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/moduleparam.h>
  14#include <linux/ieee80211.h>
  15#include <net/mac80211.h>
  16#include "rate.h"
  17#include "rc80211_minstrel.h"
  18#include "rc80211_minstrel_ht.h"
  19
  20#define AVG_AMPDU_SIZE	16
  21#define AVG_PKT_SIZE	1200
  22
  23/* Number of bits for an average sized packet */
  24#define MCS_NBITS ((AVG_PKT_SIZE * AVG_AMPDU_SIZE) << 3)
  25
  26/* Number of symbols for a packet with (bps) bits per symbol */
  27#define MCS_NSYMS(bps) DIV_ROUND_UP(MCS_NBITS, (bps))
  28
  29/* Transmission time (nanoseconds) for a packet containing (syms) symbols */
  30#define MCS_SYMBOL_TIME(sgi, syms)					\
  31	(sgi ?								\
  32	  ((syms) * 18000 + 4000) / 5 :	/* syms * 3.6 us */		\
  33	  ((syms) * 1000) << 2		/* syms * 4 us */		\
  34	)
  35
  36/* Transmit duration for the raw data part of an average sized packet */
  37#define MCS_DURATION(streams, sgi, bps) \
  38	(MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps))) / AVG_AMPDU_SIZE)
  39
  40#define BW_20			0
  41#define BW_40			1
  42#define BW_80			2
  43
  44/*
  45 * Define group sort order: HT40 -> SGI -> #streams
  46 */
  47#define GROUP_IDX(_streams, _sgi, _ht40)	\
  48	MINSTREL_HT_GROUP_0 +			\
  49	MINSTREL_MAX_STREAMS * 2 * _ht40 +	\
  50	MINSTREL_MAX_STREAMS * _sgi +	\
  51	_streams - 1
  52
  53/* MCS rate information for an MCS group */
  54#define MCS_GROUP(_streams, _sgi, _ht40)				\
  55	[GROUP_IDX(_streams, _sgi, _ht40)] = {				\
  56	.streams = _streams,						\
  57	.flags =							\
  58		IEEE80211_TX_RC_MCS |					\
  59		(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |			\
  60		(_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),		\
  61	.duration = {							\
  62		MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26),		\
  63		MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52),		\
  64		MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78),		\
  65		MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104),	\
  66		MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156),	\
  67		MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208),	\
  68		MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234),	\
  69		MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260)		\
  70	}								\
  71}
  72
  73#define VHT_GROUP_IDX(_streams, _sgi, _bw)				\
  74	(MINSTREL_VHT_GROUP_0 +						\
  75	 MINSTREL_MAX_STREAMS * 2 * (_bw) +				\
  76	 MINSTREL_MAX_STREAMS * (_sgi) +				\
  77	 (_streams) - 1)
  78
  79#define BW2VBPS(_bw, r3, r2, r1)					\
  80	(_bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)
  81
  82#define VHT_GROUP(_streams, _sgi, _bw)					\
  83	[VHT_GROUP_IDX(_streams, _sgi, _bw)] = {			\
  84	.streams = _streams,						\
  85	.flags =							\
  86		IEEE80211_TX_RC_VHT_MCS |				\
  87		(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |			\
  88		(_bw == BW_80 ? IEEE80211_TX_RC_80_MHZ_WIDTH :		\
  89		 _bw == BW_40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),	\
  90	.duration = {							\
  91		MCS_DURATION(_streams, _sgi,				\
  92			     BW2VBPS(_bw,  117,  54,  26)),		\
  93		MCS_DURATION(_streams, _sgi,				\
  94			     BW2VBPS(_bw,  234, 108,  52)),		\
  95		MCS_DURATION(_streams, _sgi,				\
  96			     BW2VBPS(_bw,  351, 162,  78)),		\
  97		MCS_DURATION(_streams, _sgi,				\
  98			     BW2VBPS(_bw,  468, 216, 104)),		\
  99		MCS_DURATION(_streams, _sgi,				\
 100			     BW2VBPS(_bw,  702, 324, 156)),		\
 101		MCS_DURATION(_streams, _sgi,				\
 102			     BW2VBPS(_bw,  936, 432, 208)),		\
 103		MCS_DURATION(_streams, _sgi,				\
 104			     BW2VBPS(_bw, 1053, 486, 234)),		\
 105		MCS_DURATION(_streams, _sgi,				\
 106			     BW2VBPS(_bw, 1170, 540, 260)),		\
 107		MCS_DURATION(_streams, _sgi,				\
 108			     BW2VBPS(_bw, 1404, 648, 312)),		\
 109		MCS_DURATION(_streams, _sgi,				\
 110			     BW2VBPS(_bw, 1560, 720, 346))		\
 111	}								\
 112}
 113
 114#define CCK_DURATION(_bitrate, _short, _len)		\
 115	(1000 * (10 /* SIFS */ +			\
 116	 (_short ? 72 + 24 : 144 + 48) +		\
 117	 (8 * (_len + 4) * 10) / (_bitrate)))
 118
 119#define CCK_ACK_DURATION(_bitrate, _short)			\
 120	(CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) +	\
 121	 CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))
 122
 123#define CCK_DURATION_LIST(_short)			\
 124	CCK_ACK_DURATION(10, _short),			\
 125	CCK_ACK_DURATION(20, _short),			\
 126	CCK_ACK_DURATION(55, _short),			\
 127	CCK_ACK_DURATION(110, _short)
 128
 129#define CCK_GROUP					\
 130	[MINSTREL_CCK_GROUP] = {			\
 131		.streams = 0,				\
 132		.flags = 0,				\
 133		.duration = {				\
 134			CCK_DURATION_LIST(false),	\
 135			CCK_DURATION_LIST(true)		\
 136		}					\
 137	}
 138
 139#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
 140static bool minstrel_vht_only = true;
 141module_param(minstrel_vht_only, bool, 0644);
 142MODULE_PARM_DESC(minstrel_vht_only,
 143		 "Use only VHT rates when VHT is supported by sta.");
 144#endif
 145
 146/*
 147 * To enable sufficiently targeted rate sampling, MCS rates are divided into
 148 * groups, based on the number of streams and flags (HT40, SGI) that they
 149 * use.
 150 *
 151 * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
 152 * BW -> SGI -> #streams
 153 */
 154const struct mcs_group minstrel_mcs_groups[] = {
 155	MCS_GROUP(1, 0, BW_20),
 156	MCS_GROUP(2, 0, BW_20),
 157#if MINSTREL_MAX_STREAMS >= 3
 158	MCS_GROUP(3, 0, BW_20),
 159#endif
 160
 161	MCS_GROUP(1, 1, BW_20),
 162	MCS_GROUP(2, 1, BW_20),
 163#if MINSTREL_MAX_STREAMS >= 3
 164	MCS_GROUP(3, 1, BW_20),
 165#endif
 166
 167	MCS_GROUP(1, 0, BW_40),
 168	MCS_GROUP(2, 0, BW_40),
 169#if MINSTREL_MAX_STREAMS >= 3
 170	MCS_GROUP(3, 0, BW_40),
 171#endif
 172
 173	MCS_GROUP(1, 1, BW_40),
 174	MCS_GROUP(2, 1, BW_40),
 175#if MINSTREL_MAX_STREAMS >= 3
 176	MCS_GROUP(3, 1, BW_40),
 177#endif
 178
 179	CCK_GROUP,
 180
 181#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
 182	VHT_GROUP(1, 0, BW_20),
 183	VHT_GROUP(2, 0, BW_20),
 184#if MINSTREL_MAX_STREAMS >= 3
 185	VHT_GROUP(3, 0, BW_20),
 186#endif
 187
 188	VHT_GROUP(1, 1, BW_20),
 189	VHT_GROUP(2, 1, BW_20),
 190#if MINSTREL_MAX_STREAMS >= 3
 191	VHT_GROUP(3, 1, BW_20),
 192#endif
 193
 194	VHT_GROUP(1, 0, BW_40),
 195	VHT_GROUP(2, 0, BW_40),
 196#if MINSTREL_MAX_STREAMS >= 3
 197	VHT_GROUP(3, 0, BW_40),
 198#endif
 199
 200	VHT_GROUP(1, 1, BW_40),
 201	VHT_GROUP(2, 1, BW_40),
 202#if MINSTREL_MAX_STREAMS >= 3
 203	VHT_GROUP(3, 1, BW_40),
 204#endif
 205
 206	VHT_GROUP(1, 0, BW_80),
 207	VHT_GROUP(2, 0, BW_80),
 208#if MINSTREL_MAX_STREAMS >= 3
 209	VHT_GROUP(3, 0, BW_80),
 210#endif
 211
 212	VHT_GROUP(1, 1, BW_80),
 213	VHT_GROUP(2, 1, BW_80),
 214#if MINSTREL_MAX_STREAMS >= 3
 215	VHT_GROUP(3, 1, BW_80),
 216#endif
 217#endif
 218};
 219
 220static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
 221
 222static void
 223minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
 224
 225/*
 226 * Some VHT MCSes are invalid (when Ndbps / Nes is not an integer)
 227 * e.g for MCS9@20MHzx1Nss: Ndbps=8x52*(5/6) Nes=1
 228 *
 229 * Returns the valid mcs map for struct minstrel_mcs_group_data.supported
 230 */
 231static u16
 232minstrel_get_valid_vht_rates(int bw, int nss, __le16 mcs_map)
 233{
 234	u16 mask = 0;
 235
 236	if (bw == BW_20) {
 237		if (nss != 3 && nss != 6)
 238			mask = BIT(9);
 239	} else if (bw == BW_80) {
 240		if (nss == 3 || nss == 7)
 241			mask = BIT(6);
 242		else if (nss == 6)
 243			mask = BIT(9);
 244	} else {
 245		WARN_ON(bw != BW_40);
 246	}
 247
 248	switch ((le16_to_cpu(mcs_map) >> (2 * (nss - 1))) & 3) {
 249	case IEEE80211_VHT_MCS_SUPPORT_0_7:
 250		mask |= 0x300;
 251		break;
 252	case IEEE80211_VHT_MCS_SUPPORT_0_8:
 253		mask |= 0x200;
 254		break;
 255	case IEEE80211_VHT_MCS_SUPPORT_0_9:
 256		break;
 257	default:
 258		mask = 0x3ff;
 259	}
 260
 261	return 0x3ff & ~mask;
 262}
 263
 264/*
 265 * Look up an MCS group index based on mac80211 rate information
 266 */
 267static int
 268minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
 269{
 270	return GROUP_IDX((rate->idx / 8) + 1,
 271			 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
 272			 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
 273}
 274
 275static int
 276minstrel_vht_get_group_idx(struct ieee80211_tx_rate *rate)
 277{
 278	return VHT_GROUP_IDX(ieee80211_rate_get_vht_nss(rate),
 279			     !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
 280			     !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH) +
 281			     2*!!(rate->flags & IEEE80211_TX_RC_80_MHZ_WIDTH));
 282}
 283
 284static struct minstrel_rate_stats *
 285minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
 286		      struct ieee80211_tx_rate *rate)
 287{
 288	int group, idx;
 289
 290	if (rate->flags & IEEE80211_TX_RC_MCS) {
 291		group = minstrel_ht_get_group_idx(rate);
 292		idx = rate->idx % 8;
 293	} else if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
 294		group = minstrel_vht_get_group_idx(rate);
 295		idx = ieee80211_rate_get_vht_mcs(rate);
 296	} else {
 297		group = MINSTREL_CCK_GROUP;
 298
 299		for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++)
 300			if (rate->idx == mp->cck_rates[idx])
 301				break;
 302
 303		/* short preamble */
 304		if (!(mi->groups[group].supported & BIT(idx)))
 305			idx += 4;
 306	}
 307	return &mi->groups[group].rates[idx];
 308}
 309
 310static inline struct minstrel_rate_stats *
 311minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
 312{
 313	return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
 314}
 315
 316/*
 317 * Return current throughput based on the average A-MPDU length, taking into
 318 * account the expected number of retransmissions and their expected length
 319 */
 320int
 321minstrel_ht_get_tp_avg(struct minstrel_ht_sta *mi, int group, int rate,
 322		       int prob_ewma)
 323{
 324	unsigned int nsecs = 0;
 325
 326	/* do not account throughput if sucess prob is below 10% */
 327	if (prob_ewma < MINSTREL_FRAC(10, 100))
 328		return 0;
 329
 330	if (group != MINSTREL_CCK_GROUP)
 331		nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
 332
 333	nsecs += minstrel_mcs_groups[group].duration[rate];
 334
 335	/*
 336	 * For the throughput calculation, limit the probability value to 90% to
 337	 * account for collision related packet error rate fluctuation
 338	 * (prob is scaled - see MINSTREL_FRAC above)
 339	 */
 340	if (prob_ewma > MINSTREL_FRAC(90, 100))
 341		return MINSTREL_TRUNC(100000 * ((MINSTREL_FRAC(90, 100) * 1000)
 342								      / nsecs));
 343	else
 344		return MINSTREL_TRUNC(100000 * ((prob_ewma * 1000) / nsecs));
 345}
 346
 347/*
 348 * Find & sort topmost throughput rates
 349 *
 350 * If multiple rates provide equal throughput the sorting is based on their
 351 * current success probability. Higher success probability is preferred among
 352 * MCS groups, CCK rates do not provide aggregation and are therefore at last.
 353 */
 354static void
 355minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u16 index,
 356			       u16 *tp_list)
 357{
 358	int cur_group, cur_idx, cur_tp_avg, cur_prob;
 359	int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
 360	int j = MAX_THR_RATES;
 361
 362	cur_group = index / MCS_GROUP_RATES;
 363	cur_idx = index  % MCS_GROUP_RATES;
 364	cur_prob = mi->groups[cur_group].rates[cur_idx].prob_ewma;
 365	cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx, cur_prob);
 366
 367	do {
 368		tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
 369		tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
 370		tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
 371		tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx,
 372						    tmp_prob);
 373		if (cur_tp_avg < tmp_tp_avg ||
 374		    (cur_tp_avg == tmp_tp_avg && cur_prob <= tmp_prob))
 375			break;
 376		j--;
 377	} while (j > 0);
 378
 379	if (j < MAX_THR_RATES - 1) {
 380		memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) *
 381		       (MAX_THR_RATES - (j + 1))));
 382	}
 383	if (j < MAX_THR_RATES)
 384		tp_list[j] = index;
 385}
 386
 387/*
 388 * Find and set the topmost probability rate per sta and per group
 389 */
 390static void
 391minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 index)
 392{
 393	struct minstrel_mcs_group_data *mg;
 394	struct minstrel_rate_stats *mrs;
 395	int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
 396	int max_tp_group, cur_tp_avg, cur_group, cur_idx;
 397	int max_gpr_group, max_gpr_idx;
 398	int max_gpr_tp_avg, max_gpr_prob;
 399
 400	cur_group = index / MCS_GROUP_RATES;
 401	cur_idx = index % MCS_GROUP_RATES;
 402	mg = &mi->groups[index / MCS_GROUP_RATES];
 403	mrs = &mg->rates[index % MCS_GROUP_RATES];
 404
 405	tmp_group = mi->max_prob_rate / MCS_GROUP_RATES;
 406	tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES;
 407	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
 408	tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
 409
 410	/* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
 411	 * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
 412	max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES;
 413	if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) &&
 414	    (max_tp_group != MINSTREL_CCK_GROUP))
 415		return;
 416
 417	max_gpr_group = mg->max_group_prob_rate / MCS_GROUP_RATES;
 418	max_gpr_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
 419	max_gpr_prob = mi->groups[max_gpr_group].rates[max_gpr_idx].prob_ewma;
 420
 421	if (mrs->prob_ewma > MINSTREL_FRAC(75, 100)) {
 422		cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx,
 423						    mrs->prob_ewma);
 424		if (cur_tp_avg > tmp_tp_avg)
 425			mi->max_prob_rate = index;
 426
 427		max_gpr_tp_avg = minstrel_ht_get_tp_avg(mi, max_gpr_group,
 428							max_gpr_idx,
 429							max_gpr_prob);
 430		if (cur_tp_avg > max_gpr_tp_avg)
 431			mg->max_group_prob_rate = index;
 432	} else {
 433		if (mrs->prob_ewma > tmp_prob)
 434			mi->max_prob_rate = index;
 435		if (mrs->prob_ewma > max_gpr_prob)
 436			mg->max_group_prob_rate = index;
 437	}
 438}
 439
 440
 441/*
 442 * Assign new rate set per sta and use CCK rates only if the fastest
 443 * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted
 444 * rate sets where MCS and CCK rates are mixed, because CCK rates can
 445 * not use aggregation.
 446 */
 447static void
 448minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi,
 449				 u16 tmp_mcs_tp_rate[MAX_THR_RATES],
 450				 u16 tmp_cck_tp_rate[MAX_THR_RATES])
 451{
 452	unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp, tmp_prob;
 453	int i;
 454
 455	tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES;
 456	tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES;
 457	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
 458	tmp_cck_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
 459
 460	tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES;
 461	tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES;
 462	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
 463	tmp_mcs_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
 464
 465	if (tmp_cck_tp > tmp_mcs_tp) {
 466		for(i = 0; i < MAX_THR_RATES; i++) {
 467			minstrel_ht_sort_best_tp_rates(mi, tmp_cck_tp_rate[i],
 468						       tmp_mcs_tp_rate);
 469		}
 470	}
 471
 472}
 473
 474/*
 475 * Try to increase robustness of max_prob rate by decrease number of
 476 * streams if possible.
 477 */
 478static inline void
 479minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
 480{
 481	struct minstrel_mcs_group_data *mg;
 482	int tmp_max_streams, group, tmp_idx, tmp_prob;
 483	int tmp_tp = 0;
 484
 485	tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
 486			  MCS_GROUP_RATES].streams;
 487	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
 488		mg = &mi->groups[group];
 489		if (!mg->supported || group == MINSTREL_CCK_GROUP)
 490			continue;
 491
 492		tmp_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
 493		tmp_prob = mi->groups[group].rates[tmp_idx].prob_ewma;
 494
 495		if (tmp_tp < minstrel_ht_get_tp_avg(mi, group, tmp_idx, tmp_prob) &&
 496		   (minstrel_mcs_groups[group].streams < tmp_max_streams)) {
 497				mi->max_prob_rate = mg->max_group_prob_rate;
 498				tmp_tp = minstrel_ht_get_tp_avg(mi, group,
 499								tmp_idx,
 500								tmp_prob);
 501		}
 502	}
 503}
 504
 505/*
 506 * Update rate statistics and select new primary rates
 507 *
 508 * Rules for rate selection:
 509 *  - max_prob_rate must use only one stream, as a tradeoff between delivery
 510 *    probability and throughput during strong fluctuations
 511 *  - as long as the max prob rate has a probability of more than 75%, pick
 512 *    higher throughput rates, even if the probablity is a bit lower
 513 */
 514static void
 515minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 516{
 517	struct minstrel_mcs_group_data *mg;
 518	struct minstrel_rate_stats *mrs;
 519	int group, i, j, cur_prob;
 520	u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
 521	u16 tmp_cck_tp_rate[MAX_THR_RATES], index;
 522
 523	if (mi->ampdu_packets > 0) {
 524		mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
 525			MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
 526		mi->ampdu_len = 0;
 527		mi->ampdu_packets = 0;
 528	}
 529
 530	mi->sample_slow = 0;
 531	mi->sample_count = 0;
 532
 533	/* Initialize global rate indexes */
 534	for(j = 0; j < MAX_THR_RATES; j++){
 535		tmp_mcs_tp_rate[j] = 0;
 536		tmp_cck_tp_rate[j] = 0;
 537	}
 538
 539	/* Find best rate sets within all MCS groups*/
 540	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
 541
 542		mg = &mi->groups[group];
 543		if (!mg->supported)
 544			continue;
 545
 546		mi->sample_count++;
 547
 548		/* (re)Initialize group rate indexes */
 549		for(j = 0; j < MAX_THR_RATES; j++)
 550			tmp_group_tp_rate[j] = group;
 551
 552		for (i = 0; i < MCS_GROUP_RATES; i++) {
 553			if (!(mg->supported & BIT(i)))
 554				continue;
 555
 556			index = MCS_GROUP_RATES * group + i;
 557
 558			mrs = &mg->rates[i];
 559			mrs->retry_updated = false;
 560			minstrel_calc_rate_stats(mrs);
 561			cur_prob = mrs->prob_ewma;
 562
 563			if (minstrel_ht_get_tp_avg(mi, group, i, cur_prob) == 0)
 564				continue;
 565
 566			/* Find max throughput rate set */
 567			if (group != MINSTREL_CCK_GROUP) {
 568				minstrel_ht_sort_best_tp_rates(mi, index,
 569							       tmp_mcs_tp_rate);
 570			} else if (group == MINSTREL_CCK_GROUP) {
 571				minstrel_ht_sort_best_tp_rates(mi, index,
 572							       tmp_cck_tp_rate);
 573			}
 574
 575			/* Find max throughput rate set within a group */
 576			minstrel_ht_sort_best_tp_rates(mi, index,
 577						       tmp_group_tp_rate);
 578
 579			/* Find max probability rate per group and global */
 580			minstrel_ht_set_best_prob_rate(mi, index);
 581		}
 582
 583		memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
 584		       sizeof(mg->max_group_tp_rate));
 585	}
 586
 587	/* Assign new rate set per sta */
 588	minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate);
 589	memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));
 590
 591	/* Try to increase robustness of max_prob_rate*/
 592	minstrel_ht_prob_rate_reduce_streams(mi);
 593
 594	/* try to sample all available rates during each interval */
 595	mi->sample_count *= 8;
 596
 597#ifdef CONFIG_MAC80211_DEBUGFS
 598	/* use fixed index if set */
 599	if (mp->fixed_rate_idx != -1) {
 600		for (i = 0; i < 4; i++)
 601			mi->max_tp_rate[i] = mp->fixed_rate_idx;
 602		mi->max_prob_rate = mp->fixed_rate_idx;
 603	}
 604#endif
 605
 606	/* Reset update timer */
 607	mi->last_stats_update = jiffies;
 608}
 609
 610static bool
 611minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)
 612{
 613	if (rate->idx < 0)
 614		return false;
 615
 616	if (!rate->count)
 617		return false;
 618
 619	if (rate->flags & IEEE80211_TX_RC_MCS ||
 620	    rate->flags & IEEE80211_TX_RC_VHT_MCS)
 621		return true;
 622
 623	return rate->idx == mp->cck_rates[0] ||
 624	       rate->idx == mp->cck_rates[1] ||
 625	       rate->idx == mp->cck_rates[2] ||
 626	       rate->idx == mp->cck_rates[3];
 627}
 628
 629static void
 630minstrel_set_next_sample_idx(struct minstrel_ht_sta *mi)
 631{
 632	struct minstrel_mcs_group_data *mg;
 633
 634	for (;;) {
 635		mi->sample_group++;
 636		mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
 637		mg = &mi->groups[mi->sample_group];
 638
 639		if (!mg->supported)
 640			continue;
 641
 642		if (++mg->index >= MCS_GROUP_RATES) {
 643			mg->index = 0;
 644			if (++mg->column >= ARRAY_SIZE(sample_table))
 645				mg->column = 0;
 646		}
 647		break;
 648	}
 649}
 650
 651static void
 652minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u16 *idx, bool primary)
 653{
 654	int group, orig_group;
 655
 656	orig_group = group = *idx / MCS_GROUP_RATES;
 657	while (group > 0) {
 658		group--;
 659
 660		if (!mi->groups[group].supported)
 661			continue;
 662
 663		if (minstrel_mcs_groups[group].streams >
 664		    minstrel_mcs_groups[orig_group].streams)
 665			continue;
 666
 667		if (primary)
 668			*idx = mi->groups[group].max_group_tp_rate[0];
 669		else
 670			*idx = mi->groups[group].max_group_tp_rate[1];
 671		break;
 672	}
 673}
 674
 675static void
 676minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
 677{
 678	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 679	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 680	u16 tid;
 681
 682	if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
 683		return;
 684
 685	if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
 686		return;
 687
 688	if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
 689		return;
 690
 691	tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
 692	if (likely(sta->ampdu_mlme.tid_tx[tid]))
 693		return;
 694
 695	ieee80211_start_tx_ba_session(pubsta, tid, 0);
 696}
 697
 698static void
 699minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
 700                      struct ieee80211_sta *sta, void *priv_sta,
 701                      struct ieee80211_tx_info *info)
 702{
 703	struct minstrel_ht_sta_priv *msp = priv_sta;
 704	struct minstrel_ht_sta *mi = &msp->ht;
 705	struct ieee80211_tx_rate *ar = info->status.rates;
 706	struct minstrel_rate_stats *rate, *rate2;
 707	struct minstrel_priv *mp = priv;
 708	bool last, update = false;
 709	int i;
 710
 711	if (!msp->is_ht)
 712		return mac80211_minstrel.tx_status_noskb(priv, sband, sta,
 713							 &msp->legacy, info);
 714
 715	/* This packet was aggregated but doesn't carry status info */
 716	if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
 717	    !(info->flags & IEEE80211_TX_STAT_AMPDU))
 718		return;
 719
 720	if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
 721		info->status.ampdu_ack_len =
 722			(info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
 723		info->status.ampdu_len = 1;
 724	}
 725
 726	mi->ampdu_packets++;
 727	mi->ampdu_len += info->status.ampdu_len;
 728
 729	if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
 730		mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
 731		mi->sample_tries = 1;
 732		mi->sample_count--;
 733	}
 734
 735	if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
 736		mi->sample_packets += info->status.ampdu_len;
 737
 738	last = !minstrel_ht_txstat_valid(mp, &ar[0]);
 739	for (i = 0; !last; i++) {
 740		last = (i == IEEE80211_TX_MAX_RATES - 1) ||
 741		       !minstrel_ht_txstat_valid(mp, &ar[i + 1]);
 742
 743		rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
 744
 745		if (last)
 746			rate->success += info->status.ampdu_ack_len;
 747
 748		rate->attempts += ar[i].count * info->status.ampdu_len;
 749	}
 750
 751	/*
 752	 * check for sudden death of spatial multiplexing,
 753	 * downgrade to a lower number of streams if necessary.
 754	 */
 755	rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
 756	if (rate->attempts > 30 &&
 757	    MINSTREL_FRAC(rate->success, rate->attempts) <
 758	    MINSTREL_FRAC(20, 100)) {
 759		minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
 760		update = true;
 761	}
 762
 763	rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
 764	if (rate2->attempts > 30 &&
 765	    MINSTREL_FRAC(rate2->success, rate2->attempts) <
 766	    MINSTREL_FRAC(20, 100)) {
 767		minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
 768		update = true;
 769	}
 770
 771	if (time_after(jiffies, mi->last_stats_update +
 772				(mp->update_interval / 2 * HZ) / 1000)) {
 773		update = true;
 774		minstrel_ht_update_stats(mp, mi);
 775	}
 776
 777	if (update)
 778		minstrel_ht_update_rates(mp, mi);
 779}
 780
 781static void
 782minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
 783                         int index)
 784{
 785	struct minstrel_rate_stats *mrs;
 786	const struct mcs_group *group;
 787	unsigned int tx_time, tx_time_rtscts, tx_time_data;
 788	unsigned int cw = mp->cw_min;
 789	unsigned int ctime = 0;
 790	unsigned int t_slot = 9; /* FIXME */
 791	unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
 792	unsigned int overhead = 0, overhead_rtscts = 0;
 793
 794	mrs = minstrel_get_ratestats(mi, index);
 795	if (mrs->prob_ewma < MINSTREL_FRAC(1, 10)) {
 796		mrs->retry_count = 1;
 797		mrs->retry_count_rtscts = 1;
 798		return;
 799	}
 800
 801	mrs->retry_count = 2;
 802	mrs->retry_count_rtscts = 2;
 803	mrs->retry_updated = true;
 804
 805	group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
 806	tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
 807
 808	/* Contention time for first 2 tries */
 809	ctime = (t_slot * cw) >> 1;
 810	cw = min((cw << 1) | 1, mp->cw_max);
 811	ctime += (t_slot * cw) >> 1;
 812	cw = min((cw << 1) | 1, mp->cw_max);
 813
 814	if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
 815		overhead = mi->overhead;
 816		overhead_rtscts = mi->overhead_rtscts;
 817	}
 818
 819	/* Total TX time for data and Contention after first 2 tries */
 820	tx_time = ctime + 2 * (overhead + tx_time_data);
 821	tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
 822
 823	/* See how many more tries we can fit inside segment size */
 824	do {
 825		/* Contention time for this try */
 826		ctime = (t_slot * cw) >> 1;
 827		cw = min((cw << 1) | 1, mp->cw_max);
 828
 829		/* Total TX time after this try */
 830		tx_time += ctime + overhead + tx_time_data;
 831		tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
 832
 833		if (tx_time_rtscts < mp->segment_size)
 834			mrs->retry_count_rtscts++;
 835	} while ((tx_time < mp->segment_size) &&
 836	         (++mrs->retry_count < mp->max_retry));
 837}
 838
 839
 840static void
 841minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
 842                     struct ieee80211_sta_rates *ratetbl, int offset, int index)
 843{
 844	const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
 845	struct minstrel_rate_stats *mrs;
 846	u8 idx;
 847	u16 flags = group->flags;
 848
 849	mrs = minstrel_get_ratestats(mi, index);
 850	if (!mrs->retry_updated)
 851		minstrel_calc_retransmit(mp, mi, index);
 852
 853	if (mrs->prob_ewma < MINSTREL_FRAC(20, 100) || !mrs->retry_count) {
 854		ratetbl->rate[offset].count = 2;
 855		ratetbl->rate[offset].count_rts = 2;
 856		ratetbl->rate[offset].count_cts = 2;
 857	} else {
 858		ratetbl->rate[offset].count = mrs->retry_count;
 859		ratetbl->rate[offset].count_cts = mrs->retry_count;
 860		ratetbl->rate[offset].count_rts = mrs->retry_count_rtscts;
 861	}
 862
 863	if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP)
 864		idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
 865	else if (flags & IEEE80211_TX_RC_VHT_MCS)
 866		idx = ((group->streams - 1) << 4) |
 867		      ((index % MCS_GROUP_RATES) & 0xF);
 868	else
 869		idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;
 870
 871	/* enable RTS/CTS if needed:
 872	 *  - if station is in dynamic SMPS (and streams > 1)
 873	 *  - for fallback rates, to increase chances of getting through
 874	 */
 875	if (offset > 0 ||
 876	    (mi->sta->smps_mode == IEEE80211_SMPS_DYNAMIC &&
 877	     group->streams > 1)) {
 878		ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
 879		flags |= IEEE80211_TX_RC_USE_RTS_CTS;
 880	}
 881
 882	ratetbl->rate[offset].idx = idx;
 883	ratetbl->rate[offset].flags = flags;
 884}
 885
 886static inline int
 887minstrel_ht_get_prob_ewma(struct minstrel_ht_sta *mi, int rate)
 888{
 889	int group = rate / MCS_GROUP_RATES;
 890	rate %= MCS_GROUP_RATES;
 891	return mi->groups[group].rates[rate].prob_ewma;
 892}
 893
 894static int
 895minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta *mi)
 896{
 897	int group = mi->max_prob_rate / MCS_GROUP_RATES;
 898	const struct mcs_group *g = &minstrel_mcs_groups[group];
 899	int rate = mi->max_prob_rate % MCS_GROUP_RATES;
 900
 901	/* Disable A-MSDU if max_prob_rate is bad */
 902	if (mi->groups[group].rates[rate].prob_ewma < MINSTREL_FRAC(50, 100))
 903		return 1;
 904
 905	/* If the rate is slower than single-stream MCS1, make A-MSDU limit small */
 906	if (g->duration[rate] > MCS_DURATION(1, 0, 52))
 907		return 500;
 908
 909	/*
 910	 * If the rate is slower than single-stream MCS4, limit A-MSDU to usual
 911	 * data packet size
 912	 */
 913	if (g->duration[rate] > MCS_DURATION(1, 0, 104))
 914		return 1600;
 915
 916	/*
 917	 * If the rate is slower than single-stream MCS7, or if the max throughput
 918	 * rate success probability is less than 75%, limit A-MSDU to twice the usual
 919	 * data packet size
 920	 */
 921	if (g->duration[rate] > MCS_DURATION(1, 0, 260) ||
 922	    (minstrel_ht_get_prob_ewma(mi, mi->max_tp_rate[0]) <
 923	     MINSTREL_FRAC(75, 100)))
 924		return 3200;
 925
 926	/*
 927	 * HT A-MPDU limits maximum MPDU size under BA agreement to 4095 bytes.
 928	 * Since aggregation sessions are started/stopped without txq flush, use
 929	 * the limit here to avoid the complexity of having to de-aggregate
 930	 * packets in the queue.
 931	 */
 932	if (!mi->sta->vht_cap.vht_supported)
 933		return IEEE80211_MAX_MPDU_LEN_HT_BA;
 934
 935	/* unlimited */
 936	return 0;
 937}
 938
 939static void
 940minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 941{
 942	struct ieee80211_sta_rates *rates;
 943	int i = 0;
 944
 945	rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
 946	if (!rates)
 947		return;
 948
 949	/* Start with max_tp_rate[0] */
 950	minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
 951
 952	if (mp->hw->max_rates >= 3) {
 953		/* At least 3 tx rates supported, use max_tp_rate[1] next */
 954		minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]);
 955	}
 956
 957	if (mp->hw->max_rates >= 2) {
 958		/*
 959		 * At least 2 tx rates supported, use max_prob_rate next */
 960		minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
 961	}
 962
 963	mi->sta->max_rc_amsdu_len = minstrel_ht_get_max_amsdu_len(mi);
 964	rates->rate[i].idx = -1;
 965	rate_control_set_rates(mp->hw, mi->sta, rates);
 966}
 967
 968static inline int
 969minstrel_get_duration(int index)
 970{
 971	const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
 972	return group->duration[index % MCS_GROUP_RATES];
 973}
 974
 975static int
 976minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 977{
 978	struct minstrel_rate_stats *mrs;
 979	struct minstrel_mcs_group_data *mg;
 980	unsigned int sample_dur, sample_group, cur_max_tp_streams;
 981	int tp_rate1, tp_rate2;
 982	int sample_idx = 0;
 983
 984	if (mi->sample_wait > 0) {
 985		mi->sample_wait--;
 986		return -1;
 987	}
 988
 989	if (!mi->sample_tries)
 990		return -1;
 991
 992	sample_group = mi->sample_group;
 993	mg = &mi->groups[sample_group];
 994	sample_idx = sample_table[mg->column][mg->index];
 995	minstrel_set_next_sample_idx(mi);
 996
 997	if (!(mg->supported & BIT(sample_idx)))
 998		return -1;
 999
1000	mrs = &mg->rates[sample_idx];
1001	sample_idx += sample_group * MCS_GROUP_RATES;
1002
1003	/* Set tp_rate1, tp_rate2 to the highest / second highest max_tp_rate */
1004	if (minstrel_get_duration(mi->max_tp_rate[0]) >
1005	    minstrel_get_duration(mi->max_tp_rate[1])) {
1006		tp_rate1 = mi->max_tp_rate[1];
1007		tp_rate2 = mi->max_tp_rate[0];
1008	} else {
1009		tp_rate1 = mi->max_tp_rate[0];
1010		tp_rate2 = mi->max_tp_rate[1];
1011	}
1012
1013	/*
1014	 * Sampling might add some overhead (RTS, no aggregation)
1015	 * to the frame. Hence, don't use sampling for the highest currently
1016	 * used highest throughput or probability rate.
1017	 */
1018	if (sample_idx == mi->max_tp_rate[0] || sample_idx == mi->max_prob_rate)
 
 
1019		return -1;
1020
1021	/*
1022	 * Do not sample if the probability is already higher than 95%
1023	 * to avoid wasting airtime.
1024	 */
1025	if (mrs->prob_ewma > MINSTREL_FRAC(95, 100))
1026		return -1;
1027
1028	/*
1029	 * Make sure that lower rates get sampled only occasionally,
1030	 * if the link is working perfectly.
1031	 */
1032
1033	cur_max_tp_streams = minstrel_mcs_groups[tp_rate1 /
1034		MCS_GROUP_RATES].streams;
1035	sample_dur = minstrel_get_duration(sample_idx);
1036	if (sample_dur >= minstrel_get_duration(tp_rate2) &&
1037	    (cur_max_tp_streams - 1 <
1038	     minstrel_mcs_groups[sample_group].streams ||
1039	     sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
1040		if (mrs->sample_skipped < 20)
1041			return -1;
1042
1043		if (mi->sample_slow++ > 2)
1044			return -1;
1045	}
1046	mi->sample_tries--;
1047
1048	return sample_idx;
1049}
1050
1051static void
1052minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp,
1053				    struct minstrel_ht_sta *mi, bool val)
1054{
1055	u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported;
1056
1057	if (!supported || !mi->cck_supported_short)
1058		return;
1059
1060	if (supported & (mi->cck_supported_short << (val * 4)))
1061		return;
1062
1063	supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4);
1064	mi->groups[MINSTREL_CCK_GROUP].supported = supported;
1065}
1066
1067static void
1068minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
1069                     struct ieee80211_tx_rate_control *txrc)
1070{
1071	const struct mcs_group *sample_group;
1072	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
1073	struct ieee80211_tx_rate *rate = &info->status.rates[0];
1074	struct minstrel_ht_sta_priv *msp = priv_sta;
1075	struct minstrel_ht_sta *mi = &msp->ht;
1076	struct minstrel_priv *mp = priv;
1077	int sample_idx;
1078
1079	if (rate_control_send_low(sta, priv_sta, txrc))
1080		return;
1081
1082	if (!msp->is_ht)
1083		return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
1084
1085	if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
1086	    mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)
1087		minstrel_aggr_check(sta, txrc->skb);
1088
1089	info->flags |= mi->tx_flags;
1090	minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble);
1091
1092#ifdef CONFIG_MAC80211_DEBUGFS
1093	if (mp->fixed_rate_idx != -1)
1094		return;
1095#endif
1096
1097	/* Don't use EAPOL frames for sampling on non-mrr hw */
1098	if (mp->hw->max_rates == 1 &&
1099	    (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
1100		sample_idx = -1;
1101	else
1102		sample_idx = minstrel_get_sample_rate(mp, mi);
1103
1104	mi->total_packets++;
1105
1106	/* wraparound */
1107	if (mi->total_packets == ~0) {
1108		mi->total_packets = 0;
1109		mi->sample_packets = 0;
1110	}
1111
1112	if (sample_idx < 0)
1113		return;
1114
1115	sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
1116	info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
1117	rate->count = 1;
1118
1119	if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
1120		int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
1121		rate->idx = mp->cck_rates[idx];
1122	} else if (sample_group->flags & IEEE80211_TX_RC_VHT_MCS) {
1123		ieee80211_rate_set_vht(rate, sample_idx % MCS_GROUP_RATES,
1124				       sample_group->streams);
1125	} else {
1126		rate->idx = sample_idx % MCS_GROUP_RATES +
1127			    (sample_group->streams - 1) * 8;
1128	}
1129
1130	rate->flags = sample_group->flags;
1131}
1132
1133static void
1134minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
1135		       struct ieee80211_supported_band *sband,
1136		       struct ieee80211_sta *sta)
1137{
1138	int i;
1139
1140	if (sband->band != NL80211_BAND_2GHZ)
1141		return;
1142
1143	if (!ieee80211_hw_check(mp->hw, SUPPORTS_HT_CCK_RATES))
1144		return;
1145
1146	mi->cck_supported = 0;
1147	mi->cck_supported_short = 0;
1148	for (i = 0; i < 4; i++) {
1149		if (!rate_supported(sta, sband->band, mp->cck_rates[i]))
1150			continue;
1151
1152		mi->cck_supported |= BIT(i);
1153		if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)
1154			mi->cck_supported_short |= BIT(i);
1155	}
1156
1157	mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported;
1158}
1159
1160static void
1161minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
1162			struct cfg80211_chan_def *chandef,
1163                        struct ieee80211_sta *sta, void *priv_sta)
1164{
1165	struct minstrel_priv *mp = priv;
1166	struct minstrel_ht_sta_priv *msp = priv_sta;
1167	struct minstrel_ht_sta *mi = &msp->ht;
1168	struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
1169	u16 sta_cap = sta->ht_cap.cap;
1170	struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap;
1171	int use_vht;
1172	int n_supported = 0;
1173	int ack_dur;
1174	int stbc;
1175	int i;
1176
1177	/* fall back to the old minstrel for legacy stations */
1178	if (!sta->ht_cap.ht_supported)
1179		goto use_legacy;
1180
1181	BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != MINSTREL_GROUPS_NB);
1182
1183#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
1184	if (vht_cap->vht_supported)
1185		use_vht = vht_cap->vht_mcs.tx_mcs_map != cpu_to_le16(~0);
1186	else
1187#endif
1188	use_vht = 0;
1189
1190	msp->is_ht = true;
1191	memset(mi, 0, sizeof(*mi));
1192
1193	mi->sta = sta;
1194	mi->last_stats_update = jiffies;
1195
1196	ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
1197	mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
1198	mi->overhead += ack_dur;
1199	mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
1200
1201	mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
1202
1203	/* When using MRR, sample more on the first attempt, without delay */
1204	if (mp->has_mrr) {
1205		mi->sample_count = 16;
1206		mi->sample_wait = 0;
1207	} else {
1208		mi->sample_count = 8;
1209		mi->sample_wait = 8;
1210	}
1211	mi->sample_tries = 4;
1212
1213	/* TODO tx_flags for vht - ATM the RC API is not fine-grained enough */
1214	if (!use_vht) {
1215		stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
1216			IEEE80211_HT_CAP_RX_STBC_SHIFT;
1217		mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
1218
1219		if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
1220			mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
1221	}
1222
1223	for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
1224		u32 gflags = minstrel_mcs_groups[i].flags;
1225		int bw, nss;
1226
1227		mi->groups[i].supported = 0;
1228		if (i == MINSTREL_CCK_GROUP) {
1229			minstrel_ht_update_cck(mp, mi, sband, sta);
1230			continue;
1231		}
1232
1233		if (gflags & IEEE80211_TX_RC_SHORT_GI) {
1234			if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH) {
1235				if (!(sta_cap & IEEE80211_HT_CAP_SGI_40))
1236					continue;
1237			} else {
1238				if (!(sta_cap & IEEE80211_HT_CAP_SGI_20))
1239					continue;
1240			}
1241		}
1242
1243		if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH &&
1244		    sta->bandwidth < IEEE80211_STA_RX_BW_40)
1245			continue;
1246
1247		nss = minstrel_mcs_groups[i].streams;
1248
1249		/* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
1250		if (sta->smps_mode == IEEE80211_SMPS_STATIC && nss > 1)
1251			continue;
1252
1253		/* HT rate */
1254		if (gflags & IEEE80211_TX_RC_MCS) {
1255#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
1256			if (use_vht && minstrel_vht_only)
1257				continue;
1258#endif
1259			mi->groups[i].supported = mcs->rx_mask[nss - 1];
1260			if (mi->groups[i].supported)
1261				n_supported++;
1262			continue;
1263		}
1264
1265		/* VHT rate */
1266		if (!vht_cap->vht_supported ||
1267		    WARN_ON(!(gflags & IEEE80211_TX_RC_VHT_MCS)) ||
1268		    WARN_ON(gflags & IEEE80211_TX_RC_160_MHZ_WIDTH))
1269			continue;
1270
1271		if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH) {
1272			if (sta->bandwidth < IEEE80211_STA_RX_BW_80 ||
1273			    ((gflags & IEEE80211_TX_RC_SHORT_GI) &&
1274			     !(vht_cap->cap & IEEE80211_VHT_CAP_SHORT_GI_80))) {
1275				continue;
1276			}
1277		}
1278
1279		if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH)
1280			bw = BW_40;
1281		else if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH)
1282			bw = BW_80;
1283		else
1284			bw = BW_20;
1285
1286		mi->groups[i].supported = minstrel_get_valid_vht_rates(bw, nss,
1287				vht_cap->vht_mcs.tx_mcs_map);
1288
1289		if (mi->groups[i].supported)
1290			n_supported++;
1291	}
1292
1293	if (!n_supported)
1294		goto use_legacy;
1295
1296	/* create an initial rate table with the lowest supported rates */
1297	minstrel_ht_update_stats(mp, mi);
1298	minstrel_ht_update_rates(mp, mi);
1299
1300	return;
1301
1302use_legacy:
1303	msp->is_ht = false;
1304	memset(&msp->legacy, 0, sizeof(msp->legacy));
1305	msp->legacy.r = msp->ratelist;
1306	msp->legacy.sample_table = msp->sample_table;
1307	return mac80211_minstrel.rate_init(priv, sband, chandef, sta,
1308					   &msp->legacy);
1309}
1310
1311static void
1312minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
1313		      struct cfg80211_chan_def *chandef,
1314                      struct ieee80211_sta *sta, void *priv_sta)
1315{
1316	minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1317}
1318
1319static void
1320minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
1321			struct cfg80211_chan_def *chandef,
1322                        struct ieee80211_sta *sta, void *priv_sta,
1323                        u32 changed)
1324{
1325	minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta);
1326}
1327
1328static void *
1329minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
1330{
1331	struct ieee80211_supported_band *sband;
1332	struct minstrel_ht_sta_priv *msp;
1333	struct minstrel_priv *mp = priv;
1334	struct ieee80211_hw *hw = mp->hw;
1335	int max_rates = 0;
1336	int i;
1337
1338	for (i = 0; i < NUM_NL80211_BANDS; i++) {
1339		sband = hw->wiphy->bands[i];
1340		if (sband && sband->n_bitrates > max_rates)
1341			max_rates = sband->n_bitrates;
1342	}
1343
1344	msp = kzalloc(sizeof(*msp), gfp);
1345	if (!msp)
1346		return NULL;
1347
1348	msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
1349	if (!msp->ratelist)
1350		goto error;
1351
1352	msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
1353	if (!msp->sample_table)
1354		goto error1;
1355
1356	return msp;
1357
1358error1:
1359	kfree(msp->ratelist);
1360error:
1361	kfree(msp);
1362	return NULL;
1363}
1364
1365static void
1366minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
1367{
1368	struct minstrel_ht_sta_priv *msp = priv_sta;
1369
1370	kfree(msp->sample_table);
1371	kfree(msp->ratelist);
1372	kfree(msp);
1373}
1374
1375static void *
1376minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
1377{
1378	return mac80211_minstrel.alloc(hw, debugfsdir);
1379}
1380
1381static void
1382minstrel_ht_free(void *priv)
1383{
1384	mac80211_minstrel.free(priv);
1385}
1386
1387static u32 minstrel_ht_get_expected_throughput(void *priv_sta)
1388{
1389	struct minstrel_ht_sta_priv *msp = priv_sta;
1390	struct minstrel_ht_sta *mi = &msp->ht;
1391	int i, j, prob, tp_avg;
1392
1393	if (!msp->is_ht)
1394		return mac80211_minstrel.get_expected_throughput(priv_sta);
1395
1396	i = mi->max_tp_rate[0] / MCS_GROUP_RATES;
1397	j = mi->max_tp_rate[0] % MCS_GROUP_RATES;
1398	prob = mi->groups[i].rates[j].prob_ewma;
1399
1400	/* convert tp_avg from pkt per second in kbps */
1401	tp_avg = minstrel_ht_get_tp_avg(mi, i, j, prob) * 10;
1402	tp_avg = tp_avg * AVG_PKT_SIZE * 8 / 1024;
1403
1404	return tp_avg;
1405}
1406
1407static const struct rate_control_ops mac80211_minstrel_ht = {
1408	.name = "minstrel_ht",
1409	.tx_status_noskb = minstrel_ht_tx_status,
1410	.get_rate = minstrel_ht_get_rate,
1411	.rate_init = minstrel_ht_rate_init,
1412	.rate_update = minstrel_ht_rate_update,
1413	.alloc_sta = minstrel_ht_alloc_sta,
1414	.free_sta = minstrel_ht_free_sta,
1415	.alloc = minstrel_ht_alloc,
1416	.free = minstrel_ht_free,
1417#ifdef CONFIG_MAC80211_DEBUGFS
1418	.add_sta_debugfs = minstrel_ht_add_sta_debugfs,
1419	.remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
1420#endif
1421	.get_expected_throughput = minstrel_ht_get_expected_throughput,
1422};
1423
1424
1425static void __init init_sample_table(void)
1426{
1427	int col, i, new_idx;
1428	u8 rnd[MCS_GROUP_RATES];
1429
1430	memset(sample_table, 0xff, sizeof(sample_table));
1431	for (col = 0; col < SAMPLE_COLUMNS; col++) {
1432		prandom_bytes(rnd, sizeof(rnd));
1433		for (i = 0; i < MCS_GROUP_RATES; i++) {
1434			new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
1435			while (sample_table[col][new_idx] != 0xff)
1436				new_idx = (new_idx + 1) % MCS_GROUP_RATES;
1437
1438			sample_table[col][new_idx] = i;
1439		}
1440	}
1441}
1442
1443int __init
1444rc80211_minstrel_ht_init(void)
1445{
1446	init_sample_table();
1447	return ieee80211_rate_control_register(&mac80211_minstrel_ht);
1448}
1449
1450void
1451rc80211_minstrel_ht_exit(void)
1452{
1453	ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
1454}