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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
Thomas Huehnca12c0c2014-09-09 23:22:13 +020078 while (j > 0 && mi->r[i].stats.cur_tp > mi->r[tp_list[j - 1]].stats.cur_tp)
Thomas Huehn2ff2b692013-03-04 23:30:07 +010079 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;
Thomas Huehnca12c0c2014-09-09 23:22:13 +020095 ratetbl->rate[offset].count_rts = r->stats.retry_count_rtscts;
Felix Fietkau06d961a2013-04-22 16:14:43 +020096}
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
Thomas Huehnf62838b2015-03-24 21:09:38 +0100130/*
131* Recalculate success probabilities and counters for a given rate using EWMA
132*/
133void
134minstrel_calc_rate_stats(struct minstrel_rate_stats *mrs)
135{
136 if (unlikely(mrs->attempts > 0)) {
137 mrs->sample_skipped = 0;
138 mrs->cur_prob = MINSTREL_FRAC(mrs->success, mrs->attempts);
139 if (unlikely(!mrs->att_hist))
140 mrs->probability = mrs->cur_prob;
141 else
142 mrs->probability = minstrel_ewma(mrs->probability,
143 mrs->cur_prob, EWMA_LEVEL);
144 mrs->att_hist += mrs->attempts;
145 mrs->succ_hist += mrs->success;
146 } else {
147 mrs->sample_skipped++;
148 }
149
150 mrs->last_success = mrs->success;
151 mrs->last_attempts = mrs->attempts;
152 mrs->success = 0;
153 mrs->attempts = 0;
154}
155
Felix Fietkau06d961a2013-04-22 16:14:43 +0200156static void
Felix Fietkaucccf1292008-10-05 18:07:45 +0200157minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
158{
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100159 u8 tmp_tp_rate[MAX_THR_RATES];
160 u8 tmp_prob_rate = 0;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200161 u32 usecs;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200162 int i;
163
Weilong Chenf359d3f2013-12-18 15:44:16 +0800164 for (i = 0; i < MAX_THR_RATES; i++)
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100165 tmp_tp_rate[i] = 0;
166
Felix Fietkaucccf1292008-10-05 18:07:45 +0200167 for (i = 0; i < mi->n_rates; i++) {
168 struct minstrel_rate *mr = &mi->r[i];
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200169 struct minstrel_rate_stats *mrs = &mi->r[i].stats;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200170
171 usecs = mr->perfect_tx_time;
172 if (!usecs)
173 usecs = 1000000;
174
Thomas Huehnf62838b2015-03-24 21:09:38 +0100175 /* Update success probabilities per rate */
176 minstrel_calc_rate_stats(mrs);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200177
Thomas Huehndb8c5ee2013-03-04 23:30:06 +0100178 /* Update throughput per rate, reset thr. below 10% success */
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200179 if (mrs->probability < MINSTREL_FRAC(10, 100))
180 mrs->cur_tp = 0;
Thomas Huehndb8c5ee2013-03-04 23:30:06 +0100181 else
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200182 mrs->cur_tp = mrs->probability * (1000000 / usecs);
Thomas Huehndb8c5ee2013-03-04 23:30:06 +0100183
Felix Fietkaucccf1292008-10-05 18:07:45 +0200184 /* Sample less often below the 10% chance of success.
185 * Sample less often above the 95% chance of success. */
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200186 if (mrs->probability > MINSTREL_FRAC(95, 100) ||
187 mrs->probability < MINSTREL_FRAC(10, 100)) {
188 mr->adjusted_retry_count = mrs->retry_count >> 1;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200189 if (mr->adjusted_retry_count > 2)
190 mr->adjusted_retry_count = 2;
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200191 mr->sample_limit = 4;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200192 } else {
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200193 mr->sample_limit = -1;
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200194 mr->adjusted_retry_count = mrs->retry_count;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200195 }
196 if (!mr->adjusted_retry_count)
197 mr->adjusted_retry_count = 2;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200198
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100199 minstrel_sort_best_tp_rates(mi, i, tmp_tp_rate);
200
201 /* To determine the most robust rate (max_prob_rate) used at
202 * 3rd mmr stage we distinct between two cases:
203 * (1) if any success probabilitiy >= 95%, out of those rates
204 * choose the maximum throughput rate as max_prob_rate
205 * (2) if all success probabilities < 95%, the rate with
Stephen Hemmingerd070f912014-10-29 22:55:58 -0700206 * highest success probability is chosen as max_prob_rate */
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200207 if (mrs->probability >= MINSTREL_FRAC(95, 100)) {
208 if (mrs->cur_tp >= mi->r[tmp_prob_rate].stats.cur_tp)
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100209 tmp_prob_rate = i;
210 } else {
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200211 if (mrs->probability >= mi->r[tmp_prob_rate].stats.probability)
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100212 tmp_prob_rate = i;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200213 }
214 }
215
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100216 /* Assign the new rate set */
217 memcpy(mi->max_tp_rate, tmp_tp_rate, sizeof(mi->max_tp_rate));
218 mi->max_prob_rate = tmp_prob_rate;
Thomas Huehn8f157612013-03-04 23:30:03 +0100219
Lorenzo Bianconi45966ae2013-08-27 16:59:46 +0200220#ifdef CONFIG_MAC80211_DEBUGFS
221 /* use fixed index if set */
222 if (mp->fixed_rate_idx != -1) {
223 mi->max_tp_rate[0] = mp->fixed_rate_idx;
224 mi->max_tp_rate[1] = mp->fixed_rate_idx;
225 mi->max_prob_rate = mp->fixed_rate_idx;
226 }
227#endif
228
Thomas Huehn8f157612013-03-04 23:30:03 +0100229 /* Reset update timer */
230 mi->stats_update = jiffies;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200231
232 minstrel_update_rates(mp, mi);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200233}
234
235static void
236minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband,
Weilong Chenf359d3f2013-12-18 15:44:16 +0800237 struct ieee80211_sta *sta, void *priv_sta,
Felix Fietkaufb7acfb2014-11-19 20:08:09 +0100238 struct ieee80211_tx_info *info)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200239{
Johannes Berg8acbcdd2012-11-15 18:27:56 +0100240 struct minstrel_priv *mp = priv;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200241 struct minstrel_sta_info *mi = priv_sta;
Johannes Berge6a98542008-10-21 12:40:02 +0200242 struct ieee80211_tx_rate *ar = info->status.rates;
243 int i, ndx;
244 int success;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200245
Johannes Berge6a98542008-10-21 12:40:02 +0200246 success = !!(info->flags & IEEE80211_TX_STAT_ACK);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200247
Johannes Berge6a98542008-10-21 12:40:02 +0200248 for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
249 if (ar[i].idx < 0)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200250 break;
251
Johannes Berge6a98542008-10-21 12:40:02 +0200252 ndx = rix_to_ndx(mi, ar[i].idx);
Luciano Coelho3938b452009-07-03 08:25:08 +0300253 if (ndx < 0)
254 continue;
255
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200256 mi->r[ndx].stats.attempts += ar[i].count;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200257
Javier Cardonabfc32e62009-08-17 17:15:55 -0700258 if ((i != IEEE80211_TX_MAX_RATES - 1) && (ar[i + 1].idx < 0))
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200259 mi->r[ndx].stats.success += success;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200260 }
261
262 if ((info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) && (i >= 0))
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200263 mi->sample_packets++;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200264
265 if (mi->sample_deferred > 0)
266 mi->sample_deferred--;
Johannes Berg8acbcdd2012-11-15 18:27:56 +0100267
268 if (time_after(jiffies, mi->stats_update +
269 (mp->update_interval * HZ) / 1000))
270 minstrel_update_stats(mp, mi);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200271}
272
273
274static inline unsigned int
275minstrel_get_retry_count(struct minstrel_rate *mr,
Weilong Chenf359d3f2013-12-18 15:44:16 +0800276 struct ieee80211_tx_info *info)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200277{
Felix Fietkau8d819a92014-12-17 13:38:34 +0100278 u8 retry = mr->adjusted_retry_count;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200279
Felix Fietkau991fec02013-04-16 13:38:43 +0200280 if (info->control.use_rts)
Felix Fietkau8d819a92014-12-17 13:38:34 +0100281 retry = max_t(u8, 2, min(mr->stats.retry_count_rtscts, retry));
Felix Fietkau991fec02013-04-16 13:38:43 +0200282 else if (info->control.use_cts_prot)
Felix Fietkau8d819a92014-12-17 13:38:34 +0100283 retry = max_t(u8, 2, min(mr->retry_count_cts, retry));
Felix Fietkaucccf1292008-10-05 18:07:45 +0200284 return retry;
285}
286
287
288static int
289minstrel_get_next_sample(struct minstrel_sta_info *mi)
290{
291 unsigned int sample_ndx;
Thomas Huehn8f157612013-03-04 23:30:03 +0100292 sample_ndx = SAMPLE_TBL(mi, mi->sample_row, mi->sample_column);
293 mi->sample_row++;
Thomas Huehnf744bf82013-03-04 23:30:05 +0100294 if ((int) mi->sample_row >= mi->n_rates) {
Thomas Huehn8f157612013-03-04 23:30:03 +0100295 mi->sample_row = 0;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200296 mi->sample_column++;
297 if (mi->sample_column >= SAMPLE_COLUMNS)
298 mi->sample_column = 0;
299 }
300 return sample_ndx;
301}
302
Johannes Berg2df78162008-10-28 16:49:41 +0100303static void
Johannes Berge6a98542008-10-21 12:40:02 +0200304minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
305 void *priv_sta, struct ieee80211_tx_rate_control *txrc)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200306{
Johannes Berge6a98542008-10-21 12:40:02 +0200307 struct sk_buff *skb = txrc->skb;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200308 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
309 struct minstrel_sta_info *mi = priv_sta;
310 struct minstrel_priv *mp = priv;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200311 struct ieee80211_tx_rate *rate = &info->control.rates[0];
312 struct minstrel_rate *msr, *mr;
313 unsigned int ndx;
Thomas Huehn8f157612013-03-04 23:30:03 +0100314 bool mrr_capable;
Felix Fietkau5c9fc932013-07-15 14:35:06 +0200315 bool prev_sample;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200316 int delta;
Thomas Huehn8f157612013-03-04 23:30:03 +0100317 int sampling_ratio;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200318
Thomas Huehn8f157612013-03-04 23:30:03 +0100319 /* management/no-ack frames do not use rate control */
Luis R. Rodriguez4c6d4f52009-07-16 10:05:41 -0700320 if (rate_control_send_low(sta, priv_sta, txrc))
Felix Fietkaucccf1292008-10-05 18:07:45 +0200321 return;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200322
Thomas Huehn8f157612013-03-04 23:30:03 +0100323 /* check multi-rate-retry capabilities & adjust lookaround_rate */
324 mrr_capable = mp->has_mrr &&
325 !txrc->rts &&
326 !txrc->bss_conf->use_cts_prot;
327 if (mrr_capable)
328 sampling_ratio = mp->lookaround_rate_mrr;
329 else
330 sampling_ratio = mp->lookaround_rate;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200331
Thomas Huehn8f157612013-03-04 23:30:03 +0100332 /* increase sum packet counter */
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200333 mi->total_packets++;
Thomas Huehn8f157612013-03-04 23:30:03 +0100334
Lorenzo Bianconi45966ae2013-08-27 16:59:46 +0200335#ifdef CONFIG_MAC80211_DEBUGFS
336 if (mp->fixed_rate_idx != -1)
337 return;
338#endif
339
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200340 delta = (mi->total_packets * sampling_ratio / 100) -
341 (mi->sample_packets + mi->sample_deferred / 2);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200342
Felix Fietkau06d961a2013-04-22 16:14:43 +0200343 /* delta < 0: no sampling required */
Felix Fietkau5c9fc932013-07-15 14:35:06 +0200344 prev_sample = mi->prev_sample;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200345 mi->prev_sample = false;
346 if (delta < 0 || (!mrr_capable && prev_sample))
347 return;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200348
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200349 if (mi->total_packets >= 10000) {
Felix Fietkau06d961a2013-04-22 16:14:43 +0200350 mi->sample_deferred = 0;
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200351 mi->sample_packets = 0;
352 mi->total_packets = 0;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200353 } else if (delta > mi->n_rates * 2) {
354 /* With multi-rate retry, not every planned sample
355 * attempt actually gets used, due to the way the retry
356 * chain is set up - [max_tp,sample,prob,lowest] for
357 * sample_rate < max_tp.
358 *
359 * If there's too much sampling backlog and the link
360 * starts getting worse, minstrel would start bursting
361 * out lots of sampling frames, which would result
362 * in a large throughput loss. */
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200363 mi->sample_packets += (delta - mi->n_rates * 2);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200364 }
Felix Fietkau06d961a2013-04-22 16:14:43 +0200365
366 /* get next random rate sample */
367 ndx = minstrel_get_next_sample(mi);
368 msr = &mi->r[ndx];
369 mr = &mi->r[mi->max_tp_rate[0]];
370
371 /* Decide if direct ( 1st mrr stage) or indirect (2nd mrr stage)
372 * rate sampling method should be used.
373 * Respect such rates that are not sampled for 20 interations.
374 */
375 if (mrr_capable &&
376 msr->perfect_tx_time > mr->perfect_tx_time &&
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200377 msr->stats.sample_skipped < 20) {
Felix Fietkau06d961a2013-04-22 16:14:43 +0200378 /* Only use IEEE80211_TX_CTL_RATE_CTRL_PROBE to mark
379 * packets that have the sampling rate deferred to the
380 * second MRR stage. Increase the sample counter only
381 * if the deferred sample rate was actually used.
382 * Use the sample_deferred counter to make sure that
383 * the sampling is not done in large bursts */
384 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
385 rate++;
386 mi->sample_deferred++;
387 } else {
Jiri Slaby17dce152015-02-19 12:57:40 +0100388 if (!msr->sample_limit)
Felix Fietkau06d961a2013-04-22 16:14:43 +0200389 return;
390
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200391 mi->sample_packets++;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200392 if (msr->sample_limit > 0)
393 msr->sample_limit--;
394 }
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200395
396 /* If we're not using MRR and the sampling rate already
397 * has a probability of >95%, we shouldn't be attempting
398 * to use it, as this only wastes precious airtime */
Felix Fietkau06d961a2013-04-22 16:14:43 +0200399 if (!mrr_capable &&
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200400 (mi->r[ndx].stats.probability > MINSTREL_FRAC(95, 100)))
Felix Fietkaucccf1292008-10-05 18:07:45 +0200401 return;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200402
Felix Fietkau06d961a2013-04-22 16:14:43 +0200403 mi->prev_sample = true;
Thomas Huehn8f157612013-03-04 23:30:03 +0100404
Felix Fietkau06d961a2013-04-22 16:14:43 +0200405 rate->idx = mi->r[ndx].rix;
406 rate->count = minstrel_get_retry_count(&mi->r[ndx], info);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200407}
408
409
410static void
Michal Kazior4ee73f32012-04-11 08:47:56 +0200411calc_rate_durations(enum ieee80211_band band,
412 struct minstrel_rate *d,
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200413 struct ieee80211_rate *rate,
414 struct cfg80211_chan_def *chandef)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200415{
416 int erp = !!(rate->flags & IEEE80211_RATE_ERP_G);
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200417 int shift = ieee80211_chandef_get_shift(chandef);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200418
Michal Kazior4ee73f32012-04-11 08:47:56 +0200419 d->perfect_tx_time = ieee80211_frame_duration(band, 1200,
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200420 DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
421 shift);
Michal Kazior4ee73f32012-04-11 08:47:56 +0200422 d->ack_time = ieee80211_frame_duration(band, 10,
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200423 DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
424 shift);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200425}
426
427static void
428init_sample_table(struct minstrel_sta_info *mi)
429{
430 unsigned int i, col, new_idx;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200431 u8 rnd[8];
432
433 mi->sample_column = 0;
Thomas Huehn8f157612013-03-04 23:30:03 +0100434 mi->sample_row = 0;
Thomas Huehnf744bf82013-03-04 23:30:05 +0100435 memset(mi->sample_table, 0xff, SAMPLE_COLUMNS * mi->n_rates);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200436
437 for (col = 0; col < SAMPLE_COLUMNS; col++) {
Karl Beldanf7d8ad82013-11-13 10:54:19 +0100438 prandom_bytes(rnd, sizeof(rnd));
Thomas Huehnf744bf82013-03-04 23:30:05 +0100439 for (i = 0; i < mi->n_rates; i++) {
Thomas Huehnf744bf82013-03-04 23:30:05 +0100440 new_idx = (i + rnd[i & 7]) % mi->n_rates;
Thomas Huehnf744bf82013-03-04 23:30:05 +0100441 while (SAMPLE_TBL(mi, new_idx, col) != 0xff)
442 new_idx = (new_idx + 1) % mi->n_rates;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200443
Thomas Huehnf744bf82013-03-04 23:30:05 +0100444 SAMPLE_TBL(mi, new_idx, col) = i;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200445 }
446 }
447}
448
449static void
450minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
Simon Wunderlich3de805c2013-07-08 16:55:50 +0200451 struct cfg80211_chan_def *chandef,
452 struct ieee80211_sta *sta, void *priv_sta)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200453{
454 struct minstrel_sta_info *mi = priv_sta;
455 struct minstrel_priv *mp = priv;
Christian Lamparterd57854b2008-12-22 15:35:31 +0100456 struct ieee80211_rate *ctl_rate;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200457 unsigned int i, n = 0;
458 unsigned int t_slot = 9; /* FIXME: get real slot time */
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200459 u32 rate_flags;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200460
Felix Fietkau06d961a2013-04-22 16:14:43 +0200461 mi->sta = sta;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200462 mi->lowest_rix = rate_lowest_index(sband, sta);
Christian Lamparterd57854b2008-12-22 15:35:31 +0100463 ctl_rate = &sband->bitrates[mi->lowest_rix];
Michal Kazior4ee73f32012-04-11 08:47:56 +0200464 mi->sp_ack_dur = ieee80211_frame_duration(sband->band, 10,
465 ctl_rate->bitrate,
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200466 !!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1,
467 ieee80211_chandef_get_shift(chandef));
Felix Fietkaucccf1292008-10-05 18:07:45 +0200468
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200469 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
Felix Fietkau06d961a2013-04-22 16:14:43 +0200470 memset(mi->max_tp_rate, 0, sizeof(mi->max_tp_rate));
471 mi->max_prob_rate = 0;
472
Felix Fietkaucccf1292008-10-05 18:07:45 +0200473 for (i = 0; i < sband->n_bitrates; i++) {
474 struct minstrel_rate *mr = &mi->r[n];
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200475 struct minstrel_rate_stats *mrs = &mi->r[n].stats;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200476 unsigned int tx_time = 0, tx_time_cts = 0, tx_time_rtscts = 0;
477 unsigned int tx_time_single;
478 unsigned int cw = mp->cw_min;
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200479 int shift;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200480
481 if (!rate_supported(sta, sband->band, i))
482 continue;
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200483 if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
484 continue;
485
Felix Fietkaucccf1292008-10-05 18:07:45 +0200486 n++;
487 memset(mr, 0, sizeof(*mr));
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200488 memset(mrs, 0, sizeof(*mrs));
Felix Fietkaucccf1292008-10-05 18:07:45 +0200489
490 mr->rix = i;
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200491 shift = ieee80211_chandef_get_shift(chandef);
492 mr->bitrate = DIV_ROUND_UP(sband->bitrates[i].bitrate,
493 (1 << shift) * 5);
494 calc_rate_durations(sband->band, mr, &sband->bitrates[i],
495 chandef);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200496
497 /* calculate maximum number of retransmissions before
498 * fallback (based on maximum segment size) */
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200499 mr->sample_limit = -1;
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200500 mrs->retry_count = 1;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200501 mr->retry_count_cts = 1;
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200502 mrs->retry_count_rtscts = 1;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200503 tx_time = mr->perfect_tx_time + mi->sp_ack_dur;
504 do {
505 /* add one retransmission */
506 tx_time_single = mr->ack_time + mr->perfect_tx_time;
507
508 /* contention window */
Daniel Halperin8fddddf2011-05-10 19:00:45 -0700509 tx_time_single += (t_slot * cw) >> 1;
510 cw = min((cw << 1) | 1, mp->cw_max);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200511
512 tx_time += tx_time_single;
513 tx_time_cts += tx_time_single + mi->sp_ack_dur;
514 tx_time_rtscts += tx_time_single + 2 * mi->sp_ack_dur;
515 if ((tx_time_cts < mp->segment_size) &&
516 (mr->retry_count_cts < mp->max_retry))
517 mr->retry_count_cts++;
518 if ((tx_time_rtscts < mp->segment_size) &&
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200519 (mrs->retry_count_rtscts < mp->max_retry))
520 mrs->retry_count_rtscts++;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200521 } while ((tx_time < mp->segment_size) &&
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200522 (++mr->stats.retry_count < mp->max_retry));
523 mr->adjusted_retry_count = mrs->retry_count;
Felix Fietkau991fec02013-04-16 13:38:43 +0200524 if (!(sband->bitrates[i].flags & IEEE80211_RATE_ERP_G))
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200525 mr->retry_count_cts = mrs->retry_count;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200526 }
527
528 for (i = n; i < sband->n_bitrates; i++) {
529 struct minstrel_rate *mr = &mi->r[i];
530 mr->rix = -1;
531 }
532
533 mi->n_rates = n;
534 mi->stats_update = jiffies;
535
536 init_sample_table(mi);
Felix Fietkau06d961a2013-04-22 16:14:43 +0200537 minstrel_update_rates(mp, mi);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200538}
539
540static void *
541minstrel_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
542{
543 struct ieee80211_supported_band *sband;
544 struct minstrel_sta_info *mi;
545 struct minstrel_priv *mp = priv;
546 struct ieee80211_hw *hw = mp->hw;
547 int max_rates = 0;
548 int i;
549
550 mi = kzalloc(sizeof(struct minstrel_sta_info), gfp);
551 if (!mi)
552 return NULL;
553
554 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
Jiri Slaby8e532172009-05-04 18:04:55 +0200555 sband = hw->wiphy->bands[i];
John W. Linville621ad7c2009-05-05 15:18:26 -0400556 if (sband && sband->n_bitrates > max_rates)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200557 max_rates = sband->n_bitrates;
558 }
559
560 mi->r = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
561 if (!mi->r)
562 goto error;
563
564 mi->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
565 if (!mi->sample_table)
566 goto error1;
567
568 mi->stats_update = jiffies;
569 return mi;
570
571error1:
572 kfree(mi->r);
573error:
574 kfree(mi);
575 return NULL;
576}
577
578static void
579minstrel_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
580{
581 struct minstrel_sta_info *mi = priv_sta;
582
583 kfree(mi->sample_table);
584 kfree(mi->r);
585 kfree(mi);
586}
587
Felix Fietkaua0497f92013-02-13 10:51:08 +0100588static void
589minstrel_init_cck_rates(struct minstrel_priv *mp)
590{
591 static const int bitrates[4] = { 10, 20, 55, 110 };
592 struct ieee80211_supported_band *sband;
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200593 u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
Felix Fietkaua0497f92013-02-13 10:51:08 +0100594 int i, j;
595
596 sband = mp->hw->wiphy->bands[IEEE80211_BAND_2GHZ];
597 if (!sband)
598 return;
599
600 for (i = 0, j = 0; i < sband->n_bitrates; i++) {
601 struct ieee80211_rate *rate = &sband->bitrates[i];
602
603 if (rate->flags & IEEE80211_RATE_ERP_G)
604 continue;
605
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200606 if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
607 continue;
608
Felix Fietkaua0497f92013-02-13 10:51:08 +0100609 for (j = 0; j < ARRAY_SIZE(bitrates); j++) {
610 if (rate->bitrate != bitrates[j])
611 continue;
612
613 mp->cck_rates[j] = i;
614 break;
615 }
616 }
617}
618
Felix Fietkaucccf1292008-10-05 18:07:45 +0200619static void *
620minstrel_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
621{
622 struct minstrel_priv *mp;
623
624 mp = kzalloc(sizeof(struct minstrel_priv), GFP_ATOMIC);
625 if (!mp)
626 return NULL;
627
628 /* contention window settings
629 * Just an approximation. Using the per-queue values would complicate
630 * the calculations and is probably unnecessary */
631 mp->cw_min = 15;
632 mp->cw_max = 1023;
633
634 /* number of packets (in %) to use for sampling other rates
635 * sample less often for non-mrr packets, because the overhead
636 * is much higher than with mrr */
637 mp->lookaround_rate = 5;
638 mp->lookaround_rate_mrr = 10;
639
Felix Fietkaucccf1292008-10-05 18:07:45 +0200640 /* maximum time that the hw is allowed to stay in one MRR segment */
641 mp->segment_size = 6000;
642
Johannes Berge6a98542008-10-21 12:40:02 +0200643 if (hw->max_rate_tries > 0)
644 mp->max_retry = hw->max_rate_tries;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200645 else
646 /* safe default, does not necessarily have to match hw properties */
647 mp->max_retry = 7;
648
Johannes Berge6a98542008-10-21 12:40:02 +0200649 if (hw->max_rates >= 4)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200650 mp->has_mrr = true;
651
652 mp->hw = hw;
653 mp->update_interval = 100;
654
Zefir Kurtisi24f75802011-05-20 20:29:17 +0200655#ifdef CONFIG_MAC80211_DEBUGFS
656 mp->fixed_rate_idx = (u32) -1;
657 mp->dbg_fixed_rate = debugfs_create_u32("fixed_rate_idx",
658 S_IRUGO | S_IWUGO, debugfsdir, &mp->fixed_rate_idx);
659#endif
660
Felix Fietkaua0497f92013-02-13 10:51:08 +0100661 minstrel_init_cck_rates(mp);
662
Felix Fietkaucccf1292008-10-05 18:07:45 +0200663 return mp;
664}
665
666static void
667minstrel_free(void *priv)
668{
Zefir Kurtisi24f75802011-05-20 20:29:17 +0200669#ifdef CONFIG_MAC80211_DEBUGFS
670 debugfs_remove(((struct minstrel_priv *)priv)->dbg_fixed_rate);
671#endif
Felix Fietkaucccf1292008-10-05 18:07:45 +0200672 kfree(priv);
673}
674
Antonio Quartullicca674d2014-05-19 21:53:20 +0200675static u32 minstrel_get_expected_throughput(void *priv_sta)
676{
677 struct minstrel_sta_info *mi = priv_sta;
678 int idx = mi->max_tp_rate[0];
679
680 /* convert pkt per sec in kbps (1200 is the average pkt size used for
681 * computing cur_tp
682 */
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200683 return MINSTREL_TRUNC(mi->r[idx].stats.cur_tp) * 1200 * 8 / 1024;
Antonio Quartullicca674d2014-05-19 21:53:20 +0200684}
685
Johannes Berg631ad702014-01-20 23:29:34 +0100686const struct rate_control_ops mac80211_minstrel = {
Felix Fietkaucccf1292008-10-05 18:07:45 +0200687 .name = "minstrel",
Felix Fietkaufb7acfb2014-11-19 20:08:09 +0100688 .tx_status_noskb = minstrel_tx_status,
Felix Fietkaucccf1292008-10-05 18:07:45 +0200689 .get_rate = minstrel_get_rate,
690 .rate_init = minstrel_rate_init,
Felix Fietkaucccf1292008-10-05 18:07:45 +0200691 .alloc = minstrel_alloc,
692 .free = minstrel_free,
693 .alloc_sta = minstrel_alloc_sta,
694 .free_sta = minstrel_free_sta,
695#ifdef CONFIG_MAC80211_DEBUGFS
696 .add_sta_debugfs = minstrel_add_sta_debugfs,
697 .remove_sta_debugfs = minstrel_remove_sta_debugfs,
698#endif
Antonio Quartullicca674d2014-05-19 21:53:20 +0200699 .get_expected_throughput = minstrel_get_expected_throughput,
Felix Fietkaucccf1292008-10-05 18:07:45 +0200700};
701
702int __init
703rc80211_minstrel_init(void)
704{
705 return ieee80211_rate_control_register(&mac80211_minstrel);
706}
707
708void
709rc80211_minstrel_exit(void)
710{
711 ieee80211_rate_control_unregister(&mac80211_minstrel);
712}
713