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) ((MCS_NBITS + (bps) - 1) / (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];
130 * Look up an MCS group index based on mac80211 rate information
133 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
135 return GROUP_IDX((rate->idx / MCS_GROUP_RATES) + 1,
136 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
137 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
140 static struct minstrel_rate_stats *
141 minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
142 struct ieee80211_tx_rate *rate)
146 if (rate->flags & IEEE80211_TX_RC_MCS) {
147 group = minstrel_ht_get_group_idx(rate);
148 idx = rate->idx % MCS_GROUP_RATES;
150 group = MINSTREL_CCK_GROUP;
152 for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++)
153 if (rate->idx == mp->cck_rates[idx])
157 if (!(mi->groups[group].supported & BIT(idx)))
160 return &mi->groups[group].rates[idx];
163 static inline struct minstrel_rate_stats *
164 minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
166 return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
171 * Recalculate success probabilities and counters for a rate using EWMA
174 minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr)
176 if (unlikely(mr->attempts > 0)) {
177 mr->sample_skipped = 0;
178 mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
180 mr->probability = mr->cur_prob;
182 mr->probability = minstrel_ewma(mr->probability,
183 mr->cur_prob, EWMA_LEVEL);
184 mr->att_hist += mr->attempts;
185 mr->succ_hist += mr->success;
187 mr->sample_skipped++;
189 mr->last_success = mr->success;
190 mr->last_attempts = mr->attempts;
196 * Calculate throughput based on the average A-MPDU length, taking into account
197 * the expected number of retransmissions and their expected length
200 minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
202 struct minstrel_rate_stats *mr;
203 unsigned int nsecs = 0;
206 mr = &mi->groups[group].rates[rate];
208 if (mr->probability < MINSTREL_FRAC(1, 10)) {
213 if (group != MINSTREL_CCK_GROUP)
214 nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
216 nsecs += minstrel_mcs_groups[group].duration[rate];
217 tp = 1000000 * ((mr->probability * 1000) / nsecs);
219 mr->cur_tp = MINSTREL_TRUNC(tp);
223 * Update rate statistics and select new primary rates
225 * Rules for rate selection:
226 * - max_prob_rate must use only one stream, as a tradeoff between delivery
227 * probability and throughput during strong fluctuations
228 * - as long as the max prob rate has a probability of more than 3/4, pick
229 * higher throughput rates, even if the probablity is a bit lower
232 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
234 struct minstrel_mcs_group_data *mg;
235 struct minstrel_rate_stats *mr;
236 int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
239 if (mi->ampdu_packets > 0) {
240 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
241 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
243 mi->ampdu_packets = 0;
247 mi->sample_count = 0;
249 mi->max_tp_rate2 = 0;
250 mi->max_prob_rate = 0;
252 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
258 mg = &mi->groups[group];
263 mg->max_tp_rate2 = 0;
264 mg->max_prob_rate = 0;
267 for (i = 0; i < MCS_GROUP_RATES; i++) {
268 if (!(mg->supported & BIT(i)))
272 mr->retry_updated = false;
273 index = MCS_GROUP_RATES * group + i;
274 minstrel_calc_rate_ewma(mr);
275 minstrel_ht_calc_tp(mi, group, i);
280 if ((mr->cur_tp > cur_prob_tp && mr->probability >
281 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
282 mg->max_prob_rate = index;
283 cur_prob = mr->probability;
284 cur_prob_tp = mr->cur_tp;
287 if (mr->cur_tp > cur_tp) {
288 swap(index, mg->max_tp_rate);
290 mr = minstrel_get_ratestats(mi, index);
293 if (index >= mg->max_tp_rate)
296 if (mr->cur_tp > cur_tp2) {
297 mg->max_tp_rate2 = index;
298 cur_tp2 = mr->cur_tp;
303 /* try to sample all available rates during each interval */
304 mi->sample_count *= 8;
310 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
311 mg = &mi->groups[group];
315 mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
316 if (cur_tp < mr->cur_tp) {
317 mi->max_tp_rate2 = mi->max_tp_rate;
319 mi->max_tp_rate = mg->max_tp_rate;
321 mi->max_prob_streams = minstrel_mcs_groups[group].streams - 1;
324 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
325 if (cur_tp2 < mr->cur_tp) {
326 mi->max_tp_rate2 = mg->max_tp_rate2;
327 cur_tp2 = mr->cur_tp;
331 if (mi->max_prob_streams < 1)
332 mi->max_prob_streams = 1;
334 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
335 mg = &mi->groups[group];
338 mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
339 if (cur_prob_tp < mr->cur_tp &&
340 minstrel_mcs_groups[group].streams <= mi->max_prob_streams) {
341 mi->max_prob_rate = mg->max_prob_rate;
342 cur_prob = mr->cur_prob;
343 cur_prob_tp = mr->cur_tp;
348 mi->stats_update = jiffies;
352 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
360 if (rate->flags & IEEE80211_TX_RC_MCS)
363 return rate->idx == mp->cck_rates[0] ||
364 rate->idx == mp->cck_rates[1] ||
365 rate->idx == mp->cck_rates[2] ||
366 rate->idx == mp->cck_rates[3];
370 minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
372 struct minstrel_mcs_group_data *mg;
376 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
377 mg = &mi->groups[mi->sample_group];
382 if (++mg->index >= MCS_GROUP_RATES) {
384 if (++mg->column >= ARRAY_SIZE(sample_table))
392 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx,
395 int group, orig_group;
397 orig_group = group = *idx / MCS_GROUP_RATES;
401 if (!mi->groups[group].supported)
404 if (minstrel_mcs_groups[group].streams >
405 minstrel_mcs_groups[orig_group].streams)
409 *idx = mi->groups[group].max_tp_rate;
411 *idx = mi->groups[group].max_tp_rate2;
417 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
419 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
420 struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
423 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
426 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
429 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
430 if (likely(sta->ampdu_mlme.tid_tx[tid]))
433 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
436 ieee80211_start_tx_ba_session(pubsta, tid, 5000);
440 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
441 struct ieee80211_sta *sta, void *priv_sta,
444 struct minstrel_ht_sta_priv *msp = priv_sta;
445 struct minstrel_ht_sta *mi = &msp->ht;
446 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
447 struct ieee80211_tx_rate *ar = info->status.rates;
448 struct minstrel_rate_stats *rate, *rate2;
449 struct minstrel_priv *mp = priv;
454 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
456 /* This packet was aggregated but doesn't carry status info */
457 if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
458 !(info->flags & IEEE80211_TX_STAT_AMPDU))
461 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
462 info->status.ampdu_ack_len =
463 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
464 info->status.ampdu_len = 1;
468 mi->ampdu_len += info->status.ampdu_len;
470 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
471 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
472 mi->sample_tries = 1;
476 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
477 mi->sample_packets += info->status.ampdu_len;
479 last = !minstrel_ht_txstat_valid(mp, &ar[0]);
480 for (i = 0; !last; i++) {
481 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
482 !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
484 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
487 rate->success += info->status.ampdu_ack_len;
489 rate->attempts += ar[i].count * info->status.ampdu_len;
493 * check for sudden death of spatial multiplexing,
494 * downgrade to a lower number of streams if necessary.
496 rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
497 if (rate->attempts > 30 &&
498 MINSTREL_FRAC(rate->success, rate->attempts) <
499 MINSTREL_FRAC(20, 100))
500 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
502 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
503 if (rate2->attempts > 30 &&
504 MINSTREL_FRAC(rate2->success, rate2->attempts) <
505 MINSTREL_FRAC(20, 100))
506 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
508 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
509 minstrel_ht_update_stats(mp, mi);
510 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
511 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
512 minstrel_aggr_check(sta, skb);
517 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
520 struct minstrel_rate_stats *mr;
521 const struct mcs_group *group;
522 unsigned int tx_time, tx_time_rtscts, tx_time_data;
523 unsigned int cw = mp->cw_min;
524 unsigned int ctime = 0;
525 unsigned int t_slot = 9; /* FIXME */
526 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
527 unsigned int overhead = 0, overhead_rtscts = 0;
529 mr = minstrel_get_ratestats(mi, index);
530 if (mr->probability < MINSTREL_FRAC(1, 10)) {
532 mr->retry_count_rtscts = 1;
537 mr->retry_count_rtscts = 2;
538 mr->retry_updated = true;
540 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
541 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
543 /* Contention time for first 2 tries */
544 ctime = (t_slot * cw) >> 1;
545 cw = min((cw << 1) | 1, mp->cw_max);
546 ctime += (t_slot * cw) >> 1;
547 cw = min((cw << 1) | 1, mp->cw_max);
549 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
550 overhead = mi->overhead;
551 overhead_rtscts = mi->overhead_rtscts;
554 /* Total TX time for data and Contention after first 2 tries */
555 tx_time = ctime + 2 * (overhead + tx_time_data);
556 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
558 /* See how many more tries we can fit inside segment size */
560 /* Contention time for this try */
561 ctime = (t_slot * cw) >> 1;
562 cw = min((cw << 1) | 1, mp->cw_max);
564 /* Total TX time after this try */
565 tx_time += ctime + overhead + tx_time_data;
566 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
568 if (tx_time_rtscts < mp->segment_size)
569 mr->retry_count_rtscts++;
570 } while ((tx_time < mp->segment_size) &&
571 (++mr->retry_count < mp->max_retry));
576 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
577 struct ieee80211_tx_rate *rate, int index,
578 bool sample, bool rtscts)
580 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
581 struct minstrel_rate_stats *mr;
583 mr = minstrel_get_ratestats(mi, index);
584 if (!mr->retry_updated)
585 minstrel_calc_retransmit(mp, mi, index);
589 else if (mr->probability < MINSTREL_FRAC(20, 100))
592 rate->count = mr->retry_count_rtscts;
594 rate->count = mr->retry_count;
598 rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS;
600 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
601 rate->idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
605 rate->flags |= IEEE80211_TX_RC_MCS | group->flags;
606 rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES;
610 minstrel_get_duration(int index)
612 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
613 return group->duration[index % MCS_GROUP_RATES];
617 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
619 struct minstrel_rate_stats *mr;
620 struct minstrel_mcs_group_data *mg;
621 unsigned int sample_dur, sample_group;
624 if (mi->sample_wait > 0) {
629 if (!mi->sample_tries)
632 mg = &mi->groups[mi->sample_group];
633 sample_idx = sample_table[mg->column][mg->index];
634 mr = &mg->rates[sample_idx];
635 sample_group = mi->sample_group;
636 sample_idx += sample_group * MCS_GROUP_RATES;
637 minstrel_next_sample_idx(mi);
640 * Sampling might add some overhead (RTS, no aggregation)
641 * to the frame. Hence, don't use sampling for the currently
644 if (sample_idx == mi->max_tp_rate)
647 * When not using MRR, do not sample if the probability is already
648 * higher than 95% to avoid wasting airtime
650 if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100)))
654 * Make sure that lower rates get sampled only occasionally,
655 * if the link is working perfectly.
657 sample_dur = minstrel_get_duration(sample_idx);
658 if (sample_dur >= minstrel_get_duration(mi->max_tp_rate2) &&
659 (mi->max_prob_streams <
660 minstrel_mcs_groups[sample_group].streams ||
661 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
662 if (mr->sample_skipped < 20)
665 if (mi->sample_slow++ > 2)
674 minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp,
675 struct minstrel_ht_sta *mi, bool val)
677 u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported;
679 if (!supported || !mi->cck_supported_short)
682 if (supported & (mi->cck_supported_short << (val * 4)))
685 supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4);
686 mi->groups[MINSTREL_CCK_GROUP].supported = supported;
690 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
691 struct ieee80211_tx_rate_control *txrc)
693 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
694 struct ieee80211_tx_rate *ar = info->status.rates;
695 struct minstrel_ht_sta_priv *msp = priv_sta;
696 struct minstrel_ht_sta *mi = &msp->ht;
697 struct minstrel_priv *mp = priv;
701 if (rate_control_send_low(sta, priv_sta, txrc))
705 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
707 info->flags |= mi->tx_flags;
708 minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble);
710 /* Don't use EAPOL frames for sampling on non-mrr hw */
711 if (mp->hw->max_rates == 1 &&
712 txrc->skb->protocol == cpu_to_be16(ETH_P_PAE))
715 sample_idx = minstrel_get_sample_rate(mp, mi);
717 #ifdef CONFIG_MAC80211_DEBUGFS
718 /* use fixed index if set */
719 if (mp->fixed_rate_idx != -1) {
720 mi->max_tp_rate = mp->fixed_rate_idx;
721 mi->max_tp_rate2 = mp->fixed_rate_idx;
722 mi->max_prob_rate = mp->fixed_rate_idx;
727 if (sample_idx >= 0) {
729 minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
731 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
733 minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
737 if (mp->hw->max_rates >= 3) {
739 * At least 3 tx rates supported, use
740 * sample_rate -> max_tp_rate -> max_prob_rate for sampling and
741 * max_tp_rate -> max_tp_rate2 -> max_prob_rate by default.
744 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
747 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2,
750 minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate,
755 } else if (mp->hw->max_rates == 2) {
757 * Only 2 tx rates supported, use
758 * sample_rate -> max_prob_rate for sampling and
759 * max_tp_rate -> max_prob_rate by default.
761 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_prob_rate,
767 /* Not using MRR, only use the first rate */
775 if (mi->total_packets == ~0) {
776 mi->total_packets = 0;
777 mi->sample_packets = 0;
782 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
783 struct ieee80211_supported_band *sband,
784 struct ieee80211_sta *sta)
788 if (sband->band != IEEE80211_BAND_2GHZ)
791 mi->cck_supported = 0;
792 mi->cck_supported_short = 0;
793 for (i = 0; i < 4; i++) {
794 if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
797 mi->cck_supported |= BIT(i);
798 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
799 mi->cck_supported_short |= BIT(i);
802 mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported;
806 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
807 struct ieee80211_sta *sta, void *priv_sta)
809 struct minstrel_priv *mp = priv;
810 struct minstrel_ht_sta_priv *msp = priv_sta;
811 struct minstrel_ht_sta *mi = &msp->ht;
812 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
813 u16 sta_cap = sta->ht_cap.cap;
819 /* fall back to the old minstrel for legacy stations */
820 if (!sta->ht_cap.ht_supported)
823 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
824 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1);
827 memset(mi, 0, sizeof(*mi));
828 mi->stats_update = jiffies;
830 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1);
831 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1) + ack_dur;
832 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
834 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
836 /* When using MRR, sample more on the first attempt, without delay */
838 mi->sample_count = 16;
841 mi->sample_count = 8;
844 mi->sample_tries = 4;
846 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
847 IEEE80211_HT_CAP_RX_STBC_SHIFT;
848 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
850 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
851 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
853 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
854 mi->groups[i].supported = 0;
855 if (i == MINSTREL_CCK_GROUP) {
856 minstrel_ht_update_cck(mp, mi, sband, sta);
860 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
861 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
862 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
865 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
870 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
871 sta->bandwidth < IEEE80211_STA_RX_BW_40)
874 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
875 if (sta->smps_mode == IEEE80211_SMPS_STATIC &&
876 minstrel_mcs_groups[i].streams > 1)
879 mi->groups[i].supported =
880 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
882 if (mi->groups[i].supported)
893 memset(&msp->legacy, 0, sizeof(msp->legacy));
894 msp->legacy.r = msp->ratelist;
895 msp->legacy.sample_table = msp->sample_table;
896 return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy);
900 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
901 struct ieee80211_sta *sta, void *priv_sta)
903 minstrel_ht_update_caps(priv, sband, sta, priv_sta);
907 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
908 struct ieee80211_sta *sta, void *priv_sta,
911 minstrel_ht_update_caps(priv, sband, sta, priv_sta);
915 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
917 struct ieee80211_supported_band *sband;
918 struct minstrel_ht_sta_priv *msp;
919 struct minstrel_priv *mp = priv;
920 struct ieee80211_hw *hw = mp->hw;
924 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
925 sband = hw->wiphy->bands[i];
926 if (sband && sband->n_bitrates > max_rates)
927 max_rates = sband->n_bitrates;
930 msp = kzalloc(sizeof(*msp), gfp);
934 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
938 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
939 if (!msp->sample_table)
945 kfree(msp->ratelist);
952 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
954 struct minstrel_ht_sta_priv *msp = priv_sta;
956 kfree(msp->sample_table);
957 kfree(msp->ratelist);
962 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
964 return mac80211_minstrel.alloc(hw, debugfsdir);
968 minstrel_ht_free(void *priv)
970 mac80211_minstrel.free(priv);
973 static struct rate_control_ops mac80211_minstrel_ht = {
974 .name = "minstrel_ht",
975 .tx_status = minstrel_ht_tx_status,
976 .get_rate = minstrel_ht_get_rate,
977 .rate_init = minstrel_ht_rate_init,
978 .rate_update = minstrel_ht_rate_update,
979 .alloc_sta = minstrel_ht_alloc_sta,
980 .free_sta = minstrel_ht_free_sta,
981 .alloc = minstrel_ht_alloc,
982 .free = minstrel_ht_free,
983 #ifdef CONFIG_MAC80211_DEBUGFS
984 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
985 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
991 init_sample_table(void)
994 u8 rnd[MCS_GROUP_RATES];
996 memset(sample_table, 0xff, sizeof(sample_table));
997 for (col = 0; col < SAMPLE_COLUMNS; col++) {
998 for (i = 0; i < MCS_GROUP_RATES; i++) {
999 get_random_bytes(rnd, sizeof(rnd));
1000 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1002 while (sample_table[col][new_idx] != 0xff)
1003 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1005 sample_table[col][new_idx] = i;
1011 rc80211_minstrel_ht_init(void)
1013 init_sample_table();
1014 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1018 rc80211_minstrel_ht_exit(void)
1020 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);