drivers/net/wireless/iwlegacy/3945-rs.c

   1 /******************************************************************************
   2  *
   3  * Copyright(c) 2005 - 2011 Intel Corporation. All rights reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of version 2 of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA
  17  *
  18  * The full GNU General Public License is included in this distribution in the
  19  * file called LICENSE.
  20  *
  21  * Contact Information:
  22  *  Intel Linux Wireless <ilw@linux.intel.com>
  23  * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
  24  *
  25  *****************************************************************************/
  26
  27 #include <linux/kernel.h>
  28 #include <linux/init.h>
  29 #include <linux/skbuff.h>
  30 #include <linux/slab.h>
  31 #include <net/mac80211.h>
  32
  33 #include <linux/netdevice.h>
  34 #include <linux/etherdevice.h>
  35 #include <linux/delay.h>
  36
  37 #include <linux/workqueue.h>
  38
  39 #include "commands.h"
  40 #include "3945.h"
  41
  42 #define RS_NAME "iwl-3945-rs"
  43
  44 static s32 il3945_expected_tpt_g[RATE_COUNT_3945] = {
  45         7, 13, 35, 58, 0, 0, 76, 104, 130, 168, 191, 202
  46 };
  47
  48 static s32 il3945_expected_tpt_g_prot[RATE_COUNT_3945] = {
  49         7, 13, 35, 58, 0, 0, 0, 80, 93, 113, 123, 125
  50 };
  51
  52 static s32 il3945_expected_tpt_a[RATE_COUNT_3945] = {
  53         0, 0, 0, 0, 40, 57, 72, 98, 121, 154, 177, 186
  54 };
  55
  56 static s32 il3945_expected_tpt_b[RATE_COUNT_3945] = {
  57         7, 13, 35, 58, 0, 0, 0, 0, 0, 0, 0, 0
  58 };
  59
  60 struct il3945_tpt_entry {
  61         s8 min_rssi;
  62         u8 idx;
  63 };
  64
  65 static struct il3945_tpt_entry il3945_tpt_table_a[] = {
  66         {-60, RATE_54M_IDX},
  67         {-64, RATE_48M_IDX},
  68         {-72, RATE_36M_IDX},
  69         {-80, RATE_24M_IDX},
  70         {-84, RATE_18M_IDX},
  71         {-85, RATE_12M_IDX},
  72         {-87, RATE_9M_IDX},
  73         {-89, RATE_6M_IDX}
  74 };
  75
  76 static struct il3945_tpt_entry il3945_tpt_table_g[] = {
  77         {-60, RATE_54M_IDX},
  78         {-64, RATE_48M_IDX},
  79         {-68, RATE_36M_IDX},
  80         {-80, RATE_24M_IDX},
  81         {-84, RATE_18M_IDX},
  82         {-85, RATE_12M_IDX},
  83         {-86, RATE_11M_IDX},
  84         {-88, RATE_5M_IDX},
  85         {-90, RATE_2M_IDX},
  86         {-92, RATE_1M_IDX}
  87 };
  88
  89 #define RATE_MAX_WINDOW         62
  90 #define RATE_FLUSH              (3*HZ)
  91 #define RATE_WIN_FLUSH          (HZ/2)
  92 #define IL39_RATE_HIGH_TH       11520
  93 #define IL_SUCCESS_UP_TH        8960
  94 #define IL_SUCCESS_DOWN_TH      10880
  95 #define RATE_MIN_FAILURE_TH     6
  96 #define RATE_MIN_SUCCESS_TH     8
  97 #define RATE_DECREASE_TH        1920
  98 #define RATE_RETRY_TH           15
  99
 100 static u8
 101 il3945_get_rate_idx_by_rssi(s32 rssi, enum ieee80211_band band)
 102 {
 103         u32 idx = 0;
 104         u32 table_size = 0;
 105         struct il3945_tpt_entry *tpt_table = NULL;
 106
 107         if (rssi < IL_MIN_RSSI_VAL || rssi > IL_MAX_RSSI_VAL)
 108                 rssi = IL_MIN_RSSI_VAL;
 109
 110         switch (band) {
 111         case IEEE80211_BAND_2GHZ:
 112                 tpt_table = il3945_tpt_table_g;
 113                 table_size = ARRAY_SIZE(il3945_tpt_table_g);
 114                 break;
 115         case IEEE80211_BAND_5GHZ:
 116                 tpt_table = il3945_tpt_table_a;
 117                 table_size = ARRAY_SIZE(il3945_tpt_table_a);
 118                 break;
 119         default:
 120                 BUG();
 121                 break;
 122         }
 123
 124         while (idx < table_size && rssi < tpt_table[idx].min_rssi)
 125                 idx++;
 126
 127         idx = min(idx, table_size - 1);
 128
 129         return tpt_table[idx].idx;
 130 }
 131
 132 static void
 133 il3945_clear_win(struct il3945_rate_scale_data *win)
 134 {
 135         win->data = 0;
 136         win->success_counter = 0;
 137         win->success_ratio = -1;
 138         win->counter = 0;
 139         win->average_tpt = IL_INVALID_VALUE;
 140         win->stamp = 0;
 141 }
 142
 143 /**
 144  * il3945_rate_scale_flush_wins - flush out the rate scale wins
 145  *
 146  * Returns the number of wins that have gathered data but were
 147  * not flushed.  If there were any that were not flushed, then
 148  * reschedule the rate flushing routine.
 149  */
 150 static int
 151 il3945_rate_scale_flush_wins(struct il3945_rs_sta *rs_sta)
 152 {
 153         int unflushed = 0;
 154         int i;
 155         unsigned long flags;
 156         struct il_priv *il __maybe_unused = rs_sta->il;
 157
 158         /*
 159          * For each rate, if we have collected data on that rate
 160          * and it has been more than RATE_WIN_FLUSH
 161          * since we flushed, clear out the gathered stats
 162          */
 163         for (i = 0; i < RATE_COUNT_3945; i++) {
 164                 if (!rs_sta->win[i].counter)
 165                         continue;
 166
 167                 spin_lock_irqsave(&rs_sta->lock, flags);
 168                 if (time_after(jiffies, rs_sta->win[i].stamp + RATE_WIN_FLUSH)) {
 169                         D_RATE("flushing %d samples of rate " "idx %d\n",
 170                                rs_sta->win[i].counter, i);
 171                         il3945_clear_win(&rs_sta->win[i]);
 172                 } else
 173                         unflushed++;
 174                 spin_unlock_irqrestore(&rs_sta->lock, flags);
 175         }
 176
 177         return unflushed;
 178 }
 179
 180 #define RATE_FLUSH_MAX              5000        /* msec */
 181 #define RATE_FLUSH_MIN              50  /* msec */
 182 #define IL_AVERAGE_PACKETS             1500
 183
 184 static void
 185 il3945_bg_rate_scale_flush(unsigned long data)
 186 {
 187         struct il3945_rs_sta *rs_sta = (void *)data;
 188         struct il_priv *il __maybe_unused = rs_sta->il;
 189         int unflushed = 0;
 190         unsigned long flags;
 191         u32 packet_count, duration, pps;
 192
 193         D_RATE("enter\n");
 194
 195         unflushed = il3945_rate_scale_flush_wins(rs_sta);
 196
 197         spin_lock_irqsave(&rs_sta->lock, flags);
 198
 199         /* Number of packets Rx'd since last time this timer ran */
 200         packet_count = (rs_sta->tx_packets - rs_sta->last_tx_packets) + 1;
 201
 202         rs_sta->last_tx_packets = rs_sta->tx_packets + 1;
 203
 204         if (unflushed) {
 205                 duration =
 206                     jiffies_to_msecs(jiffies - rs_sta->last_partial_flush);
 207
 208                 D_RATE("Tx'd %d packets in %dms\n", packet_count, duration);
 209
 210                 /* Determine packets per second */
 211                 if (duration)
 212                         pps = (packet_count * 1000) / duration;
 213                 else
 214                         pps = 0;
 215
 216                 if (pps) {
 217                         duration = (IL_AVERAGE_PACKETS * 1000) / pps;
 218                         if (duration < RATE_FLUSH_MIN)
 219                                 duration = RATE_FLUSH_MIN;
 220                         else if (duration > RATE_FLUSH_MAX)
 221                                 duration = RATE_FLUSH_MAX;
 222                 } else
 223                         duration = RATE_FLUSH_MAX;
 224
 225                 rs_sta->flush_time = msecs_to_jiffies(duration);
 226
 227                 D_RATE("new flush period: %d msec ave %d\n", duration,
 228                        packet_count);
 229
 230                 mod_timer(&rs_sta->rate_scale_flush,
 231                           jiffies + rs_sta->flush_time);
 232
 233                 rs_sta->last_partial_flush = jiffies;
 234         } else {
 235                 rs_sta->flush_time = RATE_FLUSH;
 236                 rs_sta->flush_pending = 0;
 237         }
 238         /* If there weren't any unflushed entries, we don't schedule the timer
 239          * to run again */
 240
 241         rs_sta->last_flush = jiffies;
 242
 243         spin_unlock_irqrestore(&rs_sta->lock, flags);
 244
 245         D_RATE("leave\n");
 246 }
 247
 248 /**
 249  * il3945_collect_tx_data - Update the success/failure sliding win
 250  *
 251  * We keep a sliding win of the last 64 packets transmitted
 252  * at this rate.  win->data contains the bitmask of successful
 253  * packets.
 254  */
 255 static void
 256 il3945_collect_tx_data(struct il3945_rs_sta *rs_sta,
 257                        struct il3945_rate_scale_data *win, int success,
 258                        int retries, int idx)
 259 {
 260         unsigned long flags;
 261         s32 fail_count;
 262         struct il_priv *il __maybe_unused = rs_sta->il;
 263
 264         if (!retries) {
 265                 D_RATE("leave: retries == 0 -- should be at least 1\n");
 266                 return;
 267         }
 268
 269         spin_lock_irqsave(&rs_sta->lock, flags);
 270
 271         /*
 272          * Keep track of only the latest 62 tx frame attempts in this rate's
 273          * history win; anything older isn't really relevant any more.
 274          * If we have filled up the sliding win, drop the oldest attempt;
 275          * if the oldest attempt (highest bit in bitmap) shows "success",
 276          * subtract "1" from the success counter (this is the main reason
 277          * we keep these bitmaps!).
 278          * */
 279         while (retries > 0) {
 280                 if (win->counter >= RATE_MAX_WINDOW) {
 281
 282                         /* remove earliest */
 283                         win->counter = RATE_MAX_WINDOW - 1;
 284
 285                         if (win->data & (1ULL << (RATE_MAX_WINDOW - 1))) {
 286                                 win->data &= ~(1ULL << (RATE_MAX_WINDOW - 1));
 287                                 win->success_counter--;
 288                         }
 289                 }
 290
 291                 /* Increment frames-attempted counter */
 292                 win->counter++;
 293
 294                 /* Shift bitmap by one frame (throw away oldest history),
 295                  * OR in "1", and increment "success" if this
 296                  * frame was successful. */
 297                 win->data <<= 1;
 298                 if (success > 0) {
 299                         win->success_counter++;
 300                         win->data |= 0x1;
 301                         success--;
 302                 }
 303
 304                 retries--;
 305         }
 306
 307         /* Calculate current success ratio, avoid divide-by-0! */
 308         if (win->counter > 0)
 309                 win->success_ratio =
 310                     128 * (100 * win->success_counter) / win->counter;
 311         else
 312                 win->success_ratio = IL_INVALID_VALUE;
 313
 314         fail_count = win->counter - win->success_counter;
 315
 316         /* Calculate average throughput, if we have enough history. */
 317         if (fail_count >= RATE_MIN_FAILURE_TH ||
 318             win->success_counter >= RATE_MIN_SUCCESS_TH)
 319                 win->average_tpt =
 320                     ((win->success_ratio * rs_sta->expected_tpt[idx] +
 321                       64) / 128);
 322         else
 323                 win->average_tpt = IL_INVALID_VALUE;
 324
 325         /* Tag this win as having been updated */
 326         win->stamp = jiffies;
 327
 328         spin_unlock_irqrestore(&rs_sta->lock, flags);
 329 }
 330
 331 /*
 332  * Called after adding a new station to initialize rate scaling
 333  */
 334 void
 335 il3945_rs_rate_init(struct il_priv *il, struct ieee80211_sta *sta, u8 sta_id)
 336 {
 337         struct ieee80211_hw *hw = il->hw;
 338         struct ieee80211_conf *conf = &il->hw->conf;
 339         struct il3945_sta_priv *psta;
 340         struct il3945_rs_sta *rs_sta;
 341         struct ieee80211_supported_band *sband;
 342         int i;
 343
 344         D_INFO("enter\n");
 345         if (sta_id == il->ctx.bcast_sta_id)
 346                 goto out;
 347
 348         psta = (struct il3945_sta_priv *)sta->drv_priv;
 349         rs_sta = &psta->rs_sta;
 350         sband = hw->wiphy->bands[conf->channel->band];
 351
 352         rs_sta->il = il;
 353
 354         rs_sta->start_rate = RATE_INVALID;
 355
 356         /* default to just 802.11b */
 357         rs_sta->expected_tpt = il3945_expected_tpt_b;
 358
 359         rs_sta->last_partial_flush = jiffies;
 360         rs_sta->last_flush = jiffies;
 361         rs_sta->flush_time = RATE_FLUSH;
 362         rs_sta->last_tx_packets = 0;
 363
 364         rs_sta->rate_scale_flush.data = (unsigned long)rs_sta;
 365         rs_sta->rate_scale_flush.function = il3945_bg_rate_scale_flush;
 366
 367         for (i = 0; i < RATE_COUNT_3945; i++)
 368                 il3945_clear_win(&rs_sta->win[i]);
 369
 370         /* TODO: what is a good starting rate for STA? About middle? Maybe not
 371          * the lowest or the highest rate.. Could consider using RSSI from
 372          * previous packets? Need to have IEEE 802.1X auth succeed immediately
 373          * after assoc.. */
 374
 375         for (i = sband->n_bitrates - 1; i >= 0; i--) {
 376                 if (sta->supp_rates[sband->band] & (1 << i)) {
 377                         rs_sta->last_txrate_idx = i;
 378                         break;
 379                 }
 380         }
 381
 382         il->_3945.sta_supp_rates = sta->supp_rates[sband->band];
 383         /* For 5 GHz band it start at IL_FIRST_OFDM_RATE */
 384         if (sband->band == IEEE80211_BAND_5GHZ) {
 385                 rs_sta->last_txrate_idx += IL_FIRST_OFDM_RATE;
 386                 il->_3945.sta_supp_rates <<= IL_FIRST_OFDM_RATE;
 387         }
 388
 389 out:
 390         il->stations[sta_id].used &= ~IL_STA_UCODE_INPROGRESS;
 391
 392         D_INFO("leave\n");
 393 }
 394
 395 static void *
 396 il3945_rs_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
 397 {
 398         return hw->priv;
 399 }
 400
 401 /* rate scale requires free function to be implemented */
 402 static void
 403 il3945_rs_free(void *il)
 404 {
 405 }
 406
 407 static void *
 408 il3945_rs_alloc_sta(void *il_priv, struct ieee80211_sta *sta, gfp_t gfp)
 409 {
 410         struct il3945_rs_sta *rs_sta;
 411         struct il3945_sta_priv *psta = (void *)sta->drv_priv;
 412         struct il_priv *il __maybe_unused = il_priv;
 413
 414         D_RATE("enter\n");
 415
 416         rs_sta = &psta->rs_sta;
 417
 418         spin_lock_init(&rs_sta->lock);
 419         init_timer(&rs_sta->rate_scale_flush);
 420
 421         D_RATE("leave\n");
 422
 423         return rs_sta;
 424 }
 425
 426 static void
 427 il3945_rs_free_sta(void *il_priv, struct ieee80211_sta *sta, void *il_sta)
 428 {
 429         struct il3945_rs_sta *rs_sta = il_sta;
 430
 431         /*
 432          * Be careful not to use any members of il3945_rs_sta (like trying
 433          * to use il_priv to print out debugging) since it may not be fully
 434          * initialized at this point.
 435          */
 436         del_timer_sync(&rs_sta->rate_scale_flush);
 437 }
 438
 439 /**
 440  * il3945_rs_tx_status - Update rate control values based on Tx results
 441  *
 442  * NOTE: Uses il_priv->retry_rate for the # of retries attempted by
 443  * the hardware for each rate.
 444  */
 445 static void
 446 il3945_rs_tx_status(void *il_rate, struct ieee80211_supported_band *sband,
 447                     struct ieee80211_sta *sta, void *il_sta,
 448                     struct sk_buff *skb)
 449 {
 450         s8 retries = 0, current_count;
 451         int scale_rate_idx, first_idx, last_idx;
 452         unsigned long flags;
 453         struct il_priv *il = (struct il_priv *)il_rate;
 454         struct il3945_rs_sta *rs_sta = il_sta;
 455         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 456
 457         D_RATE("enter\n");
 458
 459         retries = info->status.rates[0].count;
 460         /* Sanity Check for retries */
 461         if (retries > RATE_RETRY_TH)
 462                 retries = RATE_RETRY_TH;
 463
 464         first_idx = sband->bitrates[info->status.rates[0].idx].hw_value;
 465         if (first_idx < 0 || first_idx >= RATE_COUNT_3945) {
 466                 D_RATE("leave: Rate out of bounds: %d\n", first_idx);
 467                 return;
 468         }
 469
 470         if (!il_sta) {
 471                 D_RATE("leave: No STA il data to update!\n");
 472                 return;
 473         }
 474
 475         /* Treat uninitialized rate scaling data same as non-existing. */
 476         if (!rs_sta->il) {
 477                 D_RATE("leave: STA il data uninitialized!\n");
 478                 return;
 479         }
 480
 481         rs_sta->tx_packets++;
 482
 483         scale_rate_idx = first_idx;
 484         last_idx = first_idx;
 485
 486         /*
 487          * Update the win for each rate.  We determine which rates
 488          * were Tx'd based on the total number of retries vs. the number
 489          * of retries configured for each rate -- currently set to the
 490          * il value 'retry_rate' vs. rate specific
 491          *
 492          * On exit from this while loop last_idx indicates the rate
 493          * at which the frame was finally transmitted (or failed if no
 494          * ACK)
 495          */
 496         while (retries > 1) {
 497                 if ((retries - 1) < il->retry_rate) {
 498                         current_count = (retries - 1);
 499                         last_idx = scale_rate_idx;
 500                 } else {
 501                         current_count = il->retry_rate;
 502                         last_idx = il3945_rs_next_rate(il, scale_rate_idx);
 503                 }
 504
 505                 /* Update this rate accounting for as many retries
 506                  * as was used for it (per current_count) */
 507                 il3945_collect_tx_data(rs_sta, &rs_sta->win[scale_rate_idx], 0,
 508                                        current_count, scale_rate_idx);
 509                 D_RATE("Update rate %d for %d retries.\n", scale_rate_idx,
 510                        current_count);
 511
 512                 retries -= current_count;
 513
 514                 scale_rate_idx = last_idx;
 515         }
 516
 517         /* Update the last idx win with success/failure based on ACK */
 518         D_RATE("Update rate %d with %s.\n", last_idx,
 519                (info->flags & IEEE80211_TX_STAT_ACK) ? "success" : "failure");
 520         il3945_collect_tx_data(rs_sta, &rs_sta->win[last_idx],
 521                                info->flags & IEEE80211_TX_STAT_ACK, 1,
 522                                last_idx);
 523
 524         /* We updated the rate scale win -- if its been more than
 525          * flush_time since the last run, schedule the flush
 526          * again */
 527         spin_lock_irqsave(&rs_sta->lock, flags);
 528
 529         if (!rs_sta->flush_pending &&
 530             time_after(jiffies, rs_sta->last_flush + rs_sta->flush_time)) {
 531
 532                 rs_sta->last_partial_flush = jiffies;
 533                 rs_sta->flush_pending = 1;
 534                 mod_timer(&rs_sta->rate_scale_flush,
 535                           jiffies + rs_sta->flush_time);
 536         }
 537
 538         spin_unlock_irqrestore(&rs_sta->lock, flags);
 539
 540         D_RATE("leave\n");
 541 }
 542
 543 static u16
 544 il3945_get_adjacent_rate(struct il3945_rs_sta *rs_sta, u8 idx, u16 rate_mask,
 545                          enum ieee80211_band band)
 546 {
 547         u8 high = RATE_INVALID;
 548         u8 low = RATE_INVALID;
 549         struct il_priv *il __maybe_unused = rs_sta->il;
 550
 551         /* 802.11A walks to the next literal adjacent rate in
 552          * the rate table */
 553         if (unlikely(band == IEEE80211_BAND_5GHZ)) {
 554                 int i;
 555                 u32 mask;
 556
 557                 /* Find the previous rate that is in the rate mask */
 558                 i = idx - 1;
 559                 for (mask = (1 << i); i >= 0; i--, mask >>= 1) {
 560                         if (rate_mask & mask) {
 561                                 low = i;
 562                                 break;
 563                         }
 564                 }
 565
 566                 /* Find the next rate that is in the rate mask */
 567                 i = idx + 1;
 568                 for (mask = (1 << i); i < RATE_COUNT_3945; i++, mask <<= 1) {
 569                         if (rate_mask & mask) {
 570                                 high = i;
 571                                 break;
 572                         }
 573                 }
 574
 575                 return (high << 8) | low;
 576         }
 577
 578         low = idx;
 579         while (low != RATE_INVALID) {
 580                 if (rs_sta->tgg)
 581                         low = il3945_rates[low].prev_rs_tgg;
 582                 else
 583                         low = il3945_rates[low].prev_rs;
 584                 if (low == RATE_INVALID)
 585                         break;
 586                 if (rate_mask & (1 << low))
 587                         break;
 588                 D_RATE("Skipping masked lower rate: %d\n", low);
 589         }
 590
 591         high = idx;
 592         while (high != RATE_INVALID) {
 593                 if (rs_sta->tgg)
 594                         high = il3945_rates[high].next_rs_tgg;
 595                 else
 596                         high = il3945_rates[high].next_rs;
 597                 if (high == RATE_INVALID)
 598                         break;
 599                 if (rate_mask & (1 << high))
 600                         break;
 601                 D_RATE("Skipping masked higher rate: %d\n", high);
 602         }
 603
 604         return (high << 8) | low;
 605 }
 606
 607 /**
 608  * il3945_rs_get_rate - find the rate for the requested packet
 609  *
 610  * Returns the ieee80211_rate structure allocated by the driver.
 611  *
 612  * The rate control algorithm has no internal mapping between hw_mode's
 613  * rate ordering and the rate ordering used by the rate control algorithm.
 614  *
 615  * The rate control algorithm uses a single table of rates that goes across
 616  * the entire A/B/G spectrum vs. being limited to just one particular
 617  * hw_mode.
 618  *
 619  * As such, we can't convert the idx obtained below into the hw_mode's
 620  * rate table and must reference the driver allocated rate table
 621  *
 622  */
 623 static void
 624 il3945_rs_get_rate(void *il_r, struct ieee80211_sta *sta, void *il_sta,
 625                    struct ieee80211_tx_rate_control *txrc)
 626 {
 627         struct ieee80211_supported_band *sband = txrc->sband;
 628         struct sk_buff *skb = txrc->skb;
 629         u8 low = RATE_INVALID;
 630         u8 high = RATE_INVALID;
 631         u16 high_low;
 632         int idx;
 633         struct il3945_rs_sta *rs_sta = il_sta;
 634         struct il3945_rate_scale_data *win = NULL;
 635         int current_tpt = IL_INVALID_VALUE;
 636         int low_tpt = IL_INVALID_VALUE;
 637         int high_tpt = IL_INVALID_VALUE;
 638         u32 fail_count;
 639         s8 scale_action = 0;
 640         unsigned long flags;
 641         u16 rate_mask;
 642         s8 max_rate_idx = -1;
 643         struct il_priv *il __maybe_unused = (struct il_priv *)il_r;
 644         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 645
 646         D_RATE("enter\n");
 647
 648         /* Treat uninitialized rate scaling data same as non-existing. */
 649         if (rs_sta && !rs_sta->il) {
 650                 D_RATE("Rate scaling information not initialized yet.\n");
 651                 il_sta = NULL;
 652         }
 653
 654         if (rate_control_send_low(sta, il_sta, txrc))
 655                 return;
 656
 657         rate_mask = sta->supp_rates[sband->band];
 658
 659         /* get user max rate if set */
 660         max_rate_idx = txrc->max_rate_idx;
 661         if (sband->band == IEEE80211_BAND_5GHZ && max_rate_idx != -1)
 662                 max_rate_idx += IL_FIRST_OFDM_RATE;
 663         if (max_rate_idx < 0 || max_rate_idx >= RATE_COUNT)
 664                 max_rate_idx = -1;
 665
 666         idx = min(rs_sta->last_txrate_idx & 0xffff, RATE_COUNT_3945 - 1);
 667
 668         if (sband->band == IEEE80211_BAND_5GHZ)
 669                 rate_mask = rate_mask << IL_FIRST_OFDM_RATE;
 670
 671         spin_lock_irqsave(&rs_sta->lock, flags);
 672
 673         /* for recent assoc, choose best rate regarding
 674          * to rssi value
 675          */
 676         if (rs_sta->start_rate != RATE_INVALID) {
 677                 if (rs_sta->start_rate < idx &&
 678                     (rate_mask & (1 << rs_sta->start_rate)))
 679                         idx = rs_sta->start_rate;
 680                 rs_sta->start_rate = RATE_INVALID;
 681         }
 682
 683         /* force user max rate if set by user */
 684         if (max_rate_idx != -1 && max_rate_idx < idx) {
 685                 if (rate_mask & (1 << max_rate_idx))
 686                         idx = max_rate_idx;
 687         }
 688
 689         win = &(rs_sta->win[idx]);
 690
 691         fail_count = win->counter - win->success_counter;
 692
 693         if (fail_count < RATE_MIN_FAILURE_TH &&
 694             win->success_counter < RATE_MIN_SUCCESS_TH) {
 695                 spin_unlock_irqrestore(&rs_sta->lock, flags);
 696
 697                 D_RATE("Invalid average_tpt on rate %d: "
 698                        "counter: %d, success_counter: %d, "
 699                        "expected_tpt is %sNULL\n", idx, win->counter,
 700                        win->success_counter,
 701                        rs_sta->expected_tpt ? "not " : "");
 702
 703                 /* Can't calculate this yet; not enough history */
 704                 win->average_tpt = IL_INVALID_VALUE;
 705                 goto out;
 706
 707         }
 708
 709         current_tpt = win->average_tpt;
 710
 711         high_low =
 712             il3945_get_adjacent_rate(rs_sta, idx, rate_mask, sband->band);
 713         low = high_low & 0xff;
 714         high = (high_low >> 8) & 0xff;
 715
 716         /* If user set max rate, dont allow higher than user constrain */
 717         if (max_rate_idx != -1 && max_rate_idx < high)
 718                 high = RATE_INVALID;
 719
 720         /* Collect Measured throughputs of adjacent rates */
 721         if (low != RATE_INVALID)
 722                 low_tpt = rs_sta->win[low].average_tpt;
 723
 724         if (high != RATE_INVALID)
 725                 high_tpt = rs_sta->win[high].average_tpt;
 726
 727         spin_unlock_irqrestore(&rs_sta->lock, flags);
 728
 729         scale_action = 0;
 730
 731         /* Low success ratio , need to drop the rate */
 732         if (win->success_ratio < RATE_DECREASE_TH || !current_tpt) {
 733                 D_RATE("decrease rate because of low success_ratio\n");
 734                 scale_action = -1;
 735                 /* No throughput measured yet for adjacent rates,
 736                  * try increase */
 737         } else if (low_tpt == IL_INVALID_VALUE && high_tpt == IL_INVALID_VALUE) {
 738
 739                 if (high != RATE_INVALID &&
 740                     win->success_ratio >= RATE_INCREASE_TH)
 741                         scale_action = 1;
 742                 else if (low != RATE_INVALID)
 743                         scale_action = 0;
 744
 745                 /* Both adjacent throughputs are measured, but neither one has
 746                  * better throughput; we're using the best rate, don't change
 747                  * it! */
 748         } else if (low_tpt != IL_INVALID_VALUE && high_tpt != IL_INVALID_VALUE
 749                    && low_tpt < current_tpt && high_tpt < current_tpt) {
 750
 751                 D_RATE("No action -- low [%d] & high [%d] < "
 752                        "current_tpt [%d]\n", low_tpt, high_tpt, current_tpt);
 753                 scale_action = 0;
 754
 755                 /* At least one of the rates has better throughput */
 756         } else {
 757                 if (high_tpt != IL_INVALID_VALUE) {
 758
 759                         /* High rate has better throughput, Increase
 760                          * rate */
 761                         if (high_tpt > current_tpt &&
 762                             win->success_ratio >= RATE_INCREASE_TH)
 763                                 scale_action = 1;
 764                         else {
 765                                 D_RATE("decrease rate because of high tpt\n");
 766                                 scale_action = 0;
 767                         }
 768                 } else if (low_tpt != IL_INVALID_VALUE) {
 769                         if (low_tpt > current_tpt) {
 770                                 D_RATE("decrease rate because of low tpt\n");
 771                                 scale_action = -1;
 772                         } else if (win->success_ratio >= RATE_INCREASE_TH) {
 773                                 /* Lower rate has better
 774                                  * throughput,decrease rate */
 775                                 scale_action = 1;
 776                         }
 777                 }
 778         }
 779
 780         /* Sanity check; asked for decrease, but success rate or throughput
 781          * has been good at old rate.  Don't change it. */
 782         if (scale_action == -1 && low != RATE_INVALID &&
 783             (win->success_ratio > RATE_HIGH_TH ||
 784              current_tpt > 100 * rs_sta->expected_tpt[low]))
 785                 scale_action = 0;
 786
 787         switch (scale_action) {
 788         case -1:
 789                 /* Decrese rate */
 790                 if (low != RATE_INVALID)
 791                         idx = low;
 792                 break;
 793         case 1:
 794                 /* Increase rate */
 795                 if (high != RATE_INVALID)
 796                         idx = high;
 797
 798                 break;
 799         case 0:
 800         default:
 801                 /* No change */
 802                 break;
 803         }
 804
 805         D_RATE("Selected %d (action %d) - low %d high %d\n", idx, scale_action,
 806                low, high);
 807
 808 out:
 809
 810         if (sband->band == IEEE80211_BAND_5GHZ) {
 811                 if (WARN_ON_ONCE(idx < IL_FIRST_OFDM_RATE))
 812                         idx = IL_FIRST_OFDM_RATE;
 813                 rs_sta->last_txrate_idx = idx;
 814                 info->control.rates[0].idx = idx - IL_FIRST_OFDM_RATE;
 815         } else {
 816                 rs_sta->last_txrate_idx = idx;
 817                 info->control.rates[0].idx = rs_sta->last_txrate_idx;
 818         }
 819
 820         D_RATE("leave: %d\n", idx);
 821 }
 822
 823 #ifdef CONFIG_MAC80211_DEBUGFS
 824 static int
 825 il3945_open_file_generic(struct inode *inode, struct file *file)
 826 {
 827         file->private_data = inode->i_private;
 828         return 0;
 829 }
 830
 831 static ssize_t
 832 il3945_sta_dbgfs_stats_table_read(struct file *file, char __user *user_buf,
 833                                   size_t count, loff_t *ppos)
 834 {
 835         char *buff;
 836         int desc = 0;
 837         int j;
 838         ssize_t ret;
 839         struct il3945_rs_sta *lq_sta = file->private_data;
 840
 841         buff = kmalloc(1024, GFP_KERNEL);
 842         if (!buff)
 843                 return -ENOMEM;
 844
 845         desc +=
 846             sprintf(buff + desc,
 847                     "tx packets=%d last rate idx=%d\n"
 848                     "rate=0x%X flush time %d\n", lq_sta->tx_packets,
 849                     lq_sta->last_txrate_idx, lq_sta->start_rate,
 850                     jiffies_to_msecs(lq_sta->flush_time));
 851         for (j = 0; j < RATE_COUNT_3945; j++) {
 852                 desc +=
 853                     sprintf(buff + desc, "counter=%d success=%d %%=%d\n",
 854                             lq_sta->win[j].counter,
 855                             lq_sta->win[j].success_counter,
 856                             lq_sta->win[j].success_ratio);
 857         }
 858         ret = simple_read_from_buffer(user_buf, count, ppos, buff, desc);
 859         kfree(buff);
 860         return ret;
 861 }
 862
 863 static const struct file_operations rs_sta_dbgfs_stats_table_ops = {
 864         .read = il3945_sta_dbgfs_stats_table_read,
 865         .open = il3945_open_file_generic,
 866         .llseek = default_llseek,
 867 };
 868
 869 static void
 870 il3945_add_debugfs(void *il, void *il_sta, struct dentry *dir)
 871 {
 872         struct il3945_rs_sta *lq_sta = il_sta;
 873
 874         lq_sta->rs_sta_dbgfs_stats_table_file =
 875             debugfs_create_file("rate_stats_table", 0600, dir, lq_sta,
 876                                 &rs_sta_dbgfs_stats_table_ops);
 877
 878 }
 879
 880 static void
 881 il3945_remove_debugfs(void *il, void *il_sta)
 882 {
 883         struct il3945_rs_sta *lq_sta = il_sta;
 884         debugfs_remove(lq_sta->rs_sta_dbgfs_stats_table_file);
 885 }
 886 #endif
 887
 888 /*
 889  * Initialization of rate scaling information is done by driver after
 890  * the station is added. Since mac80211 calls this function before a
 891  * station is added we ignore it.
 892  */
 893 static void
 894 il3945_rs_rate_init_stub(void *il_r, struct ieee80211_supported_band *sband,
 895                          struct ieee80211_sta *sta, void *il_sta)
 896 {
 897 }
 898
 899 static struct rate_control_ops rs_ops = {
 900         .module = NULL,
 901         .name = RS_NAME,
 902         .tx_status = il3945_rs_tx_status,
 903         .get_rate = il3945_rs_get_rate,
 904         .rate_init = il3945_rs_rate_init_stub,
 905         .alloc = il3945_rs_alloc,
 906         .free = il3945_rs_free,
 907         .alloc_sta = il3945_rs_alloc_sta,
 908         .free_sta = il3945_rs_free_sta,
 909 #ifdef CONFIG_MAC80211_DEBUGFS
 910         .add_sta_debugfs = il3945_add_debugfs,
 911         .remove_sta_debugfs = il3945_remove_debugfs,
 912 #endif
 913
 914 };
 915
 916 void
 917 il3945_rate_scale_init(struct ieee80211_hw *hw, s32 sta_id)
 918 {
 919         struct il_priv *il = hw->priv;
 920         s32 rssi = 0;
 921         unsigned long flags;
 922         struct il3945_rs_sta *rs_sta;
 923         struct ieee80211_sta *sta;
 924         struct il3945_sta_priv *psta;
 925
 926         D_RATE("enter\n");
 927
 928         rcu_read_lock();
 929
 930         sta =
 931             ieee80211_find_sta(il->ctx.vif, il->stations[sta_id].sta.sta.addr);
 932         if (!sta) {
 933                 D_RATE("Unable to find station to initialize rate scaling.\n");
 934                 rcu_read_unlock();
 935                 return;
 936         }
 937
 938         psta = (void *)sta->drv_priv;
 939         rs_sta = &psta->rs_sta;
 940
 941         spin_lock_irqsave(&rs_sta->lock, flags);
 942
 943         rs_sta->tgg = 0;
 944         switch (il->band) {
 945         case IEEE80211_BAND_2GHZ:
 946                 /* TODO: this always does G, not a regression */
 947                 if (il->ctx.active.flags & RXON_FLG_TGG_PROTECT_MSK) {
 948                         rs_sta->tgg = 1;
 949                         rs_sta->expected_tpt = il3945_expected_tpt_g_prot;
 950                 } else
 951                         rs_sta->expected_tpt = il3945_expected_tpt_g;
 952                 break;
 953         case IEEE80211_BAND_5GHZ:
 954                 rs_sta->expected_tpt = il3945_expected_tpt_a;
 955                 break;
 956         case IEEE80211_NUM_BANDS:
 957                 BUG();
 958                 break;
 959         }
 960
 961         spin_unlock_irqrestore(&rs_sta->lock, flags);
 962
 963         rssi = il->_3945.last_rx_rssi;
 964         if (rssi == 0)
 965                 rssi = IL_MIN_RSSI_VAL;
 966
 967         D_RATE("Network RSSI: %d\n", rssi);
 968
 969         rs_sta->start_rate = il3945_get_rate_idx_by_rssi(rssi, il->band);
 970
 971         D_RATE("leave: rssi %d assign rate idx: " "%d (plcp 0x%x)\n", rssi,
 972                rs_sta->start_rate, il3945_rates[rs_sta->start_rate].plcp);
 973         rcu_read_unlock();
 974 }
 975
 976 int
 977 il3945_rate_control_register(void)
 978 {
 979         return ieee80211_rate_control_register(&rs_ops);
 980 }
 981
 982 void
 983 il3945_rate_control_unregister(void)
 984 {
 985         ieee80211_rate_control_unregister(&rs_ops);
 986 }