Root/
1 | /* |
2 | * Copyright (C) 2010-2013 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 | |
21 | /* Number of bits for an average sized packet */ |
22 | #define MCS_NBITS (AVG_PKT_SIZE << 3) |
23 | |
24 | /* Number of symbols for a packet with (bps) bits per symbol */ |
25 | #define MCS_NSYMS(bps) ((MCS_NBITS + (bps) - 1) / (bps)) |
26 | |
27 | /* Transmission time (nanoseconds) for a packet containing (syms) symbols */ |
28 | #define MCS_SYMBOL_TIME(sgi, syms) \ |
29 | (sgi ? \ |
30 | ((syms) * 18000 + 4000) / 5 : /* syms * 3.6 us */ \ |
31 | ((syms) * 1000) << 2 /* syms * 4 us */ \ |
32 | ) |
33 | |
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))) |
36 | |
37 | /* |
38 | * Define group sort order: HT40 -> SGI -> #streams |
39 | */ |
40 | #define GROUP_IDX(_streams, _sgi, _ht40) \ |
41 | MINSTREL_MAX_STREAMS * 2 * _ht40 + \ |
42 | MINSTREL_MAX_STREAMS * _sgi + \ |
43 | _streams - 1 |
44 | |
45 | /* MCS rate information for an MCS group */ |
46 | #define MCS_GROUP(_streams, _sgi, _ht40) \ |
47 | [GROUP_IDX(_streams, _sgi, _ht40)] = { \ |
48 | .streams = _streams, \ |
49 | .flags = \ |
50 | (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \ |
51 | (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \ |
52 | .duration = { \ |
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) \ |
61 | } \ |
62 | } |
63 | |
64 | #define CCK_DURATION(_bitrate, _short, _len) \ |
65 | (1000 * (10 /* SIFS */ + \ |
66 | (_short ? 72 + 24 : 144 + 48) + \ |
67 | (8 * (_len + 4) * 10) / (_bitrate))) |
68 | |
69 | #define CCK_ACK_DURATION(_bitrate, _short) \ |
70 | (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) + \ |
71 | CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE)) |
72 | |
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) |
78 | |
79 | #define CCK_GROUP \ |
80 | [MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS] = { \ |
81 | .streams = 0, \ |
82 | .duration = { \ |
83 | CCK_DURATION_LIST(false), \ |
84 | CCK_DURATION_LIST(true) \ |
85 | } \ |
86 | } |
87 | |
88 | /* |
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 |
91 | * use. |
92 | * |
93 | * Sortorder has to be fixed for GROUP_IDX macro to be applicable: |
94 | * HT40 -> SGI -> #streams |
95 | */ |
96 | const struct mcs_group minstrel_mcs_groups[] = { |
97 | MCS_GROUP(1, 0, 0), |
98 | MCS_GROUP(2, 0, 0), |
99 | #if MINSTREL_MAX_STREAMS >= 3 |
100 | MCS_GROUP(3, 0, 0), |
101 | #endif |
102 | |
103 | MCS_GROUP(1, 1, 0), |
104 | MCS_GROUP(2, 1, 0), |
105 | #if MINSTREL_MAX_STREAMS >= 3 |
106 | MCS_GROUP(3, 1, 0), |
107 | #endif |
108 | |
109 | MCS_GROUP(1, 0, 1), |
110 | MCS_GROUP(2, 0, 1), |
111 | #if MINSTREL_MAX_STREAMS >= 3 |
112 | MCS_GROUP(3, 0, 1), |
113 | #endif |
114 | |
115 | MCS_GROUP(1, 1, 1), |
116 | MCS_GROUP(2, 1, 1), |
117 | #if MINSTREL_MAX_STREAMS >= 3 |
118 | MCS_GROUP(3, 1, 1), |
119 | #endif |
120 | |
121 | /* must be last */ |
122 | CCK_GROUP |
123 | }; |
124 | |
125 | #define MINSTREL_CCK_GROUP (ARRAY_SIZE(minstrel_mcs_groups) - 1) |
126 | |
127 | static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly; |
128 | |
129 | static void |
130 | minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi); |
131 | |
132 | /* |
133 | * Look up an MCS group index based on mac80211 rate information |
134 | */ |
135 | static int |
136 | minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate) |
137 | { |
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)); |
141 | } |
142 | |
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) |
146 | { |
147 | int group, idx; |
148 | |
149 | if (rate->flags & IEEE80211_TX_RC_MCS) { |
150 | group = minstrel_ht_get_group_idx(rate); |
151 | idx = rate->idx % 8; |
152 | } else { |
153 | group = MINSTREL_CCK_GROUP; |
154 | |
155 | for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++) |
156 | if (rate->idx == mp->cck_rates[idx]) |
157 | break; |
158 | |
159 | /* short preamble */ |
160 | if (!(mi->groups[group].supported & BIT(idx))) |
161 | idx += 4; |
162 | } |
163 | return &mi->groups[group].rates[idx]; |
164 | } |
165 | |
166 | static inline struct minstrel_rate_stats * |
167 | minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index) |
168 | { |
169 | return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES]; |
170 | } |
171 | |
172 | |
173 | /* |
174 | * Recalculate success probabilities and counters for a rate using EWMA |
175 | */ |
176 | static void |
177 | minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr) |
178 | { |
179 | if (unlikely(mr->attempts > 0)) { |
180 | mr->sample_skipped = 0; |
181 | mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts); |
182 | if (!mr->att_hist) |
183 | mr->probability = mr->cur_prob; |
184 | else |
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; |
189 | } else { |
190 | mr->sample_skipped++; |
191 | } |
192 | mr->last_success = mr->success; |
193 | mr->last_attempts = mr->attempts; |
194 | mr->success = 0; |
195 | mr->attempts = 0; |
196 | } |
197 | |
198 | /* |
199 | * Calculate throughput based on the average A-MPDU length, taking into account |
200 | * the expected number of retransmissions and their expected length |
201 | */ |
202 | static void |
203 | minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate) |
204 | { |
205 | struct minstrel_rate_stats *mr; |
206 | unsigned int nsecs = 0; |
207 | unsigned int tp; |
208 | unsigned int prob; |
209 | |
210 | mr = &mi->groups[group].rates[rate]; |
211 | prob = mr->probability; |
212 | |
213 | if (prob < MINSTREL_FRAC(1, 10)) { |
214 | mr->cur_tp = 0; |
215 | return; |
216 | } |
217 | |
218 | /* |
219 | * For the throughput calculation, limit the probability value to 90% to |
220 | * account for collision related packet error rate fluctuation |
221 | */ |
222 | if (prob > MINSTREL_FRAC(9, 10)) |
223 | prob = MINSTREL_FRAC(9, 10); |
224 | |
225 | if (group != MINSTREL_CCK_GROUP) |
226 | nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len); |
227 | |
228 | nsecs += minstrel_mcs_groups[group].duration[rate]; |
229 | tp = 1000000 * ((prob * 1000) / nsecs); |
230 | |
231 | mr->cur_tp = MINSTREL_TRUNC(tp); |
232 | } |
233 | |
234 | /* |
235 | * Update rate statistics and select new primary rates |
236 | * |
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 |
242 | */ |
243 | static void |
244 | minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) |
245 | { |
246 | struct minstrel_mcs_group_data *mg; |
247 | struct minstrel_rate_stats *mr; |
248 | int cur_prob, cur_prob_tp, cur_tp, cur_tp2; |
249 | int group, i, index; |
250 | bool mi_rates_valid = false; |
251 | |
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); |
255 | mi->ampdu_len = 0; |
256 | mi->ampdu_packets = 0; |
257 | } |
258 | |
259 | mi->sample_slow = 0; |
260 | mi->sample_count = 0; |
261 | |
262 | for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { |
263 | bool mg_rates_valid = false; |
264 | |
265 | cur_prob = 0; |
266 | cur_prob_tp = 0; |
267 | cur_tp = 0; |
268 | cur_tp2 = 0; |
269 | |
270 | mg = &mi->groups[group]; |
271 | if (!mg->supported) |
272 | continue; |
273 | |
274 | mi->sample_count++; |
275 | |
276 | for (i = 0; i < MCS_GROUP_RATES; i++) { |
277 | if (!(mg->supported & BIT(i))) |
278 | continue; |
279 | |
280 | index = MCS_GROUP_RATES * group + i; |
281 | |
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; |
290 | } |
291 | mg_rates_valid = true; |
292 | } |
293 | |
294 | mr = &mg->rates[i]; |
295 | mr->retry_updated = false; |
296 | minstrel_calc_rate_ewma(mr); |
297 | minstrel_ht_calc_tp(mi, group, i); |
298 | |
299 | if (!mr->cur_tp) |
300 | continue; |
301 | |
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; |
307 | } |
308 | |
309 | if (mr->cur_tp > cur_tp) { |
310 | swap(index, mg->max_tp_rate); |
311 | cur_tp = mr->cur_tp; |
312 | mr = minstrel_get_ratestats(mi, index); |
313 | } |
314 | |
315 | if (index >= mg->max_tp_rate) |
316 | continue; |
317 | |
318 | if (mr->cur_tp > cur_tp2) { |
319 | mg->max_tp_rate2 = index; |
320 | cur_tp2 = mr->cur_tp; |
321 | } |
322 | } |
323 | } |
324 | |
325 | /* try to sample all available rates during each interval */ |
326 | mi->sample_count *= 8; |
327 | |
328 | cur_prob = 0; |
329 | cur_prob_tp = 0; |
330 | cur_tp = 0; |
331 | cur_tp2 = 0; |
332 | for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { |
333 | mg = &mi->groups[group]; |
334 | if (!mg->supported) |
335 | continue; |
336 | |
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; |
340 | cur_tp2 = cur_tp; |
341 | mi->max_tp_rate = mg->max_tp_rate; |
342 | cur_tp = mr->cur_tp; |
343 | mi->max_prob_streams = minstrel_mcs_groups[group].streams - 1; |
344 | } |
345 | |
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; |
350 | } |
351 | } |
352 | |
353 | if (mi->max_prob_streams < 1) |
354 | mi->max_prob_streams = 1; |
355 | |
356 | for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { |
357 | mg = &mi->groups[group]; |
358 | if (!mg->supported) |
359 | continue; |
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; |
366 | } |
367 | } |
368 | |
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; |
375 | } |
376 | #endif |
377 | |
378 | mi->stats_update = jiffies; |
379 | } |
380 | |
381 | static bool |
382 | minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate) |
383 | { |
384 | if (rate->idx < 0) |
385 | return false; |
386 | |
387 | if (!rate->count) |
388 | return false; |
389 | |
390 | if (rate->flags & IEEE80211_TX_RC_MCS) |
391 | return true; |
392 | |
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]; |
397 | } |
398 | |
399 | static void |
400 | minstrel_next_sample_idx(struct minstrel_ht_sta *mi) |
401 | { |
402 | struct minstrel_mcs_group_data *mg; |
403 | |
404 | for (;;) { |
405 | mi->sample_group++; |
406 | mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups); |
407 | mg = &mi->groups[mi->sample_group]; |
408 | |
409 | if (!mg->supported) |
410 | continue; |
411 | |
412 | if (++mg->index >= MCS_GROUP_RATES) { |
413 | mg->index = 0; |
414 | if (++mg->column >= ARRAY_SIZE(sample_table)) |
415 | mg->column = 0; |
416 | } |
417 | break; |
418 | } |
419 | } |
420 | |
421 | static void |
422 | minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx, |
423 | bool primary) |
424 | { |
425 | int group, orig_group; |
426 | |
427 | orig_group = group = *idx / MCS_GROUP_RATES; |
428 | while (group > 0) { |
429 | group--; |
430 | |
431 | if (!mi->groups[group].supported) |
432 | continue; |
433 | |
434 | if (minstrel_mcs_groups[group].streams > |
435 | minstrel_mcs_groups[orig_group].streams) |
436 | continue; |
437 | |
438 | if (primary) |
439 | *idx = mi->groups[group].max_tp_rate; |
440 | else |
441 | *idx = mi->groups[group].max_tp_rate2; |
442 | break; |
443 | } |
444 | } |
445 | |
446 | static void |
447 | minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb) |
448 | { |
449 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; |
450 | struct sta_info *sta = container_of(pubsta, struct sta_info, sta); |
451 | u16 tid; |
452 | |
453 | if (unlikely(!ieee80211_is_data_qos(hdr->frame_control))) |
454 | return; |
455 | |
456 | if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE))) |
457 | return; |
458 | |
459 | tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; |
460 | if (likely(sta->ampdu_mlme.tid_tx[tid])) |
461 | return; |
462 | |
463 | if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO) |
464 | return; |
465 | |
466 | ieee80211_start_tx_ba_session(pubsta, tid, 5000); |
467 | } |
468 | |
469 | static void |
470 | minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, |
471 | struct ieee80211_sta *sta, void *priv_sta, |
472 | struct sk_buff *skb) |
473 | { |
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; |
481 | int i; |
482 | |
483 | if (!msp->is_ht) |
484 | return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb); |
485 | |
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)) |
489 | return; |
490 | |
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; |
495 | } |
496 | |
497 | mi->ampdu_packets++; |
498 | mi->ampdu_len += info->status.ampdu_len; |
499 | |
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; |
503 | mi->sample_count--; |
504 | } |
505 | |
506 | if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) |
507 | mi->sample_packets += info->status.ampdu_len; |
508 | |
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]); |
513 | |
514 | rate = minstrel_ht_get_stats(mp, mi, &ar[i]); |
515 | |
516 | if (last) |
517 | rate->success += info->status.ampdu_ack_len; |
518 | |
519 | rate->attempts += ar[i].count * info->status.ampdu_len; |
520 | } |
521 | |
522 | /* |
523 | * check for sudden death of spatial multiplexing, |
524 | * downgrade to a lower number of streams if necessary. |
525 | */ |
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); |
531 | update = true; |
532 | } |
533 | |
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); |
539 | update = true; |
540 | } |
541 | |
542 | if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) { |
543 | update = true; |
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); |
548 | } |
549 | |
550 | if (update) |
551 | minstrel_ht_update_rates(mp, mi); |
552 | } |
553 | |
554 | static void |
555 | minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, |
556 | int index) |
557 | { |
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; |
566 | |
567 | mr = minstrel_get_ratestats(mi, index); |
568 | if (mr->probability < MINSTREL_FRAC(1, 10)) { |
569 | mr->retry_count = 1; |
570 | mr->retry_count_rtscts = 1; |
571 | return; |
572 | } |
573 | |
574 | mr->retry_count = 2; |
575 | mr->retry_count_rtscts = 2; |
576 | mr->retry_updated = true; |
577 | |
578 | group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; |
579 | tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000; |
580 | |
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); |
586 | |
587 | if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) { |
588 | overhead = mi->overhead; |
589 | overhead_rtscts = mi->overhead_rtscts; |
590 | } |
591 | |
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); |
595 | |
596 | /* See how many more tries we can fit inside segment size */ |
597 | do { |
598 | /* Contention time for this try */ |
599 | ctime = (t_slot * cw) >> 1; |
600 | cw = min((cw << 1) | 1, mp->cw_max); |
601 | |
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; |
605 | |
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)); |
610 | } |
611 | |
612 | |
613 | static void |
614 | minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, |
615 | struct ieee80211_sta_rates *ratetbl, int offset, int index) |
616 | { |
617 | const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; |
618 | struct minstrel_rate_stats *mr; |
619 | u8 idx; |
620 | u16 flags; |
621 | |
622 | mr = minstrel_get_ratestats(mi, index); |
623 | if (!mr->retry_updated) |
624 | minstrel_calc_retransmit(mp, mi, index); |
625 | |
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; |
630 | } else { |
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; |
634 | } |
635 | |
636 | if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) { |
637 | idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)]; |
638 | flags = 0; |
639 | } else { |
640 | idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8; |
641 | flags = IEEE80211_TX_RC_MCS | group->flags; |
642 | } |
643 | |
644 | if (offset > 0) { |
645 | ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts; |
646 | flags |= IEEE80211_TX_RC_USE_RTS_CTS; |
647 | } |
648 | |
649 | ratetbl->rate[offset].idx = idx; |
650 | ratetbl->rate[offset].flags = flags; |
651 | } |
652 | |
653 | static void |
654 | minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) |
655 | { |
656 | struct ieee80211_sta_rates *rates; |
657 | int i = 0; |
658 | |
659 | rates = kzalloc(sizeof(*rates), GFP_ATOMIC); |
660 | if (!rates) |
661 | return; |
662 | |
663 | /* Start with max_tp_rate */ |
664 | minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate); |
665 | |
666 | if (mp->hw->max_rates >= 3) { |
667 | /* At least 3 tx rates supported, use max_tp_rate2 next */ |
668 | minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate2); |
669 | } |
670 | |
671 | if (mp->hw->max_rates >= 2) { |
672 | /* |
673 | * At least 2 tx rates supported, use max_prob_rate next */ |
674 | minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate); |
675 | } |
676 | |
677 | rates->rate[i].idx = -1; |
678 | rate_control_set_rates(mp->hw, mi->sta, rates); |
679 | } |
680 | |
681 | static inline int |
682 | minstrel_get_duration(int index) |
683 | { |
684 | const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; |
685 | return group->duration[index % MCS_GROUP_RATES]; |
686 | } |
687 | |
688 | static int |
689 | minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) |
690 | { |
691 | struct minstrel_rate_stats *mr; |
692 | struct minstrel_mcs_group_data *mg; |
693 | unsigned int sample_dur, sample_group; |
694 | int sample_idx = 0; |
695 | |
696 | if (mi->sample_wait > 0) { |
697 | mi->sample_wait--; |
698 | return -1; |
699 | } |
700 | |
701 | if (!mi->sample_tries) |
702 | return -1; |
703 | |
704 | sample_group = mi->sample_group; |
705 | mg = &mi->groups[sample_group]; |
706 | sample_idx = sample_table[mg->column][mg->index]; |
707 | minstrel_next_sample_idx(mi); |
708 | |
709 | if (!(mg->supported & BIT(sample_idx))) |
710 | return -1; |
711 | |
712 | mr = &mg->rates[sample_idx]; |
713 | sample_idx += sample_group * MCS_GROUP_RATES; |
714 | |
715 | /* |
716 | * Sampling might add some overhead (RTS, no aggregation) |
717 | * to the frame. Hence, don't use sampling for the currently |
718 | * used rates. |
719 | */ |
720 | if (sample_idx == mi->max_tp_rate || |
721 | sample_idx == mi->max_tp_rate2 || |
722 | sample_idx == mi->max_prob_rate) |
723 | return -1; |
724 | |
725 | /* |
726 | * Do not sample if the probability is already higher than 95% |
727 | * to avoid wasting airtime. |
728 | */ |
729 | if (mr->probability > MINSTREL_FRAC(95, 100)) |
730 | return -1; |
731 | |
732 | /* |
733 | * Make sure that lower rates get sampled only occasionally, |
734 | * if the link is working perfectly. |
735 | */ |
736 | sample_dur = minstrel_get_duration(sample_idx); |
737 | if (sample_dur >= minstrel_get_duration(mi->max_tp_rate2) && |
738 | (mi->max_prob_streams < |
739 | minstrel_mcs_groups[sample_group].streams || |
740 | sample_dur >= minstrel_get_duration(mi->max_prob_rate))) { |
741 | if (mr->sample_skipped < 20) |
742 | return -1; |
743 | |
744 | if (mi->sample_slow++ > 2) |
745 | return -1; |
746 | } |
747 | mi->sample_tries--; |
748 | |
749 | return sample_idx; |
750 | } |
751 | |
752 | static void |
753 | minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp, |
754 | struct minstrel_ht_sta *mi, bool val) |
755 | { |
756 | u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported; |
757 | |
758 | if (!supported || !mi->cck_supported_short) |
759 | return; |
760 | |
761 | if (supported & (mi->cck_supported_short << (val * 4))) |
762 | return; |
763 | |
764 | supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4); |
765 | mi->groups[MINSTREL_CCK_GROUP].supported = supported; |
766 | } |
767 | |
768 | static void |
769 | minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, |
770 | struct ieee80211_tx_rate_control *txrc) |
771 | { |
772 | const struct mcs_group *sample_group; |
773 | struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); |
774 | struct ieee80211_tx_rate *rate = &info->status.rates[0]; |
775 | struct minstrel_ht_sta_priv *msp = priv_sta; |
776 | struct minstrel_ht_sta *mi = &msp->ht; |
777 | struct minstrel_priv *mp = priv; |
778 | int sample_idx; |
779 | |
780 | if (rate_control_send_low(sta, priv_sta, txrc)) |
781 | return; |
782 | |
783 | if (!msp->is_ht) |
784 | return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc); |
785 | |
786 | info->flags |= mi->tx_flags; |
787 | minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble); |
788 | |
789 | #ifdef CONFIG_MAC80211_DEBUGFS |
790 | if (mp->fixed_rate_idx != -1) |
791 | return; |
792 | #endif |
793 | |
794 | /* Don't use EAPOL frames for sampling on non-mrr hw */ |
795 | if (mp->hw->max_rates == 1 && |
796 | (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO)) |
797 | sample_idx = -1; |
798 | else |
799 | sample_idx = minstrel_get_sample_rate(mp, mi); |
800 | |
801 | mi->total_packets++; |
802 | |
803 | /* wraparound */ |
804 | if (mi->total_packets == ~0) { |
805 | mi->total_packets = 0; |
806 | mi->sample_packets = 0; |
807 | } |
808 | |
809 | if (sample_idx < 0) |
810 | return; |
811 | |
812 | sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES]; |
813 | info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; |
814 | rate->count = 1; |
815 | |
816 | if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) { |
817 | int idx = sample_idx % ARRAY_SIZE(mp->cck_rates); |
818 | rate->idx = mp->cck_rates[idx]; |
819 | rate->flags = 0; |
820 | return; |
821 | } |
822 | |
823 | rate->idx = sample_idx % MCS_GROUP_RATES + |
824 | (sample_group->streams - 1) * 8; |
825 | rate->flags = IEEE80211_TX_RC_MCS | sample_group->flags; |
826 | } |
827 | |
828 | static void |
829 | minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, |
830 | struct ieee80211_supported_band *sband, |
831 | struct ieee80211_sta *sta) |
832 | { |
833 | int i; |
834 | |
835 | if (sband->band != IEEE80211_BAND_2GHZ) |
836 | return; |
837 | |
838 | if (!(mp->hw->flags & IEEE80211_HW_SUPPORTS_HT_CCK_RATES)) |
839 | return; |
840 | |
841 | mi->cck_supported = 0; |
842 | mi->cck_supported_short = 0; |
843 | for (i = 0; i < 4; i++) { |
844 | if (!rate_supported(sta, sband->band, mp->cck_rates[i])) |
845 | continue; |
846 | |
847 | mi->cck_supported |= BIT(i); |
848 | if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE) |
849 | mi->cck_supported_short |= BIT(i); |
850 | } |
851 | |
852 | mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported; |
853 | } |
854 | |
855 | static void |
856 | minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, |
857 | struct cfg80211_chan_def *chandef, |
858 | struct ieee80211_sta *sta, void *priv_sta) |
859 | { |
860 | struct minstrel_priv *mp = priv; |
861 | struct minstrel_ht_sta_priv *msp = priv_sta; |
862 | struct minstrel_ht_sta *mi = &msp->ht; |
863 | struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs; |
864 | u16 sta_cap = sta->ht_cap.cap; |
865 | int n_supported = 0; |
866 | int ack_dur; |
867 | int stbc; |
868 | int i; |
869 | |
870 | /* fall back to the old minstrel for legacy stations */ |
871 | if (!sta->ht_cap.ht_supported) |
872 | goto use_legacy; |
873 | |
874 | BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != |
875 | MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1); |
876 | |
877 | msp->is_ht = true; |
878 | memset(mi, 0, sizeof(*mi)); |
879 | |
880 | mi->sta = sta; |
881 | mi->stats_update = jiffies; |
882 | |
883 | ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0); |
884 | mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0); |
885 | mi->overhead += ack_dur; |
886 | mi->overhead_rtscts = mi->overhead + 2 * ack_dur; |
887 | |
888 | mi->avg_ampdu_len = MINSTREL_FRAC(1, 1); |
889 | |
890 | /* When using MRR, sample more on the first attempt, without delay */ |
891 | if (mp->has_mrr) { |
892 | mi->sample_count = 16; |
893 | mi->sample_wait = 0; |
894 | } else { |
895 | mi->sample_count = 8; |
896 | mi->sample_wait = 8; |
897 | } |
898 | mi->sample_tries = 4; |
899 | |
900 | stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >> |
901 | IEEE80211_HT_CAP_RX_STBC_SHIFT; |
902 | mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT; |
903 | |
904 | if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING) |
905 | mi->tx_flags |= IEEE80211_TX_CTL_LDPC; |
906 | |
907 | for (i = 0; i < ARRAY_SIZE(mi->groups); i++) { |
908 | mi->groups[i].supported = 0; |
909 | if (i == MINSTREL_CCK_GROUP) { |
910 | minstrel_ht_update_cck(mp, mi, sband, sta); |
911 | continue; |
912 | } |
913 | |
914 | if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) { |
915 | if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) { |
916 | if (!(sta_cap & IEEE80211_HT_CAP_SGI_40)) |
917 | continue; |
918 | } else { |
919 | if (!(sta_cap & IEEE80211_HT_CAP_SGI_20)) |
920 | continue; |
921 | } |
922 | } |
923 | |
924 | if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH && |
925 | sta->bandwidth < IEEE80211_STA_RX_BW_40) |
926 | continue; |
927 | |
928 | /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */ |
929 | if (sta->smps_mode == IEEE80211_SMPS_STATIC && |
930 | minstrel_mcs_groups[i].streams > 1) |
931 | continue; |
932 | |
933 | mi->groups[i].supported = |
934 | mcs->rx_mask[minstrel_mcs_groups[i].streams - 1]; |
935 | |
936 | if (mi->groups[i].supported) |
937 | n_supported++; |
938 | } |
939 | |
940 | if (!n_supported) |
941 | goto use_legacy; |
942 | |
943 | /* create an initial rate table with the lowest supported rates */ |
944 | minstrel_ht_update_stats(mp, mi); |
945 | minstrel_ht_update_rates(mp, mi); |
946 | |
947 | return; |
948 | |
949 | use_legacy: |
950 | msp->is_ht = false; |
951 | memset(&msp->legacy, 0, sizeof(msp->legacy)); |
952 | msp->legacy.r = msp->ratelist; |
953 | msp->legacy.sample_table = msp->sample_table; |
954 | return mac80211_minstrel.rate_init(priv, sband, chandef, sta, |
955 | &msp->legacy); |
956 | } |
957 | |
958 | static void |
959 | minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband, |
960 | struct cfg80211_chan_def *chandef, |
961 | struct ieee80211_sta *sta, void *priv_sta) |
962 | { |
963 | minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta); |
964 | } |
965 | |
966 | static void |
967 | minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband, |
968 | struct cfg80211_chan_def *chandef, |
969 | struct ieee80211_sta *sta, void *priv_sta, |
970 | u32 changed) |
971 | { |
972 | minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta); |
973 | } |
974 | |
975 | static void * |
976 | minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp) |
977 | { |
978 | struct ieee80211_supported_band *sband; |
979 | struct minstrel_ht_sta_priv *msp; |
980 | struct minstrel_priv *mp = priv; |
981 | struct ieee80211_hw *hw = mp->hw; |
982 | int max_rates = 0; |
983 | int i; |
984 | |
985 | for (i = 0; i < IEEE80211_NUM_BANDS; i++) { |
986 | sband = hw->wiphy->bands[i]; |
987 | if (sband && sband->n_bitrates > max_rates) |
988 | max_rates = sband->n_bitrates; |
989 | } |
990 | |
991 | msp = kzalloc(sizeof(*msp), gfp); |
992 | if (!msp) |
993 | return NULL; |
994 | |
995 | msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp); |
996 | if (!msp->ratelist) |
997 | goto error; |
998 | |
999 | msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp); |
1000 | if (!msp->sample_table) |
1001 | goto error1; |
1002 | |
1003 | return msp; |
1004 | |
1005 | error1: |
1006 | kfree(msp->ratelist); |
1007 | error: |
1008 | kfree(msp); |
1009 | return NULL; |
1010 | } |
1011 | |
1012 | static void |
1013 | minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta) |
1014 | { |
1015 | struct minstrel_ht_sta_priv *msp = priv_sta; |
1016 | |
1017 | kfree(msp->sample_table); |
1018 | kfree(msp->ratelist); |
1019 | kfree(msp); |
1020 | } |
1021 | |
1022 | static void * |
1023 | minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) |
1024 | { |
1025 | return mac80211_minstrel.alloc(hw, debugfsdir); |
1026 | } |
1027 | |
1028 | static void |
1029 | minstrel_ht_free(void *priv) |
1030 | { |
1031 | mac80211_minstrel.free(priv); |
1032 | } |
1033 | |
1034 | static const struct rate_control_ops mac80211_minstrel_ht = { |
1035 | .name = "minstrel_ht", |
1036 | .tx_status = minstrel_ht_tx_status, |
1037 | .get_rate = minstrel_ht_get_rate, |
1038 | .rate_init = minstrel_ht_rate_init, |
1039 | .rate_update = minstrel_ht_rate_update, |
1040 | .alloc_sta = minstrel_ht_alloc_sta, |
1041 | .free_sta = minstrel_ht_free_sta, |
1042 | .alloc = minstrel_ht_alloc, |
1043 | .free = minstrel_ht_free, |
1044 | #ifdef CONFIG_MAC80211_DEBUGFS |
1045 | .add_sta_debugfs = minstrel_ht_add_sta_debugfs, |
1046 | .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs, |
1047 | #endif |
1048 | }; |
1049 | |
1050 | |
1051 | static void __init init_sample_table(void) |
1052 | { |
1053 | int col, i, new_idx; |
1054 | u8 rnd[MCS_GROUP_RATES]; |
1055 | |
1056 | memset(sample_table, 0xff, sizeof(sample_table)); |
1057 | for (col = 0; col < SAMPLE_COLUMNS; col++) { |
1058 | prandom_bytes(rnd, sizeof(rnd)); |
1059 | for (i = 0; i < MCS_GROUP_RATES; i++) { |
1060 | new_idx = (i + rnd[i]) % MCS_GROUP_RATES; |
1061 | while (sample_table[col][new_idx] != 0xff) |
1062 | new_idx = (new_idx + 1) % MCS_GROUP_RATES; |
1063 | |
1064 | sample_table[col][new_idx] = i; |
1065 | } |
1066 | } |
1067 | } |
1068 | |
1069 | int __init |
1070 | rc80211_minstrel_ht_init(void) |
1071 | { |
1072 | init_sample_table(); |
1073 | return ieee80211_rate_control_register(&mac80211_minstrel_ht); |
1074 | } |
1075 | |
1076 | void |
1077 | rc80211_minstrel_ht_exit(void) |
1078 | { |
1079 | ieee80211_rate_control_unregister(&mac80211_minstrel_ht); |
1080 | } |
1081 |
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