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ec8aa669 | 1 | /* |
a0497f9f | 2 | * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org> |
ec8aa669 FF |
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 | ||
a0497f9f FF |
66 | #define CCK_DURATION(_bitrate, _short, _len) \ |
67 | (10 /* SIFS */ + \ | |
68 | (_short ? 72 + 24 : 144 + 48 ) + \ | |
69 | (8 * (_len + 4) * 10) / (_bitrate)) | |
70 | ||
71 | #define CCK_ACK_DURATION(_bitrate, _short) \ | |
72 | (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) + \ | |
73 | CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE)) | |
74 | ||
75 | #define CCK_DURATION_LIST(_short) \ | |
76 | CCK_ACK_DURATION(10, _short), \ | |
77 | CCK_ACK_DURATION(20, _short), \ | |
78 | CCK_ACK_DURATION(55, _short), \ | |
79 | CCK_ACK_DURATION(110, _short) | |
80 | ||
81 | #define CCK_GROUP \ | |
82 | [MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS] = { \ | |
83 | .streams = 0, \ | |
84 | .duration = { \ | |
85 | CCK_DURATION_LIST(false), \ | |
86 | CCK_DURATION_LIST(true) \ | |
87 | } \ | |
88 | } | |
89 | ||
ec8aa669 FF |
90 | /* |
91 | * To enable sufficiently targeted rate sampling, MCS rates are divided into | |
92 | * groups, based on the number of streams and flags (HT40, SGI) that they | |
93 | * use. | |
a5f69d94 HS |
94 | * |
95 | * Sortorder has to be fixed for GROUP_IDX macro to be applicable: | |
96 | * HT40 -> SGI -> #streams | |
ec8aa669 FF |
97 | */ |
98 | const struct mcs_group minstrel_mcs_groups[] = { | |
99 | MCS_GROUP(1, 0, 0), | |
100 | MCS_GROUP(2, 0, 0), | |
101 | #if MINSTREL_MAX_STREAMS >= 3 | |
102 | MCS_GROUP(3, 0, 0), | |
103 | #endif | |
104 | ||
105 | MCS_GROUP(1, 1, 0), | |
106 | MCS_GROUP(2, 1, 0), | |
107 | #if MINSTREL_MAX_STREAMS >= 3 | |
108 | MCS_GROUP(3, 1, 0), | |
109 | #endif | |
110 | ||
111 | MCS_GROUP(1, 0, 1), | |
112 | MCS_GROUP(2, 0, 1), | |
113 | #if MINSTREL_MAX_STREAMS >= 3 | |
114 | MCS_GROUP(3, 0, 1), | |
115 | #endif | |
116 | ||
117 | MCS_GROUP(1, 1, 1), | |
118 | MCS_GROUP(2, 1, 1), | |
119 | #if MINSTREL_MAX_STREAMS >= 3 | |
120 | MCS_GROUP(3, 1, 1), | |
121 | #endif | |
a0497f9f FF |
122 | |
123 | /* must be last */ | |
124 | CCK_GROUP | |
ec8aa669 FF |
125 | }; |
126 | ||
a0497f9f FF |
127 | #define MINSTREL_CCK_GROUP (ARRAY_SIZE(minstrel_mcs_groups) - 1) |
128 | ||
ec8aa669 FF |
129 | static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES]; |
130 | ||
131 | /* | |
132 | * Perform EWMA (Exponentially Weighted Moving Average) calculation | |
133 | */ | |
134 | static int | |
135 | minstrel_ewma(int old, int new, int weight) | |
136 | { | |
137 | return (new * (100 - weight) + old * weight) / 100; | |
138 | } | |
139 | ||
140 | /* | |
141 | * Look up an MCS group index based on mac80211 rate information | |
142 | */ | |
143 | static int | |
144 | minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate) | |
145 | { | |
a5f69d94 HS |
146 | return GROUP_IDX((rate->idx / MCS_GROUP_RATES) + 1, |
147 | !!(rate->flags & IEEE80211_TX_RC_SHORT_GI), | |
148 | !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH)); | |
ec8aa669 FF |
149 | } |
150 | ||
a0497f9f FF |
151 | static struct minstrel_rate_stats * |
152 | minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, | |
153 | struct ieee80211_tx_rate *rate) | |
154 | { | |
155 | int group, idx; | |
156 | ||
157 | if (rate->flags & IEEE80211_TX_RC_MCS) { | |
158 | group = minstrel_ht_get_group_idx(rate); | |
159 | idx = rate->idx % MCS_GROUP_RATES; | |
160 | } else { | |
161 | group = MINSTREL_CCK_GROUP; | |
162 | ||
163 | for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++) | |
164 | if (rate->idx == mp->cck_rates[idx]) | |
165 | break; | |
166 | ||
167 | /* short preamble */ | |
168 | if (!(mi->groups[group].supported & BIT(idx))) | |
169 | idx += 4; | |
170 | } | |
171 | return &mi->groups[group].rates[idx]; | |
172 | } | |
173 | ||
ec8aa669 FF |
174 | static inline struct minstrel_rate_stats * |
175 | minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index) | |
176 | { | |
177 | return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES]; | |
178 | } | |
179 | ||
180 | ||
181 | /* | |
182 | * Recalculate success probabilities and counters for a rate using EWMA | |
183 | */ | |
184 | static void | |
6048d763 | 185 | minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr) |
ec8aa669 FF |
186 | { |
187 | if (unlikely(mr->attempts > 0)) { | |
188 | mr->sample_skipped = 0; | |
189 | mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts); | |
190 | if (!mr->att_hist) | |
191 | mr->probability = mr->cur_prob; | |
192 | else | |
193 | mr->probability = minstrel_ewma(mr->probability, | |
194 | mr->cur_prob, EWMA_LEVEL); | |
195 | mr->att_hist += mr->attempts; | |
196 | mr->succ_hist += mr->success; | |
197 | } else { | |
198 | mr->sample_skipped++; | |
199 | } | |
200 | mr->last_success = mr->success; | |
201 | mr->last_attempts = mr->attempts; | |
202 | mr->success = 0; | |
203 | mr->attempts = 0; | |
204 | } | |
205 | ||
206 | /* | |
207 | * Calculate throughput based on the average A-MPDU length, taking into account | |
208 | * the expected number of retransmissions and their expected length | |
209 | */ | |
210 | static void | |
6048d763 | 211 | minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate) |
ec8aa669 FF |
212 | { |
213 | struct minstrel_rate_stats *mr; | |
a0497f9f | 214 | unsigned int usecs = 0; |
ec8aa669 FF |
215 | |
216 | mr = &mi->groups[group].rates[rate]; | |
217 | ||
218 | if (mr->probability < MINSTREL_FRAC(1, 10)) { | |
219 | mr->cur_tp = 0; | |
220 | return; | |
221 | } | |
222 | ||
a0497f9f FF |
223 | if (group != MINSTREL_CCK_GROUP) |
224 | usecs = mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len); | |
225 | ||
ec8aa669 FF |
226 | usecs += minstrel_mcs_groups[group].duration[rate]; |
227 | mr->cur_tp = MINSTREL_TRUNC((1000000 / usecs) * mr->probability); | |
228 | } | |
229 | ||
230 | /* | |
231 | * Update rate statistics and select new primary rates | |
232 | * | |
233 | * Rules for rate selection: | |
234 | * - max_prob_rate must use only one stream, as a tradeoff between delivery | |
235 | * probability and throughput during strong fluctuations | |
236 | * - as long as the max prob rate has a probability of more than 3/4, pick | |
237 | * higher throughput rates, even if the probablity is a bit lower | |
238 | */ | |
239 | static void | |
240 | minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) | |
241 | { | |
242 | struct minstrel_mcs_group_data *mg; | |
243 | struct minstrel_rate_stats *mr; | |
244 | int cur_prob, cur_prob_tp, cur_tp, cur_tp2; | |
245 | int group, i, index; | |
246 | ||
247 | if (mi->ampdu_packets > 0) { | |
248 | mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len, | |
249 | MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL); | |
250 | mi->ampdu_len = 0; | |
251 | mi->ampdu_packets = 0; | |
252 | } | |
253 | ||
254 | mi->sample_slow = 0; | |
255 | mi->sample_count = 0; | |
256 | mi->max_tp_rate = 0; | |
257 | mi->max_tp_rate2 = 0; | |
258 | mi->max_prob_rate = 0; | |
259 | ||
260 | for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { | |
261 | cur_prob = 0; | |
262 | cur_prob_tp = 0; | |
263 | cur_tp = 0; | |
264 | cur_tp2 = 0; | |
265 | ||
266 | mg = &mi->groups[group]; | |
267 | if (!mg->supported) | |
268 | continue; | |
269 | ||
270 | mg->max_tp_rate = 0; | |
271 | mg->max_tp_rate2 = 0; | |
272 | mg->max_prob_rate = 0; | |
273 | mi->sample_count++; | |
274 | ||
275 | for (i = 0; i < MCS_GROUP_RATES; i++) { | |
276 | if (!(mg->supported & BIT(i))) | |
277 | continue; | |
278 | ||
279 | mr = &mg->rates[i]; | |
280 | mr->retry_updated = false; | |
281 | index = MCS_GROUP_RATES * group + i; | |
6048d763 PK |
282 | minstrel_calc_rate_ewma(mr); |
283 | minstrel_ht_calc_tp(mi, group, i); | |
ec8aa669 FF |
284 | |
285 | if (!mr->cur_tp) | |
286 | continue; | |
287 | ||
ec8aa669 FF |
288 | if ((mr->cur_tp > cur_prob_tp && mr->probability > |
289 | MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) { | |
290 | mg->max_prob_rate = index; | |
291 | cur_prob = mr->probability; | |
009271f9 | 292 | cur_prob_tp = mr->cur_tp; |
ec8aa669 FF |
293 | } |
294 | ||
295 | if (mr->cur_tp > cur_tp) { | |
296 | swap(index, mg->max_tp_rate); | |
297 | cur_tp = mr->cur_tp; | |
298 | mr = minstrel_get_ratestats(mi, index); | |
299 | } | |
300 | ||
301 | if (index >= mg->max_tp_rate) | |
302 | continue; | |
303 | ||
304 | if (mr->cur_tp > cur_tp2) { | |
305 | mg->max_tp_rate2 = index; | |
306 | cur_tp2 = mr->cur_tp; | |
307 | } | |
308 | } | |
309 | } | |
310 | ||
25985edc | 311 | /* try to sample up to half of the available rates during each interval */ |
ec8aa669 FF |
312 | mi->sample_count *= 4; |
313 | ||
314 | cur_prob = 0; | |
315 | cur_prob_tp = 0; | |
316 | cur_tp = 0; | |
317 | cur_tp2 = 0; | |
318 | for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { | |
319 | mg = &mi->groups[group]; | |
320 | if (!mg->supported) | |
321 | continue; | |
322 | ||
323 | mr = minstrel_get_ratestats(mi, mg->max_prob_rate); | |
324 | if (cur_prob_tp < mr->cur_tp && | |
325 | minstrel_mcs_groups[group].streams == 1) { | |
326 | mi->max_prob_rate = mg->max_prob_rate; | |
327 | cur_prob = mr->cur_prob; | |
009271f9 | 328 | cur_prob_tp = mr->cur_tp; |
ec8aa669 FF |
329 | } |
330 | ||
331 | mr = minstrel_get_ratestats(mi, mg->max_tp_rate); | |
332 | if (cur_tp < mr->cur_tp) { | |
89888e36 LB |
333 | mi->max_tp_rate2 = mi->max_tp_rate; |
334 | cur_tp2 = cur_tp; | |
ec8aa669 FF |
335 | mi->max_tp_rate = mg->max_tp_rate; |
336 | cur_tp = mr->cur_tp; | |
337 | } | |
338 | ||
339 | mr = minstrel_get_ratestats(mi, mg->max_tp_rate2); | |
340 | if (cur_tp2 < mr->cur_tp) { | |
341 | mi->max_tp_rate2 = mg->max_tp_rate2; | |
342 | cur_tp2 = mr->cur_tp; | |
343 | } | |
344 | } | |
345 | ||
346 | mi->stats_update = jiffies; | |
347 | } | |
348 | ||
349 | static bool | |
a0497f9f | 350 | minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate) |
ec8aa669 | 351 | { |
b79296be | 352 | if (rate->idx < 0) |
ec8aa669 FF |
353 | return false; |
354 | ||
b79296be | 355 | if (!rate->count) |
ec8aa669 FF |
356 | return false; |
357 | ||
a0497f9f FF |
358 | if (rate->flags & IEEE80211_TX_RC_MCS) |
359 | return true; | |
360 | ||
361 | return rate->idx == mp->cck_rates[0] || | |
362 | rate->idx == mp->cck_rates[1] || | |
363 | rate->idx == mp->cck_rates[2] || | |
364 | rate->idx == mp->cck_rates[3]; | |
ec8aa669 FF |
365 | } |
366 | ||
367 | static void | |
368 | minstrel_next_sample_idx(struct minstrel_ht_sta *mi) | |
369 | { | |
370 | struct minstrel_mcs_group_data *mg; | |
371 | ||
372 | for (;;) { | |
373 | mi->sample_group++; | |
374 | mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups); | |
375 | mg = &mi->groups[mi->sample_group]; | |
376 | ||
377 | if (!mg->supported) | |
378 | continue; | |
379 | ||
380 | if (++mg->index >= MCS_GROUP_RATES) { | |
381 | mg->index = 0; | |
382 | if (++mg->column >= ARRAY_SIZE(sample_table)) | |
383 | mg->column = 0; | |
384 | } | |
385 | break; | |
386 | } | |
387 | } | |
388 | ||
389 | static void | |
d5ece215 JL |
390 | minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx, |
391 | bool primary) | |
ec8aa669 FF |
392 | { |
393 | int group, orig_group; | |
394 | ||
395 | orig_group = group = *idx / MCS_GROUP_RATES; | |
396 | while (group > 0) { | |
397 | group--; | |
398 | ||
399 | if (!mi->groups[group].supported) | |
400 | continue; | |
401 | ||
402 | if (minstrel_mcs_groups[group].streams > | |
403 | minstrel_mcs_groups[orig_group].streams) | |
404 | continue; | |
405 | ||
406 | if (primary) | |
407 | *idx = mi->groups[group].max_tp_rate; | |
408 | else | |
409 | *idx = mi->groups[group].max_tp_rate2; | |
410 | break; | |
411 | } | |
412 | } | |
413 | ||
414 | static void | |
6048d763 | 415 | minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb) |
ec8aa669 FF |
416 | { |
417 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; | |
418 | struct sta_info *sta = container_of(pubsta, struct sta_info, sta); | |
419 | u16 tid; | |
420 | ||
421 | if (unlikely(!ieee80211_is_data_qos(hdr->frame_control))) | |
422 | return; | |
423 | ||
424 | if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE))) | |
425 | return; | |
426 | ||
427 | tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; | |
a622ab72 | 428 | if (likely(sta->ampdu_mlme.tid_tx[tid])) |
ec8aa669 FF |
429 | return; |
430 | ||
48124d1a LR |
431 | if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO) |
432 | return; | |
433 | ||
bd2ce6e4 | 434 | ieee80211_start_tx_ba_session(pubsta, tid, 5000); |
ec8aa669 FF |
435 | } |
436 | ||
437 | static void | |
438 | minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, | |
439 | struct ieee80211_sta *sta, void *priv_sta, | |
440 | struct sk_buff *skb) | |
441 | { | |
442 | struct minstrel_ht_sta_priv *msp = priv_sta; | |
443 | struct minstrel_ht_sta *mi = &msp->ht; | |
444 | struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); | |
445 | struct ieee80211_tx_rate *ar = info->status.rates; | |
446 | struct minstrel_rate_stats *rate, *rate2; | |
447 | struct minstrel_priv *mp = priv; | |
a544ab7f | 448 | bool last; |
a544ab7f | 449 | int i; |
ec8aa669 FF |
450 | |
451 | if (!msp->is_ht) | |
452 | return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb); | |
453 | ||
454 | /* This packet was aggregated but doesn't carry status info */ | |
455 | if ((info->flags & IEEE80211_TX_CTL_AMPDU) && | |
456 | !(info->flags & IEEE80211_TX_STAT_AMPDU)) | |
457 | return; | |
458 | ||
15d46f38 BS |
459 | if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) { |
460 | info->status.ampdu_ack_len = | |
461 | (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0); | |
ec8aa669 FF |
462 | info->status.ampdu_len = 1; |
463 | } | |
464 | ||
465 | mi->ampdu_packets++; | |
466 | mi->ampdu_len += info->status.ampdu_len; | |
467 | ||
468 | if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) { | |
c7317e41 FF |
469 | mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len); |
470 | mi->sample_tries = 2; | |
ec8aa669 FF |
471 | mi->sample_count--; |
472 | } | |
473 | ||
8d5eab5a | 474 | if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) |
ec8aa669 | 475 | mi->sample_packets += info->status.ampdu_len; |
ec8aa669 | 476 | |
a0497f9f | 477 | last = !minstrel_ht_txstat_valid(mp, &ar[0]); |
ec8aa669 FF |
478 | for (i = 0; !last; i++) { |
479 | last = (i == IEEE80211_TX_MAX_RATES - 1) || | |
a0497f9f | 480 | !minstrel_ht_txstat_valid(mp, &ar[i + 1]); |
ec8aa669 | 481 | |
a0497f9f | 482 | rate = minstrel_ht_get_stats(mp, mi, &ar[i]); |
ec8aa669 | 483 | |
15d46f38 | 484 | if (last) |
ec8aa669 FF |
485 | rate->success += info->status.ampdu_ack_len; |
486 | ||
487 | rate->attempts += ar[i].count * info->status.ampdu_len; | |
488 | } | |
489 | ||
490 | /* | |
491 | * check for sudden death of spatial multiplexing, | |
492 | * downgrade to a lower number of streams if necessary. | |
493 | */ | |
494 | rate = minstrel_get_ratestats(mi, mi->max_tp_rate); | |
495 | if (rate->attempts > 30 && | |
496 | MINSTREL_FRAC(rate->success, rate->attempts) < | |
497 | MINSTREL_FRAC(20, 100)) | |
498 | minstrel_downgrade_rate(mi, &mi->max_tp_rate, true); | |
499 | ||
500 | rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2); | |
ecc3d5ae ML |
501 | if (rate2->attempts > 30 && |
502 | MINSTREL_FRAC(rate2->success, rate2->attempts) < | |
ec8aa669 FF |
503 | MINSTREL_FRAC(20, 100)) |
504 | minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false); | |
505 | ||
506 | if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) { | |
507 | minstrel_ht_update_stats(mp, mi); | |
a0497f9f FF |
508 | if (!(info->flags & IEEE80211_TX_CTL_AMPDU) && |
509 | mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) | |
6048d763 | 510 | minstrel_aggr_check(sta, skb); |
ec8aa669 FF |
511 | } |
512 | } | |
513 | ||
514 | static void | |
515 | minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, | |
516 | int index) | |
517 | { | |
518 | struct minstrel_rate_stats *mr; | |
519 | const struct mcs_group *group; | |
520 | unsigned int tx_time, tx_time_rtscts, tx_time_data; | |
521 | unsigned int cw = mp->cw_min; | |
8fddddff | 522 | unsigned int ctime = 0; |
ec8aa669 FF |
523 | unsigned int t_slot = 9; /* FIXME */ |
524 | unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len); | |
a0497f9f | 525 | unsigned int overhead = 0, overhead_rtscts = 0; |
ec8aa669 FF |
526 | |
527 | mr = minstrel_get_ratestats(mi, index); | |
528 | if (mr->probability < MINSTREL_FRAC(1, 10)) { | |
529 | mr->retry_count = 1; | |
530 | mr->retry_count_rtscts = 1; | |
531 | return; | |
532 | } | |
533 | ||
534 | mr->retry_count = 2; | |
535 | mr->retry_count_rtscts = 2; | |
536 | mr->retry_updated = true; | |
537 | ||
538 | group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; | |
539 | tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len; | |
8fddddff DH |
540 | |
541 | /* Contention time for first 2 tries */ | |
542 | ctime = (t_slot * cw) >> 1; | |
543 | cw = min((cw << 1) | 1, mp->cw_max); | |
544 | ctime += (t_slot * cw) >> 1; | |
545 | cw = min((cw << 1) | 1, mp->cw_max); | |
546 | ||
a0497f9f FF |
547 | if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) { |
548 | overhead = mi->overhead; | |
549 | overhead_rtscts = mi->overhead_rtscts; | |
550 | } | |
551 | ||
8fddddff | 552 | /* Total TX time for data and Contention after first 2 tries */ |
a0497f9f FF |
553 | tx_time = ctime + 2 * (overhead + tx_time_data); |
554 | tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data); | |
8fddddff DH |
555 | |
556 | /* See how many more tries we can fit inside segment size */ | |
ec8aa669 | 557 | do { |
8fddddff DH |
558 | /* Contention time for this try */ |
559 | ctime = (t_slot * cw) >> 1; | |
560 | cw = min((cw << 1) | 1, mp->cw_max); | |
561 | ||
562 | /* Total TX time after this try */ | |
a0497f9f FF |
563 | tx_time += ctime + overhead + tx_time_data; |
564 | tx_time_rtscts += ctime + overhead_rtscts + tx_time_data; | |
8fddddff | 565 | |
ec8aa669 FF |
566 | if (tx_time_rtscts < mp->segment_size) |
567 | mr->retry_count_rtscts++; | |
568 | } while ((tx_time < mp->segment_size) && | |
569 | (++mr->retry_count < mp->max_retry)); | |
570 | } | |
571 | ||
572 | ||
573 | static void | |
574 | minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, | |
575 | struct ieee80211_tx_rate *rate, int index, | |
ec8aa669 FF |
576 | bool sample, bool rtscts) |
577 | { | |
578 | const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; | |
579 | struct minstrel_rate_stats *mr; | |
580 | ||
581 | mr = minstrel_get_ratestats(mi, index); | |
582 | if (!mr->retry_updated) | |
583 | minstrel_calc_retransmit(mp, mi, index); | |
584 | ||
c7317e41 FF |
585 | if (sample) |
586 | rate->count = 1; | |
587 | else if (mr->probability < MINSTREL_FRAC(20, 100)) | |
ec8aa669 FF |
588 | rate->count = 2; |
589 | else if (rtscts) | |
590 | rate->count = mr->retry_count_rtscts; | |
591 | else | |
592 | rate->count = mr->retry_count; | |
593 | ||
a0497f9f | 594 | rate->flags = 0; |
9d468d22 | 595 | if (rtscts) |
ec8aa669 | 596 | rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS; |
a0497f9f FF |
597 | |
598 | if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) { | |
599 | rate->idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)]; | |
600 | return; | |
601 | } | |
602 | ||
603 | rate->flags |= IEEE80211_TX_RC_MCS | group->flags; | |
ec8aa669 FF |
604 | rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES; |
605 | } | |
606 | ||
607 | static inline int | |
608 | minstrel_get_duration(int index) | |
609 | { | |
610 | const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; | |
611 | return group->duration[index % MCS_GROUP_RATES]; | |
612 | } | |
613 | ||
614 | static int | |
615 | minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) | |
616 | { | |
617 | struct minstrel_rate_stats *mr; | |
618 | struct minstrel_mcs_group_data *mg; | |
619 | int sample_idx = 0; | |
620 | ||
621 | if (mi->sample_wait > 0) { | |
622 | mi->sample_wait--; | |
623 | return -1; | |
624 | } | |
625 | ||
626 | if (!mi->sample_tries) | |
627 | return -1; | |
628 | ||
629 | mi->sample_tries--; | |
630 | mg = &mi->groups[mi->sample_group]; | |
631 | sample_idx = sample_table[mg->column][mg->index]; | |
632 | mr = &mg->rates[sample_idx]; | |
633 | sample_idx += mi->sample_group * MCS_GROUP_RATES; | |
8d5eab5a | 634 | minstrel_next_sample_idx(mi); |
ec8aa669 | 635 | |
ba6fa29c HS |
636 | /* |
637 | * Sampling might add some overhead (RTS, no aggregation) | |
638 | * to the frame. Hence, don't use sampling for the currently | |
639 | * used max TP rate. | |
640 | */ | |
641 | if (sample_idx == mi->max_tp_rate) | |
642 | return -1; | |
ec8aa669 FF |
643 | /* |
644 | * When not using MRR, do not sample if the probability is already | |
645 | * higher than 95% to avoid wasting airtime | |
646 | */ | |
647 | if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100))) | |
8d5eab5a | 648 | return -1; |
ec8aa669 FF |
649 | |
650 | /* | |
651 | * Make sure that lower rates get sampled only occasionally, | |
652 | * if the link is working perfectly. | |
653 | */ | |
654 | if (minstrel_get_duration(sample_idx) > | |
655 | minstrel_get_duration(mi->max_tp_rate)) { | |
c7317e41 | 656 | if (mr->sample_skipped < 20) |
8d5eab5a | 657 | return -1; |
ec8aa669 FF |
658 | |
659 | if (mi->sample_slow++ > 2) | |
8d5eab5a | 660 | return -1; |
ec8aa669 FF |
661 | } |
662 | ||
663 | return sample_idx; | |
ec8aa669 FF |
664 | } |
665 | ||
a0497f9f FF |
666 | static void |
667 | minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp, | |
668 | struct minstrel_ht_sta *mi, bool val) | |
669 | { | |
670 | u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported; | |
671 | ||
672 | if (!supported || !mi->cck_supported_short) | |
673 | return; | |
674 | ||
675 | if (supported & (mi->cck_supported_short << (val * 4))) | |
676 | return; | |
677 | ||
678 | supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4); | |
679 | mi->groups[MINSTREL_CCK_GROUP].supported = supported; | |
680 | } | |
681 | ||
ec8aa669 FF |
682 | static void |
683 | minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, | |
684 | struct ieee80211_tx_rate_control *txrc) | |
685 | { | |
686 | struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); | |
687 | struct ieee80211_tx_rate *ar = info->status.rates; | |
688 | struct minstrel_ht_sta_priv *msp = priv_sta; | |
689 | struct minstrel_ht_sta *mi = &msp->ht; | |
690 | struct minstrel_priv *mp = priv; | |
691 | int sample_idx; | |
c7317e41 | 692 | bool sample = false; |
ec8aa669 FF |
693 | |
694 | if (rate_control_send_low(sta, priv_sta, txrc)) | |
695 | return; | |
696 | ||
697 | if (!msp->is_ht) | |
698 | return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc); | |
699 | ||
700 | info->flags |= mi->tx_flags; | |
a0497f9f | 701 | minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble); |
6de062ce HS |
702 | |
703 | /* Don't use EAPOL frames for sampling on non-mrr hw */ | |
704 | if (mp->hw->max_rates == 1 && | |
705 | txrc->skb->protocol == cpu_to_be16(ETH_P_PAE)) | |
706 | sample_idx = -1; | |
707 | else | |
708 | sample_idx = minstrel_get_sample_rate(mp, mi); | |
24f7580e ZK |
709 | |
710 | #ifdef CONFIG_MAC80211_DEBUGFS | |
711 | /* use fixed index if set */ | |
2a9e6c58 SRR |
712 | if (mp->fixed_rate_idx != -1) { |
713 | mi->max_tp_rate = mp->fixed_rate_idx; | |
714 | mi->max_tp_rate2 = mp->fixed_rate_idx; | |
715 | mi->max_prob_rate = mp->fixed_rate_idx; | |
716 | sample_idx = -1; | |
717 | } | |
24f7580e ZK |
718 | #endif |
719 | ||
ec8aa669 | 720 | if (sample_idx >= 0) { |
c7317e41 | 721 | sample = true; |
ec8aa669 | 722 | minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx, |
6048d763 | 723 | true, false); |
ec8aa669 FF |
724 | info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; |
725 | } else { | |
726 | minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate, | |
6048d763 | 727 | false, false); |
ec8aa669 | 728 | } |
ec8aa669 | 729 | |
cf28d793 HS |
730 | if (mp->hw->max_rates >= 3) { |
731 | /* | |
732 | * At least 3 tx rates supported, use | |
733 | * sample_rate -> max_tp_rate -> max_prob_rate for sampling and | |
734 | * max_tp_rate -> max_tp_rate2 -> max_prob_rate by default. | |
735 | */ | |
736 | if (sample_idx >= 0) | |
737 | minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate, | |
6048d763 | 738 | false, false); |
cf28d793 HS |
739 | else |
740 | minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2, | |
6048d763 | 741 | false, true); |
cf28d793 HS |
742 | |
743 | minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, | |
6048d763 | 744 | false, !sample); |
cf28d793 HS |
745 | |
746 | ar[3].count = 0; | |
747 | ar[3].idx = -1; | |
748 | } else if (mp->hw->max_rates == 2) { | |
749 | /* | |
750 | * Only 2 tx rates supported, use | |
751 | * sample_rate -> max_prob_rate for sampling and | |
752 | * max_tp_rate -> max_prob_rate by default. | |
753 | */ | |
754 | minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_prob_rate, | |
6048d763 | 755 | false, !sample); |
cf28d793 HS |
756 | |
757 | ar[2].count = 0; | |
758 | ar[2].idx = -1; | |
759 | } else { | |
760 | /* Not using MRR, only use the first rate */ | |
761 | ar[1].count = 0; | |
762 | ar[1].idx = -1; | |
763 | } | |
ec8aa669 FF |
764 | |
765 | mi->total_packets++; | |
766 | ||
767 | /* wraparound */ | |
768 | if (mi->total_packets == ~0) { | |
769 | mi->total_packets = 0; | |
770 | mi->sample_packets = 0; | |
771 | } | |
772 | } | |
773 | ||
a0497f9f FF |
774 | static void |
775 | minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, | |
776 | struct ieee80211_supported_band *sband, | |
777 | struct ieee80211_sta *sta) | |
778 | { | |
779 | int i; | |
780 | ||
781 | if (sband->band != IEEE80211_BAND_2GHZ) | |
782 | return; | |
783 | ||
784 | mi->cck_supported = 0; | |
785 | mi->cck_supported_short = 0; | |
786 | for (i = 0; i < 4; i++) { | |
787 | if (!rate_supported(sta, sband->band, mp->cck_rates[i])) | |
788 | continue; | |
789 | ||
790 | mi->cck_supported |= BIT(i); | |
791 | if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE) | |
792 | mi->cck_supported_short |= BIT(i); | |
793 | } | |
794 | ||
795 | mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported; | |
796 | } | |
797 | ||
ec8aa669 FF |
798 | static void |
799 | minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, | |
64f68e5d | 800 | struct ieee80211_sta *sta, void *priv_sta) |
ec8aa669 FF |
801 | { |
802 | struct minstrel_priv *mp = priv; | |
803 | struct minstrel_ht_sta_priv *msp = priv_sta; | |
804 | struct minstrel_ht_sta *mi = &msp->ht; | |
805 | struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs; | |
ec8aa669 | 806 | u16 sta_cap = sta->ht_cap.cap; |
4dc217df | 807 | int n_supported = 0; |
ec8aa669 FF |
808 | int ack_dur; |
809 | int stbc; | |
810 | int i; | |
e9219779 | 811 | unsigned int smps; |
ec8aa669 FF |
812 | |
813 | /* fall back to the old minstrel for legacy stations */ | |
4dc217df FF |
814 | if (!sta->ht_cap.ht_supported) |
815 | goto use_legacy; | |
ec8aa669 FF |
816 | |
817 | BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != | |
a0497f9f | 818 | MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1); |
ec8aa669 FF |
819 | |
820 | msp->is_ht = true; | |
821 | memset(mi, 0, sizeof(*mi)); | |
822 | mi->stats_update = jiffies; | |
823 | ||
4ee73f33 MK |
824 | ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1); |
825 | mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1) + ack_dur; | |
ec8aa669 FF |
826 | mi->overhead_rtscts = mi->overhead + 2 * ack_dur; |
827 | ||
828 | mi->avg_ampdu_len = MINSTREL_FRAC(1, 1); | |
829 | ||
830 | /* When using MRR, sample more on the first attempt, without delay */ | |
831 | if (mp->has_mrr) { | |
832 | mi->sample_count = 16; | |
833 | mi->sample_wait = 0; | |
834 | } else { | |
835 | mi->sample_count = 8; | |
836 | mi->sample_wait = 8; | |
837 | } | |
838 | mi->sample_tries = 4; | |
839 | ||
840 | stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >> | |
841 | IEEE80211_HT_CAP_RX_STBC_SHIFT; | |
842 | mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT; | |
843 | ||
844 | if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING) | |
845 | mi->tx_flags |= IEEE80211_TX_CTL_LDPC; | |
846 | ||
e9219779 HS |
847 | smps = (sta_cap & IEEE80211_HT_CAP_SM_PS) >> |
848 | IEEE80211_HT_CAP_SM_PS_SHIFT; | |
849 | ||
ec8aa669 | 850 | for (i = 0; i < ARRAY_SIZE(mi->groups); i++) { |
ec8aa669 | 851 | mi->groups[i].supported = 0; |
a0497f9f FF |
852 | if (i == MINSTREL_CCK_GROUP) { |
853 | minstrel_ht_update_cck(mp, mi, sband, sta); | |
854 | continue; | |
855 | } | |
856 | ||
ec8aa669 | 857 | if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) { |
e1a0c6b3 JB |
858 | if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) { |
859 | if (!(sta_cap & IEEE80211_HT_CAP_SGI_40)) | |
860 | continue; | |
861 | } else { | |
862 | if (!(sta_cap & IEEE80211_HT_CAP_SGI_20)) | |
863 | continue; | |
864 | } | |
ec8aa669 FF |
865 | } |
866 | ||
e1a0c6b3 JB |
867 | if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH && |
868 | sta->bandwidth < IEEE80211_STA_RX_BW_40) | |
ec8aa669 FF |
869 | continue; |
870 | ||
e9219779 HS |
871 | /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */ |
872 | if (smps == WLAN_HT_CAP_SM_PS_STATIC && | |
873 | minstrel_mcs_groups[i].streams > 1) | |
874 | continue; | |
875 | ||
ec8aa669 FF |
876 | mi->groups[i].supported = |
877 | mcs->rx_mask[minstrel_mcs_groups[i].streams - 1]; | |
4dc217df FF |
878 | |
879 | if (mi->groups[i].supported) | |
880 | n_supported++; | |
ec8aa669 | 881 | } |
4dc217df FF |
882 | |
883 | if (!n_supported) | |
884 | goto use_legacy; | |
885 | ||
886 | return; | |
887 | ||
888 | use_legacy: | |
889 | msp->is_ht = false; | |
890 | memset(&msp->legacy, 0, sizeof(msp->legacy)); | |
891 | msp->legacy.r = msp->ratelist; | |
892 | msp->legacy.sample_table = msp->sample_table; | |
893 | return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy); | |
ec8aa669 FF |
894 | } |
895 | ||
896 | static void | |
897 | minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband, | |
898 | struct ieee80211_sta *sta, void *priv_sta) | |
899 | { | |
64f68e5d | 900 | minstrel_ht_update_caps(priv, sband, sta, priv_sta); |
ec8aa669 FF |
901 | } |
902 | ||
903 | static void | |
904 | minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband, | |
905 | struct ieee80211_sta *sta, void *priv_sta, | |
64f68e5d | 906 | u32 changed) |
ec8aa669 | 907 | { |
64f68e5d | 908 | minstrel_ht_update_caps(priv, sband, sta, priv_sta); |
ec8aa669 FF |
909 | } |
910 | ||
911 | static void * | |
912 | minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp) | |
913 | { | |
914 | struct ieee80211_supported_band *sband; | |
915 | struct minstrel_ht_sta_priv *msp; | |
916 | struct minstrel_priv *mp = priv; | |
917 | struct ieee80211_hw *hw = mp->hw; | |
918 | int max_rates = 0; | |
919 | int i; | |
920 | ||
921 | for (i = 0; i < IEEE80211_NUM_BANDS; i++) { | |
922 | sband = hw->wiphy->bands[i]; | |
923 | if (sband && sband->n_bitrates > max_rates) | |
924 | max_rates = sband->n_bitrates; | |
925 | } | |
926 | ||
472dd35c | 927 | msp = kzalloc(sizeof(*msp), gfp); |
ec8aa669 FF |
928 | if (!msp) |
929 | return NULL; | |
930 | ||
931 | msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp); | |
932 | if (!msp->ratelist) | |
933 | goto error; | |
934 | ||
935 | msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp); | |
936 | if (!msp->sample_table) | |
937 | goto error1; | |
938 | ||
939 | return msp; | |
940 | ||
941 | error1: | |
7e988014 | 942 | kfree(msp->ratelist); |
ec8aa669 FF |
943 | error: |
944 | kfree(msp); | |
945 | return NULL; | |
946 | } | |
947 | ||
948 | static void | |
949 | minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta) | |
950 | { | |
951 | struct minstrel_ht_sta_priv *msp = priv_sta; | |
952 | ||
953 | kfree(msp->sample_table); | |
954 | kfree(msp->ratelist); | |
955 | kfree(msp); | |
956 | } | |
957 | ||
958 | static void * | |
959 | minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) | |
960 | { | |
961 | return mac80211_minstrel.alloc(hw, debugfsdir); | |
962 | } | |
963 | ||
964 | static void | |
965 | minstrel_ht_free(void *priv) | |
966 | { | |
967 | mac80211_minstrel.free(priv); | |
968 | } | |
969 | ||
970 | static struct rate_control_ops mac80211_minstrel_ht = { | |
971 | .name = "minstrel_ht", | |
972 | .tx_status = minstrel_ht_tx_status, | |
973 | .get_rate = minstrel_ht_get_rate, | |
974 | .rate_init = minstrel_ht_rate_init, | |
975 | .rate_update = minstrel_ht_rate_update, | |
976 | .alloc_sta = minstrel_ht_alloc_sta, | |
977 | .free_sta = minstrel_ht_free_sta, | |
978 | .alloc = minstrel_ht_alloc, | |
979 | .free = minstrel_ht_free, | |
980 | #ifdef CONFIG_MAC80211_DEBUGFS | |
981 | .add_sta_debugfs = minstrel_ht_add_sta_debugfs, | |
982 | .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs, | |
983 | #endif | |
984 | }; | |
985 | ||
986 | ||
987 | static void | |
988 | init_sample_table(void) | |
989 | { | |
990 | int col, i, new_idx; | |
991 | u8 rnd[MCS_GROUP_RATES]; | |
992 | ||
993 | memset(sample_table, 0xff, sizeof(sample_table)); | |
994 | for (col = 0; col < SAMPLE_COLUMNS; col++) { | |
995 | for (i = 0; i < MCS_GROUP_RATES; i++) { | |
996 | get_random_bytes(rnd, sizeof(rnd)); | |
997 | new_idx = (i + rnd[i]) % MCS_GROUP_RATES; | |
998 | ||
999 | while (sample_table[col][new_idx] != 0xff) | |
1000 | new_idx = (new_idx + 1) % MCS_GROUP_RATES; | |
1001 | ||
1002 | sample_table[col][new_idx] = i; | |
1003 | } | |
1004 | } | |
1005 | } | |
1006 | ||
1007 | int __init | |
1008 | rc80211_minstrel_ht_init(void) | |
1009 | { | |
1010 | init_sample_table(); | |
1011 | return ieee80211_rate_control_register(&mac80211_minstrel_ht); | |
1012 | } | |
1013 | ||
1014 | void | |
1015 | rc80211_minstrel_ht_exit(void) | |
1016 | { | |
1017 | ieee80211_rate_control_unregister(&mac80211_minstrel_ht); | |
1018 | } |