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[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) {
c7317e41
FF		 410 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
411 mi->sample_tries = 2;
ec8aa669
FF		 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
c7317e41
FF		 509 if (sample)
510 rate->count = 1;
511 else if (mr->probability < MINSTREL_FRAC(20, 100))
ec8aa669
FF		 512 rate->count = 2;
513 else if (rtscts)
514 rate->count = mr->retry_count_rtscts;
515 else
516 rate->count = mr->retry_count;
517
518 rate->flags = IEEE80211_TX_RC_MCS | group->flags;
519 if (txrc->short_preamble)
520 rate->flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
521 if (txrc->rts || rtscts)
522 rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS;
523 rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES;
524}
525
526static inline int
527minstrel_get_duration(int index)
528{
529 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
530 return group->duration[index % MCS_GROUP_RATES];
531}
532
533static int
534minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
535{
536 struct minstrel_rate_stats *mr;
537 struct minstrel_mcs_group_data *mg;
538 int sample_idx = 0;
539
540 if (mi->sample_wait > 0) {
541 mi->sample_wait--;
542 return -1;
543 }
544
545 if (!mi->sample_tries)
546 return -1;
547
548 mi->sample_tries--;
549 mg = &mi->groups[mi->sample_group];
550 sample_idx = sample_table[mg->column][mg->index];
551 mr = &mg->rates[sample_idx];
552 sample_idx += mi->sample_group * MCS_GROUP_RATES;
553
554 /*
555 * When not using MRR, do not sample if the probability is already
556 * higher than 95% to avoid wasting airtime
557 */
558 if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100)))
559 goto next;
560
561 /*
562 * Make sure that lower rates get sampled only occasionally,
563 * if the link is working perfectly.
564 */
565 if (minstrel_get_duration(sample_idx) >
566 minstrel_get_duration(mi->max_tp_rate)) {
c7317e41 567 if (mr->sample_skipped < 20)
ec8aa669
FF		 568 goto next;
569
570 if (mi->sample_slow++ > 2)
571 goto next;
572 }
573
574 return sample_idx;
575
576next:
577 minstrel_next_sample_idx(mi);
578 return -1;
579}
580
581static void
582minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
583 struct ieee80211_tx_rate_control *txrc)
584{
585 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
586 struct ieee80211_tx_rate *ar = info->status.rates;
587 struct minstrel_ht_sta_priv *msp = priv_sta;
588 struct minstrel_ht_sta *mi = &msp->ht;
589 struct minstrel_priv *mp = priv;
590 int sample_idx;
c7317e41 591 bool sample = false;
ec8aa669
FF		 592
593 if (rate_control_send_low(sta, priv_sta, txrc))
594 return;
595
596 if (!msp->is_ht)
597 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
598
599 info->flags |= mi->tx_flags;
600 sample_idx = minstrel_get_sample_rate(mp, mi);
601 if (sample_idx >= 0) {
c7317e41 602 sample = true;
ec8aa669
FF		 603 minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
604 txrc, true, false);
605 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
c7317e41 606 txrc, false, false);
ec8aa669
FF		 607 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
608 } else {
609 minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
610 txrc, false, false);
611 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2,
612 txrc, false, true);
613 }
c7317e41 614 minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, txrc, false, !sample);
ec8aa669
FF		 615
616 ar[3].count = 0;
617 ar[3].idx = -1;
618
619 mi->total_packets++;
620
621 /* wraparound */
622 if (mi->total_packets == ~0) {
623 mi->total_packets = 0;
624 mi->sample_packets = 0;
625 }
626}
627
628static void
629minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
630 struct ieee80211_sta *sta, void *priv_sta,
631 enum nl80211_channel_type oper_chan_type)
632{
633 struct minstrel_priv *mp = priv;
634 struct minstrel_ht_sta_priv *msp = priv_sta;
635 struct minstrel_ht_sta *mi = &msp->ht;
636 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
637 struct ieee80211_local *local = hw_to_local(mp->hw);
638 u16 sta_cap = sta->ht_cap.cap;
639 int ack_dur;
640 int stbc;
641 int i;
642
643 /* fall back to the old minstrel for legacy stations */
00fc90c8 644 if (!sta->ht_cap.ht_supported) {
ec8aa669
FF		 645 msp->is_ht = false;
646 memset(&msp->legacy, 0, sizeof(msp->legacy));
647 msp->legacy.r = msp->ratelist;
648 msp->legacy.sample_table = msp->sample_table;
649 return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy);
650 }
651
652 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
653 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS);
654
655 msp->is_ht = true;
656 memset(mi, 0, sizeof(*mi));
657 mi->stats_update = jiffies;
658
659 ack_dur = ieee80211_frame_duration(local, 10, 60, 1, 1);
660 mi->overhead = ieee80211_frame_duration(local, 0, 60, 1, 1) + ack_dur;
661 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
662
663 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
664
665 /* When using MRR, sample more on the first attempt, without delay */
666 if (mp->has_mrr) {
667 mi->sample_count = 16;
668 mi->sample_wait = 0;
669 } else {
670 mi->sample_count = 8;
671 mi->sample_wait = 8;
672 }
673 mi->sample_tries = 4;
674
675 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
676 IEEE80211_HT_CAP_RX_STBC_SHIFT;
677 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
678
679 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
680 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
681
682 if (oper_chan_type != NL80211_CHAN_HT40MINUS &&
683 oper_chan_type != NL80211_CHAN_HT40PLUS)
684 sta_cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
685
686 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
687 u16 req = 0;
688
689 mi->groups[i].supported = 0;
690 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
691 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
692 req |= IEEE80211_HT_CAP_SGI_40;
693 else
694 req |= IEEE80211_HT_CAP_SGI_20;
695 }
696
697 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
698 req |= IEEE80211_HT_CAP_SUP_WIDTH_20_40;
699
700 if ((sta_cap & req) != req)
701 continue;
702
703 mi->groups[i].supported =
704 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
705 }
706}
707
708static void
709minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
710 struct ieee80211_sta *sta, void *priv_sta)
711{
712 struct minstrel_priv *mp = priv;
713
714 minstrel_ht_update_caps(priv, sband, sta, priv_sta, mp->hw->conf.channel_type);
715}
716
717static void
718minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
719 struct ieee80211_sta *sta, void *priv_sta,
720 u32 changed, enum nl80211_channel_type oper_chan_type)
721{
722 minstrel_ht_update_caps(priv, sband, sta, priv_sta, oper_chan_type);
723}
724
725static void *
726minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
727{
728 struct ieee80211_supported_band *sband;
729 struct minstrel_ht_sta_priv *msp;
730 struct minstrel_priv *mp = priv;
731 struct ieee80211_hw *hw = mp->hw;
732 int max_rates = 0;
733 int i;
734
735 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
736 sband = hw->wiphy->bands[i];
737 if (sband && sband->n_bitrates > max_rates)
738 max_rates = sband->n_bitrates;
739 }
740
741 msp = kzalloc(sizeof(struct minstrel_ht_sta), gfp);
742 if (!msp)
743 return NULL;
744
745 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
746 if (!msp->ratelist)
747 goto error;
748
749 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
750 if (!msp->sample_table)
751 goto error1;
752
753 return msp;
754
755error1:
7e988014 756 kfree(msp->ratelist);
ec8aa669
FF		 757error:
758 kfree(msp);
759 return NULL;
760}
761
762static void
763minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
764{
765 struct minstrel_ht_sta_priv *msp = priv_sta;
766
767 kfree(msp->sample_table);
768 kfree(msp->ratelist);
769 kfree(msp);
770}
771
772static void *
773minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
774{
775 return mac80211_minstrel.alloc(hw, debugfsdir);
776}
777
778static void
779minstrel_ht_free(void *priv)
780{
781 mac80211_minstrel.free(priv);
782}
783
784static struct rate_control_ops mac80211_minstrel_ht = {
785 .name = "minstrel_ht",
786 .tx_status = minstrel_ht_tx_status,
787 .get_rate = minstrel_ht_get_rate,
788 .rate_init = minstrel_ht_rate_init,
789 .rate_update = minstrel_ht_rate_update,
790 .alloc_sta = minstrel_ht_alloc_sta,
791 .free_sta = minstrel_ht_free_sta,
792 .alloc = minstrel_ht_alloc,
793 .free = minstrel_ht_free,
794#ifdef CONFIG_MAC80211_DEBUGFS
795 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
796 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
797#endif
798};
799
800
801static void
802init_sample_table(void)
803{
804 int col, i, new_idx;
805 u8 rnd[MCS_GROUP_RATES];
806
807 memset(sample_table, 0xff, sizeof(sample_table));
808 for (col = 0; col < SAMPLE_COLUMNS; col++) {
809 for (i = 0; i < MCS_GROUP_RATES; i++) {
810 get_random_bytes(rnd, sizeof(rnd));
811 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
812
813 while (sample_table[col][new_idx] != 0xff)
814 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
815
816 sample_table[col][new_idx] = i;
817 }
818 }
819}
820
821int __init
822rc80211_minstrel_ht_init(void)
823{
824 init_sample_table();
825 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
826}
827
828void
829rc80211_minstrel_ht_exit(void)
830{
831 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
832}
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