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Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6
[net-next-2.6.git] / net / mac80211 / rc80211_minstrel_ht.c
CommitLineData
ec8aa669
FF		 1/*
2 * Copyright (C) 2010 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/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
29/* Transmission time for a packet containing (syms) symbols */
30#define MCS_SYMBOL_TIME(sgi, syms) \
31 (sgi ? \
32 ((syms) * 18 + 4) / 5 : /* syms * 3.6 us */ \
33 (syms) << 2 /* syms * 4 us */ \
34 )
35
36/* Transmit duration for the raw data part of an average sized packet */
37#define MCS_DURATION(streams, sgi, bps) MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps)))
38
39/* MCS rate information for an MCS group */
40#define MCS_GROUP(_streams, _sgi, _ht40) { \
41 .streams = _streams, \
42 .flags = \
43 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
44 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
45 .duration = { \
46 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \
47 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \
48 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \
49 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \
50 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \
51 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \
52 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \
53 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \
54 } \
55}
56
57/*
58 * To enable sufficiently targeted rate sampling, MCS rates are divided into
59 * groups, based on the number of streams and flags (HT40, SGI) that they
60 * use.
61 */
62const struct mcs_group minstrel_mcs_groups[] = {
63 MCS_GROUP(1, 0, 0),
64 MCS_GROUP(2, 0, 0),
65#if MINSTREL_MAX_STREAMS >= 3
66 MCS_GROUP(3, 0, 0),
67#endif
68
69 MCS_GROUP(1, 1, 0),
70 MCS_GROUP(2, 1, 0),
71#if MINSTREL_MAX_STREAMS >= 3
72 MCS_GROUP(3, 1, 0),
73#endif
74
75 MCS_GROUP(1, 0, 1),
76 MCS_GROUP(2, 0, 1),
77#if MINSTREL_MAX_STREAMS >= 3
78 MCS_GROUP(3, 0, 1),
79#endif
80
81 MCS_GROUP(1, 1, 1),
82 MCS_GROUP(2, 1, 1),
83#if MINSTREL_MAX_STREAMS >= 3
84 MCS_GROUP(3, 1, 1),
85#endif
86};
87
88static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES];
89
90/*
91 * Perform EWMA (Exponentially Weighted Moving Average) calculation
92 */
93static int
94minstrel_ewma(int old, int new, int weight)
95{
96 return (new * (100 - weight) + old * weight) / 100;
97}
98
99/*
100 * Look up an MCS group index based on mac80211 rate information
101 */
102static int
103minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
104{
105 int streams = (rate->idx / MCS_GROUP_RATES) + 1;
106 u32 flags = IEEE80211_TX_RC_SHORT_GI | IEEE80211_TX_RC_40_MHZ_WIDTH;
107 int i;
108
109 for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) {
110 if (minstrel_mcs_groups[i].streams != streams)
111 continue;
112 if (minstrel_mcs_groups[i].flags != (rate->flags & flags))
113 continue;
114
115 return i;
116 }
117
118 WARN_ON(1);
119 return 0;
120}
121
122static inline struct minstrel_rate_stats *
123minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
124{
125 return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
126}
127
128
129/*
130 * Recalculate success probabilities and counters for a rate using EWMA
131 */
132static void
133minstrel_calc_rate_ewma(struct minstrel_priv *mp, struct minstrel_rate_stats *mr)
134{
135 if (unlikely(mr->attempts > 0)) {
136 mr->sample_skipped = 0;
137 mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
138 if (!mr->att_hist)
139 mr->probability = mr->cur_prob;
140 else
141 mr->probability = minstrel_ewma(mr->probability,
142 mr->cur_prob, EWMA_LEVEL);
143 mr->att_hist += mr->attempts;
144 mr->succ_hist += mr->success;
145 } else {
146 mr->sample_skipped++;
147 }
148 mr->last_success = mr->success;
149 mr->last_attempts = mr->attempts;
150 mr->success = 0;
151 mr->attempts = 0;
152}
153
154/*
155 * Calculate throughput based on the average A-MPDU length, taking into account
156 * the expected number of retransmissions and their expected length
157 */
158static void
159minstrel_ht_calc_tp(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
160 int group, int rate)
161{
162 struct minstrel_rate_stats *mr;
163 unsigned int usecs;
164
165 mr = &mi->groups[group].rates[rate];
166
167 if (mr->probability < MINSTREL_FRAC(1, 10)) {
168 mr->cur_tp = 0;
169 return;
170 }
171
172 usecs = mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
173 usecs += minstrel_mcs_groups[group].duration[rate];
174 mr->cur_tp = MINSTREL_TRUNC((1000000 / usecs) * mr->probability);
175}
176
177/*
178 * Update rate statistics and select new primary rates
179 *
180 * Rules for rate selection:
181 * - max_prob_rate must use only one stream, as a tradeoff between delivery
182 * probability and throughput during strong fluctuations
183 * - as long as the max prob rate has a probability of more than 3/4, pick
184 * higher throughput rates, even if the probablity is a bit lower
185 */
186static void
187minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
188{
189 struct minstrel_mcs_group_data *mg;
190 struct minstrel_rate_stats *mr;
191 int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
192 int group, i, index;
193
194 if (mi->ampdu_packets > 0) {
195 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
196 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
197 mi->ampdu_len = 0;
198 mi->ampdu_packets = 0;
199 }
200
201 mi->sample_slow = 0;
202 mi->sample_count = 0;
203 mi->max_tp_rate = 0;
204 mi->max_tp_rate2 = 0;
205 mi->max_prob_rate = 0;
206
207 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
208 cur_prob = 0;
209 cur_prob_tp = 0;
210 cur_tp = 0;
211 cur_tp2 = 0;
212
213 mg = &mi->groups[group];
214 if (!mg->supported)
215 continue;
216
217 mg->max_tp_rate = 0;
218 mg->max_tp_rate2 = 0;
219 mg->max_prob_rate = 0;
220 mi->sample_count++;
221
222 for (i = 0; i < MCS_GROUP_RATES; i++) {
223 if (!(mg->supported & BIT(i)))
224 continue;
225
226 mr = &mg->rates[i];
227 mr->retry_updated = false;
228 index = MCS_GROUP_RATES * group + i;
229 minstrel_calc_rate_ewma(mp, mr);
230 minstrel_ht_calc_tp(mp, mi, group, i);
231
232 if (!mr->cur_tp)
233 continue;
234
235 /* ignore the lowest rate of each single-stream group */
236 if (!i && minstrel_mcs_groups[group].streams == 1)
237 continue;
238
239 if ((mr->cur_tp > cur_prob_tp && mr->probability >
240 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
241 mg->max_prob_rate = index;
242 cur_prob = mr->probability;
009271f9 243 cur_prob_tp = mr->cur_tp;
ec8aa669
FF		 244 }
245
246 if (mr->cur_tp > cur_tp) {
247 swap(index, mg->max_tp_rate);
248 cur_tp = mr->cur_tp;
249 mr = minstrel_get_ratestats(mi, index);
250 }
251
252 if (index >= mg->max_tp_rate)
253 continue;
254
255 if (mr->cur_tp > cur_tp2) {
256 mg->max_tp_rate2 = index;
257 cur_tp2 = mr->cur_tp;
258 }
259 }
260 }
261
262 /* try to sample up to half of the availble rates during each interval */
263 mi->sample_count *= 4;
264
265 cur_prob = 0;
266 cur_prob_tp = 0;
267 cur_tp = 0;
268 cur_tp2 = 0;
269 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
270 mg = &mi->groups[group];
271 if (!mg->supported)
272 continue;
273
274 mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
275 if (cur_prob_tp < mr->cur_tp &&
276 minstrel_mcs_groups[group].streams == 1) {
277 mi->max_prob_rate = mg->max_prob_rate;
278 cur_prob = mr->cur_prob;
009271f9 279 cur_prob_tp = mr->cur_tp;
ec8aa669
FF		 280 }
281
282 mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
283 if (cur_tp < mr->cur_tp) {
284 mi->max_tp_rate = mg->max_tp_rate;
285 cur_tp = mr->cur_tp;
286 }
287
288 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
289 if (cur_tp2 < mr->cur_tp) {
290 mi->max_tp_rate2 = mg->max_tp_rate2;
291 cur_tp2 = mr->cur_tp;
292 }
293 }
294
295 mi->stats_update = jiffies;
296}
297
298static bool
299minstrel_ht_txstat_valid(struct ieee80211_tx_rate *rate)
300{
301 if (!rate->count)
302 return false;
303
304 if (rate->idx < 0)
305 return false;
306
307 return !!(rate->flags & IEEE80211_TX_RC_MCS);
308}
309
310static void
311minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
312{
313 struct minstrel_mcs_group_data *mg;
314
315 for (;;) {
316 mi->sample_group++;
317 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
318 mg = &mi->groups[mi->sample_group];
319
320 if (!mg->supported)
321 continue;
322
323 if (++mg->index >= MCS_GROUP_RATES) {
324 mg->index = 0;
325 if (++mg->column >= ARRAY_SIZE(sample_table))
326 mg->column = 0;
327 }
328 break;
329 }
330}
331
332static void
d5ece215
JL		 333minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx,
334 bool primary)
ec8aa669
FF		 335{
336 int group, orig_group;
337
338 orig_group = group = *idx / MCS_GROUP_RATES;
339 while (group > 0) {
340 group--;
341
342 if (!mi->groups[group].supported)
343 continue;
344
345 if (minstrel_mcs_groups[group].streams >
346 minstrel_mcs_groups[orig_group].streams)
347 continue;
348
349 if (primary)
350 *idx = mi->groups[group].max_tp_rate;
351 else
352 *idx = mi->groups[group].max_tp_rate2;
353 break;
354 }
355}
356
357static void
358minstrel_aggr_check(struct minstrel_priv *mp, struct ieee80211_sta *pubsta, struct sk_buff *skb)
359{
360 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
361 struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
362 u16 tid;
363
364 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
365 return;
366
367 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
368 return;
369
370 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
a622ab72 371 if (likely(sta->ampdu_mlme.tid_tx[tid]))
ec8aa669
FF		 372 return;
373
374 ieee80211_start_tx_ba_session(pubsta, tid);
375}
376
377static void
378minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
379 struct ieee80211_sta *sta, void *priv_sta,
380 struct sk_buff *skb)
381{
382 struct minstrel_ht_sta_priv *msp = priv_sta;
383 struct minstrel_ht_sta *mi = &msp->ht;
384 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
385 struct ieee80211_tx_rate *ar = info->status.rates;
386 struct minstrel_rate_stats *rate, *rate2;
387 struct minstrel_priv *mp = priv;
388 bool last = false;
389 int group;
390 int i = 0;
391
392 if (!msp->is_ht)
393 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
394
395 /* This packet was aggregated but doesn't carry status info */
396 if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
397 !(info->flags & IEEE80211_TX_STAT_AMPDU))
398 return;
399
15d46f38
BS		 400 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
401 info->status.ampdu_ack_len =
402 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
ec8aa669
FF		 403 info->status.ampdu_len = 1;
404 }
405
406 mi->ampdu_packets++;
407 mi->ampdu_len += info->status.ampdu_len;
408
409 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
410 mi->sample_wait = 4 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
411 mi->sample_tries = 3;
412 mi->sample_count--;
413 }
414
415 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) {
416 mi->sample_packets += info->status.ampdu_len;
417 minstrel_next_sample_idx(mi);
418 }
419
420 for (i = 0; !last; i++) {
421 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
422 !minstrel_ht_txstat_valid(&ar[i + 1]);
423
424 if (!minstrel_ht_txstat_valid(&ar[i]))
425 break;
426
427 group = minstrel_ht_get_group_idx(&ar[i]);
428 rate = &mi->groups[group].rates[ar[i].idx % 8];
429
15d46f38 430 if (last)
ec8aa669
FF		 431 rate->success += info->status.ampdu_ack_len;
432
433 rate->attempts += ar[i].count * info->status.ampdu_len;
434 }
435
436 /*
437 * check for sudden death of spatial multiplexing,
438 * downgrade to a lower number of streams if necessary.
439 */
440 rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
441 if (rate->attempts > 30 &&
442 MINSTREL_FRAC(rate->success, rate->attempts) <
443 MINSTREL_FRAC(20, 100))
444 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
445
446 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
ecc3d5ae
ML		 447 if (rate2->attempts > 30 &&
448 MINSTREL_FRAC(rate2->success, rate2->attempts) <
ec8aa669
FF		 449 MINSTREL_FRAC(20, 100))
450 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
451
452 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
453 minstrel_ht_update_stats(mp, mi);
454 minstrel_aggr_check(mp, sta, skb);
455 }
456}
457
458static void
459minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
460 int index)
461{
462 struct minstrel_rate_stats *mr;
463 const struct mcs_group *group;
464 unsigned int tx_time, tx_time_rtscts, tx_time_data;
465 unsigned int cw = mp->cw_min;
466 unsigned int t_slot = 9; /* FIXME */
467 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
468
469 mr = minstrel_get_ratestats(mi, index);
470 if (mr->probability < MINSTREL_FRAC(1, 10)) {
471 mr->retry_count = 1;
472 mr->retry_count_rtscts = 1;
473 return;
474 }
475
476 mr->retry_count = 2;
477 mr->retry_count_rtscts = 2;
478 mr->retry_updated = true;
479
480 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
481 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len;
482 tx_time = 2 * (t_slot + mi->overhead + tx_time_data);
483 tx_time_rtscts = 2 * (t_slot + mi->overhead_rtscts + tx_time_data);
484 do {
485 cw = (cw << 1) | 1;
486 cw = min(cw, mp->cw_max);
487 tx_time += cw + t_slot + mi->overhead;
488 tx_time_rtscts += cw + t_slot + mi->overhead_rtscts;
489 if (tx_time_rtscts < mp->segment_size)
490 mr->retry_count_rtscts++;
491 } while ((tx_time < mp->segment_size) &&
492 (++mr->retry_count < mp->max_retry));
493}
494
495
496static void
497minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
498 struct ieee80211_tx_rate *rate, int index,
499 struct ieee80211_tx_rate_control *txrc,
500 bool sample, bool rtscts)
501{
502 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
503 struct minstrel_rate_stats *mr;
504
505 mr = minstrel_get_ratestats(mi, index);
506 if (!mr->retry_updated)
507 minstrel_calc_retransmit(mp, mi, index);
508
509 if (mr->probability < MINSTREL_FRAC(20, 100))
510 rate->count = 2;
511 else if (rtscts)
512 rate->count = mr->retry_count_rtscts;
513 else
514 rate->count = mr->retry_count;
515
516 rate->flags = IEEE80211_TX_RC_MCS | group->flags;
517 if (txrc->short_preamble)
518 rate->flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
519 if (txrc->rts || rtscts)
520 rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS;
521 rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES;
522}
523
524static inline int
525minstrel_get_duration(int index)
526{
527 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
528 return group->duration[index % MCS_GROUP_RATES];
529}
530
531static int
532minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
533{
534 struct minstrel_rate_stats *mr;
535 struct minstrel_mcs_group_data *mg;
536 int sample_idx = 0;
537
538 if (mi->sample_wait > 0) {
539 mi->sample_wait--;
540 return -1;
541 }
542
543 if (!mi->sample_tries)
544 return -1;
545
546 mi->sample_tries--;
547 mg = &mi->groups[mi->sample_group];
548 sample_idx = sample_table[mg->column][mg->index];
549 mr = &mg->rates[sample_idx];
550 sample_idx += mi->sample_group * MCS_GROUP_RATES;
551
552 /*
553 * When not using MRR, do not sample if the probability is already
554 * higher than 95% to avoid wasting airtime
555 */
556 if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100)))
557 goto next;
558
559 /*
560 * Make sure that lower rates get sampled only occasionally,
561 * if the link is working perfectly.
562 */
563 if (minstrel_get_duration(sample_idx) >
564 minstrel_get_duration(mi->max_tp_rate)) {
565 if (mr->sample_skipped < 10)
566 goto next;
567
568 if (mi->sample_slow++ > 2)
569 goto next;
570 }
571
572 return sample_idx;
573
574next:
575 minstrel_next_sample_idx(mi);
576 return -1;
577}
578
579static void
580minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
581 struct ieee80211_tx_rate_control *txrc)
582{
583 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
584 struct ieee80211_tx_rate *ar = info->status.rates;
585 struct minstrel_ht_sta_priv *msp = priv_sta;
586 struct minstrel_ht_sta *mi = &msp->ht;
587 struct minstrel_priv *mp = priv;
588 int sample_idx;
589
590 if (rate_control_send_low(sta, priv_sta, txrc))
591 return;
592
593 if (!msp->is_ht)
594 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
595
596 info->flags |= mi->tx_flags;
597 sample_idx = minstrel_get_sample_rate(mp, mi);
598 if (sample_idx >= 0) {
599 minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
600 txrc, true, false);
601 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
602 txrc, false, true);
603 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
604 } else {
605 minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
606 txrc, false, false);
607 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2,
608 txrc, false, true);
609 }
610 minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, txrc, false, true);
611
612 ar[3].count = 0;
613 ar[3].idx = -1;
614
615 mi->total_packets++;
616
617 /* wraparound */
618 if (mi->total_packets == ~0) {
619 mi->total_packets = 0;
620 mi->sample_packets = 0;
621 }
622}
623
624static void
625minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
626 struct ieee80211_sta *sta, void *priv_sta,
627 enum nl80211_channel_type oper_chan_type)
628{
629 struct minstrel_priv *mp = priv;
630 struct minstrel_ht_sta_priv *msp = priv_sta;
631 struct minstrel_ht_sta *mi = &msp->ht;
632 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
633 struct ieee80211_local *local = hw_to_local(mp->hw);
634 u16 sta_cap = sta->ht_cap.cap;
635 int ack_dur;
636 int stbc;
637 int i;
638
639 /* fall back to the old minstrel for legacy stations */
00fc90c8 640 if (!sta->ht_cap.ht_supported) {
ec8aa669
FF		 641 msp->is_ht = false;
642 memset(&msp->legacy, 0, sizeof(msp->legacy));
643 msp->legacy.r = msp->ratelist;
644 msp->legacy.sample_table = msp->sample_table;
645 return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy);
646 }
647
648 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
649 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS);
650
651 msp->is_ht = true;
652 memset(mi, 0, sizeof(*mi));
653 mi->stats_update = jiffies;
654
655 ack_dur = ieee80211_frame_duration(local, 10, 60, 1, 1);
656 mi->overhead = ieee80211_frame_duration(local, 0, 60, 1, 1) + ack_dur;
657 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
658
659 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
660
661 /* When using MRR, sample more on the first attempt, without delay */
662 if (mp->has_mrr) {
663 mi->sample_count = 16;
664 mi->sample_wait = 0;
665 } else {
666 mi->sample_count = 8;
667 mi->sample_wait = 8;
668 }
669 mi->sample_tries = 4;
670
671 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
672 IEEE80211_HT_CAP_RX_STBC_SHIFT;
673 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
674
675 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
676 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
677
678 if (oper_chan_type != NL80211_CHAN_HT40MINUS &&
679 oper_chan_type != NL80211_CHAN_HT40PLUS)
680 sta_cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
681
682 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
683 u16 req = 0;
684
685 mi->groups[i].supported = 0;
686 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
687 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
688 req |= IEEE80211_HT_CAP_SGI_40;
689 else
690 req |= IEEE80211_HT_CAP_SGI_20;
691 }
692
693 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
694 req |= IEEE80211_HT_CAP_SUP_WIDTH_20_40;
695
696 if ((sta_cap & req) != req)
697 continue;
698
699 mi->groups[i].supported =
700 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
701 }
702}
703
704static void
705minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
706 struct ieee80211_sta *sta, void *priv_sta)
707{
708 struct minstrel_priv *mp = priv;
709
710 minstrel_ht_update_caps(priv, sband, sta, priv_sta, mp->hw->conf.channel_type);
711}
712
713static void
714minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
715 struct ieee80211_sta *sta, void *priv_sta,
716 u32 changed, enum nl80211_channel_type oper_chan_type)
717{
718 minstrel_ht_update_caps(priv, sband, sta, priv_sta, oper_chan_type);
719}
720
721static void *
722minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
723{
724 struct ieee80211_supported_band *sband;
725 struct minstrel_ht_sta_priv *msp;
726 struct minstrel_priv *mp = priv;
727 struct ieee80211_hw *hw = mp->hw;
728 int max_rates = 0;
729 int i;
730
731 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
732 sband = hw->wiphy->bands[i];
733 if (sband && sband->n_bitrates > max_rates)
734 max_rates = sband->n_bitrates;
735 }
736
737 msp = kzalloc(sizeof(struct minstrel_ht_sta), gfp);
738 if (!msp)
739 return NULL;
740
741 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
742 if (!msp->ratelist)
743 goto error;
744
745 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
746 if (!msp->sample_table)
747 goto error1;
748
749 return msp;
750
751error1:
7e988014 752 kfree(msp->ratelist);
ec8aa669
FF		 753error:
754 kfree(msp);
755 return NULL;
756}
757
758static void
759minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
760{
761 struct minstrel_ht_sta_priv *msp = priv_sta;
762
763 kfree(msp->sample_table);
764 kfree(msp->ratelist);
765 kfree(msp);
766}
767
768static void *
769minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
770{
771 return mac80211_minstrel.alloc(hw, debugfsdir);
772}
773
774static void
775minstrel_ht_free(void *priv)
776{
777 mac80211_minstrel.free(priv);
778}
779
780static struct rate_control_ops mac80211_minstrel_ht = {
781 .name = "minstrel_ht",
782 .tx_status = minstrel_ht_tx_status,
783 .get_rate = minstrel_ht_get_rate,
784 .rate_init = minstrel_ht_rate_init,
785 .rate_update = minstrel_ht_rate_update,
786 .alloc_sta = minstrel_ht_alloc_sta,
787 .free_sta = minstrel_ht_free_sta,
788 .alloc = minstrel_ht_alloc,
789 .free = minstrel_ht_free,
790#ifdef CONFIG_MAC80211_DEBUGFS
791 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
792 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
793#endif
794};
795
796
797static void
798init_sample_table(void)
799{
800 int col, i, new_idx;
801 u8 rnd[MCS_GROUP_RATES];
802
803 memset(sample_table, 0xff, sizeof(sample_table));
804 for (col = 0; col < SAMPLE_COLUMNS; col++) {
805 for (i = 0; i < MCS_GROUP_RATES; i++) {
806 get_random_bytes(rnd, sizeof(rnd));
807 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
808
809 while (sample_table[col][new_idx] != 0xff)
810 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
811
812 sample_table[col][new_idx] = i;
813 }
814 }
815}
816
817int __init
818rc80211_minstrel_ht_init(void)
819{
820 init_sample_table();
821 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
822}
823
824void
825rc80211_minstrel_ht_exit(void)
826{
827 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
828}
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