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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 | ||
a5f69d94 HS |
39 | /* |
40 | * Define group sort order: HT40 -> SGI -> #streams | |
41 | */ | |
42 | #define GROUP_IDX(_streams, _sgi, _ht40) \ | |
43 | MINSTREL_MAX_STREAMS * 2 * _ht40 + \ | |
44 | MINSTREL_MAX_STREAMS * _sgi + \ | |
45 | _streams - 1 | |
46 | ||
ec8aa669 | 47 | /* MCS rate information for an MCS group */ |
a5f69d94 HS |
48 | #define MCS_GROUP(_streams, _sgi, _ht40) \ |
49 | [GROUP_IDX(_streams, _sgi, _ht40)] = { \ | |
ec8aa669 FF |
50 | .streams = _streams, \ |
51 | .flags = \ | |
52 | (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \ | |
53 | (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \ | |
54 | .duration = { \ | |
55 | MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \ | |
56 | MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \ | |
57 | MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \ | |
58 | MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \ | |
59 | MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \ | |
60 | MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \ | |
61 | MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \ | |
62 | MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \ | |
63 | } \ | |
64 | } | |
65 | ||
66 | /* | |
67 | * To enable sufficiently targeted rate sampling, MCS rates are divided into | |
68 | * groups, based on the number of streams and flags (HT40, SGI) that they | |
69 | * use. | |
a5f69d94 HS |
70 | * |
71 | * Sortorder has to be fixed for GROUP_IDX macro to be applicable: | |
72 | * HT40 -> SGI -> #streams | |
ec8aa669 FF |
73 | */ |
74 | const struct mcs_group minstrel_mcs_groups[] = { | |
75 | MCS_GROUP(1, 0, 0), | |
76 | MCS_GROUP(2, 0, 0), | |
77 | #if MINSTREL_MAX_STREAMS >= 3 | |
78 | MCS_GROUP(3, 0, 0), | |
79 | #endif | |
80 | ||
81 | MCS_GROUP(1, 1, 0), | |
82 | MCS_GROUP(2, 1, 0), | |
83 | #if MINSTREL_MAX_STREAMS >= 3 | |
84 | MCS_GROUP(3, 1, 0), | |
85 | #endif | |
86 | ||
87 | MCS_GROUP(1, 0, 1), | |
88 | MCS_GROUP(2, 0, 1), | |
89 | #if MINSTREL_MAX_STREAMS >= 3 | |
90 | MCS_GROUP(3, 0, 1), | |
91 | #endif | |
92 | ||
93 | MCS_GROUP(1, 1, 1), | |
94 | MCS_GROUP(2, 1, 1), | |
95 | #if MINSTREL_MAX_STREAMS >= 3 | |
96 | MCS_GROUP(3, 1, 1), | |
97 | #endif | |
98 | }; | |
99 | ||
100 | static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES]; | |
101 | ||
102 | /* | |
103 | * Perform EWMA (Exponentially Weighted Moving Average) calculation | |
104 | */ | |
105 | static int | |
106 | minstrel_ewma(int old, int new, int weight) | |
107 | { | |
108 | return (new * (100 - weight) + old * weight) / 100; | |
109 | } | |
110 | ||
111 | /* | |
112 | * Look up an MCS group index based on mac80211 rate information | |
113 | */ | |
114 | static int | |
115 | minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate) | |
116 | { | |
a5f69d94 HS |
117 | return GROUP_IDX((rate->idx / MCS_GROUP_RATES) + 1, |
118 | !!(rate->flags & IEEE80211_TX_RC_SHORT_GI), | |
119 | !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH)); | |
ec8aa669 FF |
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 | |
6048d763 | 133 | minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr) |
ec8aa669 FF |
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 | |
6048d763 | 159 | minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate) |
ec8aa669 FF |
160 | { |
161 | struct minstrel_rate_stats *mr; | |
162 | unsigned int usecs; | |
163 | ||
164 | mr = &mi->groups[group].rates[rate]; | |
165 | ||
166 | if (mr->probability < MINSTREL_FRAC(1, 10)) { | |
167 | mr->cur_tp = 0; | |
168 | return; | |
169 | } | |
170 | ||
171 | usecs = mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len); | |
172 | usecs += minstrel_mcs_groups[group].duration[rate]; | |
173 | mr->cur_tp = MINSTREL_TRUNC((1000000 / usecs) * mr->probability); | |
174 | } | |
175 | ||
176 | /* | |
177 | * Update rate statistics and select new primary rates | |
178 | * | |
179 | * Rules for rate selection: | |
180 | * - max_prob_rate must use only one stream, as a tradeoff between delivery | |
181 | * probability and throughput during strong fluctuations | |
182 | * - as long as the max prob rate has a probability of more than 3/4, pick | |
183 | * higher throughput rates, even if the probablity is a bit lower | |
184 | */ | |
185 | static void | |
186 | minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) | |
187 | { | |
188 | struct minstrel_mcs_group_data *mg; | |
189 | struct minstrel_rate_stats *mr; | |
190 | int cur_prob, cur_prob_tp, cur_tp, cur_tp2; | |
191 | int group, i, index; | |
192 | ||
193 | if (mi->ampdu_packets > 0) { | |
194 | mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len, | |
195 | MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL); | |
196 | mi->ampdu_len = 0; | |
197 | mi->ampdu_packets = 0; | |
198 | } | |
199 | ||
200 | mi->sample_slow = 0; | |
201 | mi->sample_count = 0; | |
202 | mi->max_tp_rate = 0; | |
203 | mi->max_tp_rate2 = 0; | |
204 | mi->max_prob_rate = 0; | |
205 | ||
206 | for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { | |
207 | cur_prob = 0; | |
208 | cur_prob_tp = 0; | |
209 | cur_tp = 0; | |
210 | cur_tp2 = 0; | |
211 | ||
212 | mg = &mi->groups[group]; | |
213 | if (!mg->supported) | |
214 | continue; | |
215 | ||
216 | mg->max_tp_rate = 0; | |
217 | mg->max_tp_rate2 = 0; | |
218 | mg->max_prob_rate = 0; | |
219 | mi->sample_count++; | |
220 | ||
221 | for (i = 0; i < MCS_GROUP_RATES; i++) { | |
222 | if (!(mg->supported & BIT(i))) | |
223 | continue; | |
224 | ||
225 | mr = &mg->rates[i]; | |
226 | mr->retry_updated = false; | |
227 | index = MCS_GROUP_RATES * group + i; | |
6048d763 PK |
228 | minstrel_calc_rate_ewma(mr); |
229 | minstrel_ht_calc_tp(mi, group, i); | |
ec8aa669 FF |
230 | |
231 | if (!mr->cur_tp) | |
232 | continue; | |
233 | ||
234 | /* ignore the lowest rate of each single-stream group */ | |
235 | if (!i && minstrel_mcs_groups[group].streams == 1) | |
236 | continue; | |
237 | ||
238 | if ((mr->cur_tp > cur_prob_tp && mr->probability > | |
239 | MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) { | |
240 | mg->max_prob_rate = index; | |
241 | cur_prob = mr->probability; | |
009271f9 | 242 | cur_prob_tp = mr->cur_tp; |
ec8aa669 FF |
243 | } |
244 | ||
245 | if (mr->cur_tp > cur_tp) { | |
246 | swap(index, mg->max_tp_rate); | |
247 | cur_tp = mr->cur_tp; | |
248 | mr = minstrel_get_ratestats(mi, index); | |
249 | } | |
250 | ||
251 | if (index >= mg->max_tp_rate) | |
252 | continue; | |
253 | ||
254 | if (mr->cur_tp > cur_tp2) { | |
255 | mg->max_tp_rate2 = index; | |
256 | cur_tp2 = mr->cur_tp; | |
257 | } | |
258 | } | |
259 | } | |
260 | ||
25985edc | 261 | /* try to sample up to half of the available rates during each interval */ |
ec8aa669 FF |
262 | mi->sample_count *= 4; |
263 | ||
264 | cur_prob = 0; | |
265 | cur_prob_tp = 0; | |
266 | cur_tp = 0; | |
267 | cur_tp2 = 0; | |
268 | for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { | |
269 | mg = &mi->groups[group]; | |
270 | if (!mg->supported) | |
271 | continue; | |
272 | ||
273 | mr = minstrel_get_ratestats(mi, mg->max_prob_rate); | |
274 | if (cur_prob_tp < mr->cur_tp && | |
275 | minstrel_mcs_groups[group].streams == 1) { | |
276 | mi->max_prob_rate = mg->max_prob_rate; | |
277 | cur_prob = mr->cur_prob; | |
009271f9 | 278 | cur_prob_tp = mr->cur_tp; |
ec8aa669 FF |
279 | } |
280 | ||
281 | mr = minstrel_get_ratestats(mi, mg->max_tp_rate); | |
282 | if (cur_tp < mr->cur_tp) { | |
89888e36 LB |
283 | mi->max_tp_rate2 = mi->max_tp_rate; |
284 | cur_tp2 = cur_tp; | |
ec8aa669 FF |
285 | mi->max_tp_rate = mg->max_tp_rate; |
286 | cur_tp = mr->cur_tp; | |
287 | } | |
288 | ||
289 | mr = minstrel_get_ratestats(mi, mg->max_tp_rate2); | |
290 | if (cur_tp2 < mr->cur_tp) { | |
291 | mi->max_tp_rate2 = mg->max_tp_rate2; | |
292 | cur_tp2 = mr->cur_tp; | |
293 | } | |
294 | } | |
295 | ||
296 | mi->stats_update = jiffies; | |
297 | } | |
298 | ||
299 | static bool | |
300 | minstrel_ht_txstat_valid(struct ieee80211_tx_rate *rate) | |
301 | { | |
b79296be | 302 | if (rate->idx < 0) |
ec8aa669 FF |
303 | return false; |
304 | ||
b79296be | 305 | if (!rate->count) |
ec8aa669 FF |
306 | return false; |
307 | ||
308 | return !!(rate->flags & IEEE80211_TX_RC_MCS); | |
309 | } | |
310 | ||
311 | static void | |
312 | minstrel_next_sample_idx(struct minstrel_ht_sta *mi) | |
313 | { | |
314 | struct minstrel_mcs_group_data *mg; | |
315 | ||
316 | for (;;) { | |
317 | mi->sample_group++; | |
318 | mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups); | |
319 | mg = &mi->groups[mi->sample_group]; | |
320 | ||
321 | if (!mg->supported) | |
322 | continue; | |
323 | ||
324 | if (++mg->index >= MCS_GROUP_RATES) { | |
325 | mg->index = 0; | |
326 | if (++mg->column >= ARRAY_SIZE(sample_table)) | |
327 | mg->column = 0; | |
328 | } | |
329 | break; | |
330 | } | |
331 | } | |
332 | ||
333 | static void | |
d5ece215 JL |
334 | minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx, |
335 | bool primary) | |
ec8aa669 FF |
336 | { |
337 | int group, orig_group; | |
338 | ||
339 | orig_group = group = *idx / MCS_GROUP_RATES; | |
340 | while (group > 0) { | |
341 | group--; | |
342 | ||
343 | if (!mi->groups[group].supported) | |
344 | continue; | |
345 | ||
346 | if (minstrel_mcs_groups[group].streams > | |
347 | minstrel_mcs_groups[orig_group].streams) | |
348 | continue; | |
349 | ||
350 | if (primary) | |
351 | *idx = mi->groups[group].max_tp_rate; | |
352 | else | |
353 | *idx = mi->groups[group].max_tp_rate2; | |
354 | break; | |
355 | } | |
356 | } | |
357 | ||
358 | static void | |
6048d763 | 359 | minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb) |
ec8aa669 FF |
360 | { |
361 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; | |
362 | struct sta_info *sta = container_of(pubsta, struct sta_info, sta); | |
363 | u16 tid; | |
364 | ||
365 | if (unlikely(!ieee80211_is_data_qos(hdr->frame_control))) | |
366 | return; | |
367 | ||
368 | if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE))) | |
369 | return; | |
370 | ||
371 | tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; | |
a622ab72 | 372 | if (likely(sta->ampdu_mlme.tid_tx[tid])) |
ec8aa669 FF |
373 | return; |
374 | ||
48124d1a LR |
375 | if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO) |
376 | return; | |
377 | ||
bd2ce6e4 | 378 | ieee80211_start_tx_ba_session(pubsta, tid, 5000); |
ec8aa669 FF |
379 | } |
380 | ||
381 | static void | |
382 | minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, | |
383 | struct ieee80211_sta *sta, void *priv_sta, | |
384 | struct sk_buff *skb) | |
385 | { | |
386 | struct minstrel_ht_sta_priv *msp = priv_sta; | |
387 | struct minstrel_ht_sta *mi = &msp->ht; | |
388 | struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); | |
389 | struct ieee80211_tx_rate *ar = info->status.rates; | |
390 | struct minstrel_rate_stats *rate, *rate2; | |
391 | struct minstrel_priv *mp = priv; | |
392 | bool last = false; | |
393 | int group; | |
394 | int i = 0; | |
395 | ||
396 | if (!msp->is_ht) | |
397 | return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb); | |
398 | ||
399 | /* This packet was aggregated but doesn't carry status info */ | |
400 | if ((info->flags & IEEE80211_TX_CTL_AMPDU) && | |
401 | !(info->flags & IEEE80211_TX_STAT_AMPDU)) | |
402 | return; | |
403 | ||
15d46f38 BS |
404 | if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) { |
405 | info->status.ampdu_ack_len = | |
406 | (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0); | |
ec8aa669 FF |
407 | info->status.ampdu_len = 1; |
408 | } | |
409 | ||
410 | mi->ampdu_packets++; | |
411 | mi->ampdu_len += info->status.ampdu_len; | |
412 | ||
413 | if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) { | |
c7317e41 FF |
414 | mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len); |
415 | mi->sample_tries = 2; | |
ec8aa669 FF |
416 | mi->sample_count--; |
417 | } | |
418 | ||
8d5eab5a | 419 | if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) |
ec8aa669 | 420 | mi->sample_packets += info->status.ampdu_len; |
ec8aa669 FF |
421 | |
422 | for (i = 0; !last; i++) { | |
423 | last = (i == IEEE80211_TX_MAX_RATES - 1) || | |
424 | !minstrel_ht_txstat_valid(&ar[i + 1]); | |
425 | ||
426 | if (!minstrel_ht_txstat_valid(&ar[i])) | |
427 | break; | |
428 | ||
429 | group = minstrel_ht_get_group_idx(&ar[i]); | |
430 | rate = &mi->groups[group].rates[ar[i].idx % 8]; | |
431 | ||
15d46f38 | 432 | if (last) |
ec8aa669 FF |
433 | rate->success += info->status.ampdu_ack_len; |
434 | ||
435 | rate->attempts += ar[i].count * info->status.ampdu_len; | |
436 | } | |
437 | ||
438 | /* | |
439 | * check for sudden death of spatial multiplexing, | |
440 | * downgrade to a lower number of streams if necessary. | |
441 | */ | |
442 | rate = minstrel_get_ratestats(mi, mi->max_tp_rate); | |
443 | if (rate->attempts > 30 && | |
444 | MINSTREL_FRAC(rate->success, rate->attempts) < | |
445 | MINSTREL_FRAC(20, 100)) | |
446 | minstrel_downgrade_rate(mi, &mi->max_tp_rate, true); | |
447 | ||
448 | rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2); | |
ecc3d5ae ML |
449 | if (rate2->attempts > 30 && |
450 | MINSTREL_FRAC(rate2->success, rate2->attempts) < | |
ec8aa669 FF |
451 | MINSTREL_FRAC(20, 100)) |
452 | minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false); | |
453 | ||
454 | if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) { | |
455 | minstrel_ht_update_stats(mp, mi); | |
64ed5cf0 | 456 | if (!(info->flags & IEEE80211_TX_CTL_AMPDU)) |
6048d763 | 457 | minstrel_aggr_check(sta, skb); |
ec8aa669 FF |
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; | |
8fddddff | 469 | unsigned int ctime = 0; |
ec8aa669 FF |
470 | unsigned int t_slot = 9; /* FIXME */ |
471 | unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len); | |
472 | ||
473 | mr = minstrel_get_ratestats(mi, index); | |
474 | if (mr->probability < MINSTREL_FRAC(1, 10)) { | |
475 | mr->retry_count = 1; | |
476 | mr->retry_count_rtscts = 1; | |
477 | return; | |
478 | } | |
479 | ||
480 | mr->retry_count = 2; | |
481 | mr->retry_count_rtscts = 2; | |
482 | mr->retry_updated = true; | |
483 | ||
484 | group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; | |
485 | tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len; | |
8fddddff DH |
486 | |
487 | /* Contention time for first 2 tries */ | |
488 | ctime = (t_slot * cw) >> 1; | |
489 | cw = min((cw << 1) | 1, mp->cw_max); | |
490 | ctime += (t_slot * cw) >> 1; | |
491 | cw = min((cw << 1) | 1, mp->cw_max); | |
492 | ||
493 | /* Total TX time for data and Contention after first 2 tries */ | |
494 | tx_time = ctime + 2 * (mi->overhead + tx_time_data); | |
495 | tx_time_rtscts = ctime + 2 * (mi->overhead_rtscts + tx_time_data); | |
496 | ||
497 | /* See how many more tries we can fit inside segment size */ | |
ec8aa669 | 498 | do { |
8fddddff DH |
499 | /* Contention time for this try */ |
500 | ctime = (t_slot * cw) >> 1; | |
501 | cw = min((cw << 1) | 1, mp->cw_max); | |
502 | ||
503 | /* Total TX time after this try */ | |
504 | tx_time += ctime + mi->overhead + tx_time_data; | |
505 | tx_time_rtscts += ctime + mi->overhead_rtscts + tx_time_data; | |
506 | ||
ec8aa669 FF |
507 | if (tx_time_rtscts < mp->segment_size) |
508 | mr->retry_count_rtscts++; | |
509 | } while ((tx_time < mp->segment_size) && | |
510 | (++mr->retry_count < mp->max_retry)); | |
511 | } | |
512 | ||
513 | ||
514 | static void | |
515 | minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, | |
516 | struct ieee80211_tx_rate *rate, int index, | |
ec8aa669 FF |
517 | bool sample, bool rtscts) |
518 | { | |
519 | const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; | |
520 | struct minstrel_rate_stats *mr; | |
521 | ||
522 | mr = minstrel_get_ratestats(mi, index); | |
523 | if (!mr->retry_updated) | |
524 | minstrel_calc_retransmit(mp, mi, index); | |
525 | ||
c7317e41 FF |
526 | if (sample) |
527 | rate->count = 1; | |
528 | else if (mr->probability < MINSTREL_FRAC(20, 100)) | |
ec8aa669 FF |
529 | rate->count = 2; |
530 | else if (rtscts) | |
531 | rate->count = mr->retry_count_rtscts; | |
532 | else | |
533 | rate->count = mr->retry_count; | |
534 | ||
535 | rate->flags = IEEE80211_TX_RC_MCS | group->flags; | |
9d468d22 | 536 | if (rtscts) |
ec8aa669 FF |
537 | rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS; |
538 | rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES; | |
539 | } | |
540 | ||
541 | static inline int | |
542 | minstrel_get_duration(int index) | |
543 | { | |
544 | const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; | |
545 | return group->duration[index % MCS_GROUP_RATES]; | |
546 | } | |
547 | ||
548 | static int | |
549 | minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) | |
550 | { | |
551 | struct minstrel_rate_stats *mr; | |
552 | struct minstrel_mcs_group_data *mg; | |
553 | int sample_idx = 0; | |
554 | ||
555 | if (mi->sample_wait > 0) { | |
556 | mi->sample_wait--; | |
557 | return -1; | |
558 | } | |
559 | ||
560 | if (!mi->sample_tries) | |
561 | return -1; | |
562 | ||
563 | mi->sample_tries--; | |
564 | mg = &mi->groups[mi->sample_group]; | |
565 | sample_idx = sample_table[mg->column][mg->index]; | |
566 | mr = &mg->rates[sample_idx]; | |
567 | sample_idx += mi->sample_group * MCS_GROUP_RATES; | |
8d5eab5a | 568 | minstrel_next_sample_idx(mi); |
ec8aa669 | 569 | |
ba6fa29c HS |
570 | /* |
571 | * Sampling might add some overhead (RTS, no aggregation) | |
572 | * to the frame. Hence, don't use sampling for the currently | |
573 | * used max TP rate. | |
574 | */ | |
575 | if (sample_idx == mi->max_tp_rate) | |
576 | return -1; | |
ec8aa669 FF |
577 | /* |
578 | * When not using MRR, do not sample if the probability is already | |
579 | * higher than 95% to avoid wasting airtime | |
580 | */ | |
581 | if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100))) | |
8d5eab5a | 582 | return -1; |
ec8aa669 FF |
583 | |
584 | /* | |
585 | * Make sure that lower rates get sampled only occasionally, | |
586 | * if the link is working perfectly. | |
587 | */ | |
588 | if (minstrel_get_duration(sample_idx) > | |
589 | minstrel_get_duration(mi->max_tp_rate)) { | |
c7317e41 | 590 | if (mr->sample_skipped < 20) |
8d5eab5a | 591 | return -1; |
ec8aa669 FF |
592 | |
593 | if (mi->sample_slow++ > 2) | |
8d5eab5a | 594 | return -1; |
ec8aa669 FF |
595 | } |
596 | ||
597 | return sample_idx; | |
ec8aa669 FF |
598 | } |
599 | ||
600 | static void | |
601 | minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, | |
602 | struct ieee80211_tx_rate_control *txrc) | |
603 | { | |
604 | struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); | |
605 | struct ieee80211_tx_rate *ar = info->status.rates; | |
606 | struct minstrel_ht_sta_priv *msp = priv_sta; | |
607 | struct minstrel_ht_sta *mi = &msp->ht; | |
608 | struct minstrel_priv *mp = priv; | |
609 | int sample_idx; | |
c7317e41 | 610 | bool sample = false; |
ec8aa669 FF |
611 | |
612 | if (rate_control_send_low(sta, priv_sta, txrc)) | |
613 | return; | |
614 | ||
615 | if (!msp->is_ht) | |
616 | return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc); | |
617 | ||
618 | info->flags |= mi->tx_flags; | |
6de062ce HS |
619 | |
620 | /* Don't use EAPOL frames for sampling on non-mrr hw */ | |
621 | if (mp->hw->max_rates == 1 && | |
622 | txrc->skb->protocol == cpu_to_be16(ETH_P_PAE)) | |
623 | sample_idx = -1; | |
624 | else | |
625 | sample_idx = minstrel_get_sample_rate(mp, mi); | |
24f7580e ZK |
626 | |
627 | #ifdef CONFIG_MAC80211_DEBUGFS | |
628 | /* use fixed index if set */ | |
2a9e6c58 SRR |
629 | if (mp->fixed_rate_idx != -1) { |
630 | mi->max_tp_rate = mp->fixed_rate_idx; | |
631 | mi->max_tp_rate2 = mp->fixed_rate_idx; | |
632 | mi->max_prob_rate = mp->fixed_rate_idx; | |
633 | sample_idx = -1; | |
634 | } | |
24f7580e ZK |
635 | #endif |
636 | ||
ec8aa669 | 637 | if (sample_idx >= 0) { |
c7317e41 | 638 | sample = true; |
ec8aa669 | 639 | minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx, |
6048d763 | 640 | true, false); |
ec8aa669 FF |
641 | info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; |
642 | } else { | |
643 | minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate, | |
6048d763 | 644 | false, false); |
ec8aa669 | 645 | } |
ec8aa669 | 646 | |
cf28d793 HS |
647 | if (mp->hw->max_rates >= 3) { |
648 | /* | |
649 | * At least 3 tx rates supported, use | |
650 | * sample_rate -> max_tp_rate -> max_prob_rate for sampling and | |
651 | * max_tp_rate -> max_tp_rate2 -> max_prob_rate by default. | |
652 | */ | |
653 | if (sample_idx >= 0) | |
654 | minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate, | |
6048d763 | 655 | false, false); |
cf28d793 HS |
656 | else |
657 | minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2, | |
6048d763 | 658 | false, true); |
cf28d793 HS |
659 | |
660 | minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, | |
6048d763 | 661 | false, !sample); |
cf28d793 HS |
662 | |
663 | ar[3].count = 0; | |
664 | ar[3].idx = -1; | |
665 | } else if (mp->hw->max_rates == 2) { | |
666 | /* | |
667 | * Only 2 tx rates supported, use | |
668 | * sample_rate -> max_prob_rate for sampling and | |
669 | * max_tp_rate -> max_prob_rate by default. | |
670 | */ | |
671 | minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_prob_rate, | |
6048d763 | 672 | false, !sample); |
cf28d793 HS |
673 | |
674 | ar[2].count = 0; | |
675 | ar[2].idx = -1; | |
676 | } else { | |
677 | /* Not using MRR, only use the first rate */ | |
678 | ar[1].count = 0; | |
679 | ar[1].idx = -1; | |
680 | } | |
ec8aa669 FF |
681 | |
682 | mi->total_packets++; | |
683 | ||
684 | /* wraparound */ | |
685 | if (mi->total_packets == ~0) { | |
686 | mi->total_packets = 0; | |
687 | mi->sample_packets = 0; | |
688 | } | |
689 | } | |
690 | ||
691 | static void | |
692 | minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, | |
64f68e5d | 693 | struct ieee80211_sta *sta, void *priv_sta) |
ec8aa669 FF |
694 | { |
695 | struct minstrel_priv *mp = priv; | |
696 | struct minstrel_ht_sta_priv *msp = priv_sta; | |
697 | struct minstrel_ht_sta *mi = &msp->ht; | |
698 | struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs; | |
ec8aa669 | 699 | u16 sta_cap = sta->ht_cap.cap; |
4dc217df | 700 | int n_supported = 0; |
ec8aa669 FF |
701 | int ack_dur; |
702 | int stbc; | |
703 | int i; | |
e9219779 | 704 | unsigned int smps; |
ec8aa669 FF |
705 | |
706 | /* fall back to the old minstrel for legacy stations */ | |
4dc217df FF |
707 | if (!sta->ht_cap.ht_supported) |
708 | goto use_legacy; | |
ec8aa669 FF |
709 | |
710 | BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != | |
711 | MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS); | |
712 | ||
713 | msp->is_ht = true; | |
714 | memset(mi, 0, sizeof(*mi)); | |
715 | mi->stats_update = jiffies; | |
716 | ||
4ee73f33 MK |
717 | ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1); |
718 | mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1) + ack_dur; | |
ec8aa669 FF |
719 | mi->overhead_rtscts = mi->overhead + 2 * ack_dur; |
720 | ||
721 | mi->avg_ampdu_len = MINSTREL_FRAC(1, 1); | |
722 | ||
723 | /* When using MRR, sample more on the first attempt, without delay */ | |
724 | if (mp->has_mrr) { | |
725 | mi->sample_count = 16; | |
726 | mi->sample_wait = 0; | |
727 | } else { | |
728 | mi->sample_count = 8; | |
729 | mi->sample_wait = 8; | |
730 | } | |
731 | mi->sample_tries = 4; | |
732 | ||
733 | stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >> | |
734 | IEEE80211_HT_CAP_RX_STBC_SHIFT; | |
735 | mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT; | |
736 | ||
737 | if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING) | |
738 | mi->tx_flags |= IEEE80211_TX_CTL_LDPC; | |
739 | ||
e9219779 HS |
740 | smps = (sta_cap & IEEE80211_HT_CAP_SM_PS) >> |
741 | IEEE80211_HT_CAP_SM_PS_SHIFT; | |
742 | ||
ec8aa669 FF |
743 | for (i = 0; i < ARRAY_SIZE(mi->groups); i++) { |
744 | u16 req = 0; | |
745 | ||
746 | mi->groups[i].supported = 0; | |
747 | if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) { | |
748 | if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) | |
749 | req |= IEEE80211_HT_CAP_SGI_40; | |
750 | else | |
751 | req |= IEEE80211_HT_CAP_SGI_20; | |
752 | } | |
753 | ||
754 | if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) | |
755 | req |= IEEE80211_HT_CAP_SUP_WIDTH_20_40; | |
756 | ||
757 | if ((sta_cap & req) != req) | |
758 | continue; | |
759 | ||
e9219779 HS |
760 | /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */ |
761 | if (smps == WLAN_HT_CAP_SM_PS_STATIC && | |
762 | minstrel_mcs_groups[i].streams > 1) | |
763 | continue; | |
764 | ||
ec8aa669 FF |
765 | mi->groups[i].supported = |
766 | mcs->rx_mask[minstrel_mcs_groups[i].streams - 1]; | |
4dc217df FF |
767 | |
768 | if (mi->groups[i].supported) | |
769 | n_supported++; | |
ec8aa669 | 770 | } |
4dc217df FF |
771 | |
772 | if (!n_supported) | |
773 | goto use_legacy; | |
774 | ||
775 | return; | |
776 | ||
777 | use_legacy: | |
778 | msp->is_ht = false; | |
779 | memset(&msp->legacy, 0, sizeof(msp->legacy)); | |
780 | msp->legacy.r = msp->ratelist; | |
781 | msp->legacy.sample_table = msp->sample_table; | |
782 | return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy); | |
ec8aa669 FF |
783 | } |
784 | ||
785 | static void | |
786 | minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband, | |
787 | struct ieee80211_sta *sta, void *priv_sta) | |
788 | { | |
64f68e5d | 789 | minstrel_ht_update_caps(priv, sband, sta, priv_sta); |
ec8aa669 FF |
790 | } |
791 | ||
792 | static void | |
793 | minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband, | |
794 | struct ieee80211_sta *sta, void *priv_sta, | |
64f68e5d | 795 | u32 changed) |
ec8aa669 | 796 | { |
64f68e5d | 797 | minstrel_ht_update_caps(priv, sband, sta, priv_sta); |
ec8aa669 FF |
798 | } |
799 | ||
800 | static void * | |
801 | minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp) | |
802 | { | |
803 | struct ieee80211_supported_band *sband; | |
804 | struct minstrel_ht_sta_priv *msp; | |
805 | struct minstrel_priv *mp = priv; | |
806 | struct ieee80211_hw *hw = mp->hw; | |
807 | int max_rates = 0; | |
808 | int i; | |
809 | ||
810 | for (i = 0; i < IEEE80211_NUM_BANDS; i++) { | |
811 | sband = hw->wiphy->bands[i]; | |
812 | if (sband && sband->n_bitrates > max_rates) | |
813 | max_rates = sband->n_bitrates; | |
814 | } | |
815 | ||
472dd35c | 816 | msp = kzalloc(sizeof(*msp), gfp); |
ec8aa669 FF |
817 | if (!msp) |
818 | return NULL; | |
819 | ||
820 | msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp); | |
821 | if (!msp->ratelist) | |
822 | goto error; | |
823 | ||
824 | msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp); | |
825 | if (!msp->sample_table) | |
826 | goto error1; | |
827 | ||
828 | return msp; | |
829 | ||
830 | error1: | |
7e988014 | 831 | kfree(msp->ratelist); |
ec8aa669 FF |
832 | error: |
833 | kfree(msp); | |
834 | return NULL; | |
835 | } | |
836 | ||
837 | static void | |
838 | minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta) | |
839 | { | |
840 | struct minstrel_ht_sta_priv *msp = priv_sta; | |
841 | ||
842 | kfree(msp->sample_table); | |
843 | kfree(msp->ratelist); | |
844 | kfree(msp); | |
845 | } | |
846 | ||
847 | static void * | |
848 | minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) | |
849 | { | |
850 | return mac80211_minstrel.alloc(hw, debugfsdir); | |
851 | } | |
852 | ||
853 | static void | |
854 | minstrel_ht_free(void *priv) | |
855 | { | |
856 | mac80211_minstrel.free(priv); | |
857 | } | |
858 | ||
859 | static struct rate_control_ops mac80211_minstrel_ht = { | |
860 | .name = "minstrel_ht", | |
861 | .tx_status = minstrel_ht_tx_status, | |
862 | .get_rate = minstrel_ht_get_rate, | |
863 | .rate_init = minstrel_ht_rate_init, | |
864 | .rate_update = minstrel_ht_rate_update, | |
865 | .alloc_sta = minstrel_ht_alloc_sta, | |
866 | .free_sta = minstrel_ht_free_sta, | |
867 | .alloc = minstrel_ht_alloc, | |
868 | .free = minstrel_ht_free, | |
869 | #ifdef CONFIG_MAC80211_DEBUGFS | |
870 | .add_sta_debugfs = minstrel_ht_add_sta_debugfs, | |
871 | .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs, | |
872 | #endif | |
873 | }; | |
874 | ||
875 | ||
876 | static void | |
877 | init_sample_table(void) | |
878 | { | |
879 | int col, i, new_idx; | |
880 | u8 rnd[MCS_GROUP_RATES]; | |
881 | ||
882 | memset(sample_table, 0xff, sizeof(sample_table)); | |
883 | for (col = 0; col < SAMPLE_COLUMNS; col++) { | |
884 | for (i = 0; i < MCS_GROUP_RATES; i++) { | |
885 | get_random_bytes(rnd, sizeof(rnd)); | |
886 | new_idx = (i + rnd[i]) % MCS_GROUP_RATES; | |
887 | ||
888 | while (sample_table[col][new_idx] != 0xff) | |
889 | new_idx = (new_idx + 1) % MCS_GROUP_RATES; | |
890 | ||
891 | sample_table[col][new_idx] = i; | |
892 | } | |
893 | } | |
894 | } | |
895 | ||
896 | int __init | |
897 | rc80211_minstrel_ht_init(void) | |
898 | { | |
899 | init_sample_table(); | |
900 | return ieee80211_rate_control_register(&mac80211_minstrel_ht); | |
901 | } | |
902 | ||
903 | void | |
904 | rc80211_minstrel_ht_exit(void) | |
905 | { | |
906 | ieee80211_rate_control_unregister(&mac80211_minstrel_ht); | |
907 | } |