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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 Huehn6a27b2c2015-03-24 21:09:40 +010072/* return current EMWA throughput */
Thomas Huehn50e55a82015-03-24 21:09:41 +010073int minstrel_get_tp_avg(struct minstrel_rate *mr, int prob_ewma)
Thomas Huehn6a27b2c2015-03-24 21:09:40 +010074{
75 int usecs;
76
77 usecs = mr->perfect_tx_time;
78 if (!usecs)
79 usecs = 1000000;
80
81 /* reset thr. below 10% success */
82 if (mr->stats.prob_ewma < MINSTREL_FRAC(10, 100))
83 return 0;
Thomas Huehn50e55a82015-03-24 21:09:41 +010084
85 if (prob_ewma > MINSTREL_FRAC(90, 100))
86 return MINSTREL_TRUNC(100000 * (MINSTREL_FRAC(90, 100) / usecs));
Thomas Huehn6a27b2c2015-03-24 21:09:40 +010087 else
Thomas Huehn50e55a82015-03-24 21:09:41 +010088 return MINSTREL_TRUNC(100000 * (prob_ewma / usecs));
Thomas Huehn6a27b2c2015-03-24 21:09:40 +010089}
90
Thomas Huehn2ff2b692013-03-04 23:30:07 +010091/* find & sort topmost throughput rates */
92static inline void
93minstrel_sort_best_tp_rates(struct minstrel_sta_info *mi, int i, u8 *tp_list)
94{
95 int j = MAX_THR_RATES;
Thomas Huehn50e55a82015-03-24 21:09:41 +010096 struct minstrel_rate_stats *tmp_mrs = &mi->r[j - 1].stats;
97 struct minstrel_rate_stats *cur_mrs = &mi->r[i].stats;
Thomas Huehn2ff2b692013-03-04 23:30:07 +010098
Thomas Huehn50e55a82015-03-24 21:09:41 +010099 while (j > 0 && (minstrel_get_tp_avg(&mi->r[i], cur_mrs->prob_ewma) >
100 minstrel_get_tp_avg(&mi->r[tp_list[j - 1]], tmp_mrs->prob_ewma))) {
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100101 j--;
Thomas Huehn50e55a82015-03-24 21:09:41 +0100102 tmp_mrs = &mi->r[tp_list[j - 1]].stats;
103 }
Thomas Huehn6a27b2c2015-03-24 21:09:40 +0100104
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100105 if (j < MAX_THR_RATES - 1)
106 memmove(&tp_list[j + 1], &tp_list[j], MAX_THR_RATES - (j + 1));
107 if (j < MAX_THR_RATES)
108 tp_list[j] = i;
109}
110
Felix Fietkaucccf1292008-10-05 18:07:45 +0200111static void
Felix Fietkau06d961a2013-04-22 16:14:43 +0200112minstrel_set_rate(struct minstrel_sta_info *mi, struct ieee80211_sta_rates *ratetbl,
113 int offset, int idx)
114{
115 struct minstrel_rate *r = &mi->r[idx];
116
117 ratetbl->rate[offset].idx = r->rix;
118 ratetbl->rate[offset].count = r->adjusted_retry_count;
119 ratetbl->rate[offset].count_cts = r->retry_count_cts;
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200120 ratetbl->rate[offset].count_rts = r->stats.retry_count_rtscts;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200121}
122
123static void
124minstrel_update_rates(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
125{
126 struct ieee80211_sta_rates *ratetbl;
127 int i = 0;
128
129 ratetbl = kzalloc(sizeof(*ratetbl), GFP_ATOMIC);
130 if (!ratetbl)
131 return;
132
133 /* Start with max_tp_rate */
134 minstrel_set_rate(mi, ratetbl, i++, mi->max_tp_rate[0]);
135
136 if (mp->hw->max_rates >= 3) {
137 /* At least 3 tx rates supported, use max_tp_rate2 next */
138 minstrel_set_rate(mi, ratetbl, i++, mi->max_tp_rate[1]);
139 }
140
141 if (mp->hw->max_rates >= 2) {
142 /* At least 2 tx rates supported, use max_prob_rate next */
143 minstrel_set_rate(mi, ratetbl, i++, mi->max_prob_rate);
144 }
145
146 /* Use lowest rate last */
147 ratetbl->rate[i].idx = mi->lowest_rix;
148 ratetbl->rate[i].count = mp->max_retry;
149 ratetbl->rate[i].count_cts = mp->max_retry;
150 ratetbl->rate[i].count_rts = mp->max_retry;
151
152 rate_control_set_rates(mp->hw, mi->sta, ratetbl);
153}
154
Thomas Huehnf62838b2015-03-24 21:09:38 +0100155/*
Thomas Huehn5f919ab2015-03-24 21:09:43 +0100156* Recalculate statistics and counters of a given rate
Thomas Huehnf62838b2015-03-24 21:09:38 +0100157*/
158void
159minstrel_calc_rate_stats(struct minstrel_rate_stats *mrs)
160{
161 if (unlikely(mrs->attempts > 0)) {
162 mrs->sample_skipped = 0;
163 mrs->cur_prob = MINSTREL_FRAC(mrs->success, mrs->attempts);
Thomas Huehn5f919ab2015-03-24 21:09:43 +0100164 if (unlikely(!mrs->att_hist)) {
Thomas Huehn91340732015-03-24 21:09:39 +0100165 mrs->prob_ewma = mrs->cur_prob;
Thomas Huehn5f919ab2015-03-24 21:09:43 +0100166 } else {
167 /* update exponential weighted moving variance */
168 mrs->prob_ewmsd = minstrel_ewmsd(mrs->prob_ewmsd,
169 mrs->cur_prob,
170 mrs->prob_ewma,
171 EWMA_LEVEL);
172
173 /*update exponential weighted moving avarage */
Thomas Huehn91340732015-03-24 21:09:39 +0100174 mrs->prob_ewma = minstrel_ewma(mrs->prob_ewma,
Thomas Huehn5f919ab2015-03-24 21:09:43 +0100175 mrs->cur_prob,
176 EWMA_LEVEL);
177 }
Thomas Huehnf62838b2015-03-24 21:09:38 +0100178 mrs->att_hist += mrs->attempts;
179 mrs->succ_hist += mrs->success;
180 } else {
181 mrs->sample_skipped++;
182 }
183
184 mrs->last_success = mrs->success;
185 mrs->last_attempts = mrs->attempts;
186 mrs->success = 0;
187 mrs->attempts = 0;
188}
189
Felix Fietkau06d961a2013-04-22 16:14:43 +0200190static void
Felix Fietkaucccf1292008-10-05 18:07:45 +0200191minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
192{
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100193 u8 tmp_tp_rate[MAX_THR_RATES];
194 u8 tmp_prob_rate = 0;
Thomas Huehn6a27b2c2015-03-24 21:09:40 +0100195 int i, tmp_cur_tp, tmp_prob_tp;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200196
Weilong Chenf359d3f2013-12-18 15:44:16 +0800197 for (i = 0; i < MAX_THR_RATES; i++)
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100198 tmp_tp_rate[i] = 0;
199
Felix Fietkaucccf1292008-10-05 18:07:45 +0200200 for (i = 0; i < mi->n_rates; i++) {
201 struct minstrel_rate *mr = &mi->r[i];
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200202 struct minstrel_rate_stats *mrs = &mi->r[i].stats;
Thomas Huehn50e55a82015-03-24 21:09:41 +0100203 struct minstrel_rate_stats *tmp_mrs = &mi->r[tmp_prob_rate].stats;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200204
Thomas Huehn5f919ab2015-03-24 21:09:43 +0100205 /* Update statistics of success probability per rate */
Thomas Huehnf62838b2015-03-24 21:09:38 +0100206 minstrel_calc_rate_stats(mrs);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200207
208 /* Sample less often below the 10% chance of success.
209 * Sample less often above the 95% chance of success. */
Thomas Huehn91340732015-03-24 21:09:39 +0100210 if (mrs->prob_ewma > MINSTREL_FRAC(95, 100) ||
211 mrs->prob_ewma < MINSTREL_FRAC(10, 100)) {
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200212 mr->adjusted_retry_count = mrs->retry_count >> 1;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200213 if (mr->adjusted_retry_count > 2)
214 mr->adjusted_retry_count = 2;
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200215 mr->sample_limit = 4;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200216 } else {
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200217 mr->sample_limit = -1;
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200218 mr->adjusted_retry_count = mrs->retry_count;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200219 }
220 if (!mr->adjusted_retry_count)
221 mr->adjusted_retry_count = 2;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200222
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100223 minstrel_sort_best_tp_rates(mi, i, tmp_tp_rate);
224
225 /* To determine the most robust rate (max_prob_rate) used at
226 * 3rd mmr stage we distinct between two cases:
227 * (1) if any success probabilitiy >= 95%, out of those rates
228 * choose the maximum throughput rate as max_prob_rate
229 * (2) if all success probabilities < 95%, the rate with
Stephen Hemmingerd070f912014-10-29 22:55:58 -0700230 * highest success probability is chosen as max_prob_rate */
Thomas Huehn91340732015-03-24 21:09:39 +0100231 if (mrs->prob_ewma >= MINSTREL_FRAC(95, 100)) {
Thomas Huehn50e55a82015-03-24 21:09:41 +0100232 tmp_cur_tp = minstrel_get_tp_avg(mr, mrs->prob_ewma);
233 tmp_prob_tp = minstrel_get_tp_avg(&mi->r[tmp_prob_rate],
234 tmp_mrs->prob_ewma);
Thomas Huehn6a27b2c2015-03-24 21:09:40 +0100235 if (tmp_cur_tp >= tmp_prob_tp)
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100236 tmp_prob_rate = i;
237 } else {
Thomas Huehn50e55a82015-03-24 21:09:41 +0100238 if (mrs->prob_ewma >= tmp_mrs->prob_ewma)
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100239 tmp_prob_rate = i;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200240 }
241 }
242
Thomas Huehn2ff2b692013-03-04 23:30:07 +0100243 /* Assign the new rate set */
244 memcpy(mi->max_tp_rate, tmp_tp_rate, sizeof(mi->max_tp_rate));
245 mi->max_prob_rate = tmp_prob_rate;
Thomas Huehn8f157612013-03-04 23:30:03 +0100246
Lorenzo Bianconi45966ae2013-08-27 16:59:46 +0200247#ifdef CONFIG_MAC80211_DEBUGFS
248 /* use fixed index if set */
249 if (mp->fixed_rate_idx != -1) {
250 mi->max_tp_rate[0] = mp->fixed_rate_idx;
251 mi->max_tp_rate[1] = mp->fixed_rate_idx;
252 mi->max_prob_rate = mp->fixed_rate_idx;
253 }
254#endif
255
Thomas Huehn8f157612013-03-04 23:30:03 +0100256 /* Reset update timer */
Thomas Huehn91340732015-03-24 21:09:39 +0100257 mi->last_stats_update = jiffies;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200258
259 minstrel_update_rates(mp, mi);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200260}
261
262static void
263minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband,
Weilong Chenf359d3f2013-12-18 15:44:16 +0800264 struct ieee80211_sta *sta, void *priv_sta,
Felix Fietkaufb7acfb2014-11-19 20:08:09 +0100265 struct ieee80211_tx_info *info)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200266{
Johannes Berg8acbcdd2012-11-15 18:27:56 +0100267 struct minstrel_priv *mp = priv;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200268 struct minstrel_sta_info *mi = priv_sta;
Johannes Berge6a98542008-10-21 12:40:02 +0200269 struct ieee80211_tx_rate *ar = info->status.rates;
270 int i, ndx;
271 int success;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200272
Johannes Berge6a98542008-10-21 12:40:02 +0200273 success = !!(info->flags & IEEE80211_TX_STAT_ACK);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200274
Johannes Berge6a98542008-10-21 12:40:02 +0200275 for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
276 if (ar[i].idx < 0)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200277 break;
278
Johannes Berge6a98542008-10-21 12:40:02 +0200279 ndx = rix_to_ndx(mi, ar[i].idx);
Luciano Coelho3938b452009-07-03 08:25:08 +0300280 if (ndx < 0)
281 continue;
282
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200283 mi->r[ndx].stats.attempts += ar[i].count;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200284
Javier Cardonabfc32e62009-08-17 17:15:55 -0700285 if ((i != IEEE80211_TX_MAX_RATES - 1) && (ar[i + 1].idx < 0))
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200286 mi->r[ndx].stats.success += success;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200287 }
288
289 if ((info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) && (i >= 0))
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200290 mi->sample_packets++;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200291
292 if (mi->sample_deferred > 0)
293 mi->sample_deferred--;
Johannes Berg8acbcdd2012-11-15 18:27:56 +0100294
Thomas Huehn91340732015-03-24 21:09:39 +0100295 if (time_after(jiffies, mi->last_stats_update +
Johannes Berg8acbcdd2012-11-15 18:27:56 +0100296 (mp->update_interval * HZ) / 1000))
297 minstrel_update_stats(mp, mi);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200298}
299
300
301static inline unsigned int
302minstrel_get_retry_count(struct minstrel_rate *mr,
Weilong Chenf359d3f2013-12-18 15:44:16 +0800303 struct ieee80211_tx_info *info)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200304{
Felix Fietkau8d819a92014-12-17 13:38:34 +0100305 u8 retry = mr->adjusted_retry_count;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200306
Felix Fietkau991fec02013-04-16 13:38:43 +0200307 if (info->control.use_rts)
Felix Fietkau8d819a92014-12-17 13:38:34 +0100308 retry = max_t(u8, 2, min(mr->stats.retry_count_rtscts, retry));
Felix Fietkau991fec02013-04-16 13:38:43 +0200309 else if (info->control.use_cts_prot)
Felix Fietkau8d819a92014-12-17 13:38:34 +0100310 retry = max_t(u8, 2, min(mr->retry_count_cts, retry));
Felix Fietkaucccf1292008-10-05 18:07:45 +0200311 return retry;
312}
313
314
315static int
316minstrel_get_next_sample(struct minstrel_sta_info *mi)
317{
318 unsigned int sample_ndx;
Thomas Huehn8f157612013-03-04 23:30:03 +0100319 sample_ndx = SAMPLE_TBL(mi, mi->sample_row, mi->sample_column);
320 mi->sample_row++;
Thomas Huehnf744bf82013-03-04 23:30:05 +0100321 if ((int) mi->sample_row >= mi->n_rates) {
Thomas Huehn8f157612013-03-04 23:30:03 +0100322 mi->sample_row = 0;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200323 mi->sample_column++;
324 if (mi->sample_column >= SAMPLE_COLUMNS)
325 mi->sample_column = 0;
326 }
327 return sample_ndx;
328}
329
Johannes Berg2df78162008-10-28 16:49:41 +0100330static void
Johannes Berge6a98542008-10-21 12:40:02 +0200331minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
332 void *priv_sta, struct ieee80211_tx_rate_control *txrc)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200333{
Johannes Berge6a98542008-10-21 12:40:02 +0200334 struct sk_buff *skb = txrc->skb;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200335 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
336 struct minstrel_sta_info *mi = priv_sta;
337 struct minstrel_priv *mp = priv;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200338 struct ieee80211_tx_rate *rate = &info->control.rates[0];
339 struct minstrel_rate *msr, *mr;
340 unsigned int ndx;
Thomas Huehn8f157612013-03-04 23:30:03 +0100341 bool mrr_capable;
Felix Fietkau5c9fc932013-07-15 14:35:06 +0200342 bool prev_sample;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200343 int delta;
Thomas Huehn8f157612013-03-04 23:30:03 +0100344 int sampling_ratio;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200345
Thomas Huehn8f157612013-03-04 23:30:03 +0100346 /* management/no-ack frames do not use rate control */
Luis R. Rodriguez4c6d4f52009-07-16 10:05:41 -0700347 if (rate_control_send_low(sta, priv_sta, txrc))
Felix Fietkaucccf1292008-10-05 18:07:45 +0200348 return;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200349
Thomas Huehn8f157612013-03-04 23:30:03 +0100350 /* check multi-rate-retry capabilities & adjust lookaround_rate */
351 mrr_capable = mp->has_mrr &&
352 !txrc->rts &&
353 !txrc->bss_conf->use_cts_prot;
354 if (mrr_capable)
355 sampling_ratio = mp->lookaround_rate_mrr;
356 else
357 sampling_ratio = mp->lookaround_rate;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200358
Thomas Huehn8f157612013-03-04 23:30:03 +0100359 /* increase sum packet counter */
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200360 mi->total_packets++;
Thomas Huehn8f157612013-03-04 23:30:03 +0100361
Lorenzo Bianconi45966ae2013-08-27 16:59:46 +0200362#ifdef CONFIG_MAC80211_DEBUGFS
363 if (mp->fixed_rate_idx != -1)
364 return;
365#endif
366
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200367 delta = (mi->total_packets * sampling_ratio / 100) -
368 (mi->sample_packets + mi->sample_deferred / 2);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200369
Felix Fietkau06d961a2013-04-22 16:14:43 +0200370 /* delta < 0: no sampling required */
Felix Fietkau5c9fc932013-07-15 14:35:06 +0200371 prev_sample = mi->prev_sample;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200372 mi->prev_sample = false;
373 if (delta < 0 || (!mrr_capable && prev_sample))
374 return;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200375
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200376 if (mi->total_packets >= 10000) {
Felix Fietkau06d961a2013-04-22 16:14:43 +0200377 mi->sample_deferred = 0;
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200378 mi->sample_packets = 0;
379 mi->total_packets = 0;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200380 } else if (delta > mi->n_rates * 2) {
381 /* With multi-rate retry, not every planned sample
382 * attempt actually gets used, due to the way the retry
383 * chain is set up - [max_tp,sample,prob,lowest] for
384 * sample_rate < max_tp.
385 *
386 * If there's too much sampling backlog and the link
387 * starts getting worse, minstrel would start bursting
388 * out lots of sampling frames, which would result
389 * in a large throughput loss. */
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200390 mi->sample_packets += (delta - mi->n_rates * 2);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200391 }
Felix Fietkau06d961a2013-04-22 16:14:43 +0200392
393 /* get next random rate sample */
394 ndx = minstrel_get_next_sample(mi);
395 msr = &mi->r[ndx];
396 mr = &mi->r[mi->max_tp_rate[0]];
397
398 /* Decide if direct ( 1st mrr stage) or indirect (2nd mrr stage)
399 * rate sampling method should be used.
400 * Respect such rates that are not sampled for 20 interations.
401 */
402 if (mrr_capable &&
403 msr->perfect_tx_time > mr->perfect_tx_time &&
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200404 msr->stats.sample_skipped < 20) {
Felix Fietkau06d961a2013-04-22 16:14:43 +0200405 /* Only use IEEE80211_TX_CTL_RATE_CTRL_PROBE to mark
406 * packets that have the sampling rate deferred to the
407 * second MRR stage. Increase the sample counter only
408 * if the deferred sample rate was actually used.
409 * Use the sample_deferred counter to make sure that
410 * the sampling is not done in large bursts */
411 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
412 rate++;
413 mi->sample_deferred++;
414 } else {
Jiri Slaby17dce152015-02-19 12:57:40 +0100415 if (!msr->sample_limit)
Felix Fietkau06d961a2013-04-22 16:14:43 +0200416 return;
417
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200418 mi->sample_packets++;
Felix Fietkau06d961a2013-04-22 16:14:43 +0200419 if (msr->sample_limit > 0)
420 msr->sample_limit--;
421 }
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200422
423 /* If we're not using MRR and the sampling rate already
424 * has a probability of >95%, we shouldn't be attempting
425 * to use it, as this only wastes precious airtime */
Felix Fietkau06d961a2013-04-22 16:14:43 +0200426 if (!mrr_capable &&
Thomas Huehn91340732015-03-24 21:09:39 +0100427 (mi->r[ndx].stats.prob_ewma > MINSTREL_FRAC(95, 100)))
Felix Fietkaucccf1292008-10-05 18:07:45 +0200428 return;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200429
Felix Fietkau06d961a2013-04-22 16:14:43 +0200430 mi->prev_sample = true;
Thomas Huehn8f157612013-03-04 23:30:03 +0100431
Felix Fietkau06d961a2013-04-22 16:14:43 +0200432 rate->idx = mi->r[ndx].rix;
433 rate->count = minstrel_get_retry_count(&mi->r[ndx], info);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200434}
435
436
437static void
Michal Kazior4ee73f32012-04-11 08:47:56 +0200438calc_rate_durations(enum ieee80211_band band,
439 struct minstrel_rate *d,
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200440 struct ieee80211_rate *rate,
441 struct cfg80211_chan_def *chandef)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200442{
443 int erp = !!(rate->flags & IEEE80211_RATE_ERP_G);
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200444 int shift = ieee80211_chandef_get_shift(chandef);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200445
Michal Kazior4ee73f32012-04-11 08:47:56 +0200446 d->perfect_tx_time = ieee80211_frame_duration(band, 1200,
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200447 DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
448 shift);
Michal Kazior4ee73f32012-04-11 08:47:56 +0200449 d->ack_time = ieee80211_frame_duration(band, 10,
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200450 DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
451 shift);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200452}
453
454static void
455init_sample_table(struct minstrel_sta_info *mi)
456{
457 unsigned int i, col, new_idx;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200458 u8 rnd[8];
459
460 mi->sample_column = 0;
Thomas Huehn8f157612013-03-04 23:30:03 +0100461 mi->sample_row = 0;
Thomas Huehnf744bf82013-03-04 23:30:05 +0100462 memset(mi->sample_table, 0xff, SAMPLE_COLUMNS * mi->n_rates);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200463
464 for (col = 0; col < SAMPLE_COLUMNS; col++) {
Karl Beldanf7d8ad82013-11-13 10:54:19 +0100465 prandom_bytes(rnd, sizeof(rnd));
Thomas Huehnf744bf82013-03-04 23:30:05 +0100466 for (i = 0; i < mi->n_rates; i++) {
Thomas Huehnf744bf82013-03-04 23:30:05 +0100467 new_idx = (i + rnd[i & 7]) % mi->n_rates;
Thomas Huehnf744bf82013-03-04 23:30:05 +0100468 while (SAMPLE_TBL(mi, new_idx, col) != 0xff)
469 new_idx = (new_idx + 1) % mi->n_rates;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200470
Thomas Huehnf744bf82013-03-04 23:30:05 +0100471 SAMPLE_TBL(mi, new_idx, col) = i;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200472 }
473 }
474}
475
476static void
477minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
Simon Wunderlich3de805c2013-07-08 16:55:50 +0200478 struct cfg80211_chan_def *chandef,
479 struct ieee80211_sta *sta, void *priv_sta)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200480{
481 struct minstrel_sta_info *mi = priv_sta;
482 struct minstrel_priv *mp = priv;
Christian Lamparterd57854b2008-12-22 15:35:31 +0100483 struct ieee80211_rate *ctl_rate;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200484 unsigned int i, n = 0;
485 unsigned int t_slot = 9; /* FIXME: get real slot time */
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200486 u32 rate_flags;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200487
Felix Fietkau06d961a2013-04-22 16:14:43 +0200488 mi->sta = sta;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200489 mi->lowest_rix = rate_lowest_index(sband, sta);
Christian Lamparterd57854b2008-12-22 15:35:31 +0100490 ctl_rate = &sband->bitrates[mi->lowest_rix];
Michal Kazior4ee73f32012-04-11 08:47:56 +0200491 mi->sp_ack_dur = ieee80211_frame_duration(sband->band, 10,
492 ctl_rate->bitrate,
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200493 !!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1,
494 ieee80211_chandef_get_shift(chandef));
Felix Fietkaucccf1292008-10-05 18:07:45 +0200495
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200496 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
Felix Fietkau06d961a2013-04-22 16:14:43 +0200497 memset(mi->max_tp_rate, 0, sizeof(mi->max_tp_rate));
498 mi->max_prob_rate = 0;
499
Felix Fietkaucccf1292008-10-05 18:07:45 +0200500 for (i = 0; i < sband->n_bitrates; i++) {
501 struct minstrel_rate *mr = &mi->r[n];
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200502 struct minstrel_rate_stats *mrs = &mi->r[n].stats;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200503 unsigned int tx_time = 0, tx_time_cts = 0, tx_time_rtscts = 0;
504 unsigned int tx_time_single;
505 unsigned int cw = mp->cw_min;
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200506 int shift;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200507
508 if (!rate_supported(sta, sband->band, i))
509 continue;
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200510 if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
511 continue;
512
Felix Fietkaucccf1292008-10-05 18:07:45 +0200513 n++;
514 memset(mr, 0, sizeof(*mr));
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200515 memset(mrs, 0, sizeof(*mrs));
Felix Fietkaucccf1292008-10-05 18:07:45 +0200516
517 mr->rix = i;
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200518 shift = ieee80211_chandef_get_shift(chandef);
519 mr->bitrate = DIV_ROUND_UP(sband->bitrates[i].bitrate,
520 (1 << shift) * 5);
521 calc_rate_durations(sband->band, mr, &sband->bitrates[i],
522 chandef);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200523
524 /* calculate maximum number of retransmissions before
525 * fallback (based on maximum segment size) */
Felix Fietkauf4a8cd92008-10-15 19:13:59 +0200526 mr->sample_limit = -1;
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200527 mrs->retry_count = 1;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200528 mr->retry_count_cts = 1;
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200529 mrs->retry_count_rtscts = 1;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200530 tx_time = mr->perfect_tx_time + mi->sp_ack_dur;
531 do {
532 /* add one retransmission */
533 tx_time_single = mr->ack_time + mr->perfect_tx_time;
534
535 /* contention window */
Daniel Halperin8fddddf2011-05-10 19:00:45 -0700536 tx_time_single += (t_slot * cw) >> 1;
537 cw = min((cw << 1) | 1, mp->cw_max);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200538
539 tx_time += tx_time_single;
540 tx_time_cts += tx_time_single + mi->sp_ack_dur;
541 tx_time_rtscts += tx_time_single + 2 * mi->sp_ack_dur;
542 if ((tx_time_cts < mp->segment_size) &&
543 (mr->retry_count_cts < mp->max_retry))
544 mr->retry_count_cts++;
545 if ((tx_time_rtscts < mp->segment_size) &&
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200546 (mrs->retry_count_rtscts < mp->max_retry))
547 mrs->retry_count_rtscts++;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200548 } while ((tx_time < mp->segment_size) &&
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200549 (++mr->stats.retry_count < mp->max_retry));
550 mr->adjusted_retry_count = mrs->retry_count;
Felix Fietkau991fec02013-04-16 13:38:43 +0200551 if (!(sband->bitrates[i].flags & IEEE80211_RATE_ERP_G))
Thomas Huehnca12c0c2014-09-09 23:22:13 +0200552 mr->retry_count_cts = mrs->retry_count;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200553 }
554
555 for (i = n; i < sband->n_bitrates; i++) {
556 struct minstrel_rate *mr = &mi->r[i];
557 mr->rix = -1;
558 }
559
560 mi->n_rates = n;
Thomas Huehn91340732015-03-24 21:09:39 +0100561 mi->last_stats_update = jiffies;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200562
563 init_sample_table(mi);
Felix Fietkau06d961a2013-04-22 16:14:43 +0200564 minstrel_update_rates(mp, mi);
Felix Fietkaucccf1292008-10-05 18:07:45 +0200565}
566
567static void *
568minstrel_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
569{
570 struct ieee80211_supported_band *sband;
571 struct minstrel_sta_info *mi;
572 struct minstrel_priv *mp = priv;
573 struct ieee80211_hw *hw = mp->hw;
574 int max_rates = 0;
575 int i;
576
577 mi = kzalloc(sizeof(struct minstrel_sta_info), gfp);
578 if (!mi)
579 return NULL;
580
581 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
Jiri Slaby8e532172009-05-04 18:04:55 +0200582 sband = hw->wiphy->bands[i];
John W. Linville621ad7c2009-05-05 15:18:26 -0400583 if (sband && sband->n_bitrates > max_rates)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200584 max_rates = sband->n_bitrates;
585 }
586
587 mi->r = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
588 if (!mi->r)
589 goto error;
590
591 mi->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
592 if (!mi->sample_table)
593 goto error1;
594
Thomas Huehn91340732015-03-24 21:09:39 +0100595 mi->last_stats_update = jiffies;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200596 return mi;
597
598error1:
599 kfree(mi->r);
600error:
601 kfree(mi);
602 return NULL;
603}
604
605static void
606minstrel_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
607{
608 struct minstrel_sta_info *mi = priv_sta;
609
610 kfree(mi->sample_table);
611 kfree(mi->r);
612 kfree(mi);
613}
614
Felix Fietkaua0497f92013-02-13 10:51:08 +0100615static void
616minstrel_init_cck_rates(struct minstrel_priv *mp)
617{
618 static const int bitrates[4] = { 10, 20, 55, 110 };
619 struct ieee80211_supported_band *sband;
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200620 u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
Felix Fietkaua0497f92013-02-13 10:51:08 +0100621 int i, j;
622
623 sband = mp->hw->wiphy->bands[IEEE80211_BAND_2GHZ];
624 if (!sband)
625 return;
626
627 for (i = 0, j = 0; i < sband->n_bitrates; i++) {
628 struct ieee80211_rate *rate = &sband->bitrates[i];
629
630 if (rate->flags & IEEE80211_RATE_ERP_G)
631 continue;
632
Simon Wunderlich438b61b2013-07-08 16:55:51 +0200633 if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
634 continue;
635
Felix Fietkaua0497f92013-02-13 10:51:08 +0100636 for (j = 0; j < ARRAY_SIZE(bitrates); j++) {
637 if (rate->bitrate != bitrates[j])
638 continue;
639
640 mp->cck_rates[j] = i;
641 break;
642 }
643 }
644}
645
Felix Fietkaucccf1292008-10-05 18:07:45 +0200646static void *
647minstrel_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
648{
649 struct minstrel_priv *mp;
650
651 mp = kzalloc(sizeof(struct minstrel_priv), GFP_ATOMIC);
652 if (!mp)
653 return NULL;
654
655 /* contention window settings
656 * Just an approximation. Using the per-queue values would complicate
657 * the calculations and is probably unnecessary */
658 mp->cw_min = 15;
659 mp->cw_max = 1023;
660
661 /* number of packets (in %) to use for sampling other rates
662 * sample less often for non-mrr packets, because the overhead
663 * is much higher than with mrr */
664 mp->lookaround_rate = 5;
665 mp->lookaround_rate_mrr = 10;
666
Felix Fietkaucccf1292008-10-05 18:07:45 +0200667 /* maximum time that the hw is allowed to stay in one MRR segment */
668 mp->segment_size = 6000;
669
Johannes Berge6a98542008-10-21 12:40:02 +0200670 if (hw->max_rate_tries > 0)
671 mp->max_retry = hw->max_rate_tries;
Felix Fietkaucccf1292008-10-05 18:07:45 +0200672 else
673 /* safe default, does not necessarily have to match hw properties */
674 mp->max_retry = 7;
675
Johannes Berge6a98542008-10-21 12:40:02 +0200676 if (hw->max_rates >= 4)
Felix Fietkaucccf1292008-10-05 18:07:45 +0200677 mp->has_mrr = true;
678
679 mp->hw = hw;
680 mp->update_interval = 100;
681
Zefir Kurtisi24f75802011-05-20 20:29:17 +0200682#ifdef CONFIG_MAC80211_DEBUGFS
683 mp->fixed_rate_idx = (u32) -1;
684 mp->dbg_fixed_rate = debugfs_create_u32("fixed_rate_idx",
685 S_IRUGO | S_IWUGO, debugfsdir, &mp->fixed_rate_idx);
686#endif
687
Felix Fietkaua0497f92013-02-13 10:51:08 +0100688 minstrel_init_cck_rates(mp);
689
Felix Fietkaucccf1292008-10-05 18:07:45 +0200690 return mp;
691}
692
693static void
694minstrel_free(void *priv)
695{
Zefir Kurtisi24f75802011-05-20 20:29:17 +0200696#ifdef CONFIG_MAC80211_DEBUGFS
697 debugfs_remove(((struct minstrel_priv *)priv)->dbg_fixed_rate);
698#endif
Felix Fietkaucccf1292008-10-05 18:07:45 +0200699 kfree(priv);
700}
701
Antonio Quartullicca674d2014-05-19 21:53:20 +0200702static u32 minstrel_get_expected_throughput(void *priv_sta)
703{
704 struct minstrel_sta_info *mi = priv_sta;
Thomas Huehn50e55a82015-03-24 21:09:41 +0100705 struct minstrel_rate_stats *tmp_mrs;
Antonio Quartullicca674d2014-05-19 21:53:20 +0200706 int idx = mi->max_tp_rate[0];
Thomas Huehn6a27b2c2015-03-24 21:09:40 +0100707 int tmp_cur_tp;
Antonio Quartullicca674d2014-05-19 21:53:20 +0200708
709 /* convert pkt per sec in kbps (1200 is the average pkt size used for
710 * computing cur_tp
711 */
Thomas Huehn50e55a82015-03-24 21:09:41 +0100712 tmp_mrs = &mi->r[idx].stats;
713 tmp_cur_tp = minstrel_get_tp_avg(&mi->r[idx], tmp_mrs->prob_ewma);
Thomas Huehn6a27b2c2015-03-24 21:09:40 +0100714 tmp_cur_tp = tmp_cur_tp * 1200 * 8 / 1024;
715
716 return tmp_cur_tp;
Antonio Quartullicca674d2014-05-19 21:53:20 +0200717}
718
Johannes Berg631ad702014-01-20 23:29:34 +0100719const struct rate_control_ops mac80211_minstrel = {
Felix Fietkaucccf1292008-10-05 18:07:45 +0200720 .name = "minstrel",
Felix Fietkaufb7acfb2014-11-19 20:08:09 +0100721 .tx_status_noskb = minstrel_tx_status,
Felix Fietkaucccf1292008-10-05 18:07:45 +0200722 .get_rate = minstrel_get_rate,
723 .rate_init = minstrel_rate_init,
Felix Fietkaucccf1292008-10-05 18:07:45 +0200724 .alloc = minstrel_alloc,
725 .free = minstrel_free,
726 .alloc_sta = minstrel_alloc_sta,
727 .free_sta = minstrel_free_sta,
728#ifdef CONFIG_MAC80211_DEBUGFS
729 .add_sta_debugfs = minstrel_add_sta_debugfs,
730 .remove_sta_debugfs = minstrel_remove_sta_debugfs,
731#endif
Antonio Quartullicca674d2014-05-19 21:53:20 +0200732 .get_expected_throughput = minstrel_get_expected_throughput,
Felix Fietkaucccf1292008-10-05 18:07:45 +0200733};
734
735int __init
736rc80211_minstrel_init(void)
737{
738 return ieee80211_rate_control_register(&mac80211_minstrel);
739}
740
741void
742rc80211_minstrel_exit(void)
743{
744 ieee80211_rate_control_unregister(&mac80211_minstrel);
745}
746