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Linux/net/mac80211/rc80211_minstrel_ht.c

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

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