Imported Upstream version 16.07-rc4
[deb_dpdk.git] / drivers / net / enic / enic_rxtx.c
1 /* Copyright 2008-2016 Cisco Systems, Inc.  All rights reserved.
2  * Copyright 2007 Nuova Systems, Inc.  All rights reserved.
3  *
4  * Copyright (c) 2014, Cisco Systems, Inc.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  * notice, this list of conditions and the following disclaimer.
13  *
14  * 2. Redistributions in binary form must reproduce the above copyright
15  * notice, this list of conditions and the following disclaimer in
16  * the documentation and/or other materials provided with the
17  * distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
22  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
23  * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
25  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
26  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
27  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
29  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30  * POSSIBILITY OF SUCH DAMAGE.
31  */
32
33 #include <rte_mbuf.h>
34 #include <rte_ethdev.h>
35 #include <rte_prefetch.h>
36
37 #include "enic_compat.h"
38 #include "rq_enet_desc.h"
39 #include "enic.h"
40
41 #define RTE_PMD_USE_PREFETCH
42
43 #ifdef RTE_PMD_USE_PREFETCH
44 /*Prefetch a cache line into all cache levels. */
45 #define rte_enic_prefetch(p) rte_prefetch0(p)
46 #else
47 #define rte_enic_prefetch(p) do {} while (0)
48 #endif
49
50 #ifdef RTE_PMD_PACKET_PREFETCH
51 #define rte_packet_prefetch(p) rte_prefetch1(p)
52 #else
53 #define rte_packet_prefetch(p) do {} while (0)
54 #endif
55
56 static inline uint16_t
57 enic_cq_rx_desc_ciflags(struct cq_enet_rq_desc *crd)
58 {
59         return le16_to_cpu(crd->completed_index_flags) & ~CQ_DESC_COMP_NDX_MASK;
60 }
61
62 static inline uint16_t
63 enic_cq_rx_desc_bwflags(struct cq_enet_rq_desc *crd)
64 {
65         return le16_to_cpu(crd->bytes_written_flags) &
66                            ~CQ_ENET_RQ_DESC_BYTES_WRITTEN_MASK;
67 }
68
69 static inline uint8_t
70 enic_cq_rx_desc_packet_error(uint16_t bwflags)
71 {
72         return (bwflags & CQ_ENET_RQ_DESC_FLAGS_TRUNCATED) ==
73                 CQ_ENET_RQ_DESC_FLAGS_TRUNCATED;
74 }
75
76 static inline uint8_t
77 enic_cq_rx_desc_eop(uint16_t ciflags)
78 {
79         return (ciflags & CQ_ENET_RQ_DESC_FLAGS_EOP)
80                 == CQ_ENET_RQ_DESC_FLAGS_EOP;
81 }
82
83 static inline uint8_t
84 enic_cq_rx_desc_csum_not_calc(struct cq_enet_rq_desc *cqrd)
85 {
86         return (le16_to_cpu(cqrd->q_number_rss_type_flags) &
87                 CQ_ENET_RQ_DESC_FLAGS_CSUM_NOT_CALC) ==
88                 CQ_ENET_RQ_DESC_FLAGS_CSUM_NOT_CALC;
89 }
90
91 static inline uint8_t
92 enic_cq_rx_desc_ipv4_csum_ok(struct cq_enet_rq_desc *cqrd)
93 {
94         return (cqrd->flags & CQ_ENET_RQ_DESC_FLAGS_IPV4_CSUM_OK) ==
95                 CQ_ENET_RQ_DESC_FLAGS_IPV4_CSUM_OK;
96 }
97
98 static inline uint8_t
99 enic_cq_rx_desc_tcp_udp_csum_ok(struct cq_enet_rq_desc *cqrd)
100 {
101         return (cqrd->flags & CQ_ENET_RQ_DESC_FLAGS_TCP_UDP_CSUM_OK) ==
102                 CQ_ENET_RQ_DESC_FLAGS_TCP_UDP_CSUM_OK;
103 }
104
105 static inline uint8_t
106 enic_cq_rx_desc_rss_type(struct cq_enet_rq_desc *cqrd)
107 {
108         return (uint8_t)((le16_to_cpu(cqrd->q_number_rss_type_flags) >>
109                 CQ_DESC_Q_NUM_BITS) & CQ_ENET_RQ_DESC_RSS_TYPE_MASK);
110 }
111
112 static inline uint32_t
113 enic_cq_rx_desc_rss_hash(struct cq_enet_rq_desc *cqrd)
114 {
115         return le32_to_cpu(cqrd->rss_hash);
116 }
117
118 static inline uint16_t
119 enic_cq_rx_desc_vlan(struct cq_enet_rq_desc *cqrd)
120 {
121         return le16_to_cpu(cqrd->vlan);
122 }
123
124 static inline uint16_t
125 enic_cq_rx_desc_n_bytes(struct cq_desc *cqd)
126 {
127         struct cq_enet_rq_desc *cqrd = (struct cq_enet_rq_desc *)cqd;
128         return le16_to_cpu(cqrd->bytes_written_flags) &
129                 CQ_ENET_RQ_DESC_BYTES_WRITTEN_MASK;
130 }
131
132 static inline uint8_t
133 enic_cq_rx_check_err(struct cq_desc *cqd)
134 {
135         struct cq_enet_rq_desc *cqrd = (struct cq_enet_rq_desc *)cqd;
136         uint16_t bwflags;
137
138         bwflags = enic_cq_rx_desc_bwflags(cqrd);
139         if (unlikely(enic_cq_rx_desc_packet_error(bwflags)))
140                 return 1;
141         return 0;
142 }
143
144 /* Lookup table to translate RX CQ flags to mbuf flags. */
145 static inline uint32_t
146 enic_cq_rx_flags_to_pkt_type(struct cq_desc *cqd)
147 {
148         struct cq_enet_rq_desc *cqrd = (struct cq_enet_rq_desc *)cqd;
149         uint8_t cqrd_flags = cqrd->flags;
150         static const uint32_t cq_type_table[128] __rte_cache_aligned = {
151                 [0x00] = RTE_PTYPE_UNKNOWN,
152                 [0x20] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN
153                           | RTE_PTYPE_L4_NONFRAG,
154                 [0x22] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN
155                           | RTE_PTYPE_L4_UDP,
156                 [0x24] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN
157                           | RTE_PTYPE_L4_TCP,
158                 [0x60] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN
159                           | RTE_PTYPE_L4_FRAG,
160                 [0x62] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN
161                           | RTE_PTYPE_L4_UDP,
162                 [0x64] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN
163                           | RTE_PTYPE_L4_TCP,
164                 [0x10] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN
165                           | RTE_PTYPE_L4_NONFRAG,
166                 [0x12] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN
167                           | RTE_PTYPE_L4_UDP,
168                 [0x14] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN
169                           | RTE_PTYPE_L4_TCP,
170                 [0x50] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN
171                           | RTE_PTYPE_L4_FRAG,
172                 [0x52] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN
173                           | RTE_PTYPE_L4_UDP,
174                 [0x54] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN
175                           | RTE_PTYPE_L4_TCP,
176                 /* All others reserved */
177         };
178         cqrd_flags &= CQ_ENET_RQ_DESC_FLAGS_IPV4_FRAGMENT
179                 | CQ_ENET_RQ_DESC_FLAGS_IPV4 | CQ_ENET_RQ_DESC_FLAGS_IPV6
180                 | CQ_ENET_RQ_DESC_FLAGS_TCP | CQ_ENET_RQ_DESC_FLAGS_UDP;
181         return cq_type_table[cqrd_flags];
182 }
183
184 static inline void
185 enic_cq_rx_to_pkt_flags(struct cq_desc *cqd, struct rte_mbuf *mbuf)
186 {
187         struct cq_enet_rq_desc *cqrd = (struct cq_enet_rq_desc *)cqd;
188         uint16_t ciflags, bwflags, pkt_flags = 0;
189         ciflags = enic_cq_rx_desc_ciflags(cqrd);
190         bwflags = enic_cq_rx_desc_bwflags(cqrd);
191
192         mbuf->ol_flags = 0;
193
194         /* flags are meaningless if !EOP */
195         if (unlikely(!enic_cq_rx_desc_eop(ciflags)))
196                 goto mbuf_flags_done;
197
198         /* VLAN stripping */
199         if (bwflags & CQ_ENET_RQ_DESC_FLAGS_VLAN_STRIPPED) {
200                 pkt_flags |= PKT_RX_VLAN_PKT | PKT_RX_VLAN_STRIPPED;
201                 mbuf->vlan_tci = enic_cq_rx_desc_vlan(cqrd);
202         } else {
203                 mbuf->vlan_tci = 0;
204         }
205
206         /* RSS flag */
207         if (enic_cq_rx_desc_rss_type(cqrd)) {
208                 pkt_flags |= PKT_RX_RSS_HASH;
209                 mbuf->hash.rss = enic_cq_rx_desc_rss_hash(cqrd);
210         }
211
212         /* checksum flags */
213         if (!enic_cq_rx_desc_csum_not_calc(cqrd) &&
214                 (mbuf->packet_type & RTE_PTYPE_L3_IPV4)) {
215                 if (unlikely(!enic_cq_rx_desc_ipv4_csum_ok(cqrd)))
216                         pkt_flags |= PKT_RX_IP_CKSUM_BAD;
217                 if (mbuf->packet_type & (RTE_PTYPE_L4_UDP | RTE_PTYPE_L4_TCP)) {
218                         if (unlikely(!enic_cq_rx_desc_tcp_udp_csum_ok(cqrd)))
219                                 pkt_flags |= PKT_RX_L4_CKSUM_BAD;
220                 }
221         }
222
223  mbuf_flags_done:
224         mbuf->ol_flags = pkt_flags;
225 }
226
227 uint16_t
228 enic_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts,
229                uint16_t nb_pkts)
230 {
231         struct vnic_rq *sop_rq = rx_queue;
232         struct vnic_rq *data_rq;
233         struct vnic_rq *rq;
234         struct enic *enic = vnic_dev_priv(sop_rq->vdev);
235         uint16_t cq_idx;
236         uint16_t rq_idx;
237         uint16_t rq_num;
238         struct rte_mbuf *nmb, *rxmb;
239         uint16_t nb_rx = 0;
240         struct vnic_cq *cq;
241         volatile struct cq_desc *cqd_ptr;
242         uint8_t color;
243         uint16_t seg_length;
244         struct rte_mbuf *first_seg = sop_rq->pkt_first_seg;
245         struct rte_mbuf *last_seg = sop_rq->pkt_last_seg;
246
247         cq = &enic->cq[enic_cq_rq(enic, sop_rq->index)];
248         cq_idx = cq->to_clean;          /* index of cqd, rqd, mbuf_table */
249         cqd_ptr = (struct cq_desc *)(cq->ring.descs) + cq_idx;
250
251         data_rq = &enic->rq[sop_rq->data_queue_idx];
252
253         while (nb_rx < nb_pkts) {
254                 volatile struct rq_enet_desc *rqd_ptr;
255                 dma_addr_t dma_addr;
256                 struct cq_desc cqd;
257                 uint8_t packet_error;
258                 uint16_t ciflags;
259
260                 /* Check for pkts available */
261                 color = (cqd_ptr->type_color >> CQ_DESC_COLOR_SHIFT)
262                         & CQ_DESC_COLOR_MASK;
263                 if (color == cq->last_color)
264                         break;
265
266                 /* Get the cq descriptor and extract rq info from it */
267                 cqd = *cqd_ptr;
268                 rq_num = cqd.q_number & CQ_DESC_Q_NUM_MASK;
269                 rq_idx = cqd.completed_index & CQ_DESC_COMP_NDX_MASK;
270
271                 rq = &enic->rq[rq_num];
272                 rqd_ptr = ((struct rq_enet_desc *)rq->ring.descs) + rq_idx;
273
274                 /* allocate a new mbuf */
275                 nmb = rte_mbuf_raw_alloc(rq->mp);
276                 if (nmb == NULL) {
277                         rte_atomic64_inc(&enic->soft_stats.rx_nombuf);
278                         break;
279                 }
280
281                 /* A packet error means descriptor and data are untrusted */
282                 packet_error = enic_cq_rx_check_err(&cqd);
283
284                 /* Get the mbuf to return and replace with one just allocated */
285                 rxmb = rq->mbuf_ring[rq_idx];
286                 rq->mbuf_ring[rq_idx] = nmb;
287
288                 /* Increment cqd, rqd, mbuf_table index */
289                 cq_idx++;
290                 if (unlikely(cq_idx == cq->ring.desc_count)) {
291                         cq_idx = 0;
292                         cq->last_color = cq->last_color ? 0 : 1;
293                 }
294
295                 /* Prefetch next mbuf & desc while processing current one */
296                 cqd_ptr = (struct cq_desc *)(cq->ring.descs) + cq_idx;
297                 rte_enic_prefetch(cqd_ptr);
298
299                 ciflags = enic_cq_rx_desc_ciflags(
300                         (struct cq_enet_rq_desc *)&cqd);
301
302                 /* Push descriptor for newly allocated mbuf */
303                 nmb->data_off = RTE_PKTMBUF_HEADROOM;
304                 dma_addr = (dma_addr_t)(nmb->buf_physaddr +
305                                         RTE_PKTMBUF_HEADROOM);
306                 rq_enet_desc_enc(rqd_ptr, dma_addr,
307                                 (rq->is_sop ? RQ_ENET_TYPE_ONLY_SOP
308                                 : RQ_ENET_TYPE_NOT_SOP),
309                                 nmb->buf_len - RTE_PKTMBUF_HEADROOM);
310
311                 /* Fill in the rest of the mbuf */
312                 seg_length = enic_cq_rx_desc_n_bytes(&cqd);
313
314                 if (rq->is_sop) {
315                         first_seg = rxmb;
316                         first_seg->nb_segs = 1;
317                         first_seg->pkt_len = seg_length;
318                 } else {
319                         first_seg->pkt_len = (uint16_t)(first_seg->pkt_len
320                                                         + seg_length);
321                         first_seg->nb_segs++;
322                         last_seg->next = rxmb;
323                 }
324
325                 rxmb->next = NULL;
326                 rxmb->port = enic->port_id;
327                 rxmb->data_len = seg_length;
328
329                 rq->rx_nb_hold++;
330
331                 if (!(enic_cq_rx_desc_eop(ciflags))) {
332                         last_seg = rxmb;
333                         continue;
334                 }
335
336                 /* cq rx flags are only valid if eop bit is set */
337                 first_seg->packet_type = enic_cq_rx_flags_to_pkt_type(&cqd);
338                 enic_cq_rx_to_pkt_flags(&cqd, first_seg);
339
340                 if (unlikely(packet_error)) {
341                         rte_pktmbuf_free(first_seg);
342                         rte_atomic64_inc(&enic->soft_stats.rx_packet_errors);
343                         continue;
344                 }
345
346
347                 /* prefetch mbuf data for caller */
348                 rte_packet_prefetch(RTE_PTR_ADD(first_seg->buf_addr,
349                                     RTE_PKTMBUF_HEADROOM));
350
351                 /* store the mbuf address into the next entry of the array */
352                 rx_pkts[nb_rx++] = first_seg;
353         }
354
355         sop_rq->pkt_first_seg = first_seg;
356         sop_rq->pkt_last_seg = last_seg;
357
358         cq->to_clean = cq_idx;
359
360         if ((sop_rq->rx_nb_hold + data_rq->rx_nb_hold) >
361             sop_rq->rx_free_thresh) {
362                 if (data_rq->in_use) {
363                         data_rq->posted_index =
364                                 enic_ring_add(data_rq->ring.desc_count,
365                                               data_rq->posted_index,
366                                               data_rq->rx_nb_hold);
367                         data_rq->rx_nb_hold = 0;
368                 }
369                 sop_rq->posted_index = enic_ring_add(sop_rq->ring.desc_count,
370                                                      sop_rq->posted_index,
371                                                      sop_rq->rx_nb_hold);
372                 sop_rq->rx_nb_hold = 0;
373
374                 rte_mb();
375                 if (data_rq->in_use)
376                         iowrite32(data_rq->posted_index,
377                                   &data_rq->ctrl->posted_index);
378                 rte_compiler_barrier();
379                 iowrite32(sop_rq->posted_index, &sop_rq->ctrl->posted_index);
380         }
381
382
383         return nb_rx;
384 }
385
386 static inline void enic_free_wq_bufs(struct vnic_wq *wq, u16 completed_index)
387 {
388         struct vnic_wq_buf *buf;
389         struct rte_mbuf *m, *free[ENIC_MAX_WQ_DESCS];
390         unsigned int nb_to_free, nb_free = 0, i;
391         struct rte_mempool *pool;
392         unsigned int tail_idx;
393         unsigned int desc_count = wq->ring.desc_count;
394
395         nb_to_free = enic_ring_sub(desc_count, wq->tail_idx, completed_index)
396                                    + 1;
397         tail_idx = wq->tail_idx;
398         buf = &wq->bufs[tail_idx];
399         pool = ((struct rte_mbuf *)buf->mb)->pool;
400         for (i = 0; i < nb_to_free; i++) {
401                 buf = &wq->bufs[tail_idx];
402                 m = __rte_pktmbuf_prefree_seg((struct rte_mbuf *)(buf->mb));
403                 buf->mb = NULL;
404
405                 if (unlikely(m == NULL)) {
406                         tail_idx = enic_ring_incr(desc_count, tail_idx);
407                         continue;
408                 }
409
410                 if (likely(m->pool == pool)) {
411                         RTE_ASSERT(nb_free < ENIC_MAX_WQ_DESCS);
412                         free[nb_free++] = m;
413                 } else {
414                         rte_mempool_put_bulk(pool, (void *)free, nb_free);
415                         free[0] = m;
416                         nb_free = 1;
417                         pool = m->pool;
418                 }
419                 tail_idx = enic_ring_incr(desc_count, tail_idx);
420         }
421
422         rte_mempool_put_bulk(pool, (void **)free, nb_free);
423
424         wq->tail_idx = tail_idx;
425         wq->ring.desc_avail += nb_to_free;
426 }
427
428 unsigned int enic_cleanup_wq(__rte_unused struct enic *enic, struct vnic_wq *wq)
429 {
430         u16 completed_index;
431
432         completed_index = *((uint32_t *)wq->cqmsg_rz->addr) & 0xffff;
433
434         if (wq->last_completed_index != completed_index) {
435                 enic_free_wq_bufs(wq, completed_index);
436                 wq->last_completed_index = completed_index;
437         }
438         return 0;
439 }
440
441 uint16_t enic_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
442         uint16_t nb_pkts)
443 {
444         uint16_t index;
445         unsigned int pkt_len, data_len;
446         unsigned int nb_segs;
447         struct rte_mbuf *tx_pkt;
448         struct vnic_wq *wq = (struct vnic_wq *)tx_queue;
449         struct enic *enic = vnic_dev_priv(wq->vdev);
450         unsigned short vlan_id;
451         uint64_t ol_flags;
452         uint64_t ol_flags_mask;
453         unsigned int wq_desc_avail;
454         int head_idx;
455         struct vnic_wq_buf *buf;
456         unsigned int desc_count;
457         struct wq_enet_desc *descs, *desc_p, desc_tmp;
458         uint16_t mss;
459         uint8_t vlan_tag_insert;
460         uint8_t eop;
461         uint64_t bus_addr;
462
463         enic_cleanup_wq(enic, wq);
464         wq_desc_avail = vnic_wq_desc_avail(wq);
465         head_idx = wq->head_idx;
466         desc_count = wq->ring.desc_count;
467         ol_flags_mask = PKT_TX_VLAN_PKT | PKT_TX_IP_CKSUM | PKT_TX_L4_MASK;
468
469         nb_pkts = RTE_MIN(nb_pkts, ENIC_TX_XMIT_MAX);
470
471         for (index = 0; index < nb_pkts; index++) {
472                 tx_pkt = *tx_pkts++;
473                 nb_segs = tx_pkt->nb_segs;
474                 if (nb_segs > wq_desc_avail) {
475                         if (index > 0)
476                                 goto post;
477                         goto done;
478                 }
479
480                 pkt_len = tx_pkt->pkt_len;
481                 data_len = tx_pkt->data_len;
482                 ol_flags = tx_pkt->ol_flags;
483                 mss = 0;
484                 vlan_id = 0;
485                 vlan_tag_insert = 0;
486                 bus_addr = (dma_addr_t)
487                            (tx_pkt->buf_physaddr + tx_pkt->data_off);
488
489                 descs = (struct wq_enet_desc *)wq->ring.descs;
490                 desc_p = descs + head_idx;
491
492                 eop = (data_len == pkt_len);
493
494                 if (ol_flags & ol_flags_mask) {
495                         if (ol_flags & PKT_TX_VLAN_PKT) {
496                                 vlan_tag_insert = 1;
497                                 vlan_id = tx_pkt->vlan_tci;
498                         }
499
500                         if (ol_flags & PKT_TX_IP_CKSUM)
501                                 mss |= ENIC_CALC_IP_CKSUM;
502
503                         /* Nic uses just 1 bit for UDP and TCP */
504                         switch (ol_flags & PKT_TX_L4_MASK) {
505                         case PKT_TX_TCP_CKSUM:
506                         case PKT_TX_UDP_CKSUM:
507                                 mss |= ENIC_CALC_TCP_UDP_CKSUM;
508                                 break;
509                         }
510                 }
511
512                 wq_enet_desc_enc(&desc_tmp, bus_addr, data_len, mss, 0, 0, eop,
513                                  eop, 0, vlan_tag_insert, vlan_id, 0);
514
515                 *desc_p = desc_tmp;
516                 buf = &wq->bufs[head_idx];
517                 buf->mb = (void *)tx_pkt;
518                 head_idx = enic_ring_incr(desc_count, head_idx);
519                 wq_desc_avail--;
520
521                 if (!eop) {
522                         for (tx_pkt = tx_pkt->next; tx_pkt; tx_pkt =
523                             tx_pkt->next) {
524                                 data_len = tx_pkt->data_len;
525
526                                 if (tx_pkt->next == NULL)
527                                         eop = 1;
528                                 desc_p = descs + head_idx;
529                                 bus_addr = (dma_addr_t)(tx_pkt->buf_physaddr
530                                            + tx_pkt->data_off);
531                                 wq_enet_desc_enc((struct wq_enet_desc *)
532                                                  &desc_tmp, bus_addr, data_len,
533                                                  mss, 0, 0, eop, eop, 0,
534                                                  vlan_tag_insert, vlan_id, 0);
535
536                                 *desc_p = desc_tmp;
537                                 buf = &wq->bufs[head_idx];
538                                 buf->mb = (void *)tx_pkt;
539                                 head_idx = enic_ring_incr(desc_count, head_idx);
540                                 wq_desc_avail--;
541                         }
542                 }
543         }
544  post:
545         rte_wmb();
546         iowrite32(head_idx, &wq->ctrl->posted_index);
547  done:
548         wq->ring.desc_avail = wq_desc_avail;
549         wq->head_idx = head_idx;
550
551         return index;
552 }
553
554