drivers/net/wireless/rt2x00/rt2x00queue.c

   1 /*
   2         Copyright (C) 2004 - 2008 rt2x00 SourceForge Project
   3         <http://rt2x00.serialmonkey.com>
   4
   5         This program is free software; you can redistribute it and/or modify
   6         it under the terms of the GNU General Public License as published by
   7         the Free Software Foundation; either version 2 of the License, or
   8         (at your option) any later version.
   9
  10         This program is distributed in the hope that it will be useful,
  11         but WITHOUT ANY WARRANTY; without even the implied warranty of
  12         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13         GNU General Public License for more details.
  14
  15         You should have received a copy of the GNU General Public License
  16         along with this program; if not, write to the
  17         Free Software Foundation, Inc.,
  18         59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  */
  20
  21 /*
  22         Module: rt2x00lib
  23         Abstract: rt2x00 queue specific routines.
  24  */
  25
  26 #include <linux/kernel.h>
  27 #include <linux/module.h>
  28 #include <linux/dma-mapping.h>
  29
  30 #include "rt2x00.h"
  31 #include "rt2x00lib.h"
  32
  33 struct sk_buff *rt2x00queue_alloc_rxskb(struct rt2x00_dev *rt2x00dev,
  34                                         struct queue_entry *entry)
  35 {
  36         unsigned int frame_size;
  37         unsigned int reserved_size;
  38         struct sk_buff *skb;
  39         struct skb_frame_desc *skbdesc;
  40
  41         /*
  42          * The frame size includes descriptor size, because the
  43          * hardware directly receive the frame into the skbuffer.
  44          */
  45         frame_size = entry->queue->data_size + entry->queue->desc_size;
  46
  47         /*
  48          * Reserve a few bytes extra headroom to allow drivers some moving
  49          * space (e.g. for alignment), while keeping the skb aligned.
  50          */
  51         reserved_size = 8;
  52
  53         /*
  54          * Allocate skbuffer.
  55          */
  56         skb = dev_alloc_skb(frame_size + reserved_size);
  57         if (!skb)
  58                 return NULL;
  59
  60         skb_reserve(skb, reserved_size);
  61         skb_put(skb, frame_size);
  62
  63         /*
  64          * Populate skbdesc.
  65          */
  66         skbdesc = get_skb_frame_desc(skb);
  67         memset(skbdesc, 0, sizeof(*skbdesc));
  68         skbdesc->entry = entry;
  69
  70         if (test_bit(DRIVER_REQUIRE_DMA, &rt2x00dev->flags)) {
  71                 skbdesc->skb_dma = dma_map_single(rt2x00dev->dev,
  72                                                   skb->data,
  73                                                   skb->len,
  74                                                   DMA_FROM_DEVICE);
  75                 skbdesc->flags |= SKBDESC_DMA_MAPPED_RX;
  76         }
  77
  78         return skb;
  79 }
  80
  81 void rt2x00queue_map_txskb(struct rt2x00_dev *rt2x00dev, struct sk_buff *skb)
  82 {
  83         struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
  84
  85         skbdesc->skb_dma = dma_map_single(rt2x00dev->dev, skb->data, skb->len,
  86                                           DMA_TO_DEVICE);
  87         skbdesc->flags |= SKBDESC_DMA_MAPPED_TX;
  88 }
  89 EXPORT_SYMBOL_GPL(rt2x00queue_map_txskb);
  90
  91 void rt2x00queue_unmap_skb(struct rt2x00_dev *rt2x00dev, struct sk_buff *skb)
  92 {
  93         struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
  94
  95         if (skbdesc->flags & SKBDESC_DMA_MAPPED_RX) {
  96                 dma_unmap_single(rt2x00dev->dev, skbdesc->skb_dma, skb->len,
  97                                  DMA_FROM_DEVICE);
  98                 skbdesc->flags &= ~SKBDESC_DMA_MAPPED_RX;
  99         }
 100
 101         if (skbdesc->flags & SKBDESC_DMA_MAPPED_TX) {
 102                 dma_unmap_single(rt2x00dev->dev, skbdesc->skb_dma, skb->len,
 103                                  DMA_TO_DEVICE);
 104                 skbdesc->flags &= ~SKBDESC_DMA_MAPPED_TX;
 105         }
 106 }
 107
 108 void rt2x00queue_free_skb(struct rt2x00_dev *rt2x00dev, struct sk_buff *skb)
 109 {
 110         rt2x00queue_unmap_skb(rt2x00dev, skb);
 111         dev_kfree_skb_any(skb);
 112 }
 113
 114 void rt2x00queue_create_tx_descriptor(struct queue_entry *entry,
 115                                       struct txentry_desc *txdesc)
 116 {
 117         struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;
 118         struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(entry->skb);
 119         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)entry->skb->data;
 120         struct ieee80211_rate *rate =
 121             ieee80211_get_tx_rate(rt2x00dev->hw, tx_info);
 122         const struct rt2x00_rate *hwrate;
 123         unsigned int data_length;
 124         unsigned int duration;
 125         unsigned int residual;
 126
 127         memset(txdesc, 0, sizeof(*txdesc));
 128
 129         /*
 130          * Initialize information from queue
 131          */
 132         txdesc->queue = entry->queue->qid;
 133         txdesc->cw_min = entry->queue->cw_min;
 134         txdesc->cw_max = entry->queue->cw_max;
 135         txdesc->aifs = entry->queue->aifs;
 136
 137         /* Data length should be extended with 4 bytes for CRC */
 138         data_length = entry->skb->len + 4;
 139
 140         /*
 141          * Check whether this frame is to be acked.
 142          */
 143         if (!(tx_info->flags & IEEE80211_TX_CTL_NO_ACK))
 144                 __set_bit(ENTRY_TXD_ACK, &txdesc->flags);
 145
 146         /*
 147          * Check if this is a RTS/CTS frame
 148          */
 149         if (ieee80211_is_rts(hdr->frame_control) ||
 150             ieee80211_is_cts(hdr->frame_control)) {
 151                 __set_bit(ENTRY_TXD_BURST, &txdesc->flags);
 152                 if (ieee80211_is_rts(hdr->frame_control))
 153                         __set_bit(ENTRY_TXD_RTS_FRAME, &txdesc->flags);
 154                 else
 155                         __set_bit(ENTRY_TXD_CTS_FRAME, &txdesc->flags);
 156                 if (tx_info->control.rts_cts_rate_idx >= 0)
 157                         rate =
 158                             ieee80211_get_rts_cts_rate(rt2x00dev->hw, tx_info);
 159         }
 160
 161         /*
 162          * Determine retry information.
 163          */
 164         txdesc->retry_limit = tx_info->control.retry_limit;
 165         if (tx_info->flags & IEEE80211_TX_CTL_LONG_RETRY_LIMIT)
 166                 __set_bit(ENTRY_TXD_RETRY_MODE, &txdesc->flags);
 167
 168         /*
 169          * Check if more fragments are pending
 170          */
 171         if (ieee80211_has_morefrags(hdr->frame_control)) {
 172                 __set_bit(ENTRY_TXD_BURST, &txdesc->flags);
 173                 __set_bit(ENTRY_TXD_MORE_FRAG, &txdesc->flags);
 174         }
 175
 176         /*
 177          * Beacons and probe responses require the tsf timestamp
 178          * to be inserted into the frame.
 179          */
 180         if (ieee80211_is_beacon(hdr->frame_control) ||
 181             ieee80211_is_probe_resp(hdr->frame_control))
 182                 __set_bit(ENTRY_TXD_REQ_TIMESTAMP, &txdesc->flags);
 183
 184         /*
 185          * Determine with what IFS priority this frame should be send.
 186          * Set ifs to IFS_SIFS when the this is not the first fragment,
 187          * or this fragment came after RTS/CTS.
 188          */
 189         if (test_bit(ENTRY_TXD_RTS_FRAME, &txdesc->flags)) {
 190                 txdesc->ifs = IFS_SIFS;
 191         } else if (tx_info->flags & IEEE80211_TX_CTL_FIRST_FRAGMENT) {
 192                 __set_bit(ENTRY_TXD_FIRST_FRAGMENT, &txdesc->flags);
 193                 txdesc->ifs = IFS_BACKOFF;
 194         } else {
 195                 txdesc->ifs = IFS_SIFS;
 196         }
 197
 198         /*
 199          * PLCP setup
 200          * Length calculation depends on OFDM/CCK rate.
 201          */
 202         hwrate = rt2x00_get_rate(rate->hw_value);
 203         txdesc->signal = hwrate->plcp;
 204         txdesc->service = 0x04;
 205
 206         if (hwrate->flags & DEV_RATE_OFDM) {
 207                 __set_bit(ENTRY_TXD_OFDM_RATE, &txdesc->flags);
 208
 209                 txdesc->length_high = (data_length >> 6) & 0x3f;
 210                 txdesc->length_low = data_length & 0x3f;
 211         } else {
 212                 /*
 213                  * Convert length to microseconds.
 214                  */
 215                 residual = get_duration_res(data_length, hwrate->bitrate);
 216                 duration = get_duration(data_length, hwrate->bitrate);
 217
 218                 if (residual != 0) {
 219                         duration++;
 220
 221                         /*
 222                          * Check if we need to set the Length Extension
 223                          */
 224                         if (hwrate->bitrate == 110 && residual <= 30)
 225                                 txdesc->service |= 0x80;
 226                 }
 227
 228                 txdesc->length_high = (duration >> 8) & 0xff;
 229                 txdesc->length_low = duration & 0xff;
 230
 231                 /*
 232                  * When preamble is enabled we should set the
 233                  * preamble bit for the signal.
 234                  */
 235                 if (rt2x00_get_rate_preamble(rate->hw_value))
 236                         txdesc->signal |= 0x08;
 237         }
 238 }
 239 EXPORT_SYMBOL_GPL(rt2x00queue_create_tx_descriptor);
 240
 241 void rt2x00queue_write_tx_descriptor(struct queue_entry *entry,
 242                                      struct txentry_desc *txdesc)
 243 {
 244         struct data_queue *queue = entry->queue;
 245         struct rt2x00_dev *rt2x00dev = queue->rt2x00dev;
 246
 247         rt2x00dev->ops->lib->write_tx_desc(rt2x00dev, entry->skb, txdesc);
 248
 249         /*
 250          * All processing on the frame has been completed, this means
 251          * it is now ready to be dumped to userspace through debugfs.
 252          */
 253         rt2x00debug_dump_frame(rt2x00dev, DUMP_FRAME_TX, entry->skb);
 254
 255         /*
 256          * Check if we need to kick the queue, there are however a few rules
 257          *      1) Don't kick beacon queue
 258          *      2) Don't kick unless this is the last in frame in a burst.
 259          *         When the burst flag is set, this frame is always followed
 260          *         by another frame which in some way are related to eachother.
 261          *         This is true for fragments, RTS or CTS-to-self frames.
 262          *      3) Rule 2 can be broken when the available entries
 263          *         in the queue are less then a certain threshold.
 264          */
 265         if (entry->queue->qid == QID_BEACON)
 266                 return;
 267
 268         if (rt2x00queue_threshold(queue) ||
 269             !test_bit(ENTRY_TXD_BURST, &txdesc->flags))
 270                 rt2x00dev->ops->lib->kick_tx_queue(rt2x00dev, queue->qid);
 271 }
 272 EXPORT_SYMBOL_GPL(rt2x00queue_write_tx_descriptor);
 273
 274 int rt2x00queue_write_tx_frame(struct data_queue *queue, struct sk_buff *skb)
 275 {
 276         struct queue_entry *entry = rt2x00queue_get_entry(queue, Q_INDEX);
 277         struct txentry_desc txdesc;
 278         struct skb_frame_desc *skbdesc;
 279
 280         if (unlikely(rt2x00queue_full(queue)))
 281                 return -EINVAL;
 282
 283         if (__test_and_set_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags)) {
 284                 ERROR(queue->rt2x00dev,
 285                       "Arrived at non-free entry in the non-full queue %d.\n"
 286                       "Please file bug report to %s.\n",
 287                       queue->qid, DRV_PROJECT);
 288                 return -EINVAL;
 289         }
 290
 291         /*
 292          * Copy all TX descriptor information into txdesc,
 293          * after that we are free to use the skb->cb array
 294          * for our information.
 295          */
 296         entry->skb = skb;
 297         rt2x00queue_create_tx_descriptor(entry, &txdesc);
 298
 299         /*
 300          * skb->cb array is now ours and we are free to use it.
 301          */
 302         skbdesc = get_skb_frame_desc(entry->skb);
 303         memset(skbdesc, 0, sizeof(*skbdesc));
 304         skbdesc->entry = entry;
 305
 306         if (unlikely(queue->rt2x00dev->ops->lib->write_tx_data(entry))) {
 307                 __clear_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags);
 308                 return -EIO;
 309         }
 310
 311         if (test_bit(DRIVER_REQUIRE_DMA, &queue->rt2x00dev->flags))
 312                 rt2x00queue_map_txskb(queue->rt2x00dev, skb);
 313
 314         __set_bit(ENTRY_DATA_PENDING, &entry->flags);
 315
 316         rt2x00queue_index_inc(queue, Q_INDEX);
 317         rt2x00queue_write_tx_descriptor(entry, &txdesc);
 318
 319         return 0;
 320 }
 321
 322 struct data_queue *rt2x00queue_get_queue(struct rt2x00_dev *rt2x00dev,
 323                                          const enum data_queue_qid queue)
 324 {
 325         int atim = test_bit(DRIVER_REQUIRE_ATIM_QUEUE, &rt2x00dev->flags);
 326
 327         if (queue < rt2x00dev->ops->tx_queues && rt2x00dev->tx)
 328                 return &rt2x00dev->tx[queue];
 329
 330         if (!rt2x00dev->bcn)
 331                 return NULL;
 332
 333         if (queue == QID_BEACON)
 334                 return &rt2x00dev->bcn[0];
 335         else if (queue == QID_ATIM && atim)
 336                 return &rt2x00dev->bcn[1];
 337
 338         return NULL;
 339 }
 340 EXPORT_SYMBOL_GPL(rt2x00queue_get_queue);
 341
 342 struct queue_entry *rt2x00queue_get_entry(struct data_queue *queue,
 343                                           enum queue_index index)
 344 {
 345         struct queue_entry *entry;
 346         unsigned long irqflags;
 347
 348         if (unlikely(index >= Q_INDEX_MAX)) {
 349                 ERROR(queue->rt2x00dev,
 350                       "Entry requested from invalid index type (%d)\n", index);
 351                 return NULL;
 352         }
 353
 354         spin_lock_irqsave(&queue->lock, irqflags);
 355
 356         entry = &queue->entries[queue->index[index]];
 357
 358         spin_unlock_irqrestore(&queue->lock, irqflags);
 359
 360         return entry;
 361 }
 362 EXPORT_SYMBOL_GPL(rt2x00queue_get_entry);
 363
 364 void rt2x00queue_index_inc(struct data_queue *queue, enum queue_index index)
 365 {
 366         unsigned long irqflags;
 367
 368         if (unlikely(index >= Q_INDEX_MAX)) {
 369                 ERROR(queue->rt2x00dev,
 370                       "Index change on invalid index type (%d)\n", index);
 371                 return;
 372         }
 373
 374         spin_lock_irqsave(&queue->lock, irqflags);
 375
 376         queue->index[index]++;
 377         if (queue->index[index] >= queue->limit)
 378                 queue->index[index] = 0;
 379
 380         if (index == Q_INDEX) {
 381                 queue->length++;
 382         } else if (index == Q_INDEX_DONE) {
 383                 queue->length--;
 384                 queue->count ++;
 385         }
 386
 387         spin_unlock_irqrestore(&queue->lock, irqflags);
 388 }
 389
 390 static void rt2x00queue_reset(struct data_queue *queue)
 391 {
 392         unsigned long irqflags;
 393
 394         spin_lock_irqsave(&queue->lock, irqflags);
 395
 396         queue->count = 0;
 397         queue->length = 0;
 398         memset(queue->index, 0, sizeof(queue->index));
 399
 400         spin_unlock_irqrestore(&queue->lock, irqflags);
 401 }
 402
 403 void rt2x00queue_init_rx(struct rt2x00_dev *rt2x00dev)
 404 {
 405         struct data_queue *queue = rt2x00dev->rx;
 406         unsigned int i;
 407
 408         rt2x00queue_reset(queue);
 409
 410         if (!rt2x00dev->ops->lib->init_rxentry)
 411                 return;
 412
 413         for (i = 0; i < queue->limit; i++)
 414                 rt2x00dev->ops->lib->init_rxentry(rt2x00dev,
 415                                                   &queue->entries[i]);
 416 }
 417
 418 void rt2x00queue_init_tx(struct rt2x00_dev *rt2x00dev)
 419 {
 420         struct data_queue *queue;
 421         unsigned int i;
 422
 423         txall_queue_for_each(rt2x00dev, queue) {
 424                 rt2x00queue_reset(queue);
 425
 426                 if (!rt2x00dev->ops->lib->init_txentry)
 427                         continue;
 428
 429                 for (i = 0; i < queue->limit; i++)
 430                         rt2x00dev->ops->lib->init_txentry(rt2x00dev,
 431                                                           &queue->entries[i]);
 432         }
 433 }
 434
 435 static int rt2x00queue_alloc_entries(struct data_queue *queue,
 436                                      const struct data_queue_desc *qdesc)
 437 {
 438         struct queue_entry *entries;
 439         unsigned int entry_size;
 440         unsigned int i;
 441
 442         rt2x00queue_reset(queue);
 443
 444         queue->limit = qdesc->entry_num;
 445         queue->threshold = DIV_ROUND_UP(qdesc->entry_num, 10);
 446         queue->data_size = qdesc->data_size;
 447         queue->desc_size = qdesc->desc_size;
 448
 449         /*
 450          * Allocate all queue entries.
 451          */
 452         entry_size = sizeof(*entries) + qdesc->priv_size;
 453         entries = kzalloc(queue->limit * entry_size, GFP_KERNEL);
 454         if (!entries)
 455                 return -ENOMEM;
 456
 457 #define QUEUE_ENTRY_PRIV_OFFSET(__base, __index, __limit, __esize, __psize) \
 458         ( ((char *)(__base)) + ((__limit) * (__esize)) + \
 459             ((__index) * (__psize)) )
 460
 461         for (i = 0; i < queue->limit; i++) {
 462                 entries[i].flags = 0;
 463                 entries[i].queue = queue;
 464                 entries[i].skb = NULL;
 465                 entries[i].entry_idx = i;
 466                 entries[i].priv_data =
 467                     QUEUE_ENTRY_PRIV_OFFSET(entries, i, queue->limit,
 468                                             sizeof(*entries), qdesc->priv_size);
 469         }
 470
 471 #undef QUEUE_ENTRY_PRIV_OFFSET
 472
 473         queue->entries = entries;
 474
 475         return 0;
 476 }
 477
 478 static void rt2x00queue_free_skbs(struct rt2x00_dev *rt2x00dev,
 479                                   struct data_queue *queue)
 480 {
 481         unsigned int i;
 482
 483         if (!queue->entries)
 484                 return;
 485
 486         for (i = 0; i < queue->limit; i++) {
 487                 if (queue->entries[i].skb)
 488                         rt2x00queue_free_skb(rt2x00dev, queue->entries[i].skb);
 489         }
 490 }
 491
 492 static int rt2x00queue_alloc_rxskbs(struct rt2x00_dev *rt2x00dev,
 493                                     struct data_queue *queue)
 494 {
 495         unsigned int i;
 496         struct sk_buff *skb;
 497
 498         for (i = 0; i < queue->limit; i++) {
 499                 skb = rt2x00queue_alloc_rxskb(rt2x00dev, &queue->entries[i]);
 500                 if (!skb)
 501                         return -ENOMEM;
 502                 queue->entries[i].skb = skb;
 503         }
 504
 505         return 0;
 506 }
 507
 508 int rt2x00queue_initialize(struct rt2x00_dev *rt2x00dev)
 509 {
 510         struct data_queue *queue;
 511         int status;
 512
 513         status = rt2x00queue_alloc_entries(rt2x00dev->rx, rt2x00dev->ops->rx);
 514         if (status)
 515                 goto exit;
 516
 517         tx_queue_for_each(rt2x00dev, queue) {
 518                 status = rt2x00queue_alloc_entries(queue, rt2x00dev->ops->tx);
 519                 if (status)
 520                         goto exit;
 521         }
 522
 523         status = rt2x00queue_alloc_entries(rt2x00dev->bcn, rt2x00dev->ops->bcn);
 524         if (status)
 525                 goto exit;
 526
 527         if (test_bit(DRIVER_REQUIRE_ATIM_QUEUE, &rt2x00dev->flags)) {
 528                 status = rt2x00queue_alloc_entries(&rt2x00dev->bcn[1],
 529                                                    rt2x00dev->ops->atim);
 530                 if (status)
 531                         goto exit;
 532         }
 533
 534         status = rt2x00queue_alloc_rxskbs(rt2x00dev, rt2x00dev->rx);
 535         if (status)
 536                 goto exit;
 537
 538         return 0;
 539
 540 exit:
 541         ERROR(rt2x00dev, "Queue entries allocation failed.\n");
 542
 543         rt2x00queue_uninitialize(rt2x00dev);
 544
 545         return status;
 546 }
 547
 548 void rt2x00queue_uninitialize(struct rt2x00_dev *rt2x00dev)
 549 {
 550         struct data_queue *queue;
 551
 552         rt2x00queue_free_skbs(rt2x00dev, rt2x00dev->rx);
 553
 554         queue_for_each(rt2x00dev, queue) {
 555                 kfree(queue->entries);
 556                 queue->entries = NULL;
 557         }
 558 }
 559
 560 static void rt2x00queue_init(struct rt2x00_dev *rt2x00dev,
 561                              struct data_queue *queue, enum data_queue_qid qid)
 562 {
 563         spin_lock_init(&queue->lock);
 564
 565         queue->rt2x00dev = rt2x00dev;
 566         queue->qid = qid;
 567         queue->aifs = 2;
 568         queue->cw_min = 5;
 569         queue->cw_max = 10;
 570 }
 571
 572 int rt2x00queue_allocate(struct rt2x00_dev *rt2x00dev)
 573 {
 574         struct data_queue *queue;
 575         enum data_queue_qid qid;
 576         unsigned int req_atim =
 577             !!test_bit(DRIVER_REQUIRE_ATIM_QUEUE, &rt2x00dev->flags);
 578
 579         /*
 580          * We need the following queues:
 581          * RX: 1
 582          * TX: ops->tx_queues
 583          * Beacon: 1
 584          * Atim: 1 (if required)
 585          */
 586         rt2x00dev->data_queues = 2 + rt2x00dev->ops->tx_queues + req_atim;
 587
 588         queue = kzalloc(rt2x00dev->data_queues * sizeof(*queue), GFP_KERNEL);
 589         if (!queue) {
 590                 ERROR(rt2x00dev, "Queue allocation failed.\n");
 591                 return -ENOMEM;
 592         }
 593
 594         /*
 595          * Initialize pointers
 596          */
 597         rt2x00dev->rx = queue;
 598         rt2x00dev->tx = &queue[1];
 599         rt2x00dev->bcn = &queue[1 + rt2x00dev->ops->tx_queues];
 600
 601         /*
 602          * Initialize queue parameters.
 603          * RX: qid = QID_RX
 604          * TX: qid = QID_AC_BE + index
 605          * TX: cw_min: 2^5 = 32.
 606          * TX: cw_max: 2^10 = 1024.
 607          * BCN: qid = QID_BEACON
 608          * ATIM: qid = QID_ATIM
 609          */
 610         rt2x00queue_init(rt2x00dev, rt2x00dev->rx, QID_RX);
 611
 612         qid = QID_AC_BE;
 613         tx_queue_for_each(rt2x00dev, queue)
 614                 rt2x00queue_init(rt2x00dev, queue, qid++);
 615
 616         rt2x00queue_init(rt2x00dev, &rt2x00dev->bcn[0], QID_BEACON);
 617         if (req_atim)
 618                 rt2x00queue_init(rt2x00dev, &rt2x00dev->bcn[1], QID_ATIM);
 619
 620         return 0;
 621 }
 622
 623 void rt2x00queue_free(struct rt2x00_dev *rt2x00dev)
 624 {
 625         kfree(rt2x00dev->rx);
 626         rt2x00dev->rx = NULL;
 627         rt2x00dev->tx = NULL;
 628         rt2x00dev->bcn = NULL;
 629 }