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Felix Fietkaucccf1292008-10-05 18:07:45 +02001/*
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090053#include <linux/slab.h>
Felix Fietkaucccf1292008-10-05 18:07:45 +020054#include <net/mac80211.h>
55#include "rate.h"
56#include "rc80211_minstrel.h"
57
58#define SAMPLE_COLUMNS 10
59#define SAMPLE_TBL(_mi, _idx, _col) \
60 _mi->sample_table[(_idx * SAMPLE_COLUMNS) + _col]
61
62/* convert mac80211 rate index to local array index */
63static inline int
64rix_to_ndx(struct minstrel_sta_info *mi, int rix)
65{
66 int i = rix;
67 for (i = rix; i >= 0; i--)
68 if (mi->r[i].rix == rix)
69 break;
Felix Fietkaucccf1292008-10-05 18:07:45 +020070 return i;
71}
72
Felix Fietkaucccf1292008-10-05 18:07:45 +020073static void
74minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
75{
76 u32 max_tp = 0, index_max_tp = 0, index_max_tp2 = 0;
77 u32 max_prob = 0, index_max_prob = 0;
78 u32 usecs;
79 u32 p;
80 int i;
81
82 mi->stats_update = jiffies;
83 for (i = 0; i < mi->n_rates; i++) {
84 struct minstrel_rate *mr = &mi->r[i];
85
86 usecs = mr->perfect_tx_time;
87 if (!usecs)
88 usecs = 1000000;
89
90 /* To avoid rounding issues, probabilities scale from 0 (0%)
91 * to 18000 (100%) */
92 if (mr->attempts) {
93 p = (mr->success * 18000) / mr->attempts;
94 mr->succ_hist += mr->success;
95 mr->att_hist += mr->attempts;
96 mr->cur_prob = p;
97 p = ((p * (100 - mp->ewma_level)) + (mr->probability *
98 mp->ewma_level)) / 100;
99 mr->probability = p;
100 mr->cur_tp = p * (1000000 / usecs);
101 }
102
103 mr->last_success = mr->success;
104 mr->last_attempts = mr->attempts;
105 mr->success = 0;
106 mr->attempts = 0;
107
108 /* Sample less often below the 10% chance of success.
109 * Sample less often above the 95% chance of success. */
110 if ((mr->probability > 17100) || (mr->probability < 1800)) {
111 mr->adjusted_retry_count = mr->retry_count >> 1;
112 if (mr->adjusted_retry_count > 2)
113 mr->adjusted_retry_count = 2;
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200114 mr->sample_limit = 4;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200115 } else {
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200116 mr->sample_limit = -1;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200117 mr->adjusted_retry_count = mr->retry_count;
118 }
119 if (!mr->adjusted_retry_count)
120 mr->adjusted_retry_count = 2;
121 }
122
123 for (i = 0; i < mi->n_rates; i++) {
124 struct minstrel_rate *mr = &mi->r[i];
125 if (max_tp < mr->cur_tp) {
126 index_max_tp = i;
127 max_tp = mr->cur_tp;
128 }
129 if (max_prob < mr->probability) {
130 index_max_prob = i;
131 max_prob = mr->probability;
132 }
133 }
134
135 max_tp = 0;
136 for (i = 0; i < mi->n_rates; i++) {
137 struct minstrel_rate *mr = &mi->r[i];
138
139 if (i == index_max_tp)
140 continue;
141
142 if (max_tp < mr->cur_tp) {
143 index_max_tp2 = i;
144 max_tp = mr->cur_tp;
145 }
146 }
147 mi->max_tp_rate = index_max_tp;
148 mi->max_tp_rate2 = index_max_tp2;
149 mi->max_prob_rate = index_max_prob;
150}
151
152static void
153minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband,
154 struct ieee80211_sta *sta, void *priv_sta,
155 struct sk_buff *skb)
156{
Johannes Berg8acbcdd2012-11-15 18:27:56 +0100157 struct minstrel_priv *mp = priv;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200158 struct minstrel_sta_info *mi = priv_sta;
159 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
Johannes Berge6a98542008-10-21 12:40:02 +0200160 struct ieee80211_tx_rate *ar = info->status.rates;
161 int i, ndx;
162 int success;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200163
Johannes Berge6a98542008-10-21 12:40:02 +0200164 success = !!(info->flags & IEEE80211_TX_STAT_ACK);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200165
Johannes Berge6a98542008-10-21 12:40:02 +0200166 for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
167 if (ar[i].idx < 0)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200168 break;
169
Johannes Berge6a98542008-10-21 12:40:02 +0200170 ndx = rix_to_ndx(mi, ar[i].idx);
Luciano Coelho3938b452009-07-03 08:25:08 +0300171 if (ndx < 0)
172 continue;
173
Johannes Berge6a98542008-10-21 12:40:02 +0200174 mi->r[ndx].attempts += ar[i].count;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200175
Javier Cardonabfc32e62009-08-17 17:15:55 -0700176 if ((i != IEEE80211_TX_MAX_RATES - 1) && (ar[i + 1].idx < 0))
Felix Fietkaucccf1292008-10-05 18:07:45 +0200177 mi->r[ndx].success += success;
178 }
179
180 if ((info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) && (i >= 0))
181 mi->sample_count++;
182
183 if (mi->sample_deferred > 0)
184 mi->sample_deferred--;
Johannes Berg8acbcdd2012-11-15 18:27:56 +0100185
186 if (time_after(jiffies, mi->stats_update +
187 (mp->update_interval * HZ) / 1000))
188 minstrel_update_stats(mp, mi);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200189}
190
191
192static inline unsigned int
193minstrel_get_retry_count(struct minstrel_rate *mr,
194 struct ieee80211_tx_info *info)
195{
196 unsigned int retry = mr->adjusted_retry_count;
197
Johannes Berge6a98542008-10-21 12:40:02 +0200198 if (info->control.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200199 retry = max(2U, min(mr->retry_count_rtscts, retry));
Johannes Berge6a98542008-10-21 12:40:02 +0200200 else if (info->control.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200201 retry = max(2U, min(mr->retry_count_cts, retry));
202 return retry;
203}
204
205
206static int
207minstrel_get_next_sample(struct minstrel_sta_info *mi)
208{
209 unsigned int sample_ndx;
210 sample_ndx = SAMPLE_TBL(mi, mi->sample_idx, mi->sample_column);
211 mi->sample_idx++;
Bob Copeland5ee58d72009-06-05 08:21:50 -0400212 if ((int) mi->sample_idx > (mi->n_rates - 2)) {
Felix Fietkaucccf1292008-10-05 18:07:45 +0200213 mi->sample_idx = 0;
214 mi->sample_column++;
215 if (mi->sample_column >= SAMPLE_COLUMNS)
216 mi->sample_column = 0;
217 }
218 return sample_ndx;
219}
220
Johannes Berg2df78162008-10-28 16:49:41 +0100221static void
Johannes Berge6a98542008-10-21 12:40:02 +0200222minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
223 void *priv_sta, struct ieee80211_tx_rate_control *txrc)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200224{
Johannes Berge6a98542008-10-21 12:40:02 +0200225 struct sk_buff *skb = txrc->skb;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200226 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
227 struct minstrel_sta_info *mi = priv_sta;
228 struct minstrel_priv *mp = priv;
Johannes Berge6a98542008-10-21 12:40:02 +0200229 struct ieee80211_tx_rate *ar = info->control.rates;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200230 unsigned int ndx, sample_ndx = 0;
231 bool mrr;
232 bool sample_slower = false;
233 bool sample = false;
234 int i, delta;
235 int mrr_ndx[3];
236 int sample_rate;
237
Luis R. Rodriguez4c6d4f52009-07-16 10:05:41 -0700238 if (rate_control_send_low(sta, priv_sta, txrc))
Felix Fietkaucccf1292008-10-05 18:07:45 +0200239 return;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200240
Johannes Berge6a98542008-10-21 12:40:02 +0200241 mrr = mp->has_mrr && !txrc->rts && !txrc->bss_conf->use_cts_prot;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200242
Felix Fietkaucccf1292008-10-05 18:07:45 +0200243 ndx = mi->max_tp_rate;
244
245 if (mrr)
246 sample_rate = mp->lookaround_rate_mrr;
247 else
248 sample_rate = mp->lookaround_rate;
249
250 mi->packet_count++;
251 delta = (mi->packet_count * sample_rate / 100) -
252 (mi->sample_count + mi->sample_deferred / 2);
253
254 /* delta > 0: sampling required */
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200255 if ((delta > 0) && (mrr || !mi->prev_sample)) {
256 struct minstrel_rate *msr;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200257 if (mi->packet_count >= 10000) {
258 mi->sample_deferred = 0;
259 mi->sample_count = 0;
260 mi->packet_count = 0;
261 } else if (delta > mi->n_rates * 2) {
262 /* With multi-rate retry, not every planned sample
263 * attempt actually gets used, due to the way the retry
264 * chain is set up - [max_tp,sample,prob,lowest] for
265 * sample_rate < max_tp.
266 *
267 * If there's too much sampling backlog and the link
268 * starts getting worse, minstrel would start bursting
269 * out lots of sampling frames, which would result
270 * in a large throughput loss. */
271 mi->sample_count += (delta - mi->n_rates * 2);
272 }
273
274 sample_ndx = minstrel_get_next_sample(mi);
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200275 msr = &mi->r[sample_ndx];
Felix Fietkaucccf1292008-10-05 18:07:45 +0200276 sample = true;
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200277 sample_slower = mrr && (msr->perfect_tx_time >
Felix Fietkaucccf1292008-10-05 18:07:45 +0200278 mi->r[ndx].perfect_tx_time);
279
280 if (!sample_slower) {
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200281 if (msr->sample_limit != 0) {
282 ndx = sample_ndx;
283 mi->sample_count++;
284 if (msr->sample_limit > 0)
285 msr->sample_limit--;
286 } else {
287 sample = false;
288 }
Felix Fietkaucccf1292008-10-05 18:07:45 +0200289 } else {
290 /* Only use IEEE80211_TX_CTL_RATE_CTRL_PROBE to mark
291 * packets that have the sampling rate deferred to the
292 * second MRR stage. Increase the sample counter only
293 * if the deferred sample rate was actually used.
294 * Use the sample_deferred counter to make sure that
295 * the sampling is not done in large bursts */
296 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
297 mi->sample_deferred++;
298 }
299 }
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200300 mi->prev_sample = sample;
301
302 /* If we're not using MRR and the sampling rate already
303 * has a probability of >95%, we shouldn't be attempting
304 * to use it, as this only wastes precious airtime */
305 if (!mrr && sample && (mi->r[ndx].probability > 17100))
306 ndx = mi->max_tp_rate;
307
Johannes Berge6a98542008-10-21 12:40:02 +0200308 ar[0].idx = mi->r[ndx].rix;
309 ar[0].count = minstrel_get_retry_count(&mi->r[ndx], info);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200310
311 if (!mrr) {
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200312 if (!sample)
313 ar[0].count = mp->max_retry;
Johannes Berge6a98542008-10-21 12:40:02 +0200314 ar[1].idx = mi->lowest_rix;
315 ar[1].count = mp->max_retry;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200316 return;
317 }
318
319 /* MRR setup */
320 if (sample) {
321 if (sample_slower)
322 mrr_ndx[0] = sample_ndx;
323 else
324 mrr_ndx[0] = mi->max_tp_rate;
325 } else {
326 mrr_ndx[0] = mi->max_tp_rate2;
327 }
328 mrr_ndx[1] = mi->max_prob_rate;
329 mrr_ndx[2] = 0;
Johannes Berge6a98542008-10-21 12:40:02 +0200330 for (i = 1; i < 4; i++) {
331 ar[i].idx = mi->r[mrr_ndx[i - 1]].rix;
332 ar[i].count = mi->r[mrr_ndx[i - 1]].adjusted_retry_count;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200333 }
334}
335
336
337static void
Michal Kazior4ee73f32012-04-11 08:47:56 +0200338calc_rate_durations(enum ieee80211_band band,
339 struct minstrel_rate *d,
Patrick Kelle868a5f72011-11-10 15:13:11 +0100340 struct ieee80211_rate *rate)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200341{
342 int erp = !!(rate->flags & IEEE80211_RATE_ERP_G);
343
Michal Kazior4ee73f32012-04-11 08:47:56 +0200344 d->perfect_tx_time = ieee80211_frame_duration(band, 1200,
Felix Fietkaucccf1292008-10-05 18:07:45 +0200345 rate->bitrate, erp, 1);
Michal Kazior4ee73f32012-04-11 08:47:56 +0200346 d->ack_time = ieee80211_frame_duration(band, 10,
Felix Fietkaucccf1292008-10-05 18:07:45 +0200347 rate->bitrate, erp, 1);
348}
349
350static void
351init_sample_table(struct minstrel_sta_info *mi)
352{
353 unsigned int i, col, new_idx;
354 unsigned int n_srates = mi->n_rates - 1;
355 u8 rnd[8];
356
357 mi->sample_column = 0;
358 mi->sample_idx = 0;
359 memset(mi->sample_table, 0, SAMPLE_COLUMNS * mi->n_rates);
360
361 for (col = 0; col < SAMPLE_COLUMNS; col++) {
362 for (i = 0; i < n_srates; i++) {
363 get_random_bytes(rnd, sizeof(rnd));
364 new_idx = (i + rnd[i & 7]) % n_srates;
365
366 while (SAMPLE_TBL(mi, new_idx, col) != 0)
367 new_idx = (new_idx + 1) % n_srates;
368
369 /* Don't sample the slowest rate (i.e. slowest base
370 * rate). We must presume that the slowest rate works
371 * fine, or else other management frames will also be
372 * failing and the link will break */
373 SAMPLE_TBL(mi, new_idx, col) = i + 1;
374 }
375 }
376}
377
378static void
379minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
380 struct ieee80211_sta *sta, void *priv_sta)
381{
382 struct minstrel_sta_info *mi = priv_sta;
383 struct minstrel_priv *mp = priv;
Christian Lamparterd57854b2008-12-22 15:35:31 +0100384 struct ieee80211_rate *ctl_rate;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200385 unsigned int i, n = 0;
386 unsigned int t_slot = 9; /* FIXME: get real slot time */
387
388 mi->lowest_rix = rate_lowest_index(sband, sta);
Christian Lamparterd57854b2008-12-22 15:35:31 +0100389 ctl_rate = &sband->bitrates[mi->lowest_rix];
Michal Kazior4ee73f32012-04-11 08:47:56 +0200390 mi->sp_ack_dur = ieee80211_frame_duration(sband->band, 10,
391 ctl_rate->bitrate,
Christian Lamparterd57854b2008-12-22 15:35:31 +0100392 !!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200393
394 for (i = 0; i < sband->n_bitrates; i++) {
395 struct minstrel_rate *mr = &mi->r[n];
396 unsigned int tx_time = 0, tx_time_cts = 0, tx_time_rtscts = 0;
397 unsigned int tx_time_single;
398 unsigned int cw = mp->cw_min;
399
400 if (!rate_supported(sta, sband->band, i))
401 continue;
402 n++;
403 memset(mr, 0, sizeof(*mr));
404
405 mr->rix = i;
406 mr->bitrate = sband->bitrates[i].bitrate / 5;
Michal Kazior4ee73f32012-04-11 08:47:56 +0200407 calc_rate_durations(sband->band, mr, &sband->bitrates[i]);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200408
409 /* calculate maximum number of retransmissions before
410 * fallback (based on maximum segment size) */
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200411 mr->sample_limit = -1;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200412 mr->retry_count = 1;
413 mr->retry_count_cts = 1;
414 mr->retry_count_rtscts = 1;
415 tx_time = mr->perfect_tx_time + mi->sp_ack_dur;
416 do {
417 /* add one retransmission */
418 tx_time_single = mr->ack_time + mr->perfect_tx_time;
419
420 /* contention window */
Daniel Halperin8fddddf2011-05-10 19:00:45 -0700421 tx_time_single += (t_slot * cw) >> 1;
422 cw = min((cw << 1) | 1, mp->cw_max);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200423
424 tx_time += tx_time_single;
425 tx_time_cts += tx_time_single + mi->sp_ack_dur;
426 tx_time_rtscts += tx_time_single + 2 * mi->sp_ack_dur;
427 if ((tx_time_cts < mp->segment_size) &&
428 (mr->retry_count_cts < mp->max_retry))
429 mr->retry_count_cts++;
430 if ((tx_time_rtscts < mp->segment_size) &&
431 (mr->retry_count_rtscts < mp->max_retry))
432 mr->retry_count_rtscts++;
433 } while ((tx_time < mp->segment_size) &&
434 (++mr->retry_count < mp->max_retry));
435 mr->adjusted_retry_count = mr->retry_count;
436 }
437
438 for (i = n; i < sband->n_bitrates; i++) {
439 struct minstrel_rate *mr = &mi->r[i];
440 mr->rix = -1;
441 }
442
443 mi->n_rates = n;
444 mi->stats_update = jiffies;
445
446 init_sample_table(mi);
447}
448
449static void *
450minstrel_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
451{
452 struct ieee80211_supported_band *sband;
453 struct minstrel_sta_info *mi;
454 struct minstrel_priv *mp = priv;
455 struct ieee80211_hw *hw = mp->hw;
456 int max_rates = 0;
457 int i;
458
459 mi = kzalloc(sizeof(struct minstrel_sta_info), gfp);
460 if (!mi)
461 return NULL;
462
463 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
Jiri Slaby8e532172009-05-04 18:04:55 +0200464 sband = hw->wiphy->bands[i];
John W. Linville621ad7c2009-05-05 15:18:26 -0400465 if (sband && sband->n_bitrates > max_rates)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200466 max_rates = sband->n_bitrates;
467 }
468
469 mi->r = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
470 if (!mi->r)
471 goto error;
472
473 mi->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
474 if (!mi->sample_table)
475 goto error1;
476
477 mi->stats_update = jiffies;
478 return mi;
479
480error1:
481 kfree(mi->r);
482error:
483 kfree(mi);
484 return NULL;
485}
486
487static void
488minstrel_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
489{
490 struct minstrel_sta_info *mi = priv_sta;
491
492 kfree(mi->sample_table);
493 kfree(mi->r);
494 kfree(mi);
495}
496
Felix Fietkaua0497f92013-02-13 10:51:08 +0100497static void
498minstrel_init_cck_rates(struct minstrel_priv *mp)
499{
500 static const int bitrates[4] = { 10, 20, 55, 110 };
501 struct ieee80211_supported_band *sband;
502 int i, j;
503
504 sband = mp->hw->wiphy->bands[IEEE80211_BAND_2GHZ];
505 if (!sband)
506 return;
507
508 for (i = 0, j = 0; i < sband->n_bitrates; i++) {
509 struct ieee80211_rate *rate = &sband->bitrates[i];
510
511 if (rate->flags & IEEE80211_RATE_ERP_G)
512 continue;
513
514 for (j = 0; j < ARRAY_SIZE(bitrates); j++) {
515 if (rate->bitrate != bitrates[j])
516 continue;
517
518 mp->cck_rates[j] = i;
519 break;
520 }
521 }
522}
523
Felix Fietkaucccf1292008-10-05 18:07:45 +0200524static void *
525minstrel_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
526{
527 struct minstrel_priv *mp;
528
529 mp = kzalloc(sizeof(struct minstrel_priv), GFP_ATOMIC);
530 if (!mp)
531 return NULL;
532
533 /* contention window settings
534 * Just an approximation. Using the per-queue values would complicate
535 * the calculations and is probably unnecessary */
536 mp->cw_min = 15;
537 mp->cw_max = 1023;
538
539 /* number of packets (in %) to use for sampling other rates
540 * sample less often for non-mrr packets, because the overhead
541 * is much higher than with mrr */
542 mp->lookaround_rate = 5;
543 mp->lookaround_rate_mrr = 10;
544
545 /* moving average weight for EWMA */
546 mp->ewma_level = 75;
547
548 /* maximum time that the hw is allowed to stay in one MRR segment */
549 mp->segment_size = 6000;
550
Johannes Berge6a98542008-10-21 12:40:02 +0200551 if (hw->max_rate_tries > 0)
552 mp->max_retry = hw->max_rate_tries;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200553 else
554 /* safe default, does not necessarily have to match hw properties */
555 mp->max_retry = 7;
556
Johannes Berge6a98542008-10-21 12:40:02 +0200557 if (hw->max_rates >= 4)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200558 mp->has_mrr = true;
559
560 mp->hw = hw;
561 mp->update_interval = 100;
562
Zefir Kurtisi24f75802011-05-20 20:29:17 +0200563#ifdef CONFIG_MAC80211_DEBUGFS
564 mp->fixed_rate_idx = (u32) -1;
565 mp->dbg_fixed_rate = debugfs_create_u32("fixed_rate_idx",
566 S_IRUGO | S_IWUGO, debugfsdir, &mp->fixed_rate_idx);
567#endif
568
Felix Fietkaua0497f92013-02-13 10:51:08 +0100569 minstrel_init_cck_rates(mp);
570
Felix Fietkaucccf1292008-10-05 18:07:45 +0200571 return mp;
572}
573
574static void
575minstrel_free(void *priv)
576{
Zefir Kurtisi24f75802011-05-20 20:29:17 +0200577#ifdef CONFIG_MAC80211_DEBUGFS
578 debugfs_remove(((struct minstrel_priv *)priv)->dbg_fixed_rate);
579#endif
Felix Fietkaucccf1292008-10-05 18:07:45 +0200580 kfree(priv);
581}
582
Felix Fietkaueae44752010-03-01 22:21:40 +0100583struct rate_control_ops mac80211_minstrel = {
Felix Fietkaucccf1292008-10-05 18:07:45 +0200584 .name = "minstrel",
585 .tx_status = minstrel_tx_status,
586 .get_rate = minstrel_get_rate,
587 .rate_init = minstrel_rate_init,
Felix Fietkaucccf1292008-10-05 18:07:45 +0200588 .alloc = minstrel_alloc,
589 .free = minstrel_free,
590 .alloc_sta = minstrel_alloc_sta,
591 .free_sta = minstrel_free_sta,
592#ifdef CONFIG_MAC80211_DEBUGFS
593 .add_sta_debugfs = minstrel_add_sta_debugfs,
594 .remove_sta_debugfs = minstrel_remove_sta_debugfs,
595#endif
596};
597
598int __init
599rc80211_minstrel_init(void)
600{
601 return ieee80211_rate_control_register(&mac80211_minstrel);
602}
603
604void
605rc80211_minstrel_exit(void)
606{
607 ieee80211_rate_control_unregister(&mac80211_minstrel);
608}
609