1 /*
2 * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8 #include <linux/netdevice.h>
9 #include <linux/types.h>
10 #include <linux/skbuff.h>
11 #include <linux/debugfs.h>
12 #include <linux/random.h>
13 #include <linux/moduleparam.h>
14 #include <linux/ieee80211.h>
15 #include <net/mac80211.h>
16 #include "rate.h"
17 #include "sta_info.h"
18 #include "rc80211_minstrel.h"
19 #include "rc80211_minstrel_ht.h"
20
21 #define AVG_AMPDU_SIZE 16
22 #define AVG_PKT_SIZE 1200
23
24 /* Number of bits for an average sized packet */
25 #define MCS_NBITS ((AVG_PKT_SIZE * AVG_AMPDU_SIZE) << 3)
26
27 /* Number of symbols for a packet with (bps) bits per symbol */
28 #define MCS_NSYMS(bps) DIV_ROUND_UP(MCS_NBITS, (bps))
29
30 /* Transmission time (nanoseconds) for a packet containing (syms) symbols */
31 #define MCS_SYMBOL_TIME(sgi, syms) \
32 (sgi ? \
33 ((syms) * 18000 + 4000) / 5 : /* syms * 3.6 us */ \
34 ((syms) * 1000) << 2 /* syms * 4 us */ \
35 )
36
37 /* Transmit duration for the raw data part of an average sized packet */
38 #define MCS_DURATION(streams, sgi, bps) \
39 (MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps))) / AVG_AMPDU_SIZE)
40
41 #define BW_20 0
42 #define BW_40 1
43 #define BW_80 2
44
45 /*
46 * Define group sort order: HT40 -> SGI -> #streams
47 */
48 #define GROUP_IDX(_streams, _sgi, _ht40) \
49 MINSTREL_HT_GROUP_0 + \
50 MINSTREL_MAX_STREAMS * 2 * _ht40 + \
51 MINSTREL_MAX_STREAMS * _sgi + \
52 _streams - 1
53
54 /* MCS rate information for an MCS group */
55 #define MCS_GROUP(_streams, _sgi, _ht40) \
56 [GROUP_IDX(_streams, _sgi, _ht40)] = { \
57 .streams = _streams, \
58 .flags = \
59 IEEE80211_TX_RC_MCS | \
60 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
61 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
62 .duration = { \
63 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \
64 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \
65 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \
66 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \
67 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \
68 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \
69 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \
70 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \
71 } \
72 }
73
74 #define VHT_GROUP_IDX(_streams, _sgi, _bw) \
75 (MINSTREL_VHT_GROUP_0 + \
76 MINSTREL_MAX_STREAMS * 2 * (_bw) + \
77 MINSTREL_MAX_STREAMS * (_sgi) + \
78 (_streams) - 1)
79
80 #define BW2VBPS(_bw, r3, r2, r1) \
81 (_bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)
82
83 #define VHT_GROUP(_streams, _sgi, _bw) \
84 [VHT_GROUP_IDX(_streams, _sgi, _bw)] = { \
85 .streams = _streams, \
86 .flags = \
87 IEEE80211_TX_RC_VHT_MCS | \
88 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
89 (_bw == BW_80 ? IEEE80211_TX_RC_80_MHZ_WIDTH : \
90 _bw == BW_40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
91 .duration = { \
92 MCS_DURATION(_streams, _sgi, \
93 BW2VBPS(_bw, 117, 54, 26)), \
94 MCS_DURATION(_streams, _sgi, \
95 BW2VBPS(_bw, 234, 108, 52)), \
96 MCS_DURATION(_streams, _sgi, \
97 BW2VBPS(_bw, 351, 162, 78)), \
98 MCS_DURATION(_streams, _sgi, \
99 BW2VBPS(_bw, 468, 216, 104)), \
100 MCS_DURATION(_streams, _sgi, \
101 BW2VBPS(_bw, 702, 324, 156)), \
102 MCS_DURATION(_streams, _sgi, \
103 BW2VBPS(_bw, 936, 432, 208)), \
104 MCS_DURATION(_streams, _sgi, \
105 BW2VBPS(_bw, 1053, 486, 234)), \
106 MCS_DURATION(_streams, _sgi, \
107 BW2VBPS(_bw, 1170, 540, 260)), \
108 MCS_DURATION(_streams, _sgi, \
109 BW2VBPS(_bw, 1404, 648, 312)), \
110 MCS_DURATION(_streams, _sgi, \
111 BW2VBPS(_bw, 1560, 720, 346)) \
112 } \
113 }
114
115 #define CCK_DURATION(_bitrate, _short, _len) \
116 (1000 * (10 /* SIFS */ + \
117 (_short ? 72 + 24 : 144 + 48) + \
118 (8 * (_len + 4) * 10) / (_bitrate)))
119
120 #define CCK_ACK_DURATION(_bitrate, _short) \
121 (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) + \
122 CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))
123
124 #define CCK_DURATION_LIST(_short) \
125 CCK_ACK_DURATION(10, _short), \
126 CCK_ACK_DURATION(20, _short), \
127 CCK_ACK_DURATION(55, _short), \
128 CCK_ACK_DURATION(110, _short)
129
130 #define CCK_GROUP \
131 [MINSTREL_CCK_GROUP] = { \
132 .streams = 1, \
133 .flags = 0, \
134 .duration = { \
135 CCK_DURATION_LIST(false), \
136 CCK_DURATION_LIST(true) \
137 } \
138 }
139
140 #ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
141 static bool minstrel_vht_only = true;
142 module_param(minstrel_vht_only, bool, 0644);
143 MODULE_PARM_DESC(minstrel_vht_only,
144 "Use only VHT rates when VHT is supported by sta.");
145 #endif
146
147 /*
148 * To enable sufficiently targeted rate sampling, MCS rates are divided into
149 * groups, based on the number of streams and flags (HT40, SGI) that they
150 * use.
151 *
152 * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
153 * BW -> SGI -> #streams
154 */
155 const struct mcs_group minstrel_mcs_groups[] = {
156 MCS_GROUP(1, 0, BW_20),
157 MCS_GROUP(2, 0, BW_20),
158 MCS_GROUP(3, 0, BW_20),
159
160 MCS_GROUP(1, 1, BW_20),
161 MCS_GROUP(2, 1, BW_20),
162 MCS_GROUP(3, 1, BW_20),
163
164 MCS_GROUP(1, 0, BW_40),
165 MCS_GROUP(2, 0, BW_40),
166 MCS_GROUP(3, 0, BW_40),
167
168 MCS_GROUP(1, 1, BW_40),
169 MCS_GROUP(2, 1, BW_40),
170 MCS_GROUP(3, 1, BW_40),
171
172 CCK_GROUP,
173
174 #ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
175 VHT_GROUP(1, 0, BW_20),
176 VHT_GROUP(2, 0, BW_20),
177 VHT_GROUP(3, 0, BW_20),
178
179 VHT_GROUP(1, 1, BW_20),
180 VHT_GROUP(2, 1, BW_20),
181 VHT_GROUP(3, 1, BW_20),
182
183 VHT_GROUP(1, 0, BW_40),
184 VHT_GROUP(2, 0, BW_40),
185 VHT_GROUP(3, 0, BW_40),
186
187 VHT_GROUP(1, 1, BW_40),
188 VHT_GROUP(2, 1, BW_40),
189 VHT_GROUP(3, 1, BW_40),
190
191 VHT_GROUP(1, 0, BW_80),
192 VHT_GROUP(2, 0, BW_80),
193 VHT_GROUP(3, 0, BW_80),
194
195 VHT_GROUP(1, 1, BW_80),
196 VHT_GROUP(2, 1, BW_80),
197 VHT_GROUP(3, 1, BW_80),
198 #endif
199 };
200
201 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
202
203 static void
204 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
205
206 /*
207 * Some VHT MCSes are invalid (when Ndbps / Nes is not an integer)
208 * e.g for MCS9@20MHzx1Nss: Ndbps=8x52*(5/6) Nes=1
209 *
210 * Returns the valid mcs map for struct minstrel_mcs_group_data.supported
211 */
212 static u16
minstrel_get_valid_vht_rates(int bw,int nss,__le16 mcs_map)213 minstrel_get_valid_vht_rates(int bw, int nss, __le16 mcs_map)
214 {
215 u16 mask = 0;
216
217 if (bw == BW_20) {
218 if (nss != 3 && nss != 6)
219 mask = BIT(9);
220 } else if (bw == BW_80) {
221 if (nss == 3 || nss == 7)
222 mask = BIT(6);
223 else if (nss == 6)
224 mask = BIT(9);
225 } else {
226 WARN_ON(bw != BW_40);
227 }
228
229 switch ((le16_to_cpu(mcs_map) >> (2 * (nss - 1))) & 3) {
230 case IEEE80211_VHT_MCS_SUPPORT_0_7:
231 mask |= 0x300;
232 break;
233 case IEEE80211_VHT_MCS_SUPPORT_0_8:
234 mask |= 0x200;
235 break;
236 case IEEE80211_VHT_MCS_SUPPORT_0_9:
237 break;
238 default:
239 mask = 0x3ff;
240 }
241
242 return 0x3ff & ~mask;
243 }
244
245 /*
246 * Look up an MCS group index based on mac80211 rate information
247 */
248 static int
minstrel_ht_get_group_idx(struct ieee80211_tx_rate * rate)249 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
250 {
251 return GROUP_IDX((rate->idx / 8) + 1,
252 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
253 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
254 }
255
256 static int
minstrel_vht_get_group_idx(struct ieee80211_tx_rate * rate)257 minstrel_vht_get_group_idx(struct ieee80211_tx_rate *rate)
258 {
259 return VHT_GROUP_IDX(ieee80211_rate_get_vht_nss(rate),
260 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
261 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH) +
262 2*!!(rate->flags & IEEE80211_TX_RC_80_MHZ_WIDTH));
263 }
264
265 static struct minstrel_rate_stats *
minstrel_ht_get_stats(struct minstrel_priv * mp,struct minstrel_ht_sta * mi,struct ieee80211_tx_rate * rate)266 minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
267 struct ieee80211_tx_rate *rate)
268 {
269 int group, idx;
270
271 if (rate->flags & IEEE80211_TX_RC_MCS) {
272 group = minstrel_ht_get_group_idx(rate);
273 idx = rate->idx % 8;
274 } else if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
275 group = minstrel_vht_get_group_idx(rate);
276 idx = ieee80211_rate_get_vht_mcs(rate);
277 } else {
278 group = MINSTREL_CCK_GROUP;
279
280 for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++)
281 if (rate->idx == mp->cck_rates[idx])
282 break;
283
284 /* short preamble */
285 if ((mi->supported[group] & BIT(idx + 4)) &&
286 (rate->flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE))
287 idx += 4;
288 }
289 return &mi->groups[group].rates[idx];
290 }
291
292 static inline struct minstrel_rate_stats *
minstrel_get_ratestats(struct minstrel_ht_sta * mi,int index)293 minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
294 {
295 return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
296 }
297
298 /*
299 * Return current throughput based on the average A-MPDU length, taking into
300 * account the expected number of retransmissions and their expected length
301 */
302 int
minstrel_ht_get_tp_avg(struct minstrel_ht_sta * mi,int group,int rate,int prob_ewma)303 minstrel_ht_get_tp_avg(struct minstrel_ht_sta *mi, int group, int rate,
304 int prob_ewma)
305 {
306 unsigned int nsecs = 0;
307
308 /* do not account throughput if sucess prob is below 10% */
309 if (prob_ewma < MINSTREL_FRAC(10, 100))
310 return 0;
311
312 if (group != MINSTREL_CCK_GROUP)
313 nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
314
315 nsecs += minstrel_mcs_groups[group].duration[rate];
316
317 /*
318 * For the throughput calculation, limit the probability value to 90% to
319 * account for collision related packet error rate fluctuation
320 * (prob is scaled - see MINSTREL_FRAC above)
321 */
322 if (prob_ewma > MINSTREL_FRAC(90, 100))
323 return MINSTREL_TRUNC(100000 * ((MINSTREL_FRAC(90, 100) * 1000)
324 / nsecs));
325 else
326 return MINSTREL_TRUNC(100000 * ((prob_ewma * 1000) / nsecs));
327 }
328
329 /*
330 * Find & sort topmost throughput rates
331 *
332 * If multiple rates provide equal throughput the sorting is based on their
333 * current success probability. Higher success probability is preferred among
334 * MCS groups, CCK rates do not provide aggregation and are therefore at last.
335 */
336 static void
minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta * mi,u16 index,u16 * tp_list)337 minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u16 index,
338 u16 *tp_list)
339 {
340 int cur_group, cur_idx, cur_tp_avg, cur_prob;
341 int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
342 int j = MAX_THR_RATES;
343
344 cur_group = index / MCS_GROUP_RATES;
345 cur_idx = index % MCS_GROUP_RATES;
346 cur_prob = mi->groups[cur_group].rates[cur_idx].prob_ewma;
347 cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx, cur_prob);
348
349 do {
350 tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
351 tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
352 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
353 tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx,
354 tmp_prob);
355 if (cur_tp_avg < tmp_tp_avg ||
356 (cur_tp_avg == tmp_tp_avg && cur_prob <= tmp_prob))
357 break;
358 j--;
359 } while (j > 0);
360
361 if (j < MAX_THR_RATES - 1) {
362 memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) *
363 (MAX_THR_RATES - (j + 1))));
364 }
365 if (j < MAX_THR_RATES)
366 tp_list[j] = index;
367 }
368
369 /*
370 * Find and set the topmost probability rate per sta and per group
371 */
372 static void
minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta * mi,u16 index)373 minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 index)
374 {
375 struct minstrel_mcs_group_data *mg;
376 struct minstrel_rate_stats *mrs;
377 int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
378 int max_tp_group, cur_tp_avg, cur_group, cur_idx;
379 int max_gpr_group, max_gpr_idx;
380 int max_gpr_tp_avg, max_gpr_prob;
381
382 cur_group = index / MCS_GROUP_RATES;
383 cur_idx = index % MCS_GROUP_RATES;
384 mg = &mi->groups[index / MCS_GROUP_RATES];
385 mrs = &mg->rates[index % MCS_GROUP_RATES];
386
387 tmp_group = mi->max_prob_rate / MCS_GROUP_RATES;
388 tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES;
389 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
390 tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
391
392 /* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
393 * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
394 max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES;
395 if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) &&
396 (max_tp_group != MINSTREL_CCK_GROUP))
397 return;
398
399 max_gpr_group = mg->max_group_prob_rate / MCS_GROUP_RATES;
400 max_gpr_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
401 max_gpr_prob = mi->groups[max_gpr_group].rates[max_gpr_idx].prob_ewma;
402
403 if (mrs->prob_ewma > MINSTREL_FRAC(75, 100)) {
404 cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx,
405 mrs->prob_ewma);
406 if (cur_tp_avg > tmp_tp_avg)
407 mi->max_prob_rate = index;
408
409 max_gpr_tp_avg = minstrel_ht_get_tp_avg(mi, max_gpr_group,
410 max_gpr_idx,
411 max_gpr_prob);
412 if (cur_tp_avg > max_gpr_tp_avg)
413 mg->max_group_prob_rate = index;
414 } else {
415 if (mrs->prob_ewma > tmp_prob)
416 mi->max_prob_rate = index;
417 if (mrs->prob_ewma > max_gpr_prob)
418 mg->max_group_prob_rate = index;
419 }
420 }
421
422
423 /*
424 * Assign new rate set per sta and use CCK rates only if the fastest
425 * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted
426 * rate sets where MCS and CCK rates are mixed, because CCK rates can
427 * not use aggregation.
428 */
429 static void
minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta * mi,u16 tmp_mcs_tp_rate[MAX_THR_RATES],u16 tmp_cck_tp_rate[MAX_THR_RATES])430 minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi,
431 u16 tmp_mcs_tp_rate[MAX_THR_RATES],
432 u16 tmp_cck_tp_rate[MAX_THR_RATES])
433 {
434 unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp, tmp_prob;
435 int i;
436
437 tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES;
438 tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES;
439 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
440 tmp_cck_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
441
442 tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES;
443 tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES;
444 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
445 tmp_mcs_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
446
447 if (tmp_cck_tp > tmp_mcs_tp) {
448 for(i = 0; i < MAX_THR_RATES; i++) {
449 minstrel_ht_sort_best_tp_rates(mi, tmp_cck_tp_rate[i],
450 tmp_mcs_tp_rate);
451 }
452 }
453
454 }
455
456 /*
457 * Try to increase robustness of max_prob rate by decrease number of
458 * streams if possible.
459 */
460 static inline void
minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta * mi)461 minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
462 {
463 struct minstrel_mcs_group_data *mg;
464 int tmp_max_streams, group, tmp_idx, tmp_prob;
465 int tmp_tp = 0;
466
467 tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
468 MCS_GROUP_RATES].streams;
469 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
470 mg = &mi->groups[group];
471 if (!mi->supported[group] || group == MINSTREL_CCK_GROUP)
472 continue;
473
474 tmp_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
475 tmp_prob = mi->groups[group].rates[tmp_idx].prob_ewma;
476
477 if (tmp_tp < minstrel_ht_get_tp_avg(mi, group, tmp_idx, tmp_prob) &&
478 (minstrel_mcs_groups[group].streams < tmp_max_streams)) {
479 mi->max_prob_rate = mg->max_group_prob_rate;
480 tmp_tp = minstrel_ht_get_tp_avg(mi, group,
481 tmp_idx,
482 tmp_prob);
483 }
484 }
485 }
486
487 /*
488 * Update rate statistics and select new primary rates
489 *
490 * Rules for rate selection:
491 * - max_prob_rate must use only one stream, as a tradeoff between delivery
492 * probability and throughput during strong fluctuations
493 * - as long as the max prob rate has a probability of more than 75%, pick
494 * higher throughput rates, even if the probablity is a bit lower
495 */
496 static void
minstrel_ht_update_stats(struct minstrel_priv * mp,struct minstrel_ht_sta * mi)497 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
498 {
499 struct minstrel_mcs_group_data *mg;
500 struct minstrel_rate_stats *mrs;
501 int group, i, j, cur_prob;
502 u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
503 u16 tmp_cck_tp_rate[MAX_THR_RATES], index;
504
505 if (mi->ampdu_packets > 0) {
506 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
507 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
508 mi->ampdu_len = 0;
509 mi->ampdu_packets = 0;
510 }
511
512 mi->sample_slow = 0;
513 mi->sample_count = 0;
514
515 /* Initialize global rate indexes */
516 for(j = 0; j < MAX_THR_RATES; j++){
517 tmp_mcs_tp_rate[j] = 0;
518 tmp_cck_tp_rate[j] = 0;
519 }
520
521 /* Find best rate sets within all MCS groups*/
522 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
523
524 mg = &mi->groups[group];
525 if (!mi->supported[group])
526 continue;
527
528 mi->sample_count++;
529
530 /* (re)Initialize group rate indexes */
531 for(j = 0; j < MAX_THR_RATES; j++)
532 tmp_group_tp_rate[j] = MCS_GROUP_RATES * group;
533
534 for (i = 0; i < MCS_GROUP_RATES; i++) {
535 if (!(mi->supported[group] & BIT(i)))
536 continue;
537
538 index = MCS_GROUP_RATES * group + i;
539
540 mrs = &mg->rates[i];
541 mrs->retry_updated = false;
542 minstrel_calc_rate_stats(mrs);
543 cur_prob = mrs->prob_ewma;
544
545 if (minstrel_ht_get_tp_avg(mi, group, i, cur_prob) == 0)
546 continue;
547
548 /* Find max throughput rate set */
549 if (group != MINSTREL_CCK_GROUP) {
550 minstrel_ht_sort_best_tp_rates(mi, index,
551 tmp_mcs_tp_rate);
552 } else if (group == MINSTREL_CCK_GROUP) {
553 minstrel_ht_sort_best_tp_rates(mi, index,
554 tmp_cck_tp_rate);
555 }
556
557 /* Find max throughput rate set within a group */
558 minstrel_ht_sort_best_tp_rates(mi, index,
559 tmp_group_tp_rate);
560
561 /* Find max probability rate per group and global */
562 minstrel_ht_set_best_prob_rate(mi, index);
563 }
564
565 memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
566 sizeof(mg->max_group_tp_rate));
567 }
568
569 /* Assign new rate set per sta */
570 minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate);
571 memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));
572
573 /* Try to increase robustness of max_prob_rate*/
574 minstrel_ht_prob_rate_reduce_streams(mi);
575
576 /* try to sample all available rates during each interval */
577 mi->sample_count *= 8;
578
579 #ifdef CONFIG_MAC80211_DEBUGFS
580 /* use fixed index if set */
581 if (mp->fixed_rate_idx != -1) {
582 for (i = 0; i < 4; i++)
583 mi->max_tp_rate[i] = mp->fixed_rate_idx;
584 mi->max_prob_rate = mp->fixed_rate_idx;
585 }
586 #endif
587
588 /* Reset update timer */
589 mi->last_stats_update = jiffies;
590 }
591
592 static bool
minstrel_ht_txstat_valid(struct minstrel_priv * mp,struct ieee80211_tx_rate * rate)593 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
594 {
595 if (rate->idx < 0)
596 return false;
597
598 if (!rate->count)
599 return false;
600
601 if (rate->flags & IEEE80211_TX_RC_MCS ||
602 rate->flags & IEEE80211_TX_RC_VHT_MCS)
603 return true;
604
605 return rate->idx == mp->cck_rates[0] ||
606 rate->idx == mp->cck_rates[1] ||
607 rate->idx == mp->cck_rates[2] ||
608 rate->idx == mp->cck_rates[3];
609 }
610
611 static void
minstrel_set_next_sample_idx(struct minstrel_ht_sta * mi)612 minstrel_set_next_sample_idx(struct minstrel_ht_sta *mi)
613 {
614 struct minstrel_mcs_group_data *mg;
615
616 for (;;) {
617 mi->sample_group++;
618 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
619 mg = &mi->groups[mi->sample_group];
620
621 if (!mi->supported[mi->sample_group])
622 continue;
623
624 if (++mg->index >= MCS_GROUP_RATES) {
625 mg->index = 0;
626 if (++mg->column >= ARRAY_SIZE(sample_table))
627 mg->column = 0;
628 }
629 break;
630 }
631 }
632
633 static void
minstrel_downgrade_rate(struct minstrel_ht_sta * mi,u16 * idx,bool primary)634 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u16 *idx, bool primary)
635 {
636 int group, orig_group;
637
638 orig_group = group = *idx / MCS_GROUP_RATES;
639 while (group > 0) {
640 group--;
641
642 if (!mi->supported[group])
643 continue;
644
645 if (minstrel_mcs_groups[group].streams >
646 minstrel_mcs_groups[orig_group].streams)
647 continue;
648
649 if (primary)
650 *idx = mi->groups[group].max_group_tp_rate[0];
651 else
652 *idx = mi->groups[group].max_group_tp_rate[1];
653 break;
654 }
655 }
656
657 static void
minstrel_aggr_check(struct ieee80211_sta * pubsta,struct sk_buff * skb)658 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
659 {
660 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
661 struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
662 u16 tid;
663
664 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
665 return;
666
667 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
668 return;
669
670 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
671 return;
672
673 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
674 if (likely(sta->ampdu_mlme.tid_tx[tid]))
675 return;
676
677 ieee80211_start_tx_ba_session(pubsta, tid, 0);
678 }
679
680 static void
minstrel_ht_tx_status(void * priv,struct ieee80211_supported_band * sband,void * priv_sta,struct ieee80211_tx_status * st)681 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
682 void *priv_sta, struct ieee80211_tx_status *st)
683 {
684 struct ieee80211_tx_info *info = st->info;
685 struct minstrel_ht_sta_priv *msp = priv_sta;
686 struct minstrel_ht_sta *mi = &msp->ht;
687 struct ieee80211_tx_rate *ar = info->status.rates;
688 struct minstrel_rate_stats *rate, *rate2;
689 struct minstrel_priv *mp = priv;
690 bool last, update = false;
691 int i;
692
693 if (!msp->is_ht)
694 return mac80211_minstrel.tx_status_ext(priv, sband,
695 &msp->legacy, st);
696
697 /* This packet was aggregated but doesn't carry status info */
698 if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
699 !(info->flags & IEEE80211_TX_STAT_AMPDU))
700 return;
701
702 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
703 info->status.ampdu_ack_len =
704 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
705 info->status.ampdu_len = 1;
706 }
707
708 mi->ampdu_packets++;
709 mi->ampdu_len += info->status.ampdu_len;
710
711 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
712 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
713 mi->sample_tries = 1;
714 mi->sample_count--;
715 }
716
717 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
718 mi->sample_packets += info->status.ampdu_len;
719
720 last = !minstrel_ht_txstat_valid(mp, &ar[0]);
721 for (i = 0; !last; i++) {
722 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
723 !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
724
725 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
726
727 if (last)
728 rate->success += info->status.ampdu_ack_len;
729
730 rate->attempts += ar[i].count * info->status.ampdu_len;
731 }
732
733 /*
734 * check for sudden death of spatial multiplexing,
735 * downgrade to a lower number of streams if necessary.
736 */
737 rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
738 if (rate->attempts > 30 &&
739 MINSTREL_FRAC(rate->success, rate->attempts) <
740 MINSTREL_FRAC(20, 100)) {
741 minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
742 update = true;
743 }
744
745 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
746 if (rate2->attempts > 30 &&
747 MINSTREL_FRAC(rate2->success, rate2->attempts) <
748 MINSTREL_FRAC(20, 100)) {
749 minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
750 update = true;
751 }
752
753 if (time_after(jiffies, mi->last_stats_update +
754 (mp->update_interval / 2 * HZ) / 1000)) {
755 update = true;
756 minstrel_ht_update_stats(mp, mi);
757 }
758
759 if (update)
760 minstrel_ht_update_rates(mp, mi);
761 }
762
763 static void
minstrel_calc_retransmit(struct minstrel_priv * mp,struct minstrel_ht_sta * mi,int index)764 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
765 int index)
766 {
767 struct minstrel_rate_stats *mrs;
768 const struct mcs_group *group;
769 unsigned int tx_time, tx_time_rtscts, tx_time_data;
770 unsigned int cw = mp->cw_min;
771 unsigned int ctime = 0;
772 unsigned int t_slot = 9; /* FIXME */
773 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
774 unsigned int overhead = 0, overhead_rtscts = 0;
775
776 mrs = minstrel_get_ratestats(mi, index);
777 if (mrs->prob_ewma < MINSTREL_FRAC(1, 10)) {
778 mrs->retry_count = 1;
779 mrs->retry_count_rtscts = 1;
780 return;
781 }
782
783 mrs->retry_count = 2;
784 mrs->retry_count_rtscts = 2;
785 mrs->retry_updated = true;
786
787 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
788 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
789
790 /* Contention time for first 2 tries */
791 ctime = (t_slot * cw) >> 1;
792 cw = min((cw << 1) | 1, mp->cw_max);
793 ctime += (t_slot * cw) >> 1;
794 cw = min((cw << 1) | 1, mp->cw_max);
795
796 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
797 overhead = mi->overhead;
798 overhead_rtscts = mi->overhead_rtscts;
799 }
800
801 /* Total TX time for data and Contention after first 2 tries */
802 tx_time = ctime + 2 * (overhead + tx_time_data);
803 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
804
805 /* See how many more tries we can fit inside segment size */
806 do {
807 /* Contention time for this try */
808 ctime = (t_slot * cw) >> 1;
809 cw = min((cw << 1) | 1, mp->cw_max);
810
811 /* Total TX time after this try */
812 tx_time += ctime + overhead + tx_time_data;
813 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
814
815 if (tx_time_rtscts < mp->segment_size)
816 mrs->retry_count_rtscts++;
817 } while ((tx_time < mp->segment_size) &&
818 (++mrs->retry_count < mp->max_retry));
819 }
820
821
822 static void
minstrel_ht_set_rate(struct minstrel_priv * mp,struct minstrel_ht_sta * mi,struct ieee80211_sta_rates * ratetbl,int offset,int index)823 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
824 struct ieee80211_sta_rates *ratetbl, int offset, int index)
825 {
826 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
827 struct minstrel_rate_stats *mrs;
828 u8 idx;
829 u16 flags = group->flags;
830
831 mrs = minstrel_get_ratestats(mi, index);
832 if (!mrs->retry_updated)
833 minstrel_calc_retransmit(mp, mi, index);
834
835 if (mrs->prob_ewma < MINSTREL_FRAC(20, 100) || !mrs->retry_count) {
836 ratetbl->rate[offset].count = 2;
837 ratetbl->rate[offset].count_rts = 2;
838 ratetbl->rate[offset].count_cts = 2;
839 } else {
840 ratetbl->rate[offset].count = mrs->retry_count;
841 ratetbl->rate[offset].count_cts = mrs->retry_count;
842 ratetbl->rate[offset].count_rts = mrs->retry_count_rtscts;
843 }
844
845 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP)
846 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
847 else if (flags & IEEE80211_TX_RC_VHT_MCS)
848 idx = ((group->streams - 1) << 4) |
849 ((index % MCS_GROUP_RATES) & 0xF);
850 else
851 idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;
852
853 /* enable RTS/CTS if needed:
854 * - if station is in dynamic SMPS (and streams > 1)
855 * - for fallback rates, to increase chances of getting through
856 */
857 if (offset > 0 ||
858 (mi->sta->smps_mode == IEEE80211_SMPS_DYNAMIC &&
859 group->streams > 1)) {
860 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
861 flags |= IEEE80211_TX_RC_USE_RTS_CTS;
862 }
863
864 ratetbl->rate[offset].idx = idx;
865 ratetbl->rate[offset].flags = flags;
866 }
867
868 static inline int
minstrel_ht_get_prob_ewma(struct minstrel_ht_sta * mi,int rate)869 minstrel_ht_get_prob_ewma(struct minstrel_ht_sta *mi, int rate)
870 {
871 int group = rate / MCS_GROUP_RATES;
872 rate %= MCS_GROUP_RATES;
873 return mi->groups[group].rates[rate].prob_ewma;
874 }
875
876 static int
minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta * mi)877 minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta *mi)
878 {
879 int group = mi->max_prob_rate / MCS_GROUP_RATES;
880 const struct mcs_group *g = &minstrel_mcs_groups[group];
881 int rate = mi->max_prob_rate % MCS_GROUP_RATES;
882
883 /* Disable A-MSDU if max_prob_rate is bad */
884 if (mi->groups[group].rates[rate].prob_ewma < MINSTREL_FRAC(50, 100))
885 return 1;
886
887 /* If the rate is slower than single-stream MCS1, make A-MSDU limit small */
888 if (g->duration[rate] > MCS_DURATION(1, 0, 52))
889 return 500;
890
891 /*
892 * If the rate is slower than single-stream MCS4, limit A-MSDU to usual
893 * data packet size
894 */
895 if (g->duration[rate] > MCS_DURATION(1, 0, 104))
896 return 1600;
897
898 /*
899 * If the rate is slower than single-stream MCS7, or if the max throughput
900 * rate success probability is less than 75%, limit A-MSDU to twice the usual
901 * data packet size
902 */
903 if (g->duration[rate] > MCS_DURATION(1, 0, 260) ||
904 (minstrel_ht_get_prob_ewma(mi, mi->max_tp_rate[0]) <
905 MINSTREL_FRAC(75, 100)))
906 return 3200;
907
908 /*
909 * HT A-MPDU limits maximum MPDU size under BA agreement to 4095 bytes.
910 * Since aggregation sessions are started/stopped without txq flush, use
911 * the limit here to avoid the complexity of having to de-aggregate
912 * packets in the queue.
913 */
914 if (!mi->sta->vht_cap.vht_supported)
915 return IEEE80211_MAX_MPDU_LEN_HT_BA;
916
917 /* unlimited */
918 return 0;
919 }
920
921 static void
minstrel_ht_update_rates(struct minstrel_priv * mp,struct minstrel_ht_sta * mi)922 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
923 {
924 struct ieee80211_sta_rates *rates;
925 int i = 0;
926
927 rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
928 if (!rates)
929 return;
930
931 /* Start with max_tp_rate[0] */
932 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
933
934 if (mp->hw->max_rates >= 3) {
935 /* At least 3 tx rates supported, use max_tp_rate[1] next */
936 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]);
937 }
938
939 if (mp->hw->max_rates >= 2) {
940 /*
941 * At least 2 tx rates supported, use max_prob_rate next */
942 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
943 }
944
945 mi->sta->max_rc_amsdu_len = minstrel_ht_get_max_amsdu_len(mi);
946 rates->rate[i].idx = -1;
947 rate_control_set_rates(mp->hw, mi->sta, rates);
948 }
949
950 static inline int
minstrel_get_duration(int index)951 minstrel_get_duration(int index)
952 {
953 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
954 return group->duration[index % MCS_GROUP_RATES];
955 }
956
957 static int
minstrel_get_sample_rate(struct minstrel_priv * mp,struct minstrel_ht_sta * mi)958 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
959 {
960 struct minstrel_rate_stats *mrs;
961 struct minstrel_mcs_group_data *mg;
962 unsigned int sample_dur, sample_group, cur_max_tp_streams;
963 int tp_rate1, tp_rate2;
964 int sample_idx = 0;
965
966 if (mi->sample_wait > 0) {
967 mi->sample_wait--;
968 return -1;
969 }
970
971 if (!mi->sample_tries)
972 return -1;
973
974 sample_group = mi->sample_group;
975 mg = &mi->groups[sample_group];
976 sample_idx = sample_table[mg->column][mg->index];
977 minstrel_set_next_sample_idx(mi);
978
979 if (!(mi->supported[sample_group] & BIT(sample_idx)))
980 return -1;
981
982 mrs = &mg->rates[sample_idx];
983 sample_idx += sample_group * MCS_GROUP_RATES;
984
985 /* Set tp_rate1, tp_rate2 to the highest / second highest max_tp_rate */
986 if (minstrel_get_duration(mi->max_tp_rate[0]) >
987 minstrel_get_duration(mi->max_tp_rate[1])) {
988 tp_rate1 = mi->max_tp_rate[1];
989 tp_rate2 = mi->max_tp_rate[0];
990 } else {
991 tp_rate1 = mi->max_tp_rate[0];
992 tp_rate2 = mi->max_tp_rate[1];
993 }
994
995 /*
996 * Sampling might add some overhead (RTS, no aggregation)
997 * to the frame. Hence, don't use sampling for the highest currently
998 * used highest throughput or probability rate.
999 */
1000 if (sample_idx == mi->max_tp_rate[0] || sample_idx == mi->max_prob_rate)
1001 return -1;
1002
1003 /*
1004 * Do not sample if the probability is already higher than 95%
1005 * to avoid wasting airtime.
1006 */
1007 if (mrs->prob_ewma > MINSTREL_FRAC(95, 100))
1008 return -1;
1009
1010 /*
1011 * Make sure that lower rates get sampled only occasionally,
1012 * if the link is working perfectly.
1013 */
1014
1015 cur_max_tp_streams = minstrel_mcs_groups[tp_rate1 /
1016 MCS_GROUP_RATES].streams;
1017 sample_dur = minstrel_get_duration(sample_idx);
1018 if (sample_dur >= minstrel_get_duration(tp_rate2) &&
1019 (cur_max_tp_streams - 1 <
1020 minstrel_mcs_groups[sample_group].streams ||
1021 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
1022 if (mrs->sample_skipped < 20)
1023 return -1;
1024
1025 if (mi->sample_slow++ > 2)
1026 return -1;
1027 }
1028 mi->sample_tries--;
1029
1030 return sample_idx;
1031 }
1032
1033 static void
minstrel_ht_get_rate(void * priv,struct ieee80211_sta * sta,void * priv_sta,struct ieee80211_tx_rate_control * txrc)1034 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
1035 struct ieee80211_tx_rate_control *txrc)
1036 {
1037 const struct mcs_group *sample_group;
1038 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
1039 struct ieee80211_tx_rate *rate = &info->status.rates[0];
1040 struct minstrel_ht_sta_priv *msp = priv_sta;
1041 struct minstrel_ht_sta *mi = &msp->ht;
1042 struct minstrel_priv *mp = priv;
1043 int sample_idx;
1044
1045 if (rate_control_send_low(sta, priv_sta, txrc))
1046 return;
1047
1048 if (!msp->is_ht)
1049 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
1050
1051 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
1052 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
1053 minstrel_aggr_check(sta, txrc->skb);
1054
1055 info->flags |= mi->tx_flags;
1056
1057 #ifdef CONFIG_MAC80211_DEBUGFS
1058 if (mp->fixed_rate_idx != -1)
1059 return;
1060 #endif
1061
1062 /* Don't use EAPOL frames for sampling on non-mrr hw */
1063 if (mp->hw->max_rates == 1 &&
1064 (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
1065 sample_idx = -1;
1066 else
1067 sample_idx = minstrel_get_sample_rate(mp, mi);
1068
1069 mi->total_packets++;
1070
1071 /* wraparound */
1072 if (mi->total_packets == ~0) {
1073 mi->total_packets = 0;
1074 mi->sample_packets = 0;
1075 }
1076
1077 if (sample_idx < 0)
1078 return;
1079
1080 sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
1081 sample_idx %= MCS_GROUP_RATES;
1082
1083 if (sample_group == &minstrel_mcs_groups[MINSTREL_CCK_GROUP] &&
1084 (sample_idx >= 4) != txrc->short_preamble)
1085 return;
1086
1087 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
1088 rate->count = 1;
1089
1090 if (sample_group == &minstrel_mcs_groups[MINSTREL_CCK_GROUP]) {
1091 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
1092 rate->idx = mp->cck_rates[idx];
1093 } else if (sample_group->flags & IEEE80211_TX_RC_VHT_MCS) {
1094 ieee80211_rate_set_vht(rate, sample_idx % MCS_GROUP_RATES,
1095 sample_group->streams);
1096 } else {
1097 rate->idx = sample_idx + (sample_group->streams - 1) * 8;
1098 }
1099
1100 rate->flags = sample_group->flags;
1101 }
1102
1103 static void
minstrel_ht_update_cck(struct minstrel_priv * mp,struct minstrel_ht_sta * mi,struct ieee80211_supported_band * sband,struct ieee80211_sta * sta)1104 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1105 struct ieee80211_supported_band *sband,
1106 struct ieee80211_sta *sta)
1107 {
1108 int i;
1109
1110 if (sband->band != NL80211_BAND_2GHZ)
1111 return;
1112
1113 if (!ieee80211_hw_check(mp->hw, SUPPORTS_HT_CCK_RATES))
1114 return;
1115
1116 mi->cck_supported = 0;
1117 mi->cck_supported_short = 0;
1118 for (i = 0; i < 4; i++) {
1119 if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
1120 continue;
1121
1122 mi->cck_supported |= BIT(i);
1123 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
1124 mi->cck_supported_short |= BIT(i);
1125 }
1126
1127 mi->supported[MINSTREL_CCK_GROUP] = mi->cck_supported;
1128 }
1129
1130 static void
minstrel_ht_update_caps(void * priv,struct ieee80211_supported_band * sband,struct cfg80211_chan_def * chandef,struct ieee80211_sta * sta,void * priv_sta)1131 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
1132 struct cfg80211_chan_def *chandef,
1133 struct ieee80211_sta *sta, void *priv_sta)
1134 {
1135 struct minstrel_priv *mp = priv;
1136 struct minstrel_ht_sta_priv *msp = priv_sta;
1137 struct minstrel_ht_sta *mi = &msp->ht;
1138 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
1139 u16 sta_cap = sta->ht_cap.cap;
1140 struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap;
1141 int use_vht;
1142 int n_supported = 0;
1143 int ack_dur;
1144 int stbc;
1145 int i;
1146
1147 /* fall back to the old minstrel for legacy stations */
1148 if (!sta->ht_cap.ht_supported)
1149 goto use_legacy;
1150
1151 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != MINSTREL_GROUPS_NB);
1152
1153 #ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
1154 if (vht_cap->vht_supported)
1155 use_vht = vht_cap->vht_mcs.tx_mcs_map != cpu_to_le16(~0);
1156 else
1157 #endif
1158 use_vht = 0;
1159
1160 msp->is_ht = true;
1161 memset(mi, 0, sizeof(*mi));
1162
1163 mi->sta = sta;
1164 mi->last_stats_update = jiffies;
1165
1166 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
1167 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
1168 mi->overhead += ack_dur;
1169 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
1170
1171 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
1172
1173 /* When using MRR, sample more on the first attempt, without delay */
1174 if (mp->has_mrr) {
1175 mi->sample_count = 16;
1176 mi->sample_wait = 0;
1177 } else {
1178 mi->sample_count = 8;
1179 mi->sample_wait = 8;
1180 }
1181 mi->sample_tries = 4;
1182
1183 /* TODO tx_flags for vht - ATM the RC API is not fine-grained enough */
1184 if (!use_vht) {
1185 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
1186 IEEE80211_HT_CAP_RX_STBC_SHIFT;
1187 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
1188
1189 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
1190 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
1191 }
1192
1193 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
1194 u32 gflags = minstrel_mcs_groups[i].flags;
1195 int bw, nss;
1196
1197 mi->supported[i] = 0;
1198 if (i == MINSTREL_CCK_GROUP) {
1199 minstrel_ht_update_cck(mp, mi, sband, sta);
1200 continue;
1201 }
1202
1203 if (gflags & IEEE80211_TX_RC_SHORT_GI) {
1204 if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
1205 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
1206 continue;
1207 } else {
1208 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
1209 continue;
1210 }
1211 }
1212
1213 if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
1214 sta->bandwidth < IEEE80211_STA_RX_BW_40)
1215 continue;
1216
1217 nss = minstrel_mcs_groups[i].streams;
1218
1219 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
1220 if (sta->smps_mode == IEEE80211_SMPS_STATIC && nss > 1)
1221 continue;
1222
1223 /* HT rate */
1224 if (gflags & IEEE80211_TX_RC_MCS) {
1225 #ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
1226 if (use_vht && minstrel_vht_only)
1227 continue;
1228 #endif
1229 mi->supported[i] = mcs->rx_mask[nss - 1];
1230 if (mi->supported[i])
1231 n_supported++;
1232 continue;
1233 }
1234
1235 /* VHT rate */
1236 if (!vht_cap->vht_supported ||
1237 WARN_ON(!(gflags & IEEE80211_TX_RC_VHT_MCS)) ||
1238 WARN_ON(gflags & IEEE80211_TX_RC_160_MHZ_WIDTH))
1239 continue;
1240
1241 if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH) {
1242 if (sta->bandwidth < IEEE80211_STA_RX_BW_80 ||
1243 ((gflags & IEEE80211_TX_RC_SHORT_GI) &&
1244 !(vht_cap->cap & IEEE80211_VHT_CAP_SHORT_GI_80))) {
1245 continue;
1246 }
1247 }
1248
1249 if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH)
1250 bw = BW_40;
1251 else if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH)
1252 bw = BW_80;
1253 else
1254 bw = BW_20;
1255
1256 mi->supported[i] = minstrel_get_valid_vht_rates(bw, nss,
1257 vht_cap->vht_mcs.tx_mcs_map);
1258
1259 if (mi->supported[i])
1260 n_supported++;
1261 }
1262
1263 if (!n_supported)
1264 goto use_legacy;
1265
1266 mi->supported[MINSTREL_CCK_GROUP] |= mi->cck_supported_short << 4;
1267
1268 /* create an initial rate table with the lowest supported rates */
1269 minstrel_ht_update_stats(mp, mi);
1270 minstrel_ht_update_rates(mp, mi);
1271
1272 return;
1273
1274 use_legacy:
1275 msp->is_ht = false;
1276 memset(&msp->legacy, 0, sizeof(msp->legacy));
1277 msp->legacy.r = msp->ratelist;
1278 msp->legacy.sample_table = msp->sample_table;
1279 return mac80211_minstrel.rate_init(priv, sband, chandef, sta,
1280 &msp->legacy);
1281 }
1282
1283 static void
minstrel_ht_rate_init(void * priv,struct ieee80211_supported_band * sband,struct cfg80211_chan_def * chandef,struct ieee80211_sta * sta,void * priv_sta)1284 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
1285 struct cfg80211_chan_def *chandef,
1286 struct ieee80211_sta *sta, void *priv_sta)
1287 {
1288 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1289 }
1290
1291 static void
minstrel_ht_rate_update(void * priv,struct ieee80211_supported_band * sband,struct cfg80211_chan_def * chandef,struct ieee80211_sta * sta,void * priv_sta,u32 changed)1292 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
1293 struct cfg80211_chan_def *chandef,
1294 struct ieee80211_sta *sta, void *priv_sta,
1295 u32 changed)
1296 {
1297 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1298 }
1299
1300 static void *
minstrel_ht_alloc_sta(void * priv,struct ieee80211_sta * sta,gfp_t gfp)1301 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
1302 {
1303 struct ieee80211_supported_band *sband;
1304 struct minstrel_ht_sta_priv *msp;
1305 struct minstrel_priv *mp = priv;
1306 struct ieee80211_hw *hw = mp->hw;
1307 int max_rates = 0;
1308 int i;
1309
1310 for (i = 0; i < NUM_NL80211_BANDS; i++) {
1311 sband = hw->wiphy->bands[i];
1312 if (sband && sband->n_bitrates > max_rates)
1313 max_rates = sband->n_bitrates;
1314 }
1315
1316 msp = kzalloc(sizeof(*msp), gfp);
1317 if (!msp)
1318 return NULL;
1319
1320 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
1321 if (!msp->ratelist)
1322 goto error;
1323
1324 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
1325 if (!msp->sample_table)
1326 goto error1;
1327
1328 return msp;
1329
1330 error1:
1331 kfree(msp->ratelist);
1332 error:
1333 kfree(msp);
1334 return NULL;
1335 }
1336
1337 static void
minstrel_ht_free_sta(void * priv,struct ieee80211_sta * sta,void * priv_sta)1338 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1339 {
1340 struct minstrel_ht_sta_priv *msp = priv_sta;
1341
1342 kfree(msp->sample_table);
1343 kfree(msp->ratelist);
1344 kfree(msp);
1345 }
1346
1347 static void *
minstrel_ht_alloc(struct ieee80211_hw * hw,struct dentry * debugfsdir)1348 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
1349 {
1350 return mac80211_minstrel.alloc(hw, debugfsdir);
1351 }
1352
1353 static void
minstrel_ht_free(void * priv)1354 minstrel_ht_free(void *priv)
1355 {
1356 mac80211_minstrel.free(priv);
1357 }
1358
minstrel_ht_get_expected_throughput(void * priv_sta)1359 static u32 minstrel_ht_get_expected_throughput(void *priv_sta)
1360 {
1361 struct minstrel_ht_sta_priv *msp = priv_sta;
1362 struct minstrel_ht_sta *mi = &msp->ht;
1363 int i, j, prob, tp_avg;
1364
1365 if (!msp->is_ht)
1366 return mac80211_minstrel.get_expected_throughput(priv_sta);
1367
1368 i = mi->max_tp_rate[0] / MCS_GROUP_RATES;
1369 j = mi->max_tp_rate[0] % MCS_GROUP_RATES;
1370 prob = mi->groups[i].rates[j].prob_ewma;
1371
1372 /* convert tp_avg from pkt per second in kbps */
1373 tp_avg = minstrel_ht_get_tp_avg(mi, i, j, prob) * 10;
1374 tp_avg = tp_avg * AVG_PKT_SIZE * 8 / 1024;
1375
1376 return tp_avg;
1377 }
1378
1379 static const struct rate_control_ops mac80211_minstrel_ht = {
1380 .name = "minstrel_ht",
1381 .tx_status_ext = minstrel_ht_tx_status,
1382 .get_rate = minstrel_ht_get_rate,
1383 .rate_init = minstrel_ht_rate_init,
1384 .rate_update = minstrel_ht_rate_update,
1385 .alloc_sta = minstrel_ht_alloc_sta,
1386 .free_sta = minstrel_ht_free_sta,
1387 .alloc = minstrel_ht_alloc,
1388 .free = minstrel_ht_free,
1389 #ifdef CONFIG_MAC80211_DEBUGFS
1390 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
1391 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
1392 #endif
1393 .get_expected_throughput = minstrel_ht_get_expected_throughput,
1394 };
1395
1396
init_sample_table(void)1397 static void __init init_sample_table(void)
1398 {
1399 int col, i, new_idx;
1400 u8 rnd[MCS_GROUP_RATES];
1401
1402 memset(sample_table, 0xff, sizeof(sample_table));
1403 for (col = 0; col < SAMPLE_COLUMNS; col++) {
1404 prandom_bytes(rnd, sizeof(rnd));
1405 for (i = 0; i < MCS_GROUP_RATES; i++) {
1406 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1407 while (sample_table[col][new_idx] != 0xff)
1408 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1409
1410 sample_table[col][new_idx] = i;
1411 }
1412 }
1413 }
1414
1415 int __init
rc80211_minstrel_ht_init(void)1416 rc80211_minstrel_ht_init(void)
1417 {
1418 init_sample_table();
1419 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1420 }
1421
1422 void
rc80211_minstrel_ht_exit(void)1423 rc80211_minstrel_ht_exit(void)
1424 {
1425 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
1426 }
1427