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   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
  29 #include "rt2x00.h"
  30 #include "rt2x00lib.h"
  31
  32 struct sk_buff *rt2x00queue_alloc_skb(struct data_queue *queue)
  33 {
  34         struct sk_buff *skb;
  35         unsigned int frame_size;
  36         unsigned int reserved_size;
  37
  38         /*
  39          * The frame size includes descriptor size, because the
  40          * hardware directly receive the frame into the skbuffer.
  41          */
  42         frame_size = queue->data_size + queue->desc_size;
  43
  44         /*
  45          * Reserve a few bytes extra headroom to allow drivers some moving
  46          * space (e.g. for alignment), while keeping the skb aligned.
  47          */
  48         reserved_size = 8;
  49
  50         /*
  51          * Allocate skbuffer.
  52          */
  53         skb = dev_alloc_skb(frame_size + reserved_size);
  54         if (!skb)
  55                 return NULL;
  56
  57         skb_reserve(skb, reserved_size);
  58         skb_put(skb, frame_size);
  59
  60         return skb;
  61 }
  62 EXPORT_SYMBOL_GPL(rt2x00queue_alloc_skb);
  63
  64 void rt2x00queue_free_skb(struct sk_buff *skb)
  65 {
  66         dev_kfree_skb_any(skb);
  67 }
  68 EXPORT_SYMBOL_GPL(rt2x00queue_free_skb);
  69
  70 void rt2x00queue_create_tx_descriptor(struct queue_entry *entry,
  71                                       struct txentry_desc *txdesc)
  72 {
  73         struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;
  74         struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(entry->skb);
  75         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)entry->skb->data;
  76         struct ieee80211_rate *rate =
  77             ieee80211_get_tx_rate(rt2x00dev->hw, tx_info);
  78         const struct rt2x00_rate *hwrate;
  79         unsigned int data_length;
  80         unsigned int duration;
  81         unsigned int residual;
  82
  83         memset(txdesc, 0, sizeof(*txdesc));
  84
  85         /*
  86          * Initialize information from queue
  87          */
  88         txdesc->queue = entry->queue->qid;
  89         txdesc->cw_min = entry->queue->cw_min;
  90         txdesc->cw_max = entry->queue->cw_max;
  91         txdesc->aifs = entry->queue->aifs;
  92
  93         /* Data length should be extended with 4 bytes for CRC */
  94         data_length = entry->skb->len + 4;
  95
  96         /*
  97          * Check whether this frame is to be acked.
  98          */
  99         if (!(tx_info->flags & IEEE80211_TX_CTL_NO_ACK))
 100                 __set_bit(ENTRY_TXD_ACK, &txdesc->flags);
 101
 102         /*
 103          * Check if this is a RTS/CTS frame
 104          */
 105         if (ieee80211_is_rts(hdr->frame_control) ||
 106             ieee80211_is_cts(hdr->frame_control)) {
 107                 __set_bit(ENTRY_TXD_BURST, &txdesc->flags);
 108                 if (ieee80211_is_rts(hdr->frame_control))
 109                         __set_bit(ENTRY_TXD_RTS_FRAME, &txdesc->flags);
 110                 else
 111                         __set_bit(ENTRY_TXD_CTS_FRAME, &txdesc->flags);
 112                 if (tx_info->control.rts_cts_rate_idx >= 0)
 113                         rate =
 114                             ieee80211_get_rts_cts_rate(rt2x00dev->hw, tx_info);
 115         }
 116
 117         /*
 118          * Determine retry information.
 119          */
 120         txdesc->retry_limit = tx_info->control.retry_limit;
 121         if (tx_info->flags & IEEE80211_TX_CTL_LONG_RETRY_LIMIT)
 122                 __set_bit(ENTRY_TXD_RETRY_MODE, &txdesc->flags);
 123
 124         /*
 125          * Check if more fragments are pending
 126          */
 127         if (ieee80211_has_morefrags(hdr->frame_control)) {
 128                 __set_bit(ENTRY_TXD_BURST, &txdesc->flags);
 129                 __set_bit(ENTRY_TXD_MORE_FRAG, &txdesc->flags);
 130         }
 131
 132         /*
 133          * Beacons and probe responses require the tsf timestamp
 134          * to be inserted into the frame.
 135          */
 136         if (ieee80211_is_beacon(hdr->frame_control) ||
 137             ieee80211_is_probe_resp(hdr->frame_control))
 138                 __set_bit(ENTRY_TXD_REQ_TIMESTAMP, &txdesc->flags);
 139
 140         /*
 141          * Determine with what IFS priority this frame should be send.
 142          * Set ifs to IFS_SIFS when the this is not the first fragment,
 143          * or this fragment came after RTS/CTS.
 144          */
 145         if (test_bit(ENTRY_TXD_RTS_FRAME, &txdesc->flags)) {
 146                 txdesc->ifs = IFS_SIFS;
 147         } else if (tx_info->flags & IEEE80211_TX_CTL_FIRST_FRAGMENT) {
 148                 __set_bit(ENTRY_TXD_FIRST_FRAGMENT, &txdesc->flags);
 149                 txdesc->ifs = IFS_BACKOFF;
 150         } else {
 151                 txdesc->ifs = IFS_SIFS;
 152         }
 153
 154         /*
 155          * PLCP setup
 156          * Length calculation depends on OFDM/CCK rate.
 157          */
 158         hwrate = rt2x00_get_rate(rate->hw_value);
 159         txdesc->signal = hwrate->plcp;
 160         txdesc->service = 0x04;
 161
 162         if (hwrate->flags & DEV_RATE_OFDM) {
 163                 __set_bit(ENTRY_TXD_OFDM_RATE, &txdesc->flags);
 164
 165                 txdesc->length_high = (data_length >> 6) & 0x3f;
 166                 txdesc->length_low = data_length & 0x3f;
 167         } else {
 168                 /*
 169                  * Convert length to microseconds.
 170                  */
 171                 residual = get_duration_res(data_length, hwrate->bitrate);
 172                 duration = get_duration(data_length, hwrate->bitrate);
 173
 174                 if (residual != 0) {
 175                         duration++;
 176
 177                         /*
 178                          * Check if we need to set the Length Extension
 179                          */
 180                         if (hwrate->bitrate == 110 && residual <= 30)
 181                                 txdesc->service |= 0x80;
 182                 }
 183
 184                 txdesc->length_high = (duration >> 8) & 0xff;
 185                 txdesc->length_low = duration & 0xff;
 186
 187                 /*
 188                  * When preamble is enabled we should set the
 189                  * preamble bit for the signal.
 190                  */
 191                 if (rt2x00_get_rate_preamble(rate->hw_value))
 192                         txdesc->signal |= 0x08;
 193         }
 194 }
 195 EXPORT_SYMBOL_GPL(rt2x00queue_create_tx_descriptor);
 196
 197 void rt2x00queue_write_tx_descriptor(struct queue_entry *entry,
 198                                      struct txentry_desc *txdesc)
 199 {
 200         struct data_queue *queue = entry->queue;
 201         struct rt2x00_dev *rt2x00dev = queue->rt2x00dev;
 202
 203         rt2x00dev->ops->lib->write_tx_desc(rt2x00dev, entry->skb, txdesc);
 204
 205         /*
 206          * All processing on the frame has been completed, this means
 207          * it is now ready to be dumped to userspace through debugfs.
 208          */
 209         rt2x00debug_dump_frame(rt2x00dev, DUMP_FRAME_TX, entry->skb);
 210
 211         /*
 212          * Check if we need to kick the queue, there are however a few rules
 213          *      1) Don't kick beacon queue
 214          *      2) Don't kick unless this is the last in frame in a burst.
 215          *         When the burst flag is set, this frame is always followed
 216          *         by another frame which in some way are related to eachother.
 217          *         This is true for fragments, RTS or CTS-to-self frames.
 218          *      3) Rule 2 can be broken when the available entries
 219          *         in the queue are less then a certain threshold.
 220          */
 221         if (entry->queue->qid == QID_BEACON)
 222                 return;
 223
 224         if (rt2x00queue_threshold(queue) ||
 225             !test_bit(ENTRY_TXD_BURST, &txdesc->flags))
 226                 rt2x00dev->ops->lib->kick_tx_queue(rt2x00dev, queue->qid);
 227 }
 228 EXPORT_SYMBOL_GPL(rt2x00queue_write_tx_descriptor);
 229
 230 int rt2x00queue_write_tx_frame(struct data_queue *queue, struct sk_buff *skb)
 231 {
 232         struct queue_entry *entry = rt2x00queue_get_entry(queue, Q_INDEX);
 233         struct txentry_desc txdesc;
 234
 235         if (unlikely(rt2x00queue_full(queue)))
 236                 return -EINVAL;
 237
 238         if (__test_and_set_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags)) {
 239                 ERROR(queue->rt2x00dev,
 240                       "Arrived at non-free entry in the non-full queue %d.\n"
 241                       "Please file bug report to %s.\n",
 242                       queue->qid, DRV_PROJECT);
 243                 return -EINVAL;
 244         }
 245
 246         /*
 247          * Copy all TX descriptor information into txdesc,
 248          * after that we are free to use the skb->cb array
 249          * for our information.
 250          */
 251         entry->skb = skb;
 252         rt2x00queue_create_tx_descriptor(entry, &txdesc);
 253
 254         if (unlikely(queue->rt2x00dev->ops->lib->write_tx_data(entry))) {
 255                 __clear_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags);
 256                 return -EIO;
 257         }
 258
 259         __set_bit(ENTRY_DATA_PENDING, &entry->flags);
 260
 261         rt2x00queue_index_inc(queue, Q_INDEX);
 262         rt2x00queue_write_tx_descriptor(entry, &txdesc);
 263
 264         return 0;
 265 }
 266
 267 struct data_queue *rt2x00queue_get_queue(struct rt2x00_dev *rt2x00dev,
 268                                          const enum data_queue_qid queue)
 269 {
 270         int atim = test_bit(DRIVER_REQUIRE_ATIM_QUEUE, &rt2x00dev->flags);
 271
 272         if (queue < rt2x00dev->ops->tx_queues && rt2x00dev->tx)
 273                 return &rt2x00dev->tx[queue];
 274
 275         if (!rt2x00dev->bcn)
 276                 return NULL;
 277
 278         if (queue == QID_BEACON)
 279                 return &rt2x00dev->bcn[0];
 280         else if (queue == QID_ATIM && atim)
 281                 return &rt2x00dev->bcn[1];
 282
 283         return NULL;
 284 }
 285 EXPORT_SYMBOL_GPL(rt2x00queue_get_queue);
 286
 287 struct queue_entry *rt2x00queue_get_entry(struct data_queue *queue,
 288                                           enum queue_index index)
 289 {
 290         struct queue_entry *entry;
 291         unsigned long irqflags;
 292
 293         if (unlikely(index >= Q_INDEX_MAX)) {
 294                 ERROR(queue->rt2x00dev,
 295                       "Entry requested from invalid index type (%d)\n", index);
 296                 return NULL;
 297         }
 298
 299         spin_lock_irqsave(&queue->lock, irqflags);
 300
 301         entry = &queue->entries[queue->index[index]];
 302
 303         spin_unlock_irqrestore(&queue->lock, irqflags);
 304
 305         return entry;
 306 }
 307 EXPORT_SYMBOL_GPL(rt2x00queue_get_entry);
 308
 309 void rt2x00queue_index_inc(struct data_queue *queue, enum queue_index index)
 310 {
 311         unsigned long irqflags;
 312
 313         if (unlikely(index >= Q_INDEX_MAX)) {
 314                 ERROR(queue->rt2x00dev,
 315                       "Index change on invalid index type (%d)\n", index);
 316                 return;
 317         }
 318
 319         spin_lock_irqsave(&queue->lock, irqflags);
 320
 321         queue->index[index]++;
 322         if (queue->index[index] >= queue->limit)
 323                 queue->index[index] = 0;
 324
 325         if (index == Q_INDEX) {
 326                 queue->length++;
 327         } else if (index == Q_INDEX_DONE) {
 328                 queue->length--;
 329                 queue->count ++;
 330         }
 331
 332         spin_unlock_irqrestore(&queue->lock, irqflags);
 333 }
 334 EXPORT_SYMBOL_GPL(rt2x00queue_index_inc);
 335
 336 static void rt2x00queue_reset(struct data_queue *queue)
 337 {
 338         unsigned long irqflags;
 339
 340         spin_lock_irqsave(&queue->lock, irqflags);
 341
 342         queue->count = 0;
 343         queue->length = 0;
 344         memset(queue->index, 0, sizeof(queue->index));
 345
 346         spin_unlock_irqrestore(&queue->lock, irqflags);
 347 }
 348
 349 void rt2x00queue_init_rx(struct rt2x00_dev *rt2x00dev)
 350 {
 351         struct data_queue *queue = rt2x00dev->rx;
 352         unsigned int i;
 353
 354         rt2x00queue_reset(queue);
 355
 356         if (!rt2x00dev->ops->lib->init_rxentry)
 357                 return;
 358
 359         for (i = 0; i < queue->limit; i++)
 360                 rt2x00dev->ops->lib->init_rxentry(rt2x00dev,
 361                                                   &queue->entries[i]);
 362 }
 363
 364 void rt2x00queue_init_tx(struct rt2x00_dev *rt2x00dev)
 365 {
 366         struct data_queue *queue;
 367         unsigned int i;
 368
 369         txall_queue_for_each(rt2x00dev, queue) {
 370                 rt2x00queue_reset(queue);
 371
 372                 if (!rt2x00dev->ops->lib->init_txentry)
 373                         continue;
 374
 375                 for (i = 0; i < queue->limit; i++)
 376                         rt2x00dev->ops->lib->init_txentry(rt2x00dev,
 377                                                           &queue->entries[i]);
 378         }
 379 }
 380
 381 static int rt2x00queue_alloc_entries(struct data_queue *queue,
 382                                      const struct data_queue_desc *qdesc)
 383 {
 384         struct queue_entry *entries;
 385         unsigned int entry_size;
 386         unsigned int i;
 387
 388         rt2x00queue_reset(queue);
 389
 390         queue->limit = qdesc->entry_num;
 391         queue->threshold = DIV_ROUND_UP(qdesc->entry_num, 10);
 392         queue->data_size = qdesc->data_size;
 393         queue->desc_size = qdesc->desc_size;
 394
 395         /*
 396          * Allocate all queue entries.
 397          */
 398         entry_size = sizeof(*entries) + qdesc->priv_size;
 399         entries = kzalloc(queue->limit * entry_size, GFP_KERNEL);
 400         if (!entries)
 401                 return -ENOMEM;
 402
 403 #define QUEUE_ENTRY_PRIV_OFFSET(__base, __index, __limit, __esize, __psize) \
 404         ( ((char *)(__base)) + ((__limit) * (__esize)) + \
 405             ((__index) * (__psize)) )
 406
 407         for (i = 0; i < queue->limit; i++) {
 408                 entries[i].flags = 0;
 409                 entries[i].queue = queue;
 410                 entries[i].skb = NULL;
 411                 entries[i].entry_idx = i;
 412                 entries[i].priv_data =
 413                     QUEUE_ENTRY_PRIV_OFFSET(entries, i, queue->limit,
 414                                             sizeof(*entries), qdesc->priv_size);
 415         }
 416
 417 #undef QUEUE_ENTRY_PRIV_OFFSET
 418
 419         queue->entries = entries;
 420
 421         return 0;
 422 }
 423
 424 static void rt2x00queue_free_skbs(struct data_queue *queue)
 425 {
 426         unsigned int i;
 427
 428         if (!queue->entries)
 429                 return;
 430
 431         for (i = 0; i < queue->limit; i++) {
 432                 if (queue->entries[i].skb)
 433                         rt2x00queue_free_skb(queue->entries[i].skb);
 434         }
 435 }
 436
 437 static int rt2x00queue_alloc_skbs(struct data_queue *queue)
 438 {
 439         unsigned int i;
 440         struct sk_buff *skb;
 441
 442         for (i = 0; i < queue->limit; i++) {
 443                 skb = rt2x00queue_alloc_skb(queue);
 444                 if (!skb)
 445                         goto exit;
 446
 447                 queue->entries[i].skb = skb;
 448         }
 449
 450         return 0;
 451
 452 exit:
 453         rt2x00queue_free_skbs(queue);
 454
 455         return -ENOMEM;
 456 }
 457
 458 int rt2x00queue_initialize(struct rt2x00_dev *rt2x00dev)
 459 {
 460         struct data_queue *queue;
 461         int status;
 462
 463         status = rt2x00queue_alloc_entries(rt2x00dev->rx, rt2x00dev->ops->rx);
 464         if (status)
 465                 goto exit;
 466
 467         tx_queue_for_each(rt2x00dev, queue) {
 468                 status = rt2x00queue_alloc_entries(queue, rt2x00dev->ops->tx);
 469                 if (status)
 470                         goto exit;
 471         }
 472
 473         status = rt2x00queue_alloc_entries(rt2x00dev->bcn, rt2x00dev->ops->bcn);
 474         if (status)
 475                 goto exit;
 476
 477         if (test_bit(DRIVER_REQUIRE_ATIM_QUEUE, &rt2x00dev->flags)) {
 478                 status = rt2x00queue_alloc_entries(&rt2x00dev->bcn[1],
 479                                                    rt2x00dev->ops->atim);
 480                 if (status)
 481                         goto exit;
 482         }
 483
 484         status = rt2x00queue_alloc_skbs(rt2x00dev->rx);
 485         if (status)
 486                 goto exit;
 487
 488         return 0;
 489
 490 exit:
 491         ERROR(rt2x00dev, "Queue entries allocation failed.\n");
 492
 493         rt2x00queue_uninitialize(rt2x00dev);
 494
 495         return status;
 496 }
 497
 498 void rt2x00queue_uninitialize(struct rt2x00_dev *rt2x00dev)
 499 {
 500         struct data_queue *queue;
 501
 502         rt2x00queue_free_skbs(rt2x00dev->rx);
 503
 504         queue_for_each(rt2x00dev, queue) {
 505                 kfree(queue->entries);
 506                 queue->entries = NULL;
 507         }
 508 }
 509
 510 static void rt2x00queue_init(struct rt2x00_dev *rt2x00dev,
 511                              struct data_queue *queue, enum data_queue_qid qid)
 512 {
 513         spin_lock_init(&queue->lock);
 514
 515         queue->rt2x00dev = rt2x00dev;
 516         queue->qid = qid;
 517         queue->aifs = 2;
 518         queue->cw_min = 5;
 519         queue->cw_max = 10;
 520 }
 521
 522 int rt2x00queue_allocate(struct rt2x00_dev *rt2x00dev)
 523 {
 524         struct data_queue *queue;
 525         enum data_queue_qid qid;
 526         unsigned int req_atim =
 527             !!test_bit(DRIVER_REQUIRE_ATIM_QUEUE, &rt2x00dev->flags);
 528
 529         /*
 530          * We need the following queues:
 531          * RX: 1
 532          * TX: ops->tx_queues
 533          * Beacon: 1
 534          * Atim: 1 (if required)
 535          */
 536         rt2x00dev->data_queues = 2 + rt2x00dev->ops->tx_queues + req_atim;
 537
 538         queue = kzalloc(rt2x00dev->data_queues * sizeof(*queue), GFP_KERNEL);
 539         if (!queue) {
 540                 ERROR(rt2x00dev, "Queue allocation failed.\n");
 541                 return -ENOMEM;
 542         }
 543
 544         /*
 545          * Initialize pointers
 546          */
 547         rt2x00dev->rx = queue;
 548         rt2x00dev->tx = &queue[1];
 549         rt2x00dev->bcn = &queue[1 + rt2x00dev->ops->tx_queues];
 550
 551         /*
 552          * Initialize queue parameters.
 553          * RX: qid = QID_RX
 554          * TX: qid = QID_AC_BE + index
 555          * TX: cw_min: 2^5 = 32.
 556          * TX: cw_max: 2^10 = 1024.
 557          * BCN: qid = QID_BEACON
 558          * ATIM: qid = QID_ATIM
 559          */
 560         rt2x00queue_init(rt2x00dev, rt2x00dev->rx, QID_RX);
 561
 562         qid = QID_AC_BE;
 563         tx_queue_for_each(rt2x00dev, queue)
 564                 rt2x00queue_init(rt2x00dev, queue, qid++);
 565
 566         rt2x00queue_init(rt2x00dev, &rt2x00dev->bcn[0], QID_BEACON);
 567         if (req_atim)
 568                 rt2x00queue_init(rt2x00dev, &rt2x00dev->bcn[1], QID_ATIM);
 569
 570         return 0;
 571 }
 572
 573 void rt2x00queue_free(struct rt2x00_dev *rt2x00dev)
 574 {
 575         kfree(rt2x00dev->rx);
 576         rt2x00dev->rx = NULL;
 577         rt2x00dev->tx = NULL;
 578         rt2x00dev->bcn = NULL;
 579 }