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 static void ionic_rx_clean(struct ionic_queue *q, struct ionic_desc_info *desc_info,
14 			   struct ionic_cq_info *cq_info, void *cb_arg);
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_to_qcq(q), q->head->desc, 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_to_qcq(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 struct sk_buff *ionic_rx_skb_alloc(struct ionic_queue *q,
38 					  unsigned int len, bool frags)
39 {
40 	struct ionic_lif *lif = q->lif;
41 	struct ionic_rx_stats *stats;
42 	struct net_device *netdev;
43 	struct sk_buff *skb;
44 
45 	netdev = lif->netdev;
46 	stats = q_to_rx_stats(q);
47 
48 	if (frags)
49 		skb = napi_get_frags(&q_to_qcq(q)->napi);
50 	else
51 		skb = netdev_alloc_skb_ip_align(netdev, len);
52 
53 	if (unlikely(!skb)) {
54 		net_warn_ratelimited("%s: SKB alloc failed on %s!\n",
55 				     netdev->name, q->name);
56 		stats->alloc_err++;
57 		return NULL;
58 	}
59 
60 	return skb;
61 }
62 
63 static struct sk_buff *ionic_rx_frags(struct ionic_queue *q,
64 				      struct ionic_desc_info *desc_info,
65 				      struct ionic_cq_info *cq_info)
66 {
67 	struct ionic_rxq_comp *comp = cq_info->cq_desc;
68 	struct device *dev = q->lif->ionic->dev;
69 	struct ionic_page_info *page_info;
70 	struct sk_buff *skb;
71 	unsigned int i;
72 	u16 frag_len;
73 	u16 len;
74 
75 	page_info = &desc_info->pages[0];
76 	len = le16_to_cpu(comp->len);
77 
78 	prefetch(page_address(page_info->page) + NET_IP_ALIGN);
79 
80 	skb = ionic_rx_skb_alloc(q, len, true);
81 	if (unlikely(!skb))
82 		return NULL;
83 
84 	i = comp->num_sg_elems + 1;
85 	do {
86 		if (unlikely(!page_info->page)) {
87 			struct napi_struct *napi = &q_to_qcq(q)->napi;
88 
89 			napi->skb = NULL;
90 			dev_kfree_skb(skb);
91 			return NULL;
92 		}
93 
94 		frag_len = min(len, (u16)PAGE_SIZE);
95 		len -= frag_len;
96 
97 		dma_unmap_page(dev, dma_unmap_addr(page_info, dma_addr),
98 			       PAGE_SIZE, DMA_FROM_DEVICE);
99 		skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
100 				page_info->page, 0, frag_len, PAGE_SIZE);
101 		page_info->page = NULL;
102 		page_info++;
103 		i--;
104 	} while (i > 0);
105 
106 	return skb;
107 }
108 
109 static struct sk_buff *ionic_rx_copybreak(struct ionic_queue *q,
110 					  struct ionic_desc_info *desc_info,
111 					  struct ionic_cq_info *cq_info)
112 {
113 	struct ionic_rxq_comp *comp = cq_info->cq_desc;
114 	struct device *dev = q->lif->ionic->dev;
115 	struct ionic_page_info *page_info;
116 	struct sk_buff *skb;
117 	u16 len;
118 
119 	page_info = &desc_info->pages[0];
120 	len = le16_to_cpu(comp->len);
121 
122 	skb = ionic_rx_skb_alloc(q, len, false);
123 	if (unlikely(!skb))
124 		return NULL;
125 
126 	if (unlikely(!page_info->page)) {
127 		dev_kfree_skb(skb);
128 		return NULL;
129 	}
130 
131 	dma_sync_single_for_cpu(dev, dma_unmap_addr(page_info, dma_addr),
132 				len, DMA_FROM_DEVICE);
133 	skb_copy_to_linear_data(skb, page_address(page_info->page), len);
134 	dma_sync_single_for_device(dev, dma_unmap_addr(page_info, dma_addr),
135 				   len, DMA_FROM_DEVICE);
136 
137 	skb_put(skb, len);
138 	skb->protocol = eth_type_trans(skb, q->lif->netdev);
139 
140 	return skb;
141 }
142 
143 static void ionic_rx_clean(struct ionic_queue *q, struct ionic_desc_info *desc_info,
144 			   struct ionic_cq_info *cq_info, void *cb_arg)
145 {
146 	struct ionic_rxq_comp *comp = cq_info->cq_desc;
147 	struct ionic_qcq *qcq = q_to_qcq(q);
148 	struct ionic_rx_stats *stats;
149 	struct net_device *netdev;
150 	struct sk_buff *skb;
151 
152 	stats = q_to_rx_stats(q);
153 	netdev = q->lif->netdev;
154 
155 	if (comp->status) {
156 		stats->dropped++;
157 		return;
158 	}
159 
160 	/* no packet processing while resetting */
161 	if (unlikely(test_bit(IONIC_LIF_F_QUEUE_RESET, q->lif->state))) {
162 		stats->dropped++;
163 		return;
164 	}
165 
166 	stats->pkts++;
167 	stats->bytes += le16_to_cpu(comp->len);
168 
169 	if (le16_to_cpu(comp->len) <= q->lif->rx_copybreak)
170 		skb = ionic_rx_copybreak(q, desc_info, cq_info);
171 	else
172 		skb = ionic_rx_frags(q, desc_info, cq_info);
173 
174 	if (unlikely(!skb)) {
175 		stats->dropped++;
176 		return;
177 	}
178 
179 	skb_record_rx_queue(skb, q->index);
180 
181 	if (likely(netdev->features & NETIF_F_RXHASH)) {
182 		switch (comp->pkt_type_color & IONIC_RXQ_COMP_PKT_TYPE_MASK) {
183 		case IONIC_PKT_TYPE_IPV4:
184 		case IONIC_PKT_TYPE_IPV6:
185 			skb_set_hash(skb, le32_to_cpu(comp->rss_hash),
186 				     PKT_HASH_TYPE_L3);
187 			break;
188 		case IONIC_PKT_TYPE_IPV4_TCP:
189 		case IONIC_PKT_TYPE_IPV6_TCP:
190 		case IONIC_PKT_TYPE_IPV4_UDP:
191 		case IONIC_PKT_TYPE_IPV6_UDP:
192 			skb_set_hash(skb, le32_to_cpu(comp->rss_hash),
193 				     PKT_HASH_TYPE_L4);
194 			break;
195 		}
196 	}
197 
198 	if (likely(netdev->features & NETIF_F_RXCSUM)) {
199 		if (comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_CALC) {
200 			skb->ip_summed = CHECKSUM_COMPLETE;
201 			skb->csum = (__wsum)le16_to_cpu(comp->csum);
202 			stats->csum_complete++;
203 		}
204 	} else {
205 		stats->csum_none++;
206 	}
207 
208 	if (unlikely((comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_TCP_BAD) ||
209 		     (comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_UDP_BAD) ||
210 		     (comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_IP_BAD)))
211 		stats->csum_error++;
212 
213 	if (likely(netdev->features & NETIF_F_HW_VLAN_CTAG_RX)) {
214 		if (comp->csum_flags & IONIC_RXQ_COMP_CSUM_F_VLAN)
215 			__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
216 					       le16_to_cpu(comp->vlan_tci));
217 	}
218 
219 	if (le16_to_cpu(comp->len) <= q->lif->rx_copybreak)
220 		napi_gro_receive(&qcq->napi, skb);
221 	else
222 		napi_gro_frags(&qcq->napi);
223 }
224 
225 static bool ionic_rx_service(struct ionic_cq *cq, struct ionic_cq_info *cq_info)
226 {
227 	struct ionic_rxq_comp *comp = cq_info->cq_desc;
228 	struct ionic_queue *q = cq->bound_q;
229 	struct ionic_desc_info *desc_info;
230 
231 	if (!color_match(comp->pkt_type_color, cq->done_color))
232 		return false;
233 
234 	/* check for empty queue */
235 	if (q->tail->index == q->head->index)
236 		return false;
237 
238 	desc_info = q->tail;
239 	if (desc_info->index != le16_to_cpu(comp->comp_index))
240 		return false;
241 
242 	q->tail = desc_info->next;
243 
244 	/* clean the related q entry, only one per qc completion */
245 	ionic_rx_clean(q, desc_info, cq_info, desc_info->cb_arg);
246 
247 	desc_info->cb = NULL;
248 	desc_info->cb_arg = NULL;
249 
250 	return true;
251 }
252 
253 static u32 ionic_rx_walk_cq(struct ionic_cq *rxcq, u32 limit)
254 {
255 	u32 work_done = 0;
256 
257 	while (ionic_rx_service(rxcq, rxcq->tail)) {
258 		if (rxcq->tail->last)
259 			rxcq->done_color = !rxcq->done_color;
260 		rxcq->tail = rxcq->tail->next;
261 		DEBUG_STATS_CQE_CNT(rxcq);
262 
263 		if (++work_done >= limit)
264 			break;
265 	}
266 
267 	return work_done;
268 }
269 
270 void ionic_rx_flush(struct ionic_cq *cq)
271 {
272 	struct ionic_dev *idev = &cq->lif->ionic->idev;
273 	u32 work_done;
274 
275 	work_done = ionic_rx_walk_cq(cq, cq->num_descs);
276 
277 	if (work_done)
278 		ionic_intr_credits(idev->intr_ctrl, cq->bound_intr->index,
279 				   work_done, IONIC_INTR_CRED_RESET_COALESCE);
280 }
281 
282 static struct page *ionic_rx_page_alloc(struct ionic_queue *q,
283 					dma_addr_t *dma_addr)
284 {
285 	struct ionic_lif *lif = q->lif;
286 	struct ionic_rx_stats *stats;
287 	struct net_device *netdev;
288 	struct device *dev;
289 	struct page *page;
290 
291 	netdev = lif->netdev;
292 	dev = lif->ionic->dev;
293 	stats = q_to_rx_stats(q);
294 	page = alloc_page(GFP_ATOMIC);
295 	if (unlikely(!page)) {
296 		net_err_ratelimited("%s: Page alloc failed on %s!\n",
297 				    netdev->name, q->name);
298 		stats->alloc_err++;
299 		return NULL;
300 	}
301 
302 	*dma_addr = dma_map_page(dev, page, 0, PAGE_SIZE, DMA_FROM_DEVICE);
303 	if (unlikely(dma_mapping_error(dev, *dma_addr))) {
304 		__free_page(page);
305 		net_err_ratelimited("%s: DMA single map failed on %s!\n",
306 				    netdev->name, q->name);
307 		stats->dma_map_err++;
308 		return NULL;
309 	}
310 
311 	return page;
312 }
313 
314 static void ionic_rx_page_free(struct ionic_queue *q, struct page *page,
315 			       dma_addr_t dma_addr)
316 {
317 	struct ionic_lif *lif = q->lif;
318 	struct net_device *netdev;
319 	struct device *dev;
320 
321 	netdev = lif->netdev;
322 	dev = lif->ionic->dev;
323 
324 	if (unlikely(!page)) {
325 		net_err_ratelimited("%s: Trying to free unallocated buffer on %s!\n",
326 				    netdev->name, q->name);
327 		return;
328 	}
329 
330 	dma_unmap_page(dev, dma_addr, PAGE_SIZE, DMA_FROM_DEVICE);
331 
332 	__free_page(page);
333 }
334 
335 #define IONIC_RX_RING_DOORBELL_STRIDE		((1 << 5) - 1)
336 #define IONIC_RX_RING_HEAD_BUF_SZ		2048
337 
338 void ionic_rx_fill(struct ionic_queue *q)
339 {
340 	struct net_device *netdev = q->lif->netdev;
341 	struct ionic_desc_info *desc_info;
342 	struct ionic_page_info *page_info;
343 	struct ionic_rxq_sg_desc *sg_desc;
344 	struct ionic_rxq_sg_elem *sg_elem;
345 	struct ionic_rxq_desc *desc;
346 	unsigned int remain_len;
347 	unsigned int seg_len;
348 	unsigned int nfrags;
349 	bool ring_doorbell;
350 	unsigned int i, j;
351 	unsigned int len;
352 
353 	len = netdev->mtu + ETH_HLEN;
354 	nfrags = round_up(len, PAGE_SIZE) / PAGE_SIZE;
355 
356 	for (i = ionic_q_space_avail(q); i; i--) {
357 		remain_len = len;
358 		desc_info = q->head;
359 		desc = desc_info->desc;
360 		sg_desc = desc_info->sg_desc;
361 		page_info = &desc_info->pages[0];
362 
363 		if (page_info->page) { /* recycle the buffer */
364 			ring_doorbell = ((q->head->index + 1) &
365 					IONIC_RX_RING_DOORBELL_STRIDE) == 0;
366 			ionic_rxq_post(q, ring_doorbell, ionic_rx_clean, NULL);
367 			continue;
368 		}
369 
370 		/* fill main descriptor - pages[0] */
371 		desc->opcode = (nfrags > 1) ? IONIC_RXQ_DESC_OPCODE_SG :
372 					      IONIC_RXQ_DESC_OPCODE_SIMPLE;
373 		desc_info->npages = nfrags;
374 		page_info->page = ionic_rx_page_alloc(q, &page_info->dma_addr);
375 		if (unlikely(!page_info->page)) {
376 			desc->addr = 0;
377 			desc->len = 0;
378 			return;
379 		}
380 		desc->addr = cpu_to_le64(page_info->dma_addr);
381 		seg_len = min_t(unsigned int, PAGE_SIZE, len);
382 		desc->len = cpu_to_le16(seg_len);
383 		remain_len -= seg_len;
384 		page_info++;
385 
386 		/* fill sg descriptors - pages[1..n] */
387 		for (j = 0; j < nfrags - 1; j++) {
388 			if (page_info->page) /* recycle the sg buffer */
389 				continue;
390 
391 			sg_elem = &sg_desc->elems[j];
392 			page_info->page = ionic_rx_page_alloc(q, &page_info->dma_addr);
393 			if (unlikely(!page_info->page)) {
394 				sg_elem->addr = 0;
395 				sg_elem->len = 0;
396 				return;
397 			}
398 			sg_elem->addr = cpu_to_le64(page_info->dma_addr);
399 			seg_len = min_t(unsigned int, PAGE_SIZE, remain_len);
400 			sg_elem->len = cpu_to_le16(seg_len);
401 			remain_len -= seg_len;
402 			page_info++;
403 		}
404 
405 		ring_doorbell = ((q->head->index + 1) &
406 				IONIC_RX_RING_DOORBELL_STRIDE) == 0;
407 		ionic_rxq_post(q, ring_doorbell, ionic_rx_clean, NULL);
408 	}
409 }
410 
411 static void ionic_rx_fill_cb(void *arg)
412 {
413 	ionic_rx_fill(arg);
414 }
415 
416 void ionic_rx_empty(struct ionic_queue *q)
417 {
418 	struct ionic_desc_info *cur;
419 	struct ionic_rxq_desc *desc;
420 	unsigned int i;
421 
422 	for (cur = q->tail; cur != q->head; cur = cur->next) {
423 		desc = cur->desc;
424 		desc->addr = 0;
425 		desc->len = 0;
426 
427 		for (i = 0; i < cur->npages; i++) {
428 			if (likely(cur->pages[i].page)) {
429 				ionic_rx_page_free(q, cur->pages[i].page,
430 						   cur->pages[i].dma_addr);
431 				cur->pages[i].page = NULL;
432 				cur->pages[i].dma_addr = 0;
433 			}
434 		}
435 
436 		cur->cb_arg = NULL;
437 	}
438 }
439 
440 int ionic_rx_napi(struct napi_struct *napi, int budget)
441 {
442 	struct ionic_qcq *qcq = napi_to_qcq(napi);
443 	struct ionic_cq *rxcq = napi_to_cq(napi);
444 	unsigned int qi = rxcq->bound_q->index;
445 	struct ionic_dev *idev;
446 	struct ionic_lif *lif;
447 	struct ionic_cq *txcq;
448 	u32 work_done = 0;
449 	u32 flags = 0;
450 
451 	lif = rxcq->bound_q->lif;
452 	idev = &lif->ionic->idev;
453 	txcq = &lif->txqcqs[qi].qcq->cq;
454 
455 	ionic_tx_flush(txcq);
456 
457 	work_done = ionic_rx_walk_cq(rxcq, budget);
458 
459 	if (work_done)
460 		ionic_rx_fill_cb(rxcq->bound_q);
461 
462 	if (work_done < budget && napi_complete_done(napi, work_done)) {
463 		flags |= IONIC_INTR_CRED_UNMASK;
464 		DEBUG_STATS_INTR_REARM(rxcq->bound_intr);
465 	}
466 
467 	if (work_done || flags) {
468 		flags |= IONIC_INTR_CRED_RESET_COALESCE;
469 		ionic_intr_credits(idev->intr_ctrl, rxcq->bound_intr->index,
470 				   work_done, flags);
471 	}
472 
473 	DEBUG_STATS_NAPI_POLL(qcq, work_done);
474 
475 	return work_done;
476 }
477 
478 static dma_addr_t ionic_tx_map_single(struct ionic_queue *q, void *data, size_t len)
479 {
480 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
481 	struct device *dev = q->lif->ionic->dev;
482 	dma_addr_t dma_addr;
483 
484 	dma_addr = dma_map_single(dev, data, len, DMA_TO_DEVICE);
485 	if (dma_mapping_error(dev, dma_addr)) {
486 		net_warn_ratelimited("%s: DMA single map failed on %s!\n",
487 				     q->lif->netdev->name, q->name);
488 		stats->dma_map_err++;
489 		return 0;
490 	}
491 	return dma_addr;
492 }
493 
494 static dma_addr_t ionic_tx_map_frag(struct ionic_queue *q, const skb_frag_t *frag,
495 				    size_t offset, size_t len)
496 {
497 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
498 	struct device *dev = q->lif->ionic->dev;
499 	dma_addr_t dma_addr;
500 
501 	dma_addr = skb_frag_dma_map(dev, frag, offset, len, DMA_TO_DEVICE);
502 	if (dma_mapping_error(dev, dma_addr)) {
503 		net_warn_ratelimited("%s: DMA frag map failed on %s!\n",
504 				     q->lif->netdev->name, q->name);
505 		stats->dma_map_err++;
506 	}
507 	return dma_addr;
508 }
509 
510 static void ionic_tx_clean(struct ionic_queue *q, struct ionic_desc_info *desc_info,
511 			   struct ionic_cq_info *cq_info, void *cb_arg)
512 {
513 	struct ionic_txq_sg_desc *sg_desc = desc_info->sg_desc;
514 	struct ionic_txq_sg_elem *elem = sg_desc->elems;
515 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
516 	struct ionic_txq_desc *desc = desc_info->desc;
517 	struct device *dev = q->lif->ionic->dev;
518 	u8 opcode, flags, nsge;
519 	u16 queue_index;
520 	unsigned int i;
521 	u64 addr;
522 
523 	decode_txq_desc_cmd(le64_to_cpu(desc->cmd),
524 			    &opcode, &flags, &nsge, &addr);
525 
526 	/* use unmap_single only if either this is not TSO,
527 	 * or this is first descriptor of a TSO
528 	 */
529 	if (opcode != IONIC_TXQ_DESC_OPCODE_TSO ||
530 	    flags & IONIC_TXQ_DESC_FLAG_TSO_SOT)
531 		dma_unmap_single(dev, (dma_addr_t)addr,
532 				 le16_to_cpu(desc->len), DMA_TO_DEVICE);
533 	else
534 		dma_unmap_page(dev, (dma_addr_t)addr,
535 			       le16_to_cpu(desc->len), DMA_TO_DEVICE);
536 
537 	for (i = 0; i < nsge; i++, elem++)
538 		dma_unmap_page(dev, (dma_addr_t)le64_to_cpu(elem->addr),
539 			       le16_to_cpu(elem->len), DMA_TO_DEVICE);
540 
541 	if (cb_arg) {
542 		struct sk_buff *skb = cb_arg;
543 		u32 len = skb->len;
544 
545 		queue_index = skb_get_queue_mapping(skb);
546 		if (unlikely(__netif_subqueue_stopped(q->lif->netdev,
547 						      queue_index))) {
548 			netif_wake_subqueue(q->lif->netdev, queue_index);
549 			q->wake++;
550 		}
551 		dev_kfree_skb_any(skb);
552 		stats->clean++;
553 		netdev_tx_completed_queue(q_to_ndq(q), 1, len);
554 	}
555 }
556 
557 void ionic_tx_flush(struct ionic_cq *cq)
558 {
559 	struct ionic_txq_comp *comp = cq->tail->cq_desc;
560 	struct ionic_dev *idev = &cq->lif->ionic->idev;
561 	struct ionic_queue *q = cq->bound_q;
562 	struct ionic_desc_info *desc_info;
563 	unsigned int work_done = 0;
564 
565 	/* walk the completed cq entries */
566 	while (work_done < cq->num_descs &&
567 	       color_match(comp->color, cq->done_color)) {
568 
569 		/* clean the related q entries, there could be
570 		 * several q entries completed for each cq completion
571 		 */
572 		do {
573 			desc_info = q->tail;
574 			q->tail = desc_info->next;
575 			ionic_tx_clean(q, desc_info, cq->tail,
576 				       desc_info->cb_arg);
577 			desc_info->cb = NULL;
578 			desc_info->cb_arg = NULL;
579 		} while (desc_info->index != le16_to_cpu(comp->comp_index));
580 
581 		if (cq->tail->last)
582 			cq->done_color = !cq->done_color;
583 
584 		cq->tail = cq->tail->next;
585 		comp = cq->tail->cq_desc;
586 		DEBUG_STATS_CQE_CNT(cq);
587 
588 		work_done++;
589 	}
590 
591 	if (work_done)
592 		ionic_intr_credits(idev->intr_ctrl, cq->bound_intr->index,
593 				   work_done, 0);
594 }
595 
596 void ionic_tx_empty(struct ionic_queue *q)
597 {
598 	struct ionic_desc_info *desc_info;
599 	int done = 0;
600 
601 	/* walk the not completed tx entries, if any */
602 	while (q->head != q->tail) {
603 		desc_info = q->tail;
604 		q->tail = desc_info->next;
605 		ionic_tx_clean(q, desc_info, NULL, desc_info->cb_arg);
606 		desc_info->cb = NULL;
607 		desc_info->cb_arg = NULL;
608 		done++;
609 	}
610 }
611 
612 static int ionic_tx_tcp_inner_pseudo_csum(struct sk_buff *skb)
613 {
614 	int err;
615 
616 	err = skb_cow_head(skb, 0);
617 	if (err)
618 		return err;
619 
620 	if (skb->protocol == cpu_to_be16(ETH_P_IP)) {
621 		inner_ip_hdr(skb)->check = 0;
622 		inner_tcp_hdr(skb)->check =
623 			~csum_tcpudp_magic(inner_ip_hdr(skb)->saddr,
624 					   inner_ip_hdr(skb)->daddr,
625 					   0, IPPROTO_TCP, 0);
626 	} else if (skb->protocol == cpu_to_be16(ETH_P_IPV6)) {
627 		inner_tcp_hdr(skb)->check =
628 			~csum_ipv6_magic(&inner_ipv6_hdr(skb)->saddr,
629 					 &inner_ipv6_hdr(skb)->daddr,
630 					 0, IPPROTO_TCP, 0);
631 	}
632 
633 	return 0;
634 }
635 
636 static int ionic_tx_tcp_pseudo_csum(struct sk_buff *skb)
637 {
638 	int err;
639 
640 	err = skb_cow_head(skb, 0);
641 	if (err)
642 		return err;
643 
644 	if (skb->protocol == cpu_to_be16(ETH_P_IP)) {
645 		ip_hdr(skb)->check = 0;
646 		tcp_hdr(skb)->check =
647 			~csum_tcpudp_magic(ip_hdr(skb)->saddr,
648 					   ip_hdr(skb)->daddr,
649 					   0, IPPROTO_TCP, 0);
650 	} else if (skb->protocol == cpu_to_be16(ETH_P_IPV6)) {
651 		tcp_v6_gso_csum_prep(skb);
652 	}
653 
654 	return 0;
655 }
656 
657 static void ionic_tx_tso_post(struct ionic_queue *q, struct ionic_txq_desc *desc,
658 			      struct sk_buff *skb,
659 			      dma_addr_t addr, u8 nsge, u16 len,
660 			      unsigned int hdrlen, unsigned int mss,
661 			      bool outer_csum,
662 			      u16 vlan_tci, bool has_vlan,
663 			      bool start, bool done)
664 {
665 	u8 flags = 0;
666 	u64 cmd;
667 
668 	flags |= has_vlan ? IONIC_TXQ_DESC_FLAG_VLAN : 0;
669 	flags |= outer_csum ? IONIC_TXQ_DESC_FLAG_ENCAP : 0;
670 	flags |= start ? IONIC_TXQ_DESC_FLAG_TSO_SOT : 0;
671 	flags |= done ? IONIC_TXQ_DESC_FLAG_TSO_EOT : 0;
672 
673 	cmd = encode_txq_desc_cmd(IONIC_TXQ_DESC_OPCODE_TSO, flags, nsge, addr);
674 	desc->cmd = cpu_to_le64(cmd);
675 	desc->len = cpu_to_le16(len);
676 	desc->vlan_tci = cpu_to_le16(vlan_tci);
677 	desc->hdr_len = cpu_to_le16(hdrlen);
678 	desc->mss = cpu_to_le16(mss);
679 
680 	if (done) {
681 		skb_tx_timestamp(skb);
682 		netdev_tx_sent_queue(q_to_ndq(q), skb->len);
683 		ionic_txq_post(q, !netdev_xmit_more(), ionic_tx_clean, skb);
684 	} else {
685 		ionic_txq_post(q, false, ionic_tx_clean, NULL);
686 	}
687 }
688 
689 static struct ionic_txq_desc *ionic_tx_tso_next(struct ionic_queue *q,
690 						struct ionic_txq_sg_elem **elem)
691 {
692 	struct ionic_txq_sg_desc *sg_desc = q->head->sg_desc;
693 	struct ionic_txq_desc *desc = q->head->desc;
694 
695 	*elem = sg_desc->elems;
696 	return desc;
697 }
698 
699 static int ionic_tx_tso(struct ionic_queue *q, struct sk_buff *skb)
700 {
701 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
702 	struct ionic_desc_info *abort = q->head;
703 	struct device *dev = q->lif->ionic->dev;
704 	struct ionic_desc_info *rewind = abort;
705 	struct ionic_txq_sg_elem *elem;
706 	struct ionic_txq_desc *desc;
707 	unsigned int frag_left = 0;
708 	unsigned int offset = 0;
709 	unsigned int len_left;
710 	dma_addr_t desc_addr;
711 	unsigned int hdrlen;
712 	unsigned int nfrags;
713 	unsigned int seglen;
714 	u64 total_bytes = 0;
715 	u64 total_pkts = 0;
716 	unsigned int left;
717 	unsigned int len;
718 	unsigned int mss;
719 	skb_frag_t *frag;
720 	bool start, done;
721 	bool outer_csum;
722 	bool has_vlan;
723 	u16 desc_len;
724 	u8 desc_nsge;
725 	u16 vlan_tci;
726 	bool encap;
727 	int err;
728 
729 	mss = skb_shinfo(skb)->gso_size;
730 	nfrags = skb_shinfo(skb)->nr_frags;
731 	len_left = skb->len - skb_headlen(skb);
732 	outer_csum = (skb_shinfo(skb)->gso_type & SKB_GSO_GRE_CSUM) ||
733 		     (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
734 	has_vlan = !!skb_vlan_tag_present(skb);
735 	vlan_tci = skb_vlan_tag_get(skb);
736 	encap = skb->encapsulation;
737 
738 	/* Preload inner-most TCP csum field with IP pseudo hdr
739 	 * calculated with IP length set to zero.  HW will later
740 	 * add in length to each TCP segment resulting from the TSO.
741 	 */
742 
743 	if (encap)
744 		err = ionic_tx_tcp_inner_pseudo_csum(skb);
745 	else
746 		err = ionic_tx_tcp_pseudo_csum(skb);
747 	if (err)
748 		return err;
749 
750 	if (encap)
751 		hdrlen = skb_inner_transport_header(skb) - skb->data +
752 			 inner_tcp_hdrlen(skb);
753 	else
754 		hdrlen = skb_transport_offset(skb) + tcp_hdrlen(skb);
755 
756 	seglen = hdrlen + mss;
757 	left = skb_headlen(skb);
758 
759 	desc = ionic_tx_tso_next(q, &elem);
760 	start = true;
761 
762 	/* Chop skb->data up into desc segments */
763 
764 	while (left > 0) {
765 		len = min(seglen, left);
766 		frag_left = seglen - len;
767 		desc_addr = ionic_tx_map_single(q, skb->data + offset, len);
768 		if (dma_mapping_error(dev, desc_addr))
769 			goto err_out_abort;
770 		desc_len = len;
771 		desc_nsge = 0;
772 		left -= len;
773 		offset += len;
774 		if (nfrags > 0 && frag_left > 0)
775 			continue;
776 		done = (nfrags == 0 && left == 0);
777 		ionic_tx_tso_post(q, desc, skb,
778 				  desc_addr, desc_nsge, desc_len,
779 				  hdrlen, mss,
780 				  outer_csum,
781 				  vlan_tci, has_vlan,
782 				  start, done);
783 		total_pkts++;
784 		total_bytes += start ? len : len + hdrlen;
785 		desc = ionic_tx_tso_next(q, &elem);
786 		start = false;
787 		seglen = mss;
788 	}
789 
790 	/* Chop skb frags into desc segments */
791 
792 	for (frag = skb_shinfo(skb)->frags; len_left; frag++) {
793 		offset = 0;
794 		left = skb_frag_size(frag);
795 		len_left -= left;
796 		nfrags--;
797 		stats->frags++;
798 
799 		while (left > 0) {
800 			if (frag_left > 0) {
801 				len = min(frag_left, left);
802 				frag_left -= len;
803 				elem->addr =
804 				    cpu_to_le64(ionic_tx_map_frag(q, frag,
805 								  offset, len));
806 				if (dma_mapping_error(dev, elem->addr))
807 					goto err_out_abort;
808 				elem->len = cpu_to_le16(len);
809 				elem++;
810 				desc_nsge++;
811 				left -= len;
812 				offset += len;
813 				if (nfrags > 0 && frag_left > 0)
814 					continue;
815 				done = (nfrags == 0 && left == 0);
816 				ionic_tx_tso_post(q, desc, skb, desc_addr,
817 						  desc_nsge, desc_len,
818 						  hdrlen, mss, outer_csum,
819 						  vlan_tci, has_vlan,
820 						  start, done);
821 				total_pkts++;
822 				total_bytes += start ? len : len + hdrlen;
823 				desc = ionic_tx_tso_next(q, &elem);
824 				start = false;
825 			} else {
826 				len = min(mss, left);
827 				frag_left = mss - len;
828 				desc_addr = ionic_tx_map_frag(q, frag,
829 							      offset, len);
830 				if (dma_mapping_error(dev, desc_addr))
831 					goto err_out_abort;
832 				desc_len = len;
833 				desc_nsge = 0;
834 				left -= len;
835 				offset += len;
836 				if (nfrags > 0 && frag_left > 0)
837 					continue;
838 				done = (nfrags == 0 && left == 0);
839 				ionic_tx_tso_post(q, desc, skb, desc_addr,
840 						  desc_nsge, desc_len,
841 						  hdrlen, mss, outer_csum,
842 						  vlan_tci, has_vlan,
843 						  start, done);
844 				total_pkts++;
845 				total_bytes += start ? len : len + hdrlen;
846 				desc = ionic_tx_tso_next(q, &elem);
847 				start = false;
848 			}
849 		}
850 	}
851 
852 	stats->pkts += total_pkts;
853 	stats->bytes += total_bytes;
854 	stats->tso++;
855 
856 	return 0;
857 
858 err_out_abort:
859 	while (rewind->desc != q->head->desc) {
860 		ionic_tx_clean(q, rewind, NULL, NULL);
861 		rewind = rewind->next;
862 	}
863 	q->head = abort;
864 
865 	return -ENOMEM;
866 }
867 
868 static int ionic_tx_calc_csum(struct ionic_queue *q, struct sk_buff *skb)
869 {
870 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
871 	struct ionic_txq_desc *desc = q->head->desc;
872 	struct device *dev = q->lif->ionic->dev;
873 	dma_addr_t dma_addr;
874 	bool has_vlan;
875 	u8 flags = 0;
876 	bool encap;
877 	u64 cmd;
878 
879 	has_vlan = !!skb_vlan_tag_present(skb);
880 	encap = skb->encapsulation;
881 
882 	dma_addr = ionic_tx_map_single(q, skb->data, skb_headlen(skb));
883 	if (dma_mapping_error(dev, dma_addr))
884 		return -ENOMEM;
885 
886 	flags |= has_vlan ? IONIC_TXQ_DESC_FLAG_VLAN : 0;
887 	flags |= encap ? IONIC_TXQ_DESC_FLAG_ENCAP : 0;
888 
889 	cmd = encode_txq_desc_cmd(IONIC_TXQ_DESC_OPCODE_CSUM_PARTIAL,
890 				  flags, skb_shinfo(skb)->nr_frags, dma_addr);
891 	desc->cmd = cpu_to_le64(cmd);
892 	desc->len = cpu_to_le16(skb_headlen(skb));
893 	desc->vlan_tci = cpu_to_le16(skb_vlan_tag_get(skb));
894 	desc->csum_start = cpu_to_le16(skb_checksum_start_offset(skb));
895 	desc->csum_offset = cpu_to_le16(skb->csum_offset);
896 
897 	if (skb->csum_not_inet)
898 		stats->crc32_csum++;
899 	else
900 		stats->csum++;
901 
902 	return 0;
903 }
904 
905 static int ionic_tx_calc_no_csum(struct ionic_queue *q, struct sk_buff *skb)
906 {
907 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
908 	struct ionic_txq_desc *desc = q->head->desc;
909 	struct device *dev = q->lif->ionic->dev;
910 	dma_addr_t dma_addr;
911 	bool has_vlan;
912 	u8 flags = 0;
913 	bool encap;
914 	u64 cmd;
915 
916 	has_vlan = !!skb_vlan_tag_present(skb);
917 	encap = skb->encapsulation;
918 
919 	dma_addr = ionic_tx_map_single(q, skb->data, skb_headlen(skb));
920 	if (dma_mapping_error(dev, dma_addr))
921 		return -ENOMEM;
922 
923 	flags |= has_vlan ? IONIC_TXQ_DESC_FLAG_VLAN : 0;
924 	flags |= encap ? IONIC_TXQ_DESC_FLAG_ENCAP : 0;
925 
926 	cmd = encode_txq_desc_cmd(IONIC_TXQ_DESC_OPCODE_CSUM_NONE,
927 				  flags, skb_shinfo(skb)->nr_frags, dma_addr);
928 	desc->cmd = cpu_to_le64(cmd);
929 	desc->len = cpu_to_le16(skb_headlen(skb));
930 	desc->vlan_tci = cpu_to_le16(skb_vlan_tag_get(skb));
931 
932 	stats->no_csum++;
933 
934 	return 0;
935 }
936 
937 static int ionic_tx_skb_frags(struct ionic_queue *q, struct sk_buff *skb)
938 {
939 	struct ionic_txq_sg_desc *sg_desc = q->head->sg_desc;
940 	unsigned int len_left = skb->len - skb_headlen(skb);
941 	struct ionic_txq_sg_elem *elem = sg_desc->elems;
942 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
943 	struct device *dev = q->lif->ionic->dev;
944 	dma_addr_t dma_addr;
945 	skb_frag_t *frag;
946 	u16 len;
947 
948 	for (frag = skb_shinfo(skb)->frags; len_left; frag++, elem++) {
949 		len = skb_frag_size(frag);
950 		elem->len = cpu_to_le16(len);
951 		dma_addr = ionic_tx_map_frag(q, frag, 0, len);
952 		if (dma_mapping_error(dev, dma_addr))
953 			return -ENOMEM;
954 		elem->addr = cpu_to_le64(dma_addr);
955 		len_left -= len;
956 		stats->frags++;
957 	}
958 
959 	return 0;
960 }
961 
962 static int ionic_tx(struct ionic_queue *q, struct sk_buff *skb)
963 {
964 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
965 	int err;
966 
967 	/* set up the initial descriptor */
968 	if (skb->ip_summed == CHECKSUM_PARTIAL)
969 		err = ionic_tx_calc_csum(q, skb);
970 	else
971 		err = ionic_tx_calc_no_csum(q, skb);
972 	if (err)
973 		return err;
974 
975 	/* add frags */
976 	err = ionic_tx_skb_frags(q, skb);
977 	if (err)
978 		return err;
979 
980 	skb_tx_timestamp(skb);
981 	stats->pkts++;
982 	stats->bytes += skb->len;
983 
984 	netdev_tx_sent_queue(q_to_ndq(q), skb->len);
985 	ionic_txq_post(q, !netdev_xmit_more(), ionic_tx_clean, skb);
986 
987 	return 0;
988 }
989 
990 static int ionic_tx_descs_needed(struct ionic_queue *q, struct sk_buff *skb)
991 {
992 	struct ionic_tx_stats *stats = q_to_tx_stats(q);
993 	int err;
994 
995 	/* If TSO, need roundup(skb->len/mss) descs */
996 	if (skb_is_gso(skb))
997 		return (skb->len / skb_shinfo(skb)->gso_size) + 1;
998 
999 	/* If non-TSO, just need 1 desc and nr_frags sg elems */
1000 	if (skb_shinfo(skb)->nr_frags <= IONIC_TX_MAX_SG_ELEMS)
1001 		return 1;
1002 
1003 	/* Too many frags, so linearize */
1004 	err = skb_linearize(skb);
1005 	if (err)
1006 		return err;
1007 
1008 	stats->linearize++;
1009 
1010 	/* Need 1 desc and zero sg elems */
1011 	return 1;
1012 }
1013 
1014 static int ionic_maybe_stop_tx(struct ionic_queue *q, int ndescs)
1015 {
1016 	int stopped = 0;
1017 
1018 	if (unlikely(!ionic_q_has_space(q, ndescs))) {
1019 		netif_stop_subqueue(q->lif->netdev, q->index);
1020 		q->stop++;
1021 		stopped = 1;
1022 
1023 		/* Might race with ionic_tx_clean, check again */
1024 		smp_rmb();
1025 		if (ionic_q_has_space(q, ndescs)) {
1026 			netif_wake_subqueue(q->lif->netdev, q->index);
1027 			stopped = 0;
1028 		}
1029 	}
1030 
1031 	return stopped;
1032 }
1033 
1034 netdev_tx_t ionic_start_xmit(struct sk_buff *skb, struct net_device *netdev)
1035 {
1036 	u16 queue_index = skb_get_queue_mapping(skb);
1037 	struct ionic_lif *lif = netdev_priv(netdev);
1038 	struct ionic_queue *q;
1039 	int ndescs;
1040 	int err;
1041 
1042 	if (unlikely(!test_bit(IONIC_LIF_F_UP, lif->state))) {
1043 		dev_kfree_skb(skb);
1044 		return NETDEV_TX_OK;
1045 	}
1046 
1047 	if (unlikely(!lif_to_txqcq(lif, queue_index)))
1048 		queue_index = 0;
1049 	q = lif_to_txq(lif, queue_index);
1050 
1051 	ndescs = ionic_tx_descs_needed(q, skb);
1052 	if (ndescs < 0)
1053 		goto err_out_drop;
1054 
1055 	if (unlikely(ionic_maybe_stop_tx(q, ndescs)))
1056 		return NETDEV_TX_BUSY;
1057 
1058 	if (skb_is_gso(skb))
1059 		err = ionic_tx_tso(q, skb);
1060 	else
1061 		err = ionic_tx(q, skb);
1062 
1063 	if (err)
1064 		goto err_out_drop;
1065 
1066 	/* Stop the queue if there aren't descriptors for the next packet.
1067 	 * Since our SG lists per descriptor take care of most of the possible
1068 	 * fragmentation, we don't need to have many descriptors available.
1069 	 */
1070 	ionic_maybe_stop_tx(q, 4);
1071 
1072 	return NETDEV_TX_OK;
1073 
1074 err_out_drop:
1075 	q->stop++;
1076 	q->drop++;
1077 	dev_kfree_skb(skb);
1078 	return NETDEV_TX_OK;
1079 }
1080