package/mac80211/patches/560-minstrel_ht.patch

   1 --- a/net/mac80211/Makefile
   2 +++ b/net/mac80211/Makefile
   3 @@ -47,8 +47,8 @@ CFLAGS_driver-trace.o := -I$(src)
   4  rc80211_pid-y := rc80211_pid_algo.o
   5  rc80211_pid-$(CONFIG_MAC80211_DEBUGFS) += rc80211_pid_debugfs.o
   6
   7 -rc80211_minstrel-y := rc80211_minstrel.o
   8 -rc80211_minstrel-$(CONFIG_MAC80211_DEBUGFS) += rc80211_minstrel_debugfs.o
   9 +rc80211_minstrel-y := rc80211_minstrel.o rc80211_minstrel_ht.o
  10 +rc80211_minstrel-$(CONFIG_MAC80211_DEBUGFS) += rc80211_minstrel_debugfs.o rc80211_minstrel_ht_debugfs.o
  11
  12  mac80211-$(CONFIG_MAC80211_RC_PID) += $(rc80211_pid-y)
  13  mac80211-$(CONFIG_MAC80211_RC_MINSTREL) += $(rc80211_minstrel-y)
  14 --- a/net/mac80211/main.c
  15 +++ b/net/mac80211/main.c
  16 @@ -714,6 +714,10 @@ static int __init ieee80211_init(void)
  17         if (ret)
  18                 return ret;
  19
  20 +       ret = rc80211_minstrel_ht_init();
  21 +       if (ret)
  22 +               goto err_minstrel;
  23 +
  24         ret = rc80211_pid_init();
  25         if (ret)
  26                 goto err_pid;
  27 @@ -726,6 +730,8 @@ static int __init ieee80211_init(void)
  28   err_netdev:
  29         rc80211_pid_exit();
  30   err_pid:
  31 +       rc80211_minstrel_ht_exit();
  32 + err_minstrel:
  33         rc80211_minstrel_exit();
  34
  35         return ret;
  36 @@ -734,6 +740,7 @@ static int __init ieee80211_init(void)
  37  static void __exit ieee80211_exit(void)
  38  {
  39         rc80211_pid_exit();
  40 +       rc80211_minstrel_ht_exit();
  41         rc80211_minstrel_exit();
  42
  43         /*
  44 --- a/net/mac80211/rate.h
  45 +++ b/net/mac80211/rate.h
  46 @@ -137,6 +137,8 @@ static inline void rc80211_pid_exit(void
  47  #ifdef CONFIG_MAC80211_RC_MINSTREL
  48  extern int rc80211_minstrel_init(void);
  49  extern void rc80211_minstrel_exit(void);
  50 +extern int rc80211_minstrel_ht_init(void);
  51 +extern void rc80211_minstrel_ht_exit(void);
  52  #else
  53  static inline int rc80211_minstrel_init(void)
  54  {
  55 @@ -145,6 +147,13 @@ static inline int rc80211_minstrel_init(
  56  static inline void rc80211_minstrel_exit(void)
  57  {
  58  }
  59 +static inline int rc80211_minstrel_ht_init(void)
  60 +{
  61 +       return 0;
  62 +}
  63 +static inline void rc80211_minstrel_ht_exit(void)
  64 +{
  65 +}
  66  #endif
  67
  68
  69 --- /dev/null
  70 +++ b/net/mac80211/rc80211_minstrel_ht.c
  71 @@ -0,0 +1,824 @@
  72 +/*
  73 + * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
  74 + *
  75 + * This program is free software; you can redistribute it and/or modify
  76 + * it under the terms of the GNU General Public License version 2 as
  77 + * published by the Free Software Foundation.
  78 + */
  79 +#include <linux/netdevice.h>
  80 +#include <linux/types.h>
  81 +#include <linux/skbuff.h>
  82 +#include <linux/debugfs.h>
  83 +#include <linux/random.h>
  84 +#include <linux/ieee80211.h>
  85 +#include <net/mac80211.h>
  86 +#include "rate.h"
  87 +#include "rc80211_minstrel.h"
  88 +#include "rc80211_minstrel_ht.h"
  89 +
  90 +#define AVG_PKT_SIZE   1200
  91 +#define SAMPLE_COLUMNS 10
  92 +#define EWMA_LEVEL             75
  93 +
  94 +/* Number of bits for an average sized packet */
  95 +#define MCS_NBITS (AVG_PKT_SIZE << 3)
  96 +
  97 +/* Number of symbols for a packet with (bps) bits per symbol */
  98 +#define MCS_NSYMS(bps) ((MCS_NBITS + (bps) - 1) / (bps))
  99 +
 100 +/* Transmission time for a packet containing (syms) symbols */
 101 +#define MCS_SYMBOL_TIME(sgi, syms)                                     \
 102 +       (sgi ?                                                          \
 103 +         ((syms) * 18 + 4) / 5 :       /* syms * 3.6 us */             \
 104 +         (syms) << 2                   /* syms * 4 us */               \
 105 +       )
 106 +
 107 +/* Transmit duration for the raw data part of an average sized packet */
 108 +#define MCS_DURATION(streams, sgi, bps) MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps)))
 109 +
 110 +/* MCS rate information for an MCS group */
 111 +#define MCS_GROUP(_streams, _sgi, _ht40) {                             \
 112 +       .streams = _streams,                                            \
 113 +       .flags =                                                        \
 114 +               (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |                 \
 115 +               (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),             \
 116 +       .duration = {                                                   \
 117 +               MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26),          \
 118 +               MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52),         \
 119 +               MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78),         \
 120 +               MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104),        \
 121 +               MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156),        \
 122 +               MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208),        \
 123 +               MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234),        \
 124 +               MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260)         \
 125 +       }                                                               \
 126 +}
 127 +
 128 +#define MINSTREL_INTFL_SAMPLE_SLOT0    BIT(30)
 129 +#define MINSTREL_INTFL_SAMPLE_SLOT1    BIT(31)
 130 +
 131 +/*
 132 + * To enable sufficiently targeted rate sampling, MCS rates are divided into
 133 + * groups, based on the number of streams and flags (HT40, SGI) that they
 134 + * use.
 135 + */
 136 +const struct mcs_group minstrel_mcs_groups[] = {
 137 +       MCS_GROUP(1, 0, 0),
 138 +       MCS_GROUP(2, 0, 0),
 139 +#if MINSTREL_MAX_STREAMS >= 3
 140 +       MCS_GROUP(3, 0, 0),
 141 +#endif
 142 +
 143 +       MCS_GROUP(1, 1, 0),
 144 +       MCS_GROUP(2, 1, 0),
 145 +#if MINSTREL_MAX_STREAMS >= 3
 146 +       MCS_GROUP(3, 1, 0),
 147 +#endif
 148 +
 149 +       MCS_GROUP(1, 0, 1),
 150 +       MCS_GROUP(2, 0, 1),
 151 +#if MINSTREL_MAX_STREAMS >= 3
 152 +       MCS_GROUP(3, 0, 1),
 153 +#endif
 154 +
 155 +       MCS_GROUP(1, 1, 1),
 156 +       MCS_GROUP(2, 1, 1),
 157 +#if MINSTREL_MAX_STREAMS >= 3
 158 +       MCS_GROUP(3, 1, 1),
 159 +#endif
 160 +};
 161 +
 162 +static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES];
 163 +
 164 +/*
 165 + * Perform EWMA (Exponentially Weighted Moving Average) calculation
 166 + */
 167 +static int
 168 +minstrel_ewma(int old, int new, int weight)
 169 +{
 170 +       return (new * (100 - weight) + old * weight) / 100;
 171 +}
 172 +
 173 +/*
 174 + * Look up an MCS group index based on mac80211 rate information
 175 + */
 176 +static int
 177 +minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
 178 +{
 179 +       int streams = (rate->idx / MCS_GROUP_RATES) + 1;
 180 +       u32 flags = IEEE80211_TX_RC_SHORT_GI | IEEE80211_TX_RC_40_MHZ_WIDTH;
 181 +       int i;
 182 +
 183 +       for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) {
 184 +               if (minstrel_mcs_groups[i].streams != streams)
 185 +                       continue;
 186 +               if (minstrel_mcs_groups[i].flags != (rate->flags & flags))
 187 +                       continue;
 188 +
 189 +               return i;
 190 +       }
 191 +
 192 +       WARN_ON(1);
 193 +       return 0;
 194 +}
 195 +
 196 +static inline struct minstrel_rate_stats *
 197 +minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
 198 +{
 199 +       return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
 200 +}
 201 +
 202 +
 203 +/*
 204 + * Recalculate success probabilities and counters for a rate using EWMA
 205 + */
 206 +static void
 207 +minstrel_calc_rate_ewma(struct minstrel_priv *mp, struct minstrel_rate_stats *mr)
 208 +{
 209 +       if (mr->attempts) {
 210 +               mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
 211 +               if (!mr->att_hist)
 212 +                       mr->probability = mr->cur_prob;
 213 +               else
 214 +                       mr->probability = minstrel_ewma(mr->probability,
 215 +                               mr->cur_prob, EWMA_LEVEL);
 216 +               mr->att_hist += mr->attempts;
 217 +               mr->succ_hist += mr->success;
 218 +       }
 219 +       mr->last_success = mr->success;
 220 +       mr->last_attempts = mr->attempts;
 221 +       mr->success = 0;
 222 +       mr->attempts = 0;
 223 +}
 224 +
 225 +/*
 226 + * Calculate throughput based on the average A-MPDU length, taking into account
 227 + * the expected number of retransmissions and their expected length
 228 + */
 229 +static void
 230 +minstrel_ht_calc_tp(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
 231 +                    int group, int rate)
 232 +{
 233 +       struct minstrel_rate_stats *mr;
 234 +       unsigned int usecs;
 235 +
 236 +       mr = &mi->groups[group].rates[rate];
 237 +
 238 +       if (mr->probability < MINSTREL_FRAC(1, 10)) {
 239 +               mr->cur_tp = 0;
 240 +               return;
 241 +       }
 242 +
 243 +       usecs = mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
 244 +       usecs += minstrel_mcs_groups[group].duration[rate];
 245 +       mr->cur_tp = MINSTREL_TRUNC((1000000 / usecs) * mr->probability);
 246 +}
 247 +
 248 +/*
 249 + * Update rate statistics and select new primary rates
 250 + *
 251 + * Rules for rate selection:
 252 + *  - max_prob_rate must use only one stream, as a tradeoff between delivery
 253 + *    probability and throughput during strong fluctuations
 254 + *  - as long as the max prob rate has a probability of more than 3/4, pick
 255 + *    higher throughput rates, even if the probablity is a bit lower
 256 + */
 257 +static void
 258 +minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 259 +{
 260 +       struct minstrel_mcs_group_data *mg;
 261 +       struct minstrel_rate_stats *mr;
 262 +       int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
 263 +       int group, i, index;
 264 +
 265 +       mi->max_tp_rate = 0;
 266 +       mi->max_tp_rate2 = 0;
 267 +       mi->max_prob_rate = 0;
 268 +
 269 +       for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
 270 +               cur_prob = 0;
 271 +               cur_prob_tp = 0;
 272 +               cur_tp = 0;
 273 +               cur_tp2 = 0;
 274 +
 275 +               mg = &mi->groups[group];
 276 +               if (!mg->supported)
 277 +                       continue;
 278 +
 279 +               mg->max_tp_rate = 0;
 280 +               mg->max_tp_rate2 = 0;
 281 +               mg->max_prob_rate = 0;
 282 +
 283 +               for (i = 0; i < MCS_GROUP_RATES; i++) {
 284 +                       if (!(mg->supported & BIT(i)))
 285 +                               continue;
 286 +
 287 +                       mr = &mg->rates[i];
 288 +                       mr->retry_updated = false;
 289 +                       index = MCS_GROUP_RATES * group + i;
 290 +                       minstrel_calc_rate_ewma(mp, mr);
 291 +                       minstrel_ht_calc_tp(mp, mi, group, i);
 292 +
 293 +                       if (!mr->cur_tp)
 294 +                               continue;
 295 +
 296 +                       /* ignore the lowest rate of each single-stream group */
 297 +                       if (!i && minstrel_mcs_groups[group].streams == 1)
 298 +                               continue;
 299 +
 300 +                       if ((mr->cur_tp > cur_prob_tp && mr->probability >
 301 +                            MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
 302 +                               mg->max_prob_rate = index;
 303 +                               cur_prob = mr->probability;
 304 +                       }
 305 +
 306 +                       if (mr->cur_tp > cur_tp) {
 307 +                               swap(index, mg->max_tp_rate);
 308 +                               cur_tp = mr->cur_tp;
 309 +                               mr = minstrel_get_ratestats(mi, index);
 310 +                       }
 311 +
 312 +                       if (index == mg->max_tp_rate)
 313 +                               continue;
 314 +
 315 +                       if (mr->cur_tp > cur_tp2) {
 316 +                               mg->max_tp_rate2 = index;
 317 +                               cur_tp2 = mr->cur_tp;
 318 +                       }
 319 +               }
 320 +       }
 321 +
 322 +       cur_prob = 0;
 323 +       cur_prob_tp = 0;
 324 +       cur_tp = 0;
 325 +       cur_tp2 = 0;
 326 +       for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
 327 +               mg = &mi->groups[group];
 328 +               if (!mg->supported)
 329 +                       continue;
 330 +
 331 +               mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
 332 +               if (cur_prob_tp < mr->cur_tp &&
 333 +                   minstrel_mcs_groups[group].streams == 1) {
 334 +                       mi->max_prob_rate = mg->max_prob_rate;
 335 +                       cur_prob = mr->cur_prob;
 336 +               }
 337 +
 338 +               mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
 339 +               if (cur_tp < mr->cur_tp) {
 340 +                       mi->max_tp_rate = mg->max_tp_rate;
 341 +                       cur_tp = mr->cur_tp;
 342 +               }
 343 +
 344 +               mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
 345 +               if (cur_tp2 < mr->cur_tp) {
 346 +                       mi->max_tp_rate2 = mg->max_tp_rate2;
 347 +                       cur_tp2 = mr->cur_tp;
 348 +               }
 349 +       }
 350 +
 351 +       mi->stats_update = jiffies;
 352 +}
 353 +
 354 +static bool
 355 +minstrel_ht_txstat_valid(struct ieee80211_tx_rate *rate)
 356 +{
 357 +       if (!rate->count)
 358 +               return false;
 359 +
 360 +       if (rate->idx < 0)
 361 +               return false;
 362 +
 363 +       return !!(rate->flags & IEEE80211_TX_RC_MCS);
 364 +}
 365 +
 366 +static void
 367 +minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
 368 +{
 369 +       struct minstrel_mcs_group_data *mg;
 370 +
 371 +       for (;;) {
 372 +               mi->sample_group++;
 373 +               mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
 374 +               mg = &mi->groups[mi->sample_group];
 375 +
 376 +               if (!mg->supported)
 377 +                       continue;
 378 +
 379 +               if (++mg->index > MCS_GROUP_RATES) {
 380 +                       mg->index = 0;
 381 +                       if (++mg->column > ARRAY_SIZE(sample_table))
 382 +                               mg->column = 0;
 383 +               }
 384 +               break;
 385 +       }
 386 +}
 387 +
 388 +static void
 389 +minstrel_downgrade_rate(struct minstrel_ht_sta *mi, int *idx, int type)
 390 +{
 391 +       int group, orig_group;
 392 +
 393 +       orig_group = group = *idx / MCS_GROUP_RATES;
 394 +       while (group > 0) {
 395 +               group--;
 396 +
 397 +               if (!mi->groups[group].supported)
 398 +                       continue;
 399 +
 400 +               if (minstrel_mcs_groups[group].streams >=
 401 +                   minstrel_mcs_groups[orig_group].streams)
 402 +                       continue;
 403 +
 404 +               switch(type) {
 405 +               case 0:
 406 +                       *idx = mi->groups[group].max_tp_rate;
 407 +                       break;
 408 +               case 1:
 409 +                       *idx = mi->groups[group].max_tp_rate2;
 410 +                       break;
 411 +               }
 412 +               break;
 413 +       }
 414 +}
 415 +
 416 +
 417 +static void
 418 +minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
 419 +                      struct ieee80211_sta *sta, void *priv_sta,
 420 +                      struct sk_buff *skb)
 421 +{
 422 +       struct minstrel_ht_sta_priv *msp = priv_sta;
 423 +       struct minstrel_ht_sta *mi = &msp->ht;
 424 +       struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 425 +       struct ieee80211_tx_rate *ar = info->status.rates;
 426 +       struct minstrel_rate_stats *rate, *rate2;
 427 +       struct minstrel_priv *mp = priv;
 428 +       bool last = false;
 429 +       int group;
 430 +       int i = 0;
 431 +
 432 +       if (!msp->is_ht)
 433 +               return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
 434 +
 435 +       /* This packet was aggregated but doesn't carry status info */
 436 +       if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
 437 +           !(info->flags & IEEE80211_TX_STAT_AMPDU))
 438 +               return;
 439 +
 440 +       if (!info->status.ampdu_len) {
 441 +               info->status.ampdu_ack_len = 1;
 442 +               info->status.ampdu_len = 1;
 443 +       }
 444 +
 445 +       mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
 446 +               MINSTREL_FRAC(info->status.ampdu_len, 1), 90);
 447 +
 448 +       for (i = 0; !last; i++) {
 449 +               last = (i == IEEE80211_TX_MAX_RATES - 1) ||
 450 +                      !minstrel_ht_txstat_valid(&ar[i + 1]);
 451 +
 452 +               if (!minstrel_ht_txstat_valid(&ar[i]))
 453 +                       break;
 454 +
 455 +               if ((i == 0 && (info->flags & MINSTREL_INTFL_SAMPLE_SLOT0)) ||
 456 +                   (i == 1 && (info->flags & MINSTREL_INTFL_SAMPLE_SLOT1))) {
 457 +                       if (mi->sample_pending > 0)
 458 +                               mi->sample_pending--;
 459 +                       mi->sample_packets++;
 460 +                       minstrel_next_sample_idx(mi);
 461 +               }
 462 +
 463 +               group = minstrel_ht_get_group_idx(&ar[i]);
 464 +               rate = &mi->groups[group].rates[ar[i].idx % 8];
 465 +
 466 +               if (last && (info->flags & IEEE80211_TX_STAT_ACK))
 467 +                       rate->success += info->status.ampdu_ack_len;
 468 +
 469 +               rate->attempts += ar[i].count * info->status.ampdu_len;
 470 +       }
 471 +
 472 +
 473 +       /*
 474 +        * check for sudden death of spatial multiplexing,
 475 +        * downgrade to a lower number of streams if necessary.
 476 +        */
 477 +       rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
 478 +       if (MINSTREL_FRAC(rate->success, rate->attempts) <
 479 +           MINSTREL_FRAC(20, 100) && rate->attempts > 15)
 480 +               minstrel_downgrade_rate(mi, &mi->max_tp_rate, 0);
 481 +
 482 +       rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
 483 +       if (MINSTREL_FRAC(rate->success, rate->attempts) <
 484 +           MINSTREL_FRAC(20, 100) && rate->attempts > 15)
 485 +               minstrel_downgrade_rate(mi, &mi->max_tp_rate2, 1);
 486 +
 487 +       if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000))
 488 +               minstrel_ht_update_stats(mp, mi);
 489 +}
 490 +
 491 +static void
 492 +minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
 493 +                         int index)
 494 +{
 495 +       struct minstrel_rate_stats *mr;
 496 +       const struct mcs_group *group;
 497 +       unsigned int tx_time, tx_time_rtscts, tx_time_data;
 498 +       unsigned int cw = mp->cw_min;
 499 +       unsigned int t_slot = 9; /* FIXME */
 500 +       unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
 501 +
 502 +       mr = minstrel_get_ratestats(mi, index);
 503 +       if (mr->probability < MINSTREL_FRAC(1, 10)) {
 504 +               mr->retry_count = 1;
 505 +               mr->retry_count_rtscts = 1;
 506 +               return;
 507 +       }
 508 +
 509 +       mr->retry_count = 2;
 510 +       mr->retry_count_rtscts = 2;
 511 +       mr->retry_updated = true;
 512 +
 513 +       group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
 514 +       tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len;
 515 +       tx_time = 2 * (t_slot + mi->overhead + tx_time_data);
 516 +       tx_time_rtscts = 2 * (t_slot + mi->overhead_rtscts + tx_time_data);
 517 +       do {
 518 +               cw = (cw << 1) | 1;
 519 +               cw = min(cw, mp->cw_max);
 520 +               tx_time += cw + t_slot + mi->overhead;
 521 +               tx_time_rtscts += cw + t_slot + mi->overhead_rtscts;
 522 +               if (tx_time_rtscts < mp->segment_size)
 523 +                       mr->retry_count_rtscts++;
 524 +       } while ((tx_time < mp->segment_size) &&
 525 +                (++mr->retry_count < mp->max_retry));
 526 +}
 527 +
 528 +
 529 +static void
 530 +minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
 531 +                     struct ieee80211_tx_rate *rate, int index,
 532 +                     struct ieee80211_tx_rate_control *txrc,
 533 +                     bool sample, bool rtscts)
 534 +{
 535 +       const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
 536 +       struct minstrel_rate_stats *mr;
 537 +
 538 +       mr = minstrel_get_ratestats(mi, index);
 539 +       if (!mr->retry_updated)
 540 +               minstrel_calc_retransmit(mp, mi, index);
 541 +
 542 +       if (rtscts)
 543 +               rate->count = mr->retry_count_rtscts;
 544 +       else
 545 +               rate->count = mr->retry_count;
 546 +
 547 +       rate->flags = IEEE80211_TX_RC_MCS | group->flags;
 548 +       if (txrc->short_preamble)
 549 +               rate->flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
 550 +       if (txrc->rts || rtscts)
 551 +               rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS;
 552 +       rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES;
 553 +}
 554 +
 555 +static inline int
 556 +minstrel_get_duration(int index)
 557 +{
 558 +       const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
 559 +       return group->duration[index % MCS_GROUP_RATES];
 560 +}
 561 +
 562 +static int
 563 +minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
 564 +                         bool *defer)
 565 +{
 566 +       struct minstrel_rate_stats *mr;
 567 +       struct minstrel_mcs_group_data *mg;
 568 +       int sample_idx = 0;
 569 +       int sample_rate;
 570 +       int delta;
 571 +
 572 +       if (mp->has_mrr)
 573 +               sample_rate = mp->lookaround_rate_mrr;
 574 +       else
 575 +               sample_rate = mp->lookaround_rate;
 576 +
 577 +       delta = (mi->total_packets * sample_rate) / 100 - mi->sample_packets;
 578 +       delta -= mi->sample_pending / 2;
 579 +
 580 +       if (delta <= 0)
 581 +               return -1;
 582 +
 583 +       delta -= 16;
 584 +       if (delta > 1) {
 585 +               /* With multi-rate retry, not every planned sample
 586 +               * attempt actually gets used, due to the way the retry
 587 +               * chain is set up - [max_tp,sample,prob,lowest] for
 588 +               * sample_rate < max_tp.
 589 +               *
 590 +               * If there's too much sampling backlog and the link
 591 +               * starts getting worse, minstrel would start bursting
 592 +               * out lots of sampling frames, which would result
 593 +               * in a large throughput loss.
 594 +               */
 595 +               mi->sample_packets += delta - 1;
 596 +       }
 597 +
 598 +       mg = &mi->groups[mi->sample_group];
 599 +       sample_idx = sample_table[mg->column][mg->index];
 600 +       mr = &mg->rates[sample_idx];
 601 +       sample_idx += mi->sample_group * MCS_GROUP_RATES;
 602 +
 603 +       /*
 604 +        * When not using MRR, do not sample if the probability is already
 605 +        * higher than 95% to avoid wasting airtime
 606 +        */
 607 +       if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100)))
 608 +               return -1;
 609 +
 610 +       if (minstrel_get_duration(sample_idx) >
 611 +           minstrel_get_duration(mi->max_tp_rate)) {
 612 +               /*
 613 +                * Make sure that lower rates get sampled occasionally, even
 614 +                * if the link is working perfectly. Some drivers such as ath9k
 615 +                * severely limit aggregation size if the MRR chain contains low
 616 +                * rates
 617 +                *
 618 +                * If the lower rate has already been tried a few times, there's
 619 +                * no point in forcing it to be sampled again, so skip to the
 620 +                * next sampling index after applying this one in the tx control
 621 +                */
 622 +               if (mr->att_hist > 15) {
 623 +                       *defer = true;
 624 +                       minstrel_next_sample_idx(mi);
 625 +               }
 626 +       }
 627 +
 628 +       return sample_idx;
 629 +}
 630 +
 631 +static void
 632 +minstrel_aggr_check(struct minstrel_priv *mp, struct ieee80211_sta *pubsta, struct sk_buff *skb)
 633 +{
 634 +       struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 635 +       struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 636 +       u16 tid;
 637 +
 638 +       if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
 639 +               return;
 640 +
 641 +       if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
 642 +               return;
 643 +
 644 +       tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
 645 +       if (likely(sta->ampdu_mlme.tid_state_tx[tid] != HT_AGG_STATE_IDLE))
 646 +               return;
 647 +
 648 +       ieee80211_start_tx_ba_session(pubsta, tid);
 649 +}
 650 +
 651 +static void
 652 +minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
 653 +                     struct ieee80211_tx_rate_control *txrc)
 654 +{
 655 +       struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
 656 +       struct ieee80211_tx_rate *ar = info->status.rates;
 657 +       struct minstrel_ht_sta_priv *msp = priv_sta;
 658 +       struct minstrel_ht_sta *mi = &msp->ht;
 659 +       struct minstrel_priv *mp = priv;
 660 +       bool sample_defer = false;
 661 +       int sample_idx;
 662 +
 663 +       if (rate_control_send_low(sta, priv_sta, txrc))
 664 +               return;
 665 +
 666 +       if (!msp->is_ht)
 667 +               return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
 668 +
 669 +       minstrel_aggr_check(mp, sta, txrc->skb);
 670 +
 671 +       sample_idx = minstrel_get_sample_rate(mp, mi, &sample_defer);
 672 +       if (sample_idx >= 0) {
 673 +               if (sample_defer) {
 674 +                       minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
 675 +                               txrc, false, false);
 676 +                       minstrel_ht_set_rate(mp, mi, &ar[1], sample_idx,
 677 +                               txrc, true, true);
 678 +                       info->flags |= MINSTREL_INTFL_SAMPLE_SLOT1;
 679 +               } else {
 680 +                       minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
 681 +                               txrc, true, false);
 682 +                       minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
 683 +                               txrc, false, true);
 684 +                       info->flags |= MINSTREL_INTFL_SAMPLE_SLOT0;
 685 +               }
 686 +               mi->sample_pending++;
 687 +       } else {
 688 +               minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
 689 +                       txrc, false, false);
 690 +               minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2,
 691 +                       txrc, false, true);
 692 +       }
 693 +       minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, txrc, false, true);
 694 +
 695 +       ar[3].count = 0;
 696 +       ar[3].idx = -1;
 697 +
 698 +       mi->total_packets++;
 699 +
 700 +       /* wraparound */
 701 +       if (mi->total_packets >= 100000) {
 702 +               mi->total_packets = 0;
 703 +               mi->sample_packets = 0;
 704 +               mi->sample_pending = 0;
 705 +       }
 706 +}
 707 +
 708 +static void
 709 +minstrel_ht_update_cap(struct minstrel_ht_sta *mi, struct ieee80211_sta *sta,
 710 +                       enum nl80211_channel_type oper_chan_type)
 711 +{
 712 +       struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
 713 +       u16 sta_cap = sta->ht_cap.cap;
 714 +       int i;
 715 +
 716 +       if (oper_chan_type != NL80211_CHAN_HT40MINUS &&
 717 +           oper_chan_type != NL80211_CHAN_HT40PLUS)
 718 +               sta_cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
 719 +
 720 +       for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
 721 +               u16 req = 0;
 722 +
 723 +               mi->groups[i].supported = 0;
 724 +               if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
 725 +                       if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
 726 +                               req |= IEEE80211_HT_CAP_SGI_40;
 727 +                       else
 728 +                               req |= IEEE80211_HT_CAP_SGI_20;
 729 +               }
 730 +
 731 +               if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
 732 +                       req |= IEEE80211_HT_CAP_SUP_WIDTH_20_40;
 733 +
 734 +               if ((sta_cap & req) != req)
 735 +                       continue;
 736 +
 737 +               mi->groups[i].supported =
 738 +                       mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
 739 +       }
 740 +}
 741 +
 742 +static void
 743 +minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
 744 +                      struct ieee80211_sta *sta, void *priv_sta)
 745 +{
 746 +       struct minstrel_priv *mp = priv;
 747 +       struct minstrel_ht_sta_priv *msp = priv_sta;
 748 +       struct minstrel_ht_sta *mi = &msp->ht;
 749 +       struct ieee80211_local *local = hw_to_local(mp->hw);
 750 +       int ack_dur;
 751 +
 752 +       /* fall back to the old minstrel for legacy stations */
 753 +       if (sta && !sta->ht_cap.ht_supported) {
 754 +               msp->is_ht = false;
 755 +               memset(&msp->legacy, 0, sizeof(msp->legacy));
 756 +               msp->legacy.r = msp->ratelist;
 757 +               msp->legacy.sample_table = msp->sample_table;
 758 +               return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy);
 759 +       }
 760 +
 761 +       BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
 762 +               MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS);
 763 +
 764 +       msp->is_ht = true;
 765 +       memset(mi, 0, sizeof(*mi));
 766 +       mi->stats_update = jiffies;
 767 +
 768 +       ack_dur = ieee80211_frame_duration(local, 10, 60, 1, 1);
 769 +       mi->overhead = ieee80211_frame_duration(local, 0, 60, 1, 1) + ack_dur;
 770 +       mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
 771 +
 772 +       mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
 773 +
 774 +       minstrel_ht_update_cap(mi, sta, mp->hw->conf.channel_type);
 775 +}
 776 +
 777 +static void
 778 +minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
 779 +                        struct ieee80211_sta *sta, void *priv_sta,
 780 +                        u32 changed, enum nl80211_channel_type oper_chan_type)
 781 +{
 782 +       struct minstrel_ht_sta_priv *msp = priv_sta;
 783 +       struct minstrel_ht_sta *mi = &msp->ht;
 784 +
 785 +       minstrel_ht_update_cap(mi, sta, oper_chan_type);
 786 +}
 787 +
 788 +static void *
 789 +minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
 790 +{
 791 +       struct ieee80211_supported_band *sband;
 792 +       struct minstrel_ht_sta_priv *msp;
 793 +       struct minstrel_priv *mp = priv;
 794 +       struct ieee80211_hw *hw = mp->hw;
 795 +       int max_rates = 0;
 796 +       int i;
 797 +
 798 +       for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 799 +               sband = hw->wiphy->bands[i];
 800 +               if (sband && sband->n_bitrates > max_rates)
 801 +                       max_rates = sband->n_bitrates;
 802 +       }
 803 +
 804 +       msp = kzalloc(sizeof(struct minstrel_ht_sta), gfp);
 805 +       if (!msp)
 806 +               return NULL;
 807 +
 808 +       msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
 809 +       if (!msp->ratelist)
 810 +               goto error;
 811 +
 812 +       msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
 813 +       if (!msp->sample_table)
 814 +               goto error1;
 815 +
 816 +       return msp;
 817 +
 818 +error1:
 819 +       kfree(msp->sample_table);
 820 +error:
 821 +       kfree(msp);
 822 +       return NULL;
 823 +}
 824 +
 825 +static void
 826 +minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
 827 +{
 828 +       struct minstrel_ht_sta_priv *msp = priv_sta;
 829 +
 830 +       kfree(msp->sample_table);
 831 +       kfree(msp->ratelist);
 832 +       kfree(msp);
 833 +}
 834 +
 835 +static void *
 836 +minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
 837 +{
 838 +       return mac80211_minstrel.alloc(hw, debugfsdir);
 839 +}
 840 +
 841 +static void
 842 +minstrel_ht_free(void *priv)
 843 +{
 844 +       mac80211_minstrel.free(priv);
 845 +}
 846 +
 847 +static struct rate_control_ops mac80211_minstrel_ht = {
 848 +       .name = "minstrel_ht",
 849 +       .tx_status = minstrel_ht_tx_status,
 850 +       .get_rate = minstrel_ht_get_rate,
 851 +       .rate_init = minstrel_ht_rate_init,
 852 +       .rate_update = minstrel_ht_rate_update,
 853 +       .alloc_sta = minstrel_ht_alloc_sta,
 854 +       .free_sta = minstrel_ht_free_sta,
 855 +       .alloc = minstrel_ht_alloc,
 856 +       .free = minstrel_ht_free,
 857 +#ifdef CONFIG_MAC80211_DEBUGFS
 858 +       .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
 859 +       .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
 860 +#endif
 861 +};
 862 +
 863 +
 864 +static void
 865 +init_sample_table(void)
 866 +{
 867 +       int col, i, new_idx;
 868 +       u8 rnd[MCS_GROUP_RATES];
 869 +
 870 +       memset(sample_table, 0xff, sizeof(sample_table));
 871 +       for (col = 0; col < SAMPLE_COLUMNS; col++) {
 872 +               for (i = 0; i < MCS_GROUP_RATES; i++) {
 873 +                       get_random_bytes(rnd, sizeof(rnd));
 874 +                       new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
 875 +
 876 +                       while (sample_table[col][new_idx] != 0xff)
 877 +                               new_idx = (new_idx + 1) % MCS_GROUP_RATES;
 878 +
 879 +                       sample_table[col][new_idx] = i;
 880 +               }
 881 +       }
 882 +}
 883 +
 884 +int __init
 885 +rc80211_minstrel_ht_init(void)
 886 +{
 887 +       init_sample_table();
 888 +       return ieee80211_rate_control_register(&mac80211_minstrel_ht);
 889 +}
 890 +
 891 +void
 892 +rc80211_minstrel_ht_exit(void)
 893 +{
 894 +       ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
 895 +}
 896 --- /dev/null
 897 +++ b/net/mac80211/rc80211_minstrel_ht.h
 898 @@ -0,0 +1,115 @@
 899 +/*
 900 + * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
 901 + *
 902 + * This program is free software; you can redistribute it and/or modify
 903 + * it under the terms of the GNU General Public License version 2 as
 904 + * published by the Free Software Foundation.
 905 + */
 906 +
 907 +#ifndef __RC_MINSTREL_HT_H
 908 +#define __RC_MINSTREL_HT_H
 909 +
 910 +/*
 911 + * maximum number of spatial streams to make use of
 912 + * set this value to 3 once we have drivers that support it
 913 + */
 914 +#define MINSTREL_MAX_STREAMS   2
 915 +#define MINSTREL_STREAM_GROUPS 4
 916 +
 917 +/* scaled fraction values */
 918 +#define MINSTREL_SCALE 16
 919 +#define MINSTREL_FRAC(val, div) (((val) << MINSTREL_SCALE) / div)
 920 +#define MINSTREL_TRUNC(val) ((val) >> MINSTREL_SCALE)
 921 +
 922 +#define MCS_GROUP_RATES        8
 923 +
 924 +struct mcs_group {
 925 +       u32 flags;
 926 +       unsigned int streams;
 927 +       unsigned int duration[MCS_GROUP_RATES];
 928 +};
 929 +
 930 +struct minstrel_rate_stats {
 931 +       /* current / last sampling period attempts/success counters */
 932 +       unsigned int attempts, last_attempts;
 933 +       unsigned int success, last_success;
 934 +
 935 +       /* total attempts/success counters */
 936 +       u64 att_hist, succ_hist;
 937 +
 938 +       /* current throughput */
 939 +       unsigned int cur_tp;
 940 +
 941 +       /* packet delivery probabilities */
 942 +       unsigned int cur_prob, probability;
 943 +
 944 +       /* maximum retry counts */
 945 +       bool retry_updated;
 946 +       unsigned int retry_count;
 947 +       unsigned int retry_count_rtscts;
 948 +};
 949 +
 950 +struct minstrel_mcs_group_data {
 951 +       u8 index;
 952 +       u8 column;
 953 +
 954 +       /* bitfield of supported MCS rates of this group */
 955 +       u8 supported;
 956 +
 957 +       /* selected primary rates */
 958 +       unsigned int max_tp_rate;
 959 +       unsigned int max_tp_rate2;
 960 +       unsigned int max_prob_rate;
 961 +
 962 +       /* MCS rate statistics */
 963 +       struct minstrel_rate_stats rates[MCS_GROUP_RATES];
 964 +};
 965 +
 966 +struct minstrel_ht_sta {
 967 +       /* ampdu length average (EWMA) */
 968 +       unsigned int avg_ampdu_len;
 969 +
 970 +       /* best throughput rate */
 971 +       unsigned int max_tp_rate;
 972 +
 973 +       /* second best throughput rate */
 974 +       unsigned int max_tp_rate2;
 975 +
 976 +       /* best probability rate */
 977 +       unsigned int max_prob_rate;
 978 +
 979 +       /* time of last status update */
 980 +       unsigned long stats_update;
 981 +
 982 +       /* overhead time in usec for each frame */
 983 +       unsigned int overhead;
 984 +       unsigned int overhead_rtscts;
 985 +
 986 +       unsigned int total_packets;
 987 +       unsigned int sample_packets;
 988 +       unsigned int sample_pending;
 989 +
 990 +       /* current MCS group to be sampled */
 991 +       unsigned int sample_group;
 992 +
 993 +       /* MCS rate group info and statistics */
 994 +       struct minstrel_mcs_group_data groups[MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS];
 995 +};
 996 +
 997 +struct minstrel_ht_sta_priv {
 998 +       union {
 999 +               struct minstrel_ht_sta ht;
1000 +               struct minstrel_sta_info legacy;
1001 +       };
1002 +#ifdef CONFIG_MAC80211_DEBUGFS
1003 +       struct dentry *dbg_stats;
1004 +#endif
1005 +       void *ratelist;
1006 +       void *sample_table;
1007 +       bool is_ht;
1008 +};
1009 +
1010 +void minstrel_ht_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir);
1011 +void minstrel_ht_remove_sta_debugfs(void *priv, void *priv_sta);
1012 +
1013 +#endif
1014 --- /dev/null
1015 +++ b/net/mac80211/rc80211_minstrel_ht_debugfs.c
1016 @@ -0,0 +1,120 @@
1017 +/*
1018 + * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
1019 + *
1020 + * This program is free software; you can redistribute it and/or modify
1021 + * it under the terms of the GNU General Public License version 2 as
1022 + * published by the Free Software Foundation.
1023 + */
1024 +#include <linux/netdevice.h>
1025 +#include <linux/types.h>
1026 +#include <linux/skbuff.h>
1027 +#include <linux/debugfs.h>
1028 +#include <linux/ieee80211.h>
1029 +#include <net/mac80211.h>
1030 +#include "rc80211_minstrel.h"
1031 +#include "rc80211_minstrel_ht.h"
1032 +
1033 +extern const struct mcs_group minstrel_mcs_groups[];
1034 +
1035 +static int
1036 +minstrel_ht_stats_open(struct inode *inode, struct file *file)
1037 +{
1038 +       struct minstrel_ht_sta_priv *msp = inode->i_private;
1039 +       struct minstrel_ht_sta *mi = &msp->ht;
1040 +       struct minstrel_debugfs_info *ms;
1041 +       unsigned int i, j, tp, prob, eprob;
1042 +       char *p;
1043 +       int ret;
1044 +
1045 +       if (!msp->is_ht) {
1046 +               inode->i_private = &msp->legacy;
1047 +               ret = minstrel_stats_open(inode, file);
1048 +               inode->i_private = msp;
1049 +               return ret;
1050 +       }
1051 +
1052 +       ms = kmalloc(sizeof(*ms) + 8192, GFP_KERNEL);
1053 +       if (!ms)
1054 +               return -ENOMEM;
1055 +
1056 +       file->private_data = ms;
1057 +       p = ms->buf;
1058 +       p += sprintf(p, "type      rate     throughput  ewma prob   this prob  "
1059 +                       "this succ/attempt   success    attempts\n");
1060 +       for (i = 0; i < MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS; i++) {
1061 +               char htmode = '2';
1062 +               char gimode = 'L';
1063 +
1064 +               if (!mi->groups[i].supported)
1065 +                       continue;
1066 +
1067 +               if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
1068 +                       htmode = '4';
1069 +               if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI)
1070 +                       gimode = 'S';
1071 +
1072 +               for (j = 0; j < MCS_GROUP_RATES; j++) {
1073 +                       struct minstrel_rate_stats *mr = &mi->groups[i].rates[j];
1074 +                       int idx = i * MCS_GROUP_RATES + j;
1075 +
1076 +                       if (!mi->groups[i].supported & BIT(j))
1077 +                               continue;
1078 +
1079 +                       p += sprintf(p, "HT%c0/%cGI ", htmode, gimode);
1080 +
1081 +                       *(p++) = (idx == mi->max_tp_rate) ? 'T' : ' ';
1082 +                       *(p++) = (idx == mi->max_tp_rate2) ? 't' : ' ';
1083 +                       *(p++) = (idx == mi->max_prob_rate) ? 'P' : ' ';
1084 +                       p += sprintf(p, "MCS%-2u", (minstrel_mcs_groups[i].streams - 1) *
1085 +                                       MCS_GROUP_RATES + j);
1086 +
1087 +                       tp = mr->cur_tp / 10;
1088 +                       prob = MINSTREL_TRUNC(mr->cur_prob * 1000);
1089 +                       eprob = MINSTREL_TRUNC(mr->probability * 1000);
1090 +
1091 +                       p += sprintf(p, "  %6u.%1u   %6u.%1u   %6u.%1u        "
1092 +                                       "%3u(%3u)   %8llu    %8llu\n",
1093 +                                       tp / 10, tp % 10,
1094 +                                       eprob / 10, eprob % 10,
1095 +                                       prob / 10, prob % 10,
1096 +                                       mr->last_success,
1097 +                                       mr->last_attempts,
1098 +                                       (unsigned long long)mr->succ_hist,
1099 +                                       (unsigned long long)mr->att_hist);
1100 +               }
1101 +       }
1102 +       p += sprintf(p, "\nTotal packet count::    ideal %d      "
1103 +                       "lookaround %d\n",
1104 +                       max(0, (int) mi->total_packets - (int) mi->sample_packets),
1105 +                       mi->sample_packets);
1106 +       p += sprintf(p, "Average A-MPDU length: %d.%d\n",
1107 +               MINSTREL_TRUNC(mi->avg_ampdu_len),
1108 +               MINSTREL_TRUNC(mi->avg_ampdu_len * 10) % 10);
1109 +       ms->len = p - ms->buf;
1110 +
1111 +       return 0;
1112 +}
1113 +
1114 +static const struct file_operations minstrel_ht_stat_fops = {
1115 +       .owner = THIS_MODULE,
1116 +       .open = minstrel_ht_stats_open,
1117 +       .read = minstrel_stats_read,
1118 +       .release = minstrel_stats_release,
1119 +};
1120 +
1121 +void
1122 +minstrel_ht_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir)
1123 +{
1124 +       struct minstrel_ht_sta_priv *msp = priv_sta;
1125 +
1126 +       msp->dbg_stats = debugfs_create_file("rc_stats", S_IRUGO, dir, msp,
1127 +                       &minstrel_ht_stat_fops);
1128 +}
1129 +
1130 +void
1131 +minstrel_ht_remove_sta_debugfs(void *priv, void *priv_sta)
1132 +{
1133 +       struct minstrel_ht_sta_priv *msp = priv_sta;
1134 +
1135 +       debugfs_remove(msp->dbg_stats);
1136 +}