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
rix_to_ndx(struct minstrel_sta_info * mi,int rix)63 rix_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;
69 return i;
70 }
71
72 /* return current EMWA throughput */
minstrel_get_tp_avg(struct minstrel_rate * mr,int prob_avg)73 int minstrel_get_tp_avg(struct minstrel_rate *mr, int prob_avg)
74 {
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_avg < MINSTREL_FRAC(10, 100))
83 return 0;
84
85 if (prob_avg > MINSTREL_FRAC(90, 100))
86 return MINSTREL_TRUNC(100000 * (MINSTREL_FRAC(90, 100) / usecs));
87 else
88 return MINSTREL_TRUNC(100000 * (prob_avg / usecs));
89 }
90
91 /* find & sort topmost throughput rates */
92 static inline void
minstrel_sort_best_tp_rates(struct minstrel_sta_info * mi,int i,u8 * tp_list)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
minstrel_set_rate(struct minstrel_sta_info * mi,struct ieee80211_sta_rates * ratetbl,int offset,int idx)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
minstrel_update_rates(struct minstrel_priv * mp,struct minstrel_sta_info * mi)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
minstrel_calc_rate_stats(struct minstrel_priv * mp,struct minstrel_rate_stats * mrs)160 minstrel_calc_rate_stats(struct minstrel_priv *mp,
161 struct minstrel_rate_stats *mrs)
162 {
163 unsigned int cur_prob;
164
165 if (unlikely(mrs->attempts > 0)) {
166 mrs->sample_skipped = 0;
167 cur_prob = MINSTREL_FRAC(mrs->success, mrs->attempts);
168 if (mp->new_avg) {
169 minstrel_filter_avg_add(&mrs->prob_avg,
170 &mrs->prob_avg_1, cur_prob);
171 } else if (unlikely(!mrs->att_hist)) {
172 mrs->prob_avg = cur_prob;
173 } else {
174 /*update exponential weighted moving avarage */
175 mrs->prob_avg = minstrel_ewma(mrs->prob_avg,
176 cur_prob,
177 EWMA_LEVEL);
178 }
179 mrs->att_hist += mrs->attempts;
180 mrs->succ_hist += mrs->success;
181 } else {
182 mrs->sample_skipped++;
183 }
184
185 mrs->last_success = mrs->success;
186 mrs->last_attempts = mrs->attempts;
187 mrs->success = 0;
188 mrs->attempts = 0;
189 }
190
191 static void
minstrel_update_stats(struct minstrel_priv * mp,struct minstrel_sta_info * mi)192 minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
193 {
194 u8 tmp_tp_rate[MAX_THR_RATES];
195 u8 tmp_prob_rate = 0;
196 int i, tmp_cur_tp, tmp_prob_tp;
197
198 for (i = 0; i < MAX_THR_RATES; i++)
199 tmp_tp_rate[i] = 0;
200
201 for (i = 0; i < mi->n_rates; i++) {
202 struct minstrel_rate *mr = &mi->r[i];
203 struct minstrel_rate_stats *mrs = &mi->r[i].stats;
204 struct minstrel_rate_stats *tmp_mrs = &mi->r[tmp_prob_rate].stats;
205
206 /* Update statistics of success probability per rate */
207 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 if (mrs->prob_avg > MINSTREL_FRAC(95, 100) ||
212 mrs->prob_avg < MINSTREL_FRAC(10, 100)) {
213 mr->adjusted_retry_count = mrs->retry_count >> 1;
214 if (mr->adjusted_retry_count > 2)
215 mr->adjusted_retry_count = 2;
216 mr->sample_limit = 4;
217 } else {
218 mr->sample_limit = -1;
219 mr->adjusted_retry_count = mrs->retry_count;
220 }
221 if (!mr->adjusted_retry_count)
222 mr->adjusted_retry_count = 2;
223
224 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 if (mrs->prob_avg >= MINSTREL_FRAC(95, 100)) {
233 tmp_cur_tp = minstrel_get_tp_avg(mr, mrs->prob_avg);
234 tmp_prob_tp = minstrel_get_tp_avg(&mi->r[tmp_prob_rate],
235 tmp_mrs->prob_avg);
236 if (tmp_cur_tp >= tmp_prob_tp)
237 tmp_prob_rate = i;
238 } else {
239 if (mrs->prob_avg >= tmp_mrs->prob_avg)
240 tmp_prob_rate = i;
241 }
242 }
243
244 /* Assign the new rate set */
245 memcpy(mi->max_tp_rate, tmp_tp_rate, sizeof(mi->max_tp_rate));
246 mi->max_prob_rate = tmp_prob_rate;
247
248 #ifdef CONFIG_MAC80211_DEBUGFS
249 /* use fixed index if set */
250 if (mp->fixed_rate_idx != -1) {
251 mi->max_tp_rate[0] = mp->fixed_rate_idx;
252 mi->max_tp_rate[1] = mp->fixed_rate_idx;
253 mi->max_prob_rate = mp->fixed_rate_idx;
254 }
255 #endif
256
257 /* Reset update timer */
258 mi->last_stats_update = jiffies;
259
260 minstrel_update_rates(mp, mi);
261 }
262
263 static void
minstrel_tx_status(void * priv,struct ieee80211_supported_band * sband,void * priv_sta,struct ieee80211_tx_status * st)264 minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband,
265 void *priv_sta, struct ieee80211_tx_status *st)
266 {
267 struct ieee80211_tx_info *info = st->info;
268 struct minstrel_priv *mp = priv;
269 struct minstrel_sta_info *mi = priv_sta;
270 struct ieee80211_tx_rate *ar = info->status.rates;
271 int i, ndx;
272 int success;
273
274 success = !!(info->flags & IEEE80211_TX_STAT_ACK);
275
276 for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
277 if (ar[i].idx < 0 || !ar[i].count)
278 break;
279
280 ndx = rix_to_ndx(mi, ar[i].idx);
281 if (ndx < 0)
282 continue;
283
284 mi->r[ndx].stats.attempts += ar[i].count;
285
286 if ((i != IEEE80211_TX_MAX_RATES - 1) && (ar[i + 1].idx < 0))
287 mi->r[ndx].stats.success += success;
288 }
289
290 if (time_after(jiffies, mi->last_stats_update +
291 mp->update_interval / (mp->new_avg ? 2 : 1)))
292 minstrel_update_stats(mp, mi);
293 }
294
295
296 static inline unsigned int
minstrel_get_retry_count(struct minstrel_rate * mr,struct ieee80211_tx_info * info)297 minstrel_get_retry_count(struct minstrel_rate *mr,
298 struct ieee80211_tx_info *info)
299 {
300 u8 retry = mr->adjusted_retry_count;
301
302 if (info->control.use_rts)
303 retry = max_t(u8, 2, min(mr->stats.retry_count_rtscts, retry));
304 else if (info->control.use_cts_prot)
305 retry = max_t(u8, 2, min(mr->retry_count_cts, retry));
306 return retry;
307 }
308
309
310 static int
minstrel_get_next_sample(struct minstrel_sta_info * mi)311 minstrel_get_next_sample(struct minstrel_sta_info *mi)
312 {
313 unsigned int sample_ndx;
314 sample_ndx = SAMPLE_TBL(mi, mi->sample_row, mi->sample_column);
315 mi->sample_row++;
316 if ((int) mi->sample_row >= mi->n_rates) {
317 mi->sample_row = 0;
318 mi->sample_column++;
319 if (mi->sample_column >= SAMPLE_COLUMNS)
320 mi->sample_column = 0;
321 }
322 return sample_ndx;
323 }
324
325 static void
minstrel_get_rate(void * priv,struct ieee80211_sta * sta,void * priv_sta,struct ieee80211_tx_rate_control * txrc)326 minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
327 void *priv_sta, struct ieee80211_tx_rate_control *txrc)
328 {
329 struct sk_buff *skb = txrc->skb;
330 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
331 struct minstrel_sta_info *mi = priv_sta;
332 struct minstrel_priv *mp = priv;
333 struct ieee80211_tx_rate *rate = &info->control.rates[0];
334 struct minstrel_rate *msr, *mr;
335 unsigned int ndx;
336 bool mrr_capable;
337 bool prev_sample;
338 int delta;
339 int sampling_ratio;
340
341 /* check multi-rate-retry capabilities & adjust lookaround_rate */
342 mrr_capable = mp->has_mrr &&
343 !txrc->rts &&
344 !txrc->bss_conf->use_cts_prot;
345 if (mrr_capable)
346 sampling_ratio = mp->lookaround_rate_mrr;
347 else
348 sampling_ratio = mp->lookaround_rate;
349
350 /* increase sum packet counter */
351 mi->total_packets++;
352
353 #ifdef CONFIG_MAC80211_DEBUGFS
354 if (mp->fixed_rate_idx != -1)
355 return;
356 #endif
357
358 /* Don't use EAPOL frames for sampling on non-mrr hw */
359 if (mp->hw->max_rates == 1 &&
360 (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
361 return;
362
363 delta = (mi->total_packets * sampling_ratio / 100) -
364 mi->sample_packets;
365
366 /* delta < 0: no sampling required */
367 prev_sample = mi->prev_sample;
368 mi->prev_sample = false;
369 if (delta < 0 || (!mrr_capable && prev_sample))
370 return;
371
372 if (mi->total_packets >= 10000) {
373 mi->sample_packets = 0;
374 mi->total_packets = 0;
375 } else if (delta > mi->n_rates * 2) {
376 /* With multi-rate retry, not every planned sample
377 * attempt actually gets used, due to the way the retry
378 * chain is set up - [max_tp,sample,prob,lowest] for
379 * sample_rate < max_tp.
380 *
381 * If there's too much sampling backlog and the link
382 * starts getting worse, minstrel would start bursting
383 * out lots of sampling frames, which would result
384 * in a large throughput loss. */
385 mi->sample_packets += (delta - mi->n_rates * 2);
386 }
387
388 /* get next random rate sample */
389 ndx = minstrel_get_next_sample(mi);
390 msr = &mi->r[ndx];
391 mr = &mi->r[mi->max_tp_rate[0]];
392
393 /* Decide if direct ( 1st mrr stage) or indirect (2nd mrr stage)
394 * rate sampling method should be used.
395 * Respect such rates that are not sampled for 20 interations.
396 */
397 if (msr->perfect_tx_time < mr->perfect_tx_time ||
398 msr->stats.sample_skipped >= 20) {
399 if (!msr->sample_limit)
400 return;
401
402 mi->sample_packets++;
403 if (msr->sample_limit > 0)
404 msr->sample_limit--;
405 }
406
407 /* If we're not using MRR and the sampling rate already
408 * has a probability of >95%, we shouldn't be attempting
409 * to use it, as this only wastes precious airtime */
410 if (!mrr_capable &&
411 (mi->r[ndx].stats.prob_avg > MINSTREL_FRAC(95, 100)))
412 return;
413
414 mi->prev_sample = true;
415
416 rate->idx = mi->r[ndx].rix;
417 rate->count = minstrel_get_retry_count(&mi->r[ndx], info);
418 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
419 }
420
421
422 static void
calc_rate_durations(enum nl80211_band band,struct minstrel_rate * d,struct ieee80211_rate * rate,struct cfg80211_chan_def * chandef)423 calc_rate_durations(enum nl80211_band band,
424 struct minstrel_rate *d,
425 struct ieee80211_rate *rate,
426 struct cfg80211_chan_def *chandef)
427 {
428 int erp = !!(rate->flags & IEEE80211_RATE_ERP_G);
429 int shift = ieee80211_chandef_get_shift(chandef);
430
431 d->perfect_tx_time = ieee80211_frame_duration(band, 1200,
432 DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
433 shift);
434 d->ack_time = ieee80211_frame_duration(band, 10,
435 DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
436 shift);
437 }
438
439 static void
init_sample_table(struct minstrel_sta_info * mi)440 init_sample_table(struct minstrel_sta_info *mi)
441 {
442 unsigned int i, col, new_idx;
443 u8 rnd[8];
444
445 mi->sample_column = 0;
446 mi->sample_row = 0;
447 memset(mi->sample_table, 0xff, SAMPLE_COLUMNS * mi->n_rates);
448
449 for (col = 0; col < SAMPLE_COLUMNS; col++) {
450 prandom_bytes(rnd, sizeof(rnd));
451 for (i = 0; i < mi->n_rates; i++) {
452 new_idx = (i + rnd[i & 7]) % mi->n_rates;
453 while (SAMPLE_TBL(mi, new_idx, col) != 0xff)
454 new_idx = (new_idx + 1) % mi->n_rates;
455
456 SAMPLE_TBL(mi, new_idx, col) = i;
457 }
458 }
459 }
460
461 static void
minstrel_rate_init(void * priv,struct ieee80211_supported_band * sband,struct cfg80211_chan_def * chandef,struct ieee80211_sta * sta,void * priv_sta)462 minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
463 struct cfg80211_chan_def *chandef,
464 struct ieee80211_sta *sta, void *priv_sta)
465 {
466 struct minstrel_sta_info *mi = priv_sta;
467 struct minstrel_priv *mp = priv;
468 struct ieee80211_rate *ctl_rate;
469 unsigned int i, n = 0;
470 unsigned int t_slot = 9; /* FIXME: get real slot time */
471 u32 rate_flags;
472
473 mi->sta = sta;
474 mi->lowest_rix = rate_lowest_index(sband, sta);
475 ctl_rate = &sband->bitrates[mi->lowest_rix];
476 mi->sp_ack_dur = ieee80211_frame_duration(sband->band, 10,
477 ctl_rate->bitrate,
478 !!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1,
479 ieee80211_chandef_get_shift(chandef));
480
481 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
482 memset(mi->max_tp_rate, 0, sizeof(mi->max_tp_rate));
483 mi->max_prob_rate = 0;
484
485 for (i = 0; i < sband->n_bitrates; i++) {
486 struct minstrel_rate *mr = &mi->r[n];
487 struct minstrel_rate_stats *mrs = &mi->r[n].stats;
488 unsigned int tx_time = 0, tx_time_cts = 0, tx_time_rtscts = 0;
489 unsigned int tx_time_single;
490 unsigned int cw = mp->cw_min;
491 int shift;
492
493 if (!rate_supported(sta, sband->band, i))
494 continue;
495 if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
496 continue;
497
498 n++;
499 memset(mr, 0, sizeof(*mr));
500 memset(mrs, 0, sizeof(*mrs));
501
502 mr->rix = i;
503 shift = ieee80211_chandef_get_shift(chandef);
504 mr->bitrate = DIV_ROUND_UP(sband->bitrates[i].bitrate,
505 (1 << shift) * 5);
506 calc_rate_durations(sband->band, mr, &sband->bitrates[i],
507 chandef);
508
509 /* calculate maximum number of retransmissions before
510 * fallback (based on maximum segment size) */
511 mr->sample_limit = -1;
512 mrs->retry_count = 1;
513 mr->retry_count_cts = 1;
514 mrs->retry_count_rtscts = 1;
515 tx_time = mr->perfect_tx_time + mi->sp_ack_dur;
516 do {
517 /* add one retransmission */
518 tx_time_single = mr->ack_time + mr->perfect_tx_time;
519
520 /* contention window */
521 tx_time_single += (t_slot * cw) >> 1;
522 cw = min((cw << 1) | 1, mp->cw_max);
523
524 tx_time += tx_time_single;
525 tx_time_cts += tx_time_single + mi->sp_ack_dur;
526 tx_time_rtscts += tx_time_single + 2 * mi->sp_ack_dur;
527 if ((tx_time_cts < mp->segment_size) &&
528 (mr->retry_count_cts < mp->max_retry))
529 mr->retry_count_cts++;
530 if ((tx_time_rtscts < mp->segment_size) &&
531 (mrs->retry_count_rtscts < mp->max_retry))
532 mrs->retry_count_rtscts++;
533 } while ((tx_time < mp->segment_size) &&
534 (++mr->stats.retry_count < mp->max_retry));
535 mr->adjusted_retry_count = mrs->retry_count;
536 if (!(sband->bitrates[i].flags & IEEE80211_RATE_ERP_G))
537 mr->retry_count_cts = mrs->retry_count;
538 }
539
540 for (i = n; i < sband->n_bitrates; i++) {
541 struct minstrel_rate *mr = &mi->r[i];
542 mr->rix = -1;
543 }
544
545 mi->n_rates = n;
546 mi->last_stats_update = jiffies;
547
548 init_sample_table(mi);
549 minstrel_update_rates(mp, mi);
550 }
551
minstrel_get_expected_throughput(void * priv_sta)552 static u32 minstrel_get_expected_throughput(void *priv_sta)
553 {
554 struct minstrel_sta_info *mi = priv_sta;
555 struct minstrel_rate_stats *tmp_mrs;
556 int idx = mi->max_tp_rate[0];
557 int tmp_cur_tp;
558
559 /* convert pkt per sec in kbps (1200 is the average pkt size used for
560 * computing cur_tp
561 */
562 tmp_mrs = &mi->r[idx].stats;
563 tmp_cur_tp = minstrel_get_tp_avg(&mi->r[idx], tmp_mrs->prob_avg) * 10;
564 tmp_cur_tp = tmp_cur_tp * 1200 * 8 / 1024;
565
566 return tmp_cur_tp;
567 }
568
569 const struct rate_control_ops mac80211_minstrel = {
570 .tx_status_ext = minstrel_tx_status,
571 .get_rate = minstrel_get_rate,
572 .rate_init = minstrel_rate_init,
573 .get_expected_throughput = minstrel_get_expected_throughput,
574 };
575
