drivers/net/ethernet/sfc/falcon/tx.c

   1 /****************************************************************************
   2  * Driver for Solarflare network controllers and boards
   3  * Copyright 2005-2006 Fen Systems Ltd.
   4  * Copyright 2005-2013 Solarflare Communications Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published
   8  * by the Free Software Foundation, incorporated herein by reference.
   9  */
  10
  11 #include <linux/pci.h>
  12 #include <linux/tcp.h>
  13 #include <linux/ip.h>
  14 #include <linux/in.h>
  15 #include <linux/ipv6.h>
  16 #include <linux/slab.h>
  17 #include <net/ipv6.h>
  18 #include <linux/if_ether.h>
  19 #include <linux/highmem.h>
  20 #include <linux/cache.h>
  21 #include "net_driver.h"
  22 #include "efx.h"
  23 #include "io.h"
  24 #include "nic.h"
  25 #include "tx.h"
  26 #include "workarounds.h"
  27
  28 static inline u8 *ef4_tx_get_copy_buffer(struct ef4_tx_queue *tx_queue,
  29                                          struct ef4_tx_buffer *buffer)
  30 {
  31         unsigned int index = ef4_tx_queue_get_insert_index(tx_queue);
  32         struct ef4_buffer *page_buf =
  33                 &tx_queue->cb_page[index >> (PAGE_SHIFT - EF4_TX_CB_ORDER)];
  34         unsigned int offset =
  35                 ((index << EF4_TX_CB_ORDER) + NET_IP_ALIGN) & (PAGE_SIZE - 1);
  36
  37         if (unlikely(!page_buf->addr) &&
  38             ef4_nic_alloc_buffer(tx_queue->efx, page_buf, PAGE_SIZE,
  39                                  GFP_ATOMIC))
  40                 return NULL;
  41         buffer->dma_addr = page_buf->dma_addr + offset;
  42         buffer->unmap_len = 0;
  43         return (u8 *)page_buf->addr + offset;
  44 }
  45
  46 u8 *ef4_tx_get_copy_buffer_limited(struct ef4_tx_queue *tx_queue,
  47                                    struct ef4_tx_buffer *buffer, size_t len)
  48 {
  49         if (len > EF4_TX_CB_SIZE)
  50                 return NULL;
  51         return ef4_tx_get_copy_buffer(tx_queue, buffer);
  52 }
  53
  54 static void ef4_dequeue_buffer(struct ef4_tx_queue *tx_queue,
  55                                struct ef4_tx_buffer *buffer,
  56                                unsigned int *pkts_compl,
  57                                unsigned int *bytes_compl)
  58 {
  59         if (buffer->unmap_len) {
  60                 struct device *dma_dev = &tx_queue->efx->pci_dev->dev;
  61                 dma_addr_t unmap_addr = buffer->dma_addr - buffer->dma_offset;
  62                 if (buffer->flags & EF4_TX_BUF_MAP_SINGLE)
  63                         dma_unmap_single(dma_dev, unmap_addr, buffer->unmap_len,
  64                                          DMA_TO_DEVICE);
  65                 else
  66                         dma_unmap_page(dma_dev, unmap_addr, buffer->unmap_len,
  67                                        DMA_TO_DEVICE);
  68                 buffer->unmap_len = 0;
  69         }
  70
  71         if (buffer->flags & EF4_TX_BUF_SKB) {
  72                 (*pkts_compl)++;
  73                 (*bytes_compl) += buffer->skb->len;
  74                 dev_consume_skb_any((struct sk_buff *)buffer->skb);
  75                 netif_vdbg(tx_queue->efx, tx_done, tx_queue->efx->net_dev,
  76                            "TX queue %d transmission id %x complete\n",
  77                            tx_queue->queue, tx_queue->read_count);
  78         }
  79
  80         buffer->len = 0;
  81         buffer->flags = 0;
  82 }
  83
  84 unsigned int ef4_tx_max_skb_descs(struct ef4_nic *efx)
  85 {
  86         /* This is probably too much since we don't have any TSO support;
  87          * it's a left-over from when we had Software TSO.  But it's safer
  88          * to leave it as-is than try to determine a new bound.
  89          */
  90         /* Header and payload descriptor for each output segment, plus
  91          * one for every input fragment boundary within a segment
  92          */
  93         unsigned int max_descs = EF4_TSO_MAX_SEGS * 2 + MAX_SKB_FRAGS;
  94
  95         /* Possibly one more per segment for the alignment workaround,
  96          * or for option descriptors
  97          */
  98         if (EF4_WORKAROUND_5391(efx))
  99                 max_descs += EF4_TSO_MAX_SEGS;
 100
 101         /* Possibly more for PCIe page boundaries within input fragments */
 102         if (PAGE_SIZE > EF4_PAGE_SIZE)
 103                 max_descs += max_t(unsigned int, MAX_SKB_FRAGS,
 104                                    DIV_ROUND_UP(GSO_MAX_SIZE, EF4_PAGE_SIZE));
 105
 106         return max_descs;
 107 }
 108
 109 static void ef4_tx_maybe_stop_queue(struct ef4_tx_queue *txq1)
 110 {
 111         /* We need to consider both queues that the net core sees as one */
 112         struct ef4_tx_queue *txq2 = ef4_tx_queue_partner(txq1);
 113         struct ef4_nic *efx = txq1->efx;
 114         unsigned int fill_level;
 115
 116         fill_level = max(txq1->insert_count - txq1->old_read_count,
 117                          txq2->insert_count - txq2->old_read_count);
 118         if (likely(fill_level < efx->txq_stop_thresh))
 119                 return;
 120
 121         /* We used the stale old_read_count above, which gives us a
 122          * pessimistic estimate of the fill level (which may even
 123          * validly be >= efx->txq_entries).  Now try again using
 124          * read_count (more likely to be a cache miss).
 125          *
 126          * If we read read_count and then conditionally stop the
 127          * queue, it is possible for the completion path to race with
 128          * us and complete all outstanding descriptors in the middle,
 129          * after which there will be no more completions to wake it.
 130          * Therefore we stop the queue first, then read read_count
 131          * (with a memory barrier to ensure the ordering), then
 132          * restart the queue if the fill level turns out to be low
 133          * enough.
 134          */
 135         netif_tx_stop_queue(txq1->core_txq);
 136         smp_mb();
 137         txq1->old_read_count = ACCESS_ONCE(txq1->read_count);
 138         txq2->old_read_count = ACCESS_ONCE(txq2->read_count);
 139
 140         fill_level = max(txq1->insert_count - txq1->old_read_count,
 141                          txq2->insert_count - txq2->old_read_count);
 142         EF4_BUG_ON_PARANOID(fill_level >= efx->txq_entries);
 143         if (likely(fill_level < efx->txq_stop_thresh)) {
 144                 smp_mb();
 145                 if (likely(!efx->loopback_selftest))
 146                         netif_tx_start_queue(txq1->core_txq);
 147         }
 148 }
 149
 150 static int ef4_enqueue_skb_copy(struct ef4_tx_queue *tx_queue,
 151                                 struct sk_buff *skb)
 152 {
 153         unsigned int min_len = tx_queue->tx_min_size;
 154         unsigned int copy_len = skb->len;
 155         struct ef4_tx_buffer *buffer;
 156         u8 *copy_buffer;
 157         int rc;
 158
 159         EF4_BUG_ON_PARANOID(copy_len > EF4_TX_CB_SIZE);
 160
 161         buffer = ef4_tx_queue_get_insert_buffer(tx_queue);
 162
 163         copy_buffer = ef4_tx_get_copy_buffer(tx_queue, buffer);
 164         if (unlikely(!copy_buffer))
 165                 return -ENOMEM;
 166
 167         rc = skb_copy_bits(skb, 0, copy_buffer, copy_len);
 168         EF4_WARN_ON_PARANOID(rc);
 169         if (unlikely(copy_len < min_len)) {
 170                 memset(copy_buffer + copy_len, 0, min_len - copy_len);
 171                 buffer->len = min_len;
 172         } else {
 173                 buffer->len = copy_len;
 174         }
 175
 176         buffer->skb = skb;
 177         buffer->flags = EF4_TX_BUF_SKB;
 178
 179         ++tx_queue->insert_count;
 180         return rc;
 181 }
 182
 183 static struct ef4_tx_buffer *ef4_tx_map_chunk(struct ef4_tx_queue *tx_queue,
 184                                               dma_addr_t dma_addr,
 185                                               size_t len)
 186 {
 187         const struct ef4_nic_type *nic_type = tx_queue->efx->type;
 188         struct ef4_tx_buffer *buffer;
 189         unsigned int dma_len;
 190
 191         /* Map the fragment taking account of NIC-dependent DMA limits. */
 192         do {
 193                 buffer = ef4_tx_queue_get_insert_buffer(tx_queue);
 194                 dma_len = nic_type->tx_limit_len(tx_queue, dma_addr, len);
 195
 196                 buffer->len = dma_len;
 197                 buffer->dma_addr = dma_addr;
 198                 buffer->flags = EF4_TX_BUF_CONT;
 199                 len -= dma_len;
 200                 dma_addr += dma_len;
 201                 ++tx_queue->insert_count;
 202         } while (len);
 203
 204         return buffer;
 205 }
 206
 207 /* Map all data from an SKB for DMA and create descriptors on the queue.
 208  */
 209 static int ef4_tx_map_data(struct ef4_tx_queue *tx_queue, struct sk_buff *skb)
 210 {
 211         struct ef4_nic *efx = tx_queue->efx;
 212         struct device *dma_dev = &efx->pci_dev->dev;
 213         unsigned int frag_index, nr_frags;
 214         dma_addr_t dma_addr, unmap_addr;
 215         unsigned short dma_flags;
 216         size_t len, unmap_len;
 217
 218         nr_frags = skb_shinfo(skb)->nr_frags;
 219         frag_index = 0;
 220
 221         /* Map header data. */
 222         len = skb_headlen(skb);
 223         dma_addr = dma_map_single(dma_dev, skb->data, len, DMA_TO_DEVICE);
 224         dma_flags = EF4_TX_BUF_MAP_SINGLE;
 225         unmap_len = len;
 226         unmap_addr = dma_addr;
 227
 228         if (unlikely(dma_mapping_error(dma_dev, dma_addr)))
 229                 return -EIO;
 230
 231         /* Add descriptors for each fragment. */
 232         do {
 233                 struct ef4_tx_buffer *buffer;
 234                 skb_frag_t *fragment;
 235
 236                 buffer = ef4_tx_map_chunk(tx_queue, dma_addr, len);
 237
 238                 /* The final descriptor for a fragment is responsible for
 239                  * unmapping the whole fragment.
 240                  */
 241                 buffer->flags = EF4_TX_BUF_CONT | dma_flags;
 242                 buffer->unmap_len = unmap_len;
 243                 buffer->dma_offset = buffer->dma_addr - unmap_addr;
 244
 245                 if (frag_index >= nr_frags) {
 246                         /* Store SKB details with the final buffer for
 247                          * the completion.
 248                          */
 249                         buffer->skb = skb;
 250                         buffer->flags = EF4_TX_BUF_SKB | dma_flags;
 251                         return 0;
 252                 }
 253
 254                 /* Move on to the next fragment. */
 255                 fragment = &skb_shinfo(skb)->frags[frag_index++];
 256                 len = skb_frag_size(fragment);
 257                 dma_addr = skb_frag_dma_map(dma_dev, fragment,
 258                                 0, len, DMA_TO_DEVICE);
 259                 dma_flags = 0;
 260                 unmap_len = len;
 261                 unmap_addr = dma_addr;
 262
 263                 if (unlikely(dma_mapping_error(dma_dev, dma_addr)))
 264                         return -EIO;
 265         } while (1);
 266 }
 267
 268 /* Remove buffers put into a tx_queue.  None of the buffers must have
 269  * an skb attached.
 270  */
 271 static void ef4_enqueue_unwind(struct ef4_tx_queue *tx_queue)
 272 {
 273         struct ef4_tx_buffer *buffer;
 274
 275         /* Work backwards until we hit the original insert pointer value */
 276         while (tx_queue->insert_count != tx_queue->write_count) {
 277                 --tx_queue->insert_count;
 278                 buffer = __ef4_tx_queue_get_insert_buffer(tx_queue);
 279                 ef4_dequeue_buffer(tx_queue, buffer, NULL, NULL);
 280         }
 281 }
 282
 283 /*
 284  * Add a socket buffer to a TX queue
 285  *
 286  * This maps all fragments of a socket buffer for DMA and adds them to
 287  * the TX queue.  The queue's insert pointer will be incremented by
 288  * the number of fragments in the socket buffer.
 289  *
 290  * If any DMA mapping fails, any mapped fragments will be unmapped,
 291  * the queue's insert pointer will be restored to its original value.
 292  *
 293  * This function is split out from ef4_hard_start_xmit to allow the
 294  * loopback test to direct packets via specific TX queues.
 295  *
 296  * Returns NETDEV_TX_OK.
 297  * You must hold netif_tx_lock() to call this function.
 298  */
 299 netdev_tx_t ef4_enqueue_skb(struct ef4_tx_queue *tx_queue, struct sk_buff *skb)
 300 {
 301         bool data_mapped = false;
 302         unsigned int skb_len;
 303
 304         skb_len = skb->len;
 305         EF4_WARN_ON_PARANOID(skb_is_gso(skb));
 306
 307         if (skb_len < tx_queue->tx_min_size ||
 308                         (skb->data_len && skb_len <= EF4_TX_CB_SIZE)) {
 309                 /* Pad short packets or coalesce short fragmented packets. */
 310                 if (ef4_enqueue_skb_copy(tx_queue, skb))
 311                         goto err;
 312                 tx_queue->cb_packets++;
 313                 data_mapped = true;
 314         }
 315
 316         /* Map for DMA and create descriptors if we haven't done so already. */
 317         if (!data_mapped && (ef4_tx_map_data(tx_queue, skb)))
 318                 goto err;
 319
 320         /* Update BQL */
 321         netdev_tx_sent_queue(tx_queue->core_txq, skb_len);
 322
 323         /* Pass off to hardware */
 324         if (!skb->xmit_more || netif_xmit_stopped(tx_queue->core_txq)) {
 325                 struct ef4_tx_queue *txq2 = ef4_tx_queue_partner(tx_queue);
 326
 327                 /* There could be packets left on the partner queue if those
 328                  * SKBs had skb->xmit_more set. If we do not push those they
 329                  * could be left for a long time and cause a netdev watchdog.
 330                  */
 331                 if (txq2->xmit_more_available)
 332                         ef4_nic_push_buffers(txq2);
 333
 334                 ef4_nic_push_buffers(tx_queue);
 335         } else {
 336                 tx_queue->xmit_more_available = skb->xmit_more;
 337         }
 338
 339         tx_queue->tx_packets++;
 340
 341         ef4_tx_maybe_stop_queue(tx_queue);
 342
 343         return NETDEV_TX_OK;
 344
 345
 346 err:
 347         ef4_enqueue_unwind(tx_queue);
 348         dev_kfree_skb_any(skb);
 349         return NETDEV_TX_OK;
 350 }
 351
 352 /* Remove packets from the TX queue
 353  *
 354  * This removes packets from the TX queue, up to and including the
 355  * specified index.
 356  */
 357 static void ef4_dequeue_buffers(struct ef4_tx_queue *tx_queue,
 358                                 unsigned int index,
 359                                 unsigned int *pkts_compl,
 360                                 unsigned int *bytes_compl)
 361 {
 362         struct ef4_nic *efx = tx_queue->efx;
 363         unsigned int stop_index, read_ptr;
 364
 365         stop_index = (index + 1) & tx_queue->ptr_mask;
 366         read_ptr = tx_queue->read_count & tx_queue->ptr_mask;
 367
 368         while (read_ptr != stop_index) {
 369                 struct ef4_tx_buffer *buffer = &tx_queue->buffer[read_ptr];
 370
 371                 if (!(buffer->flags & EF4_TX_BUF_OPTION) &&
 372                     unlikely(buffer->len == 0)) {
 373                         netif_err(efx, tx_err, efx->net_dev,
 374                                   "TX queue %d spurious TX completion id %x\n",
 375                                   tx_queue->queue, read_ptr);
 376                         ef4_schedule_reset(efx, RESET_TYPE_TX_SKIP);
 377                         return;
 378                 }
 379
 380                 ef4_dequeue_buffer(tx_queue, buffer, pkts_compl, bytes_compl);
 381
 382                 ++tx_queue->read_count;
 383                 read_ptr = tx_queue->read_count & tx_queue->ptr_mask;
 384         }
 385 }
 386
 387 /* Initiate a packet transmission.  We use one channel per CPU
 388  * (sharing when we have more CPUs than channels).  On Falcon, the TX
 389  * completion events will be directed back to the CPU that transmitted
 390  * the packet, which should be cache-efficient.
 391  *
 392  * Context: non-blocking.
 393  * Note that returning anything other than NETDEV_TX_OK will cause the
 394  * OS to free the skb.
 395  */
 396 netdev_tx_t ef4_hard_start_xmit(struct sk_buff *skb,
 397                                 struct net_device *net_dev)
 398 {
 399         struct ef4_nic *efx = netdev_priv(net_dev);
 400         struct ef4_tx_queue *tx_queue;
 401         unsigned index, type;
 402
 403         EF4_WARN_ON_PARANOID(!netif_device_present(net_dev));
 404
 405         index = skb_get_queue_mapping(skb);
 406         type = skb->ip_summed == CHECKSUM_PARTIAL ? EF4_TXQ_TYPE_OFFLOAD : 0;
 407         if (index >= efx->n_tx_channels) {
 408                 index -= efx->n_tx_channels;
 409                 type |= EF4_TXQ_TYPE_HIGHPRI;
 410         }
 411         tx_queue = ef4_get_tx_queue(efx, index, type);
 412
 413         return ef4_enqueue_skb(tx_queue, skb);
 414 }
 415
 416 void ef4_init_tx_queue_core_txq(struct ef4_tx_queue *tx_queue)
 417 {
 418         struct ef4_nic *efx = tx_queue->efx;
 419
 420         /* Must be inverse of queue lookup in ef4_hard_start_xmit() */
 421         tx_queue->core_txq =
 422                 netdev_get_tx_queue(efx->net_dev,
 423                                     tx_queue->queue / EF4_TXQ_TYPES +
 424                                     ((tx_queue->queue & EF4_TXQ_TYPE_HIGHPRI) ?
 425                                      efx->n_tx_channels : 0));
 426 }
 427
 428 int ef4_setup_tc(struct net_device *net_dev, u32 handle, __be16 proto,
 429                  struct tc_to_netdev *ntc)
 430 {
 431         struct ef4_nic *efx = netdev_priv(net_dev);
 432         struct ef4_channel *channel;
 433         struct ef4_tx_queue *tx_queue;
 434         unsigned tc, num_tc;
 435         int rc;
 436
 437         if (ntc->type != TC_SETUP_MQPRIO)
 438                 return -EINVAL;
 439
 440         num_tc = ntc->tc;
 441
 442         if (ef4_nic_rev(efx) < EF4_REV_FALCON_B0 || num_tc > EF4_MAX_TX_TC)
 443                 return -EINVAL;
 444
 445         if (num_tc == net_dev->num_tc)
 446                 return 0;
 447
 448         for (tc = 0; tc < num_tc; tc++) {
 449                 net_dev->tc_to_txq[tc].offset = tc * efx->n_tx_channels;
 450                 net_dev->tc_to_txq[tc].count = efx->n_tx_channels;
 451         }
 452
 453         if (num_tc > net_dev->num_tc) {
 454                 /* Initialise high-priority queues as necessary */
 455                 ef4_for_each_channel(channel, efx) {
 456                         ef4_for_each_possible_channel_tx_queue(tx_queue,
 457                                                                channel) {
 458                                 if (!(tx_queue->queue & EF4_TXQ_TYPE_HIGHPRI))
 459                                         continue;
 460                                 if (!tx_queue->buffer) {
 461                                         rc = ef4_probe_tx_queue(tx_queue);
 462                                         if (rc)
 463                                                 return rc;
 464                                 }
 465                                 if (!tx_queue->initialised)
 466                                         ef4_init_tx_queue(tx_queue);
 467                                 ef4_init_tx_queue_core_txq(tx_queue);
 468                         }
 469                 }
 470         } else {
 471                 /* Reduce number of classes before number of queues */
 472                 net_dev->num_tc = num_tc;
 473         }
 474
 475         rc = netif_set_real_num_tx_queues(net_dev,
 476                                           max_t(int, num_tc, 1) *
 477                                           efx->n_tx_channels);
 478         if (rc)
 479                 return rc;
 480
 481         /* Do not destroy high-priority queues when they become
 482          * unused.  We would have to flush them first, and it is
 483          * fairly difficult to flush a subset of TX queues.  Leave
 484          * it to ef4_fini_channels().
 485          */
 486
 487         net_dev->num_tc = num_tc;
 488         return 0;
 489 }
 490
 491 void ef4_xmit_done(struct ef4_tx_queue *tx_queue, unsigned int index)
 492 {
 493         unsigned fill_level;
 494         struct ef4_nic *efx = tx_queue->efx;
 495         struct ef4_tx_queue *txq2;
 496         unsigned int pkts_compl = 0, bytes_compl = 0;
 497
 498         EF4_BUG_ON_PARANOID(index > tx_queue->ptr_mask);
 499
 500         ef4_dequeue_buffers(tx_queue, index, &pkts_compl, &bytes_compl);
 501         tx_queue->pkts_compl += pkts_compl;
 502         tx_queue->bytes_compl += bytes_compl;
 503
 504         if (pkts_compl > 1)
 505                 ++tx_queue->merge_events;
 506
 507         /* See if we need to restart the netif queue.  This memory
 508          * barrier ensures that we write read_count (inside
 509          * ef4_dequeue_buffers()) before reading the queue status.
 510          */
 511         smp_mb();
 512         if (unlikely(netif_tx_queue_stopped(tx_queue->core_txq)) &&
 513             likely(efx->port_enabled) &&
 514             likely(netif_device_present(efx->net_dev))) {
 515                 txq2 = ef4_tx_queue_partner(tx_queue);
 516                 fill_level = max(tx_queue->insert_count - tx_queue->read_count,
 517                                  txq2->insert_count - txq2->read_count);
 518                 if (fill_level <= efx->txq_wake_thresh)
 519                         netif_tx_wake_queue(tx_queue->core_txq);
 520         }
 521
 522         /* Check whether the hardware queue is now empty */
 523         if ((int)(tx_queue->read_count - tx_queue->old_write_count) >= 0) {
 524                 tx_queue->old_write_count = ACCESS_ONCE(tx_queue->write_count);
 525                 if (tx_queue->read_count == tx_queue->old_write_count) {
 526                         smp_mb();
 527                         tx_queue->empty_read_count =
 528                                 tx_queue->read_count | EF4_EMPTY_COUNT_VALID;
 529                 }
 530         }
 531 }
 532
 533 static unsigned int ef4_tx_cb_page_count(struct ef4_tx_queue *tx_queue)
 534 {
 535         return DIV_ROUND_UP(tx_queue->ptr_mask + 1, PAGE_SIZE >> EF4_TX_CB_ORDER);
 536 }
 537
 538 int ef4_probe_tx_queue(struct ef4_tx_queue *tx_queue)
 539 {
 540         struct ef4_nic *efx = tx_queue->efx;
 541         unsigned int entries;
 542         int rc;
 543
 544         /* Create the smallest power-of-two aligned ring */
 545         entries = max(roundup_pow_of_two(efx->txq_entries), EF4_MIN_DMAQ_SIZE);
 546         EF4_BUG_ON_PARANOID(entries > EF4_MAX_DMAQ_SIZE);
 547         tx_queue->ptr_mask = entries - 1;
 548
 549         netif_dbg(efx, probe, efx->net_dev,
 550                   "creating TX queue %d size %#x mask %#x\n",
 551                   tx_queue->queue, efx->txq_entries, tx_queue->ptr_mask);
 552
 553         /* Allocate software ring */
 554         tx_queue->buffer = kcalloc(entries, sizeof(*tx_queue->buffer),
 555                                    GFP_KERNEL);
 556         if (!tx_queue->buffer)
 557                 return -ENOMEM;
 558
 559         tx_queue->cb_page = kcalloc(ef4_tx_cb_page_count(tx_queue),
 560                                     sizeof(tx_queue->cb_page[0]), GFP_KERNEL);
 561         if (!tx_queue->cb_page) {
 562                 rc = -ENOMEM;
 563                 goto fail1;
 564         }
 565
 566         /* Allocate hardware ring */
 567         rc = ef4_nic_probe_tx(tx_queue);
 568         if (rc)
 569                 goto fail2;
 570
 571         return 0;
 572
 573 fail2:
 574         kfree(tx_queue->cb_page);
 575         tx_queue->cb_page = NULL;
 576 fail1:
 577         kfree(tx_queue->buffer);
 578         tx_queue->buffer = NULL;
 579         return rc;
 580 }
 581
 582 void ef4_init_tx_queue(struct ef4_tx_queue *tx_queue)
 583 {
 584         struct ef4_nic *efx = tx_queue->efx;
 585
 586         netif_dbg(efx, drv, efx->net_dev,
 587                   "initialising TX queue %d\n", tx_queue->queue);
 588
 589         tx_queue->insert_count = 0;
 590         tx_queue->write_count = 0;
 591         tx_queue->old_write_count = 0;
 592         tx_queue->read_count = 0;
 593         tx_queue->old_read_count = 0;
 594         tx_queue->empty_read_count = 0 | EF4_EMPTY_COUNT_VALID;
 595         tx_queue->xmit_more_available = false;
 596
 597         /* Some older hardware requires Tx writes larger than 32. */
 598         tx_queue->tx_min_size = EF4_WORKAROUND_15592(efx) ? 33 : 0;
 599
 600         /* Set up TX descriptor ring */
 601         ef4_nic_init_tx(tx_queue);
 602
 603         tx_queue->initialised = true;
 604 }
 605
 606 void ef4_fini_tx_queue(struct ef4_tx_queue *tx_queue)
 607 {
 608         struct ef4_tx_buffer *buffer;
 609
 610         netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev,
 611                   "shutting down TX queue %d\n", tx_queue->queue);
 612
 613         if (!tx_queue->buffer)
 614                 return;
 615
 616         /* Free any buffers left in the ring */
 617         while (tx_queue->read_count != tx_queue->write_count) {
 618                 unsigned int pkts_compl = 0, bytes_compl = 0;
 619                 buffer = &tx_queue->buffer[tx_queue->read_count & tx_queue->ptr_mask];
 620                 ef4_dequeue_buffer(tx_queue, buffer, &pkts_compl, &bytes_compl);
 621
 622                 ++tx_queue->read_count;
 623         }
 624         tx_queue->xmit_more_available = false;
 625         netdev_tx_reset_queue(tx_queue->core_txq);
 626 }
 627
 628 void ef4_remove_tx_queue(struct ef4_tx_queue *tx_queue)
 629 {
 630         int i;
 631
 632         if (!tx_queue->buffer)
 633                 return;
 634
 635         netif_dbg(tx_queue->efx, drv, tx_queue->efx->net_dev,
 636                   "destroying TX queue %d\n", tx_queue->queue);
 637         ef4_nic_remove_tx(tx_queue);
 638
 639         if (tx_queue->cb_page) {
 640                 for (i = 0; i < ef4_tx_cb_page_count(tx_queue); i++)
 641                         ef4_nic_free_buffer(tx_queue->efx,
 642                                             &tx_queue->cb_page[i]);
 643                 kfree(tx_queue->cb_page);
 644                 tx_queue->cb_page = NULL;
 645         }
 646
 647         kfree(tx_queue->buffer);
 648         tx_queue->buffer = NULL;
 649 }