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Felix Fietkauec8aa662010-05-13 16:48:03 +02001/*
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
Helmut Schaaa5f69d942011-11-14 15:28:20 +010039/*
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
Felix Fietkauec8aa662010-05-13 16:48:03 +020047/* MCS rate information for an MCS group */
Helmut Schaaa5f69d942011-11-14 15:28:20 +010048#define MCS_GROUP(_streams, _sgi, _ht40) \
49 [GROUP_IDX(_streams, _sgi, _ht40)] = { \
Felix Fietkauec8aa662010-05-13 16:48:03 +020050 .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.
Helmut Schaaa5f69d942011-11-14 15:28:20 +010070 *
71 * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
72 * HT40 -> SGI -> #streams
Felix Fietkauec8aa662010-05-13 16:48:03 +020073 */
74const 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
100static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES];
101
102/*
103 * Perform EWMA (Exponentially Weighted Moving Average) calculation
104 */
105static int
106minstrel_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 */
114static int
115minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
116{
Helmut Schaaa5f69d942011-11-14 15:28:20 +0100117 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));
Felix Fietkauec8aa662010-05-13 16:48:03 +0200120}
121
122static inline struct minstrel_rate_stats *
123minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
124{
125 return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
126}
127
128
129/*
130 * Recalculate success probabilities and counters for a rate using EWMA
131 */
132static void
Patrick Kelle6048d7632011-11-15 16:44:48 +0100133minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr)
Felix Fietkauec8aa662010-05-13 16:48:03 +0200134{
135 if (unlikely(mr->attempts > 0)) {
136 mr->sample_skipped = 0;
137 mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
138 if (!mr->att_hist)
139 mr->probability = mr->cur_prob;
140 else
141 mr->probability = minstrel_ewma(mr->probability,
142 mr->cur_prob, EWMA_LEVEL);
143 mr->att_hist += mr->attempts;
144 mr->succ_hist += mr->success;
145 } else {
146 mr->sample_skipped++;
147 }
148 mr->last_success = mr->success;
149 mr->last_attempts = mr->attempts;
150 mr->success = 0;
151 mr->attempts = 0;
152}
153
154/*
155 * Calculate throughput based on the average A-MPDU length, taking into account
156 * the expected number of retransmissions and their expected length
157 */
158static void
Patrick Kelle6048d7632011-11-15 16:44:48 +0100159minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
Felix Fietkauec8aa662010-05-13 16:48:03 +0200160{
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 */
185static void
186minstrel_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;
Patrick Kelle6048d7632011-11-15 16:44:48 +0100228 minstrel_calc_rate_ewma(mr);
229 minstrel_ht_calc_tp(mi, group, i);
Felix Fietkauec8aa662010-05-13 16:48:03 +0200230
231 if (!mr->cur_tp)
232 continue;
233
Felix Fietkauec8aa662010-05-13 16:48:03 +0200234 if ((mr->cur_tp > cur_prob_tp && mr->probability >
235 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
236 mg->max_prob_rate = index;
237 cur_prob = mr->probability;
Ming Lei009271f2010-07-01 23:18:42 +0800238 cur_prob_tp = mr->cur_tp;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200239 }
240
241 if (mr->cur_tp > cur_tp) {
242 swap(index, mg->max_tp_rate);
243 cur_tp = mr->cur_tp;
244 mr = minstrel_get_ratestats(mi, index);
245 }
246
247 if (index >= mg->max_tp_rate)
248 continue;
249
250 if (mr->cur_tp > cur_tp2) {
251 mg->max_tp_rate2 = index;
252 cur_tp2 = mr->cur_tp;
253 }
254 }
255 }
256
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300257 /* try to sample up to half of the available rates during each interval */
Felix Fietkauec8aa662010-05-13 16:48:03 +0200258 mi->sample_count *= 4;
259
260 cur_prob = 0;
261 cur_prob_tp = 0;
262 cur_tp = 0;
263 cur_tp2 = 0;
264 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
265 mg = &mi->groups[group];
266 if (!mg->supported)
267 continue;
268
269 mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
270 if (cur_prob_tp < mr->cur_tp &&
271 minstrel_mcs_groups[group].streams == 1) {
272 mi->max_prob_rate = mg->max_prob_rate;
273 cur_prob = mr->cur_prob;
Ming Lei009271f2010-07-01 23:18:42 +0800274 cur_prob_tp = mr->cur_tp;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200275 }
276
277 mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
278 if (cur_tp < mr->cur_tp) {
Lorenzo Bianconi89888e32011-09-24 18:48:26 +0200279 mi->max_tp_rate2 = mi->max_tp_rate;
280 cur_tp2 = cur_tp;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200281 mi->max_tp_rate = mg->max_tp_rate;
282 cur_tp = mr->cur_tp;
283 }
284
285 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
286 if (cur_tp2 < mr->cur_tp) {
287 mi->max_tp_rate2 = mg->max_tp_rate2;
288 cur_tp2 = mr->cur_tp;
289 }
290 }
291
292 mi->stats_update = jiffies;
293}
294
295static bool
296minstrel_ht_txstat_valid(struct ieee80211_tx_rate *rate)
297{
Helmut Schaab79296b2011-11-14 15:28:19 +0100298 if (rate->idx < 0)
Felix Fietkauec8aa662010-05-13 16:48:03 +0200299 return false;
300
Helmut Schaab79296b2011-11-14 15:28:19 +0100301 if (!rate->count)
Felix Fietkauec8aa662010-05-13 16:48:03 +0200302 return false;
303
304 return !!(rate->flags & IEEE80211_TX_RC_MCS);
305}
306
307static void
308minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
309{
310 struct minstrel_mcs_group_data *mg;
311
312 for (;;) {
313 mi->sample_group++;
314 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
315 mg = &mi->groups[mi->sample_group];
316
317 if (!mg->supported)
318 continue;
319
320 if (++mg->index >= MCS_GROUP_RATES) {
321 mg->index = 0;
322 if (++mg->column >= ARRAY_SIZE(sample_table))
323 mg->column = 0;
324 }
325 break;
326 }
327}
328
329static void
John W. Linvilled5ece212010-06-24 11:18:38 -0400330minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx,
331 bool primary)
Felix Fietkauec8aa662010-05-13 16:48:03 +0200332{
333 int group, orig_group;
334
335 orig_group = group = *idx / MCS_GROUP_RATES;
336 while (group > 0) {
337 group--;
338
339 if (!mi->groups[group].supported)
340 continue;
341
342 if (minstrel_mcs_groups[group].streams >
343 minstrel_mcs_groups[orig_group].streams)
344 continue;
345
346 if (primary)
347 *idx = mi->groups[group].max_tp_rate;
348 else
349 *idx = mi->groups[group].max_tp_rate2;
350 break;
351 }
352}
353
354static void
Patrick Kelle6048d7632011-11-15 16:44:48 +0100355minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
Felix Fietkauec8aa662010-05-13 16:48:03 +0200356{
357 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
358 struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
359 u16 tid;
360
361 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
362 return;
363
364 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
365 return;
366
367 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
Johannes Berga622ab72010-06-10 10:21:39 +0200368 if (likely(sta->ampdu_mlme.tid_tx[tid]))
Felix Fietkauec8aa662010-05-13 16:48:03 +0200369 return;
370
Luis R. Rodriguez48124d12010-11-23 15:05:02 -0800371 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
372 return;
373
Sujith Manoharanbd2ce6e2010-12-15 07:47:10 +0530374 ieee80211_start_tx_ba_session(pubsta, tid, 5000);
Felix Fietkauec8aa662010-05-13 16:48:03 +0200375}
376
377static void
378minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
379 struct ieee80211_sta *sta, void *priv_sta,
380 struct sk_buff *skb)
381{
382 struct minstrel_ht_sta_priv *msp = priv_sta;
383 struct minstrel_ht_sta *mi = &msp->ht;
384 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
385 struct ieee80211_tx_rate *ar = info->status.rates;
386 struct minstrel_rate_stats *rate, *rate2;
387 struct minstrel_priv *mp = priv;
Johannes Berga544ab72012-11-13 21:36:27 +0100388 bool last;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200389 int group;
Johannes Berga544ab72012-11-13 21:36:27 +0100390 int i;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200391
392 if (!msp->is_ht)
393 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
394
395 /* This packet was aggregated but doesn't carry status info */
396 if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
397 !(info->flags & IEEE80211_TX_STAT_AMPDU))
398 return;
399
Björn Smedman15d46f32010-10-10 22:14:25 +0200400 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
401 info->status.ampdu_ack_len =
402 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
Felix Fietkauec8aa662010-05-13 16:48:03 +0200403 info->status.ampdu_len = 1;
404 }
405
406 mi->ampdu_packets++;
407 mi->ampdu_len += info->status.ampdu_len;
408
409 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
Felix Fietkauc7317e42010-10-21 02:47:25 +0200410 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
411 mi->sample_tries = 2;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200412 mi->sample_count--;
413 }
414
Daniel Halperin8d5eab52011-03-09 03:10:18 -0800415 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
Felix Fietkauec8aa662010-05-13 16:48:03 +0200416 mi->sample_packets += info->status.ampdu_len;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200417
Johannes Berga544ab72012-11-13 21:36:27 +0100418 last = !minstrel_ht_txstat_valid(&ar[0]);
Felix Fietkauec8aa662010-05-13 16:48:03 +0200419 for (i = 0; !last; i++) {
420 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
421 !minstrel_ht_txstat_valid(&ar[i + 1]);
422
Felix Fietkauec8aa662010-05-13 16:48:03 +0200423 group = minstrel_ht_get_group_idx(&ar[i]);
424 rate = &mi->groups[group].rates[ar[i].idx % 8];
425
Björn Smedman15d46f32010-10-10 22:14:25 +0200426 if (last)
Felix Fietkauec8aa662010-05-13 16:48:03 +0200427 rate->success += info->status.ampdu_ack_len;
428
429 rate->attempts += ar[i].count * info->status.ampdu_len;
430 }
431
432 /*
433 * check for sudden death of spatial multiplexing,
434 * downgrade to a lower number of streams if necessary.
435 */
436 rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
437 if (rate->attempts > 30 &&
438 MINSTREL_FRAC(rate->success, rate->attempts) <
439 MINSTREL_FRAC(20, 100))
440 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
441
442 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
Ming Leiecc3d5a2010-07-01 23:19:50 +0800443 if (rate2->attempts > 30 &&
444 MINSTREL_FRAC(rate2->success, rate2->attempts) <
Felix Fietkauec8aa662010-05-13 16:48:03 +0200445 MINSTREL_FRAC(20, 100))
446 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
447
448 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
449 minstrel_ht_update_stats(mp, mi);
Christian Lamparter64ed5cf2011-09-03 09:06:20 +0200450 if (!(info->flags & IEEE80211_TX_CTL_AMPDU))
Patrick Kelle6048d7632011-11-15 16:44:48 +0100451 minstrel_aggr_check(sta, skb);
Felix Fietkauec8aa662010-05-13 16:48:03 +0200452 }
453}
454
455static void
456minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
457 int index)
458{
459 struct minstrel_rate_stats *mr;
460 const struct mcs_group *group;
461 unsigned int tx_time, tx_time_rtscts, tx_time_data;
462 unsigned int cw = mp->cw_min;
Daniel Halperin8fddddf2011-05-10 19:00:45 -0700463 unsigned int ctime = 0;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200464 unsigned int t_slot = 9; /* FIXME */
465 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
466
467 mr = minstrel_get_ratestats(mi, index);
468 if (mr->probability < MINSTREL_FRAC(1, 10)) {
469 mr->retry_count = 1;
470 mr->retry_count_rtscts = 1;
471 return;
472 }
473
474 mr->retry_count = 2;
475 mr->retry_count_rtscts = 2;
476 mr->retry_updated = true;
477
478 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
479 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len;
Daniel Halperin8fddddf2011-05-10 19:00:45 -0700480
481 /* Contention time for first 2 tries */
482 ctime = (t_slot * cw) >> 1;
483 cw = min((cw << 1) | 1, mp->cw_max);
484 ctime += (t_slot * cw) >> 1;
485 cw = min((cw << 1) | 1, mp->cw_max);
486
487 /* Total TX time for data and Contention after first 2 tries */
488 tx_time = ctime + 2 * (mi->overhead + tx_time_data);
489 tx_time_rtscts = ctime + 2 * (mi->overhead_rtscts + tx_time_data);
490
491 /* See how many more tries we can fit inside segment size */
Felix Fietkauec8aa662010-05-13 16:48:03 +0200492 do {
Daniel Halperin8fddddf2011-05-10 19:00:45 -0700493 /* Contention time for this try */
494 ctime = (t_slot * cw) >> 1;
495 cw = min((cw << 1) | 1, mp->cw_max);
496
497 /* Total TX time after this try */
498 tx_time += ctime + mi->overhead + tx_time_data;
499 tx_time_rtscts += ctime + mi->overhead_rtscts + tx_time_data;
500
Felix Fietkauec8aa662010-05-13 16:48:03 +0200501 if (tx_time_rtscts < mp->segment_size)
502 mr->retry_count_rtscts++;
503 } while ((tx_time < mp->segment_size) &&
504 (++mr->retry_count < mp->max_retry));
505}
506
507
508static void
509minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
510 struct ieee80211_tx_rate *rate, int index,
Felix Fietkauec8aa662010-05-13 16:48:03 +0200511 bool sample, bool rtscts)
512{
513 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
514 struct minstrel_rate_stats *mr;
515
516 mr = minstrel_get_ratestats(mi, index);
517 if (!mr->retry_updated)
518 minstrel_calc_retransmit(mp, mi, index);
519
Felix Fietkauc7317e42010-10-21 02:47:25 +0200520 if (sample)
521 rate->count = 1;
522 else if (mr->probability < MINSTREL_FRAC(20, 100))
Felix Fietkauec8aa662010-05-13 16:48:03 +0200523 rate->count = 2;
524 else if (rtscts)
525 rate->count = mr->retry_count_rtscts;
526 else
527 rate->count = mr->retry_count;
528
529 rate->flags = IEEE80211_TX_RC_MCS | group->flags;
Helmut Schaa9d468d22011-03-04 13:31:31 +0100530 if (rtscts)
Felix Fietkauec8aa662010-05-13 16:48:03 +0200531 rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS;
532 rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES;
533}
534
535static inline int
536minstrel_get_duration(int index)
537{
538 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
539 return group->duration[index % MCS_GROUP_RATES];
540}
541
542static int
543minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
544{
545 struct minstrel_rate_stats *mr;
546 struct minstrel_mcs_group_data *mg;
547 int sample_idx = 0;
548
549 if (mi->sample_wait > 0) {
550 mi->sample_wait--;
551 return -1;
552 }
553
554 if (!mi->sample_tries)
555 return -1;
556
557 mi->sample_tries--;
558 mg = &mi->groups[mi->sample_group];
559 sample_idx = sample_table[mg->column][mg->index];
560 mr = &mg->rates[sample_idx];
561 sample_idx += mi->sample_group * MCS_GROUP_RATES;
Daniel Halperin8d5eab52011-03-09 03:10:18 -0800562 minstrel_next_sample_idx(mi);
Felix Fietkauec8aa662010-05-13 16:48:03 +0200563
564 /*
Helmut Schaaba6fa292012-03-14 13:31:11 +0100565 * Sampling might add some overhead (RTS, no aggregation)
566 * to the frame. Hence, don't use sampling for the currently
567 * used max TP rate.
568 */
569 if (sample_idx == mi->max_tp_rate)
570 return -1;
571 /*
Felix Fietkauec8aa662010-05-13 16:48:03 +0200572 * When not using MRR, do not sample if the probability is already
573 * higher than 95% to avoid wasting airtime
574 */
575 if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100)))
Daniel Halperin8d5eab52011-03-09 03:10:18 -0800576 return -1;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200577
578 /*
579 * Make sure that lower rates get sampled only occasionally,
580 * if the link is working perfectly.
581 */
582 if (minstrel_get_duration(sample_idx) >
583 minstrel_get_duration(mi->max_tp_rate)) {
Felix Fietkauc7317e42010-10-21 02:47:25 +0200584 if (mr->sample_skipped < 20)
Daniel Halperin8d5eab52011-03-09 03:10:18 -0800585 return -1;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200586
587 if (mi->sample_slow++ > 2)
Daniel Halperin8d5eab52011-03-09 03:10:18 -0800588 return -1;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200589 }
590
591 return sample_idx;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200592}
593
594static void
595minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
596 struct ieee80211_tx_rate_control *txrc)
597{
598 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
599 struct ieee80211_tx_rate *ar = info->status.rates;
600 struct minstrel_ht_sta_priv *msp = priv_sta;
601 struct minstrel_ht_sta *mi = &msp->ht;
602 struct minstrel_priv *mp = priv;
603 int sample_idx;
Felix Fietkauc7317e42010-10-21 02:47:25 +0200604 bool sample = false;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200605
606 if (rate_control_send_low(sta, priv_sta, txrc))
607 return;
608
609 if (!msp->is_ht)
610 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
611
612 info->flags |= mi->tx_flags;
Helmut Schaa6de062c2011-08-01 11:32:53 +0200613
614 /* Don't use EAPOL frames for sampling on non-mrr hw */
615 if (mp->hw->max_rates == 1 &&
616 txrc->skb->protocol == cpu_to_be16(ETH_P_PAE))
617 sample_idx = -1;
618 else
619 sample_idx = minstrel_get_sample_rate(mp, mi);
Zefir Kurtisi24f75802011-05-20 20:29:17 +0200620
621#ifdef CONFIG_MAC80211_DEBUGFS
622 /* use fixed index if set */
Sylvain Roger Rieunier2a9e6c52012-07-09 19:25:09 +0200623 if (mp->fixed_rate_idx != -1) {
624 mi->max_tp_rate = mp->fixed_rate_idx;
625 mi->max_tp_rate2 = mp->fixed_rate_idx;
626 mi->max_prob_rate = mp->fixed_rate_idx;
627 sample_idx = -1;
628 }
Zefir Kurtisi24f75802011-05-20 20:29:17 +0200629#endif
630
Felix Fietkauec8aa662010-05-13 16:48:03 +0200631 if (sample_idx >= 0) {
Felix Fietkauc7317e42010-10-21 02:47:25 +0200632 sample = true;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200633 minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
Patrick Kelle6048d7632011-11-15 16:44:48 +0100634 true, false);
Felix Fietkauec8aa662010-05-13 16:48:03 +0200635 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
636 } else {
637 minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
Patrick Kelle6048d7632011-11-15 16:44:48 +0100638 false, false);
Felix Fietkauec8aa662010-05-13 16:48:03 +0200639 }
Felix Fietkauec8aa662010-05-13 16:48:03 +0200640
Helmut Schaacf28d792011-03-09 10:02:38 +0100641 if (mp->hw->max_rates >= 3) {
642 /*
643 * At least 3 tx rates supported, use
644 * sample_rate -> max_tp_rate -> max_prob_rate for sampling and
645 * max_tp_rate -> max_tp_rate2 -> max_prob_rate by default.
646 */
647 if (sample_idx >= 0)
648 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
Patrick Kelle6048d7632011-11-15 16:44:48 +0100649 false, false);
Helmut Schaacf28d792011-03-09 10:02:38 +0100650 else
651 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2,
Patrick Kelle6048d7632011-11-15 16:44:48 +0100652 false, true);
Helmut Schaacf28d792011-03-09 10:02:38 +0100653
654 minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate,
Patrick Kelle6048d7632011-11-15 16:44:48 +0100655 false, !sample);
Helmut Schaacf28d792011-03-09 10:02:38 +0100656
657 ar[3].count = 0;
658 ar[3].idx = -1;
659 } else if (mp->hw->max_rates == 2) {
660 /*
661 * Only 2 tx rates supported, use
662 * sample_rate -> max_prob_rate for sampling and
663 * max_tp_rate -> max_prob_rate by default.
664 */
665 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_prob_rate,
Patrick Kelle6048d7632011-11-15 16:44:48 +0100666 false, !sample);
Helmut Schaacf28d792011-03-09 10:02:38 +0100667
668 ar[2].count = 0;
669 ar[2].idx = -1;
670 } else {
671 /* Not using MRR, only use the first rate */
672 ar[1].count = 0;
673 ar[1].idx = -1;
674 }
Felix Fietkauec8aa662010-05-13 16:48:03 +0200675
676 mi->total_packets++;
677
678 /* wraparound */
679 if (mi->total_packets == ~0) {
680 mi->total_packets = 0;
681 mi->sample_packets = 0;
682 }
683}
684
685static void
686minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
Johannes Berg64f68e52012-03-28 10:58:37 +0200687 struct ieee80211_sta *sta, void *priv_sta)
Felix Fietkauec8aa662010-05-13 16:48:03 +0200688{
689 struct minstrel_priv *mp = priv;
690 struct minstrel_ht_sta_priv *msp = priv_sta;
691 struct minstrel_ht_sta *mi = &msp->ht;
692 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200693 u16 sta_cap = sta->ht_cap.cap;
Felix Fietkau4dc217d2011-03-25 15:30:38 +0100694 int n_supported = 0;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200695 int ack_dur;
696 int stbc;
697 int i;
Helmut Schaae9219772012-03-09 14:13:45 +0100698 unsigned int smps;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200699
700 /* fall back to the old minstrel for legacy stations */
Felix Fietkau4dc217d2011-03-25 15:30:38 +0100701 if (!sta->ht_cap.ht_supported)
702 goto use_legacy;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200703
704 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
705 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS);
706
707 msp->is_ht = true;
708 memset(mi, 0, sizeof(*mi));
709 mi->stats_update = jiffies;
710
Michal Kazior4ee73f32012-04-11 08:47:56 +0200711 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1);
712 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1) + ack_dur;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200713 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
714
715 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
716
717 /* When using MRR, sample more on the first attempt, without delay */
718 if (mp->has_mrr) {
719 mi->sample_count = 16;
720 mi->sample_wait = 0;
721 } else {
722 mi->sample_count = 8;
723 mi->sample_wait = 8;
724 }
725 mi->sample_tries = 4;
726
727 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
728 IEEE80211_HT_CAP_RX_STBC_SHIFT;
729 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
730
731 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
732 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
733
Helmut Schaae9219772012-03-09 14:13:45 +0100734 smps = (sta_cap & IEEE80211_HT_CAP_SM_PS) >>
735 IEEE80211_HT_CAP_SM_PS_SHIFT;
736
Felix Fietkauec8aa662010-05-13 16:48:03 +0200737 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
738 u16 req = 0;
739
740 mi->groups[i].supported = 0;
741 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
742 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
743 req |= IEEE80211_HT_CAP_SGI_40;
744 else
745 req |= IEEE80211_HT_CAP_SGI_20;
746 }
747
748 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
749 req |= IEEE80211_HT_CAP_SUP_WIDTH_20_40;
750
751 if ((sta_cap & req) != req)
752 continue;
753
Helmut Schaae9219772012-03-09 14:13:45 +0100754 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
755 if (smps == WLAN_HT_CAP_SM_PS_STATIC &&
756 minstrel_mcs_groups[i].streams > 1)
757 continue;
758
Felix Fietkauec8aa662010-05-13 16:48:03 +0200759 mi->groups[i].supported =
760 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
Felix Fietkau4dc217d2011-03-25 15:30:38 +0100761
762 if (mi->groups[i].supported)
763 n_supported++;
Felix Fietkauec8aa662010-05-13 16:48:03 +0200764 }
Felix Fietkau4dc217d2011-03-25 15:30:38 +0100765
766 if (!n_supported)
767 goto use_legacy;
768
769 return;
770
771use_legacy:
772 msp->is_ht = false;
773 memset(&msp->legacy, 0, sizeof(msp->legacy));
774 msp->legacy.r = msp->ratelist;
775 msp->legacy.sample_table = msp->sample_table;
776 return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy);
Felix Fietkauec8aa662010-05-13 16:48:03 +0200777}
778
779static void
780minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
781 struct ieee80211_sta *sta, void *priv_sta)
782{
Johannes Berg64f68e52012-03-28 10:58:37 +0200783 minstrel_ht_update_caps(priv, sband, sta, priv_sta);
Felix Fietkauec8aa662010-05-13 16:48:03 +0200784}
785
786static void
787minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
788 struct ieee80211_sta *sta, void *priv_sta,
Johannes Berg64f68e52012-03-28 10:58:37 +0200789 u32 changed)
Felix Fietkauec8aa662010-05-13 16:48:03 +0200790{
Johannes Berg64f68e52012-03-28 10:58:37 +0200791 minstrel_ht_update_caps(priv, sband, sta, priv_sta);
Felix Fietkauec8aa662010-05-13 16:48:03 +0200792}
793
794static void *
795minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
796{
797 struct ieee80211_supported_band *sband;
798 struct minstrel_ht_sta_priv *msp;
799 struct minstrel_priv *mp = priv;
800 struct ieee80211_hw *hw = mp->hw;
801 int max_rates = 0;
802 int i;
803
804 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
805 sband = hw->wiphy->bands[i];
806 if (sband && sband->n_bitrates > max_rates)
807 max_rates = sband->n_bitrates;
808 }
809
Thomas Huehn472dd352012-06-29 06:26:27 -0700810 msp = kzalloc(sizeof(*msp), gfp);
Felix Fietkauec8aa662010-05-13 16:48:03 +0200811 if (!msp)
812 return NULL;
813
814 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
815 if (!msp->ratelist)
816 goto error;
817
818 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
819 if (!msp->sample_table)
820 goto error1;
821
822 return msp;
823
824error1:
Dan Carpenter7e988012010-07-22 13:14:19 +0200825 kfree(msp->ratelist);
Felix Fietkauec8aa662010-05-13 16:48:03 +0200826error:
827 kfree(msp);
828 return NULL;
829}
830
831static void
832minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
833{
834 struct minstrel_ht_sta_priv *msp = priv_sta;
835
836 kfree(msp->sample_table);
837 kfree(msp->ratelist);
838 kfree(msp);
839}
840
841static void *
842minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
843{
844 return mac80211_minstrel.alloc(hw, debugfsdir);
845}
846
847static void
848minstrel_ht_free(void *priv)
849{
850 mac80211_minstrel.free(priv);
851}
852
853static struct rate_control_ops mac80211_minstrel_ht = {
854 .name = "minstrel_ht",
855 .tx_status = minstrel_ht_tx_status,
856 .get_rate = minstrel_ht_get_rate,
857 .rate_init = minstrel_ht_rate_init,
858 .rate_update = minstrel_ht_rate_update,
859 .alloc_sta = minstrel_ht_alloc_sta,
860 .free_sta = minstrel_ht_free_sta,
861 .alloc = minstrel_ht_alloc,
862 .free = minstrel_ht_free,
863#ifdef CONFIG_MAC80211_DEBUGFS
864 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
865 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
866#endif
867};
868
869
870static void
871init_sample_table(void)
872{
873 int col, i, new_idx;
874 u8 rnd[MCS_GROUP_RATES];
875
876 memset(sample_table, 0xff, sizeof(sample_table));
877 for (col = 0; col < SAMPLE_COLUMNS; col++) {
878 for (i = 0; i < MCS_GROUP_RATES; i++) {
879 get_random_bytes(rnd, sizeof(rnd));
880 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
881
882 while (sample_table[col][new_idx] != 0xff)
883 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
884
885 sample_table[col][new_idx] = i;
886 }
887 }
888}
889
890int __init
891rc80211_minstrel_ht_init(void)
892{
893 init_sample_table();
894 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
895}
896
897void
898rc80211_minstrel_ht_exit(void)
899{
900 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
901}