2 * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
8 #include <linux/netdevice.h>
9 #include <linux/types.h>
10 #include <linux/skbuff.h>
11 #include <linux/debugfs.h>
12 #include <linux/random.h>
13 #include <linux/ieee80211.h>
14 #include <net/mac80211.h>
16 #include "rc80211_minstrel.h"
17 #include "rc80211_minstrel_ht.h"
19 #define AVG_PKT_SIZE 1200
21 /* Number of bits for an average sized packet */
22 #define MCS_NBITS (AVG_PKT_SIZE << 3)
24 /* Number of symbols for a packet with (bps) bits per symbol */
25 #define MCS_NSYMS(bps) DIV_ROUND_UP(MCS_NBITS, (bps))
27 /* Transmission time (nanoseconds) for a packet containing (syms) symbols */
28 #define MCS_SYMBOL_TIME(sgi, syms) \
30 ((syms) * 18000 + 4000) / 5 : /* syms * 3.6 us */ \
31 ((syms) * 1000) << 2 /* syms * 4 us */ \
34 /* Transmit duration for the raw data part of an average sized packet */
35 #define MCS_DURATION(streams, sgi, bps) MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps)))
38 * Define group sort order: HT40 -> SGI -> #streams
40 #define GROUP_IDX(_streams, _sgi, _ht40) \
41 MINSTREL_MAX_STREAMS * 2 * _ht40 + \
42 MINSTREL_MAX_STREAMS * _sgi + \
45 /* MCS rate information for an MCS group */
46 #define MCS_GROUP(_streams, _sgi, _ht40) \
47 [GROUP_IDX(_streams, _sgi, _ht40)] = { \
48 .streams = _streams, \
50 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
51 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
53 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \
54 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \
55 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \
56 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \
57 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \
58 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \
59 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \
60 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \
64 #define CCK_DURATION(_bitrate, _short, _len) \
65 (1000 * (10 /* SIFS */ + \
66 (_short ? 72 + 24 : 144 + 48) + \
67 (8 * (_len + 4) * 10) / (_bitrate)))
69 #define CCK_ACK_DURATION(_bitrate, _short) \
70 (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) + \
71 CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))
73 #define CCK_DURATION_LIST(_short) \
74 CCK_ACK_DURATION(10, _short), \
75 CCK_ACK_DURATION(20, _short), \
76 CCK_ACK_DURATION(55, _short), \
77 CCK_ACK_DURATION(110, _short)
80 [MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS] = { \
83 CCK_DURATION_LIST(false), \
84 CCK_DURATION_LIST(true) \
89 * To enable sufficiently targeted rate sampling, MCS rates are divided into
90 * groups, based on the number of streams and flags (HT40, SGI) that they
93 * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
94 * HT40 -> SGI -> #streams
96 const struct mcs_group minstrel_mcs_groups
[] = {
99 #if MINSTREL_MAX_STREAMS >= 3
105 #if MINSTREL_MAX_STREAMS >= 3
111 #if MINSTREL_MAX_STREAMS >= 3
117 #if MINSTREL_MAX_STREAMS >= 3
125 #define MINSTREL_CCK_GROUP (ARRAY_SIZE(minstrel_mcs_groups) - 1)
127 static u8 sample_table
[SAMPLE_COLUMNS
][MCS_GROUP_RATES
] __read_mostly
;
130 minstrel_ht_update_rates(struct minstrel_priv
*mp
, struct minstrel_ht_sta
*mi
);
133 * Look up an MCS group index based on mac80211 rate information
136 minstrel_ht_get_group_idx(struct ieee80211_tx_rate
*rate
)
138 return GROUP_IDX((rate
->idx
/ 8) + 1,
139 !!(rate
->flags
& IEEE80211_TX_RC_SHORT_GI
),
140 !!(rate
->flags
& IEEE80211_TX_RC_40_MHZ_WIDTH
));
143 static struct minstrel_rate_stats
*
144 minstrel_ht_get_stats(struct minstrel_priv
*mp
, struct minstrel_ht_sta
*mi
,
145 struct ieee80211_tx_rate
*rate
)
149 if (rate
->flags
& IEEE80211_TX_RC_MCS
) {
150 group
= minstrel_ht_get_group_idx(rate
);
153 group
= MINSTREL_CCK_GROUP
;
155 for (idx
= 0; idx
< ARRAY_SIZE(mp
->cck_rates
); idx
++)
156 if (rate
->idx
== mp
->cck_rates
[idx
])
160 if (!(mi
->groups
[group
].supported
& BIT(idx
)))
163 return &mi
->groups
[group
].rates
[idx
];
166 static inline struct minstrel_rate_stats
*
167 minstrel_get_ratestats(struct minstrel_ht_sta
*mi
, int index
)
169 return &mi
->groups
[index
/ MCS_GROUP_RATES
].rates
[index
% MCS_GROUP_RATES
];
174 * Recalculate success probabilities and counters for a rate using EWMA
177 minstrel_calc_rate_ewma(struct minstrel_rate_stats
*mr
)
179 if (unlikely(mr
->attempts
> 0)) {
180 mr
->sample_skipped
= 0;
181 mr
->cur_prob
= MINSTREL_FRAC(mr
->success
, mr
->attempts
);
183 mr
->probability
= mr
->cur_prob
;
185 mr
->probability
= minstrel_ewma(mr
->probability
,
186 mr
->cur_prob
, EWMA_LEVEL
);
187 mr
->att_hist
+= mr
->attempts
;
188 mr
->succ_hist
+= mr
->success
;
190 mr
->sample_skipped
++;
192 mr
->last_success
= mr
->success
;
193 mr
->last_attempts
= mr
->attempts
;
199 * Calculate throughput based on the average A-MPDU length, taking into account
200 * the expected number of retransmissions and their expected length
203 minstrel_ht_calc_tp(struct minstrel_ht_sta
*mi
, int group
, int rate
)
205 struct minstrel_rate_stats
*mr
;
206 unsigned int nsecs
= 0;
210 mr
= &mi
->groups
[group
].rates
[rate
];
211 prob
= mr
->probability
;
213 if (prob
< MINSTREL_FRAC(1, 10)) {
219 * For the throughput calculation, limit the probability value to 90% to
220 * account for collision related packet error rate fluctuation
222 if (prob
> MINSTREL_FRAC(9, 10))
223 prob
= MINSTREL_FRAC(9, 10);
225 if (group
!= MINSTREL_CCK_GROUP
)
226 nsecs
= 1000 * mi
->overhead
/ MINSTREL_TRUNC(mi
->avg_ampdu_len
);
228 nsecs
+= minstrel_mcs_groups
[group
].duration
[rate
];
230 /* prob is scaled - see MINSTREL_FRAC above */
231 tp
= 1000000 * ((prob
* 1000) / nsecs
);
232 mr
->cur_tp
= MINSTREL_TRUNC(tp
);
236 * Update rate statistics and select new primary rates
238 * Rules for rate selection:
239 * - max_prob_rate must use only one stream, as a tradeoff between delivery
240 * probability and throughput during strong fluctuations
241 * - as long as the max prob rate has a probability of more than 3/4, pick
242 * higher throughput rates, even if the probablity is a bit lower
245 minstrel_ht_update_stats(struct minstrel_priv
*mp
, struct minstrel_ht_sta
*mi
)
247 struct minstrel_mcs_group_data
*mg
;
248 struct minstrel_rate_stats
*mr
;
249 int cur_prob
, cur_prob_tp
, cur_tp
, cur_tp2
;
251 bool mi_rates_valid
= false;
253 if (mi
->ampdu_packets
> 0) {
254 mi
->avg_ampdu_len
= minstrel_ewma(mi
->avg_ampdu_len
,
255 MINSTREL_FRAC(mi
->ampdu_len
, mi
->ampdu_packets
), EWMA_LEVEL
);
257 mi
->ampdu_packets
= 0;
261 mi
->sample_count
= 0;
263 for (group
= 0; group
< ARRAY_SIZE(minstrel_mcs_groups
); group
++) {
264 bool mg_rates_valid
= false;
271 mg
= &mi
->groups
[group
];
277 for (i
= 0; i
< MCS_GROUP_RATES
; i
++) {
278 if (!(mg
->supported
& BIT(i
)))
281 index
= MCS_GROUP_RATES
* group
+ i
;
283 /* initialize rates selections starting indexes */
284 if (!mg_rates_valid
) {
285 mg
->max_tp_rate
= mg
->max_tp_rate2
=
286 mg
->max_prob_rate
= i
;
287 if (!mi_rates_valid
) {
288 mi
->max_tp_rate
= mi
->max_tp_rate2
=
289 mi
->max_prob_rate
= index
;
290 mi_rates_valid
= true;
292 mg_rates_valid
= true;
296 mr
->retry_updated
= false;
297 minstrel_calc_rate_ewma(mr
);
298 minstrel_ht_calc_tp(mi
, group
, i
);
303 if ((mr
->cur_tp
> cur_prob_tp
&& mr
->probability
>
304 MINSTREL_FRAC(3, 4)) || mr
->probability
> cur_prob
) {
305 mg
->max_prob_rate
= index
;
306 cur_prob
= mr
->probability
;
307 cur_prob_tp
= mr
->cur_tp
;
310 if (mr
->cur_tp
> cur_tp
) {
311 swap(index
, mg
->max_tp_rate
);
313 mr
= minstrel_get_ratestats(mi
, index
);
316 if (index
>= mg
->max_tp_rate
)
319 if (mr
->cur_tp
> cur_tp2
) {
320 mg
->max_tp_rate2
= index
;
321 cur_tp2
= mr
->cur_tp
;
326 /* try to sample all available rates during each interval */
327 mi
->sample_count
*= 8;
333 for (group
= 0; group
< ARRAY_SIZE(minstrel_mcs_groups
); group
++) {
334 mg
= &mi
->groups
[group
];
338 mr
= minstrel_get_ratestats(mi
, mg
->max_tp_rate
);
339 if (cur_tp
< mr
->cur_tp
) {
340 mi
->max_tp_rate2
= mi
->max_tp_rate
;
342 mi
->max_tp_rate
= mg
->max_tp_rate
;
344 mi
->max_prob_streams
= minstrel_mcs_groups
[group
].streams
- 1;
347 mr
= minstrel_get_ratestats(mi
, mg
->max_tp_rate2
);
348 if (cur_tp2
< mr
->cur_tp
) {
349 mi
->max_tp_rate2
= mg
->max_tp_rate2
;
350 cur_tp2
= mr
->cur_tp
;
354 if (mi
->max_prob_streams
< 1)
355 mi
->max_prob_streams
= 1;
357 for (group
= 0; group
< ARRAY_SIZE(minstrel_mcs_groups
); group
++) {
358 mg
= &mi
->groups
[group
];
361 mr
= minstrel_get_ratestats(mi
, mg
->max_prob_rate
);
362 if (cur_prob_tp
< mr
->cur_tp
&&
363 minstrel_mcs_groups
[group
].streams
<= mi
->max_prob_streams
) {
364 mi
->max_prob_rate
= mg
->max_prob_rate
;
365 cur_prob
= mr
->cur_prob
;
366 cur_prob_tp
= mr
->cur_tp
;
370 #ifdef CONFIG_MAC80211_DEBUGFS
371 /* use fixed index if set */
372 if (mp
->fixed_rate_idx
!= -1) {
373 mi
->max_tp_rate
= mp
->fixed_rate_idx
;
374 mi
->max_tp_rate2
= mp
->fixed_rate_idx
;
375 mi
->max_prob_rate
= mp
->fixed_rate_idx
;
379 mi
->stats_update
= jiffies
;
383 minstrel_ht_txstat_valid(struct minstrel_priv
*mp
, struct ieee80211_tx_rate
*rate
)
391 if (rate
->flags
& IEEE80211_TX_RC_MCS
)
394 return rate
->idx
== mp
->cck_rates
[0] ||
395 rate
->idx
== mp
->cck_rates
[1] ||
396 rate
->idx
== mp
->cck_rates
[2] ||
397 rate
->idx
== mp
->cck_rates
[3];
401 minstrel_next_sample_idx(struct minstrel_ht_sta
*mi
)
403 struct minstrel_mcs_group_data
*mg
;
407 mi
->sample_group
%= ARRAY_SIZE(minstrel_mcs_groups
);
408 mg
= &mi
->groups
[mi
->sample_group
];
413 if (++mg
->index
>= MCS_GROUP_RATES
) {
415 if (++mg
->column
>= ARRAY_SIZE(sample_table
))
423 minstrel_downgrade_rate(struct minstrel_ht_sta
*mi
, unsigned int *idx
,
426 int group
, orig_group
;
428 orig_group
= group
= *idx
/ MCS_GROUP_RATES
;
432 if (!mi
->groups
[group
].supported
)
435 if (minstrel_mcs_groups
[group
].streams
>
436 minstrel_mcs_groups
[orig_group
].streams
)
440 *idx
= mi
->groups
[group
].max_tp_rate
;
442 *idx
= mi
->groups
[group
].max_tp_rate2
;
448 minstrel_aggr_check(struct ieee80211_sta
*pubsta
, struct sk_buff
*skb
)
450 struct ieee80211_hdr
*hdr
= (struct ieee80211_hdr
*) skb
->data
;
451 struct sta_info
*sta
= container_of(pubsta
, struct sta_info
, sta
);
454 if (unlikely(!ieee80211_is_data_qos(hdr
->frame_control
)))
457 if (unlikely(skb
->protocol
== cpu_to_be16(ETH_P_PAE
)))
460 tid
= *ieee80211_get_qos_ctl(hdr
) & IEEE80211_QOS_CTL_TID_MASK
;
461 if (likely(sta
->ampdu_mlme
.tid_tx
[tid
]))
464 if (skb_get_queue_mapping(skb
) == IEEE80211_AC_VO
)
467 ieee80211_start_tx_ba_session(pubsta
, tid
, 5000);
471 minstrel_ht_tx_status(void *priv
, struct ieee80211_supported_band
*sband
,
472 struct ieee80211_sta
*sta
, void *priv_sta
,
475 struct minstrel_ht_sta_priv
*msp
= priv_sta
;
476 struct minstrel_ht_sta
*mi
= &msp
->ht
;
477 struct ieee80211_tx_info
*info
= IEEE80211_SKB_CB(skb
);
478 struct ieee80211_tx_rate
*ar
= info
->status
.rates
;
479 struct minstrel_rate_stats
*rate
, *rate2
;
480 struct minstrel_priv
*mp
= priv
;
481 bool last
, update
= false;
485 return mac80211_minstrel
.tx_status(priv
, sband
, sta
, &msp
->legacy
, skb
);
487 /* This packet was aggregated but doesn't carry status info */
488 if ((info
->flags
& IEEE80211_TX_CTL_AMPDU
) &&
489 !(info
->flags
& IEEE80211_TX_STAT_AMPDU
))
492 if (!(info
->flags
& IEEE80211_TX_STAT_AMPDU
)) {
493 info
->status
.ampdu_ack_len
=
494 (info
->flags
& IEEE80211_TX_STAT_ACK
? 1 : 0);
495 info
->status
.ampdu_len
= 1;
499 mi
->ampdu_len
+= info
->status
.ampdu_len
;
501 if (!mi
->sample_wait
&& !mi
->sample_tries
&& mi
->sample_count
> 0) {
502 mi
->sample_wait
= 16 + 2 * MINSTREL_TRUNC(mi
->avg_ampdu_len
);
503 mi
->sample_tries
= 1;
507 if (info
->flags
& IEEE80211_TX_CTL_RATE_CTRL_PROBE
)
508 mi
->sample_packets
+= info
->status
.ampdu_len
;
510 last
= !minstrel_ht_txstat_valid(mp
, &ar
[0]);
511 for (i
= 0; !last
; i
++) {
512 last
= (i
== IEEE80211_TX_MAX_RATES
- 1) ||
513 !minstrel_ht_txstat_valid(mp
, &ar
[i
+ 1]);
515 rate
= minstrel_ht_get_stats(mp
, mi
, &ar
[i
]);
518 rate
->success
+= info
->status
.ampdu_ack_len
;
520 rate
->attempts
+= ar
[i
].count
* info
->status
.ampdu_len
;
524 * check for sudden death of spatial multiplexing,
525 * downgrade to a lower number of streams if necessary.
527 rate
= minstrel_get_ratestats(mi
, mi
->max_tp_rate
);
528 if (rate
->attempts
> 30 &&
529 MINSTREL_FRAC(rate
->success
, rate
->attempts
) <
530 MINSTREL_FRAC(20, 100)) {
531 minstrel_downgrade_rate(mi
, &mi
->max_tp_rate
, true);
535 rate2
= minstrel_get_ratestats(mi
, mi
->max_tp_rate2
);
536 if (rate2
->attempts
> 30 &&
537 MINSTREL_FRAC(rate2
->success
, rate2
->attempts
) <
538 MINSTREL_FRAC(20, 100)) {
539 minstrel_downgrade_rate(mi
, &mi
->max_tp_rate2
, false);
543 if (time_after(jiffies
, mi
->stats_update
+ (mp
->update_interval
/ 2 * HZ
) / 1000)) {
545 minstrel_ht_update_stats(mp
, mi
);
546 if (!(info
->flags
& IEEE80211_TX_CTL_AMPDU
) &&
547 mi
->max_prob_rate
/ MCS_GROUP_RATES
!= MINSTREL_CCK_GROUP
)
548 minstrel_aggr_check(sta
, skb
);
552 minstrel_ht_update_rates(mp
, mi
);
556 minstrel_calc_retransmit(struct minstrel_priv
*mp
, struct minstrel_ht_sta
*mi
,
559 struct minstrel_rate_stats
*mr
;
560 const struct mcs_group
*group
;
561 unsigned int tx_time
, tx_time_rtscts
, tx_time_data
;
562 unsigned int cw
= mp
->cw_min
;
563 unsigned int ctime
= 0;
564 unsigned int t_slot
= 9; /* FIXME */
565 unsigned int ampdu_len
= MINSTREL_TRUNC(mi
->avg_ampdu_len
);
566 unsigned int overhead
= 0, overhead_rtscts
= 0;
568 mr
= minstrel_get_ratestats(mi
, index
);
569 if (mr
->probability
< MINSTREL_FRAC(1, 10)) {
571 mr
->retry_count_rtscts
= 1;
576 mr
->retry_count_rtscts
= 2;
577 mr
->retry_updated
= true;
579 group
= &minstrel_mcs_groups
[index
/ MCS_GROUP_RATES
];
580 tx_time_data
= group
->duration
[index
% MCS_GROUP_RATES
] * ampdu_len
/ 1000;
582 /* Contention time for first 2 tries */
583 ctime
= (t_slot
* cw
) >> 1;
584 cw
= min((cw
<< 1) | 1, mp
->cw_max
);
585 ctime
+= (t_slot
* cw
) >> 1;
586 cw
= min((cw
<< 1) | 1, mp
->cw_max
);
588 if (index
/ MCS_GROUP_RATES
!= MINSTREL_CCK_GROUP
) {
589 overhead
= mi
->overhead
;
590 overhead_rtscts
= mi
->overhead_rtscts
;
593 /* Total TX time for data and Contention after first 2 tries */
594 tx_time
= ctime
+ 2 * (overhead
+ tx_time_data
);
595 tx_time_rtscts
= ctime
+ 2 * (overhead_rtscts
+ tx_time_data
);
597 /* See how many more tries we can fit inside segment size */
599 /* Contention time for this try */
600 ctime
= (t_slot
* cw
) >> 1;
601 cw
= min((cw
<< 1) | 1, mp
->cw_max
);
603 /* Total TX time after this try */
604 tx_time
+= ctime
+ overhead
+ tx_time_data
;
605 tx_time_rtscts
+= ctime
+ overhead_rtscts
+ tx_time_data
;
607 if (tx_time_rtscts
< mp
->segment_size
)
608 mr
->retry_count_rtscts
++;
609 } while ((tx_time
< mp
->segment_size
) &&
610 (++mr
->retry_count
< mp
->max_retry
));
615 minstrel_ht_set_rate(struct minstrel_priv
*mp
, struct minstrel_ht_sta
*mi
,
616 struct ieee80211_sta_rates
*ratetbl
, int offset
, int index
)
618 const struct mcs_group
*group
= &minstrel_mcs_groups
[index
/ MCS_GROUP_RATES
];
619 struct minstrel_rate_stats
*mr
;
623 mr
= minstrel_get_ratestats(mi
, index
);
624 if (!mr
->retry_updated
)
625 minstrel_calc_retransmit(mp
, mi
, index
);
627 if (mr
->probability
< MINSTREL_FRAC(20, 100) || !mr
->retry_count
) {
628 ratetbl
->rate
[offset
].count
= 2;
629 ratetbl
->rate
[offset
].count_rts
= 2;
630 ratetbl
->rate
[offset
].count_cts
= 2;
632 ratetbl
->rate
[offset
].count
= mr
->retry_count
;
633 ratetbl
->rate
[offset
].count_cts
= mr
->retry_count
;
634 ratetbl
->rate
[offset
].count_rts
= mr
->retry_count_rtscts
;
637 if (index
/ MCS_GROUP_RATES
== MINSTREL_CCK_GROUP
) {
638 idx
= mp
->cck_rates
[index
% ARRAY_SIZE(mp
->cck_rates
)];
641 idx
= index
% MCS_GROUP_RATES
+ (group
->streams
- 1) * 8;
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 sample_group
= mi
->sample_group
;
706 mg
= &mi
->groups
[sample_group
];
707 sample_idx
= sample_table
[mg
->column
][mg
->index
];
708 minstrel_next_sample_idx(mi
);
710 if (!(mg
->supported
& BIT(sample_idx
)))
713 mr
= &mg
->rates
[sample_idx
];
714 sample_idx
+= sample_group
* MCS_GROUP_RATES
;
717 * Sampling might add some overhead (RTS, no aggregation)
718 * to the frame. Hence, don't use sampling for the currently
721 if (sample_idx
== mi
->max_tp_rate
||
722 sample_idx
== mi
->max_tp_rate2
||
723 sample_idx
== mi
->max_prob_rate
)
727 * Do not sample if the probability is already higher than 95%
728 * to avoid wasting airtime.
730 if (mr
->probability
> MINSTREL_FRAC(95, 100))
734 * Make sure that lower rates get sampled only occasionally,
735 * if the link is working perfectly.
737 sample_dur
= minstrel_get_duration(sample_idx
);
738 if (sample_dur
>= minstrel_get_duration(mi
->max_tp_rate2
) &&
739 (mi
->max_prob_streams
<
740 minstrel_mcs_groups
[sample_group
].streams
||
741 sample_dur
>= minstrel_get_duration(mi
->max_prob_rate
))) {
742 if (mr
->sample_skipped
< 20)
745 if (mi
->sample_slow
++ > 2)
754 minstrel_ht_check_cck_shortpreamble(struct minstrel_priv
*mp
,
755 struct minstrel_ht_sta
*mi
, bool val
)
757 u8 supported
= mi
->groups
[MINSTREL_CCK_GROUP
].supported
;
759 if (!supported
|| !mi
->cck_supported_short
)
762 if (supported
& (mi
->cck_supported_short
<< (val
* 4)))
765 supported
^= mi
->cck_supported_short
| (mi
->cck_supported_short
<< 4);
766 mi
->groups
[MINSTREL_CCK_GROUP
].supported
= supported
;
770 minstrel_ht_get_rate(void *priv
, struct ieee80211_sta
*sta
, void *priv_sta
,
771 struct ieee80211_tx_rate_control
*txrc
)
773 const struct mcs_group
*sample_group
;
774 struct ieee80211_tx_info
*info
= IEEE80211_SKB_CB(txrc
->skb
);
775 struct ieee80211_tx_rate
*rate
= &info
->status
.rates
[0];
776 struct minstrel_ht_sta_priv
*msp
= priv_sta
;
777 struct minstrel_ht_sta
*mi
= &msp
->ht
;
778 struct minstrel_priv
*mp
= priv
;
781 if (rate_control_send_low(sta
, priv_sta
, txrc
))
785 return mac80211_minstrel
.get_rate(priv
, sta
, &msp
->legacy
, txrc
);
787 info
->flags
|= mi
->tx_flags
;
788 minstrel_ht_check_cck_shortpreamble(mp
, mi
, txrc
->short_preamble
);
790 #ifdef CONFIG_MAC80211_DEBUGFS
791 if (mp
->fixed_rate_idx
!= -1)
795 /* Don't use EAPOL frames for sampling on non-mrr hw */
796 if (mp
->hw
->max_rates
== 1 &&
797 (info
->control
.flags
& IEEE80211_TX_CTRL_PORT_CTRL_PROTO
))
800 sample_idx
= minstrel_get_sample_rate(mp
, mi
);
805 if (mi
->total_packets
== ~0) {
806 mi
->total_packets
= 0;
807 mi
->sample_packets
= 0;
813 sample_group
= &minstrel_mcs_groups
[sample_idx
/ MCS_GROUP_RATES
];
814 info
->flags
|= IEEE80211_TX_CTL_RATE_CTRL_PROBE
;
817 if (sample_idx
/ MCS_GROUP_RATES
== MINSTREL_CCK_GROUP
) {
818 int idx
= sample_idx
% ARRAY_SIZE(mp
->cck_rates
);
819 rate
->idx
= mp
->cck_rates
[idx
];
824 rate
->idx
= sample_idx
% MCS_GROUP_RATES
+
825 (sample_group
->streams
- 1) * 8;
826 rate
->flags
= IEEE80211_TX_RC_MCS
| sample_group
->flags
;
830 minstrel_ht_update_cck(struct minstrel_priv
*mp
, struct minstrel_ht_sta
*mi
,
831 struct ieee80211_supported_band
*sband
,
832 struct ieee80211_sta
*sta
)
836 if (sband
->band
!= IEEE80211_BAND_2GHZ
)
839 if (!(mp
->hw
->flags
& IEEE80211_HW_SUPPORTS_HT_CCK_RATES
))
842 mi
->cck_supported
= 0;
843 mi
->cck_supported_short
= 0;
844 for (i
= 0; i
< 4; i
++) {
845 if (!rate_supported(sta
, sband
->band
, mp
->cck_rates
[i
]))
848 mi
->cck_supported
|= BIT(i
);
849 if (sband
->bitrates
[i
].flags
& IEEE80211_RATE_SHORT_PREAMBLE
)
850 mi
->cck_supported_short
|= BIT(i
);
853 mi
->groups
[MINSTREL_CCK_GROUP
].supported
= mi
->cck_supported
;
857 minstrel_ht_update_caps(void *priv
, struct ieee80211_supported_band
*sband
,
858 struct cfg80211_chan_def
*chandef
,
859 struct ieee80211_sta
*sta
, void *priv_sta
)
861 struct minstrel_priv
*mp
= priv
;
862 struct minstrel_ht_sta_priv
*msp
= priv_sta
;
863 struct minstrel_ht_sta
*mi
= &msp
->ht
;
864 struct ieee80211_mcs_info
*mcs
= &sta
->ht_cap
.mcs
;
865 u16 sta_cap
= sta
->ht_cap
.cap
;
871 /* fall back to the old minstrel for legacy stations */
872 if (!sta
->ht_cap
.ht_supported
)
875 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups
) !=
876 MINSTREL_MAX_STREAMS
* MINSTREL_STREAM_GROUPS
+ 1);
879 memset(mi
, 0, sizeof(*mi
));
882 mi
->stats_update
= jiffies
;
884 ack_dur
= ieee80211_frame_duration(sband
->band
, 10, 60, 1, 1, 0);
885 mi
->overhead
= ieee80211_frame_duration(sband
->band
, 0, 60, 1, 1, 0);
886 mi
->overhead
+= ack_dur
;
887 mi
->overhead_rtscts
= mi
->overhead
+ 2 * ack_dur
;
889 mi
->avg_ampdu_len
= MINSTREL_FRAC(1, 1);
891 /* When using MRR, sample more on the first attempt, without delay */
893 mi
->sample_count
= 16;
896 mi
->sample_count
= 8;
899 mi
->sample_tries
= 4;
901 stbc
= (sta_cap
& IEEE80211_HT_CAP_RX_STBC
) >>
902 IEEE80211_HT_CAP_RX_STBC_SHIFT
;
903 mi
->tx_flags
|= stbc
<< IEEE80211_TX_CTL_STBC_SHIFT
;
905 if (sta_cap
& IEEE80211_HT_CAP_LDPC_CODING
)
906 mi
->tx_flags
|= IEEE80211_TX_CTL_LDPC
;
908 for (i
= 0; i
< ARRAY_SIZE(mi
->groups
); i
++) {
909 mi
->groups
[i
].supported
= 0;
910 if (i
== MINSTREL_CCK_GROUP
) {
911 minstrel_ht_update_cck(mp
, mi
, sband
, sta
);
915 if (minstrel_mcs_groups
[i
].flags
& IEEE80211_TX_RC_SHORT_GI
) {
916 if (minstrel_mcs_groups
[i
].flags
& IEEE80211_TX_RC_40_MHZ_WIDTH
) {
917 if (!(sta_cap
& IEEE80211_HT_CAP_SGI_40
))
920 if (!(sta_cap
& IEEE80211_HT_CAP_SGI_20
))
925 if (minstrel_mcs_groups
[i
].flags
& IEEE80211_TX_RC_40_MHZ_WIDTH
&&
926 sta
->bandwidth
< IEEE80211_STA_RX_BW_40
)
929 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
930 if (sta
->smps_mode
== IEEE80211_SMPS_STATIC
&&
931 minstrel_mcs_groups
[i
].streams
> 1)
934 mi
->groups
[i
].supported
=
935 mcs
->rx_mask
[minstrel_mcs_groups
[i
].streams
- 1];
937 if (mi
->groups
[i
].supported
)
944 /* create an initial rate table with the lowest supported rates */
945 minstrel_ht_update_stats(mp
, mi
);
946 minstrel_ht_update_rates(mp
, mi
);
952 memset(&msp
->legacy
, 0, sizeof(msp
->legacy
));
953 msp
->legacy
.r
= msp
->ratelist
;
954 msp
->legacy
.sample_table
= msp
->sample_table
;
955 return mac80211_minstrel
.rate_init(priv
, sband
, chandef
, sta
,
960 minstrel_ht_rate_init(void *priv
, struct ieee80211_supported_band
*sband
,
961 struct cfg80211_chan_def
*chandef
,
962 struct ieee80211_sta
*sta
, void *priv_sta
)
964 minstrel_ht_update_caps(priv
, sband
, chandef
, sta
, priv_sta
);
968 minstrel_ht_rate_update(void *priv
, struct ieee80211_supported_band
*sband
,
969 struct cfg80211_chan_def
*chandef
,
970 struct ieee80211_sta
*sta
, void *priv_sta
,
973 minstrel_ht_update_caps(priv
, sband
, chandef
, sta
, priv_sta
);
977 minstrel_ht_alloc_sta(void *priv
, struct ieee80211_sta
*sta
, gfp_t gfp
)
979 struct ieee80211_supported_band
*sband
;
980 struct minstrel_ht_sta_priv
*msp
;
981 struct minstrel_priv
*mp
= priv
;
982 struct ieee80211_hw
*hw
= mp
->hw
;
986 for (i
= 0; i
< IEEE80211_NUM_BANDS
; i
++) {
987 sband
= hw
->wiphy
->bands
[i
];
988 if (sband
&& sband
->n_bitrates
> max_rates
)
989 max_rates
= sband
->n_bitrates
;
992 msp
= kzalloc(sizeof(*msp
), gfp
);
996 msp
->ratelist
= kzalloc(sizeof(struct minstrel_rate
) * max_rates
, gfp
);
1000 msp
->sample_table
= kmalloc(SAMPLE_COLUMNS
* max_rates
, gfp
);
1001 if (!msp
->sample_table
)
1007 kfree(msp
->ratelist
);
1014 minstrel_ht_free_sta(void *priv
, struct ieee80211_sta
*sta
, void *priv_sta
)
1016 struct minstrel_ht_sta_priv
*msp
= priv_sta
;
1018 kfree(msp
->sample_table
);
1019 kfree(msp
->ratelist
);
1024 minstrel_ht_alloc(struct ieee80211_hw
*hw
, struct dentry
*debugfsdir
)
1026 return mac80211_minstrel
.alloc(hw
, debugfsdir
);
1030 minstrel_ht_free(void *priv
)
1032 mac80211_minstrel
.free(priv
);
1035 static u32
minstrel_ht_get_expected_throughput(void *priv_sta
)
1037 struct minstrel_ht_sta_priv
*msp
= priv_sta
;
1038 struct minstrel_ht_sta
*mi
= &msp
->ht
;
1042 return mac80211_minstrel
.get_expected_throughput(priv_sta
);
1044 i
= mi
->max_tp_rate
/ MCS_GROUP_RATES
;
1045 j
= mi
->max_tp_rate
% MCS_GROUP_RATES
;
1047 /* convert cur_tp from pkt per second in kbps */
1048 return mi
->groups
[i
].rates
[j
].cur_tp
* AVG_PKT_SIZE
* 8 / 1024;
1051 static const struct rate_control_ops mac80211_minstrel_ht
= {
1052 .name
= "minstrel_ht",
1053 .tx_status
= minstrel_ht_tx_status
,
1054 .get_rate
= minstrel_ht_get_rate
,
1055 .rate_init
= minstrel_ht_rate_init
,
1056 .rate_update
= minstrel_ht_rate_update
,
1057 .alloc_sta
= minstrel_ht_alloc_sta
,
1058 .free_sta
= minstrel_ht_free_sta
,
1059 .alloc
= minstrel_ht_alloc
,
1060 .free
= minstrel_ht_free
,
1061 #ifdef CONFIG_MAC80211_DEBUGFS
1062 .add_sta_debugfs
= minstrel_ht_add_sta_debugfs
,
1063 .remove_sta_debugfs
= minstrel_ht_remove_sta_debugfs
,
1065 .get_expected_throughput
= minstrel_ht_get_expected_throughput
,
1069 static void __init
init_sample_table(void)
1071 int col
, i
, new_idx
;
1072 u8 rnd
[MCS_GROUP_RATES
];
1074 memset(sample_table
, 0xff, sizeof(sample_table
));
1075 for (col
= 0; col
< SAMPLE_COLUMNS
; col
++) {
1076 prandom_bytes(rnd
, sizeof(rnd
));
1077 for (i
= 0; i
< MCS_GROUP_RATES
; i
++) {
1078 new_idx
= (i
+ rnd
[i
]) % MCS_GROUP_RATES
;
1079 while (sample_table
[col
][new_idx
] != 0xff)
1080 new_idx
= (new_idx
+ 1) % MCS_GROUP_RATES
;
1082 sample_table
[col
][new_idx
] = i
;
1088 rc80211_minstrel_ht_init(void)
1090 init_sample_table();
1091 return ieee80211_rate_control_register(&mac80211_minstrel_ht
);
1095 rc80211_minstrel_ht_exit(void)
1097 ieee80211_rate_control_unregister(&mac80211_minstrel_ht
);