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
20 #define SAMPLE_COLUMNS 10
22 /* Number of bits for an average sized packet */
23 #define MCS_NBITS (AVG_PKT_SIZE << 3)
25 /* Number of symbols for a packet with (bps) bits per symbol */
26 #define MCS_NSYMS(bps) ((MCS_NBITS + (bps) - 1) / (bps))
28 /* Transmission time (nanoseconds) for a packet containing (syms) symbols */
29 #define MCS_SYMBOL_TIME(sgi, syms) \
31 ((syms) * 18000 + 4000) / 5 : /* syms * 3.6 us */ \
32 ((syms) * 1000) << 2 /* syms * 4 us */ \
35 /* Transmit duration for the raw data part of an average sized packet */
36 #define MCS_DURATION(streams, sgi, bps) MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps)))
39 * Define group sort order: HT40 -> SGI -> #streams
41 #define GROUP_IDX(_streams, _sgi, _ht40) \
42 MINSTREL_MAX_STREAMS * 2 * _ht40 + \
43 MINSTREL_MAX_STREAMS * _sgi + \
46 /* MCS rate information for an MCS group */
47 #define MCS_GROUP(_streams, _sgi, _ht40) \
48 [GROUP_IDX(_streams, _sgi, _ht40)] = { \
49 .streams = _streams, \
51 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
52 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
54 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \
55 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \
56 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \
57 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \
58 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \
59 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \
60 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \
61 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \
65 #define CCK_DURATION(_bitrate, _short, _len) \
66 (1000 * (10 /* SIFS */ + \
67 (_short ? 72 + 24 : 144 + 48 ) + \
68 (8 * (_len + 4) * 10) / (_bitrate)))
70 #define CCK_ACK_DURATION(_bitrate, _short) \
71 (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) + \
72 CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))
74 #define CCK_DURATION_LIST(_short) \
75 CCK_ACK_DURATION(10, _short), \
76 CCK_ACK_DURATION(20, _short), \
77 CCK_ACK_DURATION(55, _short), \
78 CCK_ACK_DURATION(110, _short)
81 [MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS] = { \
84 CCK_DURATION_LIST(false), \
85 CCK_DURATION_LIST(true) \
90 * To enable sufficiently targeted rate sampling, MCS rates are divided into
91 * groups, based on the number of streams and flags (HT40, SGI) that they
94 * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
95 * HT40 -> SGI -> #streams
97 const struct mcs_group minstrel_mcs_groups[] = {
100 #if MINSTREL_MAX_STREAMS >= 3
106 #if MINSTREL_MAX_STREAMS >= 3
112 #if MINSTREL_MAX_STREAMS >= 3
118 #if MINSTREL_MAX_STREAMS >= 3
126 #define MINSTREL_CCK_GROUP (ARRAY_SIZE(minstrel_mcs_groups) - 1)
128 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES];
131 * Look up an MCS group index based on mac80211 rate information
134 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
136 return GROUP_IDX((rate->idx / MCS_GROUP_RATES) + 1,
137 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
138 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
141 static struct minstrel_rate_stats *
142 minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
143 struct ieee80211_tx_rate *rate)
147 if (rate->flags & IEEE80211_TX_RC_MCS) {
148 group = minstrel_ht_get_group_idx(rate);
149 idx = rate->idx % MCS_GROUP_RATES;
151 group = MINSTREL_CCK_GROUP;
153 for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++)
154 if (rate->idx == mp->cck_rates[idx])
158 if (!(mi->groups[group].supported & BIT(idx)))
161 return &mi->groups[group].rates[idx];
164 static inline struct minstrel_rate_stats *
165 minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
167 return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
172 * Recalculate success probabilities and counters for a rate using EWMA
175 minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr)
177 if (unlikely(mr->attempts > 0)) {
178 mr->sample_skipped = 0;
179 mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
181 mr->probability = mr->cur_prob;
183 mr->probability = minstrel_ewma(mr->probability,
184 mr->cur_prob, EWMA_LEVEL);
185 mr->att_hist += mr->attempts;
186 mr->succ_hist += mr->success;
188 mr->sample_skipped++;
190 mr->last_success = mr->success;
191 mr->last_attempts = mr->attempts;
197 * Calculate throughput based on the average A-MPDU length, taking into account
198 * the expected number of retransmissions and their expected length
201 minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
203 struct minstrel_rate_stats *mr;
204 unsigned int nsecs = 0;
207 mr = &mi->groups[group].rates[rate];
209 if (mr->probability < MINSTREL_FRAC(1, 10)) {
214 if (group != MINSTREL_CCK_GROUP)
215 nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
217 nsecs += minstrel_mcs_groups[group].duration[rate];
218 tp = 1000000 * ((mr->probability * 1000) / nsecs);
220 mr->cur_tp = MINSTREL_TRUNC(tp);
224 * Update rate statistics and select new primary rates
226 * Rules for rate selection:
227 * - max_prob_rate must use only one stream, as a tradeoff between delivery
228 * probability and throughput during strong fluctuations
229 * - as long as the max prob rate has a probability of more than 3/4, pick
230 * higher throughput rates, even if the probablity is a bit lower
233 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
235 struct minstrel_mcs_group_data *mg;
236 struct minstrel_rate_stats *mr;
237 int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
240 if (mi->ampdu_packets > 0) {
241 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
242 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
244 mi->ampdu_packets = 0;
248 mi->sample_count = 0;
250 mi->max_tp_rate2 = 0;
251 mi->max_prob_rate = 0;
253 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
259 mg = &mi->groups[group];
264 mg->max_tp_rate2 = 0;
265 mg->max_prob_rate = 0;
268 for (i = 0; i < MCS_GROUP_RATES; i++) {
269 if (!(mg->supported & BIT(i)))
273 mr->retry_updated = false;
274 index = MCS_GROUP_RATES * group + i;
275 minstrel_calc_rate_ewma(mr);
276 minstrel_ht_calc_tp(mi, group, i);
281 if ((mr->cur_tp > cur_prob_tp && mr->probability >
282 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
283 mg->max_prob_rate = index;
284 cur_prob = mr->probability;
285 cur_prob_tp = mr->cur_tp;
288 if (mr->cur_tp > cur_tp) {
289 swap(index, mg->max_tp_rate);
291 mr = minstrel_get_ratestats(mi, index);
294 if (index >= mg->max_tp_rate)
297 if (mr->cur_tp > cur_tp2) {
298 mg->max_tp_rate2 = index;
299 cur_tp2 = mr->cur_tp;
304 /* try to sample all available rates during each interval */
305 mi->sample_count *= 8;
311 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
312 mg = &mi->groups[group];
316 mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
317 if (cur_tp < mr->cur_tp) {
318 mi->max_tp_rate2 = mi->max_tp_rate;
320 mi->max_tp_rate = mg->max_tp_rate;
322 mi->max_prob_streams = minstrel_mcs_groups[group].streams - 1;
325 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
326 if (cur_tp2 < mr->cur_tp) {
327 mi->max_tp_rate2 = mg->max_tp_rate2;
328 cur_tp2 = mr->cur_tp;
332 if (mi->max_prob_streams < 1)
333 mi->max_prob_streams = 1;
335 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
336 mg = &mi->groups[group];
339 mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
340 if (cur_prob_tp < mr->cur_tp &&
341 minstrel_mcs_groups[group].streams <= mi->max_prob_streams) {
342 mi->max_prob_rate = mg->max_prob_rate;
343 cur_prob = mr->cur_prob;
344 cur_prob_tp = mr->cur_tp;
349 mi->stats_update = jiffies;
353 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
361 if (rate->flags & IEEE80211_TX_RC_MCS)
364 return rate->idx == mp->cck_rates[0] ||
365 rate->idx == mp->cck_rates[1] ||
366 rate->idx == mp->cck_rates[2] ||
367 rate->idx == mp->cck_rates[3];
371 minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
373 struct minstrel_mcs_group_data *mg;
377 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
378 mg = &mi->groups[mi->sample_group];
383 if (++mg->index >= MCS_GROUP_RATES) {
385 if (++mg->column >= ARRAY_SIZE(sample_table))
393 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx,
396 int group, orig_group;
398 orig_group = group = *idx / MCS_GROUP_RATES;
402 if (!mi->groups[group].supported)
405 if (minstrel_mcs_groups[group].streams >
406 minstrel_mcs_groups[orig_group].streams)
410 *idx = mi->groups[group].max_tp_rate;
412 *idx = mi->groups[group].max_tp_rate2;
418 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
420 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
421 struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
424 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
427 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
430 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
431 if (likely(sta->ampdu_mlme.tid_tx[tid]))
434 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
437 ieee80211_start_tx_ba_session(pubsta, tid, 5000);
441 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
442 struct ieee80211_sta *sta, void *priv_sta,
445 struct minstrel_ht_sta_priv *msp = priv_sta;
446 struct minstrel_ht_sta *mi = &msp->ht;
447 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
448 struct ieee80211_tx_rate *ar = info->status.rates;
449 struct minstrel_rate_stats *rate, *rate2;
450 struct minstrel_priv *mp = priv;
455 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
457 /* This packet was aggregated but doesn't carry status info */
458 if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
459 !(info->flags & IEEE80211_TX_STAT_AMPDU))
462 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
463 info->status.ampdu_ack_len =
464 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
465 info->status.ampdu_len = 1;
469 mi->ampdu_len += info->status.ampdu_len;
471 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
472 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
473 mi->sample_tries = 1;
477 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
478 mi->sample_packets += info->status.ampdu_len;
480 last = !minstrel_ht_txstat_valid(mp, &ar[0]);
481 for (i = 0; !last; i++) {
482 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
483 !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
485 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
488 rate->success += info->status.ampdu_ack_len;
490 rate->attempts += ar[i].count * info->status.ampdu_len;
494 * check for sudden death of spatial multiplexing,
495 * downgrade to a lower number of streams if necessary.
497 rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
498 if (rate->attempts > 30 &&
499 MINSTREL_FRAC(rate->success, rate->attempts) <
500 MINSTREL_FRAC(20, 100))
501 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
503 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
504 if (rate2->attempts > 30 &&
505 MINSTREL_FRAC(rate2->success, rate2->attempts) <
506 MINSTREL_FRAC(20, 100))
507 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
509 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
510 minstrel_ht_update_stats(mp, mi);
511 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
512 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
513 minstrel_aggr_check(sta, skb);
518 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
521 struct minstrel_rate_stats *mr;
522 const struct mcs_group *group;
523 unsigned int tx_time, tx_time_rtscts, tx_time_data;
524 unsigned int cw = mp->cw_min;
525 unsigned int ctime = 0;
526 unsigned int t_slot = 9; /* FIXME */
527 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
528 unsigned int overhead = 0, overhead_rtscts = 0;
530 mr = minstrel_get_ratestats(mi, index);
531 if (mr->probability < MINSTREL_FRAC(1, 10)) {
533 mr->retry_count_rtscts = 1;
538 mr->retry_count_rtscts = 2;
539 mr->retry_updated = true;
541 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
542 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
544 /* Contention time for first 2 tries */
545 ctime = (t_slot * cw) >> 1;
546 cw = min((cw << 1) | 1, mp->cw_max);
547 ctime += (t_slot * cw) >> 1;
548 cw = min((cw << 1) | 1, mp->cw_max);
550 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
551 overhead = mi->overhead;
552 overhead_rtscts = mi->overhead_rtscts;
555 /* Total TX time for data and Contention after first 2 tries */
556 tx_time = ctime + 2 * (overhead + tx_time_data);
557 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
559 /* See how many more tries we can fit inside segment size */
561 /* Contention time for this try */
562 ctime = (t_slot * cw) >> 1;
563 cw = min((cw << 1) | 1, mp->cw_max);
565 /* Total TX time after this try */
566 tx_time += ctime + overhead + tx_time_data;
567 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
569 if (tx_time_rtscts < mp->segment_size)
570 mr->retry_count_rtscts++;
571 } while ((tx_time < mp->segment_size) &&
572 (++mr->retry_count < mp->max_retry));
577 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
578 struct ieee80211_tx_rate *rate, int index,
579 bool sample, bool rtscts)
581 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
582 struct minstrel_rate_stats *mr;
584 mr = minstrel_get_ratestats(mi, index);
585 if (!mr->retry_updated)
586 minstrel_calc_retransmit(mp, mi, index);
590 else if (mr->probability < MINSTREL_FRAC(20, 100))
593 rate->count = mr->retry_count_rtscts;
595 rate->count = mr->retry_count;
599 rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS;
601 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
602 rate->idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
606 rate->flags |= IEEE80211_TX_RC_MCS | group->flags;
607 rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES;
611 minstrel_get_duration(int index)
613 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
614 return group->duration[index % MCS_GROUP_RATES];
618 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
620 struct minstrel_rate_stats *mr;
621 struct minstrel_mcs_group_data *mg;
622 unsigned int sample_dur, sample_group;
625 if (mi->sample_wait > 0) {
630 if (!mi->sample_tries)
633 mg = &mi->groups[mi->sample_group];
634 sample_idx = sample_table[mg->column][mg->index];
635 mr = &mg->rates[sample_idx];
636 sample_group = mi->sample_group;
637 sample_idx += sample_group * MCS_GROUP_RATES;
638 minstrel_next_sample_idx(mi);
641 * Sampling might add some overhead (RTS, no aggregation)
642 * to the frame. Hence, don't use sampling for the currently
645 if (sample_idx == mi->max_tp_rate)
648 * When not using MRR, do not sample if the probability is already
649 * higher than 95% to avoid wasting airtime
651 if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100)))
655 * Make sure that lower rates get sampled only occasionally,
656 * if the link is working perfectly.
658 sample_dur = minstrel_get_duration(sample_idx);
659 if (sample_dur >= minstrel_get_duration(mi->max_tp_rate2) &&
660 (mi->max_prob_streams <
661 minstrel_mcs_groups[sample_group].streams ||
662 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
663 if (mr->sample_skipped < 20)
666 if (mi->sample_slow++ > 2)
675 minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp,
676 struct minstrel_ht_sta *mi, bool val)
678 u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported;
680 if (!supported || !mi->cck_supported_short)
683 if (supported & (mi->cck_supported_short << (val * 4)))
686 supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4);
687 mi->groups[MINSTREL_CCK_GROUP].supported = supported;
691 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
692 struct ieee80211_tx_rate_control *txrc)
694 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
695 struct ieee80211_tx_rate *ar = info->status.rates;
696 struct minstrel_ht_sta_priv *msp = priv_sta;
697 struct minstrel_ht_sta *mi = &msp->ht;
698 struct minstrel_priv *mp = priv;
702 if (rate_control_send_low(sta, priv_sta, txrc))
706 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
708 info->flags |= mi->tx_flags;
709 minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble);
711 /* Don't use EAPOL frames for sampling on non-mrr hw */
712 if (mp->hw->max_rates == 1 &&
713 txrc->skb->protocol == cpu_to_be16(ETH_P_PAE))
716 sample_idx = minstrel_get_sample_rate(mp, mi);
718 #ifdef CONFIG_MAC80211_DEBUGFS
719 /* use fixed index if set */
720 if (mp->fixed_rate_idx != -1) {
721 mi->max_tp_rate = mp->fixed_rate_idx;
722 mi->max_tp_rate2 = mp->fixed_rate_idx;
723 mi->max_prob_rate = mp->fixed_rate_idx;
728 if (sample_idx >= 0) {
730 minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
732 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
734 minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
738 if (mp->hw->max_rates >= 3) {
740 * At least 3 tx rates supported, use
741 * sample_rate -> max_tp_rate -> max_prob_rate for sampling and
742 * max_tp_rate -> max_tp_rate2 -> max_prob_rate by default.
745 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
748 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2,
751 minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate,
756 } else if (mp->hw->max_rates == 2) {
758 * Only 2 tx rates supported, use
759 * sample_rate -> max_prob_rate for sampling and
760 * max_tp_rate -> max_prob_rate by default.
762 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_prob_rate,
768 /* Not using MRR, only use the first rate */
776 if (mi->total_packets == ~0) {
777 mi->total_packets = 0;
778 mi->sample_packets = 0;
783 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
784 struct ieee80211_supported_band *sband,
785 struct ieee80211_sta *sta)
789 if (sband->band != IEEE80211_BAND_2GHZ)
792 mi->cck_supported = 0;
793 mi->cck_supported_short = 0;
794 for (i = 0; i < 4; i++) {
795 if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
798 mi->cck_supported |= BIT(i);
799 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
800 mi->cck_supported_short |= BIT(i);
803 mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported;
807 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
808 struct ieee80211_sta *sta, void *priv_sta)
810 struct minstrel_priv *mp = priv;
811 struct minstrel_ht_sta_priv *msp = priv_sta;
812 struct minstrel_ht_sta *mi = &msp->ht;
813 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
814 u16 sta_cap = sta->ht_cap.cap;
820 /* fall back to the old minstrel for legacy stations */
821 if (!sta->ht_cap.ht_supported)
824 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
825 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1);
828 memset(mi, 0, sizeof(*mi));
829 mi->stats_update = jiffies;
831 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1);
832 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1) + ack_dur;
833 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
835 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
837 /* When using MRR, sample more on the first attempt, without delay */
839 mi->sample_count = 16;
842 mi->sample_count = 8;
845 mi->sample_tries = 4;
847 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
848 IEEE80211_HT_CAP_RX_STBC_SHIFT;
849 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
851 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
852 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
854 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
855 mi->groups[i].supported = 0;
856 if (i == MINSTREL_CCK_GROUP) {
857 minstrel_ht_update_cck(mp, mi, sband, sta);
861 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
862 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
863 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
866 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
871 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
872 sta->bandwidth < IEEE80211_STA_RX_BW_40)
875 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
876 if (sta->smps_mode == IEEE80211_SMPS_STATIC &&
877 minstrel_mcs_groups[i].streams > 1)
880 mi->groups[i].supported =
881 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
883 if (mi->groups[i].supported)
894 memset(&msp->legacy, 0, sizeof(msp->legacy));
895 msp->legacy.r = msp->ratelist;
896 msp->legacy.sample_table = msp->sample_table;
897 return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy);
901 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
902 struct ieee80211_sta *sta, void *priv_sta)
904 minstrel_ht_update_caps(priv, sband, sta, priv_sta);
908 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
909 struct ieee80211_sta *sta, void *priv_sta,
912 minstrel_ht_update_caps(priv, sband, sta, priv_sta);
916 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
918 struct ieee80211_supported_band *sband;
919 struct minstrel_ht_sta_priv *msp;
920 struct minstrel_priv *mp = priv;
921 struct ieee80211_hw *hw = mp->hw;
925 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
926 sband = hw->wiphy->bands[i];
927 if (sband && sband->n_bitrates > max_rates)
928 max_rates = sband->n_bitrates;
931 msp = kzalloc(sizeof(*msp), gfp);
935 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
939 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
940 if (!msp->sample_table)
946 kfree(msp->ratelist);
953 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
955 struct minstrel_ht_sta_priv *msp = priv_sta;
957 kfree(msp->sample_table);
958 kfree(msp->ratelist);
963 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
965 return mac80211_minstrel.alloc(hw, debugfsdir);
969 minstrel_ht_free(void *priv)
971 mac80211_minstrel.free(priv);
974 static struct rate_control_ops mac80211_minstrel_ht = {
975 .name = "minstrel_ht",
976 .tx_status = minstrel_ht_tx_status,
977 .get_rate = minstrel_ht_get_rate,
978 .rate_init = minstrel_ht_rate_init,
979 .rate_update = minstrel_ht_rate_update,
980 .alloc_sta = minstrel_ht_alloc_sta,
981 .free_sta = minstrel_ht_free_sta,
982 .alloc = minstrel_ht_alloc,
983 .free = minstrel_ht_free,
984 #ifdef CONFIG_MAC80211_DEBUGFS
985 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
986 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
992 init_sample_table(void)
995 u8 rnd[MCS_GROUP_RATES];
997 memset(sample_table, 0xff, sizeof(sample_table));
998 for (col = 0; col < SAMPLE_COLUMNS; col++) {
999 for (i = 0; i < MCS_GROUP_RATES; i++) {
1000 get_random_bytes(rnd, sizeof(rnd));
1001 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1003 while (sample_table[col][new_idx] != 0xff)
1004 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1006 sample_table[col][new_idx] = i;
1012 rc80211_minstrel_ht_init(void)
1014 init_sample_table();
1015 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1019 rc80211_minstrel_ht_exit(void)
1021 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);