1/* 2 * Copyright (C) 2010-2013 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#include <linux/netdevice.h> 9#include <linux/types.h> 10#include <linux/skbuff.h> 11#include <linux/debugfs.h> 12#include <linux/random.h> 13#include <linux/ieee80211.h> 14#include <net/mac80211.h> 15#include "rate.h" 16#include "rc80211_minstrel.h" 17#include "rc80211_minstrel_ht.h" 18 19#define AVG_PKT_SIZE 1200 20 21/* Number of bits for an average sized packet */ 22#define MCS_NBITS (AVG_PKT_SIZE << 3) 23 24/* Number of symbols for a packet with (bps) bits per symbol */ 25#define MCS_NSYMS(bps) DIV_ROUND_UP(MCS_NBITS, (bps)) 26 27/* Transmission time (nanoseconds) for a packet containing (syms) symbols */ 28#define MCS_SYMBOL_TIME(sgi, syms) \ 29 (sgi ? \ 30 ((syms) * 18000 + 4000) / 5 : /* syms * 3.6 us */ \ 31 ((syms) * 1000) << 2 /* syms * 4 us */ \ 32 ) 33 34/* Transmit duration for the raw data part of an average sized packet */ 35#define MCS_DURATION(streams, sgi, bps) MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps))) 36 37/* 38 * Define group sort order: HT40 -> SGI -> #streams 39 */ 40#define GROUP_IDX(_streams, _sgi, _ht40) \ 41 MINSTREL_MAX_STREAMS * 2 * _ht40 + \ 42 MINSTREL_MAX_STREAMS * _sgi + \ 43 _streams - 1 44 45/* MCS rate information for an MCS group */ 46#define MCS_GROUP(_streams, _sgi, _ht40) \ 47 [GROUP_IDX(_streams, _sgi, _ht40)] = { \ 48 .streams = _streams, \ 49 .flags = \ 50 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \ 51 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \ 52 .duration = { \ 53 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \ 54 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \ 55 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \ 56 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \ 57 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \ 58 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \ 59 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \ 60 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \ 61 } \ 62} 63 64#define CCK_DURATION(_bitrate, _short, _len) \ 65 (1000 * (10 /* SIFS */ + \ 66 (_short ? 72 + 24 : 144 + 48) + \ 67 (8 * (_len + 4) * 10) / (_bitrate))) 68 69#define CCK_ACK_DURATION(_bitrate, _short) \ 70 (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) + \ 71 CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE)) 72 73#define CCK_DURATION_LIST(_short) \ 74 CCK_ACK_DURATION(10, _short), \ 75 CCK_ACK_DURATION(20, _short), \ 76 CCK_ACK_DURATION(55, _short), \ 77 CCK_ACK_DURATION(110, _short) 78 79#define CCK_GROUP \ 80 [MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS] = { \ 81 .streams = 0, \ 82 .duration = { \ 83 CCK_DURATION_LIST(false), \ 84 CCK_DURATION_LIST(true) \ 85 } \ 86 } 87 88/* 89 * To enable sufficiently targeted rate sampling, MCS rates are divided into 90 * groups, based on the number of streams and flags (HT40, SGI) that they 91 * use. 92 * 93 * Sortorder has to be fixed for GROUP_IDX macro to be applicable: 94 * HT40 -> SGI -> #streams 95 */ 96const struct mcs_group minstrel_mcs_groups[] = { 97 MCS_GROUP(1, 0, 0), 98 MCS_GROUP(2, 0, 0), 99#if MINSTREL_MAX_STREAMS >= 3 100 MCS_GROUP(3, 0, 0), 101#endif 102 103 MCS_GROUP(1, 1, 0), 104 MCS_GROUP(2, 1, 0), 105#if MINSTREL_MAX_STREAMS >= 3 106 MCS_GROUP(3, 1, 0), 107#endif 108 109 MCS_GROUP(1, 0, 1), 110 MCS_GROUP(2, 0, 1), 111#if MINSTREL_MAX_STREAMS >= 3 112 MCS_GROUP(3, 0, 1), 113#endif 114 115 MCS_GROUP(1, 1, 1), 116 MCS_GROUP(2, 1, 1), 117#if MINSTREL_MAX_STREAMS >= 3 118 MCS_GROUP(3, 1, 1), 119#endif 120 121 /* must be last */ 122 CCK_GROUP 123}; 124 125#define MINSTREL_CCK_GROUP (ARRAY_SIZE(minstrel_mcs_groups) - 1) 126 127static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly; 128 129static void 130minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi); 131 132/* 133 * Look up an MCS group index based on mac80211 rate information 134 */ 135static int 136minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate) 137{ 138 return GROUP_IDX((rate->idx / MCS_GROUP_RATES) + 1, 139 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI), 140 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH)); 141} 142 143static struct minstrel_rate_stats * 144minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 145 struct ieee80211_tx_rate *rate) 146{ 147 int group, idx; 148 149 if (rate->flags & IEEE80211_TX_RC_MCS) { 150 group = minstrel_ht_get_group_idx(rate); 151 idx = rate->idx % 8; 152 } else { 153 group = MINSTREL_CCK_GROUP; 154 155 for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++) 156 if (rate->idx == mp->cck_rates[idx]) 157 break; 158 159 /* short preamble */ 160 if (!(mi->groups[group].supported & BIT(idx))) 161 idx += 4; 162 } 163 return &mi->groups[group].rates[idx]; 164} 165 166static inline struct minstrel_rate_stats * 167minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index) 168{ 169 return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES]; 170} 171 172 173/* 174 * Recalculate success probabilities and counters for a rate using EWMA 175 */ 176static void 177minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr) 178{ 179 if (unlikely(mr->attempts > 0)) { 180 mr->sample_skipped = 0; 181 mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts); 182 if (!mr->att_hist) 183 mr->probability = mr->cur_prob; 184 else 185 mr->probability = minstrel_ewma(mr->probability, 186 mr->cur_prob, EWMA_LEVEL); 187 mr->att_hist += mr->attempts; 188 mr->succ_hist += mr->success; 189 } else { 190 mr->sample_skipped++; 191 } 192 mr->last_success = mr->success; 193 mr->last_attempts = mr->attempts; 194 mr->success = 0; 195 mr->attempts = 0; 196} 197 198/* 199 * Calculate throughput based on the average A-MPDU length, taking into account 200 * the expected number of retransmissions and their expected length 201 */ 202static void 203minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate) 204{ 205 struct minstrel_rate_stats *mr; 206 unsigned int nsecs = 0; 207 unsigned int tp; 208 unsigned int prob; 209 210 mr = &mi->groups[group].rates[rate]; 211 prob = mr->probability; 212 213 if (prob < MINSTREL_FRAC(1, 10)) { 214 mr->cur_tp = 0; 215 return; 216 } 217 218 /* 219 * For the throughput calculation, limit the probability value to 90% to 220 * account for collision related packet error rate fluctuation 221 */ 222 if (prob > MINSTREL_FRAC(9, 10)) 223 prob = MINSTREL_FRAC(9, 10); 224 225 if (group != MINSTREL_CCK_GROUP) 226 nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len); 227 228 nsecs += minstrel_mcs_groups[group].duration[rate]; 229 230 /* prob is scaled - see MINSTREL_FRAC above */ 231 tp = 1000000 * ((prob * 1000) / nsecs); 232 mr->cur_tp = MINSTREL_TRUNC(tp); 233} 234 235/* 236 * Find & sort topmost throughput rates 237 * 238 * If multiple rates provide equal throughput the sorting is based on their 239 * current success probability. Higher success probability is preferred among 240 * MCS groups, CCK rates do not provide aggregation and are therefore at last. 241 */ 242static void 243minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u8 index, 244 u8 *tp_list) 245{ 246 int cur_group, cur_idx, cur_thr, cur_prob; 247 int tmp_group, tmp_idx, tmp_thr, tmp_prob; 248 int j = MAX_THR_RATES; 249 250 cur_group = index / MCS_GROUP_RATES; 251 cur_idx = index % MCS_GROUP_RATES; 252 cur_thr = mi->groups[cur_group].rates[cur_idx].cur_tp; 253 cur_prob = mi->groups[cur_group].rates[cur_idx].probability; 254 255 do { 256 tmp_group = tp_list[j - 1] / MCS_GROUP_RATES; 257 tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES; 258 tmp_thr = mi->groups[tmp_group].rates[tmp_idx].cur_tp; 259 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability; 260 if (cur_thr < tmp_thr || 261 (cur_thr == tmp_thr && cur_prob <= tmp_prob)) 262 break; 263 j--; 264 } while (j > 0); 265 266 if (j < MAX_THR_RATES - 1) { 267 memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) * 268 (MAX_THR_RATES - (j + 1)))); 269 } 270 if (j < MAX_THR_RATES) 271 tp_list[j] = index; 272} 273 274/* 275 * Find and set the topmost probability rate per sta and per group 276 */ 277static void 278minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u8 index) 279{ 280 struct minstrel_mcs_group_data *mg; 281 struct minstrel_rate_stats *mr; 282 int tmp_group, tmp_idx, tmp_tp, tmp_prob, max_tp_group; 283 284 mg = &mi->groups[index / MCS_GROUP_RATES]; 285 mr = &mg->rates[index % MCS_GROUP_RATES]; 286 287 tmp_group = mi->max_prob_rate / MCS_GROUP_RATES; 288 tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES; 289 tmp_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp; 290 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability; 291 292 /* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from 293 * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */ 294 max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES; 295 if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) && 296 (max_tp_group != MINSTREL_CCK_GROUP)) 297 return; 298 299 if (mr->probability > MINSTREL_FRAC(75, 100)) { 300 if (mr->cur_tp > tmp_tp) 301 mi->max_prob_rate = index; 302 if (mr->cur_tp > mg->rates[mg->max_group_prob_rate].cur_tp) 303 mg->max_group_prob_rate = index; 304 } else { 305 if (mr->probability > tmp_prob) 306 mi->max_prob_rate = index; 307 if (mr->probability > mg->rates[mg->max_group_prob_rate].probability) 308 mg->max_group_prob_rate = index; 309 } 310} 311 312 313/* 314 * Assign new rate set per sta and use CCK rates only if the fastest 315 * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted 316 * rate sets where MCS and CCK rates are mixed, because CCK rates can 317 * not use aggregation. 318 */ 319static void 320minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi, 321 u8 tmp_mcs_tp_rate[MAX_THR_RATES], 322 u8 tmp_cck_tp_rate[MAX_THR_RATES]) 323{ 324 unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp; 325 int i; 326 327 tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES; 328 tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES; 329 tmp_cck_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp; 330 331 tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES; 332 tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES; 333 tmp_mcs_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp; 334 335 if (tmp_cck_tp > tmp_mcs_tp) { 336 for(i = 0; i < MAX_THR_RATES; i++) { 337 minstrel_ht_sort_best_tp_rates(mi, tmp_cck_tp_rate[i], 338 tmp_mcs_tp_rate); 339 } 340 } 341 342} 343 344/* 345 * Try to increase robustness of max_prob rate by decrease number of 346 * streams if possible. 347 */ 348static inline void 349minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi) 350{ 351 struct minstrel_mcs_group_data *mg; 352 struct minstrel_rate_stats *mr; 353 int tmp_max_streams, group; 354 int tmp_tp = 0; 355 356 tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] / 357 MCS_GROUP_RATES].streams; 358 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { 359 mg = &mi->groups[group]; 360 if (!mg->supported || group == MINSTREL_CCK_GROUP) 361 continue; 362 mr = minstrel_get_ratestats(mi, mg->max_group_prob_rate); 363 if (tmp_tp < mr->cur_tp && 364 (minstrel_mcs_groups[group].streams < tmp_max_streams)) { 365 mi->max_prob_rate = mg->max_group_prob_rate; 366 tmp_tp = mr->cur_tp; 367 } 368 } 369} 370 371/* 372 * Update rate statistics and select new primary rates 373 * 374 * Rules for rate selection: 375 * - max_prob_rate must use only one stream, as a tradeoff between delivery 376 * probability and throughput during strong fluctuations 377 * - as long as the max prob rate has a probability of more than 75%, pick 378 * higher throughput rates, even if the probablity is a bit lower 379 */ 380static void 381minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 382{ 383 struct minstrel_mcs_group_data *mg; 384 struct minstrel_rate_stats *mr; 385 int group, i, j; 386 u8 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES]; 387 u8 tmp_cck_tp_rate[MAX_THR_RATES], index; 388 389 if (mi->ampdu_packets > 0) { 390 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len, 391 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL); 392 mi->ampdu_len = 0; 393 mi->ampdu_packets = 0; 394 } 395 396 mi->sample_slow = 0; 397 mi->sample_count = 0; 398 399 /* Initialize global rate indexes */ 400 for(j = 0; j < MAX_THR_RATES; j++){ 401 tmp_mcs_tp_rate[j] = 0; 402 tmp_cck_tp_rate[j] = 0; 403 } 404 405 /* Find best rate sets within all MCS groups*/ 406 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { 407 408 mg = &mi->groups[group]; 409 if (!mg->supported) 410 continue; 411 412 mi->sample_count++; 413 414 /* (re)Initialize group rate indexes */ 415 for(j = 0; j < MAX_THR_RATES; j++) 416 tmp_group_tp_rate[j] = group; 417 418 for (i = 0; i < MCS_GROUP_RATES; i++) { 419 if (!(mg->supported & BIT(i))) 420 continue; 421 422 index = MCS_GROUP_RATES * group + i; 423 424 mr = &mg->rates[i]; 425 mr->retry_updated = false; 426 minstrel_calc_rate_ewma(mr); 427 minstrel_ht_calc_tp(mi, group, i); 428 429 if (!mr->cur_tp) 430 continue; 431 432 /* Find max throughput rate set */ 433 if (group != MINSTREL_CCK_GROUP) { 434 minstrel_ht_sort_best_tp_rates(mi, index, 435 tmp_mcs_tp_rate); 436 } else if (group == MINSTREL_CCK_GROUP) { 437 minstrel_ht_sort_best_tp_rates(mi, index, 438 tmp_cck_tp_rate); 439 } 440 441 /* Find max throughput rate set within a group */ 442 minstrel_ht_sort_best_tp_rates(mi, index, 443 tmp_group_tp_rate); 444 445 /* Find max probability rate per group and global */ 446 minstrel_ht_set_best_prob_rate(mi, index); 447 } 448 449 memcpy(mg->max_group_tp_rate, tmp_group_tp_rate, 450 sizeof(mg->max_group_tp_rate)); 451 } 452 453 /* Assign new rate set per sta */ 454 minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate); 455 memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate)); 456 457 /* Try to increase robustness of max_prob_rate*/ 458 minstrel_ht_prob_rate_reduce_streams(mi); 459 460 /* try to sample all available rates during each interval */ 461 mi->sample_count *= 8; 462 463#ifdef CONFIG_MAC80211_DEBUGFS 464 /* use fixed index if set */ 465 if (mp->fixed_rate_idx != -1) { 466 for (i = 0; i < 4; i++) 467 mi->max_tp_rate[i] = mp->fixed_rate_idx; 468 mi->max_prob_rate = mp->fixed_rate_idx; 469 } 470#endif 471 472 /* Reset update timer */ 473 mi->stats_update = jiffies; 474} 475 476static bool 477minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate) 478{ 479 if (rate->idx < 0) 480 return false; 481 482 if (!rate->count) 483 return false; 484 485 if (rate->flags & IEEE80211_TX_RC_MCS) 486 return true; 487 488 return rate->idx == mp->cck_rates[0] || 489 rate->idx == mp->cck_rates[1] || 490 rate->idx == mp->cck_rates[2] || 491 rate->idx == mp->cck_rates[3]; 492} 493 494static void 495minstrel_next_sample_idx(struct minstrel_ht_sta *mi) 496{ 497 struct minstrel_mcs_group_data *mg; 498 499 for (;;) { 500 mi->sample_group++; 501 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups); 502 mg = &mi->groups[mi->sample_group]; 503 504 if (!mg->supported) 505 continue; 506 507 if (++mg->index >= MCS_GROUP_RATES) { 508 mg->index = 0; 509 if (++mg->column >= ARRAY_SIZE(sample_table)) 510 mg->column = 0; 511 } 512 break; 513 } 514} 515 516static void 517minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u8 *idx, bool primary) 518{ 519 int group, orig_group; 520 521 orig_group = group = *idx / MCS_GROUP_RATES; 522 while (group > 0) { 523 group--; 524 525 if (!mi->groups[group].supported) 526 continue; 527 528 if (minstrel_mcs_groups[group].streams > 529 minstrel_mcs_groups[orig_group].streams) 530 continue; 531 532 if (primary) 533 *idx = mi->groups[group].max_group_tp_rate[0]; 534 else 535 *idx = mi->groups[group].max_group_tp_rate[1]; 536 break; 537 } 538} 539 540static void 541minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb) 542{ 543 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 544 struct sta_info *sta = container_of(pubsta, struct sta_info, sta); 545 u16 tid; 546 547 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control))) 548 return; 549 550 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE))) 551 return; 552 553 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; 554 if (likely(sta->ampdu_mlme.tid_tx[tid])) 555 return; 556 557 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO) 558 return; 559 560 ieee80211_start_tx_ba_session(pubsta, tid, 5000); 561} 562 563static void 564minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, 565 struct ieee80211_sta *sta, void *priv_sta, 566 struct sk_buff *skb) 567{ 568 struct minstrel_ht_sta_priv *msp = priv_sta; 569 struct minstrel_ht_sta *mi = &msp->ht; 570 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 571 struct ieee80211_tx_rate *ar = info->status.rates; 572 struct minstrel_rate_stats *rate, *rate2; 573 struct minstrel_priv *mp = priv; 574 bool last, update = false; 575 int i; 576 577 if (!msp->is_ht) 578 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb); 579 580 /* This packet was aggregated but doesn't carry status info */ 581 if ((info->flags & IEEE80211_TX_CTL_AMPDU) && 582 !(info->flags & IEEE80211_TX_STAT_AMPDU)) 583 return; 584 585 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) { 586 info->status.ampdu_ack_len = 587 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0); 588 info->status.ampdu_len = 1; 589 } 590 591 mi->ampdu_packets++; 592 mi->ampdu_len += info->status.ampdu_len; 593 594 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) { 595 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len); 596 mi->sample_tries = 1; 597 mi->sample_count--; 598 } 599 600 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) 601 mi->sample_packets += info->status.ampdu_len; 602 603 last = !minstrel_ht_txstat_valid(mp, &ar[0]); 604 for (i = 0; !last; i++) { 605 last = (i == IEEE80211_TX_MAX_RATES - 1) || 606 !minstrel_ht_txstat_valid(mp, &ar[i + 1]); 607 608 rate = minstrel_ht_get_stats(mp, mi, &ar[i]); 609 610 if (last) 611 rate->success += info->status.ampdu_ack_len; 612 613 rate->attempts += ar[i].count * info->status.ampdu_len; 614 } 615 616 /* 617 * check for sudden death of spatial multiplexing, 618 * downgrade to a lower number of streams if necessary. 619 */ 620 rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]); 621 if (rate->attempts > 30 && 622 MINSTREL_FRAC(rate->success, rate->attempts) < 623 MINSTREL_FRAC(20, 100)) { 624 minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true); 625 update = true; 626 } 627 628 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]); 629 if (rate2->attempts > 30 && 630 MINSTREL_FRAC(rate2->success, rate2->attempts) < 631 MINSTREL_FRAC(20, 100)) { 632 minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false); 633 update = true; 634 } 635 636 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) { 637 update = true; 638 minstrel_ht_update_stats(mp, mi); 639 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) && 640 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) 641 minstrel_aggr_check(sta, skb); 642 } 643 644 if (update) 645 minstrel_ht_update_rates(mp, mi); 646} 647 648static void 649minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 650 int index) 651{ 652 struct minstrel_rate_stats *mr; 653 const struct mcs_group *group; 654 unsigned int tx_time, tx_time_rtscts, tx_time_data; 655 unsigned int cw = mp->cw_min; 656 unsigned int ctime = 0; 657 unsigned int t_slot = 9; /* FIXME */ 658 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len); 659 unsigned int overhead = 0, overhead_rtscts = 0; 660 661 mr = minstrel_get_ratestats(mi, index); 662 if (mr->probability < MINSTREL_FRAC(1, 10)) { 663 mr->retry_count = 1; 664 mr->retry_count_rtscts = 1; 665 return; 666 } 667 668 mr->retry_count = 2; 669 mr->retry_count_rtscts = 2; 670 mr->retry_updated = true; 671 672 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 673 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000; 674 675 /* Contention time for first 2 tries */ 676 ctime = (t_slot * cw) >> 1; 677 cw = min((cw << 1) | 1, mp->cw_max); 678 ctime += (t_slot * cw) >> 1; 679 cw = min((cw << 1) | 1, mp->cw_max); 680 681 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) { 682 overhead = mi->overhead; 683 overhead_rtscts = mi->overhead_rtscts; 684 } 685 686 /* Total TX time for data and Contention after first 2 tries */ 687 tx_time = ctime + 2 * (overhead + tx_time_data); 688 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data); 689 690 /* See how many more tries we can fit inside segment size */ 691 do { 692 /* Contention time for this try */ 693 ctime = (t_slot * cw) >> 1; 694 cw = min((cw << 1) | 1, mp->cw_max); 695 696 /* Total TX time after this try */ 697 tx_time += ctime + overhead + tx_time_data; 698 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data; 699 700 if (tx_time_rtscts < mp->segment_size) 701 mr->retry_count_rtscts++; 702 } while ((tx_time < mp->segment_size) && 703 (++mr->retry_count < mp->max_retry)); 704} 705 706 707static void 708minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 709 struct ieee80211_sta_rates *ratetbl, int offset, int index) 710{ 711 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 712 struct minstrel_rate_stats *mr; 713 u8 idx; 714 u16 flags; 715 716 mr = minstrel_get_ratestats(mi, index); 717 if (!mr->retry_updated) 718 minstrel_calc_retransmit(mp, mi, index); 719 720 if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) { 721 ratetbl->rate[offset].count = 2; 722 ratetbl->rate[offset].count_rts = 2; 723 ratetbl->rate[offset].count_cts = 2; 724 } else { 725 ratetbl->rate[offset].count = mr->retry_count; 726 ratetbl->rate[offset].count_cts = mr->retry_count; 727 ratetbl->rate[offset].count_rts = mr->retry_count_rtscts; 728 } 729 730 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) { 731 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)]; 732 flags = 0; 733 } else { 734 idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8; 735 flags = IEEE80211_TX_RC_MCS | group->flags; 736 } 737 738 if (offset > 0) { 739 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts; 740 flags |= IEEE80211_TX_RC_USE_RTS_CTS; 741 } 742 743 ratetbl->rate[offset].idx = idx; 744 ratetbl->rate[offset].flags = flags; 745} 746 747static void 748minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 749{ 750 struct ieee80211_sta_rates *rates; 751 int i = 0; 752 753 rates = kzalloc(sizeof(*rates), GFP_ATOMIC); 754 if (!rates) 755 return; 756 757 /* Start with max_tp_rate[0] */ 758 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]); 759 760 if (mp->hw->max_rates >= 3) { 761 /* At least 3 tx rates supported, use max_tp_rate[1] next */ 762 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]); 763 } 764 765 if (mp->hw->max_rates >= 2) { 766 /* 767 * At least 2 tx rates supported, use max_prob_rate next */ 768 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate); 769 } 770 771 rates->rate[i].idx = -1; 772 rate_control_set_rates(mp->hw, mi->sta, rates); 773} 774 775static inline int 776minstrel_get_duration(int index) 777{ 778 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 779 return group->duration[index % MCS_GROUP_RATES]; 780} 781 782static int 783minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 784{ 785 struct minstrel_rate_stats *mr; 786 struct minstrel_mcs_group_data *mg; 787 unsigned int sample_dur, sample_group, cur_max_tp_streams; 788 int sample_idx = 0; 789 790 if (mi->sample_wait > 0) { 791 mi->sample_wait--; 792 return -1; 793 } 794 795 if (!mi->sample_tries) 796 return -1; 797 798 sample_group = mi->sample_group; 799 mg = &mi->groups[sample_group]; 800 sample_idx = sample_table[mg->column][mg->index]; 801 minstrel_next_sample_idx(mi); 802 803 if (!(mg->supported & BIT(sample_idx))) 804 return -1; 805 806 mr = &mg->rates[sample_idx]; 807 sample_idx += sample_group * MCS_GROUP_RATES; 808 809 /* 810 * Sampling might add some overhead (RTS, no aggregation) 811 * to the frame. Hence, don't use sampling for the currently 812 * used rates. 813 */ 814 if (sample_idx == mi->max_tp_rate[0] || 815 sample_idx == mi->max_tp_rate[1] || 816 sample_idx == mi->max_prob_rate) 817 return -1; 818 819 /* 820 * Do not sample if the probability is already higher than 95% 821 * to avoid wasting airtime. 822 */ 823 if (mr->probability > MINSTREL_FRAC(95, 100)) 824 return -1; 825 826 /* 827 * Make sure that lower rates get sampled only occasionally, 828 * if the link is working perfectly. 829 */ 830 831 cur_max_tp_streams = minstrel_mcs_groups[mi->max_tp_rate[0] / 832 MCS_GROUP_RATES].streams; 833 sample_dur = minstrel_get_duration(sample_idx); 834 if (sample_dur >= minstrel_get_duration(mi->max_tp_rate[1]) && 835 (cur_max_tp_streams - 1 < 836 minstrel_mcs_groups[sample_group].streams || 837 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) { 838 if (mr->sample_skipped < 20) 839 return -1; 840 841 if (mi->sample_slow++ > 2) 842 return -1; 843 } 844 mi->sample_tries--; 845 846 return sample_idx; 847} 848 849static void 850minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp, 851 struct minstrel_ht_sta *mi, bool val) 852{ 853 u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported; 854 855 if (!supported || !mi->cck_supported_short) 856 return; 857 858 if (supported & (mi->cck_supported_short << (val * 4))) 859 return; 860 861 supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4); 862 mi->groups[MINSTREL_CCK_GROUP].supported = supported; 863} 864 865static void 866minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, 867 struct ieee80211_tx_rate_control *txrc) 868{ 869 const struct mcs_group *sample_group; 870 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); 871 struct ieee80211_tx_rate *rate = &info->status.rates[0]; 872 struct minstrel_ht_sta_priv *msp = priv_sta; 873 struct minstrel_ht_sta *mi = &msp->ht; 874 struct minstrel_priv *mp = priv; 875 int sample_idx; 876 877 if (rate_control_send_low(sta, priv_sta, txrc)) 878 return; 879 880 if (!msp->is_ht) 881 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc); 882 883 info->flags |= mi->tx_flags; 884 minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble); 885 886#ifdef CONFIG_MAC80211_DEBUGFS 887 if (mp->fixed_rate_idx != -1) 888 return; 889#endif 890 891 /* Don't use EAPOL frames for sampling on non-mrr hw */ 892 if (mp->hw->max_rates == 1 && 893 (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO)) 894 sample_idx = -1; 895 else 896 sample_idx = minstrel_get_sample_rate(mp, mi); 897 898 mi->total_packets++; 899 900 /* wraparound */ 901 if (mi->total_packets == ~0) { 902 mi->total_packets = 0; 903 mi->sample_packets = 0; 904 } 905 906 if (sample_idx < 0) 907 return; 908 909 sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES]; 910 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; 911 rate->count = 1; 912 913 if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) { 914 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates); 915 rate->idx = mp->cck_rates[idx]; 916 rate->flags = 0; 917 return; 918 } 919 920 rate->idx = sample_idx % MCS_GROUP_RATES + 921 (sample_group->streams - 1) * 8; 922 rate->flags = IEEE80211_TX_RC_MCS | sample_group->flags; 923} 924 925static void 926minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 927 struct ieee80211_supported_band *sband, 928 struct ieee80211_sta *sta) 929{ 930 int i; 931 932 if (sband->band != IEEE80211_BAND_2GHZ) 933 return; 934 935 if (!(mp->hw->flags & IEEE80211_HW_SUPPORTS_HT_CCK_RATES)) 936 return; 937 938 mi->cck_supported = 0; 939 mi->cck_supported_short = 0; 940 for (i = 0; i < 4; i++) { 941 if (!rate_supported(sta, sband->band, mp->cck_rates[i])) 942 continue; 943 944 mi->cck_supported |= BIT(i); 945 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE) 946 mi->cck_supported_short |= BIT(i); 947 } 948 949 mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported; 950} 951 952static void 953minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, 954 struct cfg80211_chan_def *chandef, 955 struct ieee80211_sta *sta, void *priv_sta) 956{ 957 struct minstrel_priv *mp = priv; 958 struct minstrel_ht_sta_priv *msp = priv_sta; 959 struct minstrel_ht_sta *mi = &msp->ht; 960 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs; 961 u16 sta_cap = sta->ht_cap.cap; 962 int n_supported = 0; 963 int ack_dur; 964 int stbc; 965 int i; 966 967 /* fall back to the old minstrel for legacy stations */ 968 if (!sta->ht_cap.ht_supported) 969 goto use_legacy; 970 971 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != 972 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1); 973 974 msp->is_ht = true; 975 memset(mi, 0, sizeof(*mi)); 976 977 mi->sta = sta; 978 mi->stats_update = jiffies; 979 980 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0); 981 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0); 982 mi->overhead += ack_dur; 983 mi->overhead_rtscts = mi->overhead + 2 * ack_dur; 984 985 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1); 986 987 /* When using MRR, sample more on the first attempt, without delay */ 988 if (mp->has_mrr) { 989 mi->sample_count = 16; 990 mi->sample_wait = 0; 991 } else { 992 mi->sample_count = 8; 993 mi->sample_wait = 8; 994 } 995 mi->sample_tries = 4; 996 997 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >> 998 IEEE80211_HT_CAP_RX_STBC_SHIFT; 999 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT; 1000 1001 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING) 1002 mi->tx_flags |= IEEE80211_TX_CTL_LDPC; 1003 1004 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) { 1005 mi->groups[i].supported = 0; 1006 if (i == MINSTREL_CCK_GROUP) { 1007 minstrel_ht_update_cck(mp, mi, sband, sta); 1008 continue; 1009 } 1010 1011 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) { 1012 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) { 1013 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40)) 1014 continue; 1015 } else { 1016 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20)) 1017 continue; 1018 } 1019 } 1020 1021 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH && 1022 sta->bandwidth < IEEE80211_STA_RX_BW_40) 1023 continue; 1024 1025 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */ 1026 if (sta->smps_mode == IEEE80211_SMPS_STATIC && 1027 minstrel_mcs_groups[i].streams > 1) 1028 continue; 1029 1030 mi->groups[i].supported = 1031 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1]; 1032 1033 if (mi->groups[i].supported) 1034 n_supported++; 1035 } 1036 1037 if (!n_supported) 1038 goto use_legacy; 1039 1040 /* create an initial rate table with the lowest supported rates */ 1041 minstrel_ht_update_stats(mp, mi); 1042 minstrel_ht_update_rates(mp, mi); 1043 1044 return; 1045 1046use_legacy: 1047 msp->is_ht = false; 1048 memset(&msp->legacy, 0, sizeof(msp->legacy)); 1049 msp->legacy.r = msp->ratelist; 1050 msp->legacy.sample_table = msp->sample_table; 1051 return mac80211_minstrel.rate_init(priv, sband, chandef, sta, 1052 &msp->legacy); 1053} 1054 1055static void 1056minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband, 1057 struct cfg80211_chan_def *chandef, 1058 struct ieee80211_sta *sta, void *priv_sta) 1059{ 1060 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta); 1061} 1062 1063static void 1064minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband, 1065 struct cfg80211_chan_def *chandef, 1066 struct ieee80211_sta *sta, void *priv_sta, 1067 u32 changed) 1068{ 1069 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta); 1070} 1071 1072static void * 1073minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp) 1074{ 1075 struct ieee80211_supported_band *sband; 1076 struct minstrel_ht_sta_priv *msp; 1077 struct minstrel_priv *mp = priv; 1078 struct ieee80211_hw *hw = mp->hw; 1079 int max_rates = 0; 1080 int i; 1081 1082 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 1083 sband = hw->wiphy->bands[i]; 1084 if (sband && sband->n_bitrates > max_rates) 1085 max_rates = sband->n_bitrates; 1086 } 1087 1088 msp = kzalloc(sizeof(*msp), gfp); 1089 if (!msp) 1090 return NULL; 1091 1092 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp); 1093 if (!msp->ratelist) 1094 goto error; 1095 1096 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp); 1097 if (!msp->sample_table) 1098 goto error1; 1099 1100 return msp; 1101 1102error1: 1103 kfree(msp->ratelist); 1104error: 1105 kfree(msp); 1106 return NULL; 1107} 1108 1109static void 1110minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta) 1111{ 1112 struct minstrel_ht_sta_priv *msp = priv_sta; 1113 1114 kfree(msp->sample_table); 1115 kfree(msp->ratelist); 1116 kfree(msp); 1117} 1118 1119static void * 1120minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) 1121{ 1122 return mac80211_minstrel.alloc(hw, debugfsdir); 1123} 1124 1125static void 1126minstrel_ht_free(void *priv) 1127{ 1128 mac80211_minstrel.free(priv); 1129} 1130 1131static u32 minstrel_ht_get_expected_throughput(void *priv_sta) 1132{ 1133 struct minstrel_ht_sta_priv *msp = priv_sta; 1134 struct minstrel_ht_sta *mi = &msp->ht; 1135 int i, j; 1136 1137 if (!msp->is_ht) 1138 return mac80211_minstrel.get_expected_throughput(priv_sta); 1139 1140 i = mi->max_tp_rate[0] / MCS_GROUP_RATES; 1141 j = mi->max_tp_rate[0] % MCS_GROUP_RATES; 1142 1143 /* convert cur_tp from pkt per second in kbps */ 1144 return mi->groups[i].rates[j].cur_tp * AVG_PKT_SIZE * 8 / 1024; 1145} 1146 1147static const struct rate_control_ops mac80211_minstrel_ht = { 1148 .name = "minstrel_ht", 1149 .tx_status = minstrel_ht_tx_status, 1150 .get_rate = minstrel_ht_get_rate, 1151 .rate_init = minstrel_ht_rate_init, 1152 .rate_update = minstrel_ht_rate_update, 1153 .alloc_sta = minstrel_ht_alloc_sta, 1154 .free_sta = minstrel_ht_free_sta, 1155 .alloc = minstrel_ht_alloc, 1156 .free = minstrel_ht_free, 1157#ifdef CONFIG_MAC80211_DEBUGFS 1158 .add_sta_debugfs = minstrel_ht_add_sta_debugfs, 1159 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs, 1160#endif 1161 .get_expected_throughput = minstrel_ht_get_expected_throughput, 1162}; 1163 1164 1165static void __init init_sample_table(void) 1166{ 1167 int col, i, new_idx; 1168 u8 rnd[MCS_GROUP_RATES]; 1169 1170 memset(sample_table, 0xff, sizeof(sample_table)); 1171 for (col = 0; col < SAMPLE_COLUMNS; col++) { 1172 prandom_bytes(rnd, sizeof(rnd)); 1173 for (i = 0; i < MCS_GROUP_RATES; i++) { 1174 new_idx = (i + rnd[i]) % MCS_GROUP_RATES; 1175 while (sample_table[col][new_idx] != 0xff) 1176 new_idx = (new_idx + 1) % MCS_GROUP_RATES; 1177 1178 sample_table[col][new_idx] = i; 1179 } 1180 } 1181} 1182 1183int __init 1184rc80211_minstrel_ht_init(void) 1185{ 1186 init_sample_table(); 1187 return ieee80211_rate_control_register(&mac80211_minstrel_ht); 1188} 1189 1190void 1191rc80211_minstrel_ht_exit(void) 1192{ 1193 ieee80211_rate_control_unregister(&mac80211_minstrel_ht); 1194} 1195