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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
Felix Fietkaucccf1292008-10-05 18:07:45 +020058#define SAMPLE_TBL(_mi, _idx, _col) \
59 _mi->sample_table[(_idx * SAMPLE_COLUMNS) + _col]
60
61/* convert mac80211 rate index to local array index */
62static inline int
63rix_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;
Felix Fietkaucccf1292008-10-05 18:07:45 +020069 return i;
70}
71
Thomas Huehn2ff2b692013-03-04 23:30:07 +010072/* find & sort topmost throughput rates */
73static inline void
74minstrel_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].cur_tp > mi->r[tp_list[j - 1]].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
Felix Fietkaucccf1292008-10-05 18:07:45 +020086static void
Felix Fietkau06d961a2013-04-22 16:14:43 +020087minstrel_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->retry_count_rtscts;
96}
97
98static void
99minstrel_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
130static void
Felix Fietkaucccf1292008-10-05 18:07:45 +0200131minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
132{
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100133 u8 tmp_tp_rate[MAX_THR_RATES];
134 u8 tmp_prob_rate = 0;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200135 u32 usecs;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200136 int i;
137
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100138 for (i=0; i < MAX_THR_RATES; i++)
139 tmp_tp_rate[i] = 0;
140
Felix Fietkaucccf1292008-10-05 18:07:45 +0200141 for (i = 0; i < mi->n_rates; i++) {
142 struct minstrel_rate *mr = &mi->r[i];
143
144 usecs = mr->perfect_tx_time;
145 if (!usecs)
146 usecs = 1000000;
147
Thomas Huehn1e9c27d2013-03-04 23:30:04 +0100148 if (unlikely(mr->attempts > 0)) {
149 mr->sample_skipped = 0;
Thomas Huehnc8ca8c22013-03-04 23:30:02 +0100150 mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200151 mr->succ_hist += mr->success;
152 mr->att_hist += mr->attempts;
Thomas Huehna512d4b2013-03-04 23:30:01 +0100153 mr->probability = minstrel_ewma(mr->probability,
154 mr->cur_prob,
155 EWMA_LEVEL);
Thomas Huehn1e9c27d2013-03-04 23:30:04 +0100156 } else
157 mr->sample_skipped++;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200158
159 mr->last_success = mr->success;
160 mr->last_attempts = mr->attempts;
161 mr->success = 0;
162 mr->attempts = 0;
163
Thomas Huehndb8c5ee2013-03-04 23:30:06 +0100164 /* Update throughput per rate, reset thr. below 10% success */
165 if (mr->probability < MINSTREL_FRAC(10, 100))
166 mr->cur_tp = 0;
167 else
168 mr->cur_tp = mr->probability * (1000000 / usecs);
169
Felix Fietkaucccf1292008-10-05 18:07:45 +0200170 /* Sample less often below the 10% chance of success.
171 * Sample less often above the 95% chance of success. */
Thomas Huehnc8ca8c22013-03-04 23:30:02 +0100172 if (mr->probability > MINSTREL_FRAC(95, 100) ||
173 mr->probability < MINSTREL_FRAC(10, 100)) {
Felix Fietkaucccf1292008-10-05 18:07:45 +0200174 mr->adjusted_retry_count = mr->retry_count >> 1;
175 if (mr->adjusted_retry_count > 2)
176 mr->adjusted_retry_count = 2;
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200177 mr->sample_limit = 4;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200178 } else {
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200179 mr->sample_limit = -1;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200180 mr->adjusted_retry_count = mr->retry_count;
181 }
182 if (!mr->adjusted_retry_count)
183 mr->adjusted_retry_count = 2;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200184
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100185 minstrel_sort_best_tp_rates(mi, i, tmp_tp_rate);
186
187 /* To determine the most robust rate (max_prob_rate) used at
188 * 3rd mmr stage we distinct between two cases:
189 * (1) if any success probabilitiy >= 95%, out of those rates
190 * choose the maximum throughput rate as max_prob_rate
191 * (2) if all success probabilities < 95%, the rate with
192 * highest success probability is choosen as max_prob_rate */
193 if (mr->probability >= MINSTREL_FRAC(95,100)) {
194 if (mr->cur_tp >= mi->r[tmp_prob_rate].cur_tp)
195 tmp_prob_rate = i;
196 } else {
197 if (mr->probability >= mi->r[tmp_prob_rate].probability)
198 tmp_prob_rate = i;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200199 }
200 }
201
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100202 /* Assign the new rate set */
203 memcpy(mi->max_tp_rate, tmp_tp_rate, sizeof(mi->max_tp_rate));
204 mi->max_prob_rate = tmp_prob_rate;
Thomas Huehn8f157612013-03-04 23:30:03 +0100205
Lorenzo Bianconi45966ae2013-08-27 16:59:46 +0200206#ifdef CONFIG_MAC80211_DEBUGFS
207 /* use fixed index if set */
208 if (mp->fixed_rate_idx != -1) {
209 mi->max_tp_rate[0] = mp->fixed_rate_idx;
210 mi->max_tp_rate[1] = mp->fixed_rate_idx;
211 mi->max_prob_rate = mp->fixed_rate_idx;
212 }
213#endif
214
Thomas Huehn8f157612013-03-04 23:30:03 +0100215 /* Reset update timer */
216 mi->stats_update = jiffies;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200217
218 minstrel_update_rates(mp, mi);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200219}
220
221static void
222minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband,
223 struct ieee80211_sta *sta, void *priv_sta,
224 struct sk_buff *skb)
225{
Johannes Berg8acbcdd2012-11-15 18:27:56 +0100226 struct minstrel_priv *mp = priv;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200227 struct minstrel_sta_info *mi = priv_sta;
228 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
Johannes Berge6a98542008-10-21 12:40:02 +0200229 struct ieee80211_tx_rate *ar = info->status.rates;
230 int i, ndx;
231 int success;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200232
Johannes Berge6a98542008-10-21 12:40:02 +0200233 success = !!(info->flags & IEEE80211_TX_STAT_ACK);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200234
Johannes Berge6a98542008-10-21 12:40:02 +0200235 for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
236 if (ar[i].idx < 0)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200237 break;
238
Johannes Berge6a98542008-10-21 12:40:02 +0200239 ndx = rix_to_ndx(mi, ar[i].idx);
Luciano Coelho3938b452009-07-03 08:25:08 +0300240 if (ndx < 0)
241 continue;
242
Johannes Berge6a98542008-10-21 12:40:02 +0200243 mi->r[ndx].attempts += ar[i].count;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200244
Javier Cardonabfc32e62009-08-17 17:15:55 -0700245 if ((i != IEEE80211_TX_MAX_RATES - 1) && (ar[i + 1].idx < 0))
Felix Fietkaucccf1292008-10-05 18:07:45 +0200246 mi->r[ndx].success += success;
247 }
248
249 if ((info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) && (i >= 0))
250 mi->sample_count++;
251
252 if (mi->sample_deferred > 0)
253 mi->sample_deferred--;
Johannes Berg8acbcdd2012-11-15 18:27:56 +0100254
255 if (time_after(jiffies, mi->stats_update +
256 (mp->update_interval * HZ) / 1000))
257 minstrel_update_stats(mp, mi);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200258}
259
260
261static inline unsigned int
262minstrel_get_retry_count(struct minstrel_rate *mr,
263 struct ieee80211_tx_info *info)
264{
265 unsigned int retry = mr->adjusted_retry_count;
266
Felix Fietkau991fec02013-04-16 13:38:43 +0200267 if (info->control.use_rts)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200268 retry = max(2U, min(mr->retry_count_rtscts, retry));
Felix Fietkau991fec02013-04-16 13:38:43 +0200269 else if (info->control.use_cts_prot)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200270 retry = max(2U, min(mr->retry_count_cts, retry));
271 return retry;
272}
273
274
275static int
276minstrel_get_next_sample(struct minstrel_sta_info *mi)
277{
278 unsigned int sample_ndx;
Thomas Huehn8f157612013-03-04 23:30:03 +0100279 sample_ndx = SAMPLE_TBL(mi, mi->sample_row, mi->sample_column);
280 mi->sample_row++;
Thomas Huehnf744bf82013-03-04 23:30:05 +0100281 if ((int) mi->sample_row >= mi->n_rates) {
Thomas Huehn8f157612013-03-04 23:30:03 +0100282 mi->sample_row = 0;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200283 mi->sample_column++;
284 if (mi->sample_column >= SAMPLE_COLUMNS)
285 mi->sample_column = 0;
286 }
287 return sample_ndx;
288}
289
Johannes Berg2df78162008-10-28 16:49:41 +0100290static void
Johannes Berge6a98542008-10-21 12:40:02 +0200291minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
292 void *priv_sta, struct ieee80211_tx_rate_control *txrc)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200293{
Johannes Berge6a98542008-10-21 12:40:02 +0200294 struct sk_buff *skb = txrc->skb;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200295 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
296 struct minstrel_sta_info *mi = priv_sta;
297 struct minstrel_priv *mp = priv;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200298 struct ieee80211_tx_rate *rate = &info->control.rates[0];
299 struct minstrel_rate *msr, *mr;
300 unsigned int ndx;
Thomas Huehn8f157612013-03-04 23:30:03 +0100301 bool mrr_capable;
Felix Fietkau5c9fc932013-07-15 14:35:06 +0200302 bool prev_sample;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200303 int delta;
Thomas Huehn8f157612013-03-04 23:30:03 +0100304 int sampling_ratio;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200305
Thomas Huehn8f157612013-03-04 23:30:03 +0100306 /* management/no-ack frames do not use rate control */
Luis R. Rodriguez4c6d4f52009-07-16 10:05:41 -0700307 if (rate_control_send_low(sta, priv_sta, txrc))
Felix Fietkaucccf1292008-10-05 18:07:45 +0200308 return;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200309
Thomas Huehn8f157612013-03-04 23:30:03 +0100310 /* check multi-rate-retry capabilities & adjust lookaround_rate */
311 mrr_capable = mp->has_mrr &&
312 !txrc->rts &&
313 !txrc->bss_conf->use_cts_prot;
314 if (mrr_capable)
315 sampling_ratio = mp->lookaround_rate_mrr;
316 else
317 sampling_ratio = mp->lookaround_rate;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200318
Thomas Huehn8f157612013-03-04 23:30:03 +0100319 /* increase sum packet counter */
Felix Fietkaucccf1292008-10-05 18:07:45 +0200320 mi->packet_count++;
Thomas Huehn8f157612013-03-04 23:30:03 +0100321
Lorenzo Bianconi45966ae2013-08-27 16:59:46 +0200322#ifdef CONFIG_MAC80211_DEBUGFS
323 if (mp->fixed_rate_idx != -1)
324 return;
325#endif
326
Thomas Huehn8f157612013-03-04 23:30:03 +0100327 delta = (mi->packet_count * sampling_ratio / 100) -
Felix Fietkaucccf1292008-10-05 18:07:45 +0200328 (mi->sample_count + mi->sample_deferred / 2);
329
Felix Fietkau06d961a2013-04-22 16:14:43 +0200330 /* delta < 0: no sampling required */
Felix Fietkau5c9fc932013-07-15 14:35:06 +0200331 prev_sample = mi->prev_sample;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200332 mi->prev_sample = false;
333 if (delta < 0 || (!mrr_capable && prev_sample))
334 return;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200335
Felix Fietkau06d961a2013-04-22 16:14:43 +0200336 if (mi->packet_count >= 10000) {
337 mi->sample_deferred = 0;
338 mi->sample_count = 0;
339 mi->packet_count = 0;
340 } else if (delta > mi->n_rates * 2) {
341 /* With multi-rate retry, not every planned sample
342 * attempt actually gets used, due to the way the retry
343 * chain is set up - [max_tp,sample,prob,lowest] for
344 * sample_rate < max_tp.
345 *
346 * If there's too much sampling backlog and the link
347 * starts getting worse, minstrel would start bursting
348 * out lots of sampling frames, which would result
349 * in a large throughput loss. */
350 mi->sample_count += (delta - mi->n_rates * 2);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200351 }
Felix Fietkau06d961a2013-04-22 16:14:43 +0200352
353 /* get next random rate sample */
354 ndx = minstrel_get_next_sample(mi);
355 msr = &mi->r[ndx];
356 mr = &mi->r[mi->max_tp_rate[0]];
357
358 /* Decide if direct ( 1st mrr stage) or indirect (2nd mrr stage)
359 * rate sampling method should be used.
360 * Respect such rates that are not sampled for 20 interations.
361 */
362 if (mrr_capable &&
363 msr->perfect_tx_time > mr->perfect_tx_time &&
364 msr->sample_skipped < 20) {
365 /* Only use IEEE80211_TX_CTL_RATE_CTRL_PROBE to mark
366 * packets that have the sampling rate deferred to the
367 * second MRR stage. Increase the sample counter only
368 * if the deferred sample rate was actually used.
369 * Use the sample_deferred counter to make sure that
370 * the sampling is not done in large bursts */
371 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
372 rate++;
373 mi->sample_deferred++;
374 } else {
375 if (!msr->sample_limit != 0)
376 return;
377
378 mi->sample_count++;
379 if (msr->sample_limit > 0)
380 msr->sample_limit--;
381 }
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200382
383 /* If we're not using MRR and the sampling rate already
384 * has a probability of >95%, we shouldn't be attempting
385 * to use it, as this only wastes precious airtime */
Felix Fietkau06d961a2013-04-22 16:14:43 +0200386 if (!mrr_capable &&
Thomas Huehn8f157612013-03-04 23:30:03 +0100387 (mi->r[ndx].probability > MINSTREL_FRAC(95, 100)))
Felix Fietkaucccf1292008-10-05 18:07:45 +0200388 return;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200389
Felix Fietkau06d961a2013-04-22 16:14:43 +0200390 mi->prev_sample = true;
Thomas Huehn8f157612013-03-04 23:30:03 +0100391
Felix Fietkau06d961a2013-04-22 16:14:43 +0200392 rate->idx = mi->r[ndx].rix;
393 rate->count = minstrel_get_retry_count(&mi->r[ndx], info);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200394}
395
396
397static void
Michal Kazior4ee73f32012-04-11 08:47:56 +0200398calc_rate_durations(enum ieee80211_band band,
399 struct minstrel_rate *d,
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200400 struct ieee80211_rate *rate,
401 struct cfg80211_chan_def *chandef)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200402{
403 int erp = !!(rate->flags & IEEE80211_RATE_ERP_G);
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200404 int shift = ieee80211_chandef_get_shift(chandef);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200405
Michal Kazior4ee73f32012-04-11 08:47:56 +0200406 d->perfect_tx_time = ieee80211_frame_duration(band, 1200,
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200407 DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
408 shift);
Michal Kazior4ee73f32012-04-11 08:47:56 +0200409 d->ack_time = ieee80211_frame_duration(band, 10,
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200410 DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
411 shift);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200412}
413
414static void
415init_sample_table(struct minstrel_sta_info *mi)
416{
417 unsigned int i, col, new_idx;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200418 u8 rnd[8];
419
420 mi->sample_column = 0;
Thomas Huehn8f157612013-03-04 23:30:03 +0100421 mi->sample_row = 0;
Thomas Huehnf744bf82013-03-04 23:30:05 +0100422 memset(mi->sample_table, 0xff, SAMPLE_COLUMNS * mi->n_rates);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200423
424 for (col = 0; col < SAMPLE_COLUMNS; col++) {
Karl Beldanf7d8ad82013-11-13 10:54:19 +0100425 prandom_bytes(rnd, sizeof(rnd));
Thomas Huehnf744bf82013-03-04 23:30:05 +0100426 for (i = 0; i < mi->n_rates; i++) {
Thomas Huehnf744bf82013-03-04 23:30:05 +0100427 new_idx = (i + rnd[i & 7]) % mi->n_rates;
Thomas Huehnf744bf82013-03-04 23:30:05 +0100428 while (SAMPLE_TBL(mi, new_idx, col) != 0xff)
429 new_idx = (new_idx + 1) % mi->n_rates;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200430
Thomas Huehnf744bf82013-03-04 23:30:05 +0100431 SAMPLE_TBL(mi, new_idx, col) = i;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200432 }
433 }
434}
435
436static void
437minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
Simon Wunderlich3de805c2013-07-08 16:55:50 +0200438 struct cfg80211_chan_def *chandef,
439 struct ieee80211_sta *sta, void *priv_sta)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200440{
441 struct minstrel_sta_info *mi = priv_sta;
442 struct minstrel_priv *mp = priv;
Christian Lamparterd57854b2008-12-22 15:35:31 +0100443 struct ieee80211_rate *ctl_rate;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200444 unsigned int i, n = 0;
445 unsigned int t_slot = 9; /* FIXME: get real slot time */
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200446 u32 rate_flags;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200447
Felix Fietkau06d961a2013-04-22 16:14:43 +0200448 mi->sta = sta;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200449 mi->lowest_rix = rate_lowest_index(sband, sta);
Christian Lamparterd57854b2008-12-22 15:35:31 +0100450 ctl_rate = &sband->bitrates[mi->lowest_rix];
Michal Kazior4ee73f32012-04-11 08:47:56 +0200451 mi->sp_ack_dur = ieee80211_frame_duration(sband->band, 10,
452 ctl_rate->bitrate,
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200453 !!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1,
454 ieee80211_chandef_get_shift(chandef));
Felix Fietkaucccf1292008-10-05 18:07:45 +0200455
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200456 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
Felix Fietkau06d961a2013-04-22 16:14:43 +0200457 memset(mi->max_tp_rate, 0, sizeof(mi->max_tp_rate));
458 mi->max_prob_rate = 0;
459
Felix Fietkaucccf1292008-10-05 18:07:45 +0200460 for (i = 0; i < sband->n_bitrates; i++) {
461 struct minstrel_rate *mr = &mi->r[n];
462 unsigned int tx_time = 0, tx_time_cts = 0, tx_time_rtscts = 0;
463 unsigned int tx_time_single;
464 unsigned int cw = mp->cw_min;
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200465 int shift;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200466
467 if (!rate_supported(sta, sband->band, i))
468 continue;
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200469 if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
470 continue;
471
Felix Fietkaucccf1292008-10-05 18:07:45 +0200472 n++;
473 memset(mr, 0, sizeof(*mr));
474
475 mr->rix = i;
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200476 shift = ieee80211_chandef_get_shift(chandef);
477 mr->bitrate = DIV_ROUND_UP(sband->bitrates[i].bitrate,
478 (1 << shift) * 5);
479 calc_rate_durations(sband->band, mr, &sband->bitrates[i],
480 chandef);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200481
482 /* calculate maximum number of retransmissions before
483 * fallback (based on maximum segment size) */
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200484 mr->sample_limit = -1;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200485 mr->retry_count = 1;
486 mr->retry_count_cts = 1;
487 mr->retry_count_rtscts = 1;
488 tx_time = mr->perfect_tx_time + mi->sp_ack_dur;
489 do {
490 /* add one retransmission */
491 tx_time_single = mr->ack_time + mr->perfect_tx_time;
492
493 /* contention window */
Daniel Halperin8fddddf2011-05-10 19:00:45 -0700494 tx_time_single += (t_slot * cw) >> 1;
495 cw = min((cw << 1) | 1, mp->cw_max);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200496
497 tx_time += tx_time_single;
498 tx_time_cts += tx_time_single + mi->sp_ack_dur;
499 tx_time_rtscts += tx_time_single + 2 * mi->sp_ack_dur;
500 if ((tx_time_cts < mp->segment_size) &&
501 (mr->retry_count_cts < mp->max_retry))
502 mr->retry_count_cts++;
503 if ((tx_time_rtscts < mp->segment_size) &&
504 (mr->retry_count_rtscts < mp->max_retry))
505 mr->retry_count_rtscts++;
506 } while ((tx_time < mp->segment_size) &&
507 (++mr->retry_count < mp->max_retry));
508 mr->adjusted_retry_count = mr->retry_count;
Felix Fietkau991fec02013-04-16 13:38:43 +0200509 if (!(sband->bitrates[i].flags & IEEE80211_RATE_ERP_G))
510 mr->retry_count_cts = mr->retry_count;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200511 }
512
513 for (i = n; i < sband->n_bitrates; i++) {
514 struct minstrel_rate *mr = &mi->r[i];
515 mr->rix = -1;
516 }
517
518 mi->n_rates = n;
519 mi->stats_update = jiffies;
520
521 init_sample_table(mi);
Felix Fietkau06d961a2013-04-22 16:14:43 +0200522 minstrel_update_rates(mp, mi);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200523}
524
525static void *
526minstrel_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
527{
528 struct ieee80211_supported_band *sband;
529 struct minstrel_sta_info *mi;
530 struct minstrel_priv *mp = priv;
531 struct ieee80211_hw *hw = mp->hw;
532 int max_rates = 0;
533 int i;
534
535 mi = kzalloc(sizeof(struct minstrel_sta_info), gfp);
536 if (!mi)
537 return NULL;
538
539 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
Jiri Slaby8e532172009-05-04 18:04:55 +0200540 sband = hw->wiphy->bands[i];
John W. Linville621ad7c2009-05-05 15:18:26 -0400541 if (sband && sband->n_bitrates > max_rates)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200542 max_rates = sband->n_bitrates;
543 }
544
545 mi->r = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
546 if (!mi->r)
547 goto error;
548
549 mi->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
550 if (!mi->sample_table)
551 goto error1;
552
553 mi->stats_update = jiffies;
554 return mi;
555
556error1:
557 kfree(mi->r);
558error:
559 kfree(mi);
560 return NULL;
561}
562
563static void
564minstrel_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
565{
566 struct minstrel_sta_info *mi = priv_sta;
567
568 kfree(mi->sample_table);
569 kfree(mi->r);
570 kfree(mi);
571}
572
Felix Fietkaua0497f92013-02-13 10:51:08 +0100573static void
574minstrel_init_cck_rates(struct minstrel_priv *mp)
575{
576 static const int bitrates[4] = { 10, 20, 55, 110 };
577 struct ieee80211_supported_band *sband;
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200578 u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
Felix Fietkaua0497f92013-02-13 10:51:08 +0100579 int i, j;
580
581 sband = mp->hw->wiphy->bands[IEEE80211_BAND_2GHZ];
582 if (!sband)
583 return;
584
585 for (i = 0, j = 0; i < sband->n_bitrates; i++) {
586 struct ieee80211_rate *rate = &sband->bitrates[i];
587
588 if (rate->flags & IEEE80211_RATE_ERP_G)
589 continue;
590
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200591 if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
592 continue;
593
Felix Fietkaua0497f92013-02-13 10:51:08 +0100594 for (j = 0; j < ARRAY_SIZE(bitrates); j++) {
595 if (rate->bitrate != bitrates[j])
596 continue;
597
598 mp->cck_rates[j] = i;
599 break;
600 }
601 }
602}
603
Felix Fietkaucccf1292008-10-05 18:07:45 +0200604static void *
605minstrel_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
606{
607 struct minstrel_priv *mp;
608
609 mp = kzalloc(sizeof(struct minstrel_priv), GFP_ATOMIC);
610 if (!mp)
611 return NULL;
612
613 /* contention window settings
614 * Just an approximation. Using the per-queue values would complicate
615 * the calculations and is probably unnecessary */
616 mp->cw_min = 15;
617 mp->cw_max = 1023;
618
619 /* number of packets (in %) to use for sampling other rates
620 * sample less often for non-mrr packets, because the overhead
621 * is much higher than with mrr */
622 mp->lookaround_rate = 5;
623 mp->lookaround_rate_mrr = 10;
624
Felix Fietkaucccf1292008-10-05 18:07:45 +0200625 /* maximum time that the hw is allowed to stay in one MRR segment */
626 mp->segment_size = 6000;
627
Johannes Berge6a98542008-10-21 12:40:02 +0200628 if (hw->max_rate_tries > 0)
629 mp->max_retry = hw->max_rate_tries;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200630 else
631 /* safe default, does not necessarily have to match hw properties */
632 mp->max_retry = 7;
633
Johannes Berge6a98542008-10-21 12:40:02 +0200634 if (hw->max_rates >= 4)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200635 mp->has_mrr = true;
636
637 mp->hw = hw;
638 mp->update_interval = 100;
639
Zefir Kurtisi24f75802011-05-20 20:29:17 +0200640#ifdef CONFIG_MAC80211_DEBUGFS
641 mp->fixed_rate_idx = (u32) -1;
642 mp->dbg_fixed_rate = debugfs_create_u32("fixed_rate_idx",
643 S_IRUGO | S_IWUGO, debugfsdir, &mp->fixed_rate_idx);
644#endif
645
Felix Fietkaua0497f92013-02-13 10:51:08 +0100646 minstrel_init_cck_rates(mp);
647
Felix Fietkaucccf1292008-10-05 18:07:45 +0200648 return mp;
649}
650
651static void
652minstrel_free(void *priv)
653{
Zefir Kurtisi24f75802011-05-20 20:29:17 +0200654#ifdef CONFIG_MAC80211_DEBUGFS
655 debugfs_remove(((struct minstrel_priv *)priv)->dbg_fixed_rate);
656#endif
Felix Fietkaucccf1292008-10-05 18:07:45 +0200657 kfree(priv);
658}
659
Felix Fietkaueae44752010-03-01 22:21:40 +0100660struct rate_control_ops mac80211_minstrel = {
Felix Fietkaucccf1292008-10-05 18:07:45 +0200661 .name = "minstrel",
662 .tx_status = minstrel_tx_status,
663 .get_rate = minstrel_get_rate,
664 .rate_init = minstrel_rate_init,
Felix Fietkaucccf1292008-10-05 18:07:45 +0200665 .alloc = minstrel_alloc,
666 .free = minstrel_free,
667 .alloc_sta = minstrel_alloc_sta,
668 .free_sta = minstrel_free_sta,
669#ifdef CONFIG_MAC80211_DEBUGFS
670 .add_sta_debugfs = minstrel_add_sta_debugfs,
671 .remove_sta_debugfs = minstrel_remove_sta_debugfs,
672#endif
673};
674
675int __init
676rc80211_minstrel_init(void)
677{
678 return ieee80211_rate_control_register(&mac80211_minstrel);
679}
680
681void
682rc80211_minstrel_exit(void)
683{
684 ieee80211_rate_control_unregister(&mac80211_minstrel);
685}
686