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linux/net/mac80211/rc80211_minstrel_ht.c
Johannes Berg 64f68e5d15 mac80211: remove channel type argument from rate_update 
The channel type argument to the rate_update()
callback isn't really the correct way to give
the rate control algorithm about the desired
RX bandwidth of the peer.

Remove this argument, and instead update the
STA capabilities with 20/40 appropriately. The
SMPS update done by this callback works in the
same way, so this makes the callback cleaner.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2012-04-10 14:54:08 -04:00

905 lines
23 KiB
C
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/*
* Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
*
* 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>
#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
#define SAMPLE_COLUMNS 10
#define EWMA_LEVEL 75
/* 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 */
#define MCS_NSYMS(bps) ((MCS_NBITS + (bps) - 1) / (bps))
/* Transmission time for a packet containing (syms) symbols */
#define MCS_SYMBOL_TIME(sgi, syms) \
(sgi ? \
((syms) * 18 + 4) / 5 : /* syms * 3.6 us */ \
(syms) << 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)))
/*
* Define group sort order: HT40 -> SGI -> #streams
*/
#define GROUP_IDX(_streams, _sgi, _ht40) \
MINSTREL_MAX_STREAMS * 2 * _ht40 + \
MINSTREL_MAX_STREAMS * _sgi + \
_streams - 1
/* MCS rate information for an MCS group */
#define MCS_GROUP(_streams, _sgi, _ht40) \
[GROUP_IDX(_streams, _sgi, _ht40)] = { \
.streams = _streams, \
.flags = \
(_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) \
} \
}
/*
* 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:
* HT40 -> SGI -> #streams
*/
const struct mcs_group minstrel_mcs_groups[] = {
MCS_GROUP(1, 0, 0),
MCS_GROUP(2, 0, 0),
#if MINSTREL_MAX_STREAMS >= 3
MCS_GROUP(3, 0, 0),
#endif
MCS_GROUP(1, 1, 0),
MCS_GROUP(2, 1, 0),
#if MINSTREL_MAX_STREAMS >= 3
MCS_GROUP(3, 1, 0),
#endif
MCS_GROUP(1, 0, 1),
MCS_GROUP(2, 0, 1),
#if MINSTREL_MAX_STREAMS >= 3
MCS_GROUP(3, 0, 1),
#endif
MCS_GROUP(1, 1, 1),
MCS_GROUP(2, 1, 1),
#if MINSTREL_MAX_STREAMS >= 3
MCS_GROUP(3, 1, 1),
#endif
};
static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES];
/*
* Perform EWMA (Exponentially Weighted Moving Average) calculation
*/
static int
minstrel_ewma(int old, int new, int weight)
{
return (new * (100 - weight) + old * weight) / 100;
}
/*
* 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 / MCS_GROUP_RATES) + 1,
!!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
!!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
}
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
minstrel_calc_rate_ewma(struct minstrel_rate_stats *mr)
{
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
minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
{
struct minstrel_rate_stats *mr;
unsigned int usecs;
mr = &mi->groups[group].rates[rate];
if (mr->probability < MINSTREL_FRAC(1, 10)) {
mr->cur_tp = 0;
return;
}
usecs = mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
usecs += minstrel_mcs_groups[group].duration[rate];
mr->cur_tp = MINSTREL_TRUNC((1000000 / usecs) * mr->probability);
}
/*
* 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 3/4, 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 *mr;
int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
int group, i, index;
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;
mi->max_tp_rate = 0;
mi->max_tp_rate2 = 0;
mi->max_prob_rate = 0;
for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
cur_prob = 0;
cur_prob_tp = 0;
cur_tp = 0;
cur_tp2 = 0;
mg = &mi->groups[group];
if (!mg->supported)
continue;
mg->max_tp_rate = 0;
mg->max_tp_rate2 = 0;
mg->max_prob_rate = 0;
mi->sample_count++;
for (i = 0; i < MCS_GROUP_RATES; i++) {
if (!(mg->supported & BIT(i)))
continue;
mr = &mg->rates[i];
mr->retry_updated = false;
index = MCS_GROUP_RATES * group + i;
minstrel_calc_rate_ewma(mr);
minstrel_ht_calc_tp(mi, group, i);
if (!mr->cur_tp)
continue;
/* ignore the lowest rate of each single-stream group */
if (!i && minstrel_mcs_groups[group].streams == 1)
continue;
if ((mr->cur_tp > cur_prob_tp && mr->probability >
MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
mg->max_prob_rate = index;
cur_prob = mr->probability;
cur_prob_tp = mr->cur_tp;
}
if (mr->cur_tp > cur_tp) {
swap(index, mg->max_tp_rate);
cur_tp = mr->cur_tp;
mr = minstrel_get_ratestats(mi, index);
}
if (index >= mg->max_tp_rate)
continue;
if (mr->cur_tp > cur_tp2) {
mg->max_tp_rate2 = index;
cur_tp2 = mr->cur_tp;
}
}
}
/* try to sample up to half of the available rates during each interval */
mi->sample_count *= 4;
cur_prob = 0;
cur_prob_tp = 0;
cur_tp = 0;
cur_tp2 = 0;
for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
mg = &mi->groups[group];
if (!mg->supported)
continue;
mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
if (cur_prob_tp < mr->cur_tp &&
minstrel_mcs_groups[group].streams == 1) {
mi->max_prob_rate = mg->max_prob_rate;
cur_prob = mr->cur_prob;
cur_prob_tp = mr->cur_tp;
}
mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
if (cur_tp < mr->cur_tp) {
mi->max_tp_rate2 = mi->max_tp_rate;
cur_tp2 = cur_tp;
mi->max_tp_rate = mg->max_tp_rate;
cur_tp = mr->cur_tp;
}
mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
if (cur_tp2 < mr->cur_tp) {
mi->max_tp_rate2 = mg->max_tp_rate2;
cur_tp2 = mr->cur_tp;
}
}
mi->stats_update = jiffies;
}
static bool
minstrel_ht_txstat_valid(struct ieee80211_tx_rate *rate)
{
if (rate->idx < 0)
return false;
if (!rate->count)
return false;
return !!(rate->flags & IEEE80211_TX_RC_MCS);
}
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
minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx,
bool primary)
{
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)
*idx = mi->groups[group].max_tp_rate;
else
*idx = mi->groups[group].max_tp_rate2;
break;
}
}
static void
minstrel_aggr_check(struct ieee80211_sta *pubsta, struct sk_buff *skb)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
u16 tid;
if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
return;
if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
return;
tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
if (likely(sta->ampdu_mlme.tid_tx[tid]))
return;
if (skb_get_queue_mapping(skb) == IEEE80211_AC_VO)
return;
ieee80211_start_tx_ba_session(pubsta, tid, 5000);
}
static void
minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
struct ieee80211_sta *sta, void *priv_sta,
struct sk_buff *skb)
{
struct minstrel_ht_sta_priv *msp = priv_sta;
struct minstrel_ht_sta *mi = &msp->ht;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct ieee80211_tx_rate *ar = info->status.rates;
struct minstrel_rate_stats *rate, *rate2;
struct minstrel_priv *mp = priv;
bool last = false;
int group;
int i = 0;
if (!msp->is_ht)
return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
/* This packet was aggregated but doesn't carry status info */
if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
!(info->flags & IEEE80211_TX_STAT_AMPDU))
return;
if (!(info->flags & IEEE80211_TX_STAT_AMPDU)) {
info->status.ampdu_ack_len =
(info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
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) {
mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
mi->sample_tries = 2;
mi->sample_count--;
}
if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
mi->sample_packets += info->status.ampdu_len;
for (i = 0; !last; i++) {
last = (i == IEEE80211_TX_MAX_RATES - 1) ||
!minstrel_ht_txstat_valid(&ar[i + 1]);
if (!minstrel_ht_txstat_valid(&ar[i]))
break;
group = minstrel_ht_get_group_idx(&ar[i]);
rate = &mi->groups[group].rates[ar[i].idx % 8];
if (last)
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.
*/
rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
if (rate->attempts > 30 &&
MINSTREL_FRAC(rate->success, rate->attempts) <
MINSTREL_FRAC(20, 100))
minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
if (rate2->attempts > 30 &&
MINSTREL_FRAC(rate2->success, rate2->attempts) <
MINSTREL_FRAC(20, 100))
minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
minstrel_ht_update_stats(mp, mi);
if (!(info->flags & IEEE80211_TX_CTL_AMPDU))
minstrel_aggr_check(sta, skb);
}
}
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;
unsigned int ctime = 0;
unsigned int t_slot = 9; /* FIXME */
unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
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];
tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len;
/* 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);
/* Total TX time for data and Contention after first 2 tries */
tx_time = ctime + 2 * (mi->overhead + tx_time_data);
tx_time_rtscts = ctime + 2 * (mi->overhead_rtscts + tx_time_data);
/* See how many more tries we can fit inside segment size */
do {
/* Contention time for this try */
ctime = (t_slot * cw) >> 1;
cw = min((cw << 1) | 1, mp->cw_max);
/* Total TX time after this try */
tx_time += ctime + mi->overhead + tx_time_data;
tx_time_rtscts += ctime + mi->overhead_rtscts + tx_time_data;
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,
struct ieee80211_tx_rate *rate, int index,
bool sample, bool rtscts)
{
const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
struct minstrel_rate_stats *mr;
mr = minstrel_get_ratestats(mi, index);
if (!mr->retry_updated)
minstrel_calc_retransmit(mp, mi, index);
if (sample)
rate->count = 1;
else if (mr->probability < MINSTREL_FRAC(20, 100))
rate->count = 2;
else if (rtscts)
rate->count = mr->retry_count_rtscts;
else
rate->count = mr->retry_count;
rate->flags = IEEE80211_TX_RC_MCS | group->flags;
if (rtscts)
rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS;
rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES;
}
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;
int sample_idx = 0;
if (mi->sample_wait > 0) {
mi->sample_wait--;
return -1;
}
if (!mi->sample_tries)
return -1;
mi->sample_tries--;
mg = &mi->groups[mi->sample_group];
sample_idx = sample_table[mg->column][mg->index];
mr = &mg->rates[sample_idx];
sample_idx += mi->sample_group * MCS_GROUP_RATES;
minstrel_next_sample_idx(mi);
/*
* Sampling might add some overhead (RTS, no aggregation)
* to the frame. Hence, don't use sampling for the currently
* used max TP rate.
*/
if (sample_idx == mi->max_tp_rate)
return -1;
/*
* When not using MRR, do not sample if the probability is already
* higher than 95% to avoid wasting airtime
*/
if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100)))
return -1;
/*
* Make sure that lower rates get sampled only occasionally,
* if the link is working perfectly.
*/
if (minstrel_get_duration(sample_idx) >
minstrel_get_duration(mi->max_tp_rate)) {
if (mr->sample_skipped < 20)
return -1;
if (mi->sample_slow++ > 2)
return -1;
}
return sample_idx;
}
static void
minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
struct ieee80211_tx_rate_control *txrc)
{
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
struct ieee80211_tx_rate *ar = info->status.rates;
struct minstrel_ht_sta_priv *msp = priv_sta;
struct minstrel_ht_sta *mi = &msp->ht;
struct minstrel_priv *mp = priv;
int sample_idx;
bool sample = false;
if (rate_control_send_low(sta, priv_sta, txrc))
return;
if (!msp->is_ht)
return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
info->flags |= mi->tx_flags;
/* Don't use EAPOL frames for sampling on non-mrr hw */
if (mp->hw->max_rates == 1 &&
txrc->skb->protocol == cpu_to_be16(ETH_P_PAE))
sample_idx = -1;
else
sample_idx = minstrel_get_sample_rate(mp, mi);
#ifdef CONFIG_MAC80211_DEBUGFS
/* use fixed index if set */
if (mp->fixed_rate_idx != -1)
sample_idx = mp->fixed_rate_idx;
#endif
if (sample_idx >= 0) {
sample = true;
minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
true, false);
info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
} else {
minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
false, false);
}
if (mp->hw->max_rates >= 3) {
/*
* At least 3 tx rates supported, use
* sample_rate -> max_tp_rate -> max_prob_rate for sampling and
* max_tp_rate -> max_tp_rate2 -> max_prob_rate by default.
*/
if (sample_idx >= 0)
minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
false, false);
else
minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2,
false, true);
minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate,
false, !sample);
ar[3].count = 0;
ar[3].idx = -1;
} else if (mp->hw->max_rates == 2) {
/*
* Only 2 tx rates supported, use
* sample_rate -> max_prob_rate for sampling and
* max_tp_rate -> max_prob_rate by default.
*/
minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_prob_rate,
false, !sample);
ar[2].count = 0;
ar[2].idx = -1;
} else {
/* Not using MRR, only use the first rate */
ar[1].count = 0;
ar[1].idx = -1;
}
mi->total_packets++;
/* wraparound */
if (mi->total_packets == ~0) {
mi->total_packets = 0;
mi->sample_packets = 0;
}
}
static void
minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
struct ieee80211_sta *sta, void *priv_sta)
{
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;
struct ieee80211_local *local = hw_to_local(mp->hw);
u16 sta_cap = sta->ht_cap.cap;
int n_supported = 0;
int ack_dur;
int stbc;
int i;
unsigned int smps;
/* fall back to the old minstrel for legacy stations */
if (!sta->ht_cap.ht_supported)
goto use_legacy;
BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS);
msp->is_ht = true;
memset(mi, 0, sizeof(*mi));
mi->stats_update = jiffies;
ack_dur = ieee80211_frame_duration(local, 10, 60, 1, 1);
mi->overhead = ieee80211_frame_duration(local, 0, 60, 1, 1) + ack_dur;
mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
/* When using MRR, sample more on the first attempt, without delay */
if (mp->has_mrr) {
mi->sample_count = 16;
mi->sample_wait = 0;
} else {
mi->sample_count = 8;
mi->sample_wait = 8;
}
mi->sample_tries = 4;
stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
IEEE80211_HT_CAP_RX_STBC_SHIFT;
mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
smps = (sta_cap & IEEE80211_HT_CAP_SM_PS) >>
IEEE80211_HT_CAP_SM_PS_SHIFT;
for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
u16 req = 0;
mi->groups[i].supported = 0;
if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
req |= IEEE80211_HT_CAP_SGI_40;
else
req |= IEEE80211_HT_CAP_SGI_20;
}
if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
req |= IEEE80211_HT_CAP_SUP_WIDTH_20_40;
if ((sta_cap & req) != req)
continue;
/* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
if (smps == WLAN_HT_CAP_SM_PS_STATIC &&
minstrel_mcs_groups[i].streams > 1)
continue;
mi->groups[i].supported =
mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
if (mi->groups[i].supported)
n_supported++;
}
if (!n_supported)
goto use_legacy;
return;
use_legacy:
msp->is_ht = false;
memset(&msp->legacy, 0, sizeof(msp->legacy));
msp->legacy.r = msp->ratelist;
msp->legacy.sample_table = msp->sample_table;
return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy);
}
static void
minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
struct ieee80211_sta *sta, void *priv_sta)
{
minstrel_ht_update_caps(priv, sband, sta, priv_sta);
}
static void
minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
struct ieee80211_sta *sta, void *priv_sta,
u32 changed)
{
minstrel_ht_update_caps(priv, sband, sta, priv_sta);
}
static void *
minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
{
struct ieee80211_supported_band *sband;
struct minstrel_ht_sta_priv *msp;
struct minstrel_priv *mp = priv;
struct ieee80211_hw *hw = mp->hw;
int max_rates = 0;
int i;
for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
sband = hw->wiphy->bands[i];
if (sband && sband->n_bitrates > max_rates)
max_rates = sband->n_bitrates;
}
msp = kzalloc(sizeof(struct minstrel_ht_sta), gfp);
if (!msp)
return NULL;
msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
if (!msp->ratelist)
goto error;
msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
if (!msp->sample_table)
goto error1;
return msp;
error1:
kfree(msp->ratelist);
error:
kfree(msp);
return NULL;
}
static void
minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
{
struct minstrel_ht_sta_priv *msp = priv_sta;
kfree(msp->sample_table);
kfree(msp->ratelist);
kfree(msp);
}
static void *
minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
{
return mac80211_minstrel.alloc(hw, debugfsdir);
}
static void
minstrel_ht_free(void *priv)
{
mac80211_minstrel.free(priv);
}
static struct rate_control_ops mac80211_minstrel_ht = {
.name = "minstrel_ht",
.tx_status = minstrel_ht_tx_status,
.get_rate = minstrel_ht_get_rate,
.rate_init = minstrel_ht_rate_init,
.rate_update = minstrel_ht_rate_update,
.alloc_sta = minstrel_ht_alloc_sta,
.free_sta = minstrel_ht_free_sta,
.alloc = minstrel_ht_alloc,
.free = minstrel_ht_free,
#ifdef CONFIG_MAC80211_DEBUGFS
.add_sta_debugfs = minstrel_ht_add_sta_debugfs,
.remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
#endif
};
static void
init_sample_table(void)
{
int col, i, new_idx;
u8 rnd[MCS_GROUP_RATES];
memset(sample_table, 0xff, sizeof(sample_table));
for (col = 0; col < SAMPLE_COLUMNS; col++) {
for (i = 0; i < MCS_GROUP_RATES; i++) {
get_random_bytes(rnd, sizeof(rnd));
new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
while (sample_table[col][new_idx] != 0xff)
new_idx = (new_idx + 1) % MCS_GROUP_RATES;
sample_table[col][new_idx] = i;
}
}
}
int __init
rc80211_minstrel_ht_init(void)
{
init_sample_table();
return ieee80211_rate_control_register(&mac80211_minstrel_ht);
}
void
rc80211_minstrel_ht_exit(void)
{
ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
}
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