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                 dma_addr = (dma_addr_t)(nmb->buf_physaddr +
 304                                         RTE_PKTMBUF_HEADROOM);
 305                 rq_enet_desc_enc(rqd_ptr, dma_addr,
 306                                 (rq->is_sop ? RQ_ENET_TYPE_ONLY_SOP
 307                                 : RQ_ENET_TYPE_NOT_SOP),
 308                                 nmb->buf_len - RTE_PKTMBUF_HEADROOM);
 309
 310                 /* Fill in the rest of the mbuf */
 311                 seg_length = enic_cq_rx_desc_n_bytes(&cqd);
 312
 313                 if (rq->is_sop) {
 314                         first_seg = rxmb;
 315                         first_seg->nb_segs = 1;
 316                         first_seg->pkt_len = seg_length;
 317                 } else {
 318                         first_seg->pkt_len = (uint16_t)(first_seg->pkt_len
 319                                                         + seg_length);
 320                         first_seg->nb_segs++;
 321                         last_seg->next = rxmb;
 322                 }
 323
 324                 rxmb->next = NULL;
 325                 rxmb->port = enic->port_id;
 326                 rxmb->data_len = seg_length;
 327
 328                 rq->rx_nb_hold++;
 329
 330                 if (!(enic_cq_rx_desc_eop(ciflags))) {
 331                         last_seg = rxmb;
 332                         continue;
 333                 }
 334
 335                 /* cq rx flags are only valid if eop bit is set */
 336                 first_seg->packet_type = enic_cq_rx_flags_to_pkt_type(&cqd);
 337                 enic_cq_rx_to_pkt_flags(&cqd, first_seg);
 338
 339                 if (unlikely(packet_error)) {
 340                         rte_pktmbuf_free(first_seg);
 341                         rte_atomic64_inc(&enic->soft_stats.rx_packet_errors);
 342                         continue;
 343                 }
 344
 345
 346                 /* prefetch mbuf data for caller */
 347                 rte_packet_prefetch(RTE_PTR_ADD(first_seg->buf_addr,
 348                                     RTE_PKTMBUF_HEADROOM));
 349
 350                 /* store the mbuf address into the next entry of the array */
 351                 rx_pkts[nb_rx++] = first_seg;
 352         }
 353
 354         sop_rq->pkt_first_seg = first_seg;
 355         sop_rq->pkt_last_seg = last_seg;
 356
 357         cq->to_clean = cq_idx;
 358
 359         if ((sop_rq->rx_nb_hold + data_rq->rx_nb_hold) >
 360             sop_rq->rx_free_thresh) {
 361                 if (data_rq->in_use) {
 362                         data_rq->posted_index =
 363                                 enic_ring_add(data_rq->ring.desc_count,
 364                                               data_rq->posted_index,
 365                                               data_rq->rx_nb_hold);
 366                         data_rq->rx_nb_hold = 0;
 367                 }
 368                 sop_rq->posted_index = enic_ring_add(sop_rq->ring.desc_count,
 369                                                      sop_rq->posted_index,
 370                                                      sop_rq->rx_nb_hold);
 371                 sop_rq->rx_nb_hold = 0;
 372
 373                 rte_mb();
 374                 if (data_rq->in_use)
 375                         iowrite32(data_rq->posted_index,
 376                                   &data_rq->ctrl->posted_index);
 377                 rte_compiler_barrier();
 378                 iowrite32(sop_rq->posted_index, &sop_rq->ctrl->posted_index);
 379         }
 380
 381
 382         return nb_rx;
 383 }
 384
 385 static inline void enic_free_wq_bufs(struct vnic_wq *wq, u16 completed_index)
 386 {
 387         struct vnic_wq_buf *buf;
 388         struct rte_mbuf *m, *free[ENIC_MAX_WQ_DESCS];
 389         unsigned int nb_to_free, nb_free = 0, i;
 390         struct rte_mempool *pool;
 391         unsigned int tail_idx;
 392         unsigned int desc_count = wq->ring.desc_count;
 393
 394         nb_to_free = enic_ring_sub(desc_count, wq->tail_idx, completed_index)
 395                                    + 1;
 396         tail_idx = wq->tail_idx;
 397         buf = &wq->bufs[tail_idx];
 398         pool = ((struct rte_mbuf *)buf->mb)->pool;
 399         for (i = 0; i < nb_to_free; i++) {
 400                 buf = &wq->bufs[tail_idx];
 401                 m = (struct rte_mbuf *)(buf->mb);
 402                 if (likely(m->pool == pool)) {
 403                         ENIC_ASSERT(nb_free < ENIC_MAX_WQ_DESCS);
 404                         free[nb_free++] = m;
 405                 } else {
 406                         rte_mempool_put_bulk(pool, (void *)free, nb_free);
 407                         free[0] = m;
 408                         nb_free = 1;
 409                         pool = m->pool;
 410                 }
 411                 tail_idx = enic_ring_incr(desc_count, tail_idx);
 412                 buf->mb = NULL;
 413         }
 414
 415         rte_mempool_put_bulk(pool, (void **)free, nb_free);
 416
 417         wq->tail_idx = tail_idx;
 418         wq->ring.desc_avail += nb_to_free;
 419 }
 420
 421 unsigned int enic_cleanup_wq(__rte_unused struct enic *enic, struct vnic_wq *wq)
 422 {
 423         u16 completed_index;
 424
 425         completed_index = *((uint32_t *)wq->cqmsg_rz->addr) & 0xffff;
 426
 427         if (wq->last_completed_index != completed_index) {
 428                 enic_free_wq_bufs(wq, completed_index);
 429                 wq->last_completed_index = completed_index;
 430         }
 431         return 0;
 432 }
 433
 434 uint16_t enic_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
 435         uint16_t nb_pkts)
 436 {
 437         uint16_t index;
 438         unsigned int pkt_len, data_len;
 439         unsigned int nb_segs;
 440         struct rte_mbuf *tx_pkt;
 441         struct vnic_wq *wq = (struct vnic_wq *)tx_queue;
 442         struct enic *enic = vnic_dev_priv(wq->vdev);
 443         unsigned short vlan_id;
 444         uint64_t ol_flags;
 445         uint64_t ol_flags_mask;
 446         unsigned int wq_desc_avail;
 447         int head_idx;
 448         struct vnic_wq_buf *buf;
 449         unsigned int desc_count;
 450         struct wq_enet_desc *descs, *desc_p, desc_tmp;
 451         uint16_t mss;
 452         uint8_t vlan_tag_insert;
 453         uint8_t eop;
 454         uint64_t bus_addr;
 455
 456         enic_cleanup_wq(enic, wq);
 457         wq_desc_avail = vnic_wq_desc_avail(wq);
 458         head_idx = wq->head_idx;
 459         desc_count = wq->ring.desc_count;
 460         ol_flags_mask = PKT_TX_VLAN_PKT | PKT_TX_IP_CKSUM | PKT_TX_L4_MASK;
 461
 462         nb_pkts = RTE_MIN(nb_pkts, ENIC_TX_XMIT_MAX);
 463
 464         for (index = 0; index < nb_pkts; index++) {
 465                 tx_pkt = *tx_pkts++;
 466                 nb_segs = tx_pkt->nb_segs;
 467                 if (nb_segs > wq_desc_avail) {
 468                         if (index > 0)
 469                                 goto post;
 470                         goto done;
 471                 }
 472
 473                 pkt_len = tx_pkt->pkt_len;
 474                 data_len = tx_pkt->data_len;
 475                 ol_flags = tx_pkt->ol_flags;
 476                 mss = 0;
 477                 vlan_id = 0;
 478                 vlan_tag_insert = 0;
 479                 bus_addr = (dma_addr_t)
 480                            (tx_pkt->buf_physaddr + tx_pkt->data_off);
 481
 482                 descs = (struct wq_enet_desc *)wq->ring.descs;
 483                 desc_p = descs + head_idx;
 484
 485                 eop = (data_len == pkt_len);
 486
 487                 if (ol_flags & ol_flags_mask) {
 488                         if (ol_flags & PKT_TX_VLAN_PKT) {
 489                                 vlan_tag_insert = 1;
 490                                 vlan_id = tx_pkt->vlan_tci;
 491                         }
 492
 493                         if (ol_flags & PKT_TX_IP_CKSUM)
 494                                 mss |= ENIC_CALC_IP_CKSUM;
 495
 496                         /* Nic uses just 1 bit for UDP and TCP */
 497                         switch (ol_flags & PKT_TX_L4_MASK) {
 498                         case PKT_TX_TCP_CKSUM:
 499                         case PKT_TX_UDP_CKSUM:
 500                                 mss |= ENIC_CALC_TCP_UDP_CKSUM;
 501                                 break;
 502                         }
 503                 }
 504
 505                 wq_enet_desc_enc(&desc_tmp, bus_addr, data_len, mss, 0, 0, eop,
 506                                  eop, 0, vlan_tag_insert, vlan_id, 0);
 507
 508                 *desc_p = desc_tmp;
 509                 buf = &wq->bufs[head_idx];
 510                 buf->mb = (void *)tx_pkt;
 511                 head_idx = enic_ring_incr(desc_count, head_idx);
 512                 wq_desc_avail--;
 513
 514                 if (!eop) {
 515                         for (tx_pkt = tx_pkt->next; tx_pkt; tx_pkt =
 516                             tx_pkt->next) {
 517                                 data_len = tx_pkt->data_len;
 518
 519                                 if (tx_pkt->next == NULL)
 520                                         eop = 1;
 521                                 desc_p = descs + head_idx;
 522                                 bus_addr = (dma_addr_t)(tx_pkt->buf_physaddr
 523                                            + tx_pkt->data_off);
 524                                 wq_enet_desc_enc((struct wq_enet_desc *)
 525                                                  &desc_tmp, bus_addr, data_len,
 526                                                  mss, 0, 0, eop, eop, 0,
 527                                                  vlan_tag_insert, vlan_id, 0);
 528
 529                                 *desc_p = desc_tmp;
 530                                 buf = &wq->bufs[head_idx];
 531                                 buf->mb = (void *)tx_pkt;
 532                                 head_idx = enic_ring_incr(desc_count, head_idx);
 533                                 wq_desc_avail--;
 534                         }
 535                 }
 536         }
 537  post:
 538         rte_wmb();
 539         iowrite32(head_idx, &wq->ctrl->posted_index);
 540  done:
 541         wq->ring.desc_avail = wq_desc_avail;
 542         wq->head_idx = head_idx;
 543
 544         return index;
 545 }
 546
 547