(skb, adapter->netdev);

	if ((unlikely(adapter->vlgrp && (status & E1000_RXD_STAT_VP))))
		vlan_gro_receive(&adapter->napi, adapter->vlgrp,
				 le16_to_cpu(vlan) & E1000_RXD_SPC_VLAN_MASK,
				 skb);
	else
		napi_gro_receive(&adapter->napi, skb);
}

/**
 * e1000_clean_jumbo_rx_irq - Send received data up the network stack; legacy
 * @adapter: board private structure
 * @rx_ring: ring to clean
 * @work_done: amount of napi work completed this call
 * @work_to_do: max amount of work allowed for this call to do
 *
 * the return value indicates whether actual cleaning was done, there
 * is no guarantee that everything was cleaned
 */
static bool e1000_clean_jumbo_rx_irq(struct e1000_adapter *adapter,
				     struct e1000_rx_ring *rx_ring,
				     int *work_done, int work_to_do)
{
	struct e1000_hw *hw = &adapter->hw;
	struct net_device *netdev = adapter->netdev;
	struct pci_dev *pdev = adapter->pdev;
	struct e1000_rx_desc *rx_desc, *next_rxd;
	struct e1000_buffer *buffer_info, *next_buffer;
	unsigned long irq_flags;
	u32 length;
	unsigned int i;
	int cleaned_count = 0;
	bool cleaned = false;
	unsigned int total_rx_bytes=0, total_rx_packets=0;

	i = rx_ring->next_to_clean;
	rx_desc = E1000_RX_DESC(*rx_ring, i);
	buffer_info = &rx_ring->buffer_info[i];

	while (rx_desc->status & E1000_RXD_STAT_DD) {
		struct sk_buff *skb;
		u8 status;

		if (*work_done >= work_to_do)
			break;
		(*work_done)++;
		rmb(); /* read descriptor and rx_buffer_info after status DD */

		status = rx_desc->status;
		skb = buffer_info->skb;
		if (!adapter->ecdev) buffer_info->skb = NULL;

		if (++i == rx_ring->count) i = 0;
		next_rxd = E1000_RX_DESC(*rx_ring, i);
		prefetch(next_rxd);

		next_buffer = &rx_ring->buffer_info[i];

		cleaned = true;
		cleaned_count++;
		dma_unmap_page(&pdev->dev, buffer_info->dma,
			       buffer_info->length, DMA_FROM_DEVICE);
		buffer_info->dma = 0;

		length = le16_to_cpu(rx_desc->length);

		/* errors is only valid for DD + EOP descriptors */
		if (!adapter->ecdev &&
		    unlikely((status & E1000_RXD_STAT_EOP) &&
		    (rx_desc->errors & E1000_RXD_ERR_FRAME_ERR_MASK))) {
			u8 last_byte = *(skb->data + length - 1);
			if (TBI_ACCEPT(hw, status, rx_desc->errors, length,
				       last_byte)) {
				spin_lock_irqsave(&adapter->stats_lock,
				                  irq_flags);
				e1000_tbi_adjust_stats(hw, &adapter->stats,
				                       length, skb->data);
				spin_unlock_irqrestore(&adapter->stats_lock,
				                       irq_flags);
				length--;
			} else {
				/* recycle both page and skb */
				buffer_info->skb = skb;
				/* an error means any chain goes out the window
				 * too */
				if (rx_ring->rx_skb_top)
					dev_kfree_skb(rx_ring->rx_skb_top);
				rx_ring->rx_skb_top = NULL;
				goto next_desc;
			}
		}

#define rxtop rx_ring->rx_skb_top
		if (!(status & E1000_RXD_STAT_EOP)) {
			/* this descriptor is only the beginning (or middle) */
			if (!rxtop) {
				/* this is the beginning of a chain */
				rxtop = skb;
				skb_fill_page_desc(rxtop, 0, buffer_info->page,
				                   0, length);
			} else {
				/* this is the middle of a chain */
				skb_fill_page_desc(rxtop,
				    skb_shinfo(rxtop)->nr_frags,
				    buffer_info->page, 0, length);
				/* re-use the skb, only consumed the page */
				buffer_info->skb = skb;
			}
			e1000_consume_page(buffer_info, rxtop, length);
			goto next_desc;
		} else {
			if (rxtop) {
				/* end of the chain */
				skb_fill_page_desc(rxtop,
				    skb_shinfo(rxtop)->nr_frags,
				    buffer_info->page, 0, length);
				/* re-use the current skb, we only consumed the
				 * page */
				buffer_info->skb = skb;
				skb = rxtop;
				rxtop = NULL;
				e1000_consume_page(buffer_info, skb, length);
			} else {
				/* no chain, got EOP, this buf is the packet
				 * copybreak to save the put_page/alloc_page */
				if (length <= copybreak &&
				    skb_tailroom(skb) >= length) {
					u8 *vaddr;
					vaddr = kmap_atomic(buffer_info->page,
					                    KM_SKB_DATA_SOFTIRQ);
					memcpy(skb_tail_pointer(skb), vaddr, length);
					kunmap_atomic(vaddr,
					              KM_SKB_DATA_SOFTIRQ);
					/* re-use the page, so don't erase
					 * buffer_info->page */
					skb_put(skb, length);
				} else {
					skb_fill_page_desc(skb, 0,
					                   buffer_info->page, 0,
				                           length);
					e1000_consume_page(buffer_info, skb,
					                   length);
				}
			}
		}

		/* Receive Checksum Offload XXX recompute due to CRC strip? */
		e1000_rx_checksum(adapter,
		                  (u32)(status) |
		                  ((u32)(rx_desc->errors) << 24),
		                  le16_to_cpu(rx_desc->csum), skb);

		pskb_trim(skb, skb->len - 4);

		/* probably a little skewed due to removing CRC */
		total_rx_bytes += skb->len;
		total_rx_packets++;

		/* eth type trans needs skb->data to point to something */
		if (!pskb_may_pull(skb, ETH_HLEN)) {
			e_err(drv, "pskb_may_pull failed.\n");
			if (!adapter->ecdev) {
				dev_kfree_skb(skb);
			}
			goto next_desc;
		}

		if (adapter->ecdev) {
			ecdev_receive(adapter->ecdev, skb->data, length);

			// No need to detect link status as
			// long as frames are received: Reset watchdog.
			adapter->ec_watchdog_jiffies = jiffies;
		} else {
			e1000_receive_skb(adapter, status, rx_desc->special, skb);
		}

next_desc:
		rx_desc->status = 0;

		/* return some buffers to hardware, one at a time is too slow */
		if (unlikely(cleaned_count >= E1000_RX_BUFFER_WRITE)) {
			adapter->alloc_rx_buf(adapter, rx_ring, cleaned_count);
			cleaned_count = 0;
		}

		/* use prefetched values */
		rx_desc = next_rxd;
		buffer_info = next_buffer;
	}
	rx_ring->next_to_clean = i;

	cleaned_count = E1000_DESC_UNUSED(rx_ring);
	if (cleaned_count)
		adapter->alloc_rx_buf(adapter, rx_ring, cleaned_count);

	adapter->total_rx_packets += total_rx_packets;
	adapter->total_rx_bytes += total_rx_bytes;
	netdev->stats.rx_bytes += total_rx_bytes;
	netdev->stats.rx_packets += total_rx_packets;
	return cleaned;
}

/*
 * this should improve performance for small packets with large amounts
 * of reassembly being done in the stack
 */
static void e1000_check_copybreak(struct net_device *netdev,
				 struct e1000_buffer *buffer_info,
				 u32 length, struct sk_buff **skb)
{
	struct e1000_adapter *adapter = netdev_priv(netdev);
	struct sk_buff *new_skb;

	if (adapter->ecdev || length > copybreak)
		return;

	new_skb = netdev_alloc_skb_ip_align(netdev, length);