1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright(c) 2017 - 2019 Pensando Systems, Inc */
3 
4 #include <linux/ip.h>
5 #include <linux/ipv6.h>
6 #include <linux/if_vlan.h>
7 #include <net/ip6_checksum.h>
8 
9 #include "ionic.h"
10 #include "ionic_lif.h"
11 #include "ionic_txrx.h"
12 
13 
14 static bool ionic_tx_service(struct ionic_cq *cq, struct ionic_cq_info *cq_info);
15 
16 static inline void ionic_txq_post(struct ionic_queue *q, bool ring_dbell,
17 				  ionic_desc_cb cb_func, void *cb_arg)
18 {
19 	DEBUG_STATS_TXQ_POST(q, ring_dbell);
20 
21 	ionic_q_post(q, ring_dbell, cb_func, cb_arg);
22 }
23 
24 static inline void ionic_rxq_post(struct ionic_queue *q, bool ring_dbell,
25 				  ionic_desc_cb cb_func, void *cb_arg)
26 {
27 	ionic_q_post(q, ring_dbell, cb_func, cb_arg);
28 
29 	DEBUG_STATS_RX_BUFF_CNT(q);
30 }
31 
32 static inline struct netdev_queue *q_to_ndq(struct ionic_queue *q)
33 {
34 	return netdev_get_tx_queue(q->lif->netdev, q->index);
35 }
36 
37 static void ionic_rx_buf_reset(struct ionic_buf_info *buf_info)
38 {
39 	buf_info->page = NULL;
40 	buf_info->page_offset = 0;
41 	buf_info->dma_addr = 0;
42 }
43 
44 static int ionic_rx_page_alloc(struct ionic_queue *q,
45 			       struct ionic_buf_info *buf_info)
46 {
47 	struct net_device *netdev = q->lif->netdev;
48 	struct ionic_rx_stats *stats;
49 	struct device *dev;
50 
51 	dev = q->dev;
52 	stats = q_to_rx_stats(q);
53 
54 	if (unlikely(!buf_info)) {
55 		net_err_ratelimited("%s: %s invalid buf_info in alloc\n",
56 				    netdev->name, q->name);
57 		return -EINVAL;
58 	}
59 
60 	buf_info->page = alloc_pages(IONIC_PAGE_GFP_MASK, 0);
61 	if (unlikely(!buf_info->page)) {
62 		net_err_ratelimited("%s: %s page alloc failed\n",
63 				    netdev->name, q->name);
64 		stats->alloc_err++;
65 		return -ENOMEM;
66 	}
67 	buf_info->page_offset = 0;
68 
69 	buf_info->dma_addr = dma_map_page(dev, buf_info->page, buf_info->page_offset,
70 					  IONIC_PAGE_SIZE, DMA_FROM_DEVICE);
71 	if (unlikely(dma_mapping_error(dev, buf_info->dma_addr))) {
72 		__free_pages(buf_info->page, 0);
73 		ionic_rx_buf_reset(buf_info);
74 		net_err_ratelimited("%s: %s dma map failed\n",
75 				    netdev->name, q->name);
76 		stats->dma_map_err++;
77 		return -EIO;
78 	}
79 
80 	return 0;
81 }
82 
83 static void ionic_rx_page_free(struct ionic_queue *q,
84 			       struct ionic_buf_info *buf_info)
85 {
86 	struct net_device *netdev = q->lif->netdev;
87 	struct device *dev = q->dev;
88 
89 	if (unlikely(!buf_info)) {
90 		net_err_ratelimited("%s: %s invalid buf_info in free\n",
91 				    netdev->name, q->name);
92 		return;
93 	}
94 
95 	if (!buf_info->page)
96 		return;
97 
98 	dma_unmap_page(dev, buf_info->dma_addr, IONIC_PAGE_SIZE, DMA_FROM_DEVICE);
99 	__free_pages(buf_info->page, 0);
100 	ionic_rx_buf_reset(buf_info);
101 }
102 
103 static bool ionic_rx_buf_recycle(struct ionic_queue *q,
104 				 struct ionic_buf_info *buf_info, u32 used)
105 {
106 	u32 size;
107 
108 	/* don't re-use pages allocated in low-mem condition */
109 	if (page_is_pfmemalloc(buf_info->page))
110 		return false;
111 
112 	/* don't re-use buffers from non-local numa nodes */
113 	if (page_to_nid(buf_info->page) != numa_mem_id())
114 		return false;
115 
116 	size = ALIGN(used, IONIC_PAGE_SPLIT_SZ);
117 	buf_info->page_offset += size;
118 	if (buf_info->page_offset >= IONIC_PAGE_SIZE)
119 		return false;
120 
121 	get_page(buf_info->page);
122 
123 	return true;
124 }
125 
126 static struct sk_buff *ionic_rx_frags(struct ionic_queue *q,
127 				      struct ionic_desc_info *desc_info,
128 				      struct ionic_rxq_comp *comp)
129 {
130 	struct net_device *netdev = q->lif->netdev;
131 	struct ionic_buf_info *buf_info;
132 	struct ionic_rx_stats *stats;
133 	struct device *dev = q->dev;
134 	struct sk_buff *skb;
135 	unsigned int i;
136 	u16 frag_len;
137 	u16 len;
138 
139 	stats = q_to_rx_stats(q);
140 
141 	buf_info = &desc_info->bufs[0];
142 	len = le16_to_cpu(comp->len);
143 
144 	prefetch(buf_info->page);
145 
146 	skb = napi_get_frags(&q_to_qcq(q)->napi);
147 	if (unlikely(!skb)) {
148 		net_warn_ratelimited("%s: SKB alloc failed on %s!\n",
149 				     netdev->name, q->name);
150 		stats->alloc_err++;
151 		return NULL;
152 	}
153 
154 	i = comp->num_sg_elems + 1;
155 	do {
156 		if (unlikely(!buf_info->page)) {
157 			dev_kfree_skb(skb);
158 			return NULL;
159 		}
160 
161 		frag_len = min_t(u16, len, IONIC_PAGE_SIZE - buf_info->page_offset);
162 		len -= frag_len;
163 
164 		dma_sync_single_for_cpu(dev,
165 					buf_info->dma_addr + buf_info->page_offset,
166 					frag_len, DMA_FROM_DEVICE);
167 
168 		skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
169 				buf_info->page, buf_info->page_offset, frag_len,
170 				IONIC_PAGE_SIZE);
171 
172 		if (!ionic_rx_buf_recycle(q, buf_info, frag_len)) {
173 			dma_unmap_page(dev, buf_info->dma_addr,
174 				       IONIC_PAGE_SIZE, DMA_FROM_DEVICE);
175 			ionic_rx_buf_reset(buf_info);
176 		}
177 
178 		buf_info++;
179 
180 		i--;
181 	} while (i > 0);
182 
183 	return skb;
184 }
185 
186 static struct sk_buff *ionic_rx_copybreak(struct ionic_queue *q,
187 					  struct ionic_desc_info *desc_info,
188 					  struct ionic_rxq_comp *comp)
189 {
190 	struct net_device *netdev = q->lif->netdev;
191 	struct ionic_buf_info *buf_info;
192 	struct ionic_rx_stats *stats;
193 	struct device *dev = q->dev;
194 	struct sk_buff *skb;
195 	u16 len;
196 
197 	stats = q_to_rx_stats(q);
198 
199 	buf_info = &desc_info->bufs[0];
200 	len = le16_to_cpu(comp->len);
201 
202 	skb = napi_alloc_skb(&q_to_qcq(q)->napi, len);
203 	if (unlikely(!skb)) {
204 		net_warn_ratelimited("%s: SKB alloc failed on %s!\n",
205 				     netdev->name, q->name);
206 		stats->alloc_err++;
207 		return NULL;
208 	}
209 
210 	if (unlikely(!buf_info->page)) {
211 		dev_kfree_skb(skb);
212 		return NULL;
213 	}
214 
215 	dma_sync_single_for_cpu(dev, buf_info->dma_addr + buf_info->page_offset,
216 				len, DMA_FROM_DEVICE);
217 	skb_copy_to_linear_data(skb, page_address(buf_info->page) + buf_info->page_offset, len);
218 	dma_sync_single_for_device(dev, buf_info->dma_addr + buf_info->page_offset,
219 				   len, DMA_FROM_DEVICE);
220 
221 	skb_put(skb, len);
222 	skb->protocol = eth_type_trans(skb, q->lif->netdev);
223 
224 	return skb;
225 }
226 
227 static void ionic_rx_clean(struct ionic_queue *q,
228 			   struct ionic_desc_info *desc_info,
229 			   struct ionic_cq_info *cq_info,
230 			   void *cb_arg)
231 {
232 	struct ionic_rxq_comp *comp = cq_info->rxcq;
233 	struct net_device *netdev = q->lif->netdev;
234 	struct ionic_qcq *qcq = q_to_qcq(q);
235 	struct ionic_rx_stats *stats;
236 	struct sk_buff *skb;
237 
238 	stats = q_to_rx_stats(q);
239 
240 	if (comp->status) {
241 		stats->dropped++;
242 		return;
243 	}
244 
245 	stats->pkts++;
246 	stats->bytes += le16_to_cpu(comp->len);
247 
248 	if (le16_to_cpu(comp->len) <= q->lif->rx_copybreak)
249 		skb = ionic_rx_copybreak(q, desc_info, comp);
250 	else
251 		skb = ionic_rx_frags(q, desc_info, comp);
252 
253 	if (unlikely(!skb)) {
254 		stats->dropped++;
255 		return;
256 	}
257 
258 	skb_record_rx_queue(skb, q->index);
259 
260 	if (likely(netdev->features & NETIF_F_RXHASH)) {
261 		switch (comp->pkt_type_color & IONIC_RXQ_COMP_PKT_TYPE_MASK) {
262 		case IONIC_PKT_TYPE_IPV4:
263 		case IONIC_PKT_TYPE_IPV6:
264 			skb_set_hash(skb, le32_to_cpu(comp->rss_hash),
265 				     PKT_HASH_TYPE_L3);
266 			break;
267 		case IONIC_PKT_TYPE_IPV4_TCP:
268 		case IONIC_PKT_TYPE_IPV6_TCP:
269 		case IONIC_PKT_TYPE_IPV4_UDP:
270 		case IONIC_PKT_TYPE_IPV6_UDP:
271 			skb_set_hash(skb, le32_to_cpu(comp->rss_hash),
272 				     PKT_HASH_TYPE_L4);
273 			break;
274 		}
275 	}
276 
277 	if (likely(netdev->features & NETIF_F_RXCSUM)) {
278 		if (comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_CALC) {
279 			skb->ip_summed = CHECKSUM_COMPLETE;
280 			skb->csum = (__force __wsum)le16_to_cpu(comp->csum);
281 			stats->csum_complete++;
282 		}
283 	} else {
284 		stats->csum_none++;
285 	}
286 
287 	if (unlikely((comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_TCP_BAD) ||
288 		     (comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_UDP_BAD) ||
289 		     (comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_IP_BAD)))
290 		stats->csum_error++;
291 
292 	if (likely(netdev->features & NETIF_F_HW_VLAN_CTAG_RX) &&
293 	    (comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_VLAN)) {
294 		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
295 				       le16_to_cpu(comp->vlan_tci));
296 		stats->vlan_stripped++;
297 	}
298 
299 	if (le16_to_cpu(comp->len) <= q->lif->rx_copybreak)
300 		napi_gro_receive(&qcq->napi, skb);
301 	else
302 		napi_gro_frags(&qcq->napi);
303 }
304 
305 static bool ionic_rx_service(struct ionic_cq *cq, struct ionic_cq_info *cq_info)
306 {
307 	struct ionic_rxq_comp *comp = cq_info->rxcq;
308 	struct ionic_queue *q = cq->bound_q;
309 	struct ionic_desc_info *desc_info;
310 
311 	if (!color_match(comp->pkt_type_color, cq->done_color))
312 		return false;
313 
314 	/* check for empty queue */
315 	if (q->tail_idx == q->head_idx)
316 		return false;
317 
318 	if (q->tail_idx != le16_to_cpu(comp->comp_index))
319 		return false;
320 
321 	desc_info = &q->info[q->tail_idx];
322 	q->tail_idx = (q->tail_idx + 1) & (q->num_descs - 1);
323 
324 	/* clean the related q entry, only one per qc completion */
325 	ionic_rx_clean(q, desc_info, cq_info, desc_info->cb_arg);
326 
327 	desc_info->cb = NULL;
328 	desc_info->cb_arg = NULL;
329 
330 	return true;
331 }
332 
333 void ionic_rx_fill(struct ionic_queue *q)
334 {
335 	struct net_device *netdev = q->lif->netdev;
336 	struct ionic_desc_info *desc_info;
337 	struct ionic_rxq_sg_desc *sg_desc;
338 	struct ionic_rxq_sg_elem *sg_elem;
339 	struct ionic_buf_info *buf_info;
340 	struct ionic_rxq_desc *desc;
341 	unsigned int remain_len;
342 	unsigned int frag_len;
343 	unsigned int nfrags;
344 	unsigned int i, j;
345 	unsigned int len;
346 
347 	len = netdev->mtu + ETH_HLEN + VLAN_HLEN;
348 
349 	for (i = ionic_q_space_avail(q); i; i--) {
350 		nfrags = 0;
351 		remain_len = len;
352 		desc_info = &q->info[q->head_idx];
353 		desc = desc_info->desc;
354 		buf_info = &desc_info->bufs[0];
355 
356 		if (!buf_info->page) { /* alloc a new buffer? */
357 			if (unlikely(ionic_rx_page_alloc(q, buf_info))) {
358 				desc->addr = 0;
359 				desc->len = 0;
360 				return;
361 			}
362 		}
363 
364 		/* fill main descriptor - buf[0] */
365 		desc->addr = cpu_to_le64(buf_info->dma_addr + buf_info->page_offset);
366 		frag_len = min_t(u16, len, IONIC_PAGE_SIZE - buf_info->page_offset);
367 		desc->len = cpu_to_le16(frag_len);
368 		remain_len -= frag_len;
369 		buf_info++;
370 		nfrags++;
371 
372 		/* fill sg descriptors - buf[1..n] */
373 		sg_desc = desc_info->sg_desc;
374 		for (j = 0; remain_len > 0 && j < q->max_sg_elems; j++) {
375 			sg_elem = &sg_desc->elems[j];
376 			if (!buf_info->page) { /* alloc a new sg buffer? */
377 				if (unlikely(ionic_rx_page_alloc(q, buf_info))) {
378 					sg_elem->addr = 0;
379 					sg_elem->len = 0;
380 					return;
381 				}
382 			}
383 
384 			sg_elem->addr = cpu_to_le64(buf_info->dma_addr + buf_info->page_offset);
385 			frag_len = min_t(u16, remain_len, IONIC_PAGE_SIZE - buf_info->page_offset);
386 			sg_elem->len = cpu_to_le16(frag_len);
387 			remain_len -= frag_len;
388 			buf_info++;
389 			nfrags++;
390 		}
391 
392 		/* clear end sg element as a sentinel */
393 		if (j < q->max_sg_elems) {
394 			sg_elem = &sg_desc->elems[j];
395 			memset(sg_elem, 0, sizeof(*sg_elem));
396 		}
397 
398 		desc->opcode = (nfrags > 1) ? IONIC_RXQ_DESC_OPCODE_SG :
399 					      IONIC_RXQ_DESC_OPCODE_SIMPLE;
400 		desc_info->nbufs = nfrags;
401 
402 		ionic_rxq_post(q, false, ionic_rx_clean, NULL);
403 	}
404 
405 	ionic_dbell_ring(q->lif->kern_dbpage, q->hw_type,
406 			 q->dbval | q->head_idx);
407 }
408 
409 void ionic_rx_empty(struct ionic_queue *q)
410 {
411 	struct ionic_desc_info *desc_info;
412 	struct ionic_buf_info *buf_info;
413 	unsigned int i, j;
414 
415 	for (i = 0; i < q->num_descs; i++) {
416 		desc_info = &q->info[i];
417 		for (j = 0; j < IONIC_RX_MAX_SG_ELEMS + 1; j++) {
418 			buf_info = &desc_info->bufs[j];
419 			if (buf_info->page)
420 				ionic_rx_page_free(q, buf_info);
421 		}
422 
423 		desc_info->nbufs = 0;
424 		desc_info->cb = NULL;
425 		desc_info->cb_arg = NULL;
426 	}
427 
428 	q->head_idx = 0;
429 	q->tail_idx = 0;
430 }
431 
432 static void ionic_dim_update(struct ionic_qcq *qcq)
433 {
434 	struct dim_sample dim_sample;
435 	struct ionic_lif *lif;
436 	unsigned int qi;
437 
438 	if (!qcq->intr.dim_coal_hw)
439 		return;
440 
441 	lif = qcq->q.lif;
442 	qi = qcq->cq.bound_q->index;
443 
444 	ionic_intr_coal_init(lif->ionic->idev.intr_ctrl,
445 			     lif->rxqcqs[qi]->intr.index,
446 			     qcq->intr.dim_coal_hw);
447 
448 	dim_update_sample(qcq->cq.bound_intr->rearm_count,
449 			  lif->txqstats[qi].pkts,
450 			  lif->txqstats[qi].bytes,
451 			  &dim_sample);
452 
453 	net_dim(&qcq->dim, dim_sample);
454 }
455 
456 int ionic_tx_napi(struct napi_struct *napi, int budget)
457 {
458 	struct ionic_qcq *qcq = napi_to_qcq(napi);
459 	struct ionic_cq *cq = napi_to_cq(napi);
460 	struct ionic_dev *idev;
461 	struct ionic_lif *lif;
462 	u32 work_done = 0;
463 	u32 flags = 0;
464 
465 	lif = cq->bound_q->lif;
466 	idev = &lif->ionic->idev;
467 
468 	work_done = ionic_cq_service(cq, budget,
469 				     ionic_tx_service, NULL, NULL);
470 
471 	if (work_done < budget && napi_complete_done(napi, work_done)) {
472 		ionic_dim_update(qcq);
473 		flags |= IONIC_INTR_CRED_UNMASK;
474 		cq->bound_intr->rearm_count++;
475 	}
476 
477 	if (work_done || flags) {
478 		flags |= IONIC_INTR_CRED_RESET_COALESCE;
479 		ionic_intr_credits(idev->intr_ctrl,
480 				   cq->bound_intr->index,
481 				   work_done, flags);
482 	}
483 
484 	DEBUG_STATS_NAPI_POLL(qcq, work_done);
485 
486 	return work_done;
487 }
488 
489 int ionic_rx_napi(struct napi_struct *napi, int budget)
490 {
491 	struct ionic_qcq *qcq = napi_to_qcq(napi);
492 	struct ionic_cq *cq = napi_to_cq(napi);
493 	struct ionic_dev *idev;
494 	struct ionic_lif *lif;
495 	u16 rx_fill_threshold;
496 	u32 work_done = 0;
497 	u32 flags = 0;
498 
499 	lif = cq->bound_q->lif;
500 	idev = &lif->ionic->idev;
501 
502 	work_done = ionic_cq_service(cq, budget,
503 				     ionic_rx_service, NULL, NULL);
504 
505 	rx_fill_threshold = min_t(u16, IONIC_RX_FILL_THRESHOLD,
506 				  cq->num_descs / IONIC_RX_FILL_DIV);
507 	if (work_done && ionic_q_space_avail(cq->bound_q) >= rx_fill_threshold)
508 		ionic_rx_fill(cq->bound_q);
509 
510 	if (work_done < budget && napi_complete_done(napi, work_done)) {
511 		ionic_dim_update(qcq);
512 		flags |= IONIC_INTR_CRED_UNMASK;
513 		cq->bound_intr->rearm_count++;
514 	}
515 
516 	if (work_done || flags) {
517 		flags |= IONIC_INTR_CRED_RESET_COALESCE;
518 		ionic_intr_credits(idev->intr_ctrl,
519 				   cq->bound_intr->index,
520 				   work_done, flags);
521 	}
522 
523 	DEBUG_STATS_NAPI_POLL(qcq, work_done);
524 
525 	return work_done;
526 }
527 
528 int ionic_txrx_napi(struct napi_struct *napi, int budget)
529 {
530 	struct ionic_qcq *qcq = napi_to_qcq(napi);
531 	struct ionic_cq *rxcq = napi_to_cq(napi);
532 	unsigned int qi = rxcq->bound_q->index;
533 	struct ionic_dev *idev;
534 	struct ionic_lif *lif;
535 	struct ionic_cq *txcq;
536 	u16 rx_fill_threshold;
537 	u32 rx_work_done = 0;
538 	u32 tx_work_done = 0;
539 	u32 flags = 0;
540 
541 	lif = rxcq->bound_q->lif;
542 	idev = &lif->ionic->idev;
543 	txcq = &lif->txqcqs[qi]->cq;
544 
545 	tx_work_done = ionic_cq_service(txcq, IONIC_TX_BUDGET_DEFAULT,
546 					ionic_tx_service, NULL, NULL);
547 
548 	rx_work_done = ionic_cq_service(rxcq, budget,
549 					ionic_rx_service, NULL, NULL);
550 
551 	rx_fill_threshold = min_t(u16, IONIC_RX_FILL_THRESHOLD,
552 				  rxcq->num_descs / IONIC_RX_FILL_DIV);
553 	if (rx_work_done && ionic_q_space_avail(rxcq->bound_q) >= rx_fill_threshold)
554 		ionic_rx_fill(rxcq->bound_q);
555 
556 	if (rx_work_done < budget && napi_complete_done(napi, rx_work_done)) {
557 		ionic_dim_update(qcq);
558 		flags |= IONIC_INTR_CRED_UNMASK;
559 		rxcq->bound_intr->rearm_count++;
560 	}
561 
562 	if (rx_work_done || flags) {
563 		flags |= IONIC_INTR_CRED_RESET_COALESCE;
564 		ionic_intr_credits(idev->intr_ctrl, rxcq->bound_intr->index,
565 				   tx_work_done + rx_work_done, flags);
566 	}
567 
568 	DEBUG_STATS_NAPI_POLL(qcq, rx_work_done);
569 	DEBUG_STATS_NAPI_POLL(qcq, tx_work_done);
570 
571 	return rx_work_done;
572 }
573 
574 static dma_addr_t ionic_tx_map_single(struct ionic_queue *q,
575 				      void *data, size_t len)
576 {
577 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
578 	struct device *dev = q->dev;
579 	dma_addr_t dma_addr;
580 
581 	dma_addr = dma_map_single(dev, data, len, DMA_TO_DEVICE);
582 	if (dma_mapping_error(dev, dma_addr)) {
583 		net_warn_ratelimited("%s: DMA single map failed on %s!\n",
584 				     q->lif->netdev->name, q->name);
585 		stats->dma_map_err++;
586 		return 0;
587 	}
588 	return dma_addr;
589 }
590 
591 static dma_addr_t ionic_tx_map_frag(struct ionic_queue *q,
592 				    const skb_frag_t *frag,
593 				    size_t offset, size_t len)
594 {
595 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
596 	struct device *dev = q->dev;
597 	dma_addr_t dma_addr;
598 
599 	dma_addr = skb_frag_dma_map(dev, frag, offset, len, DMA_TO_DEVICE);
600 	if (dma_mapping_error(dev, dma_addr)) {
601 		net_warn_ratelimited("%s: DMA frag map failed on %s!\n",
602 				     q->lif->netdev->name, q->name);
603 		stats->dma_map_err++;
604 	}
605 	return dma_addr;
606 }
607 
608 static int ionic_tx_map_skb(struct ionic_queue *q, struct sk_buff *skb,
609 			    struct ionic_desc_info *desc_info)
610 {
611 	struct ionic_buf_info *buf_info = desc_info->bufs;
612 	struct device *dev = q->dev;
613 	dma_addr_t dma_addr;
614 	unsigned int nfrags;
615 	skb_frag_t *frag;
616 	int frag_idx;
617 
618 	dma_addr = ionic_tx_map_single(q, skb->data, skb_headlen(skb));
619 	if (dma_mapping_error(dev, dma_addr))
620 		return -EIO;
621 	buf_info->dma_addr = dma_addr;
622 	buf_info->len = skb_headlen(skb);
623 	buf_info++;
624 
625 	frag = skb_shinfo(skb)->frags;
626 	nfrags = skb_shinfo(skb)->nr_frags;
627 	for (frag_idx = 0; frag_idx < nfrags; frag_idx++, frag++) {
628 		dma_addr = ionic_tx_map_frag(q, frag, 0, skb_frag_size(frag));
629 		if (dma_mapping_error(dev, dma_addr))
630 			goto dma_fail;
631 		buf_info->dma_addr = dma_addr;
632 		buf_info->len = skb_frag_size(frag);
633 		buf_info++;
634 	}
635 
636 	desc_info->nbufs = 1 + nfrags;
637 
638 	return 0;
639 
640 dma_fail:
641 	/* unwind the frag mappings and the head mapping */
642 	while (frag_idx > 0) {
643 		frag_idx--;
644 		buf_info--;
645 		dma_unmap_page(dev, buf_info->dma_addr,
646 			       buf_info->len, DMA_TO_DEVICE);
647 	}
648 	dma_unmap_single(dev, buf_info->dma_addr, buf_info->len, DMA_TO_DEVICE);
649 	return -EIO;
650 }
651 
652 static void ionic_tx_clean(struct ionic_queue *q,
653 			   struct ionic_desc_info *desc_info,
654 			   struct ionic_cq_info *cq_info,
655 			   void *cb_arg)
656 {
657 	struct ionic_buf_info *buf_info = desc_info->bufs;
658 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
659 	struct device *dev = q->dev;
660 	u16 queue_index;
661 	unsigned int i;
662 
663 	if (desc_info->nbufs) {
664 		dma_unmap_single(dev, (dma_addr_t)buf_info->dma_addr,
665 				 buf_info->len, DMA_TO_DEVICE);
666 		buf_info++;
667 		for (i = 1; i < desc_info->nbufs; i++, buf_info++)
668 			dma_unmap_page(dev, (dma_addr_t)buf_info->dma_addr,
669 				       buf_info->len, DMA_TO_DEVICE);
670 	}
671 
672 	if (cb_arg) {
673 		struct sk_buff *skb = cb_arg;
674 
675 		queue_index = skb_get_queue_mapping(skb);
676 		if (unlikely(__netif_subqueue_stopped(q->lif->netdev,
677 						      queue_index))) {
678 			netif_wake_subqueue(q->lif->netdev, queue_index);
679 			q->wake++;
680 		}
681 
682 		desc_info->bytes = skb->len;
683 		stats->clean++;
684 
685 		dev_consume_skb_any(skb);
686 	}
687 }
688 
689 static bool ionic_tx_service(struct ionic_cq *cq, struct ionic_cq_info *cq_info)
690 {
691 	struct ionic_txq_comp *comp = cq_info->txcq;
692 	struct ionic_queue *q = cq->bound_q;
693 	struct ionic_desc_info *desc_info;
694 	int bytes = 0;
695 	int pkts = 0;
696 	u16 index;
697 
698 	if (!color_match(comp->color, cq->done_color))
699 		return false;
700 
701 	/* clean the related q entries, there could be
702 	 * several q entries completed for each cq completion
703 	 */
704 	do {
705 		desc_info = &q->info[q->tail_idx];
706 		desc_info->bytes = 0;
707 		index = q->tail_idx;
708 		q->tail_idx = (q->tail_idx + 1) & (q->num_descs - 1);
709 		ionic_tx_clean(q, desc_info, cq_info, desc_info->cb_arg);
710 		if (desc_info->cb_arg) {
711 			pkts++;
712 			bytes += desc_info->bytes;
713 		}
714 		desc_info->cb = NULL;
715 		desc_info->cb_arg = NULL;
716 	} while (index != le16_to_cpu(comp->comp_index));
717 
718 	if (pkts && bytes)
719 		netdev_tx_completed_queue(q_to_ndq(q), pkts, bytes);
720 
721 	return true;
722 }
723 
724 void ionic_tx_flush(struct ionic_cq *cq)
725 {
726 	struct ionic_dev *idev = &cq->lif->ionic->idev;
727 	u32 work_done;
728 
729 	work_done = ionic_cq_service(cq, cq->num_descs,
730 				     ionic_tx_service, NULL, NULL);
731 	if (work_done)
732 		ionic_intr_credits(idev->intr_ctrl, cq->bound_intr->index,
733 				   work_done, IONIC_INTR_CRED_RESET_COALESCE);
734 }
735 
736 void ionic_tx_empty(struct ionic_queue *q)
737 {
738 	struct ionic_desc_info *desc_info;
739 	int bytes = 0;
740 	int pkts = 0;
741 
742 	/* walk the not completed tx entries, if any */
743 	while (q->head_idx != q->tail_idx) {
744 		desc_info = &q->info[q->tail_idx];
745 		desc_info->bytes = 0;
746 		q->tail_idx = (q->tail_idx + 1) & (q->num_descs - 1);
747 		ionic_tx_clean(q, desc_info, NULL, desc_info->cb_arg);
748 		if (desc_info->cb_arg) {
749 			pkts++;
750 			bytes += desc_info->bytes;
751 		}
752 		desc_info->cb = NULL;
753 		desc_info->cb_arg = NULL;
754 	}
755 
756 	if (pkts && bytes)
757 		netdev_tx_completed_queue(q_to_ndq(q), pkts, bytes);
758 }
759 
760 static int ionic_tx_tcp_inner_pseudo_csum(struct sk_buff *skb)
761 {
762 	int err;
763 
764 	err = skb_cow_head(skb, 0);
765 	if (err)
766 		return err;
767 
768 	if (skb->protocol == cpu_to_be16(ETH_P_IP)) {
769 		inner_ip_hdr(skb)->check = 0;
770 		inner_tcp_hdr(skb)->check =
771 			~csum_tcpudp_magic(inner_ip_hdr(skb)->saddr,
772 					   inner_ip_hdr(skb)->daddr,
773 					   0, IPPROTO_TCP, 0);
774 	} else if (skb->protocol == cpu_to_be16(ETH_P_IPV6)) {
775 		inner_tcp_hdr(skb)->check =
776 			~csum_ipv6_magic(&inner_ipv6_hdr(skb)->saddr,
777 					 &inner_ipv6_hdr(skb)->daddr,
778 					 0, IPPROTO_TCP, 0);
779 	}
780 
781 	return 0;
782 }
783 
784 static int ionic_tx_tcp_pseudo_csum(struct sk_buff *skb)
785 {
786 	int err;
787 
788 	err = skb_cow_head(skb, 0);
789 	if (err)
790 		return err;
791 
792 	if (skb->protocol == cpu_to_be16(ETH_P_IP)) {
793 		ip_hdr(skb)->check = 0;
794 		tcp_hdr(skb)->check =
795 			~csum_tcpudp_magic(ip_hdr(skb)->saddr,
796 					   ip_hdr(skb)->daddr,
797 					   0, IPPROTO_TCP, 0);
798 	} else if (skb->protocol == cpu_to_be16(ETH_P_IPV6)) {
799 		tcp_v6_gso_csum_prep(skb);
800 	}
801 
802 	return 0;
803 }
804 
805 static void ionic_tx_tso_post(struct ionic_queue *q, struct ionic_txq_desc *desc,
806 			      struct sk_buff *skb,
807 			      dma_addr_t addr, u8 nsge, u16 len,
808 			      unsigned int hdrlen, unsigned int mss,
809 			      bool outer_csum,
810 			      u16 vlan_tci, bool has_vlan,
811 			      bool start, bool done)
812 {
813 	u8 flags = 0;
814 	u64 cmd;
815 
816 	flags |= has_vlan ? IONIC_TXQ_DESC_FLAG_VLAN : 0;
817 	flags |= outer_csum ? IONIC_TXQ_DESC_FLAG_ENCAP : 0;
818 	flags |= start ? IONIC_TXQ_DESC_FLAG_TSO_SOT : 0;
819 	flags |= done ? IONIC_TXQ_DESC_FLAG_TSO_EOT : 0;
820 
821 	cmd = encode_txq_desc_cmd(IONIC_TXQ_DESC_OPCODE_TSO, flags, nsge, addr);
822 	desc->cmd = cpu_to_le64(cmd);
823 	desc->len = cpu_to_le16(len);
824 	desc->vlan_tci = cpu_to_le16(vlan_tci);
825 	desc->hdr_len = cpu_to_le16(hdrlen);
826 	desc->mss = cpu_to_le16(mss);
827 
828 	if (start) {
829 		skb_tx_timestamp(skb);
830 		netdev_tx_sent_queue(q_to_ndq(q), skb->len);
831 		ionic_txq_post(q, false, ionic_tx_clean, skb);
832 	} else {
833 		ionic_txq_post(q, done, NULL, NULL);
834 	}
835 }
836 
837 static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
838 {
839 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
840 	struct ionic_desc_info *desc_info;
841 	struct ionic_buf_info *buf_info;
842 	struct ionic_txq_sg_elem *elem;
843 	struct ionic_txq_desc *desc;
844 	unsigned int chunk_len;
845 	unsigned int frag_rem;
846 	unsigned int tso_rem;
847 	unsigned int seg_rem;
848 	dma_addr_t desc_addr;
849 	dma_addr_t frag_addr;
850 	unsigned int hdrlen;
851 	unsigned int len;
852 	unsigned int mss;
853 	bool start, done;
854 	bool outer_csum;
855 	bool has_vlan;
856 	u16 desc_len;
857 	u8 desc_nsge;
858 	u16 vlan_tci;
859 	bool encap;
860 	int err;
861 
862 	desc_info = &q->info[q->head_idx];
863 	buf_info = desc_info->bufs;
864 
865 	if (unlikely(ionic_tx_map_skb(q, skb, desc_info)))
866 		return -EIO;
867 
868 	len = skb->len;
869 	mss = skb_shinfo(skb)->gso_size;
870 	outer_csum = (skb_shinfo(skb)->gso_type & SKB_GSO_GRE_CSUM) ||
871 		     (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
872 	has_vlan = !!skb_vlan_tag_present(skb);
873 	vlan_tci = skb_vlan_tag_get(skb);
874 	encap = skb->encapsulation;
875 
876 	/* Preload inner-most TCP csum field with IP pseudo hdr
877 	 * calculated with IP length set to zero.  HW will later
878 	 * add in length to each TCP segment resulting from the TSO.
879 	 */
880 
881 	if (encap)
882 		err = ionic_tx_tcp_inner_pseudo_csum(skb);
883 	else
884 		err = ionic_tx_tcp_pseudo_csum(skb);
885 	if (err)
886 		return err;
887 
888 	if (encap)
889 		hdrlen = skb_inner_transport_header(skb) - skb->data +
890 			 inner_tcp_hdrlen(skb);
891 	else
892 		hdrlen = skb_transport_offset(skb) + tcp_hdrlen(skb);
893 
894 	tso_rem = len;
895 	seg_rem = min(tso_rem, hdrlen + mss);
896 
897 	frag_addr = 0;
898 	frag_rem = 0;
899 
900 	start = true;
901 
902 	while (tso_rem > 0) {
903 		desc = NULL;
904 		elem = NULL;
905 		desc_addr = 0;
906 		desc_len = 0;
907 		desc_nsge = 0;
908 		/* use fragments until we have enough to post a single descriptor */
909 		while (seg_rem > 0) {
910 			/* if the fragment is exhausted then move to the next one */
911 			if (frag_rem == 0) {
912 				/* grab the next fragment */
913 				frag_addr = buf_info->dma_addr;
914 				frag_rem = buf_info->len;
915 				buf_info++;
916 			}
917 			chunk_len = min(frag_rem, seg_rem);
918 			if (!desc) {
919 				/* fill main descriptor */
920 				desc = desc_info->txq_desc;
921 				elem = desc_info->txq_sg_desc->elems;
922 				desc_addr = frag_addr;
923 				desc_len = chunk_len;
924 			} else {
925 				/* fill sg descriptor */
926 				elem->addr = cpu_to_le64(frag_addr);
927 				elem->len = cpu_to_le16(chunk_len);
928 				elem++;
929 				desc_nsge++;
930 			}
931 			frag_addr += chunk_len;
932 			frag_rem -= chunk_len;
933 			tso_rem -= chunk_len;
934 			seg_rem -= chunk_len;
935 		}
936 		seg_rem = min(tso_rem, mss);
937 		done = (tso_rem == 0);
938 		/* post descriptor */
939 		ionic_tx_tso_post(q, desc, skb,
940 				  desc_addr, desc_nsge, desc_len,
941 				  hdrlen, mss, outer_csum, vlan_tci, has_vlan,
942 				  start, done);
943 		start = false;
944 		/* Buffer information is stored with the first tso descriptor */
945 		desc_info = &q->info[q->head_idx];
946 		desc_info->nbufs = 0;
947 	}
948 
949 	stats->pkts += DIV_ROUND_UP(len - hdrlen, mss);
950 	stats->bytes += len;
951 	stats->tso++;
952 	stats->tso_bytes = len;
953 
954 	return 0;
955 }
956 
957 static int ionic_tx_calc_csum(struct ionic_queue *q, struct sk_buff *skb,
958 			      struct ionic_desc_info *desc_info)
959 {
960 	struct ionic_txq_desc *desc = desc_info->txq_desc;
961 	struct ionic_buf_info *buf_info = desc_info->bufs;
962 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
963 	bool has_vlan;
964 	u8 flags = 0;
965 	bool encap;
966 	u64 cmd;
967 
968 	has_vlan = !!skb_vlan_tag_present(skb);
969 	encap = skb->encapsulation;
970 
971 	flags |= has_vlan ? IONIC_TXQ_DESC_FLAG_VLAN : 0;
972 	flags |= encap ? IONIC_TXQ_DESC_FLAG_ENCAP : 0;
973 
974 	cmd = encode_txq_desc_cmd(IONIC_TXQ_DESC_OPCODE_CSUM_PARTIAL,
975 				  flags, skb_shinfo(skb)->nr_frags,
976 				  buf_info->dma_addr);
977 	desc->cmd = cpu_to_le64(cmd);
978 	desc->len = cpu_to_le16(buf_info->len);
979 	if (has_vlan) {
980 		desc->vlan_tci = cpu_to_le16(skb_vlan_tag_get(skb));
981 		stats->vlan_inserted++;
982 	} else {
983 		desc->vlan_tci = 0;
984 	}
985 	desc->csum_start = cpu_to_le16(skb_checksum_start_offset(skb));
986 	desc->csum_offset = cpu_to_le16(skb->csum_offset);
987 
988 	if (skb_csum_is_sctp(skb))
989 		stats->crc32_csum++;
990 	else
991 		stats->csum++;
992 
993 	return 0;
994 }
995 
996 static int ionic_tx_calc_no_csum(struct ionic_queue *q, struct sk_buff *skb,
997 				 struct ionic_desc_info *desc_info)
998 {
999 	struct ionic_txq_desc *desc = desc_info->txq_desc;
1000 	struct ionic_buf_info *buf_info = desc_info->bufs;
1001 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
1002 	bool has_vlan;
1003 	u8 flags = 0;
1004 	bool encap;
1005 	u64 cmd;
1006 
1007 	has_vlan = !!skb_vlan_tag_present(skb);
1008 	encap = skb->encapsulation;
1009 
1010 	flags |= has_vlan ? IONIC_TXQ_DESC_FLAG_VLAN : 0;
1011 	flags |= encap ? IONIC_TXQ_DESC_FLAG_ENCAP : 0;
1012 
1013 	cmd = encode_txq_desc_cmd(IONIC_TXQ_DESC_OPCODE_CSUM_NONE,
1014 				  flags, skb_shinfo(skb)->nr_frags,
1015 				  buf_info->dma_addr);
1016 	desc->cmd = cpu_to_le64(cmd);
1017 	desc->len = cpu_to_le16(buf_info->len);
1018 	if (has_vlan) {
1019 		desc->vlan_tci = cpu_to_le16(skb_vlan_tag_get(skb));
1020 		stats->vlan_inserted++;
1021 	} else {
1022 		desc->vlan_tci = 0;
1023 	}
1024 	desc->csum_start = 0;
1025 	desc->csum_offset = 0;
1026 
1027 	stats->csum_none++;
1028 
1029 	return 0;
1030 }
1031 
1032 static int ionic_tx_skb_frags(struct ionic_queue *q, struct sk_buff *skb,
1033 			      struct ionic_desc_info *desc_info)
1034 {
1035 	struct ionic_txq_sg_desc *sg_desc = desc_info->txq_sg_desc;
1036 	struct ionic_buf_info *buf_info = &desc_info->bufs[1];
1037 	struct ionic_txq_sg_elem *elem = sg_desc->elems;
1038 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
1039 	unsigned int i;
1040 
1041 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++, buf_info++, elem++) {
1042 		elem->addr = cpu_to_le64(buf_info->dma_addr);
1043 		elem->len = cpu_to_le16(buf_info->len);
1044 	}
1045 
1046 	stats->frags += skb_shinfo(skb)->nr_frags;
1047 
1048 	return 0;
1049 }
1050 
1051 static int ionic_tx(struct ionic_queue *q, struct sk_buff *skb)
1052 {
1053 	struct ionic_desc_info *desc_info = &q->info[q->head_idx];
1054 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
1055 	int err;
1056 
1057 	if (unlikely(ionic_tx_map_skb(q, skb, desc_info)))
1058 		return -EIO;
1059 
1060 	/* set up the initial descriptor */
1061 	if (skb->ip_summed == CHECKSUM_PARTIAL)
1062 		err = ionic_tx_calc_csum(q, skb, desc_info);
1063 	else
1064 		err = ionic_tx_calc_no_csum(q, skb, desc_info);
1065 	if (err)
1066 		return err;
1067 
1068 	/* add frags */
1069 	err = ionic_tx_skb_frags(q, skb, desc_info);
1070 	if (err)
1071 		return err;
1072 
1073 	skb_tx_timestamp(skb);
1074 	stats->pkts++;
1075 	stats->bytes += skb->len;
1076 
1077 	netdev_tx_sent_queue(q_to_ndq(q), skb->len);
1078 	ionic_txq_post(q, !netdev_xmit_more(), ionic_tx_clean, skb);
1079 
1080 	return 0;
1081 }
1082 
1083 static int ionic_tx_descs_needed(struct ionic_queue *q, struct sk_buff *skb)
1084 {
1085 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
1086 	int err;
1087 
1088 	/* If TSO, need roundup(skb->len/mss) descs */
1089 	if (skb_is_gso(skb))
1090 		return (skb->len / skb_shinfo(skb)->gso_size) + 1;
1091 
1092 	/* If non-TSO, just need 1 desc and nr_frags sg elems */
1093 	if (skb_shinfo(skb)->nr_frags <= q->max_sg_elems)
1094 		return 1;
1095 
1096 	/* Too many frags, so linearize */
1097 	err = skb_linearize(skb);
1098 	if (err)
1099 		return err;
1100 
1101 	stats->linearize++;
1102 
1103 	/* Need 1 desc and zero sg elems */
1104 	return 1;
1105 }
1106 
1107 static int ionic_maybe_stop_tx(struct ionic_queue *q, int ndescs)
1108 {
1109 	int stopped = 0;
1110 
1111 	if (unlikely(!ionic_q_has_space(q, ndescs))) {
1112 		netif_stop_subqueue(q->lif->netdev, q->index);
1113 		q->stop++;
1114 		stopped = 1;
1115 
1116 		/* Might race with ionic_tx_clean, check again */
1117 		smp_rmb();
1118 		if (ionic_q_has_space(q, ndescs)) {
1119 			netif_wake_subqueue(q->lif->netdev, q->index);
1120 			stopped = 0;
1121 		}
1122 	}
1123 
1124 	return stopped;
1125 }
1126 
1127 netdev_tx_t ionic_start_xmit(struct sk_buff *skb, struct net_device *netdev)
1128 {
1129 	u16 queue_index = skb_get_queue_mapping(skb);
1130 	struct ionic_lif *lif = netdev_priv(netdev);
1131 	struct ionic_queue *q;
1132 	int ndescs;
1133 	int err;
1134 
1135 	if (unlikely(!test_bit(IONIC_LIF_F_UP, lif->state))) {
1136 		dev_kfree_skb(skb);
1137 		return NETDEV_TX_OK;
1138 	}
1139 
1140 	if (unlikely(queue_index >= lif->nxqs))
1141 		queue_index = 0;
1142 	q = &lif->txqcqs[queue_index]->q;
1143 
1144 	ndescs = ionic_tx_descs_needed(q, skb);
1145 	if (ndescs < 0)
1146 		goto err_out_drop;
1147 
1148 	if (unlikely(ionic_maybe_stop_tx(q, ndescs)))
1149 		return NETDEV_TX_BUSY;
1150 
1151 	if (skb_is_gso(skb))
1152 		err = ionic_tx_tso(q, skb);
1153 	else
1154 		err = ionic_tx(q, skb);
1155 
1156 	if (err)
1157 		goto err_out_drop;
1158 
1159 	/* Stop the queue if there aren't descriptors for the next packet.
1160 	 * Since our SG lists per descriptor take care of most of the possible
1161 	 * fragmentation, we don't need to have many descriptors available.
1162 	 */
1163 	ionic_maybe_stop_tx(q, 4);
1164 
1165 	return NETDEV_TX_OK;
1166 
1167 err_out_drop:
1168 	q->stop++;
1169 	q->drop++;
1170 	dev_kfree_skb(skb);
1171 	return NETDEV_TX_OK;
1172 }
1173