drivers/net/wireless/iwlegacy/iwl-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 <linux/wireless.h>
  32 #include <net/mac80211.h>
  33
  34 #include <linux/netdevice.h>
  35 #include <linux/etherdevice.h>
  36 #include <linux/delay.h>
  37
  38 #include <linux/workqueue.h>
  39
  40 #include "iwl-commands.h"
  41 #include "iwl-3945.h"
  42 #include "iwl-sta.h"
  43
  44 #define RS_NAME "iwl-3945-rs"
  45
  46 static s32 iwl3945_expected_tpt_g[IWL_RATE_COUNT_3945] = {
  47         7, 13, 35, 58, 0, 0, 76, 104, 130, 168, 191, 202
  48 };
  49
  50 static s32 iwl3945_expected_tpt_g_prot[IWL_RATE_COUNT_3945] = {
  51         7, 13, 35, 58, 0, 0, 0, 80, 93, 113, 123, 125
  52 };
  53
  54 static s32 iwl3945_expected_tpt_a[IWL_RATE_COUNT_3945] = {
  55         0, 0, 0, 0, 40, 57, 72, 98, 121, 154, 177, 186
  56 };
  57
  58 static s32 iwl3945_expected_tpt_b[IWL_RATE_COUNT_3945] = {
  59         7, 13, 35, 58, 0, 0, 0, 0, 0, 0, 0, 0
  60 };
  61
  62 struct iwl3945_tpt_entry {
  63         s8 min_rssi;
  64         u8 index;
  65 };
  66
  67 static struct iwl3945_tpt_entry iwl3945_tpt_table_a[] = {
  68         {-60, IWL_RATE_54M_INDEX},
  69         {-64, IWL_RATE_48M_INDEX},
  70         {-72, IWL_RATE_36M_INDEX},
  71         {-80, IWL_RATE_24M_INDEX},
  72         {-84, IWL_RATE_18M_INDEX},
  73         {-85, IWL_RATE_12M_INDEX},
  74         {-87, IWL_RATE_9M_INDEX},
  75         {-89, IWL_RATE_6M_INDEX}
  76 };
  77
  78 static struct iwl3945_tpt_entry iwl3945_tpt_table_g[] = {
  79         {-60, IWL_RATE_54M_INDEX},
  80         {-64, IWL_RATE_48M_INDEX},
  81         {-68, IWL_RATE_36M_INDEX},
  82         {-80, IWL_RATE_24M_INDEX},
  83         {-84, IWL_RATE_18M_INDEX},
  84         {-85, IWL_RATE_12M_INDEX},
  85         {-86, IWL_RATE_11M_INDEX},
  86         {-88, IWL_RATE_5M_INDEX},
  87         {-90, IWL_RATE_2M_INDEX},
  88         {-92, IWL_RATE_1M_INDEX}
  89 };
  90
  91 #define IWL_RATE_MAX_WINDOW          62
  92 #define IWL_RATE_FLUSH          (3*HZ)
  93 #define IWL_RATE_WIN_FLUSH       (HZ/2)
  94 #define IWL39_RATE_HIGH_TH          11520
  95 #define IWL_SUCCESS_UP_TH          8960
  96 #define IWL_SUCCESS_DOWN_TH       10880
  97 #define IWL_RATE_MIN_FAILURE_TH       6
  98 #define IWL_RATE_MIN_SUCCESS_TH       8
  99 #define IWL_RATE_DECREASE_TH       1920
 100 #define IWL_RATE_RETRY_TH            15
 101
 102 static u8 iwl3945_get_rate_index_by_rssi(s32 rssi, enum ieee80211_band band)
 103 {
 104         u32 index = 0;
 105         u32 table_size = 0;
 106         struct iwl3945_tpt_entry *tpt_table = NULL;
 107
 108         if ((rssi < IWL_MIN_RSSI_VAL) || (rssi > IWL_MAX_RSSI_VAL))
 109                 rssi = IWL_MIN_RSSI_VAL;
 110
 111         switch (band) {
 112         case IEEE80211_BAND_2GHZ:
 113                 tpt_table = iwl3945_tpt_table_g;
 114                 table_size = ARRAY_SIZE(iwl3945_tpt_table_g);
 115                 break;
 116
 117         case IEEE80211_BAND_5GHZ:
 118                 tpt_table = iwl3945_tpt_table_a;
 119                 table_size = ARRAY_SIZE(iwl3945_tpt_table_a);
 120                 break;
 121
 122         default:
 123                 BUG();
 124                 break;
 125         }
 126
 127         while ((index < table_size) && (rssi < tpt_table[index].min_rssi))
 128                 index++;
 129
 130         index = min(index, (table_size - 1));
 131
 132         return tpt_table[index].index;
 133 }
 134
 135 static void iwl3945_clear_window(struct iwl3945_rate_scale_data *window)
 136 {
 137         window->data = 0;
 138         window->success_counter = 0;
 139         window->success_ratio = -1;
 140         window->counter = 0;
 141         window->average_tpt = IWL_INVALID_VALUE;
 142         window->stamp = 0;
 143 }
 144
 145 /**
 146  * iwl3945_rate_scale_flush_windows - flush out the rate scale windows
 147  *
 148  * Returns the number of windows that have gathered data but were
 149  * not flushed.  If there were any that were not flushed, then
 150  * reschedule the rate flushing routine.
 151  */
 152 static int iwl3945_rate_scale_flush_windows(struct iwl3945_rs_sta *rs_sta)
 153 {
 154         int unflushed = 0;
 155         int i;
 156         unsigned long flags;
 157         struct iwl_priv *priv __maybe_unused = rs_sta->priv;
 158
 159         /*
 160          * For each rate, if we have collected data on that rate
 161          * and it has been more than IWL_RATE_WIN_FLUSH
 162          * since we flushed, clear out the gathered statistics
 163          */
 164         for (i = 0; i < IWL_RATE_COUNT_3945; i++) {
 165                 if (!rs_sta->win[i].counter)
 166                         continue;
 167
 168                 spin_lock_irqsave(&rs_sta->lock, flags);
 169                 if (time_after(jiffies, rs_sta->win[i].stamp +
 170                                IWL_RATE_WIN_FLUSH)) {
 171                         IWL_DEBUG_RATE(priv, "flushing %d samples of rate "
 172                                        "index %d\n",
 173                                        rs_sta->win[i].counter, i);
 174                         iwl3945_clear_window(&rs_sta->win[i]);
 175                 } else
 176                         unflushed++;
 177                 spin_unlock_irqrestore(&rs_sta->lock, flags);
 178         }
 179
 180         return unflushed;
 181 }
 182
 183 #define IWL_RATE_FLUSH_MAX              5000    /* msec */
 184 #define IWL_RATE_FLUSH_MIN              50      /* msec */
 185 #define IWL_AVERAGE_PACKETS             1500
 186
 187 static void iwl3945_bg_rate_scale_flush(unsigned long data)
 188 {
 189         struct iwl3945_rs_sta *rs_sta = (void *)data;
 190         struct iwl_priv *priv __maybe_unused = rs_sta->priv;
 191         int unflushed = 0;
 192         unsigned long flags;
 193         u32 packet_count, duration, pps;
 194
 195         IWL_DEBUG_RATE(priv, "enter\n");
 196
 197         unflushed = iwl3945_rate_scale_flush_windows(rs_sta);
 198
 199         spin_lock_irqsave(&rs_sta->lock, flags);
 200
 201         /* Number of packets Rx'd since last time this timer ran */
 202         packet_count = (rs_sta->tx_packets - rs_sta->last_tx_packets) + 1;
 203
 204         rs_sta->last_tx_packets = rs_sta->tx_packets + 1;
 205
 206         if (unflushed) {
 207                 duration =
 208                     jiffies_to_msecs(jiffies - rs_sta->last_partial_flush);
 209
 210                 IWL_DEBUG_RATE(priv, "Tx'd %d packets in %dms\n",
 211                                packet_count, duration);
 212
 213                 /* Determine packets per second */
 214                 if (duration)
 215                         pps = (packet_count * 1000) / duration;
 216                 else
 217                         pps = 0;
 218
 219                 if (pps) {
 220                         duration = (IWL_AVERAGE_PACKETS * 1000) / pps;
 221                         if (duration < IWL_RATE_FLUSH_MIN)
 222                                 duration = IWL_RATE_FLUSH_MIN;
 223                         else if (duration > IWL_RATE_FLUSH_MAX)
 224                                 duration = IWL_RATE_FLUSH_MAX;
 225                 } else
 226                         duration = IWL_RATE_FLUSH_MAX;
 227
 228                 rs_sta->flush_time = msecs_to_jiffies(duration);
 229
 230                 IWL_DEBUG_RATE(priv, "new flush period: %d msec ave %d\n",
 231                                duration, packet_count);
 232
 233                 mod_timer(&rs_sta->rate_scale_flush, jiffies +
 234                           rs_sta->flush_time);
 235
 236                 rs_sta->last_partial_flush = jiffies;
 237         } else {
 238                 rs_sta->flush_time = IWL_RATE_FLUSH;
 239                 rs_sta->flush_pending = 0;
 240         }
 241         /* If there weren't any unflushed entries, we don't schedule the timer
 242          * to run again */
 243
 244         rs_sta->last_flush = jiffies;
 245
 246         spin_unlock_irqrestore(&rs_sta->lock, flags);
 247
 248         IWL_DEBUG_RATE(priv, "leave\n");
 249 }
 250
 251 /**
 252  * iwl3945_collect_tx_data - Update the success/failure sliding window
 253  *
 254  * We keep a sliding window of the last 64 packets transmitted
 255  * at this rate.  window->data contains the bitmask of successful
 256  * packets.
 257  */
 258 static void iwl3945_collect_tx_data(struct iwl3945_rs_sta *rs_sta,
 259                                 struct iwl3945_rate_scale_data *window,
 260                                 int success, int retries, int index)
 261 {
 262         unsigned long flags;
 263         s32 fail_count;
 264         struct iwl_priv *priv __maybe_unused = rs_sta->priv;
 265
 266         if (!retries) {
 267                 IWL_DEBUG_RATE(priv, "leave: retries == 0 -- should be at least 1\n");
 268                 return;
 269         }
 270
 271         spin_lock_irqsave(&rs_sta->lock, flags);
 272
 273         /*
 274          * Keep track of only the latest 62 tx frame attempts in this rate's
 275          * history window; anything older isn't really relevant any more.
 276          * If we have filled up the sliding window, drop the oldest attempt;
 277          * if the oldest attempt (highest bit in bitmap) shows "success",
 278          * subtract "1" from the success counter (this is the main reason
 279          * we keep these bitmaps!).
 280          * */
 281         while (retries > 0) {
 282                 if (window->counter >= IWL_RATE_MAX_WINDOW) {
 283
 284                         /* remove earliest */
 285                         window->counter = IWL_RATE_MAX_WINDOW - 1;
 286
 287                         if (window->data & (1ULL << (IWL_RATE_MAX_WINDOW - 1))) {
 288                                 window->data &= ~(1ULL << (IWL_RATE_MAX_WINDOW - 1));
 289                                 window->success_counter--;
 290                         }
 291                 }
 292
 293                 /* Increment frames-attempted counter */
 294                 window->counter++;
 295
 296                 /* Shift bitmap by one frame (throw away oldest history),
 297                  * OR in "1", and increment "success" if this
 298                  * frame was successful. */
 299                 window->data <<= 1;
 300                 if (success > 0) {
 301                         window->success_counter++;
 302                         window->data |= 0x1;
 303                         success--;
 304                 }
 305
 306                 retries--;
 307         }
 308
 309         /* Calculate current success ratio, avoid divide-by-0! */
 310         if (window->counter > 0)
 311                 window->success_ratio = 128 * (100 * window->success_counter)
 312                                         / window->counter;
 313         else
 314                 window->success_ratio = IWL_INVALID_VALUE;
 315
 316         fail_count = window->counter - window->success_counter;
 317
 318         /* Calculate average throughput, if we have enough history. */
 319         if ((fail_count >= IWL_RATE_MIN_FAILURE_TH) ||
 320             (window->success_counter >= IWL_RATE_MIN_SUCCESS_TH))
 321                 window->average_tpt = ((window->success_ratio *
 322                                 rs_sta->expected_tpt[index] + 64) / 128);
 323         else
 324                 window->average_tpt = IWL_INVALID_VALUE;
 325
 326         /* Tag this window as having been updated */
 327         window->stamp = jiffies;
 328
 329         spin_unlock_irqrestore(&rs_sta->lock, flags);
 330
 331 }
 332
 333 /*
 334  * Called after adding a new station to initialize rate scaling
 335  */
 336 void iwl3945_rs_rate_init(struct iwl_priv *priv, struct ieee80211_sta *sta, u8 sta_id)
 337 {
 338         struct ieee80211_hw *hw = priv->hw;
 339         struct ieee80211_conf *conf = &priv->hw->conf;
 340         struct iwl3945_sta_priv *psta;
 341         struct iwl3945_rs_sta *rs_sta;
 342         struct ieee80211_supported_band *sband;
 343         int i;
 344
 345         IWL_DEBUG_INFO(priv, "enter\n");
 346         if (sta_id == priv->contexts[IWL_RXON_CTX_BSS].bcast_sta_id)
 347                 goto out;
 348
 349         psta = (struct iwl3945_sta_priv *) sta->drv_priv;
 350         rs_sta = &psta->rs_sta;
 351         sband = hw->wiphy->bands[conf->channel->band];
 352
 353         rs_sta->priv = priv;
 354
 355         rs_sta->start_rate = IWL_RATE_INVALID;
 356
 357         /* default to just 802.11b */
 358         rs_sta->expected_tpt = iwl3945_expected_tpt_b;
 359
 360         rs_sta->last_partial_flush = jiffies;
 361         rs_sta->last_flush = jiffies;
 362         rs_sta->flush_time = IWL_RATE_FLUSH;
 363         rs_sta->last_tx_packets = 0;
 364
 365         rs_sta->rate_scale_flush.data = (unsigned long)rs_sta;
 366         rs_sta->rate_scale_flush.function = iwl3945_bg_rate_scale_flush;
 367
 368         for (i = 0; i < IWL_RATE_COUNT_3945; i++)
 369                 iwl3945_clear_window(&rs_sta->win[i]);
 370
 371         /* TODO: what is a good starting rate for STA? About middle? Maybe not
 372          * the lowest or the highest rate.. Could consider using RSSI from
 373          * previous packets? Need to have IEEE 802.1X auth succeed immediately
 374          * after assoc.. */
 375
 376         for (i = sband->n_bitrates - 1; i >= 0; i--) {
 377                 if (sta->supp_rates[sband->band] & (1 << i)) {
 378                         rs_sta->last_txrate_idx = i;
 379                         break;
 380                 }
 381         }
 382
 383         priv->_3945.sta_supp_rates = sta->supp_rates[sband->band];
 384         /* For 5 GHz band it start at IWL_FIRST_OFDM_RATE */
 385         if (sband->band == IEEE80211_BAND_5GHZ) {
 386                 rs_sta->last_txrate_idx += IWL_FIRST_OFDM_RATE;
 387                 priv->_3945.sta_supp_rates = priv->_3945.sta_supp_rates <<
 388                                                 IWL_FIRST_OFDM_RATE;
 389         }
 390
 391 out:
 392         priv->stations[sta_id].used &= ~IWL_STA_UCODE_INPROGRESS;
 393
 394         IWL_DEBUG_INFO(priv, "leave\n");
 395 }
 396
 397 static void *iwl3945_rs_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
 398 {
 399         return hw->priv;
 400 }
 401
 402 /* rate scale requires free function to be implemented */
 403 static void iwl3945_rs_free(void *priv)
 404 {
 405         return;
 406 }
 407
 408 static void *iwl3945_rs_alloc_sta(void *iwl_priv, struct ieee80211_sta *sta, gfp_t gfp)
 409 {
 410         struct iwl3945_rs_sta *rs_sta;
 411         struct iwl3945_sta_priv *psta = (void *) sta->drv_priv;
 412         struct iwl_priv *priv __maybe_unused = iwl_priv;
 413
 414         IWL_DEBUG_RATE(priv, "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         IWL_DEBUG_RATE(priv, "leave\n");
 422
 423         return rs_sta;
 424 }
 425
 426 static void iwl3945_rs_free_sta(void *iwl_priv, struct ieee80211_sta *sta,
 427                         void *priv_sta)
 428 {
 429         struct iwl3945_rs_sta *rs_sta = priv_sta;
 430
 431         /*
 432          * Be careful not to use any members of iwl3945_rs_sta (like trying
 433          * to use iwl_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 /**
 441  * iwl3945_rs_tx_status - Update rate control values based on Tx results
 442  *
 443  * NOTE: Uses iwl_priv->retry_rate for the # of retries attempted by
 444  * the hardware for each rate.
 445  */
 446 static void iwl3945_rs_tx_status(void *priv_rate, struct ieee80211_supported_band *sband,
 447                          struct ieee80211_sta *sta, void *priv_sta,
 448                          struct sk_buff *skb)
 449 {
 450         s8 retries = 0, current_count;
 451         int scale_rate_index, first_index, last_index;
 452         unsigned long flags;
 453         struct iwl_priv *priv = (struct iwl_priv *)priv_rate;
 454         struct iwl3945_rs_sta *rs_sta = priv_sta;
 455         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 456
 457         IWL_DEBUG_RATE(priv, "enter\n");
 458
 459         retries = info->status.rates[0].count;
 460         /* Sanity Check for retries */
 461         if (retries > IWL_RATE_RETRY_TH)
 462                 retries = IWL_RATE_RETRY_TH;
 463
 464         first_index = sband->bitrates[info->status.rates[0].idx].hw_value;
 465         if ((first_index < 0) || (first_index >= IWL_RATE_COUNT_3945)) {
 466                 IWL_DEBUG_RATE(priv, "leave: Rate out of bounds: %d\n", first_index);
 467                 return;
 468         }
 469
 470         if (!priv_sta) {
 471                 IWL_DEBUG_RATE(priv, "leave: No STA priv data to update!\n");
 472                 return;
 473         }
 474
 475         /* Treat uninitialized rate scaling data same as non-existing. */
 476         if (!rs_sta->priv) {
 477                 IWL_DEBUG_RATE(priv, "leave: STA priv data uninitialized!\n");
 478                 return;
 479         }
 480
 481
 482         rs_sta->tx_packets++;
 483
 484         scale_rate_index = first_index;
 485         last_index = first_index;
 486
 487         /*
 488          * Update the window for each rate.  We determine which rates
 489          * were Tx'd based on the total number of retries vs. the number
 490          * of retries configured for each rate -- currently set to the
 491          * priv value 'retry_rate' vs. rate specific
 492          *
 493          * On exit from this while loop last_index indicates the rate
 494          * at which the frame was finally transmitted (or failed if no
 495          * ACK)
 496          */
 497         while (retries > 1) {
 498                 if ((retries - 1) < priv->retry_rate) {
 499                         current_count = (retries - 1);
 500                         last_index = scale_rate_index;
 501                 } else {
 502                         current_count = priv->retry_rate;
 503                         last_index = iwl3945_rs_next_rate(priv,
 504                                                          scale_rate_index);
 505                 }
 506
 507                 /* Update this rate accounting for as many retries
 508                  * as was used for it (per current_count) */
 509                 iwl3945_collect_tx_data(rs_sta,
 510                                     &rs_sta->win[scale_rate_index],
 511                                     0, current_count, scale_rate_index);
 512                 IWL_DEBUG_RATE(priv, "Update rate %d for %d retries.\n",
 513                                scale_rate_index, current_count);
 514
 515                 retries -= current_count;
 516
 517                 scale_rate_index = last_index;
 518         }
 519
 520
 521         /* Update the last index window with success/failure based on ACK */
 522         IWL_DEBUG_RATE(priv, "Update rate %d with %s.\n",
 523                        last_index,
 524                        (info->flags & IEEE80211_TX_STAT_ACK) ?
 525                        "success" : "failure");
 526         iwl3945_collect_tx_data(rs_sta,
 527                             &rs_sta->win[last_index],
 528                             info->flags & IEEE80211_TX_STAT_ACK, 1, last_index);
 529
 530         /* We updated the rate scale window -- if its been more than
 531          * flush_time since the last run, schedule the flush
 532          * again */
 533         spin_lock_irqsave(&rs_sta->lock, flags);
 534
 535         if (!rs_sta->flush_pending &&
 536             time_after(jiffies, rs_sta->last_flush +
 537                        rs_sta->flush_time)) {
 538
 539                 rs_sta->last_partial_flush = jiffies;
 540                 rs_sta->flush_pending = 1;
 541                 mod_timer(&rs_sta->rate_scale_flush,
 542                           jiffies + rs_sta->flush_time);
 543         }
 544
 545         spin_unlock_irqrestore(&rs_sta->lock, flags);
 546
 547         IWL_DEBUG_RATE(priv, "leave\n");
 548 }
 549
 550 static u16 iwl3945_get_adjacent_rate(struct iwl3945_rs_sta *rs_sta,
 551                                  u8 index, u16 rate_mask, enum ieee80211_band band)
 552 {
 553         u8 high = IWL_RATE_INVALID;
 554         u8 low = IWL_RATE_INVALID;
 555         struct iwl_priv *priv __maybe_unused = rs_sta->priv;
 556
 557         /* 802.11A walks to the next literal adjacent rate in
 558          * the rate table */
 559         if (unlikely(band == IEEE80211_BAND_5GHZ)) {
 560                 int i;
 561                 u32 mask;
 562
 563                 /* Find the previous rate that is in the rate mask */
 564                 i = index - 1;
 565                 for (mask = (1 << i); i >= 0; i--, mask >>= 1) {
 566                         if (rate_mask & mask) {
 567                                 low = i;
 568                                 break;
 569                         }
 570                 }
 571
 572                 /* Find the next rate that is in the rate mask */
 573                 i = index + 1;
 574                 for (mask = (1 << i); i < IWL_RATE_COUNT_3945;
 575                      i++, mask <<= 1) {
 576                         if (rate_mask & mask) {
 577                                 high = i;
 578                                 break;
 579                         }
 580                 }
 581
 582                 return (high << 8) | low;
 583         }
 584
 585         low = index;
 586         while (low != IWL_RATE_INVALID) {
 587                 if (rs_sta->tgg)
 588                         low = iwl3945_rates[low].prev_rs_tgg;
 589                 else
 590                         low = iwl3945_rates[low].prev_rs;
 591                 if (low == IWL_RATE_INVALID)
 592                         break;
 593                 if (rate_mask & (1 << low))
 594                         break;
 595                 IWL_DEBUG_RATE(priv, "Skipping masked lower rate: %d\n", low);
 596         }
 597
 598         high = index;
 599         while (high != IWL_RATE_INVALID) {
 600                 if (rs_sta->tgg)
 601                         high = iwl3945_rates[high].next_rs_tgg;
 602                 else
 603                         high = iwl3945_rates[high].next_rs;
 604                 if (high == IWL_RATE_INVALID)
 605                         break;
 606                 if (rate_mask & (1 << high))
 607                         break;
 608                 IWL_DEBUG_RATE(priv, "Skipping masked higher rate: %d\n", high);
 609         }
 610
 611         return (high << 8) | low;
 612 }
 613
 614 /**
 615  * iwl3945_rs_get_rate - find the rate for the requested packet
 616  *
 617  * Returns the ieee80211_rate structure allocated by the driver.
 618  *
 619  * The rate control algorithm has no internal mapping between hw_mode's
 620  * rate ordering and the rate ordering used by the rate control algorithm.
 621  *
 622  * The rate control algorithm uses a single table of rates that goes across
 623  * the entire A/B/G spectrum vs. being limited to just one particular
 624  * hw_mode.
 625  *
 626  * As such, we can't convert the index obtained below into the hw_mode's
 627  * rate table and must reference the driver allocated rate table
 628  *
 629  */
 630 static void iwl3945_rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
 631                         void *priv_sta, struct ieee80211_tx_rate_control *txrc)
 632 {
 633         struct ieee80211_supported_band *sband = txrc->sband;
 634         struct sk_buff *skb = txrc->skb;
 635         u8 low = IWL_RATE_INVALID;
 636         u8 high = IWL_RATE_INVALID;
 637         u16 high_low;
 638         int index;
 639         struct iwl3945_rs_sta *rs_sta = priv_sta;
 640         struct iwl3945_rate_scale_data *window = NULL;
 641         int current_tpt = IWL_INVALID_VALUE;
 642         int low_tpt = IWL_INVALID_VALUE;
 643         int high_tpt = IWL_INVALID_VALUE;
 644         u32 fail_count;
 645         s8 scale_action = 0;
 646         unsigned long flags;
 647         u16 rate_mask;
 648         s8 max_rate_idx = -1;
 649         struct iwl_priv *priv __maybe_unused = (struct iwl_priv *)priv_r;
 650         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 651
 652         IWL_DEBUG_RATE(priv, "enter\n");
 653
 654         /* Treat uninitialized rate scaling data same as non-existing. */
 655         if (rs_sta && !rs_sta->priv) {
 656                 IWL_DEBUG_RATE(priv, "Rate scaling information not initialized yet.\n");
 657                 priv_sta = NULL;
 658         }
 659
 660         if (rate_control_send_low(sta, priv_sta, txrc))
 661                 return;
 662
 663         rate_mask = sta->supp_rates[sband->band];
 664
 665         /* get user max rate if set */
 666         max_rate_idx = txrc->max_rate_idx;
 667         if ((sband->band == IEEE80211_BAND_5GHZ) && (max_rate_idx != -1))
 668                 max_rate_idx += IWL_FIRST_OFDM_RATE;
 669         if ((max_rate_idx < 0) || (max_rate_idx >= IWL_RATE_COUNT))
 670                 max_rate_idx = -1;
 671
 672         index = min(rs_sta->last_txrate_idx & 0xffff, IWL_RATE_COUNT_3945 - 1);
 673
 674         if (sband->band == IEEE80211_BAND_5GHZ)
 675                 rate_mask = rate_mask << IWL_FIRST_OFDM_RATE;
 676
 677         spin_lock_irqsave(&rs_sta->lock, flags);
 678
 679         /* for recent assoc, choose best rate regarding
 680          * to rssi value
 681          */
 682         if (rs_sta->start_rate != IWL_RATE_INVALID) {
 683                 if (rs_sta->start_rate < index &&
 684                    (rate_mask & (1 << rs_sta->start_rate)))
 685                         index = rs_sta->start_rate;
 686                 rs_sta->start_rate = IWL_RATE_INVALID;
 687         }
 688
 689         /* force user max rate if set by user */
 690         if ((max_rate_idx != -1) && (max_rate_idx < index)) {
 691                 if (rate_mask & (1 << max_rate_idx))
 692                         index = max_rate_idx;
 693         }
 694
 695         window = &(rs_sta->win[index]);
 696
 697         fail_count = window->counter - window->success_counter;
 698
 699         if (((fail_count < IWL_RATE_MIN_FAILURE_TH) &&
 700              (window->success_counter < IWL_RATE_MIN_SUCCESS_TH))) {
 701                 spin_unlock_irqrestore(&rs_sta->lock, flags);
 702
 703                 IWL_DEBUG_RATE(priv, "Invalid average_tpt on rate %d: "
 704                                "counter: %d, success_counter: %d, "
 705                                "expected_tpt is %sNULL\n",
 706                                index,
 707                                window->counter,
 708                                window->success_counter,
 709                                rs_sta->expected_tpt ? "not " : "");
 710
 711            /* Can't calculate this yet; not enough history */
 712                 window->average_tpt = IWL_INVALID_VALUE;
 713                 goto out;
 714
 715         }
 716
 717         current_tpt = window->average_tpt;
 718
 719         high_low = iwl3945_get_adjacent_rate(rs_sta, index, rate_mask,
 720                                              sband->band);
 721         low = high_low & 0xff;
 722         high = (high_low >> 8) & 0xff;
 723
 724         /* If user set max rate, dont allow higher than user constrain */
 725         if ((max_rate_idx != -1) && (max_rate_idx < high))
 726                 high = IWL_RATE_INVALID;
 727
 728         /* Collect Measured throughputs of adjacent rates */
 729         if (low != IWL_RATE_INVALID)
 730                 low_tpt = rs_sta->win[low].average_tpt;
 731
 732         if (high != IWL_RATE_INVALID)
 733                 high_tpt = rs_sta->win[high].average_tpt;
 734
 735         spin_unlock_irqrestore(&rs_sta->lock, flags);
 736
 737         scale_action = 0;
 738
 739         /* Low success ratio , need to drop the rate */
 740         if ((window->success_ratio < IWL_RATE_DECREASE_TH) || !current_tpt) {
 741                 IWL_DEBUG_RATE(priv, "decrease rate because of low success_ratio\n");
 742                 scale_action = -1;
 743         /* No throughput measured yet for adjacent rates,
 744          * try increase */
 745         } else if ((low_tpt == IWL_INVALID_VALUE) &&
 746                    (high_tpt == IWL_INVALID_VALUE)) {
 747
 748                 if (high != IWL_RATE_INVALID && window->success_ratio >= IWL_RATE_INCREASE_TH)
 749                         scale_action = 1;
 750                 else if (low != IWL_RATE_INVALID)
 751                         scale_action = 0;
 752
 753         /* Both adjacent throughputs are measured, but neither one has
 754          * better throughput; we're using the best rate, don't change
 755          * it! */
 756         } else if ((low_tpt != IWL_INVALID_VALUE) &&
 757                  (high_tpt != IWL_INVALID_VALUE) &&
 758                  (low_tpt < current_tpt) && (high_tpt < current_tpt)) {
 759
 760                 IWL_DEBUG_RATE(priv, "No action -- low [%d] & high [%d] < "
 761                                "current_tpt [%d]\n",
 762                                low_tpt, high_tpt, current_tpt);
 763                 scale_action = 0;
 764
 765         /* At least one of the rates has better throughput */
 766         } else {
 767                 if (high_tpt != IWL_INVALID_VALUE) {
 768
 769                         /* High rate has better throughput, Increase
 770                          * rate */
 771                         if (high_tpt > current_tpt &&
 772                                 window->success_ratio >= IWL_RATE_INCREASE_TH)
 773                                 scale_action = 1;
 774                         else {
 775                                 IWL_DEBUG_RATE(priv,
 776                                     "decrease rate because of high tpt\n");
 777                                 scale_action = 0;
 778                         }
 779                 } else if (low_tpt != IWL_INVALID_VALUE) {
 780                         if (low_tpt > current_tpt) {
 781                                 IWL_DEBUG_RATE(priv,
 782                                     "decrease rate because of low tpt\n");
 783                                 scale_action = -1;
 784                         } else if (window->success_ratio >= IWL_RATE_INCREASE_TH) {
 785                                 /* Lower rate has better
 786                                  * throughput,decrease rate */
 787                                 scale_action = 1;
 788                         }
 789                 }
 790         }
 791
 792         /* Sanity check; asked for decrease, but success rate or throughput
 793          * has been good at old rate.  Don't change it. */
 794         if ((scale_action == -1) && (low != IWL_RATE_INVALID) &&
 795                     ((window->success_ratio > IWL_RATE_HIGH_TH) ||
 796                      (current_tpt > (100 * rs_sta->expected_tpt[low]))))
 797                 scale_action = 0;
 798
 799         switch (scale_action) {
 800         case -1:
 801
 802                 /* Decrese rate */
 803                 if (low != IWL_RATE_INVALID)
 804                         index = low;
 805                 break;
 806
 807         case 1:
 808                 /* Increase rate */
 809                 if (high != IWL_RATE_INVALID)
 810                         index = high;
 811
 812                 break;
 813
 814         case 0:
 815         default:
 816                 /* No change */
 817                 break;
 818         }
 819
 820         IWL_DEBUG_RATE(priv, "Selected %d (action %d) - low %d high %d\n",
 821                        index, scale_action, low, high);
 822
 823  out:
 824
 825         if (sband->band == IEEE80211_BAND_5GHZ) {
 826                 if (WARN_ON_ONCE(index < IWL_FIRST_OFDM_RATE))
 827                         index = IWL_FIRST_OFDM_RATE;
 828                 rs_sta->last_txrate_idx = index;
 829                 info->control.rates[0].idx = index - IWL_FIRST_OFDM_RATE;
 830         } else {
 831                 rs_sta->last_txrate_idx = index;
 832                 info->control.rates[0].idx = rs_sta->last_txrate_idx;
 833         }
 834
 835         IWL_DEBUG_RATE(priv, "leave: %d\n", index);
 836 }
 837
 838 #ifdef CONFIG_MAC80211_DEBUGFS
 839 static int iwl3945_open_file_generic(struct inode *inode, struct file *file)
 840 {
 841         file->private_data = inode->i_private;
 842         return 0;
 843 }
 844
 845 static ssize_t iwl3945_sta_dbgfs_stats_table_read(struct file *file,
 846                                                   char __user *user_buf,
 847                                                   size_t count, loff_t *ppos)
 848 {
 849         char *buff;
 850         int desc = 0;
 851         int j;
 852         ssize_t ret;
 853         struct iwl3945_rs_sta *lq_sta = file->private_data;
 854
 855         buff = kmalloc(1024, GFP_KERNEL);
 856         if (!buff)
 857                 return -ENOMEM;
 858
 859         desc += sprintf(buff + desc, "tx packets=%d last rate index=%d\n"
 860                         "rate=0x%X flush time %d\n",
 861                         lq_sta->tx_packets,
 862                         lq_sta->last_txrate_idx,
 863                         lq_sta->start_rate, jiffies_to_msecs(lq_sta->flush_time));
 864         for (j = 0; j < IWL_RATE_COUNT_3945; j++) {
 865                 desc += sprintf(buff+desc,
 866                                 "counter=%d success=%d %%=%d\n",
 867                                 lq_sta->win[j].counter,
 868                                 lq_sta->win[j].success_counter,
 869                                 lq_sta->win[j].success_ratio);
 870         }
 871         ret = simple_read_from_buffer(user_buf, count, ppos, buff, desc);
 872         kfree(buff);
 873         return ret;
 874 }
 875
 876 static const struct file_operations rs_sta_dbgfs_stats_table_ops = {
 877         .read = iwl3945_sta_dbgfs_stats_table_read,
 878         .open = iwl3945_open_file_generic,
 879         .llseek = default_llseek,
 880 };
 881
 882 static void iwl3945_add_debugfs(void *priv, void *priv_sta,
 883                                 struct dentry *dir)
 884 {
 885         struct iwl3945_rs_sta *lq_sta = priv_sta;
 886
 887         lq_sta->rs_sta_dbgfs_stats_table_file =
 888                 debugfs_create_file("rate_stats_table", 0600, dir,
 889                 lq_sta, &rs_sta_dbgfs_stats_table_ops);
 890
 891 }
 892
 893 static void iwl3945_remove_debugfs(void *priv, void *priv_sta)
 894 {
 895         struct iwl3945_rs_sta *lq_sta = priv_sta;
 896         debugfs_remove(lq_sta->rs_sta_dbgfs_stats_table_file);
 897 }
 898 #endif
 899
 900 /*
 901  * Initialization of rate scaling information is done by driver after
 902  * the station is added. Since mac80211 calls this function before a
 903  * station is added we ignore it.
 904  */
 905 static void iwl3945_rs_rate_init_stub(void *priv_r,
 906                                 struct ieee80211_supported_band *sband,
 907                               struct ieee80211_sta *sta, void *priv_sta)
 908 {
 909 }
 910
 911 static struct rate_control_ops rs_ops = {
 912         .module = NULL,
 913         .name = RS_NAME,
 914         .tx_status = iwl3945_rs_tx_status,
 915         .get_rate = iwl3945_rs_get_rate,
 916         .rate_init = iwl3945_rs_rate_init_stub,
 917         .alloc = iwl3945_rs_alloc,
 918         .free = iwl3945_rs_free,
 919         .alloc_sta = iwl3945_rs_alloc_sta,
 920         .free_sta = iwl3945_rs_free_sta,
 921 #ifdef CONFIG_MAC80211_DEBUGFS
 922         .add_sta_debugfs = iwl3945_add_debugfs,
 923         .remove_sta_debugfs = iwl3945_remove_debugfs,
 924 #endif
 925
 926 };
 927 void iwl3945_rate_scale_init(struct ieee80211_hw *hw, s32 sta_id)
 928 {
 929         struct iwl_priv *priv = hw->priv;
 930         s32 rssi = 0;
 931         unsigned long flags;
 932         struct iwl3945_rs_sta *rs_sta;
 933         struct ieee80211_sta *sta;
 934         struct iwl3945_sta_priv *psta;
 935
 936         IWL_DEBUG_RATE(priv, "enter\n");
 937
 938         rcu_read_lock();
 939
 940         sta = ieee80211_find_sta(priv->contexts[IWL_RXON_CTX_BSS].vif,
 941                                  priv->stations[sta_id].sta.sta.addr);
 942         if (!sta) {
 943                 IWL_DEBUG_RATE(priv, "Unable to find station to initialize rate scaling.\n");
 944                 rcu_read_unlock();
 945                 return;
 946         }
 947
 948         psta = (void *) sta->drv_priv;
 949         rs_sta = &psta->rs_sta;
 950
 951         spin_lock_irqsave(&rs_sta->lock, flags);
 952
 953         rs_sta->tgg = 0;
 954         switch (priv->band) {
 955         case IEEE80211_BAND_2GHZ:
 956                 /* TODO: this always does G, not a regression */
 957                 if (priv->contexts[IWL_RXON_CTX_BSS].active.flags &
 958                                                 RXON_FLG_TGG_PROTECT_MSK) {
 959                         rs_sta->tgg = 1;
 960                         rs_sta->expected_tpt = iwl3945_expected_tpt_g_prot;
 961                 } else
 962                         rs_sta->expected_tpt = iwl3945_expected_tpt_g;
 963                 break;
 964
 965         case IEEE80211_BAND_5GHZ:
 966                 rs_sta->expected_tpt = iwl3945_expected_tpt_a;
 967                 break;
 968         case IEEE80211_NUM_BANDS:
 969                 BUG();
 970                 break;
 971         }
 972
 973         spin_unlock_irqrestore(&rs_sta->lock, flags);
 974
 975         rssi = priv->_3945.last_rx_rssi;
 976         if (rssi == 0)
 977                 rssi = IWL_MIN_RSSI_VAL;
 978
 979         IWL_DEBUG_RATE(priv, "Network RSSI: %d\n", rssi);
 980
 981         rs_sta->start_rate = iwl3945_get_rate_index_by_rssi(rssi, priv->band);
 982
 983         IWL_DEBUG_RATE(priv, "leave: rssi %d assign rate index: "
 984                        "%d (plcp 0x%x)\n", rssi, rs_sta->start_rate,
 985                        iwl3945_rates[rs_sta->start_rate].plcp);
 986         rcu_read_unlock();
 987 }
 988
 989 int iwl3945_rate_control_register(void)
 990 {
 991         return ieee80211_rate_control_register(&rs_ops);
 992 }
 993
 994 void iwl3945_rate_control_unregister(void)
 995 {
 996         ieee80211_rate_control_unregister(&rs_ops);
 997 }