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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)                                \
 56         [GROUP_IDX(_streams, _sgi, _ht40)] = {                          \
 57         .streams = _streams,                                            \
 58         .flags =                                                        \
 59                 IEEE80211_TX_RC_MCS |                                   \
 60                 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |                 \
 61                 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),             \
 62         .duration = {                                                   \
 63                 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26),          \
 64                 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52),         \
 65                 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78),         \
 66                 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104),        \
 67                 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156),        \
 68                 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208),        \
 69                 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234),        \
 70                 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260)         \
 71         }                                                               \
 72 }
 73 
 74 #define VHT_GROUP_IDX(_streams, _sgi, _bw)                              \
 75         (MINSTREL_VHT_GROUP_0 +                                         \
 76          MINSTREL_MAX_STREAMS * 2 * (_bw) +                             \
 77          MINSTREL_MAX_STREAMS * (_sgi) +                                \
 78          (_streams) - 1)
 79 
 80 #define BW2VBPS(_bw, r3, r2, r1)                                        \
 81         (_bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)
 82 
 83 #define VHT_GROUP(_streams, _sgi, _bw)                                  \
 84         [VHT_GROUP_IDX(_streams, _sgi, _bw)] = {                        \
 85         .streams = _streams,                                            \
 86         .flags =                                                        \
 87                 IEEE80211_TX_RC_VHT_MCS |                               \
 88                 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |                 \
 89                 (_bw == BW_80 ? IEEE80211_TX_RC_80_MHZ_WIDTH :          \
 90                  _bw == BW_40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),      \
 91         .duration = {                                                   \
 92                 MCS_DURATION(_streams, _sgi,                            \
 93                              BW2VBPS(_bw,  117,  54,  26)),             \
 94                 MCS_DURATION(_streams, _sgi,                            \
 95                              BW2VBPS(_bw,  234, 108,  52)),             \
 96                 MCS_DURATION(_streams, _sgi,                            \
 97                              BW2VBPS(_bw,  351, 162,  78)),             \
 98                 MCS_DURATION(_streams, _sgi,                            \
 99                              BW2VBPS(_bw,  468, 216, 104)),             \
100                 MCS_DURATION(_streams, _sgi,                            \
101                              BW2VBPS(_bw,  702, 324, 156)),             \
102                 MCS_DURATION(_streams, _sgi,                            \
103                              BW2VBPS(_bw,  936, 432, 208)),             \
104                 MCS_DURATION(_streams, _sgi,                            \
105                              BW2VBPS(_bw, 1053, 486, 234)),             \
106                 MCS_DURATION(_streams, _sgi,                            \
107                              BW2VBPS(_bw, 1170, 540, 260)),             \
108                 MCS_DURATION(_streams, _sgi,                            \
109                              BW2VBPS(_bw, 1404, 648, 312)),             \
110                 MCS_DURATION(_streams, _sgi,                            \
111                              BW2VBPS(_bw, 1560, 720, 346))              \
112         }                                                               \
113 }
114 
115 #define CCK_DURATION(_bitrate, _short, _len)            \
116         (1000 * (10 /* SIFS */ +                        \
117          (_short ? 72 + 24 : 144 + 48) +                \
118          (8 * (_len + 4) * 10) / (_bitrate)))
119 
120 #define CCK_ACK_DURATION(_bitrate, _short)                      \
121         (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) +   \
122          CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))
123 
124 #define CCK_DURATION_LIST(_short)                       \
125         CCK_ACK_DURATION(10, _short),                   \
126         CCK_ACK_DURATION(20, _short),                   \
127         CCK_ACK_DURATION(55, _short),                   \
128         CCK_ACK_DURATION(110, _short)
129 
130 #define CCK_GROUP                                       \
131         [MINSTREL_CCK_GROUP] = {                        \
132                 .streams = 0,                           \
133                 .flags = 0,                             \
134                 .duration = {                           \
135                         CCK_DURATION_LIST(false),       \
136                         CCK_DURATION_LIST(true)         \
137                 }                                       \
138         }
139 
140 #ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
141 static bool minstrel_vht_only = true;
142 module_param(minstrel_vht_only, bool, 0644);
143 MODULE_PARM_DESC(minstrel_vht_only,
144                  "Use only VHT rates when VHT is supported by sta.");
145 #endif
146 
147 /*
148  * To enable sufficiently targeted rate sampling, MCS rates are divided into
149  * groups, based on the number of streams and flags (HT40, SGI) that they
150  * use.
151  *
152  * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
153  * BW -> SGI -> #streams
154  */
155 const struct mcs_group minstrel_mcs_groups[] = {
156         MCS_GROUP(1, 0, BW_20),
157         MCS_GROUP(2, 0, BW_20),
158         MCS_GROUP(3, 0, BW_20),
159 
160         MCS_GROUP(1, 1, BW_20),
161         MCS_GROUP(2, 1, BW_20),
162         MCS_GROUP(3, 1, BW_20),
163 
164         MCS_GROUP(1, 0, BW_40),
165         MCS_GROUP(2, 0, BW_40),
166         MCS_GROUP(3, 0, BW_40),
167 
168         MCS_GROUP(1, 1, BW_40),
169         MCS_GROUP(2, 1, BW_40),
170         MCS_GROUP(3, 1, BW_40),
171 
172         CCK_GROUP,
173 
174 #ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
175         VHT_GROUP(1, 0, BW_20),
176         VHT_GROUP(2, 0, BW_20),
177         VHT_GROUP(3, 0, BW_20),
178 
179         VHT_GROUP(1, 1, BW_20),
180         VHT_GROUP(2, 1, BW_20),
181         VHT_GROUP(3, 1, BW_20),
182 
183         VHT_GROUP(1, 0, BW_40),
184         VHT_GROUP(2, 0, BW_40),
185         VHT_GROUP(3, 0, BW_40),
186 
187         VHT_GROUP(1, 1, BW_40),
188         VHT_GROUP(2, 1, BW_40),
189         VHT_GROUP(3, 1, BW_40),
190 
191         VHT_GROUP(1, 0, BW_80),
192         VHT_GROUP(2, 0, BW_80),
193         VHT_GROUP(3, 0, BW_80),
194 
195         VHT_GROUP(1, 1, BW_80),
196         VHT_GROUP(2, 1, BW_80),
197         VHT_GROUP(3, 1, BW_80),
198 #endif
199 };
200 
201 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
202 
203 static void
204 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
205 
206 /*
207  * Some VHT MCSes are invalid (when Ndbps / Nes is not an integer)
208  * e.g for MCS9@20MHzx1Nss: Ndbps=8x52*(5/6) Nes=1
209  *
210  * Returns the valid mcs map for struct minstrel_mcs_group_data.supported
211  */
212 static u16
213 minstrel_get_valid_vht_rates(int bw, int nss, __le16 mcs_map)
214 {
215         u16 mask = 0;
216 
217         if (bw == BW_20) {
218                 if (nss != 3 && nss != 6)
219                         mask = BIT(9);
220         } else if (bw == BW_80) {
221                 if (nss == 3 || nss == 7)
222                         mask = BIT(6);
223                 else if (nss == 6)
224                         mask = BIT(9);
225         } else {
226                 WARN_ON(bw != BW_40);
227         }
228 
229         switch ((le16_to_cpu(mcs_map) >> (2 * (nss - 1))) & 3) {
230         case IEEE80211_VHT_MCS_SUPPORT_0_7:
231                 mask |= 0x300;
232                 break;
233         case IEEE80211_VHT_MCS_SUPPORT_0_8:
234                 mask |= 0x200;
235                 break;
236         case IEEE80211_VHT_MCS_SUPPORT_0_9:
237                 break;
238         default:
239                 mask = 0x3ff;
240         }
241 
242         return 0x3ff & ~mask;
243 }
244 
245 /*
246  * Look up an MCS group index based on mac80211 rate information
247  */
248 static int
249 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
250 {
251         return GROUP_IDX((rate->idx / 8) + 1,
252                          !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
253                          !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
254 }
255 
256 static int
257 minstrel_vht_get_group_idx(struct ieee80211_tx_rate *rate)
258 {
259         return VHT_GROUP_IDX(ieee80211_rate_get_vht_nss(rate),
260                              !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
261                              !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH) +
262                              2*!!(rate->flags & IEEE80211_TX_RC_80_MHZ_WIDTH));
263 }
264 
265 static struct minstrel_rate_stats *
266 minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
267                       struct ieee80211_tx_rate *rate)
268 {
269         int group, idx;
270 
271         if (rate->flags & IEEE80211_TX_RC_MCS) {
272                 group = minstrel_ht_get_group_idx(rate);
273                 idx = rate->idx % 8;
274         } else if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
275                 group = minstrel_vht_get_group_idx(rate);
276                 idx = ieee80211_rate_get_vht_mcs(rate);
277         } else {
278                 group = MINSTREL_CCK_GROUP;
279 
280                 for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++)
281                         if (rate->idx == mp->cck_rates[idx])
282                                 break;
283 
284                 /* short preamble */
285                 if (!(mi->supported[group] & BIT(idx)))
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 
316         /*
317          * For the throughput calculation, limit the probability value to 90% to
318          * account for collision related packet error rate fluctuation
319          * (prob is scaled - see MINSTREL_FRAC above)
320          */
321         if (prob_ewma > MINSTREL_FRAC(90, 100))
322                 return MINSTREL_TRUNC(100000 * ((MINSTREL_FRAC(90, 100) * 1000)
323                                                                       / nsecs));
324         else
325                 return MINSTREL_TRUNC(100000 * ((prob_ewma * 1000) / nsecs));
326 }
327 
328 /*
329  * Find & sort topmost throughput rates
330  *
331  * If multiple rates provide equal throughput the sorting is based on their
332  * current success probability. Higher success probability is preferred among
333  * MCS groups, CCK rates do not provide aggregation and are therefore at last.
334  */
335 static void
336 minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u16 index,
337                                u16 *tp_list)
338 {
339         int cur_group, cur_idx, cur_tp_avg, cur_prob;
340         int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
341         int j = MAX_THR_RATES;
342 
343         cur_group = index / MCS_GROUP_RATES;
344         cur_idx = index  % MCS_GROUP_RATES;
345         cur_prob = mi->groups[cur_group].rates[cur_idx].prob_ewma;
346         cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx, cur_prob);
347 
348         do {
349                 tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
350                 tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
351                 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
352                 tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx,
353                                                     tmp_prob);
354                 if (cur_tp_avg < tmp_tp_avg ||
355                     (cur_tp_avg == tmp_tp_avg && cur_prob <= tmp_prob))
356                         break;
357                 j--;
358         } while (j > 0);
359 
360         if (j < MAX_THR_RATES - 1) {
361                 memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) *
362                        (MAX_THR_RATES - (j + 1))));
363         }
364         if (j < MAX_THR_RATES)
365                 tp_list[j] = index;
366 }
367 
368 /*
369  * Find and set the topmost probability rate per sta and per group
370  */
371 static void
372 minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 index)
373 {
374         struct minstrel_mcs_group_data *mg;
375         struct minstrel_rate_stats *mrs;
376         int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
377         int max_tp_group, cur_tp_avg, cur_group, cur_idx;
378         int max_gpr_group, max_gpr_idx;
379         int max_gpr_tp_avg, max_gpr_prob;
380 
381         cur_group = index / MCS_GROUP_RATES;
382         cur_idx = index % MCS_GROUP_RATES;
383         mg = &mi->groups[index / MCS_GROUP_RATES];
384         mrs = &mg->rates[index % MCS_GROUP_RATES];
385 
386         tmp_group = mi->max_prob_rate / MCS_GROUP_RATES;
387         tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES;
388         tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
389         tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
390 
391         /* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
392          * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
393         max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES;
394         if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) &&
395             (max_tp_group != MINSTREL_CCK_GROUP))
396                 return;
397 
398         max_gpr_group = mg->max_group_prob_rate / MCS_GROUP_RATES;
399         max_gpr_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
400         max_gpr_prob = mi->groups[max_gpr_group].rates[max_gpr_idx].prob_ewma;
401 
402         if (mrs->prob_ewma > MINSTREL_FRAC(75, 100)) {
403                 cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx,
404                                                     mrs->prob_ewma);
405                 if (cur_tp_avg > tmp_tp_avg)
406                         mi->max_prob_rate = index;
407 
408                 max_gpr_tp_avg = minstrel_ht_get_tp_avg(mi, max_gpr_group,
409                                                         max_gpr_idx,
410                                                         max_gpr_prob);
411                 if (cur_tp_avg > max_gpr_tp_avg)
412                         mg->max_group_prob_rate = index;
413         } else {
414                 if (mrs->prob_ewma > tmp_prob)
415                         mi->max_prob_rate = index;
416                 if (mrs->prob_ewma > max_gpr_prob)
417                         mg->max_group_prob_rate = index;
418         }
419 }
420 
421 
422 /*
423  * Assign new rate set per sta and use CCK rates only if the fastest
424  * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted
425  * rate sets where MCS and CCK rates are mixed, because CCK rates can
426  * not use aggregation.
427  */
428 static void
429 minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi,
430                                  u16 tmp_mcs_tp_rate[MAX_THR_RATES],
431                                  u16 tmp_cck_tp_rate[MAX_THR_RATES])
432 {
433         unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp, tmp_prob;
434         int i;
435 
436         tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES;
437         tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES;
438         tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
439         tmp_cck_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
440 
441         tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES;
442         tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES;
443         tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
444         tmp_mcs_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
445 
446         if (tmp_cck_tp > tmp_mcs_tp) {
447                 for(i = 0; i < MAX_THR_RATES; i++) {
448                         minstrel_ht_sort_best_tp_rates(mi, tmp_cck_tp_rate[i],
449                                                        tmp_mcs_tp_rate);
450                 }
451         }
452 
453 }
454 
455 /*
456  * Try to increase robustness of max_prob rate by decrease number of
457  * streams if possible.
458  */
459 static inline void
460 minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
461 {
462         struct minstrel_mcs_group_data *mg;
463         int tmp_max_streams, group, tmp_idx, tmp_prob;
464         int tmp_tp = 0;
465 
466         tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
467                           MCS_GROUP_RATES].streams;
468         for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
469                 mg = &mi->groups[group];
470                 if (!mi->supported[group] || group == MINSTREL_CCK_GROUP)
471                         continue;
472 
473                 tmp_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
474                 tmp_prob = mi->groups[group].rates[tmp_idx].prob_ewma;
475 
476                 if (tmp_tp < minstrel_ht_get_tp_avg(mi, group, tmp_idx, tmp_prob) &&
477                    (minstrel_mcs_groups[group].streams < tmp_max_streams)) {
478                                 mi->max_prob_rate = mg->max_group_prob_rate;
479                                 tmp_tp = minstrel_ht_get_tp_avg(mi, group,
480                                                                 tmp_idx,
481                                                                 tmp_prob);
482                 }
483         }
484 }
485 
486 /*
487  * Update rate statistics and select new primary rates
488  *
489  * Rules for rate selection:
490  *  - max_prob_rate must use only one stream, as a tradeoff between delivery
491  *    probability and throughput during strong fluctuations
492  *  - as long as the max prob rate has a probability of more than 75%, pick
493  *    higher throughput rates, even if the probablity is a bit lower
494  */
495 static void
496 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
497 {
498         struct minstrel_mcs_group_data *mg;
499         struct minstrel_rate_stats *mrs;
500         int group, i, j, cur_prob;
501         u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
502         u16 tmp_cck_tp_rate[MAX_THR_RATES], index;
503 
504         if (mi->ampdu_packets > 0) {
505                 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
506                         MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
507                 mi->ampdu_len = 0;
508                 mi->ampdu_packets = 0;
509         }
510 
511         mi->sample_slow = 0;
512         mi->sample_count = 0;
513 
514         /* Initialize global rate indexes */
515         for(j = 0; j < MAX_THR_RATES; j++){
516                 tmp_mcs_tp_rate[j] = 0;
517                 tmp_cck_tp_rate[j] = 0;
518         }
519 
520         /* Find best rate sets within all MCS groups*/
521         for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
522 
523                 mg = &mi->groups[group];
524                 if (!mi->supported[group])
525                         continue;
526 
527                 mi->sample_count++;
528 
529                 /* (re)Initialize group rate indexes */
530                 for(j = 0; j < MAX_THR_RATES; j++)
531                         tmp_group_tp_rate[j] = group;
532 
533                 for (i = 0; i < MCS_GROUP_RATES; i++) {
534                         if (!(mi->supported[group] & BIT(i)))
535                                 continue;
536 
537                         index = MCS_GROUP_RATES * group + i;
538 
539                         mrs = &mg->rates[i];
540                         mrs->retry_updated = false;
541                         minstrel_calc_rate_stats(mrs);
542                         cur_prob = mrs->prob_ewma;
543 
544                         if (minstrel_ht_get_tp_avg(mi, group, i, cur_prob) == 0)
545                                 continue;
546 
547                         /* Find max throughput rate set */
548                         if (group != MINSTREL_CCK_GROUP) {
549                                 minstrel_ht_sort_best_tp_rates(mi, index,
550                                                                tmp_mcs_tp_rate);
551                         } else if (group == MINSTREL_CCK_GROUP) {
552                                 minstrel_ht_sort_best_tp_rates(mi, index,
553                                                                tmp_cck_tp_rate);
554                         }
555 
556                         /* Find max throughput rate set within a group */
557                         minstrel_ht_sort_best_tp_rates(mi, index,
558                                                        tmp_group_tp_rate);
559 
560                         /* Find max probability rate per group and global */
561                         minstrel_ht_set_best_prob_rate(mi, index);
562                 }
563 
564                 memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
565                        sizeof(mg->max_group_tp_rate));
566         }
567 
568         /* Assign new rate set per sta */
569         minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate);
570         memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));
571 
572         /* Try to increase robustness of max_prob_rate*/
573         minstrel_ht_prob_rate_reduce_streams(mi);
574 
575         /* try to sample all available rates during each interval */
576         mi->sample_count *= 8;
577 
578 #ifdef CONFIG_MAC80211_DEBUGFS
579         /* use fixed index if set */
580         if (mp->fixed_rate_idx != -1) {
581                 for (i = 0; i < 4; i++)
582                         mi->max_tp_rate[i] = mp->fixed_rate_idx;
583                 mi->max_prob_rate = mp->fixed_rate_idx;
584         }
585 #endif
586 
587         /* Reset update timer */
588         mi->last_stats_update = jiffies;
589 }
590 
591 static bool
592 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
593 {
594         if (rate->idx < 0)
595                 return false;
596 
597         if (!rate->count)
598                 return false;
599 
600         if (rate->flags & IEEE80211_TX_RC_MCS ||
601             rate->flags & IEEE80211_TX_RC_VHT_MCS)
602                 return true;
603 
604         return rate->idx == mp->cck_rates[0] ||
605                rate->idx == mp->cck_rates[1] ||
606                rate->idx == mp->cck_rates[2] ||
607                rate->idx == mp->cck_rates[3];
608 }
609 
610 static void
611 minstrel_set_next_sample_idx(struct minstrel_ht_sta *mi)
612 {
613         struct minstrel_mcs_group_data *mg;
614 
615         for (;;) {
616                 mi->sample_group++;
617                 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
618                 mg = &mi->groups[mi->sample_group];
619 
620                 if (!mi->supported[mi->sample_group])
621                         continue;
622 
623                 if (++mg->index >= MCS_GROUP_RATES) {
624                         mg->index = 0;
625                         if (++mg->column >= ARRAY_SIZE(sample_table))
626                                 mg->column = 0;
627                 }
628                 break;
629         }
630 }
631 
632 static void
633 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u16 *idx, bool primary)
634 {
635         int group, orig_group;
636 
637         orig_group = group = *idx / MCS_GROUP_RATES;
638         while (group > 0) {
639                 group--;
640 
641                 if (!mi->supported[group])
642                         continue;
643 
644                 if (minstrel_mcs_groups[group].streams >
645                     minstrel_mcs_groups[orig_group].streams)
646                         continue;
647 
648                 if (primary)
649                         *idx = mi->groups[group].max_group_tp_rate[0];
650                 else
651                         *idx = mi->groups[group].max_group_tp_rate[1];
652                 break;
653         }
654 }
655 
656 static void
657 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
658 {
659         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
660         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
661         u16 tid;
662 
663         if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
664                 return;
665 
666         if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
667                 return;
668 
669         if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
670                 return;
671 
672         tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
673         if (likely(sta->ampdu_mlme.tid_tx[tid]))
674                 return;
675 
676         ieee80211_start_tx_ba_session(pubsta, tid, 0);
677 }
678 
679 static void
680 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
681                       void *priv_sta, struct ieee80211_tx_status *st)
682 {
683         struct ieee80211_tx_info *info = st->info;
684         struct minstrel_ht_sta_priv *msp = priv_sta;
685         struct minstrel_ht_sta *mi = &msp->ht;
686         struct ieee80211_tx_rate *ar = info->status.rates;
687         struct minstrel_rate_stats *rate, *rate2;
688         struct minstrel_priv *mp = priv;
689         bool last, update = false;
690         int i;
691 
692         if (!msp->is_ht)
693                 return mac80211_minstrel.tx_status_ext(priv, sband,
694                                                        &msp->legacy, st);
695 
696         /* This packet was aggregated but doesn't carry status info */
697         if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
698             !(info->flags & IEEE80211_TX_STAT_AMPDU))
699                 return;
700 
701         if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
702                 info->status.ampdu_ack_len =
703                         (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
704                 info->status.ampdu_len = 1;
705         }
706 
707         mi->ampdu_packets++;
708         mi->ampdu_len += info->status.ampdu_len;
709 
710         if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
711                 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
712                 mi->sample_tries = 1;
713                 mi->sample_count--;
714         }
715 
716         if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
717                 mi->sample_packets += info->status.ampdu_len;
718 
719         last = !minstrel_ht_txstat_valid(mp, &ar[0]);
720         for (i = 0; !last; i++) {
721                 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
722                        !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
723 
724                 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
725 
726                 if (last)
727                         rate->success += info->status.ampdu_ack_len;
728 
729                 rate->attempts += ar[i].count * info->status.ampdu_len;
730         }
731 
732         /*
733          * check for sudden death of spatial multiplexing,
734          * downgrade to a lower number of streams if necessary.
735          */
736         rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
737         if (rate->attempts > 30 &&
738             MINSTREL_FRAC(rate->success, rate->attempts) <
739             MINSTREL_FRAC(20, 100)) {
740                 minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
741                 update = true;
742         }
743 
744         rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
745         if (rate2->attempts > 30 &&
746             MINSTREL_FRAC(rate2->success, rate2->attempts) <
747             MINSTREL_FRAC(20, 100)) {
748                 minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
749                 update = true;
750         }
751 
752         if (time_after(jiffies, mi->last_stats_update +
753                                 (mp->update_interval / 2 * HZ) / 1000)) {
754                 update = true;
755                 minstrel_ht_update_stats(mp, mi);
756         }
757 
758         if (update)
759                 minstrel_ht_update_rates(mp, mi);
760 }
761 
762 static void
763 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
764                          int index)
765 {
766         struct minstrel_rate_stats *mrs;
767         const struct mcs_group *group;
768         unsigned int tx_time, tx_time_rtscts, tx_time_data;
769         unsigned int cw = mp->cw_min;
770         unsigned int ctime = 0;
771         unsigned int t_slot = 9; /* FIXME */
772         unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
773         unsigned int overhead = 0, overhead_rtscts = 0;
774 
775         mrs = minstrel_get_ratestats(mi, index);
776         if (mrs->prob_ewma < MINSTREL_FRAC(1, 10)) {
777                 mrs->retry_count = 1;
778                 mrs->retry_count_rtscts = 1;
779                 return;
780         }
781 
782         mrs->retry_count = 2;
783         mrs->retry_count_rtscts = 2;
784         mrs->retry_updated = true;
785 
786         group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
787         tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
788 
789         /* Contention time for first 2 tries */
790         ctime = (t_slot * cw) >> 1;
791         cw = min((cw << 1) | 1, mp->cw_max);
792         ctime += (t_slot * cw) >> 1;
793         cw = min((cw << 1) | 1, mp->cw_max);
794 
795         if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
796                 overhead = mi->overhead;
797                 overhead_rtscts = mi->overhead_rtscts;
798         }
799 
800         /* Total TX time for data and Contention after first 2 tries */
801         tx_time = ctime + 2 * (overhead + tx_time_data);
802         tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
803 
804         /* See how many more tries we can fit inside segment size */
805         do {
806                 /* Contention time for this try */
807                 ctime = (t_slot * cw) >> 1;
808                 cw = min((cw << 1) | 1, mp->cw_max);
809 
810                 /* Total TX time after this try */
811                 tx_time += ctime + overhead + tx_time_data;
812                 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
813 
814                 if (tx_time_rtscts < mp->segment_size)
815                         mrs->retry_count_rtscts++;
816         } while ((tx_time < mp->segment_size) &&
817                  (++mrs->retry_count < mp->max_retry));
818 }
819 
820 
821 static void
822 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
823                      struct ieee80211_sta_rates *ratetbl, int offset, int index)
824 {
825         const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
826         struct minstrel_rate_stats *mrs;
827         u8 idx;
828         u16 flags = group->flags;
829 
830         mrs = minstrel_get_ratestats(mi, index);
831         if (!mrs->retry_updated)
832                 minstrel_calc_retransmit(mp, mi, index);
833 
834         if (mrs->prob_ewma < MINSTREL_FRAC(20, 100) || !mrs->retry_count) {
835                 ratetbl->rate[offset].count = 2;
836                 ratetbl->rate[offset].count_rts = 2;
837                 ratetbl->rate[offset].count_cts = 2;
838         } else {
839                 ratetbl->rate[offset].count = mrs->retry_count;
840                 ratetbl->rate[offset].count_cts = mrs->retry_count;
841                 ratetbl->rate[offset].count_rts = mrs->retry_count_rtscts;
842         }
843 
844         if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP)
845                 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
846         else if (flags & IEEE80211_TX_RC_VHT_MCS)
847                 idx = ((group->streams - 1) << 4) |
848                       ((index % MCS_GROUP_RATES) & 0xF);
849         else
850                 idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;
851 
852         /* enable RTS/CTS if needed:
853          *  - if station is in dynamic SMPS (and streams > 1)
854          *  - for fallback rates, to increase chances of getting through
855          */
856         if (offset > 0 ||
857             (mi->sta->smps_mode == IEEE80211_SMPS_DYNAMIC &&
858              group->streams > 1)) {
859                 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
860                 flags |= IEEE80211_TX_RC_USE_RTS_CTS;
861         }
862 
863         ratetbl->rate[offset].idx = idx;
864         ratetbl->rate[offset].flags = flags;
865 }
866 
867 static inline int
868 minstrel_ht_get_prob_ewma(struct minstrel_ht_sta *mi, int rate)
869 {
870         int group = rate / MCS_GROUP_RATES;
871         rate %= MCS_GROUP_RATES;
872         return mi->groups[group].rates[rate].prob_ewma;
873 }
874 
875 static int
876 minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta *mi)
877 {
878         int group = mi->max_prob_rate / MCS_GROUP_RATES;
879         const struct mcs_group *g = &minstrel_mcs_groups[group];
880         int rate = mi->max_prob_rate % MCS_GROUP_RATES;
881 
882         /* Disable A-MSDU if max_prob_rate is bad */
883         if (mi->groups[group].rates[rate].prob_ewma < MINSTREL_FRAC(50, 100))
884                 return 1;
885 
886         /* If the rate is slower than single-stream MCS1, make A-MSDU limit small */
887         if (g->duration[rate] > MCS_DURATION(1, 0, 52))
888                 return 500;
889 
890         /*
891          * If the rate is slower than single-stream MCS4, limit A-MSDU to usual
892          * data packet size
893          */
894         if (g->duration[rate] > MCS_DURATION(1, 0, 104))
895                 return 1600;
896 
897         /*
898          * If the rate is slower than single-stream MCS7, or if the max throughput
899          * rate success probability is less than 75%, limit A-MSDU to twice the usual
900          * data packet size
901          */
902         if (g->duration[rate] > MCS_DURATION(1, 0, 260) ||
903             (minstrel_ht_get_prob_ewma(mi, mi->max_tp_rate[0]) <
904              MINSTREL_FRAC(75, 100)))
905                 return 3200;
906 
907         /*
908          * HT A-MPDU limits maximum MPDU size under BA agreement to 4095 bytes.
909          * Since aggregation sessions are started/stopped without txq flush, use
910          * the limit here to avoid the complexity of having to de-aggregate
911          * packets in the queue.
912          */
913         if (!mi->sta->vht_cap.vht_supported)
914                 return IEEE80211_MAX_MPDU_LEN_HT_BA;
915 
916         /* unlimited */
917         return 0;
918 }
919 
920 static void
921 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
922 {
923         struct ieee80211_sta_rates *rates;
924         int i = 0;
925 
926         rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
927         if (!rates)
928                 return;
929 
930         /* Start with max_tp_rate[0] */
931         minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
932 
933         if (mp->hw->max_rates >= 3) {
934                 /* At least 3 tx rates supported, use max_tp_rate[1] next */
935                 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]);
936         }
937 
938         if (mp->hw->max_rates >= 2) {
939                 /*
940                  * At least 2 tx rates supported, use max_prob_rate next */
941                 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
942         }
943 
944         mi->sta->max_rc_amsdu_len = minstrel_ht_get_max_amsdu_len(mi);
945         rates->rate[i].idx = -1;
946         rate_control_set_rates(mp->hw, mi->sta, rates);
947 }
948 
949 static inline int
950 minstrel_get_duration(int index)
951 {
952         const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
953         return group->duration[index % MCS_GROUP_RATES];
954 }
955 
956 static int
957 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
958 {
959         struct minstrel_rate_stats *mrs;
960         struct minstrel_mcs_group_data *mg;
961         unsigned int sample_dur, sample_group, cur_max_tp_streams;
962         int tp_rate1, tp_rate2;
963         int sample_idx = 0;
964 
965         if (mi->sample_wait > 0) {
966                 mi->sample_wait--;
967                 return -1;
968         }
969 
970         if (!mi->sample_tries)
971                 return -1;
972 
973         sample_group = mi->sample_group;
974         mg = &mi->groups[sample_group];
975         sample_idx = sample_table[mg->column][mg->index];
976         minstrel_set_next_sample_idx(mi);
977 
978         if (!(mi->supported[sample_group] & BIT(sample_idx)))
979                 return -1;
980 
981         mrs = &mg->rates[sample_idx];
982         sample_idx += sample_group * MCS_GROUP_RATES;
983 
984         /* Set tp_rate1, tp_rate2 to the highest / second highest max_tp_rate */
985         if (minstrel_get_duration(mi->max_tp_rate[0]) >
986             minstrel_get_duration(mi->max_tp_rate[1])) {
987                 tp_rate1 = mi->max_tp_rate[1];
988                 tp_rate2 = mi->max_tp_rate[0];
989         } else {
990                 tp_rate1 = mi->max_tp_rate[0];
991                 tp_rate2 = mi->max_tp_rate[1];
992         }
993 
994         /*
995          * Sampling might add some overhead (RTS, no aggregation)
996          * to the frame. Hence, don't use sampling for the highest currently
997          * used highest throughput or probability rate.
998          */
999         if (sample_idx == mi->max_tp_rate[0] || sample_idx == mi->max_prob_rate)
1000                 return -1;
1001 
1002         /*
1003          * Do not sample if the probability is already higher than 95%
1004          * to avoid wasting airtime.
1005          */
1006         if (mrs->prob_ewma > MINSTREL_FRAC(95, 100))
1007                 return -1;
1008 
1009         /*
1010          * Make sure that lower rates get sampled only occasionally,
1011          * if the link is working perfectly.
1012          */
1013 
1014         cur_max_tp_streams = minstrel_mcs_groups[tp_rate1 /
1015                 MCS_GROUP_RATES].streams;
1016         sample_dur = minstrel_get_duration(sample_idx);
1017         if (sample_dur >= minstrel_get_duration(tp_rate2) &&
1018             (cur_max_tp_streams - 1 <
1019              minstrel_mcs_groups[sample_group].streams ||
1020              sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
1021                 if (mrs->sample_skipped < 20)
1022                         return -1;
1023 
1024                 if (mi->sample_slow++ > 2)
1025                         return -1;
1026         }
1027         mi->sample_tries--;
1028 
1029         return sample_idx;
1030 }
1031 
1032 static void
1033 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
1034                      struct ieee80211_tx_rate_control *txrc)
1035 {
1036         const struct mcs_group *sample_group;
1037         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
1038         struct ieee80211_tx_rate *rate = &info->status.rates[0];
1039         struct minstrel_ht_sta_priv *msp = priv_sta;
1040         struct minstrel_ht_sta *mi = &msp->ht;
1041         struct minstrel_priv *mp = priv;
1042         int sample_idx;
1043 
1044         if (rate_control_send_low(sta, priv_sta, txrc))
1045                 return;
1046 
1047         if (!msp->is_ht)
1048                 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
1049 
1050         if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
1051             mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
1052                 minstrel_aggr_check(sta, txrc->skb);
1053 
1054         info->flags |= mi->tx_flags;
1055 
1056 #ifdef CONFIG_MAC80211_DEBUGFS
1057         if (mp->fixed_rate_idx != -1)
1058                 return;
1059 #endif
1060 
1061         /* Don't use EAPOL frames for sampling on non-mrr hw */
1062         if (mp->hw->max_rates == 1 &&
1063             (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
1064                 sample_idx = -1;
1065         else
1066                 sample_idx = minstrel_get_sample_rate(mp, mi);
1067 
1068         mi->total_packets++;
1069 
1070         /* wraparound */
1071         if (mi->total_packets == ~0) {
1072                 mi->total_packets = 0;
1073                 mi->sample_packets = 0;
1074         }
1075 
1076         if (sample_idx < 0)
1077                 return;
1078 
1079         sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
1080         info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
1081         rate->count = 1;
1082 
1083         if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
1084                 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
1085                 rate->idx = mp->cck_rates[idx];
1086         } else if (sample_group->flags & IEEE80211_TX_RC_VHT_MCS) {
1087                 ieee80211_rate_set_vht(rate, sample_idx % MCS_GROUP_RATES,
1088                                        sample_group->streams);
1089         } else {
1090                 rate->idx = sample_idx % MCS_GROUP_RATES +
1091                             (sample_group->streams - 1) * 8;
1092         }
1093 
1094         rate->flags = sample_group->flags;
1095 }
1096 
1097 static void
1098 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1099                        struct ieee80211_supported_band *sband,
1100                        struct ieee80211_sta *sta)
1101 {
1102         int i;
1103 
1104         if (sband->band != NL80211_BAND_2GHZ)
1105                 return;
1106 
1107         if (!ieee80211_hw_check(mp->hw, SUPPORTS_HT_CCK_RATES))
1108                 return;
1109 
1110         mi->cck_supported = 0;
1111         mi->cck_supported_short = 0;
1112         for (i = 0; i < 4; i++) {
1113                 if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
1114                         continue;
1115 
1116                 mi->cck_supported |= BIT(i);
1117                 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
1118                         mi->cck_supported_short |= BIT(i);
1119         }
1120 
1121         mi->supported[MINSTREL_CCK_GROUP] = mi->cck_supported;
1122 }
1123 
1124 static void
1125 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
1126                         struct cfg80211_chan_def *chandef,
1127                         struct ieee80211_sta *sta, void *priv_sta)
1128 {
1129         struct minstrel_priv *mp = priv;
1130         struct minstrel_ht_sta_priv *msp = priv_sta;
1131         struct minstrel_ht_sta *mi = &msp->ht;
1132         struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
1133         u16 sta_cap = sta->ht_cap.cap;
1134         struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap;
1135         struct sta_info *sinfo = container_of(sta, struct sta_info, sta);
1136         int use_vht;
1137         int n_supported = 0;
1138         int ack_dur;
1139         int stbc;
1140         int i;
1141 
1142         /* fall back to the old minstrel for legacy stations */
1143         if (!sta->ht_cap.ht_supported)
1144                 goto use_legacy;
1145 
1146         BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != MINSTREL_GROUPS_NB);
1147 
1148 #ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
1149         if (vht_cap->vht_supported)
1150                 use_vht = vht_cap->vht_mcs.tx_mcs_map != cpu_to_le16(~0);
1151         else
1152 #endif
1153         use_vht = 0;
1154 
1155         msp->is_ht = true;
1156         memset(mi, 0, sizeof(*mi));
1157 
1158         mi->sta = sta;
1159         mi->last_stats_update = jiffies;
1160 
1161         ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
1162         mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
1163         mi->overhead += ack_dur;
1164         mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
1165 
1166         mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
1167 
1168         /* When using MRR, sample more on the first attempt, without delay */
1169         if (mp->has_mrr) {
1170                 mi->sample_count = 16;
1171                 mi->sample_wait = 0;
1172         } else {
1173                 mi->sample_count = 8;
1174                 mi->sample_wait = 8;
1175         }
1176         mi->sample_tries = 4;
1177 
1178         /* TODO tx_flags for vht - ATM the RC API is not fine-grained enough */
1179         if (!use_vht) {
1180                 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
1181                         IEEE80211_HT_CAP_RX_STBC_SHIFT;
1182                 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
1183 
1184                 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
1185                         mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
1186         }
1187 
1188         for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
1189                 u32 gflags = minstrel_mcs_groups[i].flags;
1190                 int bw, nss;
1191 
1192                 mi->supported[i] = 0;
1193                 if (i == MINSTREL_CCK_GROUP) {
1194                         minstrel_ht_update_cck(mp, mi, sband, sta);
1195                         continue;
1196                 }
1197 
1198                 if (gflags & IEEE80211_TX_RC_SHORT_GI) {
1199                         if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
1200                                 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
1201                                         continue;
1202                         } else {
1203                                 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
1204                                         continue;
1205                         }
1206                 }
1207 
1208                 if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
1209                     sta->bandwidth < IEEE80211_STA_RX_BW_40)
1210                         continue;
1211 
1212                 nss = minstrel_mcs_groups[i].streams;
1213 
1214                 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
1215                 if (sta->smps_mode == IEEE80211_SMPS_STATIC && nss > 1)
1216                         continue;
1217 
1218                 /* HT rate */
1219                 if (gflags & IEEE80211_TX_RC_MCS) {
1220 #ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
1221                         if (use_vht && minstrel_vht_only)
1222                                 continue;
1223 #endif
1224                         mi->supported[i] = mcs->rx_mask[nss - 1];
1225                         if (mi->supported[i])
1226                                 n_supported++;
1227                         continue;
1228                 }
1229 
1230                 /* VHT rate */
1231                 if (!vht_cap->vht_supported ||
1232                     WARN_ON(!(gflags & IEEE80211_TX_RC_VHT_MCS)) ||
1233                     WARN_ON(gflags & IEEE80211_TX_RC_160_MHZ_WIDTH))
1234                         continue;
1235 
1236                 if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH) {
1237                         if (sta->bandwidth < IEEE80211_STA_RX_BW_80 ||
1238                             ((gflags & IEEE80211_TX_RC_SHORT_GI) &&
1239                              !(vht_cap->cap & IEEE80211_VHT_CAP_SHORT_GI_80))) {
1240                                 continue;
1241                         }
1242                 }
1243 
1244                 if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH)
1245                         bw = BW_40;
1246                 else if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH)
1247                         bw = BW_80;
1248                 else
1249                         bw = BW_20;
1250 
1251                 mi->supported[i] = minstrel_get_valid_vht_rates(bw, nss,
1252                                 vht_cap->vht_mcs.tx_mcs_map);
1253 
1254                 if (mi->supported[i])
1255                         n_supported++;
1256         }
1257 
1258         if (!n_supported)
1259                 goto use_legacy;
1260 
1261         if (test_sta_flag(sinfo, WLAN_STA_SHORT_PREAMBLE))
1262                 mi->cck_supported_short |= mi->cck_supported_short << 4;
1263 
1264         /* create an initial rate table with the lowest supported rates */
1265         minstrel_ht_update_stats(mp, mi);
1266         minstrel_ht_update_rates(mp, mi);
1267 
1268         return;
1269 
1270 use_legacy:
1271         msp->is_ht = false;
1272         memset(&msp->legacy, 0, sizeof(msp->legacy));
1273         msp->legacy.r = msp->ratelist;
1274         msp->legacy.sample_table = msp->sample_table;
1275         return mac80211_minstrel.rate_init(priv, sband, chandef, sta,
1276                                            &msp->legacy);
1277 }
1278 
1279 static void
1280 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
1281                       struct cfg80211_chan_def *chandef,
1282                       struct ieee80211_sta *sta, void *priv_sta)
1283 {
1284         minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1285 }
1286 
1287 static void
1288 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
1289                         struct cfg80211_chan_def *chandef,
1290                         struct ieee80211_sta *sta, void *priv_sta,
1291                         u32 changed)
1292 {
1293         minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1294 }
1295 
1296 static void *
1297 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
1298 {
1299         struct ieee80211_supported_band *sband;
1300         struct minstrel_ht_sta_priv *msp;
1301         struct minstrel_priv *mp = priv;
1302         struct ieee80211_hw *hw = mp->hw;
1303         int max_rates = 0;
1304         int i;
1305 
1306         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1307                 sband = hw->wiphy->bands[i];
1308                 if (sband && sband->n_bitrates > max_rates)
1309                         max_rates = sband->n_bitrates;
1310         }
1311 
1312         msp = kzalloc(sizeof(*msp), gfp);
1313         if (!msp)
1314                 return NULL;
1315 
1316         msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
1317         if (!msp->ratelist)
1318                 goto error;
1319 
1320         msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
1321         if (!msp->sample_table)
1322                 goto error1;
1323 
1324         return msp;
1325 
1326 error1:
1327         kfree(msp->ratelist);
1328 error:
1329         kfree(msp);
1330         return NULL;
1331 }
1332 
1333 static void
1334 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1335 {
1336         struct minstrel_ht_sta_priv *msp = priv_sta;
1337 
1338         kfree(msp->sample_table);
1339         kfree(msp->ratelist);
1340         kfree(msp);
1341 }
1342 
1343 static void *
1344 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
1345 {
1346         return mac80211_minstrel.alloc(hw, debugfsdir);
1347 }
1348 
1349 static void
1350 minstrel_ht_free(void *priv)
1351 {
1352         mac80211_minstrel.free(priv);
1353 }
1354 
1355 static u32 minstrel_ht_get_expected_throughput(void *priv_sta)
1356 {
1357         struct minstrel_ht_sta_priv *msp = priv_sta;
1358         struct minstrel_ht_sta *mi = &msp->ht;
1359         int i, j, prob, tp_avg;
1360 
1361         if (!msp->is_ht)
1362                 return mac80211_minstrel.get_expected_throughput(priv_sta);
1363 
1364         i = mi->max_tp_rate[0] / MCS_GROUP_RATES;
1365         j = mi->max_tp_rate[0] % MCS_GROUP_RATES;
1366         prob = mi->groups[i].rates[j].prob_ewma;
1367 
1368         /* convert tp_avg from pkt per second in kbps */
1369         tp_avg = minstrel_ht_get_tp_avg(mi, i, j, prob) * 10;
1370         tp_avg = tp_avg * AVG_PKT_SIZE * 8 / 1024;
1371 
1372         return tp_avg;
1373 }
1374 
1375 static const struct rate_control_ops mac80211_minstrel_ht = {
1376         .name = "minstrel_ht",
1377         .tx_status_ext = minstrel_ht_tx_status,
1378         .get_rate = minstrel_ht_get_rate,
1379         .rate_init = minstrel_ht_rate_init,
1380         .rate_update = minstrel_ht_rate_update,
1381         .alloc_sta = minstrel_ht_alloc_sta,
1382         .free_sta = minstrel_ht_free_sta,
1383         .alloc = minstrel_ht_alloc,
1384         .free = minstrel_ht_free,
1385 #ifdef CONFIG_MAC80211_DEBUGFS
1386         .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
1387         .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
1388 #endif
1389         .get_expected_throughput = minstrel_ht_get_expected_throughput,
1390 };
1391 
1392 
1393 static void __init init_sample_table(void)
1394 {
1395         int col, i, new_idx;
1396         u8 rnd[MCS_GROUP_RATES];
1397 
1398         memset(sample_table, 0xff, sizeof(sample_table));
1399         for (col = 0; col < SAMPLE_COLUMNS; col++) {
1400                 prandom_bytes(rnd, sizeof(rnd));
1401                 for (i = 0; i < MCS_GROUP_RATES; i++) {
1402                         new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1403                         while (sample_table[col][new_idx] != 0xff)
1404                                 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1405 
1406                         sample_table[col][new_idx] = i;
1407                 }
1408         }
1409 }
1410 
1411 int __init
1412 rc80211_minstrel_ht_init(void)
1413 {
1414         init_sample_table();
1415         return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1416 }
1417 
1418 void
1419 rc80211_minstrel_ht_exit(void)
1420 {
1421         ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
1422 }
1423 

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