2 * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>
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.
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>
16 #include "rc80211_minstrel.h"
17 #include "rc80211_minstrel_ht.h"
19 #define AVG_PKT_SIZE 1200
21 /* Number of bits for an average sized packet */
22 #define MCS_NBITS (AVG_PKT_SIZE << 3)
24 /* Number of symbols for a packet with (bps) bits per symbol */
25 #define MCS_NSYMS(bps) DIV_ROUND_UP(MCS_NBITS, (bps))
27 /* Transmission time (nanoseconds) for a packet containing (syms) symbols */
28 #define MCS_SYMBOL_TIME(sgi, syms) \
30 ((syms) * 18000 + 4000) / 5 : /* syms * 3.6 us */ \
31 ((syms) * 1000) << 2 /* syms * 4 us */ \
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)))
38 * Define group sort order: HT40 -> SGI -> #streams
40 #define GROUP_IDX(_streams, _sgi, _ht40) \
41 MINSTREL_MAX_STREAMS * 2 * _ht40 + \
42 MINSTREL_MAX_STREAMS * _sgi + \
45 /* MCS rate information for an MCS group */
46 #define MCS_GROUP(_streams, _sgi, _ht40) \
47 [GROUP_IDX(_streams, _sgi, _ht40)] = { \
48 .streams = _streams, \
50 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
51 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
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) \
64 #define CCK_DURATION(_bitrate, _short, _len) \
65 (1000 * (10 /* SIFS */ + \
66 (_short ? 72 + 24 : 144 + 48) + \
67 (8 * (_len + 4) * 10) / (_bitrate)))
69 #define CCK_ACK_DURATION(_bitrate, _short) \
70 (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) + \
71 CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))
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)
80 [MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS] = { \
83 CCK_DURATION_LIST(false), \
84 CCK_DURATION_LIST(true) \
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
93 * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
94 * HT40 -> SGI -> #streams
96 const struct mcs_group minstrel_mcs_groups[] = {
99 #if MINSTREL_MAX_STREAMS >= 3
105 #if MINSTREL_MAX_STREAMS >= 3
111 #if MINSTREL_MAX_STREAMS >= 3
117 #if MINSTREL_MAX_STREAMS >= 3
125 #define MINSTREL_CCK_GROUP (ARRAY_SIZE(minstrel_mcs_groups) - 1)
127 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
130 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
133 * Look up an MCS group index based on mac80211 rate information
136 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
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));
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)
149 if (rate->flags & IEEE80211_TX_RC_MCS) {
150 group = minstrel_ht_get_group_idx(rate);
153 group = MINSTREL_CCK_GROUP;
155 for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++)
156 if (rate->idx == mp->cck_rates[idx])
160 if (!(mi->groups[group].supported & BIT(idx)))
163 return &mi->groups[group].rates[idx];
166 static inline struct minstrel_rate_stats *
167 minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
169 return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
174 * Recalculate success probabilities and counters for a rate using EWMA
177 minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr)
179 if (unlikely(mr->attempts > 0)) {
180 mr->sample_skipped = 0;
181 mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
183 mr->probability = mr->cur_prob;
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;
190 mr->sample_skipped++;
192 mr->last_success = mr->success;
193 mr->last_attempts = mr->attempts;
199 * Calculate throughput based on the average A-MPDU length, taking into account
200 * the expected number of retransmissions and their expected length
203 minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
205 struct minstrel_rate_stats *mr;
206 unsigned int nsecs = 0;
210 mr = &mi->groups[group].rates[rate];
211 prob = mr->probability;
213 if (prob < MINSTREL_FRAC(1, 10)) {
219 * For the throughput calculation, limit the probability value to 90% to
220 * account for collision related packet error rate fluctuation
222 if (prob > MINSTREL_FRAC(9, 10))
223 prob = MINSTREL_FRAC(9, 10);
225 if (group != MINSTREL_CCK_GROUP)
226 nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
228 nsecs += minstrel_mcs_groups[group].duration[rate];
230 /* prob is scaled - see MINSTREL_FRAC above */
231 tp = 1000000 * ((prob * 1000) / nsecs);
232 mr->cur_tp = MINSTREL_TRUNC(tp);
236 * Find & sort topmost throughput rates
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.
243 minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u8 index,
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;
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;
255 tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
256 tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
257 tmp_thr = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
258 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability;
260 while (j > 0 && (cur_thr > tmp_thr ||
261 (cur_thr == tmp_thr && cur_prob > tmp_prob))) {
263 tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
264 tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
265 tmp_thr = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
266 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability;
269 if (j < MAX_THR_RATES - 1) {
270 memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) *
271 (MAX_THR_RATES - (j + 1))));
273 if (j < MAX_THR_RATES)
278 * Find and set the topmost probability rate per sta and per group
281 minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u8 index)
283 struct minstrel_mcs_group_data *mg;
284 struct minstrel_rate_stats *mr;
285 int tmp_group, tmp_idx, tmp_tp, tmp_prob, max_tp_group;
287 mg = &mi->groups[index / MCS_GROUP_RATES];
288 mr = &mg->rates[index % MCS_GROUP_RATES];
290 tmp_group = mi->max_prob_rate / MCS_GROUP_RATES;
291 tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES;
292 tmp_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
293 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability;
295 /* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
296 * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
297 max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES;
298 if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) &&
299 (max_tp_group != MINSTREL_CCK_GROUP))
302 if (mr->probability > MINSTREL_FRAC(75, 100)) {
303 if (mr->cur_tp > tmp_tp)
304 mi->max_prob_rate = index;
305 if (mr->cur_tp > mg->rates[mg->max_group_prob_rate].cur_tp)
306 mg->max_group_prob_rate = index;
308 if (mr->probability > tmp_prob)
309 mi->max_prob_rate = index;
310 if (mr->probability > mg->rates[mg->max_group_prob_rate].probability)
311 mg->max_group_prob_rate = index;
317 * Assign new rate set per sta and use CCK rates only if the fastest
318 * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted
319 * rate sets where MCS and CCK rates are mixed, because CCK rates can
320 * not use aggregation.
323 minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi,
324 u8 tmp_mcs_tp_rate[MAX_THR_RATES],
325 u8 tmp_cck_tp_rate[MAX_THR_RATES])
327 unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp;
330 tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES;
331 tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES;
332 tmp_cck_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
334 tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES;
335 tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES;
336 tmp_mcs_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
338 if (tmp_cck_tp > tmp_mcs_tp) {
339 for(i = 0; i < MAX_THR_RATES; i++) {
340 minstrel_ht_sort_best_tp_rates(mi, tmp_cck_tp_rate[i],
348 * Try to increase robustness of max_prob rate by decrease number of
349 * streams if possible.
352 minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
354 struct minstrel_mcs_group_data *mg;
355 struct minstrel_rate_stats *mr;
356 int tmp_max_streams, group;
359 tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
360 MCS_GROUP_RATES].streams;
361 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
362 mg = &mi->groups[group];
363 if (!mg->supported || group == MINSTREL_CCK_GROUP)
365 mr = minstrel_get_ratestats(mi, mg->max_group_prob_rate);
366 if (tmp_tp < mr->cur_tp &&
367 (minstrel_mcs_groups[group].streams < tmp_max_streams)) {
368 mi->max_prob_rate = mg->max_group_prob_rate;
375 * Update rate statistics and select new primary rates
377 * Rules for rate selection:
378 * - max_prob_rate must use only one stream, as a tradeoff between delivery
379 * probability and throughput during strong fluctuations
380 * - as long as the max prob rate has a probability of more than 75%, pick
381 * higher throughput rates, even if the probablity is a bit lower
384 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
386 struct minstrel_mcs_group_data *mg;
387 struct minstrel_rate_stats *mr;
389 u8 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
390 u8 tmp_cck_tp_rate[MAX_THR_RATES], index;
392 if (mi->ampdu_packets > 0) {
393 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
394 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
396 mi->ampdu_packets = 0;
400 mi->sample_count = 0;
402 /* Initialize global rate indexes */
403 for(j = 0; j < MAX_THR_RATES; j++){
404 tmp_mcs_tp_rate[j] = 0;
405 tmp_cck_tp_rate[j] = 0;
408 /* Find best rate sets within all MCS groups*/
409 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
411 mg = &mi->groups[group];
417 /* (re)Initialize group rate indexes */
418 for(j = 0; j < MAX_THR_RATES; j++)
419 tmp_group_tp_rate[j] = group;
421 for (i = 0; i < MCS_GROUP_RATES; i++) {
422 if (!(mg->supported & BIT(i)))
425 index = MCS_GROUP_RATES * group + i;
428 mr->retry_updated = false;
429 minstrel_calc_rate_ewma(mr);
430 minstrel_ht_calc_tp(mi, group, i);
435 /* Find max throughput rate set */
436 if (group != MINSTREL_CCK_GROUP) {
437 minstrel_ht_sort_best_tp_rates(mi, index,
439 } else if (group == MINSTREL_CCK_GROUP) {
440 minstrel_ht_sort_best_tp_rates(mi, index,
444 /* Find max throughput rate set within a group */
445 minstrel_ht_sort_best_tp_rates(mi, index,
448 /* Find max probability rate per group and global */
449 minstrel_ht_set_best_prob_rate(mi, index);
452 memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
453 sizeof(mg->max_group_tp_rate));
456 /* Assign new rate set per sta */
457 minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate);
458 memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));
460 /* Try to increase robustness of max_prob_rate*/
461 minstrel_ht_prob_rate_reduce_streams(mi);
463 /* try to sample all available rates during each interval */
464 mi->sample_count *= 8;
466 #ifdef CONFIG_MAC80211_DEBUGFS
467 /* use fixed index if set */
468 if (mp->fixed_rate_idx != -1) {
469 for (i = 0; i < 4; i++)
470 mi->max_tp_rate[i] = mp->fixed_rate_idx;
471 mi->max_prob_rate = mp->fixed_rate_idx;
475 /* Reset update timer */
476 mi->stats_update = jiffies;
480 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
488 if (rate->flags & IEEE80211_TX_RC_MCS)
491 return rate->idx == mp->cck_rates[0] ||
492 rate->idx == mp->cck_rates[1] ||
493 rate->idx == mp->cck_rates[2] ||
494 rate->idx == mp->cck_rates[3];
498 minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
500 struct minstrel_mcs_group_data *mg;
504 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
505 mg = &mi->groups[mi->sample_group];
510 if (++mg->index >= MCS_GROUP_RATES) {
512 if (++mg->column >= ARRAY_SIZE(sample_table))
520 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u8 *idx, bool primary)
522 int group, orig_group;
524 orig_group = group = *idx / MCS_GROUP_RATES;
528 if (!mi->groups[group].supported)
531 if (minstrel_mcs_groups[group].streams >
532 minstrel_mcs_groups[orig_group].streams)
536 *idx = mi->groups[group].max_group_tp_rate[0];
538 *idx = mi->groups[group].max_group_tp_rate[1];
544 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
546 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
547 struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
550 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
553 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
556 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
557 if (likely(sta->ampdu_mlme.tid_tx[tid]))
560 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
563 ieee80211_start_tx_ba_session(pubsta, tid, 5000);
567 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
568 struct ieee80211_sta *sta, void *priv_sta,
571 struct minstrel_ht_sta_priv *msp = priv_sta;
572 struct minstrel_ht_sta *mi = &msp->ht;
573 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
574 struct ieee80211_tx_rate *ar = info->status.rates;
575 struct minstrel_rate_stats *rate, *rate2;
576 struct minstrel_priv *mp = priv;
577 bool last, update = false;
581 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
583 /* This packet was aggregated but doesn't carry status info */
584 if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
585 !(info->flags & IEEE80211_TX_STAT_AMPDU))
588 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
589 info->status.ampdu_ack_len =
590 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
591 info->status.ampdu_len = 1;
595 mi->ampdu_len += info->status.ampdu_len;
597 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
598 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
599 mi->sample_tries = 1;
603 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
604 mi->sample_packets += info->status.ampdu_len;
606 last = !minstrel_ht_txstat_valid(mp, &ar[0]);
607 for (i = 0; !last; i++) {
608 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
609 !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
611 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
614 rate->success += info->status.ampdu_ack_len;
616 rate->attempts += ar[i].count * info->status.ampdu_len;
620 * check for sudden death of spatial multiplexing,
621 * downgrade to a lower number of streams if necessary.
623 rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
624 if (rate->attempts > 30 &&
625 MINSTREL_FRAC(rate->success, rate->attempts) <
626 MINSTREL_FRAC(20, 100)) {
627 minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
631 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
632 if (rate2->attempts > 30 &&
633 MINSTREL_FRAC(rate2->success, rate2->attempts) <
634 MINSTREL_FRAC(20, 100)) {
635 minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
639 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
641 minstrel_ht_update_stats(mp, mi);
642 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
643 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
644 minstrel_aggr_check(sta, skb);
648 minstrel_ht_update_rates(mp, mi);
652 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
655 struct minstrel_rate_stats *mr;
656 const struct mcs_group *group;
657 unsigned int tx_time, tx_time_rtscts, tx_time_data;
658 unsigned int cw = mp->cw_min;
659 unsigned int ctime = 0;
660 unsigned int t_slot = 9; /* FIXME */
661 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
662 unsigned int overhead = 0, overhead_rtscts = 0;
664 mr = minstrel_get_ratestats(mi, index);
665 if (mr->probability < MINSTREL_FRAC(1, 10)) {
667 mr->retry_count_rtscts = 1;
672 mr->retry_count_rtscts = 2;
673 mr->retry_updated = true;
675 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
676 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
678 /* Contention time for first 2 tries */
679 ctime = (t_slot * cw) >> 1;
680 cw = min((cw << 1) | 1, mp->cw_max);
681 ctime += (t_slot * cw) >> 1;
682 cw = min((cw << 1) | 1, mp->cw_max);
684 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
685 overhead = mi->overhead;
686 overhead_rtscts = mi->overhead_rtscts;
689 /* Total TX time for data and Contention after first 2 tries */
690 tx_time = ctime + 2 * (overhead + tx_time_data);
691 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
693 /* See how many more tries we can fit inside segment size */
695 /* Contention time for this try */
696 ctime = (t_slot * cw) >> 1;
697 cw = min((cw << 1) | 1, mp->cw_max);
699 /* Total TX time after this try */
700 tx_time += ctime + overhead + tx_time_data;
701 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
703 if (tx_time_rtscts < mp->segment_size)
704 mr->retry_count_rtscts++;
705 } while ((tx_time < mp->segment_size) &&
706 (++mr->retry_count < mp->max_retry));
711 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
712 struct ieee80211_sta_rates *ratetbl, int offset, int index)
714 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
715 struct minstrel_rate_stats *mr;
719 mr = minstrel_get_ratestats(mi, index);
720 if (!mr->retry_updated)
721 minstrel_calc_retransmit(mp, mi, index);
723 if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) {
724 ratetbl->rate[offset].count = 2;
725 ratetbl->rate[offset].count_rts = 2;
726 ratetbl->rate[offset].count_cts = 2;
728 ratetbl->rate[offset].count = mr->retry_count;
729 ratetbl->rate[offset].count_cts = mr->retry_count;
730 ratetbl->rate[offset].count_rts = mr->retry_count_rtscts;
733 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
734 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
737 idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;
738 flags = IEEE80211_TX_RC_MCS | group->flags;
742 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
743 flags |= IEEE80211_TX_RC_USE_RTS_CTS;
746 ratetbl->rate[offset].idx = idx;
747 ratetbl->rate[offset].flags = flags;
751 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
753 struct ieee80211_sta_rates *rates;
756 rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
760 /* Start with max_tp_rate[0] */
761 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
763 if (mp->hw->max_rates >= 3) {
764 /* At least 3 tx rates supported, use max_tp_rate[1] next */
765 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]);
768 if (mp->hw->max_rates >= 2) {
770 * At least 2 tx rates supported, use max_prob_rate next */
771 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
774 rates->rate[i].idx = -1;
775 rate_control_set_rates(mp->hw, mi->sta, rates);
779 minstrel_get_duration(int index)
781 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
782 return group->duration[index % MCS_GROUP_RATES];
786 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
788 struct minstrel_rate_stats *mr;
789 struct minstrel_mcs_group_data *mg;
790 unsigned int sample_dur, sample_group, cur_max_tp_streams;
793 if (mi->sample_wait > 0) {
798 if (!mi->sample_tries)
801 sample_group = mi->sample_group;
802 mg = &mi->groups[sample_group];
803 sample_idx = sample_table[mg->column][mg->index];
804 minstrel_next_sample_idx(mi);
806 if (!(mg->supported & BIT(sample_idx)))
809 mr = &mg->rates[sample_idx];
810 sample_idx += sample_group * MCS_GROUP_RATES;
813 * Sampling might add some overhead (RTS, no aggregation)
814 * to the frame. Hence, don't use sampling for the currently
817 if (sample_idx == mi->max_tp_rate[0] ||
818 sample_idx == mi->max_tp_rate[1] ||
819 sample_idx == mi->max_prob_rate)
823 * Do not sample if the probability is already higher than 95%
824 * to avoid wasting airtime.
826 if (mr->probability > MINSTREL_FRAC(95, 100))
830 * Make sure that lower rates get sampled only occasionally,
831 * if the link is working perfectly.
834 cur_max_tp_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
835 MCS_GROUP_RATES].streams;
836 sample_dur = minstrel_get_duration(sample_idx);
837 if (sample_dur >= minstrel_get_duration(mi->max_tp_rate[1]) &&
838 (cur_max_tp_streams - 1 <
839 minstrel_mcs_groups[sample_group].streams ||
840 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
841 if (mr->sample_skipped < 20)
844 if (mi->sample_slow++ > 2)
853 minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp,
854 struct minstrel_ht_sta *mi, bool val)
856 u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported;
858 if (!supported || !mi->cck_supported_short)
861 if (supported & (mi->cck_supported_short << (val * 4)))
864 supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4);
865 mi->groups[MINSTREL_CCK_GROUP].supported = supported;
869 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
870 struct ieee80211_tx_rate_control *txrc)
872 const struct mcs_group *sample_group;
873 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
874 struct ieee80211_tx_rate *rate = &info->status.rates[0];
875 struct minstrel_ht_sta_priv *msp = priv_sta;
876 struct minstrel_ht_sta *mi = &msp->ht;
877 struct minstrel_priv *mp = priv;
880 if (rate_control_send_low(sta, priv_sta, txrc))
884 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
886 info->flags |= mi->tx_flags;
887 minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble);
889 #ifdef CONFIG_MAC80211_DEBUGFS
890 if (mp->fixed_rate_idx != -1)
894 /* Don't use EAPOL frames for sampling on non-mrr hw */
895 if (mp->hw->max_rates == 1 &&
896 (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
899 sample_idx = minstrel_get_sample_rate(mp, mi);
904 if (mi->total_packets == ~0) {
905 mi->total_packets = 0;
906 mi->sample_packets = 0;
912 sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
913 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
916 if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
917 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
918 rate->idx = mp->cck_rates[idx];
923 rate->idx = sample_idx % MCS_GROUP_RATES +
924 (sample_group->streams - 1) * 8;
925 rate->flags = IEEE80211_TX_RC_MCS | sample_group->flags;
929 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
930 struct ieee80211_supported_band *sband,
931 struct ieee80211_sta *sta)
935 if (sband->band != IEEE80211_BAND_2GHZ)
938 if (!(mp->hw->flags & IEEE80211_HW_SUPPORTS_HT_CCK_RATES))
941 mi->cck_supported = 0;
942 mi->cck_supported_short = 0;
943 for (i = 0; i < 4; i++) {
944 if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
947 mi->cck_supported |= BIT(i);
948 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
949 mi->cck_supported_short |= BIT(i);
952 mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported;
956 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
957 struct cfg80211_chan_def *chandef,
958 struct ieee80211_sta *sta, void *priv_sta)
960 struct minstrel_priv *mp = priv;
961 struct minstrel_ht_sta_priv *msp = priv_sta;
962 struct minstrel_ht_sta *mi = &msp->ht;
963 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
964 u16 sta_cap = sta->ht_cap.cap;
970 /* fall back to the old minstrel for legacy stations */
971 if (!sta->ht_cap.ht_supported)
974 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
975 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1);
978 memset(mi, 0, sizeof(*mi));
981 mi->stats_update = jiffies;
983 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
984 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
985 mi->overhead += ack_dur;
986 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
988 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
990 /* When using MRR, sample more on the first attempt, without delay */
992 mi->sample_count = 16;
995 mi->sample_count = 8;
998 mi->sample_tries = 4;
1000 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
1001 IEEE80211_HT_CAP_RX_STBC_SHIFT;
1002 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
1004 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
1005 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
1007 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
1008 mi->groups[i].supported = 0;
1009 if (i == MINSTREL_CCK_GROUP) {
1010 minstrel_ht_update_cck(mp, mi, sband, sta);
1014 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
1015 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
1016 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
1019 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
1024 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
1025 sta->bandwidth < IEEE80211_STA_RX_BW_40)
1028 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
1029 if (sta->smps_mode == IEEE80211_SMPS_STATIC &&
1030 minstrel_mcs_groups[i].streams > 1)
1033 mi->groups[i].supported =
1034 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
1036 if (mi->groups[i].supported)
1043 /* create an initial rate table with the lowest supported rates */
1044 minstrel_ht_update_stats(mp, mi);
1045 minstrel_ht_update_rates(mp, mi);
1051 memset(&msp->legacy, 0, sizeof(msp->legacy));
1052 msp->legacy.r = msp->ratelist;
1053 msp->legacy.sample_table = msp->sample_table;
1054 return mac80211_minstrel.rate_init(priv, sband, chandef, sta,
1059 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
1060 struct cfg80211_chan_def *chandef,
1061 struct ieee80211_sta *sta, void *priv_sta)
1063 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1067 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
1068 struct cfg80211_chan_def *chandef,
1069 struct ieee80211_sta *sta, void *priv_sta,
1072 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1076 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
1078 struct ieee80211_supported_band *sband;
1079 struct minstrel_ht_sta_priv *msp;
1080 struct minstrel_priv *mp = priv;
1081 struct ieee80211_hw *hw = mp->hw;
1085 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1086 sband = hw->wiphy->bands[i];
1087 if (sband && sband->n_bitrates > max_rates)
1088 max_rates = sband->n_bitrates;
1091 msp = kzalloc(sizeof(*msp), gfp);
1095 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
1099 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
1100 if (!msp->sample_table)
1106 kfree(msp->ratelist);
1113 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1115 struct minstrel_ht_sta_priv *msp = priv_sta;
1117 kfree(msp->sample_table);
1118 kfree(msp->ratelist);
1123 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
1125 return mac80211_minstrel.alloc(hw, debugfsdir);
1129 minstrel_ht_free(void *priv)
1131 mac80211_minstrel.free(priv);
1134 static u32 minstrel_ht_get_expected_throughput(void *priv_sta)
1136 struct minstrel_ht_sta_priv *msp = priv_sta;
1137 struct minstrel_ht_sta *mi = &msp->ht;
1141 return mac80211_minstrel.get_expected_throughput(priv_sta);
1143 i = mi->max_tp_rate[0] / MCS_GROUP_RATES;
1144 j = mi->max_tp_rate[0] % MCS_GROUP_RATES;
1146 /* convert cur_tp from pkt per second in kbps */
1147 return mi->groups[i].rates[j].cur_tp * AVG_PKT_SIZE * 8 / 1024;
1150 static const struct rate_control_ops mac80211_minstrel_ht = {
1151 .name = "minstrel_ht",
1152 .tx_status = minstrel_ht_tx_status,
1153 .get_rate = minstrel_ht_get_rate,
1154 .rate_init = minstrel_ht_rate_init,
1155 .rate_update = minstrel_ht_rate_update,
1156 .alloc_sta = minstrel_ht_alloc_sta,
1157 .free_sta = minstrel_ht_free_sta,
1158 .alloc = minstrel_ht_alloc,
1159 .free = minstrel_ht_free,
1160 #ifdef CONFIG_MAC80211_DEBUGFS
1161 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
1162 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
1164 .get_expected_throughput = minstrel_ht_get_expected_throughput,
1168 static void __init init_sample_table(void)
1170 int col, i, new_idx;
1171 u8 rnd[MCS_GROUP_RATES];
1173 memset(sample_table, 0xff, sizeof(sample_table));
1174 for (col = 0; col < SAMPLE_COLUMNS; col++) {
1175 prandom_bytes(rnd, sizeof(rnd));
1176 for (i = 0; i < MCS_GROUP_RATES; i++) {
1177 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1178 while (sample_table[col][new_idx] != 0xff)
1179 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1181 sample_table[col][new_idx] = i;
1187 rc80211_minstrel_ht_init(void)
1189 init_sample_table();
1190 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1194 rc80211_minstrel_ht_exit(void)
1196 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);