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 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);
151 idx = rate->idx % MCS_GROUP_RATES;
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];
229 tp = 1000000 * ((mr->probability * 1000) / nsecs);
231 mr->cur_tp = MINSTREL_TRUNC(tp);
235 * Update rate statistics and select new primary rates
237 * Rules for rate selection:
238 * - max_prob_rate must use only one stream, as a tradeoff between delivery
239 * probability and throughput during strong fluctuations
240 * - as long as the max prob rate has a probability of more than 3/4, pick
241 * higher throughput rates, even if the probablity is a bit lower
244 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
246 struct minstrel_mcs_group_data *mg;
247 struct minstrel_rate_stats *mr;
248 int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
250 bool mi_rates_valid = false;
252 if (mi->ampdu_packets > 0) {
253 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
254 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
256 mi->ampdu_packets = 0;
260 mi->sample_count = 0;
262 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
263 bool mg_rates_valid = false;
270 mg = &mi->groups[group];
276 for (i = 0; i < MCS_GROUP_RATES; i++) {
277 if (!(mg->supported & BIT(i)))
280 /* initialize rates selections starting indexes */
281 if (!mg_rates_valid) {
282 mg->max_tp_rate = mg->max_tp_rate2 =
283 mg->max_prob_rate = i;
284 if (!mi_rates_valid) {
285 mi->max_tp_rate = mi->max_tp_rate2 =
286 mi->max_prob_rate = i;
287 mi_rates_valid = true;
289 mg_rates_valid = true;
293 mr->retry_updated = false;
294 index = MCS_GROUP_RATES * group + i;
295 minstrel_calc_rate_ewma(mr);
296 minstrel_ht_calc_tp(mi, group, i);
301 if ((mr->cur_tp > cur_prob_tp && mr->probability >
302 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
303 mg->max_prob_rate = index;
304 cur_prob = mr->probability;
305 cur_prob_tp = mr->cur_tp;
308 if (mr->cur_tp > cur_tp) {
309 swap(index, mg->max_tp_rate);
311 mr = minstrel_get_ratestats(mi, index);
314 if (index >= mg->max_tp_rate)
317 if (mr->cur_tp > cur_tp2) {
318 mg->max_tp_rate2 = index;
319 cur_tp2 = mr->cur_tp;
324 /* try to sample all available rates during each interval */
325 mi->sample_count *= 8;
331 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
332 mg = &mi->groups[group];
336 mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
337 if (cur_tp < mr->cur_tp) {
338 mi->max_tp_rate2 = mi->max_tp_rate;
340 mi->max_tp_rate = mg->max_tp_rate;
342 mi->max_prob_streams = minstrel_mcs_groups[group].streams - 1;
345 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
346 if (cur_tp2 < mr->cur_tp) {
347 mi->max_tp_rate2 = mg->max_tp_rate2;
348 cur_tp2 = mr->cur_tp;
352 if (mi->max_prob_streams < 1)
353 mi->max_prob_streams = 1;
355 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
356 mg = &mi->groups[group];
359 mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
360 if (cur_prob_tp < mr->cur_tp &&
361 minstrel_mcs_groups[group].streams <= mi->max_prob_streams) {
362 mi->max_prob_rate = mg->max_prob_rate;
363 cur_prob = mr->cur_prob;
364 cur_prob_tp = mr->cur_tp;
368 #ifdef CONFIG_MAC80211_DEBUGFS
369 /* use fixed index if set */
370 if (mp->fixed_rate_idx != -1) {
371 mi->max_tp_rate = mp->fixed_rate_idx;
372 mi->max_tp_rate2 = mp->fixed_rate_idx;
373 mi->max_prob_rate = mp->fixed_rate_idx;
377 mi->stats_update = jiffies;
381 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
389 if (rate->flags & IEEE80211_TX_RC_MCS)
392 return rate->idx == mp->cck_rates[0] ||
393 rate->idx == mp->cck_rates[1] ||
394 rate->idx == mp->cck_rates[2] ||
395 rate->idx == mp->cck_rates[3];
399 minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
401 struct minstrel_mcs_group_data *mg;
405 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
406 mg = &mi->groups[mi->sample_group];
411 if (++mg->index >= MCS_GROUP_RATES) {
413 if (++mg->column >= ARRAY_SIZE(sample_table))
421 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx,
424 int group, orig_group;
426 orig_group = group = *idx / MCS_GROUP_RATES;
430 if (!mi->groups[group].supported)
433 if (minstrel_mcs_groups[group].streams >
434 minstrel_mcs_groups[orig_group].streams)
438 *idx = mi->groups[group].max_tp_rate;
440 *idx = mi->groups[group].max_tp_rate2;
446 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
448 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
449 struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
452 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
455 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
458 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
459 if (likely(sta->ampdu_mlme.tid_tx[tid]))
462 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
465 ieee80211_start_tx_ba_session(pubsta, tid, 5000);
469 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
470 struct ieee80211_sta *sta, void *priv_sta,
473 struct minstrel_ht_sta_priv *msp = priv_sta;
474 struct minstrel_ht_sta *mi = &msp->ht;
475 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
476 struct ieee80211_tx_rate *ar = info->status.rates;
477 struct minstrel_rate_stats *rate, *rate2;
478 struct minstrel_priv *mp = priv;
479 bool last, update = false;
483 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
485 /* This packet was aggregated but doesn't carry status info */
486 if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
487 !(info->flags & IEEE80211_TX_STAT_AMPDU))
490 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
491 info->status.ampdu_ack_len =
492 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
493 info->status.ampdu_len = 1;
497 mi->ampdu_len += info->status.ampdu_len;
499 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
500 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
501 mi->sample_tries = 1;
505 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
506 mi->sample_packets += info->status.ampdu_len;
508 last = !minstrel_ht_txstat_valid(mp, &ar[0]);
509 for (i = 0; !last; i++) {
510 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
511 !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
513 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
516 rate->success += info->status.ampdu_ack_len;
518 rate->attempts += ar[i].count * info->status.ampdu_len;
522 * check for sudden death of spatial multiplexing,
523 * downgrade to a lower number of streams if necessary.
525 rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
526 if (rate->attempts > 30 &&
527 MINSTREL_FRAC(rate->success, rate->attempts) <
528 MINSTREL_FRAC(20, 100)) {
529 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
533 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
534 if (rate2->attempts > 30 &&
535 MINSTREL_FRAC(rate2->success, rate2->attempts) <
536 MINSTREL_FRAC(20, 100)) {
537 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
541 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
543 minstrel_ht_update_stats(mp, mi);
544 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
545 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
546 minstrel_aggr_check(sta, skb);
550 minstrel_ht_update_rates(mp, mi);
554 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
557 struct minstrel_rate_stats *mr;
558 const struct mcs_group *group;
559 unsigned int tx_time, tx_time_rtscts, tx_time_data;
560 unsigned int cw = mp->cw_min;
561 unsigned int ctime = 0;
562 unsigned int t_slot = 9; /* FIXME */
563 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
564 unsigned int overhead = 0, overhead_rtscts = 0;
566 mr = minstrel_get_ratestats(mi, index);
567 if (mr->probability < MINSTREL_FRAC(1, 10)) {
569 mr->retry_count_rtscts = 1;
574 mr->retry_count_rtscts = 2;
575 mr->retry_updated = true;
577 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
578 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
580 /* Contention time for first 2 tries */
581 ctime = (t_slot * cw) >> 1;
582 cw = min((cw << 1) | 1, mp->cw_max);
583 ctime += (t_slot * cw) >> 1;
584 cw = min((cw << 1) | 1, mp->cw_max);
586 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
587 overhead = mi->overhead;
588 overhead_rtscts = mi->overhead_rtscts;
591 /* Total TX time for data and Contention after first 2 tries */
592 tx_time = ctime + 2 * (overhead + tx_time_data);
593 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
595 /* See how many more tries we can fit inside segment size */
597 /* Contention time for this try */
598 ctime = (t_slot * cw) >> 1;
599 cw = min((cw << 1) | 1, mp->cw_max);
601 /* Total TX time after this try */
602 tx_time += ctime + overhead + tx_time_data;
603 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
605 if (tx_time_rtscts < mp->segment_size)
606 mr->retry_count_rtscts++;
607 } while ((tx_time < mp->segment_size) &&
608 (++mr->retry_count < mp->max_retry));
613 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
614 struct ieee80211_sta_rates *ratetbl, int offset, int index)
616 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
617 struct minstrel_rate_stats *mr;
621 mr = minstrel_get_ratestats(mi, index);
622 if (!mr->retry_updated)
623 minstrel_calc_retransmit(mp, mi, index);
625 if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) {
626 ratetbl->rate[offset].count = 2;
627 ratetbl->rate[offset].count_rts = 2;
628 ratetbl->rate[offset].count_cts = 2;
630 ratetbl->rate[offset].count = mr->retry_count;
631 ratetbl->rate[offset].count_cts = mr->retry_count;
632 ratetbl->rate[offset].count_rts = mr->retry_count_rtscts;
635 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
636 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
639 idx = index % MCS_GROUP_RATES +
640 (group->streams - 1) * MCS_GROUP_RATES;
641 flags = IEEE80211_TX_RC_MCS | group->flags;
645 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
646 flags |= IEEE80211_TX_RC_USE_RTS_CTS;
649 ratetbl->rate[offset].idx = idx;
650 ratetbl->rate[offset].flags = flags;
654 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
656 struct ieee80211_sta_rates *rates;
659 rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
663 /* Start with max_tp_rate */
664 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate);
666 if (mp->hw->max_rates >= 3) {
667 /* At least 3 tx rates supported, use max_tp_rate2 next */
668 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate2);
671 if (mp->hw->max_rates >= 2) {
673 * At least 2 tx rates supported, use max_prob_rate next */
674 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
677 rates->rate[i].idx = -1;
678 rate_control_set_rates(mp->hw, mi->sta, rates);
682 minstrel_get_duration(int index)
684 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
685 return group->duration[index % MCS_GROUP_RATES];
689 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
691 struct minstrel_rate_stats *mr;
692 struct minstrel_mcs_group_data *mg;
693 unsigned int sample_dur, sample_group;
696 if (mi->sample_wait > 0) {
701 if (!mi->sample_tries)
704 mg = &mi->groups[mi->sample_group];
705 sample_idx = sample_table[mg->column][mg->index];
706 mr = &mg->rates[sample_idx];
707 sample_group = mi->sample_group;
708 sample_idx += sample_group * MCS_GROUP_RATES;
709 minstrel_next_sample_idx(mi);
712 * Sampling might add some overhead (RTS, no aggregation)
713 * to the frame. Hence, don't use sampling for the currently
716 if (sample_idx == mi->max_tp_rate ||
717 sample_idx == mi->max_tp_rate2 ||
718 sample_idx == mi->max_prob_rate)
722 * Do not sample if the probability is already higher than 95%
723 * to avoid wasting airtime.
725 if (mr->probability > MINSTREL_FRAC(95, 100))
729 * Make sure that lower rates get sampled only occasionally,
730 * if the link is working perfectly.
732 sample_dur = minstrel_get_duration(sample_idx);
733 if (sample_dur >= minstrel_get_duration(mi->max_tp_rate2) &&
734 (mi->max_prob_streams <
735 minstrel_mcs_groups[sample_group].streams ||
736 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
737 if (mr->sample_skipped < 20)
740 if (mi->sample_slow++ > 2)
749 minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp,
750 struct minstrel_ht_sta *mi, bool val)
752 u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported;
754 if (!supported || !mi->cck_supported_short)
757 if (supported & (mi->cck_supported_short << (val * 4)))
760 supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4);
761 mi->groups[MINSTREL_CCK_GROUP].supported = supported;
765 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
766 struct ieee80211_tx_rate_control *txrc)
768 const struct mcs_group *sample_group;
769 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
770 struct ieee80211_tx_rate *rate = &info->status.rates[0];
771 struct minstrel_ht_sta_priv *msp = priv_sta;
772 struct minstrel_ht_sta *mi = &msp->ht;
773 struct minstrel_priv *mp = priv;
776 if (rate_control_send_low(sta, priv_sta, txrc))
780 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
782 info->flags |= mi->tx_flags;
783 minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble);
785 #ifdef CONFIG_MAC80211_DEBUGFS
786 if (mp->fixed_rate_idx != -1)
790 /* Don't use EAPOL frames for sampling on non-mrr hw */
791 if (mp->hw->max_rates == 1 &&
792 (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
795 sample_idx = minstrel_get_sample_rate(mp, mi);
800 if (mi->total_packets == ~0) {
801 mi->total_packets = 0;
802 mi->sample_packets = 0;
808 sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
809 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
812 if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
813 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
814 rate->idx = mp->cck_rates[idx];
819 rate->idx = sample_idx % MCS_GROUP_RATES +
820 (sample_group->streams - 1) * MCS_GROUP_RATES;
821 rate->flags = IEEE80211_TX_RC_MCS | sample_group->flags;
825 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
826 struct ieee80211_supported_band *sband,
827 struct ieee80211_sta *sta)
831 if (sband->band != IEEE80211_BAND_2GHZ)
834 if (!(mp->hw->flags & IEEE80211_HW_SUPPORTS_HT_CCK_RATES))
837 mi->cck_supported = 0;
838 mi->cck_supported_short = 0;
839 for (i = 0; i < 4; i++) {
840 if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
843 mi->cck_supported |= BIT(i);
844 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
845 mi->cck_supported_short |= BIT(i);
848 mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported;
852 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
853 struct cfg80211_chan_def *chandef,
854 struct ieee80211_sta *sta, void *priv_sta)
856 struct minstrel_priv *mp = priv;
857 struct minstrel_ht_sta_priv *msp = priv_sta;
858 struct minstrel_ht_sta *mi = &msp->ht;
859 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
860 u16 sta_cap = sta->ht_cap.cap;
866 /* fall back to the old minstrel for legacy stations */
867 if (!sta->ht_cap.ht_supported)
870 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
871 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1);
874 memset(mi, 0, sizeof(*mi));
877 mi->stats_update = jiffies;
879 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
880 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
881 mi->overhead += ack_dur;
882 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
884 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
886 /* When using MRR, sample more on the first attempt, without delay */
888 mi->sample_count = 16;
891 mi->sample_count = 8;
894 mi->sample_tries = 4;
896 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
897 IEEE80211_HT_CAP_RX_STBC_SHIFT;
898 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
900 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
901 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
903 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
904 mi->groups[i].supported = 0;
905 if (i == MINSTREL_CCK_GROUP) {
906 minstrel_ht_update_cck(mp, mi, sband, sta);
910 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
911 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
912 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
915 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
920 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
921 sta->bandwidth < IEEE80211_STA_RX_BW_40)
924 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
925 if (sta->smps_mode == IEEE80211_SMPS_STATIC &&
926 minstrel_mcs_groups[i].streams > 1)
929 mi->groups[i].supported =
930 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
932 if (mi->groups[i].supported)
939 /* create an initial rate table with the lowest supported rates */
940 minstrel_ht_update_stats(mp, mi);
941 minstrel_ht_update_rates(mp, mi);
947 memset(&msp->legacy, 0, sizeof(msp->legacy));
948 msp->legacy.r = msp->ratelist;
949 msp->legacy.sample_table = msp->sample_table;
950 return mac80211_minstrel.rate_init(priv, sband, chandef, sta,
955 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
956 struct cfg80211_chan_def *chandef,
957 struct ieee80211_sta *sta, void *priv_sta)
959 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
963 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
964 struct cfg80211_chan_def *chandef,
965 struct ieee80211_sta *sta, void *priv_sta,
968 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
972 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
974 struct ieee80211_supported_band *sband;
975 struct minstrel_ht_sta_priv *msp;
976 struct minstrel_priv *mp = priv;
977 struct ieee80211_hw *hw = mp->hw;
981 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
982 sband = hw->wiphy->bands[i];
983 if (sband && sband->n_bitrates > max_rates)
984 max_rates = sband->n_bitrates;
987 msp = kzalloc(sizeof(*msp), gfp);
991 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
995 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
996 if (!msp->sample_table)
1002 kfree(msp->ratelist);
1009 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1011 struct minstrel_ht_sta_priv *msp = priv_sta;
1013 kfree(msp->sample_table);
1014 kfree(msp->ratelist);
1019 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
1021 return mac80211_minstrel.alloc(hw, debugfsdir);
1025 minstrel_ht_free(void *priv)
1027 mac80211_minstrel.free(priv);
1030 static struct rate_control_ops mac80211_minstrel_ht = {
1031 .name = "minstrel_ht",
1032 .tx_status = minstrel_ht_tx_status,
1033 .get_rate = minstrel_ht_get_rate,
1034 .rate_init = minstrel_ht_rate_init,
1035 .rate_update = minstrel_ht_rate_update,
1036 .alloc_sta = minstrel_ht_alloc_sta,
1037 .free_sta = minstrel_ht_free_sta,
1038 .alloc = minstrel_ht_alloc,
1039 .free = minstrel_ht_free,
1040 #ifdef CONFIG_MAC80211_DEBUGFS
1041 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
1042 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
1048 init_sample_table(void)
1050 int col, i, new_idx;
1051 u8 rnd[MCS_GROUP_RATES];
1053 memset(sample_table, 0xff, sizeof(sample_table));
1054 for (col = 0; col < SAMPLE_COLUMNS; col++) {
1055 for (i = 0; i < MCS_GROUP_RATES; i++) {
1056 get_random_bytes(rnd, sizeof(rnd));
1057 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1059 while (sample_table[col][new_idx] != 0xff)
1060 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1062 sample_table[col][new_idx] = i;
1068 rc80211_minstrel_ht_init(void)
1070 init_sample_table();
1071 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1075 rc80211_minstrel_ht_exit(void)
1077 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);