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) DIV_ROUND_UP(MCS_NBITS, (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] __read_mostly; 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 / 8) + 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 % 8; 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]; 229 230 /* prob is scaled - see MINSTREL_FRAC above */ 231 tp = 1000000 * ((prob * 1000) / nsecs); 232 mr->cur_tp = MINSTREL_TRUNC(tp); 233 } 234 235 /* 236 * Update rate statistics and select new primary rates 237 * 238 * Rules for rate selection: 239 * - max_prob_rate must use only one stream, as a tradeoff between delivery 240 * probability and throughput during strong fluctuations 241 * - as long as the max prob rate has a probability of more than 3/4, pick 242 * higher throughput rates, even if the probablity is a bit lower 243 */ 244 static void 245 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 246 { 247 struct minstrel_mcs_group_data *mg; 248 struct minstrel_rate_stats *mr; 249 int cur_prob, cur_prob_tp, cur_tp, cur_tp2; 250 int group, i, index; 251 bool mi_rates_valid = false; 252 253 if (mi->ampdu_packets > 0) { 254 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len, 255 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL); 256 mi->ampdu_len = 0; 257 mi->ampdu_packets = 0; 258 } 259 260 mi->sample_slow = 0; 261 mi->sample_count = 0; 262 263 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { 264 bool mg_rates_valid = false; 265 266 cur_prob = 0; 267 cur_prob_tp = 0; 268 cur_tp = 0; 269 cur_tp2 = 0; 270 271 mg = &mi->groups[group]; 272 if (!mg->supported) 273 continue; 274 275 mi->sample_count++; 276 277 for (i = 0; i < MCS_GROUP_RATES; i++) { 278 if (!(mg->supported & BIT(i))) 279 continue; 280 281 index = MCS_GROUP_RATES * group + i; 282 283 /* initialize rates selections starting indexes */ 284 if (!mg_rates_valid) { 285 mg->max_tp_rate = mg->max_tp_rate2 = 286 mg->max_prob_rate = i; 287 if (!mi_rates_valid) { 288 mi->max_tp_rate = mi->max_tp_rate2 = 289 mi->max_prob_rate = index; 290 mi_rates_valid = true; 291 } 292 mg_rates_valid = true; 293 } 294 295 mr = &mg->rates[i]; 296 mr->retry_updated = false; 297 minstrel_calc_rate_ewma(mr); 298 minstrel_ht_calc_tp(mi, group, i); 299 300 if (!mr->cur_tp) 301 continue; 302 303 if ((mr->cur_tp > cur_prob_tp && mr->probability > 304 MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) { 305 mg->max_prob_rate = index; 306 cur_prob = mr->probability; 307 cur_prob_tp = mr->cur_tp; 308 } 309 310 if (mr->cur_tp > cur_tp) { 311 swap(index, mg->max_tp_rate); 312 cur_tp = mr->cur_tp; 313 mr = minstrel_get_ratestats(mi, index); 314 } 315 316 if (index >= mg->max_tp_rate) 317 continue; 318 319 if (mr->cur_tp > cur_tp2) { 320 mg->max_tp_rate2 = index; 321 cur_tp2 = mr->cur_tp; 322 } 323 } 324 } 325 326 /* try to sample all available rates during each interval */ 327 mi->sample_count *= 8; 328 329 cur_prob = 0; 330 cur_prob_tp = 0; 331 cur_tp = 0; 332 cur_tp2 = 0; 333 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { 334 mg = &mi->groups[group]; 335 if (!mg->supported) 336 continue; 337 338 mr = minstrel_get_ratestats(mi, mg->max_tp_rate); 339 if (cur_tp < mr->cur_tp) { 340 mi->max_tp_rate2 = mi->max_tp_rate; 341 cur_tp2 = cur_tp; 342 mi->max_tp_rate = mg->max_tp_rate; 343 cur_tp = mr->cur_tp; 344 mi->max_prob_streams = minstrel_mcs_groups[group].streams - 1; 345 } 346 347 mr = minstrel_get_ratestats(mi, mg->max_tp_rate2); 348 if (cur_tp2 < mr->cur_tp) { 349 mi->max_tp_rate2 = mg->max_tp_rate2; 350 cur_tp2 = mr->cur_tp; 351 } 352 } 353 354 if (mi->max_prob_streams < 1) 355 mi->max_prob_streams = 1; 356 357 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { 358 mg = &mi->groups[group]; 359 if (!mg->supported) 360 continue; 361 mr = minstrel_get_ratestats(mi, mg->max_prob_rate); 362 if (cur_prob_tp < mr->cur_tp && 363 minstrel_mcs_groups[group].streams <= mi->max_prob_streams) { 364 mi->max_prob_rate = mg->max_prob_rate; 365 cur_prob = mr->cur_prob; 366 cur_prob_tp = mr->cur_tp; 367 } 368 } 369 370 #ifdef CONFIG_MAC80211_DEBUGFS 371 /* use fixed index if set */ 372 if (mp->fixed_rate_idx != -1) { 373 mi->max_tp_rate = mp->fixed_rate_idx; 374 mi->max_tp_rate2 = mp->fixed_rate_idx; 375 mi->max_prob_rate = mp->fixed_rate_idx; 376 } 377 #endif 378 379 mi->stats_update = jiffies; 380 } 381 382 static bool 383 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate) 384 { 385 if (rate->idx < 0) 386 return false; 387 388 if (!rate->count) 389 return false; 390 391 if (rate->flags & IEEE80211_TX_RC_MCS) 392 return true; 393 394 return rate->idx == mp->cck_rates[0] || 395 rate->idx == mp->cck_rates[1] || 396 rate->idx == mp->cck_rates[2] || 397 rate->idx == mp->cck_rates[3]; 398 } 399 400 static void 401 minstrel_next_sample_idx(struct minstrel_ht_sta *mi) 402 { 403 struct minstrel_mcs_group_data *mg; 404 405 for (;;) { 406 mi->sample_group++; 407 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups); 408 mg = &mi->groups[mi->sample_group]; 409 410 if (!mg->supported) 411 continue; 412 413 if (++mg->index >= MCS_GROUP_RATES) { 414 mg->index = 0; 415 if (++mg->column >= ARRAY_SIZE(sample_table)) 416 mg->column = 0; 417 } 418 break; 419 } 420 } 421 422 static void 423 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx, 424 bool primary) 425 { 426 int group, orig_group; 427 428 orig_group = group = *idx / MCS_GROUP_RATES; 429 while (group > 0) { 430 group--; 431 432 if (!mi->groups[group].supported) 433 continue; 434 435 if (minstrel_mcs_groups[group].streams > 436 minstrel_mcs_groups[orig_group].streams) 437 continue; 438 439 if (primary) 440 *idx = mi->groups[group].max_tp_rate; 441 else 442 *idx = mi->groups[group].max_tp_rate2; 443 break; 444 } 445 } 446 447 static void 448 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb) 449 { 450 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 451 struct sta_info *sta = container_of(pubsta, struct sta_info, sta); 452 u16 tid; 453 454 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control))) 455 return; 456 457 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE))) 458 return; 459 460 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; 461 if (likely(sta->ampdu_mlme.tid_tx[tid])) 462 return; 463 464 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO) 465 return; 466 467 ieee80211_start_tx_ba_session(pubsta, tid, 5000); 468 } 469 470 static void 471 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, 472 struct ieee80211_sta *sta, void *priv_sta, 473 struct sk_buff *skb) 474 { 475 struct minstrel_ht_sta_priv *msp = priv_sta; 476 struct minstrel_ht_sta *mi = &msp->ht; 477 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 478 struct ieee80211_tx_rate *ar = info->status.rates; 479 struct minstrel_rate_stats *rate, *rate2; 480 struct minstrel_priv *mp = priv; 481 bool last, update = false; 482 int i; 483 484 if (!msp->is_ht) 485 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb); 486 487 /* This packet was aggregated but doesn't carry status info */ 488 if ((info->flags & IEEE80211_TX_CTL_AMPDU) && 489 !(info->flags & IEEE80211_TX_STAT_AMPDU)) 490 return; 491 492 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) { 493 info->status.ampdu_ack_len = 494 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0); 495 info->status.ampdu_len = 1; 496 } 497 498 mi->ampdu_packets++; 499 mi->ampdu_len += info->status.ampdu_len; 500 501 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) { 502 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len); 503 mi->sample_tries = 1; 504 mi->sample_count--; 505 } 506 507 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) 508 mi->sample_packets += info->status.ampdu_len; 509 510 last = !minstrel_ht_txstat_valid(mp, &ar[0]); 511 for (i = 0; !last; i++) { 512 last = (i == IEEE80211_TX_MAX_RATES - 1) || 513 !minstrel_ht_txstat_valid(mp, &ar[i + 1]); 514 515 rate = minstrel_ht_get_stats(mp, mi, &ar[i]); 516 517 if (last) 518 rate->success += info->status.ampdu_ack_len; 519 520 rate->attempts += ar[i].count * info->status.ampdu_len; 521 } 522 523 /* 524 * check for sudden death of spatial multiplexing, 525 * downgrade to a lower number of streams if necessary. 526 */ 527 rate = minstrel_get_ratestats(mi, mi->max_tp_rate); 528 if (rate->attempts > 30 && 529 MINSTREL_FRAC(rate->success, rate->attempts) < 530 MINSTREL_FRAC(20, 100)) { 531 minstrel_downgrade_rate(mi, &mi->max_tp_rate, true); 532 update = true; 533 } 534 535 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2); 536 if (rate2->attempts > 30 && 537 MINSTREL_FRAC(rate2->success, rate2->attempts) < 538 MINSTREL_FRAC(20, 100)) { 539 minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false); 540 update = true; 541 } 542 543 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) { 544 update = true; 545 minstrel_ht_update_stats(mp, mi); 546 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) && 547 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) 548 minstrel_aggr_check(sta, skb); 549 } 550 551 if (update) 552 minstrel_ht_update_rates(mp, mi); 553 } 554 555 static void 556 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 557 int index) 558 { 559 struct minstrel_rate_stats *mr; 560 const struct mcs_group *group; 561 unsigned int tx_time, tx_time_rtscts, tx_time_data; 562 unsigned int cw = mp->cw_min; 563 unsigned int ctime = 0; 564 unsigned int t_slot = 9; /* FIXME */ 565 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len); 566 unsigned int overhead = 0, overhead_rtscts = 0; 567 568 mr = minstrel_get_ratestats(mi, index); 569 if (mr->probability < MINSTREL_FRAC(1, 10)) { 570 mr->retry_count = 1; 571 mr->retry_count_rtscts = 1; 572 return; 573 } 574 575 mr->retry_count = 2; 576 mr->retry_count_rtscts = 2; 577 mr->retry_updated = true; 578 579 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 580 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000; 581 582 /* Contention time for first 2 tries */ 583 ctime = (t_slot * cw) >> 1; 584 cw = min((cw << 1) | 1, mp->cw_max); 585 ctime += (t_slot * cw) >> 1; 586 cw = min((cw << 1) | 1, mp->cw_max); 587 588 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) { 589 overhead = mi->overhead; 590 overhead_rtscts = mi->overhead_rtscts; 591 } 592 593 /* Total TX time for data and Contention after first 2 tries */ 594 tx_time = ctime + 2 * (overhead + tx_time_data); 595 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data); 596 597 /* See how many more tries we can fit inside segment size */ 598 do { 599 /* Contention time for this try */ 600 ctime = (t_slot * cw) >> 1; 601 cw = min((cw << 1) | 1, mp->cw_max); 602 603 /* Total TX time after this try */ 604 tx_time += ctime + overhead + tx_time_data; 605 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data; 606 607 if (tx_time_rtscts < mp->segment_size) 608 mr->retry_count_rtscts++; 609 } while ((tx_time < mp->segment_size) && 610 (++mr->retry_count < mp->max_retry)); 611 } 612 613 614 static void 615 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 616 struct ieee80211_sta_rates *ratetbl, int offset, int index) 617 { 618 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 619 struct minstrel_rate_stats *mr; 620 u8 idx; 621 u16 flags; 622 623 mr = minstrel_get_ratestats(mi, index); 624 if (!mr->retry_updated) 625 minstrel_calc_retransmit(mp, mi, index); 626 627 if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) { 628 ratetbl->rate[offset].count = 2; 629 ratetbl->rate[offset].count_rts = 2; 630 ratetbl->rate[offset].count_cts = 2; 631 } else { 632 ratetbl->rate[offset].count = mr->retry_count; 633 ratetbl->rate[offset].count_cts = mr->retry_count; 634 ratetbl->rate[offset].count_rts = mr->retry_count_rtscts; 635 } 636 637 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) { 638 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)]; 639 flags = 0; 640 } else { 641 idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8; 642 flags = IEEE80211_TX_RC_MCS | group->flags; 643 } 644 645 if (offset > 0) { 646 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts; 647 flags |= IEEE80211_TX_RC_USE_RTS_CTS; 648 } 649 650 ratetbl->rate[offset].idx = idx; 651 ratetbl->rate[offset].flags = flags; 652 } 653 654 static void 655 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 656 { 657 struct ieee80211_sta_rates *rates; 658 int i = 0; 659 660 rates = kzalloc(sizeof(*rates), GFP_ATOMIC); 661 if (!rates) 662 return; 663 664 /* Start with max_tp_rate */ 665 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate); 666 667 if (mp->hw->max_rates >= 3) { 668 /* At least 3 tx rates supported, use max_tp_rate2 next */ 669 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate2); 670 } 671 672 if (mp->hw->max_rates >= 2) { 673 /* 674 * At least 2 tx rates supported, use max_prob_rate next */ 675 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate); 676 } 677 678 rates->rate[i].idx = -1; 679 rate_control_set_rates(mp->hw, mi->sta, rates); 680 } 681 682 static inline int 683 minstrel_get_duration(int index) 684 { 685 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 686 return group->duration[index % MCS_GROUP_RATES]; 687 } 688 689 static int 690 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 691 { 692 struct minstrel_rate_stats *mr; 693 struct minstrel_mcs_group_data *mg; 694 unsigned int sample_dur, sample_group; 695 int sample_idx = 0; 696 697 if (mi->sample_wait > 0) { 698 mi->sample_wait--; 699 return -1; 700 } 701 702 if (!mi->sample_tries) 703 return -1; 704 705 sample_group = mi->sample_group; 706 mg = &mi->groups[sample_group]; 707 sample_idx = sample_table[mg->column][mg->index]; 708 minstrel_next_sample_idx(mi); 709 710 if (!(mg->supported & BIT(sample_idx))) 711 return -1; 712 713 mr = &mg->rates[sample_idx]; 714 sample_idx += sample_group * MCS_GROUP_RATES; 715 716 /* 717 * Sampling might add some overhead (RTS, no aggregation) 718 * to the frame. Hence, don't use sampling for the currently 719 * used rates. 720 */ 721 if (sample_idx == mi->max_tp_rate || 722 sample_idx == mi->max_tp_rate2 || 723 sample_idx == mi->max_prob_rate) 724 return -1; 725 726 /* 727 * Do not sample if the probability is already higher than 95% 728 * to avoid wasting airtime. 729 */ 730 if (mr->probability > MINSTREL_FRAC(95, 100)) 731 return -1; 732 733 /* 734 * Make sure that lower rates get sampled only occasionally, 735 * if the link is working perfectly. 736 */ 737 sample_dur = minstrel_get_duration(sample_idx); 738 if (sample_dur >= minstrel_get_duration(mi->max_tp_rate2) && 739 (mi->max_prob_streams < 740 minstrel_mcs_groups[sample_group].streams || 741 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) { 742 if (mr->sample_skipped < 20) 743 return -1; 744 745 if (mi->sample_slow++ > 2) 746 return -1; 747 } 748 mi->sample_tries--; 749 750 return sample_idx; 751 } 752 753 static void 754 minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp, 755 struct minstrel_ht_sta *mi, bool val) 756 { 757 u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported; 758 759 if (!supported || !mi->cck_supported_short) 760 return; 761 762 if (supported & (mi->cck_supported_short << (val * 4))) 763 return; 764 765 supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4); 766 mi->groups[MINSTREL_CCK_GROUP].supported = supported; 767 } 768 769 static void 770 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, 771 struct ieee80211_tx_rate_control *txrc) 772 { 773 const struct mcs_group *sample_group; 774 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); 775 struct ieee80211_tx_rate *rate = &info->status.rates[0]; 776 struct minstrel_ht_sta_priv *msp = priv_sta; 777 struct minstrel_ht_sta *mi = &msp->ht; 778 struct minstrel_priv *mp = priv; 779 int sample_idx; 780 781 if (rate_control_send_low(sta, priv_sta, txrc)) 782 return; 783 784 if (!msp->is_ht) 785 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc); 786 787 info->flags |= mi->tx_flags; 788 minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble); 789 790 #ifdef CONFIG_MAC80211_DEBUGFS 791 if (mp->fixed_rate_idx != -1) 792 return; 793 #endif 794 795 /* Don't use EAPOL frames for sampling on non-mrr hw */ 796 if (mp->hw->max_rates == 1 && 797 (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO)) 798 sample_idx = -1; 799 else 800 sample_idx = minstrel_get_sample_rate(mp, mi); 801 802 mi->total_packets++; 803 804 /* wraparound */ 805 if (mi->total_packets == ~0) { 806 mi->total_packets = 0; 807 mi->sample_packets = 0; 808 } 809 810 if (sample_idx < 0) 811 return; 812 813 sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES]; 814 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; 815 rate->count = 1; 816 817 if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) { 818 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates); 819 rate->idx = mp->cck_rates[idx]; 820 rate->flags = 0; 821 return; 822 } 823 824 rate->idx = sample_idx % MCS_GROUP_RATES + 825 (sample_group->streams - 1) * 8; 826 rate->flags = IEEE80211_TX_RC_MCS | sample_group->flags; 827 } 828 829 static void 830 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 831 struct ieee80211_supported_band *sband, 832 struct ieee80211_sta *sta) 833 { 834 int i; 835 836 if (sband->band != IEEE80211_BAND_2GHZ) 837 return; 838 839 if (!(mp->hw->flags & IEEE80211_HW_SUPPORTS_HT_CCK_RATES)) 840 return; 841 842 mi->cck_supported = 0; 843 mi->cck_supported_short = 0; 844 for (i = 0; i < 4; i++) { 845 if (!rate_supported(sta, sband->band, mp->cck_rates[i])) 846 continue; 847 848 mi->cck_supported |= BIT(i); 849 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE) 850 mi->cck_supported_short |= BIT(i); 851 } 852 853 mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported; 854 } 855 856 static void 857 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, 858 struct cfg80211_chan_def *chandef, 859 struct ieee80211_sta *sta, void *priv_sta) 860 { 861 struct minstrel_priv *mp = priv; 862 struct minstrel_ht_sta_priv *msp = priv_sta; 863 struct minstrel_ht_sta *mi = &msp->ht; 864 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs; 865 u16 sta_cap = sta->ht_cap.cap; 866 int n_supported = 0; 867 int ack_dur; 868 int stbc; 869 int i; 870 871 /* fall back to the old minstrel for legacy stations */ 872 if (!sta->ht_cap.ht_supported) 873 goto use_legacy; 874 875 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != 876 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1); 877 878 msp->is_ht = true; 879 memset(mi, 0, sizeof(*mi)); 880 881 mi->sta = sta; 882 mi->stats_update = jiffies; 883 884 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0); 885 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0); 886 mi->overhead += ack_dur; 887 mi->overhead_rtscts = mi->overhead + 2 * ack_dur; 888 889 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1); 890 891 /* When using MRR, sample more on the first attempt, without delay */ 892 if (mp->has_mrr) { 893 mi->sample_count = 16; 894 mi->sample_wait = 0; 895 } else { 896 mi->sample_count = 8; 897 mi->sample_wait = 8; 898 } 899 mi->sample_tries = 4; 900 901 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >> 902 IEEE80211_HT_CAP_RX_STBC_SHIFT; 903 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT; 904 905 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING) 906 mi->tx_flags |= IEEE80211_TX_CTL_LDPC; 907 908 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) { 909 mi->groups[i].supported = 0; 910 if (i == MINSTREL_CCK_GROUP) { 911 minstrel_ht_update_cck(mp, mi, sband, sta); 912 continue; 913 } 914 915 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) { 916 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) { 917 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40)) 918 continue; 919 } else { 920 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20)) 921 continue; 922 } 923 } 924 925 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH && 926 sta->bandwidth < IEEE80211_STA_RX_BW_40) 927 continue; 928 929 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */ 930 if (sta->smps_mode == IEEE80211_SMPS_STATIC && 931 minstrel_mcs_groups[i].streams > 1) 932 continue; 933 934 mi->groups[i].supported = 935 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1]; 936 937 if (mi->groups[i].supported) 938 n_supported++; 939 } 940 941 if (!n_supported) 942 goto use_legacy; 943 944 /* create an initial rate table with the lowest supported rates */ 945 minstrel_ht_update_stats(mp, mi); 946 minstrel_ht_update_rates(mp, mi); 947 948 return; 949 950 use_legacy: 951 msp->is_ht = false; 952 memset(&msp->legacy, 0, sizeof(msp->legacy)); 953 msp->legacy.r = msp->ratelist; 954 msp->legacy.sample_table = msp->sample_table; 955 return mac80211_minstrel.rate_init(priv, sband, chandef, sta, 956 &msp->legacy); 957 } 958 959 static void 960 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband, 961 struct cfg80211_chan_def *chandef, 962 struct ieee80211_sta *sta, void *priv_sta) 963 { 964 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta); 965 } 966 967 static void 968 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband, 969 struct cfg80211_chan_def *chandef, 970 struct ieee80211_sta *sta, void *priv_sta, 971 u32 changed) 972 { 973 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta); 974 } 975 976 static void * 977 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp) 978 { 979 struct ieee80211_supported_band *sband; 980 struct minstrel_ht_sta_priv *msp; 981 struct minstrel_priv *mp = priv; 982 struct ieee80211_hw *hw = mp->hw; 983 int max_rates = 0; 984 int i; 985 986 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 987 sband = hw->wiphy->bands[i]; 988 if (sband && sband->n_bitrates > max_rates) 989 max_rates = sband->n_bitrates; 990 } 991 992 msp = kzalloc(sizeof(*msp), gfp); 993 if (!msp) 994 return NULL; 995 996 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp); 997 if (!msp->ratelist) 998 goto error; 999 1000 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp); 1001 if (!msp->sample_table) 1002 goto error1; 1003 1004 return msp; 1005 1006 error1: 1007 kfree(msp->ratelist); 1008 error: 1009 kfree(msp); 1010 return NULL; 1011 } 1012 1013 static void 1014 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta) 1015 { 1016 struct minstrel_ht_sta_priv *msp = priv_sta; 1017 1018 kfree(msp->sample_table); 1019 kfree(msp->ratelist); 1020 kfree(msp); 1021 } 1022 1023 static void * 1024 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) 1025 { 1026 return mac80211_minstrel.alloc(hw, debugfsdir); 1027 } 1028 1029 static void 1030 minstrel_ht_free(void *priv) 1031 { 1032 mac80211_minstrel.free(priv); 1033 } 1034 1035 static u32 minstrel_ht_get_expected_throughput(void *priv_sta) 1036 { 1037 struct minstrel_ht_sta_priv *msp = priv_sta; 1038 struct minstrel_ht_sta *mi = &msp->ht; 1039 int i, j; 1040 1041 if (!msp->is_ht) 1042 return mac80211_minstrel.get_expected_throughput(priv_sta); 1043 1044 i = mi->max_tp_rate / MCS_GROUP_RATES; 1045 j = mi->max_tp_rate % MCS_GROUP_RATES; 1046 1047 /* convert cur_tp from pkt per second in kbps */ 1048 return mi->groups[i].rates[j].cur_tp * AVG_PKT_SIZE * 8 / 1024; 1049 } 1050 1051 static const struct rate_control_ops mac80211_minstrel_ht = { 1052 .name = "minstrel_ht", 1053 .tx_status = minstrel_ht_tx_status, 1054 .get_rate = minstrel_ht_get_rate, 1055 .rate_init = minstrel_ht_rate_init, 1056 .rate_update = minstrel_ht_rate_update, 1057 .alloc_sta = minstrel_ht_alloc_sta, 1058 .free_sta = minstrel_ht_free_sta, 1059 .alloc = minstrel_ht_alloc, 1060 .free = minstrel_ht_free, 1061 #ifdef CONFIG_MAC80211_DEBUGFS 1062 .add_sta_debugfs = minstrel_ht_add_sta_debugfs, 1063 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs, 1064 #endif 1065 .get_expected_throughput = minstrel_ht_get_expected_throughput, 1066 }; 1067 1068 1069 static void __init init_sample_table(void) 1070 { 1071 int col, i, new_idx; 1072 u8 rnd[MCS_GROUP_RATES]; 1073 1074 memset(sample_table, 0xff, sizeof(sample_table)); 1075 for (col = 0; col < SAMPLE_COLUMNS; col++) { 1076 prandom_bytes(rnd, sizeof(rnd)); 1077 for (i = 0; i < MCS_GROUP_RATES; i++) { 1078 new_idx = (i + rnd[i]) % MCS_GROUP_RATES; 1079 while (sample_table[col][new_idx] != 0xff) 1080 new_idx = (new_idx + 1) % MCS_GROUP_RATES; 1081 1082 sample_table[col][new_idx] = i; 1083 } 1084 } 1085 } 1086 1087 int __init 1088 rc80211_minstrel_ht_init(void) 1089 { 1090 init_sample_table(); 1091 return ieee80211_rate_control_register(&mac80211_minstrel_ht); 1092 } 1093 1094 void 1095 rc80211_minstrel_ht_exit(void) 1096 { 1097 ieee80211_rate_control_unregister(&mac80211_minstrel_ht); 1098 } 1099