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 +1,815 @@
  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 +/*
 129 + * To enable sufficiently targeted rate sampling, MCS rates are divided into
 130 + * groups, based on the number of streams and flags (HT40, SGI) that they
 131 + * use.
 132 + */
 133 +const struct mcs_group minstrel_mcs_groups[] = {
 134 +       MCS_GROUP(1, 0, 0),
 135 +       MCS_GROUP(2, 0, 0),
 136 +#if MINSTREL_MAX_STREAMS >= 3
 137 +       MCS_GROUP(3, 0, 0),
 138 +#endif
 139 +
 140 +       MCS_GROUP(1, 1, 0),
 141 +       MCS_GROUP(2, 1, 0),
 142 +#if MINSTREL_MAX_STREAMS >= 3
 143 +       MCS_GROUP(3, 1, 0),
 144 +#endif
 145 +
 146 +       MCS_GROUP(1, 0, 1),
 147 +       MCS_GROUP(2, 0, 1),
 148 +#if MINSTREL_MAX_STREAMS >= 3
 149 +       MCS_GROUP(3, 0, 1),
 150 +#endif
 151 +
 152 +       MCS_GROUP(1, 1, 1),
 153 +       MCS_GROUP(2, 1, 1),
 154 +#if MINSTREL_MAX_STREAMS >= 3
 155 +       MCS_GROUP(3, 1, 1),
 156 +#endif
 157 +};
 158 +
 159 +static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES];
 160 +
 161 +/*
 162 + * Perform EWMA (Exponentially Weighted Moving Average) calculation
 163 + */
 164 +static int
 165 +minstrel_ewma(int old, int new, int weight)
 166 +{
 167 +       return (new * (100 - weight) + old * weight) / 100;
 168 +}
 169 +
 170 +/*
 171 + * Look up an MCS group index based on mac80211 rate information
 172 + */
 173 +static int
 174 +minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
 175 +{
 176 +       int streams = (rate->idx / MCS_GROUP_RATES) + 1;
 177 +       u32 flags = IEEE80211_TX_RC_SHORT_GI | IEEE80211_TX_RC_40_MHZ_WIDTH;
 178 +       int i;
 179 +
 180 +       for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) {
 181 +               if (minstrel_mcs_groups[i].streams != streams)
 182 +                       continue;
 183 +               if (minstrel_mcs_groups[i].flags != (rate->flags & flags))
 184 +                       continue;
 185 +
 186 +               return i;
 187 +       }
 188 +
 189 +       WARN_ON(1);
 190 +       return 0;
 191 +}
 192 +
 193 +static inline struct minstrel_rate_stats *
 194 +minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
 195 +{
 196 +       return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
 197 +}
 198 +
 199 +
 200 +/*
 201 + * Recalculate success probabilities and counters for a rate using EWMA
 202 + */
 203 +static void
 204 +minstrel_calc_rate_ewma(struct minstrel_priv *mp, struct minstrel_rate_stats *mr)
 205 +{
 206 +       if (unlikely(mr->attempts > 0)) {
 207 +               mr->sample_skipped = 0;
 208 +               mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
 209 +               if (!mr->att_hist)
 210 +                       mr->probability = mr->cur_prob;
 211 +               else
 212 +                       mr->probability = minstrel_ewma(mr->probability,
 213 +                               mr->cur_prob, EWMA_LEVEL);
 214 +               mr->att_hist += mr->attempts;
 215 +               mr->succ_hist += mr->success;
 216 +       } else {
 217 +               mr->sample_skipped++;
 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 +       if (mi->ampdu_packets > 0) {
 266 +               mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
 267 +                       MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
 268 +               mi->ampdu_len = 0;
 269 +               mi->ampdu_packets = 0;
 270 +       }
 271 +
 272 +       mi->sample_slow = 0;
 273 +       mi->sample_count = 0;
 274 +       mi->max_tp_rate = 0;
 275 +       mi->max_tp_rate2 = 0;
 276 +       mi->max_prob_rate = 0;
 277 +
 278 +       for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
 279 +               cur_prob = 0;
 280 +               cur_prob_tp = 0;
 281 +               cur_tp = 0;
 282 +               cur_tp2 = 0;
 283 +
 284 +               mg = &mi->groups[group];
 285 +               if (!mg->supported)
 286 +                       continue;
 287 +
 288 +               mg->max_tp_rate = 0;
 289 +               mg->max_tp_rate2 = 0;
 290 +               mg->max_prob_rate = 0;
 291 +               mi->sample_count++;
 292 +
 293 +               for (i = 0; i < MCS_GROUP_RATES; i++) {
 294 +                       if (!(mg->supported & BIT(i)))
 295 +                               continue;
 296 +
 297 +                       mr = &mg->rates[i];
 298 +                       mr->retry_updated = false;
 299 +                       index = MCS_GROUP_RATES * group + i;
 300 +                       minstrel_calc_rate_ewma(mp, mr);
 301 +                       minstrel_ht_calc_tp(mp, mi, group, i);
 302 +
 303 +                       if (!mr->cur_tp)
 304 +                               continue;
 305 +
 306 +                       /* ignore the lowest rate of each single-stream group */
 307 +                       if (!i && minstrel_mcs_groups[group].streams == 1)
 308 +                               continue;
 309 +
 310 +                       if ((mr->cur_tp > cur_prob_tp && mr->probability >
 311 +                            MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
 312 +                               mg->max_prob_rate = index;
 313 +                               cur_prob = mr->probability;
 314 +                       }
 315 +
 316 +                       if (mr->cur_tp > cur_tp) {
 317 +                               swap(index, mg->max_tp_rate);
 318 +                               cur_tp = mr->cur_tp;
 319 +                               mr = minstrel_get_ratestats(mi, index);
 320 +                       }
 321 +
 322 +                       if (index >= mg->max_tp_rate)
 323 +                               continue;
 324 +
 325 +                       if (mr->cur_tp > cur_tp2) {
 326 +                               mg->max_tp_rate2 = index;
 327 +                               cur_tp2 = mr->cur_tp;
 328 +                       }
 329 +               }
 330 +       }
 331 +
 332 +       /* try to sample up to half of the availble rates during each interval */
 333 +       mi->sample_count *= 4;
 334 +
 335 +       cur_prob = 0;
 336 +       cur_prob_tp = 0;
 337 +       cur_tp = 0;
 338 +       cur_tp2 = 0;
 339 +       for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
 340 +               mg = &mi->groups[group];
 341 +               if (!mg->supported)
 342 +                       continue;
 343 +
 344 +               mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
 345 +               if (cur_prob_tp < mr->cur_tp &&
 346 +                   minstrel_mcs_groups[group].streams == 1) {
 347 +                       mi->max_prob_rate = mg->max_prob_rate;
 348 +                       cur_prob = mr->cur_prob;
 349 +               }
 350 +
 351 +               mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
 352 +               if (cur_tp < mr->cur_tp) {
 353 +                       mi->max_tp_rate = mg->max_tp_rate;
 354 +                       cur_tp = mr->cur_tp;
 355 +               }
 356 +
 357 +               mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
 358 +               if (cur_tp2 < mr->cur_tp) {
 359 +                       mi->max_tp_rate2 = mg->max_tp_rate2;
 360 +                       cur_tp2 = mr->cur_tp;
 361 +               }
 362 +       }
 363 +
 364 +       mi->stats_update = jiffies;
 365 +}
 366 +
 367 +static bool
 368 +minstrel_ht_txstat_valid(struct ieee80211_tx_rate *rate)
 369 +{
 370 +       if (!rate->count)
 371 +               return false;
 372 +
 373 +       if (rate->idx < 0)
 374 +               return false;
 375 +
 376 +       return !!(rate->flags & IEEE80211_TX_RC_MCS);
 377 +}
 378 +
 379 +static void
 380 +minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
 381 +{
 382 +       struct minstrel_mcs_group_data *mg;
 383 +
 384 +       for (;;) {
 385 +               mi->sample_group++;
 386 +               mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
 387 +               mg = &mi->groups[mi->sample_group];
 388 +
 389 +               if (!mg->supported)
 390 +                       continue;
 391 +
 392 +               if (++mg->index > MCS_GROUP_RATES) {
 393 +                       mg->index = 0;
 394 +                       if (++mg->column > ARRAY_SIZE(sample_table))
 395 +                               mg->column = 0;
 396 +               }
 397 +               break;
 398 +       }
 399 +}
 400 +
 401 +static void
 402 +minstrel_downgrade_rate(struct minstrel_ht_sta *mi, int *idx, bool primary)
 403 +{
 404 +       int group, orig_group;
 405 +
 406 +       orig_group = group = *idx / MCS_GROUP_RATES;
 407 +       while (group > 0) {
 408 +               group--;
 409 +
 410 +               if (!mi->groups[group].supported)
 411 +                       continue;
 412 +
 413 +               if (minstrel_mcs_groups[group].streams >
 414 +                   minstrel_mcs_groups[orig_group].streams)
 415 +                       continue;
 416 +
 417 +               if (primary)
 418 +                       *idx = mi->groups[group].max_tp_rate;
 419 +               else
 420 +                       *idx = mi->groups[group].max_tp_rate2;
 421 +               break;
 422 +       }
 423 +}
 424 +
 425 +static void
 426 +minstrel_aggr_check(struct minstrel_priv *mp, struct ieee80211_sta *pubsta, struct sk_buff *skb)
 427 +{
 428 +       struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 429 +       struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 430 +       u16 tid;
 431 +
 432 +       if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
 433 +               return;
 434 +
 435 +       if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
 436 +               return;
 437 +
 438 +       tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
 439 +       if (likely(sta->ampdu_mlme.tid_state_tx[tid] != HT_AGG_STATE_IDLE))
 440 +               return;
 441 +
 442 +       ieee80211_start_tx_ba_session(pubsta, tid);
 443 +}
 444 +
 445 +static void
 446 +minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
 447 +                      struct ieee80211_sta *sta, void *priv_sta,
 448 +                      struct sk_buff *skb)
 449 +{
 450 +       struct minstrel_ht_sta_priv *msp = priv_sta;
 451 +       struct minstrel_ht_sta *mi = &msp->ht;
 452 +       struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 453 +       struct ieee80211_tx_rate *ar = info->status.rates;
 454 +       struct minstrel_rate_stats *rate, *rate2;
 455 +       struct minstrel_priv *mp = priv;
 456 +       bool last = false;
 457 +       int group;
 458 +       int i = 0;
 459 +
 460 +       if (!msp->is_ht)
 461 +               return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
 462 +
 463 +       /* This packet was aggregated but doesn't carry status info */
 464 +       if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
 465 +           !(info->flags & IEEE80211_TX_STAT_AMPDU))
 466 +               return;
 467 +
 468 +       if (!info->status.ampdu_len) {
 469 +               info->status.ampdu_ack_len = 1;
 470 +               info->status.ampdu_len = 1;
 471 +       }
 472 +
 473 +       mi->ampdu_packets++;
 474 +       mi->ampdu_len += info->status.ampdu_len;
 475 +
 476 +       if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
 477 +               mi->sample_wait = 4 + MINSTREL_TRUNC(mi->avg_ampdu_len);
 478 +               mi->sample_tries = 3;
 479 +               mi->sample_count--;
 480 +       }
 481 +
 482 +       if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) {
 483 +               mi->sample_packets += info->status.ampdu_len;
 484 +               minstrel_next_sample_idx(mi);
 485 +       }
 486 +
 487 +       for (i = 0; !last; i++) {
 488 +               last = (i == IEEE80211_TX_MAX_RATES - 1) ||
 489 +                      !minstrel_ht_txstat_valid(&ar[i + 1]);
 490 +
 491 +               if (!minstrel_ht_txstat_valid(&ar[i]))
 492 +                       break;
 493 +
 494 +               group = minstrel_ht_get_group_idx(&ar[i]);
 495 +               rate = &mi->groups[group].rates[ar[i].idx % 8];
 496 +
 497 +               if (last && (info->flags & IEEE80211_TX_STAT_ACK))
 498 +                       rate->success += info->status.ampdu_ack_len;
 499 +
 500 +               rate->attempts += ar[i].count * info->status.ampdu_len;
 501 +       }
 502 +
 503 +       /*
 504 +        * check for sudden death of spatial multiplexing,
 505 +        * downgrade to a lower number of streams if necessary.
 506 +        */
 507 +       rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
 508 +       if (rate->attempts > 30 &&
 509 +           MINSTREL_FRAC(rate->success, rate->attempts) <
 510 +           MINSTREL_FRAC(20, 100))
 511 +               minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
 512 +
 513 +       rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
 514 +       if (rate->attempts > 30 &&
 515 +           MINSTREL_FRAC(rate->success, rate->attempts) <
 516 +           MINSTREL_FRAC(20, 100))
 517 +               minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
 518 +
 519 +       if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
 520 +               minstrel_ht_update_stats(mp, mi);
 521 +               minstrel_aggr_check(mp, sta, skb);
 522 +       }
 523 +}
 524 +
 525 +static void
 526 +minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
 527 +                         int index)
 528 +{
 529 +       struct minstrel_rate_stats *mr;
 530 +       const struct mcs_group *group;
 531 +       unsigned int tx_time, tx_time_rtscts, tx_time_data;
 532 +       unsigned int cw = mp->cw_min;
 533 +       unsigned int t_slot = 9; /* FIXME */
 534 +       unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
 535 +
 536 +       mr = minstrel_get_ratestats(mi, index);
 537 +       if (mr->probability < MINSTREL_FRAC(1, 10)) {
 538 +               mr->retry_count = 1;
 539 +               mr->retry_count_rtscts = 1;
 540 +               return;
 541 +       }
 542 +
 543 +       mr->retry_count = 2;
 544 +       mr->retry_count_rtscts = 2;
 545 +       mr->retry_updated = true;
 546 +
 547 +       group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
 548 +       tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len;
 549 +       tx_time = 2 * (t_slot + mi->overhead + tx_time_data);
 550 +       tx_time_rtscts = 2 * (t_slot + mi->overhead_rtscts + tx_time_data);
 551 +       do {
 552 +               cw = (cw << 1) | 1;
 553 +               cw = min(cw, mp->cw_max);
 554 +               tx_time += cw + t_slot + mi->overhead;
 555 +               tx_time_rtscts += cw + t_slot + mi->overhead_rtscts;
 556 +               if (tx_time_rtscts < mp->segment_size)
 557 +                       mr->retry_count_rtscts++;
 558 +       } while ((tx_time < mp->segment_size) &&
 559 +                (++mr->retry_count < mp->max_retry));
 560 +}
 561 +
 562 +
 563 +static void
 564 +minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
 565 +                     struct ieee80211_tx_rate *rate, int index,
 566 +                     struct ieee80211_tx_rate_control *txrc,
 567 +                     bool sample, bool rtscts)
 568 +{
 569 +       const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
 570 +       struct minstrel_rate_stats *mr;
 571 +
 572 +       mr = minstrel_get_ratestats(mi, index);
 573 +       if (!mr->retry_updated)
 574 +               minstrel_calc_retransmit(mp, mi, index);
 575 +
 576 +       if (mr->probability < MINSTREL_FRAC(20, 100))
 577 +               rate->count = 2;
 578 +       else if (rtscts)
 579 +               rate->count = mr->retry_count_rtscts;
 580 +       else
 581 +               rate->count = mr->retry_count;
 582 +
 583 +       rate->flags = IEEE80211_TX_RC_MCS | group->flags;
 584 +       if (txrc->short_preamble)
 585 +               rate->flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
 586 +       if (txrc->rts || rtscts)
 587 +               rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS;
 588 +       rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES;
 589 +}
 590 +
 591 +static inline int
 592 +minstrel_get_duration(int index)
 593 +{
 594 +       const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
 595 +       return group->duration[index % MCS_GROUP_RATES];
 596 +}
 597 +
 598 +static int
 599 +minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 600 +{
 601 +       struct minstrel_rate_stats *mr;
 602 +       struct minstrel_mcs_group_data *mg;
 603 +       int sample_idx = 0;
 604 +
 605 +       if (mi->sample_wait > 0) {
 606 +               mi->sample_wait--;
 607 +               return -1;
 608 +       }
 609 +
 610 +       if (!mi->sample_tries)
 611 +               return -1;
 612 +
 613 +       mi->sample_tries--;
 614 +       mg = &mi->groups[mi->sample_group];
 615 +       sample_idx = sample_table[mg->column][mg->index];
 616 +       mr = &mg->rates[sample_idx];
 617 +       sample_idx += mi->sample_group * MCS_GROUP_RATES;
 618 +
 619 +       /*
 620 +        * When not using MRR, do not sample if the probability is already
 621 +        * higher than 95% to avoid wasting airtime
 622 +        */
 623 +       if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100)))
 624 +               goto next;
 625 +
 626 +       /*
 627 +        * Make sure that lower rates get sampled only occasionally,
 628 +        * if the link is working perfectly.
 629 +        */
 630 +       if (minstrel_get_duration(sample_idx) >
 631 +           minstrel_get_duration(mi->max_tp_rate)) {
 632 +               if (mr->sample_skipped < 10)
 633 +                       goto next;
 634 +
 635 +               if (mi->sample_slow++ > 2)
 636 +                       goto next;
 637 +       }
 638 +
 639 +       return sample_idx;
 640 +
 641 +next:
 642 +       minstrel_next_sample_idx(mi);
 643 +       return -1;
 644 +}
 645 +
 646 +static void
 647 +minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
 648 +                     struct ieee80211_tx_rate_control *txrc)
 649 +{
 650 +       struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
 651 +       struct ieee80211_tx_rate *ar = info->status.rates;
 652 +       struct minstrel_ht_sta_priv *msp = priv_sta;
 653 +       struct minstrel_ht_sta *mi = &msp->ht;
 654 +       struct minstrel_priv *mp = priv;
 655 +       int sample_idx;
 656 +
 657 +       if (rate_control_send_low(sta, priv_sta, txrc))
 658 +               return;
 659 +
 660 +       if (!msp->is_ht)
 661 +               return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
 662 +
 663 +       sample_idx = minstrel_get_sample_rate(mp, mi);
 664 +       if (sample_idx >= 0) {
 665 +               minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
 666 +                       txrc, true, false);
 667 +               minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
 668 +                       txrc, false, true);
 669 +               info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
 670 +       } else {
 671 +               minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
 672 +                       txrc, false, false);
 673 +               minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2,
 674 +                       txrc, false, true);
 675 +       }
 676 +       minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, txrc, false, true);
 677 +
 678 +       ar[3].count = 0;
 679 +       ar[3].idx = -1;
 680 +
 681 +       mi->total_packets++;
 682 +
 683 +       /* wraparound */
 684 +       if (mi->total_packets == ~0) {
 685 +               mi->total_packets = 0;
 686 +               mi->sample_packets = 0;
 687 +       }
 688 +}
 689 +
 690 +static void
 691 +minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
 692 +                        struct ieee80211_sta *sta, void *priv_sta,
 693 +                       enum nl80211_channel_type oper_chan_type)
 694 +{
 695 +       struct minstrel_priv *mp = priv;
 696 +       struct minstrel_ht_sta_priv *msp = priv_sta;
 697 +       struct minstrel_ht_sta *mi = &msp->ht;
 698 +       struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
 699 +       struct ieee80211_local *local = hw_to_local(mp->hw);
 700 +       u16 sta_cap = sta->ht_cap.cap;
 701 +       int ack_dur;
 702 +       int i;
 703 +
 704 +       /* fall back to the old minstrel for legacy stations */
 705 +       if (sta && !sta->ht_cap.ht_supported) {
 706 +               msp->is_ht = false;
 707 +               memset(&msp->legacy, 0, sizeof(msp->legacy));
 708 +               msp->legacy.r = msp->ratelist;
 709 +               msp->legacy.sample_table = msp->sample_table;
 710 +               return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy);
 711 +       }
 712 +
 713 +       BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
 714 +               MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS);
 715 +
 716 +       msp->is_ht = true;
 717 +       memset(mi, 0, sizeof(*mi));
 718 +       mi->stats_update = jiffies;
 719 +
 720 +       ack_dur = ieee80211_frame_duration(local, 10, 60, 1, 1);
 721 +       mi->overhead = ieee80211_frame_duration(local, 0, 60, 1, 1) + ack_dur;
 722 +       mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
 723 +
 724 +       mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
 725 +
 726 +       /* When using MRR, sample more on the first attempt, without delay */
 727 +       if (mp->has_mrr) {
 728 +               mi->sample_count = 16;
 729 +               mi->sample_wait = 0;
 730 +       } else {
 731 +               mi->sample_count = 8;
 732 +               mi->sample_wait = 8;
 733 +       }
 734 +       mi->sample_tries = 4;
 735 +
 736 +       if (oper_chan_type != NL80211_CHAN_HT40MINUS &&
 737 +           oper_chan_type != NL80211_CHAN_HT40PLUS)
 738 +               sta_cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
 739 +
 740 +       for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
 741 +               u16 req = 0;
 742 +
 743 +               mi->groups[i].supported = 0;
 744 +               if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
 745 +                       if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
 746 +                               req |= IEEE80211_HT_CAP_SGI_40;
 747 +                       else
 748 +                               req |= IEEE80211_HT_CAP_SGI_20;
 749 +               }
 750 +
 751 +               if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
 752 +                       req |= IEEE80211_HT_CAP_SUP_WIDTH_20_40;
 753 +
 754 +               if ((sta_cap & req) != req)
 755 +                       continue;
 756 +
 757 +               mi->groups[i].supported =
 758 +                       mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
 759 +       }
 760 +}
 761 +
 762 +static void
 763 +minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
 764 +                      struct ieee80211_sta *sta, void *priv_sta)
 765 +{
 766 +       struct minstrel_priv *mp = priv;
 767 +
 768 +       minstrel_ht_update_caps(priv, sband, sta, priv_sta, mp->hw->conf.channel_type);
 769 +}
 770 +
 771 +static void
 772 +minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
 773 +                        struct ieee80211_sta *sta, void *priv_sta,
 774 +                        u32 changed, enum nl80211_channel_type oper_chan_type)
 775 +{
 776 +       minstrel_ht_update_caps(priv, sband, sta, priv_sta, oper_chan_type);
 777 +}
 778 +
 779 +static void *
 780 +minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
 781 +{
 782 +       struct ieee80211_supported_band *sband;
 783 +       struct minstrel_ht_sta_priv *msp;
 784 +       struct minstrel_priv *mp = priv;
 785 +       struct ieee80211_hw *hw = mp->hw;
 786 +       int max_rates = 0;
 787 +       int i;
 788 +
 789 +       for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 790 +               sband = hw->wiphy->bands[i];
 791 +               if (sband && sband->n_bitrates > max_rates)
 792 +                       max_rates = sband->n_bitrates;
 793 +       }
 794 +
 795 +       msp = kzalloc(sizeof(struct minstrel_ht_sta), gfp);
 796 +       if (!msp)
 797 +               return NULL;
 798 +
 799 +       msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
 800 +       if (!msp->ratelist)
 801 +               goto error;
 802 +
 803 +       msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
 804 +       if (!msp->sample_table)
 805 +               goto error1;
 806 +
 807 +       return msp;
 808 +
 809 +error1:
 810 +       kfree(msp->sample_table);
 811 +error:
 812 +       kfree(msp);
 813 +       return NULL;
 814 +}
 815 +
 816 +static void
 817 +minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
 818 +{
 819 +       struct minstrel_ht_sta_priv *msp = priv_sta;
 820 +
 821 +       kfree(msp->sample_table);
 822 +       kfree(msp->ratelist);
 823 +       kfree(msp);
 824 +}
 825 +
 826 +static void *
 827 +minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
 828 +{
 829 +       return mac80211_minstrel.alloc(hw, debugfsdir);
 830 +}
 831 +
 832 +static void
 833 +minstrel_ht_free(void *priv)
 834 +{
 835 +       mac80211_minstrel.free(priv);
 836 +}
 837 +
 838 +static struct rate_control_ops mac80211_minstrel_ht = {
 839 +       .name = "minstrel_ht",
 840 +       .tx_status = minstrel_ht_tx_status,
 841 +       .get_rate = minstrel_ht_get_rate,
 842 +       .rate_init = minstrel_ht_rate_init,
 843 +       .rate_update = minstrel_ht_rate_update,
 844 +       .alloc_sta = minstrel_ht_alloc_sta,
 845 +       .free_sta = minstrel_ht_free_sta,
 846 +       .alloc = minstrel_ht_alloc,
 847 +       .free = minstrel_ht_free,
 848 +#ifdef CONFIG_MAC80211_DEBUGFS
 849 +       .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
 850 +       .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
 851 +#endif
 852 +};
 853 +
 854 +
 855 +static void
 856 +init_sample_table(void)
 857 +{
 858 +       int col, i, new_idx;
 859 +       u8 rnd[MCS_GROUP_RATES];
 860 +
 861 +       memset(sample_table, 0xff, sizeof(sample_table));
 862 +       for (col = 0; col < SAMPLE_COLUMNS; col++) {
 863 +               for (i = 0; i < MCS_GROUP_RATES; i++) {
 864 +                       get_random_bytes(rnd, sizeof(rnd));
 865 +                       new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
 866 +
 867 +                       while (sample_table[col][new_idx] != 0xff)
 868 +                               new_idx = (new_idx + 1) % MCS_GROUP_RATES;
 869 +
 870 +                       sample_table[col][new_idx] = i;
 871 +               }
 872 +       }
 873 +}
 874 +
 875 +int __init
 876 +rc80211_minstrel_ht_init(void)
 877 +{
 878 +       init_sample_table();
 879 +       return ieee80211_rate_control_register(&mac80211_minstrel_ht);
 880 +}
 881 +
 882 +void
 883 +rc80211_minstrel_ht_exit(void)
 884 +{
 885 +       ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
 886 +}
 887 --- /dev/null
 888 +++ b/net/mac80211/rc80211_minstrel_ht.h
 889 @@ -0,0 +1,125 @@
 890 +/*
 891 + * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
 892 + *
 893 + * This program is free software; you can redistribute it and/or modify
 894 + * it under the terms of the GNU General Public License version 2 as
 895 + * published by the Free Software Foundation.
 896 + */
 897 +
 898 +#ifndef __RC_MINSTREL_HT_H
 899 +#define __RC_MINSTREL_HT_H
 900 +
 901 +/*
 902 + * maximum number of spatial streams to make use of
 903 + * set this value to 3 once we have drivers that support it
 904 + */
 905 +#define MINSTREL_MAX_STREAMS   2
 906 +#define MINSTREL_STREAM_GROUPS 4
 907 +
 908 +/* scaled fraction values */
 909 +#define MINSTREL_SCALE 16
 910 +#define MINSTREL_FRAC(val, div) (((val) << MINSTREL_SCALE) / div)
 911 +#define MINSTREL_TRUNC(val) ((val) >> MINSTREL_SCALE)
 912 +
 913 +#define MCS_GROUP_RATES        8
 914 +
 915 +struct mcs_group {
 916 +       u32 flags;
 917 +       unsigned int streams;
 918 +       unsigned int duration[MCS_GROUP_RATES];
 919 +};
 920 +
 921 +struct minstrel_rate_stats {
 922 +       /* current / last sampling period attempts/success counters */
 923 +       unsigned int attempts, last_attempts;
 924 +       unsigned int success, last_success;
 925 +
 926 +       /* total attempts/success counters */
 927 +       u64 att_hist, succ_hist;
 928 +
 929 +       /* current throughput */
 930 +       unsigned int cur_tp;
 931 +
 932 +       /* packet delivery probabilities */
 933 +       unsigned int cur_prob, probability;
 934 +
 935 +       /* maximum retry counts */
 936 +       unsigned int retry_count;
 937 +       unsigned int retry_count_rtscts;
 938 +
 939 +       bool retry_updated;
 940 +       u8 sample_skipped;
 941 +};
 942 +
 943 +struct minstrel_mcs_group_data {
 944 +       u8 index;
 945 +       u8 column;
 946 +
 947 +       /* bitfield of supported MCS rates of this group */
 948 +       u8 supported;
 949 +
 950 +       /* selected primary rates */
 951 +       unsigned int max_tp_rate;
 952 +       unsigned int max_tp_rate2;
 953 +       unsigned int max_prob_rate;
 954 +
 955 +       /* MCS rate statistics */
 956 +       struct minstrel_rate_stats rates[MCS_GROUP_RATES];
 957 +};
 958 +
 959 +struct minstrel_ht_sta {
 960 +       /* ampdu length (average, per sampling interval) */
 961 +       unsigned int ampdu_len;
 962 +       unsigned int ampdu_packets;
 963 +
 964 +       /* ampdu length (EWMA) */
 965 +       unsigned int avg_ampdu_len;
 966 +
 967 +       /* best throughput rate */
 968 +       unsigned int max_tp_rate;
 969 +
 970 +       /* second best throughput rate */
 971 +       unsigned int max_tp_rate2;
 972 +
 973 +       /* best probability rate */
 974 +       unsigned int max_prob_rate;
 975 +
 976 +       /* time of last status update */
 977 +       unsigned long stats_update;
 978 +
 979 +       /* overhead time in usec for each frame */
 980 +       unsigned int overhead;
 981 +       unsigned int overhead_rtscts;
 982 +
 983 +       unsigned int total_packets;
 984 +       unsigned int sample_packets;
 985 +
 986 +       u8 sample_wait;
 987 +       u8 sample_tries;
 988 +       u8 sample_count;
 989 +       u8 sample_slow;
 990 +
 991 +       /* current MCS group to be sampled */
 992 +       u8 sample_group;
 993 +
 994 +       /* MCS rate group info and statistics */
 995 +       struct minstrel_mcs_group_data groups[MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS];
 996 +};
 997 +
 998 +struct minstrel_ht_sta_priv {
 999 +       union {
1000 +               struct minstrel_ht_sta ht;
1001 +               struct minstrel_sta_info legacy;
1002 +       };
1003 +#ifdef CONFIG_MAC80211_DEBUGFS
1004 +       struct dentry *dbg_stats;
1005 +#endif
1006 +       void *ratelist;
1007 +       void *sample_table;
1008 +       bool is_ht;
1009 +};
1010 +
1011 +void minstrel_ht_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir);
1012 +void minstrel_ht_remove_sta_debugfs(void *priv, void *priv_sta);
1013 +
1014 +#endif
1015 --- /dev/null
1016 +++ b/net/mac80211/rc80211_minstrel_ht_debugfs.c
1017 @@ -0,0 +1,120 @@
1018 +/*
1019 + * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
1020 + *
1021 + * This program is free software; you can redistribute it and/or modify
1022 + * it under the terms of the GNU General Public License version 2 as
1023 + * published by the Free Software Foundation.
1024 + */
1025 +#include <linux/netdevice.h>
1026 +#include <linux/types.h>
1027 +#include <linux/skbuff.h>
1028 +#include <linux/debugfs.h>
1029 +#include <linux/ieee80211.h>
1030 +#include <net/mac80211.h>
1031 +#include "rc80211_minstrel.h"
1032 +#include "rc80211_minstrel_ht.h"
1033 +
1034 +extern const struct mcs_group minstrel_mcs_groups[];
1035 +
1036 +static int
1037 +minstrel_ht_stats_open(struct inode *inode, struct file *file)
1038 +{
1039 +       struct minstrel_ht_sta_priv *msp = inode->i_private;
1040 +       struct minstrel_ht_sta *mi = &msp->ht;
1041 +       struct minstrel_debugfs_info *ms;
1042 +       unsigned int i, j, tp, prob, eprob;
1043 +       char *p;
1044 +       int ret;
1045 +
1046 +       if (!msp->is_ht) {
1047 +               inode->i_private = &msp->legacy;
1048 +               ret = minstrel_stats_open(inode, file);
1049 +               inode->i_private = msp;
1050 +               return ret;
1051 +       }
1052 +
1053 +       ms = kmalloc(sizeof(*ms) + 8192, GFP_KERNEL);
1054 +       if (!ms)
1055 +               return -ENOMEM;
1056 +
1057 +       file->private_data = ms;
1058 +       p = ms->buf;
1059 +       p += sprintf(p, "type      rate     throughput  ewma prob   this prob  "
1060 +                       "this succ/attempt   success    attempts\n");
1061 +       for (i = 0; i < MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS; i++) {
1062 +               char htmode = '2';
1063 +               char gimode = 'L';
1064 +
1065 +               if (!mi->groups[i].supported)
1066 +                       continue;
1067 +
1068 +               if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
1069 +                       htmode = '4';
1070 +               if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI)
1071 +                       gimode = 'S';
1072 +
1073 +               for (j = 0; j < MCS_GROUP_RATES; j++) {
1074 +                       struct minstrel_rate_stats *mr = &mi->groups[i].rates[j];
1075 +                       int idx = i * MCS_GROUP_RATES + j;
1076 +
1077 +                       if (!(mi->groups[i].supported & BIT(j)))
1078 +                               continue;
1079 +
1080 +                       p += sprintf(p, "HT%c0/%cGI ", htmode, gimode);
1081 +
1082 +                       *(p++) = (idx == mi->max_tp_rate) ? 'T' : ' ';
1083 +                       *(p++) = (idx == mi->max_tp_rate2) ? 't' : ' ';
1084 +                       *(p++) = (idx == mi->max_prob_rate) ? 'P' : ' ';
1085 +                       p += sprintf(p, "MCS%-2u", (minstrel_mcs_groups[i].streams - 1) *
1086 +                                       MCS_GROUP_RATES + j);
1087 +
1088 +                       tp = mr->cur_tp / 10;
1089 +                       prob = MINSTREL_TRUNC(mr->cur_prob * 1000);
1090 +                       eprob = MINSTREL_TRUNC(mr->probability * 1000);
1091 +
1092 +                       p += sprintf(p, "  %6u.%1u   %6u.%1u   %6u.%1u        "
1093 +                                       "%3u(%3u)   %8llu    %8llu\n",
1094 +                                       tp / 10, tp % 10,
1095 +                                       eprob / 10, eprob % 10,
1096 +                                       prob / 10, prob % 10,
1097 +                                       mr->last_success,
1098 +                                       mr->last_attempts,
1099 +                                       (unsigned long long)mr->succ_hist,
1100 +                                       (unsigned long long)mr->att_hist);
1101 +               }
1102 +       }
1103 +       p += sprintf(p, "\nTotal packet count::    ideal %d      "
1104 +                       "lookaround %d\n",
1105 +                       max(0, (int) mi->total_packets - (int) mi->sample_packets),
1106 +                       mi->sample_packets);
1107 +       p += sprintf(p, "Average A-MPDU length: %d.%d\n",
1108 +               MINSTREL_TRUNC(mi->avg_ampdu_len),
1109 +               MINSTREL_TRUNC(mi->avg_ampdu_len * 10) % 10);
1110 +       ms->len = p - ms->buf;
1111 +
1112 +       return 0;
1113 +}
1114 +
1115 +static const struct file_operations minstrel_ht_stat_fops = {
1116 +       .owner = THIS_MODULE,
1117 +       .open = minstrel_ht_stats_open,
1118 +       .read = minstrel_stats_read,
1119 +       .release = minstrel_stats_release,
1120 +};
1121 +
1122 +void
1123 +minstrel_ht_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir)
1124 +{
1125 +       struct minstrel_ht_sta_priv *msp = priv_sta;
1126 +
1127 +       msp->dbg_stats = debugfs_create_file("rc_stats", S_IRUGO, dir, msp,
1128 +                       &minstrel_ht_stat_fops);
1129 +}
1130 +
1131 +void
1132 +minstrel_ht_remove_sta_debugfs(void *priv, void *priv_sta)
1133 +{
1134 +       struct minstrel_ht_sta_priv *msp = priv_sta;
1135 +
1136 +       debugfs_remove(msp->dbg_stats);
1137 +}