1 /* 2 * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 #include <linux/netdevice.h> 9 #include <linux/types.h> 10 #include <linux/skbuff.h> 11 #include <linux/debugfs.h> 12 #include <linux/random.h> 13 #include <linux/ieee80211.h> 14 #include <net/mac80211.h> 15 #include "rate.h" 16 #include "rc80211_minstrel.h" 17 #include "rc80211_minstrel_ht.h" 18 19 #define AVG_PKT_SIZE 1200 20 21 /* Number of bits for an average sized packet */ 22 #define MCS_NBITS (AVG_PKT_SIZE << 3) 23 24 /* Number of symbols for a packet with (bps) bits per symbol */ 25 #define MCS_NSYMS(bps) ((MCS_NBITS + (bps) - 1) / (bps)) 26 27 /* Transmission time (nanoseconds) for a packet containing (syms) symbols */ 28 #define MCS_SYMBOL_TIME(sgi, syms) \ 29 (sgi ? \ 30 ((syms) * 18000 + 4000) / 5 : /* syms * 3.6 us */ \ 31 ((syms) * 1000) << 2 /* syms * 4 us */ \ 32 ) 33 34 /* Transmit duration for the raw data part of an average sized packet */ 35 #define MCS_DURATION(streams, sgi, bps) MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps))) 36 37 /* 38 * Define group sort order: HT40 -> SGI -> #streams 39 */ 40 #define GROUP_IDX(_streams, _sgi, _ht40) \ 41 MINSTREL_MAX_STREAMS * 2 * _ht40 + \ 42 MINSTREL_MAX_STREAMS * _sgi + \ 43 _streams - 1 44 45 /* MCS rate information for an MCS group */ 46 #define MCS_GROUP(_streams, _sgi, _ht40) \ 47 [GROUP_IDX(_streams, _sgi, _ht40)] = { \ 48 .streams = _streams, \ 49 .flags = \ 50 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \ 51 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \ 52 .duration = { \ 53 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \ 54 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \ 55 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \ 56 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \ 57 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \ 58 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \ 59 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \ 60 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \ 61 } \ 62 } 63 64 #define CCK_DURATION(_bitrate, _short, _len) \ 65 (1000 * (10 /* SIFS */ + \ 66 (_short ? 72 + 24 : 144 + 48 ) + \ 67 (8 * (_len + 4) * 10) / (_bitrate))) 68 69 #define CCK_ACK_DURATION(_bitrate, _short) \ 70 (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) + \ 71 CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE)) 72 73 #define CCK_DURATION_LIST(_short) \ 74 CCK_ACK_DURATION(10, _short), \ 75 CCK_ACK_DURATION(20, _short), \ 76 CCK_ACK_DURATION(55, _short), \ 77 CCK_ACK_DURATION(110, _short) 78 79 #define CCK_GROUP \ 80 [MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS] = { \ 81 .streams = 0, \ 82 .duration = { \ 83 CCK_DURATION_LIST(false), \ 84 CCK_DURATION_LIST(true) \ 85 } \ 86 } 87 88 /* 89 * To enable sufficiently targeted rate sampling, MCS rates are divided into 90 * groups, based on the number of streams and flags (HT40, SGI) that they 91 * use. 92 * 93 * Sortorder has to be fixed for GROUP_IDX macro to be applicable: 94 * HT40 -> SGI -> #streams 95 */ 96 const struct mcs_group minstrel_mcs_groups[] = { 97 MCS_GROUP(1, 0, 0), 98 MCS_GROUP(2, 0, 0), 99 #if MINSTREL_MAX_STREAMS >= 3 100 MCS_GROUP(3, 0, 0), 101 #endif 102 103 MCS_GROUP(1, 1, 0), 104 MCS_GROUP(2, 1, 0), 105 #if MINSTREL_MAX_STREAMS >= 3 106 MCS_GROUP(3, 1, 0), 107 #endif 108 109 MCS_GROUP(1, 0, 1), 110 MCS_GROUP(2, 0, 1), 111 #if MINSTREL_MAX_STREAMS >= 3 112 MCS_GROUP(3, 0, 1), 113 #endif 114 115 MCS_GROUP(1, 1, 1), 116 MCS_GROUP(2, 1, 1), 117 #if MINSTREL_MAX_STREAMS >= 3 118 MCS_GROUP(3, 1, 1), 119 #endif 120 121 /* must be last */ 122 CCK_GROUP 123 }; 124 125 #define MINSTREL_CCK_GROUP (ARRAY_SIZE(minstrel_mcs_groups) - 1) 126 127 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES]; 128 129 static void 130 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi); 131 132 /* 133 * Look up an MCS group index based on mac80211 rate information 134 */ 135 static int 136 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate) 137 { 138 return GROUP_IDX((rate->idx / MCS_GROUP_RATES) + 1, 139 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI), 140 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH)); 141 } 142 143 static struct minstrel_rate_stats * 144 minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 145 struct ieee80211_tx_rate *rate) 146 { 147 int group, idx; 148 149 if (rate->flags & IEEE80211_TX_RC_MCS) { 150 group = minstrel_ht_get_group_idx(rate); 151 idx = rate->idx % MCS_GROUP_RATES; 152 } else { 153 group = MINSTREL_CCK_GROUP; 154 155 for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++) 156 if (rate->idx == mp->cck_rates[idx]) 157 break; 158 159 /* short preamble */ 160 if (!(mi->groups[group].supported & BIT(idx))) 161 idx += 4; 162 } 163 return &mi->groups[group].rates[idx]; 164 } 165 166 static inline struct minstrel_rate_stats * 167 minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index) 168 { 169 return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES]; 170 } 171 172 173 /* 174 * Recalculate success probabilities and counters for a rate using EWMA 175 */ 176 static void 177 minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr) 178 { 179 if (unlikely(mr->attempts > 0)) { 180 mr->sample_skipped = 0; 181 mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts); 182 if (!mr->att_hist) 183 mr->probability = mr->cur_prob; 184 else 185 mr->probability = minstrel_ewma(mr->probability, 186 mr->cur_prob, EWMA_LEVEL); 187 mr->att_hist += mr->attempts; 188 mr->succ_hist += mr->success; 189 } else { 190 mr->sample_skipped++; 191 } 192 mr->last_success = mr->success; 193 mr->last_attempts = mr->attempts; 194 mr->success = 0; 195 mr->attempts = 0; 196 } 197 198 /* 199 * Calculate throughput based on the average A-MPDU length, taking into account 200 * the expected number of retransmissions and their expected length 201 */ 202 static void 203 minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate) 204 { 205 struct minstrel_rate_stats *mr; 206 unsigned int nsecs = 0; 207 unsigned int tp; 208 unsigned int prob; 209 210 mr = &mi->groups[group].rates[rate]; 211 prob = mr->probability; 212 213 if (prob < MINSTREL_FRAC(1, 10)) { 214 mr->cur_tp = 0; 215 return; 216 } 217 218 /* 219 * For the throughput calculation, limit the probability value to 90% to 220 * account for collision related packet error rate fluctuation 221 */ 222 if (prob > MINSTREL_FRAC(9, 10)) 223 prob = MINSTREL_FRAC(9, 10); 224 225 if (group != MINSTREL_CCK_GROUP) 226 nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len); 227 228 nsecs += minstrel_mcs_groups[group].duration[rate]; 229 tp = 1000000 * ((mr->probability * 1000) / nsecs); 230 231 mr->cur_tp = MINSTREL_TRUNC(tp); 232 } 233 234 /* 235 * Update rate statistics and select new primary rates 236 * 237 * Rules for rate selection: 238 * - max_prob_rate must use only one stream, as a tradeoff between delivery 239 * probability and throughput during strong fluctuations 240 * - as long as the max prob rate has a probability of more than 3/4, pick 241 * higher throughput rates, even if the probablity is a bit lower 242 */ 243 static void 244 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 245 { 246 struct minstrel_mcs_group_data *mg; 247 struct minstrel_rate_stats *mr; 248 int cur_prob, cur_prob_tp, cur_tp, cur_tp2; 249 int group, i, index; 250 bool mi_rates_valid = false; 251 252 if (mi->ampdu_packets > 0) { 253 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len, 254 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL); 255 mi->ampdu_len = 0; 256 mi->ampdu_packets = 0; 257 } 258 259 mi->sample_slow = 0; 260 mi->sample_count = 0; 261 262 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { 263 bool mg_rates_valid = false; 264 265 cur_prob = 0; 266 cur_prob_tp = 0; 267 cur_tp = 0; 268 cur_tp2 = 0; 269 270 mg = &mi->groups[group]; 271 if (!mg->supported) 272 continue; 273 274 mi->sample_count++; 275 276 for (i = 0; i < MCS_GROUP_RATES; i++) { 277 if (!(mg->supported & BIT(i))) 278 continue; 279 280 /* initialize rates selections starting indexes */ 281 if (!mg_rates_valid) { 282 mg->max_tp_rate = mg->max_tp_rate2 = 283 mg->max_prob_rate = i; 284 if (!mi_rates_valid) { 285 mi->max_tp_rate = mi->max_tp_rate2 = 286 mi->max_prob_rate = i; 287 mi_rates_valid = true; 288 } 289 mg_rates_valid = true; 290 } 291 292 mr = &mg->rates[i]; 293 mr->retry_updated = false; 294 index = MCS_GROUP_RATES * group + i; 295 minstrel_calc_rate_ewma(mr); 296 minstrel_ht_calc_tp(mi, group, i); 297 298 if (!mr->cur_tp) 299 continue; 300 301 if ((mr->cur_tp > cur_prob_tp && mr->probability > 302 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) { 303 mg->max_prob_rate = index; 304 cur_prob = mr->probability; 305 cur_prob_tp = mr->cur_tp; 306 } 307 308 if (mr->cur_tp > cur_tp) { 309 swap(index, mg->max_tp_rate); 310 cur_tp = mr->cur_tp; 311 mr = minstrel_get_ratestats(mi, index); 312 } 313 314 if (index >= mg->max_tp_rate) 315 continue; 316 317 if (mr->cur_tp > cur_tp2) { 318 mg->max_tp_rate2 = index; 319 cur_tp2 = mr->cur_tp; 320 } 321 } 322 } 323 324 /* try to sample all available rates during each interval */ 325 mi->sample_count *= 8; 326 327 cur_prob = 0; 328 cur_prob_tp = 0; 329 cur_tp = 0; 330 cur_tp2 = 0; 331 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { 332 mg = &mi->groups[group]; 333 if (!mg->supported) 334 continue; 335 336 mr = minstrel_get_ratestats(mi, mg->max_tp_rate); 337 if (cur_tp < mr->cur_tp) { 338 mi->max_tp_rate2 = mi->max_tp_rate; 339 cur_tp2 = cur_tp; 340 mi->max_tp_rate = mg->max_tp_rate; 341 cur_tp = mr->cur_tp; 342 mi->max_prob_streams = minstrel_mcs_groups[group].streams - 1; 343 } 344 345 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2); 346 if (cur_tp2 < mr->cur_tp) { 347 mi->max_tp_rate2 = mg->max_tp_rate2; 348 cur_tp2 = mr->cur_tp; 349 } 350 } 351 352 if (mi->max_prob_streams < 1) 353 mi->max_prob_streams = 1; 354 355 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { 356 mg = &mi->groups[group]; 357 if (!mg->supported) 358 continue; 359 mr = minstrel_get_ratestats(mi, mg->max_prob_rate); 360 if (cur_prob_tp < mr->cur_tp && 361 minstrel_mcs_groups[group].streams <= mi->max_prob_streams) { 362 mi->max_prob_rate = mg->max_prob_rate; 363 cur_prob = mr->cur_prob; 364 cur_prob_tp = mr->cur_tp; 365 } 366 } 367 368 369 mi->stats_update = jiffies; 370 } 371 372 static bool 373 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate) 374 { 375 if (rate->idx < 0) 376 return false; 377 378 if (!rate->count) 379 return false; 380 381 if (rate->flags & IEEE80211_TX_RC_MCS) 382 return true; 383 384 return rate->idx == mp->cck_rates[0] || 385 rate->idx == mp->cck_rates[1] || 386 rate->idx == mp->cck_rates[2] || 387 rate->idx == mp->cck_rates[3]; 388 } 389 390 static void 391 minstrel_next_sample_idx(struct minstrel_ht_sta *mi) 392 { 393 struct minstrel_mcs_group_data *mg; 394 395 for (;;) { 396 mi->sample_group++; 397 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups); 398 mg = &mi->groups[mi->sample_group]; 399 400 if (!mg->supported) 401 continue; 402 403 if (++mg->index >= MCS_GROUP_RATES) { 404 mg->index = 0; 405 if (++mg->column >= ARRAY_SIZE(sample_table)) 406 mg->column = 0; 407 } 408 break; 409 } 410 } 411 412 static void 413 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx, 414 bool primary) 415 { 416 int group, orig_group; 417 418 orig_group = group = *idx / MCS_GROUP_RATES; 419 while (group > 0) { 420 group--; 421 422 if (!mi->groups[group].supported) 423 continue; 424 425 if (minstrel_mcs_groups[group].streams > 426 minstrel_mcs_groups[orig_group].streams) 427 continue; 428 429 if (primary) 430 *idx = mi->groups[group].max_tp_rate; 431 else 432 *idx = mi->groups[group].max_tp_rate2; 433 break; 434 } 435 } 436 437 static void 438 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb) 439 { 440 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 441 struct sta_info *sta = container_of(pubsta, struct sta_info, sta); 442 u16 tid; 443 444 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control))) 445 return; 446 447 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE))) 448 return; 449 450 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; 451 if (likely(sta->ampdu_mlme.tid_tx[tid])) 452 return; 453 454 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO) 455 return; 456 457 ieee80211_start_tx_ba_session(pubsta, tid, 5000); 458 } 459 460 static void 461 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, 462 struct ieee80211_sta *sta, void *priv_sta, 463 struct sk_buff *skb) 464 { 465 struct minstrel_ht_sta_priv *msp = priv_sta; 466 struct minstrel_ht_sta *mi = &msp->ht; 467 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 468 struct ieee80211_tx_rate *ar = info->status.rates; 469 struct minstrel_rate_stats *rate, *rate2; 470 struct minstrel_priv *mp = priv; 471 bool last, update = false; 472 int i; 473 474 if (!msp->is_ht) 475 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb); 476 477 /* This packet was aggregated but doesn't carry status info */ 478 if ((info->flags & IEEE80211_TX_CTL_AMPDU) && 479 !(info->flags & IEEE80211_TX_STAT_AMPDU)) 480 return; 481 482 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) { 483 info->status.ampdu_ack_len = 484 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0); 485 info->status.ampdu_len = 1; 486 } 487 488 mi->ampdu_packets++; 489 mi->ampdu_len += info->status.ampdu_len; 490 491 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) { 492 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len); 493 mi->sample_tries = 1; 494 mi->sample_count--; 495 } 496 497 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) 498 mi->sample_packets += info->status.ampdu_len; 499 500 last = !minstrel_ht_txstat_valid(mp, &ar[0]); 501 for (i = 0; !last; i++) { 502 last = (i == IEEE80211_TX_MAX_RATES - 1) || 503 !minstrel_ht_txstat_valid(mp, &ar[i + 1]); 504 505 rate = minstrel_ht_get_stats(mp, mi, &ar[i]); 506 507 if (last) 508 rate->success += info->status.ampdu_ack_len; 509 510 rate->attempts += ar[i].count * info->status.ampdu_len; 511 } 512 513 /* 514 * check for sudden death of spatial multiplexing, 515 * downgrade to a lower number of streams if necessary. 516 */ 517 rate = minstrel_get_ratestats(mi, mi->max_tp_rate); 518 if (rate->attempts > 30 && 519 MINSTREL_FRAC(rate->success, rate->attempts) < 520 MINSTREL_FRAC(20, 100)) { 521 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true); 522 update = true; 523 } 524 525 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2); 526 if (rate2->attempts > 30 && 527 MINSTREL_FRAC(rate2->success, rate2->attempts) < 528 MINSTREL_FRAC(20, 100)) { 529 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false); 530 update = true; 531 } 532 533 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) { 534 update = true; 535 minstrel_ht_update_stats(mp, mi); 536 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) && 537 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) 538 minstrel_aggr_check(sta, skb); 539 } 540 541 if (update) 542 minstrel_ht_update_rates(mp, mi); 543 } 544 545 static void 546 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 547 int index) 548 { 549 struct minstrel_rate_stats *mr; 550 const struct mcs_group *group; 551 unsigned int tx_time, tx_time_rtscts, tx_time_data; 552 unsigned int cw = mp->cw_min; 553 unsigned int ctime = 0; 554 unsigned int t_slot = 9; /* FIXME */ 555 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len); 556 unsigned int overhead = 0, overhead_rtscts = 0; 557 558 mr = minstrel_get_ratestats(mi, index); 559 if (mr->probability < MINSTREL_FRAC(1, 10)) { 560 mr->retry_count = 1; 561 mr->retry_count_rtscts = 1; 562 return; 563 } 564 565 mr->retry_count = 2; 566 mr->retry_count_rtscts = 2; 567 mr->retry_updated = true; 568 569 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 570 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000; 571 572 /* Contention time for first 2 tries */ 573 ctime = (t_slot * cw) >> 1; 574 cw = min((cw << 1) | 1, mp->cw_max); 575 ctime += (t_slot * cw) >> 1; 576 cw = min((cw << 1) | 1, mp->cw_max); 577 578 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) { 579 overhead = mi->overhead; 580 overhead_rtscts = mi->overhead_rtscts; 581 } 582 583 /* Total TX time for data and Contention after first 2 tries */ 584 tx_time = ctime + 2 * (overhead + tx_time_data); 585 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data); 586 587 /* See how many more tries we can fit inside segment size */ 588 do { 589 /* Contention time for this try */ 590 ctime = (t_slot * cw) >> 1; 591 cw = min((cw << 1) | 1, mp->cw_max); 592 593 /* Total TX time after this try */ 594 tx_time += ctime + overhead + tx_time_data; 595 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data; 596 597 if (tx_time_rtscts < mp->segment_size) 598 mr->retry_count_rtscts++; 599 } while ((tx_time < mp->segment_size) && 600 (++mr->retry_count < mp->max_retry)); 601 } 602 603 604 static void 605 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 606 struct ieee80211_sta_rates *ratetbl, int offset, int index) 607 { 608 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 609 struct minstrel_rate_stats *mr; 610 u8 idx; 611 u16 flags; 612 613 mr = minstrel_get_ratestats(mi, index); 614 if (!mr->retry_updated) 615 minstrel_calc_retransmit(mp, mi, index); 616 617 if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) { 618 ratetbl->rate[offset].count = 2; 619 ratetbl->rate[offset].count_rts = 2; 620 ratetbl->rate[offset].count_cts = 2; 621 } else { 622 ratetbl->rate[offset].count = mr->retry_count; 623 ratetbl->rate[offset].count_cts = mr->retry_count; 624 ratetbl->rate[offset].count_rts = mr->retry_count_rtscts; 625 } 626 627 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) { 628 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)]; 629 flags = 0; 630 } else { 631 idx = index % MCS_GROUP_RATES + 632 (group->streams - 1) * MCS_GROUP_RATES; 633 flags = IEEE80211_TX_RC_MCS | group->flags; 634 } 635 636 if (offset > 0) { 637 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts; 638 flags |= IEEE80211_TX_RC_USE_RTS_CTS; 639 } 640 641 ratetbl->rate[offset].idx = idx; 642 ratetbl->rate[offset].flags = flags; 643 } 644 645 static void 646 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 647 { 648 struct ieee80211_sta_rates *rates; 649 int i = 0; 650 651 rates = kzalloc(sizeof(*rates), GFP_ATOMIC); 652 if (!rates) 653 return; 654 655 /* Start with max_tp_rate */ 656 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate); 657 658 if (mp->hw->max_rates >= 3) { 659 /* At least 3 tx rates supported, use max_tp_rate2 next */ 660 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate2); 661 } 662 663 if (mp->hw->max_rates >= 2) { 664 /* 665 * At least 2 tx rates supported, use max_prob_rate next */ 666 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate); 667 } 668 669 rates->rate[i].idx = -1; 670 rate_control_set_rates(mp->hw, mi->sta, rates); 671 } 672 673 static inline int 674 minstrel_get_duration(int index) 675 { 676 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 677 return group->duration[index % MCS_GROUP_RATES]; 678 } 679 680 static int 681 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 682 { 683 struct minstrel_rate_stats *mr; 684 struct minstrel_mcs_group_data *mg; 685 unsigned int sample_dur, sample_group; 686 int sample_idx = 0; 687 688 if (mi->sample_wait > 0) { 689 mi->sample_wait--; 690 return -1; 691 } 692 693 if (!mi->sample_tries) 694 return -1; 695 696 mg = &mi->groups[mi->sample_group]; 697 sample_idx = sample_table[mg->column][mg->index]; 698 mr = &mg->rates[sample_idx]; 699 sample_group = mi->sample_group; 700 sample_idx += sample_group * MCS_GROUP_RATES; 701 minstrel_next_sample_idx(mi); 702 703 /* 704 * Sampling might add some overhead (RTS, no aggregation) 705 * to the frame. Hence, don't use sampling for the currently 706 * used rates. 707 */ 708 if (sample_idx == mi->max_tp_rate || 709 sample_idx == mi->max_tp_rate2 || 710 sample_idx == mi->max_prob_rate) 711 return -1; 712 713 /* 714 * Do not sample if the probability is already higher than 95% 715 * to avoid wasting airtime. 716 */ 717 if (mr->probability > MINSTREL_FRAC(95, 100)) 718 return -1; 719 720 /* 721 * Make sure that lower rates get sampled only occasionally, 722 * if the link is working perfectly. 723 */ 724 sample_dur = minstrel_get_duration(sample_idx); 725 if (sample_dur >= minstrel_get_duration(mi->max_tp_rate2) && 726 (mi->max_prob_streams < 727 minstrel_mcs_groups[sample_group].streams || 728 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) { 729 if (mr->sample_skipped < 20) 730 return -1; 731 732 if (mi->sample_slow++ > 2) 733 return -1; 734 } 735 mi->sample_tries--; 736 737 return sample_idx; 738 } 739 740 static void 741 minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp, 742 struct minstrel_ht_sta *mi, bool val) 743 { 744 u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported; 745 746 if (!supported || !mi->cck_supported_short) 747 return; 748 749 if (supported & (mi->cck_supported_short << (val * 4))) 750 return; 751 752 supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4); 753 mi->groups[MINSTREL_CCK_GROUP].supported = supported; 754 } 755 756 static void 757 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, 758 struct ieee80211_tx_rate_control *txrc) 759 { 760 const struct mcs_group *sample_group; 761 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); 762 struct ieee80211_tx_rate *rate = &info->status.rates[0]; 763 struct minstrel_ht_sta_priv *msp = priv_sta; 764 struct minstrel_ht_sta *mi = &msp->ht; 765 struct minstrel_priv *mp = priv; 766 int sample_idx; 767 768 if (rate_control_send_low(sta, priv_sta, txrc)) 769 return; 770 771 if (!msp->is_ht) 772 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc); 773 774 info->flags |= mi->tx_flags; 775 minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble); 776 777 /* Don't use EAPOL frames for sampling on non-mrr hw */ 778 if (mp->hw->max_rates == 1 && 779 (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO)) 780 sample_idx = -1; 781 else 782 sample_idx = minstrel_get_sample_rate(mp, mi); 783 784 #ifdef CONFIG_MAC80211_DEBUGFS 785 /* use fixed index if set */ 786 if (mp->fixed_rate_idx != -1) { 787 mi->max_tp_rate = mp->fixed_rate_idx; 788 mi->max_tp_rate2 = mp->fixed_rate_idx; 789 mi->max_prob_rate = mp->fixed_rate_idx; 790 sample_idx = -1; 791 } 792 #endif 793 794 mi->total_packets++; 795 796 /* wraparound */ 797 if (mi->total_packets == ~0) { 798 mi->total_packets = 0; 799 mi->sample_packets = 0; 800 } 801 802 if (sample_idx < 0) 803 return; 804 805 sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES]; 806 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; 807 rate->count = 1; 808 809 if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) { 810 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates); 811 rate->idx = mp->cck_rates[idx]; 812 rate->flags = 0; 813 return; 814 } 815 816 rate->idx = sample_idx % MCS_GROUP_RATES + 817 (sample_group->streams - 1) * MCS_GROUP_RATES; 818 rate->flags = IEEE80211_TX_RC_MCS | sample_group->flags; 819 } 820 821 static void 822 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 823 struct ieee80211_supported_band *sband, 824 struct ieee80211_sta *sta) 825 { 826 int i; 827 828 if (sband->band != IEEE80211_BAND_2GHZ) 829 return; 830 831 if (!(mp->hw->flags & IEEE80211_HW_SUPPORTS_HT_CCK_RATES)) 832 return; 833 834 mi->cck_supported = 0; 835 mi->cck_supported_short = 0; 836 for (i = 0; i < 4; i++) { 837 if (!rate_supported(sta, sband->band, mp->cck_rates[i])) 838 continue; 839 840 mi->cck_supported |= BIT(i); 841 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE) 842 mi->cck_supported_short |= BIT(i); 843 } 844 845 mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported; 846 } 847 848 static void 849 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, 850 struct cfg80211_chan_def *chandef, 851 struct ieee80211_sta *sta, void *priv_sta) 852 { 853 struct minstrel_priv *mp = priv; 854 struct minstrel_ht_sta_priv *msp = priv_sta; 855 struct minstrel_ht_sta *mi = &msp->ht; 856 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs; 857 u16 sta_cap = sta->ht_cap.cap; 858 int n_supported = 0; 859 int ack_dur; 860 int stbc; 861 int i; 862 863 /* fall back to the old minstrel for legacy stations */ 864 if (!sta->ht_cap.ht_supported) 865 goto use_legacy; 866 867 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != 868 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1); 869 870 msp->is_ht = true; 871 memset(mi, 0, sizeof(*mi)); 872 873 mi->sta = sta; 874 mi->stats_update = jiffies; 875 876 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0); 877 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0); 878 mi->overhead += ack_dur; 879 mi->overhead_rtscts = mi->overhead + 2 * ack_dur; 880 881 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1); 882 883 /* When using MRR, sample more on the first attempt, without delay */ 884 if (mp->has_mrr) { 885 mi->sample_count = 16; 886 mi->sample_wait = 0; 887 } else { 888 mi->sample_count = 8; 889 mi->sample_wait = 8; 890 } 891 mi->sample_tries = 4; 892 893 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >> 894 IEEE80211_HT_CAP_RX_STBC_SHIFT; 895 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT; 896 897 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING) 898 mi->tx_flags |= IEEE80211_TX_CTL_LDPC; 899 900 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) { 901 mi->groups[i].supported = 0; 902 if (i == MINSTREL_CCK_GROUP) { 903 minstrel_ht_update_cck(mp, mi, sband, sta); 904 continue; 905 } 906 907 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) { 908 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) { 909 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40)) 910 continue; 911 } else { 912 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20)) 913 continue; 914 } 915 } 916 917 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH && 918 sta->bandwidth < IEEE80211_STA_RX_BW_40) 919 continue; 920 921 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */ 922 if (sta->smps_mode == IEEE80211_SMPS_STATIC && 923 minstrel_mcs_groups[i].streams > 1) 924 continue; 925 926 mi->groups[i].supported = 927 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1]; 928 929 if (mi->groups[i].supported) 930 n_supported++; 931 } 932 933 if (!n_supported) 934 goto use_legacy; 935 936 /* create an initial rate table with the lowest supported rates */ 937 minstrel_ht_update_stats(mp, mi); 938 minstrel_ht_update_rates(mp, mi); 939 940 return; 941 942 use_legacy: 943 msp->is_ht = false; 944 memset(&msp->legacy, 0, sizeof(msp->legacy)); 945 msp->legacy.r = msp->ratelist; 946 msp->legacy.sample_table = msp->sample_table; 947 return mac80211_minstrel.rate_init(priv, sband, chandef, sta, 948 &msp->legacy); 949 } 950 951 static void 952 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband, 953 struct cfg80211_chan_def *chandef, 954 struct ieee80211_sta *sta, void *priv_sta) 955 { 956 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta); 957 } 958 959 static void 960 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband, 961 struct cfg80211_chan_def *chandef, 962 struct ieee80211_sta *sta, void *priv_sta, 963 u32 changed) 964 { 965 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta); 966 } 967 968 static void * 969 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp) 970 { 971 struct ieee80211_supported_band *sband; 972 struct minstrel_ht_sta_priv *msp; 973 struct minstrel_priv *mp = priv; 974 struct ieee80211_hw *hw = mp->hw; 975 int max_rates = 0; 976 int i; 977 978 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 979 sband = hw->wiphy->bands[i]; 980 if (sband && sband->n_bitrates > max_rates) 981 max_rates = sband->n_bitrates; 982 } 983 984 msp = kzalloc(sizeof(*msp), gfp); 985 if (!msp) 986 return NULL; 987 988 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp); 989 if (!msp->ratelist) 990 goto error; 991 992 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp); 993 if (!msp->sample_table) 994 goto error1; 995 996 return msp; 997 998 error1: 999 kfree(msp->ratelist); 1000 error: 1001 kfree(msp); 1002 return NULL; 1003 } 1004 1005 static void 1006 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta) 1007 { 1008 struct minstrel_ht_sta_priv *msp = priv_sta; 1009 1010 kfree(msp->sample_table); 1011 kfree(msp->ratelist); 1012 kfree(msp); 1013 } 1014 1015 static void * 1016 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) 1017 { 1018 return mac80211_minstrel.alloc(hw, debugfsdir); 1019 } 1020 1021 static void 1022 minstrel_ht_free(void *priv) 1023 { 1024 mac80211_minstrel.free(priv); 1025 } 1026 1027 static struct rate_control_ops mac80211_minstrel_ht = { 1028 .name = "minstrel_ht", 1029 .tx_status = minstrel_ht_tx_status, 1030 .get_rate = minstrel_ht_get_rate, 1031 .rate_init = minstrel_ht_rate_init, 1032 .rate_update = minstrel_ht_rate_update, 1033 .alloc_sta = minstrel_ht_alloc_sta, 1034 .free_sta = minstrel_ht_free_sta, 1035 .alloc = minstrel_ht_alloc, 1036 .free = minstrel_ht_free, 1037 #ifdef CONFIG_MAC80211_DEBUGFS 1038 .add_sta_debugfs = minstrel_ht_add_sta_debugfs, 1039 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs, 1040 #endif 1041 }; 1042 1043 1044 static void 1045 init_sample_table(void) 1046 { 1047 int col, i, new_idx; 1048 u8 rnd[MCS_GROUP_RATES]; 1049 1050 memset(sample_table, 0xff, sizeof(sample_table)); 1051 for (col = 0; col < SAMPLE_COLUMNS; col++) { 1052 for (i = 0; i < MCS_GROUP_RATES; i++) { 1053 get_random_bytes(rnd, sizeof(rnd)); 1054 new_idx = (i + rnd[i]) % MCS_GROUP_RATES; 1055 1056 while (sample_table[col][new_idx] != 0xff) 1057 new_idx = (new_idx + 1) % MCS_GROUP_RATES; 1058 1059 sample_table[col][new_idx] = i; 1060 } 1061 } 1062 } 1063 1064 int __init 1065 rc80211_minstrel_ht_init(void) 1066 { 1067 init_sample_table(); 1068 return ieee80211_rate_control_register(&mac80211_minstrel_ht); 1069 } 1070 1071 void 1072 rc80211_minstrel_ht_exit(void) 1073 { 1074 ieee80211_rate_control_unregister(&mac80211_minstrel_ht); 1075 } 1076