root/net/mac80211/rc80211_minstrel_ht.c

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DEFINITIONS

This source file includes following definitions.
  1. minstrel_get_valid_vht_rates
  2. minstrel_ht_get_group_idx
  3. minstrel_vht_get_group_idx
  4. minstrel_ht_get_stats
  5. minstrel_get_ratestats
  6. minstrel_ht_avg_ampdu_len
  7. minstrel_ht_get_tp_avg
  8. minstrel_ht_sort_best_tp_rates
  9. minstrel_ht_set_best_prob_rate
  10. minstrel_ht_assign_best_tp_rates
  11. minstrel_ht_prob_rate_reduce_streams
  12. minstrel_get_duration
  13. minstrel_ht_probe_group
  14. minstrel_ht_find_probe_rates
  15. minstrel_ht_rate_sample_switch
  16. minstrel_ht_update_stats
  17. minstrel_ht_txstat_valid
  18. minstrel_set_next_sample_idx
  19. minstrel_downgrade_rate
  20. minstrel_aggr_check
  21. minstrel_ht_tx_status
  22. minstrel_calc_retransmit
  23. minstrel_ht_set_rate
  24. minstrel_ht_get_prob_ewma
  25. minstrel_ht_get_max_amsdu_len
  26. minstrel_ht_update_rates
  27. minstrel_get_sample_rate
  28. minstrel_ht_get_rate
  29. minstrel_ht_update_cck
  30. minstrel_ht_update_caps
  31. minstrel_ht_rate_init
  32. minstrel_ht_rate_update
  33. minstrel_ht_alloc_sta
  34. minstrel_ht_free_sta
  35. minstrel_ht_init_cck_rates
  36. minstrel_ht_alloc
  37. minstrel_ht_add_debugfs
  38. minstrel_ht_free
  39. minstrel_ht_get_expected_throughput
  40. init_sample_table
  41. rc80211_minstrel_init
  42. rc80211_minstrel_exit

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>
   4  */
   5 #include <linux/netdevice.h>
   6 #include <linux/types.h>
   7 #include <linux/skbuff.h>
   8 #include <linux/debugfs.h>
   9 #include <linux/random.h>
  10 #include <linux/moduleparam.h>
  11 #include <linux/ieee80211.h>
  12 #include <net/mac80211.h>
  13 #include "rate.h"
  14 #include "sta_info.h"
  15 #include "rc80211_minstrel.h"
  16 #include "rc80211_minstrel_ht.h"
  17 
  18 #define AVG_AMPDU_SIZE  16
  19 #define AVG_PKT_SIZE    1200
  20 
  21 #define SAMPLE_SWITCH_THR       100
  22 
  23 /* Number of bits for an average sized packet */
  24 #define MCS_NBITS ((AVG_PKT_SIZE * AVG_AMPDU_SIZE) << 3)
  25 
  26 /* Number of symbols for a packet with (bps) bits per symbol */
  27 #define MCS_NSYMS(bps) DIV_ROUND_UP(MCS_NBITS, (bps))
  28 
  29 /* Transmission time (nanoseconds) for a packet containing (syms) symbols */
  30 #define MCS_SYMBOL_TIME(sgi, syms)                                      \
  31         (sgi ?                                                          \
  32           ((syms) * 18000 + 4000) / 5 : /* syms * 3.6 us */             \
  33           ((syms) * 1000) << 2          /* syms * 4 us */               \
  34         )
  35 
  36 /* Transmit duration for the raw data part of an average sized packet */
  37 #define MCS_DURATION(streams, sgi, bps) \
  38         (MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps))) / AVG_AMPDU_SIZE)
  39 
  40 #define BW_20                   0
  41 #define BW_40                   1
  42 #define BW_80                   2
  43 
  44 /*
  45  * Define group sort order: HT40 -> SGI -> #streams
  46  */
  47 #define GROUP_IDX(_streams, _sgi, _ht40)        \
  48         MINSTREL_HT_GROUP_0 +                   \
  49         MINSTREL_MAX_STREAMS * 2 * _ht40 +      \
  50         MINSTREL_MAX_STREAMS * _sgi +   \
  51         _streams - 1
  52 
  53 #define _MAX(a, b) (((a)>(b))?(a):(b))
  54 
  55 #define GROUP_SHIFT(duration)                                           \
  56         _MAX(0, 16 - __builtin_clz(duration))
  57 
  58 /* MCS rate information for an MCS group */
  59 #define __MCS_GROUP(_streams, _sgi, _ht40, _s)                          \
  60         [GROUP_IDX(_streams, _sgi, _ht40)] = {                          \
  61         .streams = _streams,                                            \
  62         .shift = _s,                                                    \
  63         .bw = _ht40,                                                    \
  64         .flags =                                                        \
  65                 IEEE80211_TX_RC_MCS |                                   \
  66                 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |                 \
  67                 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),             \
  68         .duration = {                                                   \
  69                 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26) >> _s,    \
  70                 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52) >> _s,   \
  71                 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78) >> _s,   \
  72                 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104) >> _s,  \
  73                 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156) >> _s,  \
  74                 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208) >> _s,  \
  75                 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234) >> _s,  \
  76                 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) >> _s   \
  77         }                                                               \
  78 }
  79 
  80 #define MCS_GROUP_SHIFT(_streams, _sgi, _ht40)                          \
  81         GROUP_SHIFT(MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26))
  82 
  83 #define MCS_GROUP(_streams, _sgi, _ht40)                                \
  84         __MCS_GROUP(_streams, _sgi, _ht40,                              \
  85                     MCS_GROUP_SHIFT(_streams, _sgi, _ht40))
  86 
  87 #define VHT_GROUP_IDX(_streams, _sgi, _bw)                              \
  88         (MINSTREL_VHT_GROUP_0 +                                         \
  89          MINSTREL_MAX_STREAMS * 2 * (_bw) +                             \
  90          MINSTREL_MAX_STREAMS * (_sgi) +                                \
  91          (_streams) - 1)
  92 
  93 #define BW2VBPS(_bw, r3, r2, r1)                                        \
  94         (_bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)
  95 
  96 #define __VHT_GROUP(_streams, _sgi, _bw, _s)                            \
  97         [VHT_GROUP_IDX(_streams, _sgi, _bw)] = {                        \
  98         .streams = _streams,                                            \
  99         .shift = _s,                                                    \
 100         .bw = _bw,                                                      \
 101         .flags =                                                        \
 102                 IEEE80211_TX_RC_VHT_MCS |                               \
 103                 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |                 \
 104                 (_bw == BW_80 ? IEEE80211_TX_RC_80_MHZ_WIDTH :          \
 105                  _bw == BW_40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),      \
 106         .duration = {                                                   \
 107                 MCS_DURATION(_streams, _sgi,                            \
 108                              BW2VBPS(_bw,  117,  54,  26)) >> _s,       \
 109                 MCS_DURATION(_streams, _sgi,                            \
 110                              BW2VBPS(_bw,  234, 108,  52)) >> _s,       \
 111                 MCS_DURATION(_streams, _sgi,                            \
 112                              BW2VBPS(_bw,  351, 162,  78)) >> _s,       \
 113                 MCS_DURATION(_streams, _sgi,                            \
 114                              BW2VBPS(_bw,  468, 216, 104)) >> _s,       \
 115                 MCS_DURATION(_streams, _sgi,                            \
 116                              BW2VBPS(_bw,  702, 324, 156)) >> _s,       \
 117                 MCS_DURATION(_streams, _sgi,                            \
 118                              BW2VBPS(_bw,  936, 432, 208)) >> _s,       \
 119                 MCS_DURATION(_streams, _sgi,                            \
 120                              BW2VBPS(_bw, 1053, 486, 234)) >> _s,       \
 121                 MCS_DURATION(_streams, _sgi,                            \
 122                              BW2VBPS(_bw, 1170, 540, 260)) >> _s,       \
 123                 MCS_DURATION(_streams, _sgi,                            \
 124                              BW2VBPS(_bw, 1404, 648, 312)) >> _s,       \
 125                 MCS_DURATION(_streams, _sgi,                            \
 126                              BW2VBPS(_bw, 1560, 720, 346)) >> _s        \
 127         }                                                               \
 128 }
 129 
 130 #define VHT_GROUP_SHIFT(_streams, _sgi, _bw)                            \
 131         GROUP_SHIFT(MCS_DURATION(_streams, _sgi,                        \
 132                                  BW2VBPS(_bw,  117,  54,  26)))
 133 
 134 #define VHT_GROUP(_streams, _sgi, _bw)                                  \
 135         __VHT_GROUP(_streams, _sgi, _bw,                                \
 136                     VHT_GROUP_SHIFT(_streams, _sgi, _bw))
 137 
 138 #define CCK_DURATION(_bitrate, _short, _len)            \
 139         (1000 * (10 /* SIFS */ +                        \
 140          (_short ? 72 + 24 : 144 + 48) +                \
 141          (8 * (_len + 4) * 10) / (_bitrate)))
 142 
 143 #define CCK_ACK_DURATION(_bitrate, _short)                      \
 144         (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) +   \
 145          CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))
 146 
 147 #define CCK_DURATION_LIST(_short, _s)                   \
 148         CCK_ACK_DURATION(10, _short) >> _s,             \
 149         CCK_ACK_DURATION(20, _short) >> _s,             \
 150         CCK_ACK_DURATION(55, _short) >> _s,             \
 151         CCK_ACK_DURATION(110, _short) >> _s
 152 
 153 #define __CCK_GROUP(_s)                                 \
 154         [MINSTREL_CCK_GROUP] = {                        \
 155                 .streams = 1,                           \
 156                 .flags = 0,                             \
 157                 .shift = _s,                            \
 158                 .duration = {                           \
 159                         CCK_DURATION_LIST(false, _s),   \
 160                         CCK_DURATION_LIST(true, _s)     \
 161                 }                                       \
 162         }
 163 
 164 #define CCK_GROUP_SHIFT                                 \
 165         GROUP_SHIFT(CCK_ACK_DURATION(10, false))
 166 
 167 #define CCK_GROUP __CCK_GROUP(CCK_GROUP_SHIFT)
 168 
 169 
 170 static bool minstrel_vht_only = true;
 171 module_param(minstrel_vht_only, bool, 0644);
 172 MODULE_PARM_DESC(minstrel_vht_only,
 173                  "Use only VHT rates when VHT is supported by sta.");
 174 
 175 /*
 176  * To enable sufficiently targeted rate sampling, MCS rates are divided into
 177  * groups, based on the number of streams and flags (HT40, SGI) that they
 178  * use.
 179  *
 180  * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
 181  * BW -> SGI -> #streams
 182  */
 183 const struct mcs_group minstrel_mcs_groups[] = {
 184         MCS_GROUP(1, 0, BW_20),
 185         MCS_GROUP(2, 0, BW_20),
 186         MCS_GROUP(3, 0, BW_20),
 187         MCS_GROUP(4, 0, BW_20),
 188 
 189         MCS_GROUP(1, 1, BW_20),
 190         MCS_GROUP(2, 1, BW_20),
 191         MCS_GROUP(3, 1, BW_20),
 192         MCS_GROUP(4, 1, BW_20),
 193 
 194         MCS_GROUP(1, 0, BW_40),
 195         MCS_GROUP(2, 0, BW_40),
 196         MCS_GROUP(3, 0, BW_40),
 197         MCS_GROUP(4, 0, BW_40),
 198 
 199         MCS_GROUP(1, 1, BW_40),
 200         MCS_GROUP(2, 1, BW_40),
 201         MCS_GROUP(3, 1, BW_40),
 202         MCS_GROUP(4, 1, BW_40),
 203 
 204         CCK_GROUP,
 205 
 206         VHT_GROUP(1, 0, BW_20),
 207         VHT_GROUP(2, 0, BW_20),
 208         VHT_GROUP(3, 0, BW_20),
 209         VHT_GROUP(4, 0, BW_20),
 210 
 211         VHT_GROUP(1, 1, BW_20),
 212         VHT_GROUP(2, 1, BW_20),
 213         VHT_GROUP(3, 1, BW_20),
 214         VHT_GROUP(4, 1, BW_20),
 215 
 216         VHT_GROUP(1, 0, BW_40),
 217         VHT_GROUP(2, 0, BW_40),
 218         VHT_GROUP(3, 0, BW_40),
 219         VHT_GROUP(4, 0, BW_40),
 220 
 221         VHT_GROUP(1, 1, BW_40),
 222         VHT_GROUP(2, 1, BW_40),
 223         VHT_GROUP(3, 1, BW_40),
 224         VHT_GROUP(4, 1, BW_40),
 225 
 226         VHT_GROUP(1, 0, BW_80),
 227         VHT_GROUP(2, 0, BW_80),
 228         VHT_GROUP(3, 0, BW_80),
 229         VHT_GROUP(4, 0, BW_80),
 230 
 231         VHT_GROUP(1, 1, BW_80),
 232         VHT_GROUP(2, 1, BW_80),
 233         VHT_GROUP(3, 1, BW_80),
 234         VHT_GROUP(4, 1, BW_80),
 235 };
 236 
 237 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
 238 
 239 static void
 240 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
 241 
 242 /*
 243  * Some VHT MCSes are invalid (when Ndbps / Nes is not an integer)
 244  * e.g for MCS9@20MHzx1Nss: Ndbps=8x52*(5/6) Nes=1
 245  *
 246  * Returns the valid mcs map for struct minstrel_mcs_group_data.supported
 247  */
 248 static u16
 249 minstrel_get_valid_vht_rates(int bw, int nss, __le16 mcs_map)
 250 {
 251         u16 mask = 0;
 252 
 253         if (bw == BW_20) {
 254                 if (nss != 3 && nss != 6)
 255                         mask = BIT(9);
 256         } else if (bw == BW_80) {
 257                 if (nss == 3 || nss == 7)
 258                         mask = BIT(6);
 259                 else if (nss == 6)
 260                         mask = BIT(9);
 261         } else {
 262                 WARN_ON(bw != BW_40);
 263         }
 264 
 265         switch ((le16_to_cpu(mcs_map) >> (2 * (nss - 1))) & 3) {
 266         case IEEE80211_VHT_MCS_SUPPORT_0_7:
 267                 mask |= 0x300;
 268                 break;
 269         case IEEE80211_VHT_MCS_SUPPORT_0_8:
 270                 mask |= 0x200;
 271                 break;
 272         case IEEE80211_VHT_MCS_SUPPORT_0_9:
 273                 break;
 274         default:
 275                 mask = 0x3ff;
 276         }
 277 
 278         return 0x3ff & ~mask;
 279 }
 280 
 281 /*
 282  * Look up an MCS group index based on mac80211 rate information
 283  */
 284 static int
 285 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
 286 {
 287         return GROUP_IDX((rate->idx / 8) + 1,
 288                          !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
 289                          !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
 290 }
 291 
 292 static int
 293 minstrel_vht_get_group_idx(struct ieee80211_tx_rate *rate)
 294 {
 295         return VHT_GROUP_IDX(ieee80211_rate_get_vht_nss(rate),
 296                              !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
 297                              !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH) +
 298                              2*!!(rate->flags & IEEE80211_TX_RC_80_MHZ_WIDTH));
 299 }
 300 
 301 static struct minstrel_rate_stats *
 302 minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
 303                       struct ieee80211_tx_rate *rate)
 304 {
 305         int group, idx;
 306 
 307         if (rate->flags & IEEE80211_TX_RC_MCS) {
 308                 group = minstrel_ht_get_group_idx(rate);
 309                 idx = rate->idx % 8;
 310         } else if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
 311                 group = minstrel_vht_get_group_idx(rate);
 312                 idx = ieee80211_rate_get_vht_mcs(rate);
 313         } else {
 314                 group = MINSTREL_CCK_GROUP;
 315 
 316                 for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++)
 317                         if (rate->idx == mp->cck_rates[idx])
 318                                 break;
 319 
 320                 /* short preamble */
 321                 if ((mi->supported[group] & BIT(idx + 4)) &&
 322                     (rate->flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE))
 323                         idx += 4;
 324         }
 325         return &mi->groups[group].rates[idx];
 326 }
 327 
 328 static inline struct minstrel_rate_stats *
 329 minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
 330 {
 331         return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
 332 }
 333 
 334 static unsigned int
 335 minstrel_ht_avg_ampdu_len(struct minstrel_ht_sta *mi)
 336 {
 337         if (!mi->avg_ampdu_len)
 338                 return AVG_AMPDU_SIZE;
 339 
 340         return MINSTREL_TRUNC(mi->avg_ampdu_len);
 341 }
 342 
 343 /*
 344  * Return current throughput based on the average A-MPDU length, taking into
 345  * account the expected number of retransmissions and their expected length
 346  */
 347 int
 348 minstrel_ht_get_tp_avg(struct minstrel_ht_sta *mi, int group, int rate,
 349                        int prob_ewma)
 350 {
 351         unsigned int nsecs = 0;
 352 
 353         /* do not account throughput if sucess prob is below 10% */
 354         if (prob_ewma < MINSTREL_FRAC(10, 100))
 355                 return 0;
 356 
 357         if (group != MINSTREL_CCK_GROUP)
 358                 nsecs = 1000 * mi->overhead / minstrel_ht_avg_ampdu_len(mi);
 359 
 360         nsecs += minstrel_mcs_groups[group].duration[rate] <<
 361                  minstrel_mcs_groups[group].shift;
 362 
 363         /*
 364          * For the throughput calculation, limit the probability value to 90% to
 365          * account for collision related packet error rate fluctuation
 366          * (prob is scaled - see MINSTREL_FRAC above)
 367          */
 368         if (prob_ewma > MINSTREL_FRAC(90, 100))
 369                 return MINSTREL_TRUNC(100000 * ((MINSTREL_FRAC(90, 100) * 1000)
 370                                                                       / nsecs));
 371         else
 372                 return MINSTREL_TRUNC(100000 * ((prob_ewma * 1000) / nsecs));
 373 }
 374 
 375 /*
 376  * Find & sort topmost throughput rates
 377  *
 378  * If multiple rates provide equal throughput the sorting is based on their
 379  * current success probability. Higher success probability is preferred among
 380  * MCS groups, CCK rates do not provide aggregation and are therefore at last.
 381  */
 382 static void
 383 minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u16 index,
 384                                u16 *tp_list)
 385 {
 386         int cur_group, cur_idx, cur_tp_avg, cur_prob;
 387         int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
 388         int j = MAX_THR_RATES;
 389 
 390         cur_group = index / MCS_GROUP_RATES;
 391         cur_idx = index  % MCS_GROUP_RATES;
 392         cur_prob = mi->groups[cur_group].rates[cur_idx].prob_ewma;
 393         cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx, cur_prob);
 394 
 395         do {
 396                 tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
 397                 tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
 398                 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
 399                 tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx,
 400                                                     tmp_prob);
 401                 if (cur_tp_avg < tmp_tp_avg ||
 402                     (cur_tp_avg == tmp_tp_avg && cur_prob <= tmp_prob))
 403                         break;
 404                 j--;
 405         } while (j > 0);
 406 
 407         if (j < MAX_THR_RATES - 1) {
 408                 memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) *
 409                        (MAX_THR_RATES - (j + 1))));
 410         }
 411         if (j < MAX_THR_RATES)
 412                 tp_list[j] = index;
 413 }
 414 
 415 /*
 416  * Find and set the topmost probability rate per sta and per group
 417  */
 418 static void
 419 minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 index)
 420 {
 421         struct minstrel_mcs_group_data *mg;
 422         struct minstrel_rate_stats *mrs;
 423         int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
 424         int max_tp_group, cur_tp_avg, cur_group, cur_idx;
 425         int max_gpr_group, max_gpr_idx;
 426         int max_gpr_tp_avg, max_gpr_prob;
 427 
 428         cur_group = index / MCS_GROUP_RATES;
 429         cur_idx = index % MCS_GROUP_RATES;
 430         mg = &mi->groups[index / MCS_GROUP_RATES];
 431         mrs = &mg->rates[index % MCS_GROUP_RATES];
 432 
 433         tmp_group = mi->max_prob_rate / MCS_GROUP_RATES;
 434         tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES;
 435         tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
 436         tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
 437 
 438         /* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
 439          * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
 440         max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES;
 441         if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) &&
 442             (max_tp_group != MINSTREL_CCK_GROUP))
 443                 return;
 444 
 445         max_gpr_group = mg->max_group_prob_rate / MCS_GROUP_RATES;
 446         max_gpr_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
 447         max_gpr_prob = mi->groups[max_gpr_group].rates[max_gpr_idx].prob_ewma;
 448 
 449         if (mrs->prob_ewma > MINSTREL_FRAC(75, 100)) {
 450                 cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx,
 451                                                     mrs->prob_ewma);
 452                 if (cur_tp_avg > tmp_tp_avg)
 453                         mi->max_prob_rate = index;
 454 
 455                 max_gpr_tp_avg = minstrel_ht_get_tp_avg(mi, max_gpr_group,
 456                                                         max_gpr_idx,
 457                                                         max_gpr_prob);
 458                 if (cur_tp_avg > max_gpr_tp_avg)
 459                         mg->max_group_prob_rate = index;
 460         } else {
 461                 if (mrs->prob_ewma > tmp_prob)
 462                         mi->max_prob_rate = index;
 463                 if (mrs->prob_ewma > max_gpr_prob)
 464                         mg->max_group_prob_rate = index;
 465         }
 466 }
 467 
 468 
 469 /*
 470  * Assign new rate set per sta and use CCK rates only if the fastest
 471  * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted
 472  * rate sets where MCS and CCK rates are mixed, because CCK rates can
 473  * not use aggregation.
 474  */
 475 static void
 476 minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi,
 477                                  u16 tmp_mcs_tp_rate[MAX_THR_RATES],
 478                                  u16 tmp_cck_tp_rate[MAX_THR_RATES])
 479 {
 480         unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp, tmp_prob;
 481         int i;
 482 
 483         tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES;
 484         tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES;
 485         tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
 486         tmp_cck_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
 487 
 488         tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES;
 489         tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES;
 490         tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
 491         tmp_mcs_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
 492 
 493         if (tmp_cck_tp_rate && tmp_cck_tp > tmp_mcs_tp) {
 494                 for(i = 0; i < MAX_THR_RATES; i++) {
 495                         minstrel_ht_sort_best_tp_rates(mi, tmp_cck_tp_rate[i],
 496                                                        tmp_mcs_tp_rate);
 497                 }
 498         }
 499 
 500 }
 501 
 502 /*
 503  * Try to increase robustness of max_prob rate by decrease number of
 504  * streams if possible.
 505  */
 506 static inline void
 507 minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
 508 {
 509         struct minstrel_mcs_group_data *mg;
 510         int tmp_max_streams, group, tmp_idx, tmp_prob;
 511         int tmp_tp = 0;
 512 
 513         tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
 514                           MCS_GROUP_RATES].streams;
 515         for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
 516                 mg = &mi->groups[group];
 517                 if (!mi->supported[group] || group == MINSTREL_CCK_GROUP)
 518                         continue;
 519 
 520                 tmp_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
 521                 tmp_prob = mi->groups[group].rates[tmp_idx].prob_ewma;
 522 
 523                 if (tmp_tp < minstrel_ht_get_tp_avg(mi, group, tmp_idx, tmp_prob) &&
 524                    (minstrel_mcs_groups[group].streams < tmp_max_streams)) {
 525                                 mi->max_prob_rate = mg->max_group_prob_rate;
 526                                 tmp_tp = minstrel_ht_get_tp_avg(mi, group,
 527                                                                 tmp_idx,
 528                                                                 tmp_prob);
 529                 }
 530         }
 531 }
 532 
 533 static inline int
 534 minstrel_get_duration(int index)
 535 {
 536         const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
 537         unsigned int duration = group->duration[index % MCS_GROUP_RATES];
 538         return duration << group->shift;
 539 }
 540 
 541 static bool
 542 minstrel_ht_probe_group(struct minstrel_ht_sta *mi, const struct mcs_group *tp_group,
 543                                                 int tp_idx, const struct mcs_group *group)
 544 {
 545         if (group->bw < tp_group->bw)
 546                 return false;
 547 
 548         if (group->streams == tp_group->streams)
 549                 return true;
 550 
 551         if (tp_idx < 4 && group->streams == tp_group->streams - 1)
 552                 return true;
 553 
 554         return group->streams == tp_group->streams + 1;
 555 }
 556 
 557 static void
 558 minstrel_ht_find_probe_rates(struct minstrel_ht_sta *mi, u16 *rates, int *n_rates,
 559                              bool faster_rate)
 560 {
 561         const struct mcs_group *group, *tp_group;
 562         int i, g, max_dur;
 563         int tp_idx;
 564 
 565         tp_group = &minstrel_mcs_groups[mi->max_tp_rate[0] / MCS_GROUP_RATES];
 566         tp_idx = mi->max_tp_rate[0] % MCS_GROUP_RATES;
 567 
 568         max_dur = minstrel_get_duration(mi->max_tp_rate[0]);
 569         if (faster_rate)
 570                 max_dur -= max_dur / 16;
 571 
 572         for (g = 0; g < MINSTREL_GROUPS_NB; g++) {
 573                 u16 supported = mi->supported[g];
 574 
 575                 if (!supported)
 576                         continue;
 577 
 578                 group = &minstrel_mcs_groups[g];
 579                 if (!minstrel_ht_probe_group(mi, tp_group, tp_idx, group))
 580                         continue;
 581 
 582                 for (i = 0; supported; supported >>= 1, i++) {
 583                         int idx;
 584 
 585                         if (!(supported & 1))
 586                                 continue;
 587 
 588                         if ((group->duration[i] << group->shift) > max_dur)
 589                                 continue;
 590 
 591                         idx = g * MCS_GROUP_RATES + i;
 592                         if (idx == mi->max_tp_rate[0])
 593                                 continue;
 594 
 595                         rates[(*n_rates)++] = idx;
 596                         break;
 597                 }
 598         }
 599 }
 600 
 601 static void
 602 minstrel_ht_rate_sample_switch(struct minstrel_priv *mp,
 603                                struct minstrel_ht_sta *mi)
 604 {
 605         struct minstrel_rate_stats *mrs;
 606         u16 rates[MINSTREL_GROUPS_NB];
 607         int n_rates = 0;
 608         int probe_rate = 0;
 609         bool faster_rate;
 610         int i;
 611         u8 random;
 612 
 613         /*
 614          * Use rate switching instead of probing packets for devices with
 615          * little control over retry fallback behavior
 616          */
 617         if (mp->hw->max_rates > 1)
 618                 return;
 619 
 620         /*
 621          * If the current EWMA prob is >75%, look for a rate that's 6.25%
 622          * faster than the max tp rate.
 623          * If that fails, look again for a rate that is at least as fast
 624          */
 625         mrs = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
 626         faster_rate = mrs->prob_ewma > MINSTREL_FRAC(75, 100);
 627         minstrel_ht_find_probe_rates(mi, rates, &n_rates, faster_rate);
 628         if (!n_rates && faster_rate)
 629                 minstrel_ht_find_probe_rates(mi, rates, &n_rates, false);
 630 
 631         /* If no suitable rate was found, try to pick the next one in the group */
 632         if (!n_rates) {
 633                 int g_idx = mi->max_tp_rate[0] / MCS_GROUP_RATES;
 634                 u16 supported = mi->supported[g_idx];
 635 
 636                 supported >>= mi->max_tp_rate[0] % MCS_GROUP_RATES;
 637                 for (i = 0; supported; supported >>= 1, i++) {
 638                         if (!(supported & 1))
 639                                 continue;
 640 
 641                         probe_rate = mi->max_tp_rate[0] + i;
 642                         goto out;
 643                 }
 644 
 645                 return;
 646         }
 647 
 648         i = 0;
 649         if (n_rates > 1) {
 650                 random = prandom_u32();
 651                 i = random % n_rates;
 652         }
 653         probe_rate = rates[i];
 654 
 655 out:
 656         mi->sample_rate = probe_rate;
 657         mi->sample_mode = MINSTREL_SAMPLE_ACTIVE;
 658 }
 659 
 660 /*
 661  * Update rate statistics and select new primary rates
 662  *
 663  * Rules for rate selection:
 664  *  - max_prob_rate must use only one stream, as a tradeoff between delivery
 665  *    probability and throughput during strong fluctuations
 666  *  - as long as the max prob rate has a probability of more than 75%, pick
 667  *    higher throughput rates, even if the probablity is a bit lower
 668  */
 669 static void
 670 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
 671                          bool sample)
 672 {
 673         struct minstrel_mcs_group_data *mg;
 674         struct minstrel_rate_stats *mrs;
 675         int group, i, j, cur_prob;
 676         u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
 677         u16 tmp_cck_tp_rate[MAX_THR_RATES], index;
 678 
 679         mi->sample_mode = MINSTREL_SAMPLE_IDLE;
 680 
 681         if (sample) {
 682                 mi->total_packets_cur = mi->total_packets -
 683                                         mi->total_packets_last;
 684                 mi->total_packets_last = mi->total_packets;
 685         }
 686         if (!mp->sample_switch)
 687                 sample = false;
 688         if (mi->total_packets_cur < SAMPLE_SWITCH_THR && mp->sample_switch != 1)
 689             sample = false;
 690 
 691         if (mi->ampdu_packets > 0) {
 692                 if (!ieee80211_hw_check(mp->hw, TX_STATUS_NO_AMPDU_LEN))
 693                         mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
 694                                 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets),
 695                                               EWMA_LEVEL);
 696                 else
 697                         mi->avg_ampdu_len = 0;
 698                 mi->ampdu_len = 0;
 699                 mi->ampdu_packets = 0;
 700         }
 701 
 702         mi->sample_slow = 0;
 703         mi->sample_count = 0;
 704 
 705         memset(tmp_mcs_tp_rate, 0, sizeof(tmp_mcs_tp_rate));
 706         memset(tmp_cck_tp_rate, 0, sizeof(tmp_cck_tp_rate));
 707         if (mi->supported[MINSTREL_CCK_GROUP])
 708                 for (j = 0; j < ARRAY_SIZE(tmp_cck_tp_rate); j++)
 709                         tmp_cck_tp_rate[j] = MINSTREL_CCK_GROUP * MCS_GROUP_RATES;
 710 
 711         if (mi->supported[MINSTREL_VHT_GROUP_0])
 712                 index = MINSTREL_VHT_GROUP_0 * MCS_GROUP_RATES;
 713         else
 714                 index = MINSTREL_HT_GROUP_0 * MCS_GROUP_RATES;
 715 
 716         for (j = 0; j < ARRAY_SIZE(tmp_mcs_tp_rate); j++)
 717                 tmp_mcs_tp_rate[j] = index;
 718 
 719         /* Find best rate sets within all MCS groups*/
 720         for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
 721 
 722                 mg = &mi->groups[group];
 723                 if (!mi->supported[group])
 724                         continue;
 725 
 726                 mi->sample_count++;
 727 
 728                 /* (re)Initialize group rate indexes */
 729                 for(j = 0; j < MAX_THR_RATES; j++)
 730                         tmp_group_tp_rate[j] = MCS_GROUP_RATES * group;
 731 
 732                 for (i = 0; i < MCS_GROUP_RATES; i++) {
 733                         if (!(mi->supported[group] & BIT(i)))
 734                                 continue;
 735 
 736                         index = MCS_GROUP_RATES * group + i;
 737 
 738                         mrs = &mg->rates[i];
 739                         mrs->retry_updated = false;
 740                         minstrel_calc_rate_stats(mrs);
 741                         cur_prob = mrs->prob_ewma;
 742 
 743                         if (minstrel_ht_get_tp_avg(mi, group, i, cur_prob) == 0)
 744                                 continue;
 745 
 746                         /* Find max throughput rate set */
 747                         if (group != MINSTREL_CCK_GROUP) {
 748                                 minstrel_ht_sort_best_tp_rates(mi, index,
 749                                                                tmp_mcs_tp_rate);
 750                         } else if (group == MINSTREL_CCK_GROUP) {
 751                                 minstrel_ht_sort_best_tp_rates(mi, index,
 752                                                                tmp_cck_tp_rate);
 753                         }
 754 
 755                         /* Find max throughput rate set within a group */
 756                         minstrel_ht_sort_best_tp_rates(mi, index,
 757                                                        tmp_group_tp_rate);
 758 
 759                         /* Find max probability rate per group and global */
 760                         minstrel_ht_set_best_prob_rate(mi, index);
 761                 }
 762 
 763                 memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
 764                        sizeof(mg->max_group_tp_rate));
 765         }
 766 
 767         /* Assign new rate set per sta */
 768         minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate);
 769         memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));
 770 
 771         /* Try to increase robustness of max_prob_rate*/
 772         minstrel_ht_prob_rate_reduce_streams(mi);
 773 
 774         /* try to sample all available rates during each interval */
 775         mi->sample_count *= 8;
 776 
 777         if (sample)
 778                 minstrel_ht_rate_sample_switch(mp, mi);
 779 
 780 #ifdef CONFIG_MAC80211_DEBUGFS
 781         /* use fixed index if set */
 782         if (mp->fixed_rate_idx != -1) {
 783                 for (i = 0; i < 4; i++)
 784                         mi->max_tp_rate[i] = mp->fixed_rate_idx;
 785                 mi->max_prob_rate = mp->fixed_rate_idx;
 786                 mi->sample_mode = MINSTREL_SAMPLE_IDLE;
 787         }
 788 #endif
 789 
 790         /* Reset update timer */
 791         mi->last_stats_update = jiffies;
 792 }
 793 
 794 static bool
 795 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
 796 {
 797         if (rate->idx < 0)
 798                 return false;
 799 
 800         if (!rate->count)
 801                 return false;
 802 
 803         if (rate->flags & IEEE80211_TX_RC_MCS ||
 804             rate->flags & IEEE80211_TX_RC_VHT_MCS)
 805                 return true;
 806 
 807         return rate->idx == mp->cck_rates[0] ||
 808                rate->idx == mp->cck_rates[1] ||
 809                rate->idx == mp->cck_rates[2] ||
 810                rate->idx == mp->cck_rates[3];
 811 }
 812 
 813 static void
 814 minstrel_set_next_sample_idx(struct minstrel_ht_sta *mi)
 815 {
 816         struct minstrel_mcs_group_data *mg;
 817 
 818         for (;;) {
 819                 mi->sample_group++;
 820                 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
 821                 mg = &mi->groups[mi->sample_group];
 822 
 823                 if (!mi->supported[mi->sample_group])
 824                         continue;
 825 
 826                 if (++mg->index >= MCS_GROUP_RATES) {
 827                         mg->index = 0;
 828                         if (++mg->column >= ARRAY_SIZE(sample_table))
 829                                 mg->column = 0;
 830                 }
 831                 break;
 832         }
 833 }
 834 
 835 static void
 836 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u16 *idx, bool primary)
 837 {
 838         int group, orig_group;
 839 
 840         orig_group = group = *idx / MCS_GROUP_RATES;
 841         while (group > 0) {
 842                 group--;
 843 
 844                 if (!mi->supported[group])
 845                         continue;
 846 
 847                 if (minstrel_mcs_groups[group].streams >
 848                     minstrel_mcs_groups[orig_group].streams)
 849                         continue;
 850 
 851                 if (primary)
 852                         *idx = mi->groups[group].max_group_tp_rate[0];
 853                 else
 854                         *idx = mi->groups[group].max_group_tp_rate[1];
 855                 break;
 856         }
 857 }
 858 
 859 static void
 860 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
 861 {
 862         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 863         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 864         u16 tid;
 865 
 866         if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
 867                 return;
 868 
 869         if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
 870                 return;
 871 
 872         if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
 873                 return;
 874 
 875         tid = ieee80211_get_tid(hdr);
 876         if (likely(sta->ampdu_mlme.tid_tx[tid]))
 877                 return;
 878 
 879         ieee80211_start_tx_ba_session(pubsta, tid, 0);
 880 }
 881 
 882 static void
 883 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
 884                       void *priv_sta, struct ieee80211_tx_status *st)
 885 {
 886         struct ieee80211_tx_info *info = st->info;
 887         struct minstrel_ht_sta_priv *msp = priv_sta;
 888         struct minstrel_ht_sta *mi = &msp->ht;
 889         struct ieee80211_tx_rate *ar = info->status.rates;
 890         struct minstrel_rate_stats *rate, *rate2, *rate_sample = NULL;
 891         struct minstrel_priv *mp = priv;
 892         bool last, update = false;
 893         bool sample_status = false;
 894         int i;
 895 
 896         if (!msp->is_ht)
 897                 return mac80211_minstrel.tx_status_ext(priv, sband,
 898                                                        &msp->legacy, st);
 899 
 900 
 901         /* This packet was aggregated but doesn't carry status info */
 902         if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
 903             !(info->flags & IEEE80211_TX_STAT_AMPDU))
 904                 return;
 905 
 906         if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
 907                 info->status.ampdu_ack_len =
 908                         (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
 909                 info->status.ampdu_len = 1;
 910         }
 911 
 912         mi->ampdu_packets++;
 913         mi->ampdu_len += info->status.ampdu_len;
 914 
 915         if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
 916                 int avg_ampdu_len = minstrel_ht_avg_ampdu_len(mi);
 917 
 918                 mi->sample_wait = 16 + 2 * avg_ampdu_len;
 919                 mi->sample_tries = 1;
 920                 mi->sample_count--;
 921         }
 922 
 923         if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
 924                 mi->sample_packets += info->status.ampdu_len;
 925 
 926         if (mi->sample_mode != MINSTREL_SAMPLE_IDLE)
 927                 rate_sample = minstrel_get_ratestats(mi, mi->sample_rate);
 928 
 929         last = !minstrel_ht_txstat_valid(mp, &ar[0]);
 930         for (i = 0; !last; i++) {
 931                 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
 932                        !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
 933 
 934                 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
 935                 if (rate == rate_sample)
 936                         sample_status = true;
 937 
 938                 if (last)
 939                         rate->success += info->status.ampdu_ack_len;
 940 
 941                 rate->attempts += ar[i].count * info->status.ampdu_len;
 942         }
 943 
 944         switch (mi->sample_mode) {
 945         case MINSTREL_SAMPLE_IDLE:
 946                 break;
 947 
 948         case MINSTREL_SAMPLE_ACTIVE:
 949                 if (!sample_status)
 950                         break;
 951 
 952                 mi->sample_mode = MINSTREL_SAMPLE_PENDING;
 953                 update = true;
 954                 break;
 955 
 956         case MINSTREL_SAMPLE_PENDING:
 957                 if (sample_status)
 958                         break;
 959 
 960                 update = true;
 961                 minstrel_ht_update_stats(mp, mi, false);
 962                 break;
 963         }
 964 
 965 
 966         if (mp->hw->max_rates > 1) {
 967                 /*
 968                  * check for sudden death of spatial multiplexing,
 969                  * downgrade to a lower number of streams if necessary.
 970                  */
 971                 rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
 972                 if (rate->attempts > 30 &&
 973                     MINSTREL_FRAC(rate->success, rate->attempts) <
 974                     MINSTREL_FRAC(20, 100)) {
 975                         minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
 976                         update = true;
 977                 }
 978 
 979                 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
 980                 if (rate2->attempts > 30 &&
 981                     MINSTREL_FRAC(rate2->success, rate2->attempts) <
 982                     MINSTREL_FRAC(20, 100)) {
 983                         minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
 984                         update = true;
 985                 }
 986         }
 987 
 988         if (time_after(jiffies, mi->last_stats_update +
 989                                 (mp->update_interval / 2 * HZ) / 1000)) {
 990                 update = true;
 991                 minstrel_ht_update_stats(mp, mi, true);
 992         }
 993 
 994         if (update)
 995                 minstrel_ht_update_rates(mp, mi);
 996 }
 997 
 998 static void
 999 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1000                          int index)
1001 {
1002         struct minstrel_rate_stats *mrs;
1003         unsigned int tx_time, tx_time_rtscts, tx_time_data;
1004         unsigned int cw = mp->cw_min;
1005         unsigned int ctime = 0;
1006         unsigned int t_slot = 9; /* FIXME */
1007         unsigned int ampdu_len = minstrel_ht_avg_ampdu_len(mi);
1008         unsigned int overhead = 0, overhead_rtscts = 0;
1009 
1010         mrs = minstrel_get_ratestats(mi, index);
1011         if (mrs->prob_ewma < MINSTREL_FRAC(1, 10)) {
1012                 mrs->retry_count = 1;
1013                 mrs->retry_count_rtscts = 1;
1014                 return;
1015         }
1016 
1017         mrs->retry_count = 2;
1018         mrs->retry_count_rtscts = 2;
1019         mrs->retry_updated = true;
1020 
1021         tx_time_data = minstrel_get_duration(index) * ampdu_len / 1000;
1022 
1023         /* Contention time for first 2 tries */
1024         ctime = (t_slot * cw) >> 1;
1025         cw = min((cw << 1) | 1, mp->cw_max);
1026         ctime += (t_slot * cw) >> 1;
1027         cw = min((cw << 1) | 1, mp->cw_max);
1028 
1029         if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
1030                 overhead = mi->overhead;
1031                 overhead_rtscts = mi->overhead_rtscts;
1032         }
1033 
1034         /* Total TX time for data and Contention after first 2 tries */
1035         tx_time = ctime + 2 * (overhead + tx_time_data);
1036         tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
1037 
1038         /* See how many more tries we can fit inside segment size */
1039         do {
1040                 /* Contention time for this try */
1041                 ctime = (t_slot * cw) >> 1;
1042                 cw = min((cw << 1) | 1, mp->cw_max);
1043 
1044                 /* Total TX time after this try */
1045                 tx_time += ctime + overhead + tx_time_data;
1046                 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
1047 
1048                 if (tx_time_rtscts < mp->segment_size)
1049                         mrs->retry_count_rtscts++;
1050         } while ((tx_time < mp->segment_size) &&
1051                  (++mrs->retry_count < mp->max_retry));
1052 }
1053 
1054 
1055 static void
1056 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1057                      struct ieee80211_sta_rates *ratetbl, int offset, int index)
1058 {
1059         const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
1060         struct minstrel_rate_stats *mrs;
1061         u8 idx;
1062         u16 flags = group->flags;
1063 
1064         mrs = minstrel_get_ratestats(mi, index);
1065         if (!mrs->retry_updated)
1066                 minstrel_calc_retransmit(mp, mi, index);
1067 
1068         if (mrs->prob_ewma < MINSTREL_FRAC(20, 100) || !mrs->retry_count) {
1069                 ratetbl->rate[offset].count = 2;
1070                 ratetbl->rate[offset].count_rts = 2;
1071                 ratetbl->rate[offset].count_cts = 2;
1072         } else {
1073                 ratetbl->rate[offset].count = mrs->retry_count;
1074                 ratetbl->rate[offset].count_cts = mrs->retry_count;
1075                 ratetbl->rate[offset].count_rts = mrs->retry_count_rtscts;
1076         }
1077 
1078         if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP)
1079                 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
1080         else if (flags & IEEE80211_TX_RC_VHT_MCS)
1081                 idx = ((group->streams - 1) << 4) |
1082                       ((index % MCS_GROUP_RATES) & 0xF);
1083         else
1084                 idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;
1085 
1086         /* enable RTS/CTS if needed:
1087          *  - if station is in dynamic SMPS (and streams > 1)
1088          *  - for fallback rates, to increase chances of getting through
1089          */
1090         if (offset > 0 ||
1091             (mi->sta->smps_mode == IEEE80211_SMPS_DYNAMIC &&
1092              group->streams > 1)) {
1093                 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
1094                 flags |= IEEE80211_TX_RC_USE_RTS_CTS;
1095         }
1096 
1097         ratetbl->rate[offset].idx = idx;
1098         ratetbl->rate[offset].flags = flags;
1099 }
1100 
1101 static inline int
1102 minstrel_ht_get_prob_ewma(struct minstrel_ht_sta *mi, int rate)
1103 {
1104         int group = rate / MCS_GROUP_RATES;
1105         rate %= MCS_GROUP_RATES;
1106         return mi->groups[group].rates[rate].prob_ewma;
1107 }
1108 
1109 static int
1110 minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta *mi)
1111 {
1112         int group = mi->max_prob_rate / MCS_GROUP_RATES;
1113         const struct mcs_group *g = &minstrel_mcs_groups[group];
1114         int rate = mi->max_prob_rate % MCS_GROUP_RATES;
1115         unsigned int duration;
1116 
1117         /* Disable A-MSDU if max_prob_rate is bad */
1118         if (mi->groups[group].rates[rate].prob_ewma < MINSTREL_FRAC(50, 100))
1119                 return 1;
1120 
1121         duration = g->duration[rate];
1122         duration <<= g->shift;
1123 
1124         /* If the rate is slower than single-stream MCS1, make A-MSDU limit small */
1125         if (duration > MCS_DURATION(1, 0, 52))
1126                 return 500;
1127 
1128         /*
1129          * If the rate is slower than single-stream MCS4, limit A-MSDU to usual
1130          * data packet size
1131          */
1132         if (duration > MCS_DURATION(1, 0, 104))
1133                 return 1600;
1134 
1135         /*
1136          * If the rate is slower than single-stream MCS7, or if the max throughput
1137          * rate success probability is less than 75%, limit A-MSDU to twice the usual
1138          * data packet size
1139          */
1140         if (duration > MCS_DURATION(1, 0, 260) ||
1141             (minstrel_ht_get_prob_ewma(mi, mi->max_tp_rate[0]) <
1142              MINSTREL_FRAC(75, 100)))
1143                 return 3200;
1144 
1145         /*
1146          * HT A-MPDU limits maximum MPDU size under BA agreement to 4095 bytes.
1147          * Since aggregation sessions are started/stopped without txq flush, use
1148          * the limit here to avoid the complexity of having to de-aggregate
1149          * packets in the queue.
1150          */
1151         if (!mi->sta->vht_cap.vht_supported)
1152                 return IEEE80211_MAX_MPDU_LEN_HT_BA;
1153 
1154         /* unlimited */
1155         return 0;
1156 }
1157 
1158 static void
1159 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
1160 {
1161         struct ieee80211_sta_rates *rates;
1162         u16 first_rate = mi->max_tp_rate[0];
1163         int i = 0;
1164 
1165         if (mi->sample_mode == MINSTREL_SAMPLE_ACTIVE)
1166                 first_rate = mi->sample_rate;
1167 
1168         rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
1169         if (!rates)
1170                 return;
1171 
1172         /* Start with max_tp_rate[0] */
1173         minstrel_ht_set_rate(mp, mi, rates, i++, first_rate);
1174 
1175         if (mp->hw->max_rates >= 3) {
1176                 /* At least 3 tx rates supported, use max_tp_rate[1] next */
1177                 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]);
1178         }
1179 
1180         if (mp->hw->max_rates >= 2) {
1181                 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
1182         }
1183 
1184         mi->sta->max_rc_amsdu_len = minstrel_ht_get_max_amsdu_len(mi);
1185         rates->rate[i].idx = -1;
1186         rate_control_set_rates(mp->hw, mi->sta, rates);
1187 }
1188 
1189 static int
1190 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
1191 {
1192         struct minstrel_rate_stats *mrs;
1193         struct minstrel_mcs_group_data *mg;
1194         unsigned int sample_dur, sample_group, cur_max_tp_streams;
1195         int tp_rate1, tp_rate2;
1196         int sample_idx = 0;
1197 
1198         if (mp->hw->max_rates == 1 && mp->sample_switch &&
1199             (mi->total_packets_cur >= SAMPLE_SWITCH_THR ||
1200              mp->sample_switch == 1))
1201                 return -1;
1202 
1203         if (mi->sample_wait > 0) {
1204                 mi->sample_wait--;
1205                 return -1;
1206         }
1207 
1208         if (!mi->sample_tries)
1209                 return -1;
1210 
1211         sample_group = mi->sample_group;
1212         mg = &mi->groups[sample_group];
1213         sample_idx = sample_table[mg->column][mg->index];
1214         minstrel_set_next_sample_idx(mi);
1215 
1216         if (!(mi->supported[sample_group] & BIT(sample_idx)))
1217                 return -1;
1218 
1219         mrs = &mg->rates[sample_idx];
1220         sample_idx += sample_group * MCS_GROUP_RATES;
1221 
1222         /* Set tp_rate1, tp_rate2 to the highest / second highest max_tp_rate */
1223         if (minstrel_get_duration(mi->max_tp_rate[0]) >
1224             minstrel_get_duration(mi->max_tp_rate[1])) {
1225                 tp_rate1 = mi->max_tp_rate[1];
1226                 tp_rate2 = mi->max_tp_rate[0];
1227         } else {
1228                 tp_rate1 = mi->max_tp_rate[0];
1229                 tp_rate2 = mi->max_tp_rate[1];
1230         }
1231 
1232         /*
1233          * Sampling might add some overhead (RTS, no aggregation)
1234          * to the frame. Hence, don't use sampling for the highest currently
1235          * used highest throughput or probability rate.
1236          */
1237         if (sample_idx == mi->max_tp_rate[0] || sample_idx == mi->max_prob_rate)
1238                 return -1;
1239 
1240         /*
1241          * Do not sample if the probability is already higher than 95%,
1242          * or if the rate is 3 times slower than the current max probability
1243          * rate, to avoid wasting airtime.
1244          */
1245         sample_dur = minstrel_get_duration(sample_idx);
1246         if (mrs->prob_ewma > MINSTREL_FRAC(95, 100) ||
1247             minstrel_get_duration(mi->max_prob_rate) * 3 < sample_dur)
1248                 return -1;
1249 
1250 
1251         /*
1252          * For devices with no configurable multi-rate retry, skip sampling
1253          * below the per-group max throughput rate, and only use one sampling
1254          * attempt per rate
1255          */
1256         if (mp->hw->max_rates == 1 &&
1257             (minstrel_get_duration(mg->max_group_tp_rate[0]) < sample_dur ||
1258              mrs->attempts))
1259                 return -1;
1260 
1261         /* Skip already sampled slow rates */
1262         if (sample_dur >= minstrel_get_duration(tp_rate1) && mrs->attempts)
1263                 return -1;
1264 
1265         /*
1266          * Make sure that lower rates get sampled only occasionally,
1267          * if the link is working perfectly.
1268          */
1269 
1270         cur_max_tp_streams = minstrel_mcs_groups[tp_rate1 /
1271                 MCS_GROUP_RATES].streams;
1272         if (sample_dur >= minstrel_get_duration(tp_rate2) &&
1273             (cur_max_tp_streams - 1 <
1274              minstrel_mcs_groups[sample_group].streams ||
1275              sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
1276                 if (mrs->sample_skipped < 20)
1277                         return -1;
1278 
1279                 if (mi->sample_slow++ > 2)
1280                         return -1;
1281         }
1282         mi->sample_tries--;
1283 
1284         return sample_idx;
1285 }
1286 
1287 static void
1288 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
1289                      struct ieee80211_tx_rate_control *txrc)
1290 {
1291         const struct mcs_group *sample_group;
1292         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
1293         struct ieee80211_tx_rate *rate = &info->status.rates[0];
1294         struct minstrel_ht_sta_priv *msp = priv_sta;
1295         struct minstrel_ht_sta *mi = &msp->ht;
1296         struct minstrel_priv *mp = priv;
1297         int sample_idx;
1298 
1299         if (!msp->is_ht)
1300                 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
1301 
1302         if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
1303             mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
1304                 minstrel_aggr_check(sta, txrc->skb);
1305 
1306         info->flags |= mi->tx_flags;
1307 
1308 #ifdef CONFIG_MAC80211_DEBUGFS
1309         if (mp->fixed_rate_idx != -1)
1310                 return;
1311 #endif
1312 
1313         /* Don't use EAPOL frames for sampling on non-mrr hw */
1314         if (mp->hw->max_rates == 1 &&
1315             (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
1316                 sample_idx = -1;
1317         else
1318                 sample_idx = minstrel_get_sample_rate(mp, mi);
1319 
1320         mi->total_packets++;
1321 
1322         /* wraparound */
1323         if (mi->total_packets == ~0) {
1324                 mi->total_packets = 0;
1325                 mi->sample_packets = 0;
1326         }
1327 
1328         if (sample_idx < 0)
1329                 return;
1330 
1331         sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
1332         sample_idx %= MCS_GROUP_RATES;
1333 
1334         if (sample_group == &minstrel_mcs_groups[MINSTREL_CCK_GROUP] &&
1335             (sample_idx >= 4) != txrc->short_preamble)
1336                 return;
1337 
1338         info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
1339         rate->count = 1;
1340 
1341         if (sample_group == &minstrel_mcs_groups[MINSTREL_CCK_GROUP]) {
1342                 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
1343                 rate->idx = mp->cck_rates[idx];
1344         } else if (sample_group->flags & IEEE80211_TX_RC_VHT_MCS) {
1345                 ieee80211_rate_set_vht(rate, sample_idx % MCS_GROUP_RATES,
1346                                        sample_group->streams);
1347         } else {
1348                 rate->idx = sample_idx + (sample_group->streams - 1) * 8;
1349         }
1350 
1351         rate->flags = sample_group->flags;
1352 }
1353 
1354 static void
1355 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1356                        struct ieee80211_supported_band *sband,
1357                        struct ieee80211_sta *sta)
1358 {
1359         int i;
1360 
1361         if (sband->band != NL80211_BAND_2GHZ)
1362                 return;
1363 
1364         if (!ieee80211_hw_check(mp->hw, SUPPORTS_HT_CCK_RATES))
1365                 return;
1366 
1367         mi->cck_supported = 0;
1368         mi->cck_supported_short = 0;
1369         for (i = 0; i < 4; i++) {
1370                 if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
1371                         continue;
1372 
1373                 mi->cck_supported |= BIT(i);
1374                 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
1375                         mi->cck_supported_short |= BIT(i);
1376         }
1377 
1378         mi->supported[MINSTREL_CCK_GROUP] = mi->cck_supported;
1379 }
1380 
1381 static void
1382 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
1383                         struct cfg80211_chan_def *chandef,
1384                         struct ieee80211_sta *sta, void *priv_sta)
1385 {
1386         struct minstrel_priv *mp = priv;
1387         struct minstrel_ht_sta_priv *msp = priv_sta;
1388         struct minstrel_ht_sta *mi = &msp->ht;
1389         struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
1390         u16 ht_cap = sta->ht_cap.cap;
1391         struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap;
1392         int use_vht;
1393         int n_supported = 0;
1394         int ack_dur;
1395         int stbc;
1396         int i;
1397         bool ldpc;
1398 
1399         /* fall back to the old minstrel for legacy stations */
1400         if (!sta->ht_cap.ht_supported)
1401                 goto use_legacy;
1402 
1403         BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != MINSTREL_GROUPS_NB);
1404 
1405         if (vht_cap->vht_supported)
1406                 use_vht = vht_cap->vht_mcs.tx_mcs_map != cpu_to_le16(~0);
1407         else
1408                 use_vht = 0;
1409 
1410         msp->is_ht = true;
1411         memset(mi, 0, sizeof(*mi));
1412 
1413         mi->sta = sta;
1414         mi->last_stats_update = jiffies;
1415 
1416         ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
1417         mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
1418         mi->overhead += ack_dur;
1419         mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
1420 
1421         mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
1422 
1423         /* When using MRR, sample more on the first attempt, without delay */
1424         if (mp->has_mrr) {
1425                 mi->sample_count = 16;
1426                 mi->sample_wait = 0;
1427         } else {
1428                 mi->sample_count = 8;
1429                 mi->sample_wait = 8;
1430         }
1431         mi->sample_tries = 4;
1432 
1433         if (!use_vht) {
1434                 stbc = (ht_cap & IEEE80211_HT_CAP_RX_STBC) >>
1435                         IEEE80211_HT_CAP_RX_STBC_SHIFT;
1436 
1437                 ldpc = ht_cap & IEEE80211_HT_CAP_LDPC_CODING;
1438         } else {
1439                 stbc = (vht_cap->cap & IEEE80211_VHT_CAP_RXSTBC_MASK) >>
1440                         IEEE80211_VHT_CAP_RXSTBC_SHIFT;
1441 
1442                 ldpc = vht_cap->cap & IEEE80211_VHT_CAP_RXLDPC;
1443         }
1444 
1445         mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
1446         if (ldpc)
1447                 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
1448 
1449         for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
1450                 u32 gflags = minstrel_mcs_groups[i].flags;
1451                 int bw, nss;
1452 
1453                 mi->supported[i] = 0;
1454                 if (i == MINSTREL_CCK_GROUP) {
1455                         minstrel_ht_update_cck(mp, mi, sband, sta);
1456                         continue;
1457                 }
1458 
1459                 if (gflags & IEEE80211_TX_RC_SHORT_GI) {
1460                         if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
1461                                 if (!(ht_cap & IEEE80211_HT_CAP_SGI_40))
1462                                         continue;
1463                         } else {
1464                                 if (!(ht_cap & IEEE80211_HT_CAP_SGI_20))
1465                                         continue;
1466                         }
1467                 }
1468 
1469                 if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
1470                     sta->bandwidth < IEEE80211_STA_RX_BW_40)
1471                         continue;
1472 
1473                 nss = minstrel_mcs_groups[i].streams;
1474 
1475                 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
1476                 if (sta->smps_mode == IEEE80211_SMPS_STATIC && nss > 1)
1477                         continue;
1478 
1479                 /* HT rate */
1480                 if (gflags & IEEE80211_TX_RC_MCS) {
1481                         if (use_vht && minstrel_vht_only)
1482                                 continue;
1483 
1484                         mi->supported[i] = mcs->rx_mask[nss - 1];
1485                         if (mi->supported[i])
1486                                 n_supported++;
1487                         continue;
1488                 }
1489 
1490                 /* VHT rate */
1491                 if (!vht_cap->vht_supported ||
1492                     WARN_ON(!(gflags & IEEE80211_TX_RC_VHT_MCS)) ||
1493                     WARN_ON(gflags & IEEE80211_TX_RC_160_MHZ_WIDTH))
1494                         continue;
1495 
1496                 if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH) {
1497                         if (sta->bandwidth < IEEE80211_STA_RX_BW_80 ||
1498                             ((gflags & IEEE80211_TX_RC_SHORT_GI) &&
1499                              !(vht_cap->cap & IEEE80211_VHT_CAP_SHORT_GI_80))) {
1500                                 continue;
1501                         }
1502                 }
1503 
1504                 if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH)
1505                         bw = BW_40;
1506                 else if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH)
1507                         bw = BW_80;
1508                 else
1509                         bw = BW_20;
1510 
1511                 mi->supported[i] = minstrel_get_valid_vht_rates(bw, nss,
1512                                 vht_cap->vht_mcs.tx_mcs_map);
1513 
1514                 if (mi->supported[i])
1515                         n_supported++;
1516         }
1517 
1518         if (!n_supported)
1519                 goto use_legacy;
1520 
1521         mi->supported[MINSTREL_CCK_GROUP] |= mi->cck_supported_short << 4;
1522 
1523         /* create an initial rate table with the lowest supported rates */
1524         minstrel_ht_update_stats(mp, mi, true);
1525         minstrel_ht_update_rates(mp, mi);
1526 
1527         return;
1528 
1529 use_legacy:
1530         msp->is_ht = false;
1531         memset(&msp->legacy, 0, sizeof(msp->legacy));
1532         msp->legacy.r = msp->ratelist;
1533         msp->legacy.sample_table = msp->sample_table;
1534         return mac80211_minstrel.rate_init(priv, sband, chandef, sta,
1535                                            &msp->legacy);
1536 }
1537 
1538 static void
1539 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
1540                       struct cfg80211_chan_def *chandef,
1541                       struct ieee80211_sta *sta, void *priv_sta)
1542 {
1543         minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1544 }
1545 
1546 static void
1547 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
1548                         struct cfg80211_chan_def *chandef,
1549                         struct ieee80211_sta *sta, void *priv_sta,
1550                         u32 changed)
1551 {
1552         minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1553 }
1554 
1555 static void *
1556 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
1557 {
1558         struct ieee80211_supported_band *sband;
1559         struct minstrel_ht_sta_priv *msp;
1560         struct minstrel_priv *mp = priv;
1561         struct ieee80211_hw *hw = mp->hw;
1562         int max_rates = 0;
1563         int i;
1564 
1565         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1566                 sband = hw->wiphy->bands[i];
1567                 if (sband && sband->n_bitrates > max_rates)
1568                         max_rates = sband->n_bitrates;
1569         }
1570 
1571         msp = kzalloc(sizeof(*msp), gfp);
1572         if (!msp)
1573                 return NULL;
1574 
1575         msp->ratelist = kcalloc(max_rates, sizeof(struct minstrel_rate), gfp);
1576         if (!msp->ratelist)
1577                 goto error;
1578 
1579         msp->sample_table = kmalloc_array(max_rates, SAMPLE_COLUMNS, gfp);
1580         if (!msp->sample_table)
1581                 goto error1;
1582 
1583         return msp;
1584 
1585 error1:
1586         kfree(msp->ratelist);
1587 error:
1588         kfree(msp);
1589         return NULL;
1590 }
1591 
1592 static void
1593 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1594 {
1595         struct minstrel_ht_sta_priv *msp = priv_sta;
1596 
1597         kfree(msp->sample_table);
1598         kfree(msp->ratelist);
1599         kfree(msp);
1600 }
1601 
1602 static void
1603 minstrel_ht_init_cck_rates(struct minstrel_priv *mp)
1604 {
1605         static const int bitrates[4] = { 10, 20, 55, 110 };
1606         struct ieee80211_supported_band *sband;
1607         u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
1608         int i, j;
1609 
1610         sband = mp->hw->wiphy->bands[NL80211_BAND_2GHZ];
1611         if (!sband)
1612                 return;
1613 
1614         for (i = 0; i < sband->n_bitrates; i++) {
1615                 struct ieee80211_rate *rate = &sband->bitrates[i];
1616 
1617                 if (rate->flags & IEEE80211_RATE_ERP_G)
1618                         continue;
1619 
1620                 if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
1621                         continue;
1622 
1623                 for (j = 0; j < ARRAY_SIZE(bitrates); j++) {
1624                         if (rate->bitrate != bitrates[j])
1625                                 continue;
1626 
1627                         mp->cck_rates[j] = i;
1628                         break;
1629                 }
1630         }
1631 }
1632 
1633 static void *
1634 minstrel_ht_alloc(struct ieee80211_hw *hw)
1635 {
1636         struct minstrel_priv *mp;
1637 
1638         mp = kzalloc(sizeof(struct minstrel_priv), GFP_ATOMIC);
1639         if (!mp)
1640                 return NULL;
1641 
1642         mp->sample_switch = -1;
1643 
1644         /* contention window settings
1645          * Just an approximation. Using the per-queue values would complicate
1646          * the calculations and is probably unnecessary */
1647         mp->cw_min = 15;
1648         mp->cw_max = 1023;
1649 
1650         /* number of packets (in %) to use for sampling other rates
1651          * sample less often for non-mrr packets, because the overhead
1652          * is much higher than with mrr */
1653         mp->lookaround_rate = 5;
1654         mp->lookaround_rate_mrr = 10;
1655 
1656         /* maximum time that the hw is allowed to stay in one MRR segment */
1657         mp->segment_size = 6000;
1658 
1659         if (hw->max_rate_tries > 0)
1660                 mp->max_retry = hw->max_rate_tries;
1661         else
1662                 /* safe default, does not necessarily have to match hw properties */
1663                 mp->max_retry = 7;
1664 
1665         if (hw->max_rates >= 4)
1666                 mp->has_mrr = true;
1667 
1668         mp->hw = hw;
1669         mp->update_interval = 100;
1670 
1671         minstrel_ht_init_cck_rates(mp);
1672 
1673         return mp;
1674 }
1675 
1676 #ifdef CONFIG_MAC80211_DEBUGFS
1677 static void minstrel_ht_add_debugfs(struct ieee80211_hw *hw, void *priv,
1678                                     struct dentry *debugfsdir)
1679 {
1680         struct minstrel_priv *mp = priv;
1681 
1682         mp->fixed_rate_idx = (u32) -1;
1683         debugfs_create_u32("fixed_rate_idx", S_IRUGO | S_IWUGO, debugfsdir,
1684                            &mp->fixed_rate_idx);
1685         debugfs_create_u32("sample_switch", S_IRUGO | S_IWUSR, debugfsdir,
1686                            &mp->sample_switch);
1687 }
1688 #endif
1689 
1690 static void
1691 minstrel_ht_free(void *priv)
1692 {
1693         kfree(priv);
1694 }
1695 
1696 static u32 minstrel_ht_get_expected_throughput(void *priv_sta)
1697 {
1698         struct minstrel_ht_sta_priv *msp = priv_sta;
1699         struct minstrel_ht_sta *mi = &msp->ht;
1700         int i, j, prob, tp_avg;
1701 
1702         if (!msp->is_ht)
1703                 return mac80211_minstrel.get_expected_throughput(priv_sta);
1704 
1705         i = mi->max_tp_rate[0] / MCS_GROUP_RATES;
1706         j = mi->max_tp_rate[0] % MCS_GROUP_RATES;
1707         prob = mi->groups[i].rates[j].prob_ewma;
1708 
1709         /* convert tp_avg from pkt per second in kbps */
1710         tp_avg = minstrel_ht_get_tp_avg(mi, i, j, prob) * 10;
1711         tp_avg = tp_avg * AVG_PKT_SIZE * 8 / 1024;
1712 
1713         return tp_avg;
1714 }
1715 
1716 static const struct rate_control_ops mac80211_minstrel_ht = {
1717         .name = "minstrel_ht",
1718         .tx_status_ext = minstrel_ht_tx_status,
1719         .get_rate = minstrel_ht_get_rate,
1720         .rate_init = minstrel_ht_rate_init,
1721         .rate_update = minstrel_ht_rate_update,
1722         .alloc_sta = minstrel_ht_alloc_sta,
1723         .free_sta = minstrel_ht_free_sta,
1724         .alloc = minstrel_ht_alloc,
1725         .free = minstrel_ht_free,
1726 #ifdef CONFIG_MAC80211_DEBUGFS
1727         .add_debugfs = minstrel_ht_add_debugfs,
1728         .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
1729 #endif
1730         .get_expected_throughput = minstrel_ht_get_expected_throughput,
1731 };
1732 
1733 
1734 static void __init init_sample_table(void)
1735 {
1736         int col, i, new_idx;
1737         u8 rnd[MCS_GROUP_RATES];
1738 
1739         memset(sample_table, 0xff, sizeof(sample_table));
1740         for (col = 0; col < SAMPLE_COLUMNS; col++) {
1741                 prandom_bytes(rnd, sizeof(rnd));
1742                 for (i = 0; i < MCS_GROUP_RATES; i++) {
1743                         new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1744                         while (sample_table[col][new_idx] != 0xff)
1745                                 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1746 
1747                         sample_table[col][new_idx] = i;
1748                 }
1749         }
1750 }
1751 
1752 int __init
1753 rc80211_minstrel_init(void)
1754 {
1755         init_sample_table();
1756         return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1757 }
1758 
1759 void
1760 rc80211_minstrel_exit(void)
1761 {
1762         ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
1763 }

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