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drm/tegra: fb: Add error codes to error messages
[linux-2.6/btrfs-unstable.git] / net / mac80211 / rc80211_minstrel.c
blob2baa7ed8789dce2752a3f69d5cc3627bbbd47c76
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 /* find & sort topmost throughput rates */
73 static inline void
74 minstrel_sort_best_tp_rates(struct minstrel_sta_info *mi, int i, u8 *tp_list)
75 {
76 int j = MAX_THR_RATES;
77
78 while (j > 0 && mi->r[i].stats.cur_tp > mi->r[tp_list[j - 1]].stats.cur_tp)
79 j--;
80 if (j < MAX_THR_RATES - 1)
81 memmove(&tp_list[j + 1], &tp_list[j], MAX_THR_RATES - (j + 1));
82 if (j < MAX_THR_RATES)
83 tp_list[j] = i;
84 }
85
86 static void
87 minstrel_set_rate(struct minstrel_sta_info *mi, struct ieee80211_sta_rates *ratetbl,
88 int offset, int idx)
89 {
90 struct minstrel_rate *r = &mi->r[idx];
91
92 ratetbl->rate[offset].idx = r->rix;
93 ratetbl->rate[offset].count = r->adjusted_retry_count;
94 ratetbl->rate[offset].count_cts = r->retry_count_cts;
95 ratetbl->rate[offset].count_rts = r->stats.retry_count_rtscts;
96 }
97
98 static void
99 minstrel_update_rates(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
100 {
101 struct ieee80211_sta_rates *ratetbl;
102 int i = 0;
103
104 ratetbl = kzalloc(sizeof(*ratetbl), GFP_ATOMIC);
105 if (!ratetbl)
106 return;
107
108 /* Start with max_tp_rate */
109 minstrel_set_rate(mi, ratetbl, i++, mi->max_tp_rate[0]);
110
111 if (mp->hw->max_rates >= 3) {
112 /* At least 3 tx rates supported, use max_tp_rate2 next */
113 minstrel_set_rate(mi, ratetbl, i++, mi->max_tp_rate[1]);
114 }
115
116 if (mp->hw->max_rates >= 2) {
117 /* At least 2 tx rates supported, use max_prob_rate next */
118 minstrel_set_rate(mi, ratetbl, i++, mi->max_prob_rate);
119 }
120
121 /* Use lowest rate last */
122 ratetbl->rate[i].idx = mi->lowest_rix;
123 ratetbl->rate[i].count = mp->max_retry;
124 ratetbl->rate[i].count_cts = mp->max_retry;
125 ratetbl->rate[i].count_rts = mp->max_retry;
126
127 rate_control_set_rates(mp->hw, mi->sta, ratetbl);
128 }
129
130 static void
131 minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
132 {
133 u8 tmp_tp_rate[MAX_THR_RATES];
134 u8 tmp_prob_rate = 0;
135 u32 usecs;
136 int i;
137
138 for (i = 0; i < MAX_THR_RATES; i++)
139 tmp_tp_rate[i] = 0;
140
141 for (i = 0; i < mi->n_rates; i++) {
142 struct minstrel_rate *mr = &mi->r[i];
143 struct minstrel_rate_stats *mrs = &mi->r[i].stats;
144
145 usecs = mr->perfect_tx_time;
146 if (!usecs)
147 usecs = 1000000;
148
149 if (unlikely(mrs->attempts > 0)) {
150 mrs->sample_skipped = 0;
151 mrs->cur_prob = MINSTREL_FRAC(mrs->success,
152 mrs->attempts);
153 mrs->succ_hist += mrs->success;
154 mrs->att_hist += mrs->attempts;
155 mrs->probability = minstrel_ewma(mrs->probability,
156 mrs->cur_prob,
157 EWMA_LEVEL);
158 } else
159 mrs->sample_skipped++;
160
161 mrs->last_success = mrs->success;
162 mrs->last_attempts = mrs->attempts;
163 mrs->success = 0;
164 mrs->attempts = 0;
165
166 /* Update throughput per rate, reset thr. below 10% success */
167 if (mrs->probability < MINSTREL_FRAC(10, 100))
168 mrs->cur_tp = 0;
169 else
170 mrs->cur_tp = mrs->probability * (1000000 / usecs);
171
172 /* Sample less often below the 10% chance of success.
173 * Sample less often above the 95% chance of success. */
174 if (mrs->probability > MINSTREL_FRAC(95, 100) ||
175 mrs->probability < MINSTREL_FRAC(10, 100)) {
176 mr->adjusted_retry_count = mrs->retry_count >> 1;
177 if (mr->adjusted_retry_count > 2)
178 mr->adjusted_retry_count = 2;
179 mr->sample_limit = 4;
180 } else {
181 mr->sample_limit = -1;
182 mr->adjusted_retry_count = mrs->retry_count;
183 }
184 if (!mr->adjusted_retry_count)
185 mr->adjusted_retry_count = 2;
186
187 minstrel_sort_best_tp_rates(mi, i, tmp_tp_rate);
188
189 /* To determine the most robust rate (max_prob_rate) used at
190 * 3rd mmr stage we distinct between two cases:
191 * (1) if any success probabilitiy >= 95%, out of those rates
192 * choose the maximum throughput rate as max_prob_rate
193 * (2) if all success probabilities < 95%, the rate with
194 * highest success probability is choosen as max_prob_rate */
195 if (mrs->probability >= MINSTREL_FRAC(95, 100)) {
196 if (mrs->cur_tp >= mi->r[tmp_prob_rate].stats.cur_tp)
197 tmp_prob_rate = i;
198 } else {
199 if (mrs->probability >= mi->r[tmp_prob_rate].stats.probability)
200 tmp_prob_rate = i;
201 }
202 }
203
204 /* Assign the new rate set */
205 memcpy(mi->max_tp_rate, tmp_tp_rate, sizeof(mi->max_tp_rate));
206 mi->max_prob_rate = tmp_prob_rate;
207
208 #ifdef CONFIG_MAC80211_DEBUGFS
209 /* use fixed index if set */
210 if (mp->fixed_rate_idx != -1) {
211 mi->max_tp_rate[0] = mp->fixed_rate_idx;
212 mi->max_tp_rate[1] = mp->fixed_rate_idx;
213 mi->max_prob_rate = mp->fixed_rate_idx;
214 }
215 #endif
216
217 /* Reset update timer */
218 mi->stats_update = jiffies;
219
220 minstrel_update_rates(mp, mi);
221 }
222
223 static void
224 minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband,
225 struct ieee80211_sta *sta, void *priv_sta,
226 struct sk_buff *skb)
227 {
228 struct minstrel_priv *mp = priv;
229 struct minstrel_sta_info *mi = priv_sta;
230 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
231 struct ieee80211_tx_rate *ar = info->status.rates;
232 int i, ndx;
233 int success;
234
235 success = !!(info->flags & IEEE80211_TX_STAT_ACK);
236
237 for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
238 if (ar[i].idx < 0)
239 break;
240
241 ndx = rix_to_ndx(mi, ar[i].idx);
242 if (ndx < 0)
243 continue;
244
245 mi->r[ndx].stats.attempts += ar[i].count;
246
247 if ((i != IEEE80211_TX_MAX_RATES - 1) && (ar[i + 1].idx < 0))
248 mi->r[ndx].stats.success += success;
249 }
250
251 if ((info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) && (i >= 0))
252 mi->sample_packets++;
253
254 if (mi->sample_deferred > 0)
255 mi->sample_deferred--;
256
257 if (time_after(jiffies, mi->stats_update +
258 (mp->update_interval * HZ) / 1000))
259 minstrel_update_stats(mp, mi);
260 }
261
262
263 static inline unsigned int
264 minstrel_get_retry_count(struct minstrel_rate *mr,
265 struct ieee80211_tx_info *info)
266 {
267 unsigned int retry = mr->adjusted_retry_count;
268
269 if (info->control.use_rts)
270 retry = max(2U, min(mr->stats.retry_count_rtscts, retry));
271 else if (info->control.use_cts_prot)
272 retry = max(2U, min(mr->retry_count_cts, retry));
273 return retry;
274 }
275
276
277 static int
278 minstrel_get_next_sample(struct minstrel_sta_info *mi)
279 {
280 unsigned int sample_ndx;
281 sample_ndx = SAMPLE_TBL(mi, mi->sample_row, mi->sample_column);
282 mi->sample_row++;
283 if ((int) mi->sample_row >= mi->n_rates) {
284 mi->sample_row = 0;
285 mi->sample_column++;
286 if (mi->sample_column >= SAMPLE_COLUMNS)
287 mi->sample_column = 0;
288 }
289 return sample_ndx;
290 }
291
292 static void
293 minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
294 void *priv_sta, struct ieee80211_tx_rate_control *txrc)
295 {
296 struct sk_buff *skb = txrc->skb;
297 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
298 struct minstrel_sta_info *mi = priv_sta;
299 struct minstrel_priv *mp = priv;
300 struct ieee80211_tx_rate *rate = &info->control.rates[0];
301 struct minstrel_rate *msr, *mr;
302 unsigned int ndx;
303 bool mrr_capable;
304 bool prev_sample;
305 int delta;
306 int sampling_ratio;
307
308 /* management/no-ack frames do not use rate control */
309 if (rate_control_send_low(sta, priv_sta, txrc))
310 return;
311
312 /* check multi-rate-retry capabilities & adjust lookaround_rate */
313 mrr_capable = mp->has_mrr &&
314 !txrc->rts &&
315 !txrc->bss_conf->use_cts_prot;
316 if (mrr_capable)
317 sampling_ratio = mp->lookaround_rate_mrr;
318 else
319 sampling_ratio = mp->lookaround_rate;
320
321 /* increase sum packet counter */
322 mi->total_packets++;
323
324 #ifdef CONFIG_MAC80211_DEBUGFS
325 if (mp->fixed_rate_idx != -1)
326 return;
327 #endif
328
329 delta = (mi->total_packets * sampling_ratio / 100) -
330 (mi->sample_packets + mi->sample_deferred / 2);
331
332 /* delta < 0: no sampling required */
333 prev_sample = mi->prev_sample;
334 mi->prev_sample = false;
335 if (delta < 0 || (!mrr_capable && prev_sample))
336 return;
337
338 if (mi->total_packets >= 10000) {
339 mi->sample_deferred = 0;
340 mi->sample_packets = 0;
341 mi->total_packets = 0;
342 } else if (delta > mi->n_rates * 2) {
343 /* With multi-rate retry, not every planned sample
344 * attempt actually gets used, due to the way the retry
345 * chain is set up - [max_tp,sample,prob,lowest] for
346 * sample_rate < max_tp.
347 *
348 * If there's too much sampling backlog and the link
349 * starts getting worse, minstrel would start bursting
350 * out lots of sampling frames, which would result
351 * in a large throughput loss. */
352 mi->sample_packets += (delta - mi->n_rates * 2);
353 }
354
355 /* get next random rate sample */
356 ndx = minstrel_get_next_sample(mi);
357 msr = &mi->r[ndx];
358 mr = &mi->r[mi->max_tp_rate[0]];
359
360 /* Decide if direct ( 1st mrr stage) or indirect (2nd mrr stage)
361 * rate sampling method should be used.
362 * Respect such rates that are not sampled for 20 interations.
363 */
364 if (mrr_capable &&
365 msr->perfect_tx_time > mr->perfect_tx_time &&
366 msr->stats.sample_skipped < 20) {
367 /* Only use IEEE80211_TX_CTL_RATE_CTRL_PROBE to mark
368 * packets that have the sampling rate deferred to the
369 * second MRR stage. Increase the sample counter only
370 * if the deferred sample rate was actually used.
371 * Use the sample_deferred counter to make sure that
372 * the sampling is not done in large bursts */
373 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
374 rate++;
375 mi->sample_deferred++;
376 } else {
377 if (!msr->sample_limit != 0)
378 return;
379
380 mi->sample_packets++;
381 if (msr->sample_limit > 0)
382 msr->sample_limit--;
383 }
384
385 /* If we're not using MRR and the sampling rate already
386 * has a probability of >95%, we shouldn't be attempting
387 * to use it, as this only wastes precious airtime */
388 if (!mrr_capable &&
389 (mi->r[ndx].stats.probability > MINSTREL_FRAC(95, 100)))
390 return;
391
392 mi->prev_sample = true;
393
394 rate->idx = mi->r[ndx].rix;
395 rate->count = minstrel_get_retry_count(&mi->r[ndx], info);
396 }
397
398
399 static void
400 calc_rate_durations(enum ieee80211_band band,
401 struct minstrel_rate *d,
402 struct ieee80211_rate *rate,
403 struct cfg80211_chan_def *chandef)
404 {
405 int erp = !!(rate->flags & IEEE80211_RATE_ERP_G);
406 int shift = ieee80211_chandef_get_shift(chandef);
407
408 d->perfect_tx_time = ieee80211_frame_duration(band, 1200,
409 DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
410 shift);
411 d->ack_time = ieee80211_frame_duration(band, 10,
412 DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
413 shift);
414 }
415
416 static void
417 init_sample_table(struct minstrel_sta_info *mi)
418 {
419 unsigned int i, col, new_idx;
420 u8 rnd[8];
421
422 mi->sample_column = 0;
423 mi->sample_row = 0;
424 memset(mi->sample_table, 0xff, SAMPLE_COLUMNS * mi->n_rates);
425
426 for (col = 0; col < SAMPLE_COLUMNS; col++) {
427 prandom_bytes(rnd, sizeof(rnd));
428 for (i = 0; i < mi->n_rates; i++) {
429 new_idx = (i + rnd[i & 7]) % mi->n_rates;
430 while (SAMPLE_TBL(mi, new_idx, col) != 0xff)
431 new_idx = (new_idx + 1) % mi->n_rates;
432
433 SAMPLE_TBL(mi, new_idx, col) = i;
434 }
435 }
436 }
437
438 static void
439 minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
440 struct cfg80211_chan_def *chandef,
441 struct ieee80211_sta *sta, void *priv_sta)
442 {
443 struct minstrel_sta_info *mi = priv_sta;
444 struct minstrel_priv *mp = priv;
445 struct ieee80211_rate *ctl_rate;
446 unsigned int i, n = 0;
447 unsigned int t_slot = 9; /* FIXME: get real slot time */
448 u32 rate_flags;
449
450 mi->sta = sta;
451 mi->lowest_rix = rate_lowest_index(sband, sta);
452 ctl_rate = &sband->bitrates[mi->lowest_rix];
453 mi->sp_ack_dur = ieee80211_frame_duration(sband->band, 10,
454 ctl_rate->bitrate,
455 !!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1,
456 ieee80211_chandef_get_shift(chandef));
457
458 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
459 memset(mi->max_tp_rate, 0, sizeof(mi->max_tp_rate));
460 mi->max_prob_rate = 0;
461
462 for (i = 0; i < sband->n_bitrates; i++) {
463 struct minstrel_rate *mr = &mi->r[n];
464 struct minstrel_rate_stats *mrs = &mi->r[n].stats;
465 unsigned int tx_time = 0, tx_time_cts = 0, tx_time_rtscts = 0;
466 unsigned int tx_time_single;
467 unsigned int cw = mp->cw_min;
468 int shift;
469
470 if (!rate_supported(sta, sband->band, i))
471 continue;
472 if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
473 continue;
474
475 n++;
476 memset(mr, 0, sizeof(*mr));
477 memset(mrs, 0, sizeof(*mrs));
478
479 mr->rix = i;
480 shift = ieee80211_chandef_get_shift(chandef);
481 mr->bitrate = DIV_ROUND_UP(sband->bitrates[i].bitrate,
482 (1 << shift) * 5);
483 calc_rate_durations(sband->band, mr, &sband->bitrates[i],
484 chandef);
485
486 /* calculate maximum number of retransmissions before
487 * fallback (based on maximum segment size) */
488 mr->sample_limit = -1;
489 mrs->retry_count = 1;
490 mr->retry_count_cts = 1;
491 mrs->retry_count_rtscts = 1;
492 tx_time = mr->perfect_tx_time + mi->sp_ack_dur;
493 do {
494 /* add one retransmission */
495 tx_time_single = mr->ack_time + mr->perfect_tx_time;
496
497 /* contention window */
498 tx_time_single += (t_slot * cw) >> 1;
499 cw = min((cw << 1) | 1, mp->cw_max);
500
501 tx_time += tx_time_single;
502 tx_time_cts += tx_time_single + mi->sp_ack_dur;
503 tx_time_rtscts += tx_time_single + 2 * mi->sp_ack_dur;
504 if ((tx_time_cts < mp->segment_size) &&
505 (mr->retry_count_cts < mp->max_retry))
506 mr->retry_count_cts++;
507 if ((tx_time_rtscts < mp->segment_size) &&
508 (mrs->retry_count_rtscts < mp->max_retry))
509 mrs->retry_count_rtscts++;
510 } while ((tx_time < mp->segment_size) &&
511 (++mr->stats.retry_count < mp->max_retry));
512 mr->adjusted_retry_count = mrs->retry_count;
513 if (!(sband->bitrates[i].flags & IEEE80211_RATE_ERP_G))
514 mr->retry_count_cts = mrs->retry_count;
515 }
516
517 for (i = n; i < sband->n_bitrates; i++) {
518 struct minstrel_rate *mr = &mi->r[i];
519 mr->rix = -1;
520 }
521
522 mi->n_rates = n;
523 mi->stats_update = jiffies;
524
525 init_sample_table(mi);
526 minstrel_update_rates(mp, mi);
527 }
528
529 static void *
530 minstrel_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
531 {
532 struct ieee80211_supported_band *sband;
533 struct minstrel_sta_info *mi;
534 struct minstrel_priv *mp = priv;
535 struct ieee80211_hw *hw = mp->hw;
536 int max_rates = 0;
537 int i;
538
539 mi = kzalloc(sizeof(struct minstrel_sta_info), gfp);
540 if (!mi)
541 return NULL;
542
543 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
544 sband = hw->wiphy->bands[i];
545 if (sband && sband->n_bitrates > max_rates)
546 max_rates = sband->n_bitrates;
547 }
548
549 mi->r = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
550 if (!mi->r)
551 goto error;
552
553 mi->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
554 if (!mi->sample_table)
555 goto error1;
556
557 mi->stats_update = jiffies;
558 return mi;
559
560 error1:
561 kfree(mi->r);
562 error:
563 kfree(mi);
564 return NULL;
565 }
566
567 static void
568 minstrel_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
569 {
570 struct minstrel_sta_info *mi = priv_sta;
571
572 kfree(mi->sample_table);
573 kfree(mi->r);
574 kfree(mi);
575 }
576
577 static void
578 minstrel_init_cck_rates(struct minstrel_priv *mp)
579 {
580 static const int bitrates[4] = { 10, 20, 55, 110 };
581 struct ieee80211_supported_band *sband;
582 u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
583 int i, j;
584
585 sband = mp->hw->wiphy->bands[IEEE80211_BAND_2GHZ];
586 if (!sband)
587 return;
588
589 for (i = 0, j = 0; i < sband->n_bitrates; i++) {
590 struct ieee80211_rate *rate = &sband->bitrates[i];
591
592 if (rate->flags & IEEE80211_RATE_ERP_G)
593 continue;
594
595 if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
596 continue;
597
598 for (j = 0; j < ARRAY_SIZE(bitrates); j++) {
599 if (rate->bitrate != bitrates[j])
600 continue;
601
602 mp->cck_rates[j] = i;
603 break;
604 }
605 }
606 }
607
608 static void *
609 minstrel_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
610 {
611 struct minstrel_priv *mp;
612
613 mp = kzalloc(sizeof(struct minstrel_priv), GFP_ATOMIC);
614 if (!mp)
615 return NULL;
616
617 /* contention window settings
618 * Just an approximation. Using the per-queue values would complicate
619 * the calculations and is probably unnecessary */
620 mp->cw_min = 15;
621 mp->cw_max = 1023;
622
623 /* number of packets (in %) to use for sampling other rates
624 * sample less often for non-mrr packets, because the overhead
625 * is much higher than with mrr */
626 mp->lookaround_rate = 5;
627 mp->lookaround_rate_mrr = 10;
628
629 /* maximum time that the hw is allowed to stay in one MRR segment */
630 mp->segment_size = 6000;
631
632 if (hw->max_rate_tries > 0)
633 mp->max_retry = hw->max_rate_tries;
634 else
635 /* safe default, does not necessarily have to match hw properties */
636 mp->max_retry = 7;
637
638 if (hw->max_rates >= 4)
639 mp->has_mrr = true;
640
641 mp->hw = hw;
642 mp->update_interval = 100;
643
644 #ifdef CONFIG_MAC80211_DEBUGFS
645 mp->fixed_rate_idx = (u32) -1;
646 mp->dbg_fixed_rate = debugfs_create_u32("fixed_rate_idx",
647 S_IRUGO | S_IWUGO, debugfsdir, &mp->fixed_rate_idx);
648 #endif
649
650 minstrel_init_cck_rates(mp);
651
652 return mp;
653 }
654
655 static void
656 minstrel_free(void *priv)
657 {
658 #ifdef CONFIG_MAC80211_DEBUGFS
659 debugfs_remove(((struct minstrel_priv *)priv)->dbg_fixed_rate);
660 #endif
661 kfree(priv);
662 }
663
664 static u32 minstrel_get_expected_throughput(void *priv_sta)
665 {
666 struct minstrel_sta_info *mi = priv_sta;
667 int idx = mi->max_tp_rate[0];
668
669 /* convert pkt per sec in kbps (1200 is the average pkt size used for
670 * computing cur_tp
671 */
672 return MINSTREL_TRUNC(mi->r[idx].stats.cur_tp) * 1200 * 8 / 1024;
673 }
674
675 const struct rate_control_ops mac80211_minstrel = {
676 .name = "minstrel",
677 .tx_status = minstrel_tx_status,
678 .get_rate = minstrel_get_rate,
679 .rate_init = minstrel_rate_init,
680 .alloc = minstrel_alloc,
681 .free = minstrel_free,
682 .alloc_sta = minstrel_alloc_sta,
683 .free_sta = minstrel_free_sta,
684 #ifdef CONFIG_MAC80211_DEBUGFS
685 .add_sta_debugfs = minstrel_add_sta_debugfs,
686 .remove_sta_debugfs = minstrel_remove_sta_debugfs,
687 #endif
688 .get_expected_throughput = minstrel_get_expected_throughput,
689 };
690
691 int __init
692 rc80211_minstrel_init(void)
693 {
694 return ieee80211_rate_control_register(&mac80211_minstrel);
695 }
696
697 void
698 rc80211_minstrel_exit(void)
699 {
700 ieee80211_rate_control_unregister(&mac80211_minstrel);
701 }
702
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