Branch data Line data Source code
1 : : /*
2 : : * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
3 : : *
4 : : * This program is free software; you can redistribute it and/or modify
5 : : * it under the terms of the GNU General Public License version 2 as
6 : : * published by the Free Software Foundation.
7 : : *
8 : : * Based on minstrel.c:
9 : : * Copyright (C) 2005-2007 Derek Smithies <derek@indranet.co.nz>
10 : : * Sponsored by Indranet Technologies Ltd
11 : : *
12 : : * Based on sample.c:
13 : : * Copyright (c) 2005 John Bicket
14 : : * All rights reserved.
15 : : *
16 : : * Redistribution and use in source and binary forms, with or without
17 : : * modification, are permitted provided that the following conditions
18 : : * are met:
19 : : * 1. Redistributions of source code must retain the above copyright
20 : : * notice, this list of conditions and the following disclaimer,
21 : : * without modification.
22 : : * 2. Redistributions in binary form must reproduce at minimum a disclaimer
23 : : * similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
24 : : * redistribution must be conditioned upon including a substantially
25 : : * similar Disclaimer requirement for further binary redistribution.
26 : : * 3. Neither the names of the above-listed copyright holders nor the names
27 : : * of any contributors may be used to endorse or promote products derived
28 : : * from this software without specific prior written permission.
29 : : *
30 : : * Alternatively, this software may be distributed under the terms of the
31 : : * GNU General Public License ("GPL") version 2 as published by the Free
32 : : * Software Foundation.
33 : : *
34 : : * NO WARRANTY
35 : : * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
36 : : * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
37 : : * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
38 : : * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
39 : : * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
40 : : * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
41 : : * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
42 : : * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
43 : : * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
44 : : * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
45 : : * THE POSSIBILITY OF SUCH DAMAGES.
46 : : */
47 : : #include <linux/netdevice.h>
48 : : #include <linux/types.h>
49 : : #include <linux/skbuff.h>
50 : : #include <linux/debugfs.h>
51 : : #include <linux/random.h>
52 : : #include <linux/ieee80211.h>
53 : : #include <linux/slab.h>
54 : : #include <net/mac80211.h>
55 : : #include "rate.h"
56 : : #include "rc80211_minstrel.h"
57 : :
58 : : #define SAMPLE_TBL(_mi, _idx, _col) \
59 : : _mi->sample_table[(_idx * SAMPLE_COLUMNS) + _col]
60 : :
61 : : /* convert mac80211 rate index to local array index */
62 : : static inline int
63 : 0 : rix_to_ndx(struct minstrel_sta_info *mi, int rix)
64 : : {
65 : : int i = rix;
66 [ # # ]: 0 : for (i = rix; i >= 0; i--)
67 [ # # ]: 0 : if (mi->r[i].rix == rix)
68 : : break;
69 : 0 : return i;
70 : : }
71 : :
72 : : /* return current EMWA throughput */
73 : 0 : int minstrel_get_tp_avg(struct minstrel_rate *mr, int prob_avg)
74 : : {
75 : 0 : int usecs;
76 : :
77 : 0 : usecs = mr->perfect_tx_time;
78 [ # # ]: 0 : if (!usecs)
79 : 0 : usecs = 1000000;
80 : :
81 : : /* reset thr. below 10% success */
82 [ # # # # : 0 : if (mr->stats.prob_avg < MINSTREL_FRAC(10, 100))
# # ]
83 : : return 0;
84 : :
85 [ # # # # : 0 : if (prob_avg > MINSTREL_FRAC(90, 100))
# # ]
86 : 0 : return MINSTREL_TRUNC(100000 * (MINSTREL_FRAC(90, 100) / usecs));
87 : : else
88 : 0 : return MINSTREL_TRUNC(100000 * (prob_avg / usecs));
89 : : }
90 : :
91 : : /* find & sort topmost throughput rates */
92 : : static inline void
93 : : minstrel_sort_best_tp_rates(struct minstrel_sta_info *mi, int i, u8 *tp_list)
94 : : {
95 : : int j;
96 : : struct minstrel_rate_stats *tmp_mrs;
97 : : struct minstrel_rate_stats *cur_mrs = &mi->r[i].stats;
98 : :
99 : : for (j = MAX_THR_RATES; j > 0; --j) {
100 : : tmp_mrs = &mi->r[tp_list[j - 1]].stats;
101 : : if (minstrel_get_tp_avg(&mi->r[i], cur_mrs->prob_avg) <=
102 : : minstrel_get_tp_avg(&mi->r[tp_list[j - 1]], tmp_mrs->prob_avg))
103 : : break;
104 : : }
105 : :
106 : : if (j < MAX_THR_RATES - 1)
107 : : memmove(&tp_list[j + 1], &tp_list[j], MAX_THR_RATES - (j + 1));
108 : : if (j < MAX_THR_RATES)
109 : : tp_list[j] = i;
110 : : }
111 : :
112 : : static void
113 : : minstrel_set_rate(struct minstrel_sta_info *mi, struct ieee80211_sta_rates *ratetbl,
114 : : int offset, int idx)
115 : : {
116 : : struct minstrel_rate *r = &mi->r[idx];
117 : :
118 : : ratetbl->rate[offset].idx = r->rix;
119 : : ratetbl->rate[offset].count = r->adjusted_retry_count;
120 : : ratetbl->rate[offset].count_cts = r->retry_count_cts;
121 : : ratetbl->rate[offset].count_rts = r->stats.retry_count_rtscts;
122 : : }
123 : :
124 : : static void
125 : : minstrel_update_rates(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
126 : : {
127 : : struct ieee80211_sta_rates *ratetbl;
128 : : int i = 0;
129 : :
130 : : ratetbl = kzalloc(sizeof(*ratetbl), GFP_ATOMIC);
131 : : if (!ratetbl)
132 : : return;
133 : :
134 : : /* Start with max_tp_rate */
135 : : minstrel_set_rate(mi, ratetbl, i++, mi->max_tp_rate[0]);
136 : :
137 : : if (mp->hw->max_rates >= 3) {
138 : : /* At least 3 tx rates supported, use max_tp_rate2 next */
139 : : minstrel_set_rate(mi, ratetbl, i++, mi->max_tp_rate[1]);
140 : : }
141 : :
142 : : if (mp->hw->max_rates >= 2) {
143 : : /* At least 2 tx rates supported, use max_prob_rate next */
144 : : minstrel_set_rate(mi, ratetbl, i++, mi->max_prob_rate);
145 : : }
146 : :
147 : : /* Use lowest rate last */
148 : : ratetbl->rate[i].idx = mi->lowest_rix;
149 : : ratetbl->rate[i].count = mp->max_retry;
150 : : ratetbl->rate[i].count_cts = mp->max_retry;
151 : : ratetbl->rate[i].count_rts = mp->max_retry;
152 : :
153 : : rate_control_set_rates(mp->hw, mi->sta, ratetbl);
154 : : }
155 : :
156 : : /*
157 : : * Recalculate statistics and counters of a given rate
158 : : */
159 : : void
160 : 0 : minstrel_calc_rate_stats(struct minstrel_priv *mp,
161 : : struct minstrel_rate_stats *mrs)
162 : : {
163 : 0 : unsigned int cur_prob;
164 : :
165 [ # # ]: 0 : if (unlikely(mrs->attempts > 0)) {
166 : 0 : mrs->sample_skipped = 0;
167 : 0 : cur_prob = MINSTREL_FRAC(mrs->success, mrs->attempts);
168 [ # # ]: 0 : if (mp->new_avg) {
169 [ # # ]: 0 : minstrel_filter_avg_add(&mrs->prob_avg,
170 : : &mrs->prob_avg_1, cur_prob);
171 [ # # ]: 0 : } else if (unlikely(!mrs->att_hist)) {
172 : 0 : mrs->prob_avg = cur_prob;
173 : : } else {
174 : : /*update exponential weighted moving avarage */
175 : 0 : mrs->prob_avg = minstrel_ewma(mrs->prob_avg,
176 : : cur_prob,
177 : : EWMA_LEVEL);
178 : : }
179 : 0 : mrs->att_hist += mrs->attempts;
180 : 0 : mrs->succ_hist += mrs->success;
181 : : } else {
182 : 0 : mrs->sample_skipped++;
183 : : }
184 : :
185 : 0 : mrs->last_success = mrs->success;
186 : 0 : mrs->last_attempts = mrs->attempts;
187 : 0 : mrs->success = 0;
188 : 0 : mrs->attempts = 0;
189 : 0 : }
190 : :
191 : : static void
192 : 0 : minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
193 : : {
194 : 0 : u8 tmp_tp_rate[MAX_THR_RATES];
195 : 0 : u8 tmp_prob_rate = 0;
196 : 0 : int i, tmp_cur_tp, tmp_prob_tp;
197 : :
198 [ # # ]: 0 : for (i = 0; i < MAX_THR_RATES; i++)
199 : 0 : tmp_tp_rate[i] = 0;
200 : :
201 [ # # ]: 0 : for (i = 0; i < mi->n_rates; i++) {
202 : 0 : struct minstrel_rate *mr = &mi->r[i];
203 : 0 : struct minstrel_rate_stats *mrs = &mi->r[i].stats;
204 : 0 : struct minstrel_rate_stats *tmp_mrs = &mi->r[tmp_prob_rate].stats;
205 : :
206 : : /* Update statistics of success probability per rate */
207 : 0 : minstrel_calc_rate_stats(mp, mrs);
208 : :
209 : : /* Sample less often below the 10% chance of success.
210 : : * Sample less often above the 95% chance of success. */
211 [ # # ]: 0 : if (mrs->prob_avg > MINSTREL_FRAC(95, 100) ||
212 : : mrs->prob_avg < MINSTREL_FRAC(10, 100)) {
213 : 0 : mr->adjusted_retry_count = mrs->retry_count >> 1;
214 [ # # ]: 0 : if (mr->adjusted_retry_count > 2)
215 : 0 : mr->adjusted_retry_count = 2;
216 : 0 : mr->sample_limit = 4;
217 : : } else {
218 : 0 : mr->sample_limit = -1;
219 : 0 : mr->adjusted_retry_count = mrs->retry_count;
220 : : }
221 [ # # ]: 0 : if (!mr->adjusted_retry_count)
222 : 0 : mr->adjusted_retry_count = 2;
223 : :
224 : 0 : minstrel_sort_best_tp_rates(mi, i, tmp_tp_rate);
225 : :
226 : : /* To determine the most robust rate (max_prob_rate) used at
227 : : * 3rd mmr stage we distinct between two cases:
228 : : * (1) if any success probabilitiy >= 95%, out of those rates
229 : : * choose the maximum throughput rate as max_prob_rate
230 : : * (2) if all success probabilities < 95%, the rate with
231 : : * highest success probability is chosen as max_prob_rate */
232 [ # # ]: 0 : if (mrs->prob_avg >= MINSTREL_FRAC(95, 100)) {
233 [ # # ]: 0 : tmp_cur_tp = minstrel_get_tp_avg(mr, mrs->prob_avg);
234 : 0 : tmp_prob_tp = minstrel_get_tp_avg(&mi->r[tmp_prob_rate],
235 [ # # ]: 0 : tmp_mrs->prob_avg);
236 [ # # ]: 0 : if (tmp_cur_tp >= tmp_prob_tp)
237 : 0 : tmp_prob_rate = i;
238 : : } else {
239 [ # # ]: 0 : if (mrs->prob_avg >= tmp_mrs->prob_avg)
240 : 0 : tmp_prob_rate = i;
241 : : }
242 : : }
243 : :
244 : : /* Assign the new rate set */
245 : 0 : memcpy(mi->max_tp_rate, tmp_tp_rate, sizeof(mi->max_tp_rate));
246 : 0 : mi->max_prob_rate = tmp_prob_rate;
247 : :
248 : : #ifdef CONFIG_MAC80211_DEBUGFS
249 : : /* use fixed index if set */
250 [ # # ]: 0 : if (mp->fixed_rate_idx != -1) {
251 : 0 : mi->max_tp_rate[0] = mp->fixed_rate_idx;
252 : 0 : mi->max_tp_rate[1] = mp->fixed_rate_idx;
253 : 0 : mi->max_prob_rate = mp->fixed_rate_idx;
254 : : }
255 : : #endif
256 : :
257 : : /* Reset update timer */
258 : 0 : mi->last_stats_update = jiffies;
259 : :
260 : 0 : minstrel_update_rates(mp, mi);
261 : 0 : }
262 : :
263 : : static void
264 : 0 : minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband,
265 : : void *priv_sta, struct ieee80211_tx_status *st)
266 : : {
267 : 0 : struct ieee80211_tx_info *info = st->info;
268 : 0 : struct minstrel_priv *mp = priv;
269 : 0 : struct minstrel_sta_info *mi = priv_sta;
270 : 0 : struct ieee80211_tx_rate *ar = info->status.rates;
271 : 0 : int i, ndx;
272 : 0 : int success;
273 : :
274 : 0 : success = !!(info->flags & IEEE80211_TX_STAT_ACK);
275 : :
276 [ # # ]: 0 : for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
277 [ # # ]: 0 : if (ar[i].idx < 0)
278 : : break;
279 : :
280 : 0 : ndx = rix_to_ndx(mi, ar[i].idx);
281 [ # # ]: 0 : if (ndx < 0)
282 : 0 : continue;
283 : :
284 : 0 : mi->r[ndx].stats.attempts += ar[i].count;
285 : :
286 [ # # # # ]: 0 : if ((i != IEEE80211_TX_MAX_RATES - 1) && (ar[i + 1].idx < 0))
287 : 0 : mi->r[ndx].stats.success += success;
288 : : }
289 : :
290 [ # # ]: 0 : if ((info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) && (i >= 0))
291 : 0 : mi->sample_packets++;
292 : :
293 [ # # ]: 0 : if (mi->sample_deferred > 0)
294 : 0 : mi->sample_deferred--;
295 : :
296 [ # # # # ]: 0 : if (time_after(jiffies, mi->last_stats_update +
297 : : mp->update_interval / (mp->new_avg ? 2 : 1)))
298 : 0 : minstrel_update_stats(mp, mi);
299 : 0 : }
300 : :
301 : :
302 : : static inline unsigned int
303 : 0 : minstrel_get_retry_count(struct minstrel_rate *mr,
304 : : struct ieee80211_tx_info *info)
305 : : {
306 : 0 : u8 retry = mr->adjusted_retry_count;
307 : :
308 : 0 : if (info->control.use_rts)
309 : 0 : retry = max_t(u8, 2, min(mr->stats.retry_count_rtscts, retry));
310 [ # # ]: 0 : else if (info->control.use_cts_prot)
311 : 0 : retry = max_t(u8, 2, min(mr->retry_count_cts, retry));
312 : 0 : return retry;
313 : : }
314 : :
315 : :
316 : : static int
317 : 0 : minstrel_get_next_sample(struct minstrel_sta_info *mi)
318 : : {
319 : 0 : unsigned int sample_ndx;
320 : 0 : sample_ndx = SAMPLE_TBL(mi, mi->sample_row, mi->sample_column);
321 : 0 : mi->sample_row++;
322 : 0 : if ((int) mi->sample_row >= mi->n_rates) {
323 : 0 : mi->sample_row = 0;
324 : 0 : mi->sample_column++;
325 [ # # ]: 0 : if (mi->sample_column >= SAMPLE_COLUMNS)
326 : 0 : mi->sample_column = 0;
327 : : }
328 : 0 : return sample_ndx;
329 : : }
330 : :
331 : : static void
332 : 0 : minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
333 : : void *priv_sta, struct ieee80211_tx_rate_control *txrc)
334 : : {
335 : 0 : struct sk_buff *skb = txrc->skb;
336 [ # # ]: 0 : struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
337 : 0 : struct minstrel_sta_info *mi = priv_sta;
338 : 0 : struct minstrel_priv *mp = priv;
339 : 0 : struct ieee80211_tx_rate *rate = &info->control.rates[0];
340 : 0 : struct minstrel_rate *msr, *mr;
341 : 0 : unsigned int ndx;
342 : 0 : bool mrr_capable;
343 : 0 : bool prev_sample;
344 : 0 : int delta;
345 : 0 : int sampling_ratio;
346 : :
347 : : /* check multi-rate-retry capabilities & adjust lookaround_rate */
348 : 0 : mrr_capable = mp->has_mrr &&
349 [ # # # # ]: 0 : !txrc->rts &&
350 [ # # ]: 0 : !txrc->bss_conf->use_cts_prot;
351 [ # # ]: 0 : if (mrr_capable)
352 : 0 : sampling_ratio = mp->lookaround_rate_mrr;
353 : : else
354 : 0 : sampling_ratio = mp->lookaround_rate;
355 : :
356 : : /* increase sum packet counter */
357 : 0 : mi->total_packets++;
358 : :
359 : : #ifdef CONFIG_MAC80211_DEBUGFS
360 [ # # ]: 0 : if (mp->fixed_rate_idx != -1)
361 : : return;
362 : : #endif
363 : :
364 : : /* Don't use EAPOL frames for sampling on non-mrr hw */
365 [ # # ]: 0 : if (mp->hw->max_rates == 1 &&
366 [ # # ]: 0 : (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
367 : : return;
368 : :
369 : 0 : delta = (mi->total_packets * sampling_ratio / 100) -
370 : 0 : (mi->sample_packets + mi->sample_deferred / 2);
371 : :
372 : : /* delta < 0: no sampling required */
373 : 0 : prev_sample = mi->prev_sample;
374 : 0 : mi->prev_sample = false;
375 [ # # # # ]: 0 : if (delta < 0 || (!mrr_capable && prev_sample))
376 : : return;
377 : :
378 [ # # ]: 0 : if (mi->total_packets >= 10000) {
379 : 0 : mi->sample_deferred = 0;
380 : 0 : mi->sample_packets = 0;
381 : 0 : mi->total_packets = 0;
382 [ # # ]: 0 : } else if (delta > mi->n_rates * 2) {
383 : : /* With multi-rate retry, not every planned sample
384 : : * attempt actually gets used, due to the way the retry
385 : : * chain is set up - [max_tp,sample,prob,lowest] for
386 : : * sample_rate < max_tp.
387 : : *
388 : : * If there's too much sampling backlog and the link
389 : : * starts getting worse, minstrel would start bursting
390 : : * out lots of sampling frames, which would result
391 : : * in a large throughput loss. */
392 : 0 : mi->sample_packets += (delta - mi->n_rates * 2);
393 : : }
394 : :
395 : : /* get next random rate sample */
396 [ # # ]: 0 : ndx = minstrel_get_next_sample(mi);
397 : 0 : msr = &mi->r[ndx];
398 : 0 : mr = &mi->r[mi->max_tp_rate[0]];
399 : :
400 : : /* Decide if direct ( 1st mrr stage) or indirect (2nd mrr stage)
401 : : * rate sampling method should be used.
402 : : * Respect such rates that are not sampled for 20 interations.
403 : : */
404 [ # # ]: 0 : if (mrr_capable &&
405 [ # # ]: 0 : msr->perfect_tx_time > mr->perfect_tx_time &&
406 [ # # ]: 0 : msr->stats.sample_skipped < 20) {
407 : : /* Only use IEEE80211_TX_CTL_RATE_CTRL_PROBE to mark
408 : : * packets that have the sampling rate deferred to the
409 : : * second MRR stage. Increase the sample counter only
410 : : * if the deferred sample rate was actually used.
411 : : * Use the sample_deferred counter to make sure that
412 : : * the sampling is not done in large bursts */
413 : 0 : info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
414 : 0 : rate++;
415 : 0 : mi->sample_deferred++;
416 : : } else {
417 [ # # ]: 0 : if (!msr->sample_limit)
418 : : return;
419 : :
420 : 0 : mi->sample_packets++;
421 [ # # ]: 0 : if (msr->sample_limit > 0)
422 : 0 : msr->sample_limit--;
423 : : }
424 : :
425 : : /* If we're not using MRR and the sampling rate already
426 : : * has a probability of >95%, we shouldn't be attempting
427 : : * to use it, as this only wastes precious airtime */
428 [ # # ]: 0 : if (!mrr_capable &&
429 [ # # ]: 0 : (mi->r[ndx].stats.prob_avg > MINSTREL_FRAC(95, 100)))
430 : : return;
431 : :
432 : 0 : mi->prev_sample = true;
433 : :
434 : 0 : rate->idx = mi->r[ndx].rix;
435 [ # # ]: 0 : rate->count = minstrel_get_retry_count(&mi->r[ndx], info);
436 : : }
437 : :
438 : :
439 : : static void
440 : : calc_rate_durations(enum nl80211_band band,
441 : : struct minstrel_rate *d,
442 : : struct ieee80211_rate *rate,
443 : : struct cfg80211_chan_def *chandef)
444 : : {
445 : : int erp = !!(rate->flags & IEEE80211_RATE_ERP_G);
446 : : int shift = ieee80211_chandef_get_shift(chandef);
447 : :
448 : : d->perfect_tx_time = ieee80211_frame_duration(band, 1200,
449 : : DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
450 : : shift);
451 : : d->ack_time = ieee80211_frame_duration(band, 10,
452 : : DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
453 : : shift);
454 : : }
455 : :
456 : : static void
457 : 0 : init_sample_table(struct minstrel_sta_info *mi)
458 : : {
459 : 0 : unsigned int i, col, new_idx;
460 : 0 : u8 rnd[8];
461 : :
462 : 0 : mi->sample_column = 0;
463 : 0 : mi->sample_row = 0;
464 : 0 : memset(mi->sample_table, 0xff, SAMPLE_COLUMNS * mi->n_rates);
465 : :
466 [ # # ]: 0 : for (col = 0; col < SAMPLE_COLUMNS; col++) {
467 : 0 : prandom_bytes(rnd, sizeof(rnd));
468 [ # # ]: 0 : for (i = 0; i < mi->n_rates; i++) {
469 : 0 : new_idx = (i + rnd[i & 7]) % mi->n_rates;
470 [ # # ]: 0 : while (SAMPLE_TBL(mi, new_idx, col) != 0xff)
471 : 0 : new_idx = (new_idx + 1) % mi->n_rates;
472 : :
473 : 0 : SAMPLE_TBL(mi, new_idx, col) = i;
474 : : }
475 : : }
476 : 0 : }
477 : :
478 : : static void
479 : 0 : minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
480 : : struct cfg80211_chan_def *chandef,
481 : : struct ieee80211_sta *sta, void *priv_sta)
482 : : {
483 : 0 : struct minstrel_sta_info *mi = priv_sta;
484 : 0 : struct minstrel_priv *mp = priv;
485 : 0 : struct ieee80211_rate *ctl_rate;
486 : 0 : unsigned int i, n = 0;
487 : 0 : unsigned int t_slot = 9; /* FIXME: get real slot time */
488 : 0 : u32 rate_flags;
489 : :
490 : 0 : mi->sta = sta;
491 : 0 : mi->lowest_rix = rate_lowest_index(sband, sta);
492 : 0 : ctl_rate = &sband->bitrates[mi->lowest_rix];
493 [ # # # ]: 0 : mi->sp_ack_dur = ieee80211_frame_duration(sband->band, 10,
494 : 0 : ctl_rate->bitrate,
495 : 0 : !!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1,
496 : : ieee80211_chandef_get_shift(chandef));
497 : :
498 [ # # # ]: 0 : rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
499 : 0 : memset(mi->max_tp_rate, 0, sizeof(mi->max_tp_rate));
500 : 0 : mi->max_prob_rate = 0;
501 : :
502 [ # # ]: 0 : for (i = 0; i < sband->n_bitrates; i++) {
503 : 0 : struct minstrel_rate *mr = &mi->r[n];
504 : 0 : struct minstrel_rate_stats *mrs = &mi->r[n].stats;
505 : 0 : unsigned int tx_time = 0, tx_time_cts = 0, tx_time_rtscts = 0;
506 : 0 : unsigned int tx_time_single;
507 : 0 : unsigned int cw = mp->cw_min;
508 : 0 : int shift;
509 : :
510 [ # # # # ]: 0 : if (!rate_supported(sta, sband->band, i))
511 : 0 : continue;
512 [ # # ]: 0 : if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
513 : 0 : continue;
514 : :
515 : 0 : n++;
516 : 0 : memset(mr, 0, sizeof(*mr));
517 : 0 : memset(mrs, 0, sizeof(*mrs));
518 : :
519 : 0 : mr->rix = i;
520 [ # # # ]: 0 : shift = ieee80211_chandef_get_shift(chandef);
521 : 0 : mr->bitrate = DIV_ROUND_UP(sband->bitrates[i].bitrate,
522 : : (1 << shift) * 5);
523 : 0 : calc_rate_durations(sband->band, mr, &sband->bitrates[i],
524 : : chandef);
525 : :
526 : : /* calculate maximum number of retransmissions before
527 : : * fallback (based on maximum segment size) */
528 : 0 : mr->sample_limit = -1;
529 : 0 : mrs->retry_count = 1;
530 : 0 : mr->retry_count_cts = 1;
531 : 0 : mrs->retry_count_rtscts = 1;
532 : 0 : tx_time = mr->perfect_tx_time + mi->sp_ack_dur;
533 : 0 : do {
534 : : /* add one retransmission */
535 : 0 : tx_time_single = mr->ack_time + mr->perfect_tx_time;
536 : :
537 : : /* contention window */
538 : 0 : tx_time_single += (t_slot * cw) >> 1;
539 : 0 : cw = min((cw << 1) | 1, mp->cw_max);
540 : :
541 : 0 : tx_time += tx_time_single;
542 : 0 : tx_time_cts += tx_time_single + mi->sp_ack_dur;
543 : 0 : tx_time_rtscts += tx_time_single + 2 * mi->sp_ack_dur;
544 [ # # ]: 0 : if ((tx_time_cts < mp->segment_size) &&
545 [ # # ]: 0 : (mr->retry_count_cts < mp->max_retry))
546 : 0 : mr->retry_count_cts++;
547 [ # # ]: 0 : if ((tx_time_rtscts < mp->segment_size) &&
548 [ # # ]: 0 : (mrs->retry_count_rtscts < mp->max_retry))
549 : 0 : mrs->retry_count_rtscts++;
550 : 0 : } while ((tx_time < mp->segment_size) &&
551 [ # # # # ]: 0 : (++mr->stats.retry_count < mp->max_retry));
552 : 0 : mr->adjusted_retry_count = mrs->retry_count;
553 [ # # ]: 0 : if (!(sband->bitrates[i].flags & IEEE80211_RATE_ERP_G))
554 : 0 : mr->retry_count_cts = mrs->retry_count;
555 : : }
556 : :
557 [ # # ]: 0 : for (i = n; i < sband->n_bitrates; i++) {
558 : 0 : struct minstrel_rate *mr = &mi->r[i];
559 : 0 : mr->rix = -1;
560 : : }
561 : :
562 : 0 : mi->n_rates = n;
563 : 0 : mi->last_stats_update = jiffies;
564 : :
565 : 0 : init_sample_table(mi);
566 : 0 : minstrel_update_rates(mp, mi);
567 : 0 : }
568 : :
569 : 0 : static u32 minstrel_get_expected_throughput(void *priv_sta)
570 : : {
571 : 0 : struct minstrel_sta_info *mi = priv_sta;
572 : 0 : struct minstrel_rate_stats *tmp_mrs;
573 : 0 : int idx = mi->max_tp_rate[0];
574 : 0 : int tmp_cur_tp;
575 : :
576 : : /* convert pkt per sec in kbps (1200 is the average pkt size used for
577 : : * computing cur_tp
578 : : */
579 : 0 : tmp_mrs = &mi->r[idx].stats;
580 [ # # ]: 0 : tmp_cur_tp = minstrel_get_tp_avg(&mi->r[idx], tmp_mrs->prob_avg) * 10;
581 : 0 : tmp_cur_tp = tmp_cur_tp * 1200 * 8 / 1024;
582 : :
583 : 0 : return tmp_cur_tp;
584 : : }
585 : :
586 : : const struct rate_control_ops mac80211_minstrel = {
587 : : .tx_status_ext = minstrel_tx_status,
588 : : .get_rate = minstrel_get_rate,
589 : : .rate_init = minstrel_rate_init,
590 : : .get_expected_throughput = minstrel_get_expected_throughput,
591 : : };
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