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ec8aa669 FF |
1 | /* |
2 | * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org> | |
3 | * | |
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. | |
7 | */ | |
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> | |
15 | #include "rate.h" | |
16 | #include "rc80211_minstrel.h" | |
17 | #include "rc80211_minstrel_ht.h" | |
18 | ||
19 | #define AVG_PKT_SIZE 1200 | |
20 | #define SAMPLE_COLUMNS 10 | |
21 | #define EWMA_LEVEL 75 | |
22 | ||
23 | /* Number of bits for an average sized packet */ | |
24 | #define MCS_NBITS (AVG_PKT_SIZE << 3) | |
25 | ||
26 | /* Number of symbols for a packet with (bps) bits per symbol */ | |
27 | #define MCS_NSYMS(bps) ((MCS_NBITS + (bps) - 1) / (bps)) | |
28 | ||
29 | /* Transmission time for a packet containing (syms) symbols */ | |
30 | #define MCS_SYMBOL_TIME(sgi, syms) \ | |
31 | (sgi ? \ | |
32 | ((syms) * 18 + 4) / 5 : /* syms * 3.6 us */ \ | |
33 | (syms) << 2 /* syms * 4 us */ \ | |
34 | ) | |
35 | ||
36 | /* Transmit duration for the raw data part of an average sized packet */ | |
37 | #define MCS_DURATION(streams, sgi, bps) MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps))) | |
38 | ||
39 | /* MCS rate information for an MCS group */ | |
40 | #define MCS_GROUP(_streams, _sgi, _ht40) { \ | |
41 | .streams = _streams, \ | |
42 | .flags = \ | |
43 | (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \ | |
44 | (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \ | |
45 | .duration = { \ | |
46 | MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \ | |
47 | MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \ | |
48 | MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \ | |
49 | MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \ | |
50 | MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \ | |
51 | MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \ | |
52 | MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \ | |
53 | MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \ | |
54 | } \ | |
55 | } | |
56 | ||
57 | /* | |
58 | * To enable sufficiently targeted rate sampling, MCS rates are divided into | |
59 | * groups, based on the number of streams and flags (HT40, SGI) that they | |
60 | * use. | |
61 | */ | |
62 | const struct mcs_group minstrel_mcs_groups[] = { | |
63 | MCS_GROUP(1, 0, 0), | |
64 | MCS_GROUP(2, 0, 0), | |
65 | #if MINSTREL_MAX_STREAMS >= 3 | |
66 | MCS_GROUP(3, 0, 0), | |
67 | #endif | |
68 | ||
69 | MCS_GROUP(1, 1, 0), | |
70 | MCS_GROUP(2, 1, 0), | |
71 | #if MINSTREL_MAX_STREAMS >= 3 | |
72 | MCS_GROUP(3, 1, 0), | |
73 | #endif | |
74 | ||
75 | MCS_GROUP(1, 0, 1), | |
76 | MCS_GROUP(2, 0, 1), | |
77 | #if MINSTREL_MAX_STREAMS >= 3 | |
78 | MCS_GROUP(3, 0, 1), | |
79 | #endif | |
80 | ||
81 | MCS_GROUP(1, 1, 1), | |
82 | MCS_GROUP(2, 1, 1), | |
83 | #if MINSTREL_MAX_STREAMS >= 3 | |
84 | MCS_GROUP(3, 1, 1), | |
85 | #endif | |
86 | }; | |
87 | ||
88 | static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES]; | |
89 | ||
90 | /* | |
91 | * Perform EWMA (Exponentially Weighted Moving Average) calculation | |
92 | */ | |
93 | static int | |
94 | minstrel_ewma(int old, int new, int weight) | |
95 | { | |
96 | return (new * (100 - weight) + old * weight) / 100; | |
97 | } | |
98 | ||
99 | /* | |
100 | * Look up an MCS group index based on mac80211 rate information | |
101 | */ | |
102 | static int | |
103 | minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate) | |
104 | { | |
105 | int streams = (rate->idx / MCS_GROUP_RATES) + 1; | |
106 | u32 flags = IEEE80211_TX_RC_SHORT_GI | IEEE80211_TX_RC_40_MHZ_WIDTH; | |
107 | int i; | |
108 | ||
109 | for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) { | |
110 | if (minstrel_mcs_groups[i].streams != streams) | |
111 | continue; | |
112 | if (minstrel_mcs_groups[i].flags != (rate->flags & flags)) | |
113 | continue; | |
114 | ||
115 | return i; | |
116 | } | |
117 | ||
118 | WARN_ON(1); | |
119 | return 0; | |
120 | } | |
121 | ||
122 | static inline struct minstrel_rate_stats * | |
123 | minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index) | |
124 | { | |
125 | return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES]; | |
126 | } | |
127 | ||
128 | ||
129 | /* | |
130 | * Recalculate success probabilities and counters for a rate using EWMA | |
131 | */ | |
132 | static void | |
133 | minstrel_calc_rate_ewma(struct minstrel_priv *mp, struct minstrel_rate_stats *mr) | |
134 | { | |
135 | if (unlikely(mr->attempts > 0)) { | |
136 | mr->sample_skipped = 0; | |
137 | mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts); | |
138 | if (!mr->att_hist) | |
139 | mr->probability = mr->cur_prob; | |
140 | else | |
141 | mr->probability = minstrel_ewma(mr->probability, | |
142 | mr->cur_prob, EWMA_LEVEL); | |
143 | mr->att_hist += mr->attempts; | |
144 | mr->succ_hist += mr->success; | |
145 | } else { | |
146 | mr->sample_skipped++; | |
147 | } | |
148 | mr->last_success = mr->success; | |
149 | mr->last_attempts = mr->attempts; | |
150 | mr->success = 0; | |
151 | mr->attempts = 0; | |
152 | } | |
153 | ||
154 | /* | |
155 | * Calculate throughput based on the average A-MPDU length, taking into account | |
156 | * the expected number of retransmissions and their expected length | |
157 | */ | |
158 | static void | |
159 | minstrel_ht_calc_tp(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, | |
160 | int group, int rate) | |
161 | { | |
162 | struct minstrel_rate_stats *mr; | |
163 | unsigned int usecs; | |
164 | ||
165 | mr = &mi->groups[group].rates[rate]; | |
166 | ||
167 | if (mr->probability < MINSTREL_FRAC(1, 10)) { | |
168 | mr->cur_tp = 0; | |
169 | return; | |
170 | } | |
171 | ||
172 | usecs = mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len); | |
173 | usecs += minstrel_mcs_groups[group].duration[rate]; | |
174 | mr->cur_tp = MINSTREL_TRUNC((1000000 / usecs) * mr->probability); | |
175 | } | |
176 | ||
177 | /* | |
178 | * Update rate statistics and select new primary rates | |
179 | * | |
180 | * Rules for rate selection: | |
181 | * - max_prob_rate must use only one stream, as a tradeoff between delivery | |
182 | * probability and throughput during strong fluctuations | |
183 | * - as long as the max prob rate has a probability of more than 3/4, pick | |
184 | * higher throughput rates, even if the probablity is a bit lower | |
185 | */ | |
186 | static void | |
187 | minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) | |
188 | { | |
189 | struct minstrel_mcs_group_data *mg; | |
190 | struct minstrel_rate_stats *mr; | |
191 | int cur_prob, cur_prob_tp, cur_tp, cur_tp2; | |
192 | int group, i, index; | |
193 | ||
194 | if (mi->ampdu_packets > 0) { | |
195 | mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len, | |
196 | MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL); | |
197 | mi->ampdu_len = 0; | |
198 | mi->ampdu_packets = 0; | |
199 | } | |
200 | ||
201 | mi->sample_slow = 0; | |
202 | mi->sample_count = 0; | |
203 | mi->max_tp_rate = 0; | |
204 | mi->max_tp_rate2 = 0; | |
205 | mi->max_prob_rate = 0; | |
206 | ||
207 | for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { | |
208 | cur_prob = 0; | |
209 | cur_prob_tp = 0; | |
210 | cur_tp = 0; | |
211 | cur_tp2 = 0; | |
212 | ||
213 | mg = &mi->groups[group]; | |
214 | if (!mg->supported) | |
215 | continue; | |
216 | ||
217 | mg->max_tp_rate = 0; | |
218 | mg->max_tp_rate2 = 0; | |
219 | mg->max_prob_rate = 0; | |
220 | mi->sample_count++; | |
221 | ||
222 | for (i = 0; i < MCS_GROUP_RATES; i++) { | |
223 | if (!(mg->supported & BIT(i))) | |
224 | continue; | |
225 | ||
226 | mr = &mg->rates[i]; | |
227 | mr->retry_updated = false; | |
228 | index = MCS_GROUP_RATES * group + i; | |
229 | minstrel_calc_rate_ewma(mp, mr); | |
230 | minstrel_ht_calc_tp(mp, mi, group, i); | |
231 | ||
232 | if (!mr->cur_tp) | |
233 | continue; | |
234 | ||
235 | /* ignore the lowest rate of each single-stream group */ | |
236 | if (!i && minstrel_mcs_groups[group].streams == 1) | |
237 | continue; | |
238 | ||
239 | if ((mr->cur_tp > cur_prob_tp && mr->probability > | |
240 | MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) { | |
241 | mg->max_prob_rate = index; | |
242 | cur_prob = mr->probability; | |
009271f9 | 243 | cur_prob_tp = mr->cur_tp; |
ec8aa669 FF |
244 | } |
245 | ||
246 | if (mr->cur_tp > cur_tp) { | |
247 | swap(index, mg->max_tp_rate); | |
248 | cur_tp = mr->cur_tp; | |
249 | mr = minstrel_get_ratestats(mi, index); | |
250 | } | |
251 | ||
252 | if (index >= mg->max_tp_rate) | |
253 | continue; | |
254 | ||
255 | if (mr->cur_tp > cur_tp2) { | |
256 | mg->max_tp_rate2 = index; | |
257 | cur_tp2 = mr->cur_tp; | |
258 | } | |
259 | } | |
260 | } | |
261 | ||
262 | /* try to sample up to half of the availble rates during each interval */ | |
263 | mi->sample_count *= 4; | |
264 | ||
265 | cur_prob = 0; | |
266 | cur_prob_tp = 0; | |
267 | cur_tp = 0; | |
268 | cur_tp2 = 0; | |
269 | for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { | |
270 | mg = &mi->groups[group]; | |
271 | if (!mg->supported) | |
272 | continue; | |
273 | ||
274 | mr = minstrel_get_ratestats(mi, mg->max_prob_rate); | |
275 | if (cur_prob_tp < mr->cur_tp && | |
276 | minstrel_mcs_groups[group].streams == 1) { | |
277 | mi->max_prob_rate = mg->max_prob_rate; | |
278 | cur_prob = mr->cur_prob; | |
009271f9 | 279 | cur_prob_tp = mr->cur_tp; |
ec8aa669 FF |
280 | } |
281 | ||
282 | mr = minstrel_get_ratestats(mi, mg->max_tp_rate); | |
283 | if (cur_tp < mr->cur_tp) { | |
284 | mi->max_tp_rate = mg->max_tp_rate; | |
285 | cur_tp = mr->cur_tp; | |
286 | } | |
287 | ||
288 | mr = minstrel_get_ratestats(mi, mg->max_tp_rate2); | |
289 | if (cur_tp2 < mr->cur_tp) { | |
290 | mi->max_tp_rate2 = mg->max_tp_rate2; | |
291 | cur_tp2 = mr->cur_tp; | |
292 | } | |
293 | } | |
294 | ||
295 | mi->stats_update = jiffies; | |
296 | } | |
297 | ||
298 | static bool | |
299 | minstrel_ht_txstat_valid(struct ieee80211_tx_rate *rate) | |
300 | { | |
301 | if (!rate->count) | |
302 | return false; | |
303 | ||
304 | if (rate->idx < 0) | |
305 | return false; | |
306 | ||
307 | return !!(rate->flags & IEEE80211_TX_RC_MCS); | |
308 | } | |
309 | ||
310 | static void | |
311 | minstrel_next_sample_idx(struct minstrel_ht_sta *mi) | |
312 | { | |
313 | struct minstrel_mcs_group_data *mg; | |
314 | ||
315 | for (;;) { | |
316 | mi->sample_group++; | |
317 | mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups); | |
318 | mg = &mi->groups[mi->sample_group]; | |
319 | ||
320 | if (!mg->supported) | |
321 | continue; | |
322 | ||
323 | if (++mg->index >= MCS_GROUP_RATES) { | |
324 | mg->index = 0; | |
325 | if (++mg->column >= ARRAY_SIZE(sample_table)) | |
326 | mg->column = 0; | |
327 | } | |
328 | break; | |
329 | } | |
330 | } | |
331 | ||
332 | static void | |
d5ece215 JL |
333 | minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx, |
334 | bool primary) | |
ec8aa669 FF |
335 | { |
336 | int group, orig_group; | |
337 | ||
338 | orig_group = group = *idx / MCS_GROUP_RATES; | |
339 | while (group > 0) { | |
340 | group--; | |
341 | ||
342 | if (!mi->groups[group].supported) | |
343 | continue; | |
344 | ||
345 | if (minstrel_mcs_groups[group].streams > | |
346 | minstrel_mcs_groups[orig_group].streams) | |
347 | continue; | |
348 | ||
349 | if (primary) | |
350 | *idx = mi->groups[group].max_tp_rate; | |
351 | else | |
352 | *idx = mi->groups[group].max_tp_rate2; | |
353 | break; | |
354 | } | |
355 | } | |
356 | ||
357 | static void | |
358 | minstrel_aggr_check(struct minstrel_priv *mp, struct ieee80211_sta *pubsta, struct sk_buff *skb) | |
359 | { | |
360 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; | |
361 | struct sta_info *sta = container_of(pubsta, struct sta_info, sta); | |
362 | u16 tid; | |
363 | ||
364 | if (unlikely(!ieee80211_is_data_qos(hdr->frame_control))) | |
365 | return; | |
366 | ||
367 | if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE))) | |
368 | return; | |
369 | ||
370 | tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; | |
a622ab72 | 371 | if (likely(sta->ampdu_mlme.tid_tx[tid])) |
ec8aa669 FF |
372 | return; |
373 | ||
48124d1a LR |
374 | if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO) |
375 | return; | |
376 | ||
ec8aa669 FF |
377 | ieee80211_start_tx_ba_session(pubsta, tid); |
378 | } | |
379 | ||
380 | static void | |
381 | minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, | |
382 | struct ieee80211_sta *sta, void *priv_sta, | |
383 | struct sk_buff *skb) | |
384 | { | |
385 | struct minstrel_ht_sta_priv *msp = priv_sta; | |
386 | struct minstrel_ht_sta *mi = &msp->ht; | |
387 | struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); | |
388 | struct ieee80211_tx_rate *ar = info->status.rates; | |
389 | struct minstrel_rate_stats *rate, *rate2; | |
390 | struct minstrel_priv *mp = priv; | |
391 | bool last = false; | |
392 | int group; | |
393 | int i = 0; | |
394 | ||
395 | if (!msp->is_ht) | |
396 | return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb); | |
397 | ||
398 | /* This packet was aggregated but doesn't carry status info */ | |
399 | if ((info->flags & IEEE80211_TX_CTL_AMPDU) && | |
400 | !(info->flags & IEEE80211_TX_STAT_AMPDU)) | |
401 | return; | |
402 | ||
15d46f38 BS |
403 | if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) { |
404 | info->status.ampdu_ack_len = | |
405 | (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0); | |
ec8aa669 FF |
406 | info->status.ampdu_len = 1; |
407 | } | |
408 | ||
409 | mi->ampdu_packets++; | |
410 | mi->ampdu_len += info->status.ampdu_len; | |
411 | ||
412 | if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) { | |
c7317e41 FF |
413 | mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len); |
414 | mi->sample_tries = 2; | |
ec8aa669 FF |
415 | mi->sample_count--; |
416 | } | |
417 | ||
418 | if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) { | |
419 | mi->sample_packets += info->status.ampdu_len; | |
420 | minstrel_next_sample_idx(mi); | |
421 | } | |
422 | ||
423 | for (i = 0; !last; i++) { | |
424 | last = (i == IEEE80211_TX_MAX_RATES - 1) || | |
425 | !minstrel_ht_txstat_valid(&ar[i + 1]); | |
426 | ||
427 | if (!minstrel_ht_txstat_valid(&ar[i])) | |
428 | break; | |
429 | ||
430 | group = minstrel_ht_get_group_idx(&ar[i]); | |
431 | rate = &mi->groups[group].rates[ar[i].idx % 8]; | |
432 | ||
15d46f38 | 433 | if (last) |
ec8aa669 FF |
434 | rate->success += info->status.ampdu_ack_len; |
435 | ||
436 | rate->attempts += ar[i].count * info->status.ampdu_len; | |
437 | } | |
438 | ||
439 | /* | |
440 | * check for sudden death of spatial multiplexing, | |
441 | * downgrade to a lower number of streams if necessary. | |
442 | */ | |
443 | rate = minstrel_get_ratestats(mi, mi->max_tp_rate); | |
444 | if (rate->attempts > 30 && | |
445 | MINSTREL_FRAC(rate->success, rate->attempts) < | |
446 | MINSTREL_FRAC(20, 100)) | |
447 | minstrel_downgrade_rate(mi, &mi->max_tp_rate, true); | |
448 | ||
449 | rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2); | |
ecc3d5ae ML |
450 | if (rate2->attempts > 30 && |
451 | MINSTREL_FRAC(rate2->success, rate2->attempts) < | |
ec8aa669 FF |
452 | MINSTREL_FRAC(20, 100)) |
453 | minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false); | |
454 | ||
455 | if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) { | |
456 | minstrel_ht_update_stats(mp, mi); | |
457 | minstrel_aggr_check(mp, sta, skb); | |
458 | } | |
459 | } | |
460 | ||
461 | static void | |
462 | minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, | |
463 | int index) | |
464 | { | |
465 | struct minstrel_rate_stats *mr; | |
466 | const struct mcs_group *group; | |
467 | unsigned int tx_time, tx_time_rtscts, tx_time_data; | |
468 | unsigned int cw = mp->cw_min; | |
469 | unsigned int t_slot = 9; /* FIXME */ | |
470 | unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len); | |
471 | ||
472 | mr = minstrel_get_ratestats(mi, index); | |
473 | if (mr->probability < MINSTREL_FRAC(1, 10)) { | |
474 | mr->retry_count = 1; | |
475 | mr->retry_count_rtscts = 1; | |
476 | return; | |
477 | } | |
478 | ||
479 | mr->retry_count = 2; | |
480 | mr->retry_count_rtscts = 2; | |
481 | mr->retry_updated = true; | |
482 | ||
483 | group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; | |
484 | tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len; | |
485 | tx_time = 2 * (t_slot + mi->overhead + tx_time_data); | |
486 | tx_time_rtscts = 2 * (t_slot + mi->overhead_rtscts + tx_time_data); | |
487 | do { | |
488 | cw = (cw << 1) | 1; | |
489 | cw = min(cw, mp->cw_max); | |
490 | tx_time += cw + t_slot + mi->overhead; | |
491 | tx_time_rtscts += cw + t_slot + mi->overhead_rtscts; | |
492 | if (tx_time_rtscts < mp->segment_size) | |
493 | mr->retry_count_rtscts++; | |
494 | } while ((tx_time < mp->segment_size) && | |
495 | (++mr->retry_count < mp->max_retry)); | |
496 | } | |
497 | ||
498 | ||
499 | static void | |
500 | minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, | |
501 | struct ieee80211_tx_rate *rate, int index, | |
502 | struct ieee80211_tx_rate_control *txrc, | |
503 | bool sample, bool rtscts) | |
504 | { | |
505 | const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; | |
506 | struct minstrel_rate_stats *mr; | |
507 | ||
508 | mr = minstrel_get_ratestats(mi, index); | |
509 | if (!mr->retry_updated) | |
510 | minstrel_calc_retransmit(mp, mi, index); | |
511 | ||
c7317e41 FF |
512 | if (sample) |
513 | rate->count = 1; | |
514 | else if (mr->probability < MINSTREL_FRAC(20, 100)) | |
ec8aa669 FF |
515 | rate->count = 2; |
516 | else if (rtscts) | |
517 | rate->count = mr->retry_count_rtscts; | |
518 | else | |
519 | rate->count = mr->retry_count; | |
520 | ||
521 | rate->flags = IEEE80211_TX_RC_MCS | group->flags; | |
522 | if (txrc->short_preamble) | |
523 | rate->flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE; | |
524 | if (txrc->rts || rtscts) | |
525 | rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS; | |
526 | rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES; | |
527 | } | |
528 | ||
529 | static inline int | |
530 | minstrel_get_duration(int index) | |
531 | { | |
532 | const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; | |
533 | return group->duration[index % MCS_GROUP_RATES]; | |
534 | } | |
535 | ||
536 | static int | |
537 | minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) | |
538 | { | |
539 | struct minstrel_rate_stats *mr; | |
540 | struct minstrel_mcs_group_data *mg; | |
541 | int sample_idx = 0; | |
542 | ||
543 | if (mi->sample_wait > 0) { | |
544 | mi->sample_wait--; | |
545 | return -1; | |
546 | } | |
547 | ||
548 | if (!mi->sample_tries) | |
549 | return -1; | |
550 | ||
551 | mi->sample_tries--; | |
552 | mg = &mi->groups[mi->sample_group]; | |
553 | sample_idx = sample_table[mg->column][mg->index]; | |
554 | mr = &mg->rates[sample_idx]; | |
555 | sample_idx += mi->sample_group * MCS_GROUP_RATES; | |
556 | ||
557 | /* | |
558 | * When not using MRR, do not sample if the probability is already | |
559 | * higher than 95% to avoid wasting airtime | |
560 | */ | |
561 | if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100))) | |
562 | goto next; | |
563 | ||
564 | /* | |
565 | * Make sure that lower rates get sampled only occasionally, | |
566 | * if the link is working perfectly. | |
567 | */ | |
568 | if (minstrel_get_duration(sample_idx) > | |
569 | minstrel_get_duration(mi->max_tp_rate)) { | |
c7317e41 | 570 | if (mr->sample_skipped < 20) |
ec8aa669 FF |
571 | goto next; |
572 | ||
573 | if (mi->sample_slow++ > 2) | |
574 | goto next; | |
575 | } | |
576 | ||
577 | return sample_idx; | |
578 | ||
579 | next: | |
580 | minstrel_next_sample_idx(mi); | |
581 | return -1; | |
582 | } | |
583 | ||
584 | static void | |
585 | minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, | |
586 | struct ieee80211_tx_rate_control *txrc) | |
587 | { | |
588 | struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); | |
589 | struct ieee80211_tx_rate *ar = info->status.rates; | |
590 | struct minstrel_ht_sta_priv *msp = priv_sta; | |
591 | struct minstrel_ht_sta *mi = &msp->ht; | |
592 | struct minstrel_priv *mp = priv; | |
593 | int sample_idx; | |
c7317e41 | 594 | bool sample = false; |
ec8aa669 FF |
595 | |
596 | if (rate_control_send_low(sta, priv_sta, txrc)) | |
597 | return; | |
598 | ||
599 | if (!msp->is_ht) | |
600 | return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc); | |
601 | ||
602 | info->flags |= mi->tx_flags; | |
603 | sample_idx = minstrel_get_sample_rate(mp, mi); | |
604 | if (sample_idx >= 0) { | |
c7317e41 | 605 | sample = true; |
ec8aa669 FF |
606 | minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx, |
607 | txrc, true, false); | |
608 | minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate, | |
c7317e41 | 609 | txrc, false, false); |
ec8aa669 FF |
610 | info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; |
611 | } else { | |
612 | minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate, | |
613 | txrc, false, false); | |
614 | minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2, | |
615 | txrc, false, true); | |
616 | } | |
c7317e41 | 617 | minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, txrc, false, !sample); |
ec8aa669 FF |
618 | |
619 | ar[3].count = 0; | |
620 | ar[3].idx = -1; | |
621 | ||
622 | mi->total_packets++; | |
623 | ||
624 | /* wraparound */ | |
625 | if (mi->total_packets == ~0) { | |
626 | mi->total_packets = 0; | |
627 | mi->sample_packets = 0; | |
628 | } | |
629 | } | |
630 | ||
631 | static void | |
632 | minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, | |
633 | struct ieee80211_sta *sta, void *priv_sta, | |
634 | enum nl80211_channel_type oper_chan_type) | |
635 | { | |
636 | struct minstrel_priv *mp = priv; | |
637 | struct minstrel_ht_sta_priv *msp = priv_sta; | |
638 | struct minstrel_ht_sta *mi = &msp->ht; | |
639 | struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs; | |
640 | struct ieee80211_local *local = hw_to_local(mp->hw); | |
641 | u16 sta_cap = sta->ht_cap.cap; | |
642 | int ack_dur; | |
643 | int stbc; | |
644 | int i; | |
645 | ||
646 | /* fall back to the old minstrel for legacy stations */ | |
00fc90c8 | 647 | if (!sta->ht_cap.ht_supported) { |
ec8aa669 FF |
648 | msp->is_ht = false; |
649 | memset(&msp->legacy, 0, sizeof(msp->legacy)); | |
650 | msp->legacy.r = msp->ratelist; | |
651 | msp->legacy.sample_table = msp->sample_table; | |
652 | return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy); | |
653 | } | |
654 | ||
655 | BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != | |
656 | MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS); | |
657 | ||
658 | msp->is_ht = true; | |
659 | memset(mi, 0, sizeof(*mi)); | |
660 | mi->stats_update = jiffies; | |
661 | ||
662 | ack_dur = ieee80211_frame_duration(local, 10, 60, 1, 1); | |
663 | mi->overhead = ieee80211_frame_duration(local, 0, 60, 1, 1) + ack_dur; | |
664 | mi->overhead_rtscts = mi->overhead + 2 * ack_dur; | |
665 | ||
666 | mi->avg_ampdu_len = MINSTREL_FRAC(1, 1); | |
667 | ||
668 | /* When using MRR, sample more on the first attempt, without delay */ | |
669 | if (mp->has_mrr) { | |
670 | mi->sample_count = 16; | |
671 | mi->sample_wait = 0; | |
672 | } else { | |
673 | mi->sample_count = 8; | |
674 | mi->sample_wait = 8; | |
675 | } | |
676 | mi->sample_tries = 4; | |
677 | ||
678 | stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >> | |
679 | IEEE80211_HT_CAP_RX_STBC_SHIFT; | |
680 | mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT; | |
681 | ||
682 | if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING) | |
683 | mi->tx_flags |= IEEE80211_TX_CTL_LDPC; | |
684 | ||
685 | if (oper_chan_type != NL80211_CHAN_HT40MINUS && | |
686 | oper_chan_type != NL80211_CHAN_HT40PLUS) | |
687 | sta_cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40; | |
688 | ||
689 | for (i = 0; i < ARRAY_SIZE(mi->groups); i++) { | |
690 | u16 req = 0; | |
691 | ||
692 | mi->groups[i].supported = 0; | |
693 | if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) { | |
694 | if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) | |
695 | req |= IEEE80211_HT_CAP_SGI_40; | |
696 | else | |
697 | req |= IEEE80211_HT_CAP_SGI_20; | |
698 | } | |
699 | ||
700 | if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) | |
701 | req |= IEEE80211_HT_CAP_SUP_WIDTH_20_40; | |
702 | ||
703 | if ((sta_cap & req) != req) | |
704 | continue; | |
705 | ||
706 | mi->groups[i].supported = | |
707 | mcs->rx_mask[minstrel_mcs_groups[i].streams - 1]; | |
708 | } | |
709 | } | |
710 | ||
711 | static void | |
712 | minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband, | |
713 | struct ieee80211_sta *sta, void *priv_sta) | |
714 | { | |
715 | struct minstrel_priv *mp = priv; | |
716 | ||
717 | minstrel_ht_update_caps(priv, sband, sta, priv_sta, mp->hw->conf.channel_type); | |
718 | } | |
719 | ||
720 | static void | |
721 | minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband, | |
722 | struct ieee80211_sta *sta, void *priv_sta, | |
723 | u32 changed, enum nl80211_channel_type oper_chan_type) | |
724 | { | |
725 | minstrel_ht_update_caps(priv, sband, sta, priv_sta, oper_chan_type); | |
726 | } | |
727 | ||
728 | static void * | |
729 | minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp) | |
730 | { | |
731 | struct ieee80211_supported_band *sband; | |
732 | struct minstrel_ht_sta_priv *msp; | |
733 | struct minstrel_priv *mp = priv; | |
734 | struct ieee80211_hw *hw = mp->hw; | |
735 | int max_rates = 0; | |
736 | int i; | |
737 | ||
738 | for (i = 0; i < IEEE80211_NUM_BANDS; i++) { | |
739 | sband = hw->wiphy->bands[i]; | |
740 | if (sband && sband->n_bitrates > max_rates) | |
741 | max_rates = sband->n_bitrates; | |
742 | } | |
743 | ||
744 | msp = kzalloc(sizeof(struct minstrel_ht_sta), gfp); | |
745 | if (!msp) | |
746 | return NULL; | |
747 | ||
748 | msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp); | |
749 | if (!msp->ratelist) | |
750 | goto error; | |
751 | ||
752 | msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp); | |
753 | if (!msp->sample_table) | |
754 | goto error1; | |
755 | ||
756 | return msp; | |
757 | ||
758 | error1: | |
7e988014 | 759 | kfree(msp->ratelist); |
ec8aa669 FF |
760 | error: |
761 | kfree(msp); | |
762 | return NULL; | |
763 | } | |
764 | ||
765 | static void | |
766 | minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta) | |
767 | { | |
768 | struct minstrel_ht_sta_priv *msp = priv_sta; | |
769 | ||
770 | kfree(msp->sample_table); | |
771 | kfree(msp->ratelist); | |
772 | kfree(msp); | |
773 | } | |
774 | ||
775 | static void * | |
776 | minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) | |
777 | { | |
778 | return mac80211_minstrel.alloc(hw, debugfsdir); | |
779 | } | |
780 | ||
781 | static void | |
782 | minstrel_ht_free(void *priv) | |
783 | { | |
784 | mac80211_minstrel.free(priv); | |
785 | } | |
786 | ||
787 | static struct rate_control_ops mac80211_minstrel_ht = { | |
788 | .name = "minstrel_ht", | |
789 | .tx_status = minstrel_ht_tx_status, | |
790 | .get_rate = minstrel_ht_get_rate, | |
791 | .rate_init = minstrel_ht_rate_init, | |
792 | .rate_update = minstrel_ht_rate_update, | |
793 | .alloc_sta = minstrel_ht_alloc_sta, | |
794 | .free_sta = minstrel_ht_free_sta, | |
795 | .alloc = minstrel_ht_alloc, | |
796 | .free = minstrel_ht_free, | |
797 | #ifdef CONFIG_MAC80211_DEBUGFS | |
798 | .add_sta_debugfs = minstrel_ht_add_sta_debugfs, | |
799 | .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs, | |
800 | #endif | |
801 | }; | |
802 | ||
803 | ||
804 | static void | |
805 | init_sample_table(void) | |
806 | { | |
807 | int col, i, new_idx; | |
808 | u8 rnd[MCS_GROUP_RATES]; | |
809 | ||
810 | memset(sample_table, 0xff, sizeof(sample_table)); | |
811 | for (col = 0; col < SAMPLE_COLUMNS; col++) { | |
812 | for (i = 0; i < MCS_GROUP_RATES; i++) { | |
813 | get_random_bytes(rnd, sizeof(rnd)); | |
814 | new_idx = (i + rnd[i]) % MCS_GROUP_RATES; | |
815 | ||
816 | while (sample_table[col][new_idx] != 0xff) | |
817 | new_idx = (new_idx + 1) % MCS_GROUP_RATES; | |
818 | ||
819 | sample_table[col][new_idx] = i; | |
820 | } | |
821 | } | |
822 | } | |
823 | ||
824 | int __init | |
825 | rc80211_minstrel_ht_init(void) | |
826 | { | |
827 | init_sample_table(); | |
828 | return ieee80211_rate_control_register(&mac80211_minstrel_ht); | |
829 | } | |
830 | ||
831 | void | |
832 | rc80211_minstrel_ht_exit(void) | |
833 | { | |
834 | ieee80211_rate_control_unregister(&mac80211_minstrel_ht); | |
835 | } |