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 /* MCS rate information for an MCS group */ 40 #define MCS_GROUP(_streams, _sgi, _ht40) { \ 41 .streams = _streams, \ 42 .flags = \ 43 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \ 44 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \ 45 .duration = { \ 46 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \ 47 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \ 48 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \ 49 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \ 50 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \ 51 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \ 52 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \ 53 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \ 54 } \ 55 } 56 57 /* 58 * To enable sufficiently targeted rate sampling, MCS rates are divided into 59 * groups, based on the number of streams and flags (HT40, SGI) that they 60 * use. 61 */ 62 const struct mcs_group minstrel_mcs_groups[] = { 63 MCS_GROUP(1, 0, 0), 64 MCS_GROUP(2, 0, 0), 65 #if MINSTREL_MAX_STREAMS >= 3 66 MCS_GROUP(3, 0, 0), 67 #endif 68 69 MCS_GROUP(1, 1, 0), 70 MCS_GROUP(2, 1, 0), 71 #if MINSTREL_MAX_STREAMS >= 3 72 MCS_GROUP(3, 1, 0), 73 #endif 74 75 MCS_GROUP(1, 0, 1), 76 MCS_GROUP(2, 0, 1), 77 #if MINSTREL_MAX_STREAMS >= 3 78 MCS_GROUP(3, 0, 1), 79 #endif 80 81 MCS_GROUP(1, 1, 1), 82 MCS_GROUP(2, 1, 1), 83 #if MINSTREL_MAX_STREAMS >= 3 84 MCS_GROUP(3, 1, 1), 85 #endif 86 }; 87 88 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES]; 89 90 /* 91 * Perform EWMA (Exponentially Weighted Moving Average) calculation 92 */ 93 static int 94 minstrel_ewma(int old, int new, int weight) 95 { 96 return (new * (100 - weight) + old * weight) / 100; 97 } 98 99 /* 100 * Look up an MCS group index based on mac80211 rate information 101 */ 102 static int 103 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate) 104 { 105 int streams = (rate->idx / MCS_GROUP_RATES) + 1; 106 u32 flags = IEEE80211_TX_RC_SHORT_GI | IEEE80211_TX_RC_40_MHZ_WIDTH; 107 int i; 108 109 for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) { 110 if (minstrel_mcs_groups[i].streams != streams) 111 continue; 112 if (minstrel_mcs_groups[i].flags != (rate->flags & flags)) 113 continue; 114 115 return i; 116 } 117 118 WARN_ON(1); 119 return 0; 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_priv *mp, 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_priv *mp, struct minstrel_ht_sta *mi, 160 int group, int rate) 161 { 162 struct minstrel_rate_stats *mr; 163 unsigned int usecs; 164 165 mr = &mi->groups[group].rates[rate]; 166 167 if (mr->probability < MINSTREL_FRAC(1, 10)) { 168 mr->cur_tp = 0; 169 return; 170 } 171 172 usecs = mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len); 173 usecs += minstrel_mcs_groups[group].duration[rate]; 174 mr->cur_tp = MINSTREL_TRUNC((1000000 / usecs) * mr->probability); 175 } 176 177 /* 178 * Update rate statistics and select new primary rates 179 * 180 * Rules for rate selection: 181 * - max_prob_rate must use only one stream, as a tradeoff between delivery 182 * probability and throughput during strong fluctuations 183 * - as long as the max prob rate has a probability of more than 3/4, pick 184 * higher throughput rates, even if the probablity is a bit lower 185 */ 186 static void 187 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 188 { 189 struct minstrel_mcs_group_data *mg; 190 struct minstrel_rate_stats *mr; 191 int cur_prob, cur_prob_tp, cur_tp, cur_tp2; 192 int group, i, index; 193 194 if (mi->ampdu_packets > 0) { 195 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len, 196 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL); 197 mi->ampdu_len = 0; 198 mi->ampdu_packets = 0; 199 } 200 201 mi->sample_slow = 0; 202 mi->sample_count = 0; 203 mi->max_tp_rate = 0; 204 mi->max_tp_rate2 = 0; 205 mi->max_prob_rate = 0; 206 207 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { 208 cur_prob = 0; 209 cur_prob_tp = 0; 210 cur_tp = 0; 211 cur_tp2 = 0; 212 213 mg = &mi->groups[group]; 214 if (!mg->supported) 215 continue; 216 217 mg->max_tp_rate = 0; 218 mg->max_tp_rate2 = 0; 219 mg->max_prob_rate = 0; 220 mi->sample_count++; 221 222 for (i = 0; i < MCS_GROUP_RATES; i++) { 223 if (!(mg->supported & BIT(i))) 224 continue; 225 226 mr = &mg->rates[i]; 227 mr->retry_updated = false; 228 index = MCS_GROUP_RATES * group + i; 229 minstrel_calc_rate_ewma(mp, mr); 230 minstrel_ht_calc_tp(mp, mi, group, i); 231 232 if (!mr->cur_tp) 233 continue; 234 235 /* ignore the lowest rate of each single-stream group */ 236 if (!i && minstrel_mcs_groups[group].streams == 1) 237 continue; 238 239 if ((mr->cur_tp > cur_prob_tp && mr->probability > 240 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) { 241 mg->max_prob_rate = index; 242 cur_prob = mr->probability; 243 cur_prob_tp = mr->cur_tp; 244 } 245 246 if (mr->cur_tp > cur_tp) { 247 swap(index, mg->max_tp_rate); 248 cur_tp = mr->cur_tp; 249 mr = minstrel_get_ratestats(mi, index); 250 } 251 252 if (index >= mg->max_tp_rate) 253 continue; 254 255 if (mr->cur_tp > cur_tp2) { 256 mg->max_tp_rate2 = index; 257 cur_tp2 = mr->cur_tp; 258 } 259 } 260 } 261 262 /* try to sample up to half of the available rates during each interval */ 263 mi->sample_count *= 4; 264 265 cur_prob = 0; 266 cur_prob_tp = 0; 267 cur_tp = 0; 268 cur_tp2 = 0; 269 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { 270 mg = &mi->groups[group]; 271 if (!mg->supported) 272 continue; 273 274 mr = minstrel_get_ratestats(mi, mg->max_prob_rate); 275 if (cur_prob_tp < mr->cur_tp && 276 minstrel_mcs_groups[group].streams == 1) { 277 mi->max_prob_rate = mg->max_prob_rate; 278 cur_prob = mr->cur_prob; 279 cur_prob_tp = mr->cur_tp; 280 } 281 282 mr = minstrel_get_ratestats(mi, mg->max_tp_rate); 283 if (cur_tp < mr->cur_tp) { 284 mi->max_tp_rate = mg->max_tp_rate; 285 cur_tp = mr->cur_tp; 286 } 287 288 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2); 289 if (cur_tp2 < mr->cur_tp) { 290 mi->max_tp_rate2 = mg->max_tp_rate2; 291 cur_tp2 = mr->cur_tp; 292 } 293 } 294 295 mi->stats_update = jiffies; 296 } 297 298 static bool 299 minstrel_ht_txstat_valid(struct ieee80211_tx_rate *rate) 300 { 301 if (!rate->count) 302 return false; 303 304 if (rate->idx < 0) 305 return false; 306 307 return !!(rate->flags & IEEE80211_TX_RC_MCS); 308 } 309 310 static void 311 minstrel_next_sample_idx(struct minstrel_ht_sta *mi) 312 { 313 struct minstrel_mcs_group_data *mg; 314 315 for (;;) { 316 mi->sample_group++; 317 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups); 318 mg = &mi->groups[mi->sample_group]; 319 320 if (!mg->supported) 321 continue; 322 323 if (++mg->index >= MCS_GROUP_RATES) { 324 mg->index = 0; 325 if (++mg->column >= ARRAY_SIZE(sample_table)) 326 mg->column = 0; 327 } 328 break; 329 } 330 } 331 332 static void 333 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx, 334 bool primary) 335 { 336 int group, orig_group; 337 338 orig_group = group = *idx / MCS_GROUP_RATES; 339 while (group > 0) { 340 group--; 341 342 if (!mi->groups[group].supported) 343 continue; 344 345 if (minstrel_mcs_groups[group].streams > 346 minstrel_mcs_groups[orig_group].streams) 347 continue; 348 349 if (primary) 350 *idx = mi->groups[group].max_tp_rate; 351 else 352 *idx = mi->groups[group].max_tp_rate2; 353 break; 354 } 355 } 356 357 static void 358 minstrel_aggr_check(struct minstrel_priv *mp, struct ieee80211_sta *pubsta, struct sk_buff *skb) 359 { 360 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 361 struct sta_info *sta = container_of(pubsta, struct sta_info, sta); 362 u16 tid; 363 364 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control))) 365 return; 366 367 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE))) 368 return; 369 370 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; 371 if (likely(sta->ampdu_mlme.tid_tx[tid])) 372 return; 373 374 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO) 375 return; 376 377 ieee80211_start_tx_ba_session(pubsta, tid, 5000); 378 } 379 380 static void 381 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, 382 struct ieee80211_sta *sta, void *priv_sta, 383 struct sk_buff *skb) 384 { 385 struct minstrel_ht_sta_priv *msp = priv_sta; 386 struct minstrel_ht_sta *mi = &msp->ht; 387 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 388 struct ieee80211_tx_rate *ar = info->status.rates; 389 struct minstrel_rate_stats *rate, *rate2; 390 struct minstrel_priv *mp = priv; 391 bool last = false; 392 int group; 393 int i = 0; 394 395 if (!msp->is_ht) 396 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb); 397 398 /* This packet was aggregated but doesn't carry status info */ 399 if ((info->flags & IEEE80211_TX_CTL_AMPDU) && 400 !(info->flags & IEEE80211_TX_STAT_AMPDU)) 401 return; 402 403 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) { 404 info->status.ampdu_ack_len = 405 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0); 406 info->status.ampdu_len = 1; 407 } 408 409 mi->ampdu_packets++; 410 mi->ampdu_len += info->status.ampdu_len; 411 412 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) { 413 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len); 414 mi->sample_tries = 2; 415 mi->sample_count--; 416 } 417 418 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) 419 mi->sample_packets += info->status.ampdu_len; 420 421 for (i = 0; !last; i++) { 422 last = (i == IEEE80211_TX_MAX_RATES - 1) || 423 !minstrel_ht_txstat_valid(&ar[i + 1]); 424 425 if (!minstrel_ht_txstat_valid(&ar[i])) 426 break; 427 428 group = minstrel_ht_get_group_idx(&ar[i]); 429 rate = &mi->groups[group].rates[ar[i].idx % 8]; 430 431 if (last) 432 rate->success += info->status.ampdu_ack_len; 433 434 rate->attempts += ar[i].count * info->status.ampdu_len; 435 } 436 437 /* 438 * check for sudden death of spatial multiplexing, 439 * downgrade to a lower number of streams if necessary. 440 */ 441 rate = minstrel_get_ratestats(mi, mi->max_tp_rate); 442 if (rate->attempts > 30 && 443 MINSTREL_FRAC(rate->success, rate->attempts) < 444 MINSTREL_FRAC(20, 100)) 445 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true); 446 447 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2); 448 if (rate2->attempts > 30 && 449 MINSTREL_FRAC(rate2->success, rate2->attempts) < 450 MINSTREL_FRAC(20, 100)) 451 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false); 452 453 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) { 454 minstrel_ht_update_stats(mp, mi); 455 minstrel_aggr_check(mp, 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 struct ieee80211_tx_rate_control *txrc, 516 bool sample, bool rtscts) 517 { 518 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 519 struct minstrel_rate_stats *mr; 520 521 mr = minstrel_get_ratestats(mi, index); 522 if (!mr->retry_updated) 523 minstrel_calc_retransmit(mp, mi, index); 524 525 if (sample) 526 rate->count = 1; 527 else if (mr->probability < MINSTREL_FRAC(20, 100)) 528 rate->count = 2; 529 else if (rtscts) 530 rate->count = mr->retry_count_rtscts; 531 else 532 rate->count = mr->retry_count; 533 534 rate->flags = IEEE80211_TX_RC_MCS | group->flags; 535 if (rtscts) 536 rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS; 537 rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES; 538 } 539 540 static inline int 541 minstrel_get_duration(int index) 542 { 543 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 544 return group->duration[index % MCS_GROUP_RATES]; 545 } 546 547 static int 548 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 549 { 550 struct minstrel_rate_stats *mr; 551 struct minstrel_mcs_group_data *mg; 552 int sample_idx = 0; 553 554 if (mi->sample_wait > 0) { 555 mi->sample_wait--; 556 return -1; 557 } 558 559 if (!mi->sample_tries) 560 return -1; 561 562 mi->sample_tries--; 563 mg = &mi->groups[mi->sample_group]; 564 sample_idx = sample_table[mg->column][mg->index]; 565 mr = &mg->rates[sample_idx]; 566 sample_idx += mi->sample_group * MCS_GROUP_RATES; 567 minstrel_next_sample_idx(mi); 568 569 /* 570 * When not using MRR, do not sample if the probability is already 571 * higher than 95% to avoid wasting airtime 572 */ 573 if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100))) 574 return -1; 575 576 /* 577 * Make sure that lower rates get sampled only occasionally, 578 * if the link is working perfectly. 579 */ 580 if (minstrel_get_duration(sample_idx) > 581 minstrel_get_duration(mi->max_tp_rate)) { 582 if (mr->sample_skipped < 20) 583 return -1; 584 585 if (mi->sample_slow++ > 2) 586 return -1; 587 } 588 589 return sample_idx; 590 } 591 592 static void 593 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, 594 struct ieee80211_tx_rate_control *txrc) 595 { 596 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); 597 struct ieee80211_tx_rate *ar = info->status.rates; 598 struct minstrel_ht_sta_priv *msp = priv_sta; 599 struct minstrel_ht_sta *mi = &msp->ht; 600 struct minstrel_priv *mp = priv; 601 int sample_idx; 602 bool sample = false; 603 604 if (rate_control_send_low(sta, priv_sta, txrc)) 605 return; 606 607 if (!msp->is_ht) 608 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc); 609 610 info->flags |= mi->tx_flags; 611 sample_idx = minstrel_get_sample_rate(mp, mi); 612 613 #ifdef CONFIG_MAC80211_DEBUGFS 614 /* use fixed index if set */ 615 if (mp->fixed_rate_idx != -1) 616 sample_idx = mp->fixed_rate_idx; 617 #endif 618 619 if (sample_idx >= 0) { 620 sample = true; 621 minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx, 622 txrc, true, false); 623 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; 624 } else { 625 minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate, 626 txrc, false, false); 627 } 628 629 if (mp->hw->max_rates >= 3) { 630 /* 631 * At least 3 tx rates supported, use 632 * sample_rate -> max_tp_rate -> max_prob_rate for sampling and 633 * max_tp_rate -> max_tp_rate2 -> max_prob_rate by default. 634 */ 635 if (sample_idx >= 0) 636 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate, 637 txrc, false, false); 638 else 639 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2, 640 txrc, false, true); 641 642 minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, 643 txrc, false, !sample); 644 645 ar[3].count = 0; 646 ar[3].idx = -1; 647 } else if (mp->hw->max_rates == 2) { 648 /* 649 * Only 2 tx rates supported, use 650 * sample_rate -> max_prob_rate for sampling and 651 * max_tp_rate -> max_prob_rate by default. 652 */ 653 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_prob_rate, 654 txrc, false, !sample); 655 656 ar[2].count = 0; 657 ar[2].idx = -1; 658 } else { 659 /* Not using MRR, only use the first rate */ 660 ar[1].count = 0; 661 ar[1].idx = -1; 662 } 663 664 mi->total_packets++; 665 666 /* wraparound */ 667 if (mi->total_packets == ~0) { 668 mi->total_packets = 0; 669 mi->sample_packets = 0; 670 } 671 } 672 673 static void 674 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, 675 struct ieee80211_sta *sta, void *priv_sta, 676 enum nl80211_channel_type oper_chan_type) 677 { 678 struct minstrel_priv *mp = priv; 679 struct minstrel_ht_sta_priv *msp = priv_sta; 680 struct minstrel_ht_sta *mi = &msp->ht; 681 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs; 682 struct ieee80211_local *local = hw_to_local(mp->hw); 683 u16 sta_cap = sta->ht_cap.cap; 684 int n_supported = 0; 685 int ack_dur; 686 int stbc; 687 int i; 688 689 /* fall back to the old minstrel for legacy stations */ 690 if (!sta->ht_cap.ht_supported) 691 goto use_legacy; 692 693 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != 694 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS); 695 696 msp->is_ht = true; 697 memset(mi, 0, sizeof(*mi)); 698 mi->stats_update = jiffies; 699 700 ack_dur = ieee80211_frame_duration(local, 10, 60, 1, 1); 701 mi->overhead = ieee80211_frame_duration(local, 0, 60, 1, 1) + ack_dur; 702 mi->overhead_rtscts = mi->overhead + 2 * ack_dur; 703 704 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1); 705 706 /* When using MRR, sample more on the first attempt, without delay */ 707 if (mp->has_mrr) { 708 mi->sample_count = 16; 709 mi->sample_wait = 0; 710 } else { 711 mi->sample_count = 8; 712 mi->sample_wait = 8; 713 } 714 mi->sample_tries = 4; 715 716 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >> 717 IEEE80211_HT_CAP_RX_STBC_SHIFT; 718 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT; 719 720 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING) 721 mi->tx_flags |= IEEE80211_TX_CTL_LDPC; 722 723 if (oper_chan_type != NL80211_CHAN_HT40MINUS && 724 oper_chan_type != NL80211_CHAN_HT40PLUS) 725 sta_cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40; 726 727 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) { 728 u16 req = 0; 729 730 mi->groups[i].supported = 0; 731 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) { 732 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) 733 req |= IEEE80211_HT_CAP_SGI_40; 734 else 735 req |= IEEE80211_HT_CAP_SGI_20; 736 } 737 738 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) 739 req |= IEEE80211_HT_CAP_SUP_WIDTH_20_40; 740 741 if ((sta_cap & req) != req) 742 continue; 743 744 mi->groups[i].supported = 745 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1]; 746 747 if (mi->groups[i].supported) 748 n_supported++; 749 } 750 751 if (!n_supported) 752 goto use_legacy; 753 754 return; 755 756 use_legacy: 757 msp->is_ht = false; 758 memset(&msp->legacy, 0, sizeof(msp->legacy)); 759 msp->legacy.r = msp->ratelist; 760 msp->legacy.sample_table = msp->sample_table; 761 return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy); 762 } 763 764 static void 765 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband, 766 struct ieee80211_sta *sta, void *priv_sta) 767 { 768 struct minstrel_priv *mp = priv; 769 770 minstrel_ht_update_caps(priv, sband, sta, priv_sta, mp->hw->conf.channel_type); 771 } 772 773 static void 774 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband, 775 struct ieee80211_sta *sta, void *priv_sta, 776 u32 changed, enum nl80211_channel_type oper_chan_type) 777 { 778 minstrel_ht_update_caps(priv, sband, sta, priv_sta, oper_chan_type); 779 } 780 781 static void * 782 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp) 783 { 784 struct ieee80211_supported_band *sband; 785 struct minstrel_ht_sta_priv *msp; 786 struct minstrel_priv *mp = priv; 787 struct ieee80211_hw *hw = mp->hw; 788 int max_rates = 0; 789 int i; 790 791 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 792 sband = hw->wiphy->bands[i]; 793 if (sband && sband->n_bitrates > max_rates) 794 max_rates = sband->n_bitrates; 795 } 796 797 msp = kzalloc(sizeof(struct minstrel_ht_sta), gfp); 798 if (!msp) 799 return NULL; 800 801 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp); 802 if (!msp->ratelist) 803 goto error; 804 805 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp); 806 if (!msp->sample_table) 807 goto error1; 808 809 return msp; 810 811 error1: 812 kfree(msp->ratelist); 813 error: 814 kfree(msp); 815 return NULL; 816 } 817 818 static void 819 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta) 820 { 821 struct minstrel_ht_sta_priv *msp = priv_sta; 822 823 kfree(msp->sample_table); 824 kfree(msp->ratelist); 825 kfree(msp); 826 } 827 828 static void * 829 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) 830 { 831 return mac80211_minstrel.alloc(hw, debugfsdir); 832 } 833 834 static void 835 minstrel_ht_free(void *priv) 836 { 837 mac80211_minstrel.free(priv); 838 } 839 840 static struct rate_control_ops mac80211_minstrel_ht = { 841 .name = "minstrel_ht", 842 .tx_status = minstrel_ht_tx_status, 843 .get_rate = minstrel_ht_get_rate, 844 .rate_init = minstrel_ht_rate_init, 845 .rate_update = minstrel_ht_rate_update, 846 .alloc_sta = minstrel_ht_alloc_sta, 847 .free_sta = minstrel_ht_free_sta, 848 .alloc = minstrel_ht_alloc, 849 .free = minstrel_ht_free, 850 #ifdef CONFIG_MAC80211_DEBUGFS 851 .add_sta_debugfs = minstrel_ht_add_sta_debugfs, 852 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs, 853 #endif 854 }; 855 856 857 static void 858 init_sample_table(void) 859 { 860 int col, i, new_idx; 861 u8 rnd[MCS_GROUP_RATES]; 862 863 memset(sample_table, 0xff, sizeof(sample_table)); 864 for (col = 0; col < SAMPLE_COLUMNS; col++) { 865 for (i = 0; i < MCS_GROUP_RATES; i++) { 866 get_random_bytes(rnd, sizeof(rnd)); 867 new_idx = (i + rnd[i]) % MCS_GROUP_RATES; 868 869 while (sample_table[col][new_idx] != 0xff) 870 new_idx = (new_idx + 1) % MCS_GROUP_RATES; 871 872 sample_table[col][new_idx] = i; 873 } 874 } 875 } 876 877 int __init 878 rc80211_minstrel_ht_init(void) 879 { 880 init_sample_table(); 881 return ieee80211_rate_control_register(&mac80211_minstrel_ht); 882 } 883 884 void 885 rc80211_minstrel_ht_exit(void) 886 { 887 ieee80211_rate_control_unregister(&mac80211_minstrel_ht); 888 } 889