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rc80211_minstrel_ht.c
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rc80211_minstrel_ht.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2010-2013 Felix Fietkau <[email protected]>
* Copyright (C) 2019-2021 Intel Corporation
*/
#include <linux/netdevice.h>
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/debugfs.h>
#include <linux/random.h>
#include <linux/moduleparam.h>
#include <linux/ieee80211.h>
#include <net/mac80211.h>
#include "rate.h"
#include "sta_info.h"
#include "rc80211_minstrel_ht.h"
#define AVG_AMPDU_SIZE 16
#define AVG_PKT_SIZE 1200
/* Number of bits for an average sized packet */
#define MCS_NBITS ((AVG_PKT_SIZE * AVG_AMPDU_SIZE) << 3)
/* Number of symbols for a packet with (bps) bits per symbol */
#define MCS_NSYMS(bps) DIV_ROUND_UP(MCS_NBITS, (bps))
/* Transmission time (nanoseconds) for a packet containing (syms) symbols */
#define MCS_SYMBOL_TIME(sgi, syms) \
(sgi ? \
((syms) * 18000 + 4000) / 5 : /* syms * 3.6 us */ \
((syms) * 1000) << 2 /* syms * 4 us */ \
)
/* 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))) / AVG_AMPDU_SIZE)
#define BW_20 0
#define BW_40 1
#define BW_80 2
/*
* Define group sort order: HT40 -> SGI -> #streams
*/
#define GROUP_IDX(_streams, _sgi, _ht40) \
MINSTREL_HT_GROUP_0 + \
MINSTREL_MAX_STREAMS * 2 * _ht40 + \
MINSTREL_MAX_STREAMS * _sgi + \
_streams - 1
#define _MAX(a, b) (((a)>(b))?(a):(b))
#define GROUP_SHIFT(duration) \
_MAX(0, 16 - __builtin_clz(duration))
/* MCS rate information for an MCS group */
#define __MCS_GROUP(_streams, _sgi, _ht40, _s) \
[GROUP_IDX(_streams, _sgi, _ht40)] = { \
.streams = _streams, \
.shift = _s, \
.bw = _ht40, \
.flags = \
IEEE80211_TX_RC_MCS | \
(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
(_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
.duration = { \
MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26) >> _s, \
MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52) >> _s, \
MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78) >> _s, \
MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104) >> _s, \
MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156) >> _s, \
MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208) >> _s, \
MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234) >> _s, \
MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) >> _s \
} \
}
#define MCS_GROUP_SHIFT(_streams, _sgi, _ht40) \
GROUP_SHIFT(MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26))
#define MCS_GROUP(_streams, _sgi, _ht40) \
__MCS_GROUP(_streams, _sgi, _ht40, \
MCS_GROUP_SHIFT(_streams, _sgi, _ht40))
#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, _s) \
[VHT_GROUP_IDX(_streams, _sgi, _bw)] = { \
.streams = _streams, \
.shift = _s, \
.bw = _bw, \
.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)) >> _s, \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 234, 108, 52)) >> _s, \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 351, 162, 78)) >> _s, \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 468, 216, 104)) >> _s, \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 702, 324, 156)) >> _s, \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 936, 432, 208)) >> _s, \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 1053, 486, 234)) >> _s, \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 1170, 540, 260)) >> _s, \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 1404, 648, 312)) >> _s, \
MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 1560, 720, 346)) >> _s \
} \
}
#define VHT_GROUP_SHIFT(_streams, _sgi, _bw) \
GROUP_SHIFT(MCS_DURATION(_streams, _sgi, \
BW2VBPS(_bw, 117, 54, 26)))
#define VHT_GROUP(_streams, _sgi, _bw) \
__VHT_GROUP(_streams, _sgi, _bw, \
VHT_GROUP_SHIFT(_streams, _sgi, _bw))
#define CCK_DURATION(_bitrate, _short) \
(1000 * (10 /* SIFS */ + \
(_short ? 72 + 24 : 144 + 48) + \
(8 * (AVG_PKT_SIZE + 4) * 10) / (_bitrate)))
#define CCK_DURATION_LIST(_short, _s) \
CCK_DURATION(10, _short) >> _s, \
CCK_DURATION(20, _short) >> _s, \
CCK_DURATION(55, _short) >> _s, \
CCK_DURATION(110, _short) >> _s
#define __CCK_GROUP(_s) \
[MINSTREL_CCK_GROUP] = { \
.streams = 1, \
.flags = 0, \
.shift = _s, \
.duration = { \
CCK_DURATION_LIST(false, _s), \
CCK_DURATION_LIST(true, _s) \
} \
}
#define CCK_GROUP_SHIFT \
GROUP_SHIFT(CCK_DURATION(10, false))
#define CCK_GROUP __CCK_GROUP(CCK_GROUP_SHIFT)
#define OFDM_DURATION(_bitrate) \
(1000 * (16 /* SIFS + signal ext */ + \
16 /* T_PREAMBLE */ + \
4 /* T_SIGNAL */ + \
4 * (((16 + 80 * (AVG_PKT_SIZE + 4) + 6) / \
((_bitrate) * 4)))))
#define OFDM_DURATION_LIST(_s) \
OFDM_DURATION(60) >> _s, \
OFDM_DURATION(90) >> _s, \
OFDM_DURATION(120) >> _s, \
OFDM_DURATION(180) >> _s, \
OFDM_DURATION(240) >> _s, \
OFDM_DURATION(360) >> _s, \
OFDM_DURATION(480) >> _s, \
OFDM_DURATION(540) >> _s
#define __OFDM_GROUP(_s) \
[MINSTREL_OFDM_GROUP] = { \
.streams = 1, \
.flags = 0, \
.shift = _s, \
.duration = { \
OFDM_DURATION_LIST(_s), \
} \
}
#define OFDM_GROUP_SHIFT \
GROUP_SHIFT(OFDM_DURATION(60))
#define OFDM_GROUP __OFDM_GROUP(OFDM_GROUP_SHIFT)
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.");
/*
* 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.
*
* Sortorder has to be fixed for GROUP_IDX macro to be applicable:
* BW -> SGI -> #streams
*/
const struct mcs_group minstrel_mcs_groups[] = {
MCS_GROUP(1, 0, BW_20),
MCS_GROUP(2, 0, BW_20),
MCS_GROUP(3, 0, BW_20),
MCS_GROUP(4, 0, BW_20),
MCS_GROUP(1, 1, BW_20),
MCS_GROUP(2, 1, BW_20),
MCS_GROUP(3, 1, BW_20),
MCS_GROUP(4, 1, BW_20),
MCS_GROUP(1, 0, BW_40),
MCS_GROUP(2, 0, BW_40),
MCS_GROUP(3, 0, BW_40),
MCS_GROUP(4, 0, BW_40),
MCS_GROUP(1, 1, BW_40),
MCS_GROUP(2, 1, BW_40),
MCS_GROUP(3, 1, BW_40),
MCS_GROUP(4, 1, BW_40),
CCK_GROUP,
OFDM_GROUP,
VHT_GROUP(1, 0, BW_20),
VHT_GROUP(2, 0, BW_20),
VHT_GROUP(3, 0, BW_20),
VHT_GROUP(4, 0, BW_20),
VHT_GROUP(1, 1, BW_20),
VHT_GROUP(2, 1, BW_20),
VHT_GROUP(3, 1, BW_20),
VHT_GROUP(4, 1, BW_20),
VHT_GROUP(1, 0, BW_40),
VHT_GROUP(2, 0, BW_40),
VHT_GROUP(3, 0, BW_40),
VHT_GROUP(4, 0, BW_40),
VHT_GROUP(1, 1, BW_40),
VHT_GROUP(2, 1, BW_40),
VHT_GROUP(3, 1, BW_40),
VHT_GROUP(4, 1, BW_40),
VHT_GROUP(1, 0, BW_80),
VHT_GROUP(2, 0, BW_80),
VHT_GROUP(3, 0, BW_80),
VHT_GROUP(4, 0, BW_80),
VHT_GROUP(1, 1, BW_80),
VHT_GROUP(2, 1, BW_80),
VHT_GROUP(3, 1, BW_80),
VHT_GROUP(4, 1, BW_80),
};
const s16 minstrel_cck_bitrates[4] = { 10, 20, 55, 110 };
const s16 minstrel_ofdm_bitrates[8] = { 60, 90, 120, 180, 240, 360, 480, 540 };
static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
static const u8 minstrel_sample_seq[] = {
MINSTREL_SAMPLE_TYPE_INC,
MINSTREL_SAMPLE_TYPE_JUMP,
MINSTREL_SAMPLE_TYPE_INC,
MINSTREL_SAMPLE_TYPE_JUMP,
MINSTREL_SAMPLE_TYPE_INC,
MINSTREL_SAMPLE_TYPE_SLOW,
};
static void
minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
/*
* 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;
}
static bool
minstrel_ht_is_legacy_group(int group)
{
return group == MINSTREL_CCK_GROUP ||
group == MINSTREL_OFDM_GROUP;
}
/*
* Look up an MCS group index based on mac80211 rate information
*/
static int
minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
{
return GROUP_IDX((rate->idx / 8) + 1,
!!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
!!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
}
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));
}
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);
idx = rate->idx % 8;
goto out;
}
if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
group = minstrel_vht_get_group_idx(rate);
idx = ieee80211_rate_get_vht_mcs(rate);
goto out;
}
group = MINSTREL_CCK_GROUP;
for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++) {
if (rate->idx != mp->cck_rates[idx])
continue;
/* short preamble */
if ((mi->supported[group] & BIT(idx + 4)) &&
(rate->flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE))
idx += 4;
goto out;
}
group = MINSTREL_OFDM_GROUP;
for (idx = 0; idx < ARRAY_SIZE(mp->ofdm_rates[0]); idx++)
if (rate->idx == mp->ofdm_rates[mi->band][idx])
goto out;
idx = 0;
out:
return &mi->groups[group].rates[idx];
}
static inline struct minstrel_rate_stats *
minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
{
return &mi->groups[MI_RATE_GROUP(index)].rates[MI_RATE_IDX(index)];
}
static inline int minstrel_get_duration(int index)
{
const struct mcs_group *group = &minstrel_mcs_groups[MI_RATE_GROUP(index)];
unsigned int duration = group->duration[MI_RATE_IDX(index)];
return duration << group->shift;
}
static unsigned int
minstrel_ht_avg_ampdu_len(struct minstrel_ht_sta *mi)
{
int duration;
if (mi->avg_ampdu_len)
return MINSTREL_TRUNC(mi->avg_ampdu_len);
if (minstrel_ht_is_legacy_group(MI_RATE_GROUP(mi->max_tp_rate[0])))
return 1;
duration = minstrel_get_duration(mi->max_tp_rate[0]);
if (duration > 400 * 1000)
return 2;
if (duration > 250 * 1000)
return 4;
if (duration > 150 * 1000)
return 8;
return 16;
}
/*
* Return current throughput based on the average A-MPDU length, taking into
* account the expected number of retransmissions and their expected length
*/
int
minstrel_ht_get_tp_avg(struct minstrel_ht_sta *mi, int group, int rate,
int prob_avg)
{
unsigned int nsecs = 0, overhead = mi->overhead;
unsigned int ampdu_len = 1;
/* do not account throughput if success prob is below 10% */
if (prob_avg < MINSTREL_FRAC(10, 100))
return 0;
if (minstrel_ht_is_legacy_group(group))
overhead = mi->overhead_legacy;
else
ampdu_len = minstrel_ht_avg_ampdu_len(mi);
nsecs = 1000 * overhead / ampdu_len;
nsecs += minstrel_mcs_groups[group].duration[rate] <<
minstrel_mcs_groups[group].shift;
/*
* For the throughput calculation, limit the probability value to 90% to
* account for collision related packet error rate fluctuation
* (prob is scaled - see MINSTREL_FRAC above)
*/
if (prob_avg > MINSTREL_FRAC(90, 100))
prob_avg = MINSTREL_FRAC(90, 100);
return MINSTREL_TRUNC(100 * ((prob_avg * 1000000) / nsecs));
}
/*
* 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
minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u16 index,
u16 *tp_list)
{
int cur_group, cur_idx, cur_tp_avg, cur_prob;
int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
int j = MAX_THR_RATES;
cur_group = MI_RATE_GROUP(index);
cur_idx = MI_RATE_IDX(index);
cur_prob = mi->groups[cur_group].rates[cur_idx].prob_avg;
cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx, cur_prob);
do {
tmp_group = MI_RATE_GROUP(tp_list[j - 1]);
tmp_idx = MI_RATE_IDX(tp_list[j - 1]);
tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx,
tmp_prob);
if (cur_tp_avg < tmp_tp_avg ||
(cur_tp_avg == tmp_tp_avg && cur_prob <= tmp_prob))
break;
j--;
} while (j > 0);
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
minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 *dest, u16 index)
{
struct minstrel_mcs_group_data *mg;
struct minstrel_rate_stats *mrs;
int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
int max_tp_group, max_tp_idx, max_tp_prob;
int cur_tp_avg, cur_group, cur_idx;
int max_gpr_group, max_gpr_idx;
int max_gpr_tp_avg, max_gpr_prob;
cur_group = MI_RATE_GROUP(index);
cur_idx = MI_RATE_IDX(index);
mg = &mi->groups[cur_group];
mrs = &mg->rates[cur_idx];
tmp_group = MI_RATE_GROUP(*dest);
tmp_idx = MI_RATE_IDX(*dest);
tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
/* 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_RATE_GROUP(mi->max_tp_rate[0]);
max_tp_idx = MI_RATE_IDX(mi->max_tp_rate[0]);
max_tp_prob = mi->groups[max_tp_group].rates[max_tp_idx].prob_avg;
if (minstrel_ht_is_legacy_group(MI_RATE_GROUP(index)) &&
!minstrel_ht_is_legacy_group(max_tp_group))
return;
/* skip rates faster than max tp rate with lower prob */
if (minstrel_get_duration(mi->max_tp_rate[0]) > minstrel_get_duration(index) &&
mrs->prob_avg < max_tp_prob)
return;
max_gpr_group = MI_RATE_GROUP(mg->max_group_prob_rate);
max_gpr_idx = MI_RATE_IDX(mg->max_group_prob_rate);
max_gpr_prob = mi->groups[max_gpr_group].rates[max_gpr_idx].prob_avg;
if (mrs->prob_avg > MINSTREL_FRAC(75, 100)) {
cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx,
mrs->prob_avg);
if (cur_tp_avg > tmp_tp_avg)
*dest = index;
max_gpr_tp_avg = minstrel_ht_get_tp_avg(mi, max_gpr_group,
max_gpr_idx,
max_gpr_prob);
if (cur_tp_avg > max_gpr_tp_avg)
mg->max_group_prob_rate = index;
} else {
if (mrs->prob_avg > tmp_prob)
*dest = index;
if (mrs->prob_avg > max_gpr_prob)
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,
u16 tmp_mcs_tp_rate[MAX_THR_RATES],
u16 tmp_legacy_tp_rate[MAX_THR_RATES])
{
unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp, tmp_prob;
int i;
tmp_group = MI_RATE_GROUP(tmp_legacy_tp_rate[0]);
tmp_idx = MI_RATE_IDX(tmp_legacy_tp_rate[0]);
tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
tmp_cck_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
tmp_group = MI_RATE_GROUP(tmp_mcs_tp_rate[0]);
tmp_idx = MI_RATE_IDX(tmp_mcs_tp_rate[0]);
tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
tmp_mcs_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
if (tmp_cck_tp > tmp_mcs_tp) {
for(i = 0; i < MAX_THR_RATES; i++) {
minstrel_ht_sort_best_tp_rates(mi, tmp_legacy_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;
int tmp_max_streams, group, tmp_idx, tmp_prob;
int tmp_tp = 0;
if (!mi->sta->ht_cap.ht_supported)
return;
group = MI_RATE_GROUP(mi->max_tp_rate[0]);
tmp_max_streams = minstrel_mcs_groups[group].streams;
for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
mg = &mi->groups[group];
if (!mi->supported[group] || group == MINSTREL_CCK_GROUP)
continue;
tmp_idx = MI_RATE_IDX(mg->max_group_prob_rate);
tmp_prob = mi->groups[group].rates[tmp_idx].prob_avg;
if (tmp_tp < minstrel_ht_get_tp_avg(mi, group, tmp_idx, tmp_prob) &&
(minstrel_mcs_groups[group].streams < tmp_max_streams)) {
mi->max_prob_rate = mg->max_group_prob_rate;
tmp_tp = minstrel_ht_get_tp_avg(mi, group,
tmp_idx,
tmp_prob);
}
}
}
static u16
__minstrel_ht_get_sample_rate(struct minstrel_ht_sta *mi,
enum minstrel_sample_type type)
{
u16 *rates = mi->sample[type].sample_rates;
u16 cur;
int i;
for (i = 0; i < MINSTREL_SAMPLE_RATES; i++) {
if (!rates[i])
continue;
cur = rates[i];
rates[i] = 0;
return cur;
}
return 0;
}
static inline int
minstrel_ewma(int old, int new, int weight)
{
int diff, incr;
diff = new - old;
incr = (EWMA_DIV - weight) * diff / EWMA_DIV;
return old + incr;
}
static inline int minstrel_filter_avg_add(u16 *prev_1, u16 *prev_2, s32 in)
{
s32 out_1 = *prev_1;
s32 out_2 = *prev_2;
s32 val;
if (!in)
in += 1;
if (!out_1) {
val = out_1 = in;
goto out;
}
val = MINSTREL_AVG_COEFF1 * in;
val += MINSTREL_AVG_COEFF2 * out_1;
val += MINSTREL_AVG_COEFF3 * out_2;
val >>= MINSTREL_SCALE;
if (val > 1 << MINSTREL_SCALE)
val = 1 << MINSTREL_SCALE;
if (val < 0)
val = 1;
out:
*prev_2 = out_1;
*prev_1 = val;
return val;
}
/*
* Recalculate statistics and counters of a given rate
*/
static void
minstrel_ht_calc_rate_stats(struct minstrel_priv *mp,
struct minstrel_rate_stats *mrs)
{
unsigned int cur_prob;
if (unlikely(mrs->attempts > 0)) {
cur_prob = MINSTREL_FRAC(mrs->success, mrs->attempts);
minstrel_filter_avg_add(&mrs->prob_avg,
&mrs->prob_avg_1, cur_prob);
mrs->att_hist += mrs->attempts;
mrs->succ_hist += mrs->success;
}
mrs->last_success = mrs->success;
mrs->last_attempts = mrs->attempts;
mrs->success = 0;
mrs->attempts = 0;
}
static bool
minstrel_ht_find_sample_rate(struct minstrel_ht_sta *mi, int type, int idx)
{
int i;
for (i = 0; i < MINSTREL_SAMPLE_RATES; i++) {
u16 cur = mi->sample[type].sample_rates[i];
if (cur == idx)
return true;
if (!cur)
break;
}
return false;
}
static int
minstrel_ht_move_sample_rates(struct minstrel_ht_sta *mi, int type,
u32 fast_rate_dur, u32 slow_rate_dur)
{
u16 *rates = mi->sample[type].sample_rates;
int i, j;
for (i = 0, j = 0; i < MINSTREL_SAMPLE_RATES; i++) {
u32 duration;
bool valid = false;
u16 cur;
cur = rates[i];
if (!cur)
continue;
duration = minstrel_get_duration(cur);
switch (type) {
case MINSTREL_SAMPLE_TYPE_SLOW:
valid = duration > fast_rate_dur &&
duration < slow_rate_dur;
break;
case MINSTREL_SAMPLE_TYPE_INC:
case MINSTREL_SAMPLE_TYPE_JUMP:
valid = duration < fast_rate_dur;
break;
default:
valid = false;
break;
}
if (!valid) {
rates[i] = 0;
continue;
}
if (i == j)
continue;
rates[j++] = cur;
rates[i] = 0;
}
return j;
}
static int
minstrel_ht_group_min_rate_offset(struct minstrel_ht_sta *mi, int group,
u32 max_duration)
{
u16 supported = mi->supported[group];
int i;
for (i = 0; i < MCS_GROUP_RATES && supported; i++, supported >>= 1) {
if (!(supported & BIT(0)))
continue;
if (minstrel_get_duration(MI_RATE(group, i)) >= max_duration)
continue;
return i;
}
return -1;
}
/*
* Incremental update rates:
* Flip through groups and pick the first group rate that is faster than the
* highest currently selected rate
*/
static u16
minstrel_ht_next_inc_rate(struct minstrel_ht_sta *mi, u32 fast_rate_dur)
{
u8 type = MINSTREL_SAMPLE_TYPE_INC;
int i, index = 0;
u8 group;
group = mi->sample[type].sample_group;
for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) {
group = (group + 1) % ARRAY_SIZE(minstrel_mcs_groups);
index = minstrel_ht_group_min_rate_offset(mi, group,
fast_rate_dur);
if (index < 0)
continue;
index = MI_RATE(group, index & 0xf);
if (!minstrel_ht_find_sample_rate(mi, type, index))
goto out;
}
index = 0;
out:
mi->sample[type].sample_group = group;
return index;
}
static int
minstrel_ht_next_group_sample_rate(struct minstrel_ht_sta *mi, int group,
u16 supported, int offset)
{
struct minstrel_mcs_group_data *mg = &mi->groups[group];
u16 idx;
int i;
for (i = 0; i < MCS_GROUP_RATES; i++) {
idx = sample_table[mg->column][mg->index];
if (++mg->index >= MCS_GROUP_RATES) {
mg->index = 0;
if (++mg->column >= ARRAY_SIZE(sample_table))
mg->column = 0;
}
if (idx < offset)
continue;
if (!(supported & BIT(idx)))
continue;
return MI_RATE(group, idx);
}
return -1;
}
/*
* Jump rates:
* Sample random rates, use those that are faster than the highest
* currently selected rate. Rates between the fastest and the slowest
* get sorted into the slow sample bucket, but only if it has room
*/
static u16
minstrel_ht_next_jump_rate(struct minstrel_ht_sta *mi, u32 fast_rate_dur,
u32 slow_rate_dur, int *slow_rate_ofs)
{
struct minstrel_rate_stats *mrs;
u32 max_duration = slow_rate_dur;
int i, index, offset;
u16 *slow_rates;
u16 supported;
u32 duration;
u8 group;
if (*slow_rate_ofs >= MINSTREL_SAMPLE_RATES)
max_duration = fast_rate_dur;
slow_rates = mi->sample[MINSTREL_SAMPLE_TYPE_SLOW].sample_rates;
group = mi->sample[MINSTREL_SAMPLE_TYPE_JUMP].sample_group;
for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) {
u8 type;
group = (group + 1) % ARRAY_SIZE(minstrel_mcs_groups);
supported = mi->supported[group];
if (!supported)
continue;
offset = minstrel_ht_group_min_rate_offset(mi, group,
max_duration);
if (offset < 0)
continue;
index = minstrel_ht_next_group_sample_rate(mi, group, supported,
offset);
if (index < 0)
continue;
duration = minstrel_get_duration(index);
if (duration < fast_rate_dur)
type = MINSTREL_SAMPLE_TYPE_JUMP;
else
type = MINSTREL_SAMPLE_TYPE_SLOW;
if (minstrel_ht_find_sample_rate(mi, type, index))
continue;
if (type == MINSTREL_SAMPLE_TYPE_JUMP)
goto found;
if (*slow_rate_ofs >= MINSTREL_SAMPLE_RATES)
continue;
if (duration >= slow_rate_dur)
continue;
/* skip slow rates with high success probability */
mrs = minstrel_get_ratestats(mi, index);
if (mrs->prob_avg > MINSTREL_FRAC(95, 100))
continue;
slow_rates[(*slow_rate_ofs)++] = index;
if (*slow_rate_ofs >= MINSTREL_SAMPLE_RATES)
max_duration = fast_rate_dur;
}
index = 0;
found:
mi->sample[MINSTREL_SAMPLE_TYPE_JUMP].sample_group = group;
return index;
}
static void
minstrel_ht_refill_sample_rates(struct minstrel_ht_sta *mi)
{
u32 prob_dur = minstrel_get_duration(mi->max_prob_rate);
u32 tp_dur = minstrel_get_duration(mi->max_tp_rate[0]);
u32 tp2_dur = minstrel_get_duration(mi->max_tp_rate[1]);
u32 fast_rate_dur = min(min(tp_dur, tp2_dur), prob_dur);
u32 slow_rate_dur = max(max(tp_dur, tp2_dur), prob_dur);
u16 *rates;
int i, j;
rates = mi->sample[MINSTREL_SAMPLE_TYPE_INC].sample_rates;
i = minstrel_ht_move_sample_rates(mi, MINSTREL_SAMPLE_TYPE_INC,
fast_rate_dur, slow_rate_dur);
while (i < MINSTREL_SAMPLE_RATES) {
rates[i] = minstrel_ht_next_inc_rate(mi, tp_dur);
if (!rates[i])
break;
i++;
}
rates = mi->sample[MINSTREL_SAMPLE_TYPE_JUMP].sample_rates;
i = minstrel_ht_move_sample_rates(mi, MINSTREL_SAMPLE_TYPE_JUMP,
fast_rate_dur, slow_rate_dur);
j = minstrel_ht_move_sample_rates(mi, MINSTREL_SAMPLE_TYPE_SLOW,
fast_rate_dur, slow_rate_dur);
while (i < MINSTREL_SAMPLE_RATES) {
rates[i] = minstrel_ht_next_jump_rate(mi, fast_rate_dur,
slow_rate_dur, &j);
if (!rates[i])
break;
i++;
}
for (i = 0; i < ARRAY_SIZE(mi->sample); i++)
memcpy(mi->sample[i].cur_sample_rates, mi->sample[i].sample_rates,
sizeof(mi->sample[i].cur_sample_rates));
}
/*
* 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
* - as long as the max prob rate has a probability of more than 75%, pick
* 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 *mrs;
int group, i, j, cur_prob;
u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
u16 tmp_legacy_tp_rate[MAX_THR_RATES], tmp_max_prob_rate;
u16 index;
bool ht_supported = mi->sta->ht_cap.ht_supported;
if (mi->ampdu_packets > 0) {
if (!ieee80211_hw_check(mp->hw, TX_STATUS_NO_AMPDU_LEN))
mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,