drivers/net/ethernet/synopsys/dwc-xlgmac-desc.c

   1 /* Synopsys DesignWare Core Enterprise Ethernet (XLGMAC) Driver
   2  *
   3  * Copyright (c) 2017 Synopsys, Inc. (www.synopsys.com)
   4  *
   5  * This program is dual-licensed; you may select either version 2 of
   6  * the GNU General Public License ("GPL") or BSD license ("BSD").
   7  *
   8  * This Synopsys DWC XLGMAC software driver and associated documentation
   9  * (hereinafter the "Software") is an unsupported proprietary work of
  10  * Synopsys, Inc. unless otherwise expressly agreed to in writing between
  11  * Synopsys and you. The Software IS NOT an item of Licensed Software or a
  12  * Licensed Product under any End User Software License Agreement or
  13  * Agreement for Licensed Products with Synopsys or any supplement thereto.
  14  * Synopsys is a registered trademark of Synopsys, Inc. Other names included
  15  * in the SOFTWARE may be the trademarks of their respective owners.
  16  */
  17
  18 #include "dwc-xlgmac.h"
  19 #include "dwc-xlgmac-reg.h"
  20
  21 static void xlgmac_unmap_desc_data(struct xlgmac_pdata *pdata,
  22                                    struct xlgmac_desc_data *desc_data)
  23 {
  24         if (desc_data->skb_dma) {
  25                 if (desc_data->mapped_as_page) {
  26                         dma_unmap_page(pdata->dev, desc_data->skb_dma,
  27                                        desc_data->skb_dma_len, DMA_TO_DEVICE);
  28                 } else {
  29                         dma_unmap_single(pdata->dev, desc_data->skb_dma,
  30                                          desc_data->skb_dma_len, DMA_TO_DEVICE);
  31                 }
  32                 desc_data->skb_dma = 0;
  33                 desc_data->skb_dma_len = 0;
  34         }
  35
  36         if (desc_data->skb) {
  37                 dev_kfree_skb_any(desc_data->skb);
  38                 desc_data->skb = NULL;
  39         }
  40
  41         if (desc_data->rx.hdr.pa.pages)
  42                 put_page(desc_data->rx.hdr.pa.pages);
  43
  44         if (desc_data->rx.hdr.pa_unmap.pages) {
  45                 dma_unmap_page(pdata->dev, desc_data->rx.hdr.pa_unmap.pages_dma,
  46                                desc_data->rx.hdr.pa_unmap.pages_len,
  47                                DMA_FROM_DEVICE);
  48                 put_page(desc_data->rx.hdr.pa_unmap.pages);
  49         }
  50
  51         if (desc_data->rx.buf.pa.pages)
  52                 put_page(desc_data->rx.buf.pa.pages);
  53
  54         if (desc_data->rx.buf.pa_unmap.pages) {
  55                 dma_unmap_page(pdata->dev, desc_data->rx.buf.pa_unmap.pages_dma,
  56                                desc_data->rx.buf.pa_unmap.pages_len,
  57                                DMA_FROM_DEVICE);
  58                 put_page(desc_data->rx.buf.pa_unmap.pages);
  59         }
  60
  61         memset(&desc_data->tx, 0, sizeof(desc_data->tx));
  62         memset(&desc_data->rx, 0, sizeof(desc_data->rx));
  63
  64         desc_data->mapped_as_page = 0;
  65
  66         if (desc_data->state_saved) {
  67                 desc_data->state_saved = 0;
  68                 desc_data->state.skb = NULL;
  69                 desc_data->state.len = 0;
  70                 desc_data->state.error = 0;
  71         }
  72 }
  73
  74 static void xlgmac_free_ring(struct xlgmac_pdata *pdata,
  75                              struct xlgmac_ring *ring)
  76 {
  77         struct xlgmac_desc_data *desc_data;
  78         unsigned int i;
  79
  80         if (!ring)
  81                 return;
  82
  83         if (ring->desc_data_head) {
  84                 for (i = 0; i < ring->dma_desc_count; i++) {
  85                         desc_data = XLGMAC_GET_DESC_DATA(ring, i);
  86                         xlgmac_unmap_desc_data(pdata, desc_data);
  87                 }
  88
  89                 kfree(ring->desc_data_head);
  90                 ring->desc_data_head = NULL;
  91         }
  92
  93         if (ring->rx_hdr_pa.pages) {
  94                 dma_unmap_page(pdata->dev, ring->rx_hdr_pa.pages_dma,
  95                                ring->rx_hdr_pa.pages_len, DMA_FROM_DEVICE);
  96                 put_page(ring->rx_hdr_pa.pages);
  97
  98                 ring->rx_hdr_pa.pages = NULL;
  99                 ring->rx_hdr_pa.pages_len = 0;
 100                 ring->rx_hdr_pa.pages_offset = 0;
 101                 ring->rx_hdr_pa.pages_dma = 0;
 102         }
 103
 104         if (ring->rx_buf_pa.pages) {
 105                 dma_unmap_page(pdata->dev, ring->rx_buf_pa.pages_dma,
 106                                ring->rx_buf_pa.pages_len, DMA_FROM_DEVICE);
 107                 put_page(ring->rx_buf_pa.pages);
 108
 109                 ring->rx_buf_pa.pages = NULL;
 110                 ring->rx_buf_pa.pages_len = 0;
 111                 ring->rx_buf_pa.pages_offset = 0;
 112                 ring->rx_buf_pa.pages_dma = 0;
 113         }
 114
 115         if (ring->dma_desc_head) {
 116                 dma_free_coherent(pdata->dev,
 117                                   (sizeof(struct xlgmac_dma_desc) *
 118                                   ring->dma_desc_count),
 119                                   ring->dma_desc_head,
 120                                   ring->dma_desc_head_addr);
 121                 ring->dma_desc_head = NULL;
 122         }
 123 }
 124
 125 static int xlgmac_init_ring(struct xlgmac_pdata *pdata,
 126                             struct xlgmac_ring *ring,
 127                             unsigned int dma_desc_count)
 128 {
 129         if (!ring)
 130                 return 0;
 131
 132         /* Descriptors */
 133         ring->dma_desc_count = dma_desc_count;
 134         ring->dma_desc_head = dma_alloc_coherent(pdata->dev,
 135                                         (sizeof(struct xlgmac_dma_desc) *
 136                                          dma_desc_count),
 137                                         &ring->dma_desc_head_addr,
 138                                         GFP_KERNEL);
 139         if (!ring->dma_desc_head)
 140                 return -ENOMEM;
 141
 142         /* Array of descriptor data */
 143         ring->desc_data_head = kcalloc(dma_desc_count,
 144                                         sizeof(struct xlgmac_desc_data),
 145                                         GFP_KERNEL);
 146         if (!ring->desc_data_head)
 147                 return -ENOMEM;
 148
 149         netif_dbg(pdata, drv, pdata->netdev,
 150                   "dma_desc_head=%p, dma_desc_head_addr=%pad, desc_data_head=%p\n",
 151                 ring->dma_desc_head,
 152                 &ring->dma_desc_head_addr,
 153                 ring->desc_data_head);
 154
 155         return 0;
 156 }
 157
 158 static void xlgmac_free_rings(struct xlgmac_pdata *pdata)
 159 {
 160         struct xlgmac_channel *channel;
 161         unsigned int i;
 162
 163         if (!pdata->channel_head)
 164                 return;
 165
 166         channel = pdata->channel_head;
 167         for (i = 0; i < pdata->channel_count; i++, channel++) {
 168                 xlgmac_free_ring(pdata, channel->tx_ring);
 169                 xlgmac_free_ring(pdata, channel->rx_ring);
 170         }
 171 }
 172
 173 static int xlgmac_alloc_rings(struct xlgmac_pdata *pdata)
 174 {
 175         struct xlgmac_channel *channel;
 176         unsigned int i;
 177         int ret;
 178
 179         channel = pdata->channel_head;
 180         for (i = 0; i < pdata->channel_count; i++, channel++) {
 181                 netif_dbg(pdata, drv, pdata->netdev, "%s - Tx ring:\n",
 182                           channel->name);
 183
 184                 ret = xlgmac_init_ring(pdata, channel->tx_ring,
 185                                        pdata->tx_desc_count);
 186
 187                 if (ret) {
 188                         netdev_alert(pdata->netdev,
 189                                      "error initializing Tx ring");
 190                         goto err_init_ring;
 191                 }
 192
 193                 netif_dbg(pdata, drv, pdata->netdev, "%s - Rx ring:\n",
 194                           channel->name);
 195
 196                 ret = xlgmac_init_ring(pdata, channel->rx_ring,
 197                                        pdata->rx_desc_count);
 198                 if (ret) {
 199                         netdev_alert(pdata->netdev,
 200                                      "error initializing Rx ring\n");
 201                         goto err_init_ring;
 202                 }
 203         }
 204
 205         return 0;
 206
 207 err_init_ring:
 208         xlgmac_free_rings(pdata);
 209
 210         return ret;
 211 }
 212
 213 static void xlgmac_free_channels(struct xlgmac_pdata *pdata)
 214 {
 215         if (!pdata->channel_head)
 216                 return;
 217
 218         kfree(pdata->channel_head->tx_ring);
 219         pdata->channel_head->tx_ring = NULL;
 220
 221         kfree(pdata->channel_head->rx_ring);
 222         pdata->channel_head->rx_ring = NULL;
 223
 224         kfree(pdata->channel_head);
 225
 226         pdata->channel_head = NULL;
 227         pdata->channel_count = 0;
 228 }
 229
 230 static int xlgmac_alloc_channels(struct xlgmac_pdata *pdata)
 231 {
 232         struct xlgmac_channel *channel_head, *channel;
 233         struct xlgmac_ring *tx_ring, *rx_ring;
 234         int ret = -ENOMEM;
 235         unsigned int i;
 236
 237         channel_head = kcalloc(pdata->channel_count,
 238                                sizeof(struct xlgmac_channel), GFP_KERNEL);
 239         if (!channel_head)
 240                 return ret;
 241
 242         netif_dbg(pdata, drv, pdata->netdev,
 243                   "channel_head=%p\n", channel_head);
 244
 245         tx_ring = kcalloc(pdata->tx_ring_count, sizeof(struct xlgmac_ring),
 246                           GFP_KERNEL);
 247         if (!tx_ring)
 248                 goto err_tx_ring;
 249
 250         rx_ring = kcalloc(pdata->rx_ring_count, sizeof(struct xlgmac_ring),
 251                           GFP_KERNEL);
 252         if (!rx_ring)
 253                 goto err_rx_ring;
 254
 255         for (i = 0, channel = channel_head; i < pdata->channel_count;
 256                 i++, channel++) {
 257                 snprintf(channel->name, sizeof(channel->name), "channel-%u", i);
 258                 channel->pdata = pdata;
 259                 channel->queue_index = i;
 260                 channel->dma_regs = pdata->mac_regs + DMA_CH_BASE +
 261                                     (DMA_CH_INC * i);
 262
 263                 if (pdata->per_channel_irq) {
 264                         /* Get the per DMA interrupt */
 265                         ret = pdata->channel_irq[i];
 266                         if (ret < 0) {
 267                                 netdev_err(pdata->netdev,
 268                                            "get_irq %u failed\n",
 269                                            i + 1);
 270                                 goto err_irq;
 271                         }
 272                         channel->dma_irq = ret;
 273                 }
 274
 275                 if (i < pdata->tx_ring_count)
 276                         channel->tx_ring = tx_ring++;
 277
 278                 if (i < pdata->rx_ring_count)
 279                         channel->rx_ring = rx_ring++;
 280
 281                 netif_dbg(pdata, drv, pdata->netdev,
 282                           "%s: dma_regs=%p, tx_ring=%p, rx_ring=%p\n",
 283                           channel->name, channel->dma_regs,
 284                           channel->tx_ring, channel->rx_ring);
 285         }
 286
 287         pdata->channel_head = channel_head;
 288
 289         return 0;
 290
 291 err_irq:
 292         kfree(rx_ring);
 293
 294 err_rx_ring:
 295         kfree(tx_ring);
 296
 297 err_tx_ring:
 298         kfree(channel_head);
 299
 300         return ret;
 301 }
 302
 303 static void xlgmac_free_channels_and_rings(struct xlgmac_pdata *pdata)
 304 {
 305         xlgmac_free_rings(pdata);
 306
 307         xlgmac_free_channels(pdata);
 308 }
 309
 310 static int xlgmac_alloc_channels_and_rings(struct xlgmac_pdata *pdata)
 311 {
 312         int ret;
 313
 314         ret = xlgmac_alloc_channels(pdata);
 315         if (ret)
 316                 goto err_alloc;
 317
 318         ret = xlgmac_alloc_rings(pdata);
 319         if (ret)
 320                 goto err_alloc;
 321
 322         return 0;
 323
 324 err_alloc:
 325         xlgmac_free_channels_and_rings(pdata);
 326
 327         return ret;
 328 }
 329
 330 static int xlgmac_alloc_pages(struct xlgmac_pdata *pdata,
 331                               struct xlgmac_page_alloc *pa,
 332                               gfp_t gfp, int order)
 333 {
 334         struct page *pages = NULL;
 335         dma_addr_t pages_dma;
 336
 337         /* Try to obtain pages, decreasing order if necessary */
 338         gfp |= __GFP_COMP | __GFP_NOWARN;
 339         while (order >= 0) {
 340                 pages = alloc_pages(gfp, order);
 341                 if (pages)
 342                         break;
 343
 344                 order--;
 345         }
 346         if (!pages)
 347                 return -ENOMEM;
 348
 349         /* Map the pages */
 350         pages_dma = dma_map_page(pdata->dev, pages, 0,
 351                                  PAGE_SIZE << order, DMA_FROM_DEVICE);
 352         if (dma_mapping_error(pdata->dev, pages_dma)) {
 353                 put_page(pages);
 354                 return -ENOMEM;
 355         }
 356
 357         pa->pages = pages;
 358         pa->pages_len = PAGE_SIZE << order;
 359         pa->pages_offset = 0;
 360         pa->pages_dma = pages_dma;
 361
 362         return 0;
 363 }
 364
 365 static void xlgmac_set_buffer_data(struct xlgmac_buffer_data *bd,
 366                                    struct xlgmac_page_alloc *pa,
 367                                    unsigned int len)
 368 {
 369         get_page(pa->pages);
 370         bd->pa = *pa;
 371
 372         bd->dma_base = pa->pages_dma;
 373         bd->dma_off = pa->pages_offset;
 374         bd->dma_len = len;
 375
 376         pa->pages_offset += len;
 377         if ((pa->pages_offset + len) > pa->pages_len) {
 378                 /* This data descriptor is responsible for unmapping page(s) */
 379                 bd->pa_unmap = *pa;
 380
 381                 /* Get a new allocation next time */
 382                 pa->pages = NULL;
 383                 pa->pages_len = 0;
 384                 pa->pages_offset = 0;
 385                 pa->pages_dma = 0;
 386         }
 387 }
 388
 389 static int xlgmac_map_rx_buffer(struct xlgmac_pdata *pdata,
 390                                 struct xlgmac_ring *ring,
 391                                 struct xlgmac_desc_data *desc_data)
 392 {
 393         int order, ret;
 394
 395         if (!ring->rx_hdr_pa.pages) {
 396                 ret = xlgmac_alloc_pages(pdata, &ring->rx_hdr_pa,
 397                                          GFP_ATOMIC, 0);
 398                 if (ret)
 399                         return ret;
 400         }
 401
 402         if (!ring->rx_buf_pa.pages) {
 403                 order = max_t(int, PAGE_ALLOC_COSTLY_ORDER - 1, 0);
 404                 ret = xlgmac_alloc_pages(pdata, &ring->rx_buf_pa,
 405                                          GFP_ATOMIC, order);
 406                 if (ret)
 407                         return ret;
 408         }
 409
 410         /* Set up the header page info */
 411         xlgmac_set_buffer_data(&desc_data->rx.hdr, &ring->rx_hdr_pa,
 412                                XLGMAC_SKB_ALLOC_SIZE);
 413
 414         /* Set up the buffer page info */
 415         xlgmac_set_buffer_data(&desc_data->rx.buf, &ring->rx_buf_pa,
 416                                pdata->rx_buf_size);
 417
 418         return 0;
 419 }
 420
 421 static void xlgmac_tx_desc_init(struct xlgmac_pdata *pdata)
 422 {
 423         struct xlgmac_hw_ops *hw_ops = &pdata->hw_ops;
 424         struct xlgmac_desc_data *desc_data;
 425         struct xlgmac_dma_desc *dma_desc;
 426         struct xlgmac_channel *channel;
 427         struct xlgmac_ring *ring;
 428         dma_addr_t dma_desc_addr;
 429         unsigned int i, j;
 430
 431         channel = pdata->channel_head;
 432         for (i = 0; i < pdata->channel_count; i++, channel++) {
 433                 ring = channel->tx_ring;
 434                 if (!ring)
 435                         break;
 436
 437                 dma_desc = ring->dma_desc_head;
 438                 dma_desc_addr = ring->dma_desc_head_addr;
 439
 440                 for (j = 0; j < ring->dma_desc_count; j++) {
 441                         desc_data = XLGMAC_GET_DESC_DATA(ring, j);
 442
 443                         desc_data->dma_desc = dma_desc;
 444                         desc_data->dma_desc_addr = dma_desc_addr;
 445
 446                         dma_desc++;
 447                         dma_desc_addr += sizeof(struct xlgmac_dma_desc);
 448                 }
 449
 450                 ring->cur = 0;
 451                 ring->dirty = 0;
 452                 memset(&ring->tx, 0, sizeof(ring->tx));
 453
 454                 hw_ops->tx_desc_init(channel);
 455         }
 456 }
 457
 458 static void xlgmac_rx_desc_init(struct xlgmac_pdata *pdata)
 459 {
 460         struct xlgmac_hw_ops *hw_ops = &pdata->hw_ops;
 461         struct xlgmac_desc_data *desc_data;
 462         struct xlgmac_dma_desc *dma_desc;
 463         struct xlgmac_channel *channel;
 464         struct xlgmac_ring *ring;
 465         dma_addr_t dma_desc_addr;
 466         unsigned int i, j;
 467
 468         channel = pdata->channel_head;
 469         for (i = 0; i < pdata->channel_count; i++, channel++) {
 470                 ring = channel->rx_ring;
 471                 if (!ring)
 472                         break;
 473
 474                 dma_desc = ring->dma_desc_head;
 475                 dma_desc_addr = ring->dma_desc_head_addr;
 476
 477                 for (j = 0; j < ring->dma_desc_count; j++) {
 478                         desc_data = XLGMAC_GET_DESC_DATA(ring, j);
 479
 480                         desc_data->dma_desc = dma_desc;
 481                         desc_data->dma_desc_addr = dma_desc_addr;
 482
 483                         if (xlgmac_map_rx_buffer(pdata, ring, desc_data))
 484                                 break;
 485
 486                         dma_desc++;
 487                         dma_desc_addr += sizeof(struct xlgmac_dma_desc);
 488                 }
 489
 490                 ring->cur = 0;
 491                 ring->dirty = 0;
 492
 493                 hw_ops->rx_desc_init(channel);
 494         }
 495 }
 496
 497 static int xlgmac_map_tx_skb(struct xlgmac_channel *channel,
 498                              struct sk_buff *skb)
 499 {
 500         struct xlgmac_pdata *pdata = channel->pdata;
 501         struct xlgmac_ring *ring = channel->tx_ring;
 502         unsigned int start_index, cur_index;
 503         struct xlgmac_desc_data *desc_data;
 504         unsigned int offset, datalen, len;
 505         struct xlgmac_pkt_info *pkt_info;
 506         struct skb_frag_struct *frag;
 507         unsigned int tso, vlan;
 508         dma_addr_t skb_dma;
 509         unsigned int i;
 510
 511         offset = 0;
 512         start_index = ring->cur;
 513         cur_index = ring->cur;
 514
 515         pkt_info = &ring->pkt_info;
 516         pkt_info->desc_count = 0;
 517         pkt_info->length = 0;
 518
 519         tso = XLGMAC_GET_REG_BITS(pkt_info->attributes,
 520                                   TX_PACKET_ATTRIBUTES_TSO_ENABLE_POS,
 521                                   TX_PACKET_ATTRIBUTES_TSO_ENABLE_LEN);
 522         vlan = XLGMAC_GET_REG_BITS(pkt_info->attributes,
 523                                    TX_PACKET_ATTRIBUTES_VLAN_CTAG_POS,
 524                                    TX_PACKET_ATTRIBUTES_VLAN_CTAG_LEN);
 525
 526         /* Save space for a context descriptor if needed */
 527         if ((tso && (pkt_info->mss != ring->tx.cur_mss)) ||
 528             (vlan && (pkt_info->vlan_ctag != ring->tx.cur_vlan_ctag)))
 529                 cur_index++;
 530         desc_data = XLGMAC_GET_DESC_DATA(ring, cur_index);
 531
 532         if (tso) {
 533                 /* Map the TSO header */
 534                 skb_dma = dma_map_single(pdata->dev, skb->data,
 535                                          pkt_info->header_len, DMA_TO_DEVICE);
 536                 if (dma_mapping_error(pdata->dev, skb_dma)) {
 537                         netdev_alert(pdata->netdev, "dma_map_single failed\n");
 538                         goto err_out;
 539                 }
 540                 desc_data->skb_dma = skb_dma;
 541                 desc_data->skb_dma_len = pkt_info->header_len;
 542                 netif_dbg(pdata, tx_queued, pdata->netdev,
 543                           "skb header: index=%u, dma=%pad, len=%u\n",
 544                           cur_index, &skb_dma, pkt_info->header_len);
 545
 546                 offset = pkt_info->header_len;
 547
 548                 pkt_info->length += pkt_info->header_len;
 549
 550                 cur_index++;
 551                 desc_data = XLGMAC_GET_DESC_DATA(ring, cur_index);
 552         }
 553
 554         /* Map the (remainder of the) packet */
 555         for (datalen = skb_headlen(skb) - offset; datalen; ) {
 556                 len = min_t(unsigned int, datalen, XLGMAC_TX_MAX_BUF_SIZE);
 557
 558                 skb_dma = dma_map_single(pdata->dev, skb->data + offset, len,
 559                                          DMA_TO_DEVICE);
 560                 if (dma_mapping_error(pdata->dev, skb_dma)) {
 561                         netdev_alert(pdata->netdev, "dma_map_single failed\n");
 562                         goto err_out;
 563                 }
 564                 desc_data->skb_dma = skb_dma;
 565                 desc_data->skb_dma_len = len;
 566                 netif_dbg(pdata, tx_queued, pdata->netdev,
 567                           "skb data: index=%u, dma=%pad, len=%u\n",
 568                           cur_index, &skb_dma, len);
 569
 570                 datalen -= len;
 571                 offset += len;
 572
 573                 pkt_info->length += len;
 574
 575                 cur_index++;
 576                 desc_data = XLGMAC_GET_DESC_DATA(ring, cur_index);
 577         }
 578
 579         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 580                 netif_dbg(pdata, tx_queued, pdata->netdev,
 581                           "mapping frag %u\n", i);
 582
 583                 frag = &skb_shinfo(skb)->frags[i];
 584                 offset = 0;
 585
 586                 for (datalen = skb_frag_size(frag); datalen; ) {
 587                         len = min_t(unsigned int, datalen,
 588                                     XLGMAC_TX_MAX_BUF_SIZE);
 589
 590                         skb_dma = skb_frag_dma_map(pdata->dev, frag, offset,
 591                                                    len, DMA_TO_DEVICE);
 592                         if (dma_mapping_error(pdata->dev, skb_dma)) {
 593                                 netdev_alert(pdata->netdev,
 594                                              "skb_frag_dma_map failed\n");
 595                                 goto err_out;
 596                         }
 597                         desc_data->skb_dma = skb_dma;
 598                         desc_data->skb_dma_len = len;
 599                         desc_data->mapped_as_page = 1;
 600                         netif_dbg(pdata, tx_queued, pdata->netdev,
 601                                   "skb frag: index=%u, dma=%pad, len=%u\n",
 602                                   cur_index, &skb_dma, len);
 603
 604                         datalen -= len;
 605                         offset += len;
 606
 607                         pkt_info->length += len;
 608
 609                         cur_index++;
 610                         desc_data = XLGMAC_GET_DESC_DATA(ring, cur_index);
 611                 }
 612         }
 613
 614         /* Save the skb address in the last entry. We always have some data
 615          * that has been mapped so desc_data is always advanced past the last
 616          * piece of mapped data - use the entry pointed to by cur_index - 1.
 617          */
 618         desc_data = XLGMAC_GET_DESC_DATA(ring, cur_index - 1);
 619         desc_data->skb = skb;
 620
 621         /* Save the number of descriptor entries used */
 622         pkt_info->desc_count = cur_index - start_index;
 623
 624         return pkt_info->desc_count;
 625
 626 err_out:
 627         while (start_index < cur_index) {
 628                 desc_data = XLGMAC_GET_DESC_DATA(ring, start_index++);
 629                 xlgmac_unmap_desc_data(pdata, desc_data);
 630         }
 631
 632         return 0;
 633 }
 634
 635 void xlgmac_init_desc_ops(struct xlgmac_desc_ops *desc_ops)
 636 {
 637         desc_ops->alloc_channles_and_rings = xlgmac_alloc_channels_and_rings;
 638         desc_ops->free_channels_and_rings = xlgmac_free_channels_and_rings;
 639         desc_ops->map_tx_skb = xlgmac_map_tx_skb;
 640         desc_ops->map_rx_buffer = xlgmac_map_rx_buffer;
 641         desc_ops->unmap_desc_data = xlgmac_unmap_desc_data;
 642         desc_ops->tx_desc_init = xlgmac_tx_desc_init;
 643         desc_ops->rx_desc_init = xlgmac_rx_desc_init;
 644 }