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mac80211: minstrel_ht: replace some occurences of MCS_GROUP_RATES
[deliverable/linux.git] / net / mac80211 / rc80211_minstrel_ht.c
CommitLineData
ec8aa669 1/*
a0497f9f 2 * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>
ec8aa669
FF		 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/ieee80211.h>
14#include <net/mac80211.h>
15#include "rate.h"
16#include "rc80211_minstrel.h"
17#include "rc80211_minstrel_ht.h"
18
19#define AVG_PKT_SIZE 1200
ec8aa669
FF		 20
21/* Number of bits for an average sized packet */
22#define MCS_NBITS (AVG_PKT_SIZE << 3)
23
24/* Number of symbols for a packet with (bps) bits per symbol */
25#define MCS_NSYMS(bps) ((MCS_NBITS + (bps) - 1) / (bps))
26
ed97a13c 27/* Transmission time (nanoseconds) for a packet containing (syms) symbols */
ec8aa669
FF		 28#define MCS_SYMBOL_TIME(sgi, syms) \
29 (sgi ? \
ed97a13c
FF		 30 ((syms) * 18000 + 4000) / 5 : /* syms * 3.6 us */ \
31 ((syms) * 1000) << 2 /* syms * 4 us */ \
ec8aa669
FF		 32 )
33
34/* Transmit duration for the raw data part of an average sized packet */
35#define MCS_DURATION(streams, sgi, bps) MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps)))
36
a5f69d94
HS		 37/*
38 * Define group sort order: HT40 -> SGI -> #streams
39 */
40#define GROUP_IDX(_streams, _sgi, _ht40) \
41 MINSTREL_MAX_STREAMS * 2 * _ht40 + \
42 MINSTREL_MAX_STREAMS * _sgi + \
43 _streams - 1
44
ec8aa669 45/* MCS rate information for an MCS group */
a5f69d94
HS		 46#define MCS_GROUP(_streams, _sgi, _ht40) \
47 [GROUP_IDX(_streams, _sgi, _ht40)] = { \
ec8aa669
FF		 48 .streams = _streams, \
49 .flags = \
50 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
51 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
52 .duration = { \
53 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \
54 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \
55 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \
56 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \
57 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \
58 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \
59 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \
60 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \
61 } \
62}
63
a0497f9f 64#define CCK_DURATION(_bitrate, _short, _len) \
ed97a13c 65 (1000 * (10 /* SIFS */ + \
a0497f9f 66 (_short ? 72 + 24 : 144 + 48 ) + \
ed97a13c 67 (8 * (_len + 4) * 10) / (_bitrate)))
a0497f9f
FF		 68
69#define CCK_ACK_DURATION(_bitrate, _short) \
70 (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) + \
71 CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))
72
73#define CCK_DURATION_LIST(_short) \
74 CCK_ACK_DURATION(10, _short), \
75 CCK_ACK_DURATION(20, _short), \
76 CCK_ACK_DURATION(55, _short), \
77 CCK_ACK_DURATION(110, _short)
78
79#define CCK_GROUP \
80 [MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS] = { \
81 .streams = 0, \
82 .duration = { \
83 CCK_DURATION_LIST(false), \
84 CCK_DURATION_LIST(true) \
85 } \
86 }
87
ec8aa669
FF		 88/*
89 * To enable sufficiently targeted rate sampling, MCS rates are divided into
90 * groups, based on the number of streams and flags (HT40, SGI) that they
91 * use.
a5f69d94
HS		 92 *
93 * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
94 * HT40 -> SGI -> #streams
ec8aa669
FF		 95 */
96const struct mcs_group minstrel_mcs_groups[] = {
97 MCS_GROUP(1, 0, 0),
98 MCS_GROUP(2, 0, 0),
99#if MINSTREL_MAX_STREAMS >= 3
100 MCS_GROUP(3, 0, 0),
101#endif
102
103 MCS_GROUP(1, 1, 0),
104 MCS_GROUP(2, 1, 0),
105#if MINSTREL_MAX_STREAMS >= 3
106 MCS_GROUP(3, 1, 0),
107#endif
108
109 MCS_GROUP(1, 0, 1),
110 MCS_GROUP(2, 0, 1),
111#if MINSTREL_MAX_STREAMS >= 3
112 MCS_GROUP(3, 0, 1),
113#endif
114
115 MCS_GROUP(1, 1, 1),
116 MCS_GROUP(2, 1, 1),
117#if MINSTREL_MAX_STREAMS >= 3
118 MCS_GROUP(3, 1, 1),
119#endif
a0497f9f
FF		 120
121 /* must be last */
122 CCK_GROUP
ec8aa669
FF		 123};
124
a0497f9f
FF		 125#define MINSTREL_CCK_GROUP (ARRAY_SIZE(minstrel_mcs_groups) - 1)
126
ec8aa669
FF		 127static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES];
128
a8566662
FF		 129static void
130minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
131
ec8aa669
FF		 132/*
133 * Look up an MCS group index based on mac80211 rate information
134 */
135static int
136minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
137{
7a5e3fa2 138 return GROUP_IDX((rate->idx / 8) + 1,
a5f69d94
HS		 139 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
140 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
ec8aa669
FF		 141}
142
a0497f9f
FF		 143static struct minstrel_rate_stats *
144minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
145 struct ieee80211_tx_rate *rate)
146{
147 int group, idx;
148
149 if (rate->flags & IEEE80211_TX_RC_MCS) {
150 group = minstrel_ht_get_group_idx(rate);
7a5e3fa2 151 idx = rate->idx % 8;
a0497f9f
FF		 152 } else {
153 group = MINSTREL_CCK_GROUP;
154
155 for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++)
156 if (rate->idx == mp->cck_rates[idx])
157 break;
158
159 /* short preamble */
160 if (!(mi->groups[group].supported & BIT(idx)))
161 idx += 4;
162 }
163 return &mi->groups[group].rates[idx];
164}
165
ec8aa669
FF		 166static inline struct minstrel_rate_stats *
167minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
168{
169 return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
170}
171
172
173/*
174 * Recalculate success probabilities and counters for a rate using EWMA
175 */
176static void
6048d763 177minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr)
ec8aa669
FF		 178{
179 if (unlikely(mr->attempts > 0)) {
180 mr->sample_skipped = 0;
181 mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
182 if (!mr->att_hist)
183 mr->probability = mr->cur_prob;
184 else
185 mr->probability = minstrel_ewma(mr->probability,
186 mr->cur_prob, EWMA_LEVEL);
187 mr->att_hist += mr->attempts;
188 mr->succ_hist += mr->success;
189 } else {
190 mr->sample_skipped++;
191 }
192 mr->last_success = mr->success;
193 mr->last_attempts = mr->attempts;
194 mr->success = 0;
195 mr->attempts = 0;
196}
197
198/*
199 * Calculate throughput based on the average A-MPDU length, taking into account
200 * the expected number of retransmissions and their expected length
201 */
202static void
6048d763 203minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
ec8aa669
FF		 204{
205 struct minstrel_rate_stats *mr;
ed97a13c
FF		 206 unsigned int nsecs = 0;
207 unsigned int tp;
3e8b1eb2 208 unsigned int prob;
ec8aa669
FF		 209
210 mr = &mi->groups[group].rates[rate];
3e8b1eb2 211 prob = mr->probability;
ec8aa669 212
3e8b1eb2 213 if (prob < MINSTREL_FRAC(1, 10)) {
ec8aa669
FF		 214 mr->cur_tp = 0;
215 return;
216 }
217
3e8b1eb2
FF		 218 /*
219 * For the throughput calculation, limit the probability value to 90% to
220 * account for collision related packet error rate fluctuation
221 */
222 if (prob > MINSTREL_FRAC(9, 10))
223 prob = MINSTREL_FRAC(9, 10);
224
a0497f9f 225 if (group != MINSTREL_CCK_GROUP)
ed97a13c 226 nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
a0497f9f 227
ed97a13c
FF		 228 nsecs += minstrel_mcs_groups[group].duration[rate];
229 tp = 1000000 * ((mr->probability * 1000) / nsecs);
230
231 mr->cur_tp = MINSTREL_TRUNC(tp);
ec8aa669
FF		 232}
233
234/*
235 * Update rate statistics and select new primary rates
236 *
237 * Rules for rate selection:
238 * - max_prob_rate must use only one stream, as a tradeoff between delivery
239 * probability and throughput during strong fluctuations
240 * - as long as the max prob rate has a probability of more than 3/4, pick
241 * higher throughput rates, even if the probablity is a bit lower
242 */
243static void
244minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
245{
246 struct minstrel_mcs_group_data *mg;
247 struct minstrel_rate_stats *mr;
248 int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
249 int group, i, index;
c2eb5b0f 250 bool mi_rates_valid = false;
ec8aa669
FF		 251
252 if (mi->ampdu_packets > 0) {
253 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
254 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
255 mi->ampdu_len = 0;
256 mi->ampdu_packets = 0;
257 }
258
259 mi->sample_slow = 0;
260 mi->sample_count = 0;
ec8aa669
FF		 261
262 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
c2eb5b0f
KB		 263 bool mg_rates_valid = false;
264
ec8aa669
FF		 265 cur_prob = 0;
266 cur_prob_tp = 0;
267 cur_tp = 0;
268 cur_tp2 = 0;
269
270 mg = &mi->groups[group];
271 if (!mg->supported)
272 continue;
273
ec8aa669
FF		 274 mi->sample_count++;
275
276 for (i = 0; i < MCS_GROUP_RATES; i++) {
277 if (!(mg->supported & BIT(i)))
278 continue;
279
c2eb5b0f
KB		 280 /* initialize rates selections starting indexes */
281 if (!mg_rates_valid) {
282 mg->max_tp_rate = mg->max_tp_rate2 =
283 mg->max_prob_rate = i;
284 if (!mi_rates_valid) {
285 mi->max_tp_rate = mi->max_tp_rate2 =
286 mi->max_prob_rate = i;
287 mi_rates_valid = true;
288 }
289 mg_rates_valid = true;
290 }
291
ec8aa669
FF		 292 mr = &mg->rates[i];
293 mr->retry_updated = false;
294 index = MCS_GROUP_RATES * group + i;
6048d763
PK		 295 minstrel_calc_rate_ewma(mr);
296 minstrel_ht_calc_tp(mi, group, i);
ec8aa669
FF		 297
298 if (!mr->cur_tp)
299 continue;
300
ec8aa669
FF		 301 if ((mr->cur_tp > cur_prob_tp && mr->probability >
302 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
303 mg->max_prob_rate = index;
304 cur_prob = mr->probability;
009271f9 305 cur_prob_tp = mr->cur_tp;
ec8aa669
FF		 306 }
307
308 if (mr->cur_tp > cur_tp) {
309 swap(index, mg->max_tp_rate);
310 cur_tp = mr->cur_tp;
311 mr = minstrel_get_ratestats(mi, index);
312 }
313
314 if (index >= mg->max_tp_rate)
315 continue;
316
317 if (mr->cur_tp > cur_tp2) {
318 mg->max_tp_rate2 = index;
319 cur_tp2 = mr->cur_tp;
320 }
321 }
322 }
323
96d4ac3f
FF		 324 /* try to sample all available rates during each interval */
325 mi->sample_count *= 8;
ec8aa669
FF		 326
327 cur_prob = 0;
328 cur_prob_tp = 0;
329 cur_tp = 0;
330 cur_tp2 = 0;
331 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
332 mg = &mi->groups[group];
333 if (!mg->supported)
334 continue;
335
ec8aa669
FF		 336 mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
337 if (cur_tp < mr->cur_tp) {
89888e36
LB		 338 mi->max_tp_rate2 = mi->max_tp_rate;
339 cur_tp2 = cur_tp;
ec8aa669
FF		 340 mi->max_tp_rate = mg->max_tp_rate;
341 cur_tp = mr->cur_tp;
965237ab 342 mi->max_prob_streams = minstrel_mcs_groups[group].streams - 1;
ec8aa669
FF		 343 }
344
345 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
346 if (cur_tp2 < mr->cur_tp) {
347 mi->max_tp_rate2 = mg->max_tp_rate2;
348 cur_tp2 = mr->cur_tp;
349 }
350 }
351
965237ab
FF		 352 if (mi->max_prob_streams < 1)
353 mi->max_prob_streams = 1;
a299c6d5
FF		 354
355 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
356 mg = &mi->groups[group];
357 if (!mg->supported)
358 continue;
359 mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
360 if (cur_prob_tp < mr->cur_tp &&
965237ab 361 minstrel_mcs_groups[group].streams <= mi->max_prob_streams) {
a299c6d5
FF		 362 mi->max_prob_rate = mg->max_prob_rate;
363 cur_prob = mr->cur_prob;
364 cur_prob_tp = mr->cur_tp;
365 }
366 }
367
37feb7e2
LB		 368#ifdef CONFIG_MAC80211_DEBUGFS
369 /* use fixed index if set */
370 if (mp->fixed_rate_idx != -1) {
371 mi->max_tp_rate = mp->fixed_rate_idx;
372 mi->max_tp_rate2 = mp->fixed_rate_idx;
373 mi->max_prob_rate = mp->fixed_rate_idx;
374 }
375#endif
a299c6d5 376
ec8aa669
FF		 377 mi->stats_update = jiffies;
378}
379
380static bool
a0497f9f 381minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
ec8aa669 382{
b79296be 383 if (rate->idx < 0)
ec8aa669
FF		 384 return false;
385
b79296be 386 if (!rate->count)
ec8aa669
FF		 387 return false;
388
a0497f9f
FF		 389 if (rate->flags & IEEE80211_TX_RC_MCS)
390 return true;
391
392 return rate->idx == mp->cck_rates[0] ||
393 rate->idx == mp->cck_rates[1] ||
394 rate->idx == mp->cck_rates[2] ||
395 rate->idx == mp->cck_rates[3];
ec8aa669
FF		 396}
397
398static void
399minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
400{
401 struct minstrel_mcs_group_data *mg;
402
403 for (;;) {
404 mi->sample_group++;
405 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
406 mg = &mi->groups[mi->sample_group];
407
408 if (!mg->supported)
409 continue;
410
411 if (++mg->index >= MCS_GROUP_RATES) {
412 mg->index = 0;
413 if (++mg->column >= ARRAY_SIZE(sample_table))
414 mg->column = 0;
415 }
416 break;
417 }
418}
419
420static void
d5ece215
JL		 421minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx,
422 bool primary)
ec8aa669
FF		 423{
424 int group, orig_group;
425
426 orig_group = group = *idx / MCS_GROUP_RATES;
427 while (group > 0) {
428 group--;
429
430 if (!mi->groups[group].supported)
431 continue;
432
433 if (minstrel_mcs_groups[group].streams >
434 minstrel_mcs_groups[orig_group].streams)
435 continue;
436
437 if (primary)
438 *idx = mi->groups[group].max_tp_rate;
439 else
440 *idx = mi->groups[group].max_tp_rate2;
441 break;
442 }
443}
444
445static void
6048d763 446minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
ec8aa669
FF		 447{
448 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
449 struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
450 u16 tid;
451
452 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
453 return;
454
e133fae2 455 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
ec8aa669
FF		 456 return;
457
458 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
a622ab72 459 if (likely(sta->ampdu_mlme.tid_tx[tid]))
ec8aa669
FF		 460 return;
461
48124d1a
LR		 462 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
463 return;
464
bd2ce6e4 465 ieee80211_start_tx_ba_session(pubsta, tid, 5000);
ec8aa669
FF		 466}
467
468static void
469minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
470 struct ieee80211_sta *sta, void *priv_sta,
471 struct sk_buff *skb)
472{
473 struct minstrel_ht_sta_priv *msp = priv_sta;
474 struct minstrel_ht_sta *mi = &msp->ht;
475 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
476 struct ieee80211_tx_rate *ar = info->status.rates;
477 struct minstrel_rate_stats *rate, *rate2;
478 struct minstrel_priv *mp = priv;
a8566662 479 bool last, update = false;
a544ab7f 480 int i;
ec8aa669
FF		 481
482 if (!msp->is_ht)
483 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
484
485 /* This packet was aggregated but doesn't carry status info */
486 if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
487 !(info->flags & IEEE80211_TX_STAT_AMPDU))
488 return;
489
15d46f38
BS		 490 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
491 info->status.ampdu_ack_len =
492 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
ec8aa669
FF		 493 info->status.ampdu_len = 1;
494 }
495
496 mi->ampdu_packets++;
497 mi->ampdu_len += info->status.ampdu_len;
498
499 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
c7317e41 500 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
52c00a37 501 mi->sample_tries = 1;
ec8aa669
FF		 502 mi->sample_count--;
503 }
504
8d5eab5a 505 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
ec8aa669 506 mi->sample_packets += info->status.ampdu_len;
ec8aa669 507
a0497f9f 508 last = !minstrel_ht_txstat_valid(mp, &ar[0]);
ec8aa669
FF		 509 for (i = 0; !last; i++) {
510 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
a0497f9f 511 !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
ec8aa669 512
a0497f9f 513 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
ec8aa669 514
15d46f38 515 if (last)
ec8aa669
FF		 516 rate->success += info->status.ampdu_ack_len;
517
518 rate->attempts += ar[i].count * info->status.ampdu_len;
519 }
520
521 /*
522 * check for sudden death of spatial multiplexing,
523 * downgrade to a lower number of streams if necessary.
524 */
525 rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
526 if (rate->attempts > 30 &&
527 MINSTREL_FRAC(rate->success, rate->attempts) <
a8566662 528 MINSTREL_FRAC(20, 100)) {
ec8aa669 529 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
a8566662
FF		 530 update = true;
531 }
ec8aa669
FF		 532
533 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
ecc3d5ae
ML		 534 if (rate2->attempts > 30 &&
535 MINSTREL_FRAC(rate2->success, rate2->attempts) <
a8566662 536 MINSTREL_FRAC(20, 100)) {
ec8aa669 537 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
a8566662
FF		 538 update = true;
539 }
ec8aa669
FF		 540
541 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
a8566662 542 update = true;
ec8aa669 543 minstrel_ht_update_stats(mp, mi);
a0497f9f
FF		 544 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
545 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
6048d763 546 minstrel_aggr_check(sta, skb);
ec8aa669 547 }
a8566662
FF		 548
549 if (update)
550 minstrel_ht_update_rates(mp, mi);
ec8aa669
FF		 551}
552
553static void
554minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
555 int index)
556{
557 struct minstrel_rate_stats *mr;
558 const struct mcs_group *group;
559 unsigned int tx_time, tx_time_rtscts, tx_time_data;
560 unsigned int cw = mp->cw_min;
8fddddff 561 unsigned int ctime = 0;
ec8aa669
FF		 562 unsigned int t_slot = 9; /* FIXME */
563 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
a0497f9f 564 unsigned int overhead = 0, overhead_rtscts = 0;
ec8aa669
FF		 565
566 mr = minstrel_get_ratestats(mi, index);
567 if (mr->probability < MINSTREL_FRAC(1, 10)) {
568 mr->retry_count = 1;
569 mr->retry_count_rtscts = 1;
570 return;
571 }
572
573 mr->retry_count = 2;
574 mr->retry_count_rtscts = 2;
575 mr->retry_updated = true;
576
577 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
ed97a13c 578 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
8fddddff
DH		 579
580 /* Contention time for first 2 tries */
581 ctime = (t_slot * cw) >> 1;
582 cw = min((cw << 1) | 1, mp->cw_max);
583 ctime += (t_slot * cw) >> 1;
584 cw = min((cw << 1) | 1, mp->cw_max);
585
a0497f9f
FF		 586 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
587 overhead = mi->overhead;
588 overhead_rtscts = mi->overhead_rtscts;
589 }
590
8fddddff 591 /* Total TX time for data and Contention after first 2 tries */
a0497f9f
FF		 592 tx_time = ctime + 2 * (overhead + tx_time_data);
593 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
8fddddff
DH		 594
595 /* See how many more tries we can fit inside segment size */
ec8aa669 596 do {
8fddddff
DH		 597 /* Contention time for this try */
598 ctime = (t_slot * cw) >> 1;
599 cw = min((cw << 1) | 1, mp->cw_max);
600
601 /* Total TX time after this try */
a0497f9f
FF		 602 tx_time += ctime + overhead + tx_time_data;
603 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
8fddddff 604
ec8aa669
FF		 605 if (tx_time_rtscts < mp->segment_size)
606 mr->retry_count_rtscts++;
607 } while ((tx_time < mp->segment_size) &&
608 (++mr->retry_count < mp->max_retry));
609}
610
611
612static void
613minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
a8566662 614 struct ieee80211_sta_rates *ratetbl, int offset, int index)
ec8aa669
FF		 615{
616 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
617 struct minstrel_rate_stats *mr;
a8566662
FF		 618 u8 idx;
619 u16 flags;
ec8aa669
FF		 620
621 mr = minstrel_get_ratestats(mi, index);
622 if (!mr->retry_updated)
623 minstrel_calc_retransmit(mp, mi, index);
624
a8566662
FF		 625 if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) {
626 ratetbl->rate[offset].count = 2;
627 ratetbl->rate[offset].count_rts = 2;
628 ratetbl->rate[offset].count_cts = 2;
629 } else {
630 ratetbl->rate[offset].count = mr->retry_count;
631 ratetbl->rate[offset].count_cts = mr->retry_count;
632 ratetbl->rate[offset].count_rts = mr->retry_count_rtscts;
633 }
a0497f9f
FF		 634
635 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
a8566662
FF		 636 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
637 flags = 0;
638 } else {
7a5e3fa2 639 idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;
a8566662
FF		 640 flags = IEEE80211_TX_RC_MCS | group->flags;
641 }
642
643 if (offset > 0) {
644 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
645 flags |= IEEE80211_TX_RC_USE_RTS_CTS;
646 }
647
648 ratetbl->rate[offset].idx = idx;
649 ratetbl->rate[offset].flags = flags;
650}
651
652static void
653minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
654{
655 struct ieee80211_sta_rates *rates;
656 int i = 0;
657
658 rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
659 if (!rates)
a0497f9f 660 return;
a8566662
FF		 661
662 /* Start with max_tp_rate */
663 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate);
664
665 if (mp->hw->max_rates >= 3) {
666 /* At least 3 tx rates supported, use max_tp_rate2 next */
667 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate2);
668 }
669
670 if (mp->hw->max_rates >= 2) {
671 /*
672 * At least 2 tx rates supported, use max_prob_rate next */
673 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
a0497f9f
FF		 674 }
675
a8566662
FF		 676 rates->rate[i].idx = -1;
677 rate_control_set_rates(mp->hw, mi->sta, rates);
ec8aa669
FF		 678}
679
680static inline int
681minstrel_get_duration(int index)
682{
683 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
684 return group->duration[index % MCS_GROUP_RATES];
685}
686
687static int
688minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
689{
690 struct minstrel_rate_stats *mr;
691 struct minstrel_mcs_group_data *mg;
965237ab 692 unsigned int sample_dur, sample_group;
ec8aa669
FF		 693 int sample_idx = 0;
694
695 if (mi->sample_wait > 0) {
696 mi->sample_wait--;
697 return -1;
698 }
699
700 if (!mi->sample_tries)
701 return -1;
702
ec8aa669
FF		 703 mg = &mi->groups[mi->sample_group];
704 sample_idx = sample_table[mg->column][mg->index];
705 mr = &mg->rates[sample_idx];
965237ab
FF		 706 sample_group = mi->sample_group;
707 sample_idx += sample_group * MCS_GROUP_RATES;
8d5eab5a 708 minstrel_next_sample_idx(mi);
ec8aa669 709
ba6fa29c
HS		 710 /*
711 * Sampling might add some overhead (RTS, no aggregation)
712 * to the frame. Hence, don't use sampling for the currently
a0ca796c 713 * used rates.
ba6fa29c 714 */
a0ca796c
FF		 715 if (sample_idx == mi->max_tp_rate ||
716 sample_idx == mi->max_tp_rate2 ||
717 sample_idx == mi->max_prob_rate)
ba6fa29c 718 return -1;
a0ca796c 719
ec8aa669 720 /*
bc96f242
FF		 721 * Do not sample if the probability is already higher than 95%
722 * to avoid wasting airtime.
ec8aa669 723 */
bc96f242 724 if (mr->probability > MINSTREL_FRAC(95, 100))
8d5eab5a 725 return -1;
ec8aa669
FF		 726
727 /*
728 * Make sure that lower rates get sampled only occasionally,
729 * if the link is working perfectly.
730 */
965237ab
FF		 731 sample_dur = minstrel_get_duration(sample_idx);
732 if (sample_dur >= minstrel_get_duration(mi->max_tp_rate2) &&
733 (mi->max_prob_streams <
734 minstrel_mcs_groups[sample_group].streams ||
735 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
c7317e41 736 if (mr->sample_skipped < 20)
8d5eab5a 737 return -1;
ec8aa669
FF		 738
739 if (mi->sample_slow++ > 2)
8d5eab5a 740 return -1;
ec8aa669 741 }
098b8afb 742 mi->sample_tries--;
ec8aa669
FF		 743
744 return sample_idx;
ec8aa669
FF		 745}
746
a0497f9f
FF		 747static void
748minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp,
749 struct minstrel_ht_sta *mi, bool val)
750{
751 u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported;
752
753 if (!supported || !mi->cck_supported_short)
754 return;
755
756 if (supported & (mi->cck_supported_short << (val * 4)))
757 return;
758
759 supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4);
760 mi->groups[MINSTREL_CCK_GROUP].supported = supported;
761}
762
ec8aa669
FF		 763static void
764minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
765 struct ieee80211_tx_rate_control *txrc)
766{
a8566662 767 const struct mcs_group *sample_group;
ec8aa669 768 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
a8566662 769 struct ieee80211_tx_rate *rate = &info->status.rates[0];
ec8aa669
FF		 770 struct minstrel_ht_sta_priv *msp = priv_sta;
771 struct minstrel_ht_sta *mi = &msp->ht;
772 struct minstrel_priv *mp = priv;
773 int sample_idx;
774
775 if (rate_control_send_low(sta, priv_sta, txrc))
776 return;
777
778 if (!msp->is_ht)
779 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
780
781 info->flags |= mi->tx_flags;
a0497f9f 782 minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble);
6de062ce 783
37feb7e2
LB		 784#ifdef CONFIG_MAC80211_DEBUGFS
785 if (mp->fixed_rate_idx != -1)
786 return;
787#endif
788
6de062ce
HS		 789 /* Don't use EAPOL frames for sampling on non-mrr hw */
790 if (mp->hw->max_rates == 1 &&
af61a165 791 (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
6de062ce
HS		 792 sample_idx = -1;
793 else
794 sample_idx = minstrel_get_sample_rate(mp, mi);
24f7580e 795
ec8aa669
FF		 796 mi->total_packets++;
797
798 /* wraparound */
799 if (mi->total_packets == ~0) {
800 mi->total_packets = 0;
801 mi->sample_packets = 0;
802 }
a8566662
FF		 803
804 if (sample_idx < 0)
805 return;
806
807 sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
808 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
1cd15857
FF		 809 rate->count = 1;
810
811 if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
812 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
813 rate->idx = mp->cck_rates[idx];
814 rate->flags = 0;
815 return;
816 }
817
a8566662 818 rate->idx = sample_idx % MCS_GROUP_RATES +
7a5e3fa2 819 (sample_group->streams - 1) * 8;
a8566662 820 rate->flags = IEEE80211_TX_RC_MCS | sample_group->flags;
ec8aa669
FF		 821}
822
a0497f9f
FF		 823static void
824minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
825 struct ieee80211_supported_band *sband,
826 struct ieee80211_sta *sta)
827{
828 int i;
829
830 if (sband->band != IEEE80211_BAND_2GHZ)
831 return;
832
2dfca312
FF		 833 if (!(mp->hw->flags & IEEE80211_HW_SUPPORTS_HT_CCK_RATES))
834 return;
835
a0497f9f
FF		 836 mi->cck_supported = 0;
837 mi->cck_supported_short = 0;
838 for (i = 0; i < 4; i++) {
839 if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
840 continue;
841
842 mi->cck_supported |= BIT(i);
843 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
844 mi->cck_supported_short |= BIT(i);
845 }
846
847 mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported;
848}
849
ec8aa669
FF		 850static void
851minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
3de805cf 852 struct cfg80211_chan_def *chandef,
64f68e5d 853 struct ieee80211_sta *sta, void *priv_sta)
ec8aa669
FF		 854{
855 struct minstrel_priv *mp = priv;
856 struct minstrel_ht_sta_priv *msp = priv_sta;
857 struct minstrel_ht_sta *mi = &msp->ht;
858 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
ec8aa669 859 u16 sta_cap = sta->ht_cap.cap;
4dc217df 860 int n_supported = 0;
ec8aa669
FF		 861 int ack_dur;
862 int stbc;
863 int i;
864
865 /* fall back to the old minstrel for legacy stations */
4dc217df
FF		 866 if (!sta->ht_cap.ht_supported)
867 goto use_legacy;
ec8aa669
FF		 868
869 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
a0497f9f 870 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1);
ec8aa669
FF		 871
872 msp->is_ht = true;
873 memset(mi, 0, sizeof(*mi));
a8566662
FF		 874
875 mi->sta = sta;
ec8aa669
FF		 876 mi->stats_update = jiffies;
877
438b61b7
SW		 878 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
879 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
880 mi->overhead += ack_dur;
ec8aa669
FF		 881 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
882
883 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
884
885 /* When using MRR, sample more on the first attempt, without delay */
886 if (mp->has_mrr) {
887 mi->sample_count = 16;
888 mi->sample_wait = 0;
889 } else {
890 mi->sample_count = 8;
891 mi->sample_wait = 8;
892 }
893 mi->sample_tries = 4;
894
895 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
896 IEEE80211_HT_CAP_RX_STBC_SHIFT;
897 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
898
899 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
900 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
901
ec8aa669 902 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
ec8aa669 903 mi->groups[i].supported = 0;
a0497f9f
FF		 904 if (i == MINSTREL_CCK_GROUP) {
905 minstrel_ht_update_cck(mp, mi, sband, sta);
906 continue;
907 }
908
ec8aa669 909 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
e1a0c6b3
JB		 910 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
911 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
912 continue;
913 } else {
914 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
915 continue;
916 }
ec8aa669
FF		 917 }
918
e1a0c6b3
JB		 919 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
920 sta->bandwidth < IEEE80211_STA_RX_BW_40)
ec8aa669
FF		 921 continue;
922
e9219779 923 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
af0ed69b 924 if (sta->smps_mode == IEEE80211_SMPS_STATIC &&
e9219779
HS		 925 minstrel_mcs_groups[i].streams > 1)
926 continue;
927
ec8aa669
FF		 928 mi->groups[i].supported =
929 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
4dc217df
FF		 930
931 if (mi->groups[i].supported)
932 n_supported++;
ec8aa669 933 }
4dc217df
FF		 934
935 if (!n_supported)
936 goto use_legacy;
937
a8566662 938 /* create an initial rate table with the lowest supported rates */
a3647362 939 minstrel_ht_update_stats(mp, mi);
a8566662 940 minstrel_ht_update_rates(mp, mi);
a3647362 941
4dc217df
FF		 942 return;
943
944use_legacy:
945 msp->is_ht = false;
946 memset(&msp->legacy, 0, sizeof(msp->legacy));
947 msp->legacy.r = msp->ratelist;
948 msp->legacy.sample_table = msp->sample_table;
3de805cf
SW		 949 return mac80211_minstrel.rate_init(priv, sband, chandef, sta,
950 &msp->legacy);
ec8aa669
FF		 951}
952
953static void
954minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
3de805cf 955 struct cfg80211_chan_def *chandef,
ec8aa669
FF		 956 struct ieee80211_sta *sta, void *priv_sta)
957{
3de805cf 958 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
ec8aa669
FF		 959}
960
961static void
962minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
3de805cf 963 struct cfg80211_chan_def *chandef,
ec8aa669 964 struct ieee80211_sta *sta, void *priv_sta,
64f68e5d 965 u32 changed)
ec8aa669 966{
3de805cf 967 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
ec8aa669
FF		 968}
969
970static void *
971minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
972{
973 struct ieee80211_supported_band *sband;
974 struct minstrel_ht_sta_priv *msp;
975 struct minstrel_priv *mp = priv;
976 struct ieee80211_hw *hw = mp->hw;
977 int max_rates = 0;
978 int i;
979
980 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
981 sband = hw->wiphy->bands[i];
982 if (sband && sband->n_bitrates > max_rates)
983 max_rates = sband->n_bitrates;
984 }
985
472dd35c 986 msp = kzalloc(sizeof(*msp), gfp);
ec8aa669
FF		 987 if (!msp)
988 return NULL;
989
990 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
991 if (!msp->ratelist)
992 goto error;
993
994 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
995 if (!msp->sample_table)
996 goto error1;
997
998 return msp;
999
1000error1:
7e988014 1001 kfree(msp->ratelist);
ec8aa669
FF		 1002error:
1003 kfree(msp);
1004 return NULL;
1005}
1006
1007static void
1008minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1009{
1010 struct minstrel_ht_sta_priv *msp = priv_sta;
1011
1012 kfree(msp->sample_table);
1013 kfree(msp->ratelist);
1014 kfree(msp);
1015}
1016
1017static void *
1018minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
1019{
1020 return mac80211_minstrel.alloc(hw, debugfsdir);
1021}
1022
1023static void
1024minstrel_ht_free(void *priv)
1025{
1026 mac80211_minstrel.free(priv);
1027}
1028
1029static struct rate_control_ops mac80211_minstrel_ht = {
1030 .name = "minstrel_ht",
1031 .tx_status = minstrel_ht_tx_status,
1032 .get_rate = minstrel_ht_get_rate,
1033 .rate_init = minstrel_ht_rate_init,
1034 .rate_update = minstrel_ht_rate_update,
1035 .alloc_sta = minstrel_ht_alloc_sta,
1036 .free_sta = minstrel_ht_free_sta,
1037 .alloc = minstrel_ht_alloc,
1038 .free = minstrel_ht_free,
1039#ifdef CONFIG_MAC80211_DEBUGFS
1040 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
1041 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
1042#endif
1043};
1044
1045
1046static void
1047init_sample_table(void)
1048{
1049 int col, i, new_idx;
1050 u8 rnd[MCS_GROUP_RATES];
1051
1052 memset(sample_table, 0xff, sizeof(sample_table));
1053 for (col = 0; col < SAMPLE_COLUMNS; col++) {
1054 for (i = 0; i < MCS_GROUP_RATES; i++) {
1055 get_random_bytes(rnd, sizeof(rnd));
1056 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1057
1058 while (sample_table[col][new_idx] != 0xff)
1059 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1060
1061 sample_table[col][new_idx] = i;
1062 }
1063 }
1064}
1065
1066int __init
1067rc80211_minstrel_ht_init(void)
1068{
1069 init_sample_table();
1070 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1071}
1072
1073void
1074rc80211_minstrel_ht_exit(void)
1075{
1076 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
1077}
Linux kernel - Deliverables
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