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 * ((prob * 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 index = MCS_GROUP_RATES * group + i;
282 /* initialize rates selections starting indexes */
283 if (!mg_rates_valid) {
284 mg->max_tp_rate = mg->max_tp_rate2 =
285 mg->max_prob_rate = i;
286 if (!mi_rates_valid) {
287 mi->max_tp_rate = mi->max_tp_rate2 =
288 mi->max_prob_rate = index;
289 mi_rates_valid = true;
291 mg_rates_valid = true;
295 mr->retry_updated = false;
296 minstrel_calc_rate_ewma(mr);
297 minstrel_ht_calc_tp(mi, group, i);
302 if ((mr->cur_tp > cur_prob_tp && mr->probability >
303 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
304 mg->max_prob_rate = index;
305 cur_prob = mr->probability;
306 cur_prob_tp = mr->cur_tp;
309 if (mr->cur_tp > cur_tp) {
310 swap(index, mg->max_tp_rate);
312 mr = minstrel_get_ratestats(mi, index);
315 if (index >= mg->max_tp_rate)
318 if (mr->cur_tp > cur_tp2) {
319 mg->max_tp_rate2 = index;
320 cur_tp2 = mr->cur_tp;
325 /* try to sample all available rates during each interval */
326 mi->sample_count *= 8;
332 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
333 mg = &mi->groups[group];
337 mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
338 if (cur_tp < mr->cur_tp) {
339 mi->max_tp_rate2 = mi->max_tp_rate;
341 mi->max_tp_rate = mg->max_tp_rate;
343 mi->max_prob_streams = minstrel_mcs_groups[group].streams - 1;
346 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
347 if (cur_tp2 < mr->cur_tp) {
348 mi->max_tp_rate2 = mg->max_tp_rate2;
349 cur_tp2 = mr->cur_tp;
353 if (mi->max_prob_streams < 1)
354 mi->max_prob_streams = 1;
356 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
357 mg = &mi->groups[group];
360 mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
361 if (cur_prob_tp < mr->cur_tp &&
362 minstrel_mcs_groups[group].streams <= mi->max_prob_streams) {
363 mi->max_prob_rate = mg->max_prob_rate;
364 cur_prob = mr->cur_prob;
365 cur_prob_tp = mr->cur_tp;
369 #ifdef CONFIG_MAC80211_DEBUGFS
370 /* use fixed index if set */
371 if (mp->fixed_rate_idx != -1) {
372 mi->max_tp_rate = mp->fixed_rate_idx;
373 mi->max_tp_rate2 = mp->fixed_rate_idx;
374 mi->max_prob_rate = mp->fixed_rate_idx;
378 mi->stats_update = jiffies;
382 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
390 if (rate->flags & IEEE80211_TX_RC_MCS)
393 return rate->idx == mp->cck_rates[0] ||
394 rate->idx == mp->cck_rates[1] ||
395 rate->idx == mp->cck_rates[2] ||
396 rate->idx == mp->cck_rates[3];
400 minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
402 struct minstrel_mcs_group_data *mg;
406 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
407 mg = &mi->groups[mi->sample_group];
412 if (++mg->index >= MCS_GROUP_RATES) {
414 if (++mg->column >= ARRAY_SIZE(sample_table))
422 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx,
425 int group, orig_group;
427 orig_group = group = *idx / MCS_GROUP_RATES;
431 if (!mi->groups[group].supported)
434 if (minstrel_mcs_groups[group].streams >
435 minstrel_mcs_groups[orig_group].streams)
439 *idx = mi->groups[group].max_tp_rate;
441 *idx = mi->groups[group].max_tp_rate2;
447 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
449 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
450 struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
453 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
456 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
459 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
460 if (likely(sta->ampdu_mlme.tid_tx[tid]))
463 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
466 ieee80211_start_tx_ba_session(pubsta, tid, 5000);
470 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
471 struct ieee80211_sta *sta, void *priv_sta,
474 struct minstrel_ht_sta_priv *msp = priv_sta;
475 struct minstrel_ht_sta *mi = &msp->ht;
476 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
477 struct ieee80211_tx_rate *ar = info->status.rates;
478 struct minstrel_rate_stats *rate, *rate2;
479 struct minstrel_priv *mp = priv;
480 bool last, update = false;
484 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
486 /* This packet was aggregated but doesn't carry status info */
487 if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
488 !(info->flags & IEEE80211_TX_STAT_AMPDU))
491 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
492 info->status.ampdu_ack_len =
493 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
494 info->status.ampdu_len = 1;
498 mi->ampdu_len += info->status.ampdu_len;
500 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
501 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
502 mi->sample_tries = 1;
506 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
507 mi->sample_packets += info->status.ampdu_len;
509 last = !minstrel_ht_txstat_valid(mp, &ar[0]);
510 for (i = 0; !last; i++) {
511 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
512 !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
514 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
517 rate->success += info->status.ampdu_ack_len;
519 rate->attempts += ar[i].count * info->status.ampdu_len;
523 * check for sudden death of spatial multiplexing,
524 * downgrade to a lower number of streams if necessary.
526 rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
527 if (rate->attempts > 30 &&
528 MINSTREL_FRAC(rate->success, rate->attempts) <
529 MINSTREL_FRAC(20, 100)) {
530 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
534 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
535 if (rate2->attempts > 30 &&
536 MINSTREL_FRAC(rate2->success, rate2->attempts) <
537 MINSTREL_FRAC(20, 100)) {
538 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
542 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
544 minstrel_ht_update_stats(mp, mi);
545 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
546 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
547 minstrel_aggr_check(sta, skb);
551 minstrel_ht_update_rates(mp, mi);
555 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
558 struct minstrel_rate_stats *mr;
559 const struct mcs_group *group;
560 unsigned int tx_time, tx_time_rtscts, tx_time_data;
561 unsigned int cw = mp->cw_min;
562 unsigned int ctime = 0;
563 unsigned int t_slot = 9; /* FIXME */
564 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
565 unsigned int overhead = 0, overhead_rtscts = 0;
567 mr = minstrel_get_ratestats(mi, index);
568 if (mr->probability < MINSTREL_FRAC(1, 10)) {
570 mr->retry_count_rtscts = 1;
575 mr->retry_count_rtscts = 2;
576 mr->retry_updated = true;
578 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
579 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
581 /* Contention time for first 2 tries */
582 ctime = (t_slot * cw) >> 1;
583 cw = min((cw << 1) | 1, mp->cw_max);
584 ctime += (t_slot * cw) >> 1;
585 cw = min((cw << 1) | 1, mp->cw_max);
587 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
588 overhead = mi->overhead;
589 overhead_rtscts = mi->overhead_rtscts;
592 /* Total TX time for data and Contention after first 2 tries */
593 tx_time = ctime + 2 * (overhead + tx_time_data);
594 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
596 /* See how many more tries we can fit inside segment size */
598 /* Contention time for this try */
599 ctime = (t_slot * cw) >> 1;
600 cw = min((cw << 1) | 1, mp->cw_max);
602 /* Total TX time after this try */
603 tx_time += ctime + overhead + tx_time_data;
604 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
606 if (tx_time_rtscts < mp->segment_size)
607 mr->retry_count_rtscts++;
608 } while ((tx_time < mp->segment_size) &&
609 (++mr->retry_count < mp->max_retry));
614 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
615 struct ieee80211_sta_rates *ratetbl, int offset, int index)
617 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
618 struct minstrel_rate_stats *mr;
622 mr = minstrel_get_ratestats(mi, index);
623 if (!mr->retry_updated)
624 minstrel_calc_retransmit(mp, mi, index);
626 if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) {
627 ratetbl->rate[offset].count = 2;
628 ratetbl->rate[offset].count_rts = 2;
629 ratetbl->rate[offset].count_cts = 2;
631 ratetbl->rate[offset].count = mr->retry_count;
632 ratetbl->rate[offset].count_cts = mr->retry_count;
633 ratetbl->rate[offset].count_rts = mr->retry_count_rtscts;
636 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
637 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
640 idx = index % MCS_GROUP_RATES +
641 (group->streams - 1) * MCS_GROUP_RATES;
642 flags = IEEE80211_TX_RC_MCS | group->flags;
646 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
647 flags |= IEEE80211_TX_RC_USE_RTS_CTS;
650 ratetbl->rate[offset].idx = idx;
651 ratetbl->rate[offset].flags = flags;
655 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
657 struct ieee80211_sta_rates *rates;
660 rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
664 /* Start with max_tp_rate */
665 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate);
667 if (mp->hw->max_rates >= 3) {
668 /* At least 3 tx rates supported, use max_tp_rate2 next */
669 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate2);
672 if (mp->hw->max_rates >= 2) {
674 * At least 2 tx rates supported, use max_prob_rate next */
675 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
678 rates->rate[i].idx = -1;
679 rate_control_set_rates(mp->hw, mi->sta, rates);
683 minstrel_get_duration(int index)
685 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
686 return group->duration[index % MCS_GROUP_RATES];
690 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
692 struct minstrel_rate_stats *mr;
693 struct minstrel_mcs_group_data *mg;
694 unsigned int sample_dur, sample_group;
697 if (mi->sample_wait > 0) {
702 if (!mi->sample_tries)
705 mg = &mi->groups[mi->sample_group];
706 sample_idx = sample_table[mg->column][mg->index];
707 mr = &mg->rates[sample_idx];
708 sample_group = mi->sample_group;
709 sample_idx += sample_group * MCS_GROUP_RATES;
710 minstrel_next_sample_idx(mi);
713 * Sampling might add some overhead (RTS, no aggregation)
714 * to the frame. Hence, don't use sampling for the currently
717 if (sample_idx == mi->max_tp_rate ||
718 sample_idx == mi->max_tp_rate2 ||
719 sample_idx == mi->max_prob_rate)
723 * Do not sample if the probability is already higher than 95%
724 * to avoid wasting airtime.
726 if (mr->probability > MINSTREL_FRAC(95, 100))
730 * Make sure that lower rates get sampled only occasionally,
731 * if the link is working perfectly.
733 sample_dur = minstrel_get_duration(sample_idx);
734 if (sample_dur >= minstrel_get_duration(mi->max_tp_rate2) &&
735 (mi->max_prob_streams <
736 minstrel_mcs_groups[sample_group].streams ||
737 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
738 if (mr->sample_skipped < 20)
741 if (mi->sample_slow++ > 2)
750 minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp,
751 struct minstrel_ht_sta *mi, bool val)
753 u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported;
755 if (!supported || !mi->cck_supported_short)
758 if (supported & (mi->cck_supported_short << (val * 4)))
761 supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4);
762 mi->groups[MINSTREL_CCK_GROUP].supported = supported;
766 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
767 struct ieee80211_tx_rate_control *txrc)
769 const struct mcs_group *sample_group;
770 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
771 struct ieee80211_tx_rate *rate = &info->status.rates[0];
772 struct minstrel_ht_sta_priv *msp = priv_sta;
773 struct minstrel_ht_sta *mi = &msp->ht;
774 struct minstrel_priv *mp = priv;
777 if (rate_control_send_low(sta, priv_sta, txrc))
781 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
783 info->flags |= mi->tx_flags;
784 minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble);
786 #ifdef CONFIG_MAC80211_DEBUGFS
787 if (mp->fixed_rate_idx != -1)
791 /* Don't use EAPOL frames for sampling on non-mrr hw */
792 if (mp->hw->max_rates == 1 &&
793 (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
796 sample_idx = minstrel_get_sample_rate(mp, mi);
801 if (mi->total_packets == ~0) {
802 mi->total_packets = 0;
803 mi->sample_packets = 0;
809 sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
810 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
813 if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
814 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
815 rate->idx = mp->cck_rates[idx];
820 rate->idx = sample_idx % MCS_GROUP_RATES +
821 (sample_group->streams - 1) * MCS_GROUP_RATES;
822 rate->flags = IEEE80211_TX_RC_MCS | sample_group->flags;
826 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
827 struct ieee80211_supported_band *sband,
828 struct ieee80211_sta *sta)
832 if (sband->band != IEEE80211_BAND_2GHZ)
835 if (!(mp->hw->flags & IEEE80211_HW_SUPPORTS_HT_CCK_RATES))
838 mi->cck_supported = 0;
839 mi->cck_supported_short = 0;
840 for (i = 0; i < 4; i++) {
841 if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
844 mi->cck_supported |= BIT(i);
845 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
846 mi->cck_supported_short |= BIT(i);
849 mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported;
853 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
854 struct cfg80211_chan_def *chandef,
855 struct ieee80211_sta *sta, void *priv_sta)
857 struct minstrel_priv *mp = priv;
858 struct minstrel_ht_sta_priv *msp = priv_sta;
859 struct minstrel_ht_sta *mi = &msp->ht;
860 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
861 u16 sta_cap = sta->ht_cap.cap;
867 /* fall back to the old minstrel for legacy stations */
868 if (!sta->ht_cap.ht_supported)
871 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
872 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1);
875 memset(mi, 0, sizeof(*mi));
878 mi->stats_update = jiffies;
880 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
881 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
882 mi->overhead += ack_dur;
883 mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
885 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
887 /* When using MRR, sample more on the first attempt, without delay */
889 mi->sample_count = 16;
892 mi->sample_count = 8;
895 mi->sample_tries = 4;
897 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
898 IEEE80211_HT_CAP_RX_STBC_SHIFT;
899 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
901 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
902 mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
904 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
905 mi->groups[i].supported = 0;
906 if (i == MINSTREL_CCK_GROUP) {
907 minstrel_ht_update_cck(mp, mi, sband, sta);
911 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
912 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
913 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
916 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
921 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
922 sta->bandwidth < IEEE80211_STA_RX_BW_40)
925 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
926 if (sta->smps_mode == IEEE80211_SMPS_STATIC &&
927 minstrel_mcs_groups[i].streams > 1)
930 mi->groups[i].supported =
931 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
933 if (mi->groups[i].supported)
940 /* create an initial rate table with the lowest supported rates */
941 minstrel_ht_update_stats(mp, mi);
942 minstrel_ht_update_rates(mp, mi);
948 memset(&msp->legacy, 0, sizeof(msp->legacy));
949 msp->legacy.r = msp->ratelist;
950 msp->legacy.sample_table = msp->sample_table;
951 return mac80211_minstrel.rate_init(priv, sband, chandef, sta,
956 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
957 struct cfg80211_chan_def *chandef,
958 struct ieee80211_sta *sta, void *priv_sta)
960 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
964 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
965 struct cfg80211_chan_def *chandef,
966 struct ieee80211_sta *sta, void *priv_sta,
969 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
973 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
975 struct ieee80211_supported_band *sband;
976 struct minstrel_ht_sta_priv *msp;
977 struct minstrel_priv *mp = priv;
978 struct ieee80211_hw *hw = mp->hw;
982 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
983 sband = hw->wiphy->bands[i];
984 if (sband && sband->n_bitrates > max_rates)
985 max_rates = sband->n_bitrates;
988 msp = kzalloc(sizeof(*msp), gfp);
992 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
996 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
997 if (!msp->sample_table)
1003 kfree(msp->ratelist);
1010 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1012 struct minstrel_ht_sta_priv *msp = priv_sta;
1014 kfree(msp->sample_table);
1015 kfree(msp->ratelist);
1020 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
1022 return mac80211_minstrel.alloc(hw, debugfsdir);
1026 minstrel_ht_free(void *priv)
1028 mac80211_minstrel.free(priv);
1031 static struct rate_control_ops mac80211_minstrel_ht = {
1032 .name = "minstrel_ht",
1033 .tx_status = minstrel_ht_tx_status,
1034 .get_rate = minstrel_ht_get_rate,
1035 .rate_init = minstrel_ht_rate_init,
1036 .rate_update = minstrel_ht_rate_update,
1037 .alloc_sta = minstrel_ht_alloc_sta,
1038 .free_sta = minstrel_ht_free_sta,
1039 .alloc = minstrel_ht_alloc,
1040 .free = minstrel_ht_free,
1041 #ifdef CONFIG_MAC80211_DEBUGFS
1042 .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
1043 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
1049 init_sample_table(void)
1051 int col, i, new_idx;
1052 u8 rnd[MCS_GROUP_RATES];
1054 memset(sample_table, 0xff, sizeof(sample_table));
1055 for (col = 0; col < SAMPLE_COLUMNS; col++) {
1056 for (i = 0; i < MCS_GROUP_RATES; i++) {
1057 get_random_bytes(rnd, sizeof(rnd));
1058 new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1060 while (sample_table[col][new_idx] != 0xff)
1061 new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1063 sample_table[col][new_idx] = i;
1069 rc80211_minstrel_ht_init(void)
1071 init_sample_table();
1072 return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1076 rc80211_minstrel_ht_exit(void)
1078 ieee80211_rate_control_unregister(&mac80211_minstrel_ht);