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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris...
[linux/fpc-iii.git] / net / mac80211 / rc80211_minstrel_ht.c
blobc1b5b73c5b91353597eb1dfcf7a0f70946c72562
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) ((MCS_NBITS + (bps) - 1) / (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];
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 tp = 1000000 * ((prob * 1000) / nsecs);
230
231 mr->cur_tp = MINSTREL_TRUNC(tp);
232 }
233
234 /*
235 * Update rate statistics and select new primary rates
236 *
237 * Rules for rate selection:
238 * - max_prob_rate must use only one stream, as a tradeoff between delivery
239 * probability and throughput during strong fluctuations
240 * - as long as the max prob rate has a probability of more than 3/4, pick
241 * higher throughput rates, even if the probablity is a bit lower
242 */
243 static void
244 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
245 {
246 struct minstrel_mcs_group_data *mg;
247 struct minstrel_rate_stats *mr;
248 int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
249 int group, i, index;
250 bool mi_rates_valid = false;
251
252 if (mi->ampdu_packets > 0) {
253 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
254 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
255 mi->ampdu_len = 0;
256 mi->ampdu_packets = 0;
257 }
258
259 mi->sample_slow = 0;
260 mi->sample_count = 0;
261
262 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
263 bool mg_rates_valid = false;
264
265 cur_prob = 0;
266 cur_prob_tp = 0;
267 cur_tp = 0;
268 cur_tp2 = 0;
269
270 mg = &mi->groups[group];
271 if (!mg->supported)
272 continue;
273
274 mi->sample_count++;
275
276 for (i = 0; i < MCS_GROUP_RATES; i++) {
277 if (!(mg->supported & BIT(i)))
278 continue;
279
280 index = MCS_GROUP_RATES * group + i;
281
282 /* initialize rates selections starting indexes */
283 if (!mg_rates_valid) {
284 mg->max_tp_rate = mg->max_tp_rate2 =
285 mg->max_prob_rate = i;
286 if (!mi_rates_valid) {
287 mi->max_tp_rate = mi->max_tp_rate2 =
288 mi->max_prob_rate = index;
289 mi_rates_valid = true;
290 }
291 mg_rates_valid = true;
292 }
293
294 mr = &mg->rates[i];
295 mr->retry_updated = false;
296 minstrel_calc_rate_ewma(mr);
297 minstrel_ht_calc_tp(mi, group, i);
298
299 if (!mr->cur_tp)
300 continue;
301
302 if ((mr->cur_tp > cur_prob_tp && mr->probability >
303 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
304 mg->max_prob_rate = index;
305 cur_prob = mr->probability;
306 cur_prob_tp = mr->cur_tp;
307 }
308
309 if (mr->cur_tp > cur_tp) {
310 swap(index, mg->max_tp_rate);
311 cur_tp = mr->cur_tp;
312 mr = minstrel_get_ratestats(mi, index);
313 }
314
315 if (index >= mg->max_tp_rate)
316 continue;
317
318 if (mr->cur_tp > cur_tp2) {
319 mg->max_tp_rate2 = index;
320 cur_tp2 = mr->cur_tp;
321 }
322 }
323 }
324
325 /* try to sample all available rates during each interval */
326 mi->sample_count *= 8;
327
328 cur_prob = 0;
329 cur_prob_tp = 0;
330 cur_tp = 0;
331 cur_tp2 = 0;
332 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
333 mg = &mi->groups[group];
334 if (!mg->supported)
335 continue;
336
337 mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
338 if (cur_tp < mr->cur_tp) {
339 mi->max_tp_rate2 = mi->max_tp_rate;
340 cur_tp2 = cur_tp;
341 mi->max_tp_rate = mg->max_tp_rate;
342 cur_tp = mr->cur_tp;
343 mi->max_prob_streams = minstrel_mcs_groups[group].streams - 1;
344 }
345
346 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
347 if (cur_tp2 < mr->cur_tp) {
348 mi->max_tp_rate2 = mg->max_tp_rate2;
349 cur_tp2 = mr->cur_tp;
350 }
351 }
352
353 if (mi->max_prob_streams < 1)
354 mi->max_prob_streams = 1;
355
356 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
357 mg = &mi->groups[group];
358 if (!mg->supported)
359 continue;
360 mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
361 if (cur_prob_tp < mr->cur_tp &&
362 minstrel_mcs_groups[group].streams <= mi->max_prob_streams) {
363 mi->max_prob_rate = mg->max_prob_rate;
364 cur_prob = mr->cur_prob;
365 cur_prob_tp = mr->cur_tp;
366 }
367 }
368
369 #ifdef CONFIG_MAC80211_DEBUGFS
370 /* use fixed index if set */
371 if (mp->fixed_rate_idx != -1) {
372 mi->max_tp_rate = mp->fixed_rate_idx;
373 mi->max_tp_rate2 = mp->fixed_rate_idx;
374 mi->max_prob_rate = mp->fixed_rate_idx;
375 }
376 #endif
377
378 mi->stats_update = jiffies;
379 }
380
381 static bool
382 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
383 {
384 if (rate->idx < 0)
385 return false;
386
387 if (!rate->count)
388 return false;
389
390 if (rate->flags & IEEE80211_TX_RC_MCS)
391 return true;
392
393 return rate->idx == mp->cck_rates[0] ||
394 rate->idx == mp->cck_rates[1] ||
395 rate->idx == mp->cck_rates[2] ||
396 rate->idx == mp->cck_rates[3];
397 }
398
399 static void
400 minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
401 {
402 struct minstrel_mcs_group_data *mg;
403
404 for (;;) {
405 mi->sample_group++;
406 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
407 mg = &mi->groups[mi->sample_group];
408
409 if (!mg->supported)
410 continue;
411
412 if (++mg->index >= MCS_GROUP_RATES) {
413 mg->index = 0;
414 if (++mg->column >= ARRAY_SIZE(sample_table))
415 mg->column = 0;
416 }
417 break;
418 }
419 }
420
421 static void
422 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx,
423 bool primary)
424 {
425 int group, orig_group;
426
427 orig_group = group = *idx / MCS_GROUP_RATES;
428 while (group > 0) {
429 group--;
430
431 if (!mi->groups[group].supported)
432 continue;
433
434 if (minstrel_mcs_groups[group].streams >
435 minstrel_mcs_groups[orig_group].streams)
436 continue;
437
438 if (primary)
439 *idx = mi->groups[group].max_tp_rate;
440 else
441 *idx = mi->groups[group].max_tp_rate2;
442 break;
443 }
444 }
445
446 static void
447 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
448 {
449 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
450 struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
451 u16 tid;
452
453 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
454 return;
455
456 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
457 return;
458
459 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
460 if (likely(sta->ampdu_mlme.tid_tx[tid]))
461 return;
462
463 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
464 return;
465
466 ieee80211_start_tx_ba_session(pubsta, tid, 5000);
467 }
468
469 static void
470 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
471 struct ieee80211_sta *sta, void *priv_sta,
472 struct sk_buff *skb)
473 {
474 struct minstrel_ht_sta_priv *msp = priv_sta;
475 struct minstrel_ht_sta *mi = &msp->ht;
476 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
477 struct ieee80211_tx_rate *ar = info->status.rates;
478 struct minstrel_rate_stats *rate, *rate2;
479 struct minstrel_priv *mp = priv;
480 bool last, update = false;
481 int i;
482
483 if (!msp->is_ht)
484 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
485
486 /* This packet was aggregated but doesn't carry status info */
487 if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
488 !(info->flags & IEEE80211_TX_STAT_AMPDU))
489 return;
490
491 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
492 info->status.ampdu_ack_len =
493 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
494 info->status.ampdu_len = 1;
495 }
496
497 mi->ampdu_packets++;
498 mi->ampdu_len += info->status.ampdu_len;
499
500 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
501 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
502 mi->sample_tries = 1;
503 mi->sample_count--;
504 }
505
506 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
507 mi->sample_packets += info->status.ampdu_len;
508
509 last = !minstrel_ht_txstat_valid(mp, &ar[0]);
510 for (i = 0; !last; i++) {
511 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
512 !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
513
514 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
515
516 if (last)
517 rate->success += info->status.ampdu_ack_len;
518
519 rate->attempts += ar[i].count * info->status.ampdu_len;
520 }
521
522 /*
523 * check for sudden death of spatial multiplexing,
524 * downgrade to a lower number of streams if necessary.
525 */
526 rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
527 if (rate->attempts > 30 &&
528 MINSTREL_FRAC(rate->success, rate->attempts) <
529 MINSTREL_FRAC(20, 100)) {
530 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
531 update = true;
532 }
533
534 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
535 if (rate2->attempts > 30 &&
536 MINSTREL_FRAC(rate2->success, rate2->attempts) <
537 MINSTREL_FRAC(20, 100)) {
538 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
539 update = true;
540 }
541
542 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
543 update = true;
544 minstrel_ht_update_stats(mp, mi);
545 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
546 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
547 minstrel_aggr_check(sta, skb);
548 }
549
550 if (update)
551 minstrel_ht_update_rates(mp, mi);
552 }
553
554 static void
555 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
556 int index)
557 {
558 struct minstrel_rate_stats *mr;
559 const struct mcs_group *group;
560 unsigned int tx_time, tx_time_rtscts, tx_time_data;
561 unsigned int cw = mp->cw_min;
562 unsigned int ctime = 0;
563 unsigned int t_slot = 9; /* FIXME */
564 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
565 unsigned int overhead = 0, overhead_rtscts = 0;
566
567 mr = minstrel_get_ratestats(mi, index);
568 if (mr->probability < MINSTREL_FRAC(1, 10)) {
569 mr->retry_count = 1;
570 mr->retry_count_rtscts = 1;
571 return;
572 }
573
574 mr->retry_count = 2;
575 mr->retry_count_rtscts = 2;
576 mr->retry_updated = true;
577
578 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
579 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
580
581 /* Contention time for first 2 tries */
582 ctime = (t_slot * cw) >> 1;
583 cw = min((cw << 1) | 1, mp->cw_max);
584 ctime += (t_slot * cw) >> 1;
585 cw = min((cw << 1) | 1, mp->cw_max);
586
587 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
588 overhead = mi->overhead;
589 overhead_rtscts = mi->overhead_rtscts;
590 }
591
592 /* Total TX time for data and Contention after first 2 tries */
593 tx_time = ctime + 2 * (overhead + tx_time_data);
594 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
595
596 /* See how many more tries we can fit inside segment size */
597 do {
598 /* Contention time for this try */
599 ctime = (t_slot * cw) >> 1;
600 cw = min((cw << 1) | 1, mp->cw_max);
601
602 /* Total TX time after this try */
603 tx_time += ctime + overhead + tx_time_data;
604 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
605
606 if (tx_time_rtscts < mp->segment_size)
607 mr->retry_count_rtscts++;
608 } while ((tx_time < mp->segment_size) &&
609 (++mr->retry_count < mp->max_retry));
610 }
611
612
613 static void
614 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
615 struct ieee80211_sta_rates *ratetbl, int offset, int index)
616 {
617 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
618 struct minstrel_rate_stats *mr;
619 u8 idx;
620 u16 flags;
621
622 mr = minstrel_get_ratestats(mi, index);
623 if (!mr->retry_updated)
624 minstrel_calc_retransmit(mp, mi, index);
625
626 if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) {
627 ratetbl->rate[offset].count = 2;
628 ratetbl->rate[offset].count_rts = 2;
629 ratetbl->rate[offset].count_cts = 2;
630 } else {
631 ratetbl->rate[offset].count = mr->retry_count;
632 ratetbl->rate[offset].count_cts = mr->retry_count;
633 ratetbl->rate[offset].count_rts = mr->retry_count_rtscts;
634 }
635
636 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
637 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
638 flags = 0;
639 } else {
640 idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;
641 flags = IEEE80211_TX_RC_MCS | group->flags;
642 }
643
644 if (offset > 0) {
645 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
646 flags |= IEEE80211_TX_RC_USE_RTS_CTS;
647 }
648
649 ratetbl->rate[offset].idx = idx;
650 ratetbl->rate[offset].flags = flags;
651 }
652
653 static void
654 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
655 {
656 struct ieee80211_sta_rates *rates;
657 int i = 0;
658
659 rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
660 if (!rates)
661 return;
662
663 /* Start with max_tp_rate */
664 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate);
665
666 if (mp->hw->max_rates >= 3) {
667 /* At least 3 tx rates supported, use max_tp_rate2 next */
668 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate2);
669 }
670
671 if (mp->hw->max_rates >= 2) {
672 /*
673 * At least 2 tx rates supported, use max_prob_rate next */
674 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
675 }
676
677 rates->rate[i].idx = -1;
678 rate_control_set_rates(mp->hw, mi->sta, rates);
679 }
680
681 static inline int
682 minstrel_get_duration(int index)
683 {
684 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
685 return group->duration[index % MCS_GROUP_RATES];
686 }
687
688 static int
689 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
690 {
691 struct minstrel_rate_stats *mr;
692 struct minstrel_mcs_group_data *mg;
693 unsigned int sample_dur, sample_group;
694 int sample_idx = 0;
695
696 if (mi->sample_wait > 0) {
697 mi->sample_wait--;
698 return -1;
699 }
700
701 if (!mi->sample_tries)
702 return -1;
703
704 sample_group = mi->sample_group;
705 mg = &mi->groups[sample_group];
706 sample_idx = sample_table[mg->column][mg->index];
707 minstrel_next_sample_idx(mi);
708
709 if (!(mg->supported & BIT(sample_idx)))
710 return -1;
711
712 mr = &mg->rates[sample_idx];
713 sample_idx += sample_group * MCS_GROUP_RATES;
714
715 /*
716 * Sampling might add some overhead (RTS, no aggregation)
717 * to the frame. Hence, don't use sampling for the currently
718 * used rates.
719 */
720 if (sample_idx == mi->max_tp_rate ||
721 sample_idx == mi->max_tp_rate2 ||
722 sample_idx == mi->max_prob_rate)
723 return -1;
724
725 /*
726 * Do not sample if the probability is already higher than 95%
727 * to avoid wasting airtime.
728 */
729 if (mr->probability > MINSTREL_FRAC(95, 100))
730 return -1;
731
732 /*
733 * Make sure that lower rates get sampled only occasionally,
734 * if the link is working perfectly.
735 */
736 sample_dur = minstrel_get_duration(sample_idx);
737 if (sample_dur >= minstrel_get_duration(mi->max_tp_rate2) &&
738 (mi->max_prob_streams <
739 minstrel_mcs_groups[sample_group].streams ||
740 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
741 if (mr->sample_skipped < 20)
742 return -1;
743
744 if (mi->sample_slow++ > 2)
745 return -1;
746 }
747 mi->sample_tries--;
748
749 return sample_idx;
750 }
751
752 static void
753 minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp,
754 struct minstrel_ht_sta *mi, bool val)
755 {
756 u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported;
757
758 if (!supported || !mi->cck_supported_short)
759 return;
760
761 if (supported & (mi->cck_supported_short << (val * 4)))
762 return;
763
764 supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4);
765 mi->groups[MINSTREL_CCK_GROUP].supported = supported;
766 }
767
768 static void
769 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
770 struct ieee80211_tx_rate_control *txrc)
771 {
772 const struct mcs_group *sample_group;
773 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
774 struct ieee80211_tx_rate *rate = &info->status.rates[0];
775 struct minstrel_ht_sta_priv *msp = priv_sta;
776 struct minstrel_ht_sta *mi = &msp->ht;
777 struct minstrel_priv *mp = priv;
778 int sample_idx;
779
780 if (rate_control_send_low(sta, priv_sta, txrc))
781 return;
782
783 if (!msp->is_ht)
784 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
785
786 info->flags |= mi->tx_flags;
787 minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble);
788
789 #ifdef CONFIG_MAC80211_DEBUGFS
790 if (mp->fixed_rate_idx != -1)
791 return;
792 #endif
793
794 /* Don't use EAPOL frames for sampling on non-mrr hw */
795 if (mp->hw->max_rates == 1 &&
796 (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
797 sample_idx = -1;
798 else
799 sample_idx = minstrel_get_sample_rate(mp, mi);
800
801 mi->total_packets++;
802
803 /* wraparound */
804 if (mi->total_packets == ~0) {
805 mi->total_packets = 0;
806 mi->sample_packets = 0;
807 }
808
809 if (sample_idx < 0)
810 return;
811
812 sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
813 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
814 rate->count = 1;
815
816 if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
817 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
818 rate->idx = mp->cck_rates[idx];
819 rate->flags = 0;
820 return;
821 }
822
823 rate->idx = sample_idx % MCS_GROUP_RATES +
824 (sample_group->streams - 1) * 8;
825 rate->flags = IEEE80211_TX_RC_MCS | sample_group->flags;
826 }
827
828 static void
829 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
830 struct ieee80211_supported_band *sband,
831 struct ieee80211_sta *sta)
832 {
833 int i;
834
835 if (sband->band != IEEE80211_BAND_2GHZ)
836 return;
837
838 if (!(mp->hw->flags & IEEE80211_HW_SUPPORTS_HT_CCK_RATES))
839 return;
840
841 mi->cck_supported = 0;
842 mi->cck_supported_short = 0;
843 for (i = 0; i < 4; i++) {
844 if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
845 continue;
846
847 mi->cck_supported |= BIT(i);
848 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
849 mi->cck_supported_short |= BIT(i);
850 }
851
852 mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported;
853 }
854
855 static void
856 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
857 struct cfg80211_chan_def *chandef,
858 struct ieee80211_sta *sta, void *priv_sta)
859 {
860 struct minstrel_priv *mp = priv;
861 struct minstrel_ht_sta_priv *msp = priv_sta;
862 struct minstrel_ht_sta *mi = &msp->ht;
863 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
864 u16 sta_cap = sta->ht_cap.cap;
865 int n_supported = 0;
866 int ack_dur;
867 int stbc;
868 int i;
869
870 /* fall back to the old minstrel for legacy stations */
871 if (!sta->ht_cap.ht_supported)
872 goto use_legacy;
873
874 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
875 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1);
876
877 msp->is_ht = true;
878 memset(mi, 0, sizeof(*mi));
879
880 mi->sta = sta;
881 mi->stats_update = jiffies;
882
883 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
884 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
885 mi->overhead += ack_dur;
886 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
887
888 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
889
890 /* When using MRR, sample more on the first attempt, without delay */
891 if (mp->has_mrr) {
892 mi->sample_count = 16;
893 mi->sample_wait = 0;
894 } else {
895 mi->sample_count = 8;
896 mi->sample_wait = 8;
897 }
898 mi->sample_tries = 4;
899
900 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
901 IEEE80211_HT_CAP_RX_STBC_SHIFT;
902 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
903
904 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
905 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
906
907 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
908 mi->groups[i].supported = 0;
909 if (i == MINSTREL_CCK_GROUP) {
910 minstrel_ht_update_cck(mp, mi, sband, sta);
911 continue;
912 }
913
914 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
915 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
916 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
917 continue;
918 } else {
919 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
920 continue;
921 }
922 }
923
924 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
925 sta->bandwidth < IEEE80211_STA_RX_BW_40)
926 continue;
927
928 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
929 if (sta->smps_mode == IEEE80211_SMPS_STATIC &&
930 minstrel_mcs_groups[i].streams > 1)
931 continue;
932
933 mi->groups[i].supported =
934 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
935
936 if (mi->groups[i].supported)
937 n_supported++;
938 }
939
940 if (!n_supported)
941 goto use_legacy;
942
943 /* create an initial rate table with the lowest supported rates */
944 minstrel_ht_update_stats(mp, mi);
945 minstrel_ht_update_rates(mp, mi);
946
947 return;
948
949 use_legacy:
950 msp->is_ht = false;
951 memset(&msp->legacy, 0, sizeof(msp->legacy));
952 msp->legacy.r = msp->ratelist;
953 msp->legacy.sample_table = msp->sample_table;
954 return mac80211_minstrel.rate_init(priv, sband, chandef, sta,
955 &msp->legacy);
956 }
957
958 static void
959 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
960 struct cfg80211_chan_def *chandef,
961 struct ieee80211_sta *sta, void *priv_sta)
962 {
963 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
964 }
965
966 static void
967 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
968 struct cfg80211_chan_def *chandef,
969 struct ieee80211_sta *sta, void *priv_sta,
970 u32 changed)
971 {
972 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
973 }
974
975 static void *
976 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
977 {
978 struct ieee80211_supported_band *sband;
979 struct minstrel_ht_sta_priv *msp;
980 struct minstrel_priv *mp = priv;
981 struct ieee80211_hw *hw = mp->hw;
982 int max_rates = 0;
983 int i;
984
985 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
986 sband = hw->wiphy->bands[i];
987 if (sband && sband->n_bitrates > max_rates)
988 max_rates = sband->n_bitrates;
989 }
990
991 msp = kzalloc(sizeof(*msp), gfp);
992 if (!msp)
993 return NULL;
994
995 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
996 if (!msp->ratelist)
997 goto error;
998
999 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
1000 if (!msp->sample_table)
1001 goto error1;
1002
1003 return msp;
1004
1005 error1:
1006 kfree(msp->ratelist);
1007 error:
1008 kfree(msp);
1009 return NULL;
1010 }
1011
1012 static void
1013 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1014 {
1015 struct minstrel_ht_sta_priv *msp = priv_sta;
1016
1017 kfree(msp->sample_table);
1018 kfree(msp->ratelist);
1019 kfree(msp);
1020 }
1021
1022 static void *
1023 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
1024 {
1025 return mac80211_minstrel.alloc(hw, debugfsdir);
1026 }
1027
1028 static void
1029 minstrel_ht_free(void *priv)
1030 {
1031 mac80211_minstrel.free(priv);
1032 }
1033
1034 static struct rate_control_ops mac80211_minstrel_ht = {
1035 .name = "minstrel_ht",
1036 .tx_status = minstrel_ht_tx_status,
1037 .get_rate = minstrel_ht_get_rate,
1038 .rate_init = minstrel_ht_rate_init,
1039 .rate_update = minstrel_ht_rate_update,
1040 .alloc_sta = minstrel_ht_alloc_sta,
1041 .free_sta = minstrel_ht_free_sta,
1042 .alloc = minstrel_ht_alloc,
1043 .free = minstrel_ht_free,
1044 #ifdef CONFIG_MAC80211_DEBUGFS
1045 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
1046 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
1047 #endif
1048 };
1049
1050
1051 static void
1052 init_sample_table(void)
1053 {
1054 int col, i, new_idx;
1055 u8 rnd[MCS_GROUP_RATES];
1056
1057 memset(sample_table, 0xff, sizeof(sample_table));
1058 for (col = 0; col < SAMPLE_COLUMNS; col++) {
1059 prandom_bytes(rnd, sizeof(rnd));
1060 for (i = 0; i < MCS_GROUP_RATES; i++) {
1061 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1062 while (sample_table[col][new_idx] != 0xff)
1063 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1064
1065 sample_table[col][new_idx] = i;
1066 }
1067 }
1068 }
1069
1070 int __init
1071 rc80211_minstrel_ht_init(void)
1072 {
1073 init_sample_table();
1074 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1075 }
1076
1077 void
1078 rc80211_minstrel_ht_exit(void)
1079 {
1080 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
1081 }
Linux with added FPC-III support