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Linux/net/mac80211/rc80211_minstrel_ht.c

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

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