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// SPDX-License-Identifier: ISC
/*
* Copyright (C) 2019 Felix Fietkau <nbd@nbd.name>
*/
#include "mt76.h"
#define AVG_PKT_SIZE 1024
/* 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) DIV_ROUND_UP(MCS_NBITS, (bps))
/* Transmission time (1024 usec) for a packet containing (syms) * symbols */
#define MCS_SYMBOL_TIME(sgi, syms) \
(sgi ? \
((syms) * 18 * 1024 + 4 * 1024) / 5 : /* syms * 3.6 us */ \
((syms) * 1024) << 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 BW_20 0
#define BW_40 1
#define BW_80 2
/*
* Define group sort order: HT40 -> SGI -> #streams
*/
#define MT_MAX_STREAMS 4
#define MT_HT_STREAM_GROUPS 4 /* BW(=2) * SGI(=2) */
#define MT_VHT_STREAM_GROUPS 6 /* BW(=3) * SGI(=2) */
#define MT_HT_GROUPS_NB (MT_MAX_STREAMS * \
MT_HT_STREAM_GROUPS)
#define MT_VHT_GROUPS_NB (MT_MAX_STREAMS * \
MT_VHT_STREAM_GROUPS)
#define MT_GROUPS_NB (MT_HT_GROUPS_NB + \
MT_VHT_GROUPS_NB)
#define MT_HT_GROUP_0 0
#define MT_VHT_GROUP_0 (MT_HT_GROUP_0 + MT_HT_GROUPS_NB)
#define MCS_GROUP_RATES 10
#define HT_GROUP_IDX(_streams, _sgi, _ht40) \
MT_HT_GROUP_0 + \
MT_MAX_STREAMS * 2 * _ht40 + \
MT_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) \
[HT_GROUP_IDX(_streams, _sgi, _ht40)] = { \
.shift = _s, \
.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) \
(MT_VHT_GROUP_0 + \
MT_MAX_STREAMS * 2 * (_bw) + \
MT_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)] = { \
.shift = _s, \
.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))
struct mcs_group {
u8 shift;
u16 duration[MCS_GROUP_RATES];
};
static const struct mcs_group airtime_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),
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),
};
static u32
mt76_calc_legacy_rate_duration(const struct ieee80211_rate *rate, bool short_pre,
int len)
{
u32 duration;
switch (rate->hw_value >> 8) {
case MT_PHY_TYPE_CCK:
duration = 144 + 48; /* preamble + PLCP */
if (short_pre)
duration >>= 1;
duration += 10; /* SIFS */
break;
case MT_PHY_TYPE_OFDM:
duration = 20 + 16; /* premable + SIFS */
break;
default:
WARN_ON_ONCE(1);
return 0;
}
len <<= 3;
duration += (len * 10) / rate->bitrate;
return duration;
}
u32 mt76_calc_rx_airtime(struct mt76_dev *dev, struct mt76_rx_status *status,
int len)
{
struct ieee80211_supported_band *sband;
const struct ieee80211_rate *rate;
bool sgi = status->enc_flags & RX_ENC_FLAG_SHORT_GI;
bool sp = status->enc_flags & RX_ENC_FLAG_SHORTPRE;
int bw, streams;
u32 duration;
int group, idx;
switch (status->bw) {
case RATE_INFO_BW_20:
bw = BW_20;
break;
case RATE_INFO_BW_40:
bw = BW_40;
break;
case RATE_INFO_BW_80:
bw = BW_80;
break;
default:
WARN_ON_ONCE(1);
return 0;
}
switch (status->encoding) {
case RX_ENC_LEGACY:
if (WARN_ON_ONCE(status->band > NL80211_BAND_5GHZ))
return 0;
sband = dev->hw->wiphy->bands[status->band];
if (!sband || status->rate_idx >= sband->n_bitrates)
return 0;
rate = &sband->bitrates[status->rate_idx];
return mt76_calc_legacy_rate_duration(rate, sp, len);
case RX_ENC_VHT:
streams = status->nss;
idx = status->rate_idx;
group = VHT_GROUP_IDX(streams, sgi, bw);
break;
case RX_ENC_HT:
streams = ((status->rate_idx >> 3) & 3) + 1;
idx = status->rate_idx & 7;
group = HT_GROUP_IDX(streams, sgi, bw);
break;
default:
WARN_ON_ONCE(1);
return 0;
}
if (WARN_ON_ONCE(streams > 4))
return 0;
duration = airtime_mcs_groups[group].duration[idx];
duration <<= airtime_mcs_groups[group].shift;
duration *= len;
duration /= AVG_PKT_SIZE;
duration /= 1024;
duration += 36 + (streams << 2);
return duration;
}
u32 mt76_calc_tx_airtime(struct mt76_dev *dev, struct ieee80211_tx_info *info,
int len)
{
struct mt76_rx_status stat = {
.band = info->band,
};
u32 duration = 0;
int i;
for (i = 0; i < ARRAY_SIZE(info->status.rates); i++) {
struct ieee80211_tx_rate *rate = &info->status.rates[i];
u32 cur_duration;
if (rate->idx < 0 || !rate->count)
break;
if (rate->flags & IEEE80211_TX_RC_80_MHZ_WIDTH)
stat.bw = RATE_INFO_BW_80;
else if (rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
stat.bw = RATE_INFO_BW_40;
else
stat.bw = RATE_INFO_BW_20;
stat.enc_flags = 0;
if (rate->flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE)
stat.enc_flags |= RX_ENC_FLAG_SHORTPRE;
if (rate->flags & IEEE80211_TX_RC_SHORT_GI)
stat.enc_flags |= RX_ENC_FLAG_SHORT_GI;
stat.rate_idx = rate->idx;
if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
stat.encoding = RX_ENC_VHT;
stat.rate_idx = ieee80211_rate_get_vht_mcs(rate);
stat.nss = ieee80211_rate_get_vht_nss(rate);
} else if (rate->flags & IEEE80211_TX_RC_MCS) {
stat.encoding = RX_ENC_HT;
} else {
stat.encoding = RX_ENC_LEGACY;
}
cur_duration = mt76_calc_rx_airtime(dev, &stat, len);
duration += cur_duration * rate->count;
}
return duration;
}
EXPORT_SYMBOL_GPL(mt76_calc_tx_airtime);
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