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 */ 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; 69 return i; 70} 71 72/* return current EMWA throughput */ 73int minstrel_get_tp_avg(struct minstrel_rate *mr, int prob_ewma) 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_ewma < MINSTREL_FRAC(10, 100)) 83 return 0; 84 85 if (prob_ewma > MINSTREL_FRAC(90, 100)) 86 return MINSTREL_TRUNC(100000 * (MINSTREL_FRAC(90, 100) / usecs)); 87 else 88 return MINSTREL_TRUNC(100000 * (prob_ewma / usecs)); 89} 90 91/* 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; 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_ewma) <= 102 minstrel_get_tp_avg(&mi->r[tp_list[j - 1]], tmp_mrs->prob_ewma)) 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 112static void 113minstrel_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 124static void 125minstrel_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*/ 159void 160minstrel_calc_rate_stats(struct minstrel_rate_stats *mrs) 161{ 162 if (unlikely(mrs->attempts > 0)) { 163 mrs->sample_skipped = 0; 164 mrs->cur_prob = MINSTREL_FRAC(mrs->success, mrs->attempts); 165 if (unlikely(!mrs->att_hist)) { 166 mrs->prob_ewma = mrs->cur_prob; 167 } else { 168 /* update exponential weighted moving variance */ 169 mrs->prob_ewmsd = minstrel_ewmsd(mrs->prob_ewmsd, 170 mrs->cur_prob, 171 mrs->prob_ewma, 172 EWMA_LEVEL); 173 174 /*update exponential weighted moving avarage */ 175 mrs->prob_ewma = minstrel_ewma(mrs->prob_ewma, 176 mrs->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 191static void 192minstrel_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(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_ewma > MINSTREL_FRAC(95, 100) || 212 mrs->prob_ewma < 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_ewma >= MINSTREL_FRAC(95, 100)) { 233 tmp_cur_tp = minstrel_get_tp_avg(mr, mrs->prob_ewma); 234 tmp_prob_tp = minstrel_get_tp_avg(&mi->r[tmp_prob_rate], 235 tmp_mrs->prob_ewma); 236 if (tmp_cur_tp >= tmp_prob_tp) 237 tmp_prob_rate = i; 238 } else { 239 if (mrs->prob_ewma >= tmp_mrs->prob_ewma) 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 263static void 264minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband, 265 struct ieee80211_sta *sta, void *priv_sta, 266 struct ieee80211_tx_info *info) 267{ 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) 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 ((info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) && (i >= 0)) 291 mi->sample_packets++; 292 293 if (mi->sample_deferred > 0) 294 mi->sample_deferred--; 295 296 if (time_after(jiffies, mi->last_stats_update + 297 (mp->update_interval * HZ) / 1000)) 298 minstrel_update_stats(mp, mi); 299} 300 301 302static inline unsigned int 303minstrel_get_retry_count(struct minstrel_rate *mr, 304 struct ieee80211_tx_info *info) 305{ 306 u8 retry = mr->adjusted_retry_count; 307 308 if (info->control.use_rts) 309 retry = max_t(u8, 2, min(mr->stats.retry_count_rtscts, retry)); 310 else if (info->control.use_cts_prot) 311 retry = max_t(u8, 2, min(mr->retry_count_cts, retry)); 312 return retry; 313} 314 315 316static int 317minstrel_get_next_sample(struct minstrel_sta_info *mi) 318{ 319 unsigned int sample_ndx; 320 sample_ndx = SAMPLE_TBL(mi, mi->sample_row, mi->sample_column); 321 mi->sample_row++; 322 if ((int) mi->sample_row >= mi->n_rates) { 323 mi->sample_row = 0; 324 mi->sample_column++; 325 if (mi->sample_column >= SAMPLE_COLUMNS) 326 mi->sample_column = 0; 327 } 328 return sample_ndx; 329} 330 331static void 332minstrel_get_rate(void *priv, struct ieee80211_sta *sta, 333 void *priv_sta, struct ieee80211_tx_rate_control *txrc) 334{ 335 struct sk_buff *skb = txrc->skb; 336 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 337 struct minstrel_sta_info *mi = priv_sta; 338 struct minstrel_priv *mp = priv; 339 struct ieee80211_tx_rate *rate = &info->control.rates[0]; 340 struct minstrel_rate *msr, *mr; 341 unsigned int ndx; 342 bool mrr_capable; 343 bool prev_sample; 344 int delta; 345 int sampling_ratio; 346 347 /* management/no-ack frames do not use rate control */ 348 if (rate_control_send_low(sta, priv_sta, txrc)) 349 return; 350 351 /* check multi-rate-retry capabilities & adjust lookaround_rate */ 352 mrr_capable = mp->has_mrr && 353 !txrc->rts && 354 !txrc->bss_conf->use_cts_prot; 355 if (mrr_capable) 356 sampling_ratio = mp->lookaround_rate_mrr; 357 else 358 sampling_ratio = mp->lookaround_rate; 359 360 /* increase sum packet counter */ 361 mi->total_packets++; 362 363#ifdef CONFIG_MAC80211_DEBUGFS 364 if (mp->fixed_rate_idx != -1) 365 return; 366#endif 367 368 delta = (mi->total_packets * sampling_ratio / 100) - 369 (mi->sample_packets + mi->sample_deferred / 2); 370 371 /* delta < 0: no sampling required */ 372 prev_sample = mi->prev_sample; 373 mi->prev_sample = false; 374 if (delta < 0 || (!mrr_capable && prev_sample)) 375 return; 376 377 if (mi->total_packets >= 10000) { 378 mi->sample_deferred = 0; 379 mi->sample_packets = 0; 380 mi->total_packets = 0; 381 } else if (delta > mi->n_rates * 2) { 382 /* With multi-rate retry, not every planned sample 383 * attempt actually gets used, due to the way the retry 384 * chain is set up - [max_tp,sample,prob,lowest] for 385 * sample_rate < max_tp. 386 * 387 * If there's too much sampling backlog and the link 388 * starts getting worse, minstrel would start bursting 389 * out lots of sampling frames, which would result 390 * in a large throughput loss. */ 391 mi->sample_packets += (delta - mi->n_rates * 2); 392 } 393 394 /* get next random rate sample */ 395 ndx = minstrel_get_next_sample(mi); 396 msr = &mi->r[ndx]; 397 mr = &mi->r[mi->max_tp_rate[0]]; 398 399 /* Decide if direct ( 1st mrr stage) or indirect (2nd mrr stage) 400 * rate sampling method should be used. 401 * Respect such rates that are not sampled for 20 interations. 402 */ 403 if (mrr_capable && 404 msr->perfect_tx_time > mr->perfect_tx_time && 405 msr->stats.sample_skipped < 20) { 406 /* Only use IEEE80211_TX_CTL_RATE_CTRL_PROBE to mark 407 * packets that have the sampling rate deferred to the 408 * second MRR stage. Increase the sample counter only 409 * if the deferred sample rate was actually used. 410 * Use the sample_deferred counter to make sure that 411 * the sampling is not done in large bursts */ 412 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; 413 rate++; 414 mi->sample_deferred++; 415 } else { 416 if (!msr->sample_limit) 417 return; 418 419 mi->sample_packets++; 420 if (msr->sample_limit > 0) 421 msr->sample_limit--; 422 } 423 424 /* If we're not using MRR and the sampling rate already 425 * has a probability of >95%, we shouldn't be attempting 426 * to use it, as this only wastes precious airtime */ 427 if (!mrr_capable && 428 (mi->r[ndx].stats.prob_ewma > MINSTREL_FRAC(95, 100))) 429 return; 430 431 mi->prev_sample = true; 432 433 rate->idx = mi->r[ndx].rix; 434 rate->count = minstrel_get_retry_count(&mi->r[ndx], info); 435} 436 437 438static void 439calc_rate_durations(enum ieee80211_band band, 440 struct minstrel_rate *d, 441 struct ieee80211_rate *rate, 442 struct cfg80211_chan_def *chandef) 443{ 444 int erp = !!(rate->flags & IEEE80211_RATE_ERP_G); 445 int shift = ieee80211_chandef_get_shift(chandef); 446 447 d->perfect_tx_time = ieee80211_frame_duration(band, 1200, 448 DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1, 449 shift); 450 d->ack_time = ieee80211_frame_duration(band, 10, 451 DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1, 452 shift); 453} 454 455static void 456init_sample_table(struct minstrel_sta_info *mi) 457{ 458 unsigned int i, col, new_idx; 459 u8 rnd[8]; 460 461 mi->sample_column = 0; 462 mi->sample_row = 0; 463 memset(mi->sample_table, 0xff, SAMPLE_COLUMNS * mi->n_rates); 464 465 for (col = 0; col < SAMPLE_COLUMNS; col++) { 466 prandom_bytes(rnd, sizeof(rnd)); 467 for (i = 0; i < mi->n_rates; i++) { 468 new_idx = (i + rnd[i & 7]) % mi->n_rates; 469 while (SAMPLE_TBL(mi, new_idx, col) != 0xff) 470 new_idx = (new_idx + 1) % mi->n_rates; 471 472 SAMPLE_TBL(mi, new_idx, col) = i; 473 } 474 } 475} 476 477static void 478minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband, 479 struct cfg80211_chan_def *chandef, 480 struct ieee80211_sta *sta, void *priv_sta) 481{ 482 struct minstrel_sta_info *mi = priv_sta; 483 struct minstrel_priv *mp = priv; 484 struct ieee80211_rate *ctl_rate; 485 unsigned int i, n = 0; 486 unsigned int t_slot = 9; /* FIXME: get real slot time */ 487 u32 rate_flags; 488 489 mi->sta = sta; 490 mi->lowest_rix = rate_lowest_index(sband, sta); 491 ctl_rate = &sband->bitrates[mi->lowest_rix]; 492 mi->sp_ack_dur = ieee80211_frame_duration(sband->band, 10, 493 ctl_rate->bitrate, 494 !!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1, 495 ieee80211_chandef_get_shift(chandef)); 496 497 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef); 498 memset(mi->max_tp_rate, 0, sizeof(mi->max_tp_rate)); 499 mi->max_prob_rate = 0; 500 501 for (i = 0; i < sband->n_bitrates; i++) { 502 struct minstrel_rate *mr = &mi->r[n]; 503 struct minstrel_rate_stats *mrs = &mi->r[n].stats; 504 unsigned int tx_time = 0, tx_time_cts = 0, tx_time_rtscts = 0; 505 unsigned int tx_time_single; 506 unsigned int cw = mp->cw_min; 507 int shift; 508 509 if (!rate_supported(sta, sband->band, i)) 510 continue; 511 if ((rate_flags & sband->bitrates[i].flags) != rate_flags) 512 continue; 513 514 n++; 515 memset(mr, 0, sizeof(*mr)); 516 memset(mrs, 0, sizeof(*mrs)); 517 518 mr->rix = i; 519 shift = ieee80211_chandef_get_shift(chandef); 520 mr->bitrate = DIV_ROUND_UP(sband->bitrates[i].bitrate, 521 (1 << shift) * 5); 522 calc_rate_durations(sband->band, mr, &sband->bitrates[i], 523 chandef); 524 525 /* calculate maximum number of retransmissions before 526 * fallback (based on maximum segment size) */ 527 mr->sample_limit = -1; 528 mrs->retry_count = 1; 529 mr->retry_count_cts = 1; 530 mrs->retry_count_rtscts = 1; 531 tx_time = mr->perfect_tx_time + mi->sp_ack_dur; 532 do { 533 /* add one retransmission */ 534 tx_time_single = mr->ack_time + mr->perfect_tx_time; 535 536 /* contention window */ 537 tx_time_single += (t_slot * cw) >> 1; 538 cw = min((cw << 1) | 1, mp->cw_max); 539 540 tx_time += tx_time_single; 541 tx_time_cts += tx_time_single + mi->sp_ack_dur; 542 tx_time_rtscts += tx_time_single + 2 * mi->sp_ack_dur; 543 if ((tx_time_cts < mp->segment_size) && 544 (mr->retry_count_cts < mp->max_retry)) 545 mr->retry_count_cts++; 546 if ((tx_time_rtscts < mp->segment_size) && 547 (mrs->retry_count_rtscts < mp->max_retry)) 548 mrs->retry_count_rtscts++; 549 } while ((tx_time < mp->segment_size) && 550 (++mr->stats.retry_count < mp->max_retry)); 551 mr->adjusted_retry_count = mrs->retry_count; 552 if (!(sband->bitrates[i].flags & IEEE80211_RATE_ERP_G)) 553 mr->retry_count_cts = mrs->retry_count; 554 } 555 556 for (i = n; i < sband->n_bitrates; i++) { 557 struct minstrel_rate *mr = &mi->r[i]; 558 mr->rix = -1; 559 } 560 561 mi->n_rates = n; 562 mi->last_stats_update = jiffies; 563 564 init_sample_table(mi); 565 minstrel_update_rates(mp, mi); 566} 567 568static void * 569minstrel_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp) 570{ 571 struct ieee80211_supported_band *sband; 572 struct minstrel_sta_info *mi; 573 struct minstrel_priv *mp = priv; 574 struct ieee80211_hw *hw = mp->hw; 575 int max_rates = 0; 576 int i; 577 578 mi = kzalloc(sizeof(struct minstrel_sta_info), gfp); 579 if (!mi) 580 return NULL; 581 582 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 583 sband = hw->wiphy->bands[i]; 584 if (sband && sband->n_bitrates > max_rates) 585 max_rates = sband->n_bitrates; 586 } 587 588 mi->r = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp); 589 if (!mi->r) 590 goto error; 591 592 mi->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp); 593 if (!mi->sample_table) 594 goto error1; 595 596 mi->last_stats_update = jiffies; 597 return mi; 598 599error1: 600 kfree(mi->r); 601error: 602 kfree(mi); 603 return NULL; 604} 605 606static void 607minstrel_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta) 608{ 609 struct minstrel_sta_info *mi = priv_sta; 610 611 kfree(mi->sample_table); 612 kfree(mi->r); 613 kfree(mi); 614} 615 616static void 617minstrel_init_cck_rates(struct minstrel_priv *mp) 618{ 619 static const int bitrates[4] = { 10, 20, 55, 110 }; 620 struct ieee80211_supported_band *sband; 621 u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef); 622 int i, j; 623 624 sband = mp->hw->wiphy->bands[IEEE80211_BAND_2GHZ]; 625 if (!sband) 626 return; 627 628 for (i = 0, j = 0; i < sband->n_bitrates; i++) { 629 struct ieee80211_rate *rate = &sband->bitrates[i]; 630 631 if (rate->flags & IEEE80211_RATE_ERP_G) 632 continue; 633 634 if ((rate_flags & sband->bitrates[i].flags) != rate_flags) 635 continue; 636 637 for (j = 0; j < ARRAY_SIZE(bitrates); j++) { 638 if (rate->bitrate != bitrates[j]) 639 continue; 640 641 mp->cck_rates[j] = i; 642 break; 643 } 644 } 645} 646 647static void * 648minstrel_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) 649{ 650 struct minstrel_priv *mp; 651 652 mp = kzalloc(sizeof(struct minstrel_priv), GFP_ATOMIC); 653 if (!mp) 654 return NULL; 655 656 /* contention window settings 657 * Just an approximation. Using the per-queue values would complicate 658 * the calculations and is probably unnecessary */ 659 mp->cw_min = 15; 660 mp->cw_max = 1023; 661 662 /* number of packets (in %) to use for sampling other rates 663 * sample less often for non-mrr packets, because the overhead 664 * is much higher than with mrr */ 665 mp->lookaround_rate = 5; 666 mp->lookaround_rate_mrr = 10; 667 668 /* maximum time that the hw is allowed to stay in one MRR segment */ 669 mp->segment_size = 6000; 670 671 if (hw->max_rate_tries > 0) 672 mp->max_retry = hw->max_rate_tries; 673 else 674 /* safe default, does not necessarily have to match hw properties */ 675 mp->max_retry = 7; 676 677 if (hw->max_rates >= 4) 678 mp->has_mrr = true; 679 680 mp->hw = hw; 681 mp->update_interval = 100; 682 683#ifdef CONFIG_MAC80211_DEBUGFS 684 mp->fixed_rate_idx = (u32) -1; 685 mp->dbg_fixed_rate = debugfs_create_u32("fixed_rate_idx", 686 S_IRUGO | S_IWUGO, debugfsdir, &mp->fixed_rate_idx); 687#endif 688 689 minstrel_init_cck_rates(mp); 690 691 return mp; 692} 693 694static void 695minstrel_free(void *priv) 696{ 697#ifdef CONFIG_MAC80211_DEBUGFS 698 debugfs_remove(((struct minstrel_priv *)priv)->dbg_fixed_rate); 699#endif 700 kfree(priv); 701} 702 703static u32 minstrel_get_expected_throughput(void *priv_sta) 704{ 705 struct minstrel_sta_info *mi = priv_sta; 706 struct minstrel_rate_stats *tmp_mrs; 707 int idx = mi->max_tp_rate[0]; 708 int tmp_cur_tp; 709 710 /* convert pkt per sec in kbps (1200 is the average pkt size used for 711 * computing cur_tp 712 */ 713 tmp_mrs = &mi->r[idx].stats; 714 tmp_cur_tp = minstrel_get_tp_avg(&mi->r[idx], tmp_mrs->prob_ewma) * 10; 715 tmp_cur_tp = tmp_cur_tp * 1200 * 8 / 1024; 716 717 return tmp_cur_tp; 718} 719 720const struct rate_control_ops mac80211_minstrel = { 721 .name = "minstrel", 722 .tx_status_noskb = minstrel_tx_status, 723 .get_rate = minstrel_get_rate, 724 .rate_init = minstrel_rate_init, 725 .alloc = minstrel_alloc, 726 .free = minstrel_free, 727 .alloc_sta = minstrel_alloc_sta, 728 .free_sta = minstrel_free_sta, 729#ifdef CONFIG_MAC80211_DEBUGFS 730 .add_sta_debugfs = minstrel_add_sta_debugfs, 731 .remove_sta_debugfs = minstrel_remove_sta_debugfs, 732#endif 733 .get_expected_throughput = minstrel_get_expected_throughput, 734}; 735 736int __init 737rc80211_minstrel_init(void) 738{ 739 return ieee80211_rate_control_register(&mac80211_minstrel); 740} 741 742void 743rc80211_minstrel_exit(void) 744{ 745 ieee80211_rate_control_unregister(&mac80211_minstrel); 746} 747 748