xref: /dpdk/drivers/net/enic/enic_rxtx.c (revision 68a03efeed657e6e05f281479b33b51102797e15)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright 2008-2017 Cisco Systems, Inc.  All rights reserved.
3  * Copyright 2007 Nuova Systems, Inc.  All rights reserved.
4  */
5 
6 #include <rte_mbuf.h>
7 #include <ethdev_driver.h>
8 #include <rte_net.h>
9 #include <rte_prefetch.h>
10 
11 #include "enic_compat.h"
12 #include "rq_enet_desc.h"
13 #include "enic.h"
14 #include "enic_rxtx_common.h"
15 #include <rte_ether.h>
16 #include <rte_ip.h>
17 #include <rte_tcp.h>
18 
19 #define RTE_PMD_USE_PREFETCH
20 
21 #ifdef RTE_PMD_USE_PREFETCH
22 /*Prefetch a cache line into all cache levels. */
23 #define rte_enic_prefetch(p) rte_prefetch0(p)
24 #else
25 #define rte_enic_prefetch(p) do {} while (0)
26 #endif
27 
28 #ifdef RTE_PMD_PACKET_PREFETCH
29 #define rte_packet_prefetch(p) rte_prefetch1(p)
30 #else
31 #define rte_packet_prefetch(p) do {} while (0)
32 #endif
33 
34 /* dummy receive function to replace actual function in
35  * order to do safe reconfiguration operations.
36  */
37 uint16_t
38 enic_dummy_recv_pkts(__rte_unused void *rx_queue,
39 		     __rte_unused struct rte_mbuf **rx_pkts,
40 		     __rte_unused uint16_t nb_pkts)
41 {
42 	return 0;
43 }
44 
45 static inline uint16_t
46 enic_recv_pkts_common(void *rx_queue, struct rte_mbuf **rx_pkts,
47 		      uint16_t nb_pkts, const bool use_64b_desc)
48 {
49 	struct vnic_rq *sop_rq = rx_queue;
50 	struct vnic_rq *data_rq;
51 	struct vnic_rq *rq;
52 	struct enic *enic = vnic_dev_priv(sop_rq->vdev);
53 	uint16_t cq_idx;
54 	uint16_t rq_idx, max_rx;
55 	uint16_t rq_num;
56 	struct rte_mbuf *nmb, *rxmb;
57 	uint16_t nb_rx = 0;
58 	struct vnic_cq *cq;
59 	volatile struct cq_desc *cqd_ptr;
60 	uint8_t color;
61 	uint8_t tnl;
62 	uint16_t seg_length;
63 	struct rte_mbuf *first_seg = sop_rq->pkt_first_seg;
64 	struct rte_mbuf *last_seg = sop_rq->pkt_last_seg;
65 	const int desc_size = use_64b_desc ?
66 		sizeof(struct cq_enet_rq_desc_64) :
67 		sizeof(struct cq_enet_rq_desc);
68 	RTE_BUILD_BUG_ON(sizeof(struct cq_enet_rq_desc_64) != 64);
69 
70 	cq = &enic->cq[enic_cq_rq(enic, sop_rq->index)];
71 	cq_idx = cq->to_clean;		/* index of cqd, rqd, mbuf_table */
72 	cqd_ptr = (struct cq_desc *)((uintptr_t)(cq->ring.descs) +
73 				     cq_idx * desc_size);
74 	color = cq->last_color;
75 
76 	data_rq = &enic->rq[sop_rq->data_queue_idx];
77 
78 	/* Receive until the end of the ring, at most. */
79 	max_rx = RTE_MIN(nb_pkts, cq->ring.desc_count - cq_idx);
80 
81 	while (max_rx) {
82 		volatile struct rq_enet_desc *rqd_ptr;
83 		struct cq_desc cqd;
84 		uint8_t packet_error;
85 		uint16_t ciflags;
86 		uint8_t tc;
87 
88 		max_rx--;
89 
90 		tc = *(volatile uint8_t *)((uintptr_t)cqd_ptr + desc_size - 1);
91 		/* Check for pkts available */
92 		if ((tc & CQ_DESC_COLOR_MASK_NOSHIFT) == color)
93 			break;
94 
95 		/* Get the cq descriptor and extract rq info from it */
96 		cqd = *cqd_ptr;
97 		/*
98 		 * The first 16B of 64B descriptor is identical to the
99 		 * 16B descriptor, except type_color. Copy type_color
100 		 * from the 64B descriptor into the 16B descriptor's
101 		 * field, so the code below can assume the 16B
102 		 * descriptor format.
103 		 */
104 		if (use_64b_desc)
105 			cqd.type_color = tc;
106 		rq_num = cqd.q_number & CQ_DESC_Q_NUM_MASK;
107 		rq_idx = cqd.completed_index & CQ_DESC_COMP_NDX_MASK;
108 
109 		rq = &enic->rq[rq_num];
110 		rqd_ptr = ((struct rq_enet_desc *)rq->ring.descs) + rq_idx;
111 
112 		/* allocate a new mbuf */
113 		nmb = rte_mbuf_raw_alloc(rq->mp);
114 		if (nmb == NULL) {
115 			rte_atomic64_inc(&enic->soft_stats.rx_nombuf);
116 			break;
117 		}
118 
119 		/* A packet error means descriptor and data are untrusted */
120 		packet_error = enic_cq_rx_check_err(&cqd);
121 
122 		/* Get the mbuf to return and replace with one just allocated */
123 		rxmb = rq->mbuf_ring[rq_idx];
124 		rq->mbuf_ring[rq_idx] = nmb;
125 		cq_idx++;
126 
127 		/* Prefetch next mbuf & desc while processing current one */
128 		cqd_ptr = (struct cq_desc *)((uintptr_t)(cq->ring.descs) +
129 					     cq_idx * desc_size);
130 		rte_enic_prefetch(cqd_ptr);
131 
132 		ciflags = enic_cq_rx_desc_ciflags(
133 			(struct cq_enet_rq_desc *)&cqd);
134 
135 		/* Push descriptor for newly allocated mbuf */
136 		nmb->data_off = RTE_PKTMBUF_HEADROOM;
137 		/*
138 		 * Only the address needs to be refilled. length_type of the
139 		 * descriptor it set during initialization
140 		 * (enic_alloc_rx_queue_mbufs) and does not change.
141 		 */
142 		rqd_ptr->address = rte_cpu_to_le_64(nmb->buf_iova +
143 						    RTE_PKTMBUF_HEADROOM);
144 
145 		/* Fill in the rest of the mbuf */
146 		seg_length = enic_cq_rx_desc_n_bytes(&cqd);
147 
148 		if (rq->is_sop) {
149 			first_seg = rxmb;
150 			first_seg->pkt_len = seg_length;
151 		} else {
152 			first_seg->pkt_len = (uint16_t)(first_seg->pkt_len
153 							+ seg_length);
154 			first_seg->nb_segs++;
155 			last_seg->next = rxmb;
156 		}
157 
158 		rxmb->port = enic->port_id;
159 		rxmb->data_len = seg_length;
160 
161 		rq->rx_nb_hold++;
162 
163 		if (!(enic_cq_rx_desc_eop(ciflags))) {
164 			last_seg = rxmb;
165 			continue;
166 		}
167 
168 		/*
169 		 * When overlay offload is enabled, CQ.fcoe indicates the
170 		 * packet is tunnelled.
171 		 */
172 		tnl = enic->overlay_offload &&
173 			(ciflags & CQ_ENET_RQ_DESC_FLAGS_FCOE) != 0;
174 		/* cq rx flags are only valid if eop bit is set */
175 		first_seg->packet_type =
176 			enic_cq_rx_flags_to_pkt_type(&cqd, tnl);
177 		enic_cq_rx_to_pkt_flags(&cqd, first_seg);
178 
179 		/* Wipe the outer types set by enic_cq_rx_flags_to_pkt_type() */
180 		if (tnl) {
181 			first_seg->packet_type &= ~(RTE_PTYPE_L3_MASK |
182 						    RTE_PTYPE_L4_MASK);
183 		}
184 		if (unlikely(packet_error)) {
185 			rte_pktmbuf_free(first_seg);
186 			rte_atomic64_inc(&enic->soft_stats.rx_packet_errors);
187 			continue;
188 		}
189 
190 
191 		/* prefetch mbuf data for caller */
192 		rte_packet_prefetch(RTE_PTR_ADD(first_seg->buf_addr,
193 				    RTE_PKTMBUF_HEADROOM));
194 
195 		/* store the mbuf address into the next entry of the array */
196 		rx_pkts[nb_rx++] = first_seg;
197 	}
198 	if (unlikely(cq_idx == cq->ring.desc_count)) {
199 		cq_idx = 0;
200 		cq->last_color ^= CQ_DESC_COLOR_MASK_NOSHIFT;
201 	}
202 
203 	sop_rq->pkt_first_seg = first_seg;
204 	sop_rq->pkt_last_seg = last_seg;
205 
206 	cq->to_clean = cq_idx;
207 
208 	if ((sop_rq->rx_nb_hold + data_rq->rx_nb_hold) >
209 	    sop_rq->rx_free_thresh) {
210 		if (data_rq->in_use) {
211 			data_rq->posted_index =
212 				enic_ring_add(data_rq->ring.desc_count,
213 					      data_rq->posted_index,
214 					      data_rq->rx_nb_hold);
215 			data_rq->rx_nb_hold = 0;
216 		}
217 		sop_rq->posted_index = enic_ring_add(sop_rq->ring.desc_count,
218 						     sop_rq->posted_index,
219 						     sop_rq->rx_nb_hold);
220 		sop_rq->rx_nb_hold = 0;
221 
222 		rte_mb();
223 		if (data_rq->in_use)
224 			iowrite32_relaxed(data_rq->posted_index,
225 					  &data_rq->ctrl->posted_index);
226 		rte_compiler_barrier();
227 		iowrite32_relaxed(sop_rq->posted_index,
228 				  &sop_rq->ctrl->posted_index);
229 	}
230 
231 
232 	return nb_rx;
233 }
234 
235 uint16_t
236 enic_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
237 {
238 	return enic_recv_pkts_common(rx_queue, rx_pkts, nb_pkts, false);
239 }
240 
241 uint16_t
242 enic_recv_pkts_64(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
243 {
244 	return enic_recv_pkts_common(rx_queue, rx_pkts, nb_pkts, true);
245 }
246 
247 uint16_t
248 enic_noscatter_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts,
249 			 uint16_t nb_pkts)
250 {
251 	struct rte_mbuf *mb, **rx, **rxmb;
252 	uint16_t cq_idx, nb_rx, max_rx;
253 	struct cq_enet_rq_desc *cqd;
254 	struct rq_enet_desc *rqd;
255 	unsigned int port_id;
256 	struct vnic_cq *cq;
257 	struct vnic_rq *rq;
258 	struct enic *enic;
259 	uint8_t color;
260 	bool overlay;
261 	bool tnl;
262 
263 	rq = rx_queue;
264 	enic = vnic_dev_priv(rq->vdev);
265 	cq = &enic->cq[enic_cq_rq(enic, rq->index)];
266 	cq_idx = cq->to_clean;
267 
268 	/*
269 	 * Fill up the reserve of free mbufs. Below, we restock the receive
270 	 * ring with these mbufs to avoid allocation failures.
271 	 */
272 	if (rq->num_free_mbufs == 0) {
273 		if (rte_mempool_get_bulk(rq->mp, (void **)rq->free_mbufs,
274 					 ENIC_RX_BURST_MAX))
275 			return 0;
276 		rq->num_free_mbufs = ENIC_RX_BURST_MAX;
277 	}
278 
279 	/* Receive until the end of the ring, at most. */
280 	max_rx = RTE_MIN(nb_pkts, rq->num_free_mbufs);
281 	max_rx = RTE_MIN(max_rx, cq->ring.desc_count - cq_idx);
282 
283 	cqd = (struct cq_enet_rq_desc *)(cq->ring.descs) + cq_idx;
284 	color = cq->last_color;
285 	rxmb = rq->mbuf_ring + cq_idx;
286 	port_id = enic->port_id;
287 	overlay = enic->overlay_offload;
288 
289 	rx = rx_pkts;
290 	while (max_rx) {
291 		max_rx--;
292 		if ((cqd->type_color & CQ_DESC_COLOR_MASK_NOSHIFT) == color)
293 			break;
294 		if (unlikely(cqd->bytes_written_flags &
295 			     CQ_ENET_RQ_DESC_FLAGS_TRUNCATED)) {
296 			rte_pktmbuf_free(*rxmb++);
297 			rte_atomic64_inc(&enic->soft_stats.rx_packet_errors);
298 			cqd++;
299 			continue;
300 		}
301 
302 		mb = *rxmb++;
303 		/* prefetch mbuf data for caller */
304 		rte_packet_prefetch(RTE_PTR_ADD(mb->buf_addr,
305 				    RTE_PKTMBUF_HEADROOM));
306 		mb->data_len = cqd->bytes_written_flags &
307 			CQ_ENET_RQ_DESC_BYTES_WRITTEN_MASK;
308 		mb->pkt_len = mb->data_len;
309 		mb->port = port_id;
310 		tnl = overlay && (cqd->completed_index_flags &
311 				  CQ_ENET_RQ_DESC_FLAGS_FCOE) != 0;
312 		mb->packet_type =
313 			enic_cq_rx_flags_to_pkt_type((struct cq_desc *)cqd,
314 						     tnl);
315 		enic_cq_rx_to_pkt_flags((struct cq_desc *)cqd, mb);
316 		/* Wipe the outer types set by enic_cq_rx_flags_to_pkt_type() */
317 		if (tnl) {
318 			mb->packet_type &= ~(RTE_PTYPE_L3_MASK |
319 					     RTE_PTYPE_L4_MASK);
320 		}
321 		cqd++;
322 		*rx++ = mb;
323 	}
324 	/* Number of descriptors visited */
325 	nb_rx = cqd - (struct cq_enet_rq_desc *)(cq->ring.descs) - cq_idx;
326 	if (nb_rx == 0)
327 		return 0;
328 	rqd = ((struct rq_enet_desc *)rq->ring.descs) + cq_idx;
329 	rxmb = rq->mbuf_ring + cq_idx;
330 	cq_idx += nb_rx;
331 	rq->rx_nb_hold += nb_rx;
332 	if (unlikely(cq_idx == cq->ring.desc_count)) {
333 		cq_idx = 0;
334 		cq->last_color ^= CQ_DESC_COLOR_MASK_NOSHIFT;
335 	}
336 	cq->to_clean = cq_idx;
337 
338 	memcpy(rxmb, rq->free_mbufs + ENIC_RX_BURST_MAX - rq->num_free_mbufs,
339 	       sizeof(struct rte_mbuf *) * nb_rx);
340 	rq->num_free_mbufs -= nb_rx;
341 	while (nb_rx) {
342 		nb_rx--;
343 		mb = *rxmb++;
344 		mb->data_off = RTE_PKTMBUF_HEADROOM;
345 		rqd->address = mb->buf_iova + RTE_PKTMBUF_HEADROOM;
346 		rqd++;
347 	}
348 	if (rq->rx_nb_hold > rq->rx_free_thresh) {
349 		rq->posted_index = enic_ring_add(rq->ring.desc_count,
350 						 rq->posted_index,
351 						 rq->rx_nb_hold);
352 		rq->rx_nb_hold = 0;
353 		rte_wmb();
354 		iowrite32_relaxed(rq->posted_index,
355 				  &rq->ctrl->posted_index);
356 	}
357 
358 	return rx - rx_pkts;
359 }
360 
361 static inline void enic_free_wq_bufs(struct vnic_wq *wq,
362 				     uint16_t completed_index)
363 {
364 	struct rte_mbuf *buf;
365 	struct rte_mbuf *m, *free[ENIC_MAX_WQ_DESCS];
366 	unsigned int nb_to_free, nb_free = 0, i;
367 	struct rte_mempool *pool;
368 	unsigned int tail_idx;
369 	unsigned int desc_count = wq->ring.desc_count;
370 
371 	nb_to_free = enic_ring_sub(desc_count, wq->tail_idx, completed_index)
372 				   + 1;
373 	tail_idx = wq->tail_idx;
374 	pool = wq->bufs[tail_idx]->pool;
375 	for (i = 0; i < nb_to_free; i++) {
376 		buf = wq->bufs[tail_idx];
377 		m = rte_pktmbuf_prefree_seg(buf);
378 		if (unlikely(m == NULL)) {
379 			tail_idx = enic_ring_incr(desc_count, tail_idx);
380 			continue;
381 		}
382 
383 		if (likely(m->pool == pool)) {
384 			RTE_ASSERT(nb_free < ENIC_MAX_WQ_DESCS);
385 			free[nb_free++] = m;
386 		} else {
387 			rte_mempool_put_bulk(pool, (void *)free, nb_free);
388 			free[0] = m;
389 			nb_free = 1;
390 			pool = m->pool;
391 		}
392 		tail_idx = enic_ring_incr(desc_count, tail_idx);
393 	}
394 
395 	if (nb_free > 0)
396 		rte_mempool_put_bulk(pool, (void **)free, nb_free);
397 
398 	wq->tail_idx = tail_idx;
399 	wq->ring.desc_avail += nb_to_free;
400 }
401 
402 unsigned int enic_cleanup_wq(__rte_unused struct enic *enic, struct vnic_wq *wq)
403 {
404 	uint16_t completed_index;
405 
406 	completed_index = *((uint32_t *)wq->cqmsg_rz->addr) & 0xffff;
407 
408 	if (wq->last_completed_index != completed_index) {
409 		enic_free_wq_bufs(wq, completed_index);
410 		wq->last_completed_index = completed_index;
411 	}
412 	return 0;
413 }
414 
415 uint16_t enic_prep_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
416 			uint16_t nb_pkts)
417 {
418 	struct vnic_wq *wq = (struct vnic_wq *)tx_queue;
419 	int32_t ret;
420 	uint16_t i;
421 	uint64_t ol_flags;
422 	struct rte_mbuf *m;
423 
424 	for (i = 0; i != nb_pkts; i++) {
425 		m = tx_pkts[i];
426 		ol_flags = m->ol_flags;
427 		if (!(ol_flags & PKT_TX_TCP_SEG)) {
428 			if (unlikely(m->pkt_len > ENIC_TX_MAX_PKT_SIZE)) {
429 				rte_errno = EINVAL;
430 				return i;
431 			}
432 		} else {
433 			uint16_t header_len;
434 
435 			header_len = m->l2_len + m->l3_len + m->l4_len;
436 			if (m->tso_segsz + header_len > ENIC_TX_MAX_PKT_SIZE) {
437 				rte_errno = EINVAL;
438 				return i;
439 			}
440 		}
441 
442 		if (ol_flags & wq->tx_offload_notsup_mask) {
443 			rte_errno = ENOTSUP;
444 			return i;
445 		}
446 #ifdef RTE_LIBRTE_ETHDEV_DEBUG
447 		ret = rte_validate_tx_offload(m);
448 		if (ret != 0) {
449 			rte_errno = -ret;
450 			return i;
451 		}
452 #endif
453 		ret = rte_net_intel_cksum_prepare(m);
454 		if (ret != 0) {
455 			rte_errno = -ret;
456 			return i;
457 		}
458 	}
459 
460 	return i;
461 }
462 
463 uint16_t enic_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
464 	uint16_t nb_pkts)
465 {
466 	uint16_t index;
467 	unsigned int pkt_len, data_len;
468 	unsigned int nb_segs;
469 	struct rte_mbuf *tx_pkt;
470 	struct vnic_wq *wq = (struct vnic_wq *)tx_queue;
471 	struct enic *enic = vnic_dev_priv(wq->vdev);
472 	unsigned short vlan_id;
473 	uint64_t ol_flags;
474 	uint64_t ol_flags_mask;
475 	unsigned int wq_desc_avail;
476 	int head_idx;
477 	unsigned int desc_count;
478 	struct wq_enet_desc *descs, *desc_p, desc_tmp;
479 	uint16_t mss;
480 	uint8_t vlan_tag_insert;
481 	uint8_t eop, cq;
482 	uint64_t bus_addr;
483 	uint8_t offload_mode;
484 	uint16_t header_len;
485 	uint64_t tso;
486 	rte_atomic64_t *tx_oversized;
487 
488 	enic_cleanup_wq(enic, wq);
489 	wq_desc_avail = vnic_wq_desc_avail(wq);
490 	head_idx = wq->head_idx;
491 	desc_count = wq->ring.desc_count;
492 	ol_flags_mask = PKT_TX_VLAN | PKT_TX_IP_CKSUM | PKT_TX_L4_MASK;
493 	tx_oversized = &enic->soft_stats.tx_oversized;
494 
495 	nb_pkts = RTE_MIN(nb_pkts, ENIC_TX_XMIT_MAX);
496 
497 	for (index = 0; index < nb_pkts; index++) {
498 		tx_pkt = *tx_pkts++;
499 		pkt_len = tx_pkt->pkt_len;
500 		data_len = tx_pkt->data_len;
501 		ol_flags = tx_pkt->ol_flags;
502 		nb_segs = tx_pkt->nb_segs;
503 		tso = ol_flags & PKT_TX_TCP_SEG;
504 
505 		/* drop packet if it's too big to send */
506 		if (unlikely(!tso && pkt_len > ENIC_TX_MAX_PKT_SIZE)) {
507 			rte_pktmbuf_free(tx_pkt);
508 			rte_atomic64_inc(tx_oversized);
509 			continue;
510 		}
511 
512 		if (nb_segs > wq_desc_avail) {
513 			if (index > 0)
514 				goto post;
515 			goto done;
516 		}
517 
518 		mss = 0;
519 		vlan_id = tx_pkt->vlan_tci;
520 		vlan_tag_insert = !!(ol_flags & PKT_TX_VLAN);
521 		bus_addr = (dma_addr_t)
522 			   (tx_pkt->buf_iova + tx_pkt->data_off);
523 
524 		descs = (struct wq_enet_desc *)wq->ring.descs;
525 		desc_p = descs + head_idx;
526 
527 		eop = (data_len == pkt_len);
528 		offload_mode = WQ_ENET_OFFLOAD_MODE_CSUM;
529 		header_len = 0;
530 
531 		if (tso) {
532 			header_len = tx_pkt->l2_len + tx_pkt->l3_len +
533 				     tx_pkt->l4_len;
534 
535 			/* Drop if non-TCP packet or TSO seg size is too big */
536 			if (unlikely(header_len == 0 || ((tx_pkt->tso_segsz +
537 			    header_len) > ENIC_TX_MAX_PKT_SIZE))) {
538 				rte_pktmbuf_free(tx_pkt);
539 				rte_atomic64_inc(tx_oversized);
540 				continue;
541 			}
542 
543 			offload_mode = WQ_ENET_OFFLOAD_MODE_TSO;
544 			mss = tx_pkt->tso_segsz;
545 			/* For tunnel, need the size of outer+inner headers */
546 			if (ol_flags & PKT_TX_TUNNEL_MASK) {
547 				header_len += tx_pkt->outer_l2_len +
548 					tx_pkt->outer_l3_len;
549 			}
550 		}
551 
552 		if ((ol_flags & ol_flags_mask) && (header_len == 0)) {
553 			if (ol_flags & PKT_TX_IP_CKSUM)
554 				mss |= ENIC_CALC_IP_CKSUM;
555 
556 			/* Nic uses just 1 bit for UDP and TCP */
557 			switch (ol_flags & PKT_TX_L4_MASK) {
558 			case PKT_TX_TCP_CKSUM:
559 			case PKT_TX_UDP_CKSUM:
560 				mss |= ENIC_CALC_TCP_UDP_CKSUM;
561 				break;
562 			}
563 		}
564 		wq->cq_pend++;
565 		cq = 0;
566 		if (eop && wq->cq_pend >= ENIC_WQ_CQ_THRESH) {
567 			cq = 1;
568 			wq->cq_pend = 0;
569 		}
570 		wq_enet_desc_enc(&desc_tmp, bus_addr, data_len, mss, header_len,
571 				 offload_mode, eop, cq, 0, vlan_tag_insert,
572 				 vlan_id, 0);
573 
574 		*desc_p = desc_tmp;
575 		wq->bufs[head_idx] = tx_pkt;
576 		head_idx = enic_ring_incr(desc_count, head_idx);
577 		wq_desc_avail--;
578 
579 		if (!eop) {
580 			for (tx_pkt = tx_pkt->next; tx_pkt; tx_pkt =
581 			    tx_pkt->next) {
582 				data_len = tx_pkt->data_len;
583 
584 				wq->cq_pend++;
585 				cq = 0;
586 				if (tx_pkt->next == NULL) {
587 					eop = 1;
588 					if (wq->cq_pend >= ENIC_WQ_CQ_THRESH) {
589 						cq = 1;
590 						wq->cq_pend = 0;
591 					}
592 				}
593 				desc_p = descs + head_idx;
594 				bus_addr = (dma_addr_t)(tx_pkt->buf_iova
595 					   + tx_pkt->data_off);
596 				wq_enet_desc_enc((struct wq_enet_desc *)
597 						 &desc_tmp, bus_addr, data_len,
598 						 mss, 0, offload_mode, eop, cq,
599 						 0, vlan_tag_insert, vlan_id,
600 						 0);
601 
602 				*desc_p = desc_tmp;
603 				wq->bufs[head_idx] = tx_pkt;
604 				head_idx = enic_ring_incr(desc_count, head_idx);
605 				wq_desc_avail--;
606 			}
607 		}
608 	}
609  post:
610 	rte_wmb();
611 	iowrite32_relaxed(head_idx, &wq->ctrl->posted_index);
612  done:
613 	wq->ring.desc_avail = wq_desc_avail;
614 	wq->head_idx = head_idx;
615 
616 	return index;
617 }
618 
619 static void enqueue_simple_pkts(struct rte_mbuf **pkts,
620 				struct wq_enet_desc *desc,
621 				uint16_t n,
622 				struct enic *enic)
623 {
624 	struct rte_mbuf *p;
625 	uint16_t mss;
626 
627 	while (n) {
628 		n--;
629 		p = *pkts++;
630 		desc->address = p->buf_iova + p->data_off;
631 		desc->length = p->pkt_len;
632 		/* VLAN insert */
633 		desc->vlan_tag = p->vlan_tci;
634 		desc->header_length_flags &=
635 			((1 << WQ_ENET_FLAGS_EOP_SHIFT) |
636 			 (1 << WQ_ENET_FLAGS_CQ_ENTRY_SHIFT));
637 		if (p->ol_flags & PKT_TX_VLAN) {
638 			desc->header_length_flags |=
639 				1 << WQ_ENET_FLAGS_VLAN_TAG_INSERT_SHIFT;
640 		}
641 		/*
642 		 * Checksum offload. We use WQ_ENET_OFFLOAD_MODE_CSUM, which
643 		 * is 0, so no need to set offload_mode.
644 		 */
645 		mss = 0;
646 		if (p->ol_flags & PKT_TX_IP_CKSUM)
647 			mss |= ENIC_CALC_IP_CKSUM << WQ_ENET_MSS_SHIFT;
648 		if (p->ol_flags & PKT_TX_L4_MASK)
649 			mss |= ENIC_CALC_TCP_UDP_CKSUM << WQ_ENET_MSS_SHIFT;
650 		desc->mss_loopback = mss;
651 
652 		/*
653 		 * The app should not send oversized
654 		 * packets. tx_pkt_prepare includes a check as
655 		 * well. But some apps ignore the device max size and
656 		 * tx_pkt_prepare. Oversized packets cause WQ errrors
657 		 * and the NIC ends up disabling the whole WQ. So
658 		 * truncate packets..
659 		 */
660 		if (unlikely(p->pkt_len > ENIC_TX_MAX_PKT_SIZE)) {
661 			desc->length = ENIC_TX_MAX_PKT_SIZE;
662 			rte_atomic64_inc(&enic->soft_stats.tx_oversized);
663 		}
664 		desc++;
665 	}
666 }
667 
668 uint16_t enic_simple_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
669 			       uint16_t nb_pkts)
670 {
671 	unsigned int head_idx, desc_count;
672 	struct wq_enet_desc *desc;
673 	struct vnic_wq *wq;
674 	struct enic *enic;
675 	uint16_t rem, n;
676 
677 	wq = (struct vnic_wq *)tx_queue;
678 	enic = vnic_dev_priv(wq->vdev);
679 	enic_cleanup_wq(enic, wq);
680 	/* Will enqueue this many packets in this call */
681 	nb_pkts = RTE_MIN(nb_pkts, wq->ring.desc_avail);
682 	if (nb_pkts == 0)
683 		return 0;
684 
685 	head_idx = wq->head_idx;
686 	desc_count = wq->ring.desc_count;
687 
688 	/* Descriptors until the end of the ring */
689 	n = desc_count - head_idx;
690 	n = RTE_MIN(nb_pkts, n);
691 
692 	/* Save mbuf pointers to free later */
693 	memcpy(wq->bufs + head_idx, tx_pkts, sizeof(struct rte_mbuf *) * n);
694 
695 	/* Enqueue until the ring end */
696 	rem = nb_pkts - n;
697 	desc = ((struct wq_enet_desc *)wq->ring.descs) + head_idx;
698 	enqueue_simple_pkts(tx_pkts, desc, n, enic);
699 
700 	/* Wrap to the start of the ring */
701 	if (rem) {
702 		tx_pkts += n;
703 		memcpy(wq->bufs, tx_pkts, sizeof(struct rte_mbuf *) * rem);
704 		desc = (struct wq_enet_desc *)wq->ring.descs;
705 		enqueue_simple_pkts(tx_pkts, desc, rem, enic);
706 	}
707 	rte_wmb();
708 
709 	/* Update head_idx and desc_avail */
710 	wq->ring.desc_avail -= nb_pkts;
711 	head_idx += nb_pkts;
712 	if (head_idx >= desc_count)
713 		head_idx -= desc_count;
714 	wq->head_idx = head_idx;
715 	iowrite32_relaxed(head_idx, &wq->ctrl->posted_index);
716 	return nb_pkts;
717 }
718