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netfilter: nft_payload: work around vlan header stripping
[deliverable/linux.git] / net / mac80211 / rc80211_minstrel.c
1 /*
2 * Copyright (C) 2008 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 * Based on minstrel.c:
9 * Copyright (C) 2005-2007 Derek Smithies <derek@indranet.co.nz>
10 * Sponsored by Indranet Technologies Ltd
11 *
12 * Based on sample.c:
13 * Copyright (c) 2005 John Bicket
14 * All rights reserved.
15 *
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
18 * are met:
19 * 1. Redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer,
21 * without modification.
22 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
23 * similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
24 * redistribution must be conditioned upon including a substantially
25 * similar Disclaimer requirement for further binary redistribution.
26 * 3. Neither the names of the above-listed copyright holders nor the names
27 * of any contributors may be used to endorse or promote products derived
28 * from this software without specific prior written permission.
29 *
30 * Alternatively, this software may be distributed under the terms of the
31 * GNU General Public License ("GPL") version 2 as published by the Free
32 * Software Foundation.
33 *
34 * NO WARRANTY
35 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
36 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
37 * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
38 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
39 * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
40 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
41 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
42 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
43 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
44 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
45 * THE POSSIBILITY OF SUCH DAMAGES.
46 */
47 #include <linux/netdevice.h>
48 #include <linux/types.h>
49 #include <linux/skbuff.h>
50 #include <linux/debugfs.h>
51 #include <linux/random.h>
52 #include <linux/ieee80211.h>
53 #include <linux/slab.h>
54 #include <net/mac80211.h>
55 #include "rate.h"
56 #include "rc80211_minstrel.h"
57
58 #define SAMPLE_TBL(_mi, _idx, _col) \
59 _mi->sample_table[(_idx * SAMPLE_COLUMNS) + _col]
60
61 /* convert mac80211 rate index to local array index */
62 static inline int
63 rix_to_ndx(struct minstrel_sta_info *mi, int rix)
64 {
65 int i = rix;
66 for (i = rix; i >= 0; i--)
67 if (mi->r[i].rix == rix)
68 break;
69 return i;
70 }
71
72 /* return current EMWA throughput */
73 int minstrel_get_tp_avg(struct minstrel_rate *mr, int prob_ewma)
74 {
75 int usecs;
76
77 usecs = mr->perfect_tx_time;
78 if (!usecs)
79 usecs = 1000000;
80
81 /* reset thr. below 10% success */
82 if (mr->stats.prob_ewma < MINSTREL_FRAC(10, 100))
83 return 0;
84
85 if (prob_ewma > MINSTREL_FRAC(90, 100))
86 return MINSTREL_TRUNC(100000 * (MINSTREL_FRAC(90, 100) / usecs));
87 else
88 return MINSTREL_TRUNC(100000 * (prob_ewma / usecs));
89 }
90
91 /* find & sort topmost throughput rates */
92 static inline void
93 minstrel_sort_best_tp_rates(struct minstrel_sta_info *mi, int i, u8 *tp_list)
94 {
95 int j = MAX_THR_RATES;
96 struct minstrel_rate_stats *tmp_mrs = &mi->r[j - 1].stats;
97 struct minstrel_rate_stats *cur_mrs = &mi->r[i].stats;
98
99 while (j > 0 && (minstrel_get_tp_avg(&mi->r[i], cur_mrs->prob_ewma) >
100 minstrel_get_tp_avg(&mi->r[tp_list[j - 1]], tmp_mrs->prob_ewma))) {
101 j--;
102 tmp_mrs = &mi->r[tp_list[j - 1]].stats;
103 }
104
105 if (j < MAX_THR_RATES - 1)
106 memmove(&tp_list[j + 1], &tp_list[j], MAX_THR_RATES - (j + 1));
107 if (j < MAX_THR_RATES)
108 tp_list[j] = i;
109 }
110
111 static void
112 minstrel_set_rate(struct minstrel_sta_info *mi, struct ieee80211_sta_rates *ratetbl,
113 int offset, int idx)
114 {
115 struct minstrel_rate *r = &mi->r[idx];
116
117 ratetbl->rate[offset].idx = r->rix;
118 ratetbl->rate[offset].count = r->adjusted_retry_count;
119 ratetbl->rate[offset].count_cts = r->retry_count_cts;
120 ratetbl->rate[offset].count_rts = r->stats.retry_count_rtscts;
121 }
122
123 static void
124 minstrel_update_rates(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
125 {
126 struct ieee80211_sta_rates *ratetbl;
127 int i = 0;
128
129 ratetbl = kzalloc(sizeof(*ratetbl), GFP_ATOMIC);
130 if (!ratetbl)
131 return;
132
133 /* Start with max_tp_rate */
134 minstrel_set_rate(mi, ratetbl, i++, mi->max_tp_rate[0]);
135
136 if (mp->hw->max_rates >= 3) {
137 /* At least 3 tx rates supported, use max_tp_rate2 next */
138 minstrel_set_rate(mi, ratetbl, i++, mi->max_tp_rate[1]);
139 }
140
141 if (mp->hw->max_rates >= 2) {
142 /* At least 2 tx rates supported, use max_prob_rate next */
143 minstrel_set_rate(mi, ratetbl, i++, mi->max_prob_rate);
144 }
145
146 /* Use lowest rate last */
147 ratetbl->rate[i].idx = mi->lowest_rix;
148 ratetbl->rate[i].count = mp->max_retry;
149 ratetbl->rate[i].count_cts = mp->max_retry;
150 ratetbl->rate[i].count_rts = mp->max_retry;
151
152 rate_control_set_rates(mp->hw, mi->sta, ratetbl);
153 }
154
155 /*
156 * Recalculate statistics and counters of a given rate
157 */
158 void
159 minstrel_calc_rate_stats(struct minstrel_rate_stats *mrs)
160 {
161 if (unlikely(mrs->attempts > 0)) {
162 mrs->sample_skipped = 0;
163 mrs->cur_prob = MINSTREL_FRAC(mrs->success, mrs->attempts);
164 if (unlikely(!mrs->att_hist)) {
165 mrs->prob_ewma = mrs->cur_prob;
166 } else {
167 /* update exponential weighted moving variance */
168 mrs->prob_ewmsd = minstrel_ewmsd(mrs->prob_ewmsd,
169 mrs->cur_prob,
170 mrs->prob_ewma,
171 EWMA_LEVEL);
172
173 /*update exponential weighted moving avarage */
174 mrs->prob_ewma = minstrel_ewma(mrs->prob_ewma,
175 mrs->cur_prob,
176 EWMA_LEVEL);
177 }
178 mrs->att_hist += mrs->attempts;
179 mrs->succ_hist += mrs->success;
180 } else {
181 mrs->sample_skipped++;
182 }
183
184 mrs->last_success = mrs->success;
185 mrs->last_attempts = mrs->attempts;
186 mrs->success = 0;
187 mrs->attempts = 0;
188 }
189
190 static void
191 minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
192 {
193 u8 tmp_tp_rate[MAX_THR_RATES];
194 u8 tmp_prob_rate = 0;
195 int i, tmp_cur_tp, tmp_prob_tp;
196
197 for (i = 0; i < MAX_THR_RATES; i++)
198 tmp_tp_rate[i] = 0;
199
200 for (i = 0; i < mi->n_rates; i++) {
201 struct minstrel_rate *mr = &mi->r[i];
202 struct minstrel_rate_stats *mrs = &mi->r[i].stats;
203 struct minstrel_rate_stats *tmp_mrs = &mi->r[tmp_prob_rate].stats;
204
205 /* Update statistics of success probability per rate */
206 minstrel_calc_rate_stats(mrs);
207
208 /* Sample less often below the 10% chance of success.
209 * Sample less often above the 95% chance of success. */
210 if (mrs->prob_ewma > MINSTREL_FRAC(95, 100) ||
211 mrs->prob_ewma < MINSTREL_FRAC(10, 100)) {
212 mr->adjusted_retry_count = mrs->retry_count >> 1;
213 if (mr->adjusted_retry_count > 2)
214 mr->adjusted_retry_count = 2;
215 mr->sample_limit = 4;
216 } else {
217 mr->sample_limit = -1;
218 mr->adjusted_retry_count = mrs->retry_count;
219 }
220 if (!mr->adjusted_retry_count)
221 mr->adjusted_retry_count = 2;
222
223 minstrel_sort_best_tp_rates(mi, i, tmp_tp_rate);
224
225 /* To determine the most robust rate (max_prob_rate) used at
226 * 3rd mmr stage we distinct between two cases:
227 * (1) if any success probabilitiy >= 95%, out of those rates
228 * choose the maximum throughput rate as max_prob_rate
229 * (2) if all success probabilities < 95%, the rate with
230 * highest success probability is chosen as max_prob_rate */
231 if (mrs->prob_ewma >= MINSTREL_FRAC(95, 100)) {
232 tmp_cur_tp = minstrel_get_tp_avg(mr, mrs->prob_ewma);
233 tmp_prob_tp = minstrel_get_tp_avg(&mi->r[tmp_prob_rate],
234 tmp_mrs->prob_ewma);
235 if (tmp_cur_tp >= tmp_prob_tp)
236 tmp_prob_rate = i;
237 } else {
238 if (mrs->prob_ewma >= tmp_mrs->prob_ewma)
239 tmp_prob_rate = i;
240 }
241 }
242
243 /* Assign the new rate set */
244 memcpy(mi->max_tp_rate, tmp_tp_rate, sizeof(mi->max_tp_rate));
245 mi->max_prob_rate = tmp_prob_rate;
246
247 #ifdef CONFIG_MAC80211_DEBUGFS
248 /* use fixed index if set */
249 if (mp->fixed_rate_idx != -1) {
250 mi->max_tp_rate[0] = mp->fixed_rate_idx;
251 mi->max_tp_rate[1] = mp->fixed_rate_idx;
252 mi->max_prob_rate = mp->fixed_rate_idx;
253 }
254 #endif
255
256 /* Reset update timer */
257 mi->last_stats_update = jiffies;
258
259 minstrel_update_rates(mp, mi);
260 }
261
262 static void
263 minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband,
264 struct ieee80211_sta *sta, void *priv_sta,
265 struct ieee80211_tx_info *info)
266 {
267 struct minstrel_priv *mp = priv;
268 struct minstrel_sta_info *mi = priv_sta;
269 struct ieee80211_tx_rate *ar = info->status.rates;
270 int i, ndx;
271 int success;
272
273 success = !!(info->flags & IEEE80211_TX_STAT_ACK);
274
275 for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
276 if (ar[i].idx < 0)
277 break;
278
279 ndx = rix_to_ndx(mi, ar[i].idx);
280 if (ndx < 0)
281 continue;
282
283 mi->r[ndx].stats.attempts += ar[i].count;
284
285 if ((i != IEEE80211_TX_MAX_RATES - 1) && (ar[i + 1].idx < 0))
286 mi->r[ndx].stats.success += success;
287 }
288
289 if ((info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) && (i >= 0))
290 mi->sample_packets++;
291
292 if (mi->sample_deferred > 0)
293 mi->sample_deferred--;
294
295 if (time_after(jiffies, mi->last_stats_update +
296 (mp->update_interval * HZ) / 1000))
297 minstrel_update_stats(mp, mi);
298 }
299
300
301 static inline unsigned int
302 minstrel_get_retry_count(struct minstrel_rate *mr,
303 struct ieee80211_tx_info *info)
304 {
305 u8 retry = mr->adjusted_retry_count;
306
307 if (info->control.use_rts)
308 retry = max_t(u8, 2, min(mr->stats.retry_count_rtscts, retry));
309 else if (info->control.use_cts_prot)
310 retry = max_t(u8, 2, min(mr->retry_count_cts, retry));
311 return retry;
312 }
313
314
315 static int
316 minstrel_get_next_sample(struct minstrel_sta_info *mi)
317 {
318 unsigned int sample_ndx;
319 sample_ndx = SAMPLE_TBL(mi, mi->sample_row, mi->sample_column);
320 mi->sample_row++;
321 if ((int) mi->sample_row >= mi->n_rates) {
322 mi->sample_row = 0;
323 mi->sample_column++;
324 if (mi->sample_column >= SAMPLE_COLUMNS)
325 mi->sample_column = 0;
326 }
327 return sample_ndx;
328 }
329
330 static void
331 minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
332 void *priv_sta, struct ieee80211_tx_rate_control *txrc)
333 {
334 struct sk_buff *skb = txrc->skb;
335 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
336 struct minstrel_sta_info *mi = priv_sta;
337 struct minstrel_priv *mp = priv;
338 struct ieee80211_tx_rate *rate = &info->control.rates[0];
339 struct minstrel_rate *msr, *mr;
340 unsigned int ndx;
341 bool mrr_capable;
342 bool prev_sample;
343 int delta;
344 int sampling_ratio;
345
346 /* management/no-ack frames do not use rate control */
347 if (rate_control_send_low(sta, priv_sta, txrc))
348 return;
349
350 /* check multi-rate-retry capabilities & adjust lookaround_rate */
351 mrr_capable = mp->has_mrr &&
352 !txrc->rts &&
353 !txrc->bss_conf->use_cts_prot;
354 if (mrr_capable)
355 sampling_ratio = mp->lookaround_rate_mrr;
356 else
357 sampling_ratio = mp->lookaround_rate;
358
359 /* increase sum packet counter */
360 mi->total_packets++;
361
362 #ifdef CONFIG_MAC80211_DEBUGFS
363 if (mp->fixed_rate_idx != -1)
364 return;
365 #endif
366
367 delta = (mi->total_packets * sampling_ratio / 100) -
368 (mi->sample_packets + mi->sample_deferred / 2);
369
370 /* delta < 0: no sampling required */
371 prev_sample = mi->prev_sample;
372 mi->prev_sample = false;
373 if (delta < 0 || (!mrr_capable && prev_sample))
374 return;
375
376 if (mi->total_packets >= 10000) {
377 mi->sample_deferred = 0;
378 mi->sample_packets = 0;
379 mi->total_packets = 0;
380 } else if (delta > mi->n_rates * 2) {
381 /* With multi-rate retry, not every planned sample
382 * attempt actually gets used, due to the way the retry
383 * chain is set up - [max_tp,sample,prob,lowest] for
384 * sample_rate < max_tp.
385 *
386 * If there's too much sampling backlog and the link
387 * starts getting worse, minstrel would start bursting
388 * out lots of sampling frames, which would result
389 * in a large throughput loss. */
390 mi->sample_packets += (delta - mi->n_rates * 2);
391 }
392
393 /* get next random rate sample */
394 ndx = minstrel_get_next_sample(mi);
395 msr = &mi->r[ndx];
396 mr = &mi->r[mi->max_tp_rate[0]];
397
398 /* Decide if direct ( 1st mrr stage) or indirect (2nd mrr stage)
399 * rate sampling method should be used.
400 * Respect such rates that are not sampled for 20 interations.
401 */
402 if (mrr_capable &&
403 msr->perfect_tx_time > mr->perfect_tx_time &&
404 msr->stats.sample_skipped < 20) {
405 /* Only use IEEE80211_TX_CTL_RATE_CTRL_PROBE to mark
406 * packets that have the sampling rate deferred to the
407 * second MRR stage. Increase the sample counter only
408 * if the deferred sample rate was actually used.
409 * Use the sample_deferred counter to make sure that
410 * the sampling is not done in large bursts */
411 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
412 rate++;
413 mi->sample_deferred++;
414 } else {
415 if (!msr->sample_limit)
416 return;
417
418 mi->sample_packets++;
419 if (msr->sample_limit > 0)
420 msr->sample_limit--;
421 }
422
423 /* If we're not using MRR and the sampling rate already
424 * has a probability of >95%, we shouldn't be attempting
425 * to use it, as this only wastes precious airtime */
426 if (!mrr_capable &&
427 (mi->r[ndx].stats.prob_ewma > MINSTREL_FRAC(95, 100)))
428 return;
429
430 mi->prev_sample = true;
431
432 rate->idx = mi->r[ndx].rix;
433 rate->count = minstrel_get_retry_count(&mi->r[ndx], info);
434 }
435
436
437 static void
438 calc_rate_durations(enum ieee80211_band band,
439 struct minstrel_rate *d,
440 struct ieee80211_rate *rate,
441 struct cfg80211_chan_def *chandef)
442 {
443 int erp = !!(rate->flags & IEEE80211_RATE_ERP_G);
444 int shift = ieee80211_chandef_get_shift(chandef);
445
446 d->perfect_tx_time = ieee80211_frame_duration(band, 1200,
447 DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
448 shift);
449 d->ack_time = ieee80211_frame_duration(band, 10,
450 DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
451 shift);
452 }
453
454 static void
455 init_sample_table(struct minstrel_sta_info *mi)
456 {
457 unsigned int i, col, new_idx;
458 u8 rnd[8];
459
460 mi->sample_column = 0;
461 mi->sample_row = 0;
462 memset(mi->sample_table, 0xff, SAMPLE_COLUMNS * mi->n_rates);
463
464 for (col = 0; col < SAMPLE_COLUMNS; col++) {
465 prandom_bytes(rnd, sizeof(rnd));
466 for (i = 0; i < mi->n_rates; i++) {
467 new_idx = (i + rnd[i & 7]) % mi->n_rates;
468 while (SAMPLE_TBL(mi, new_idx, col) != 0xff)
469 new_idx = (new_idx + 1) % mi->n_rates;
470
471 SAMPLE_TBL(mi, new_idx, col) = i;
472 }
473 }
474 }
475
476 static void
477 minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
478 struct cfg80211_chan_def *chandef,
479 struct ieee80211_sta *sta, void *priv_sta)
480 {
481 struct minstrel_sta_info *mi = priv_sta;
482 struct minstrel_priv *mp = priv;
483 struct ieee80211_rate *ctl_rate;
484 unsigned int i, n = 0;
485 unsigned int t_slot = 9; /* FIXME: get real slot time */
486 u32 rate_flags;
487
488 mi->sta = sta;
489 mi->lowest_rix = rate_lowest_index(sband, sta);
490 ctl_rate = &sband->bitrates[mi->lowest_rix];
491 mi->sp_ack_dur = ieee80211_frame_duration(sband->band, 10,
492 ctl_rate->bitrate,
493 !!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1,
494 ieee80211_chandef_get_shift(chandef));
495
496 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
497 memset(mi->max_tp_rate, 0, sizeof(mi->max_tp_rate));
498 mi->max_prob_rate = 0;
499
500 for (i = 0; i < sband->n_bitrates; i++) {
501 struct minstrel_rate *mr = &mi->r[n];
502 struct minstrel_rate_stats *mrs = &mi->r[n].stats;
503 unsigned int tx_time = 0, tx_time_cts = 0, tx_time_rtscts = 0;
504 unsigned int tx_time_single;
505 unsigned int cw = mp->cw_min;
506 int shift;
507
508 if (!rate_supported(sta, sband->band, i))
509 continue;
510 if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
511 continue;
512
513 n++;
514 memset(mr, 0, sizeof(*mr));
515 memset(mrs, 0, sizeof(*mrs));
516
517 mr->rix = i;
518 shift = ieee80211_chandef_get_shift(chandef);
519 mr->bitrate = DIV_ROUND_UP(sband->bitrates[i].bitrate,
520 (1 << shift) * 5);
521 calc_rate_durations(sband->band, mr, &sband->bitrates[i],
522 chandef);
523
524 /* calculate maximum number of retransmissions before
525 * fallback (based on maximum segment size) */
526 mr->sample_limit = -1;
527 mrs->retry_count = 1;
528 mr->retry_count_cts = 1;
529 mrs->retry_count_rtscts = 1;
530 tx_time = mr->perfect_tx_time + mi->sp_ack_dur;
531 do {
532 /* add one retransmission */
533 tx_time_single = mr->ack_time + mr->perfect_tx_time;
534
535 /* contention window */
536 tx_time_single += (t_slot * cw) >> 1;
537 cw = min((cw << 1) | 1, mp->cw_max);
538
539 tx_time += tx_time_single;
540 tx_time_cts += tx_time_single + mi->sp_ack_dur;
541 tx_time_rtscts += tx_time_single + 2 * mi->sp_ack_dur;
542 if ((tx_time_cts < mp->segment_size) &&
543 (mr->retry_count_cts < mp->max_retry))
544 mr->retry_count_cts++;
545 if ((tx_time_rtscts < mp->segment_size) &&
546 (mrs->retry_count_rtscts < mp->max_retry))
547 mrs->retry_count_rtscts++;
548 } while ((tx_time < mp->segment_size) &&
549 (++mr->stats.retry_count < mp->max_retry));
550 mr->adjusted_retry_count = mrs->retry_count;
551 if (!(sband->bitrates[i].flags & IEEE80211_RATE_ERP_G))
552 mr->retry_count_cts = mrs->retry_count;
553 }
554
555 for (i = n; i < sband->n_bitrates; i++) {
556 struct minstrel_rate *mr = &mi->r[i];
557 mr->rix = -1;
558 }
559
560 mi->n_rates = n;
561 mi->last_stats_update = jiffies;
562
563 init_sample_table(mi);
564 minstrel_update_rates(mp, mi);
565 }
566
567 static void *
568 minstrel_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
569 {
570 struct ieee80211_supported_band *sband;
571 struct minstrel_sta_info *mi;
572 struct minstrel_priv *mp = priv;
573 struct ieee80211_hw *hw = mp->hw;
574 int max_rates = 0;
575 int i;
576
577 mi = kzalloc(sizeof(struct minstrel_sta_info), gfp);
578 if (!mi)
579 return NULL;
580
581 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
582 sband = hw->wiphy->bands[i];
583 if (sband && sband->n_bitrates > max_rates)
584 max_rates = sband->n_bitrates;
585 }
586
587 mi->r = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
588 if (!mi->r)
589 goto error;
590
591 mi->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
592 if (!mi->sample_table)
593 goto error1;
594
595 mi->last_stats_update = jiffies;
596 return mi;
597
598 error1:
599 kfree(mi->r);
600 error:
601 kfree(mi);
602 return NULL;
603 }
604
605 static void
606 minstrel_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
607 {
608 struct minstrel_sta_info *mi = priv_sta;
609
610 kfree(mi->sample_table);
611 kfree(mi->r);
612 kfree(mi);
613 }
614
615 static void
616 minstrel_init_cck_rates(struct minstrel_priv *mp)
617 {
618 static const int bitrates[4] = { 10, 20, 55, 110 };
619 struct ieee80211_supported_band *sband;
620 u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
621 int i, j;
622
623 sband = mp->hw->wiphy->bands[IEEE80211_BAND_2GHZ];
624 if (!sband)
625 return;
626
627 for (i = 0, j = 0; i < sband->n_bitrates; i++) {
628 struct ieee80211_rate *rate = &sband->bitrates[i];
629
630 if (rate->flags & IEEE80211_RATE_ERP_G)
631 continue;
632
633 if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
634 continue;
635
636 for (j = 0; j < ARRAY_SIZE(bitrates); j++) {
637 if (rate->bitrate != bitrates[j])
638 continue;
639
640 mp->cck_rates[j] = i;
641 break;
642 }
643 }
644 }
645
646 static void *
647 minstrel_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
648 {
649 struct minstrel_priv *mp;
650
651 mp = kzalloc(sizeof(struct minstrel_priv), GFP_ATOMIC);
652 if (!mp)
653 return NULL;
654
655 /* contention window settings
656 * Just an approximation. Using the per-queue values would complicate
657 * the calculations and is probably unnecessary */
658 mp->cw_min = 15;
659 mp->cw_max = 1023;
660
661 /* number of packets (in %) to use for sampling other rates
662 * sample less often for non-mrr packets, because the overhead
663 * is much higher than with mrr */
664 mp->lookaround_rate = 5;
665 mp->lookaround_rate_mrr = 10;
666
667 /* maximum time that the hw is allowed to stay in one MRR segment */
668 mp->segment_size = 6000;
669
670 if (hw->max_rate_tries > 0)
671 mp->max_retry = hw->max_rate_tries;
672 else
673 /* safe default, does not necessarily have to match hw properties */
674 mp->max_retry = 7;
675
676 if (hw->max_rates >= 4)
677 mp->has_mrr = true;
678
679 mp->hw = hw;
680 mp->update_interval = 100;
681
682 #ifdef CONFIG_MAC80211_DEBUGFS
683 mp->fixed_rate_idx = (u32) -1;
684 mp->dbg_fixed_rate = debugfs_create_u32("fixed_rate_idx",
685 S_IRUGO | S_IWUGO, debugfsdir, &mp->fixed_rate_idx);
686 #endif
687
688 minstrel_init_cck_rates(mp);
689
690 return mp;
691 }
692
693 static void
694 minstrel_free(void *priv)
695 {
696 #ifdef CONFIG_MAC80211_DEBUGFS
697 debugfs_remove(((struct minstrel_priv *)priv)->dbg_fixed_rate);
698 #endif
699 kfree(priv);
700 }
701
702 static u32 minstrel_get_expected_throughput(void *priv_sta)
703 {
704 struct minstrel_sta_info *mi = priv_sta;
705 struct minstrel_rate_stats *tmp_mrs;
706 int idx = mi->max_tp_rate[0];
707 int tmp_cur_tp;
708
709 /* convert pkt per sec in kbps (1200 is the average pkt size used for
710 * computing cur_tp
711 */
712 tmp_mrs = &mi->r[idx].stats;
713 tmp_cur_tp = minstrel_get_tp_avg(&mi->r[idx], tmp_mrs->prob_ewma);
714 tmp_cur_tp = tmp_cur_tp * 1200 * 8 / 1024;
715
716 return tmp_cur_tp;
717 }
718
719 const struct rate_control_ops mac80211_minstrel = {
720 .name = "minstrel",
721 .tx_status_noskb = minstrel_tx_status,
722 .get_rate = minstrel_get_rate,
723 .rate_init = minstrel_rate_init,
724 .alloc = minstrel_alloc,
725 .free = minstrel_free,
726 .alloc_sta = minstrel_alloc_sta,
727 .free_sta = minstrel_free_sta,
728 #ifdef CONFIG_MAC80211_DEBUGFS
729 .add_sta_debugfs = minstrel_add_sta_debugfs,
730 .remove_sta_debugfs = minstrel_remove_sta_debugfs,
731 #endif
732 .get_expected_throughput = minstrel_get_expected_throughput,
733 };
734
735 int __init
736 rc80211_minstrel_init(void)
737 {
738 return ieee80211_rate_control_register(&mac80211_minstrel);
739 }
740
741 void
742 rc80211_minstrel_exit(void)
743 {
744 ieee80211_rate_control_unregister(&mac80211_minstrel);
745 }
746
Linux kernel - Deliverables
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