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/prefetch.h>
41 #include <linux/vmalloc.h>
42 #include <linux/tcp.h>
43 #include <linux/ip.h>
44 #include <linux/ipv6.h>
45 #include <linux/moduleparam.h>
46 
47 #include "mlx4_en.h"
48 
49 int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,
50 			   struct mlx4_en_tx_ring **pring, u32 size,
51 			   u16 stride, int node, int queue_index)
52 {
53 	struct mlx4_en_dev *mdev = priv->mdev;
54 	struct mlx4_en_tx_ring *ring;
55 	int tmp;
56 	int err;
57 
58 	ring = kzalloc_node(sizeof(*ring), GFP_KERNEL, node);
59 	if (!ring) {
60 		ring = kzalloc(sizeof(*ring), GFP_KERNEL);
61 		if (!ring) {
62 			en_err(priv, "Failed allocating TX ring\n");
63 			return -ENOMEM;
64 		}
65 	}
66 
67 	ring->size = size;
68 	ring->size_mask = size - 1;
69 	ring->sp_stride = stride;
70 	ring->full_size = ring->size - HEADROOM - MAX_DESC_TXBBS;
71 
72 	tmp = size * sizeof(struct mlx4_en_tx_info);
73 	ring->tx_info = kmalloc_node(tmp, GFP_KERNEL | __GFP_NOWARN, node);
74 	if (!ring->tx_info) {
75 		ring->tx_info = vmalloc(tmp);
76 		if (!ring->tx_info) {
77 			err = -ENOMEM;
78 			goto err_ring;
79 		}
80 	}
81 
82 	en_dbg(DRV, priv, "Allocated tx_info ring at addr:%p size:%d\n",
83 		 ring->tx_info, tmp);
84 
85 	ring->bounce_buf = kmalloc_node(MAX_DESC_SIZE, GFP_KERNEL, node);
86 	if (!ring->bounce_buf) {
87 		ring->bounce_buf = kmalloc(MAX_DESC_SIZE, GFP_KERNEL);
88 		if (!ring->bounce_buf) {
89 			err = -ENOMEM;
90 			goto err_info;
91 		}
92 	}
93 	ring->buf_size = ALIGN(size * ring->sp_stride, MLX4_EN_PAGE_SIZE);
94 
95 	/* Allocate HW buffers on provided NUMA node */
96 	set_dev_node(&mdev->dev->persist->pdev->dev, node);
97 	err = mlx4_alloc_hwq_res(mdev->dev, &ring->sp_wqres, ring->buf_size);
98 	set_dev_node(&mdev->dev->persist->pdev->dev, mdev->dev->numa_node);
99 	if (err) {
100 		en_err(priv, "Failed allocating hwq resources\n");
101 		goto err_bounce;
102 	}
103 
104 	ring->buf = ring->sp_wqres.buf.direct.buf;
105 
106 	en_dbg(DRV, priv, "Allocated TX ring (addr:%p) - buf:%p size:%d buf_size:%d dma:%llx\n",
107 	       ring, ring->buf, ring->size, ring->buf_size,
108 	       (unsigned long long) ring->sp_wqres.buf.direct.map);
109 
110 	err = mlx4_qp_reserve_range(mdev->dev, 1, 1, &ring->qpn,
111 				    MLX4_RESERVE_ETH_BF_QP);
112 	if (err) {
113 		en_err(priv, "failed reserving qp for TX ring\n");
114 		goto err_hwq_res;
115 	}
116 
117 	err = mlx4_qp_alloc(mdev->dev, ring->qpn, &ring->sp_qp, GFP_KERNEL);
118 	if (err) {
119 		en_err(priv, "Failed allocating qp %d\n", ring->qpn);
120 		goto err_reserve;
121 	}
122 	ring->sp_qp.event = mlx4_en_sqp_event;
123 
124 	err = mlx4_bf_alloc(mdev->dev, &ring->bf, node);
125 	if (err) {
126 		en_dbg(DRV, priv, "working without blueflame (%d)\n", err);
127 		ring->bf.uar = &mdev->priv_uar;
128 		ring->bf.uar->map = mdev->uar_map;
129 		ring->bf_enabled = false;
130 		ring->bf_alloced = false;
131 		priv->pflags &= ~MLX4_EN_PRIV_FLAGS_BLUEFLAME;
132 	} else {
133 		ring->bf_alloced = true;
134 		ring->bf_enabled = !!(priv->pflags &
135 				      MLX4_EN_PRIV_FLAGS_BLUEFLAME);
136 	}
137 
138 	ring->hwtstamp_tx_type = priv->hwtstamp_config.tx_type;
139 	ring->queue_index = queue_index;
140 
141 	if (queue_index < priv->num_tx_rings_p_up)
142 		cpumask_set_cpu(cpumask_local_spread(queue_index,
143 						     priv->mdev->dev->numa_node),
144 				&ring->sp_affinity_mask);
145 
146 	*pring = ring;
147 	return 0;
148 
149 err_reserve:
150 	mlx4_qp_release_range(mdev->dev, ring->qpn, 1);
151 err_hwq_res:
152 	mlx4_free_hwq_res(mdev->dev, &ring->sp_wqres, ring->buf_size);
153 err_bounce:
154 	kfree(ring->bounce_buf);
155 	ring->bounce_buf = NULL;
156 err_info:
157 	kvfree(ring->tx_info);
158 	ring->tx_info = NULL;
159 err_ring:
160 	kfree(ring);
161 	*pring = NULL;
162 	return err;
163 }
164 
165 void mlx4_en_destroy_tx_ring(struct mlx4_en_priv *priv,
166 			     struct mlx4_en_tx_ring **pring)
167 {
168 	struct mlx4_en_dev *mdev = priv->mdev;
169 	struct mlx4_en_tx_ring *ring = *pring;
170 	en_dbg(DRV, priv, "Destroying tx ring, qpn: %d\n", ring->qpn);
171 
172 	if (ring->bf_alloced)
173 		mlx4_bf_free(mdev->dev, &ring->bf);
174 	mlx4_qp_remove(mdev->dev, &ring->sp_qp);
175 	mlx4_qp_free(mdev->dev, &ring->sp_qp);
176 	mlx4_qp_release_range(priv->mdev->dev, ring->qpn, 1);
177 	mlx4_free_hwq_res(mdev->dev, &ring->sp_wqres, ring->buf_size);
178 	kfree(ring->bounce_buf);
179 	ring->bounce_buf = NULL;
180 	kvfree(ring->tx_info);
181 	ring->tx_info = NULL;
182 	kfree(ring);
183 	*pring = NULL;
184 }
185 
186 int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv,
187 			     struct mlx4_en_tx_ring *ring,
188 			     int cq, int user_prio)
189 {
190 	struct mlx4_en_dev *mdev = priv->mdev;
191 	int err;
192 
193 	ring->sp_cqn = cq;
194 	ring->prod = 0;
195 	ring->cons = 0xffffffff;
196 	ring->last_nr_txbb = 1;
197 	memset(ring->tx_info, 0, ring->size * sizeof(struct mlx4_en_tx_info));
198 	memset(ring->buf, 0, ring->buf_size);
199 	ring->free_tx_desc = mlx4_en_free_tx_desc;
200 
201 	ring->sp_qp_state = MLX4_QP_STATE_RST;
202 	ring->doorbell_qpn = cpu_to_be32(ring->sp_qp.qpn << 8);
203 	ring->mr_key = cpu_to_be32(mdev->mr.key);
204 
205 	mlx4_en_fill_qp_context(priv, ring->size, ring->sp_stride, 1, 0, ring->qpn,
206 				ring->sp_cqn, user_prio, &ring->sp_context);
207 	if (ring->bf_alloced)
208 		ring->sp_context.usr_page =
209 			cpu_to_be32(mlx4_to_hw_uar_index(mdev->dev,
210 							 ring->bf.uar->index));
211 
212 	err = mlx4_qp_to_ready(mdev->dev, &ring->sp_wqres.mtt, &ring->sp_context,
213 			       &ring->sp_qp, &ring->sp_qp_state);
214 	if (!cpumask_empty(&ring->sp_affinity_mask))
215 		netif_set_xps_queue(priv->dev, &ring->sp_affinity_mask,
216 				    ring->queue_index);
217 
218 	return err;
219 }
220 
221 void mlx4_en_deactivate_tx_ring(struct mlx4_en_priv *priv,
222 				struct mlx4_en_tx_ring *ring)
223 {
224 	struct mlx4_en_dev *mdev = priv->mdev;
225 
226 	mlx4_qp_modify(mdev->dev, NULL, ring->sp_qp_state,
227 		       MLX4_QP_STATE_RST, NULL, 0, 0, &ring->sp_qp);
228 }
229 
230 static inline bool mlx4_en_is_tx_ring_full(struct mlx4_en_tx_ring *ring)
231 {
232 	return ring->prod - ring->cons > ring->full_size;
233 }
234 
235 static void mlx4_en_stamp_wqe(struct mlx4_en_priv *priv,
236 			      struct mlx4_en_tx_ring *ring, int index,
237 			      u8 owner)
238 {
239 	__be32 stamp = cpu_to_be32(STAMP_VAL | (!!owner << STAMP_SHIFT));
240 	struct mlx4_en_tx_desc *tx_desc = ring->buf + index * TXBB_SIZE;
241 	struct mlx4_en_tx_info *tx_info = &ring->tx_info[index];
242 	void *end = ring->buf + ring->buf_size;
243 	__be32 *ptr = (__be32 *)tx_desc;
244 	int i;
245 
246 	/* Optimize the common case when there are no wraparounds */
247 	if (likely((void *)tx_desc + tx_info->nr_txbb * TXBB_SIZE <= end)) {
248 		/* Stamp the freed descriptor */
249 		for (i = 0; i < tx_info->nr_txbb * TXBB_SIZE;
250 		     i += STAMP_STRIDE) {
251 			*ptr = stamp;
252 			ptr += STAMP_DWORDS;
253 		}
254 	} else {
255 		/* Stamp the freed descriptor */
256 		for (i = 0; i < tx_info->nr_txbb * TXBB_SIZE;
257 		     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 
268 
269 u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
270 			 struct mlx4_en_tx_ring *ring,
271 			 int index, u8 owner, u64 timestamp,
272 			 int napi_mode)
273 {
274 	struct mlx4_en_tx_info *tx_info = &ring->tx_info[index];
275 	struct mlx4_en_tx_desc *tx_desc = ring->buf + index * TXBB_SIZE;
276 	struct mlx4_wqe_data_seg *data = (void *) tx_desc + tx_info->data_offset;
277 	void *end = ring->buf + ring->buf_size;
278 	struct sk_buff *skb = tx_info->skb;
279 	int nr_maps = tx_info->nr_maps;
280 	int i;
281 
282 	/* We do not touch skb here, so prefetch skb->users location
283 	 * to speedup consume_skb()
284 	 */
285 	prefetchw(&skb->users);
286 
287 	if (unlikely(timestamp)) {
288 		struct skb_shared_hwtstamps hwts;
289 
290 		mlx4_en_fill_hwtstamps(priv->mdev, &hwts, timestamp);
291 		skb_tstamp_tx(skb, &hwts);
292 	}
293 
294 	/* Optimize the common case when there are no wraparounds */
295 	if (likely((void *) tx_desc + tx_info->nr_txbb * TXBB_SIZE <= end)) {
296 		if (!tx_info->inl) {
297 			if (tx_info->linear)
298 				dma_unmap_single(priv->ddev,
299 						tx_info->map0_dma,
300 						tx_info->map0_byte_count,
301 						PCI_DMA_TODEVICE);
302 			else
303 				dma_unmap_page(priv->ddev,
304 					       tx_info->map0_dma,
305 					       tx_info->map0_byte_count,
306 					       PCI_DMA_TODEVICE);
307 			for (i = 1; i < nr_maps; i++) {
308 				data++;
309 				dma_unmap_page(priv->ddev,
310 					(dma_addr_t)be64_to_cpu(data->addr),
311 					be32_to_cpu(data->byte_count),
312 					PCI_DMA_TODEVICE);
313 			}
314 		}
315 	} else {
316 		if (!tx_info->inl) {
317 			if ((void *) data >= end) {
318 				data = ring->buf + ((void *)data - end);
319 			}
320 
321 			if (tx_info->linear)
322 				dma_unmap_single(priv->ddev,
323 						tx_info->map0_dma,
324 						tx_info->map0_byte_count,
325 						PCI_DMA_TODEVICE);
326 			else
327 				dma_unmap_page(priv->ddev,
328 					       tx_info->map0_dma,
329 					       tx_info->map0_byte_count,
330 					       PCI_DMA_TODEVICE);
331 			for (i = 1; i < nr_maps; i++) {
332 				data++;
333 				/* Check for wraparound before unmapping */
334 				if ((void *) data >= end)
335 					data = ring->buf;
336 				dma_unmap_page(priv->ddev,
337 					(dma_addr_t)be64_to_cpu(data->addr),
338 					be32_to_cpu(data->byte_count),
339 					PCI_DMA_TODEVICE);
340 			}
341 		}
342 	}
343 	napi_consume_skb(skb, napi_mode);
344 
345 	return tx_info->nr_txbb;
346 }
347 
348 u32 mlx4_en_recycle_tx_desc(struct mlx4_en_priv *priv,
349 			    struct mlx4_en_tx_ring *ring,
350 			    int index, u8 owner, u64 timestamp,
351 			    int napi_mode)
352 {
353 	struct mlx4_en_tx_info *tx_info = &ring->tx_info[index];
354 	struct mlx4_en_rx_alloc frame = {
355 		.page = tx_info->page,
356 		.dma = tx_info->map0_dma,
357 		.page_offset = XDP_PACKET_HEADROOM,
358 		.page_size = PAGE_SIZE,
359 	};
360 
361 	if (!mlx4_en_rx_recycle(ring->recycle_ring, &frame)) {
362 		dma_unmap_page(priv->ddev, tx_info->map0_dma,
363 			       PAGE_SIZE, priv->frag_info[0].dma_dir);
364 		put_page(tx_info->page);
365 	}
366 
367 	return tx_info->nr_txbb;
368 }
369 
370 int mlx4_en_free_tx_buf(struct net_device *dev, struct mlx4_en_tx_ring *ring)
371 {
372 	struct mlx4_en_priv *priv = netdev_priv(dev);
373 	int cnt = 0;
374 
375 	/* Skip last polled descriptor */
376 	ring->cons += ring->last_nr_txbb;
377 	en_dbg(DRV, priv, "Freeing Tx buf - cons:0x%x prod:0x%x\n",
378 		 ring->cons, ring->prod);
379 
380 	if ((u32) (ring->prod - ring->cons) > ring->size) {
381 		if (netif_msg_tx_err(priv))
382 			en_warn(priv, "Tx consumer passed producer!\n");
383 		return 0;
384 	}
385 
386 	while (ring->cons != ring->prod) {
387 		ring->last_nr_txbb = ring->free_tx_desc(priv, ring,
388 						ring->cons & ring->size_mask,
389 						!!(ring->cons & ring->size), 0,
390 						0 /* Non-NAPI caller */);
391 		ring->cons += ring->last_nr_txbb;
392 		cnt++;
393 	}
394 
395 	if (ring->tx_queue)
396 		netdev_tx_reset_queue(ring->tx_queue);
397 
398 	if (cnt)
399 		en_dbg(DRV, priv, "Freed %d uncompleted tx descriptors\n", cnt);
400 
401 	return cnt;
402 }
403 
404 static bool mlx4_en_process_tx_cq(struct net_device *dev,
405 				  struct mlx4_en_cq *cq, int napi_budget)
406 {
407 	struct mlx4_en_priv *priv = netdev_priv(dev);
408 	struct mlx4_cq *mcq = &cq->mcq;
409 	struct mlx4_en_tx_ring *ring = priv->tx_ring[cq->type][cq->ring];
410 	struct mlx4_cqe *cqe;
411 	u16 index;
412 	u16 new_index, ring_index, stamp_index;
413 	u32 txbbs_skipped = 0;
414 	u32 txbbs_stamp = 0;
415 	u32 cons_index = mcq->cons_index;
416 	int size = cq->size;
417 	u32 size_mask = ring->size_mask;
418 	struct mlx4_cqe *buf = cq->buf;
419 	u32 packets = 0;
420 	u32 bytes = 0;
421 	int factor = priv->cqe_factor;
422 	int done = 0;
423 	int budget = priv->tx_work_limit;
424 	u32 last_nr_txbb;
425 	u32 ring_cons;
426 
427 	if (!priv->port_up)
428 		return true;
429 
430 	netdev_txq_bql_complete_prefetchw(ring->tx_queue);
431 
432 	index = cons_index & size_mask;
433 	cqe = mlx4_en_get_cqe(buf, index, priv->cqe_size) + factor;
434 	last_nr_txbb = ACCESS_ONCE(ring->last_nr_txbb);
435 	ring_cons = ACCESS_ONCE(ring->cons);
436 	ring_index = ring_cons & size_mask;
437 	stamp_index = ring_index;
438 
439 	/* Process all completed CQEs */
440 	while (XNOR(cqe->owner_sr_opcode & MLX4_CQE_OWNER_MASK,
441 			cons_index & size) && (done < budget)) {
442 		/*
443 		 * make sure we read the CQE after we read the
444 		 * ownership bit
445 		 */
446 		dma_rmb();
447 
448 		if (unlikely((cqe->owner_sr_opcode & MLX4_CQE_OPCODE_MASK) ==
449 			     MLX4_CQE_OPCODE_ERROR)) {
450 			struct mlx4_err_cqe *cqe_err = (struct mlx4_err_cqe *)cqe;
451 
452 			en_err(priv, "CQE error - vendor syndrome: 0x%x syndrome: 0x%x\n",
453 			       cqe_err->vendor_err_syndrome,
454 			       cqe_err->syndrome);
455 		}
456 
457 		/* Skip over last polled CQE */
458 		new_index = be16_to_cpu(cqe->wqe_index) & size_mask;
459 
460 		do {
461 			u64 timestamp = 0;
462 
463 			txbbs_skipped += last_nr_txbb;
464 			ring_index = (ring_index + last_nr_txbb) & size_mask;
465 
466 			if (unlikely(ring->tx_info[ring_index].ts_requested))
467 				timestamp = mlx4_en_get_cqe_ts(cqe);
468 
469 			/* free next descriptor */
470 			last_nr_txbb = ring->free_tx_desc(
471 					priv, ring, ring_index,
472 					!!((ring_cons + txbbs_skipped) &
473 					ring->size), timestamp, napi_budget);
474 
475 			mlx4_en_stamp_wqe(priv, ring, stamp_index,
476 					  !!((ring_cons + txbbs_stamp) &
477 						ring->size));
478 			stamp_index = ring_index;
479 			txbbs_stamp = txbbs_skipped;
480 			packets++;
481 			bytes += ring->tx_info[ring_index].nr_bytes;
482 		} while ((++done < budget) && (ring_index != new_index));
483 
484 		++cons_index;
485 		index = cons_index & size_mask;
486 		cqe = mlx4_en_get_cqe(buf, index, priv->cqe_size) + factor;
487 	}
488 
489 
490 	/*
491 	 * To prevent CQ overflow we first update CQ consumer and only then
492 	 * the ring consumer.
493 	 */
494 	mcq->cons_index = cons_index;
495 	mlx4_cq_set_ci(mcq);
496 	wmb();
497 
498 	/* we want to dirty this cache line once */
499 	ACCESS_ONCE(ring->last_nr_txbb) = last_nr_txbb;
500 	ACCESS_ONCE(ring->cons) = ring_cons + txbbs_skipped;
501 
502 	if (ring->free_tx_desc == mlx4_en_recycle_tx_desc)
503 		return done < budget;
504 
505 	netdev_tx_completed_queue(ring->tx_queue, packets, bytes);
506 
507 	/* Wakeup Tx queue if this stopped, and ring is not full.
508 	 */
509 	if (netif_tx_queue_stopped(ring->tx_queue) &&
510 	    !mlx4_en_is_tx_ring_full(ring)) {
511 		netif_tx_wake_queue(ring->tx_queue);
512 		ring->wake_queue++;
513 	}
514 	return done < budget;
515 }
516 
517 void mlx4_en_tx_irq(struct mlx4_cq *mcq)
518 {
519 	struct mlx4_en_cq *cq = container_of(mcq, struct mlx4_en_cq, mcq);
520 	struct mlx4_en_priv *priv = netdev_priv(cq->dev);
521 
522 	if (likely(priv->port_up))
523 		napi_schedule_irqoff(&cq->napi);
524 	else
525 		mlx4_en_arm_cq(priv, cq);
526 }
527 
528 /* TX CQ polling - called by NAPI */
529 int mlx4_en_poll_tx_cq(struct napi_struct *napi, int budget)
530 {
531 	struct mlx4_en_cq *cq = container_of(napi, struct mlx4_en_cq, napi);
532 	struct net_device *dev = cq->dev;
533 	struct mlx4_en_priv *priv = netdev_priv(dev);
534 	int clean_complete;
535 
536 	clean_complete = mlx4_en_process_tx_cq(dev, cq, budget);
537 	if (!clean_complete)
538 		return budget;
539 
540 	napi_complete(napi);
541 	mlx4_en_arm_cq(priv, cq);
542 
543 	return 0;
544 }
545 
546 static struct mlx4_en_tx_desc *mlx4_en_bounce_to_desc(struct mlx4_en_priv *priv,
547 						      struct mlx4_en_tx_ring *ring,
548 						      u32 index,
549 						      unsigned int desc_size)
550 {
551 	u32 copy = (ring->size - index) * TXBB_SIZE;
552 	int i;
553 
554 	for (i = desc_size - copy - 4; i >= 0; i -= 4) {
555 		if ((i & (TXBB_SIZE - 1)) == 0)
556 			wmb();
557 
558 		*((u32 *) (ring->buf + i)) =
559 			*((u32 *) (ring->bounce_buf + copy + i));
560 	}
561 
562 	for (i = copy - 4; i >= 4 ; i -= 4) {
563 		if ((i & (TXBB_SIZE - 1)) == 0)
564 			wmb();
565 
566 		*((u32 *) (ring->buf + index * TXBB_SIZE + i)) =
567 			*((u32 *) (ring->bounce_buf + i));
568 	}
569 
570 	/* Return real descriptor location */
571 	return ring->buf + index * TXBB_SIZE;
572 }
573 
574 /* Decide if skb can be inlined in tx descriptor to avoid dma mapping
575  *
576  * It seems strange we do not simply use skb_copy_bits().
577  * This would allow to inline all skbs iff skb->len <= inline_thold
578  *
579  * Note that caller already checked skb was not a gso packet
580  */
581 static bool is_inline(int inline_thold, const struct sk_buff *skb,
582 		      const struct skb_shared_info *shinfo,
583 		      void **pfrag)
584 {
585 	void *ptr;
586 
587 	if (skb->len > inline_thold || !inline_thold)
588 		return false;
589 
590 	if (shinfo->nr_frags == 1) {
591 		ptr = skb_frag_address_safe(&shinfo->frags[0]);
592 		if (unlikely(!ptr))
593 			return false;
594 		*pfrag = ptr;
595 		return true;
596 	}
597 	if (shinfo->nr_frags)
598 		return false;
599 	return true;
600 }
601 
602 static int inline_size(const struct sk_buff *skb)
603 {
604 	if (skb->len + CTRL_SIZE + sizeof(struct mlx4_wqe_inline_seg)
605 	    <= MLX4_INLINE_ALIGN)
606 		return ALIGN(skb->len + CTRL_SIZE +
607 			     sizeof(struct mlx4_wqe_inline_seg), 16);
608 	else
609 		return ALIGN(skb->len + CTRL_SIZE + 2 *
610 			     sizeof(struct mlx4_wqe_inline_seg), 16);
611 }
612 
613 static int get_real_size(const struct sk_buff *skb,
614 			 const struct skb_shared_info *shinfo,
615 			 struct net_device *dev,
616 			 int *lso_header_size,
617 			 bool *inline_ok,
618 			 void **pfrag)
619 {
620 	struct mlx4_en_priv *priv = netdev_priv(dev);
621 	int real_size;
622 
623 	if (shinfo->gso_size) {
624 		*inline_ok = false;
625 		if (skb->encapsulation)
626 			*lso_header_size = (skb_inner_transport_header(skb) - skb->data) + inner_tcp_hdrlen(skb);
627 		else
628 			*lso_header_size = skb_transport_offset(skb) + tcp_hdrlen(skb);
629 		real_size = CTRL_SIZE + shinfo->nr_frags * DS_SIZE +
630 			ALIGN(*lso_header_size + 4, DS_SIZE);
631 		if (unlikely(*lso_header_size != skb_headlen(skb))) {
632 			/* We add a segment for the skb linear buffer only if
633 			 * it contains data */
634 			if (*lso_header_size < skb_headlen(skb))
635 				real_size += DS_SIZE;
636 			else {
637 				if (netif_msg_tx_err(priv))
638 					en_warn(priv, "Non-linear headers\n");
639 				return 0;
640 			}
641 		}
642 	} else {
643 		*lso_header_size = 0;
644 		*inline_ok = is_inline(priv->prof->inline_thold, skb,
645 				       shinfo, pfrag);
646 
647 		if (*inline_ok)
648 			real_size = inline_size(skb);
649 		else
650 			real_size = CTRL_SIZE +
651 				    (shinfo->nr_frags + 1) * DS_SIZE;
652 	}
653 
654 	return real_size;
655 }
656 
657 static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
658 			     const struct sk_buff *skb,
659 			     const struct skb_shared_info *shinfo,
660 			     void *fragptr)
661 {
662 	struct mlx4_wqe_inline_seg *inl = &tx_desc->inl;
663 	int spc = MLX4_INLINE_ALIGN - CTRL_SIZE - sizeof *inl;
664 	unsigned int hlen = skb_headlen(skb);
665 
666 	if (skb->len <= spc) {
667 		if (likely(skb->len >= MIN_PKT_LEN)) {
668 			inl->byte_count = cpu_to_be32(1 << 31 | skb->len);
669 		} else {
670 			inl->byte_count = cpu_to_be32(1 << 31 | MIN_PKT_LEN);
671 			memset(((void *)(inl + 1)) + skb->len, 0,
672 			       MIN_PKT_LEN - skb->len);
673 		}
674 		skb_copy_from_linear_data(skb, inl + 1, hlen);
675 		if (shinfo->nr_frags)
676 			memcpy(((void *)(inl + 1)) + hlen, fragptr,
677 			       skb_frag_size(&shinfo->frags[0]));
678 
679 	} else {
680 		inl->byte_count = cpu_to_be32(1 << 31 | spc);
681 		if (hlen <= spc) {
682 			skb_copy_from_linear_data(skb, inl + 1, hlen);
683 			if (hlen < spc) {
684 				memcpy(((void *)(inl + 1)) + hlen,
685 				       fragptr, spc - hlen);
686 				fragptr +=  spc - hlen;
687 			}
688 			inl = (void *) (inl + 1) + spc;
689 			memcpy(((void *)(inl + 1)), fragptr, skb->len - spc);
690 		} else {
691 			skb_copy_from_linear_data(skb, inl + 1, spc);
692 			inl = (void *) (inl + 1) + spc;
693 			skb_copy_from_linear_data_offset(skb, spc, inl + 1,
694 							 hlen - spc);
695 			if (shinfo->nr_frags)
696 				memcpy(((void *)(inl + 1)) + hlen - spc,
697 				       fragptr,
698 				       skb_frag_size(&shinfo->frags[0]));
699 		}
700 
701 		dma_wmb();
702 		inl->byte_count = cpu_to_be32(1 << 31 | (skb->len - spc));
703 	}
704 }
705 
706 u16 mlx4_en_select_queue(struct net_device *dev, struct sk_buff *skb,
707 			 void *accel_priv, select_queue_fallback_t fallback)
708 {
709 	struct mlx4_en_priv *priv = netdev_priv(dev);
710 	u16 rings_p_up = priv->num_tx_rings_p_up;
711 	u8 up = 0;
712 
713 	if (netdev_get_num_tc(dev))
714 		return skb_tx_hash(dev, skb);
715 
716 	if (skb_vlan_tag_present(skb))
717 		up = skb_vlan_tag_get(skb) >> VLAN_PRIO_SHIFT;
718 
719 	return fallback(dev, skb) % rings_p_up + up * rings_p_up;
720 }
721 
722 static void mlx4_bf_copy(void __iomem *dst, const void *src,
723 			 unsigned int bytecnt)
724 {
725 	__iowrite64_copy(dst, src, bytecnt / 8);
726 }
727 
728 void mlx4_en_xmit_doorbell(struct mlx4_en_tx_ring *ring)
729 {
730 	wmb();
731 	/* Since there is no iowrite*_native() that writes the
732 	 * value as is, without byteswapping - using the one
733 	 * the doesn't do byteswapping in the relevant arch
734 	 * endianness.
735 	 */
736 #if defined(__LITTLE_ENDIAN)
737 	iowrite32(
738 #else
739 	iowrite32be(
740 #endif
741 		  ring->doorbell_qpn,
742 		  ring->bf.uar->map + MLX4_SEND_DOORBELL);
743 }
744 
745 static void mlx4_en_tx_write_desc(struct mlx4_en_tx_ring *ring,
746 				  struct mlx4_en_tx_desc *tx_desc,
747 				  union mlx4_wqe_qpn_vlan qpn_vlan,
748 				  int desc_size, int bf_index,
749 				  __be32 op_own, bool bf_ok,
750 				  bool send_doorbell)
751 {
752 	tx_desc->ctrl.qpn_vlan = qpn_vlan;
753 
754 	if (bf_ok) {
755 		op_own |= htonl((bf_index & 0xffff) << 8);
756 		/* Ensure new descriptor hits memory
757 		 * before setting ownership of this descriptor to HW
758 		 */
759 		dma_wmb();
760 		tx_desc->ctrl.owner_opcode = op_own;
761 
762 		wmb();
763 
764 		mlx4_bf_copy(ring->bf.reg + ring->bf.offset, &tx_desc->ctrl,
765 			     desc_size);
766 
767 		wmb();
768 
769 		ring->bf.offset ^= ring->bf.buf_size;
770 	} else {
771 		/* Ensure new descriptor hits memory
772 		 * before setting ownership of this descriptor to HW
773 		 */
774 		dma_wmb();
775 		tx_desc->ctrl.owner_opcode = op_own;
776 		if (send_doorbell)
777 			mlx4_en_xmit_doorbell(ring);
778 		else
779 			ring->xmit_more++;
780 	}
781 }
782 
783 netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
784 {
785 	struct skb_shared_info *shinfo = skb_shinfo(skb);
786 	struct mlx4_en_priv *priv = netdev_priv(dev);
787 	union mlx4_wqe_qpn_vlan	qpn_vlan = {};
788 	struct device *ddev = priv->ddev;
789 	struct mlx4_en_tx_ring *ring;
790 	struct mlx4_en_tx_desc *tx_desc;
791 	struct mlx4_wqe_data_seg *data;
792 	struct mlx4_en_tx_info *tx_info;
793 	int tx_ind = 0;
794 	int nr_txbb;
795 	int desc_size;
796 	int real_size;
797 	u32 index, bf_index;
798 	__be32 op_own;
799 	u16 vlan_proto = 0;
800 	int i_frag;
801 	int lso_header_size;
802 	void *fragptr = NULL;
803 	bool bounce = false;
804 	bool send_doorbell;
805 	bool stop_queue;
806 	bool inline_ok;
807 	u32 ring_cons;
808 	bool bf_ok;
809 
810 	tx_ind = skb_get_queue_mapping(skb);
811 	ring = priv->tx_ring[TX][tx_ind];
812 
813 	if (!priv->port_up)
814 		goto tx_drop;
815 
816 	/* fetch ring->cons far ahead before needing it to avoid stall */
817 	ring_cons = ACCESS_ONCE(ring->cons);
818 
819 	real_size = get_real_size(skb, shinfo, dev, &lso_header_size,
820 				  &inline_ok, &fragptr);
821 	if (unlikely(!real_size))
822 		goto tx_drop_count;
823 
824 	/* Align descriptor to TXBB size */
825 	desc_size = ALIGN(real_size, TXBB_SIZE);
826 	nr_txbb = desc_size / TXBB_SIZE;
827 	if (unlikely(nr_txbb > MAX_DESC_TXBBS)) {
828 		if (netif_msg_tx_err(priv))
829 			en_warn(priv, "Oversized header or SG list\n");
830 		goto tx_drop_count;
831 	}
832 
833 	bf_ok = ring->bf_enabled;
834 	if (skb_vlan_tag_present(skb)) {
835 		qpn_vlan.vlan_tag = cpu_to_be16(skb_vlan_tag_get(skb));
836 		vlan_proto = be16_to_cpu(skb->vlan_proto);
837 		if (vlan_proto == ETH_P_8021AD)
838 			qpn_vlan.ins_vlan = MLX4_WQE_CTRL_INS_SVLAN;
839 		else if (vlan_proto == ETH_P_8021Q)
840 			qpn_vlan.ins_vlan = MLX4_WQE_CTRL_INS_CVLAN;
841 		else
842 			qpn_vlan.ins_vlan = 0;
843 		bf_ok = false;
844 	}
845 
846 	netdev_txq_bql_enqueue_prefetchw(ring->tx_queue);
847 
848 	/* Track current inflight packets for performance analysis */
849 	AVG_PERF_COUNTER(priv->pstats.inflight_avg,
850 			 (u32)(ring->prod - ring_cons - 1));
851 
852 	/* Packet is good - grab an index and transmit it */
853 	index = ring->prod & ring->size_mask;
854 	bf_index = ring->prod;
855 
856 	/* See if we have enough space for whole descriptor TXBB for setting
857 	 * SW ownership on next descriptor; if not, use a bounce buffer. */
858 	if (likely(index + nr_txbb <= ring->size))
859 		tx_desc = ring->buf + index * TXBB_SIZE;
860 	else {
861 		tx_desc = (struct mlx4_en_tx_desc *) ring->bounce_buf;
862 		bounce = true;
863 		bf_ok = false;
864 	}
865 
866 	/* Save skb in tx_info ring */
867 	tx_info = &ring->tx_info[index];
868 	tx_info->skb = skb;
869 	tx_info->nr_txbb = nr_txbb;
870 
871 	data = &tx_desc->data;
872 	if (lso_header_size)
873 		data = ((void *)&tx_desc->lso + ALIGN(lso_header_size + 4,
874 						      DS_SIZE));
875 
876 	/* valid only for none inline segments */
877 	tx_info->data_offset = (void *)data - (void *)tx_desc;
878 
879 	tx_info->inl = inline_ok;
880 
881 	tx_info->linear = (lso_header_size < skb_headlen(skb) &&
882 			   !inline_ok) ? 1 : 0;
883 
884 	tx_info->nr_maps = shinfo->nr_frags + tx_info->linear;
885 	data += tx_info->nr_maps - 1;
886 
887 	if (!tx_info->inl) {
888 		dma_addr_t dma = 0;
889 		u32 byte_count = 0;
890 
891 		/* Map fragments if any */
892 		for (i_frag = shinfo->nr_frags - 1; i_frag >= 0; i_frag--) {
893 			const struct skb_frag_struct *frag;
894 
895 			frag = &shinfo->frags[i_frag];
896 			byte_count = skb_frag_size(frag);
897 			dma = skb_frag_dma_map(ddev, frag,
898 					       0, byte_count,
899 					       DMA_TO_DEVICE);
900 			if (dma_mapping_error(ddev, dma))
901 				goto tx_drop_unmap;
902 
903 			data->addr = cpu_to_be64(dma);
904 			data->lkey = ring->mr_key;
905 			dma_wmb();
906 			data->byte_count = cpu_to_be32(byte_count);
907 			--data;
908 		}
909 
910 		/* Map linear part if needed */
911 		if (tx_info->linear) {
912 			byte_count = skb_headlen(skb) - lso_header_size;
913 
914 			dma = dma_map_single(ddev, skb->data +
915 					     lso_header_size, byte_count,
916 					     PCI_DMA_TODEVICE);
917 			if (dma_mapping_error(ddev, dma))
918 				goto tx_drop_unmap;
919 
920 			data->addr = cpu_to_be64(dma);
921 			data->lkey = ring->mr_key;
922 			dma_wmb();
923 			data->byte_count = cpu_to_be32(byte_count);
924 		}
925 		/* tx completion can avoid cache line miss for common cases */
926 		tx_info->map0_dma = dma;
927 		tx_info->map0_byte_count = byte_count;
928 	}
929 
930 	/*
931 	 * For timestamping add flag to skb_shinfo and
932 	 * set flag for further reference
933 	 */
934 	tx_info->ts_requested = 0;
935 	if (unlikely(ring->hwtstamp_tx_type == HWTSTAMP_TX_ON &&
936 		     shinfo->tx_flags & SKBTX_HW_TSTAMP)) {
937 		shinfo->tx_flags |= SKBTX_IN_PROGRESS;
938 		tx_info->ts_requested = 1;
939 	}
940 
941 	/* Prepare ctrl segement apart opcode+ownership, which depends on
942 	 * whether LSO is used */
943 	tx_desc->ctrl.srcrb_flags = priv->ctrl_flags;
944 	if (likely(skb->ip_summed == CHECKSUM_PARTIAL)) {
945 		if (!skb->encapsulation)
946 			tx_desc->ctrl.srcrb_flags |= cpu_to_be32(MLX4_WQE_CTRL_IP_CSUM |
947 								 MLX4_WQE_CTRL_TCP_UDP_CSUM);
948 		else
949 			tx_desc->ctrl.srcrb_flags |= cpu_to_be32(MLX4_WQE_CTRL_IP_CSUM);
950 		ring->tx_csum++;
951 	}
952 
953 	if (priv->flags & MLX4_EN_FLAG_ENABLE_HW_LOOPBACK) {
954 		struct ethhdr *ethh;
955 
956 		/* Copy dst mac address to wqe. This allows loopback in eSwitch,
957 		 * so that VFs and PF can communicate with each other
958 		 */
959 		ethh = (struct ethhdr *)skb->data;
960 		tx_desc->ctrl.srcrb_flags16[0] = get_unaligned((__be16 *)ethh->h_dest);
961 		tx_desc->ctrl.imm = get_unaligned((__be32 *)(ethh->h_dest + 2));
962 	}
963 
964 	/* Handle LSO (TSO) packets */
965 	if (lso_header_size) {
966 		int i;
967 
968 		/* Mark opcode as LSO */
969 		op_own = cpu_to_be32(MLX4_OPCODE_LSO | (1 << 6)) |
970 			((ring->prod & ring->size) ?
971 				cpu_to_be32(MLX4_EN_BIT_DESC_OWN) : 0);
972 
973 		/* Fill in the LSO prefix */
974 		tx_desc->lso.mss_hdr_size = cpu_to_be32(
975 			shinfo->gso_size << 16 | lso_header_size);
976 
977 		/* Copy headers;
978 		 * note that we already verified that it is linear */
979 		memcpy(tx_desc->lso.header, skb->data, lso_header_size);
980 
981 		ring->tso_packets++;
982 
983 		i = ((skb->len - lso_header_size) / shinfo->gso_size) +
984 			!!((skb->len - lso_header_size) % shinfo->gso_size);
985 		tx_info->nr_bytes = skb->len + (i - 1) * lso_header_size;
986 		ring->packets += i;
987 	} else {
988 		/* Normal (Non LSO) packet */
989 		op_own = cpu_to_be32(MLX4_OPCODE_SEND) |
990 			((ring->prod & ring->size) ?
991 			 cpu_to_be32(MLX4_EN_BIT_DESC_OWN) : 0);
992 		tx_info->nr_bytes = max_t(unsigned int, skb->len, ETH_ZLEN);
993 		ring->packets++;
994 	}
995 	ring->bytes += tx_info->nr_bytes;
996 	netdev_tx_sent_queue(ring->tx_queue, tx_info->nr_bytes);
997 	AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, skb->len);
998 
999 	if (tx_info->inl)
1000 		build_inline_wqe(tx_desc, skb, shinfo, fragptr);
1001 
1002 	if (skb->encapsulation) {
1003 		union {
1004 			struct iphdr *v4;
1005 			struct ipv6hdr *v6;
1006 			unsigned char *hdr;
1007 		} ip;
1008 		u8 proto;
1009 
1010 		ip.hdr = skb_inner_network_header(skb);
1011 		proto = (ip.v4->version == 4) ? ip.v4->protocol :
1012 						ip.v6->nexthdr;
1013 
1014 		if (proto == IPPROTO_TCP || proto == IPPROTO_UDP)
1015 			op_own |= cpu_to_be32(MLX4_WQE_CTRL_IIP | MLX4_WQE_CTRL_ILP);
1016 		else
1017 			op_own |= cpu_to_be32(MLX4_WQE_CTRL_IIP);
1018 	}
1019 
1020 	ring->prod += nr_txbb;
1021 
1022 	/* If we used a bounce buffer then copy descriptor back into place */
1023 	if (unlikely(bounce))
1024 		tx_desc = mlx4_en_bounce_to_desc(priv, ring, index, desc_size);
1025 
1026 	skb_tx_timestamp(skb);
1027 
1028 	/* Check available TXBBs And 2K spare for prefetch */
1029 	stop_queue = mlx4_en_is_tx_ring_full(ring);
1030 	if (unlikely(stop_queue)) {
1031 		netif_tx_stop_queue(ring->tx_queue);
1032 		ring->queue_stopped++;
1033 	}
1034 	send_doorbell = !skb->xmit_more || netif_xmit_stopped(ring->tx_queue);
1035 
1036 	real_size = (real_size / 16) & 0x3f;
1037 
1038 	bf_ok &= desc_size <= MAX_BF && send_doorbell;
1039 
1040 	if (bf_ok)
1041 		qpn_vlan.bf_qpn = ring->doorbell_qpn | cpu_to_be32(real_size);
1042 	else
1043 		qpn_vlan.fence_size = real_size;
1044 
1045 	mlx4_en_tx_write_desc(ring, tx_desc, qpn_vlan, desc_size, bf_index,
1046 			      op_own, bf_ok, send_doorbell);
1047 
1048 	if (unlikely(stop_queue)) {
1049 		/* If queue was emptied after the if (stop_queue) , and before
1050 		 * the netif_tx_stop_queue() - need to wake the queue,
1051 		 * or else it will remain stopped forever.
1052 		 * Need a memory barrier to make sure ring->cons was not
1053 		 * updated before queue was stopped.
1054 		 */
1055 		smp_rmb();
1056 
1057 		ring_cons = ACCESS_ONCE(ring->cons);
1058 		if (unlikely(!mlx4_en_is_tx_ring_full(ring))) {
1059 			netif_tx_wake_queue(ring->tx_queue);
1060 			ring->wake_queue++;
1061 		}
1062 	}
1063 	return NETDEV_TX_OK;
1064 
1065 tx_drop_unmap:
1066 	en_err(priv, "DMA mapping error\n");
1067 
1068 	while (++i_frag < shinfo->nr_frags) {
1069 		++data;
1070 		dma_unmap_page(ddev, (dma_addr_t) be64_to_cpu(data->addr),
1071 			       be32_to_cpu(data->byte_count),
1072 			       PCI_DMA_TODEVICE);
1073 	}
1074 
1075 tx_drop_count:
1076 	ring->tx_dropped++;
1077 tx_drop:
1078 	dev_kfree_skb_any(skb);
1079 	return NETDEV_TX_OK;
1080 }
1081 
1082 netdev_tx_t mlx4_en_xmit_frame(struct mlx4_en_rx_ring *rx_ring,
1083 			       struct mlx4_en_rx_alloc *frame,
1084 			       struct net_device *dev, unsigned int length,
1085 			       int tx_ind, int *doorbell_pending)
1086 {
1087 	struct mlx4_en_priv *priv = netdev_priv(dev);
1088 	union mlx4_wqe_qpn_vlan	qpn_vlan = {};
1089 	struct mlx4_en_tx_ring *ring;
1090 	struct mlx4_en_tx_desc *tx_desc;
1091 	struct mlx4_wqe_data_seg *data;
1092 	struct mlx4_en_tx_info *tx_info;
1093 	int index, bf_index;
1094 	bool send_doorbell;
1095 	int nr_txbb = 1;
1096 	bool stop_queue;
1097 	dma_addr_t dma;
1098 	int real_size;
1099 	__be32 op_own;
1100 	u32 ring_cons;
1101 	bool bf_ok;
1102 
1103 	BUILD_BUG_ON_MSG(ALIGN(CTRL_SIZE + DS_SIZE, TXBB_SIZE) != TXBB_SIZE,
1104 			 "mlx4_en_xmit_frame requires minimum size tx desc");
1105 
1106 	ring = priv->tx_ring[TX_XDP][tx_ind];
1107 
1108 	if (!priv->port_up)
1109 		goto tx_drop;
1110 
1111 	if (mlx4_en_is_tx_ring_full(ring))
1112 		goto tx_drop_count;
1113 
1114 	/* fetch ring->cons far ahead before needing it to avoid stall */
1115 	ring_cons = READ_ONCE(ring->cons);
1116 
1117 	index = ring->prod & ring->size_mask;
1118 	tx_info = &ring->tx_info[index];
1119 
1120 	bf_ok = ring->bf_enabled;
1121 
1122 	/* Track current inflight packets for performance analysis */
1123 	AVG_PERF_COUNTER(priv->pstats.inflight_avg,
1124 			 (u32)(ring->prod - ring_cons - 1));
1125 
1126 	bf_index = ring->prod;
1127 	tx_desc = ring->buf + index * TXBB_SIZE;
1128 	data = &tx_desc->data;
1129 
1130 	dma = frame->dma;
1131 
1132 	tx_info->page = frame->page;
1133 	frame->page = NULL;
1134 	tx_info->map0_dma = dma;
1135 	tx_info->map0_byte_count = PAGE_SIZE;
1136 	tx_info->nr_txbb = nr_txbb;
1137 	tx_info->nr_bytes = max_t(unsigned int, length, ETH_ZLEN);
1138 	tx_info->data_offset = (void *)data - (void *)tx_desc;
1139 	tx_info->ts_requested = 0;
1140 	tx_info->nr_maps = 1;
1141 	tx_info->linear = 1;
1142 	tx_info->inl = 0;
1143 
1144 	dma_sync_single_range_for_device(priv->ddev, dma, frame->page_offset,
1145 					 length, PCI_DMA_TODEVICE);
1146 
1147 	data->addr = cpu_to_be64(dma + frame->page_offset);
1148 	data->lkey = ring->mr_key;
1149 	dma_wmb();
1150 	data->byte_count = cpu_to_be32(length);
1151 
1152 	/* tx completion can avoid cache line miss for common cases */
1153 	tx_desc->ctrl.srcrb_flags = priv->ctrl_flags;
1154 
1155 	op_own = cpu_to_be32(MLX4_OPCODE_SEND) |
1156 		((ring->prod & ring->size) ?
1157 		 cpu_to_be32(MLX4_EN_BIT_DESC_OWN) : 0);
1158 
1159 	rx_ring->xdp_tx++;
1160 	AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, length);
1161 
1162 	ring->prod += nr_txbb;
1163 
1164 	stop_queue = mlx4_en_is_tx_ring_full(ring);
1165 	send_doorbell = stop_queue ||
1166 				*doorbell_pending > MLX4_EN_DOORBELL_BUDGET;
1167 	bf_ok &= send_doorbell;
1168 
1169 	real_size = ((CTRL_SIZE + nr_txbb * DS_SIZE) / 16) & 0x3f;
1170 
1171 	if (bf_ok)
1172 		qpn_vlan.bf_qpn = ring->doorbell_qpn | cpu_to_be32(real_size);
1173 	else
1174 		qpn_vlan.fence_size = real_size;
1175 
1176 	mlx4_en_tx_write_desc(ring, tx_desc, qpn_vlan, TXBB_SIZE, bf_index,
1177 			      op_own, bf_ok, send_doorbell);
1178 	*doorbell_pending = send_doorbell ? 0 : *doorbell_pending + 1;
1179 
1180 	return NETDEV_TX_OK;
1181 
1182 tx_drop_count:
1183 	rx_ring->xdp_tx_full++;
1184 tx_drop:
1185 	return NETDEV_TX_BUSY;
1186 }
1187