drivers/net/wireless/st/cw1200/queue.c

   1 /*
   2  * O(1) TX queue with built-in allocator for ST-Ericsson CW1200 drivers
   3  *
   4  * Copyright (c) 2010, ST-Ericsson
   5  * Author: Dmitry Tarnyagin <dmitry.tarnyagin@lockless.no>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <net/mac80211.h>
  13 #include <linux/sched.h>
  14 #include "queue.h"
  15 #include "cw1200.h"
  16 #include "debug.h"
  17
  18 /* private */ struct cw1200_queue_item
  19 {
  20         struct list_head        head;
  21         struct sk_buff          *skb;
  22         u32                     packet_id;
  23         unsigned long           queue_timestamp;
  24         unsigned long           xmit_timestamp;
  25         struct cw1200_txpriv    txpriv;
  26         u8                      generation;
  27 };
  28
  29 static inline void __cw1200_queue_lock(struct cw1200_queue *queue)
  30 {
  31         struct cw1200_queue_stats *stats = queue->stats;
  32         if (queue->tx_locked_cnt++ == 0) {
  33                 pr_debug("[TX] Queue %d is locked.\n",
  34                          queue->queue_id);
  35                 ieee80211_stop_queue(stats->priv->hw, queue->queue_id);
  36         }
  37 }
  38
  39 static inline void __cw1200_queue_unlock(struct cw1200_queue *queue)
  40 {
  41         struct cw1200_queue_stats *stats = queue->stats;
  42         BUG_ON(!queue->tx_locked_cnt);
  43         if (--queue->tx_locked_cnt == 0) {
  44                 pr_debug("[TX] Queue %d is unlocked.\n",
  45                          queue->queue_id);
  46                 ieee80211_wake_queue(stats->priv->hw, queue->queue_id);
  47         }
  48 }
  49
  50 static inline void cw1200_queue_parse_id(u32 packet_id, u8 *queue_generation,
  51                                          u8 *queue_id, u8 *item_generation,
  52                                          u8 *item_id)
  53 {
  54         *item_id                = (packet_id >>  0) & 0xFF;
  55         *item_generation        = (packet_id >>  8) & 0xFF;
  56         *queue_id               = (packet_id >> 16) & 0xFF;
  57         *queue_generation       = (packet_id >> 24) & 0xFF;
  58 }
  59
  60 static inline u32 cw1200_queue_mk_packet_id(u8 queue_generation, u8 queue_id,
  61                                             u8 item_generation, u8 item_id)
  62 {
  63         return ((u32)item_id << 0) |
  64                 ((u32)item_generation << 8) |
  65                 ((u32)queue_id << 16) |
  66                 ((u32)queue_generation << 24);
  67 }
  68
  69 static void cw1200_queue_post_gc(struct cw1200_queue_stats *stats,
  70                                  struct list_head *gc_list)
  71 {
  72         struct cw1200_queue_item *item, *tmp;
  73
  74         list_for_each_entry_safe(item, tmp, gc_list, head) {
  75                 list_del(&item->head);
  76                 stats->skb_dtor(stats->priv, item->skb, &item->txpriv);
  77                 kfree(item);
  78         }
  79 }
  80
  81 static void cw1200_queue_register_post_gc(struct list_head *gc_list,
  82                                           struct cw1200_queue_item *item)
  83 {
  84         struct cw1200_queue_item *gc_item;
  85         gc_item = kmalloc(sizeof(struct cw1200_queue_item),
  86                         GFP_ATOMIC);
  87         BUG_ON(!gc_item);
  88         memcpy(gc_item, item, sizeof(struct cw1200_queue_item));
  89         list_add_tail(&gc_item->head, gc_list);
  90 }
  91
  92 static void __cw1200_queue_gc(struct cw1200_queue *queue,
  93                               struct list_head *head,
  94                               bool unlock)
  95 {
  96         struct cw1200_queue_stats *stats = queue->stats;
  97         struct cw1200_queue_item *item = NULL, *tmp;
  98         bool wakeup_stats = false;
  99
 100         list_for_each_entry_safe(item, tmp, &queue->queue, head) {
 101                 if (jiffies - item->queue_timestamp < queue->ttl)
 102                         break;
 103                 --queue->num_queued;
 104                 --queue->link_map_cache[item->txpriv.link_id];
 105                 spin_lock_bh(&stats->lock);
 106                 --stats->num_queued;
 107                 if (!--stats->link_map_cache[item->txpriv.link_id])
 108                         wakeup_stats = true;
 109                 spin_unlock_bh(&stats->lock);
 110                 cw1200_debug_tx_ttl(stats->priv);
 111                 cw1200_queue_register_post_gc(head, item);
 112                 item->skb = NULL;
 113                 list_move_tail(&item->head, &queue->free_pool);
 114         }
 115
 116         if (wakeup_stats)
 117                 wake_up(&stats->wait_link_id_empty);
 118
 119         if (queue->overfull) {
 120                 if (queue->num_queued <= (queue->capacity >> 1)) {
 121                         queue->overfull = false;
 122                         if (unlock)
 123                                 __cw1200_queue_unlock(queue);
 124                 } else if (item) {
 125                         unsigned long tmo = item->queue_timestamp + queue->ttl;
 126                         mod_timer(&queue->gc, tmo);
 127                         cw1200_pm_stay_awake(&stats->priv->pm_state,
 128                                              tmo - jiffies);
 129                 }
 130         }
 131 }
 132
 133 static void cw1200_queue_gc(unsigned long arg)
 134 {
 135         LIST_HEAD(list);
 136         struct cw1200_queue *queue =
 137                 (struct cw1200_queue *)arg;
 138
 139         spin_lock_bh(&queue->lock);
 140         __cw1200_queue_gc(queue, &list, true);
 141         spin_unlock_bh(&queue->lock);
 142         cw1200_queue_post_gc(queue->stats, &list);
 143 }
 144
 145 int cw1200_queue_stats_init(struct cw1200_queue_stats *stats,
 146                             size_t map_capacity,
 147                             cw1200_queue_skb_dtor_t skb_dtor,
 148                             struct cw1200_common *priv)
 149 {
 150         memset(stats, 0, sizeof(*stats));
 151         stats->map_capacity = map_capacity;
 152         stats->skb_dtor = skb_dtor;
 153         stats->priv = priv;
 154         spin_lock_init(&stats->lock);
 155         init_waitqueue_head(&stats->wait_link_id_empty);
 156
 157         stats->link_map_cache = kzalloc(sizeof(int) * map_capacity,
 158                                         GFP_KERNEL);
 159         if (!stats->link_map_cache)
 160                 return -ENOMEM;
 161
 162         return 0;
 163 }
 164
 165 int cw1200_queue_init(struct cw1200_queue *queue,
 166                       struct cw1200_queue_stats *stats,
 167                       u8 queue_id,
 168                       size_t capacity,
 169                       unsigned long ttl)
 170 {
 171         size_t i;
 172
 173         memset(queue, 0, sizeof(*queue));
 174         queue->stats = stats;
 175         queue->capacity = capacity;
 176         queue->queue_id = queue_id;
 177         queue->ttl = ttl;
 178         INIT_LIST_HEAD(&queue->queue);
 179         INIT_LIST_HEAD(&queue->pending);
 180         INIT_LIST_HEAD(&queue->free_pool);
 181         spin_lock_init(&queue->lock);
 182         setup_timer(&queue->gc, cw1200_queue_gc, (unsigned long)queue);
 183
 184         queue->pool = kzalloc(sizeof(struct cw1200_queue_item) * capacity,
 185                         GFP_KERNEL);
 186         if (!queue->pool)
 187                 return -ENOMEM;
 188
 189         queue->link_map_cache = kzalloc(sizeof(int) * stats->map_capacity,
 190                         GFP_KERNEL);
 191         if (!queue->link_map_cache) {
 192                 kfree(queue->pool);
 193                 queue->pool = NULL;
 194                 return -ENOMEM;
 195         }
 196
 197         for (i = 0; i < capacity; ++i)
 198                 list_add_tail(&queue->pool[i].head, &queue->free_pool);
 199
 200         return 0;
 201 }
 202
 203 int cw1200_queue_clear(struct cw1200_queue *queue)
 204 {
 205         int i;
 206         LIST_HEAD(gc_list);
 207         struct cw1200_queue_stats *stats = queue->stats;
 208         struct cw1200_queue_item *item, *tmp;
 209
 210         spin_lock_bh(&queue->lock);
 211         queue->generation++;
 212         list_splice_tail_init(&queue->queue, &queue->pending);
 213         list_for_each_entry_safe(item, tmp, &queue->pending, head) {
 214                 WARN_ON(!item->skb);
 215                 cw1200_queue_register_post_gc(&gc_list, item);
 216                 item->skb = NULL;
 217                 list_move_tail(&item->head, &queue->free_pool);
 218         }
 219         queue->num_queued = 0;
 220         queue->num_pending = 0;
 221
 222         spin_lock_bh(&stats->lock);
 223         for (i = 0; i < stats->map_capacity; ++i) {
 224                 stats->num_queued -= queue->link_map_cache[i];
 225                 stats->link_map_cache[i] -= queue->link_map_cache[i];
 226                 queue->link_map_cache[i] = 0;
 227         }
 228         spin_unlock_bh(&stats->lock);
 229         if (queue->overfull) {
 230                 queue->overfull = false;
 231                 __cw1200_queue_unlock(queue);
 232         }
 233         spin_unlock_bh(&queue->lock);
 234         wake_up(&stats->wait_link_id_empty);
 235         cw1200_queue_post_gc(stats, &gc_list);
 236         return 0;
 237 }
 238
 239 void cw1200_queue_stats_deinit(struct cw1200_queue_stats *stats)
 240 {
 241         kfree(stats->link_map_cache);
 242         stats->link_map_cache = NULL;
 243 }
 244
 245 void cw1200_queue_deinit(struct cw1200_queue *queue)
 246 {
 247         cw1200_queue_clear(queue);
 248         del_timer_sync(&queue->gc);
 249         INIT_LIST_HEAD(&queue->free_pool);
 250         kfree(queue->pool);
 251         kfree(queue->link_map_cache);
 252         queue->pool = NULL;
 253         queue->link_map_cache = NULL;
 254         queue->capacity = 0;
 255 }
 256
 257 size_t cw1200_queue_get_num_queued(struct cw1200_queue *queue,
 258                                    u32 link_id_map)
 259 {
 260         size_t ret;
 261         int i, bit;
 262         size_t map_capacity = queue->stats->map_capacity;
 263
 264         if (!link_id_map)
 265                 return 0;
 266
 267         spin_lock_bh(&queue->lock);
 268         if (link_id_map == (u32)-1) {
 269                 ret = queue->num_queued - queue->num_pending;
 270         } else {
 271                 ret = 0;
 272                 for (i = 0, bit = 1; i < map_capacity; ++i, bit <<= 1) {
 273                         if (link_id_map & bit)
 274                                 ret += queue->link_map_cache[i];
 275                 }
 276         }
 277         spin_unlock_bh(&queue->lock);
 278         return ret;
 279 }
 280
 281 int cw1200_queue_put(struct cw1200_queue *queue,
 282                      struct sk_buff *skb,
 283                      struct cw1200_txpriv *txpriv)
 284 {
 285         int ret = 0;
 286         LIST_HEAD(gc_list);
 287         struct cw1200_queue_stats *stats = queue->stats;
 288
 289         if (txpriv->link_id >= queue->stats->map_capacity)
 290                 return -EINVAL;
 291
 292         spin_lock_bh(&queue->lock);
 293         if (!WARN_ON(list_empty(&queue->free_pool))) {
 294                 struct cw1200_queue_item *item = list_first_entry(
 295                         &queue->free_pool, struct cw1200_queue_item, head);
 296                 BUG_ON(item->skb);
 297
 298                 list_move_tail(&item->head, &queue->queue);
 299                 item->skb = skb;
 300                 item->txpriv = *txpriv;
 301                 item->generation = 0;
 302                 item->packet_id = cw1200_queue_mk_packet_id(queue->generation,
 303                                                             queue->queue_id,
 304                                                             item->generation,
 305                                                             item - queue->pool);
 306                 item->queue_timestamp = jiffies;
 307
 308                 ++queue->num_queued;
 309                 ++queue->link_map_cache[txpriv->link_id];
 310
 311                 spin_lock_bh(&stats->lock);
 312                 ++stats->num_queued;
 313                 ++stats->link_map_cache[txpriv->link_id];
 314                 spin_unlock_bh(&stats->lock);
 315
 316                 /* TX may happen in parallel sometimes.
 317                  * Leave extra queue slots so we don't overflow.
 318                  */
 319                 if (queue->overfull == false &&
 320                     queue->num_queued >=
 321                     (queue->capacity - (num_present_cpus() - 1))) {
 322                         queue->overfull = true;
 323                         __cw1200_queue_lock(queue);
 324                         mod_timer(&queue->gc, jiffies);
 325                 }
 326         } else {
 327                 ret = -ENOENT;
 328         }
 329         spin_unlock_bh(&queue->lock);
 330         return ret;
 331 }
 332
 333 int cw1200_queue_get(struct cw1200_queue *queue,
 334                      u32 link_id_map,
 335                      struct wsm_tx **tx,
 336                      struct ieee80211_tx_info **tx_info,
 337                      const struct cw1200_txpriv **txpriv)
 338 {
 339         int ret = -ENOENT;
 340         struct cw1200_queue_item *item;
 341         struct cw1200_queue_stats *stats = queue->stats;
 342         bool wakeup_stats = false;
 343
 344         spin_lock_bh(&queue->lock);
 345         list_for_each_entry(item, &queue->queue, head) {
 346                 if (link_id_map & BIT(item->txpriv.link_id)) {
 347                         ret = 0;
 348                         break;
 349                 }
 350         }
 351
 352         if (!WARN_ON(ret)) {
 353                 *tx = (struct wsm_tx *)item->skb->data;
 354                 *tx_info = IEEE80211_SKB_CB(item->skb);
 355                 *txpriv = &item->txpriv;
 356                 (*tx)->packet_id = item->packet_id;
 357                 list_move_tail(&item->head, &queue->pending);
 358                 ++queue->num_pending;
 359                 --queue->link_map_cache[item->txpriv.link_id];
 360                 item->xmit_timestamp = jiffies;
 361
 362                 spin_lock_bh(&stats->lock);
 363                 --stats->num_queued;
 364                 if (!--stats->link_map_cache[item->txpriv.link_id])
 365                         wakeup_stats = true;
 366                 spin_unlock_bh(&stats->lock);
 367         }
 368         spin_unlock_bh(&queue->lock);
 369         if (wakeup_stats)
 370                 wake_up(&stats->wait_link_id_empty);
 371         return ret;
 372 }
 373
 374 int cw1200_queue_requeue(struct cw1200_queue *queue, u32 packet_id)
 375 {
 376         int ret = 0;
 377         u8 queue_generation, queue_id, item_generation, item_id;
 378         struct cw1200_queue_item *item;
 379         struct cw1200_queue_stats *stats = queue->stats;
 380
 381         cw1200_queue_parse_id(packet_id, &queue_generation, &queue_id,
 382                               &item_generation, &item_id);
 383
 384         item = &queue->pool[item_id];
 385
 386         spin_lock_bh(&queue->lock);
 387         BUG_ON(queue_id != queue->queue_id);
 388         if (queue_generation != queue->generation) {
 389                 ret = -ENOENT;
 390         } else if (item_id >= (unsigned) queue->capacity) {
 391                 WARN_ON(1);
 392                 ret = -EINVAL;
 393         } else if (item->generation != item_generation) {
 394                 WARN_ON(1);
 395                 ret = -ENOENT;
 396         } else {
 397                 --queue->num_pending;
 398                 ++queue->link_map_cache[item->txpriv.link_id];
 399
 400                 spin_lock_bh(&stats->lock);
 401                 ++stats->num_queued;
 402                 ++stats->link_map_cache[item->txpriv.link_id];
 403                 spin_unlock_bh(&stats->lock);
 404
 405                 item->generation = ++item_generation;
 406                 item->packet_id = cw1200_queue_mk_packet_id(queue_generation,
 407                                                             queue_id,
 408                                                             item_generation,
 409                                                             item_id);
 410                 list_move(&item->head, &queue->queue);
 411         }
 412         spin_unlock_bh(&queue->lock);
 413         return ret;
 414 }
 415
 416 int cw1200_queue_requeue_all(struct cw1200_queue *queue)
 417 {
 418         struct cw1200_queue_item *item, *tmp;
 419         struct cw1200_queue_stats *stats = queue->stats;
 420         spin_lock_bh(&queue->lock);
 421
 422         list_for_each_entry_safe_reverse(item, tmp, &queue->pending, head) {
 423                 --queue->num_pending;
 424                 ++queue->link_map_cache[item->txpriv.link_id];
 425
 426                 spin_lock_bh(&stats->lock);
 427                 ++stats->num_queued;
 428                 ++stats->link_map_cache[item->txpriv.link_id];
 429                 spin_unlock_bh(&stats->lock);
 430
 431                 ++item->generation;
 432                 item->packet_id = cw1200_queue_mk_packet_id(queue->generation,
 433                                                             queue->queue_id,
 434                                                             item->generation,
 435                                                             item - queue->pool);
 436                 list_move(&item->head, &queue->queue);
 437         }
 438         spin_unlock_bh(&queue->lock);
 439
 440         return 0;
 441 }
 442
 443 int cw1200_queue_remove(struct cw1200_queue *queue, u32 packet_id)
 444 {
 445         int ret = 0;
 446         u8 queue_generation, queue_id, item_generation, item_id;
 447         struct cw1200_queue_item *item;
 448         struct cw1200_queue_stats *stats = queue->stats;
 449         struct sk_buff *gc_skb = NULL;
 450         struct cw1200_txpriv gc_txpriv;
 451
 452         cw1200_queue_parse_id(packet_id, &queue_generation, &queue_id,
 453                               &item_generation, &item_id);
 454
 455         item = &queue->pool[item_id];
 456
 457         spin_lock_bh(&queue->lock);
 458         BUG_ON(queue_id != queue->queue_id);
 459         if (queue_generation != queue->generation) {
 460                 ret = -ENOENT;
 461         } else if (item_id >= (unsigned) queue->capacity) {
 462                 WARN_ON(1);
 463                 ret = -EINVAL;
 464         } else if (item->generation != item_generation) {
 465                 WARN_ON(1);
 466                 ret = -ENOENT;
 467         } else {
 468                 gc_txpriv = item->txpriv;
 469                 gc_skb = item->skb;
 470                 item->skb = NULL;
 471                 --queue->num_pending;
 472                 --queue->num_queued;
 473                 ++queue->num_sent;
 474                 ++item->generation;
 475                 /* Do not use list_move_tail here, but list_move:
 476                  * try to utilize cache row.
 477                  */
 478                 list_move(&item->head, &queue->free_pool);
 479
 480                 if (queue->overfull &&
 481                     (queue->num_queued <= (queue->capacity >> 1))) {
 482                         queue->overfull = false;
 483                         __cw1200_queue_unlock(queue);
 484                 }
 485         }
 486         spin_unlock_bh(&queue->lock);
 487
 488         if (gc_skb)
 489                 stats->skb_dtor(stats->priv, gc_skb, &gc_txpriv);
 490
 491         return ret;
 492 }
 493
 494 int cw1200_queue_get_skb(struct cw1200_queue *queue, u32 packet_id,
 495                          struct sk_buff **skb,
 496                          const struct cw1200_txpriv **txpriv)
 497 {
 498         int ret = 0;
 499         u8 queue_generation, queue_id, item_generation, item_id;
 500         struct cw1200_queue_item *item;
 501         cw1200_queue_parse_id(packet_id, &queue_generation, &queue_id,
 502                               &item_generation, &item_id);
 503
 504         item = &queue->pool[item_id];
 505
 506         spin_lock_bh(&queue->lock);
 507         BUG_ON(queue_id != queue->queue_id);
 508         if (queue_generation != queue->generation) {
 509                 ret = -ENOENT;
 510         } else if (item_id >= (unsigned) queue->capacity) {
 511                 WARN_ON(1);
 512                 ret = -EINVAL;
 513         } else if (item->generation != item_generation) {
 514                 WARN_ON(1);
 515                 ret = -ENOENT;
 516         } else {
 517                 *skb = item->skb;
 518                 *txpriv = &item->txpriv;
 519         }
 520         spin_unlock_bh(&queue->lock);
 521         return ret;
 522 }
 523
 524 void cw1200_queue_lock(struct cw1200_queue *queue)
 525 {
 526         spin_lock_bh(&queue->lock);
 527         __cw1200_queue_lock(queue);
 528         spin_unlock_bh(&queue->lock);
 529 }
 530
 531 void cw1200_queue_unlock(struct cw1200_queue *queue)
 532 {
 533         spin_lock_bh(&queue->lock);
 534         __cw1200_queue_unlock(queue);
 535         spin_unlock_bh(&queue->lock);
 536 }
 537
 538 bool cw1200_queue_get_xmit_timestamp(struct cw1200_queue *queue,
 539                                      unsigned long *timestamp,
 540                                      u32 pending_frame_id)
 541 {
 542         struct cw1200_queue_item *item;
 543         bool ret;
 544
 545         spin_lock_bh(&queue->lock);
 546         ret = !list_empty(&queue->pending);
 547         if (ret) {
 548                 list_for_each_entry(item, &queue->pending, head) {
 549                         if (item->packet_id != pending_frame_id)
 550                                 if (time_before(item->xmit_timestamp,
 551                                                 *timestamp))
 552                                         *timestamp = item->xmit_timestamp;
 553                 }
 554         }
 555         spin_unlock_bh(&queue->lock);
 556         return ret;
 557 }
 558
 559 bool cw1200_queue_stats_is_empty(struct cw1200_queue_stats *stats,
 560                                  u32 link_id_map)
 561 {
 562         bool empty = true;
 563
 564         spin_lock_bh(&stats->lock);
 565         if (link_id_map == (u32)-1) {
 566                 empty = stats->num_queued == 0;
 567         } else {
 568                 int i;
 569                 for (i = 0; i < stats->map_capacity; ++i) {
 570                         if (link_id_map & BIT(i)) {
 571                                 if (stats->link_map_cache[i]) {
 572                                         empty = false;
 573                                         break;
 574                                 }
 575                         }
 576                 }
 577         }
 578         spin_unlock_bh(&stats->lock);
 579
 580         return empty;
 581 }