rc80211_minstrel_ht.c 36.7 KB
Newer Older
1
/*
2
 * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>
3 4 5 6 7 8 9 10 11 12
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/netdevice.h>
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/debugfs.h>
#include <linux/random.h>
13
#include <linux/moduleparam.h>
14 15 16 17 18 19 20 21 22 23 24 25
#include <linux/ieee80211.h>
#include <net/mac80211.h>
#include "rate.h"
#include "rc80211_minstrel.h"
#include "rc80211_minstrel_ht.h"

#define AVG_PKT_SIZE	1200

/* Number of bits for an average sized packet */
#define MCS_NBITS (AVG_PKT_SIZE << 3)

/* Number of symbols for a packet with (bps) bits per symbol */
26
#define MCS_NSYMS(bps) DIV_ROUND_UP(MCS_NBITS, (bps))
27

28
/* Transmission time (nanoseconds) for a packet containing (syms) symbols */
29 30
#define MCS_SYMBOL_TIME(sgi, syms)					\
	(sgi ?								\
31 32
	  ((syms) * 18000 + 4000) / 5 :	/* syms * 3.6 us */		\
	  ((syms) * 1000) << 2		/* syms * 4 us */		\
33 34 35 36 37
	)

/* Transmit duration for the raw data part of an average sized packet */
#define MCS_DURATION(streams, sgi, bps) MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps)))

38 39
#define BW_20			0
#define BW_40			1
40
#define BW_80			2
41

42 43 44 45
/*
 * Define group sort order: HT40 -> SGI -> #streams
 */
#define GROUP_IDX(_streams, _sgi, _ht40)	\
46
	MINSTREL_HT_GROUP_0 +			\
47
	MINSTREL_MAX_STREAMS * 2 * _ht40 +	\
48
	MINSTREL_MAX_STREAMS * _sgi +	\
49 50
	_streams - 1

51
/* MCS rate information for an MCS group */
52 53
#define MCS_GROUP(_streams, _sgi, _ht40)				\
	[GROUP_IDX(_streams, _sgi, _ht40)] = {				\
54 55
	.streams = _streams,						\
	.flags =							\
56
		IEEE80211_TX_RC_MCS |					\
57 58 59 60 61 62 63 64 65 66 67 68 69 70
		(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |			\
		(_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),		\
	.duration = {							\
		MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26),		\
		MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52),		\
		MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78),		\
		MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104),	\
		MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156),	\
		MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208),	\
		MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234),	\
		MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260)		\
	}								\
}

71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111
#define VHT_GROUP_IDX(_streams, _sgi, _bw)				\
	(MINSTREL_VHT_GROUP_0 +						\
	 MINSTREL_MAX_STREAMS * 2 * (_bw) +				\
	 MINSTREL_MAX_STREAMS * (_sgi) +				\
	 (_streams) - 1)

#define BW2VBPS(_bw, r3, r2, r1)					\
	(_bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)

#define VHT_GROUP(_streams, _sgi, _bw)					\
	[VHT_GROUP_IDX(_streams, _sgi, _bw)] = {			\
	.streams = _streams,						\
	.flags =							\
		IEEE80211_TX_RC_VHT_MCS |				\
		(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |			\
		(_bw == BW_80 ? IEEE80211_TX_RC_80_MHZ_WIDTH :		\
		 _bw == BW_40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),	\
	.duration = {							\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw,  117,  54,  26)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw,  234, 108,  52)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw,  351, 162,  78)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw,  468, 216, 104)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw,  702, 324, 156)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw,  936, 432, 208)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw, 1053, 486, 234)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw, 1170, 540, 260)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw, 1404, 648, 312)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw, 1560, 720, 346))		\
	}								\
}

112
#define CCK_DURATION(_bitrate, _short, _len)		\
113
	(1000 * (10 /* SIFS */ +			\
Weilong Chen's avatar
Weilong Chen committed
114
	 (_short ? 72 + 24 : 144 + 48) +		\
115
	 (8 * (_len + 4) * 10) / (_bitrate)))
116 117 118 119 120 121 122 123 124 125 126

#define CCK_ACK_DURATION(_bitrate, _short)			\
	(CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) +	\
	 CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))

#define CCK_DURATION_LIST(_short)			\
	CCK_ACK_DURATION(10, _short),			\
	CCK_ACK_DURATION(20, _short),			\
	CCK_ACK_DURATION(55, _short),			\
	CCK_ACK_DURATION(110, _short)

127 128 129
#define CCK_GROUP					\
	[MINSTREL_CCK_GROUP] = {			\
		.streams = 0,				\
130
		.flags = 0,				\
131 132 133 134
		.duration = {				\
			CCK_DURATION_LIST(false),	\
			CCK_DURATION_LIST(true)		\
		}					\
135 136
	}

137 138 139 140 141 142 143
#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
static bool minstrel_vht_only = true;
module_param(minstrel_vht_only, bool, 0644);
MODULE_PARM_DESC(minstrel_vht_only,
		 "Use only VHT rates when VHT is supported by sta.");
#endif

144 145 146 147
/*
 * To enable sufficiently targeted rate sampling, MCS rates are divided into
 * groups, based on the number of streams and flags (HT40, SGI) that they
 * use.
148 149
 *
 * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
150
 * BW -> SGI -> #streams
151 152
 */
const struct mcs_group minstrel_mcs_groups[] = {
153 154
	MCS_GROUP(1, 0, BW_20),
	MCS_GROUP(2, 0, BW_20),
155
#if MINSTREL_MAX_STREAMS >= 3
156
	MCS_GROUP(3, 0, BW_20),
157 158
#endif

159 160
	MCS_GROUP(1, 1, BW_20),
	MCS_GROUP(2, 1, BW_20),
161
#if MINSTREL_MAX_STREAMS >= 3
162
	MCS_GROUP(3, 1, BW_20),
163 164
#endif

165 166
	MCS_GROUP(1, 0, BW_40),
	MCS_GROUP(2, 0, BW_40),
167
#if MINSTREL_MAX_STREAMS >= 3
168
	MCS_GROUP(3, 0, BW_40),
169 170
#endif

171 172
	MCS_GROUP(1, 1, BW_40),
	MCS_GROUP(2, 1, BW_40),
173
#if MINSTREL_MAX_STREAMS >= 3
174
	MCS_GROUP(3, 1, BW_40),
175
#endif
176

177 178 179 180 181 182 183 184 185 186 187 188 189 190
	CCK_GROUP,

#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
	VHT_GROUP(1, 0, BW_20),
	VHT_GROUP(2, 0, BW_20),
#if MINSTREL_MAX_STREAMS >= 3
	VHT_GROUP(3, 0, BW_20),
#endif

	VHT_GROUP(1, 1, BW_20),
	VHT_GROUP(2, 1, BW_20),
#if MINSTREL_MAX_STREAMS >= 3
	VHT_GROUP(3, 1, BW_20),
#endif
191

192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216
	VHT_GROUP(1, 0, BW_40),
	VHT_GROUP(2, 0, BW_40),
#if MINSTREL_MAX_STREAMS >= 3
	VHT_GROUP(3, 0, BW_40),
#endif

	VHT_GROUP(1, 1, BW_40),
	VHT_GROUP(2, 1, BW_40),
#if MINSTREL_MAX_STREAMS >= 3
	VHT_GROUP(3, 1, BW_40),
#endif

	VHT_GROUP(1, 0, BW_80),
	VHT_GROUP(2, 0, BW_80),
#if MINSTREL_MAX_STREAMS >= 3
	VHT_GROUP(3, 0, BW_80),
#endif

	VHT_GROUP(1, 1, BW_80),
	VHT_GROUP(2, 1, BW_80),
#if MINSTREL_MAX_STREAMS >= 3
	VHT_GROUP(3, 1, BW_80),
#endif
#endif
};
217

218
static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
219

220 221 222
static void
minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);

223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261
/*
 * Some VHT MCSes are invalid (when Ndbps / Nes is not an integer)
 * e.g for MCS9@20MHzx1Nss: Ndbps=8x52*(5/6) Nes=1
 *
 * Returns the valid mcs map for struct minstrel_mcs_group_data.supported
 */
static u16
minstrel_get_valid_vht_rates(int bw, int nss, __le16 mcs_map)
{
	u16 mask = 0;

	if (bw == BW_20) {
		if (nss != 3 && nss != 6)
			mask = BIT(9);
	} else if (bw == BW_80) {
		if (nss == 3 || nss == 7)
			mask = BIT(6);
		else if (nss == 6)
			mask = BIT(9);
	} else {
		WARN_ON(bw != BW_40);
	}

	switch ((le16_to_cpu(mcs_map) >> (2 * (nss - 1))) & 3) {
	case IEEE80211_VHT_MCS_SUPPORT_0_7:
		mask |= 0x300;
		break;
	case IEEE80211_VHT_MCS_SUPPORT_0_8:
		mask |= 0x200;
		break;
	case IEEE80211_VHT_MCS_SUPPORT_0_9:
		break;
	default:
		mask = 0x3ff;
	}

	return 0x3ff & ~mask;
}

262 263 264 265 266 267
/*
 * Look up an MCS group index based on mac80211 rate information
 */
static int
minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
{
268
	return GROUP_IDX((rate->idx / 8) + 1,
269 270
			 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
			 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
271 272
}

273 274 275 276 277 278 279 280 281
static int
minstrel_vht_get_group_idx(struct ieee80211_tx_rate *rate)
{
	return VHT_GROUP_IDX(ieee80211_rate_get_vht_nss(rate),
			     !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
			     !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH) +
			     2*!!(rate->flags & IEEE80211_TX_RC_80_MHZ_WIDTH));
}

282 283 284 285 286 287 288 289
static struct minstrel_rate_stats *
minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
		      struct ieee80211_tx_rate *rate)
{
	int group, idx;

	if (rate->flags & IEEE80211_TX_RC_MCS) {
		group = minstrel_ht_get_group_idx(rate);
290
		idx = rate->idx % 8;
291 292 293
	} else if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
		group = minstrel_vht_get_group_idx(rate);
		idx = ieee80211_rate_get_vht_mcs(rate);
294 295 296 297 298 299 300 301 302 303 304 305 306 307
	} else {
		group = MINSTREL_CCK_GROUP;

		for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++)
			if (rate->idx == mp->cck_rates[idx])
				break;

		/* short preamble */
		if (!(mi->groups[group].supported & BIT(idx)))
			idx += 4;
	}
	return &mi->groups[group].rates[idx];
}

308 309 310 311 312 313 314 315 316 317 318
static inline struct minstrel_rate_stats *
minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
{
	return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
}


/*
 * Recalculate success probabilities and counters for a rate using EWMA
 */
static void
319
minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr)
320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344
{
	if (unlikely(mr->attempts > 0)) {
		mr->sample_skipped = 0;
		mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
		if (!mr->att_hist)
			mr->probability = mr->cur_prob;
		else
			mr->probability = minstrel_ewma(mr->probability,
				mr->cur_prob, EWMA_LEVEL);
		mr->att_hist += mr->attempts;
		mr->succ_hist += mr->success;
	} else {
		mr->sample_skipped++;
	}
	mr->last_success = mr->success;
	mr->last_attempts = mr->attempts;
	mr->success = 0;
	mr->attempts = 0;
}

/*
 * Calculate throughput based on the average A-MPDU length, taking into account
 * the expected number of retransmissions and their expected length
 */
static void
345
minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
346 347
{
	struct minstrel_rate_stats *mr;
348 349
	unsigned int nsecs = 0;
	unsigned int tp;
350
	unsigned int prob;
351 352

	mr = &mi->groups[group].rates[rate];
353
	prob = mr->probability;
354

355
	if (prob < MINSTREL_FRAC(1, 10)) {
356 357 358 359
		mr->cur_tp = 0;
		return;
	}

360 361 362 363 364 365 366
	/*
	 * For the throughput calculation, limit the probability value to 90% to
	 * account for collision related packet error rate fluctuation
	 */
	if (prob > MINSTREL_FRAC(9, 10))
		prob = MINSTREL_FRAC(9, 10);

367
	if (group != MINSTREL_CCK_GROUP)
368
		nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
369

370 371
	nsecs += minstrel_mcs_groups[group].duration[rate];

372 373
	/* prob is scaled - see MINSTREL_FRAC above */
	tp = 1000000 * ((prob * 1000) / nsecs);
374
	mr->cur_tp = MINSTREL_TRUNC(tp);
375 376
}

377 378 379 380 381 382 383 384
/*
 * Find & sort topmost throughput rates
 *
 * If multiple rates provide equal throughput the sorting is based on their
 * current success probability. Higher success probability is preferred among
 * MCS groups, CCK rates do not provide aggregation and are therefore at last.
 */
static void
385 386
minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u16 index,
			       u16 *tp_list)
387 388 389 390 391 392 393 394 395 396
{
	int cur_group, cur_idx, cur_thr, cur_prob;
	int tmp_group, tmp_idx, tmp_thr, tmp_prob;
	int j = MAX_THR_RATES;

	cur_group = index / MCS_GROUP_RATES;
	cur_idx = index  % MCS_GROUP_RATES;
	cur_thr = mi->groups[cur_group].rates[cur_idx].cur_tp;
	cur_prob = mi->groups[cur_group].rates[cur_idx].probability;

397
	do {
398 399 400 401
		tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
		tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
		tmp_thr = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
		tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability;
402 403 404 405 406
		if (cur_thr < tmp_thr ||
		    (cur_thr == tmp_thr && cur_prob <= tmp_prob))
			break;
		j--;
	} while (j > 0);
407 408 409 410 411 412 413 414 415 416 417 418 419

	if (j < MAX_THR_RATES - 1) {
		memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) *
		       (MAX_THR_RATES - (j + 1))));
	}
	if (j < MAX_THR_RATES)
		tp_list[j] = index;
}

/*
 * Find and set the topmost probability rate per sta and per group
 */
static void
420
minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 index)
421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462
{
	struct minstrel_mcs_group_data *mg;
	struct minstrel_rate_stats *mr;
	int tmp_group, tmp_idx, tmp_tp, tmp_prob, max_tp_group;

	mg = &mi->groups[index / MCS_GROUP_RATES];
	mr = &mg->rates[index % MCS_GROUP_RATES];

	tmp_group = mi->max_prob_rate / MCS_GROUP_RATES;
	tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES;
	tmp_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability;

	/* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
	 * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
	max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES;
	if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) &&
	    (max_tp_group != MINSTREL_CCK_GROUP))
		return;

	if (mr->probability > MINSTREL_FRAC(75, 100)) {
		if (mr->cur_tp > tmp_tp)
			mi->max_prob_rate = index;
		if (mr->cur_tp > mg->rates[mg->max_group_prob_rate].cur_tp)
			mg->max_group_prob_rate = index;
	} else {
		if (mr->probability > tmp_prob)
			mi->max_prob_rate = index;
		if (mr->probability > mg->rates[mg->max_group_prob_rate].probability)
			mg->max_group_prob_rate = index;
	}
}


/*
 * Assign new rate set per sta and use CCK rates only if the fastest
 * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted
 * rate sets where MCS and CCK rates are mixed, because CCK rates can
 * not use aggregation.
 */
static void
minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi,
463 464
				 u16 tmp_mcs_tp_rate[MAX_THR_RATES],
				 u16 tmp_cck_tp_rate[MAX_THR_RATES])
465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512
{
	unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp;
	int i;

	tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES;
	tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES;
	tmp_cck_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;

	tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES;
	tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES;
	tmp_mcs_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;

	if (tmp_cck_tp > tmp_mcs_tp) {
		for(i = 0; i < MAX_THR_RATES; i++) {
			minstrel_ht_sort_best_tp_rates(mi, tmp_cck_tp_rate[i],
						       tmp_mcs_tp_rate);
		}
	}

}

/*
 * Try to increase robustness of max_prob rate by decrease number of
 * streams if possible.
 */
static inline void
minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
{
	struct minstrel_mcs_group_data *mg;
	struct minstrel_rate_stats *mr;
	int tmp_max_streams, group;
	int tmp_tp = 0;

	tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
			  MCS_GROUP_RATES].streams;
	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
		mg = &mi->groups[group];
		if (!mg->supported || group == MINSTREL_CCK_GROUP)
			continue;
		mr = minstrel_get_ratestats(mi, mg->max_group_prob_rate);
		if (tmp_tp < mr->cur_tp &&
		   (minstrel_mcs_groups[group].streams < tmp_max_streams)) {
				mi->max_prob_rate = mg->max_group_prob_rate;
				tmp_tp = mr->cur_tp;
		}
	}
}

513 514 515 516 517 518
/*
 * Update rate statistics and select new primary rates
 *
 * Rules for rate selection:
 *  - max_prob_rate must use only one stream, as a tradeoff between delivery
 *    probability and throughput during strong fluctuations
519
 *  - as long as the max prob rate has a probability of more than 75%, pick
520 521 522 523 524 525 526
 *    higher throughput rates, even if the probablity is a bit lower
 */
static void
minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
{
	struct minstrel_mcs_group_data *mg;
	struct minstrel_rate_stats *mr;
527
	int group, i, j;
528 529
	u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
	u16 tmp_cck_tp_rate[MAX_THR_RATES], index;
530 531 532 533 534 535 536 537 538 539 540

	if (mi->ampdu_packets > 0) {
		mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
			MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
		mi->ampdu_len = 0;
		mi->ampdu_packets = 0;
	}

	mi->sample_slow = 0;
	mi->sample_count = 0;

541 542 543 544 545
	/* Initialize global rate indexes */
	for(j = 0; j < MAX_THR_RATES; j++){
		tmp_mcs_tp_rate[j] = 0;
		tmp_cck_tp_rate[j] = 0;
	}
546

547 548
	/* Find best rate sets within all MCS groups*/
	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
549 550 551 552 553 554 555

		mg = &mi->groups[group];
		if (!mg->supported)
			continue;

		mi->sample_count++;

556 557 558 559
		/* (re)Initialize group rate indexes */
		for(j = 0; j < MAX_THR_RATES; j++)
			tmp_group_tp_rate[j] = group;

560 561 562 563
		for (i = 0; i < MCS_GROUP_RATES; i++) {
			if (!(mg->supported & BIT(i)))
				continue;

564 565
			index = MCS_GROUP_RATES * group + i;

566 567
			mr = &mg->rates[i];
			mr->retry_updated = false;
568 569
			minstrel_calc_rate_ewma(mr);
			minstrel_ht_calc_tp(mi, group, i);
570 571 572 573

			if (!mr->cur_tp)
				continue;

574 575 576 577 578 579 580
			/* Find max throughput rate set */
			if (group != MINSTREL_CCK_GROUP) {
				minstrel_ht_sort_best_tp_rates(mi, index,
							       tmp_mcs_tp_rate);
			} else if (group == MINSTREL_CCK_GROUP) {
				minstrel_ht_sort_best_tp_rates(mi, index,
							       tmp_cck_tp_rate);
581 582
			}

583 584 585
			/* Find max throughput rate set within a group */
			minstrel_ht_sort_best_tp_rates(mi, index,
						       tmp_group_tp_rate);
586

587 588
			/* Find max probability rate per group and global */
			minstrel_ht_set_best_prob_rate(mi, index);
589 590
		}

591 592
		memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
		       sizeof(mg->max_group_tp_rate));
593 594
	}

595 596 597
	/* Assign new rate set per sta */
	minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate);
	memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));
598

599 600 601 602 603
	/* Try to increase robustness of max_prob_rate*/
	minstrel_ht_prob_rate_reduce_streams(mi);

	/* try to sample all available rates during each interval */
	mi->sample_count *= 8;
604

605 606 607
#ifdef CONFIG_MAC80211_DEBUGFS
	/* use fixed index if set */
	if (mp->fixed_rate_idx != -1) {
608 609
		for (i = 0; i < 4; i++)
			mi->max_tp_rate[i] = mp->fixed_rate_idx;
610 611 612
		mi->max_prob_rate = mp->fixed_rate_idx;
	}
#endif
613

614
	/* Reset update timer */
615 616 617 618
	mi->stats_update = jiffies;
}

static bool
619
minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
620
{
621
	if (rate->idx < 0)
622 623
		return false;

624
	if (!rate->count)
625 626
		return false;

627 628
	if (rate->flags & IEEE80211_TX_RC_MCS ||
	    rate->flags & IEEE80211_TX_RC_VHT_MCS)
629 630 631 632 633 634
		return true;

	return rate->idx == mp->cck_rates[0] ||
	       rate->idx == mp->cck_rates[1] ||
	       rate->idx == mp->cck_rates[2] ||
	       rate->idx == mp->cck_rates[3];
635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659
}

static void
minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
{
	struct minstrel_mcs_group_data *mg;

	for (;;) {
		mi->sample_group++;
		mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
		mg = &mi->groups[mi->sample_group];

		if (!mg->supported)
			continue;

		if (++mg->index >= MCS_GROUP_RATES) {
			mg->index = 0;
			if (++mg->column >= ARRAY_SIZE(sample_table))
				mg->column = 0;
		}
		break;
	}
}

static void
660
minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u16 *idx, bool primary)
661 662 663 664 665 666 667 668 669 670 671 672 673 674 675
{
	int group, orig_group;

	orig_group = group = *idx / MCS_GROUP_RATES;
	while (group > 0) {
		group--;

		if (!mi->groups[group].supported)
			continue;

		if (minstrel_mcs_groups[group].streams >
		    minstrel_mcs_groups[orig_group].streams)
			continue;

		if (primary)
676
			*idx = mi->groups[group].max_group_tp_rate[0];
677
		else
678
			*idx = mi->groups[group].max_group_tp_rate[1];
679 680 681 682 683
		break;
	}
}

static void
684
minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
685 686 687 688 689
{
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
	u16 tid;

690 691 692
	if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
		return;

693 694 695
	if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
		return;

696
	if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
697 698 699
		return;

	tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
700
	if (likely(sta->ampdu_mlme.tid_tx[tid]))
701 702
		return;

703
	ieee80211_start_tx_ba_session(pubsta, tid, 5000);
704 705 706 707 708
}

static void
minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
                      struct ieee80211_sta *sta, void *priv_sta,
709
                      struct ieee80211_tx_info *info)
710 711 712 713 714 715
{
	struct minstrel_ht_sta_priv *msp = priv_sta;
	struct minstrel_ht_sta *mi = &msp->ht;
	struct ieee80211_tx_rate *ar = info->status.rates;
	struct minstrel_rate_stats *rate, *rate2;
	struct minstrel_priv *mp = priv;
716
	bool last, update = false;
717
	int i;
718 719

	if (!msp->is_ht)
720 721
		return mac80211_minstrel.tx_status_noskb(priv, sband, sta,
							 &msp->legacy, info);
722 723 724 725 726 727

	/* This packet was aggregated but doesn't carry status info */
	if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
	    !(info->flags & IEEE80211_TX_STAT_AMPDU))
		return;

728 729 730
	if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
		info->status.ampdu_ack_len =
			(info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
731 732 733 734 735 736 737
		info->status.ampdu_len = 1;
	}

	mi->ampdu_packets++;
	mi->ampdu_len += info->status.ampdu_len;

	if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
738
		mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
739
		mi->sample_tries = 1;
740 741 742
		mi->sample_count--;
	}

743
	if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
744 745
		mi->sample_packets += info->status.ampdu_len;

746
	last = !minstrel_ht_txstat_valid(mp, &ar[0]);
747 748
	for (i = 0; !last; i++) {
		last = (i == IEEE80211_TX_MAX_RATES - 1) ||
749
		       !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
750

751
		rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
752

753
		if (last)
754 755 756 757 758 759 760 761 762
			rate->success += info->status.ampdu_ack_len;

		rate->attempts += ar[i].count * info->status.ampdu_len;
	}

	/*
	 * check for sudden death of spatial multiplexing,
	 * downgrade to a lower number of streams if necessary.
	 */
763
	rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
764 765
	if (rate->attempts > 30 &&
	    MINSTREL_FRAC(rate->success, rate->attempts) <
766
	    MINSTREL_FRAC(20, 100)) {
767
		minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
768 769
		update = true;
	}
770

771
	rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
772 773
	if (rate2->attempts > 30 &&
	    MINSTREL_FRAC(rate2->success, rate2->attempts) <
774
	    MINSTREL_FRAC(20, 100)) {
775
		minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
776 777
		update = true;
	}
778 779

	if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
780
		update = true;
781 782
		minstrel_ht_update_stats(mp, mi);
	}
783 784 785

	if (update)
		minstrel_ht_update_rates(mp, mi);
786 787 788 789 790 791 792 793 794 795
}

static void
minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
                         int index)
{
	struct minstrel_rate_stats *mr;
	const struct mcs_group *group;
	unsigned int tx_time, tx_time_rtscts, tx_time_data;
	unsigned int cw = mp->cw_min;
796
	unsigned int ctime = 0;
797 798
	unsigned int t_slot = 9; /* FIXME */
	unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
799
	unsigned int overhead = 0, overhead_rtscts = 0;
800 801 802 803 804 805 806 807 808 809 810 811 812

	mr = minstrel_get_ratestats(mi, index);
	if (mr->probability < MINSTREL_FRAC(1, 10)) {
		mr->retry_count = 1;
		mr->retry_count_rtscts = 1;
		return;
	}

	mr->retry_count = 2;
	mr->retry_count_rtscts = 2;
	mr->retry_updated = true;

	group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
813
	tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
814 815 816 817 818 819 820

	/* Contention time for first 2 tries */
	ctime = (t_slot * cw) >> 1;
	cw = min((cw << 1) | 1, mp->cw_max);
	ctime += (t_slot * cw) >> 1;
	cw = min((cw << 1) | 1, mp->cw_max);

821 822 823 824 825
	if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
		overhead = mi->overhead;
		overhead_rtscts = mi->overhead_rtscts;
	}

826
	/* Total TX time for data and Contention after first 2 tries */
827 828
	tx_time = ctime + 2 * (overhead + tx_time_data);
	tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
829 830

	/* See how many more tries we can fit inside segment size */
831
	do {
832 833 834 835 836
		/* Contention time for this try */
		ctime = (t_slot * cw) >> 1;
		cw = min((cw << 1) | 1, mp->cw_max);

		/* Total TX time after this try */
837 838
		tx_time += ctime + overhead + tx_time_data;
		tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
839

840 841 842 843 844 845 846 847 848
		if (tx_time_rtscts < mp->segment_size)
			mr->retry_count_rtscts++;
	} while ((tx_time < mp->segment_size) &&
	         (++mr->retry_count < mp->max_retry));
}


static void
minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
849
                     struct ieee80211_sta_rates *ratetbl, int offset, int index)
850 851 852
{
	const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
	struct minstrel_rate_stats *mr;
853
	u8 idx;
854
	u16 flags = group->flags;
855 856 857 858 859

	mr = minstrel_get_ratestats(mi, index);
	if (!mr->retry_updated)
		minstrel_calc_retransmit(mp, mi, index);

860 861 862 863 864 865 866 867 868
	if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) {
		ratetbl->rate[offset].count = 2;
		ratetbl->rate[offset].count_rts = 2;
		ratetbl->rate[offset].count_cts = 2;
	} else {
		ratetbl->rate[offset].count = mr->retry_count;
		ratetbl->rate[offset].count_cts = mr->retry_count;
		ratetbl->rate[offset].count_rts = mr->retry_count_rtscts;
	}
869

870
	if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP)
871
		idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
872 873 874
	else if (flags & IEEE80211_TX_RC_VHT_MCS)
		idx = ((group->streams - 1) << 4) |
		      ((index % MCS_GROUP_RATES) & 0xF);
875
	else
876
		idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;
877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894

	if (offset > 0) {
		ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
		flags |= IEEE80211_TX_RC_USE_RTS_CTS;
	}

	ratetbl->rate[offset].idx = idx;
	ratetbl->rate[offset].flags = flags;
}

static void
minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
{
	struct ieee80211_sta_rates *rates;
	int i = 0;

	rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
	if (!rates)
895
		return;
896

897 898
	/* Start with max_tp_rate[0] */
	minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
899 900

	if (mp->hw->max_rates >= 3) {
901 902
		/* At least 3 tx rates supported, use max_tp_rate[1] next */
		minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]);
903 904 905 906 907 908
	}

	if (mp->hw->max_rates >= 2) {
		/*
		 * At least 2 tx rates supported, use max_prob_rate next */
		minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
909 910
	}

911 912
	rates->rate[i].idx = -1;
	rate_control_set_rates(mp->hw, mi->sta, rates);
913 914 915 916 917 918 919 920 921 922 923 924 925 926
}

static inline int
minstrel_get_duration(int index)
{
	const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
	return group->duration[index % MCS_GROUP_RATES];
}

static int
minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
{
	struct minstrel_rate_stats *mr;
	struct minstrel_mcs_group_data *mg;
927
	unsigned int sample_dur, sample_group, cur_max_tp_streams;
928 929 930 931 932 933 934 935 936 937
	int sample_idx = 0;

	if (mi->sample_wait > 0) {
		mi->sample_wait--;
		return -1;
	}

	if (!mi->sample_tries)
		return -1;

938 939
	sample_group = mi->sample_group;
	mg = &mi->groups[sample_group];
940
	sample_idx = sample_table[mg->column][mg->index];
941 942 943 944 945
	minstrel_next_sample_idx(mi);

	if (!(mg->supported & BIT(sample_idx)))
		return -1;

946
	mr = &mg->rates[sample_idx];
947
	sample_idx += sample_group * MCS_GROUP_RATES;
948

949 950 951
	/*
	 * Sampling might add some overhead (RTS, no aggregation)
	 * to the frame. Hence, don't use sampling for the currently
952
	 * used rates.
953
	 */
954 955
	if (sample_idx == mi->max_tp_rate[0] ||
	    sample_idx == mi->max_tp_rate[1] ||
956
	    sample_idx == mi->max_prob_rate)
957
		return -1;
958

959
	/*
960 961
	 * Do not sample if the probability is already higher than 95%
	 * to avoid wasting airtime.
962
	 */
963
	if (mr->probability > MINSTREL_FRAC(95, 100))
964
		return -1;
965 966 967 968 969

	/*
	 * Make sure that lower rates get sampled only occasionally,
	 * if the link is working perfectly.
	 */
970 971 972

	cur_max_tp_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
		MCS_GROUP_RATES].streams;
973
	sample_dur = minstrel_get_duration(sample_idx);
974 975
	if (sample_dur >= minstrel_get_duration(mi->max_tp_rate[1]) &&
	    (cur_max_tp_streams - 1 <
976 977
	     minstrel_mcs_groups[sample_group].streams ||
	     sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
978
		if (mr->sample_skipped < 20)
979
			return -1;
980 981

		if (mi->sample_slow++ > 2)
982
			return -1;
983
	}
984
	mi->sample_tries--;
985 986 987 988

	return sample_idx;
}

989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004
static void
minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp,
				    struct minstrel_ht_sta *mi, bool val)
{
	u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported;

	if (!supported || !mi->cck_supported_short)
		return;

	if (supported & (mi->cck_supported_short << (val * 4)))
		return;

	supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4);
	mi->groups[MINSTREL_CCK_GROUP].supported = supported;
}

1005 1006 1007 1008
static void
minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
                     struct ieee80211_tx_rate_control *txrc)
{
1009
	const struct mcs_group *sample_group;
1010
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
1011
	struct ieee80211_tx_rate *rate = &info->status.rates[0];
1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022
	struct minstrel_ht_sta_priv *msp = priv_sta;
	struct minstrel_ht_sta *mi = &msp->ht;
	struct minstrel_priv *mp = priv;
	int sample_idx;

	if (rate_control_send_low(sta, priv_sta, txrc))
		return;

	if (!msp->is_ht)
		return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);

1023 1024 1025 1026
	if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
	    mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
		minstrel_aggr_check(sta, txrc->skb);

1027
	info->flags |= mi->tx_flags;
1028
	minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble);
1029

1030 1031 1032 1033 1034
#ifdef CONFIG_MAC80211_DEBUGFS
	if (mp->fixed_rate_idx != -1)
		return;
#endif

1035 1036
	/* Don't use EAPOL frames for sampling on non-mrr hw */
	if (mp->hw->max_rates == 1 &&
1037
	    (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
1038 1039 1040
		sample_idx = -1;
	else
		sample_idx = minstrel_get_sample_rate(mp, mi);
1041

1042 1043 1044 1045 1046 1047 1048
	mi->total_packets++;

	/* wraparound */
	if (mi->total_packets == ~0) {
		mi->total_packets = 0;
		mi->sample_packets = 0;
	}
1049 1050 1051 1052 1053 1054

	if (sample_idx < 0)
		return;

	sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
	info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
1055 1056 1057 1058 1059
	rate->count = 1;

	if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
		int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
		rate->idx = mp->cck_rates[idx];
1060 1061 1062
	} else if (sample_group->flags & IEEE80211_TX_RC_VHT_MCS) {
		ieee80211_rate_set_vht(rate, sample_idx % MCS_GROUP_RATES,
				       sample_group->streams);
1063 1064 1065
	} else {
		rate->idx = sample_idx % MCS_GROUP_RATES +
			    (sample_group->streams - 1) * 8;
1066 1067
	}

1068
	rate->flags = sample_group->flags;
1069 1070
}

1071 1072 1073 1074 1075 1076 1077 1078 1079 1080
static void
minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
		       struct ieee80211_supported_band *sband,
		       struct ieee80211_sta *sta)
{
	int i;

	if (sband->band != IEEE80211_BAND_2GHZ)
		return;

1081 1082 1083
	if (!(mp->hw->flags & IEEE80211_HW_SUPPORTS_HT_CCK_RATES))
		return;

1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097
	mi->cck_supported = 0;
	mi->cck_supported_short = 0;
	for (i = 0; i < 4; i++) {
		if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
			continue;

		mi->cck_supported |= BIT(i);
		if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
			mi->cck_supported_short |= BIT(i);
	}

	mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported;
}

1098 1099
static void
minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
1100
			struct cfg80211_chan_def *chandef,
1101
                        struct ieee80211_sta *sta, void *priv_sta)
1102 1103 1104 1105 1106 1107
{
	struct minstrel_priv *mp = priv;
	struct minstrel_ht_sta_priv *msp = priv_sta;
	struct minstrel_ht_sta *mi = &msp->ht;
	struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
	u16 sta_cap = sta->ht_cap.cap;