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_rate2 = mi->max_tp_rate; 285 cur_tp2 = cur_tp; 286 mi->max_tp_rate = mg->max_tp_rate; 287 cur_tp = mr->cur_tp; 288 } 289 290 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2); 291 if (cur_tp2 < mr->cur_tp) { 292 mi->max_tp_rate2 = mg->max_tp_rate2; 293 cur_tp2 = mr->cur_tp; 294 } 295 } 296 297 mi->stats_update = jiffies; 298 } 299 300 static bool 301 minstrel_ht_txstat_valid(struct ieee80211_tx_rate *rate) 302 { 303 if (!rate->count) 304 return false; 305 306 if (rate->idx < 0) 307 return false; 308 309 return !!(rate->flags & IEEE80211_TX_RC_MCS); 310 } 311 312 static void 313 minstrel_next_sample_idx(struct minstrel_ht_sta *mi) 314 { 315 struct minstrel_mcs_group_data *mg; 316 317 for (;;) { 318 mi->sample_group++; 319 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups); 320 mg = &mi->groups[mi->sample_group]; 321 322 if (!mg->supported) 323 continue; 324 325 if (++mg->index >= MCS_GROUP_RATES) { 326 mg->index = 0; 327 if (++mg->column >= ARRAY_SIZE(sample_table)) 328 mg->column = 0; 329 } 330 break; 331 } 332 } 333 334 static void 335 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx, 336 bool primary) 337 { 338 int group, orig_group; 339 340 orig_group = group = *idx / MCS_GROUP_RATES; 341 while (group > 0) { 342 group--; 343 344 if (!mi->groups[group].supported) 345 continue; 346 347 if (minstrel_mcs_groups[group].streams > 348 minstrel_mcs_groups[orig_group].streams) 349 continue; 350 351 if (primary) 352 *idx = mi->groups[group].max_tp_rate; 353 else 354 *idx = mi->groups[group].max_tp_rate2; 355 break; 356 } 357 } 358 359 static void 360 minstrel_aggr_check(struct minstrel_priv *mp, struct ieee80211_sta *pubsta, struct sk_buff *skb) 361 { 362 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 363 struct sta_info *sta = container_of(pubsta, struct sta_info, sta); 364 u16 tid; 365 366 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control))) 367 return; 368 369 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE))) 370 return; 371 372 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; 373 if (likely(sta->ampdu_mlme.tid_tx[tid])) 374 return; 375 376 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO) 377 return; 378 379 ieee80211_start_tx_ba_session(pubsta, tid, 5000); 380 } 381 382 static void 383 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, 384 struct ieee80211_sta *sta, void *priv_sta, 385 struct sk_buff *skb) 386 { 387 struct minstrel_ht_sta_priv *msp = priv_sta; 388 struct minstrel_ht_sta *mi = &msp->ht; 389 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 390 struct ieee80211_tx_rate *ar = info->status.rates; 391 struct minstrel_rate_stats *rate, *rate2; 392 struct minstrel_priv *mp = priv; 393 bool last = false; 394 int group; 395 int i = 0; 396 397 if (!msp->is_ht) 398 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb); 399 400 /* This packet was aggregated but doesn't carry status info */ 401 if ((info->flags & IEEE80211_TX_CTL_AMPDU) && 402 !(info->flags & IEEE80211_TX_STAT_AMPDU)) 403 return; 404 405 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) { 406 info->status.ampdu_ack_len = 407 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0); 408 info->status.ampdu_len = 1; 409 } 410 411 mi->ampdu_packets++; 412 mi->ampdu_len += info->status.ampdu_len; 413 414 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) { 415 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len); 416 mi->sample_tries = 2; 417 mi->sample_count--; 418 } 419 420 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) 421 mi->sample_packets += info->status.ampdu_len; 422 423 for (i = 0; !last; i++) { 424 last = (i == IEEE80211_TX_MAX_RATES - 1) || 425 !minstrel_ht_txstat_valid(&ar[i + 1]); 426 427 if (!minstrel_ht_txstat_valid(&ar[i])) 428 break; 429 430 group = minstrel_ht_get_group_idx(&ar[i]); 431 rate = &mi->groups[group].rates[ar[i].idx % 8]; 432 433 if (last) 434 rate->success += info->status.ampdu_ack_len; 435 436 rate->attempts += ar[i].count * info->status.ampdu_len; 437 } 438 439 /* 440 * check for sudden death of spatial multiplexing, 441 * downgrade to a lower number of streams if necessary. 442 */ 443 rate = minstrel_get_ratestats(mi, mi->max_tp_rate); 444 if (rate->attempts > 30 && 445 MINSTREL_FRAC(rate->success, rate->attempts) < 446 MINSTREL_FRAC(20, 100)) 447 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true); 448 449 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2); 450 if (rate2->attempts > 30 && 451 MINSTREL_FRAC(rate2->success, rate2->attempts) < 452 MINSTREL_FRAC(20, 100)) 453 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false); 454 455 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) { 456 minstrel_ht_update_stats(mp, mi); 457 if (!(info->flags & IEEE80211_TX_CTL_AMPDU)) 458 minstrel_aggr_check(mp, sta, skb); 459 } 460 } 461 462 static void 463 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 464 int index) 465 { 466 struct minstrel_rate_stats *mr; 467 const struct mcs_group *group; 468 unsigned int tx_time, tx_time_rtscts, tx_time_data; 469 unsigned int cw = mp->cw_min; 470 unsigned int ctime = 0; 471 unsigned int t_slot = 9; /* FIXME */ 472 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len); 473 474 mr = minstrel_get_ratestats(mi, index); 475 if (mr->probability < MINSTREL_FRAC(1, 10)) { 476 mr->retry_count = 1; 477 mr->retry_count_rtscts = 1; 478 return; 479 } 480 481 mr->retry_count = 2; 482 mr->retry_count_rtscts = 2; 483 mr->retry_updated = true; 484 485 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 486 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len; 487 488 /* Contention time for first 2 tries */ 489 ctime = (t_slot * cw) >> 1; 490 cw = min((cw << 1) | 1, mp->cw_max); 491 ctime += (t_slot * cw) >> 1; 492 cw = min((cw << 1) | 1, mp->cw_max); 493 494 /* Total TX time for data and Contention after first 2 tries */ 495 tx_time = ctime + 2 * (mi->overhead + tx_time_data); 496 tx_time_rtscts = ctime + 2 * (mi->overhead_rtscts + tx_time_data); 497 498 /* See how many more tries we can fit inside segment size */ 499 do { 500 /* Contention time for this try */ 501 ctime = (t_slot * cw) >> 1; 502 cw = min((cw << 1) | 1, mp->cw_max); 503 504 /* Total TX time after this try */ 505 tx_time += ctime + mi->overhead + tx_time_data; 506 tx_time_rtscts += ctime + mi->overhead_rtscts + tx_time_data; 507 508 if (tx_time_rtscts < mp->segment_size) 509 mr->retry_count_rtscts++; 510 } while ((tx_time < mp->segment_size) && 511 (++mr->retry_count < mp->max_retry)); 512 } 513 514 515 static void 516 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 517 struct ieee80211_tx_rate *rate, int index, 518 struct ieee80211_tx_rate_control *txrc, 519 bool sample, bool rtscts) 520 { 521 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 522 struct minstrel_rate_stats *mr; 523 524 mr = minstrel_get_ratestats(mi, index); 525 if (!mr->retry_updated) 526 minstrel_calc_retransmit(mp, mi, index); 527 528 if (sample) 529 rate->count = 1; 530 else if (mr->probability < MINSTREL_FRAC(20, 100)) 531 rate->count = 2; 532 else if (rtscts) 533 rate->count = mr->retry_count_rtscts; 534 else 535 rate->count = mr->retry_count; 536 537 rate->flags = IEEE80211_TX_RC_MCS | group->flags; 538 if (rtscts) 539 rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS; 540 rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES; 541 } 542 543 static inline int 544 minstrel_get_duration(int index) 545 { 546 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 547 return group->duration[index % MCS_GROUP_RATES]; 548 } 549 550 static int 551 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 552 { 553 struct minstrel_rate_stats *mr; 554 struct minstrel_mcs_group_data *mg; 555 int sample_idx = 0; 556 557 if (mi->sample_wait > 0) { 558 mi->sample_wait--; 559 return -1; 560 } 561 562 if (!mi->sample_tries) 563 return -1; 564 565 mi->sample_tries--; 566 mg = &mi->groups[mi->sample_group]; 567 sample_idx = sample_table[mg->column][mg->index]; 568 mr = &mg->rates[sample_idx]; 569 sample_idx += mi->sample_group * MCS_GROUP_RATES; 570 minstrel_next_sample_idx(mi); 571 572 /* 573 * When not using MRR, do not sample if the probability is already 574 * higher than 95% to avoid wasting airtime 575 */ 576 if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100))) 577 return -1; 578 579 /* 580 * Make sure that lower rates get sampled only occasionally, 581 * if the link is working perfectly. 582 */ 583 if (minstrel_get_duration(sample_idx) > 584 minstrel_get_duration(mi->max_tp_rate)) { 585 if (mr->sample_skipped < 20) 586 return -1; 587 588 if (mi->sample_slow++ > 2) 589 return -1; 590 } 591 592 return sample_idx; 593 } 594 595 static void 596 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, 597 struct ieee80211_tx_rate_control *txrc) 598 { 599 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); 600 struct ieee80211_tx_rate *ar = info->status.rates; 601 struct minstrel_ht_sta_priv *msp = priv_sta; 602 struct minstrel_ht_sta *mi = &msp->ht; 603 struct minstrel_priv *mp = priv; 604 int sample_idx; 605 bool sample = false; 606 607 if (rate_control_send_low(sta, priv_sta, txrc)) 608 return; 609 610 if (!msp->is_ht) 611 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc); 612 613 info->flags |= mi->tx_flags; 614 615 /* Don't use EAPOL frames for sampling on non-mrr hw */ 616 if (mp->hw->max_rates == 1 && 617 txrc->skb->protocol == cpu_to_be16(ETH_P_PAE)) 618 sample_idx = -1; 619 else 620 sample_idx = minstrel_get_sample_rate(mp, mi); 621 622 #ifdef CONFIG_MAC80211_DEBUGFS 623 /* use fixed index if set */ 624 if (mp->fixed_rate_idx != -1) 625 sample_idx = mp->fixed_rate_idx; 626 #endif 627 628 if (sample_idx >= 0) { 629 sample = true; 630 minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx, 631 txrc, true, false); 632 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; 633 } else { 634 minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate, 635 txrc, false, false); 636 } 637 638 if (mp->hw->max_rates >= 3) { 639 /* 640 * At least 3 tx rates supported, use 641 * sample_rate -> max_tp_rate -> max_prob_rate for sampling and 642 * max_tp_rate -> max_tp_rate2 -> max_prob_rate by default. 643 */ 644 if (sample_idx >= 0) 645 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate, 646 txrc, false, false); 647 else 648 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2, 649 txrc, false, true); 650 651 minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, 652 txrc, false, !sample); 653 654 ar[3].count = 0; 655 ar[3].idx = -1; 656 } else if (mp->hw->max_rates == 2) { 657 /* 658 * Only 2 tx rates supported, use 659 * sample_rate -> max_prob_rate for sampling and 660 * max_tp_rate -> max_prob_rate by default. 661 */ 662 minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_prob_rate, 663 txrc, false, !sample); 664 665 ar[2].count = 0; 666 ar[2].idx = -1; 667 } else { 668 /* Not using MRR, only use the first rate */ 669 ar[1].count = 0; 670 ar[1].idx = -1; 671 } 672 673 mi->total_packets++; 674 675 /* wraparound */ 676 if (mi->total_packets == ~0) { 677 mi->total_packets = 0; 678 mi->sample_packets = 0; 679 } 680 } 681 682 static void 683 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, 684 struct ieee80211_sta *sta, void *priv_sta, 685 enum nl80211_channel_type oper_chan_type) 686 { 687 struct minstrel_priv *mp = priv; 688 struct minstrel_ht_sta_priv *msp = priv_sta; 689 struct minstrel_ht_sta *mi = &msp->ht; 690 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs; 691 struct ieee80211_local *local = hw_to_local(mp->hw); 692 u16 sta_cap = sta->ht_cap.cap; 693 int n_supported = 0; 694 int ack_dur; 695 int stbc; 696 int i; 697 698 /* fall back to the old minstrel for legacy stations */ 699 if (!sta->ht_cap.ht_supported) 700 goto use_legacy; 701 702 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != 703 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS); 704 705 msp->is_ht = true; 706 memset(mi, 0, sizeof(*mi)); 707 mi->stats_update = jiffies; 708 709 ack_dur = ieee80211_frame_duration(local, 10, 60, 1, 1); 710 mi->overhead = ieee80211_frame_duration(local, 0, 60, 1, 1) + ack_dur; 711 mi->overhead_rtscts = mi->overhead + 2 * ack_dur; 712 713 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1); 714 715 /* When using MRR, sample more on the first attempt, without delay */ 716 if (mp->has_mrr) { 717 mi->sample_count = 16; 718 mi->sample_wait = 0; 719 } else { 720 mi->sample_count = 8; 721 mi->sample_wait = 8; 722 } 723 mi->sample_tries = 4; 724 725 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >> 726 IEEE80211_HT_CAP_RX_STBC_SHIFT; 727 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT; 728 729 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING) 730 mi->tx_flags |= IEEE80211_TX_CTL_LDPC; 731 732 if (oper_chan_type != NL80211_CHAN_HT40MINUS && 733 oper_chan_type != NL80211_CHAN_HT40PLUS) 734 sta_cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40; 735 736 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) { 737 u16 req = 0; 738 739 mi->groups[i].supported = 0; 740 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) { 741 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) 742 req |= IEEE80211_HT_CAP_SGI_40; 743 else 744 req |= IEEE80211_HT_CAP_SGI_20; 745 } 746 747 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) 748 req |= IEEE80211_HT_CAP_SUP_WIDTH_20_40; 749 750 if ((sta_cap & req) != req) 751 continue; 752 753 mi->groups[i].supported = 754 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1]; 755 756 if (mi->groups[i].supported) 757 n_supported++; 758 } 759 760 if (!n_supported) 761 goto use_legacy; 762 763 return; 764 765 use_legacy: 766 msp->is_ht = false; 767 memset(&msp->legacy, 0, sizeof(msp->legacy)); 768 msp->legacy.r = msp->ratelist; 769 msp->legacy.sample_table = msp->sample_table; 770 return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy); 771 } 772 773 static void 774 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband, 775 struct ieee80211_sta *sta, void *priv_sta) 776 { 777 struct minstrel_priv *mp = priv; 778 779 minstrel_ht_update_caps(priv, sband, sta, priv_sta, mp->hw->conf.channel_type); 780 } 781 782 static void 783 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband, 784 struct ieee80211_sta *sta, void *priv_sta, 785 u32 changed, enum nl80211_channel_type oper_chan_type) 786 { 787 minstrel_ht_update_caps(priv, sband, sta, priv_sta, oper_chan_type); 788 } 789 790 static void * 791 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp) 792 { 793 struct ieee80211_supported_band *sband; 794 struct minstrel_ht_sta_priv *msp; 795 struct minstrel_priv *mp = priv; 796 struct ieee80211_hw *hw = mp->hw; 797 int max_rates = 0; 798 int i; 799 800 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 801 sband = hw->wiphy->bands[i]; 802 if (sband && sband->n_bitrates > max_rates) 803 max_rates = sband->n_bitrates; 804 } 805 806 msp = kzalloc(sizeof(struct minstrel_ht_sta), gfp); 807 if (!msp) 808 return NULL; 809 810 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp); 811 if (!msp->ratelist) 812 goto error; 813 814 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp); 815 if (!msp->sample_table) 816 goto error1; 817 818 return msp; 819 820 error1: 821 kfree(msp->ratelist); 822 error: 823 kfree(msp); 824 return NULL; 825 } 826 827 static void 828 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta) 829 { 830 struct minstrel_ht_sta_priv *msp = priv_sta; 831 832 kfree(msp->sample_table); 833 kfree(msp->ratelist); 834 kfree(msp); 835 } 836 837 static void * 838 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) 839 { 840 return mac80211_minstrel.alloc(hw, debugfsdir); 841 } 842 843 static void 844 minstrel_ht_free(void *priv) 845 { 846 mac80211_minstrel.free(priv); 847 } 848 849 static struct rate_control_ops mac80211_minstrel_ht = { 850 .name = "minstrel_ht", 851 .tx_status = minstrel_ht_tx_status, 852 .get_rate = minstrel_ht_get_rate, 853 .rate_init = minstrel_ht_rate_init, 854 .rate_update = minstrel_ht_rate_update, 855 .alloc_sta = minstrel_ht_alloc_sta, 856 .free_sta = minstrel_ht_free_sta, 857 .alloc = minstrel_ht_alloc, 858 .free = minstrel_ht_free, 859 #ifdef CONFIG_MAC80211_DEBUGFS 860 .add_sta_debugfs = minstrel_ht_add_sta_debugfs, 861 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs, 862 #endif 863 }; 864 865 866 static void 867 init_sample_table(void) 868 { 869 int col, i, new_idx; 870 u8 rnd[MCS_GROUP_RATES]; 871 872 memset(sample_table, 0xff, sizeof(sample_table)); 873 for (col = 0; col < SAMPLE_COLUMNS; col++) { 874 for (i = 0; i < MCS_GROUP_RATES; i++) { 875 get_random_bytes(rnd, sizeof(rnd)); 876 new_idx = (i + rnd[i]) % MCS_GROUP_RATES; 877 878 while (sample_table[col][new_idx] != 0xff) 879 new_idx = (new_idx + 1) % MCS_GROUP_RATES; 880 881 sample_table[col][new_idx] = i; 882 } 883 } 884 } 885 886 int __init 887 rc80211_minstrel_ht_init(void) 888 { 889 init_sample_table(); 890 return ieee80211_rate_control_register(&mac80211_minstrel_ht); 891 } 892 893 void 894 rc80211_minstrel_ht_exit(void) 895 { 896 ieee80211_rate_control_unregister(&mac80211_minstrel_ht); 897 } 898