1 /* 2 * Copyright (C) 2010 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 #define SAMPLE_COLUMNS 10 21 #define EWMA_LEVEL 75 22 23 /* Number of bits for an average sized packet */ 24 #define MCS_NBITS (AVG_PKT_SIZE << 3) 25 26 /* Number of symbols for a packet with (bps) bits per symbol */ 27 #define MCS_NSYMS(bps) ((MCS_NBITS + (bps) - 1) / (bps)) 28 29 /* Transmission time for a packet containing (syms) symbols */ 30 #define MCS_SYMBOL_TIME(sgi, syms) \ 31 (sgi ? \ 32 ((syms) * 18 + 4) / 5 : /* syms * 3.6 us */ \ 33 (syms) << 2 /* syms * 4 us */ \ 34 ) 35 36 /* Transmit duration for the raw data part of an average sized packet */ 37 #define MCS_DURATION(streams, sgi, bps) MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps))) 38 39 /* 40 * Define group sort order: HT40 -> SGI -> #streams 41 */ 42 #define GROUP_IDX(_streams, _sgi, _ht40) \ 43 MINSTREL_MAX_STREAMS * 2 * _ht40 + \ 44 MINSTREL_MAX_STREAMS * _sgi + \ 45 _streams - 1 46 47 /* MCS rate information for an MCS group */ 48 #define MCS_GROUP(_streams, _sgi, _ht40) \ 49 [GROUP_IDX(_streams, _sgi, _ht40)] = { \ 50 .streams = _streams, \ 51 .flags = \ 52 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \ 53 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \ 54 .duration = { \ 55 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \ 56 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \ 57 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \ 58 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \ 59 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \ 60 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \ 61 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \ 62 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \ 63 } \ 64 } 65 66 /* 67 * To enable sufficiently targeted rate sampling, MCS rates are divided into 68 * groups, based on the number of streams and flags (HT40, SGI) that they 69 * use. 70 * 71 * Sortorder has to be fixed for GROUP_IDX macro to be applicable: 72 * HT40 -> SGI -> #streams 73 */ 74 const struct mcs_group minstrel_mcs_groups[] = { 75 MCS_GROUP(1, 0, 0), 76 MCS_GROUP(2, 0, 0), 77 #if MINSTREL_MAX_STREAMS >= 3 78 MCS_GROUP(3, 0, 0), 79 #endif 80 81 MCS_GROUP(1, 1, 0), 82 MCS_GROUP(2, 1, 0), 83 #if MINSTREL_MAX_STREAMS >= 3 84 MCS_GROUP(3, 1, 0), 85 #endif 86 87 MCS_GROUP(1, 0, 1), 88 MCS_GROUP(2, 0, 1), 89 #if MINSTREL_MAX_STREAMS >= 3 90 MCS_GROUP(3, 0, 1), 91 #endif 92 93 MCS_GROUP(1, 1, 1), 94 MCS_GROUP(2, 1, 1), 95 #if MINSTREL_MAX_STREAMS >= 3 96 MCS_GROUP(3, 1, 1), 97 #endif 98 }; 99 100 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES]; 101 102 /* 103 * Perform EWMA (Exponentially Weighted Moving Average) calculation 104 */ 105 static int 106 minstrel_ewma(int old, int new, int weight) 107 { 108 return (new * (100 - weight) + old * weight) / 100; 109 } 110 111 /* 112 * Look up an MCS group index based on mac80211 rate information 113 */ 114 static int 115 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate) 116 { 117 return GROUP_IDX((rate->idx / MCS_GROUP_RATES) + 1, 118 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI), 119 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH)); 120 } 121 122 static inline struct minstrel_rate_stats * 123 minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index) 124 { 125 return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES]; 126 } 127 128 129 /* 130 * Recalculate success probabilities and counters for a rate using EWMA 131 */ 132 static void 133 minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr) 134 { 135 if (unlikely(mr->attempts > 0)) { 136 mr->sample_skipped = 0; 137 mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts); 138 if (!mr->att_hist) 139 mr->probability = mr->cur_prob; 140 else 141 mr->probability = minstrel_ewma(mr->probability, 142 mr->cur_prob, EWMA_LEVEL); 143 mr->att_hist += mr->attempts; 144 mr->succ_hist += mr->success; 145 } else { 146 mr->sample_skipped++; 147 } 148 mr->last_success = mr->success; 149 mr->last_attempts = mr->attempts; 150 mr->success = 0; 151 mr->attempts = 0; 152 } 153 154 /* 155 * Calculate throughput based on the average A-MPDU length, taking into account 156 * the expected number of retransmissions and their expected length 157 */ 158 static void 159 minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate) 160 { 161 struct minstrel_rate_stats *mr; 162 unsigned int usecs; 163 164 mr = &mi->groups[group].rates[rate]; 165 166 if (mr->probability < MINSTREL_FRAC(1, 10)) { 167 mr->cur_tp = 0; 168 return; 169 } 170 171 usecs = mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len); 172 usecs += minstrel_mcs_groups[group].duration[rate]; 173 mr->cur_tp = MINSTREL_TRUNC((1000000 / usecs) * mr->probability); 174 } 175 176 /* 177 * Update rate statistics and select new primary rates 178 * 179 * Rules for rate selection: 180 * - max_prob_rate must use only one stream, as a tradeoff between delivery 181 * probability and throughput during strong fluctuations 182 * - as long as the max prob rate has a probability of more than 3/4, pick 183 * higher throughput rates, even if the probablity is a bit lower 184 */ 185 static void 186 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 187 { 188 struct minstrel_mcs_group_data *mg; 189 struct minstrel_rate_stats *mr; 190 int cur_prob, cur_prob_tp, cur_tp, cur_tp2; 191 int group, i, index; 192 193 if (mi->ampdu_packets > 0) { 194 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len, 195 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL); 196 mi->ampdu_len = 0; 197 mi->ampdu_packets = 0; 198 } 199 200 mi->sample_slow = 0; 201 mi->sample_count = 0; 202 mi->max_tp_rate = 0; 203 mi->max_tp_rate2 = 0; 204 mi->max_prob_rate = 0; 205 206 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { 207 cur_prob = 0; 208 cur_prob_tp = 0; 209 cur_tp = 0; 210 cur_tp2 = 0; 211 212 mg = &mi->groups[group]; 213 if (!mg->supported) 214 continue; 215 216 mg->max_tp_rate = 0; 217 mg->max_tp_rate2 = 0; 218 mg->max_prob_rate = 0; 219 mi->sample_count++; 220 221 for (i = 0; i < MCS_GROUP_RATES; i++) { 222 if (!(mg->supported & BIT(i))) 223 continue; 224 225 mr = &mg->rates[i]; 226 mr->retry_updated = false; 227 index = MCS_GROUP_RATES * group + i; 228 minstrel_calc_rate_ewma(mr); 229 minstrel_ht_calc_tp(mi, group, i); 230 231 if (!mr->cur_tp) 232 continue; 233 234 /* ignore the lowest rate of each single-stream group */ 235 if (!i && minstrel_mcs_groups[group].streams == 1) 236 continue; 237 238 if ((mr->cur_tp > cur_prob_tp && mr->probability > 239 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) { 240 mg->max_prob_rate = index; 241 cur_prob = mr->probability; 242 cur_prob_tp = mr->cur_tp; 243 } 244 245 if (mr->cur_tp > cur_tp) { 246 swap(index, mg->max_tp_rate); 247 cur_tp = mr->cur_tp; 248 mr = minstrel_get_ratestats(mi, index); 249 } 250 251 if (index >= mg->max_tp_rate) 252 continue; 253 254 if (mr->cur_tp > cur_tp2) { 255 mg->max_tp_rate2 = index; 256 cur_tp2 = mr->cur_tp; 257 } 258 } 259 } 260 261 /* try to sample up to half of the available rates during each interval */ 262 mi->sample_count *= 4; 263 264 cur_prob = 0; 265 cur_prob_tp = 0; 266 cur_tp = 0; 267 cur_tp2 = 0; 268 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { 269 mg = &mi->groups[group]; 270 if (!mg->supported) 271 continue; 272 273 mr = minstrel_get_ratestats(mi, mg->max_prob_rate); 274 if (cur_prob_tp < mr->cur_tp && 275 minstrel_mcs_groups[group].streams == 1) { 276 mi->max_prob_rate = mg->max_prob_rate; 277 cur_prob = mr->cur_prob; 278 cur_prob_tp = mr->cur_tp; 279 } 280 281 mr = minstrel_get_ratestats(mi, mg->max_tp_rate); 282 if (cur_tp < mr->cur_tp) { 283 mi->max_tp_rate2 = mi->max_tp_rate; 284 cur_tp2 = cur_tp; 285 mi->max_tp_rate = mg->max_tp_rate; 286 cur_tp = mr->cur_tp; 287 } 288 289 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2); 290 if (cur_tp2 < mr->cur_tp) { 291 mi->max_tp_rate2 = mg->max_tp_rate2; 292 cur_tp2 = mr->cur_tp; 293 } 294 } 295 296 mi->stats_update = jiffies; 297 } 298 299 static bool 300 minstrel_ht_txstat_valid(struct ieee80211_tx_rate *rate) 301 { 302 if (rate->idx < 0) 303 return false; 304 305 if (!rate->count) 306 return false; 307 308 return !!(rate->flags & IEEE80211_TX_RC_MCS); 309 } 310 311 static void 312 minstrel_next_sample_idx(struct minstrel_ht_sta *mi) 313 { 314 struct minstrel_mcs_group_data *mg; 315 316 for (;;) { 317 mi->sample_group++; 318 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups); 319 mg = &mi->groups[mi->sample_group]; 320 321 if (!mg->supported) 322 continue; 323 324 if (++mg->index >= MCS_GROUP_RATES) { 325 mg->index = 0; 326 if (++mg->column >= ARRAY_SIZE(sample_table)) 327 mg->column = 0; 328 } 329 break; 330 } 331 } 332 333 static void 334 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx, 335 bool primary) 336 { 337 int group, orig_group; 338 339 orig_group = group = *idx / MCS_GROUP_RATES; 340 while (group > 0) { 341 group--; 342 343 if (!mi->groups[group].supported) 344 continue; 345 346 if (minstrel_mcs_groups[group].streams > 347 minstrel_mcs_groups[orig_group].streams) 348 continue; 349 350 if (primary) 351 *idx = mi->groups[group].max_tp_rate; 352 else 353 *idx = mi->groups[group].max_tp_rate2; 354 break; 355 } 356 } 357 358 static void 359 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb) 360 { 361 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 362 struct sta_info *sta = container_of(pubsta, struct sta_info, sta); 363 u16 tid; 364 365 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control))) 366 return; 367 368 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE))) 369 return; 370 371 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; 372 if (likely(sta->ampdu_mlme.tid_tx[tid])) 373 return; 374 375 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO) 376 return; 377 378 ieee80211_start_tx_ba_session(pubsta, tid, 5000); 379 } 380 381 static void 382 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, 383 struct ieee80211_sta *sta, void *priv_sta, 384 struct sk_buff *skb) 385 { 386 struct minstrel_ht_sta_priv *msp = priv_sta; 387 struct minstrel_ht_sta *mi = &msp->ht; 388 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 389 struct ieee80211_tx_rate *ar = info->status.rates; 390 struct minstrel_rate_stats *rate, *rate2; 391 struct minstrel_priv *mp = priv; 392 bool last; 393 int group; 394 int i; 395 396 if (!msp->is_ht) 397 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb); 398 399 /* This packet was aggregated but doesn't carry status info */ 400 if ((info->flags & IEEE80211_TX_CTL_AMPDU) && 401 !(info->flags & IEEE80211_TX_STAT_AMPDU)) 402 return; 403 404 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) { 405 info->status.ampdu_ack_len = 406 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0); 407 info->status.ampdu_len = 1; 408 } 409 410 mi->ampdu_packets++; 411 mi->ampdu_len += info->status.ampdu_len; 412 413 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) { 414 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len); 415 mi->sample_tries = 2; 416 mi->sample_count--; 417 } 418 419 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) 420 mi->sample_packets += info->status.ampdu_len; 421 422 last = !minstrel_ht_txstat_valid(&ar[0]); 423 for (i = 0; !last; i++) { 424 last = (i == IEEE80211_TX_MAX_RATES - 1) || 425 !minstrel_ht_txstat_valid(&ar[i + 1]); 426 427 group = minstrel_ht_get_group_idx(&ar[i]); 428 rate = &mi->groups[group].rates[ar[i].idx % 8]; 429 430 if (last) 431 rate->success += info->status.ampdu_ack_len; 432 433 rate->attempts += ar[i].count * info->status.ampdu_len; 434 } 435 436 /* 437 * check for sudden death of spatial multiplexing, 438 * downgrade to a lower number of streams if necessary. 439 */ 440 rate = minstrel_get_ratestats(mi, mi->max_tp_rate); 441 if (rate->attempts > 30 && 442 MINSTREL_FRAC(rate->success, rate->attempts) < 443 MINSTREL_FRAC(20, 100)) 444 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true); 445 446 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2); 447 if (rate2->attempts > 30 && 448 MINSTREL_FRAC(rate2->success, rate2->attempts) < 449 MINSTREL_FRAC(20, 100)) 450 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false); 451 452 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) { 453 minstrel_ht_update_stats(mp, mi); 454 if (!(info->flags & IEEE80211_TX_CTL_AMPDU)) 455 minstrel_aggr_check(sta, skb); 456 } 457 } 458 459 static void 460 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 461 int index) 462 { 463 struct minstrel_rate_stats *mr; 464 const struct mcs_group *group; 465 unsigned int tx_time, tx_time_rtscts, tx_time_data; 466 unsigned int cw = mp->cw_min; 467 unsigned int ctime = 0; 468 unsigned int t_slot = 9; /* FIXME */ 469 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len); 470 471 mr = minstrel_get_ratestats(mi, index); 472 if (mr->probability < MINSTREL_FRAC(1, 10)) { 473 mr->retry_count = 1; 474 mr->retry_count_rtscts = 1; 475 return; 476 } 477 478 mr->retry_count = 2; 479 mr->retry_count_rtscts = 2; 480 mr->retry_updated = true; 481 482 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 483 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len; 484 485 /* Contention time for first 2 tries */ 486 ctime = (t_slot * cw) >> 1; 487 cw = min((cw << 1) | 1, mp->cw_max); 488 ctime += (t_slot * cw) >> 1; 489 cw = min((cw << 1) | 1, mp->cw_max); 490 491 /* Total TX time for data and Contention after first 2 tries */ 492 tx_time = ctime + 2 * (mi->overhead + tx_time_data); 493 tx_time_rtscts = ctime + 2 * (mi->overhead_rtscts + tx_time_data); 494 495 /* See how many more tries we can fit inside segment size */ 496 do { 497 /* Contention time for this try */ 498 ctime = (t_slot * cw) >> 1; 499 cw = min((cw << 1) | 1, mp->cw_max); 500 501 /* Total TX time after this try */ 502 tx_time += ctime + mi->overhead + tx_time_data; 503 tx_time_rtscts += ctime + mi->overhead_rtscts + tx_time_data; 504 505 if (tx_time_rtscts < mp->segment_size) 506 mr->retry_count_rtscts++; 507 } while ((tx_time < mp->segment_size) && 508 (++mr->retry_count < mp->max_retry)); 509 } 510 511 512 static void 513 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 514 struct ieee80211_tx_rate *rate, int index, 515 bool sample, bool rtscts) 516 { 517 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 518 struct minstrel_rate_stats *mr; 519 520 mr = minstrel_get_ratestats(mi, index); 521 if (!mr->retry_updated) 522 minstrel_calc_retransmit(mp, mi, index); 523 524 if (sample) 525 rate->count = 1; 526 else if (mr->probability < MINSTREL_FRAC(20, 100)) 527 rate->count = 2; 528 else if (rtscts) 529 rate->count = mr->retry_count_rtscts; 530 else 531 rate->count = mr->retry_count; 532 533 rate->flags = IEEE80211_TX_RC_MCS | group->flags; 534 if (rtscts) 535 rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS; 536 rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES; 537 } 538 539 static inline int 540 minstrel_get_duration(int index) 541 { 542 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 543 return group->duration[index % MCS_GROUP_RATES]; 544 } 545 546 static int 547 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 548 { 549 struct minstrel_rate_stats *mr; 550 struct minstrel_mcs_group_data *mg; 551 int sample_idx = 0; 552 553 if (mi->sample_wait > 0) { 554 mi->sample_wait--; 555 return -1; 556 } 557 558 if (!mi->sample_tries) 559 return -1; 560 561 mi->sample_tries--; 562 mg = &mi->groups[mi->sample_group]; 563 sample_idx = sample_table[mg->column][mg->index]; 564 mr = &mg->rates[sample_idx]; 565 sample_idx += mi->sample_group * MCS_GROUP_RATES; 566 minstrel_next_sample_idx(mi); 567 568 /* 569 * Sampling might add some overhead (RTS, no aggregation) 570 * to the frame. Hence, don't use sampling for the currently 571 * used max TP rate. 572 */ 573 if (sample_idx == mi->max_tp_rate) 574 return -1; 575 /* 576 * When not using MRR, do not sample if the probability is already 577 * higher than 95% to avoid wasting airtime 578 */ 579 if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100))) 580 return -1; 581 582 /* 583 * Make sure that lower rates get sampled only occasionally, 584 * if the link is working perfectly. 585 */ 586 if (minstrel_get_duration(sample_idx) > 587 minstrel_get_duration(mi->max_tp_rate)) { 588 if (mr->sample_skipped < 20) 589 return -1; 590 591 if (mi->sample_slow++ > 2) 592 return -1; 593 } 594 595 return sample_idx; 596 } 597 598 static void 599 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, 600 struct ieee80211_tx_rate_control *txrc) 601 { 602 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); 603 struct ieee80211_tx_rate *ar = info->status.rates; 604 struct minstrel_ht_sta_priv *msp = priv_sta; 605 struct minstrel_ht_sta *mi = &msp->ht; 606 struct minstrel_priv *mp = priv; 607 int sample_idx; 608 bool sample = false; 609 610 if (rate_control_send_low(sta, priv_sta, txrc)) 611 return; 612 613 if (!msp->is_ht) 614 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc); 615 616 info->flags |= mi->tx_flags; 617 618 /* Don't use EAPOL frames for sampling on non-mrr hw */ 619 if (mp->hw->max_rates == 1 && 620 txrc->skb->protocol == cpu_to_be16(ETH_P_PAE)) 621 sample_idx = -1; 622 else 623 sample_idx = minstrel_get_sample_rate(mp, mi); 624 625 #ifdef CONFIG_MAC80211_DEBUGFS 626 /* use fixed index if set */ 627 if (mp->fixed_rate_idx != -1) { 628 mi->max_tp_rate = mp->fixed_rate_idx; 629 mi->max_tp_rate2 = mp->fixed_rate_idx; 630 mi->max_prob_rate = mp->fixed_rate_idx; 631 sample_idx = -1; 632 } 633 #endif 634 635 if (sample_idx >= 0) { 636 sample = true; 637 minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx, 638 true, false); 639 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; 640 } else { 641 minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate, 642 false, false); 643 } 644 645 if (mp->hw->max_rates >= 3) { 646 /* 647 * At least 3 tx rates supported, use 648 * sample_rate -> max_tp_rate -> max_prob_rate for sampling and 649 * max_tp_rate -> max_tp_rate2 -> max_prob_rate by default. 650 */ 651 if (sample_idx >= 0) 652 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate, 653 false, false); 654 else 655 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2, 656 false, true); 657 658 minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, 659 false, !sample); 660 661 ar[3].count = 0; 662 ar[3].idx = -1; 663 } else if (mp->hw->max_rates == 2) { 664 /* 665 * Only 2 tx rates supported, use 666 * sample_rate -> max_prob_rate for sampling and 667 * max_tp_rate -> max_prob_rate by default. 668 */ 669 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_prob_rate, 670 false, !sample); 671 672 ar[2].count = 0; 673 ar[2].idx = -1; 674 } else { 675 /* Not using MRR, only use the first rate */ 676 ar[1].count = 0; 677 ar[1].idx = -1; 678 } 679 680 mi->total_packets++; 681 682 /* wraparound */ 683 if (mi->total_packets == ~0) { 684 mi->total_packets = 0; 685 mi->sample_packets = 0; 686 } 687 } 688 689 static void 690 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, 691 struct ieee80211_sta *sta, void *priv_sta) 692 { 693 struct minstrel_priv *mp = priv; 694 struct minstrel_ht_sta_priv *msp = priv_sta; 695 struct minstrel_ht_sta *mi = &msp->ht; 696 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs; 697 u16 sta_cap = sta->ht_cap.cap; 698 int n_supported = 0; 699 int ack_dur; 700 int stbc; 701 int i; 702 unsigned int smps; 703 704 /* fall back to the old minstrel for legacy stations */ 705 if (!sta->ht_cap.ht_supported) 706 goto use_legacy; 707 708 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != 709 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS); 710 711 msp->is_ht = true; 712 memset(mi, 0, sizeof(*mi)); 713 mi->stats_update = jiffies; 714 715 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1); 716 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1) + ack_dur; 717 mi->overhead_rtscts = mi->overhead + 2 * ack_dur; 718 719 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1); 720 721 /* When using MRR, sample more on the first attempt, without delay */ 722 if (mp->has_mrr) { 723 mi->sample_count = 16; 724 mi->sample_wait = 0; 725 } else { 726 mi->sample_count = 8; 727 mi->sample_wait = 8; 728 } 729 mi->sample_tries = 4; 730 731 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >> 732 IEEE80211_HT_CAP_RX_STBC_SHIFT; 733 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT; 734 735 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING) 736 mi->tx_flags |= IEEE80211_TX_CTL_LDPC; 737 738 smps = (sta_cap & IEEE80211_HT_CAP_SM_PS) >> 739 IEEE80211_HT_CAP_SM_PS_SHIFT; 740 741 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) { 742 u16 req = 0; 743 744 mi->groups[i].supported = 0; 745 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) { 746 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) 747 req |= IEEE80211_HT_CAP_SGI_40; 748 else 749 req |= IEEE80211_HT_CAP_SGI_20; 750 } 751 752 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) 753 req |= IEEE80211_HT_CAP_SUP_WIDTH_20_40; 754 755 if ((sta_cap & req) != req) 756 continue; 757 758 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */ 759 if (smps == WLAN_HT_CAP_SM_PS_STATIC && 760 minstrel_mcs_groups[i].streams > 1) 761 continue; 762 763 mi->groups[i].supported = 764 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1]; 765 766 if (mi->groups[i].supported) 767 n_supported++; 768 } 769 770 if (!n_supported) 771 goto use_legacy; 772 773 return; 774 775 use_legacy: 776 msp->is_ht = false; 777 memset(&msp->legacy, 0, sizeof(msp->legacy)); 778 msp->legacy.r = msp->ratelist; 779 msp->legacy.sample_table = msp->sample_table; 780 return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy); 781 } 782 783 static void 784 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband, 785 struct ieee80211_sta *sta, void *priv_sta) 786 { 787 minstrel_ht_update_caps(priv, sband, sta, priv_sta); 788 } 789 790 static void 791 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband, 792 struct ieee80211_sta *sta, void *priv_sta, 793 u32 changed) 794 { 795 minstrel_ht_update_caps(priv, sband, sta, priv_sta); 796 } 797 798 static void * 799 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp) 800 { 801 struct ieee80211_supported_band *sband; 802 struct minstrel_ht_sta_priv *msp; 803 struct minstrel_priv *mp = priv; 804 struct ieee80211_hw *hw = mp->hw; 805 int max_rates = 0; 806 int i; 807 808 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 809 sband = hw->wiphy->bands[i]; 810 if (sband && sband->n_bitrates > max_rates) 811 max_rates = sband->n_bitrates; 812 } 813 814 msp = kzalloc(sizeof(*msp), gfp); 815 if (!msp) 816 return NULL; 817 818 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp); 819 if (!msp->ratelist) 820 goto error; 821 822 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp); 823 if (!msp->sample_table) 824 goto error1; 825 826 return msp; 827 828 error1: 829 kfree(msp->ratelist); 830 error: 831 kfree(msp); 832 return NULL; 833 } 834 835 static void 836 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta) 837 { 838 struct minstrel_ht_sta_priv *msp = priv_sta; 839 840 kfree(msp->sample_table); 841 kfree(msp->ratelist); 842 kfree(msp); 843 } 844 845 static void * 846 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) 847 { 848 return mac80211_minstrel.alloc(hw, debugfsdir); 849 } 850 851 static void 852 minstrel_ht_free(void *priv) 853 { 854 mac80211_minstrel.free(priv); 855 } 856 857 static struct rate_control_ops mac80211_minstrel_ht = { 858 .name = "minstrel_ht", 859 .tx_status = minstrel_ht_tx_status, 860 .get_rate = minstrel_ht_get_rate, 861 .rate_init = minstrel_ht_rate_init, 862 .rate_update = minstrel_ht_rate_update, 863 .alloc_sta = minstrel_ht_alloc_sta, 864 .free_sta = minstrel_ht_free_sta, 865 .alloc = minstrel_ht_alloc, 866 .free = minstrel_ht_free, 867 #ifdef CONFIG_MAC80211_DEBUGFS 868 .add_sta_debugfs = minstrel_ht_add_sta_debugfs, 869 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs, 870 #endif 871 }; 872 873 874 static void 875 init_sample_table(void) 876 { 877 int col, i, new_idx; 878 u8 rnd[MCS_GROUP_RATES]; 879 880 memset(sample_table, 0xff, sizeof(sample_table)); 881 for (col = 0; col < SAMPLE_COLUMNS; col++) { 882 for (i = 0; i < MCS_GROUP_RATES; i++) { 883 get_random_bytes(rnd, sizeof(rnd)); 884 new_idx = (i + rnd[i]) % MCS_GROUP_RATES; 885 886 while (sample_table[col][new_idx] != 0xff) 887 new_idx = (new_idx + 1) % MCS_GROUP_RATES; 888 889 sample_table[col][new_idx] = i; 890 } 891 } 892 } 893 894 int __init 895 rc80211_minstrel_ht_init(void) 896 { 897 init_sample_table(); 898 return ieee80211_rate_control_register(&mac80211_minstrel_ht); 899 } 900 901 void 902 rc80211_minstrel_ht_exit(void) 903 { 904 ieee80211_rate_control_unregister(&mac80211_minstrel_ht); 905 } 906