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  • only in /asuswrt-rt-n18u-9.0.0.4.380.2695/release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/net/mlx4/
1/*
2 * Copyright (c) 2007 Mellanox Technologies. All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses.  You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 *     Redistribution and use in source and binary forms, with or
11 *     without modification, are permitted provided that the following
12 *     conditions are met:
13 *
14 *      - Redistributions of source code must retain the above
15 *        copyright notice, this list of conditions and the following
16 *        disclaimer.
17 *
18 *      - Redistributions in binary form must reproduce the above
19 *        copyright notice, this list of conditions and the following
20 *        disclaimer in the documentation and/or other materials
21 *        provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 *
32 */
33
34#include <asm/page.h>
35#include <linux/mlx4/cq.h>
36#include <linux/slab.h>
37#include <linux/mlx4/qp.h>
38#include <linux/skbuff.h>
39#include <linux/if_vlan.h>
40#include <linux/vmalloc.h>
41
42#include "mlx4_en.h"
43
44enum {
45	MAX_INLINE = 104, /* 128 - 16 - 4 - 4 */
46};
47
48static int inline_thold __read_mostly = MAX_INLINE;
49
50module_param_named(inline_thold, inline_thold, int, 0444);
51MODULE_PARM_DESC(inline_thold, "threshold for using inline data");
52
53int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,
54			   struct mlx4_en_tx_ring *ring, u32 size,
55			   u16 stride)
56{
57	struct mlx4_en_dev *mdev = priv->mdev;
58	int tmp;
59	int err;
60
61	ring->size = size;
62	ring->size_mask = size - 1;
63	ring->stride = stride;
64
65	inline_thold = min(inline_thold, MAX_INLINE);
66
67	spin_lock_init(&ring->comp_lock);
68
69	tmp = size * sizeof(struct mlx4_en_tx_info);
70	ring->tx_info = vmalloc(tmp);
71	if (!ring->tx_info) {
72		en_err(priv, "Failed allocating tx_info ring\n");
73		return -ENOMEM;
74	}
75	en_dbg(DRV, priv, "Allocated tx_info ring at addr:%p size:%d\n",
76		 ring->tx_info, tmp);
77
78	ring->bounce_buf = kmalloc(MAX_DESC_SIZE, GFP_KERNEL);
79	if (!ring->bounce_buf) {
80		en_err(priv, "Failed allocating bounce buffer\n");
81		err = -ENOMEM;
82		goto err_tx;
83	}
84	ring->buf_size = ALIGN(size * ring->stride, MLX4_EN_PAGE_SIZE);
85
86	err = mlx4_alloc_hwq_res(mdev->dev, &ring->wqres, ring->buf_size,
87				 2 * PAGE_SIZE);
88	if (err) {
89		en_err(priv, "Failed allocating hwq resources\n");
90		goto err_bounce;
91	}
92
93	err = mlx4_en_map_buffer(&ring->wqres.buf);
94	if (err) {
95		en_err(priv, "Failed to map TX buffer\n");
96		goto err_hwq_res;
97	}
98
99	ring->buf = ring->wqres.buf.direct.buf;
100
101	en_dbg(DRV, priv, "Allocated TX ring (addr:%p) - buf:%p size:%d "
102	       "buf_size:%d dma:%llx\n", ring, ring->buf, ring->size,
103	       ring->buf_size, (unsigned long long) ring->wqres.buf.direct.map);
104
105	err = mlx4_qp_reserve_range(mdev->dev, 1, 1, &ring->qpn);
106	if (err) {
107		en_err(priv, "Failed reserving qp for tx ring.\n");
108		goto err_map;
109	}
110
111	err = mlx4_qp_alloc(mdev->dev, ring->qpn, &ring->qp);
112	if (err) {
113		en_err(priv, "Failed allocating qp %d\n", ring->qpn);
114		goto err_reserve;
115	}
116	ring->qp.event = mlx4_en_sqp_event;
117
118	return 0;
119
120err_reserve:
121	mlx4_qp_release_range(mdev->dev, ring->qpn, 1);
122err_map:
123	mlx4_en_unmap_buffer(&ring->wqres.buf);
124err_hwq_res:
125	mlx4_free_hwq_res(mdev->dev, &ring->wqres, ring->buf_size);
126err_bounce:
127	kfree(ring->bounce_buf);
128	ring->bounce_buf = NULL;
129err_tx:
130	vfree(ring->tx_info);
131	ring->tx_info = NULL;
132	return err;
133}
134
135void mlx4_en_destroy_tx_ring(struct mlx4_en_priv *priv,
136			     struct mlx4_en_tx_ring *ring)
137{
138	struct mlx4_en_dev *mdev = priv->mdev;
139	en_dbg(DRV, priv, "Destroying tx ring, qpn: %d\n", ring->qpn);
140
141	mlx4_qp_remove(mdev->dev, &ring->qp);
142	mlx4_qp_free(mdev->dev, &ring->qp);
143	mlx4_qp_release_range(mdev->dev, ring->qpn, 1);
144	mlx4_en_unmap_buffer(&ring->wqres.buf);
145	mlx4_free_hwq_res(mdev->dev, &ring->wqres, ring->buf_size);
146	kfree(ring->bounce_buf);
147	ring->bounce_buf = NULL;
148	vfree(ring->tx_info);
149	ring->tx_info = NULL;
150}
151
152int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv,
153			     struct mlx4_en_tx_ring *ring,
154			     int cq)
155{
156	struct mlx4_en_dev *mdev = priv->mdev;
157	int err;
158
159	ring->cqn = cq;
160	ring->prod = 0;
161	ring->cons = 0xffffffff;
162	ring->last_nr_txbb = 1;
163	ring->poll_cnt = 0;
164	ring->blocked = 0;
165	memset(ring->tx_info, 0, ring->size * sizeof(struct mlx4_en_tx_info));
166	memset(ring->buf, 0, ring->buf_size);
167
168	ring->qp_state = MLX4_QP_STATE_RST;
169	ring->doorbell_qpn = swab32(ring->qp.qpn << 8);
170
171	mlx4_en_fill_qp_context(priv, ring->size, ring->stride, 1, 0, ring->qpn,
172				ring->cqn, &ring->context);
173
174	err = mlx4_qp_to_ready(mdev->dev, &ring->wqres.mtt, &ring->context,
175			       &ring->qp, &ring->qp_state);
176
177	return err;
178}
179
180void mlx4_en_deactivate_tx_ring(struct mlx4_en_priv *priv,
181				struct mlx4_en_tx_ring *ring)
182{
183	struct mlx4_en_dev *mdev = priv->mdev;
184
185	mlx4_qp_modify(mdev->dev, NULL, ring->qp_state,
186		       MLX4_QP_STATE_RST, NULL, 0, 0, &ring->qp);
187}
188
189
190static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
191				struct mlx4_en_tx_ring *ring,
192				int index, u8 owner)
193{
194	struct mlx4_en_dev *mdev = priv->mdev;
195	struct mlx4_en_tx_info *tx_info = &ring->tx_info[index];
196	struct mlx4_en_tx_desc *tx_desc = ring->buf + index * TXBB_SIZE;
197	struct mlx4_wqe_data_seg *data = (void *) tx_desc + tx_info->data_offset;
198	struct sk_buff *skb = tx_info->skb;
199	struct skb_frag_struct *frag;
200	void *end = ring->buf + ring->buf_size;
201	int frags = skb_shinfo(skb)->nr_frags;
202	int i;
203	__be32 *ptr = (__be32 *)tx_desc;
204	__be32 stamp = cpu_to_be32(STAMP_VAL | (!!owner << STAMP_SHIFT));
205
206	/* Optimize the common case when there are no wraparounds */
207	if (likely((void *) tx_desc + tx_info->nr_txbb * TXBB_SIZE <= end)) {
208		if (!tx_info->inl) {
209			if (tx_info->linear) {
210				pci_unmap_single(mdev->pdev,
211					(dma_addr_t) be64_to_cpu(data->addr),
212					 be32_to_cpu(data->byte_count),
213					 PCI_DMA_TODEVICE);
214				++data;
215			}
216
217			for (i = 0; i < frags; i++) {
218				frag = &skb_shinfo(skb)->frags[i];
219				pci_unmap_page(mdev->pdev,
220					(dma_addr_t) be64_to_cpu(data[i].addr),
221					frag->size, PCI_DMA_TODEVICE);
222			}
223		}
224		/* Stamp the freed descriptor */
225		for (i = 0; i < tx_info->nr_txbb * TXBB_SIZE; i += STAMP_STRIDE) {
226			*ptr = stamp;
227			ptr += STAMP_DWORDS;
228		}
229
230	} else {
231		if (!tx_info->inl) {
232			if ((void *) data >= end) {
233				data = (struct mlx4_wqe_data_seg *)
234						(ring->buf + ((void *) data - end));
235			}
236
237			if (tx_info->linear) {
238				pci_unmap_single(mdev->pdev,
239					(dma_addr_t) be64_to_cpu(data->addr),
240					 be32_to_cpu(data->byte_count),
241					 PCI_DMA_TODEVICE);
242				++data;
243			}
244
245			for (i = 0; i < frags; i++) {
246				/* Check for wraparound before unmapping */
247				if ((void *) data >= end)
248					data = (struct mlx4_wqe_data_seg *) ring->buf;
249				frag = &skb_shinfo(skb)->frags[i];
250				pci_unmap_page(mdev->pdev,
251					(dma_addr_t) be64_to_cpu(data->addr),
252					 frag->size, PCI_DMA_TODEVICE);
253				++data;
254			}
255		}
256		/* Stamp the freed descriptor */
257		for (i = 0; i < tx_info->nr_txbb * TXBB_SIZE; i += STAMP_STRIDE) {
258			*ptr = stamp;
259			ptr += STAMP_DWORDS;
260			if ((void *) ptr >= end) {
261				ptr = ring->buf;
262				stamp ^= cpu_to_be32(0x80000000);
263			}
264		}
265
266	}
267	dev_kfree_skb_any(skb);
268	return tx_info->nr_txbb;
269}
270
271
272int mlx4_en_free_tx_buf(struct net_device *dev, struct mlx4_en_tx_ring *ring)
273{
274	struct mlx4_en_priv *priv = netdev_priv(dev);
275	int cnt = 0;
276
277	/* Skip last polled descriptor */
278	ring->cons += ring->last_nr_txbb;
279	en_dbg(DRV, priv, "Freeing Tx buf - cons:0x%x prod:0x%x\n",
280		 ring->cons, ring->prod);
281
282	if ((u32) (ring->prod - ring->cons) > ring->size) {
283		if (netif_msg_tx_err(priv))
284			en_warn(priv, "Tx consumer passed producer!\n");
285		return 0;
286	}
287
288	while (ring->cons != ring->prod) {
289		ring->last_nr_txbb = mlx4_en_free_tx_desc(priv, ring,
290						ring->cons & ring->size_mask,
291						!!(ring->cons & ring->size));
292		ring->cons += ring->last_nr_txbb;
293		cnt++;
294	}
295
296	if (cnt)
297		en_dbg(DRV, priv, "Freed %d uncompleted tx descriptors\n", cnt);
298
299	return cnt;
300}
301
302
303static void mlx4_en_process_tx_cq(struct net_device *dev, struct mlx4_en_cq *cq)
304{
305	struct mlx4_en_priv *priv = netdev_priv(dev);
306	struct mlx4_cq *mcq = &cq->mcq;
307	struct mlx4_en_tx_ring *ring = &priv->tx_ring[cq->ring];
308	struct mlx4_cqe *cqe = cq->buf;
309	u16 index;
310	u16 new_index;
311	u32 txbbs_skipped = 0;
312	u32 cq_last_sav;
313
314	/* index always points to the first TXBB of the last polled descriptor */
315	index = ring->cons & ring->size_mask;
316	new_index = be16_to_cpu(cqe->wqe_index) & ring->size_mask;
317	if (index == new_index)
318		return;
319
320	if (!priv->port_up)
321		return;
322
323	/*
324	 * We use a two-stage loop:
325	 * - the first samples the HW-updated CQE
326	 * - the second frees TXBBs until the last sample
327	 * This lets us amortize CQE cache misses, while still polling the CQ
328	 * until is quiescent.
329	 */
330	cq_last_sav = mcq->cons_index;
331	do {
332		do {
333			/* Skip over last polled CQE */
334			index = (index + ring->last_nr_txbb) & ring->size_mask;
335			txbbs_skipped += ring->last_nr_txbb;
336
337			/* Poll next CQE */
338			ring->last_nr_txbb = mlx4_en_free_tx_desc(
339						priv, ring, index,
340						!!((ring->cons + txbbs_skipped) &
341						   ring->size));
342			++mcq->cons_index;
343
344		} while (index != new_index);
345
346		new_index = be16_to_cpu(cqe->wqe_index) & ring->size_mask;
347	} while (index != new_index);
348	AVG_PERF_COUNTER(priv->pstats.tx_coal_avg,
349			 (u32) (mcq->cons_index - cq_last_sav));
350
351	/*
352	 * To prevent CQ overflow we first update CQ consumer and only then
353	 * the ring consumer.
354	 */
355	mlx4_cq_set_ci(mcq);
356	wmb();
357	ring->cons += txbbs_skipped;
358
359	/* Wakeup Tx queue if this ring stopped it */
360	if (unlikely(ring->blocked)) {
361		if ((u32) (ring->prod - ring->cons) <=
362		     ring->size - HEADROOM - MAX_DESC_TXBBS) {
363			ring->blocked = 0;
364			netif_tx_wake_queue(netdev_get_tx_queue(dev, cq->ring));
365			priv->port_stats.wake_queue++;
366		}
367	}
368}
369
370void mlx4_en_tx_irq(struct mlx4_cq *mcq)
371{
372	struct mlx4_en_cq *cq = container_of(mcq, struct mlx4_en_cq, mcq);
373	struct mlx4_en_priv *priv = netdev_priv(cq->dev);
374	struct mlx4_en_tx_ring *ring = &priv->tx_ring[cq->ring];
375
376	if (!spin_trylock(&ring->comp_lock))
377		return;
378	mlx4_en_process_tx_cq(cq->dev, cq);
379	mod_timer(&cq->timer, jiffies + 1);
380	spin_unlock(&ring->comp_lock);
381}
382
383
384void mlx4_en_poll_tx_cq(unsigned long data)
385{
386	struct mlx4_en_cq *cq = (struct mlx4_en_cq *) data;
387	struct mlx4_en_priv *priv = netdev_priv(cq->dev);
388	struct mlx4_en_tx_ring *ring = &priv->tx_ring[cq->ring];
389	u32 inflight;
390
391	INC_PERF_COUNTER(priv->pstats.tx_poll);
392
393	if (!spin_trylock_irq(&ring->comp_lock)) {
394		mod_timer(&cq->timer, jiffies + MLX4_EN_TX_POLL_TIMEOUT);
395		return;
396	}
397	mlx4_en_process_tx_cq(cq->dev, cq);
398	inflight = (u32) (ring->prod - ring->cons - ring->last_nr_txbb);
399
400	/* If there are still packets in flight and the timer has not already
401	 * been scheduled by the Tx routine then schedule it here to guarantee
402	 * completion processing of these packets */
403	if (inflight && priv->port_up)
404		mod_timer(&cq->timer, jiffies + MLX4_EN_TX_POLL_TIMEOUT);
405
406	spin_unlock_irq(&ring->comp_lock);
407}
408
409static struct mlx4_en_tx_desc *mlx4_en_bounce_to_desc(struct mlx4_en_priv *priv,
410						      struct mlx4_en_tx_ring *ring,
411						      u32 index,
412						      unsigned int desc_size)
413{
414	u32 copy = (ring->size - index) * TXBB_SIZE;
415	int i;
416
417	for (i = desc_size - copy - 4; i >= 0; i -= 4) {
418		if ((i & (TXBB_SIZE - 1)) == 0)
419			wmb();
420
421		*((u32 *) (ring->buf + i)) =
422			*((u32 *) (ring->bounce_buf + copy + i));
423	}
424
425	for (i = copy - 4; i >= 4 ; i -= 4) {
426		if ((i & (TXBB_SIZE - 1)) == 0)
427			wmb();
428
429		*((u32 *) (ring->buf + index * TXBB_SIZE + i)) =
430			*((u32 *) (ring->bounce_buf + i));
431	}
432
433	/* Return real descriptor location */
434	return ring->buf + index * TXBB_SIZE;
435}
436
437static inline void mlx4_en_xmit_poll(struct mlx4_en_priv *priv, int tx_ind)
438{
439	struct mlx4_en_cq *cq = &priv->tx_cq[tx_ind];
440	struct mlx4_en_tx_ring *ring = &priv->tx_ring[tx_ind];
441	unsigned long flags;
442
443	/* If we don't have a pending timer, set one up to catch our recent
444	   post in case the interface becomes idle */
445	if (!timer_pending(&cq->timer))
446		mod_timer(&cq->timer, jiffies + MLX4_EN_TX_POLL_TIMEOUT);
447
448	/* Poll the CQ every mlx4_en_TX_MODER_POLL packets */
449	if ((++ring->poll_cnt & (MLX4_EN_TX_POLL_MODER - 1)) == 0)
450		if (spin_trylock_irqsave(&ring->comp_lock, flags)) {
451			mlx4_en_process_tx_cq(priv->dev, cq);
452			spin_unlock_irqrestore(&ring->comp_lock, flags);
453		}
454}
455
456static void *get_frag_ptr(struct sk_buff *skb)
457{
458	struct skb_frag_struct *frag =  &skb_shinfo(skb)->frags[0];
459	struct page *page = frag->page;
460	void *ptr;
461
462	ptr = page_address(page);
463	if (unlikely(!ptr))
464		return NULL;
465
466	return ptr + frag->page_offset;
467}
468
469static int is_inline(struct sk_buff *skb, void **pfrag)
470{
471	void *ptr;
472
473	if (inline_thold && !skb_is_gso(skb) && skb->len <= inline_thold) {
474		if (skb_shinfo(skb)->nr_frags == 1) {
475			ptr = get_frag_ptr(skb);
476			if (unlikely(!ptr))
477				return 0;
478
479			if (pfrag)
480				*pfrag = ptr;
481
482			return 1;
483		} else if (unlikely(skb_shinfo(skb)->nr_frags))
484			return 0;
485		else
486			return 1;
487	}
488
489	return 0;
490}
491
492static int inline_size(struct sk_buff *skb)
493{
494	if (skb->len + CTRL_SIZE + sizeof(struct mlx4_wqe_inline_seg)
495	    <= MLX4_INLINE_ALIGN)
496		return ALIGN(skb->len + CTRL_SIZE +
497			     sizeof(struct mlx4_wqe_inline_seg), 16);
498	else
499		return ALIGN(skb->len + CTRL_SIZE + 2 *
500			     sizeof(struct mlx4_wqe_inline_seg), 16);
501}
502
503static int get_real_size(struct sk_buff *skb, struct net_device *dev,
504			 int *lso_header_size)
505{
506	struct mlx4_en_priv *priv = netdev_priv(dev);
507	int real_size;
508
509	if (skb_is_gso(skb)) {
510		*lso_header_size = skb_transport_offset(skb) + tcp_hdrlen(skb);
511		real_size = CTRL_SIZE + skb_shinfo(skb)->nr_frags * DS_SIZE +
512			ALIGN(*lso_header_size + 4, DS_SIZE);
513		if (unlikely(*lso_header_size != skb_headlen(skb))) {
514			/* We add a segment for the skb linear buffer only if
515			 * it contains data */
516			if (*lso_header_size < skb_headlen(skb))
517				real_size += DS_SIZE;
518			else {
519				if (netif_msg_tx_err(priv))
520					en_warn(priv, "Non-linear headers\n");
521				return 0;
522			}
523		}
524	} else {
525		*lso_header_size = 0;
526		if (!is_inline(skb, NULL))
527			real_size = CTRL_SIZE + (skb_shinfo(skb)->nr_frags + 1) * DS_SIZE;
528		else
529			real_size = inline_size(skb);
530	}
531
532	return real_size;
533}
534
535static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc, struct sk_buff *skb,
536			     int real_size, u16 *vlan_tag, int tx_ind, void *fragptr)
537{
538	struct mlx4_wqe_inline_seg *inl = &tx_desc->inl;
539	int spc = MLX4_INLINE_ALIGN - CTRL_SIZE - sizeof *inl;
540
541	if (skb->len <= spc) {
542		inl->byte_count = cpu_to_be32(1 << 31 | skb->len);
543		skb_copy_from_linear_data(skb, inl + 1, skb_headlen(skb));
544		if (skb_shinfo(skb)->nr_frags)
545			memcpy(((void *)(inl + 1)) + skb_headlen(skb), fragptr,
546			       skb_shinfo(skb)->frags[0].size);
547
548	} else {
549		inl->byte_count = cpu_to_be32(1 << 31 | spc);
550		if (skb_headlen(skb) <= spc) {
551			skb_copy_from_linear_data(skb, inl + 1, skb_headlen(skb));
552			if (skb_headlen(skb) < spc) {
553				memcpy(((void *)(inl + 1)) + skb_headlen(skb),
554					fragptr, spc - skb_headlen(skb));
555				fragptr +=  spc - skb_headlen(skb);
556			}
557			inl = (void *) (inl + 1) + spc;
558			memcpy(((void *)(inl + 1)), fragptr, skb->len - spc);
559		} else {
560			skb_copy_from_linear_data(skb, inl + 1, spc);
561			inl = (void *) (inl + 1) + spc;
562			skb_copy_from_linear_data_offset(skb, spc, inl + 1,
563					skb_headlen(skb) - spc);
564			if (skb_shinfo(skb)->nr_frags)
565				memcpy(((void *)(inl + 1)) + skb_headlen(skb) - spc,
566					fragptr, skb_shinfo(skb)->frags[0].size);
567		}
568
569		wmb();
570		inl->byte_count = cpu_to_be32(1 << 31 | (skb->len - spc));
571	}
572	tx_desc->ctrl.vlan_tag = cpu_to_be16(*vlan_tag);
573	tx_desc->ctrl.ins_vlan = MLX4_WQE_CTRL_INS_VLAN * !!(*vlan_tag);
574	tx_desc->ctrl.fence_size = (real_size / 16) & 0x3f;
575}
576
577u16 mlx4_en_select_queue(struct net_device *dev, struct sk_buff *skb)
578{
579	struct mlx4_en_priv *priv = netdev_priv(dev);
580	u16 vlan_tag = 0;
581
582	/* If we support per priority flow control and the packet contains
583	 * a vlan tag, send the packet to the TX ring assigned to that priority
584	 */
585	if (priv->prof->rx_ppp && priv->vlgrp && vlan_tx_tag_present(skb)) {
586		vlan_tag = vlan_tx_tag_get(skb);
587		return MLX4_EN_NUM_TX_RINGS + (vlan_tag >> 13);
588	}
589
590	return skb_tx_hash(dev, skb);
591}
592
593netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
594{
595	struct mlx4_en_priv *priv = netdev_priv(dev);
596	struct mlx4_en_dev *mdev = priv->mdev;
597	struct mlx4_en_tx_ring *ring;
598	struct mlx4_en_cq *cq;
599	struct mlx4_en_tx_desc *tx_desc;
600	struct mlx4_wqe_data_seg *data;
601	struct skb_frag_struct *frag;
602	struct mlx4_en_tx_info *tx_info;
603	int tx_ind = 0;
604	int nr_txbb;
605	int desc_size;
606	int real_size;
607	dma_addr_t dma;
608	u32 index;
609	__be32 op_own;
610	u16 vlan_tag = 0;
611	int i;
612	int lso_header_size;
613	void *fragptr;
614
615	real_size = get_real_size(skb, dev, &lso_header_size);
616	if (unlikely(!real_size))
617		goto tx_drop;
618
619	/* Allign descriptor to TXBB size */
620	desc_size = ALIGN(real_size, TXBB_SIZE);
621	nr_txbb = desc_size / TXBB_SIZE;
622	if (unlikely(nr_txbb > MAX_DESC_TXBBS)) {
623		if (netif_msg_tx_err(priv))
624			en_warn(priv, "Oversized header or SG list\n");
625		goto tx_drop;
626	}
627
628	tx_ind = skb->queue_mapping;
629	ring = &priv->tx_ring[tx_ind];
630	if (priv->vlgrp && vlan_tx_tag_present(skb))
631		vlan_tag = vlan_tx_tag_get(skb);
632
633	/* Check available TXBBs And 2K spare for prefetch */
634	if (unlikely(((int)(ring->prod - ring->cons)) >
635		     ring->size - HEADROOM - MAX_DESC_TXBBS)) {
636		/* every full Tx ring stops queue */
637		netif_tx_stop_queue(netdev_get_tx_queue(dev, tx_ind));
638		ring->blocked = 1;
639		priv->port_stats.queue_stopped++;
640
641		/* Use interrupts to find out when queue opened */
642		cq = &priv->tx_cq[tx_ind];
643		mlx4_en_arm_cq(priv, cq);
644		return NETDEV_TX_BUSY;
645	}
646
647	/* Track current inflight packets for performance analysis */
648	AVG_PERF_COUNTER(priv->pstats.inflight_avg,
649			 (u32) (ring->prod - ring->cons - 1));
650
651	/* Packet is good - grab an index and transmit it */
652	index = ring->prod & ring->size_mask;
653
654	/* See if we have enough space for whole descriptor TXBB for setting
655	 * SW ownership on next descriptor; if not, use a bounce buffer. */
656	if (likely(index + nr_txbb <= ring->size))
657		tx_desc = ring->buf + index * TXBB_SIZE;
658	else
659		tx_desc = (struct mlx4_en_tx_desc *) ring->bounce_buf;
660
661	/* Save skb in tx_info ring */
662	tx_info = &ring->tx_info[index];
663	tx_info->skb = skb;
664	tx_info->nr_txbb = nr_txbb;
665
666	/* Prepare ctrl segement apart opcode+ownership, which depends on
667	 * whether LSO is used */
668	tx_desc->ctrl.vlan_tag = cpu_to_be16(vlan_tag);
669	tx_desc->ctrl.ins_vlan = MLX4_WQE_CTRL_INS_VLAN * !!vlan_tag;
670	tx_desc->ctrl.fence_size = (real_size / 16) & 0x3f;
671	tx_desc->ctrl.srcrb_flags = cpu_to_be32(MLX4_WQE_CTRL_CQ_UPDATE |
672						MLX4_WQE_CTRL_SOLICITED);
673	if (likely(skb->ip_summed == CHECKSUM_PARTIAL)) {
674		tx_desc->ctrl.srcrb_flags |= cpu_to_be32(MLX4_WQE_CTRL_IP_CSUM |
675							 MLX4_WQE_CTRL_TCP_UDP_CSUM);
676		priv->port_stats.tx_chksum_offload++;
677	}
678
679	/* Handle LSO (TSO) packets */
680	if (lso_header_size) {
681		/* Mark opcode as LSO */
682		op_own = cpu_to_be32(MLX4_OPCODE_LSO | (1 << 6)) |
683			((ring->prod & ring->size) ?
684				cpu_to_be32(MLX4_EN_BIT_DESC_OWN) : 0);
685
686		/* Fill in the LSO prefix */
687		tx_desc->lso.mss_hdr_size = cpu_to_be32(
688			skb_shinfo(skb)->gso_size << 16 | lso_header_size);
689
690		/* Copy headers;
691		 * note that we already verified that it is linear */
692		memcpy(tx_desc->lso.header, skb->data, lso_header_size);
693		data = ((void *) &tx_desc->lso +
694			ALIGN(lso_header_size + 4, DS_SIZE));
695
696		priv->port_stats.tso_packets++;
697		i = ((skb->len - lso_header_size) / skb_shinfo(skb)->gso_size) +
698			!!((skb->len - lso_header_size) % skb_shinfo(skb)->gso_size);
699		ring->bytes += skb->len + (i - 1) * lso_header_size;
700		ring->packets += i;
701	} else {
702		/* Normal (Non LSO) packet */
703		op_own = cpu_to_be32(MLX4_OPCODE_SEND) |
704			((ring->prod & ring->size) ?
705			 cpu_to_be32(MLX4_EN_BIT_DESC_OWN) : 0);
706		data = &tx_desc->data;
707		ring->bytes += max(skb->len, (unsigned int) ETH_ZLEN);
708		ring->packets++;
709
710	}
711	AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, skb->len);
712
713
714	/* valid only for none inline segments */
715	tx_info->data_offset = (void *) data - (void *) tx_desc;
716
717	tx_info->linear = (lso_header_size < skb_headlen(skb) && !is_inline(skb, NULL)) ? 1 : 0;
718	data += skb_shinfo(skb)->nr_frags + tx_info->linear - 1;
719
720	if (!is_inline(skb, &fragptr)) {
721		/* Map fragments */
722		for (i = skb_shinfo(skb)->nr_frags - 1; i >= 0; i--) {
723			frag = &skb_shinfo(skb)->frags[i];
724			dma = pci_map_page(mdev->dev->pdev, frag->page, frag->page_offset,
725					   frag->size, PCI_DMA_TODEVICE);
726			data->addr = cpu_to_be64(dma);
727			data->lkey = cpu_to_be32(mdev->mr.key);
728			wmb();
729			data->byte_count = cpu_to_be32(frag->size);
730			--data;
731		}
732
733		/* Map linear part */
734		if (tx_info->linear) {
735			dma = pci_map_single(mdev->dev->pdev, skb->data + lso_header_size,
736					     skb_headlen(skb) - lso_header_size, PCI_DMA_TODEVICE);
737			data->addr = cpu_to_be64(dma);
738			data->lkey = cpu_to_be32(mdev->mr.key);
739			wmb();
740			data->byte_count = cpu_to_be32(skb_headlen(skb) - lso_header_size);
741		}
742		tx_info->inl = 0;
743	} else {
744		build_inline_wqe(tx_desc, skb, real_size, &vlan_tag, tx_ind, fragptr);
745		tx_info->inl = 1;
746	}
747
748	ring->prod += nr_txbb;
749
750	/* If we used a bounce buffer then copy descriptor back into place */
751	if (tx_desc == (struct mlx4_en_tx_desc *) ring->bounce_buf)
752		tx_desc = mlx4_en_bounce_to_desc(priv, ring, index, desc_size);
753
754	/* Run destructor before passing skb to HW */
755	if (likely(!skb_shared(skb)))
756		skb_orphan(skb);
757
758	/* Ensure new descirptor hits memory
759	 * before setting ownership of this descriptor to HW */
760	wmb();
761	tx_desc->ctrl.owner_opcode = op_own;
762
763	/* Ring doorbell! */
764	wmb();
765	writel(ring->doorbell_qpn, mdev->uar_map + MLX4_SEND_DOORBELL);
766
767	/* Poll CQ here */
768	mlx4_en_xmit_poll(priv, tx_ind);
769
770	return NETDEV_TX_OK;
771
772tx_drop:
773	dev_kfree_skb_any(skb);
774	priv->stats.tx_dropped++;
775	return NETDEV_TX_OK;
776}
777