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 / 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 % 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 * Find & sort topmost throughput rates 237 * 238 * If multiple rates provide equal throughput the sorting is based on their 239 * current success probability. Higher success probability is preferred among 240 * MCS groups, CCK rates do not provide aggregation and are therefore at last. 241 */ 242 static void 243 minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u8 index, 244 u8 *tp_list) 245 { 246 int cur_group, cur_idx, cur_thr, cur_prob; 247 int tmp_group, tmp_idx, tmp_thr, tmp_prob; 248 int j = MAX_THR_RATES; 249 250 cur_group = index / MCS_GROUP_RATES; 251 cur_idx = index % MCS_GROUP_RATES; 252 cur_thr = mi->groups[cur_group].rates[cur_idx].cur_tp; 253 cur_prob = mi->groups[cur_group].rates[cur_idx].probability; 254 255 tmp_group = tp_list[j - 1] / MCS_GROUP_RATES; 256 tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES; 257 tmp_thr = mi->groups[tmp_group].rates[tmp_idx].cur_tp; 258 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability; 259 260 while (j > 0 && (cur_thr > tmp_thr || 261 (cur_thr == tmp_thr && cur_prob > tmp_prob))) { 262 j--; 263 tmp_group = tp_list[j - 1] / MCS_GROUP_RATES; 264 tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES; 265 tmp_thr = mi->groups[tmp_group].rates[tmp_idx].cur_tp; 266 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability; 267 } 268 269 if (j < MAX_THR_RATES - 1) { 270 memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) * 271 (MAX_THR_RATES - (j + 1)))); 272 } 273 if (j < MAX_THR_RATES) 274 tp_list[j] = index; 275 } 276 277 /* 278 * Find and set the topmost probability rate per sta and per group 279 */ 280 static void 281 minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u8 index) 282 { 283 struct minstrel_mcs_group_data *mg; 284 struct minstrel_rate_stats *mr; 285 int tmp_group, tmp_idx, tmp_tp, tmp_prob, max_tp_group; 286 287 mg = &mi->groups[index / MCS_GROUP_RATES]; 288 mr = &mg->rates[index % MCS_GROUP_RATES]; 289 290 tmp_group = mi->max_prob_rate / MCS_GROUP_RATES; 291 tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES; 292 tmp_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp; 293 tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability; 294 295 /* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from 296 * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */ 297 max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES; 298 if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) && 299 (max_tp_group != MINSTREL_CCK_GROUP)) 300 return; 301 302 if (mr->probability > MINSTREL_FRAC(75, 100)) { 303 if (mr->cur_tp > tmp_tp) 304 mi->max_prob_rate = index; 305 if (mr->cur_tp > mg->rates[mg->max_group_prob_rate].cur_tp) 306 mg->max_group_prob_rate = index; 307 } else { 308 if (mr->probability > tmp_prob) 309 mi->max_prob_rate = index; 310 if (mr->probability > mg->rates[mg->max_group_prob_rate].probability) 311 mg->max_group_prob_rate = index; 312 } 313 } 314 315 316 /* 317 * Assign new rate set per sta and use CCK rates only if the fastest 318 * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted 319 * rate sets where MCS and CCK rates are mixed, because CCK rates can 320 * not use aggregation. 321 */ 322 static void 323 minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi, 324 u8 tmp_mcs_tp_rate[MAX_THR_RATES], 325 u8 tmp_cck_tp_rate[MAX_THR_RATES]) 326 { 327 unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp; 328 int i; 329 330 tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES; 331 tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES; 332 tmp_cck_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp; 333 334 tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES; 335 tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES; 336 tmp_mcs_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp; 337 338 if (tmp_cck_tp > tmp_mcs_tp) { 339 for(i = 0; i < MAX_THR_RATES; i++) { 340 minstrel_ht_sort_best_tp_rates(mi, tmp_cck_tp_rate[i], 341 tmp_mcs_tp_rate); 342 } 343 } 344 345 } 346 347 /* 348 * Try to increase robustness of max_prob rate by decrease number of 349 * streams if possible. 350 */ 351 static inline void 352 minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi) 353 { 354 struct minstrel_mcs_group_data *mg; 355 struct minstrel_rate_stats *mr; 356 int tmp_max_streams, group; 357 int tmp_tp = 0; 358 359 tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] / 360 MCS_GROUP_RATES].streams; 361 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { 362 mg = &mi->groups[group]; 363 if (!mg->supported || group == MINSTREL_CCK_GROUP) 364 continue; 365 mr = minstrel_get_ratestats(mi, mg->max_group_prob_rate); 366 if (tmp_tp < mr->cur_tp && 367 (minstrel_mcs_groups[group].streams < tmp_max_streams)) { 368 mi->max_prob_rate = mg->max_group_prob_rate; 369 tmp_tp = mr->cur_tp; 370 } 371 } 372 } 373 374 /* 375 * Update rate statistics and select new primary rates 376 * 377 * Rules for rate selection: 378 * - max_prob_rate must use only one stream, as a tradeoff between delivery 379 * probability and throughput during strong fluctuations 380 * - as long as the max prob rate has a probability of more than 75%, pick 381 * higher throughput rates, even if the probablity is a bit lower 382 */ 383 static void 384 minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 385 { 386 struct minstrel_mcs_group_data *mg; 387 struct minstrel_rate_stats *mr; 388 int group, i, j; 389 u8 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES]; 390 u8 tmp_cck_tp_rate[MAX_THR_RATES], index; 391 392 if (mi->ampdu_packets > 0) { 393 mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len, 394 MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL); 395 mi->ampdu_len = 0; 396 mi->ampdu_packets = 0; 397 } 398 399 mi->sample_slow = 0; 400 mi->sample_count = 0; 401 402 /* Initialize global rate indexes */ 403 for(j = 0; j < MAX_THR_RATES; j++){ 404 tmp_mcs_tp_rate[j] = 0; 405 tmp_cck_tp_rate[j] = 0; 406 } 407 408 /* Find best rate sets within all MCS groups*/ 409 for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { 410 411 mg = &mi->groups[group]; 412 if (!mg->supported) 413 continue; 414 415 mi->sample_count++; 416 417 /* (re)Initialize group rate indexes */ 418 for(j = 0; j < MAX_THR_RATES; j++) 419 tmp_group_tp_rate[j] = group; 420 421 for (i = 0; i < MCS_GROUP_RATES; i++) { 422 if (!(mg->supported & BIT(i))) 423 continue; 424 425 index = MCS_GROUP_RATES * group + i; 426 427 mr = &mg->rates[i]; 428 mr->retry_updated = false; 429 minstrel_calc_rate_ewma(mr); 430 minstrel_ht_calc_tp(mi, group, i); 431 432 if (!mr->cur_tp) 433 continue; 434 435 /* Find max throughput rate set */ 436 if (group != MINSTREL_CCK_GROUP) { 437 minstrel_ht_sort_best_tp_rates(mi, index, 438 tmp_mcs_tp_rate); 439 } else if (group == MINSTREL_CCK_GROUP) { 440 minstrel_ht_sort_best_tp_rates(mi, index, 441 tmp_cck_tp_rate); 442 } 443 444 /* Find max throughput rate set within a group */ 445 minstrel_ht_sort_best_tp_rates(mi, index, 446 tmp_group_tp_rate); 447 448 /* Find max probability rate per group and global */ 449 minstrel_ht_set_best_prob_rate(mi, index); 450 } 451 452 memcpy(mg->max_group_tp_rate, tmp_group_tp_rate, 453 sizeof(mg->max_group_tp_rate)); 454 } 455 456 /* Assign new rate set per sta */ 457 minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate); 458 memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate)); 459 460 /* Try to increase robustness of max_prob_rate*/ 461 minstrel_ht_prob_rate_reduce_streams(mi); 462 463 /* try to sample all available rates during each interval */ 464 mi->sample_count *= 8; 465 466 #ifdef CONFIG_MAC80211_DEBUGFS 467 /* use fixed index if set */ 468 if (mp->fixed_rate_idx != -1) { 469 for (i = 0; i < 4; i++) 470 mi->max_tp_rate[i] = mp->fixed_rate_idx; 471 mi->max_prob_rate = mp->fixed_rate_idx; 472 } 473 #endif 474 475 /* Reset update timer */ 476 mi->stats_update = jiffies; 477 } 478 479 static bool 480 minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate) 481 { 482 if (rate->idx < 0) 483 return false; 484 485 if (!rate->count) 486 return false; 487 488 if (rate->flags & IEEE80211_TX_RC_MCS) 489 return true; 490 491 return rate->idx == mp->cck_rates[0] || 492 rate->idx == mp->cck_rates[1] || 493 rate->idx == mp->cck_rates[2] || 494 rate->idx == mp->cck_rates[3]; 495 } 496 497 static void 498 minstrel_next_sample_idx(struct minstrel_ht_sta *mi) 499 { 500 struct minstrel_mcs_group_data *mg; 501 502 for (;;) { 503 mi->sample_group++; 504 mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups); 505 mg = &mi->groups[mi->sample_group]; 506 507 if (!mg->supported) 508 continue; 509 510 if (++mg->index >= MCS_GROUP_RATES) { 511 mg->index = 0; 512 if (++mg->column >= ARRAY_SIZE(sample_table)) 513 mg->column = 0; 514 } 515 break; 516 } 517 } 518 519 static void 520 minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u8 *idx, bool primary) 521 { 522 int group, orig_group; 523 524 orig_group = group = *idx / MCS_GROUP_RATES; 525 while (group > 0) { 526 group--; 527 528 if (!mi->groups[group].supported) 529 continue; 530 531 if (minstrel_mcs_groups[group].streams > 532 minstrel_mcs_groups[orig_group].streams) 533 continue; 534 535 if (primary) 536 *idx = mi->groups[group].max_group_tp_rate[0]; 537 else 538 *idx = mi->groups[group].max_group_tp_rate[1]; 539 break; 540 } 541 } 542 543 static void 544 minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb) 545 { 546 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 547 struct sta_info *sta = container_of(pubsta, struct sta_info, sta); 548 u16 tid; 549 550 if (unlikely(!ieee80211_is_data_qos(hdr->frame_control))) 551 return; 552 553 if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE))) 554 return; 555 556 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; 557 if (likely(sta->ampdu_mlme.tid_tx[tid])) 558 return; 559 560 if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO) 561 return; 562 563 ieee80211_start_tx_ba_session(pubsta, tid, 5000); 564 } 565 566 static void 567 minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, 568 struct ieee80211_sta *sta, void *priv_sta, 569 struct sk_buff *skb) 570 { 571 struct minstrel_ht_sta_priv *msp = priv_sta; 572 struct minstrel_ht_sta *mi = &msp->ht; 573 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 574 struct ieee80211_tx_rate *ar = info->status.rates; 575 struct minstrel_rate_stats *rate, *rate2; 576 struct minstrel_priv *mp = priv; 577 bool last, update = false; 578 int i; 579 580 if (!msp->is_ht) 581 return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb); 582 583 /* This packet was aggregated but doesn't carry status info */ 584 if ((info->flags & IEEE80211_TX_CTL_AMPDU) && 585 !(info->flags & IEEE80211_TX_STAT_AMPDU)) 586 return; 587 588 if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) { 589 info->status.ampdu_ack_len = 590 (info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0); 591 info->status.ampdu_len = 1; 592 } 593 594 mi->ampdu_packets++; 595 mi->ampdu_len += info->status.ampdu_len; 596 597 if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) { 598 mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len); 599 mi->sample_tries = 1; 600 mi->sample_count--; 601 } 602 603 if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) 604 mi->sample_packets += info->status.ampdu_len; 605 606 last = !minstrel_ht_txstat_valid(mp, &ar[0]); 607 for (i = 0; !last; i++) { 608 last = (i == IEEE80211_TX_MAX_RATES - 1) || 609 !minstrel_ht_txstat_valid(mp, &ar[i + 1]); 610 611 rate = minstrel_ht_get_stats(mp, mi, &ar[i]); 612 613 if (last) 614 rate->success += info->status.ampdu_ack_len; 615 616 rate->attempts += ar[i].count * info->status.ampdu_len; 617 } 618 619 /* 620 * check for sudden death of spatial multiplexing, 621 * downgrade to a lower number of streams if necessary. 622 */ 623 rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]); 624 if (rate->attempts > 30 && 625 MINSTREL_FRAC(rate->success, rate->attempts) < 626 MINSTREL_FRAC(20, 100)) { 627 minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true); 628 update = true; 629 } 630 631 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]); 632 if (rate2->attempts > 30 && 633 MINSTREL_FRAC(rate2->success, rate2->attempts) < 634 MINSTREL_FRAC(20, 100)) { 635 minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false); 636 update = true; 637 } 638 639 if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) { 640 update = true; 641 minstrel_ht_update_stats(mp, mi); 642 if (!(info->flags & IEEE80211_TX_CTL_AMPDU) && 643 mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) 644 minstrel_aggr_check(sta, skb); 645 } 646 647 if (update) 648 minstrel_ht_update_rates(mp, mi); 649 } 650 651 static void 652 minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 653 int index) 654 { 655 struct minstrel_rate_stats *mr; 656 const struct mcs_group *group; 657 unsigned int tx_time, tx_time_rtscts, tx_time_data; 658 unsigned int cw = mp->cw_min; 659 unsigned int ctime = 0; 660 unsigned int t_slot = 9; /* FIXME */ 661 unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len); 662 unsigned int overhead = 0, overhead_rtscts = 0; 663 664 mr = minstrel_get_ratestats(mi, index); 665 if (mr->probability < MINSTREL_FRAC(1, 10)) { 666 mr->retry_count = 1; 667 mr->retry_count_rtscts = 1; 668 return; 669 } 670 671 mr->retry_count = 2; 672 mr->retry_count_rtscts = 2; 673 mr->retry_updated = true; 674 675 group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 676 tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000; 677 678 /* Contention time for first 2 tries */ 679 ctime = (t_slot * cw) >> 1; 680 cw = min((cw << 1) | 1, mp->cw_max); 681 ctime += (t_slot * cw) >> 1; 682 cw = min((cw << 1) | 1, mp->cw_max); 683 684 if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) { 685 overhead = mi->overhead; 686 overhead_rtscts = mi->overhead_rtscts; 687 } 688 689 /* Total TX time for data and Contention after first 2 tries */ 690 tx_time = ctime + 2 * (overhead + tx_time_data); 691 tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data); 692 693 /* See how many more tries we can fit inside segment size */ 694 do { 695 /* Contention time for this try */ 696 ctime = (t_slot * cw) >> 1; 697 cw = min((cw << 1) | 1, mp->cw_max); 698 699 /* Total TX time after this try */ 700 tx_time += ctime + overhead + tx_time_data; 701 tx_time_rtscts += ctime + overhead_rtscts + tx_time_data; 702 703 if (tx_time_rtscts < mp->segment_size) 704 mr->retry_count_rtscts++; 705 } while ((tx_time < mp->segment_size) && 706 (++mr->retry_count < mp->max_retry)); 707 } 708 709 710 static void 711 minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 712 struct ieee80211_sta_rates *ratetbl, int offset, int index) 713 { 714 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 715 struct minstrel_rate_stats *mr; 716 u8 idx; 717 u16 flags; 718 719 mr = minstrel_get_ratestats(mi, index); 720 if (!mr->retry_updated) 721 minstrel_calc_retransmit(mp, mi, index); 722 723 if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) { 724 ratetbl->rate[offset].count = 2; 725 ratetbl->rate[offset].count_rts = 2; 726 ratetbl->rate[offset].count_cts = 2; 727 } else { 728 ratetbl->rate[offset].count = mr->retry_count; 729 ratetbl->rate[offset].count_cts = mr->retry_count; 730 ratetbl->rate[offset].count_rts = mr->retry_count_rtscts; 731 } 732 733 if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) { 734 idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)]; 735 flags = 0; 736 } else { 737 idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8; 738 flags = IEEE80211_TX_RC_MCS | group->flags; 739 } 740 741 if (offset > 0) { 742 ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts; 743 flags |= IEEE80211_TX_RC_USE_RTS_CTS; 744 } 745 746 ratetbl->rate[offset].idx = idx; 747 ratetbl->rate[offset].flags = flags; 748 } 749 750 static void 751 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 752 { 753 struct ieee80211_sta_rates *rates; 754 int i = 0; 755 756 rates = kzalloc(sizeof(*rates), GFP_ATOMIC); 757 if (!rates) 758 return; 759 760 /* Start with max_tp_rate[0] */ 761 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]); 762 763 if (mp->hw->max_rates >= 3) { 764 /* At least 3 tx rates supported, use max_tp_rate[1] next */ 765 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]); 766 } 767 768 if (mp->hw->max_rates >= 2) { 769 /* 770 * At least 2 tx rates supported, use max_prob_rate next */ 771 minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate); 772 } 773 774 rates->rate[i].idx = -1; 775 rate_control_set_rates(mp->hw, mi->sta, rates); 776 } 777 778 static inline int 779 minstrel_get_duration(int index) 780 { 781 const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; 782 return group->duration[index % MCS_GROUP_RATES]; 783 } 784 785 static int 786 minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 787 { 788 struct minstrel_rate_stats *mr; 789 struct minstrel_mcs_group_data *mg; 790 unsigned int sample_dur, sample_group, cur_max_tp_streams; 791 int sample_idx = 0; 792 793 if (mi->sample_wait > 0) { 794 mi->sample_wait--; 795 return -1; 796 } 797 798 if (!mi->sample_tries) 799 return -1; 800 801 sample_group = mi->sample_group; 802 mg = &mi->groups[sample_group]; 803 sample_idx = sample_table[mg->column][mg->index]; 804 minstrel_next_sample_idx(mi); 805 806 if (!(mg->supported & BIT(sample_idx))) 807 return -1; 808 809 mr = &mg->rates[sample_idx]; 810 sample_idx += sample_group * MCS_GROUP_RATES; 811 812 /* 813 * Sampling might add some overhead (RTS, no aggregation) 814 * to the frame. Hence, don't use sampling for the currently 815 * used rates. 816 */ 817 if (sample_idx == mi->max_tp_rate[0] || 818 sample_idx == mi->max_tp_rate[1] || 819 sample_idx == mi->max_prob_rate) 820 return -1; 821 822 /* 823 * Do not sample if the probability is already higher than 95% 824 * to avoid wasting airtime. 825 */ 826 if (mr->probability > MINSTREL_FRAC(95, 100)) 827 return -1; 828 829 /* 830 * Make sure that lower rates get sampled only occasionally, 831 * if the link is working perfectly. 832 */ 833 834 cur_max_tp_streams = minstrel_mcs_groups[mi->max_tp_rate[0] / 835 MCS_GROUP_RATES].streams; 836 sample_dur = minstrel_get_duration(sample_idx); 837 if (sample_dur >= minstrel_get_duration(mi->max_tp_rate[1]) && 838 (cur_max_tp_streams - 1 < 839 minstrel_mcs_groups[sample_group].streams || 840 sample_dur >= minstrel_get_duration(mi->max_prob_rate))) { 841 if (mr->sample_skipped < 20) 842 return -1; 843 844 if (mi->sample_slow++ > 2) 845 return -1; 846 } 847 mi->sample_tries--; 848 849 return sample_idx; 850 } 851 852 static void 853 minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp, 854 struct minstrel_ht_sta *mi, bool val) 855 { 856 u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported; 857 858 if (!supported || !mi->cck_supported_short) 859 return; 860 861 if (supported & (mi->cck_supported_short << (val * 4))) 862 return; 863 864 supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4); 865 mi->groups[MINSTREL_CCK_GROUP].supported = supported; 866 } 867 868 static void 869 minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, 870 struct ieee80211_tx_rate_control *txrc) 871 { 872 const struct mcs_group *sample_group; 873 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); 874 struct ieee80211_tx_rate *rate = &info->status.rates[0]; 875 struct minstrel_ht_sta_priv *msp = priv_sta; 876 struct minstrel_ht_sta *mi = &msp->ht; 877 struct minstrel_priv *mp = priv; 878 int sample_idx; 879 880 if (rate_control_send_low(sta, priv_sta, txrc)) 881 return; 882 883 if (!msp->is_ht) 884 return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc); 885 886 info->flags |= mi->tx_flags; 887 minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble); 888 889 #ifdef CONFIG_MAC80211_DEBUGFS 890 if (mp->fixed_rate_idx != -1) 891 return; 892 #endif 893 894 /* Don't use EAPOL frames for sampling on non-mrr hw */ 895 if (mp->hw->max_rates == 1 && 896 (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO)) 897 sample_idx = -1; 898 else 899 sample_idx = minstrel_get_sample_rate(mp, mi); 900 901 mi->total_packets++; 902 903 /* wraparound */ 904 if (mi->total_packets == ~0) { 905 mi->total_packets = 0; 906 mi->sample_packets = 0; 907 } 908 909 if (sample_idx < 0) 910 return; 911 912 sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES]; 913 info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; 914 rate->count = 1; 915 916 if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) { 917 int idx = sample_idx % ARRAY_SIZE(mp->cck_rates); 918 rate->idx = mp->cck_rates[idx]; 919 rate->flags = 0; 920 return; 921 } 922 923 rate->idx = sample_idx % MCS_GROUP_RATES + 924 (sample_group->streams - 1) * 8; 925 rate->flags = IEEE80211_TX_RC_MCS | sample_group->flags; 926 } 927 928 static void 929 minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 930 struct ieee80211_supported_band *sband, 931 struct ieee80211_sta *sta) 932 { 933 int i; 934 935 if (sband->band != IEEE80211_BAND_2GHZ) 936 return; 937 938 if (!(mp->hw->flags & IEEE80211_HW_SUPPORTS_HT_CCK_RATES)) 939 return; 940 941 mi->cck_supported = 0; 942 mi->cck_supported_short = 0; 943 for (i = 0; i < 4; i++) { 944 if (!rate_supported(sta, sband->band, mp->cck_rates[i])) 945 continue; 946 947 mi->cck_supported |= BIT(i); 948 if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE) 949 mi->cck_supported_short |= BIT(i); 950 } 951 952 mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported; 953 } 954 955 static void 956 minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, 957 struct cfg80211_chan_def *chandef, 958 struct ieee80211_sta *sta, void *priv_sta) 959 { 960 struct minstrel_priv *mp = priv; 961 struct minstrel_ht_sta_priv *msp = priv_sta; 962 struct minstrel_ht_sta *mi = &msp->ht; 963 struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs; 964 u16 sta_cap = sta->ht_cap.cap; 965 int n_supported = 0; 966 int ack_dur; 967 int stbc; 968 int i; 969 970 /* fall back to the old minstrel for legacy stations */ 971 if (!sta->ht_cap.ht_supported) 972 goto use_legacy; 973 974 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != 975 MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1); 976 977 msp->is_ht = true; 978 memset(mi, 0, sizeof(*mi)); 979 980 mi->sta = sta; 981 mi->stats_update = jiffies; 982 983 ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0); 984 mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0); 985 mi->overhead += ack_dur; 986 mi->overhead_rtscts = mi->overhead + 2 * ack_dur; 987 988 mi->avg_ampdu_len = MINSTREL_FRAC(1, 1); 989 990 /* When using MRR, sample more on the first attempt, without delay */ 991 if (mp->has_mrr) { 992 mi->sample_count = 16; 993 mi->sample_wait = 0; 994 } else { 995 mi->sample_count = 8; 996 mi->sample_wait = 8; 997 } 998 mi->sample_tries = 4; 999 1000 stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >> 1001 IEEE80211_HT_CAP_RX_STBC_SHIFT; 1002 mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT; 1003 1004 if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING) 1005 mi->tx_flags |= IEEE80211_TX_CTL_LDPC; 1006 1007 for (i = 0; i < ARRAY_SIZE(mi->groups); i++) { 1008 mi->groups[i].supported = 0; 1009 if (i == MINSTREL_CCK_GROUP) { 1010 minstrel_ht_update_cck(mp, mi, sband, sta); 1011 continue; 1012 } 1013 1014 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) { 1015 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH) { 1016 if (!(sta_cap & IEEE80211_HT_CAP_SGI_40)) 1017 continue; 1018 } else { 1019 if (!(sta_cap & IEEE80211_HT_CAP_SGI_20)) 1020 continue; 1021 } 1022 } 1023 1024 if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH && 1025 sta->bandwidth < IEEE80211_STA_RX_BW_40) 1026 continue; 1027 1028 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */ 1029 if (sta->smps_mode == IEEE80211_SMPS_STATIC && 1030 minstrel_mcs_groups[i].streams > 1) 1031 continue; 1032 1033 mi->groups[i].supported = 1034 mcs->rx_mask[minstrel_mcs_groups[i].streams - 1]; 1035 1036 if (mi->groups[i].supported) 1037 n_supported++; 1038 } 1039 1040 if (!n_supported) 1041 goto use_legacy; 1042 1043 /* create an initial rate table with the lowest supported rates */ 1044 minstrel_ht_update_stats(mp, mi); 1045 minstrel_ht_update_rates(mp, mi); 1046 1047 return; 1048 1049 use_legacy: 1050 msp->is_ht = false; 1051 memset(&msp->legacy, 0, sizeof(msp->legacy)); 1052 msp->legacy.r = msp->ratelist; 1053 msp->legacy.sample_table = msp->sample_table; 1054 return mac80211_minstrel.rate_init(priv, sband, chandef, sta, 1055 &msp->legacy); 1056 } 1057 1058 static void 1059 minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband, 1060 struct cfg80211_chan_def *chandef, 1061 struct ieee80211_sta *sta, void *priv_sta) 1062 { 1063 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta); 1064 } 1065 1066 static void 1067 minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband, 1068 struct cfg80211_chan_def *chandef, 1069 struct ieee80211_sta *sta, void *priv_sta, 1070 u32 changed) 1071 { 1072 minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta); 1073 } 1074 1075 static void * 1076 minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp) 1077 { 1078 struct ieee80211_supported_band *sband; 1079 struct minstrel_ht_sta_priv *msp; 1080 struct minstrel_priv *mp = priv; 1081 struct ieee80211_hw *hw = mp->hw; 1082 int max_rates = 0; 1083 int i; 1084 1085 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 1086 sband = hw->wiphy->bands[i]; 1087 if (sband && sband->n_bitrates > max_rates) 1088 max_rates = sband->n_bitrates; 1089 } 1090 1091 msp = kzalloc(sizeof(*msp), gfp); 1092 if (!msp) 1093 return NULL; 1094 1095 msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp); 1096 if (!msp->ratelist) 1097 goto error; 1098 1099 msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp); 1100 if (!msp->sample_table) 1101 goto error1; 1102 1103 return msp; 1104 1105 error1: 1106 kfree(msp->ratelist); 1107 error: 1108 kfree(msp); 1109 return NULL; 1110 } 1111 1112 static void 1113 minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta) 1114 { 1115 struct minstrel_ht_sta_priv *msp = priv_sta; 1116 1117 kfree(msp->sample_table); 1118 kfree(msp->ratelist); 1119 kfree(msp); 1120 } 1121 1122 static void * 1123 minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) 1124 { 1125 return mac80211_minstrel.alloc(hw, debugfsdir); 1126 } 1127 1128 static void 1129 minstrel_ht_free(void *priv) 1130 { 1131 mac80211_minstrel.free(priv); 1132 } 1133 1134 static u32 minstrel_ht_get_expected_throughput(void *priv_sta) 1135 { 1136 struct minstrel_ht_sta_priv *msp = priv_sta; 1137 struct minstrel_ht_sta *mi = &msp->ht; 1138 int i, j; 1139 1140 if (!msp->is_ht) 1141 return mac80211_minstrel.get_expected_throughput(priv_sta); 1142 1143 i = mi->max_tp_rate[0] / MCS_GROUP_RATES; 1144 j = mi->max_tp_rate[0] % MCS_GROUP_RATES; 1145 1146 /* convert cur_tp from pkt per second in kbps */ 1147 return mi->groups[i].rates[j].cur_tp * AVG_PKT_SIZE * 8 / 1024; 1148 } 1149 1150 static const struct rate_control_ops mac80211_minstrel_ht = { 1151 .name = "minstrel_ht", 1152 .tx_status = minstrel_ht_tx_status, 1153 .get_rate = minstrel_ht_get_rate, 1154 .rate_init = minstrel_ht_rate_init, 1155 .rate_update = minstrel_ht_rate_update, 1156 .alloc_sta = minstrel_ht_alloc_sta, 1157 .free_sta = minstrel_ht_free_sta, 1158 .alloc = minstrel_ht_alloc, 1159 .free = minstrel_ht_free, 1160 #ifdef CONFIG_MAC80211_DEBUGFS 1161 .add_sta_debugfs = minstrel_ht_add_sta_debugfs, 1162 .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs, 1163 #endif 1164 .get_expected_throughput = minstrel_ht_get_expected_throughput, 1165 }; 1166 1167 1168 static void __init init_sample_table(void) 1169 { 1170 int col, i, new_idx; 1171 u8 rnd[MCS_GROUP_RATES]; 1172 1173 memset(sample_table, 0xff, sizeof(sample_table)); 1174 for (col = 0; col < SAMPLE_COLUMNS; col++) { 1175 prandom_bytes(rnd, sizeof(rnd)); 1176 for (i = 0; i < MCS_GROUP_RATES; i++) { 1177 new_idx = (i + rnd[i]) % MCS_GROUP_RATES; 1178 while (sample_table[col][new_idx] != 0xff) 1179 new_idx = (new_idx + 1) % MCS_GROUP_RATES; 1180 1181 sample_table[col][new_idx] = i; 1182 } 1183 } 1184 } 1185 1186 int __init 1187 rc80211_minstrel_ht_init(void) 1188 { 1189 init_sample_table(); 1190 return ieee80211_rate_control_register(&mac80211_minstrel_ht); 1191 } 1192 1193 void 1194 rc80211_minstrel_ht_exit(void) 1195 { 1196 ieee80211_rate_control_unregister(&mac80211_minstrel_ht); 1197 } 1198