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[media] em28xx: Improve support for the Terratec Cinergy HTC Stick HD
[linux-2.6/btrfs-unstable.git] / net / mac80211 / rc80211_minstrel_ht.c
blob16e0b277b9a865f440a734f2ff1f44ec267d0219
1 /*
2 * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8 #include <linux/netdevice.h>
9 #include <linux/types.h>
10 #include <linux/skbuff.h>
11 #include <linux/debugfs.h>
12 #include <linux/random.h>
13 #include <linux/ieee80211.h>
14 #include <net/mac80211.h>
15 #include "rate.h"
16 #include "rc80211_minstrel.h"
17 #include "rc80211_minstrel_ht.h"
18
19 #define AVG_PKT_SIZE 1200
20 #define SAMPLE_COLUMNS 10
21 #define EWMA_LEVEL 75
22
23 /* Number of bits for an average sized packet */
24 #define MCS_NBITS (AVG_PKT_SIZE << 3)
25
26 /* Number of symbols for a packet with (bps) bits per symbol */
27 #define MCS_NSYMS(bps) ((MCS_NBITS + (bps) - 1) / (bps))
28
29 /* Transmission time for a packet containing (syms) symbols */
30 #define MCS_SYMBOL_TIME(sgi, syms) \
31 (sgi ? \
32 ((syms) * 18 + 4) / 5 : /* syms * 3.6 us */ \
33 (syms) << 2 /* syms * 4 us */ \
34 )
35
36 /* Transmit duration for the raw data part of an average sized packet */
37 #define MCS_DURATION(streams, sgi, bps) MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps)))
38
39 /*
40 * Define group sort order: HT40 -> SGI -> #streams
41 */
42 #define GROUP_IDX(_streams, _sgi, _ht40) \
43 MINSTREL_MAX_STREAMS * 2 * _ht40 + \
44 MINSTREL_MAX_STREAMS * _sgi + \
45 _streams - 1
46
47 /* MCS rate information for an MCS group */
48 #define MCS_GROUP(_streams, _sgi, _ht40) \
49 [GROUP_IDX(_streams, _sgi, _ht40)] = { \
50 .streams = _streams, \
51 .flags = \
52 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
53 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
54 .duration = { \
55 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \
56 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \
57 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \
58 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \
59 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \
60 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \
61 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \
62 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \
63 } \
64 }
65
66 /*
67 * To enable sufficiently targeted rate sampling, MCS rates are divided into
68 * groups, based on the number of streams and flags (HT40, SGI) that they
69 * use.
70 *
71 * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
72 * HT40 -> SGI -> #streams
73 */
74 const struct mcs_group minstrel_mcs_groups[] = {
75 MCS_GROUP(1, 0, 0),
76 MCS_GROUP(2, 0, 0),
77 #if MINSTREL_MAX_STREAMS >= 3
78 MCS_GROUP(3, 0, 0),
79 #endif
80
81 MCS_GROUP(1, 1, 0),
82 MCS_GROUP(2, 1, 0),
83 #if MINSTREL_MAX_STREAMS >= 3
84 MCS_GROUP(3, 1, 0),
85 #endif
86
87 MCS_GROUP(1, 0, 1),
88 MCS_GROUP(2, 0, 1),
89 #if MINSTREL_MAX_STREAMS >= 3
90 MCS_GROUP(3, 0, 1),
91 #endif
92
93 MCS_GROUP(1, 1, 1),
94 MCS_GROUP(2, 1, 1),
95 #if MINSTREL_MAX_STREAMS >= 3
96 MCS_GROUP(3, 1, 1),
97 #endif
98 };
99
100 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES];
101
102 /*
103 * Perform EWMA (Exponentially Weighted Moving Average) calculation
104 */
105 static int
106 minstrel_ewma(int old, int new, int weight)
107 {
108 return (new * (100 - weight) + old * weight) / 100;
109 }
110
111 /*
112 * Look up an MCS group index based on mac80211 rate information
113 */
114 static int
115 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
116 {
117 return GROUP_IDX((rate->idx / MCS_GROUP_RATES) + 1,
118 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
119 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
120 }
121
122 static inline struct minstrel_rate_stats *
123 minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
124 {
125 return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
126 }
127
128
129 /*
130 * Recalculate success probabilities and counters for a rate using EWMA
131 */
132 static void
133 minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr)
134 {
135 if (unlikely(mr->attempts > 0)) {
136 mr->sample_skipped = 0;
137 mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
138 if (!mr->att_hist)
139 mr->probability = mr->cur_prob;
140 else
141 mr->probability = minstrel_ewma(mr->probability,
142 mr->cur_prob, EWMA_LEVEL);
143 mr->att_hist += mr->attempts;
144 mr->succ_hist += mr->success;
145 } else {
146 mr->sample_skipped++;
147 }
148 mr->last_success = mr->success;
149 mr->last_attempts = mr->attempts;
150 mr->success = 0;
151 mr->attempts = 0;
152 }
153
154 /*
155 * Calculate throughput based on the average A-MPDU length, taking into account
156 * the expected number of retransmissions and their expected length
157 */
158 static void
159 minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
160 {
161 struct minstrel_rate_stats *mr;
162 unsigned int usecs;
163
164 mr = &mi->groups[group].rates[rate];
165
166 if (mr->probability < MINSTREL_FRAC(1, 10)) {
167 mr->cur_tp = 0;
168 return;
169 }
170
171 usecs = mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
172 usecs += minstrel_mcs_groups[group].duration[rate];
173 mr->cur_tp = MINSTREL_TRUNC((1000000 / usecs) * mr->probability);
174 }
175
176 /*
177 * Update rate statistics and select new primary rates
178 *
179 * Rules for rate selection:
180 * - max_prob_rate must use only one stream, as a tradeoff between delivery
181 * probability and throughput during strong fluctuations
182 * - as long as the max prob rate has a probability of more than 3/4, pick
183 * higher throughput rates, even if the probablity is a bit lower
184 */
185 static void
186 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
187 {
188 struct minstrel_mcs_group_data *mg;
189 struct minstrel_rate_stats *mr;
190 int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
191 int group, i, index;
192
193 if (mi->ampdu_packets > 0) {
194 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
195 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
196 mi->ampdu_len = 0;
197 mi->ampdu_packets = 0;
198 }
199
200 mi->sample_slow = 0;
201 mi->sample_count = 0;
202 mi->max_tp_rate = 0;
203 mi->max_tp_rate2 = 0;
204 mi->max_prob_rate = 0;
205
206 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
207 cur_prob = 0;
208 cur_prob_tp = 0;
209 cur_tp = 0;
210 cur_tp2 = 0;
211
212 mg = &mi->groups[group];
213 if (!mg->supported)
214 continue;
215
216 mg->max_tp_rate = 0;
217 mg->max_tp_rate2 = 0;
218 mg->max_prob_rate = 0;
219 mi->sample_count++;
220
221 for (i = 0; i < MCS_GROUP_RATES; i++) {
222 if (!(mg->supported & BIT(i)))
223 continue;
224
225 mr = &mg->rates[i];
226 mr->retry_updated = false;
227 index = MCS_GROUP_RATES * group + i;
228 minstrel_calc_rate_ewma(mr);
229 minstrel_ht_calc_tp(mi, group, i);
230
231 if (!mr->cur_tp)
232 continue;
233
234 /* ignore the lowest rate of each single-stream group */
235 if (!i && minstrel_mcs_groups[group].streams == 1)
236 continue;
237
238 if ((mr->cur_tp > cur_prob_tp && mr->probability >
239 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
240 mg->max_prob_rate = index;
241 cur_prob = mr->probability;
242 cur_prob_tp = mr->cur_tp;
243 }
244
245 if (mr->cur_tp > cur_tp) {
246 swap(index, mg->max_tp_rate);
247 cur_tp = mr->cur_tp;
248 mr = minstrel_get_ratestats(mi, index);
249 }
250
251 if (index >= mg->max_tp_rate)
252 continue;
253
254 if (mr->cur_tp > cur_tp2) {
255 mg->max_tp_rate2 = index;
256 cur_tp2 = mr->cur_tp;
257 }
258 }
259 }
260
261 /* try to sample up to half of the available rates during each interval */
262 mi->sample_count *= 4;
263
264 cur_prob = 0;
265 cur_prob_tp = 0;
266 cur_tp = 0;
267 cur_tp2 = 0;
268 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
269 mg = &mi->groups[group];
270 if (!mg->supported)
271 continue;
272
273 mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
274 if (cur_prob_tp < mr->cur_tp &&
275 minstrel_mcs_groups[group].streams == 1) {
276 mi->max_prob_rate = mg->max_prob_rate;
277 cur_prob = mr->cur_prob;
278 cur_prob_tp = mr->cur_tp;
279 }
280
281 mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
282 if (cur_tp < mr->cur_tp) {
283 mi->max_tp_rate2 = mi->max_tp_rate;
284 cur_tp2 = cur_tp;
285 mi->max_tp_rate = mg->max_tp_rate;
286 cur_tp = mr->cur_tp;
287 }
288
289 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
290 if (cur_tp2 < mr->cur_tp) {
291 mi->max_tp_rate2 = mg->max_tp_rate2;
292 cur_tp2 = mr->cur_tp;
293 }
294 }
295
296 mi->stats_update = jiffies;
297 }
298
299 static bool
300 minstrel_ht_txstat_valid(struct ieee80211_tx_rate *rate)
301 {
302 if (rate->idx < 0)
303 return false;
304
305 if (!rate->count)
306 return false;
307
308 return !!(rate->flags & IEEE80211_TX_RC_MCS);
309 }
310
311 static void
312 minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
313 {
314 struct minstrel_mcs_group_data *mg;
315
316 for (;;) {
317 mi->sample_group++;
318 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
319 mg = &mi->groups[mi->sample_group];
320
321 if (!mg->supported)
322 continue;
323
324 if (++mg->index >= MCS_GROUP_RATES) {
325 mg->index = 0;
326 if (++mg->column >= ARRAY_SIZE(sample_table))
327 mg->column = 0;
328 }
329 break;
330 }
331 }
332
333 static void
334 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx,
335 bool primary)
336 {
337 int group, orig_group;
338
339 orig_group = group = *idx / MCS_GROUP_RATES;
340 while (group > 0) {
341 group--;
342
343 if (!mi->groups[group].supported)
344 continue;
345
346 if (minstrel_mcs_groups[group].streams >
347 minstrel_mcs_groups[orig_group].streams)
348 continue;
349
350 if (primary)
351 *idx = mi->groups[group].max_tp_rate;
352 else
353 *idx = mi->groups[group].max_tp_rate2;
354 break;
355 }
356 }
357
358 static void
359 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
360 {
361 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
362 struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
363 u16 tid;
364
365 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
366 return;
367
368 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
369 return;
370
371 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
372 if (likely(sta->ampdu_mlme.tid_tx[tid]))
373 return;
374
375 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
376 return;
377
378 ieee80211_start_tx_ba_session(pubsta, tid, 5000);
379 }
380
381 static void
382 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
383 struct ieee80211_sta *sta, void *priv_sta,
384 struct sk_buff *skb)
385 {
386 struct minstrel_ht_sta_priv *msp = priv_sta;
387 struct minstrel_ht_sta *mi = &msp->ht;
388 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
389 struct ieee80211_tx_rate *ar = info->status.rates;
390 struct minstrel_rate_stats *rate, *rate2;
391 struct minstrel_priv *mp = priv;
392 bool last = false;
393 int group;
394 int i = 0;
395
396 if (!msp->is_ht)
397 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
398
399 /* This packet was aggregated but doesn't carry status info */
400 if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
401 !(info->flags & IEEE80211_TX_STAT_AMPDU))
402 return;
403
404 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
405 info->status.ampdu_ack_len =
406 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
407 info->status.ampdu_len = 1;
408 }
409
410 mi->ampdu_packets++;
411 mi->ampdu_len += info->status.ampdu_len;
412
413 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
414 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
415 mi->sample_tries = 2;
416 mi->sample_count--;
417 }
418
419 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
420 mi->sample_packets += info->status.ampdu_len;
421
422 for (i = 0; !last; i++) {
423 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
424 !minstrel_ht_txstat_valid(&ar[i + 1]);
425
426 if (!minstrel_ht_txstat_valid(&ar[i]))
427 break;
428
429 group = minstrel_ht_get_group_idx(&ar[i]);
430 rate = &mi->groups[group].rates[ar[i].idx % 8];
431
432 if (last)
433 rate->success += info->status.ampdu_ack_len;
434
435 rate->attempts += ar[i].count * info->status.ampdu_len;
436 }
437
438 /*
439 * check for sudden death of spatial multiplexing,
440 * downgrade to a lower number of streams if necessary.
441 */
442 rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
443 if (rate->attempts > 30 &&
444 MINSTREL_FRAC(rate->success, rate->attempts) <
445 MINSTREL_FRAC(20, 100))
446 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
447
448 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
449 if (rate2->attempts > 30 &&
450 MINSTREL_FRAC(rate2->success, rate2->attempts) <
451 MINSTREL_FRAC(20, 100))
452 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
453
454 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
455 minstrel_ht_update_stats(mp, mi);
456 if (!(info->flags & IEEE80211_TX_CTL_AMPDU))
457 minstrel_aggr_check(sta, skb);
458 }
459 }
460
461 static void
462 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
463 int index)
464 {
465 struct minstrel_rate_stats *mr;
466 const struct mcs_group *group;
467 unsigned int tx_time, tx_time_rtscts, tx_time_data;
468 unsigned int cw = mp->cw_min;
469 unsigned int ctime = 0;
470 unsigned int t_slot = 9; /* FIXME */
471 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
472
473 mr = minstrel_get_ratestats(mi, index);
474 if (mr->probability < MINSTREL_FRAC(1, 10)) {
475 mr->retry_count = 1;
476 mr->retry_count_rtscts = 1;
477 return;
478 }
479
480 mr->retry_count = 2;
481 mr->retry_count_rtscts = 2;
482 mr->retry_updated = true;
483
484 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
485 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len;
486
487 /* Contention time for first 2 tries */
488 ctime = (t_slot * cw) >> 1;
489 cw = min((cw << 1) | 1, mp->cw_max);
490 ctime += (t_slot * cw) >> 1;
491 cw = min((cw << 1) | 1, mp->cw_max);
492
493 /* Total TX time for data and Contention after first 2 tries */
494 tx_time = ctime + 2 * (mi->overhead + tx_time_data);
495 tx_time_rtscts = ctime + 2 * (mi->overhead_rtscts + tx_time_data);
496
497 /* See how many more tries we can fit inside segment size */
498 do {
499 /* Contention time for this try */
500 ctime = (t_slot * cw) >> 1;
501 cw = min((cw << 1) | 1, mp->cw_max);
502
503 /* Total TX time after this try */
504 tx_time += ctime + mi->overhead + tx_time_data;
505 tx_time_rtscts += ctime + mi->overhead_rtscts + tx_time_data;
506
507 if (tx_time_rtscts < mp->segment_size)
508 mr->retry_count_rtscts++;
509 } while ((tx_time < mp->segment_size) &&
510 (++mr->retry_count < mp->max_retry));
511 }
512
513
514 static void
515 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
516 struct ieee80211_tx_rate *rate, int index,
517 bool sample, bool rtscts)
518 {
519 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
520 struct minstrel_rate_stats *mr;
521
522 mr = minstrel_get_ratestats(mi, index);
523 if (!mr->retry_updated)
524 minstrel_calc_retransmit(mp, mi, index);
525
526 if (sample)
527 rate->count = 1;
528 else if (mr->probability < MINSTREL_FRAC(20, 100))
529 rate->count = 2;
530 else if (rtscts)
531 rate->count = mr->retry_count_rtscts;
532 else
533 rate->count = mr->retry_count;
534
535 rate->flags = IEEE80211_TX_RC_MCS | group->flags;
536 if (rtscts)
537 rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS;
538 rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES;
539 }
540
541 static inline int
542 minstrel_get_duration(int index)
543 {
544 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
545 return group->duration[index % MCS_GROUP_RATES];
546 }
547
548 static int
549 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
550 {
551 struct minstrel_rate_stats *mr;
552 struct minstrel_mcs_group_data *mg;
553 int sample_idx = 0;
554
555 if (mi->sample_wait > 0) {
556 mi->sample_wait--;
557 return -1;
558 }
559
560 if (!mi->sample_tries)
561 return -1;
562
563 mi->sample_tries--;
564 mg = &mi->groups[mi->sample_group];
565 sample_idx = sample_table[mg->column][mg->index];
566 mr = &mg->rates[sample_idx];
567 sample_idx += mi->sample_group * MCS_GROUP_RATES;
568 minstrel_next_sample_idx(mi);
569
570 /*
571 * Sampling might add some overhead (RTS, no aggregation)
572 * to the frame. Hence, don't use sampling for the currently
573 * used max TP rate.
574 */
575 if (sample_idx == mi->max_tp_rate)
576 return -1;
577 /*
578 * When not using MRR, do not sample if the probability is already
579 * higher than 95% to avoid wasting airtime
580 */
581 if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100)))
582 return -1;
583
584 /*
585 * Make sure that lower rates get sampled only occasionally,
586 * if the link is working perfectly.
587 */
588 if (minstrel_get_duration(sample_idx) >
589 minstrel_get_duration(mi->max_tp_rate)) {
590 if (mr->sample_skipped < 20)
591 return -1;
592
593 if (mi->sample_slow++ > 2)
594 return -1;
595 }
596
597 return sample_idx;
598 }
599
600 static void
601 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
602 struct ieee80211_tx_rate_control *txrc)
603 {
604 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
605 struct ieee80211_tx_rate *ar = info->status.rates;
606 struct minstrel_ht_sta_priv *msp = priv_sta;
607 struct minstrel_ht_sta *mi = &msp->ht;
608 struct minstrel_priv *mp = priv;
609 int sample_idx;
610 bool sample = false;
611
612 if (rate_control_send_low(sta, priv_sta, txrc))
613 return;
614
615 if (!msp->is_ht)
616 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
617
618 info->flags |= mi->tx_flags;
619
620 /* Don't use EAPOL frames for sampling on non-mrr hw */
621 if (mp->hw->max_rates == 1 &&
622 txrc->skb->protocol == cpu_to_be16(ETH_P_PAE))
623 sample_idx = -1;
624 else
625 sample_idx = minstrel_get_sample_rate(mp, mi);
626
627 #ifdef CONFIG_MAC80211_DEBUGFS
628 /* use fixed index if set */
629 if (mp->fixed_rate_idx != -1)
630 sample_idx = mp->fixed_rate_idx;
631 #endif
632
633 if (sample_idx >= 0) {
634 sample = true;
635 minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
636 true, false);
637 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
638 } else {
639 minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
640 false, false);
641 }
642
643 if (mp->hw->max_rates >= 3) {
644 /*
645 * At least 3 tx rates supported, use
646 * sample_rate -> max_tp_rate -> max_prob_rate for sampling and
647 * max_tp_rate -> max_tp_rate2 -> max_prob_rate by default.
648 */
649 if (sample_idx >= 0)
650 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
651 false, false);
652 else
653 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2,
654 false, true);
655
656 minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate,
657 false, !sample);
658
659 ar[3].count = 0;
660 ar[3].idx = -1;
661 } else if (mp->hw->max_rates == 2) {
662 /*
663 * Only 2 tx rates supported, use
664 * sample_rate -> max_prob_rate for sampling and
665 * max_tp_rate -> max_prob_rate by default.
666 */
667 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_prob_rate,
668 false, !sample);
669
670 ar[2].count = 0;
671 ar[2].idx = -1;
672 } else {
673 /* Not using MRR, only use the first rate */
674 ar[1].count = 0;
675 ar[1].idx = -1;
676 }
677
678 mi->total_packets++;
679
680 /* wraparound */
681 if (mi->total_packets == ~0) {
682 mi->total_packets = 0;
683 mi->sample_packets = 0;
684 }
685 }
686
687 static void
688 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
689 struct ieee80211_sta *sta, void *priv_sta,
690 enum nl80211_channel_type oper_chan_type)
691 {
692 struct minstrel_priv *mp = priv;
693 struct minstrel_ht_sta_priv *msp = priv_sta;
694 struct minstrel_ht_sta *mi = &msp->ht;
695 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
696 struct ieee80211_local *local = hw_to_local(mp->hw);
697 u16 sta_cap = sta->ht_cap.cap;
698 int n_supported = 0;
699 int ack_dur;
700 int stbc;
701 int i;
702 unsigned int smps;
703
704 /* fall back to the old minstrel for legacy stations */
705 if (!sta->ht_cap.ht_supported)
706 goto use_legacy;
707
708 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
709 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS);
710
711 msp->is_ht = true;
712 memset(mi, 0, sizeof(*mi));
713 mi->stats_update = jiffies;
714
715 ack_dur = ieee80211_frame_duration(local, 10, 60, 1, 1);
716 mi->overhead = ieee80211_frame_duration(local, 0, 60, 1, 1) + ack_dur;
717 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
718
719 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
720
721 /* When using MRR, sample more on the first attempt, without delay */
722 if (mp->has_mrr) {
723 mi->sample_count = 16;
724 mi->sample_wait = 0;
725 } else {
726 mi->sample_count = 8;
727 mi->sample_wait = 8;
728 }
729 mi->sample_tries = 4;
730
731 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
732 IEEE80211_HT_CAP_RX_STBC_SHIFT;
733 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
734
735 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
736 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
737
738 if (oper_chan_type != NL80211_CHAN_HT40MINUS &&
739 oper_chan_type != NL80211_CHAN_HT40PLUS)
740 sta_cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
741
742 smps = (sta_cap & IEEE80211_HT_CAP_SM_PS) >>
743 IEEE80211_HT_CAP_SM_PS_SHIFT;
744
745 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
746 u16 req = 0;
747
748 mi->groups[i].supported = 0;
749 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
750 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
751 req |= IEEE80211_HT_CAP_SGI_40;
752 else
753 req |= IEEE80211_HT_CAP_SGI_20;
754 }
755
756 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
757 req |= IEEE80211_HT_CAP_SUP_WIDTH_20_40;
758
759 if ((sta_cap & req) != req)
760 continue;
761
762 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
763 if (smps == WLAN_HT_CAP_SM_PS_STATIC &&
764 minstrel_mcs_groups[i].streams > 1)
765 continue;
766
767 mi->groups[i].supported =
768 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
769
770 if (mi->groups[i].supported)
771 n_supported++;
772 }
773
774 if (!n_supported)
775 goto use_legacy;
776
777 return;
778
779 use_legacy:
780 msp->is_ht = false;
781 memset(&msp->legacy, 0, sizeof(msp->legacy));
782 msp->legacy.r = msp->ratelist;
783 msp->legacy.sample_table = msp->sample_table;
784 return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy);
785 }
786
787 static void
788 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
789 struct ieee80211_sta *sta, void *priv_sta)
790 {
791 struct minstrel_priv *mp = priv;
792
793 minstrel_ht_update_caps(priv, sband, sta, priv_sta, mp->hw->conf.channel_type);
794 }
795
796 static void
797 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
798 struct ieee80211_sta *sta, void *priv_sta,
799 u32 changed, enum nl80211_channel_type oper_chan_type)
800 {
801 minstrel_ht_update_caps(priv, sband, sta, priv_sta, oper_chan_type);
802 }
803
804 static void *
805 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
806 {
807 struct ieee80211_supported_band *sband;
808 struct minstrel_ht_sta_priv *msp;
809 struct minstrel_priv *mp = priv;
810 struct ieee80211_hw *hw = mp->hw;
811 int max_rates = 0;
812 int i;
813
814 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
815 sband = hw->wiphy->bands[i];
816 if (sband && sband->n_bitrates > max_rates)
817 max_rates = sband->n_bitrates;
818 }
819
820 msp = kzalloc(sizeof(struct minstrel_ht_sta), gfp);
821 if (!msp)
822 return NULL;
823
824 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
825 if (!msp->ratelist)
826 goto error;
827
828 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
829 if (!msp->sample_table)
830 goto error1;
831
832 return msp;
833
834 error1:
835 kfree(msp->ratelist);
836 error:
837 kfree(msp);
838 return NULL;
839 }
840
841 static void
842 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
843 {
844 struct minstrel_ht_sta_priv *msp = priv_sta;
845
846 kfree(msp->sample_table);
847 kfree(msp->ratelist);
848 kfree(msp);
849 }
850
851 static void *
852 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
853 {
854 return mac80211_minstrel.alloc(hw, debugfsdir);
855 }
856
857 static void
858 minstrel_ht_free(void *priv)
859 {
860 mac80211_minstrel.free(priv);
861 }
862
863 static struct rate_control_ops mac80211_minstrel_ht = {
864 .name = "minstrel_ht",
865 .tx_status = minstrel_ht_tx_status,
866 .get_rate = minstrel_ht_get_rate,
867 .rate_init = minstrel_ht_rate_init,
868 .rate_update = minstrel_ht_rate_update,
869 .alloc_sta = minstrel_ht_alloc_sta,
870 .free_sta = minstrel_ht_free_sta,
871 .alloc = minstrel_ht_alloc,
872 .free = minstrel_ht_free,
873 #ifdef CONFIG_MAC80211_DEBUGFS
874 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
875 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
876 #endif
877 };
878
879
880 static void
881 init_sample_table(void)
882 {
883 int col, i, new_idx;
884 u8 rnd[MCS_GROUP_RATES];
885
886 memset(sample_table, 0xff, sizeof(sample_table));
887 for (col = 0; col < SAMPLE_COLUMNS; col++) {
888 for (i = 0; i < MCS_GROUP_RATES; i++) {
889 get_random_bytes(rnd, sizeof(rnd));
890 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
891
892 while (sample_table[col][new_idx] != 0xff)
893 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
894
895 sample_table[col][new_idx] = i;
896 }
897 }
898 }
899
900 int __init
901 rc80211_minstrel_ht_init(void)
902 {
903 init_sample_table();
904 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
905 }
906
907 void
908 rc80211_minstrel_ht_exit(void)
909 {
910 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
911 }
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