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regulatory: allow VHT channels in world roaming
[GitHub/mt8127/android_kernel_alcatel_ttab.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
20#define SAMPLE_COLUMNS 10
21#define EWMA_LEVEL 75
22
23/* Number of bits for an average sized packet */
24#define MCS_NBITS (AVG_PKT_SIZE << 3)
25
26/* Number of symbols for a packet with (bps) bits per symbol */
27#define MCS_NSYMS(bps) ((MCS_NBITS + (bps) - 1) / (bps))
28
ed97a13c 29/* Transmission time (nanoseconds) for a packet containing (syms) symbols */
ec8aa669
FF		 30#define MCS_SYMBOL_TIME(sgi, syms) \
31 (sgi ? \
ed97a13c
FF		 32 ((syms) * 18000 + 4000) / 5 : /* syms * 3.6 us */ \
33 ((syms) * 1000) << 2 /* syms * 4 us */ \
ec8aa669
FF		 34 )
35
36/* Transmit duration for the raw data part of an average sized packet */
37#define MCS_DURATION(streams, sgi, bps) MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps)))
38
a5f69d94
HS		 39/*
40 * Define group sort order: HT40 -> SGI -> #streams
41 */
42#define GROUP_IDX(_streams, _sgi, _ht40) \
43 MINSTREL_MAX_STREAMS * 2 * _ht40 + \
44 MINSTREL_MAX_STREAMS * _sgi + \
45 _streams - 1
46
ec8aa669 47/* MCS rate information for an MCS group */
a5f69d94
HS		 48#define MCS_GROUP(_streams, _sgi, _ht40) \
49 [GROUP_IDX(_streams, _sgi, _ht40)] = { \
ec8aa669
FF		 50 .streams = _streams, \
51 .flags = \
52 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
53 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
54 .duration = { \
55 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \
56 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \
57 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \
58 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \
59 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \
60 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \
61 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \
62 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \
63 } \
64}
65
a0497f9f 66#define CCK_DURATION(_bitrate, _short, _len) \
ed97a13c 67 (1000 * (10 /* SIFS */ + \
a0497f9f 68 (_short ? 72 + 24 : 144 + 48 ) + \
ed97a13c 69 (8 * (_len + 4) * 10) / (_bitrate)))
a0497f9f
FF		 70
71#define CCK_ACK_DURATION(_bitrate, _short) \
72 (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) + \
73 CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))
74
75#define CCK_DURATION_LIST(_short) \
76 CCK_ACK_DURATION(10, _short), \
77 CCK_ACK_DURATION(20, _short), \
78 CCK_ACK_DURATION(55, _short), \
79 CCK_ACK_DURATION(110, _short)
80
81#define CCK_GROUP \
82 [MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS] = { \
83 .streams = 0, \
84 .duration = { \
85 CCK_DURATION_LIST(false), \
86 CCK_DURATION_LIST(true) \
87 } \
88 }
89
ec8aa669
FF		 90/*
91 * To enable sufficiently targeted rate sampling, MCS rates are divided into
92 * groups, based on the number of streams and flags (HT40, SGI) that they
93 * use.
a5f69d94
HS		 94 *
95 * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
96 * HT40 -> SGI -> #streams
ec8aa669
FF		 97 */
98const struct mcs_group minstrel_mcs_groups[] = {
99 MCS_GROUP(1, 0, 0),
100 MCS_GROUP(2, 0, 0),
101#if MINSTREL_MAX_STREAMS >= 3
102 MCS_GROUP(3, 0, 0),
103#endif
104
105 MCS_GROUP(1, 1, 0),
106 MCS_GROUP(2, 1, 0),
107#if MINSTREL_MAX_STREAMS >= 3
108 MCS_GROUP(3, 1, 0),
109#endif
110
111 MCS_GROUP(1, 0, 1),
112 MCS_GROUP(2, 0, 1),
113#if MINSTREL_MAX_STREAMS >= 3
114 MCS_GROUP(3, 0, 1),
115#endif
116
117 MCS_GROUP(1, 1, 1),
118 MCS_GROUP(2, 1, 1),
119#if MINSTREL_MAX_STREAMS >= 3
120 MCS_GROUP(3, 1, 1),
121#endif
a0497f9f
FF		 122
123 /* must be last */
124 CCK_GROUP
ec8aa669
FF		 125};
126
a0497f9f
FF		 127#define MINSTREL_CCK_GROUP (ARRAY_SIZE(minstrel_mcs_groups) - 1)
128
ec8aa669
FF		 129static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES];
130
131/*
132 * Perform EWMA (Exponentially Weighted Moving Average) calculation
133 */
134static int
135minstrel_ewma(int old, int new, int weight)
136{
137 return (new * (100 - weight) + old * weight) / 100;
138}
139
140/*
141 * Look up an MCS group index based on mac80211 rate information
142 */
143static int
144minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
145{
a5f69d94
HS		 146 return GROUP_IDX((rate->idx / MCS_GROUP_RATES) + 1,
147 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
148 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
ec8aa669
FF		 149}
150
a0497f9f
FF		 151static struct minstrel_rate_stats *
152minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
153 struct ieee80211_tx_rate *rate)
154{
155 int group, idx;
156
157 if (rate->flags & IEEE80211_TX_RC_MCS) {
158 group = minstrel_ht_get_group_idx(rate);
159 idx = rate->idx % MCS_GROUP_RATES;
160 } else {
161 group = MINSTREL_CCK_GROUP;
162
163 for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++)
164 if (rate->idx == mp->cck_rates[idx])
165 break;
166
167 /* short preamble */
168 if (!(mi->groups[group].supported & BIT(idx)))
169 idx += 4;
170 }
171 return &mi->groups[group].rates[idx];
172}
173
ec8aa669
FF		 174static inline struct minstrel_rate_stats *
175minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
176{
177 return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
178}
179
180
181/*
182 * Recalculate success probabilities and counters for a rate using EWMA
183 */
184static void
6048d763 185minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr)
ec8aa669
FF		 186{
187 if (unlikely(mr->attempts > 0)) {
188 mr->sample_skipped = 0;
189 mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
190 if (!mr->att_hist)
191 mr->probability = mr->cur_prob;
192 else
193 mr->probability = minstrel_ewma(mr->probability,
194 mr->cur_prob, EWMA_LEVEL);
195 mr->att_hist += mr->attempts;
196 mr->succ_hist += mr->success;
197 } else {
198 mr->sample_skipped++;
199 }
200 mr->last_success = mr->success;
201 mr->last_attempts = mr->attempts;
202 mr->success = 0;
203 mr->attempts = 0;
204}
205
206/*
207 * Calculate throughput based on the average A-MPDU length, taking into account
208 * the expected number of retransmissions and their expected length
209 */
210static void
6048d763 211minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
ec8aa669
FF		 212{
213 struct minstrel_rate_stats *mr;
ed97a13c
FF		 214 unsigned int nsecs = 0;
215 unsigned int tp;
ec8aa669
FF		 216
217 mr = &mi->groups[group].rates[rate];
218
219 if (mr->probability < MINSTREL_FRAC(1, 10)) {
220 mr->cur_tp = 0;
221 return;
222 }
223
a0497f9f 224 if (group != MINSTREL_CCK_GROUP)
ed97a13c 225 nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
a0497f9f 226
ed97a13c
FF		 227 nsecs += minstrel_mcs_groups[group].duration[rate];
228 tp = 1000000 * ((mr->probability * 1000) / nsecs);
229
230 mr->cur_tp = MINSTREL_TRUNC(tp);
ec8aa669
FF		 231}
232
233/*
234 * Update rate statistics and select new primary rates
235 *
236 * Rules for rate selection:
237 * - max_prob_rate must use only one stream, as a tradeoff between delivery
238 * probability and throughput during strong fluctuations
239 * - as long as the max prob rate has a probability of more than 3/4, pick
240 * higher throughput rates, even if the probablity is a bit lower
241 */
242static void
243minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
244{
245 struct minstrel_mcs_group_data *mg;
246 struct minstrel_rate_stats *mr;
247 int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
248 int group, i, index;
249
250 if (mi->ampdu_packets > 0) {
251 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
252 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
253 mi->ampdu_len = 0;
254 mi->ampdu_packets = 0;
255 }
256
257 mi->sample_slow = 0;
258 mi->sample_count = 0;
259 mi->max_tp_rate = 0;
260 mi->max_tp_rate2 = 0;
261 mi->max_prob_rate = 0;
262
263 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
264 cur_prob = 0;
265 cur_prob_tp = 0;
266 cur_tp = 0;
267 cur_tp2 = 0;
268
269 mg = &mi->groups[group];
270 if (!mg->supported)
271 continue;
272
273 mg->max_tp_rate = 0;
274 mg->max_tp_rate2 = 0;
275 mg->max_prob_rate = 0;
276 mi->sample_count++;
277
278 for (i = 0; i < MCS_GROUP_RATES; i++) {
279 if (!(mg->supported & BIT(i)))
280 continue;
281
282 mr = &mg->rates[i];
283 mr->retry_updated = false;
284 index = MCS_GROUP_RATES * group + i;
6048d763
PK		 285 minstrel_calc_rate_ewma(mr);
286 minstrel_ht_calc_tp(mi, group, i);
ec8aa669
FF		 287
288 if (!mr->cur_tp)
289 continue;
290
ec8aa669
FF		 291 if ((mr->cur_tp > cur_prob_tp && mr->probability >
292 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
293 mg->max_prob_rate = index;
294 cur_prob = mr->probability;
009271f9 295 cur_prob_tp = mr->cur_tp;
ec8aa669
FF		 296 }
297
298 if (mr->cur_tp > cur_tp) {
299 swap(index, mg->max_tp_rate);
300 cur_tp = mr->cur_tp;
301 mr = minstrel_get_ratestats(mi, index);
302 }
303
304 if (index >= mg->max_tp_rate)
305 continue;
306
307 if (mr->cur_tp > cur_tp2) {
308 mg->max_tp_rate2 = index;
309 cur_tp2 = mr->cur_tp;
310 }
311 }
312 }
313
96d4ac3f
FF		 314 /* try to sample all available rates during each interval */
315 mi->sample_count *= 8;
ec8aa669
FF		 316
317 cur_prob = 0;
318 cur_prob_tp = 0;
319 cur_tp = 0;
320 cur_tp2 = 0;
321 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
322 mg = &mi->groups[group];
323 if (!mg->supported)
324 continue;
325
ec8aa669
FF		 326 mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
327 if (cur_tp < mr->cur_tp) {
89888e36
LB		 328 mi->max_tp_rate2 = mi->max_tp_rate;
329 cur_tp2 = cur_tp;
ec8aa669
FF		 330 mi->max_tp_rate = mg->max_tp_rate;
331 cur_tp = mr->cur_tp;
965237ab 332 mi->max_prob_streams = minstrel_mcs_groups[group].streams - 1;
ec8aa669
FF		 333 }
334
335 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
336 if (cur_tp2 < mr->cur_tp) {
337 mi->max_tp_rate2 = mg->max_tp_rate2;
338 cur_tp2 = mr->cur_tp;
339 }
340 }
341
965237ab
FF		 342 if (mi->max_prob_streams < 1)
343 mi->max_prob_streams = 1;
a299c6d5
FF		 344
345 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
346 mg = &mi->groups[group];
347 if (!mg->supported)
348 continue;
349 mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
350 if (cur_prob_tp < mr->cur_tp &&
965237ab 351 minstrel_mcs_groups[group].streams <= mi->max_prob_streams) {
a299c6d5
FF		 352 mi->max_prob_rate = mg->max_prob_rate;
353 cur_prob = mr->cur_prob;
354 cur_prob_tp = mr->cur_tp;
355 }
356 }
357
358
ec8aa669
FF		 359 mi->stats_update = jiffies;
360}
361
362static bool
a0497f9f 363minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
ec8aa669 364{
b79296be 365 if (rate->idx < 0)
ec8aa669
FF		 366 return false;
367
b79296be 368 if (!rate->count)
ec8aa669
FF		 369 return false;
370
a0497f9f
FF		 371 if (rate->flags & IEEE80211_TX_RC_MCS)
372 return true;
373
374 return rate->idx == mp->cck_rates[0] ||
375 rate->idx == mp->cck_rates[1] ||
376 rate->idx == mp->cck_rates[2] ||
377 rate->idx == mp->cck_rates[3];
ec8aa669
FF		 378}
379
380static void
381minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
382{
383 struct minstrel_mcs_group_data *mg;
384
385 for (;;) {
386 mi->sample_group++;
387 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
388 mg = &mi->groups[mi->sample_group];
389
390 if (!mg->supported)
391 continue;
392
393 if (++mg->index >= MCS_GROUP_RATES) {
394 mg->index = 0;
395 if (++mg->column >= ARRAY_SIZE(sample_table))
396 mg->column = 0;
397 }
398 break;
399 }
400}
401
402static void
d5ece215
JL		 403minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx,
404 bool primary)
ec8aa669
FF		 405{
406 int group, orig_group;
407
408 orig_group = group = *idx / MCS_GROUP_RATES;
409 while (group > 0) {
410 group--;
411
412 if (!mi->groups[group].supported)
413 continue;
414
415 if (minstrel_mcs_groups[group].streams >
416 minstrel_mcs_groups[orig_group].streams)
417 continue;
418
419 if (primary)
420 *idx = mi->groups[group].max_tp_rate;
421 else
422 *idx = mi->groups[group].max_tp_rate2;
423 break;
424 }
425}
426
427static void
6048d763 428minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
ec8aa669
FF		 429{
430 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
431 struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
432 u16 tid;
433
434 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
435 return;
436
437 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
438 return;
439
440 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
a622ab72 441 if (likely(sta->ampdu_mlme.tid_tx[tid]))
ec8aa669
FF		 442 return;
443
48124d1a
LR		 444 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
445 return;
446
bd2ce6e4 447 ieee80211_start_tx_ba_session(pubsta, tid, 5000);
ec8aa669
FF		 448}
449
450static void
451minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
452 struct ieee80211_sta *sta, void *priv_sta,
453 struct sk_buff *skb)
454{
455 struct minstrel_ht_sta_priv *msp = priv_sta;
456 struct minstrel_ht_sta *mi = &msp->ht;
457 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
458 struct ieee80211_tx_rate *ar = info->status.rates;
459 struct minstrel_rate_stats *rate, *rate2;
460 struct minstrel_priv *mp = priv;
a544ab7f 461 bool last;
a544ab7f 462 int i;
ec8aa669
FF		 463
464 if (!msp->is_ht)
465 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
466
467 /* This packet was aggregated but doesn't carry status info */
468 if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
469 !(info->flags & IEEE80211_TX_STAT_AMPDU))
470 return;
471
15d46f38
BS		 472 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
473 info->status.ampdu_ack_len =
474 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
ec8aa669
FF		 475 info->status.ampdu_len = 1;
476 }
477
478 mi->ampdu_packets++;
479 mi->ampdu_len += info->status.ampdu_len;
480
481 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
c7317e41
FF		 482 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
483 mi->sample_tries = 2;
ec8aa669
FF		 484 mi->sample_count--;
485 }
486
8d5eab5a 487 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
ec8aa669 488 mi->sample_packets += info->status.ampdu_len;
ec8aa669 489
a0497f9f 490 last = !minstrel_ht_txstat_valid(mp, &ar[0]);
ec8aa669
FF		 491 for (i = 0; !last; i++) {
492 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
a0497f9f 493 !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
ec8aa669 494
a0497f9f 495 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
ec8aa669 496
15d46f38 497 if (last)
ec8aa669
FF		 498 rate->success += info->status.ampdu_ack_len;
499
500 rate->attempts += ar[i].count * info->status.ampdu_len;
501 }
502
503 /*
504 * check for sudden death of spatial multiplexing,
505 * downgrade to a lower number of streams if necessary.
506 */
507 rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
508 if (rate->attempts > 30 &&
509 MINSTREL_FRAC(rate->success, rate->attempts) <
510 MINSTREL_FRAC(20, 100))
511 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
512
513 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
ecc3d5ae
ML		 514 if (rate2->attempts > 30 &&
515 MINSTREL_FRAC(rate2->success, rate2->attempts) <
ec8aa669
FF		 516 MINSTREL_FRAC(20, 100))
517 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
518
519 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
520 minstrel_ht_update_stats(mp, mi);
a0497f9f
FF		 521 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
522 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
6048d763 523 minstrel_aggr_check(sta, skb);
ec8aa669
FF		 524 }
525}
526
527static void
528minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
529 int index)
530{
531 struct minstrel_rate_stats *mr;
532 const struct mcs_group *group;
533 unsigned int tx_time, tx_time_rtscts, tx_time_data;
534 unsigned int cw = mp->cw_min;
8fddddff 535 unsigned int ctime = 0;
ec8aa669
FF		 536 unsigned int t_slot = 9; /* FIXME */
537 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
a0497f9f 538 unsigned int overhead = 0, overhead_rtscts = 0;
ec8aa669
FF		 539
540 mr = minstrel_get_ratestats(mi, index);
541 if (mr->probability < MINSTREL_FRAC(1, 10)) {
542 mr->retry_count = 1;
543 mr->retry_count_rtscts = 1;
544 return;
545 }
546
547 mr->retry_count = 2;
548 mr->retry_count_rtscts = 2;
549 mr->retry_updated = true;
550
551 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
ed97a13c 552 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
8fddddff
DH		 553
554 /* Contention time for first 2 tries */
555 ctime = (t_slot * cw) >> 1;
556 cw = min((cw << 1) | 1, mp->cw_max);
557 ctime += (t_slot * cw) >> 1;
558 cw = min((cw << 1) | 1, mp->cw_max);
559
a0497f9f
FF		 560 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
561 overhead = mi->overhead;
562 overhead_rtscts = mi->overhead_rtscts;
563 }
564
8fddddff 565 /* Total TX time for data and Contention after first 2 tries */
a0497f9f
FF		 566 tx_time = ctime + 2 * (overhead + tx_time_data);
567 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
8fddddff
DH		 568
569 /* See how many more tries we can fit inside segment size */
ec8aa669 570 do {
8fddddff
DH		 571 /* Contention time for this try */
572 ctime = (t_slot * cw) >> 1;
573 cw = min((cw << 1) | 1, mp->cw_max);
574
575 /* Total TX time after this try */
a0497f9f
FF		 576 tx_time += ctime + overhead + tx_time_data;
577 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
8fddddff 578
ec8aa669
FF		 579 if (tx_time_rtscts < mp->segment_size)
580 mr->retry_count_rtscts++;
581 } while ((tx_time < mp->segment_size) &&
582 (++mr->retry_count < mp->max_retry));
583}
584
585
586static void
587minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
588 struct ieee80211_tx_rate *rate, int index,
ec8aa669
FF		 589 bool sample, bool rtscts)
590{
591 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
592 struct minstrel_rate_stats *mr;
593
594 mr = minstrel_get_ratestats(mi, index);
595 if (!mr->retry_updated)
596 minstrel_calc_retransmit(mp, mi, index);
597
c7317e41
FF		 598 if (sample)
599 rate->count = 1;
600 else if (mr->probability < MINSTREL_FRAC(20, 100))
ec8aa669
FF		 601 rate->count = 2;
602 else if (rtscts)
603 rate->count = mr->retry_count_rtscts;
604 else
605 rate->count = mr->retry_count;
606
a0497f9f 607 rate->flags = 0;
9d468d22 608 if (rtscts)
ec8aa669 609 rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS;
a0497f9f
FF		 610
611 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
612 rate->idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
613 return;
614 }
615
616 rate->flags |= IEEE80211_TX_RC_MCS | group->flags;
ec8aa669
FF		 617 rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES;
618}
619
620static inline int
621minstrel_get_duration(int index)
622{
623 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
624 return group->duration[index % MCS_GROUP_RATES];
625}
626
627static int
628minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
629{
630 struct minstrel_rate_stats *mr;
631 struct minstrel_mcs_group_data *mg;
965237ab 632 unsigned int sample_dur, sample_group;
ec8aa669
FF		 633 int sample_idx = 0;
634
635 if (mi->sample_wait > 0) {
636 mi->sample_wait--;
637 return -1;
638 }
639
640 if (!mi->sample_tries)
641 return -1;
642
ec8aa669
FF		 643 mg = &mi->groups[mi->sample_group];
644 sample_idx = sample_table[mg->column][mg->index];
645 mr = &mg->rates[sample_idx];
965237ab
FF		 646 sample_group = mi->sample_group;
647 sample_idx += sample_group * MCS_GROUP_RATES;
8d5eab5a 648 minstrel_next_sample_idx(mi);
ec8aa669 649
ba6fa29c
HS		 650 /*
651 * Sampling might add some overhead (RTS, no aggregation)
652 * to the frame. Hence, don't use sampling for the currently
653 * used max TP rate.
654 */
655 if (sample_idx == mi->max_tp_rate)
656 return -1;
ec8aa669
FF		 657 /*
658 * When not using MRR, do not sample if the probability is already
659 * higher than 95% to avoid wasting airtime
660 */
661 if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100)))
8d5eab5a 662 return -1;
ec8aa669
FF		 663
664 /*
665 * Make sure that lower rates get sampled only occasionally,
666 * if the link is working perfectly.
667 */
965237ab
FF		 668 sample_dur = minstrel_get_duration(sample_idx);
669 if (sample_dur >= minstrel_get_duration(mi->max_tp_rate2) &&
670 (mi->max_prob_streams <
671 minstrel_mcs_groups[sample_group].streams ||
672 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
c7317e41 673 if (mr->sample_skipped < 20)
8d5eab5a 674 return -1;
ec8aa669
FF		 675
676 if (mi->sample_slow++ > 2)
8d5eab5a 677 return -1;
ec8aa669 678 }
098b8afb 679 mi->sample_tries--;
ec8aa669
FF		 680
681 return sample_idx;
ec8aa669
FF		 682}
683
a0497f9f
FF		 684static void
685minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp,
686 struct minstrel_ht_sta *mi, bool val)
687{
688 u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported;
689
690 if (!supported || !mi->cck_supported_short)
691 return;
692
693 if (supported & (mi->cck_supported_short << (val * 4)))
694 return;
695
696 supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4);
697 mi->groups[MINSTREL_CCK_GROUP].supported = supported;
698}
699
ec8aa669
FF		 700static void
701minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
702 struct ieee80211_tx_rate_control *txrc)
703{
704 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
705 struct ieee80211_tx_rate *ar = info->status.rates;
706 struct minstrel_ht_sta_priv *msp = priv_sta;
707 struct minstrel_ht_sta *mi = &msp->ht;
708 struct minstrel_priv *mp = priv;
709 int sample_idx;
c7317e41 710 bool sample = false;
ec8aa669
FF		 711
712 if (rate_control_send_low(sta, priv_sta, txrc))
713 return;
714
715 if (!msp->is_ht)
716 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
717
718 info->flags |= mi->tx_flags;
a0497f9f 719 minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble);
6de062ce
HS		 720
721 /* Don't use EAPOL frames for sampling on non-mrr hw */
722 if (mp->hw->max_rates == 1 &&
723 txrc->skb->protocol == cpu_to_be16(ETH_P_PAE))
724 sample_idx = -1;
725 else
726 sample_idx = minstrel_get_sample_rate(mp, mi);
24f7580e
ZK		 727
728#ifdef CONFIG_MAC80211_DEBUGFS
729 /* use fixed index if set */
2a9e6c58
SRR		 730 if (mp->fixed_rate_idx != -1) {
731 mi->max_tp_rate = mp->fixed_rate_idx;
732 mi->max_tp_rate2 = mp->fixed_rate_idx;
733 mi->max_prob_rate = mp->fixed_rate_idx;
734 sample_idx = -1;
735 }
24f7580e
ZK		 736#endif
737
ec8aa669 738 if (sample_idx >= 0) {
c7317e41 739 sample = true;
ec8aa669 740 minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
6048d763 741 true, false);
ec8aa669
FF		 742 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
743 } else {
744 minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
6048d763 745 false, false);
ec8aa669 746 }
ec8aa669 747
cf28d793
HS		 748 if (mp->hw->max_rates >= 3) {
749 /*
750 * At least 3 tx rates supported, use
751 * sample_rate -> max_tp_rate -> max_prob_rate for sampling and
752 * max_tp_rate -> max_tp_rate2 -> max_prob_rate by default.
753 */
754 if (sample_idx >= 0)
755 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
6048d763 756 false, false);
cf28d793
HS		 757 else
758 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2,
6048d763 759 false, true);
cf28d793
HS		 760
761 minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate,
6048d763 762 false, !sample);
cf28d793
HS		 763
764 ar[3].count = 0;
765 ar[3].idx = -1;
766 } else if (mp->hw->max_rates == 2) {
767 /*
768 * Only 2 tx rates supported, use
769 * sample_rate -> max_prob_rate for sampling and
770 * max_tp_rate -> max_prob_rate by default.
771 */
772 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_prob_rate,
6048d763 773 false, !sample);
cf28d793
HS		 774
775 ar[2].count = 0;
776 ar[2].idx = -1;
777 } else {
778 /* Not using MRR, only use the first rate */
779 ar[1].count = 0;
780 ar[1].idx = -1;
781 }
ec8aa669
FF		 782
783 mi->total_packets++;
784
785 /* wraparound */
786 if (mi->total_packets == ~0) {
787 mi->total_packets = 0;
788 mi->sample_packets = 0;
789 }
790}
791
a0497f9f
FF		 792static void
793minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
794 struct ieee80211_supported_band *sband,
795 struct ieee80211_sta *sta)
796{
797 int i;
798
799 if (sband->band != IEEE80211_BAND_2GHZ)
800 return;
801
802 mi->cck_supported = 0;
803 mi->cck_supported_short = 0;
804 for (i = 0; i < 4; i++) {
805 if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
806 continue;
807
808 mi->cck_supported |= BIT(i);
809 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
810 mi->cck_supported_short |= BIT(i);
811 }
812
813 mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported;
814}
815
ec8aa669
FF		 816static void
817minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
64f68e5d 818 struct ieee80211_sta *sta, void *priv_sta)
ec8aa669
FF		 819{
820 struct minstrel_priv *mp = priv;
821 struct minstrel_ht_sta_priv *msp = priv_sta;
822 struct minstrel_ht_sta *mi = &msp->ht;
823 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
ec8aa669 824 u16 sta_cap = sta->ht_cap.cap;
4dc217df 825 int n_supported = 0;
ec8aa669
FF		 826 int ack_dur;
827 int stbc;
828 int i;
829
830 /* fall back to the old minstrel for legacy stations */
4dc217df
FF		 831 if (!sta->ht_cap.ht_supported)
832 goto use_legacy;
ec8aa669
FF		 833
834 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
a0497f9f 835 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1);
ec8aa669
FF		 836
837 msp->is_ht = true;
838 memset(mi, 0, sizeof(*mi));
839 mi->stats_update = jiffies;
840
4ee73f33
MK		 841 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1);
842 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1) + ack_dur;
ec8aa669
FF		 843 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
844
845 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
846
847 /* When using MRR, sample more on the first attempt, without delay */
848 if (mp->has_mrr) {
849 mi->sample_count = 16;
850 mi->sample_wait = 0;
851 } else {
852 mi->sample_count = 8;
853 mi->sample_wait = 8;
854 }
855 mi->sample_tries = 4;
856
857 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
858 IEEE80211_HT_CAP_RX_STBC_SHIFT;
859 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
860
861 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
862 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
863
ec8aa669 864 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
ec8aa669 865 mi->groups[i].supported = 0;
a0497f9f
FF		 866 if (i == MINSTREL_CCK_GROUP) {
867 minstrel_ht_update_cck(mp, mi, sband, sta);
868 continue;
869 }
870
ec8aa669 871 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
e1a0c6b3
JB		 872 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
873 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
874 continue;
875 } else {
876 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
877 continue;
878 }
ec8aa669
FF		 879 }
880
e1a0c6b3
JB		 881 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
882 sta->bandwidth < IEEE80211_STA_RX_BW_40)
ec8aa669
FF		 883 continue;
884
e9219779 885 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
af0ed69b 886 if (sta->smps_mode == IEEE80211_SMPS_STATIC &&
e9219779
HS		 887 minstrel_mcs_groups[i].streams > 1)
888 continue;
889
ec8aa669
FF		 890 mi->groups[i].supported =
891 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
4dc217df
FF		 892
893 if (mi->groups[i].supported)
894 n_supported++;
ec8aa669 895 }
4dc217df
FF		 896
897 if (!n_supported)
898 goto use_legacy;
899
900 return;
901
902use_legacy:
903 msp->is_ht = false;
904 memset(&msp->legacy, 0, sizeof(msp->legacy));
905 msp->legacy.r = msp->ratelist;
906 msp->legacy.sample_table = msp->sample_table;
907 return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy);
ec8aa669
FF		 908}
909
910static void
911minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
912 struct ieee80211_sta *sta, void *priv_sta)
913{
64f68e5d 914 minstrel_ht_update_caps(priv, sband, sta, priv_sta);
ec8aa669
FF		 915}
916
917static void
918minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
919 struct ieee80211_sta *sta, void *priv_sta,
64f68e5d 920 u32 changed)
ec8aa669 921{
64f68e5d 922 minstrel_ht_update_caps(priv, sband, sta, priv_sta);
ec8aa669
FF		 923}
924
925static void *
926minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
927{
928 struct ieee80211_supported_band *sband;
929 struct minstrel_ht_sta_priv *msp;
930 struct minstrel_priv *mp = priv;
931 struct ieee80211_hw *hw = mp->hw;
932 int max_rates = 0;
933 int i;
934
935 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
936 sband = hw->wiphy->bands[i];
937 if (sband && sband->n_bitrates > max_rates)
938 max_rates = sband->n_bitrates;
939 }
940
472dd35c 941 msp = kzalloc(sizeof(*msp), gfp);
ec8aa669
FF		 942 if (!msp)
943 return NULL;
944
945 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
946 if (!msp->ratelist)
947 goto error;
948
949 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
950 if (!msp->sample_table)
951 goto error1;
952
953 return msp;
954
955error1:
7e988014 956 kfree(msp->ratelist);
ec8aa669
FF		 957error:
958 kfree(msp);
959 return NULL;
960}
961
962static void
963minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
964{
965 struct minstrel_ht_sta_priv *msp = priv_sta;
966
967 kfree(msp->sample_table);
968 kfree(msp->ratelist);
969 kfree(msp);
970}
971
972static void *
973minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
974{
975 return mac80211_minstrel.alloc(hw, debugfsdir);
976}
977
978static void
979minstrel_ht_free(void *priv)
980{
981 mac80211_minstrel.free(priv);
982}
983
984static struct rate_control_ops mac80211_minstrel_ht = {
985 .name = "minstrel_ht",
986 .tx_status = minstrel_ht_tx_status,
987 .get_rate = minstrel_ht_get_rate,
988 .rate_init = minstrel_ht_rate_init,
989 .rate_update = minstrel_ht_rate_update,
990 .alloc_sta = minstrel_ht_alloc_sta,
991 .free_sta = minstrel_ht_free_sta,
992 .alloc = minstrel_ht_alloc,
993 .free = minstrel_ht_free,
994#ifdef CONFIG_MAC80211_DEBUGFS
995 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
996 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
997#endif
998};
999
1000
1001static void
1002init_sample_table(void)
1003{
1004 int col, i, new_idx;
1005 u8 rnd[MCS_GROUP_RATES];
1006
1007 memset(sample_table, 0xff, sizeof(sample_table));
1008 for (col = 0; col < SAMPLE_COLUMNS; col++) {
1009 for (i = 0; i < MCS_GROUP_RATES; i++) {
1010 get_random_bytes(rnd, sizeof(rnd));
1011 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1012
1013 while (sample_table[col][new_idx] != 0xff)
1014 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1015
1016 sample_table[col][new_idx] = i;
1017 }
1018 }
1019}
1020
1021int __init
1022rc80211_minstrel_ht_init(void)
1023{
1024 init_sample_table();
1025 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1026}
1027
1028void
1029rc80211_minstrel_ht_exit(void)
1030{
1031 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
1032}
kernel source for telekom puls (alcatel/mediatek)