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 = false; 393 int group; 394 int i = 0; 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 for (i = 0; !last; i++) { 423 last = (i == IEEE80211_TX_MAX_RATES - 1) || 424 !minstrel_ht_txstat_valid(&ar[i + 1]); 425 426 if (!minstrel_ht_txstat_valid(&ar[i])) 427 break; 428 429 group = minstrel_ht_get_group_idx(&ar[i]); 430 rate = &mi->groups[group].rates[ar[i].idx % 8]; 431 432 if (last) 433 rate->success += info->status.ampdu_ack_len; 434 435 rate->attempts += ar[i].count * info->status.ampdu_len; 436 } 437 438 /* 439 * check for sudden death of spatial multiplexing, 440 * downgrade to a lower number of streams if necessary. 441 */ 442 rate = minstrel_get_ratestats(mi, mi->max_tp_rate); 443 if (rate->attempts > 30 && 444 MINSTREL_FRAC(rate->success, rate->attempts) < 445 MINSTREL_FRAC(20, 100)) 446 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true); 447 448 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2); 449 if (rate2->attempts > 30 && 450 MINSTREL_FRAC(rate2->success, rate2->attempts) < 451 MINSTREL_FRAC(20, 100)) 452 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false); 453 454 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) { 455 minstrel_ht_update_stats(mp, mi); 456 if (!(info->flags & IEEE80211_TX_CTL_AMPDU)) 457 minstrel_aggr_check(sta, skb); 458 } 459 } 460 461 static void 462 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 463 int index) 464 { 465 struct minstrel_rate_stats *mr; 466 const struct mcs_group *group; 467 unsigned int tx_time, tx_time_rtscts, tx_time_data; 468 unsigned int cw = mp->cw_min; 469 unsigned int ctime = 0; 470 unsigned int t_slot = 9; /* FIXME */ 471 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len); 472 473 mr = minstrel_get_ratestats(mi, index); 474 if (mr->probability < MINSTREL_FRAC(1, 10)) { 475 mr->retry_count = 1; 476 mr->retry_count_rtscts = 1; 477 return; 478 } 479 480 mr->retry_count = 2; 481 mr->retry_count_rtscts = 2; 482 mr->retry_updated = true; 483 484 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 485 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len; 486 487 /* Contention time for first 2 tries */ 488 ctime = (t_slot * cw) >> 1; 489 cw = min((cw << 1) | 1, mp->cw_max); 490 ctime += (t_slot * cw) >> 1; 491 cw = min((cw << 1) | 1, mp->cw_max); 492 493 /* Total TX time for data and Contention after first 2 tries */ 494 tx_time = ctime + 2 * (mi->overhead + tx_time_data); 495 tx_time_rtscts = ctime + 2 * (mi->overhead_rtscts + tx_time_data); 496 497 /* See how many more tries we can fit inside segment size */ 498 do { 499 /* Contention time for this try */ 500 ctime = (t_slot * cw) >> 1; 501 cw = min((cw << 1) | 1, mp->cw_max); 502 503 /* Total TX time after this try */ 504 tx_time += ctime + mi->overhead + tx_time_data; 505 tx_time_rtscts += ctime + mi->overhead_rtscts + tx_time_data; 506 507 if (tx_time_rtscts < mp->segment_size) 508 mr->retry_count_rtscts++; 509 } while ((tx_time < mp->segment_size) && 510 (++mr->retry_count < mp->max_retry)); 511 } 512 513 514 static void 515 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 516 struct ieee80211_tx_rate *rate, int index, 517 bool sample, bool rtscts) 518 { 519 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 520 struct minstrel_rate_stats *mr; 521 522 mr = minstrel_get_ratestats(mi, index); 523 if (!mr->retry_updated) 524 minstrel_calc_retransmit(mp, mi, index); 525 526 if (sample) 527 rate->count = 1; 528 else if (mr->probability < MINSTREL_FRAC(20, 100)) 529 rate->count = 2; 530 else if (rtscts) 531 rate->count = mr->retry_count_rtscts; 532 else 533 rate->count = mr->retry_count; 534 535 rate->flags = IEEE80211_TX_RC_MCS | group->flags; 536 if (rtscts) 537 rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS; 538 rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES; 539 } 540 541 static inline int 542 minstrel_get_duration(int index) 543 { 544 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 545 return group->duration[index % MCS_GROUP_RATES]; 546 } 547 548 static int 549 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 550 { 551 struct minstrel_rate_stats *mr; 552 struct minstrel_mcs_group_data *mg; 553 int sample_idx = 0; 554 555 if (mi->sample_wait > 0) { 556 mi->sample_wait--; 557 return -1; 558 } 559 560 if (!mi->sample_tries) 561 return -1; 562 563 mi->sample_tries--; 564 mg = &mi->groups[mi->sample_group]; 565 sample_idx = sample_table[mg->column][mg->index]; 566 mr = &mg->rates[sample_idx]; 567 sample_idx += mi->sample_group * MCS_GROUP_RATES; 568 minstrel_next_sample_idx(mi); 569 570 /* 571 * When not using MRR, do not sample if the probability is already 572 * higher than 95% to avoid wasting airtime 573 */ 574 if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100))) 575 return -1; 576 577 /* 578 * Make sure that lower rates get sampled only occasionally, 579 * if the link is working perfectly. 580 */ 581 if (minstrel_get_duration(sample_idx) > 582 minstrel_get_duration(mi->max_tp_rate)) { 583 if (mr->sample_skipped < 20) 584 return -1; 585 586 if (mi->sample_slow++ > 2) 587 return -1; 588 } 589 590 return sample_idx; 591 } 592 593 static void 594 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, 595 struct ieee80211_tx_rate_control *txrc) 596 { 597 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); 598 struct ieee80211_tx_rate *ar = info->status.rates; 599 struct minstrel_ht_sta_priv *msp = priv_sta; 600 struct minstrel_ht_sta *mi = &msp->ht; 601 struct minstrel_priv *mp = priv; 602 int sample_idx; 603 bool sample = false; 604 605 if (rate_control_send_low(sta, priv_sta, txrc)) 606 return; 607 608 if (!msp->is_ht) 609 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc); 610 611 info->flags |= mi->tx_flags; 612 613 /* Don't use EAPOL frames for sampling on non-mrr hw */ 614 if (mp->hw->max_rates == 1 && 615 txrc->skb->protocol == cpu_to_be16(ETH_P_PAE)) 616 sample_idx = -1; 617 else 618 sample_idx = minstrel_get_sample_rate(mp, mi); 619 620 #ifdef CONFIG_MAC80211_DEBUGFS 621 /* use fixed index if set */ 622 if (mp->fixed_rate_idx != -1) 623 sample_idx = mp->fixed_rate_idx; 624 #endif 625 626 if (sample_idx >= 0) { 627 sample = true; 628 minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx, 629 true, false); 630 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; 631 } else { 632 minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate, 633 false, false); 634 } 635 636 if (mp->hw->max_rates >= 3) { 637 /* 638 * At least 3 tx rates supported, use 639 * sample_rate -> max_tp_rate -> max_prob_rate for sampling and 640 * max_tp_rate -> max_tp_rate2 -> max_prob_rate by default. 641 */ 642 if (sample_idx >= 0) 643 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate, 644 false, false); 645 else 646 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2, 647 false, true); 648 649 minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, 650 false, !sample); 651 652 ar[3].count = 0; 653 ar[3].idx = -1; 654 } else if (mp->hw->max_rates == 2) { 655 /* 656 * Only 2 tx rates supported, use 657 * sample_rate -> max_prob_rate for sampling and 658 * max_tp_rate -> max_prob_rate by default. 659 */ 660 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_prob_rate, 661 false, !sample); 662 663 ar[2].count = 0; 664 ar[2].idx = -1; 665 } else { 666 /* Not using MRR, only use the first rate */ 667 ar[1].count = 0; 668 ar[1].idx = -1; 669 } 670 671 mi->total_packets++; 672 673 /* wraparound */ 674 if (mi->total_packets == ~0) { 675 mi->total_packets = 0; 676 mi->sample_packets = 0; 677 } 678 } 679 680 static void 681 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, 682 struct ieee80211_sta *sta, void *priv_sta, 683 enum nl80211_channel_type oper_chan_type) 684 { 685 struct minstrel_priv *mp = priv; 686 struct minstrel_ht_sta_priv *msp = priv_sta; 687 struct minstrel_ht_sta *mi = &msp->ht; 688 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs; 689 struct ieee80211_local *local = hw_to_local(mp->hw); 690 u16 sta_cap = sta->ht_cap.cap; 691 int n_supported = 0; 692 int ack_dur; 693 int stbc; 694 int i; 695 696 /* fall back to the old minstrel for legacy stations */ 697 if (!sta->ht_cap.ht_supported) 698 goto use_legacy; 699 700 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != 701 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS); 702 703 msp->is_ht = true; 704 memset(mi, 0, sizeof(*mi)); 705 mi->stats_update = jiffies; 706 707 ack_dur = ieee80211_frame_duration(local, 10, 60, 1, 1); 708 mi->overhead = ieee80211_frame_duration(local, 0, 60, 1, 1) + ack_dur; 709 mi->overhead_rtscts = mi->overhead + 2 * ack_dur; 710 711 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1); 712 713 /* When using MRR, sample more on the first attempt, without delay */ 714 if (mp->has_mrr) { 715 mi->sample_count = 16; 716 mi->sample_wait = 0; 717 } else { 718 mi->sample_count = 8; 719 mi->sample_wait = 8; 720 } 721 mi->sample_tries = 4; 722 723 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >> 724 IEEE80211_HT_CAP_RX_STBC_SHIFT; 725 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT; 726 727 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING) 728 mi->tx_flags |= IEEE80211_TX_CTL_LDPC; 729 730 if (oper_chan_type != NL80211_CHAN_HT40MINUS && 731 oper_chan_type != NL80211_CHAN_HT40PLUS) 732 sta_cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40; 733 734 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) { 735 u16 req = 0; 736 737 mi->groups[i].supported = 0; 738 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) { 739 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) 740 req |= IEEE80211_HT_CAP_SGI_40; 741 else 742 req |= IEEE80211_HT_CAP_SGI_20; 743 } 744 745 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) 746 req |= IEEE80211_HT_CAP_SUP_WIDTH_20_40; 747 748 if ((sta_cap & req) != req) 749 continue; 750 751 mi->groups[i].supported = 752 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1]; 753 754 if (mi->groups[i].supported) 755 n_supported++; 756 } 757 758 if (!n_supported) 759 goto use_legacy; 760 761 return; 762 763 use_legacy: 764 msp->is_ht = false; 765 memset(&msp->legacy, 0, sizeof(msp->legacy)); 766 msp->legacy.r = msp->ratelist; 767 msp->legacy.sample_table = msp->sample_table; 768 return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy); 769 } 770 771 static void 772 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband, 773 struct ieee80211_sta *sta, void *priv_sta) 774 { 775 struct minstrel_priv *mp = priv; 776 777 minstrel_ht_update_caps(priv, sband, sta, priv_sta, mp->hw->conf.channel_type); 778 } 779 780 static void 781 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband, 782 struct ieee80211_sta *sta, void *priv_sta, 783 u32 changed, enum nl80211_channel_type oper_chan_type) 784 { 785 minstrel_ht_update_caps(priv, sband, sta, priv_sta, oper_chan_type); 786 } 787 788 static void * 789 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp) 790 { 791 struct ieee80211_supported_band *sband; 792 struct minstrel_ht_sta_priv *msp; 793 struct minstrel_priv *mp = priv; 794 struct ieee80211_hw *hw = mp->hw; 795 int max_rates = 0; 796 int i; 797 798 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 799 sband = hw->wiphy->bands[i]; 800 if (sband && sband->n_bitrates > max_rates) 801 max_rates = sband->n_bitrates; 802 } 803 804 msp = kzalloc(sizeof(struct minstrel_ht_sta), gfp); 805 if (!msp) 806 return NULL; 807 808 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp); 809 if (!msp->ratelist) 810 goto error; 811 812 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp); 813 if (!msp->sample_table) 814 goto error1; 815 816 return msp; 817 818 error1: 819 kfree(msp->ratelist); 820 error: 821 kfree(msp); 822 return NULL; 823 } 824 825 static void 826 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta) 827 { 828 struct minstrel_ht_sta_priv *msp = priv_sta; 829 830 kfree(msp->sample_table); 831 kfree(msp->ratelist); 832 kfree(msp); 833 } 834 835 static void * 836 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) 837 { 838 return mac80211_minstrel.alloc(hw, debugfsdir); 839 } 840 841 static void 842 minstrel_ht_free(void *priv) 843 { 844 mac80211_minstrel.free(priv); 845 } 846 847 static struct rate_control_ops mac80211_minstrel_ht = { 848 .name = "minstrel_ht", 849 .tx_status = minstrel_ht_tx_status, 850 .get_rate = minstrel_ht_get_rate, 851 .rate_init = minstrel_ht_rate_init, 852 .rate_update = minstrel_ht_rate_update, 853 .alloc_sta = minstrel_ht_alloc_sta, 854 .free_sta = minstrel_ht_free_sta, 855 .alloc = minstrel_ht_alloc, 856 .free = minstrel_ht_free, 857 #ifdef CONFIG_MAC80211_DEBUGFS 858 .add_sta_debugfs = minstrel_ht_add_sta_debugfs, 859 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs, 860 #endif 861 }; 862 863 864 static void 865 init_sample_table(void) 866 { 867 int col, i, new_idx; 868 u8 rnd[MCS_GROUP_RATES]; 869 870 memset(sample_table, 0xff, sizeof(sample_table)); 871 for (col = 0; col < SAMPLE_COLUMNS; col++) { 872 for (i = 0; i < MCS_GROUP_RATES; i++) { 873 get_random_bytes(rnd, sizeof(rnd)); 874 new_idx = (i + rnd[i]) % MCS_GROUP_RATES; 875 876 while (sample_table[col][new_idx] != 0xff) 877 new_idx = (new_idx + 1) % MCS_GROUP_RATES; 878 879 sample_table[col][new_idx] = i; 880 } 881 } 882 } 883 884 int __init 885 rc80211_minstrel_ht_init(void) 886 { 887 init_sample_table(); 888 return ieee80211_rate_control_register(&mac80211_minstrel_ht); 889 } 890 891 void 892 rc80211_minstrel_ht_exit(void) 893 { 894 ieee80211_rate_control_unregister(&mac80211_minstrel_ht); 895 } 896