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Btrfs: fix list transaction->pending_ordered corruption
[linux/fpc-iii.git] / net / mac80211 / rc80211_minstrel_ht.c
blob0f632d6c690479419ad56e99d1c81a8274861bd6
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 / MCS_GROUP_RATES) + 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 * Find & sort topmost throughput rates
237 *
238 * If multiple rates provide equal throughput the sorting is based on their
239 * current success probability. Higher success probability is preferred among
240 * MCS groups, CCK rates do not provide aggregation and are therefore at last.
241 */
242 static void
243 minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u8 index,
244 u8 *tp_list)
245 {
246 int cur_group, cur_idx, cur_thr, cur_prob;
247 int tmp_group, tmp_idx, tmp_thr, tmp_prob;
248 int j = MAX_THR_RATES;
249
250 cur_group = index / MCS_GROUP_RATES;
251 cur_idx = index % MCS_GROUP_RATES;
252 cur_thr = mi->groups[cur_group].rates[cur_idx].cur_tp;
253 cur_prob = mi->groups[cur_group].rates[cur_idx].probability;
254
255 do {
256 tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
257 tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
258 tmp_thr = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
259 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability;
260 if (cur_thr < tmp_thr ||
261 (cur_thr == tmp_thr && cur_prob <= tmp_prob))
262 break;
263 j--;
264 } while (j > 0);
265
266 if (j < MAX_THR_RATES - 1) {
267 memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) *
268 (MAX_THR_RATES - (j + 1))));
269 }
270 if (j < MAX_THR_RATES)
271 tp_list[j] = index;
272 }
273
274 /*
275 * Find and set the topmost probability rate per sta and per group
276 */
277 static void
278 minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u8 index)
279 {
280 struct minstrel_mcs_group_data *mg;
281 struct minstrel_rate_stats *mr;
282 int tmp_group, tmp_idx, tmp_tp, tmp_prob, max_tp_group;
283
284 mg = &mi->groups[index / MCS_GROUP_RATES];
285 mr = &mg->rates[index % MCS_GROUP_RATES];
286
287 tmp_group = mi->max_prob_rate / MCS_GROUP_RATES;
288 tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES;
289 tmp_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
290 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability;
291
292 /* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
293 * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
294 max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES;
295 if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) &&
296 (max_tp_group != MINSTREL_CCK_GROUP))
297 return;
298
299 if (mr->probability > MINSTREL_FRAC(75, 100)) {
300 if (mr->cur_tp > tmp_tp)
301 mi->max_prob_rate = index;
302 if (mr->cur_tp > mg->rates[mg->max_group_prob_rate].cur_tp)
303 mg->max_group_prob_rate = index;
304 } else {
305 if (mr->probability > tmp_prob)
306 mi->max_prob_rate = index;
307 if (mr->probability > mg->rates[mg->max_group_prob_rate].probability)
308 mg->max_group_prob_rate = index;
309 }
310 }
311
312
313 /*
314 * Assign new rate set per sta and use CCK rates only if the fastest
315 * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted
316 * rate sets where MCS and CCK rates are mixed, because CCK rates can
317 * not use aggregation.
318 */
319 static void
320 minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi,
321 u8 tmp_mcs_tp_rate[MAX_THR_RATES],
322 u8 tmp_cck_tp_rate[MAX_THR_RATES])
323 {
324 unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp;
325 int i;
326
327 tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES;
328 tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES;
329 tmp_cck_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
330
331 tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES;
332 tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES;
333 tmp_mcs_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
334
335 if (tmp_cck_tp > tmp_mcs_tp) {
336 for(i = 0; i < MAX_THR_RATES; i++) {
337 minstrel_ht_sort_best_tp_rates(mi, tmp_cck_tp_rate[i],
338 tmp_mcs_tp_rate);
339 }
340 }
341
342 }
343
344 /*
345 * Try to increase robustness of max_prob rate by decrease number of
346 * streams if possible.
347 */
348 static inline void
349 minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
350 {
351 struct minstrel_mcs_group_data *mg;
352 struct minstrel_rate_stats *mr;
353 int tmp_max_streams, group;
354 int tmp_tp = 0;
355
356 tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
357 MCS_GROUP_RATES].streams;
358 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
359 mg = &mi->groups[group];
360 if (!mg->supported || group == MINSTREL_CCK_GROUP)
361 continue;
362 mr = minstrel_get_ratestats(mi, mg->max_group_prob_rate);
363 if (tmp_tp < mr->cur_tp &&
364 (minstrel_mcs_groups[group].streams < tmp_max_streams)) {
365 mi->max_prob_rate = mg->max_group_prob_rate;
366 tmp_tp = mr->cur_tp;
367 }
368 }
369 }
370
371 /*
372 * Update rate statistics and select new primary rates
373 *
374 * Rules for rate selection:
375 * - max_prob_rate must use only one stream, as a tradeoff between delivery
376 * probability and throughput during strong fluctuations
377 * - as long as the max prob rate has a probability of more than 75%, pick
378 * higher throughput rates, even if the probablity is a bit lower
379 */
380 static void
381 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
382 {
383 struct minstrel_mcs_group_data *mg;
384 struct minstrel_rate_stats *mr;
385 int group, i, j;
386 u8 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
387 u8 tmp_cck_tp_rate[MAX_THR_RATES], index;
388
389 if (mi->ampdu_packets > 0) {
390 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
391 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
392 mi->ampdu_len = 0;
393 mi->ampdu_packets = 0;
394 }
395
396 mi->sample_slow = 0;
397 mi->sample_count = 0;
398
399 /* Initialize global rate indexes */
400 for(j = 0; j < MAX_THR_RATES; j++){
401 tmp_mcs_tp_rate[j] = 0;
402 tmp_cck_tp_rate[j] = 0;
403 }
404
405 /* Find best rate sets within all MCS groups*/
406 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
407
408 mg = &mi->groups[group];
409 if (!mg->supported)
410 continue;
411
412 mi->sample_count++;
413
414 /* (re)Initialize group rate indexes */
415 for(j = 0; j < MAX_THR_RATES; j++)
416 tmp_group_tp_rate[j] = group;
417
418 for (i = 0; i < MCS_GROUP_RATES; i++) {
419 if (!(mg->supported & BIT(i)))
420 continue;
421
422 index = MCS_GROUP_RATES * group + i;
423
424 mr = &mg->rates[i];
425 mr->retry_updated = false;
426 minstrel_calc_rate_ewma(mr);
427 minstrel_ht_calc_tp(mi, group, i);
428
429 if (!mr->cur_tp)
430 continue;
431
432 /* Find max throughput rate set */
433 if (group != MINSTREL_CCK_GROUP) {
434 minstrel_ht_sort_best_tp_rates(mi, index,
435 tmp_mcs_tp_rate);
436 } else if (group == MINSTREL_CCK_GROUP) {
437 minstrel_ht_sort_best_tp_rates(mi, index,
438 tmp_cck_tp_rate);
439 }
440
441 /* Find max throughput rate set within a group */
442 minstrel_ht_sort_best_tp_rates(mi, index,
443 tmp_group_tp_rate);
444
445 /* Find max probability rate per group and global */
446 minstrel_ht_set_best_prob_rate(mi, index);
447 }
448
449 memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
450 sizeof(mg->max_group_tp_rate));
451 }
452
453 /* Assign new rate set per sta */
454 minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate);
455 memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));
456
457 /* Try to increase robustness of max_prob_rate*/
458 minstrel_ht_prob_rate_reduce_streams(mi);
459
460 /* try to sample all available rates during each interval */
461 mi->sample_count *= 8;
462
463 #ifdef CONFIG_MAC80211_DEBUGFS
464 /* use fixed index if set */
465 if (mp->fixed_rate_idx != -1) {
466 for (i = 0; i < 4; i++)
467 mi->max_tp_rate[i] = mp->fixed_rate_idx;
468 mi->max_prob_rate = mp->fixed_rate_idx;
469 }
470 #endif
471
472 /* Reset update timer */
473 mi->stats_update = jiffies;
474 }
475
476 static bool
477 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
478 {
479 if (rate->idx < 0)
480 return false;
481
482 if (!rate->count)
483 return false;
484
485 if (rate->flags & IEEE80211_TX_RC_MCS)
486 return true;
487
488 return rate->idx == mp->cck_rates[0] ||
489 rate->idx == mp->cck_rates[1] ||
490 rate->idx == mp->cck_rates[2] ||
491 rate->idx == mp->cck_rates[3];
492 }
493
494 static void
495 minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
496 {
497 struct minstrel_mcs_group_data *mg;
498
499 for (;;) {
500 mi->sample_group++;
501 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
502 mg = &mi->groups[mi->sample_group];
503
504 if (!mg->supported)
505 continue;
506
507 if (++mg->index >= MCS_GROUP_RATES) {
508 mg->index = 0;
509 if (++mg->column >= ARRAY_SIZE(sample_table))
510 mg->column = 0;
511 }
512 break;
513 }
514 }
515
516 static void
517 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u8 *idx, bool primary)
518 {
519 int group, orig_group;
520
521 orig_group = group = *idx / MCS_GROUP_RATES;
522 while (group > 0) {
523 group--;
524
525 if (!mi->groups[group].supported)
526 continue;
527
528 if (minstrel_mcs_groups[group].streams >
529 minstrel_mcs_groups[orig_group].streams)
530 continue;
531
532 if (primary)
533 *idx = mi->groups[group].max_group_tp_rate[0];
534 else
535 *idx = mi->groups[group].max_group_tp_rate[1];
536 break;
537 }
538 }
539
540 static void
541 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
542 {
543 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
544 struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
545 u16 tid;
546
547 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
548 return;
549
550 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
551 return;
552
553 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
554 if (likely(sta->ampdu_mlme.tid_tx[tid]))
555 return;
556
557 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
558 return;
559
560 ieee80211_start_tx_ba_session(pubsta, tid, 0);
561 }
562
563 static void
564 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
565 struct ieee80211_sta *sta, void *priv_sta,
566 struct sk_buff *skb)
567 {
568 struct minstrel_ht_sta_priv *msp = priv_sta;
569 struct minstrel_ht_sta *mi = &msp->ht;
570 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
571 struct ieee80211_tx_rate *ar = info->status.rates;
572 struct minstrel_rate_stats *rate, *rate2;
573 struct minstrel_priv *mp = priv;
574 bool last, update = false;
575 int i;
576
577 if (!msp->is_ht)
578 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
579
580 /* This packet was aggregated but doesn't carry status info */
581 if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
582 !(info->flags & IEEE80211_TX_STAT_AMPDU))
583 return;
584
585 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
586 info->status.ampdu_ack_len =
587 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
588 info->status.ampdu_len = 1;
589 }
590
591 mi->ampdu_packets++;
592 mi->ampdu_len += info->status.ampdu_len;
593
594 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
595 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
596 mi->sample_tries = 1;
597 mi->sample_count--;
598 }
599
600 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
601 mi->sample_packets += info->status.ampdu_len;
602
603 last = !minstrel_ht_txstat_valid(mp, &ar[0]);
604 for (i = 0; !last; i++) {
605 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
606 !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
607
608 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
609
610 if (last)
611 rate->success += info->status.ampdu_ack_len;
612
613 rate->attempts += ar[i].count * info->status.ampdu_len;
614 }
615
616 /*
617 * check for sudden death of spatial multiplexing,
618 * downgrade to a lower number of streams if necessary.
619 */
620 rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
621 if (rate->attempts > 30 &&
622 MINSTREL_FRAC(rate->success, rate->attempts) <
623 MINSTREL_FRAC(20, 100)) {
624 minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
625 update = true;
626 }
627
628 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
629 if (rate2->attempts > 30 &&
630 MINSTREL_FRAC(rate2->success, rate2->attempts) <
631 MINSTREL_FRAC(20, 100)) {
632 minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
633 update = true;
634 }
635
636 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
637 update = true;
638 minstrel_ht_update_stats(mp, mi);
639 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
640 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
641 minstrel_aggr_check(sta, skb);
642 }
643
644 if (update)
645 minstrel_ht_update_rates(mp, mi);
646 }
647
648 static void
649 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
650 int index)
651 {
652 struct minstrel_rate_stats *mr;
653 const struct mcs_group *group;
654 unsigned int tx_time, tx_time_rtscts, tx_time_data;
655 unsigned int cw = mp->cw_min;
656 unsigned int ctime = 0;
657 unsigned int t_slot = 9; /* FIXME */
658 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
659 unsigned int overhead = 0, overhead_rtscts = 0;
660
661 mr = minstrel_get_ratestats(mi, index);
662 if (mr->probability < MINSTREL_FRAC(1, 10)) {
663 mr->retry_count = 1;
664 mr->retry_count_rtscts = 1;
665 return;
666 }
667
668 mr->retry_count = 2;
669 mr->retry_count_rtscts = 2;
670 mr->retry_updated = true;
671
672 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
673 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
674
675 /* Contention time for first 2 tries */
676 ctime = (t_slot * cw) >> 1;
677 cw = min((cw << 1) | 1, mp->cw_max);
678 ctime += (t_slot * cw) >> 1;
679 cw = min((cw << 1) | 1, mp->cw_max);
680
681 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
682 overhead = mi->overhead;
683 overhead_rtscts = mi->overhead_rtscts;
684 }
685
686 /* Total TX time for data and Contention after first 2 tries */
687 tx_time = ctime + 2 * (overhead + tx_time_data);
688 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
689
690 /* See how many more tries we can fit inside segment size */
691 do {
692 /* Contention time for this try */
693 ctime = (t_slot * cw) >> 1;
694 cw = min((cw << 1) | 1, mp->cw_max);
695
696 /* Total TX time after this try */
697 tx_time += ctime + overhead + tx_time_data;
698 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
699
700 if (tx_time_rtscts < mp->segment_size)
701 mr->retry_count_rtscts++;
702 } while ((tx_time < mp->segment_size) &&
703 (++mr->retry_count < mp->max_retry));
704 }
705
706
707 static void
708 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
709 struct ieee80211_sta_rates *ratetbl, int offset, int index)
710 {
711 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
712 struct minstrel_rate_stats *mr;
713 u8 idx;
714 u16 flags;
715
716 mr = minstrel_get_ratestats(mi, index);
717 if (!mr->retry_updated)
718 minstrel_calc_retransmit(mp, mi, index);
719
720 if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) {
721 ratetbl->rate[offset].count = 2;
722 ratetbl->rate[offset].count_rts = 2;
723 ratetbl->rate[offset].count_cts = 2;
724 } else {
725 ratetbl->rate[offset].count = mr->retry_count;
726 ratetbl->rate[offset].count_cts = mr->retry_count;
727 ratetbl->rate[offset].count_rts = mr->retry_count_rtscts;
728 }
729
730 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
731 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
732 flags = 0;
733 } else {
734 idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;
735 flags = IEEE80211_TX_RC_MCS | group->flags;
736 }
737
738 if (offset > 0) {
739 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
740 flags |= IEEE80211_TX_RC_USE_RTS_CTS;
741 }
742
743 ratetbl->rate[offset].idx = idx;
744 ratetbl->rate[offset].flags = flags;
745 }
746
747 static void
748 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
749 {
750 struct ieee80211_sta_rates *rates;
751 int i = 0;
752
753 rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
754 if (!rates)
755 return;
756
757 /* Start with max_tp_rate[0] */
758 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
759
760 if (mp->hw->max_rates >= 3) {
761 /* At least 3 tx rates supported, use max_tp_rate[1] next */
762 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]);
763 }
764
765 if (mp->hw->max_rates >= 2) {
766 /*
767 * At least 2 tx rates supported, use max_prob_rate next */
768 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
769 }
770
771 rates->rate[i].idx = -1;
772 rate_control_set_rates(mp->hw, mi->sta, rates);
773 }
774
775 static inline int
776 minstrel_get_duration(int index)
777 {
778 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
779 return group->duration[index % MCS_GROUP_RATES];
780 }
781
782 static int
783 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
784 {
785 struct minstrel_rate_stats *mr;
786 struct minstrel_mcs_group_data *mg;
787 unsigned int sample_dur, sample_group, cur_max_tp_streams;
788 int sample_idx = 0;
789
790 if (mi->sample_wait > 0) {
791 mi->sample_wait--;
792 return -1;
793 }
794
795 if (!mi->sample_tries)
796 return -1;
797
798 sample_group = mi->sample_group;
799 mg = &mi->groups[sample_group];
800 sample_idx = sample_table[mg->column][mg->index];
801 minstrel_next_sample_idx(mi);
802
803 if (!(mg->supported & BIT(sample_idx)))
804 return -1;
805
806 mr = &mg->rates[sample_idx];
807 sample_idx += sample_group * MCS_GROUP_RATES;
808
809 /*
810 * Sampling might add some overhead (RTS, no aggregation)
811 * to the frame. Hence, don't use sampling for the currently
812 * used rates.
813 */
814 if (sample_idx == mi->max_tp_rate[0] ||
815 sample_idx == mi->max_tp_rate[1] ||
816 sample_idx == mi->max_prob_rate)
817 return -1;
818
819 /*
820 * Do not sample if the probability is already higher than 95%
821 * to avoid wasting airtime.
822 */
823 if (mr->probability > MINSTREL_FRAC(95, 100))
824 return -1;
825
826 /*
827 * Make sure that lower rates get sampled only occasionally,
828 * if the link is working perfectly.
829 */
830
831 cur_max_tp_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
832 MCS_GROUP_RATES].streams;
833 sample_dur = minstrel_get_duration(sample_idx);
834 if (sample_dur >= minstrel_get_duration(mi->max_tp_rate[1]) &&
835 (cur_max_tp_streams - 1 <
836 minstrel_mcs_groups[sample_group].streams ||
837 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
838 if (mr->sample_skipped < 20)
839 return -1;
840
841 if (mi->sample_slow++ > 2)
842 return -1;
843 }
844 mi->sample_tries--;
845
846 return sample_idx;
847 }
848
849 static void
850 minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp,
851 struct minstrel_ht_sta *mi, bool val)
852 {
853 u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported;
854
855 if (!supported || !mi->cck_supported_short)
856 return;
857
858 if (supported & (mi->cck_supported_short << (val * 4)))
859 return;
860
861 supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4);
862 mi->groups[MINSTREL_CCK_GROUP].supported = supported;
863 }
864
865 static void
866 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
867 struct ieee80211_tx_rate_control *txrc)
868 {
869 const struct mcs_group *sample_group;
870 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
871 struct ieee80211_tx_rate *rate = &info->status.rates[0];
872 struct minstrel_ht_sta_priv *msp = priv_sta;
873 struct minstrel_ht_sta *mi = &msp->ht;
874 struct minstrel_priv *mp = priv;
875 int sample_idx;
876
877 if (rate_control_send_low(sta, priv_sta, txrc))
878 return;
879
880 if (!msp->is_ht)
881 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
882
883 info->flags |= mi->tx_flags;
884 minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble);
885
886 #ifdef CONFIG_MAC80211_DEBUGFS
887 if (mp->fixed_rate_idx != -1)
888 return;
889 #endif
890
891 /* Don't use EAPOL frames for sampling on non-mrr hw */
892 if (mp->hw->max_rates == 1 &&
893 (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
894 sample_idx = -1;
895 else
896 sample_idx = minstrel_get_sample_rate(mp, mi);
897
898 mi->total_packets++;
899
900 /* wraparound */
901 if (mi->total_packets == ~0) {
902 mi->total_packets = 0;
903 mi->sample_packets = 0;
904 }
905
906 if (sample_idx < 0)
907 return;
908
909 sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
910 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
911 rate->count = 1;
912
913 if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
914 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
915 rate->idx = mp->cck_rates[idx];
916 rate->flags = 0;
917 return;
918 }
919
920 rate->idx = sample_idx % MCS_GROUP_RATES +
921 (sample_group->streams - 1) * 8;
922 rate->flags = IEEE80211_TX_RC_MCS | sample_group->flags;
923 }
924
925 static void
926 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
927 struct ieee80211_supported_band *sband,
928 struct ieee80211_sta *sta)
929 {
930 int i;
931
932 if (sband->band != IEEE80211_BAND_2GHZ)
933 return;
934
935 if (!(mp->hw->flags & IEEE80211_HW_SUPPORTS_HT_CCK_RATES))
936 return;
937
938 mi->cck_supported = 0;
939 mi->cck_supported_short = 0;
940 for (i = 0; i < 4; i++) {
941 if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
942 continue;
943
944 mi->cck_supported |= BIT(i);
945 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
946 mi->cck_supported_short |= BIT(i);
947 }
948
949 mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported;
950 }
951
952 static void
953 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
954 struct cfg80211_chan_def *chandef,
955 struct ieee80211_sta *sta, void *priv_sta)
956 {
957 struct minstrel_priv *mp = priv;
958 struct minstrel_ht_sta_priv *msp = priv_sta;
959 struct minstrel_ht_sta *mi = &msp->ht;
960 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
961 u16 sta_cap = sta->ht_cap.cap;
962 int n_supported = 0;
963 int ack_dur;
964 int stbc;
965 int i;
966
967 /* fall back to the old minstrel for legacy stations */
968 if (!sta->ht_cap.ht_supported)
969 goto use_legacy;
970
971 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
972 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1);
973
974 msp->is_ht = true;
975 memset(mi, 0, sizeof(*mi));
976
977 mi->sta = sta;
978 mi->stats_update = jiffies;
979
980 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
981 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
982 mi->overhead += ack_dur;
983 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
984
985 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
986
987 /* When using MRR, sample more on the first attempt, without delay */
988 if (mp->has_mrr) {
989 mi->sample_count = 16;
990 mi->sample_wait = 0;
991 } else {
992 mi->sample_count = 8;
993 mi->sample_wait = 8;
994 }
995 mi->sample_tries = 4;
996
997 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
998 IEEE80211_HT_CAP_RX_STBC_SHIFT;
999 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
1000
1001 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
1002 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
1003
1004 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
1005 mi->groups[i].supported = 0;
1006 if (i == MINSTREL_CCK_GROUP) {
1007 minstrel_ht_update_cck(mp, mi, sband, sta);
1008 continue;
1009 }
1010
1011 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
1012 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
1013 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
1014 continue;
1015 } else {
1016 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
1017 continue;
1018 }
1019 }
1020
1021 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
1022 sta->bandwidth < IEEE80211_STA_RX_BW_40)
1023 continue;
1024
1025 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
1026 if (sta->smps_mode == IEEE80211_SMPS_STATIC &&
1027 minstrel_mcs_groups[i].streams > 1)
1028 continue;
1029
1030 mi->groups[i].supported =
1031 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
1032
1033 if (mi->groups[i].supported)
1034 n_supported++;
1035 }
1036
1037 if (!n_supported)
1038 goto use_legacy;
1039
1040 /* create an initial rate table with the lowest supported rates */
1041 minstrel_ht_update_stats(mp, mi);
1042 minstrel_ht_update_rates(mp, mi);
1043
1044 return;
1045
1046 use_legacy:
1047 msp->is_ht = false;
1048 memset(&msp->legacy, 0, sizeof(msp->legacy));
1049 msp->legacy.r = msp->ratelist;
1050 msp->legacy.sample_table = msp->sample_table;
1051 return mac80211_minstrel.rate_init(priv, sband, chandef, sta,
1052 &msp->legacy);
1053 }
1054
1055 static void
1056 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
1057 struct cfg80211_chan_def *chandef,
1058 struct ieee80211_sta *sta, void *priv_sta)
1059 {
1060 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1061 }
1062
1063 static void
1064 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
1065 struct cfg80211_chan_def *chandef,
1066 struct ieee80211_sta *sta, void *priv_sta,
1067 u32 changed)
1068 {
1069 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1070 }
1071
1072 static void *
1073 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
1074 {
1075 struct ieee80211_supported_band *sband;
1076 struct minstrel_ht_sta_priv *msp;
1077 struct minstrel_priv *mp = priv;
1078 struct ieee80211_hw *hw = mp->hw;
1079 int max_rates = 0;
1080 int i;
1081
1082 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1083 sband = hw->wiphy->bands[i];
1084 if (sband && sband->n_bitrates > max_rates)
1085 max_rates = sband->n_bitrates;
1086 }
1087
1088 msp = kzalloc(sizeof(*msp), gfp);
1089 if (!msp)
1090 return NULL;
1091
1092 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
1093 if (!msp->ratelist)
1094 goto error;
1095
1096 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
1097 if (!msp->sample_table)
1098 goto error1;
1099
1100 return msp;
1101
1102 error1:
1103 kfree(msp->ratelist);
1104 error:
1105 kfree(msp);
1106 return NULL;
1107 }
1108
1109 static void
1110 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1111 {
1112 struct minstrel_ht_sta_priv *msp = priv_sta;
1113
1114 kfree(msp->sample_table);
1115 kfree(msp->ratelist);
1116 kfree(msp);
1117 }
1118
1119 static void *
1120 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
1121 {
1122 return mac80211_minstrel.alloc(hw, debugfsdir);
1123 }
1124
1125 static void
1126 minstrel_ht_free(void *priv)
1127 {
1128 mac80211_minstrel.free(priv);
1129 }
1130
1131 static u32 minstrel_ht_get_expected_throughput(void *priv_sta)
1132 {
1133 struct minstrel_ht_sta_priv *msp = priv_sta;
1134 struct minstrel_ht_sta *mi = &msp->ht;
1135 int i, j;
1136
1137 if (!msp->is_ht)
1138 return mac80211_minstrel.get_expected_throughput(priv_sta);
1139
1140 i = mi->max_tp_rate[0] / MCS_GROUP_RATES;
1141 j = mi->max_tp_rate[0] % MCS_GROUP_RATES;
1142
1143 /* convert cur_tp from pkt per second in kbps */
1144 return mi->groups[i].rates[j].cur_tp * AVG_PKT_SIZE * 8 / 1024;
1145 }
1146
1147 static const struct rate_control_ops mac80211_minstrel_ht = {
1148 .name = "minstrel_ht",
1149 .tx_status = minstrel_ht_tx_status,
1150 .get_rate = minstrel_ht_get_rate,
1151 .rate_init = minstrel_ht_rate_init,
1152 .rate_update = minstrel_ht_rate_update,
1153 .alloc_sta = minstrel_ht_alloc_sta,
1154 .free_sta = minstrel_ht_free_sta,
1155 .alloc = minstrel_ht_alloc,
1156 .free = minstrel_ht_free,
1157 #ifdef CONFIG_MAC80211_DEBUGFS
1158 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
1159 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
1160 #endif
1161 .get_expected_throughput = minstrel_ht_get_expected_throughput,
1162 };
1163
1164
1165 static void __init init_sample_table(void)
1166 {
1167 int col, i, new_idx;
1168 u8 rnd[MCS_GROUP_RATES];
1169
1170 memset(sample_table, 0xff, sizeof(sample_table));
1171 for (col = 0; col < SAMPLE_COLUMNS; col++) {
1172 prandom_bytes(rnd, sizeof(rnd));
1173 for (i = 0; i < MCS_GROUP_RATES; i++) {
1174 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1175 while (sample_table[col][new_idx] != 0xff)
1176 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1177
1178 sample_table[col][new_idx] = i;
1179 }
1180 }
1181 }
1182
1183 int __init
1184 rc80211_minstrel_ht_init(void)
1185 {
1186 init_sample_table();
1187 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1188 }
1189
1190 void
1191 rc80211_minstrel_ht_exit(void)
1192 {
1193 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
1194 }
Linux with added FPC-III support