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