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Merge tag 'v3.16-rc4' into drm-intel-next-queued
[deliverable/linux.git] / net / mac80211 / rc80211_minstrel_ht.c
1 /*
2 * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8 #include <linux/netdevice.h>
9 #include <linux/types.h>
10 #include <linux/skbuff.h>
11 #include <linux/debugfs.h>
12 #include <linux/random.h>
13 #include <linux/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
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) DIV_ROUND_UP(MCS_NBITS, (bps))
26
27 /* Transmission time (nanoseconds) for a packet containing (syms) symbols */
28 #define MCS_SYMBOL_TIME(sgi, syms) \
29 (sgi ? \
30 ((syms) * 18000 + 4000) / 5 : /* syms * 3.6 us */ \
31 ((syms) * 1000) << 2 /* syms * 4 us */ \
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
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
45 /* MCS rate information for an MCS group */
46 #define MCS_GROUP(_streams, _sgi, _ht40) \
47 [GROUP_IDX(_streams, _sgi, _ht40)] = { \
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
64 #define CCK_DURATION(_bitrate, _short, _len) \
65 (1000 * (10 /* SIFS */ + \
66 (_short ? 72 + 24 : 144 + 48) + \
67 (8 * (_len + 4) * 10) / (_bitrate)))
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
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.
92 *
93 * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
94 * HT40 -> SGI -> #streams
95 */
96 const 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
120
121 /* must be last */
122 CCK_GROUP
123 };
124
125 #define MINSTREL_CCK_GROUP (ARRAY_SIZE(minstrel_mcs_groups) - 1)
126
127 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
128
129 static void
130 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
131
132 /*
133 * Look up an MCS group index based on mac80211 rate information
134 */
135 static int
136 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
137 {
138 return GROUP_IDX((rate->idx / 8) + 1,
139 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
140 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
141 }
142
143 static struct minstrel_rate_stats *
144 minstrel_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);
151 idx = rate->idx % 8;
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
166 static inline struct minstrel_rate_stats *
167 minstrel_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 */
176 static void
177 minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr)
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 */
202 static void
203 minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
204 {
205 struct minstrel_rate_stats *mr;
206 unsigned int nsecs = 0;
207 unsigned int tp;
208 unsigned int prob;
209
210 mr = &mi->groups[group].rates[rate];
211 prob = mr->probability;
212
213 if (prob < MINSTREL_FRAC(1, 10)) {
214 mr->cur_tp = 0;
215 return;
216 }
217
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
225 if (group != MINSTREL_CCK_GROUP)
226 nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
227
228 nsecs += minstrel_mcs_groups[group].duration[rate];
229
230 /* prob is scaled - see MINSTREL_FRAC above */
231 tp = 1000000 * ((prob * 1000) / nsecs);
232 mr->cur_tp = MINSTREL_TRUNC(tp);
233 }
234
235 /*
236 * Update rate statistics and select new primary rates
237 *
238 * Rules for rate selection:
239 * - max_prob_rate must use only one stream, as a tradeoff between delivery
240 * probability and throughput during strong fluctuations
241 * - as long as the max prob rate has a probability of more than 3/4, pick
242 * higher throughput rates, even if the probablity is a bit lower
243 */
244 static void
245 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
246 {
247 struct minstrel_mcs_group_data *mg;
248 struct minstrel_rate_stats *mr;
249 int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
250 int group, i, index;
251 bool mi_rates_valid = false;
252
253 if (mi->ampdu_packets > 0) {
254 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
255 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
256 mi->ampdu_len = 0;
257 mi->ampdu_packets = 0;
258 }
259
260 mi->sample_slow = 0;
261 mi->sample_count = 0;
262
263 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
264 bool mg_rates_valid = false;
265
266 cur_prob = 0;
267 cur_prob_tp = 0;
268 cur_tp = 0;
269 cur_tp2 = 0;
270
271 mg = &mi->groups[group];
272 if (!mg->supported)
273 continue;
274
275 mi->sample_count++;
276
277 for (i = 0; i < MCS_GROUP_RATES; i++) {
278 if (!(mg->supported & BIT(i)))
279 continue;
280
281 index = MCS_GROUP_RATES * group + i;
282
283 /* initialize rates selections starting indexes */
284 if (!mg_rates_valid) {
285 mg->max_tp_rate = mg->max_tp_rate2 =
286 mg->max_prob_rate = i;
287 if (!mi_rates_valid) {
288 mi->max_tp_rate = mi->max_tp_rate2 =
289 mi->max_prob_rate = index;
290 mi_rates_valid = true;
291 }
292 mg_rates_valid = true;
293 }
294
295 mr = &mg->rates[i];
296 mr->retry_updated = false;
297 minstrel_calc_rate_ewma(mr);
298 minstrel_ht_calc_tp(mi, group, i);
299
300 if (!mr->cur_tp)
301 continue;
302
303 if ((mr->cur_tp > cur_prob_tp && mr->probability >
304 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
305 mg->max_prob_rate = index;
306 cur_prob = mr->probability;
307 cur_prob_tp = mr->cur_tp;
308 }
309
310 if (mr->cur_tp > cur_tp) {
311 swap(index, mg->max_tp_rate);
312 cur_tp = mr->cur_tp;
313 mr = minstrel_get_ratestats(mi, index);
314 }
315
316 if (index >= mg->max_tp_rate)
317 continue;
318
319 if (mr->cur_tp > cur_tp2) {
320 mg->max_tp_rate2 = index;
321 cur_tp2 = mr->cur_tp;
322 }
323 }
324 }
325
326 /* try to sample all available rates during each interval */
327 mi->sample_count *= 8;
328
329 cur_prob = 0;
330 cur_prob_tp = 0;
331 cur_tp = 0;
332 cur_tp2 = 0;
333 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
334 mg = &mi->groups[group];
335 if (!mg->supported)
336 continue;
337
338 mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
339 if (cur_tp < mr->cur_tp) {
340 mi->max_tp_rate2 = mi->max_tp_rate;
341 cur_tp2 = cur_tp;
342 mi->max_tp_rate = mg->max_tp_rate;
343 cur_tp = mr->cur_tp;
344 mi->max_prob_streams = minstrel_mcs_groups[group].streams - 1;
345 }
346
347 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
348 if (cur_tp2 < mr->cur_tp) {
349 mi->max_tp_rate2 = mg->max_tp_rate2;
350 cur_tp2 = mr->cur_tp;
351 }
352 }
353
354 if (mi->max_prob_streams < 1)
355 mi->max_prob_streams = 1;
356
357 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
358 mg = &mi->groups[group];
359 if (!mg->supported)
360 continue;
361 mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
362 if (cur_prob_tp < mr->cur_tp &&
363 minstrel_mcs_groups[group].streams <= mi->max_prob_streams) {
364 mi->max_prob_rate = mg->max_prob_rate;
365 cur_prob = mr->cur_prob;
366 cur_prob_tp = mr->cur_tp;
367 }
368 }
369
370 #ifdef CONFIG_MAC80211_DEBUGFS
371 /* use fixed index if set */
372 if (mp->fixed_rate_idx != -1) {
373 mi->max_tp_rate = mp->fixed_rate_idx;
374 mi->max_tp_rate2 = mp->fixed_rate_idx;
375 mi->max_prob_rate = mp->fixed_rate_idx;
376 }
377 #endif
378
379 mi->stats_update = jiffies;
380 }
381
382 static bool
383 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
384 {
385 if (rate->idx < 0)
386 return false;
387
388 if (!rate->count)
389 return false;
390
391 if (rate->flags & IEEE80211_TX_RC_MCS)
392 return true;
393
394 return rate->idx == mp->cck_rates[0] ||
395 rate->idx == mp->cck_rates[1] ||
396 rate->idx == mp->cck_rates[2] ||
397 rate->idx == mp->cck_rates[3];
398 }
399
400 static void
401 minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
402 {
403 struct minstrel_mcs_group_data *mg;
404
405 for (;;) {
406 mi->sample_group++;
407 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
408 mg = &mi->groups[mi->sample_group];
409
410 if (!mg->supported)
411 continue;
412
413 if (++mg->index >= MCS_GROUP_RATES) {
414 mg->index = 0;
415 if (++mg->column >= ARRAY_SIZE(sample_table))
416 mg->column = 0;
417 }
418 break;
419 }
420 }
421
422 static void
423 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx,
424 bool primary)
425 {
426 int group, orig_group;
427
428 orig_group = group = *idx / MCS_GROUP_RATES;
429 while (group > 0) {
430 group--;
431
432 if (!mi->groups[group].supported)
433 continue;
434
435 if (minstrel_mcs_groups[group].streams >
436 minstrel_mcs_groups[orig_group].streams)
437 continue;
438
439 if (primary)
440 *idx = mi->groups[group].max_tp_rate;
441 else
442 *idx = mi->groups[group].max_tp_rate2;
443 break;
444 }
445 }
446
447 static void
448 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
449 {
450 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
451 struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
452 u16 tid;
453
454 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
455 return;
456
457 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
458 return;
459
460 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
461 if (likely(sta->ampdu_mlme.tid_tx[tid]))
462 return;
463
464 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
465 return;
466
467 ieee80211_start_tx_ba_session(pubsta, tid, 5000);
468 }
469
470 static void
471 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
472 struct ieee80211_sta *sta, void *priv_sta,
473 struct sk_buff *skb)
474 {
475 struct minstrel_ht_sta_priv *msp = priv_sta;
476 struct minstrel_ht_sta *mi = &msp->ht;
477 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
478 struct ieee80211_tx_rate *ar = info->status.rates;
479 struct minstrel_rate_stats *rate, *rate2;
480 struct minstrel_priv *mp = priv;
481 bool last, update = false;
482 int i;
483
484 if (!msp->is_ht)
485 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
486
487 /* This packet was aggregated but doesn't carry status info */
488 if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
489 !(info->flags & IEEE80211_TX_STAT_AMPDU))
490 return;
491
492 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
493 info->status.ampdu_ack_len =
494 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
495 info->status.ampdu_len = 1;
496 }
497
498 mi->ampdu_packets++;
499 mi->ampdu_len += info->status.ampdu_len;
500
501 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
502 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
503 mi->sample_tries = 1;
504 mi->sample_count--;
505 }
506
507 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
508 mi->sample_packets += info->status.ampdu_len;
509
510 last = !minstrel_ht_txstat_valid(mp, &ar[0]);
511 for (i = 0; !last; i++) {
512 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
513 !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
514
515 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
516
517 if (last)
518 rate->success += info->status.ampdu_ack_len;
519
520 rate->attempts += ar[i].count * info->status.ampdu_len;
521 }
522
523 /*
524 * check for sudden death of spatial multiplexing,
525 * downgrade to a lower number of streams if necessary.
526 */
527 rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
528 if (rate->attempts > 30 &&
529 MINSTREL_FRAC(rate->success, rate->attempts) <
530 MINSTREL_FRAC(20, 100)) {
531 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
532 update = true;
533 }
534
535 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
536 if (rate2->attempts > 30 &&
537 MINSTREL_FRAC(rate2->success, rate2->attempts) <
538 MINSTREL_FRAC(20, 100)) {
539 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
540 update = true;
541 }
542
543 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
544 update = true;
545 minstrel_ht_update_stats(mp, mi);
546 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
547 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
548 minstrel_aggr_check(sta, skb);
549 }
550
551 if (update)
552 minstrel_ht_update_rates(mp, mi);
553 }
554
555 static void
556 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
557 int index)
558 {
559 struct minstrel_rate_stats *mr;
560 const struct mcs_group *group;
561 unsigned int tx_time, tx_time_rtscts, tx_time_data;
562 unsigned int cw = mp->cw_min;
563 unsigned int ctime = 0;
564 unsigned int t_slot = 9; /* FIXME */
565 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
566 unsigned int overhead = 0, overhead_rtscts = 0;
567
568 mr = minstrel_get_ratestats(mi, index);
569 if (mr->probability < MINSTREL_FRAC(1, 10)) {
570 mr->retry_count = 1;
571 mr->retry_count_rtscts = 1;
572 return;
573 }
574
575 mr->retry_count = 2;
576 mr->retry_count_rtscts = 2;
577 mr->retry_updated = true;
578
579 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
580 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
581
582 /* Contention time for first 2 tries */
583 ctime = (t_slot * cw) >> 1;
584 cw = min((cw << 1) | 1, mp->cw_max);
585 ctime += (t_slot * cw) >> 1;
586 cw = min((cw << 1) | 1, mp->cw_max);
587
588 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
589 overhead = mi->overhead;
590 overhead_rtscts = mi->overhead_rtscts;
591 }
592
593 /* Total TX time for data and Contention after first 2 tries */
594 tx_time = ctime + 2 * (overhead + tx_time_data);
595 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
596
597 /* See how many more tries we can fit inside segment size */
598 do {
599 /* Contention time for this try */
600 ctime = (t_slot * cw) >> 1;
601 cw = min((cw << 1) | 1, mp->cw_max);
602
603 /* Total TX time after this try */
604 tx_time += ctime + overhead + tx_time_data;
605 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
606
607 if (tx_time_rtscts < mp->segment_size)
608 mr->retry_count_rtscts++;
609 } while ((tx_time < mp->segment_size) &&
610 (++mr->retry_count < mp->max_retry));
611 }
612
613
614 static void
615 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
616 struct ieee80211_sta_rates *ratetbl, int offset, int index)
617 {
618 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
619 struct minstrel_rate_stats *mr;
620 u8 idx;
621 u16 flags;
622
623 mr = minstrel_get_ratestats(mi, index);
624 if (!mr->retry_updated)
625 minstrel_calc_retransmit(mp, mi, index);
626
627 if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) {
628 ratetbl->rate[offset].count = 2;
629 ratetbl->rate[offset].count_rts = 2;
630 ratetbl->rate[offset].count_cts = 2;
631 } else {
632 ratetbl->rate[offset].count = mr->retry_count;
633 ratetbl->rate[offset].count_cts = mr->retry_count;
634 ratetbl->rate[offset].count_rts = mr->retry_count_rtscts;
635 }
636
637 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
638 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
639 flags = 0;
640 } else {
641 idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;
642 flags = IEEE80211_TX_RC_MCS | group->flags;
643 }
644
645 if (offset > 0) {
646 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
647 flags |= IEEE80211_TX_RC_USE_RTS_CTS;
648 }
649
650 ratetbl->rate[offset].idx = idx;
651 ratetbl->rate[offset].flags = flags;
652 }
653
654 static void
655 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
656 {
657 struct ieee80211_sta_rates *rates;
658 int i = 0;
659
660 rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
661 if (!rates)
662 return;
663
664 /* Start with max_tp_rate */
665 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate);
666
667 if (mp->hw->max_rates >= 3) {
668 /* At least 3 tx rates supported, use max_tp_rate2 next */
669 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate2);
670 }
671
672 if (mp->hw->max_rates >= 2) {
673 /*
674 * At least 2 tx rates supported, use max_prob_rate next */
675 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
676 }
677
678 rates->rate[i].idx = -1;
679 rate_control_set_rates(mp->hw, mi->sta, rates);
680 }
681
682 static inline int
683 minstrel_get_duration(int index)
684 {
685 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
686 return group->duration[index % MCS_GROUP_RATES];
687 }
688
689 static int
690 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
691 {
692 struct minstrel_rate_stats *mr;
693 struct minstrel_mcs_group_data *mg;
694 unsigned int sample_dur, sample_group;
695 int sample_idx = 0;
696
697 if (mi->sample_wait > 0) {
698 mi->sample_wait--;
699 return -1;
700 }
701
702 if (!mi->sample_tries)
703 return -1;
704
705 sample_group = mi->sample_group;
706 mg = &mi->groups[sample_group];
707 sample_idx = sample_table[mg->column][mg->index];
708 minstrel_next_sample_idx(mi);
709
710 if (!(mg->supported & BIT(sample_idx)))
711 return -1;
712
713 mr = &mg->rates[sample_idx];
714 sample_idx += sample_group * MCS_GROUP_RATES;
715
716 /*
717 * Sampling might add some overhead (RTS, no aggregation)
718 * to the frame. Hence, don't use sampling for the currently
719 * used rates.
720 */
721 if (sample_idx == mi->max_tp_rate ||
722 sample_idx == mi->max_tp_rate2 ||
723 sample_idx == mi->max_prob_rate)
724 return -1;
725
726 /*
727 * Do not sample if the probability is already higher than 95%
728 * to avoid wasting airtime.
729 */
730 if (mr->probability > MINSTREL_FRAC(95, 100))
731 return -1;
732
733 /*
734 * Make sure that lower rates get sampled only occasionally,
735 * if the link is working perfectly.
736 */
737 sample_dur = minstrel_get_duration(sample_idx);
738 if (sample_dur >= minstrel_get_duration(mi->max_tp_rate2) &&
739 (mi->max_prob_streams <
740 minstrel_mcs_groups[sample_group].streams ||
741 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
742 if (mr->sample_skipped < 20)
743 return -1;
744
745 if (mi->sample_slow++ > 2)
746 return -1;
747 }
748 mi->sample_tries--;
749
750 return sample_idx;
751 }
752
753 static void
754 minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp,
755 struct minstrel_ht_sta *mi, bool val)
756 {
757 u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported;
758
759 if (!supported || !mi->cck_supported_short)
760 return;
761
762 if (supported & (mi->cck_supported_short << (val * 4)))
763 return;
764
765 supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4);
766 mi->groups[MINSTREL_CCK_GROUP].supported = supported;
767 }
768
769 static void
770 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
771 struct ieee80211_tx_rate_control *txrc)
772 {
773 const struct mcs_group *sample_group;
774 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
775 struct ieee80211_tx_rate *rate = &info->status.rates[0];
776 struct minstrel_ht_sta_priv *msp = priv_sta;
777 struct minstrel_ht_sta *mi = &msp->ht;
778 struct minstrel_priv *mp = priv;
779 int sample_idx;
780
781 if (rate_control_send_low(sta, priv_sta, txrc))
782 return;
783
784 if (!msp->is_ht)
785 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
786
787 info->flags |= mi->tx_flags;
788 minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble);
789
790 #ifdef CONFIG_MAC80211_DEBUGFS
791 if (mp->fixed_rate_idx != -1)
792 return;
793 #endif
794
795 /* Don't use EAPOL frames for sampling on non-mrr hw */
796 if (mp->hw->max_rates == 1 &&
797 (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
798 sample_idx = -1;
799 else
800 sample_idx = minstrel_get_sample_rate(mp, mi);
801
802 mi->total_packets++;
803
804 /* wraparound */
805 if (mi->total_packets == ~0) {
806 mi->total_packets = 0;
807 mi->sample_packets = 0;
808 }
809
810 if (sample_idx < 0)
811 return;
812
813 sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
814 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
815 rate->count = 1;
816
817 if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
818 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
819 rate->idx = mp->cck_rates[idx];
820 rate->flags = 0;
821 return;
822 }
823
824 rate->idx = sample_idx % MCS_GROUP_RATES +
825 (sample_group->streams - 1) * 8;
826 rate->flags = IEEE80211_TX_RC_MCS | sample_group->flags;
827 }
828
829 static void
830 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
831 struct ieee80211_supported_band *sband,
832 struct ieee80211_sta *sta)
833 {
834 int i;
835
836 if (sband->band != IEEE80211_BAND_2GHZ)
837 return;
838
839 if (!(mp->hw->flags & IEEE80211_HW_SUPPORTS_HT_CCK_RATES))
840 return;
841
842 mi->cck_supported = 0;
843 mi->cck_supported_short = 0;
844 for (i = 0; i < 4; i++) {
845 if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
846 continue;
847
848 mi->cck_supported |= BIT(i);
849 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
850 mi->cck_supported_short |= BIT(i);
851 }
852
853 mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported;
854 }
855
856 static void
857 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
858 struct cfg80211_chan_def *chandef,
859 struct ieee80211_sta *sta, void *priv_sta)
860 {
861 struct minstrel_priv *mp = priv;
862 struct minstrel_ht_sta_priv *msp = priv_sta;
863 struct minstrel_ht_sta *mi = &msp->ht;
864 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
865 u16 sta_cap = sta->ht_cap.cap;
866 int n_supported = 0;
867 int ack_dur;
868 int stbc;
869 int i;
870
871 /* fall back to the old minstrel for legacy stations */
872 if (!sta->ht_cap.ht_supported)
873 goto use_legacy;
874
875 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
876 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1);
877
878 msp->is_ht = true;
879 memset(mi, 0, sizeof(*mi));
880
881 mi->sta = sta;
882 mi->stats_update = jiffies;
883
884 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
885 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
886 mi->overhead += ack_dur;
887 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
888
889 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
890
891 /* When using MRR, sample more on the first attempt, without delay */
892 if (mp->has_mrr) {
893 mi->sample_count = 16;
894 mi->sample_wait = 0;
895 } else {
896 mi->sample_count = 8;
897 mi->sample_wait = 8;
898 }
899 mi->sample_tries = 4;
900
901 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
902 IEEE80211_HT_CAP_RX_STBC_SHIFT;
903 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
904
905 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
906 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
907
908 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
909 mi->groups[i].supported = 0;
910 if (i == MINSTREL_CCK_GROUP) {
911 minstrel_ht_update_cck(mp, mi, sband, sta);
912 continue;
913 }
914
915 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
916 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
917 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
918 continue;
919 } else {
920 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
921 continue;
922 }
923 }
924
925 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
926 sta->bandwidth < IEEE80211_STA_RX_BW_40)
927 continue;
928
929 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
930 if (sta->smps_mode == IEEE80211_SMPS_STATIC &&
931 minstrel_mcs_groups[i].streams > 1)
932 continue;
933
934 mi->groups[i].supported =
935 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
936
937 if (mi->groups[i].supported)
938 n_supported++;
939 }
940
941 if (!n_supported)
942 goto use_legacy;
943
944 /* create an initial rate table with the lowest supported rates */
945 minstrel_ht_update_stats(mp, mi);
946 minstrel_ht_update_rates(mp, mi);
947
948 return;
949
950 use_legacy:
951 msp->is_ht = false;
952 memset(&msp->legacy, 0, sizeof(msp->legacy));
953 msp->legacy.r = msp->ratelist;
954 msp->legacy.sample_table = msp->sample_table;
955 return mac80211_minstrel.rate_init(priv, sband, chandef, sta,
956 &msp->legacy);
957 }
958
959 static void
960 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
961 struct cfg80211_chan_def *chandef,
962 struct ieee80211_sta *sta, void *priv_sta)
963 {
964 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
965 }
966
967 static void
968 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
969 struct cfg80211_chan_def *chandef,
970 struct ieee80211_sta *sta, void *priv_sta,
971 u32 changed)
972 {
973 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
974 }
975
976 static void *
977 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
978 {
979 struct ieee80211_supported_band *sband;
980 struct minstrel_ht_sta_priv *msp;
981 struct minstrel_priv *mp = priv;
982 struct ieee80211_hw *hw = mp->hw;
983 int max_rates = 0;
984 int i;
985
986 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
987 sband = hw->wiphy->bands[i];
988 if (sband && sband->n_bitrates > max_rates)
989 max_rates = sband->n_bitrates;
990 }
991
992 msp = kzalloc(sizeof(*msp), gfp);
993 if (!msp)
994 return NULL;
995
996 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
997 if (!msp->ratelist)
998 goto error;
999
1000 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
1001 if (!msp->sample_table)
1002 goto error1;
1003
1004 return msp;
1005
1006 error1:
1007 kfree(msp->ratelist);
1008 error:
1009 kfree(msp);
1010 return NULL;
1011 }
1012
1013 static void
1014 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1015 {
1016 struct minstrel_ht_sta_priv *msp = priv_sta;
1017
1018 kfree(msp->sample_table);
1019 kfree(msp->ratelist);
1020 kfree(msp);
1021 }
1022
1023 static void *
1024 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
1025 {
1026 return mac80211_minstrel.alloc(hw, debugfsdir);
1027 }
1028
1029 static void
1030 minstrel_ht_free(void *priv)
1031 {
1032 mac80211_minstrel.free(priv);
1033 }
1034
1035 static u32 minstrel_ht_get_expected_throughput(void *priv_sta)
1036 {
1037 struct minstrel_ht_sta_priv *msp = priv_sta;
1038 struct minstrel_ht_sta *mi = &msp->ht;
1039 int i, j;
1040
1041 if (!msp->is_ht)
1042 return mac80211_minstrel.get_expected_throughput(priv_sta);
1043
1044 i = mi->max_tp_rate / MCS_GROUP_RATES;
1045 j = mi->max_tp_rate % MCS_GROUP_RATES;
1046
1047 /* convert cur_tp from pkt per second in kbps */
1048 return mi->groups[i].rates[j].cur_tp * AVG_PKT_SIZE * 8 / 1024;
1049 }
1050
1051 static const struct rate_control_ops mac80211_minstrel_ht = {
1052 .name = "minstrel_ht",
1053 .tx_status = minstrel_ht_tx_status,
1054 .get_rate = minstrel_ht_get_rate,
1055 .rate_init = minstrel_ht_rate_init,
1056 .rate_update = minstrel_ht_rate_update,
1057 .alloc_sta = minstrel_ht_alloc_sta,
1058 .free_sta = minstrel_ht_free_sta,
1059 .alloc = minstrel_ht_alloc,
1060 .free = minstrel_ht_free,
1061 #ifdef CONFIG_MAC80211_DEBUGFS
1062 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
1063 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
1064 #endif
1065 .get_expected_throughput = minstrel_ht_get_expected_throughput,
1066 };
1067
1068
1069 static void __init init_sample_table(void)
1070 {
1071 int col, i, new_idx;
1072 u8 rnd[MCS_GROUP_RATES];
1073
1074 memset(sample_table, 0xff, sizeof(sample_table));
1075 for (col = 0; col < SAMPLE_COLUMNS; col++) {
1076 prandom_bytes(rnd, sizeof(rnd));
1077 for (i = 0; i < MCS_GROUP_RATES; i++) {
1078 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1079 while (sample_table[col][new_idx] != 0xff)
1080 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1081
1082 sample_table[col][new_idx] = i;
1083 }
1084 }
1085 }
1086
1087 int __init
1088 rc80211_minstrel_ht_init(void)
1089 {
1090 init_sample_table();
1091 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1092 }
1093
1094 void
1095 rc80211_minstrel_ht_exit(void)
1096 {
1097 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
1098 }
Linux kernel - Deliverables
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