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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 "rc80211_minstrel.h"
 18 #include "rc80211_minstrel_ht.h"
 19 
 20 #define AVG_AMPDU_SIZE  16
 21 #define AVG_PKT_SIZE    1200
 22 
 23 /* Number of bits for an average sized packet */
 24 #define MCS_NBITS ((AVG_PKT_SIZE * AVG_AMPDU_SIZE) << 3)
 25 
 26 /* Number of symbols for a packet with (bps) bits per symbol */
 27 #define MCS_NSYMS(bps) DIV_ROUND_UP(MCS_NBITS, (bps))
 28 
 29 /* Transmission time (nanoseconds) for a packet containing (syms) symbols */
 30 #define MCS_SYMBOL_TIME(sgi, syms)                                      \
 31         (sgi ?                                                          \
 32           ((syms) * 18000 + 4000) / 5 : /* syms * 3.6 us */             \
 33           ((syms) * 1000) << 2          /* syms * 4 us */               \
 34         )
 35 
 36 /* Transmit duration for the raw data part of an average sized packet */
 37 #define MCS_DURATION(streams, sgi, bps) \
 38         (MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps))) / AVG_AMPDU_SIZE)
 39 
 40 #define BW_20                   0
 41 #define BW_40                   1
 42 #define BW_80                   2
 43 
 44 /*
 45  * Define group sort order: HT40 -> SGI -> #streams
 46  */
 47 #define GROUP_IDX(_streams, _sgi, _ht40)        \
 48         MINSTREL_HT_GROUP_0 +                   \
 49         MINSTREL_MAX_STREAMS * 2 * _ht40 +      \
 50         MINSTREL_MAX_STREAMS * _sgi +   \
 51         _streams - 1
 52 
 53 /* MCS rate information for an MCS group */
 54 #define MCS_GROUP(_streams, _sgi, _ht40)                                \
 55         [GROUP_IDX(_streams, _sgi, _ht40)] = {                          \
 56         .streams = _streams,                                            \
 57         .flags =                                                        \
 58                 IEEE80211_TX_RC_MCS |                                   \
 59                 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |                 \
 60                 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),             \
 61         .duration = {                                                   \
 62                 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26),          \
 63                 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52),         \
 64                 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78),         \
 65                 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104),        \
 66                 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156),        \
 67                 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208),        \
 68                 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234),        \
 69                 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260)         \
 70         }                                                               \
 71 }
 72 
 73 #define VHT_GROUP_IDX(_streams, _sgi, _bw)                              \
 74         (MINSTREL_VHT_GROUP_0 +                                         \
 75          MINSTREL_MAX_STREAMS * 2 * (_bw) +                             \
 76          MINSTREL_MAX_STREAMS * (_sgi) +                                \
 77          (_streams) - 1)
 78 
 79 #define BW2VBPS(_bw, r3, r2, r1)                                        \
 80         (_bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)
 81 
 82 #define VHT_GROUP(_streams, _sgi, _bw)                                  \
 83         [VHT_GROUP_IDX(_streams, _sgi, _bw)] = {                        \
 84         .streams = _streams,                                            \
 85         .flags =                                                        \
 86                 IEEE80211_TX_RC_VHT_MCS |                               \
 87                 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |                 \
 88                 (_bw == BW_80 ? IEEE80211_TX_RC_80_MHZ_WIDTH :          \
 89                  _bw == BW_40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),      \
 90         .duration = {                                                   \
 91                 MCS_DURATION(_streams, _sgi,                            \
 92                              BW2VBPS(_bw,  117,  54,  26)),             \
 93                 MCS_DURATION(_streams, _sgi,                            \
 94                              BW2VBPS(_bw,  234, 108,  52)),             \
 95                 MCS_DURATION(_streams, _sgi,                            \
 96                              BW2VBPS(_bw,  351, 162,  78)),             \
 97                 MCS_DURATION(_streams, _sgi,                            \
 98                              BW2VBPS(_bw,  468, 216, 104)),             \
 99                 MCS_DURATION(_streams, _sgi,                            \
100                              BW2VBPS(_bw,  702, 324, 156)),             \
101                 MCS_DURATION(_streams, _sgi,                            \
102                              BW2VBPS(_bw,  936, 432, 208)),             \
103                 MCS_DURATION(_streams, _sgi,                            \
104                              BW2VBPS(_bw, 1053, 486, 234)),             \
105                 MCS_DURATION(_streams, _sgi,                            \
106                              BW2VBPS(_bw, 1170, 540, 260)),             \
107                 MCS_DURATION(_streams, _sgi,                            \
108                              BW2VBPS(_bw, 1404, 648, 312)),             \
109                 MCS_DURATION(_streams, _sgi,                            \
110                              BW2VBPS(_bw, 1560, 720, 346))              \
111         }                                                               \
112 }
113 
114 #define CCK_DURATION(_bitrate, _short, _len)            \
115         (1000 * (10 /* SIFS */ +                        \
116          (_short ? 72 + 24 : 144 + 48) +                \
117          (8 * (_len + 4) * 10) / (_bitrate)))
118 
119 #define CCK_ACK_DURATION(_bitrate, _short)                      \
120         (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) +   \
121          CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))
122 
123 #define CCK_DURATION_LIST(_short)                       \
124         CCK_ACK_DURATION(10, _short),                   \
125         CCK_ACK_DURATION(20, _short),                   \
126         CCK_ACK_DURATION(55, _short),                   \
127         CCK_ACK_DURATION(110, _short)
128 
129 #define CCK_GROUP                                       \
130         [MINSTREL_CCK_GROUP] = {                        \
131                 .streams = 0,                           \
132                 .flags = 0,                             \
133                 .duration = {                           \
134                         CCK_DURATION_LIST(false),       \
135                         CCK_DURATION_LIST(true)         \
136                 }                                       \
137         }
138 
139 #ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
140 static bool minstrel_vht_only = true;
141 module_param(minstrel_vht_only, bool, 0644);
142 MODULE_PARM_DESC(minstrel_vht_only,
143                  "Use only VHT rates when VHT is supported by sta.");
144 #endif
145 
146 /*
147  * To enable sufficiently targeted rate sampling, MCS rates are divided into
148  * groups, based on the number of streams and flags (HT40, SGI) that they
149  * use.
150  *
151  * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
152  * BW -> SGI -> #streams
153  */
154 const struct mcs_group minstrel_mcs_groups[] = {
155         MCS_GROUP(1, 0, BW_20),
156         MCS_GROUP(2, 0, BW_20),
157 #if MINSTREL_MAX_STREAMS >= 3
158         MCS_GROUP(3, 0, BW_20),
159 #endif
160 
161         MCS_GROUP(1, 1, BW_20),
162         MCS_GROUP(2, 1, BW_20),
163 #if MINSTREL_MAX_STREAMS >= 3
164         MCS_GROUP(3, 1, BW_20),
165 #endif
166 
167         MCS_GROUP(1, 0, BW_40),
168         MCS_GROUP(2, 0, BW_40),
169 #if MINSTREL_MAX_STREAMS >= 3
170         MCS_GROUP(3, 0, BW_40),
171 #endif
172 
173         MCS_GROUP(1, 1, BW_40),
174         MCS_GROUP(2, 1, BW_40),
175 #if MINSTREL_MAX_STREAMS >= 3
176         MCS_GROUP(3, 1, BW_40),
177 #endif
178 
179         CCK_GROUP,
180 
181 #ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
182         VHT_GROUP(1, 0, BW_20),
183         VHT_GROUP(2, 0, BW_20),
184 #if MINSTREL_MAX_STREAMS >= 3
185         VHT_GROUP(3, 0, BW_20),
186 #endif
187 
188         VHT_GROUP(1, 1, BW_20),
189         VHT_GROUP(2, 1, BW_20),
190 #if MINSTREL_MAX_STREAMS >= 3
191         VHT_GROUP(3, 1, BW_20),
192 #endif
193 
194         VHT_GROUP(1, 0, BW_40),
195         VHT_GROUP(2, 0, BW_40),
196 #if MINSTREL_MAX_STREAMS >= 3
197         VHT_GROUP(3, 0, BW_40),
198 #endif
199 
200         VHT_GROUP(1, 1, BW_40),
201         VHT_GROUP(2, 1, BW_40),
202 #if MINSTREL_MAX_STREAMS >= 3
203         VHT_GROUP(3, 1, BW_40),
204 #endif
205 
206         VHT_GROUP(1, 0, BW_80),
207         VHT_GROUP(2, 0, BW_80),
208 #if MINSTREL_MAX_STREAMS >= 3
209         VHT_GROUP(3, 0, BW_80),
210 #endif
211 
212         VHT_GROUP(1, 1, BW_80),
213         VHT_GROUP(2, 1, BW_80),
214 #if MINSTREL_MAX_STREAMS >= 3
215         VHT_GROUP(3, 1, BW_80),
216 #endif
217 #endif
218 };
219 
220 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
221 
222 static void
223 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
224 
225 /*
226  * Some VHT MCSes are invalid (when Ndbps / Nes is not an integer)
227  * e.g for MCS9@20MHzx1Nss: Ndbps=8x52*(5/6) Nes=1
228  *
229  * Returns the valid mcs map for struct minstrel_mcs_group_data.supported
230  */
231 static u16
232 minstrel_get_valid_vht_rates(int bw, int nss, __le16 mcs_map)
233 {
234         u16 mask = 0;
235 
236         if (bw == BW_20) {
237                 if (nss != 3 && nss != 6)
238                         mask = BIT(9);
239         } else if (bw == BW_80) {
240                 if (nss == 3 || nss == 7)
241                         mask = BIT(6);
242                 else if (nss == 6)
243                         mask = BIT(9);
244         } else {
245                 WARN_ON(bw != BW_40);
246         }
247 
248         switch ((le16_to_cpu(mcs_map) >> (2 * (nss - 1))) & 3) {
249         case IEEE80211_VHT_MCS_SUPPORT_0_7:
250                 mask |= 0x300;
251                 break;
252         case IEEE80211_VHT_MCS_SUPPORT_0_8:
253                 mask |= 0x200;
254                 break;
255         case IEEE80211_VHT_MCS_SUPPORT_0_9:
256                 break;
257         default:
258                 mask = 0x3ff;
259         }
260 
261         return 0x3ff & ~mask;
262 }
263 
264 /*
265  * Look up an MCS group index based on mac80211 rate information
266  */
267 static int
268 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
269 {
270         return GROUP_IDX((rate->idx / 8) + 1,
271                          !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
272                          !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
273 }
274 
275 static int
276 minstrel_vht_get_group_idx(struct ieee80211_tx_rate *rate)
277 {
278         return VHT_GROUP_IDX(ieee80211_rate_get_vht_nss(rate),
279                              !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
280                              !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH) +
281                              2*!!(rate->flags & IEEE80211_TX_RC_80_MHZ_WIDTH));
282 }
283 
284 static struct minstrel_rate_stats *
285 minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
286                       struct ieee80211_tx_rate *rate)
287 {
288         int group, idx;
289 
290         if (rate->flags & IEEE80211_TX_RC_MCS) {
291                 group = minstrel_ht_get_group_idx(rate);
292                 idx = rate->idx % 8;
293         } else if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
294                 group = minstrel_vht_get_group_idx(rate);
295                 idx = ieee80211_rate_get_vht_mcs(rate);
296         } else {
297                 group = MINSTREL_CCK_GROUP;
298 
299                 for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++)
300                         if (rate->idx == mp->cck_rates[idx])
301                                 break;
302 
303                 /* short preamble */
304                 if (!(mi->groups[group].supported & BIT(idx)))
305                         idx += 4;
306         }
307         return &mi->groups[group].rates[idx];
308 }
309 
310 static inline struct minstrel_rate_stats *
311 minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
312 {
313         return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
314 }
315 
316 /*
317  * Return current throughput based on the average A-MPDU length, taking into
318  * account the expected number of retransmissions and their expected length
319  */
320 int
321 minstrel_ht_get_tp_avg(struct minstrel_ht_sta *mi, int group, int rate,
322                        int prob_ewma)
323 {
324         unsigned int nsecs = 0;
325 
326         /* do not account throughput if sucess prob is below 10% */
327         if (prob_ewma < MINSTREL_FRAC(10, 100))
328                 return 0;
329 
330         if (group != MINSTREL_CCK_GROUP)
331                 nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
332 
333         nsecs += minstrel_mcs_groups[group].duration[rate];
334 
335         /*
336          * For the throughput calculation, limit the probability value to 90% to
337          * account for collision related packet error rate fluctuation
338          * (prob is scaled - see MINSTREL_FRAC above)
339          */
340         if (prob_ewma > MINSTREL_FRAC(90, 100))
341                 return MINSTREL_TRUNC(100000 * ((MINSTREL_FRAC(90, 100) * 1000)
342                                                                       / nsecs));
343         else
344                 return MINSTREL_TRUNC(100000 * ((prob_ewma * 1000) / nsecs));
345 }
346 
347 /*
348  * Find & sort topmost throughput rates
349  *
350  * If multiple rates provide equal throughput the sorting is based on their
351  * current success probability. Higher success probability is preferred among
352  * MCS groups, CCK rates do not provide aggregation and are therefore at last.
353  */
354 static void
355 minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u16 index,
356                                u16 *tp_list)
357 {
358         int cur_group, cur_idx, cur_tp_avg, cur_prob;
359         int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
360         int j = MAX_THR_RATES;
361 
362         cur_group = index / MCS_GROUP_RATES;
363         cur_idx = index  % MCS_GROUP_RATES;
364         cur_prob = mi->groups[cur_group].rates[cur_idx].prob_ewma;
365         cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx, cur_prob);
366 
367         do {
368                 tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
369                 tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
370                 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
371                 tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx,
372                                                     tmp_prob);
373                 if (cur_tp_avg < tmp_tp_avg ||
374                     (cur_tp_avg == tmp_tp_avg && cur_prob <= tmp_prob))
375                         break;
376                 j--;
377         } while (j > 0);
378 
379         if (j < MAX_THR_RATES - 1) {
380                 memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) *
381                        (MAX_THR_RATES - (j + 1))));
382         }
383         if (j < MAX_THR_RATES)
384                 tp_list[j] = index;
385 }
386 
387 /*
388  * Find and set the topmost probability rate per sta and per group
389  */
390 static void
391 minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 index)
392 {
393         struct minstrel_mcs_group_data *mg;
394         struct minstrel_rate_stats *mrs;
395         int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
396         int max_tp_group, cur_tp_avg, cur_group, cur_idx;
397         int max_gpr_group, max_gpr_idx;
398         int max_gpr_tp_avg, max_gpr_prob;
399 
400         cur_group = index / MCS_GROUP_RATES;
401         cur_idx = index % MCS_GROUP_RATES;
402         mg = &mi->groups[index / MCS_GROUP_RATES];
403         mrs = &mg->rates[index % MCS_GROUP_RATES];
404 
405         tmp_group = mi->max_prob_rate / MCS_GROUP_RATES;
406         tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES;
407         tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
408         tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
409 
410         /* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
411          * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
412         max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES;
413         if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) &&
414             (max_tp_group != MINSTREL_CCK_GROUP))
415                 return;
416 
417         if (mrs->prob_ewma > MINSTREL_FRAC(75, 100)) {
418                 cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx,
419                                                     mrs->prob_ewma);
420                 if (cur_tp_avg > tmp_tp_avg)
421                         mi->max_prob_rate = index;
422 
423                 max_gpr_group = mg->max_group_prob_rate / MCS_GROUP_RATES;
424                 max_gpr_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
425                 max_gpr_prob = mi->groups[max_gpr_group].rates[max_gpr_idx].prob_ewma;
426                 max_gpr_tp_avg = minstrel_ht_get_tp_avg(mi, max_gpr_group,
427                                                         max_gpr_idx,
428                                                         max_gpr_prob);
429                 if (cur_tp_avg > max_gpr_tp_avg)
430                         mg->max_group_prob_rate = index;
431         } else {
432                 if (mrs->prob_ewma > tmp_prob)
433                         mi->max_prob_rate = index;
434                 if (mrs->prob_ewma > mg->rates[mg->max_group_prob_rate].prob_ewma)
435                         mg->max_group_prob_rate = index;
436         }
437 }
438 
439 
440 /*
441  * Assign new rate set per sta and use CCK rates only if the fastest
442  * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted
443  * rate sets where MCS and CCK rates are mixed, because CCK rates can
444  * not use aggregation.
445  */
446 static void
447 minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi,
448                                  u16 tmp_mcs_tp_rate[MAX_THR_RATES],
449                                  u16 tmp_cck_tp_rate[MAX_THR_RATES])
450 {
451         unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp, tmp_prob;
452         int i;
453 
454         tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES;
455         tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES;
456         tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
457         tmp_cck_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
458 
459         tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES;
460         tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES;
461         tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
462         tmp_mcs_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
463 
464         if (tmp_cck_tp > tmp_mcs_tp) {
465                 for(i = 0; i < MAX_THR_RATES; i++) {
466                         minstrel_ht_sort_best_tp_rates(mi, tmp_cck_tp_rate[i],
467                                                        tmp_mcs_tp_rate);
468                 }
469         }
470 
471 }
472 
473 /*
474  * Try to increase robustness of max_prob rate by decrease number of
475  * streams if possible.
476  */
477 static inline void
478 minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
479 {
480         struct minstrel_mcs_group_data *mg;
481         int tmp_max_streams, group, tmp_idx, tmp_prob;
482         int tmp_tp = 0;
483 
484         tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
485                           MCS_GROUP_RATES].streams;
486         for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
487                 mg = &mi->groups[group];
488                 if (!mg->supported || group == MINSTREL_CCK_GROUP)
489                         continue;
490 
491                 tmp_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
492                 tmp_prob = mi->groups[group].rates[tmp_idx].prob_ewma;
493 
494                 if (tmp_tp < minstrel_ht_get_tp_avg(mi, group, tmp_idx, tmp_prob) &&
495                    (minstrel_mcs_groups[group].streams < tmp_max_streams)) {
496                                 mi->max_prob_rate = mg->max_group_prob_rate;
497                                 tmp_tp = minstrel_ht_get_tp_avg(mi, group,
498                                                                 tmp_idx,
499                                                                 tmp_prob);
500                 }
501         }
502 }
503 
504 /*
505  * Update rate statistics and select new primary rates
506  *
507  * Rules for rate selection:
508  *  - max_prob_rate must use only one stream, as a tradeoff between delivery
509  *    probability and throughput during strong fluctuations
510  *  - as long as the max prob rate has a probability of more than 75%, pick
511  *    higher throughput rates, even if the probablity is a bit lower
512  */
513 static void
514 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
515 {
516         struct minstrel_mcs_group_data *mg;
517         struct minstrel_rate_stats *mrs;
518         int group, i, j, cur_prob;
519         u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
520         u16 tmp_cck_tp_rate[MAX_THR_RATES], index;
521 
522         if (mi->ampdu_packets > 0) {
523                 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
524                         MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
525                 mi->ampdu_len = 0;
526                 mi->ampdu_packets = 0;
527         }
528 
529         mi->sample_slow = 0;
530         mi->sample_count = 0;
531 
532         /* Initialize global rate indexes */
533         for(j = 0; j < MAX_THR_RATES; j++){
534                 tmp_mcs_tp_rate[j] = 0;
535                 tmp_cck_tp_rate[j] = 0;
536         }
537 
538         /* Find best rate sets within all MCS groups*/
539         for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
540 
541                 mg = &mi->groups[group];
542                 if (!mg->supported)
543                         continue;
544 
545                 mi->sample_count++;
546 
547                 /* (re)Initialize group rate indexes */
548                 for(j = 0; j < MAX_THR_RATES; j++)
549                         tmp_group_tp_rate[j] = group;
550 
551                 for (i = 0; i < MCS_GROUP_RATES; i++) {
552                         if (!(mg->supported & BIT(i)))
553                                 continue;
554 
555                         index = MCS_GROUP_RATES * group + i;
556 
557                         mrs = &mg->rates[i];
558                         mrs->retry_updated = false;
559                         minstrel_calc_rate_stats(mrs);
560                         cur_prob = mrs->prob_ewma;
561 
562                         if (minstrel_ht_get_tp_avg(mi, group, i, cur_prob) == 0)
563                                 continue;
564 
565                         /* Find max throughput rate set */
566                         if (group != MINSTREL_CCK_GROUP) {
567                                 minstrel_ht_sort_best_tp_rates(mi, index,
568                                                                tmp_mcs_tp_rate);
569                         } else if (group == MINSTREL_CCK_GROUP) {
570                                 minstrel_ht_sort_best_tp_rates(mi, index,
571                                                                tmp_cck_tp_rate);
572                         }
573 
574                         /* Find max throughput rate set within a group */
575                         minstrel_ht_sort_best_tp_rates(mi, index,
576                                                        tmp_group_tp_rate);
577 
578                         /* Find max probability rate per group and global */
579                         minstrel_ht_set_best_prob_rate(mi, index);
580                 }
581 
582                 memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
583                        sizeof(mg->max_group_tp_rate));
584         }
585 
586         /* Assign new rate set per sta */
587         minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate);
588         memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));
589 
590         /* Try to increase robustness of max_prob_rate*/
591         minstrel_ht_prob_rate_reduce_streams(mi);
592 
593         /* try to sample all available rates during each interval */
594         mi->sample_count *= 8;
595 
596 #ifdef CONFIG_MAC80211_DEBUGFS
597         /* use fixed index if set */
598         if (mp->fixed_rate_idx != -1) {
599                 for (i = 0; i < 4; i++)
600                         mi->max_tp_rate[i] = mp->fixed_rate_idx;
601                 mi->max_prob_rate = mp->fixed_rate_idx;
602         }
603 #endif
604 
605         /* Reset update timer */
606         mi->last_stats_update = jiffies;
607 }
608 
609 static bool
610 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
611 {
612         if (rate->idx < 0)
613                 return false;
614 
615         if (!rate->count)
616                 return false;
617 
618         if (rate->flags & IEEE80211_TX_RC_MCS ||
619             rate->flags & IEEE80211_TX_RC_VHT_MCS)
620                 return true;
621 
622         return rate->idx == mp->cck_rates[0] ||
623                rate->idx == mp->cck_rates[1] ||
624                rate->idx == mp->cck_rates[2] ||
625                rate->idx == mp->cck_rates[3];
626 }
627 
628 static void
629 minstrel_set_next_sample_idx(struct minstrel_ht_sta *mi)
630 {
631         struct minstrel_mcs_group_data *mg;
632 
633         for (;;) {
634                 mi->sample_group++;
635                 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
636                 mg = &mi->groups[mi->sample_group];
637 
638                 if (!mg->supported)
639                         continue;
640 
641                 if (++mg->index >= MCS_GROUP_RATES) {
642                         mg->index = 0;
643                         if (++mg->column >= ARRAY_SIZE(sample_table))
644                                 mg->column = 0;
645                 }
646                 break;
647         }
648 }
649 
650 static void
651 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u16 *idx, bool primary)
652 {
653         int group, orig_group;
654 
655         orig_group = group = *idx / MCS_GROUP_RATES;
656         while (group > 0) {
657                 group--;
658 
659                 if (!mi->groups[group].supported)
660                         continue;
661 
662                 if (minstrel_mcs_groups[group].streams >
663                     minstrel_mcs_groups[orig_group].streams)
664                         continue;
665 
666                 if (primary)
667                         *idx = mi->groups[group].max_group_tp_rate[0];
668                 else
669                         *idx = mi->groups[group].max_group_tp_rate[1];
670                 break;
671         }
672 }
673 
674 static void
675 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
676 {
677         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
678         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
679         u16 tid;
680 
681         if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
682                 return;
683 
684         if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
685                 return;
686 
687         if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
688                 return;
689 
690         tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
691         if (likely(sta->ampdu_mlme.tid_tx[tid]))
692                 return;
693 
694         ieee80211_start_tx_ba_session(pubsta, tid, 5000);
695 }
696 
697 static void
698 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
699                       struct ieee80211_sta *sta, void *priv_sta,
700                       struct ieee80211_tx_info *info)
701 {
702         struct minstrel_ht_sta_priv *msp = priv_sta;
703         struct minstrel_ht_sta *mi = &msp->ht;
704         struct ieee80211_tx_rate *ar = info->status.rates;
705         struct minstrel_rate_stats *rate, *rate2;
706         struct minstrel_priv *mp = priv;
707         bool last, update = false;
708         int i;
709 
710         if (!msp->is_ht)
711                 return mac80211_minstrel.tx_status_noskb(priv, sband, sta,
712                                                          &msp->legacy, info);
713 
714         /* This packet was aggregated but doesn't carry status info */
715         if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
716             !(info->flags & IEEE80211_TX_STAT_AMPDU))
717                 return;
718 
719         if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
720                 info->status.ampdu_ack_len =
721                         (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
722                 info->status.ampdu_len = 1;
723         }
724 
725         mi->ampdu_packets++;
726         mi->ampdu_len += info->status.ampdu_len;
727 
728         if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
729                 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
730                 mi->sample_tries = 1;
731                 mi->sample_count--;
732         }
733 
734         if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
735                 mi->sample_packets += info->status.ampdu_len;
736 
737         last = !minstrel_ht_txstat_valid(mp, &ar[0]);
738         for (i = 0; !last; i++) {
739                 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
740                        !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
741 
742                 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
743 
744                 if (last)
745                         rate->success += info->status.ampdu_ack_len;
746 
747                 rate->attempts += ar[i].count * info->status.ampdu_len;
748         }
749 
750         /*
751          * check for sudden death of spatial multiplexing,
752          * downgrade to a lower number of streams if necessary.
753          */
754         rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
755         if (rate->attempts > 30 &&
756             MINSTREL_FRAC(rate->success, rate->attempts) <
757             MINSTREL_FRAC(20, 100)) {
758                 minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
759                 update = true;
760         }
761 
762         rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
763         if (rate2->attempts > 30 &&
764             MINSTREL_FRAC(rate2->success, rate2->attempts) <
765             MINSTREL_FRAC(20, 100)) {
766                 minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
767                 update = true;
768         }
769 
770         if (time_after(jiffies, mi->last_stats_update +
771                                 (mp->update_interval / 2 * HZ) / 1000)) {
772                 update = true;
773                 minstrel_ht_update_stats(mp, mi);
774         }
775 
776         if (update)
777                 minstrel_ht_update_rates(mp, mi);
778 }
779 
780 static void
781 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
782                          int index)
783 {
784         struct minstrel_rate_stats *mrs;
785         const struct mcs_group *group;
786         unsigned int tx_time, tx_time_rtscts, tx_time_data;
787         unsigned int cw = mp->cw_min;
788         unsigned int ctime = 0;
789         unsigned int t_slot = 9; /* FIXME */
790         unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
791         unsigned int overhead = 0, overhead_rtscts = 0;
792 
793         mrs = minstrel_get_ratestats(mi, index);
794         if (mrs->prob_ewma < MINSTREL_FRAC(1, 10)) {
795                 mrs->retry_count = 1;
796                 mrs->retry_count_rtscts = 1;
797                 return;
798         }
799 
800         mrs->retry_count = 2;
801         mrs->retry_count_rtscts = 2;
802         mrs->retry_updated = true;
803 
804         group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
805         tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
806 
807         /* Contention time for first 2 tries */
808         ctime = (t_slot * cw) >> 1;
809         cw = min((cw << 1) | 1, mp->cw_max);
810         ctime += (t_slot * cw) >> 1;
811         cw = min((cw << 1) | 1, mp->cw_max);
812 
813         if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
814                 overhead = mi->overhead;
815                 overhead_rtscts = mi->overhead_rtscts;
816         }
817 
818         /* Total TX time for data and Contention after first 2 tries */
819         tx_time = ctime + 2 * (overhead + tx_time_data);
820         tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
821 
822         /* See how many more tries we can fit inside segment size */
823         do {
824                 /* Contention time for this try */
825                 ctime = (t_slot * cw) >> 1;
826                 cw = min((cw << 1) | 1, mp->cw_max);
827 
828                 /* Total TX time after this try */
829                 tx_time += ctime + overhead + tx_time_data;
830                 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
831 
832                 if (tx_time_rtscts < mp->segment_size)
833                         mrs->retry_count_rtscts++;
834         } while ((tx_time < mp->segment_size) &&
835                  (++mrs->retry_count < mp->max_retry));
836 }
837 
838 
839 static void
840 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
841                      struct ieee80211_sta_rates *ratetbl, int offset, int index)
842 {
843         const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
844         struct minstrel_rate_stats *mrs;
845         u8 idx;
846         u16 flags = group->flags;
847 
848         mrs = minstrel_get_ratestats(mi, index);
849         if (!mrs->retry_updated)
850                 minstrel_calc_retransmit(mp, mi, index);
851 
852         if (mrs->prob_ewma < MINSTREL_FRAC(20, 100) || !mrs->retry_count) {
853                 ratetbl->rate[offset].count = 2;
854                 ratetbl->rate[offset].count_rts = 2;
855                 ratetbl->rate[offset].count_cts = 2;
856         } else {
857                 ratetbl->rate[offset].count = mrs->retry_count;
858                 ratetbl->rate[offset].count_cts = mrs->retry_count;
859                 ratetbl->rate[offset].count_rts = mrs->retry_count_rtscts;
860         }
861 
862         if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP)
863                 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
864         else if (flags & IEEE80211_TX_RC_VHT_MCS)
865                 idx = ((group->streams - 1) << 4) |
866                       ((index % MCS_GROUP_RATES) & 0xF);
867         else
868                 idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;
869 
870         /* enable RTS/CTS if needed:
871          *  - if station is in dynamic SMPS (and streams > 1)
872          *  - for fallback rates, to increase chances of getting through
873          */
874         if (offset > 0 &&
875             (mi->sta->smps_mode == IEEE80211_SMPS_DYNAMIC &&
876              group->streams > 1)) {
877                 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
878                 flags |= IEEE80211_TX_RC_USE_RTS_CTS;
879         }
880 
881         ratetbl->rate[offset].idx = idx;
882         ratetbl->rate[offset].flags = flags;
883 }
884 
885 static void
886 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
887 {
888         struct ieee80211_sta_rates *rates;
889         int i = 0;
890 
891         rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
892         if (!rates)
893                 return;
894 
895         /* Start with max_tp_rate[0] */
896         minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
897 
898         if (mp->hw->max_rates >= 3) {
899                 /* At least 3 tx rates supported, use max_tp_rate[1] next */
900                 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]);
901         }
902 
903         if (mp->hw->max_rates >= 2) {
904                 /*
905                  * At least 2 tx rates supported, use max_prob_rate next */
906                 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
907         }
908 
909         rates->rate[i].idx = -1;
910         rate_control_set_rates(mp->hw, mi->sta, rates);
911 }
912 
913 static inline int
914 minstrel_get_duration(int index)
915 {
916         const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
917         return group->duration[index % MCS_GROUP_RATES];
918 }
919 
920 static int
921 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
922 {
923         struct minstrel_rate_stats *mrs;
924         struct minstrel_mcs_group_data *mg;
925         unsigned int sample_dur, sample_group, cur_max_tp_streams;
926         int sample_idx = 0;
927 
928         if (mi->sample_wait > 0) {
929                 mi->sample_wait--;
930                 return -1;
931         }
932 
933         if (!mi->sample_tries)
934                 return -1;
935 
936         sample_group = mi->sample_group;
937         mg = &mi->groups[sample_group];
938         sample_idx = sample_table[mg->column][mg->index];
939         minstrel_set_next_sample_idx(mi);
940 
941         if (!(mg->supported & BIT(sample_idx)))
942                 return -1;
943 
944         mrs = &mg->rates[sample_idx];
945         sample_idx += sample_group * MCS_GROUP_RATES;
946 
947         /*
948          * Sampling might add some overhead (RTS, no aggregation)
949          * to the frame. Hence, don't use sampling for the currently
950          * used rates.
951          */
952         if (sample_idx == mi->max_tp_rate[0] ||
953             sample_idx == mi->max_tp_rate[1] ||
954             sample_idx == mi->max_prob_rate)
955                 return -1;
956 
957         /*
958          * Do not sample if the probability is already higher than 95%
959          * to avoid wasting airtime.
960          */
961         if (mrs->prob_ewma > MINSTREL_FRAC(95, 100))
962                 return -1;
963 
964         /*
965          * Make sure that lower rates get sampled only occasionally,
966          * if the link is working perfectly.
967          */
968 
969         cur_max_tp_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
970                 MCS_GROUP_RATES].streams;
971         sample_dur = minstrel_get_duration(sample_idx);
972         if (sample_dur >= minstrel_get_duration(mi->max_tp_rate[1]) &&
973             (cur_max_tp_streams - 1 <
974              minstrel_mcs_groups[sample_group].streams ||
975              sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
976                 if (mrs->sample_skipped < 20)
977                         return -1;
978 
979                 if (mi->sample_slow++ > 2)
980                         return -1;
981         }
982         mi->sample_tries--;
983 
984         return sample_idx;
985 }
986 
987 static void
988 minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp,
989                                     struct minstrel_ht_sta *mi, bool val)
990 {
991         u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported;
992 
993         if (!supported || !mi->cck_supported_short)
994                 return;
995 
996         if (supported & (mi->cck_supported_short << (val * 4)))
997                 return;
998 
999         supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4);
1000         mi->groups[MINSTREL_CCK_GROUP].supported = supported;
1001 }
1002 
1003 static void
1004 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
1005                      struct ieee80211_tx_rate_control *txrc)
1006 {
1007         const struct mcs_group *sample_group;
1008         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
1009         struct ieee80211_tx_rate *rate = &info->status.rates[0];
1010         struct minstrel_ht_sta_priv *msp = priv_sta;
1011         struct minstrel_ht_sta *mi = &msp->ht;
1012         struct minstrel_priv *mp = priv;
1013         int sample_idx;
1014 
1015         if (rate_control_send_low(sta, priv_sta, txrc))
1016                 return;
1017 
1018         if (!msp->is_ht)
1019                 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
1020 
1021         if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
1022             mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
1023                 minstrel_aggr_check(sta, txrc->skb);
1024 
1025         info->flags |= mi->tx_flags;
1026         minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble);
1027 
1028 #ifdef CONFIG_MAC80211_DEBUGFS
1029         if (mp->fixed_rate_idx != -1)
1030                 return;
1031 #endif
1032 
1033         /* Don't use EAPOL frames for sampling on non-mrr hw */
1034         if (mp->hw->max_rates == 1 &&
1035             (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
1036                 sample_idx = -1;
1037         else
1038                 sample_idx = minstrel_get_sample_rate(mp, mi);
1039 
1040         mi->total_packets++;
1041 
1042         /* wraparound */
1043         if (mi->total_packets == ~0) {
1044                 mi->total_packets = 0;
1045                 mi->sample_packets = 0;
1046         }
1047 
1048         if (sample_idx < 0)
1049                 return;
1050 
1051         sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
1052         info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
1053         rate->count = 1;
1054 
1055         if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
1056                 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
1057                 rate->idx = mp->cck_rates[idx];
1058         } else if (sample_group->flags & IEEE80211_TX_RC_VHT_MCS) {
1059                 ieee80211_rate_set_vht(rate, sample_idx % MCS_GROUP_RATES,
1060                                        sample_group->streams);
1061         } else {
1062                 rate->idx = sample_idx % MCS_GROUP_RATES +
1063                             (sample_group->streams - 1) * 8;
1064         }
1065 
1066         rate->flags = sample_group->flags;
1067 }
1068 
1069 static void
1070 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1071                        struct ieee80211_supported_band *sband,
1072                        struct ieee80211_sta *sta)
1073 {
1074         int i;
1075 
1076         if (sband->band != IEEE80211_BAND_2GHZ)
1077                 return;
1078 
1079         if (!ieee80211_hw_check(mp->hw, SUPPORTS_HT_CCK_RATES))
1080                 return;
1081 
1082         mi->cck_supported = 0;
1083         mi->cck_supported_short = 0;
1084         for (i = 0; i < 4; i++) {
1085                 if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
1086                         continue;
1087 
1088                 mi->cck_supported |= BIT(i);
1089                 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
1090                         mi->cck_supported_short |= BIT(i);
1091         }
1092 
1093         mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported;
1094 }
1095 
1096 static void
1097 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
1098                         struct cfg80211_chan_def *chandef,
1099                         struct ieee80211_sta *sta, void *priv_sta)
1100 {
1101         struct minstrel_priv *mp = priv;
1102         struct minstrel_ht_sta_priv *msp = priv_sta;
1103         struct minstrel_ht_sta *mi = &msp->ht;
1104         struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
1105         u16 sta_cap = sta->ht_cap.cap;
1106         struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap;
1107         int use_vht;
1108         int n_supported = 0;
1109         int ack_dur;
1110         int stbc;
1111         int i;
1112 
1113         /* fall back to the old minstrel for legacy stations */
1114         if (!sta->ht_cap.ht_supported)
1115                 goto use_legacy;
1116 
1117         BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != MINSTREL_GROUPS_NB);
1118 
1119 #ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
1120         if (vht_cap->vht_supported)
1121                 use_vht = vht_cap->vht_mcs.tx_mcs_map != cpu_to_le16(~0);
1122         else
1123 #endif
1124         use_vht = 0;
1125 
1126         msp->is_ht = true;
1127         memset(mi, 0, sizeof(*mi));
1128 
1129         mi->sta = sta;
1130         mi->last_stats_update = jiffies;
1131 
1132         ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
1133         mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
1134         mi->overhead += ack_dur;
1135         mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
1136 
1137         mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
1138 
1139         /* When using MRR, sample more on the first attempt, without delay */
1140         if (mp->has_mrr) {
1141                 mi->sample_count = 16;
1142                 mi->sample_wait = 0;
1143         } else {
1144                 mi->sample_count = 8;
1145                 mi->sample_wait = 8;
1146         }
1147         mi->sample_tries = 4;
1148 
1149         /* TODO tx_flags for vht - ATM the RC API is not fine-grained enough */
1150         if (!use_vht) {
1151                 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
1152                         IEEE80211_HT_CAP_RX_STBC_SHIFT;
1153                 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
1154 
1155                 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
1156                         mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
1157         }
1158 
1159         for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
1160                 u32 gflags = minstrel_mcs_groups[i].flags;
1161                 int bw, nss;
1162 
1163                 mi->groups[i].supported = 0;
1164                 if (i == MINSTREL_CCK_GROUP) {
1165                         minstrel_ht_update_cck(mp, mi, sband, sta);
1166                         continue;
1167                 }
1168 
1169                 if (gflags & IEEE80211_TX_RC_SHORT_GI) {
1170                         if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
1171                                 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
1172                                         continue;
1173                         } else {
1174                                 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
1175                                         continue;
1176                         }
1177                 }
1178 
1179                 if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
1180                     sta->bandwidth < IEEE80211_STA_RX_BW_40)
1181                         continue;
1182 
1183                 nss = minstrel_mcs_groups[i].streams;
1184 
1185                 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
1186                 if (sta->smps_mode == IEEE80211_SMPS_STATIC && nss > 1)
1187                         continue;
1188 
1189                 /* HT rate */
1190                 if (gflags & IEEE80211_TX_RC_MCS) {
1191 #ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
1192                         if (use_vht && minstrel_vht_only)
1193                                 continue;
1194 #endif
1195                         mi->groups[i].supported = mcs->rx_mask[nss - 1];
1196                         if (mi->groups[i].supported)
1197                                 n_supported++;
1198                         continue;
1199                 }
1200 
1201                 /* VHT rate */
1202                 if (!vht_cap->vht_supported ||
1203                     WARN_ON(!(gflags & IEEE80211_TX_RC_VHT_MCS)) ||
1204                     WARN_ON(gflags & IEEE80211_TX_RC_160_MHZ_WIDTH))
1205                         continue;
1206 
1207                 if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH) {
1208                         if (sta->bandwidth < IEEE80211_STA_RX_BW_80 ||
1209                             ((gflags & IEEE80211_TX_RC_SHORT_GI) &&
1210                              !(vht_cap->cap & IEEE80211_VHT_CAP_SHORT_GI_80))) {
1211                                 continue;
1212                         }
1213                 }
1214 
1215                 if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH)
1216                         bw = BW_40;
1217                 else if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH)
1218                         bw = BW_80;
1219                 else
1220                         bw = BW_20;
1221 
1222                 mi->groups[i].supported = minstrel_get_valid_vht_rates(bw, nss,
1223                                 vht_cap->vht_mcs.tx_mcs_map);
1224 
1225                 if (mi->groups[i].supported)
1226                         n_supported++;
1227         }
1228 
1229         if (!n_supported)
1230                 goto use_legacy;
1231 
1232         /* create an initial rate table with the lowest supported rates */
1233         minstrel_ht_update_stats(mp, mi);
1234         minstrel_ht_update_rates(mp, mi);
1235 
1236         return;
1237 
1238 use_legacy:
1239         msp->is_ht = false;
1240         memset(&msp->legacy, 0, sizeof(msp->legacy));
1241         msp->legacy.r = msp->ratelist;
1242         msp->legacy.sample_table = msp->sample_table;
1243         return mac80211_minstrel.rate_init(priv, sband, chandef, sta,
1244                                            &msp->legacy);
1245 }
1246 
1247 static void
1248 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
1249                       struct cfg80211_chan_def *chandef,
1250                       struct ieee80211_sta *sta, void *priv_sta)
1251 {
1252         minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1253 }
1254 
1255 static void
1256 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
1257                         struct cfg80211_chan_def *chandef,
1258                         struct ieee80211_sta *sta, void *priv_sta,
1259                         u32 changed)
1260 {
1261         minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1262 }
1263 
1264 static void *
1265 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
1266 {
1267         struct ieee80211_supported_band *sband;
1268         struct minstrel_ht_sta_priv *msp;
1269         struct minstrel_priv *mp = priv;
1270         struct ieee80211_hw *hw = mp->hw;
1271         int max_rates = 0;
1272         int i;
1273 
1274         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1275                 sband = hw->wiphy->bands[i];
1276                 if (sband && sband->n_bitrates > max_rates)
1277                         max_rates = sband->n_bitrates;
1278         }
1279 
1280         msp = kzalloc(sizeof(*msp), gfp);
1281         if (!msp)
1282                 return NULL;
1283 
1284         msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
1285         if (!msp->ratelist)
1286                 goto error;
1287 
1288         msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
1289         if (!msp->sample_table)
1290                 goto error1;
1291 
1292         return msp;
1293 
1294 error1:
1295         kfree(msp->ratelist);
1296 error:
1297         kfree(msp);
1298         return NULL;
1299 }
1300 
1301 static void
1302 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1303 {
1304         struct minstrel_ht_sta_priv *msp = priv_sta;
1305 
1306         kfree(msp->sample_table);
1307         kfree(msp->ratelist);
1308         kfree(msp);
1309 }
1310 
1311 static void *
1312 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
1313 {
1314         return mac80211_minstrel.alloc(hw, debugfsdir);
1315 }
1316 
1317 static void
1318 minstrel_ht_free(void *priv)
1319 {
1320         mac80211_minstrel.free(priv);
1321 }
1322 
1323 static u32 minstrel_ht_get_expected_throughput(void *priv_sta)
1324 {
1325         struct minstrel_ht_sta_priv *msp = priv_sta;
1326         struct minstrel_ht_sta *mi = &msp->ht;
1327         int i, j, prob, tp_avg;
1328 
1329         if (!msp->is_ht)
1330                 return mac80211_minstrel.get_expected_throughput(priv_sta);
1331 
1332         i = mi->max_tp_rate[0] / MCS_GROUP_RATES;
1333         j = mi->max_tp_rate[0] % MCS_GROUP_RATES;
1334         prob = mi->groups[i].rates[j].prob_ewma;
1335 
1336         /* convert tp_avg from pkt per second in kbps */
1337         tp_avg = minstrel_ht_get_tp_avg(mi, i, j, prob) * AVG_PKT_SIZE * 8 / 1024;
1338 
1339         return tp_avg;
1340 }
1341 
1342 static const struct rate_control_ops mac80211_minstrel_ht = {
1343         .name = "minstrel_ht",
1344         .tx_status_noskb = minstrel_ht_tx_status,
1345         .get_rate = minstrel_ht_get_rate,
1346         .rate_init = minstrel_ht_rate_init,
1347         .rate_update = minstrel_ht_rate_update,
1348         .alloc_sta = minstrel_ht_alloc_sta,
1349         .free_sta = minstrel_ht_free_sta,
1350         .alloc = minstrel_ht_alloc,
1351         .free = minstrel_ht_free,
1352 #ifdef CONFIG_MAC80211_DEBUGFS
1353         .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
1354         .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
1355 #endif
1356         .get_expected_throughput = minstrel_ht_get_expected_throughput,
1357 };
1358 
1359 
1360 static void __init init_sample_table(void)
1361 {
1362         int col, i, new_idx;
1363         u8 rnd[MCS_GROUP_RATES];
1364 
1365         memset(sample_table, 0xff, sizeof(sample_table));
1366         for (col = 0; col < SAMPLE_COLUMNS; col++) {
1367                 prandom_bytes(rnd, sizeof(rnd));
1368                 for (i = 0; i < MCS_GROUP_RATES; i++) {
1369                         new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1370                         while (sample_table[col][new_idx] != 0xff)
1371                                 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1372 
1373                         sample_table[col][new_idx] = i;
1374                 }
1375         }
1376 }
1377 
1378 int __init
1379 rc80211_minstrel_ht_init(void)
1380 {
1381         init_sample_table();
1382         return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1383 }
1384 
1385 void
1386 rc80211_minstrel_ht_exit(void)
1387 {
1388         ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
1389 }
1390 

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