Add support for the latest 1G/10G Chelsio adapter, T3.

This driver is required by the Chelsio T3 RDMA driver posted by
Steve Wise.

Signed-off-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 2702 insertions, 0 deletions

diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c
new file mode 100644
index 00000000000..6c77f4bab62
--- /dev/null
+++ b/drivers/net/cxgb3/sge.c
@@ -0,0 +1,2702 @@
+/*
+ * This file is part of the Chelsio T3 Ethernet driver.
+ *
+ * Copyright (C) 2005-2006 Chelsio Communications.  All rights reserved.
+ *
+ * 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 LICENSE file included in this
+ * release for licensing terms and conditions.
+ */
+
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/if_vlan.h>
+#include <linux/ip.h>
+#include <linux/tcp.h>
+#include <linux/dma-mapping.h>
+#include "common.h"
+#include "regs.h"
+#include "sge_defs.h"
+#include "t3_cpl.h"
+#include "firmware_exports.h"
+
+#define USE_GTS 0
+
+#define SGE_RX_SM_BUF_SIZE 1536
+#define SGE_RX_COPY_THRES  256
+
+# define SGE_RX_DROP_THRES 16
+
+/*
+ * Period of the Tx buffer reclaim timer.  This timer does not need to run
+ * frequently as Tx buffers are usually reclaimed by new Tx packets.
+ */
+#define TX_RECLAIM_PERIOD (HZ / 4)
+
+/* WR size in bytes */
+#define WR_LEN (WR_FLITS * 8)
+
+/*
+ * Types of Tx queues in each queue set.  Order here matters, do not change.
+ */
+enum { TXQ_ETH, TXQ_OFLD, TXQ_CTRL };
+
+/* Values for sge_txq.flags */
+enum {
+	TXQ_RUNNING = 1 << 0,	/* fetch engine is running */
+	TXQ_LAST_PKT_DB = 1 << 1,	/* last packet rang the doorbell */
+};
+
+struct tx_desc {
+	u64 flit[TX_DESC_FLITS];
+};
+
+struct rx_desc {
+	__be32 addr_lo;
+	__be32 len_gen;
+	__be32 gen2;
+	__be32 addr_hi;
+};
+
+struct tx_sw_desc {		/* SW state per Tx descriptor */
+	struct sk_buff *skb;
+};
+
+struct rx_sw_desc {		/* SW state per Rx descriptor */
+	struct sk_buff *skb;
+	 DECLARE_PCI_UNMAP_ADDR(dma_addr);
+};
+
+struct rsp_desc {		/* response queue descriptor */
+	struct rss_header rss_hdr;
+	__be32 flags;
+	__be32 len_cq;
+	u8 imm_data[47];
+	u8 intr_gen;
+};
+
+struct unmap_info {		/* packet unmapping info, overlays skb->cb */
+	int sflit;		/* start flit of first SGL entry in Tx descriptor */
+	u16 fragidx;		/* first page fragment in current Tx descriptor */
+	u16 addr_idx;		/* buffer index of first SGL entry in descriptor */
+	u32 len;		/* mapped length of skb main body */
+};
+
+/*
+ * Maps a number of flits to the number of Tx descriptors that can hold them.
+ * The formula is
+ *
+ * desc = 1 + (flits - 2) / (WR_FLITS - 1).
+ *
+ * HW allows up to 4 descriptors to be combined into a WR.
+ */
+static u8 flit_desc_map[] = {
+	0,
+#if SGE_NUM_GENBITS == 1
+	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+	2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+	3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+	4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4
+#elif SGE_NUM_GENBITS == 2
+	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+	2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+	3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+	4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+#else
+# error "SGE_NUM_GENBITS must be 1 or 2"
+#endif
+};
+
+static inline struct sge_qset *fl_to_qset(const struct sge_fl *q, int qidx)
+{
+	return container_of(q, struct sge_qset, fl[qidx]);
+}
+
+static inline struct sge_qset *rspq_to_qset(const struct sge_rspq *q)
+{
+	return container_of(q, struct sge_qset, rspq);
+}
+
+static inline struct sge_qset *txq_to_qset(const struct sge_txq *q, int qidx)
+{
+	return container_of(q, struct sge_qset, txq[qidx]);
+}
+
+/**
+ *	refill_rspq - replenish an SGE response queue
+ *	@adapter: the adapter
+ *	@q: the response queue to replenish
+ *	@credits: how many new responses to make available
+ *
+ *	Replenishes a response queue by making the supplied number of responses
+ *	available to HW.
+ */
+static inline void refill_rspq(struct adapter *adapter,
+			       const struct sge_rspq *q, unsigned int credits)
+{
+	t3_write_reg(adapter, A_SG_RSPQ_CREDIT_RETURN,
+		     V_RSPQ(q->cntxt_id) | V_CREDITS(credits));
+}
+
+/**
+ *	need_skb_unmap - does the platform need unmapping of sk_buffs?
+ *
+ *	Returns true if the platfrom needs sk_buff unmapping.  The compiler
+ *	optimizes away unecessary code if this returns true.
+ */
+static inline int need_skb_unmap(void)
+{
+	/*
+	 * This structure is used to tell if the platfrom needs buffer
+	 * unmapping by checking if DECLARE_PCI_UNMAP_ADDR defines anything.
+	 */
+	struct dummy {
+		DECLARE_PCI_UNMAP_ADDR(addr);
+	};
+
+	return sizeof(struct dummy) != 0;
+}
+
+/**
+ *	unmap_skb - unmap a packet main body and its page fragments
+ *	@skb: the packet
+ *	@q: the Tx queue containing Tx descriptors for the packet
+ *	@cidx: index of Tx descriptor
+ *	@pdev: the PCI device
+ *
+ *	Unmap the main body of an sk_buff and its page fragments, if any.
+ *	Because of the fairly complicated structure of our SGLs and the desire
+ *	to conserve space for metadata, we keep the information necessary to
+ *	unmap an sk_buff partly in the sk_buff itself (in its cb), and partly
+ *	in the Tx descriptors (the physical addresses of the various data
+ *	buffers).  The send functions initialize the state in skb->cb so we
+ *	can unmap the buffers held in the first Tx descriptor here, and we
+ *	have enough information at this point to update the state for the next
+ *	Tx descriptor.
+ */
+static inline void unmap_skb(struct sk_buff *skb, struct sge_txq *q,
+			     unsigned int cidx, struct pci_dev *pdev)
+{
+	const struct sg_ent *sgp;
+	struct unmap_info *ui = (struct unmap_info *)skb->cb;
+	int nfrags, frag_idx, curflit, j = ui->addr_idx;
+
+	sgp = (struct sg_ent *)&q->desc[cidx].flit[ui->sflit];
+
+	if (ui->len) {
+		pci_unmap_single(pdev, be64_to_cpu(sgp->addr[0]), ui->len,
+				 PCI_DMA_TODEVICE);
+		ui->len = 0;	/* so we know for next descriptor for this skb */
+		j = 1;
+	}
+
+	frag_idx = ui->fragidx;
+	curflit = ui->sflit + 1 + j;
+	nfrags = skb_shinfo(skb)->nr_frags;
+
+	while (frag_idx < nfrags && curflit < WR_FLITS) {
+		pci_unmap_page(pdev, be64_to_cpu(sgp->addr[j]),
+			       skb_shinfo(skb)->frags[frag_idx].size,
+			       PCI_DMA_TODEVICE);
+		j ^= 1;
+		if (j == 0) {
+			sgp++;
+			curflit++;
+		}
+		curflit++;
+		frag_idx++;
+	}
+
+	if (frag_idx < nfrags) {	/* SGL continues into next Tx descriptor */
+		ui->fragidx = frag_idx;
+		ui->addr_idx = j;
+		ui->sflit = curflit - WR_FLITS - j;	/* sflit can be -1 */
+	}
+}
+
+/**
+ *	free_tx_desc - reclaims Tx descriptors and their buffers
+ *	@adapter: the adapter
+ *	@q: the Tx queue to reclaim descriptors from
+ *	@n: the number of descriptors to reclaim
+ *
+ *	Reclaims Tx descriptors from an SGE Tx queue and frees the associated
+ *	Tx buffers.  Called with the Tx queue lock held.
+ */
+static void free_tx_desc(struct adapter *adapter, struct sge_txq *q,
+			 unsigned int n)
+{
+	struct tx_sw_desc *d;
+	struct pci_dev *pdev = adapter->pdev;
+	unsigned int cidx = q->cidx;
+
+	d = &q->sdesc[cidx];
+	while (n--) {
+		if (d->skb) {	/* an SGL is present */
+			if (need_skb_unmap())
+				unmap_skb(d->skb, q, cidx, pdev);
+			if (d->skb->priority == cidx)
+				kfree_skb(d->skb);
+		}
+		++d;
+		if (++cidx == q->size) {
+			cidx = 0;
+			d = q->sdesc;
+		}
+	}
+	q->cidx = cidx;
+}
+
+/**
+ *	reclaim_completed_tx - reclaims completed Tx descriptors
+ *	@adapter: the adapter
+ *	@q: the Tx queue to reclaim completed descriptors from
+ *
+ *	Reclaims Tx descriptors that the SGE has indicated it has processed,
+ *	and frees the associated buffers if possible.  Called with the Tx
+ *	queue's lock held.
+ */
+static inline void reclaim_completed_tx(struct adapter *adapter,
+					struct sge_txq *q)
+{
+	unsigned int reclaim = q->processed - q->cleaned;
+
+	if (reclaim) {
+		free_tx_desc(adapter, q, reclaim);
+		q->cleaned += reclaim;
+		q->in_use -= reclaim;
+	}
+}
+
+/**
+ *	should_restart_tx - are there enough resources to restart a Tx queue?
+ *	@q: the Tx queue
+ *
+ *	Checks if there are enough descriptors to restart a suspended Tx queue.
+ */
+static inline int should_restart_tx(const struct sge_txq *q)
+{
+	unsigned int r = q->processed - q->cleaned;
+
+	return q->in_use - r < (q->size >> 1);
+}
+
+/**
+ *	free_rx_bufs - free the Rx buffers on an SGE free list
+ *	@pdev: the PCI device associated with the adapter
+ *	@rxq: the SGE free list to clean up
+ *
+ *	Release the buffers on an SGE free-buffer Rx queue.  HW fetching from
+ *	this queue should be stopped before calling this function.
+ */
+static void free_rx_bufs(struct pci_dev *pdev, struct sge_fl *q)
+{
+	unsigned int cidx = q->cidx;
+
+	while (q->credits--) {
+		struct rx_sw_desc *d = &q->sdesc[cidx];
+
+		pci_unmap_single(pdev, pci_unmap_addr(d, dma_addr),
+				 q->buf_size, PCI_DMA_FROMDEVICE);
+		kfree_skb(d->skb);
+		d->skb = NULL;
+		if (++cidx == q->size)
+			cidx = 0;
+	}
+}
+
+/**
+ *	add_one_rx_buf - add a packet buffer to a free-buffer list
+ *	@skb: the buffer to add
+ *	@len: the buffer length
+ *	@d: the HW Rx descriptor to write
+ *	@sd: the SW Rx descriptor to write
+ *	@gen: the generation bit value
+ *	@pdev: the PCI device associated with the adapter
+ *
+ *	Add a buffer of the given length to the supplied HW and SW Rx
+ *	descriptors.
+ */
+static inline void add_one_rx_buf(struct sk_buff *skb, unsigned int len,
+				  struct rx_desc *d, struct rx_sw_desc *sd,
+				  unsigned int gen, struct pci_dev *pdev)
+{
+	dma_addr_t mapping;
+
+	sd->skb = skb;
+	mapping = pci_map_single(pdev, skb->data, len, PCI_DMA_FROMDEVICE);
+	pci_unmap_addr_set(sd, dma_addr, mapping);
+
+	d->addr_lo = cpu_to_be32(mapping);
+	d->addr_hi = cpu_to_be32((u64) mapping >> 32);
+	wmb();
+	d->len_gen = cpu_to_be32(V_FLD_GEN1(gen));
+	d->gen2 = cpu_to_be32(V_FLD_GEN2(gen));
+}
+
+/**
+ *	refill_fl - refill an SGE free-buffer list
+ *	@adapter: the adapter
+ *	@q: the free-list to refill
+ *	@n: the number of new buffers to allocate
+ *	@gfp: the gfp flags for allocating new buffers
+ *
+ *	(Re)populate an SGE free-buffer list with up to @n new packet buffers,
+ *	allocated with the supplied gfp flags.  The caller must assure that
+ *	@n does not exceed the queue's capacity.
+ */
+static void refill_fl(struct adapter *adap, struct sge_fl *q, int n, gfp_t gfp)
+{
+	struct rx_sw_desc *sd = &q->sdesc[q->pidx];
+	struct rx_desc *d = &q->desc[q->pidx];
+
+	while (n--) {
+		struct sk_buff *skb = alloc_skb(q->buf_size, gfp);
+
+		if (!skb)
+			break;
+
+		add_one_rx_buf(skb, q->buf_size, d, sd, q->gen, adap->pdev);
+		d++;
+		sd++;
+		if (++q->pidx == q->size) {
+			q->pidx = 0;
+			q->gen ^= 1;
+			sd = q->sdesc;
+			d = q->desc;
+		}
+		q->credits++;
+	}
+
+	t3_write_reg(adap, A_SG_KDOORBELL, V_EGRCNTX(q->cntxt_id));
+}
+
+static inline void __refill_fl(struct adapter *adap, struct sge_fl *fl)
+{
+	refill_fl(adap, fl, min(16U, fl->size - fl->credits), GFP_ATOMIC);
+}
+
+/**
+ *	recycle_rx_buf - recycle a receive buffer
+ *	@adapter: the adapter
+ *	@q: the SGE free list
+ *	@idx: index of buffer to recycle
+ *
+ *	Recycles the specified buffer on the given free list by adding it at
+ *	the next available slot on the list.
+ */
+static void recycle_rx_buf(struct adapter *adap, struct sge_fl *q,
+			   unsigned int idx)
+{
+	struct rx_desc *from = &q->desc[idx];
+	struct rx_desc *to = &q->desc[q->pidx];
+
+	q->sdesc[q->pidx] = q->sdesc[idx];
+	to->addr_lo = from->addr_lo;	/* already big endian */
+	to->addr_hi = from->addr_hi;	/* likewise */
+	wmb();
+	to->len_gen = cpu_to_be32(V_FLD_GEN1(q->gen));
+	to->gen2 = cpu_to_be32(V_FLD_GEN2(q->gen));
+	q->credits++;
+
+	if (++q->pidx == q->size) {
+		q->pidx = 0;
+		q->gen ^= 1;
+	}
+	t3_write_reg(adap, A_SG_KDOORBELL, V_EGRCNTX(q->cntxt_id));
+}
+
+/**
+ *	alloc_ring - allocate resources for an SGE descriptor ring
+ *	@pdev: the PCI device
+ *	@nelem: the number of descriptors
+ *	@elem_size: the size of each descriptor
+ *	@sw_size: the size of the SW state associated with each ring element
+ *	@phys: the physical address of the allocated ring
+ *	@metadata: address of the array holding the SW state for the ring
+ *
+ *	Allocates resources for an SGE descriptor ring, such as Tx queues,
+ *	free buffer lists, or response queues.  Each SGE ring requires
+ *	space for its HW descriptors plus, optionally, space for the SW state
+ *	associated with each HW entry (the metadata).  The function returns
+ *	three values: the virtual address for the HW ring (the return value
+ *	of the function), the physical address of the HW ring, and the address
+ *	of the SW ring.
+ */
+static void *alloc_ring(struct pci_dev *pdev, size_t nelem, size_t elem_size,
+			size_t sw_size, dma_addr_t *phys, void *metadata)
+{
+	size_t len = nelem * elem_size;
+	void *s = NULL;
+	void *p = dma_alloc_coherent(&pdev->dev, len, phys, GFP_KERNEL);
+
+	if (!p)
+		return NULL;
+	if (sw_size) {
+		s = kcalloc(nelem, sw_size, GFP_KERNEL);
+
+		if (!s) {
+			dma_free_coherent(&pdev->dev, len, p, *phys);
+			return NULL;
+		}
+	}
+	if (metadata)
+		*(void **)metadata = s;
+	memset(p, 0, len);
+	return p;
+}
+
+/**
+ *	free_qset - free the resources of an SGE queue set
+ *	@adapter: the adapter owning the queue set
+ *	@q: the queue set
+ *
+ *	Release the HW and SW resources associated with an SGE queue set, such
+ *	as HW contexts, packet buffers, and descriptor rings.  Traffic to the
+ *	queue set must be quiesced prior to calling this.
+ */
+void t3_free_qset(struct adapter *adapter, struct sge_qset *q)
+{
+	int i;
+	struct pci_dev *pdev = adapter->pdev;
+
+	if (q->tx_reclaim_timer.function)
+		del_timer_sync(&q->tx_reclaim_timer);
+
+	for (i = 0; i < SGE_RXQ_PER_SET; ++i)
+		if (q->fl[i].desc) {
+			spin_lock(&adapter->sge.reg_lock);
+			t3_sge_disable_fl(adapter, q->fl[i].cntxt_id);
+			spin_unlock(&adapter->sge.reg_lock);
+			free_rx_bufs(pdev, &q->fl[i]);
+			kfree(q->fl[i].sdesc);
+			dma_free_coherent(&pdev->dev,
+					  q->fl[i].size *
+					  sizeof(struct rx_desc), q->fl[i].desc,
+					  q->fl[i].phys_addr);
+		}
+
+	for (i = 0; i < SGE_TXQ_PER_SET; ++i)
+		if (q->txq[i].desc) {
+			spin_lock(&adapter->sge.reg_lock);
+			t3_sge_enable_ecntxt(adapter, q->txq[i].cntxt_id, 0);
+			spin_unlock(&adapter->sge.reg_lock);
+			if (q->txq[i].sdesc) {
+				free_tx_desc(adapter, &q->txq[i],
+					     q->txq[i].in_use);
+				kfree(q->txq[i].sdesc);
+			}
+			dma_free_coherent(&pdev->dev,
+					  q->txq[i].size *
+					  sizeof(struct tx_desc),
+					  q->txq[i].desc, q->txq[i].phys_addr);
+			__skb_queue_purge(&q->txq[i].sendq);
+		}
+
+	if (q->rspq.desc) {
+		spin_lock(&adapter->sge.reg_lock);
+		t3_sge_disable_rspcntxt(adapter, q->rspq.cntxt_id);
+		spin_unlock(&adapter->sge.reg_lock);
+		dma_free_coherent(&pdev->dev,
+				  q->rspq.size * sizeof(struct rsp_desc),
+				  q->rspq.desc, q->rspq.phys_addr);
+	}
+
+	if (q->netdev)
+		q->netdev->atalk_ptr = NULL;
+
+	memset(q, 0, sizeof(*q));
+}
+
+/**
+ *	init_qset_cntxt - initialize an SGE queue set context info
+ *	@qs: the queue set
+ *	@id: the queue set id
+ *
+ *	Initializes the TIDs and context ids for the queues of a queue set.
+ */
+static void init_qset_cntxt(struct sge_qset *qs, unsigned int id)
+{
+	qs->rspq.cntxt_id = id;
+	qs->fl[0].cntxt_id = 2 * id;
+	qs->fl[1].cntxt_id = 2 * id + 1;
+	qs->txq[TXQ_ETH].cntxt_id = FW_TUNNEL_SGEEC_START + id;
+	qs->txq[TXQ_ETH].token = FW_TUNNEL_TID_START + id;
+	qs->txq[TXQ_OFLD].cntxt_id = FW_OFLD_SGEEC_START + id;
+	qs->txq[TXQ_CTRL].cntxt_id = FW_CTRL_SGEEC_START + id;
+	qs->txq[TXQ_CTRL].token = FW_CTRL_TID_START + id;
+}
+
+/**
+ *	sgl_len - calculates the size of an SGL of the given capacity
+ *	@n: the number of SGL entries
+ *
+ *	Calculates the number of flits needed for a scatter/gather list that
+ *	can hold the given number of entries.
+ */
+static inline unsigned int sgl_len(unsigned int n)
+{
+	/* alternatively: 3 * (n / 2) + 2 * (n & 1) */
+	return (3 * n) / 2 + (n & 1);
+}
+
+/**
+ *	flits_to_desc - returns the num of Tx descriptors for the given flits
+ *	@n: the number of flits
+ *
+ *	Calculates the number of Tx descriptors needed for the supplied number
+ *	of flits.
+ */
+static inline unsigned int flits_to_desc(unsigned int n)
+{
+	BUG_ON(n >= ARRAY_SIZE(flit_desc_map));
+	return flit_desc_map[n];
+}
+
+/**
+ *	get_packet - return the next ingress packet buffer from a free list
+ *	@adap: the adapter that received the packet
+ *	@fl: the SGE free list holding the packet
+ *	@len: the packet length including any SGE padding
+ *	@drop_thres: # of remaining buffers before we start dropping packets
+ *
+ *	Get the next packet from a free list and complete setup of the
+ *	sk_buff.  If the packet is small we make a copy and recycle the
+ *	original buffer, otherwise we use the original buffer itself.  If a
+ *	positive drop threshold is supplied packets are dropped and their
+ *	buffers recycled if (a) the number of remaining buffers is under the
+ *	threshold and the packet is too big to copy, or (b) the packet should
+ *	be copied but there is no memory for the copy.
+ */
+static struct sk_buff *get_packet(struct adapter *adap, struct sge_fl *fl,
+				  unsigned int len, unsigned int drop_thres)
+{
+	struct sk_buff *skb = NULL;
+	struct rx_sw_desc *sd = &fl->sdesc[fl->cidx];
+
+	prefetch(sd->skb->data);
+
+	if (len <= SGE_RX_COPY_THRES) {
+		skb = alloc_skb(len, GFP_ATOMIC);
+		if (likely(skb != NULL)) {
+			__skb_put(skb, len);
+			pci_dma_sync_single_for_cpu(adap->pdev,
+						    pci_unmap_addr(sd,
+								   dma_addr),
+						    len, PCI_DMA_FROMDEVICE);
+			memcpy(skb->data, sd->skb->data, len);
+			pci_dma_sync_single_for_device(adap->pdev,
+						       pci_unmap_addr(sd,
+								      dma_addr),
+						       len, PCI_DMA_FROMDEVICE);
+		} else if (!drop_thres)
+			goto use_orig_buf;
+	      recycle:
+		recycle_rx_buf(adap, fl, fl->cidx);
+		return skb;
+	}
+
+	if (unlikely(fl->credits < drop_thres))
+		goto recycle;
+
+      use_orig_buf:
+	pci_unmap_single(adap->pdev, pci_unmap_addr(sd, dma_addr),
+			 fl->buf_size, PCI_DMA_FROMDEVICE);
+	skb = sd->skb;
+	skb_put(skb, len);
+	__refill_fl(adap, fl);
+	return skb;
+}
+
+/**
+ *	get_imm_packet - return the next ingress packet buffer from a response
+ *	@resp: the response descriptor containing the packet data
+ *
+ *	Return a packet containing the immediate data of the given response.
+ */
+static inline struct sk_buff *get_imm_packet(const struct rsp_desc *resp)
+{
+	struct sk_buff *skb = alloc_skb(IMMED_PKT_SIZE, GFP_ATOMIC);
+
+	if (skb) {
+		__skb_put(skb, IMMED_PKT_SIZE);
+		memcpy(skb->data, resp->imm_data, IMMED_PKT_SIZE);
+	}
+	return skb;
+}
+
+/**
+ *	calc_tx_descs - calculate the number of Tx descriptors for a packet
+ *	@skb: the packet
+ *
+ * 	Returns the number of Tx descriptors needed for the given Ethernet
+ * 	packet.  Ethernet packets require addition of WR and CPL headers.
+ */
+static inline unsigned int calc_tx_descs(const struct sk_buff *skb)
+{
+	unsigned int flits;
+
+	if (skb->len <= WR_LEN - sizeof(struct cpl_tx_pkt))
+		return 1;
+
+	flits = sgl_len(skb_shinfo(skb)->nr_frags + 1) + 2;
+	if (skb_shinfo(skb)->gso_size)
+		flits++;
+	return flits_to_desc(flits);
+}
+
+/**
+ *	make_sgl - populate a scatter/gather list for a packet
+ *	@skb: the packet
+ *	@sgp: the SGL to populate
+ *	@start: start address of skb main body data to include in the SGL
+ *	@len: length of skb main body data to include in the SGL
+ *	@pdev: the PCI device
+ *
+ *	Generates a scatter/gather list for the buffers that make up a packet
+ *	and returns the SGL size in 8-byte words.  The caller must size the SGL
+ *	appropriately.
+ */
+static inline unsigned int make_sgl(const struct sk_buff *skb,
+				    struct sg_ent *sgp, unsigned char *start,
+				    unsigned int len, struct pci_dev *pdev)
+{
+	dma_addr_t mapping;
+	unsigned int i, j = 0, nfrags;
+
+	if (len) {
+		mapping = pci_map_single(pdev, start, len, PCI_DMA_TODEVICE);
+		sgp->len[0] = cpu_to_be32(len);
+		sgp->addr[0] = cpu_to_be64(mapping);
+		j = 1;
+	}
+
+	nfrags = skb_shinfo(skb)->nr_frags;
+	for (i = 0; i < nfrags; i++) {
+		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+		mapping = pci_map_page(pdev, frag->page, frag->page_offset,
+				       frag->size, PCI_DMA_TODEVICE);
+		sgp->len[j] = cpu_to_be32(frag->size);
+		sgp->addr[j] = cpu_to_be64(mapping);
+		j ^= 1;
+		if (j == 0)
+			++sgp;
+	}
+	if (j)
+		sgp->len[j] = 0;
+	return ((nfrags + (len != 0)) * 3) / 2 + j;
+}
+
+/**
+ *	check_ring_tx_db - check and potentially ring a Tx queue's doorbell
+ *	@adap: the adapter
+ *	@q: the Tx queue
+ *
+ *	Ring the doorbel if a Tx queue is asleep.  There is a natural race,
+ *	where the HW is going to sleep just after we checked, however,
+ *	then the interrupt handler will detect the outstanding TX packet
+ *	and ring the doorbell for us.
+ *
+ *	When GTS is disabled we unconditionally ring the doorbell.
+ */
+static inline void check_ring_tx_db(struct adapter *adap, struct sge_txq *q)
+{
+#if USE_GTS
+	clear_bit(TXQ_LAST_PKT_DB, &q->flags);
+	if (test_and_set_bit(TXQ_RUNNING, &q->flags) == 0) {
+		set_bit(TXQ_LAST_PKT_DB, &q->flags);
+		t3_write_reg(adap, A_SG_KDOORBELL,
+			     F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
+	}
+#else
+	wmb();			/* write descriptors before telling HW */
+	t3_write_reg(adap, A_SG_KDOORBELL,
+		     F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
+#endif
+}
+
+static inline void wr_gen2(struct tx_desc *d, unsigned int gen)
+{
+#if SGE_NUM_GENBITS == 2
+	d->flit[TX_DESC_FLITS - 1] = cpu_to_be64(gen);
+#endif
+}
+
+/**
+ *	write_wr_hdr_sgl - write a WR header and, optionally, SGL
+ *	@ndesc: number of Tx descriptors spanned by the SGL
+ *	@skb: the packet corresponding to the WR
+ *	@d: first Tx descriptor to be written
+ *	@pidx: index of above descriptors
+ *	@q: the SGE Tx queue
+ *	@sgl: the SGL
+ *	@flits: number of flits to the start of the SGL in the first descriptor
+ *	@sgl_flits: the SGL size in flits
+ *	@gen: the Tx descriptor generation
+ *	@wr_hi: top 32 bits of WR header based on WR type (big endian)
+ *	@wr_lo: low 32 bits of WR header based on WR type (big endian)
+ *
+ *	Write a work request header and an associated SGL.  If the SGL is
+ *	small enough to fit into one Tx descriptor it has already been written
+ *	and we just need to write the WR header.  Otherwise we distribute the
+ *	SGL across the number of descriptors it spans.
+ */
+static void write_wr_hdr_sgl(unsigned int ndesc, struct sk_buff *skb,
+			     struct tx_desc *d, unsigned int pidx,
+			     const struct sge_txq *q,
+			     const struct sg_ent *sgl,
+			     unsigned int flits, unsigned int sgl_flits,
+			     unsigned int gen, unsigned int wr_hi,
+			     unsigned int wr_lo)
+{
+	struct work_request_hdr *wrp = (struct work_request_hdr *)d;
+	struct tx_sw_desc *sd = &q->sdesc[pidx];
+
+	sd->skb = skb;
+	if (need_skb_unmap()) {
+		struct unmap_info *ui = (struct unmap_info *)skb->cb;
+
+		ui->fragidx = 0;
+		ui->addr_idx = 0;
+		ui->sflit = flits;
+	}
+
+	if (likely(ndesc == 1)) {
+		skb->priority = pidx;
+		wrp->wr_hi = htonl(F_WR_SOP | F_WR_EOP | V_WR_DATATYPE(1) |
+				   V_WR_SGLSFLT(flits)) | wr_hi;
+		wmb();
+		wrp->wr_lo = htonl(V_WR_LEN(flits + sgl_flits) |
+				   V_WR_GEN(gen)) | wr_lo;
+		wr_gen2(d, gen);
+	} else {
+		unsigned int ogen = gen;
+		const u64 *fp = (const u64 *)sgl;
+		struct work_request_hdr *wp = wrp;
+
+		wrp->wr_hi = htonl(F_WR_SOP | V_WR_DATATYPE(1) |
+				   V_WR_SGLSFLT(flits)) | wr_hi;
+
+		while (sgl_flits) {
+			unsigned int avail = WR_FLITS - flits;
+
+			if (avail > sgl_flits)
+				avail = sgl_flits;
+			memcpy(&d->flit[flits], fp, avail * sizeof(*fp));
+			sgl_flits -= avail;
+			ndesc--;
+			if (!sgl_flits)
+				break;
+
+			fp += avail;
+			d++;
+			sd++;
+			if (++pidx == q->size) {
+				pidx = 0;
+				gen ^= 1;
+				d = q->desc;
+				sd = q->sdesc;
+			}
+
+			sd->skb = skb;
+			wrp = (struct work_request_hdr *)d;
+			wrp->wr_hi = htonl(V_WR_DATATYPE(1) |
+					   V_WR_SGLSFLT(1)) | wr_hi;
+			wrp->wr_lo = htonl(V_WR_LEN(min(WR_FLITS,
+							sgl_flits + 1)) |
+					   V_WR_GEN(gen)) | wr_lo;
+			wr_gen2(d, gen);
+			flits = 1;
+		}
+		skb->priority = pidx;
+		wrp->wr_hi |= htonl(F_WR_EOP);
+		wmb();
+		wp->wr_lo = htonl(V_WR_LEN(WR_FLITS) | V_WR_GEN(ogen)) | wr_lo;
+		wr_gen2((struct tx_desc *)wp, ogen);
+		WARN_ON(ndesc != 0);
+	}
+}
+
+/**
+ *	write_tx_pkt_wr - write a TX_PKT work request
+ *	@adap: the adapter
+ *	@skb: the packet to send
+ *	@pi: the egress interface
+ *	@pidx: index of the first Tx descriptor to write
+ *	@gen: the generation value to use
+ *	@q: the Tx queue
+ *	@ndesc: number of descriptors the packet will occupy
+ *	@compl: the value of the COMPL bit to use
+ *
+ *	Generate a TX_PKT work request to send the supplied packet.
+ */
+static void write_tx_pkt_wr(struct adapter *adap, struct sk_buff *skb,
+			    const struct port_info *pi,
+			    unsigned int pidx, unsigned int gen,
+			    struct sge_txq *q, unsigned int ndesc,
+			    unsigned int compl)
+{
+	unsigned int flits, sgl_flits, cntrl, tso_info;
+	struct sg_ent *sgp, sgl[MAX_SKB_FRAGS / 2 + 1];
+	struct tx_desc *d = &q->desc[pidx];
+	struct cpl_tx_pkt *cpl = (struct cpl_tx_pkt *)d;
+
+	cpl->len = htonl(skb->len | 0x80000000);
+	cntrl = V_TXPKT_INTF(pi->port_id);
+
+	if (vlan_tx_tag_present(skb) && pi->vlan_grp)
+		cntrl |= F_TXPKT_VLAN_VLD | V_TXPKT_VLAN(vlan_tx_tag_get(skb));
+
+	tso_info = V_LSO_MSS(skb_shinfo(skb)->gso_size);
+	if (tso_info) {
+		int eth_type;
+		struct cpl_tx_pkt_lso *hdr = (struct cpl_tx_pkt_lso *)cpl;
+
+		d->flit[2] = 0;
+		cntrl |= V_TXPKT_OPCODE(CPL_TX_PKT_LSO);
+		hdr->cntrl = htonl(cntrl);
+		eth_type = skb->nh.raw - skb->data == ETH_HLEN ?
+		    CPL_ETH_II : CPL_ETH_II_VLAN;
+		tso_info |= V_LSO_ETH_TYPE(eth_type) |
+		    V_LSO_IPHDR_WORDS(skb->nh.iph->ihl) |
+		    V_LSO_TCPHDR_WORDS(skb->h.th->doff);
+		hdr->lso_info = htonl(tso_info);
+		flits = 3;
+	} else {
+		cntrl |= V_TXPKT_OPCODE(CPL_TX_PKT);
+		cntrl |= F_TXPKT_IPCSUM_DIS;	/* SW calculates IP csum */
+		cntrl |= V_TXPKT_L4CSUM_DIS(skb->ip_summed != CHECKSUM_PARTIAL);
+		cpl->cntrl = htonl(cntrl);
+
+		if (skb->len <= WR_LEN - sizeof(*cpl)) {
+			q->sdesc[pidx].skb = NULL;
+			if (!skb->data_len)
+				memcpy(&d->flit[2], skb->data, skb->len);
+			else
+				skb_copy_bits(skb, 0, &d->flit[2], skb->len);
+
+			flits = (skb->len + 7) / 8 + 2;
+			cpl->wr.wr_hi = htonl(V_WR_BCNTLFLT(skb->len & 7) |
+					      V_WR_OP(FW_WROPCODE_TUNNEL_TX_PKT)
+					      | F_WR_SOP | F_WR_EOP | compl);
+			wmb();
+			cpl->wr.wr_lo = htonl(V_WR_LEN(flits) | V_WR_GEN(gen) |
+					      V_WR_TID(q->token));
+			wr_gen2(d, gen);
+			kfree_skb(skb);
+			return;
+		}
+
+		flits = 2;
+	}
+
+	sgp = ndesc == 1 ? (struct sg_ent *)&d->flit[flits] : sgl;
+	sgl_flits = make_sgl(skb, sgp, skb->data, skb_headlen(skb), adap->pdev);
+	if (need_skb_unmap())
+		((struct unmap_info *)skb->cb)->len = skb_headlen(skb);
+
+	write_wr_hdr_sgl(ndesc, skb, d, pidx, q, sgl, flits, sgl_flits, gen,
+			 htonl(V_WR_OP(FW_WROPCODE_TUNNEL_TX_PKT) | compl),
+			 htonl(V_WR_TID(q->token)));
+}
+
+/**
+ *	eth_xmit - add a packet to the Ethernet Tx queue
+ *	@skb: the packet
+ *	@dev: the egress net device
+ *
+ *	Add a packet to an SGE Tx queue.  Runs with softirqs disabled.
+ */
+int t3_eth_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	unsigned int ndesc, pidx, credits, gen, compl;
+	const struct port_info *pi = netdev_priv(dev);
+	struct adapter *adap = dev->priv;
+	struct sge_qset *qs = dev2qset(dev);
+	struct sge_txq *q = &qs->txq[TXQ_ETH];
+
+	/*
+	 * The chip min packet length is 9 octets but play safe and reject
+	 * anything shorter than an Ethernet header.
+	 */
+	if (unlikely(skb->len < ETH_HLEN)) {
+		dev_kfree_skb(skb);
+		return NETDEV_TX_OK;
+	}
+
+	spin_lock(&q->lock);
+	reclaim_completed_tx(adap, q);
+
+	credits = q->size - q->in_use;
+	ndesc = calc_tx_descs(skb);
+
+	if (unlikely(credits < ndesc)) {
+		if (!netif_queue_stopped(dev)) {
+			netif_stop_queue(dev);
+			set_bit(TXQ_ETH, &qs->txq_stopped);
+			q->stops++;
+			dev_err(&adap->pdev->dev,
+				"%s: Tx ring %u full while queue awake!\n",
+				dev->name, q->cntxt_id & 7);
+		}
+		spin_unlock(&q->lock);
+		return NETDEV_TX_BUSY;
+	}
+
+	q->in_use += ndesc;
+	if (unlikely(credits - ndesc < q->stop_thres)) {
+		q->stops++;
+		netif_stop_queue(dev);
+		set_bit(TXQ_ETH, &qs->txq_stopped);
+#if !USE_GTS
+		if (should_restart_tx(q) &&
+		    test_and_clear_bit(TXQ_ETH, &qs->txq_stopped)) {
+			q->restarts++;
+			netif_wake_queue(dev);
+		}
+#endif
+	}
+
+	gen = q->gen;
+	q->unacked += ndesc;
+	compl = (q->unacked & 8) << (S_WR_COMPL - 3);
+	q->unacked &= 7;
+	pidx = q->pidx;
+	q->pidx += ndesc;
+	if (q->pidx >= q->size) {
+		q->pidx -= q->size;
+		q->gen ^= 1;
+	}
+
+	/* update port statistics */
+	if (skb->ip_summed == CHECKSUM_COMPLETE)
+		qs->port_stats[SGE_PSTAT_TX_CSUM]++;
+	if (skb_shinfo(skb)->gso_size)
+		qs->port_stats[SGE_PSTAT_TSO]++;
+	if (vlan_tx_tag_present(skb) && pi->vlan_grp)
+		qs->port_stats[SGE_PSTAT_VLANINS]++;
+
+	dev->trans_start = jiffies;
+	spin_unlock(&q->lock);
+
+	/*
+	 * We do not use Tx completion interrupts to free DMAd Tx packets.
+	 * This is good for performamce but means that we rely on new Tx
+	 * packets arriving to run the destructors of completed packets,
+	 * which open up space in their sockets' send queues.  Sometimes
+	 * we do not get such new packets causing Tx to stall.  A single
+	 * UDP transmitter is a good example of this situation.  We have
+	 * a clean up timer that periodically reclaims completed packets
+	 * but it doesn't run often enough (nor do we want it to) to prevent
+	 * lengthy stalls.  A solution to this problem is to run the
+	 * destructor early, after the packet is queued but before it's DMAd.
+	 * A cons is that we lie to socket memory accounting, but the amount
+	 * of extra memory is reasonable (limited by the number of Tx
+	 * descriptors), the packets do actually get freed quickly by new
+	 * packets almost always, and for protocols like TCP that wait for
+	 * acks to really free up the data the extra memory is even less.
+	 * On the positive side we run the destructors on the sending CPU
+	 * rather than on a potentially different completing CPU, usually a
+	 * good thing.  We also run them without holding our Tx queue lock,
+	 * unlike what reclaim_completed_tx() would otherwise do.
+	 *
+	 * Run the destructor before telling the DMA engine about the packet
+	 * to make sure it doesn't complete and get freed prematurely.
+	 */
+	if (likely(!skb_shared(skb)))
+		skb_orphan(skb);
+
+	write_tx_pkt_wr(adap, skb, pi, pidx, gen, q, ndesc, compl);
+	check_ring_tx_db(adap, q);
+	return NETDEV_TX_OK;
+}
+
+/**
+ *	write_imm - write a packet into a Tx descriptor as immediate data
+ *	@d: the Tx descriptor to write
+ *	@skb: the packet
+ *	@len: the length of packet data to write as immediate data
+ *	@gen: the generation bit value to write
+ *
+ *	Writes a packet as immediate data into a Tx descriptor.  The packet
+ *	contains a work request at its beginning.  We must write the packet
+ *	carefully so the SGE doesn't read accidentally before it's written in
+ *	its entirety.
+ */
+static inline void write_imm(struct tx_desc *d, struct sk_buff *skb,
+			     unsigned int len, unsigned int gen)
+{
+	struct work_request_hdr *from = (struct work_request_hdr *)skb->data;
+	struct work_request_hdr *to = (struct work_request_hdr *)d;
+
+	memcpy(&to[1], &from[1], len - sizeof(*from));
+	to->wr_hi = from->wr_hi | htonl(F_WR_SOP | F_WR_EOP |
+					V_WR_BCNTLFLT(len & 7));
+	wmb();
+	to->wr_lo = from->wr_lo | htonl(V_WR_GEN(gen) |
+					V_WR_LEN((len + 7) / 8));
+	wr_gen2(d, gen);
+	kfree_skb(skb);
+}
+
+/**
+ *	check_desc_avail - check descriptor availability on a send queue
+ *	@adap: the adapter
+ *	@q: the send queue
+ *	@skb: the packet needing the descriptors
+ *	@ndesc: the number of Tx descriptors needed
+ *	@qid: the Tx queue number in its queue set (TXQ_OFLD or TXQ_CTRL)
+ *
+ *	Checks if the requested number of Tx descriptors is available on an
+ *	SGE send queue.  If the queue is already suspended or not enough
+ *	descriptors are available the packet is queued for later transmission.
+ *	Must be called with the Tx queue locked.
+ *
+ *	Returns 0 if enough descriptors are available, 1 if there aren't
+ *	enough descriptors and the packet has been queued, and 2 if the caller
+ *	needs to retry because there weren't enough descriptors at the
+ *	beginning of the call but some freed up in the mean time.
+ */
+static inline int check_desc_avail(struct adapter *adap, struct sge_txq *q,
+				   struct sk_buff *skb, unsigned int ndesc,
+				   unsigned int qid)
+{
+	if (unlikely(!skb_queue_empty(&q->sendq))) {
+	      addq_exit:__skb_queue_tail(&q->sendq, skb);
+		return 1;
+	}
+	if (unlikely(q->size - q->in_use < ndesc)) {
+		struct sge_qset *qs = txq_to_qset(q, qid);
+
+		set_bit(qid, &qs->txq_stopped);
+		smp_mb__after_clear_bit();
+
+		if (should_restart_tx(q) &&
+		    test_and_clear_bit(qid, &qs->txq_stopped))
+			return 2;
+
+		q->stops++;
+		goto addq_exit;
+	}
+	return 0;
+}
+
+/**
+ *	reclaim_completed_tx_imm - reclaim completed control-queue Tx descs
+ *	@q: the SGE control Tx queue
+ *
+ *	This is a variant of reclaim_completed_tx() that is used for Tx queues
+ *	that send only immediate data (presently just the control queues) and
+ *	thus do not have any sk_buffs to release.
+ */
+static inline void reclaim_completed_tx_imm(struct sge_txq *q)
+{
+	unsigned int reclaim = q->processed - q->cleaned;
+
+	q->in_use -= reclaim;
+	q->cleaned += reclaim;
+}
+
+static inline int immediate(const struct sk_buff *skb)
+{
+	return skb->len <= WR_LEN && !skb->data_len;
+}
+
+/**
+ *	ctrl_xmit - send a packet through an SGE control Tx queue
+ *	@adap: the adapter
+ *	@q: the control queue
+ *	@skb: the packet
+ *
+ *	Send a packet through an SGE control Tx queue.  Packets sent through
+ *	a control queue must fit entirely as immediate data in a single Tx
+ *	descriptor and have no page fragments.
+ */
+static int ctrl_xmit(struct adapter *adap, struct sge_txq *q,
+		     struct sk_buff *skb)
+{
+	int ret;
+	struct work_request_hdr *wrp = (struct work_request_hdr *)skb->data;
+
+	if (unlikely(!immediate(skb))) {
+		WARN_ON(1);
+		dev_kfree_skb(skb);
+		return NET_XMIT_SUCCESS;
+	}
+
+	wrp->wr_hi |= htonl(F_WR_SOP | F_WR_EOP);
+	wrp->wr_lo = htonl(V_WR_TID(q->token));
+
+	spin_lock(&q->lock);
+      again:reclaim_completed_tx_imm(q);
+
+	ret = check_desc_avail(adap, q, skb, 1, TXQ_CTRL);
+	if (unlikely(ret)) {
+		if (ret == 1) {
+			spin_unlock(&q->lock);
+			return NET_XMIT_CN;
+		}
+		goto again;
+	}
+
+	write_imm(&q->desc[q->pidx], skb, skb->len, q->gen);
+
+	q->in_use++;
+	if (++q->pidx >= q->size) {
+		q->pidx = 0;
+		q->gen ^= 1;
+	}
+	spin_unlock(&q->lock);
+	wmb();
+	t3_write_reg(adap, A_SG_KDOORBELL,
+		     F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
+	return NET_XMIT_SUCCESS;
+}
+
+/**
+ *	restart_ctrlq - restart a suspended control queue
+ *	@qs: the queue set cotaining the control queue
+ *
+ *	Resumes transmission on a suspended Tx control queue.
+ */
+static void restart_ctrlq(unsigned long data)
+{
+	struct sk_buff *skb;
+	struct sge_qset *qs = (struct sge_qset *)data;
+	struct sge_txq *q = &qs->txq[TXQ_CTRL];
+	struct adapter *adap = qs->netdev->priv;
+
+	spin_lock(&q->lock);
+      again:reclaim_completed_tx_imm(q);
+
+	while (q->in_use < q->size && (skb = __skb_dequeue(&q->sendq)) != NULL) {
+
+		write_imm(&q->desc[q->pidx], skb, skb->len, q->gen);
+
+		if (++q->pidx >= q->size) {
+			q->pidx = 0;
+			q->gen ^= 1;
+		}
+		q->in_use++;
+	}
+
+	if (!skb_queue_empty(&q->sendq)) {
+		set_bit(TXQ_CTRL, &qs->txq_stopped);
+		smp_mb__after_clear_bit();
+
+		if (should_restart_tx(q) &&
+		    test_and_clear_bit(TXQ_CTRL, &qs->txq_stopped))
+			goto again;
+		q->stops++;
+	}
+
+	spin_unlock(&q->lock);
+	t3_write_reg(adap, A_SG_KDOORBELL,
+		     F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
+}
+
+/**
+ *	write_ofld_wr - write an offload work request
+ *	@adap: the adapter
+ *	@skb: the packet to send
+ *	@q: the Tx queue
+ *	@pidx: index of the first Tx descriptor to write
+ *	@gen: the generation value to use
+ *	@ndesc: number of descriptors the packet will occupy
+ *
+ *	Write an offload work request to send the supplied packet.  The packet
+ *	data already carry the work request with most fields populated.
+ */
+static void write_ofld_wr(struct adapter *adap, struct sk_buff *skb,
+			  struct sge_txq *q, unsigned int pidx,
+			  unsigned int gen, unsigned int ndesc)
+{
+	unsigned int sgl_flits, flits;
+	struct work_request_hdr *from;
+	struct sg_ent *sgp, sgl[MAX_SKB_FRAGS / 2 + 1];
+	struct tx_desc *d = &q->desc[pidx];
+
+	if (immediate(skb)) {
+		q->sdesc[pidx].skb = NULL;
+		write_imm(d, skb, skb->len, gen);
+		return;
+	}
+
+	/* Only TX_DATA builds SGLs */
+
+	from = (struct work_request_hdr *)skb->data;
+	memcpy(&d->flit[1], &from[1], skb->h.raw - skb->data - sizeof(*from));
+
+	flits = (skb->h.raw - skb->data) / 8;
+	sgp = ndesc == 1 ? (struct sg_ent *)&d->flit[flits] : sgl;
+	sgl_flits = make_sgl(skb, sgp, skb->h.raw, skb->tail - skb->h.raw,
+			     adap->pdev);
+	if (need_skb_unmap())
+		((struct unmap_info *)skb->cb)->len = skb->tail - skb->h.raw;
+
+	write_wr_hdr_sgl(ndesc, skb, d, pidx, q, sgl, flits, sgl_flits,
+			 gen, from->wr_hi, from->wr_lo);
+}
+
+/**
+ *	calc_tx_descs_ofld - calculate # of Tx descriptors for an offload packet
+ *	@skb: the packet
+ *
+ * 	Returns the number of Tx descriptors needed for the given offload
+ * 	packet.  These packets are already fully constructed.
+ */
+static inline unsigned int calc_tx_descs_ofld(const struct sk_buff *skb)
+{
+	unsigned int flits, cnt = skb_shinfo(skb)->nr_frags;
+
+	if (skb->len <= WR_LEN && cnt == 0)
+		return 1;	/* packet fits as immediate data */
+
+	flits = (skb->h.raw - skb->data) / 8;	/* headers */
+	if (skb->tail != skb->h.raw)
+		cnt++;
+	return flits_to_desc(flits + sgl_len(cnt));
+}
+
+/**
+ *	ofld_xmit - send a packet through an offload queue
+ *	@adap: the adapter
+ *	@q: the Tx offload queue
+ *	@skb: the packet
+ *
+ *	Send an offload packet through an SGE offload queue.
+ */
+static int ofld_xmit(struct adapter *adap, struct sge_txq *q,
+		     struct sk_buff *skb)
+{
+	int ret;
+	unsigned int ndesc = calc_tx_descs_ofld(skb), pidx, gen;
+
+	spin_lock(&q->lock);
+      again:reclaim_completed_tx(adap, q);
+
+	ret = check_desc_avail(adap, q, skb, ndesc, TXQ_OFLD);
+	if (unlikely(ret)) {
+		if (ret == 1) {
+			skb->priority = ndesc;	/* save for restart */
+			spin_unlock(&q->lock);
+			return NET_XMIT_CN;
+		}
+		goto again;
+	}
+
+	gen = q->gen;
+	q->in_use += ndesc;
+	pidx = q->pidx;
+	q->pidx += ndesc;
+	if (q->pidx >= q->size) {
+		q->pidx -= q->size;
+		q->gen ^= 1;
+	}
+	spin_unlock(&q->lock);
+
+	write_ofld_wr(adap, skb, q, pidx, gen, ndesc);
+	check_ring_tx_db(adap, q);
+	return NET_XMIT_SUCCESS;
+}
+
+/**
+ *	restart_offloadq - restart a suspended offload queue
+ *	@qs: the queue set cotaining the offload queue
+ *
+ *	Resumes transmission on a suspended Tx offload queue.
+ */
+static void restart_offloadq(unsigned long data)
+{
+	struct sk_buff *skb;
+	struct sge_qset *qs = (struct sge_qset *)data;
+	struct sge_txq *q = &qs->txq[TXQ_OFLD];
+	struct adapter *adap = qs->netdev->priv;
+
+	spin_lock(&q->lock);
+      again:reclaim_completed_tx(adap, q);
+
+	while ((skb = skb_peek(&q->sendq)) != NULL) {
+		unsigned int gen, pidx;
+		unsigned int ndesc = skb->priority;
+
+		if (unlikely(q->size - q->in_use < ndesc)) {
+			set_bit(TXQ_OFLD, &qs->txq_stopped);
+			smp_mb__after_clear_bit();
+
+			if (should_restart_tx(q) &&
+			    test_and_clear_bit(TXQ_OFLD, &qs->txq_stopped))
+				goto again;
+			q->stops++;
+			break;
+		}
+
+		gen = q->gen;
+		q->in_use += ndesc;
+		pidx = q->pidx;
+		q->pidx += ndesc;
+		if (q->pidx >= q->size) {
+			q->pidx -= q->size;
+			q->gen ^= 1;
+		}
+		__skb_unlink(skb, &q->sendq);
+		spin_unlock(&q->lock);
+
+		write_ofld_wr(adap, skb, q, pidx, gen, ndesc);
+		spin_lock(&q->lock);
+	}
+	spin_unlock(&q->lock);
+
+#if USE_GTS
+	set_bit(TXQ_RUNNING, &q->flags);
+	set_bit(TXQ_LAST_PKT_DB, &q->flags);
+#endif
+	t3_write_reg(adap, A_SG_KDOORBELL,
+		     F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
+}
+
+/**
+ *	queue_set - return the queue set a packet should use
+ *	@skb: the packet
+ *
+ *	Maps a packet to the SGE queue set it should use.  The desired queue
+ *	set is carried in bits 1-3 in the packet's priority.
+ */
+static inline int queue_set(const struct sk_buff *skb)
+{
+	return skb->priority >> 1;
+}
+
+/**
+ *	is_ctrl_pkt - return whether an offload packet is a control packet
+ *	@skb: the packet
+ *
+ *	Determines whether an offload packet should use an OFLD or a CTRL
+ *	Tx queue.  This is indicated by bit 0 in the packet's priority.
+ */
+static inline int is_ctrl_pkt(const struct sk_buff *skb)
+{
+	return skb->priority & 1;
+}
+
+/**
+ *	t3_offload_tx - send an offload packet
+ *	@tdev: the offload device to send to
+ *	@skb: the packet
+ *
+ *	Sends an offload packet.  We use the packet priority to select the
+ *	appropriate Tx queue as follows: bit 0 indicates whether the packet
+ *	should be sent as regular or control, bits 1-3 select the queue set.
+ */
+int t3_offload_tx(struct t3cdev *tdev, struct sk_buff *skb)
+{
+	struct adapter *adap = tdev2adap(tdev);
+	struct sge_qset *qs = &adap->sge.qs[queue_set(skb)];
+
+	if (unlikely(is_ctrl_pkt(skb)))
+		return ctrl_xmit(adap, &qs->txq[TXQ_CTRL], skb);
+
+	return ofld_xmit(adap, &qs->txq[TXQ_OFLD], skb);
+}
+
+/**
+ *	offload_enqueue - add an offload packet to an SGE offload receive queue
+ *	@q: the SGE response queue
+ *	@skb: the packet
+ *
+ *	Add a new offload packet to an SGE response queue's offload packet
+ *	queue.  If the packet is the first on the queue it schedules the RX
+ *	softirq to process the queue.
+ */
+static inline void offload_enqueue(struct sge_rspq *q, struct sk_buff *skb)
+{
+	skb->next = skb->prev = NULL;
+	if (q->rx_tail)
+		q->rx_tail->next = skb;
+	else {
+		struct sge_qset *qs = rspq_to_qset(q);
+
+		if (__netif_rx_schedule_prep(qs->netdev))
+			__netif_rx_schedule(qs->netdev);
+		q->rx_head = skb;
+	}
+	q->rx_tail = skb;
+}
+
+/**
+ *	deliver_partial_bundle - deliver a (partial) bundle of Rx offload pkts
+ *	@tdev: the offload device that will be receiving the packets
+ *	@q: the SGE response queue that assembled the bundle
+ *	@skbs: the partial bundle
+ *	@n: the number of packets in the bundle
+ *
+ *	Delivers a (partial) bundle of Rx offload packets to an offload device.
+ */
+static inline void deliver_partial_bundle(struct t3cdev *tdev,
+					  struct sge_rspq *q,
+					  struct sk_buff *skbs[], int n)
+{
+	if (n) {
+		q->offload_bundles++;
+		tdev->recv(tdev, skbs, n);
+	}
+}
+
+/**
+ *	ofld_poll - NAPI handler for offload packets in interrupt mode
+ *	@dev: the network device doing the polling
+ *	@budget: polling budget
+ *
+ *	The NAPI handler for offload packets when a response queue is serviced
+ *	by the hard interrupt handler, i.e., when it's operating in non-polling
+ *	mode.  Creates small packet batches and sends them through the offload
+ *	receive handler.  Batches need to be of modest size as we do prefetches
+ *	on the packets in each.
+ */
+static int ofld_poll(struct net_device *dev, int *budget)
+{
+	struct adapter *adapter = dev->priv;
+	struct sge_qset *qs = dev2qset(dev);
+	struct sge_rspq *q = &qs->rspq;
+	int work_done, limit = min(*budget, dev->quota), avail = limit;
+
+	while (avail) {
+		struct sk_buff *head, *tail, *skbs[RX_BUNDLE_SIZE];
+		int ngathered;
+
+		spin_lock_irq(&q->lock);
+		head = q->rx_head;
+		if (!head) {
+			work_done = limit - avail;
+			*budget -= work_done;
+			dev->quota -= work_done;
+			__netif_rx_complete(dev);
+			spin_unlock_irq(&q->lock);
+			return 0;
+		}
+
+		tail = q->rx_tail;
+		q->rx_head = q->rx_tail = NULL;
+		spin_unlock_irq(&q->lock);
+
+		for (ngathered = 0; avail && head; avail--) {
+			prefetch(head->data);
+			skbs[ngathered] = head;
+			head = head->next;
+			skbs[ngathered]->next = NULL;
+			if (++ngathered == RX_BUNDLE_SIZE) {
+				q->offload_bundles++;
+				adapter->tdev.recv(&adapter->tdev, skbs,
+						   ngathered);
+				ngathered = 0;
+			}
+		}
+		if (head) {	/* splice remaining packets back onto Rx queue */
+			spin_lock_irq(&q->lock);
+			tail->next = q->rx_head;
+			if (!q->rx_head)
+				q->rx_tail = tail;
+			q->rx_head = head;
+			spin_unlock_irq(&q->lock);
+		}
+		deliver_partial_bundle(&adapter->tdev, q, skbs, ngathered);
+	}
+	work_done = limit - avail;
+	*budget -= work_done;
+	dev->quota -= work_done;
+	return 1;
+}
+
+/**
+ *	rx_offload - process a received offload packet
+ *	@tdev: the offload device receiving the packet
+ *	@rq: the response queue that received the packet
+ *	@skb: the packet
+ *	@rx_gather: a gather list of packets if we are building a bundle
+ *	@gather_idx: index of the next available slot in the bundle
+ *
+ *	Process an ingress offload pakcet and add it to the offload ingress
+ *	queue. 	Returns the index of the next available slot in the bundle.
+ */
+static inline int rx_offload(struct t3cdev *tdev, struct sge_rspq *rq,
+			     struct sk_buff *skb, struct sk_buff *rx_gather[],
+			     unsigned int gather_idx)
+{
+	rq->offload_pkts++;
+	skb->mac.raw = skb->nh.raw = skb->h.raw = skb->data;
+
+	if (rq->polling) {
+		rx_gather[gather_idx++] = skb;
+		if (gather_idx == RX_BUNDLE_SIZE) {
+			tdev->recv(tdev, rx_gather, RX_BUNDLE_SIZE);
+			gather_idx = 0;
+			rq->offload_bundles++;
+		}
+	} else
+		offload_enqueue(rq, skb);
+
+	return gather_idx;
+}
+
+/**
+ *	update_tx_completed - update the number of processed Tx descriptors
+ *	@qs: the queue set to update
+ *	@idx: which Tx queue within the set to update
+ *	@credits: number of new processed descriptors
+ *	@tx_completed: accumulates credits for the queues
+ *
+ *	Updates the number of completed Tx descriptors for a queue set's Tx
+ *	queue.  On UP systems we updated the information immediately but on
+ *	MP we accumulate the credits locally and update the Tx queue when we
+ *	reach a threshold to avoid cache-line bouncing.
+ */
+static inline void update_tx_completed(struct sge_qset *qs, int idx,
+				       unsigned int credits,
+				       unsigned int tx_completed[])
+{
+#ifdef CONFIG_SMP
+	tx_completed[idx] += credits;
+	if (tx_completed[idx] > 32) {
+		qs->txq[idx].processed += tx_completed[idx];
+		tx_completed[idx] = 0;
+	}
+#else
+	qs->txq[idx].processed += credits;
+#endif
+}
+
+/**
+ *	restart_tx - check whether to restart suspended Tx queues
+ *	@qs: the queue set to resume
+ *
+ *	Restarts suspended Tx queues of an SGE queue set if they have enough
+ *	free resources to resume operation.
+ */
+static void restart_tx(struct sge_qset *qs)
+{
+	if (test_bit(TXQ_ETH, &qs->txq_stopped) &&
+	    should_restart_tx(&qs->txq[TXQ_ETH]) &&
+	    test_and_clear_bit(TXQ_ETH, &qs->txq_stopped)) {
+		qs->txq[TXQ_ETH].restarts++;
+		if (netif_running(qs->netdev))
+			netif_wake_queue(qs->netdev);
+	}
+
+	if (test_bit(TXQ_OFLD, &qs->txq_stopped) &&
+	    should_restart_tx(&qs->txq[TXQ_OFLD]) &&
+	    test_and_clear_bit(TXQ_OFLD, &qs->txq_stopped)) {
+		qs->txq[TXQ_OFLD].restarts++;
+		tasklet_schedule(&qs->txq[TXQ_OFLD].qresume_tsk);
+	}
+	if (test_bit(TXQ_CTRL, &qs->txq_stopped) &&
+	    should_restart_tx(&qs->txq[TXQ_CTRL]) &&
+	    test_and_clear_bit(TXQ_CTRL, &qs->txq_stopped)) {
+		qs->txq[TXQ_CTRL].restarts++;
+		tasklet_schedule(&qs->txq[TXQ_CTRL].qresume_tsk);
+	}
+}
+
+/**
+ *	rx_eth - process an ingress ethernet packet
+ *	@adap: the adapter
+ *	@rq: the response queue that received the packet
+ *	@skb: the packet
+ *	@pad: amount of padding at the start of the buffer
+ *
+ *	Process an ingress ethernet pakcet and deliver it to the stack.
+ *	The padding is 2 if the packet was delivered in an Rx buffer and 0
+ *	if it was immediate data in a response.
+ */
+static void rx_eth(struct adapter *adap, struct sge_rspq *rq,
+		   struct sk_buff *skb, int pad)
+{
+	struct cpl_rx_pkt *p = (struct cpl_rx_pkt *)(skb->data + pad);
+	struct port_info *pi;
+
+	rq->eth_pkts++;
+	skb_pull(skb, sizeof(*p) + pad);
+	skb->dev = adap->port[p->iff];
+	skb->dev->last_rx = jiffies;
+	skb->protocol = eth_type_trans(skb, skb->dev);
+	pi = netdev_priv(skb->dev);
+	if (pi->rx_csum_offload && p->csum_valid && p->csum == 0xffff &&
+	    !p->fragment) {
+		rspq_to_qset(rq)->port_stats[SGE_PSTAT_RX_CSUM_GOOD]++;
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
+	} else
+		skb->ip_summed = CHECKSUM_NONE;
+
+	if (unlikely(p->vlan_valid)) {
+		struct vlan_group *grp = pi->vlan_grp;
+
+		rspq_to_qset(rq)->port_stats[SGE_PSTAT_VLANEX]++;
+		if (likely(grp))
+			__vlan_hwaccel_rx(skb, grp, ntohs(p->vlan),
+					  rq->polling);
+		else
+			dev_kfree_skb_any(skb);
+	} else if (rq->polling)
+		netif_receive_skb(skb);
+	else
+		netif_rx(skb);
+}
+
+/**
+ *	handle_rsp_cntrl_info - handles control information in a response
+ *	@qs: the queue set corresponding to the response
+ *	@flags: the response control flags
+ *	@tx_completed: accumulates completion credits for the Tx queues
+ *
+ *	Handles the control information of an SGE response, such as GTS
+ *	indications and completion credits for the queue set's Tx queues.
+ */
+static inline void handle_rsp_cntrl_info(struct sge_qset *qs, u32 flags,
+					 unsigned int tx_completed[])
+{
+	unsigned int credits;
+
+#if USE_GTS
+	if (flags & F_RSPD_TXQ0_GTS)
+		clear_bit(TXQ_RUNNING, &qs->txq[TXQ_ETH].flags);
+#endif
+
+	/* ETH credits are already coalesced, return them immediately. */
+	credits = G_RSPD_TXQ0_CR(flags);
+	if (credits)
+		qs->txq[TXQ_ETH].processed += credits;
+
+# if USE_GTS
+	if (flags & F_RSPD_TXQ1_GTS)
+		clear_bit(TXQ_RUNNING, &qs->txq[TXQ_OFLD].flags);
+# endif
+	update_tx_completed(qs, TXQ_OFLD, G_RSPD_TXQ1_CR(flags), tx_completed);
+	update_tx_completed(qs, TXQ_CTRL, G_RSPD_TXQ2_CR(flags), tx_completed);
+}
+
+/**
+ *	flush_tx_completed - returns accumulated Tx completions to Tx queues
+ *	@qs: the queue set to update
+ *	@tx_completed: pending completion credits to return to Tx queues
+ *
+ *	Updates the number of completed Tx descriptors for a queue set's Tx
+ *	queues with the credits pending in @tx_completed.  This does something
+ *	only on MP systems as on UP systems we return the credits immediately.
+ */
+static inline void flush_tx_completed(struct sge_qset *qs,
+				      unsigned int tx_completed[])
+{
+#if defined(CONFIG_SMP)
+	if (tx_completed[TXQ_OFLD])
+		qs->txq[TXQ_OFLD].processed += tx_completed[TXQ_OFLD];
+	if (tx_completed[TXQ_CTRL])
+		qs->txq[TXQ_CTRL].processed += tx_completed[TXQ_CTRL];
+#endif
+}
+
+/**
+ *	check_ring_db - check if we need to ring any doorbells
+ *	@adapter: the adapter
+ *	@qs: the queue set whose Tx queues are to be examined
+ *	@sleeping: indicates which Tx queue sent GTS
+ *
+ *	Checks if some of a queue set's Tx queues need to ring their doorbells
+ *	to resume transmission after idling while they still have unprocessed
+ *	descriptors.
+ */
+static void check_ring_db(struct adapter *adap, struct sge_qset *qs,
+			  unsigned int sleeping)
+{
+	if (sleeping & F_RSPD_TXQ0_GTS) {
+		struct sge_txq *txq = &qs->txq[TXQ_ETH];
+
+		if (txq->cleaned + txq->in_use != txq->processed &&
+		    !test_and_set_bit(TXQ_LAST_PKT_DB, &txq->flags)) {
+			set_bit(TXQ_RUNNING, &txq->flags);
+			t3_write_reg(adap, A_SG_KDOORBELL, F_SELEGRCNTX |
+				     V_EGRCNTX(txq->cntxt_id));
+		}
+	}
+
+	if (sleeping & F_RSPD_TXQ1_GTS) {
+		struct sge_txq *txq = &qs->txq[TXQ_OFLD];
+
+		if (txq->cleaned + txq->in_use != txq->processed &&
+		    !test_and_set_bit(TXQ_LAST_PKT_DB, &txq->flags)) {
+			set_bit(TXQ_RUNNING, &txq->flags);
+			t3_write_reg(adap, A_SG_KDOORBELL, F_SELEGRCNTX |
+				     V_EGRCNTX(txq->cntxt_id));
+		}
+	}
+}
+
+/**
+ *	is_new_response - check if a response is newly written
+ *	@r: the response descriptor
+ *	@q: the response queue
+ *
+ *	Returns true if a response descriptor contains a yet unprocessed
+ *	response.
+ */
+static inline int is_new_response(const struct rsp_desc *r,
+				  const struct sge_rspq *q)
+{
+	return (r->intr_gen & F_RSPD_GEN2) == q->gen;
+}
+
+#define RSPD_GTS_MASK  (F_RSPD_TXQ0_GTS | F_RSPD_TXQ1_GTS)
+#define RSPD_CTRL_MASK (RSPD_GTS_MASK | \
+			V_RSPD_TXQ0_CR(M_RSPD_TXQ0_CR) | \
+			V_RSPD_TXQ1_CR(M_RSPD_TXQ1_CR) | \
+			V_RSPD_TXQ2_CR(M_RSPD_TXQ2_CR))
+
+/* How long to delay the next interrupt in case of memory shortage, in 0.1us. */
+#define NOMEM_INTR_DELAY 2500
+
+/**
+ *	process_responses - process responses from an SGE response queue
+ *	@adap: the adapter
+ *	@qs: the queue set to which the response queue belongs
+ *	@budget: how many responses can be processed in this round
+ *
+ *	Process responses from an SGE response queue up to the supplied budget.
+ *	Responses include received packets as well as credits and other events
+ *	for the queues that belong to the response queue's queue set.
+ *	A negative budget is effectively unlimited.
+ *
+ *	Additionally choose the interrupt holdoff time for the next interrupt
+ *	on this queue.  If the system is under memory shortage use a fairly
+ *	long delay to help recovery.
+ */
+static int process_responses(struct adapter *adap, struct sge_qset *qs,
+			     int budget)
+{
+	struct sge_rspq *q = &qs->rspq;
+	struct rsp_desc *r = &q->desc[q->cidx];
+	int budget_left = budget;
+	unsigned int sleeping = 0, tx_completed[3] = { 0, 0, 0 };
+	struct sk_buff *offload_skbs[RX_BUNDLE_SIZE];
+	int ngathered = 0;
+
+	q->next_holdoff = q->holdoff_tmr;
+
+	while (likely(budget_left && is_new_response(r, q))) {
+		int eth, ethpad = 0;
+		struct sk_buff *skb = NULL;
+		u32 len, flags = ntohl(r->flags);
+		u32 rss_hi = *(const u32 *)r, rss_lo = r->rss_hdr.rss_hash_val;
+
+		eth = r->rss_hdr.opcode == CPL_RX_PKT;
+
+		if (unlikely(flags & F_RSPD_ASYNC_NOTIF)) {
+			skb = alloc_skb(AN_PKT_SIZE, GFP_ATOMIC);
+			if (!skb)
+				goto no_mem;
+
+			memcpy(__skb_put(skb, AN_PKT_SIZE), r, AN_PKT_SIZE);
+			skb->data[0] = CPL_ASYNC_NOTIF;
+			rss_hi = htonl(CPL_ASYNC_NOTIF << 24);
+			q->async_notif++;
+		} else if (flags & F_RSPD_IMM_DATA_VALID) {
+			skb = get_imm_packet(r);
+			if (unlikely(!skb)) {
+			      no_mem:
+				q->next_holdoff = NOMEM_INTR_DELAY;
+				q->nomem++;
+				/* consume one credit since we tried */
+				budget_left--;
+				break;
+			}
+			q->imm_data++;
+		} else if ((len = ntohl(r->len_cq)) != 0) {
+			struct sge_fl *fl;
+
+			fl = (len & F_RSPD_FLQ) ? &qs->fl[1] : &qs->fl[0];
+			fl->credits--;
+			skb = get_packet(adap, fl, G_RSPD_LEN(len),
+					 eth ? SGE_RX_DROP_THRES : 0);
+			if (!skb)
+				q->rx_drops++;
+			else if (r->rss_hdr.opcode == CPL_TRACE_PKT)
+				__skb_pull(skb, 2);
+			ethpad = 2;
+			if (++fl->cidx == fl->size)
+				fl->cidx = 0;
+		} else
+			q->pure_rsps++;
+
+		if (flags & RSPD_CTRL_MASK) {
+			sleeping |= flags & RSPD_GTS_MASK;
+			handle_rsp_cntrl_info(qs, flags, tx_completed);
+		}
+
+		r++;
+		if (unlikely(++q->cidx == q->size)) {
+			q->cidx = 0;
+			q->gen ^= 1;
+			r = q->desc;
+		}
+		prefetch(r);
+
+		if (++q->credits >= (q->size / 4)) {
+			refill_rspq(adap, q, q->credits);
+			q->credits = 0;
+		}
+
+		if (likely(skb != NULL)) {
+			if (eth)
+				rx_eth(adap, q, skb, ethpad);
+			else {
+				/* Preserve the RSS info in csum & priority */
+				skb->csum = rss_hi;
+				skb->priority = rss_lo;
+				ngathered = rx_offload(&adap->tdev, q, skb,
+						       offload_skbs, ngathered);
+			}
+		}
+
+		--budget_left;
+	}
+
+	flush_tx_completed(qs, tx_completed);
+	deliver_partial_bundle(&adap->tdev, q, offload_skbs, ngathered);
+	if (sleeping)
+		check_ring_db(adap, qs, sleeping);
+
+	smp_mb();		/* commit Tx queue .processed updates */
+	if (unlikely(qs->txq_stopped != 0))
+		restart_tx(qs);
+
+	budget -= budget_left;
+	return budget;
+}
+
+static inline int is_pure_response(const struct rsp_desc *r)
+{
+	u32 n = ntohl(r->flags) & (F_RSPD_ASYNC_NOTIF | F_RSPD_IMM_DATA_VALID);
+
+	return (n | r->len_cq) == 0;
+}
+
+/**
+ *	napi_rx_handler - the NAPI handler for Rx processing
+ *	@dev: the net device
+ *	@budget: how many packets we can process in this round
+ *
+ *	Handler for new data events when using NAPI.
+ */
+static int napi_rx_handler(struct net_device *dev, int *budget)
+{
+	struct adapter *adap = dev->priv;
+	struct sge_qset *qs = dev2qset(dev);
+	int effective_budget = min(*budget, dev->quota);
+
+	int work_done = process_responses(adap, qs, effective_budget);
+	*budget -= work_done;
+	dev->quota -= work_done;
+
+	if (work_done >= effective_budget)
+		return 1;
+
+	netif_rx_complete(dev);
+
+	/*
+	 * Because we don't atomically flush the following write it is
+	 * possible that in very rare cases it can reach the device in a way
+	 * that races with a new response being written plus an error interrupt
+	 * causing the NAPI interrupt handler below to return unhandled status
+	 * to the OS.  To protect against this would require flushing the write
+	 * and doing both the write and the flush with interrupts off.  Way too
+	 * expensive and unjustifiable given the rarity of the race.
+	 *
+	 * The race cannot happen at all with MSI-X.
+	 */
+	t3_write_reg(adap, A_SG_GTS, V_RSPQ(qs->rspq.cntxt_id) |
+		     V_NEWTIMER(qs->rspq.next_holdoff) |
+		     V_NEWINDEX(qs->rspq.cidx));
+	return 0;
+}
+
+/*
+ * Returns true if the device is already scheduled for polling.
+ */
+static inline int napi_is_scheduled(struct net_device *dev)
+{
+	return test_bit(__LINK_STATE_RX_SCHED, &dev->state);
+}
+
+/**
+ *	process_pure_responses - process pure responses from a response queue
+ *	@adap: the adapter
+ *	@qs: the queue set owning the response queue
+ *	@r: the first pure response to process
+ *
+ *	A simpler version of process_responses() that handles only pure (i.e.,
+ *	non data-carrying) responses.  Such respones are too light-weight to
+ *	justify calling a softirq under NAPI, so we handle them specially in
+ *	the interrupt handler.  The function is called with a pointer to a
+ *	response, which the caller must ensure is a valid pure response.
+ *
+ *	Returns 1 if it encounters a valid data-carrying response, 0 otherwise.
+ */
+static int process_pure_responses(struct adapter *adap, struct sge_qset *qs,
+				  struct rsp_desc *r)
+{
+	struct sge_rspq *q = &qs->rspq;
+	unsigned int sleeping = 0, tx_completed[3] = { 0, 0, 0 };
+
+	do {
+		u32 flags = ntohl(r->flags);
+
+		r++;
+		if (unlikely(++q->cidx == q->size)) {
+			q->cidx = 0;
+			q->gen ^= 1;
+			r = q->desc;
+		}
+		prefetch(r);
+
+		if (flags & RSPD_CTRL_MASK) {
+			sleeping |= flags & RSPD_GTS_MASK;
+			handle_rsp_cntrl_info(qs, flags, tx_completed);
+		}
+
+		q->pure_rsps++;
+		if (++q->credits >= (q->size / 4)) {
+			refill_rspq(adap, q, q->credits);
+			q->credits = 0;
+		}
+	} while (is_new_response(r, q) && is_pure_response(r));
+
+	flush_tx_completed(qs, tx_completed);
+
+	if (sleeping)
+		check_ring_db(adap, qs, sleeping);
+
+	smp_mb();		/* commit Tx queue .processed updates */
+	if (unlikely(qs->txq_stopped != 0))
+		restart_tx(qs);
+
+	return is_new_response(r, q);
+}
+
+/**
+ *	handle_responses - decide what to do with new responses in NAPI mode
+ *	@adap: the adapter
+ *	@q: the response queue
+ *
+ *	This is used by the NAPI interrupt handlers to decide what to do with
+ *	new SGE responses.  If there are no new responses it returns -1.  If
+ *	there are new responses and they are pure (i.e., non-data carrying)
+ *	it handles them straight in hard interrupt context as they are very
+ *	cheap and don't deliver any packets.  Finally, if there are any data
+ *	signaling responses it schedules the NAPI handler.  Returns 1 if it
+ *	schedules NAPI, 0 if all new responses were pure.
+ *
+ *	The caller must ascertain NAPI is not already running.
+ */
+static inline int handle_responses(struct adapter *adap, struct sge_rspq *q)
+{
+	struct sge_qset *qs = rspq_to_qset(q);
+	struct rsp_desc *r = &q->desc[q->cidx];
+
+	if (!is_new_response(r, q))
+		return -1;
+	if (is_pure_response(r) && process_pure_responses(adap, qs, r) == 0) {
+		t3_write_reg(adap, A_SG_GTS, V_RSPQ(q->cntxt_id) |
+			     V_NEWTIMER(q->holdoff_tmr) | V_NEWINDEX(q->cidx));
+		return 0;
+	}
+	if (likely(__netif_rx_schedule_prep(qs->netdev)))
+		__netif_rx_schedule(qs->netdev);
+	return 1;
+}
+
+/*
+ * The MSI-X interrupt handler for an SGE response queue for the non-NAPI case
+ * (i.e., response queue serviced in hard interrupt).
+ */
+irqreturn_t t3_sge_intr_msix(int irq, void *cookie)
+{
+	struct sge_qset *qs = cookie;
+	struct adapter *adap = qs->netdev->priv;
+	struct sge_rspq *q = &qs->rspq;
+
+	spin_lock(&q->lock);
+	if (process_responses(adap, qs, -1) == 0)
+		q->unhandled_irqs++;
+	t3_write_reg(adap, A_SG_GTS, V_RSPQ(q->cntxt_id) |
+		     V_NEWTIMER(q->next_holdoff) | V_NEWINDEX(q->cidx));
+	spin_unlock(&q->lock);
+	return IRQ_HANDLED;
+}
+
+/*
+ * The MSI-X interrupt handler for an SGE response queue for the NAPI case
+ * (i.e., response queue serviced by NAPI polling).
+ */
+irqreturn_t t3_sge_intr_msix_napi(int irq, void *cookie)
+{
+	struct sge_qset *qs = cookie;
+	struct adapter *adap = qs->netdev->priv;
+	struct sge_rspq *q = &qs->rspq;
+
+	spin_lock(&q->lock);
+	BUG_ON(napi_is_scheduled(qs->netdev));
+
+	if (handle_responses(adap, q) < 0)
+		q->unhandled_irqs++;
+	spin_unlock(&q->lock);
+	return IRQ_HANDLED;
+}
+
+/*
+ * The non-NAPI MSI interrupt handler.  This needs to handle data events from
+ * SGE response queues as well as error and other async events as they all use
+ * the same MSI vector.  We use one SGE response queue per port in this mode
+ * and protect all response queues with queue 0's lock.
+ */
+static irqreturn_t t3_intr_msi(int irq, void *cookie)
+{
+	int new_packets = 0;
+	struct adapter *adap = cookie;
+	struct sge_rspq *q = &adap->sge.qs[0].rspq;
+
+	spin_lock(&q->lock);
+
+	if (process_responses(adap, &adap->sge.qs[0], -1)) {
+		t3_write_reg(adap, A_SG_GTS, V_RSPQ(q->cntxt_id) |
+			     V_NEWTIMER(q->next_holdoff) | V_NEWINDEX(q->cidx));
+		new_packets = 1;
+	}
+
+	if (adap->params.nports == 2 &&
+	    process_responses(adap, &adap->sge.qs[1], -1)) {
+		struct sge_rspq *q1 = &adap->sge.qs[1].rspq;
+
+		t3_write_reg(adap, A_SG_GTS, V_RSPQ(q1->cntxt_id) |
+			     V_NEWTIMER(q1->next_holdoff) |
+			     V_NEWINDEX(q1->cidx));
+		new_packets = 1;
+	}
+
+	if (!new_packets && t3_slow_intr_handler(adap) == 0)
+		q->unhandled_irqs++;
+
+	spin_unlock(&q->lock);
+	return IRQ_HANDLED;
+}
+
+static int rspq_check_napi(struct net_device *dev, struct sge_rspq *q)
+{
+	if (!napi_is_scheduled(dev) && is_new_response(&q->desc[q->cidx], q)) {
+		if (likely(__netif_rx_schedule_prep(dev)))
+			__netif_rx_schedule(dev);
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * The MSI interrupt handler for the NAPI case (i.e., response queues serviced
+ * by NAPI polling).  Handles data events from SGE response queues as well as
+ * error and other async events as they all use the same MSI vector.  We use
+ * one SGE response queue per port in this mode and protect all response
+ * queues with queue 0's lock.
+ */
+irqreturn_t t3_intr_msi_napi(int irq, void *cookie)
+{
+	int new_packets;
+	struct adapter *adap = cookie;
+	struct sge_rspq *q = &adap->sge.qs[0].rspq;
+
+	spin_lock(&q->lock);
+
+	new_packets = rspq_check_napi(adap->sge.qs[0].netdev, q);
+	if (adap->params.nports == 2)
+		new_packets += rspq_check_napi(adap->sge.qs[1].netdev,
+					       &adap->sge.qs[1].rspq);
+	if (!new_packets && t3_slow_intr_handler(adap) == 0)
+		q->unhandled_irqs++;
+
+	spin_unlock(&q->lock);
+	return IRQ_HANDLED;
+}
+
+/*
+ * A helper function that processes responses and issues GTS.
+ */
+static inline int process_responses_gts(struct adapter *adap,
+					struct sge_rspq *rq)
+{
+	int work;
+
+	work = process_responses(adap, rspq_to_qset(rq), -1);
+	t3_write_reg(adap, A_SG_GTS, V_RSPQ(rq->cntxt_id) |
+		     V_NEWTIMER(rq->next_holdoff) | V_NEWINDEX(rq->cidx));
+	return work;
+}
+
+/*
+ * The legacy INTx interrupt handler.  This needs to handle data events from
+ * SGE response queues as well as error and other async events as they all use
+ * the same interrupt pin.  We use one SGE response queue per port in this mode
+ * and protect all response queues with queue 0's lock.
+ */
+static irqreturn_t t3_intr(int irq, void *cookie)
+{
+	int work_done, w0, w1;
+	struct adapter *adap = cookie;
+	struct sge_rspq *q0 = &adap->sge.qs[0].rspq;
+	struct sge_rspq *q1 = &adap->sge.qs[1].rspq;
+
+	spin_lock(&q0->lock);
+
+	w0 = is_new_response(&q0->desc[q0->cidx], q0);
+	w1 = adap->params.nports == 2 &&
+	    is_new_response(&q1->desc[q1->cidx], q1);
+
+	if (likely(w0 | w1)) {
+		t3_write_reg(adap, A_PL_CLI, 0);
+		t3_read_reg(adap, A_PL_CLI);	/* flush */
+
+		if (likely(w0))
+			process_responses_gts(adap, q0);
+
+		if (w1)
+			process_responses_gts(adap, q1);
+
+		work_done = w0 | w1;
+	} else
+		work_done = t3_slow_intr_handler(adap);
+
+	spin_unlock(&q0->lock);
+	return IRQ_RETVAL(work_done != 0);
+}
+
+/*
+ * Interrupt handler for legacy INTx interrupts for T3B-based cards.
+ * Handles data events from SGE response queues as well as error and other
+ * async events as they all use the same interrupt pin.  We use one SGE
+ * response queue per port in this mode and protect all response queues with
+ * queue 0's lock.
+ */
+static irqreturn_t t3b_intr(int irq, void *cookie)
+{
+	u32 map;
+	struct adapter *adap = cookie;
+	struct sge_rspq *q0 = &adap->sge.qs[0].rspq;
+
+	t3_write_reg(adap, A_PL_CLI, 0);
+	map = t3_read_reg(adap, A_SG_DATA_INTR);
+
+	if (unlikely(!map))	/* shared interrupt, most likely */
+		return IRQ_NONE;
+
+	spin_lock(&q0->lock);
+
+	if (unlikely(map & F_ERRINTR))
+		t3_slow_intr_handler(adap);
+
+	if (likely(map & 1))
+		process_responses_gts(adap, q0);
+
+	if (map & 2)
+		process_responses_gts(adap, &adap->sge.qs[1].rspq);
+
+	spin_unlock(&q0->lock);
+	return IRQ_HANDLED;
+}
+
+/*
+ * NAPI interrupt handler for legacy INTx interrupts for T3B-based cards.
+ * Handles data events from SGE response queues as well as error and other
+ * async events as they all use the same interrupt pin.  We use one SGE
+ * response queue per port in this mode and protect all response queues with
+ * queue 0's lock.
+ */
+static irqreturn_t t3b_intr_napi(int irq, void *cookie)
+{
+	u32 map;
+	struct net_device *dev;
+	struct adapter *adap = cookie;
+	struct sge_rspq *q0 = &adap->sge.qs[0].rspq;
+
+	t3_write_reg(adap, A_PL_CLI, 0);
+	map = t3_read_reg(adap, A_SG_DATA_INTR);
+
+	if (unlikely(!map))	/* shared interrupt, most likely */
+		return IRQ_NONE;
+
+	spin_lock(&q0->lock);
+
+	if (unlikely(map & F_ERRINTR))
+		t3_slow_intr_handler(adap);
+
+	if (likely(map & 1)) {
+		dev = adap->sge.qs[0].netdev;
+
+		BUG_ON(napi_is_scheduled(dev));
+		if (likely(__netif_rx_schedule_prep(dev)))
+			__netif_rx_schedule(dev);
+	}
+	if (map & 2) {
+		dev = adap->sge.qs[1].netdev;
+
+		BUG_ON(napi_is_scheduled(dev));
+		if (likely(__netif_rx_schedule_prep(dev)))
+			__netif_rx_schedule(dev);
+	}
+
+	spin_unlock(&q0->lock);
+	return IRQ_HANDLED;
+}
+
+/**
+ *	t3_intr_handler - select the top-level interrupt handler
+ *	@adap: the adapter
+ *	@polling: whether using NAPI to service response queues
+ *
+ *	Selects the top-level interrupt handler based on the type of interrupts
+ *	(MSI-X, MSI, or legacy) and whether NAPI will be used to service the
+ *	response queues.
+ */
+intr_handler_t t3_intr_handler(struct adapter *adap, int polling)
+{
+	if (adap->flags & USING_MSIX)
+		return polling ? t3_sge_intr_msix_napi : t3_sge_intr_msix;
+	if (adap->flags & USING_MSI)
+		return polling ? t3_intr_msi_napi : t3_intr_msi;
+	if (adap->params.rev > 0)
+		return polling ? t3b_intr_napi : t3b_intr;
+	return t3_intr;
+}
+
+/**
+ *	t3_sge_err_intr_handler - SGE async event interrupt handler
+ *	@adapter: the adapter
+ *
+ *	Interrupt handler for SGE asynchronous (non-data) events.
+ */
+void t3_sge_err_intr_handler(struct adapter *adapter)
+{
+	unsigned int v, status = t3_read_reg(adapter, A_SG_INT_CAUSE);
+
+	if (status & F_RSPQCREDITOVERFOW)
+		CH_ALERT(adapter, "SGE response queue credit overflow\n");
+
+	if (status & F_RSPQDISABLED) {
+		v = t3_read_reg(adapter, A_SG_RSPQ_FL_STATUS);
+
+		CH_ALERT(adapter,
+			 "packet delivered to disabled response queue "
+			 "(0x%x)\n", (v >> S_RSPQ0DISABLED) & 0xff);
+	}
+
+	t3_write_reg(adapter, A_SG_INT_CAUSE, status);
+	if (status & (F_RSPQCREDITOVERFOW | F_RSPQDISABLED))
+		t3_fatal_err(adapter);
+}
+
+/**
+ *	sge_timer_cb - perform periodic maintenance of an SGE qset
+ *	@data: the SGE queue set to maintain
+ *
+ *	Runs periodically from a timer to perform maintenance of an SGE queue
+ *	set.  It performs two tasks:
+ *
+ *	a) Cleans up any completed Tx descriptors that may still be pending.
+ *	Normal descriptor cleanup happens when new packets are added to a Tx
+ *	queue so this timer is relatively infrequent and does any cleanup only
+ *	if the Tx queue has not seen any new packets in a while.  We make a
+ *	best effort attempt to reclaim descriptors, in that we don't wait
+ *	around if we cannot get a queue's lock (which most likely is because
+ *	someone else is queueing new packets and so will also handle the clean
+ *	up).  Since control queues use immediate data exclusively we don't
+ *	bother cleaning them up here.
+ *
+ *	b) Replenishes Rx queues that have run out due to memory shortage.
+ *	Normally new Rx buffers are added when existing ones are consumed but
+ *	when out of memory a queue can become empty.  We try to add only a few
+ *	buffers here, the queue will be replenished fully as these new buffers
+ *	are used up if memory shortage has subsided.
+ */
+static void sge_timer_cb(unsigned long data)
+{
+	spinlock_t *lock;
+	struct sge_qset *qs = (struct sge_qset *)data;
+	struct adapter *adap = qs->netdev->priv;
+
+	if (spin_trylock(&qs->txq[TXQ_ETH].lock)) {
+		reclaim_completed_tx(adap, &qs->txq[TXQ_ETH]);
+		spin_unlock(&qs->txq[TXQ_ETH].lock);
+	}
+	if (spin_trylock(&qs->txq[TXQ_OFLD].lock)) {
+		reclaim_completed_tx(adap, &qs->txq[TXQ_OFLD]);
+		spin_unlock(&qs->txq[TXQ_OFLD].lock);
+	}
+	lock = (adap->flags & USING_MSIX) ? &qs->rspq.lock :
+	    &adap->sge.qs[0].rspq.lock;
+	if (spin_trylock_irq(lock)) {
+		if (!napi_is_scheduled(qs->netdev)) {
+			if (qs->fl[0].credits < qs->fl[0].size)
+				__refill_fl(adap, &qs->fl[0]);
+			if (qs->fl[1].credits < qs->fl[1].size)
+				__refill_fl(adap, &qs->fl[1]);
+		}
+		spin_unlock_irq(lock);
+	}
+	mod_timer(&qs->tx_reclaim_timer, jiffies + TX_RECLAIM_PERIOD);
+}
+
+/**
+ *	t3_update_qset_coalesce - update coalescing settings for a queue set
+ *	@qs: the SGE queue set
+ *	@p: new queue set parameters
+ *
+ *	Update the coalescing settings for an SGE queue set.  Nothing is done
+ *	if the queue set is not initialized yet.
+ */
+void t3_update_qset_coalesce(struct sge_qset *qs, const struct qset_params *p)
+{
+	if (!qs->netdev)
+		return;
+
+	qs->rspq.holdoff_tmr = max(p->coalesce_usecs * 10, 1U);/* can't be 0 */
+	qs->rspq.polling = p->polling;
+	qs->netdev->poll = p->polling ? napi_rx_handler : ofld_poll;
+}
+
+/**
+ *	t3_sge_alloc_qset - initialize an SGE queue set
+ *	@adapter: the adapter
+ *	@id: the queue set id
+ *	@nports: how many Ethernet ports will be using this queue set
+ *	@irq_vec_idx: the IRQ vector index for response queue interrupts
+ *	@p: configuration parameters for this queue set
+ *	@ntxq: number of Tx queues for the queue set
+ *	@netdev: net device associated with this queue set
+ *
+ *	Allocate resources and initialize an SGE queue set.  A queue set
+ *	comprises a response queue, two Rx free-buffer queues, and up to 3
+ *	Tx queues.  The Tx queues are assigned roles in the order Ethernet
+ *	queue, offload queue, and control queue.
+ */
+int t3_sge_alloc_qset(struct adapter *adapter, unsigned int id, int nports,
+		      int irq_vec_idx, const struct qset_params *p,
+		      int ntxq, struct net_device *netdev)
+{
+	int i, ret = -ENOMEM;
+	struct sge_qset *q = &adapter->sge.qs[id];
+
+	init_qset_cntxt(q, id);
+	init_timer(&q->tx_reclaim_timer);
+	q->tx_reclaim_timer.data = (unsigned long)q;
+	q->tx_reclaim_timer.function = sge_timer_cb;
+
+	q->fl[0].desc = alloc_ring(adapter->pdev, p->fl_size,
+				   sizeof(struct rx_desc),
+				   sizeof(struct rx_sw_desc),
+				   &q->fl[0].phys_addr, &q->fl[0].sdesc);
+	if (!q->fl[0].desc)
+		goto err;
+
+	q->fl[1].desc = alloc_ring(adapter->pdev, p->jumbo_size,
+				   sizeof(struct rx_desc),
+				   sizeof(struct rx_sw_desc),
+				   &q->fl[1].phys_addr, &q->fl[1].sdesc);
+	if (!q->fl[1].desc)
+		goto err;
+
+	q->rspq.desc = alloc_ring(adapter->pdev, p->rspq_size,
+				  sizeof(struct rsp_desc), 0,
+				  &q->rspq.phys_addr, NULL);
+	if (!q->rspq.desc)
+		goto err;
+
+	for (i = 0; i < ntxq; ++i) {
+		/*
+		 * The control queue always uses immediate data so does not
+		 * need to keep track of any sk_buffs.
+		 */
+		size_t sz = i == TXQ_CTRL ? 0 : sizeof(struct tx_sw_desc);
+
+		q->txq[i].desc = alloc_ring(adapter->pdev, p->txq_size[i],
+					    sizeof(struct tx_desc), sz,
+					    &q->txq[i].phys_addr,
+					    &q->txq[i].sdesc);
+		if (!q->txq[i].desc)
+			goto err;
+
+		q->txq[i].gen = 1;
+		q->txq[i].size = p->txq_size[i];
+		spin_lock_init(&q->txq[i].lock);
+		skb_queue_head_init(&q->txq[i].sendq);
+	}
+
+	tasklet_init(&q->txq[TXQ_OFLD].qresume_tsk, restart_offloadq,
+		     (unsigned long)q);
+	tasklet_init(&q->txq[TXQ_CTRL].qresume_tsk, restart_ctrlq,
+		     (unsigned long)q);
+
+	q->fl[0].gen = q->fl[1].gen = 1;
+	q->fl[0].size = p->fl_size;
+	q->fl[1].size = p->jumbo_size;
+
+	q->rspq.gen = 1;
+	q->rspq.size = p->rspq_size;
+	spin_lock_init(&q->rspq.lock);
+
+	q->txq[TXQ_ETH].stop_thres = nports *
+	    flits_to_desc(sgl_len(MAX_SKB_FRAGS + 1) + 3);
+
+	if (ntxq == 1) {
+		q->fl[0].buf_size = SGE_RX_SM_BUF_SIZE + 2 +
+		    sizeof(struct cpl_rx_pkt);
+		q->fl[1].buf_size = MAX_FRAME_SIZE + 2 +
+		    sizeof(struct cpl_rx_pkt);
+	} else {
+		q->fl[0].buf_size = SGE_RX_SM_BUF_SIZE +
+		    sizeof(struct cpl_rx_data);
+		q->fl[1].buf_size = (16 * 1024) -
+		    SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+	}
+
+	spin_lock(&adapter->sge.reg_lock);
+
+	/* FL threshold comparison uses < */
+	ret = t3_sge_init_rspcntxt(adapter, q->rspq.cntxt_id, irq_vec_idx,
+				   q->rspq.phys_addr, q->rspq.size,
+				   q->fl[0].buf_size, 1, 0);
+	if (ret)
+		goto err_unlock;
+
+	for (i = 0; i < SGE_RXQ_PER_SET; ++i) {
+		ret = t3_sge_init_flcntxt(adapter, q->fl[i].cntxt_id, 0,
+					  q->fl[i].phys_addr, q->fl[i].size,
+					  q->fl[i].buf_size, p->cong_thres, 1,
+					  0);
+		if (ret)
+			goto err_unlock;
+	}
+
+	ret = t3_sge_init_ecntxt(adapter, q->txq[TXQ_ETH].cntxt_id, USE_GTS,
+				 SGE_CNTXT_ETH, id, q->txq[TXQ_ETH].phys_addr,
+				 q->txq[TXQ_ETH].size, q->txq[TXQ_ETH].token,
+				 1, 0);
+	if (ret)
+		goto err_unlock;
+
+	if (ntxq > 1) {
+		ret = t3_sge_init_ecntxt(adapter, q->txq[TXQ_OFLD].cntxt_id,
+					 USE_GTS, SGE_CNTXT_OFLD, id,
+					 q->txq[TXQ_OFLD].phys_addr,
+					 q->txq[TXQ_OFLD].size, 0, 1, 0);
+		if (ret)
+			goto err_unlock;
+	}
+
+	if (ntxq > 2) {
+		ret = t3_sge_init_ecntxt(adapter, q->txq[TXQ_CTRL].cntxt_id, 0,
+					 SGE_CNTXT_CTRL, id,
+					 q->txq[TXQ_CTRL].phys_addr,
+					 q->txq[TXQ_CTRL].size,
+					 q->txq[TXQ_CTRL].token, 1, 0);
+		if (ret)
+			goto err_unlock;
+	}
+
+	spin_unlock(&adapter->sge.reg_lock);
+	q->netdev = netdev;
+	t3_update_qset_coalesce(q, p);
+
+	/*
+	 * We use atalk_ptr as a backpointer to a qset.  In case a device is
+	 * associated with multiple queue sets only the first one sets
+	 * atalk_ptr.
+	 */
+	if (netdev->atalk_ptr == NULL)
+		netdev->atalk_ptr = q;
+
+	refill_fl(adapter, &q->fl[0], q->fl[0].size, GFP_KERNEL);
+	refill_fl(adapter, &q->fl[1], q->fl[1].size, GFP_KERNEL);
+	refill_rspq(adapter, &q->rspq, q->rspq.size - 1);
+
+	t3_write_reg(adapter, A_SG_GTS, V_RSPQ(q->rspq.cntxt_id) |
+		     V_NEWTIMER(q->rspq.holdoff_tmr));
+
+	mod_timer(&q->tx_reclaim_timer, jiffies + TX_RECLAIM_PERIOD);
+	return 0;
+
+      err_unlock:
+	spin_unlock(&adapter->sge.reg_lock);
+      err:
+	t3_free_qset(adapter, q);
+	return ret;
+}
+
+/**
+ *	t3_free_sge_resources - free SGE resources
+ *	@adap: the adapter
+ *
+ *	Frees resources used by the SGE queue sets.
+ */
+void t3_free_sge_resources(struct adapter *adap)
+{
+	int i;
+
+	for (i = 0; i < SGE_QSETS; ++i)
+		t3_free_qset(adap, &adap->sge.qs[i]);
+}
+
+/**
+ *	t3_sge_start - enable SGE
+ *	@adap: the adapter
+ *
+ *	Enables the SGE for DMAs.  This is the last step in starting packet
+ *	transfers.
+ */
+void t3_sge_start(struct adapter *adap)
+{
+	t3_set_reg_field(adap, A_SG_CONTROL, F_GLOBALENABLE, F_GLOBALENABLE);
+}
+
+/**
+ *	t3_sge_stop - disable SGE operation
+ *	@adap: the adapter
+ *
+ *	Disables the DMA engine.  This can be called in emeregencies (e.g.,
+ *	from error interrupts) or from normal process context.  In the latter
+ *	case it also disables any pending queue restart tasklets.  Note that
+ *	if it is called in interrupt context it cannot disable the restart
+ *	tasklets as it cannot wait, however the tasklets will have no effect
+ *	since the doorbells are disabled and the driver will call this again
+ *	later from process context, at which time the tasklets will be stopped
+ *	if they are still running.
+ */
+void t3_sge_stop(struct adapter *adap)
+{
+	t3_set_reg_field(adap, A_SG_CONTROL, F_GLOBALENABLE, 0);
+	if (!in_interrupt()) {
+		int i;
+
+		for (i = 0; i < SGE_QSETS; ++i) {
+			struct sge_qset *qs = &adap->sge.qs[i];
+
+			tasklet_kill(&qs->txq[TXQ_OFLD].qresume_tsk);
+			tasklet_kill(&qs->txq[TXQ_CTRL].qresume_tsk);
+		}
+	}
+}
+
+/**
+ *	t3_sge_init - initialize SGE
+ *	@adap: the adapter
+ *	@p: the SGE parameters
+ *
+ *	Performs SGE initialization needed every time after a chip reset.
+ *	We do not initialize any of the queue sets here, instead the driver
+ *	top-level must request those individually.  We also do not enable DMA
+ *	here, that should be done after the queues have been set up.
+ */
+void t3_sge_init(struct adapter *adap, struct sge_params *p)
+{
+	unsigned int ctrl, ups = ffs(pci_resource_len(adap->pdev, 2) >> 12);
+
+	ctrl = F_DROPPKT | V_PKTSHIFT(2) | F_FLMODE | F_AVOIDCQOVFL |
+	    F_CQCRDTCTRL |
+	    V_HOSTPAGESIZE(PAGE_SHIFT - 11) | F_BIGENDIANINGRESS |
+	    V_USERSPACESIZE(ups ? ups - 1 : 0) | F_ISCSICOALESCING;
+#if SGE_NUM_GENBITS == 1
+	ctrl |= F_EGRGENCTRL;
+#endif
+	if (adap->params.rev > 0) {
+		if (!(adap->flags & (USING_MSIX | USING_MSI)))
+			ctrl |= F_ONEINTMULTQ | F_OPTONEINTMULTQ;
+		ctrl |= F_CQCRDTCTRL | F_AVOIDCQOVFL;
+	}
+	t3_write_reg(adap, A_SG_CONTROL, ctrl);
+	t3_write_reg(adap, A_SG_EGR_RCQ_DRB_THRSH, V_HIRCQDRBTHRSH(512) |
+		     V_LORCQDRBTHRSH(512));
+	t3_write_reg(adap, A_SG_TIMER_TICK, core_ticks_per_usec(adap) / 10);
+	t3_write_reg(adap, A_SG_CMDQ_CREDIT_TH, V_THRESHOLD(32) |
+		     V_TIMEOUT(100 * core_ticks_per_usec(adap)));
+	t3_write_reg(adap, A_SG_HI_DRB_HI_THRSH, 1000);
+	t3_write_reg(adap, A_SG_HI_DRB_LO_THRSH, 256);
+	t3_write_reg(adap, A_SG_LO_DRB_HI_THRSH, 1000);
+	t3_write_reg(adap, A_SG_LO_DRB_LO_THRSH, 256);
+	t3_write_reg(adap, A_SG_OCO_BASE, V_BASE1(0xfff));
+	t3_write_reg(adap, A_SG_DRB_PRI_THRESH, 63 * 1024);
+}
+
+/**
+ *	t3_sge_prep - one-time SGE initialization
+ *	@adap: the associated adapter
+ *	@p: SGE parameters
+ *
+ *	Performs one-time initialization of SGE SW state.  Includes determining
+ *	defaults for the assorted SGE parameters, which admins can change until
+ *	they are used to initialize the SGE.
+ */
+void __devinit t3_sge_prep(struct adapter *adap, struct sge_params *p)
+{
+	int i;
+
+	p->max_pkt_size = (16 * 1024) - sizeof(struct cpl_rx_data) -
+	    SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+
+	for (i = 0; i < SGE_QSETS; ++i) {
+		struct qset_params *q = p->qset + i;
+
+		q->polling = adap->params.rev > 0;
+		q->coalesce_usecs = 5;
+		q->rspq_size = 1024;
+		q->fl_size = 4096;
+		q->jumbo_size = 512;
+		q->txq_size[TXQ_ETH] = 1024;
+		q->txq_size[TXQ_OFLD] = 1024;
+		q->txq_size[TXQ_CTRL] = 256;
+		q->cong_thres = 0;
+	}
+
+	spin_lock_init(&adap->sge.reg_lock);
+}
+
+/**
+ *	t3_get_desc - dump an SGE descriptor for debugging purposes
+ *	@qs: the queue set
+ *	@qnum: identifies the specific queue (0..2: Tx, 3:response, 4..5: Rx)
+ *	@idx: the descriptor index in the queue
+ *	@data: where to dump the descriptor contents
+ *
+ *	Dumps the contents of a HW descriptor of an SGE queue.  Returns the
+ *	size of the descriptor.
+ */
+int t3_get_desc(const struct sge_qset *qs, unsigned int qnum, unsigned int idx,
+		unsigned char *data)
+{
+	if (qnum >= 6)
+		return -EINVAL;
+
+	if (qnum < 3) {
+		if (!qs->txq[qnum].desc || idx >= qs->txq[qnum].size)
+			return -EINVAL;
+		memcpy(data, &qs->txq[qnum].desc[idx], sizeof(struct tx_desc));
+		return sizeof(struct tx_desc);
+	}
+
+	if (qnum == 3) {
+		if (!qs->rspq.desc || idx >= qs->rspq.size)
+			return -EINVAL;
+		memcpy(data, &qs->rspq.desc[idx], sizeof(struct rsp_desc));
+		return sizeof(struct rsp_desc);
+	}
+
+	qnum -= 4;
+	if (!qs->fl[qnum].desc || idx >= qs->fl[qnum].size)
+		return -EINVAL;
+	memcpy(data, &qs->fl[qnum].desc[idx], sizeof(struct rx_desc));
+	return sizeof(struct rx_desc);
+}