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

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /******************************************************************************
   3  *
   4  * Copyright(c) 2005 - 2011 Intel Corporation. All rights reserved.
   5  *
   6  * Contact Information:
   7  *  Intel Linux Wireless <ilw@linux.intel.com>
   8  * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
   9  *
  10  *****************************************************************************/
  11
  12 #include <linux/kernel.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/slab.h>
  15 #include <net/mac80211.h>
  16
  17 #include <linux/netdevice.h>
  18 #include <linux/etherdevice.h>
  19 #include <linux/delay.h>
  20
  21 #include <linux/workqueue.h>
  22
  23 #include "commands.h"
  24 #include "3945.h"
  25
  26 #define RS_NAME "iwl-3945-rs"
  27
  28 static s32 il3945_expected_tpt_g[RATE_COUNT_3945] = {
  29         7, 13, 35, 58, 0, 0, 76, 104, 130, 168, 191, 202
  30 };
  31
  32 static s32 il3945_expected_tpt_g_prot[RATE_COUNT_3945] = {
  33         7, 13, 35, 58, 0, 0, 0, 80, 93, 113, 123, 125
  34 };
  35
  36 static s32 il3945_expected_tpt_a[RATE_COUNT_3945] = {
  37         0, 0, 0, 0, 40, 57, 72, 98, 121, 154, 177, 186
  38 };
  39
  40 static s32 il3945_expected_tpt_b[RATE_COUNT_3945] = {
  41         7, 13, 35, 58, 0, 0, 0, 0, 0, 0, 0, 0
  42 };
  43
  44 struct il3945_tpt_entry {
  45         s8 min_rssi;
  46         u8 idx;
  47 };
  48
  49 static struct il3945_tpt_entry il3945_tpt_table_a[] = {
  50         {-60, RATE_54M_IDX},
  51         {-64, RATE_48M_IDX},
  52         {-72, RATE_36M_IDX},
  53         {-80, RATE_24M_IDX},
  54         {-84, RATE_18M_IDX},
  55         {-85, RATE_12M_IDX},
  56         {-87, RATE_9M_IDX},
  57         {-89, RATE_6M_IDX}
  58 };
  59
  60 static struct il3945_tpt_entry il3945_tpt_table_g[] = {
  61         {-60, RATE_54M_IDX},
  62         {-64, RATE_48M_IDX},
  63         {-68, RATE_36M_IDX},
  64         {-80, RATE_24M_IDX},
  65         {-84, RATE_18M_IDX},
  66         {-85, RATE_12M_IDX},
  67         {-86, RATE_11M_IDX},
  68         {-88, RATE_5M_IDX},
  69         {-90, RATE_2M_IDX},
  70         {-92, RATE_1M_IDX}
  71 };
  72
  73 #define RATE_MAX_WINDOW         62
  74 #define RATE_FLUSH              (3*HZ)
  75 #define RATE_WIN_FLUSH          (HZ/2)
  76 #define IL39_RATE_HIGH_TH       11520
  77 #define IL_SUCCESS_UP_TH        8960
  78 #define IL_SUCCESS_DOWN_TH      10880
  79 #define RATE_MIN_FAILURE_TH     6
  80 #define RATE_MIN_SUCCESS_TH     8
  81 #define RATE_DECREASE_TH        1920
  82 #define RATE_RETRY_TH           15
  83
  84 static u8
  85 il3945_get_rate_idx_by_rssi(s32 rssi, enum nl80211_band band)
  86 {
  87         u32 idx = 0;
  88         u32 table_size = 0;
  89         struct il3945_tpt_entry *tpt_table = NULL;
  90
  91         if (rssi < IL_MIN_RSSI_VAL || rssi > IL_MAX_RSSI_VAL)
  92                 rssi = IL_MIN_RSSI_VAL;
  93
  94         switch (band) {
  95         case NL80211_BAND_2GHZ:
  96                 tpt_table = il3945_tpt_table_g;
  97                 table_size = ARRAY_SIZE(il3945_tpt_table_g);
  98                 break;
  99         case NL80211_BAND_5GHZ:
 100                 tpt_table = il3945_tpt_table_a;
 101                 table_size = ARRAY_SIZE(il3945_tpt_table_a);
 102                 break;
 103         default:
 104                 BUG();
 105                 break;
 106         }
 107
 108         while (idx < table_size && rssi < tpt_table[idx].min_rssi)
 109                 idx++;
 110
 111         idx = min(idx, table_size - 1);
 112
 113         return tpt_table[idx].idx;
 114 }
 115
 116 static void
 117 il3945_clear_win(struct il3945_rate_scale_data *win)
 118 {
 119         win->data = 0;
 120         win->success_counter = 0;
 121         win->success_ratio = -1;
 122         win->counter = 0;
 123         win->average_tpt = IL_INVALID_VALUE;
 124         win->stamp = 0;
 125 }
 126
 127 /**
 128  * il3945_rate_scale_flush_wins - flush out the rate scale wins
 129  *
 130  * Returns the number of wins that have gathered data but were
 131  * not flushed.  If there were any that were not flushed, then
 132  * reschedule the rate flushing routine.
 133  */
 134 static int
 135 il3945_rate_scale_flush_wins(struct il3945_rs_sta *rs_sta)
 136 {
 137         int unflushed = 0;
 138         int i;
 139         unsigned long flags;
 140         struct il_priv *il __maybe_unused = rs_sta->il;
 141
 142         /*
 143          * For each rate, if we have collected data on that rate
 144          * and it has been more than RATE_WIN_FLUSH
 145          * since we flushed, clear out the gathered stats
 146          */
 147         for (i = 0; i < RATE_COUNT_3945; i++) {
 148                 if (!rs_sta->win[i].counter)
 149                         continue;
 150
 151                 spin_lock_irqsave(&rs_sta->lock, flags);
 152                 if (time_after(jiffies, rs_sta->win[i].stamp + RATE_WIN_FLUSH)) {
 153                         D_RATE("flushing %d samples of rate " "idx %d\n",
 154                                rs_sta->win[i].counter, i);
 155                         il3945_clear_win(&rs_sta->win[i]);
 156                 } else
 157                         unflushed++;
 158                 spin_unlock_irqrestore(&rs_sta->lock, flags);
 159         }
 160
 161         return unflushed;
 162 }
 163
 164 #define RATE_FLUSH_MAX              5000        /* msec */
 165 #define RATE_FLUSH_MIN              50  /* msec */
 166 #define IL_AVERAGE_PACKETS             1500
 167
 168 static void
 169 il3945_bg_rate_scale_flush(struct timer_list *t)
 170 {
 171         struct il3945_rs_sta *rs_sta = from_timer(rs_sta, t, rate_scale_flush);
 172         struct il_priv *il __maybe_unused = rs_sta->il;
 173         int unflushed = 0;
 174         unsigned long flags;
 175         u32 packet_count, duration, pps;
 176
 177         D_RATE("enter\n");
 178
 179         unflushed = il3945_rate_scale_flush_wins(rs_sta);
 180
 181         spin_lock_irqsave(&rs_sta->lock, flags);
 182
 183         /* Number of packets Rx'd since last time this timer ran */
 184         packet_count = (rs_sta->tx_packets - rs_sta->last_tx_packets) + 1;
 185
 186         rs_sta->last_tx_packets = rs_sta->tx_packets + 1;
 187
 188         if (unflushed) {
 189                 duration =
 190                     jiffies_to_msecs(jiffies - rs_sta->last_partial_flush);
 191
 192                 D_RATE("Tx'd %d packets in %dms\n", packet_count, duration);
 193
 194                 /* Determine packets per second */
 195                 if (duration)
 196                         pps = (packet_count * 1000) / duration;
 197                 else
 198                         pps = 0;
 199
 200                 if (pps) {
 201                         duration = (IL_AVERAGE_PACKETS * 1000) / pps;
 202                         if (duration < RATE_FLUSH_MIN)
 203                                 duration = RATE_FLUSH_MIN;
 204                         else if (duration > RATE_FLUSH_MAX)
 205                                 duration = RATE_FLUSH_MAX;
 206                 } else
 207                         duration = RATE_FLUSH_MAX;
 208
 209                 rs_sta->flush_time = msecs_to_jiffies(duration);
 210
 211                 D_RATE("new flush period: %d msec ave %d\n", duration,
 212                        packet_count);
 213
 214                 mod_timer(&rs_sta->rate_scale_flush,
 215                           jiffies + rs_sta->flush_time);
 216
 217                 rs_sta->last_partial_flush = jiffies;
 218         } else {
 219                 rs_sta->flush_time = RATE_FLUSH;
 220                 rs_sta->flush_pending = 0;
 221         }
 222         /* If there weren't any unflushed entries, we don't schedule the timer
 223          * to run again */
 224
 225         rs_sta->last_flush = jiffies;
 226
 227         spin_unlock_irqrestore(&rs_sta->lock, flags);
 228
 229         D_RATE("leave\n");
 230 }
 231
 232 /**
 233  * il3945_collect_tx_data - Update the success/failure sliding win
 234  *
 235  * We keep a sliding win of the last 64 packets transmitted
 236  * at this rate.  win->data contains the bitmask of successful
 237  * packets.
 238  */
 239 static void
 240 il3945_collect_tx_data(struct il3945_rs_sta *rs_sta,
 241                        struct il3945_rate_scale_data *win, int success,
 242                        int retries, int idx)
 243 {
 244         unsigned long flags;
 245         s32 fail_count;
 246         struct il_priv *il __maybe_unused = rs_sta->il;
 247
 248         if (!retries) {
 249                 D_RATE("leave: retries == 0 -- should be at least 1\n");
 250                 return;
 251         }
 252
 253         spin_lock_irqsave(&rs_sta->lock, flags);
 254
 255         /*
 256          * Keep track of only the latest 62 tx frame attempts in this rate's
 257          * history win; anything older isn't really relevant any more.
 258          * If we have filled up the sliding win, drop the oldest attempt;
 259          * if the oldest attempt (highest bit in bitmap) shows "success",
 260          * subtract "1" from the success counter (this is the main reason
 261          * we keep these bitmaps!).
 262          * */
 263         while (retries > 0) {
 264                 if (win->counter >= RATE_MAX_WINDOW) {
 265
 266                         /* remove earliest */
 267                         win->counter = RATE_MAX_WINDOW - 1;
 268
 269                         if (win->data & (1ULL << (RATE_MAX_WINDOW - 1))) {
 270                                 win->data &= ~(1ULL << (RATE_MAX_WINDOW - 1));
 271                                 win->success_counter--;
 272                         }
 273                 }
 274
 275                 /* Increment frames-attempted counter */
 276                 win->counter++;
 277
 278                 /* Shift bitmap by one frame (throw away oldest history),
 279                  * OR in "1", and increment "success" if this
 280                  * frame was successful. */
 281                 win->data <<= 1;
 282                 if (success > 0) {
 283                         win->success_counter++;
 284                         win->data |= 0x1;
 285                         success--;
 286                 }
 287
 288                 retries--;
 289         }
 290
 291         /* Calculate current success ratio, avoid divide-by-0! */
 292         if (win->counter > 0)
 293                 win->success_ratio =
 294                     128 * (100 * win->success_counter) / win->counter;
 295         else
 296                 win->success_ratio = IL_INVALID_VALUE;
 297
 298         fail_count = win->counter - win->success_counter;
 299
 300         /* Calculate average throughput, if we have enough history. */
 301         if (fail_count >= RATE_MIN_FAILURE_TH ||
 302             win->success_counter >= RATE_MIN_SUCCESS_TH)
 303                 win->average_tpt =
 304                     ((win->success_ratio * rs_sta->expected_tpt[idx] +
 305                       64) / 128);
 306         else
 307                 win->average_tpt = IL_INVALID_VALUE;
 308
 309         /* Tag this win as having been updated */
 310         win->stamp = jiffies;
 311
 312         spin_unlock_irqrestore(&rs_sta->lock, flags);
 313 }
 314
 315 /*
 316  * Called after adding a new station to initialize rate scaling
 317  */
 318 void
 319 il3945_rs_rate_init(struct il_priv *il, struct ieee80211_sta *sta, u8 sta_id)
 320 {
 321         struct ieee80211_hw *hw = il->hw;
 322         struct ieee80211_conf *conf = &il->hw->conf;
 323         struct il3945_sta_priv *psta;
 324         struct il3945_rs_sta *rs_sta;
 325         struct ieee80211_supported_band *sband;
 326         int i;
 327
 328         D_INFO("enter\n");
 329         if (sta_id == il->hw_params.bcast_id)
 330                 goto out;
 331
 332         psta = (struct il3945_sta_priv *)sta->drv_priv;
 333         rs_sta = &psta->rs_sta;
 334         sband = hw->wiphy->bands[conf->chandef.chan->band];
 335
 336         rs_sta->il = il;
 337
 338         rs_sta->start_rate = RATE_INVALID;
 339
 340         /* default to just 802.11b */
 341         rs_sta->expected_tpt = il3945_expected_tpt_b;
 342
 343         rs_sta->last_partial_flush = jiffies;
 344         rs_sta->last_flush = jiffies;
 345         rs_sta->flush_time = RATE_FLUSH;
 346         rs_sta->last_tx_packets = 0;
 347
 348         for (i = 0; i < RATE_COUNT_3945; i++)
 349                 il3945_clear_win(&rs_sta->win[i]);
 350
 351         /* TODO: what is a good starting rate for STA? About middle? Maybe not
 352          * the lowest or the highest rate.. Could consider using RSSI from
 353          * previous packets? Need to have IEEE 802.1X auth succeed immediately
 354          * after assoc.. */
 355
 356         for (i = sband->n_bitrates - 1; i >= 0; i--) {
 357                 if (sta->supp_rates[sband->band] & (1 << i)) {
 358                         rs_sta->last_txrate_idx = i;
 359                         break;
 360                 }
 361         }
 362
 363         il->_3945.sta_supp_rates = sta->supp_rates[sband->band];
 364         /* For 5 GHz band it start at IL_FIRST_OFDM_RATE */
 365         if (sband->band == NL80211_BAND_5GHZ) {
 366                 rs_sta->last_txrate_idx += IL_FIRST_OFDM_RATE;
 367                 il->_3945.sta_supp_rates <<= IL_FIRST_OFDM_RATE;
 368         }
 369
 370 out:
 371         il->stations[sta_id].used &= ~IL_STA_UCODE_INPROGRESS;
 372
 373         D_INFO("leave\n");
 374 }
 375
 376 static void *
 377 il3945_rs_alloc(struct ieee80211_hw *hw)
 378 {
 379         return hw->priv;
 380 }
 381
 382 /* rate scale requires free function to be implemented */
 383 static void
 384 il3945_rs_free(void *il)
 385 {
 386 }
 387
 388 static void *
 389 il3945_rs_alloc_sta(void *il_priv, struct ieee80211_sta *sta, gfp_t gfp)
 390 {
 391         struct il3945_rs_sta *rs_sta;
 392         struct il3945_sta_priv *psta = (void *)sta->drv_priv;
 393         struct il_priv *il __maybe_unused = il_priv;
 394
 395         D_RATE("enter\n");
 396
 397         rs_sta = &psta->rs_sta;
 398
 399         spin_lock_init(&rs_sta->lock);
 400         timer_setup(&rs_sta->rate_scale_flush, il3945_bg_rate_scale_flush, 0);
 401         D_RATE("leave\n");
 402
 403         return rs_sta;
 404 }
 405
 406 static void
 407 il3945_rs_free_sta(void *il_priv, struct ieee80211_sta *sta, void *il_sta)
 408 {
 409         struct il3945_rs_sta *rs_sta = il_sta;
 410
 411         /*
 412          * Be careful not to use any members of il3945_rs_sta (like trying
 413          * to use il_priv to print out debugging) since it may not be fully
 414          * initialized at this point.
 415          */
 416         del_timer_sync(&rs_sta->rate_scale_flush);
 417 }
 418
 419 /**
 420  * il3945_rs_tx_status - Update rate control values based on Tx results
 421  *
 422  * NOTE: Uses il_priv->retry_rate for the # of retries attempted by
 423  * the hardware for each rate.
 424  */
 425 static void
 426 il3945_rs_tx_status(void *il_rate, struct ieee80211_supported_band *sband,
 427                     struct ieee80211_sta *sta, void *il_sta,
 428                     struct sk_buff *skb)
 429 {
 430         s8 retries = 0, current_count;
 431         int scale_rate_idx, first_idx, last_idx;
 432         unsigned long flags;
 433         struct il_priv *il = (struct il_priv *)il_rate;
 434         struct il3945_rs_sta *rs_sta = il_sta;
 435         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 436
 437         D_RATE("enter\n");
 438
 439         retries = info->status.rates[0].count;
 440         /* Sanity Check for retries */
 441         if (retries > RATE_RETRY_TH)
 442                 retries = RATE_RETRY_TH;
 443
 444         first_idx = sband->bitrates[info->status.rates[0].idx].hw_value;
 445         if (first_idx < 0 || first_idx >= RATE_COUNT_3945) {
 446                 D_RATE("leave: Rate out of bounds: %d\n", first_idx);
 447                 return;
 448         }
 449
 450         if (!il_sta) {
 451                 D_RATE("leave: No STA il data to update!\n");
 452                 return;
 453         }
 454
 455         /* Treat uninitialized rate scaling data same as non-existing. */
 456         if (!rs_sta->il) {
 457                 D_RATE("leave: STA il data uninitialized!\n");
 458                 return;
 459         }
 460
 461         rs_sta->tx_packets++;
 462
 463         scale_rate_idx = first_idx;
 464         last_idx = first_idx;
 465
 466         /*
 467          * Update the win for each rate.  We determine which rates
 468          * were Tx'd based on the total number of retries vs. the number
 469          * of retries configured for each rate -- currently set to the
 470          * il value 'retry_rate' vs. rate specific
 471          *
 472          * On exit from this while loop last_idx indicates the rate
 473          * at which the frame was finally transmitted (or failed if no
 474          * ACK)
 475          */
 476         while (retries > 1) {
 477                 if ((retries - 1) < il->retry_rate) {
 478                         current_count = (retries - 1);
 479                         last_idx = scale_rate_idx;
 480                 } else {
 481                         current_count = il->retry_rate;
 482                         last_idx = il3945_rs_next_rate(il, scale_rate_idx);
 483                 }
 484
 485                 /* Update this rate accounting for as many retries
 486                  * as was used for it (per current_count) */
 487                 il3945_collect_tx_data(rs_sta, &rs_sta->win[scale_rate_idx], 0,
 488                                        current_count, scale_rate_idx);
 489                 D_RATE("Update rate %d for %d retries.\n", scale_rate_idx,
 490                        current_count);
 491
 492                 retries -= current_count;
 493
 494                 scale_rate_idx = last_idx;
 495         }
 496
 497         /* Update the last idx win with success/failure based on ACK */
 498         D_RATE("Update rate %d with %s.\n", last_idx,
 499                (info->flags & IEEE80211_TX_STAT_ACK) ? "success" : "failure");
 500         il3945_collect_tx_data(rs_sta, &rs_sta->win[last_idx],
 501                                info->flags & IEEE80211_TX_STAT_ACK, 1,
 502                                last_idx);
 503
 504         /* We updated the rate scale win -- if its been more than
 505          * flush_time since the last run, schedule the flush
 506          * again */
 507         spin_lock_irqsave(&rs_sta->lock, flags);
 508
 509         if (!rs_sta->flush_pending &&
 510             time_after(jiffies, rs_sta->last_flush + rs_sta->flush_time)) {
 511
 512                 rs_sta->last_partial_flush = jiffies;
 513                 rs_sta->flush_pending = 1;
 514                 mod_timer(&rs_sta->rate_scale_flush,
 515                           jiffies + rs_sta->flush_time);
 516         }
 517
 518         spin_unlock_irqrestore(&rs_sta->lock, flags);
 519
 520         D_RATE("leave\n");
 521 }
 522
 523 static u16
 524 il3945_get_adjacent_rate(struct il3945_rs_sta *rs_sta, u8 idx, u16 rate_mask,
 525                          enum nl80211_band band)
 526 {
 527         u8 high = RATE_INVALID;
 528         u8 low = RATE_INVALID;
 529         struct il_priv *il __maybe_unused = rs_sta->il;
 530
 531         /* 802.11A walks to the next literal adjacent rate in
 532          * the rate table */
 533         if (unlikely(band == NL80211_BAND_5GHZ)) {
 534                 int i;
 535                 u32 mask;
 536
 537                 /* Find the previous rate that is in the rate mask */
 538                 i = idx - 1;
 539                 for (mask = (1 << i); i >= 0; i--, mask >>= 1) {
 540                         if (rate_mask & mask) {
 541                                 low = i;
 542                                 break;
 543                         }
 544                 }
 545
 546                 /* Find the next rate that is in the rate mask */
 547                 i = idx + 1;
 548                 for (mask = (1 << i); i < RATE_COUNT_3945; i++, mask <<= 1) {
 549                         if (rate_mask & mask) {
 550                                 high = i;
 551                                 break;
 552                         }
 553                 }
 554
 555                 return (high << 8) | low;
 556         }
 557
 558         low = idx;
 559         while (low != RATE_INVALID) {
 560                 if (rs_sta->tgg)
 561                         low = il3945_rates[low].prev_rs_tgg;
 562                 else
 563                         low = il3945_rates[low].prev_rs;
 564                 if (low == RATE_INVALID)
 565                         break;
 566                 if (rate_mask & (1 << low))
 567                         break;
 568                 D_RATE("Skipping masked lower rate: %d\n", low);
 569         }
 570
 571         high = idx;
 572         while (high != RATE_INVALID) {
 573                 if (rs_sta->tgg)
 574                         high = il3945_rates[high].next_rs_tgg;
 575                 else
 576                         high = il3945_rates[high].next_rs;
 577                 if (high == RATE_INVALID)
 578                         break;
 579                 if (rate_mask & (1 << high))
 580                         break;
 581                 D_RATE("Skipping masked higher rate: %d\n", high);
 582         }
 583
 584         return (high << 8) | low;
 585 }
 586
 587 /**
 588  * il3945_rs_get_rate - find the rate for the requested packet
 589  *
 590  * Returns the ieee80211_rate structure allocated by the driver.
 591  *
 592  * The rate control algorithm has no internal mapping between hw_mode's
 593  * rate ordering and the rate ordering used by the rate control algorithm.
 594  *
 595  * The rate control algorithm uses a single table of rates that goes across
 596  * the entire A/B/G spectrum vs. being limited to just one particular
 597  * hw_mode.
 598  *
 599  * As such, we can't convert the idx obtained below into the hw_mode's
 600  * rate table and must reference the driver allocated rate table
 601  *
 602  */
 603 static void
 604 il3945_rs_get_rate(void *il_r, struct ieee80211_sta *sta, void *il_sta,
 605                    struct ieee80211_tx_rate_control *txrc)
 606 {
 607         struct ieee80211_supported_band *sband = txrc->sband;
 608         struct sk_buff *skb = txrc->skb;
 609         u8 low = RATE_INVALID;
 610         u8 high = RATE_INVALID;
 611         u16 high_low;
 612         int idx;
 613         struct il3945_rs_sta *rs_sta = il_sta;
 614         struct il3945_rate_scale_data *win = NULL;
 615         int current_tpt = IL_INVALID_VALUE;
 616         int low_tpt = IL_INVALID_VALUE;
 617         int high_tpt = IL_INVALID_VALUE;
 618         u32 fail_count;
 619         s8 scale_action = 0;
 620         unsigned long flags;
 621         u16 rate_mask;
 622         s8 max_rate_idx = -1;
 623         struct il_priv *il __maybe_unused = (struct il_priv *)il_r;
 624         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 625
 626         D_RATE("enter\n");
 627
 628         /* Treat uninitialized rate scaling data same as non-existing. */
 629         if (rs_sta && !rs_sta->il) {
 630                 D_RATE("Rate scaling information not initialized yet.\n");
 631                 il_sta = NULL;
 632         }
 633
 634         rate_mask = sta->supp_rates[sband->band];
 635
 636         /* get user max rate if set */
 637         max_rate_idx = fls(txrc->rate_idx_mask) - 1;
 638         if (sband->band == NL80211_BAND_5GHZ && max_rate_idx != -1)
 639                 max_rate_idx += IL_FIRST_OFDM_RATE;
 640         if (max_rate_idx < 0 || max_rate_idx >= RATE_COUNT)
 641                 max_rate_idx = -1;
 642
 643         idx = min(rs_sta->last_txrate_idx & 0xffff, RATE_COUNT_3945 - 1);
 644
 645         if (sband->band == NL80211_BAND_5GHZ)
 646                 rate_mask = rate_mask << IL_FIRST_OFDM_RATE;
 647
 648         spin_lock_irqsave(&rs_sta->lock, flags);
 649
 650         /* for recent assoc, choose best rate regarding
 651          * to rssi value
 652          */
 653         if (rs_sta->start_rate != RATE_INVALID) {
 654                 if (rs_sta->start_rate < idx &&
 655                     (rate_mask & (1 << rs_sta->start_rate)))
 656                         idx = rs_sta->start_rate;
 657                 rs_sta->start_rate = RATE_INVALID;
 658         }
 659
 660         /* force user max rate if set by user */
 661         if (max_rate_idx != -1 && max_rate_idx < idx) {
 662                 if (rate_mask & (1 << max_rate_idx))
 663                         idx = max_rate_idx;
 664         }
 665
 666         win = &(rs_sta->win[idx]);
 667
 668         fail_count = win->counter - win->success_counter;
 669
 670         if (fail_count < RATE_MIN_FAILURE_TH &&
 671             win->success_counter < RATE_MIN_SUCCESS_TH) {
 672                 spin_unlock_irqrestore(&rs_sta->lock, flags);
 673
 674                 D_RATE("Invalid average_tpt on rate %d: "
 675                        "counter: %d, success_counter: %d, "
 676                        "expected_tpt is %sNULL\n", idx, win->counter,
 677                        win->success_counter,
 678                        rs_sta->expected_tpt ? "not " : "");
 679
 680                 /* Can't calculate this yet; not enough history */
 681                 win->average_tpt = IL_INVALID_VALUE;
 682                 goto out;
 683
 684         }
 685
 686         current_tpt = win->average_tpt;
 687
 688         high_low =
 689             il3945_get_adjacent_rate(rs_sta, idx, rate_mask, sband->band);
 690         low = high_low & 0xff;
 691         high = (high_low >> 8) & 0xff;
 692
 693         /* If user set max rate, dont allow higher than user constrain */
 694         if (max_rate_idx != -1 && max_rate_idx < high)
 695                 high = RATE_INVALID;
 696
 697         /* Collect Measured throughputs of adjacent rates */
 698         if (low != RATE_INVALID)
 699                 low_tpt = rs_sta->win[low].average_tpt;
 700
 701         if (high != RATE_INVALID)
 702                 high_tpt = rs_sta->win[high].average_tpt;
 703
 704         spin_unlock_irqrestore(&rs_sta->lock, flags);
 705
 706         scale_action = 0;
 707
 708         /* Low success ratio , need to drop the rate */
 709         if (win->success_ratio < RATE_DECREASE_TH || !current_tpt) {
 710                 D_RATE("decrease rate because of low success_ratio\n");
 711                 scale_action = -1;
 712                 /* No throughput measured yet for adjacent rates,
 713                  * try increase */
 714         } else if (low_tpt == IL_INVALID_VALUE && high_tpt == IL_INVALID_VALUE) {
 715
 716                 if (high != RATE_INVALID &&
 717                     win->success_ratio >= RATE_INCREASE_TH)
 718                         scale_action = 1;
 719                 else if (low != RATE_INVALID)
 720                         scale_action = 0;
 721
 722                 /* Both adjacent throughputs are measured, but neither one has
 723                  * better throughput; we're using the best rate, don't change
 724                  * it! */
 725         } else if (low_tpt != IL_INVALID_VALUE && high_tpt != IL_INVALID_VALUE
 726                    && low_tpt < current_tpt && high_tpt < current_tpt) {
 727
 728                 D_RATE("No action -- low [%d] & high [%d] < "
 729                        "current_tpt [%d]\n", low_tpt, high_tpt, current_tpt);
 730                 scale_action = 0;
 731
 732                 /* At least one of the rates has better throughput */
 733         } else {
 734                 if (high_tpt != IL_INVALID_VALUE) {
 735
 736                         /* High rate has better throughput, Increase
 737                          * rate */
 738                         if (high_tpt > current_tpt &&
 739                             win->success_ratio >= RATE_INCREASE_TH)
 740                                 scale_action = 1;
 741                         else {
 742                                 D_RATE("decrease rate because of high tpt\n");
 743                                 scale_action = 0;
 744                         }
 745                 } else if (low_tpt != IL_INVALID_VALUE) {
 746                         if (low_tpt > current_tpt) {
 747                                 D_RATE("decrease rate because of low tpt\n");
 748                                 scale_action = -1;
 749                         } else if (win->success_ratio >= RATE_INCREASE_TH) {
 750                                 /* Lower rate has better
 751                                  * throughput,decrease rate */
 752                                 scale_action = 1;
 753                         }
 754                 }
 755         }
 756
 757         /* Sanity check; asked for decrease, but success rate or throughput
 758          * has been good at old rate.  Don't change it. */
 759         if (scale_action == -1 && low != RATE_INVALID &&
 760             (win->success_ratio > RATE_HIGH_TH ||
 761              current_tpt > 100 * rs_sta->expected_tpt[low]))
 762                 scale_action = 0;
 763
 764         switch (scale_action) {
 765         case -1:
 766                 /* Decrease rate */
 767                 if (low != RATE_INVALID)
 768                         idx = low;
 769                 break;
 770         case 1:
 771                 /* Increase rate */
 772                 if (high != RATE_INVALID)
 773                         idx = high;
 774
 775                 break;
 776         case 0:
 777         default:
 778                 /* No change */
 779                 break;
 780         }
 781
 782         D_RATE("Selected %d (action %d) - low %d high %d\n", idx, scale_action,
 783                low, high);
 784
 785 out:
 786
 787         if (sband->band == NL80211_BAND_5GHZ) {
 788                 if (WARN_ON_ONCE(idx < IL_FIRST_OFDM_RATE))
 789                         idx = IL_FIRST_OFDM_RATE;
 790                 rs_sta->last_txrate_idx = idx;
 791                 info->control.rates[0].idx = idx - IL_FIRST_OFDM_RATE;
 792         } else {
 793                 rs_sta->last_txrate_idx = idx;
 794                 info->control.rates[0].idx = rs_sta->last_txrate_idx;
 795         }
 796         info->control.rates[0].count = 1;
 797
 798         D_RATE("leave: %d\n", idx);
 799 }
 800
 801 #ifdef CONFIG_MAC80211_DEBUGFS
 802
 803 static ssize_t
 804 il3945_sta_dbgfs_stats_table_read(struct file *file, char __user *user_buf,
 805                                   size_t count, loff_t *ppos)
 806 {
 807         char *buff;
 808         int desc = 0;
 809         int j;
 810         ssize_t ret;
 811         struct il3945_rs_sta *lq_sta = file->private_data;
 812
 813         buff = kmalloc(1024, GFP_KERNEL);
 814         if (!buff)
 815                 return -ENOMEM;
 816
 817         desc +=
 818             sprintf(buff + desc,
 819                     "tx packets=%d last rate idx=%d\n"
 820                     "rate=0x%X flush time %d\n", lq_sta->tx_packets,
 821                     lq_sta->last_txrate_idx, lq_sta->start_rate,
 822                     jiffies_to_msecs(lq_sta->flush_time));
 823         for (j = 0; j < RATE_COUNT_3945; j++) {
 824                 desc +=
 825                     sprintf(buff + desc, "counter=%d success=%d %%=%d\n",
 826                             lq_sta->win[j].counter,
 827                             lq_sta->win[j].success_counter,
 828                             lq_sta->win[j].success_ratio);
 829         }
 830         ret = simple_read_from_buffer(user_buf, count, ppos, buff, desc);
 831         kfree(buff);
 832         return ret;
 833 }
 834
 835 static const struct file_operations rs_sta_dbgfs_stats_table_ops = {
 836         .read = il3945_sta_dbgfs_stats_table_read,
 837         .open = simple_open,
 838         .llseek = default_llseek,
 839 };
 840
 841 static void
 842 il3945_add_debugfs(void *il, void *il_sta, struct dentry *dir)
 843 {
 844         struct il3945_rs_sta *lq_sta = il_sta;
 845
 846         debugfs_create_file("rate_stats_table", 0600, dir, lq_sta,
 847                             &rs_sta_dbgfs_stats_table_ops);
 848 }
 849 #endif
 850
 851 /*
 852  * Initialization of rate scaling information is done by driver after
 853  * the station is added. Since mac80211 calls this function before a
 854  * station is added we ignore it.
 855  */
 856 static void
 857 il3945_rs_rate_init_stub(void *il_r, struct ieee80211_supported_band *sband,
 858                          struct cfg80211_chan_def *chandef,
 859                          struct ieee80211_sta *sta, void *il_sta)
 860 {
 861 }
 862
 863 static const struct rate_control_ops rs_ops = {
 864         .name = RS_NAME,
 865         .tx_status = il3945_rs_tx_status,
 866         .get_rate = il3945_rs_get_rate,
 867         .rate_init = il3945_rs_rate_init_stub,
 868         .alloc = il3945_rs_alloc,
 869         .free = il3945_rs_free,
 870         .alloc_sta = il3945_rs_alloc_sta,
 871         .free_sta = il3945_rs_free_sta,
 872 #ifdef CONFIG_MAC80211_DEBUGFS
 873         .add_sta_debugfs = il3945_add_debugfs,
 874 #endif
 875
 876 };
 877
 878 void
 879 il3945_rate_scale_init(struct ieee80211_hw *hw, s32 sta_id)
 880 {
 881         struct il_priv *il = hw->priv;
 882         s32 rssi = 0;
 883         unsigned long flags;
 884         struct il3945_rs_sta *rs_sta;
 885         struct ieee80211_sta *sta;
 886         struct il3945_sta_priv *psta;
 887
 888         D_RATE("enter\n");
 889
 890         rcu_read_lock();
 891
 892         sta = ieee80211_find_sta(il->vif, il->stations[sta_id].sta.sta.addr);
 893         if (!sta) {
 894                 D_RATE("Unable to find station to initialize rate scaling.\n");
 895                 rcu_read_unlock();
 896                 return;
 897         }
 898
 899         psta = (void *)sta->drv_priv;
 900         rs_sta = &psta->rs_sta;
 901
 902         spin_lock_irqsave(&rs_sta->lock, flags);
 903
 904         rs_sta->tgg = 0;
 905         switch (il->band) {
 906         case NL80211_BAND_2GHZ:
 907                 /* TODO: this always does G, not a regression */
 908                 if (il->active.flags & RXON_FLG_TGG_PROTECT_MSK) {
 909                         rs_sta->tgg = 1;
 910                         rs_sta->expected_tpt = il3945_expected_tpt_g_prot;
 911                 } else
 912                         rs_sta->expected_tpt = il3945_expected_tpt_g;
 913                 break;
 914         case NL80211_BAND_5GHZ:
 915                 rs_sta->expected_tpt = il3945_expected_tpt_a;
 916                 break;
 917         default:
 918                 BUG();
 919                 break;
 920         }
 921
 922         spin_unlock_irqrestore(&rs_sta->lock, flags);
 923
 924         rssi = il->_3945.last_rx_rssi;
 925         if (rssi == 0)
 926                 rssi = IL_MIN_RSSI_VAL;
 927
 928         D_RATE("Network RSSI: %d\n", rssi);
 929
 930         rs_sta->start_rate = il3945_get_rate_idx_by_rssi(rssi, il->band);
 931
 932         D_RATE("leave: rssi %d assign rate idx: " "%d (plcp 0x%x)\n", rssi,
 933                rs_sta->start_rate, il3945_rates[rs_sta->start_rate].plcp);
 934         rcu_read_unlock();
 935 }
 936
 937 int
 938 il3945_rate_control_register(void)
 939 {
 940         return ieee80211_rate_control_register(&rs_ops);
 941 }
 942
 943 void
 944 il3945_rate_control_unregister(void)
 945 {
 946         ieee80211_rate_control_unregister(&rs_ops);
 947 }