diff options
Diffstat (limited to 'net/mac80211/rc80211_minstrel_ht.c')
| -rw-r--r-- | net/mac80211/rc80211_minstrel_ht.c | 1756 |
1 files changed, 1756 insertions, 0 deletions
diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c new file mode 100644 index 0000000..2888011 --- /dev/null +++ b/net/mac80211/rc80211_minstrel_ht.c @@ -0,0 +1,1756 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org> + */ +#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.h" +#include "rc80211_minstrel_ht.h" + +#define AVG_AMPDU_SIZE 16 +#define AVG_PKT_SIZE 1200 + +#define SAMPLE_SWITCH_THR 100 + +/* 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, _len) \ + (1000 * (10 /* SIFS */ + \ + (_short ? 72 + 24 : 144 + 48) + \ + (8 * (_len + 4) * 10) / (_bitrate))) + +#define CCK_ACK_DURATION(_bitrate, _short) \ + (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) + \ + CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE)) + +#define CCK_DURATION_LIST(_short, _s) \ + CCK_ACK_DURATION(10, _short) >> _s, \ + CCK_ACK_DURATION(20, _short) >> _s, \ + CCK_ACK_DURATION(55, _short) >> _s, \ + CCK_ACK_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_ACK_DURATION(10, false)) + +#define CCK_GROUP __CCK_GROUP(CCK_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, + + 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 u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly; + +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; +} + +/* + * 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; + } else if (rate->flags & IEEE80211_TX_RC_VHT_MCS) { + group = minstrel_vht_get_group_idx(rate); + idx = ieee80211_rate_get_vht_mcs(rate); + } else { + group = MINSTREL_CCK_GROUP; + + for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++) + if (rate->idx == mp->cck_rates[idx]) + break; + + /* short preamble */ + if ((mi->supported[group] & BIT(idx + 4)) && + (rate->flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE)) + idx += 4; + } + 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[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES]; +} + +static unsigned int +minstrel_ht_avg_ampdu_len(struct minstrel_ht_sta *mi) +{ + if (!mi->avg_ampdu_len) + return AVG_AMPDU_SIZE; + + return MINSTREL_TRUNC(mi->avg_ampdu_len); +} + +/* + * 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_ewma) +{ + unsigned int nsecs = 0; + + /* do not account throughput if sucess prob is below 10% */ + if (prob_ewma < MINSTREL_FRAC(10, 100)) + return 0; + + if (group != MINSTREL_CCK_GROUP) + nsecs = 1000 * mi->overhead / minstrel_ht_avg_ampdu_len(mi); + + 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_ewma > MINSTREL_FRAC(90, 100)) + return MINSTREL_TRUNC(100000 * ((MINSTREL_FRAC(90, 100) * 1000) + / nsecs)); + else + return MINSTREL_TRUNC(100000 * ((prob_ewma * 1000) / 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 = index / MCS_GROUP_RATES; + cur_idx = index % MCS_GROUP_RATES; + cur_prob = mi->groups[cur_group].rates[cur_idx].prob_ewma; + cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx, cur_prob); + + do { + tmp_group = tp_list[j - 1] / MCS_GROUP_RATES; + tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES; + tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma; + 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 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, cur_tp_avg, cur_group, cur_idx; + int max_gpr_group, max_gpr_idx; + int max_gpr_tp_avg, max_gpr_prob; + + cur_group = index / MCS_GROUP_RATES; + cur_idx = index % MCS_GROUP_RATES; + mg = &mi->groups[index / MCS_GROUP_RATES]; + mrs = &mg->rates[index % MCS_GROUP_RATES]; + + tmp_group = mi->max_prob_rate / MCS_GROUP_RATES; + tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES; + tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma; + 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->max_tp_rate[0] / MCS_GROUP_RATES; + if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) && + (max_tp_group != MINSTREL_CCK_GROUP)) + return; + + max_gpr_group = mg->max_group_prob_rate / MCS_GROUP_RATES; + max_gpr_idx = mg->max_group_prob_rate % MCS_GROUP_RATES; + max_gpr_prob = mi->groups[max_gpr_group].rates[max_gpr_idx].prob_ewma; + + if (mrs->prob_ewma > MINSTREL_FRAC(75, 100)) { + cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx, + mrs->prob_ewma); + if (cur_tp_avg > tmp_tp_avg) + mi->max_prob_rate = 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_ewma > tmp_prob) + mi->max_prob_rate = index; + if (mrs->prob_ewma > 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_cck_tp_rate[MAX_THR_RATES]) +{ + unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp, tmp_prob; + int i; + + tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES; + tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES; + tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma; + tmp_cck_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob); + + tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES; + tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES; + tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma; + tmp_mcs_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob); + + if (tmp_cck_tp_rate && tmp_cck_tp > tmp_mcs_tp) { + for(i = 0; i < MAX_THR_RATES; i++) { + minstrel_ht_sort_best_tp_rates(mi, tmp_cck_tp_rate[i], + tmp_mcs_tp_rate); + } + } + +} + +/* + * Try to increase robustness of max_prob rate by decrease number of + * streams if possible. + */ +static inline void +minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi) +{ + struct minstrel_mcs_group_data *mg; + int tmp_max_streams, group, tmp_idx, tmp_prob; + int tmp_tp = 0; + + tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] / + MCS_GROUP_RATES].streams; + for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { + mg = &mi->groups[group]; + if (!mi->supported[group] || group == MINSTREL_CCK_GROUP) + continue; + + tmp_idx = mg->max_group_prob_rate % MCS_GROUP_RATES; + tmp_prob = mi->groups[group].rates[tmp_idx].prob_ewma; + + 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 inline int +minstrel_get_duration(int index) +{ + const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; + unsigned int duration = group->duration[index % MCS_GROUP_RATES]; + return duration << group->shift; +} + +static bool +minstrel_ht_probe_group(struct minstrel_ht_sta *mi, const struct mcs_group *tp_group, + int tp_idx, const struct mcs_group *group) +{ + if (group->bw < tp_group->bw) + return false; + + if (group->streams == tp_group->streams) + return true; + + if (tp_idx < 4 && group->streams == tp_group->streams - 1) + return true; + + return group->streams == tp_group->streams + 1; +} + +static void +minstrel_ht_find_probe_rates(struct minstrel_ht_sta *mi, u16 *rates, int *n_rates, + bool faster_rate) +{ + const struct mcs_group *group, *tp_group; + int i, g, max_dur; + int tp_idx; + + tp_group = &minstrel_mcs_groups[mi->max_tp_rate[0] / MCS_GROUP_RATES]; + tp_idx = mi->max_tp_rate[0] % MCS_GROUP_RATES; + + max_dur = minstrel_get_duration(mi->max_tp_rate[0]); + if (faster_rate) + max_dur -= max_dur / 16; + + for (g = 0; g < MINSTREL_GROUPS_NB; g++) { + u16 supported = mi->supported[g]; + + if (!supported) + continue; + + group = &minstrel_mcs_groups[g]; + if (!minstrel_ht_probe_group(mi, tp_group, tp_idx, group)) + continue; + + for (i = 0; supported; supported >>= 1, i++) { + int idx; + + if (!(supported & 1)) + continue; + + if ((group->duration[i] << group->shift) > max_dur) + continue; + + idx = g * MCS_GROUP_RATES + i; + if (idx == mi->max_tp_rate[0]) + continue; + + rates[(*n_rates)++] = idx; + break; + } + } +} + +static void +minstrel_ht_rate_sample_switch(struct minstrel_priv *mp, + struct minstrel_ht_sta *mi) +{ + struct minstrel_rate_stats *mrs; + u16 rates[MINSTREL_GROUPS_NB]; + int n_rates = 0; + int probe_rate = 0; + bool faster_rate; + int i; + u8 random; + + /* + * Use rate switching instead of probing packets for devices with + * little control over retry fallback behavior + */ + if (mp->hw->max_rates > 1) + return; + + /* + * If the current EWMA prob is >75%, look for a rate that's 6.25% + * faster than the max tp rate. + * If that fails, look again for a rate that is at least as fast + */ + mrs = minstrel_get_ratestats(mi, mi->max_tp_rate[0]); + faster_rate = mrs->prob_ewma > MINSTREL_FRAC(75, 100); + minstrel_ht_find_probe_rates(mi, rates, &n_rates, faster_rate); + if (!n_rates && faster_rate) + minstrel_ht_find_probe_rates(mi, rates, &n_rates, false); + + /* If no suitable rate was found, try to pick the next one in the group */ + if (!n_rates) { + int g_idx = mi->max_tp_rate[0] / MCS_GROUP_RATES; + u16 supported = mi->supported[g_idx]; + + supported >>= mi->max_tp_rate[0] % MCS_GROUP_RATES; + for (i = 0; supported; supported >>= 1, i++) { + if (!(supported & 1)) + continue; + + probe_rate = mi->max_tp_rate[0] + i; + goto out; + } + + return; + } + + i = 0; + if (n_rates > 1) { + random = prandom_u32(); + i = random % n_rates; + } + probe_rate = rates[i]; + +out: + mi->sample_rate = probe_rate; + mi->sample_mode = MINSTREL_SAMPLE_ACTIVE; +} + +/* + * 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, + bool sample) +{ + 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_cck_tp_rate[MAX_THR_RATES], index; + + mi->sample_mode = MINSTREL_SAMPLE_IDLE; + + if (sample) { + mi->total_packets_cur = mi->total_packets - + mi->total_packets_last; + mi->total_packets_last = mi->total_packets; + } + if (!mp->sample_switch) + sample = false; + if (mi->total_packets_cur < SAMPLE_SWITCH_THR && mp->sample_switch != 1) + sample = false; + + 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, + MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), + EWMA_LEVEL); + else + mi->avg_ampdu_len = 0; + mi->ampdu_len = 0; + mi->ampdu_packets = 0; + } + + mi->sample_slow = 0; + mi->sample_count = 0; + + memset(tmp_mcs_tp_rate, 0, sizeof(tmp_mcs_tp_rate)); + memset(tmp_cck_tp_rate, 0, sizeof(tmp_cck_tp_rate)); + if (mi->supported[MINSTREL_CCK_GROUP]) + for (j = 0; j < ARRAY_SIZE(tmp_cck_tp_rate); j++) + tmp_cck_tp_rate[j] = MINSTREL_CCK_GROUP * MCS_GROUP_RATES; + + if (mi->supported[MINSTREL_VHT_GROUP_0]) + index = MINSTREL_VHT_GROUP_0 * MCS_GROUP_RATES; + else + index = MINSTREL_HT_GROUP_0 * MCS_GROUP_RATES; + + for (j = 0; j < ARRAY_SIZE(tmp_mcs_tp_rate); j++) + tmp_mcs_tp_rate[j] = index; + + /* Find best rate sets within all MCS groups*/ + for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { + + mg = &mi->groups[group]; + if (!mi->supported[group]) + continue; + + mi->sample_count++; + + /* (re)Initialize group rate indexes */ + for(j = 0; j < MAX_THR_RATES; j++) + tmp_group_tp_rate[j] = MCS_GROUP_RATES * group; + + for (i = 0; i < MCS_GROUP_RATES; i++) { + if (!(mi->supported[group] & BIT(i))) + continue; + + index = MCS_GROUP_RATES * group + i; + + mrs = &mg->rates[i]; + mrs->retry_updated = false; + minstrel_calc_rate_stats(mrs); + cur_prob = mrs->prob_ewma; + + if (minstrel_ht_get_tp_avg(mi, group, i, cur_prob) == 0) + continue; + + /* Find max throughput rate set */ + if (group != MINSTREL_CCK_GROUP) { + minstrel_ht_sort_best_tp_rates(mi, index, + tmp_mcs_tp_rate); + } else if (group == MINSTREL_CCK_GROUP) { + minstrel_ht_sort_best_tp_rates(mi, index, + tmp_cck_tp_rate); + } + + /* Find max throughput rate set within a group */ + minstrel_ht_sort_best_tp_rates(mi, index, + tmp_group_tp_rate); + + /* Find max probability rate per group and global */ + minstrel_ht_set_best_prob_rate(mi, index); + } + + memcpy(mg->max_group_tp_rate, tmp_group_tp_rate, + sizeof(mg->max_group_tp_rate)); + } + + /* Assign new rate set per sta */ + minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate); + memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate)); + + /* Try to increase robustness of max_prob_rate*/ + minstrel_ht_prob_rate_reduce_streams(mi); + + /* try to sample all available rates during each interval */ + mi->sample_count *= 8; + + if (sample) + minstrel_ht_rate_sample_switch(mp, mi); + +#ifdef CPTCFG_MAC80211_DEBUGFS + /* use fixed index if set */ + if (mp->fixed_rate_idx != -1) { + for (i = 0; i < 4; i++) + mi->max_tp_rate[i] = mp->fixed_rate_idx; + mi->max_prob_rate = mp->fixed_rate_idx; + mi->sample_mode = MINSTREL_SAMPLE_IDLE; + } +#endif + + /* Reset update timer */ + mi->last_stats_update = jiffies; +} + +static bool +minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate) +{ + if (rate->idx < 0) + return false; + + if (!rate->count) + return false; + + if (rate->flags & IEEE80211_TX_RC_MCS || + rate->flags & IEEE80211_TX_RC_VHT_MCS) + return true; + + return rate->idx == mp->cck_rates[0] || + rate->idx == mp->cck_rates[1] || + rate->idx == mp->cck_rates[2] || + rate->idx == mp->cck_rates[3]; +} + +static void +minstrel_set_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 (!mi->supported[mi->sample_group]) + 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, u16 *idx, bool primary) +{ + int group, orig_group; + + orig_group = group = *idx / MCS_GROUP_RATES; + while (group > 0) { + group--; + + if (!mi->supported[group]) + continue; + + if (minstrel_mcs_groups[group].streams > + minstrel_mcs_groups[orig_group].streams) + continue; + + if (primary) + *idx = mi->groups[group].max_group_tp_rate[0]; + else + *idx = mi->groups[group].max_group_tp_rate[1]; + 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 (skb_get_queue_mapping(skb) == IEEE80211_AC_VO) + return; + + if (unlikely(!ieee80211_is_data_qos(hdr->frame_control))) + return; + + if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE))) + return; + + tid = ieee80211_get_tid(hdr); + if (likely(sta->ampdu_mlme.tid_tx[tid])) + return; + + ieee80211_start_tx_ba_session(pubsta, tid, 0); +} + +static void +minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, + void *priv_sta, struct ieee80211_tx_status *st) +{ + struct ieee80211_tx_info *info = st->info; + struct minstrel_ht_sta_priv *msp = priv_sta; + struct minstrel_ht_sta *mi = &msp->ht; + struct ieee80211_tx_rate *ar = info->status.rates; + struct minstrel_rate_stats *rate, *rate2, *rate_sample = NULL; + struct minstrel_priv *mp = priv; + bool last, update = false; + bool sample_status = false; + int i; + + if (!msp->is_ht) + return mac80211_minstrel.tx_status_ext(priv, sband, + &msp->legacy, st); + + + /* 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) { + int avg_ampdu_len = minstrel_ht_avg_ampdu_len(mi); + + mi->sample_wait = 16 + 2 * avg_ampdu_len; + mi->sample_tries = 1; + mi->sample_count--; + } + + if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) + mi->sample_packets += info->status.ampdu_len; + + if (mi->sample_mode != MINSTREL_SAMPLE_IDLE) + rate_sample = minstrel_get_ratestats(mi, mi->sample_rate); + + last = !minstrel_ht_txstat_valid(mp, &ar[0]); + for (i = 0; !last; i++) { + last = (i == IEEE80211_TX_MAX_RATES - 1) || + !minstrel_ht_txstat_valid(mp, &ar[i + 1]); + + rate = minstrel_ht_get_stats(mp, mi, &ar[i]); + if (rate == rate_sample) + sample_status = true; + + if (last) + rate->success += info->status.ampdu_ack_len; + + rate->attempts += ar[i].count * info->status.ampdu_len; + } + + switch (mi->sample_mode) { + case MINSTREL_SAMPLE_IDLE: + break; + + case MINSTREL_SAMPLE_ACTIVE: + if (!sample_status) + break; + + mi->sample_mode = MINSTREL_SAMPLE_PENDING; + update = true; + break; + + case MINSTREL_SAMPLE_PENDING: + if (sample_status) + break; + + update = true; + minstrel_ht_update_stats(mp, mi, false); + break; + } + + + if (mp->hw->max_rates > 1) { + /* + * 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[0]); + if (rate->attempts > 30 && + MINSTREL_FRAC(rate->success, rate->attempts) < + MINSTREL_FRAC(20, 100)) { + minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true); + update = true; + } + + rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]); + if (rate2->attempts > 30 && + MINSTREL_FRAC(rate2->success, rate2->attempts) < + MINSTREL_FRAC(20, 100)) { + minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false); + update = true; + } + } + + if (time_after(jiffies, mi->last_stats_update + + (mp->update_interval / 2 * HZ) / 1000)) { + update = true; + minstrel_ht_update_stats(mp, mi, true); + } + + if (update) + minstrel_ht_update_rates(mp, mi); +} + +static void +minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, + int index) +{ + struct minstrel_rate_stats *mrs; + 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_ht_avg_ampdu_len(mi); + unsigned int overhead = 0, overhead_rtscts = 0; + + mrs = minstrel_get_ratestats(mi, index); + if (mrs->prob_ewma < MINSTREL_FRAC(1, 10)) { + mrs->retry_count = 1; + mrs->retry_count_rtscts = 1; + return; + } + + mrs->retry_count = 2; + mrs->retry_count_rtscts = 2; + mrs->retry_updated = true; + + tx_time_data = minstrel_get_duration(index) * ampdu_len / 1000; + + /* 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); + + if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) { + overhead = mi->overhead; + overhead_rtscts = mi->overhead_rtscts; + } + + /* Total TX time for data and Contention after first 2 tries */ + tx_time = ctime + 2 * (overhead + tx_time_data); + tx_time_rtscts = ctime + 2 * (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 + overhead + tx_time_data; + tx_time_rtscts += ctime + overhead_rtscts + tx_time_data; + + if (tx_time_rtscts < mp->segment_size) + mrs->retry_count_rtscts++; + } while ((tx_time < mp->segment_size) && + (++mrs->retry_count < mp->max_retry)); +} + + +static void +minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, + struct ieee80211_sta_rates *ratetbl, int offset, int index) +{ + const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; + struct minstrel_rate_stats *mrs; + u8 idx; + u16 flags = group->flags; + + mrs = minstrel_get_ratestats(mi, index); + if (!mrs->retry_updated) + minstrel_calc_retransmit(mp, mi, index); + + if (mrs->prob_ewma < MINSTREL_FRAC(20, 100) || !mrs->retry_count) { + ratetbl->rate[offset].count = 2; + ratetbl->rate[offset].count_rts = 2; + ratetbl->rate[offset].count_cts = 2; + } else { + ratetbl->rate[offset].count = mrs->retry_count; + ratetbl->rate[offset].count_cts = mrs->retry_count; + ratetbl->rate[offset].count_rts = mrs->retry_count_rtscts; + } + + if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) + idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)]; + else if (flags & IEEE80211_TX_RC_VHT_MCS) + idx = ((group->streams - 1) << 4) | + ((index % MCS_GROUP_RATES) & 0xF); + else + idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8; + + /* enable RTS/CTS if needed: + * - if station is in dynamic SMPS (and streams > 1) + * - for fallback rates, to increase chances of getting through + */ + if (offset > 0 || + (mi->sta->smps_mode == IEEE80211_SMPS_DYNAMIC && + group->streams > 1)) { + ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts; + flags |= IEEE80211_TX_RC_USE_RTS_CTS; + } + + ratetbl->rate[offset].idx = idx; + ratetbl->rate[offset].flags = flags; +} + +static inline int +minstrel_ht_get_prob_ewma(struct minstrel_ht_sta *mi, int rate) +{ + int group = rate / MCS_GROUP_RATES; + rate %= MCS_GROUP_RATES; + return mi->groups[group].rates[rate].prob_ewma; +} + +static int +minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta *mi) +{ + int group = mi->max_prob_rate / MCS_GROUP_RATES; + const struct mcs_group *g = &minstrel_mcs_groups[group]; + int rate = mi->max_prob_rate % MCS_GROUP_RATES; + unsigned int duration; + + /* Disable A-MSDU if max_prob_rate is bad */ + if (mi->groups[group].rates[rate].prob_ewma < MINSTREL_FRAC(50, 100)) + return 1; + + duration = g->duration[rate]; + duration <<= g->shift; + + /* If the rate is slower than single-stream MCS1, make A-MSDU limit small */ + if (duration > MCS_DURATION(1, 0, 52)) + return 500; + + /* + * If the rate is slower than single-stream MCS4, limit A-MSDU to usual + * data packet size + */ + if (duration > MCS_DURATION(1, 0, 104)) + return 1600; + + /* + * If the rate is slower than single-stream MCS7, or if the max throughput + * rate success probability is less than 75%, limit A-MSDU to twice the usual + * data packet size + */ + if (duration > MCS_DURATION(1, 0, 260) || + (minstrel_ht_get_prob_ewma(mi, mi->max_tp_rate[0]) < + MINSTREL_FRAC(75, 100))) + return 3200; + + /* + * HT A-MPDU limits maximum MPDU size under BA agreement to 4095 bytes. + * Since aggregation sessions are started/stopped without txq flush, use + * the limit here to avoid the complexity of having to de-aggregate + * packets in the queue. + */ + if (!mi->sta->vht_cap.vht_supported) + return IEEE80211_MAX_MPDU_LEN_HT_BA; + + /* unlimited */ + return 0; +} + +static void +minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) +{ + struct ieee80211_sta_rates *rates; + u16 first_rate = mi->max_tp_rate[0]; + int i = 0; + + if (mi->sample_mode == MINSTREL_SAMPLE_ACTIVE) + first_rate = mi->sample_rate; + + rates = kzalloc(sizeof(*rates), GFP_ATOMIC); + if (!rates) + return; + + /* Start with max_tp_rate[0] */ + minstrel_ht_set_rate(mp, mi, rates, i++, first_rate); + + if (mp->hw->max_rates >= 3) { + /* At least 3 tx rates supported, use max_tp_rate[1] next */ + minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]); + } + + if (mp->hw->max_rates >= 2) { + minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate); + } + + mi->sta->max_rc_amsdu_len = minstrel_ht_get_max_amsdu_len(mi); + rates->rate[i].idx = -1; + rate_control_set_rates(mp->hw, mi->sta, rates); +} + +static int +minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) +{ + struct minstrel_rate_stats *mrs; + struct minstrel_mcs_group_data *mg; + unsigned int sample_dur, sample_group, cur_max_tp_streams; + int tp_rate1, tp_rate2; + int sample_idx = 0; + + if (mp->hw->max_rates == 1 && mp->sample_switch && + (mi->total_packets_cur >= SAMPLE_SWITCH_THR || + mp->sample_switch == 1)) + return -1; + + if (mi->sample_wait > 0) { + mi->sample_wait--; + return -1; + } + + if (!mi->sample_tries) + return -1; + + sample_group = mi->sample_group; + mg = &mi->groups[sample_group]; + sample_idx = sample_table[mg->column][mg->index]; + minstrel_set_next_sample_idx(mi); + + if (!(mi->supported[sample_group] & BIT(sample_idx))) + return -1; + + mrs = &mg->rates[sample_idx]; + sample_idx += sample_group * MCS_GROUP_RATES; + + /* Set tp_rate1, tp_rate2 to the highest / second highest max_tp_rate */ + if (minstrel_get_duration(mi->max_tp_rate[0]) > + minstrel_get_duration(mi->max_tp_rate[1])) { + tp_rate1 = mi->max_tp_rate[1]; + tp_rate2 = mi->max_tp_rate[0]; + } else { + tp_rate1 = mi->max_tp_rate[0]; + tp_rate2 = mi->max_tp_rate[1]; + } + + /* + * Sampling might add some overhead (RTS, no aggregation) + * to the frame. Hence, don't use sampling for the highest currently + * used highest throughput or probability rate. + */ + if (sample_idx == mi->max_tp_rate[0] || sample_idx == mi->max_prob_rate) + return -1; + + /* + * Do not sample if the probability is already higher than 95%, + * or if the rate is 3 times slower than the current max probability + * rate, to avoid wasting airtime. + */ + sample_dur = minstrel_get_duration(sample_idx); + if (mrs->prob_ewma > MINSTREL_FRAC(95, 100) || + minstrel_get_duration(mi->max_prob_rate) * 3 < sample_dur) + return -1; + + + /* + * For devices with no configurable multi-rate retry, skip sampling + * below the per-group max throughput rate, and only use one sampling + * attempt per rate + */ + if (mp->hw->max_rates == 1 && + (minstrel_get_duration(mg->max_group_tp_rate[0]) < sample_dur || + mrs->attempts)) + return -1; + + /* Skip already sampled slow rates */ + if (sample_dur >= minstrel_get_duration(tp_rate1) && mrs->attempts) + return -1; + + /* + * Make sure that lower rates get sampled only occasionally, + * if the link is working perfectly. + */ + + cur_max_tp_streams = minstrel_mcs_groups[tp_rate1 / + MCS_GROUP_RATES].streams; + if (sample_dur >= minstrel_get_duration(tp_rate2) && + (cur_max_tp_streams - 1 < + minstrel_mcs_groups[sample_group].streams || + sample_dur >= minstrel_get_duration(mi->max_prob_rate))) { + if (mrs->sample_skipped < 20) + return -1; + + if (mi->sample_slow++ > 2) + return -1; + } + mi->sample_tries--; + + return sample_idx; +} + +static void +minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, + struct ieee80211_tx_rate_control *txrc) +{ + const struct mcs_group *sample_group; + struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); + struct ieee80211_tx_rate *rate = &info->status.rates[0]; + struct minstrel_ht_sta_priv *msp = priv_sta; + struct minstrel_ht_sta *mi = &msp->ht; + struct minstrel_priv *mp = priv; + int sample_idx; + + if (!msp->is_ht) + return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc); + + if (!(info->flags & IEEE80211_TX_CTL_AMPDU) && + mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) + minstrel_aggr_check(sta, txrc->skb); + + info->flags |= mi->tx_flags; + +#ifdef CPTCFG_MAC80211_DEBUGFS + if (mp->fixed_rate_idx != -1) + return; +#endif + + /* Don't use EAPOL frames for sampling on non-mrr hw */ + if (mp->hw->max_rates == 1 && + (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO)) + sample_idx = -1; + else + sample_idx = minstrel_get_sample_rate(mp, mi); + + mi->total_packets++; + + /* wraparound */ + if (mi->total_packets == ~0) { + mi->total_packets = 0; + mi->sample_packets = 0; + } + + if (sample_idx < 0) + return; + + sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES]; + sample_idx %= MCS_GROUP_RATES; + + if (sample_group == &minstrel_mcs_groups[MINSTREL_CCK_GROUP] && + (sample_idx >= 4) != txrc->short_preamble) + return; + + info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; + rate->count = 1; + + if (sample_group == &minstrel_mcs_groups[MINSTREL_CCK_GROUP]) { + int idx = sample_idx % ARRAY_SIZE(mp->cck_rates); + rate->idx = mp->cck_rates[idx]; + } else if (sample_group->flags & IEEE80211_TX_RC_VHT_MCS) { + ieee80211_rate_set_vht(rate, sample_idx % MCS_GROUP_RATES, + sample_group->streams); + } else { + rate->idx = sample_idx + (sample_group->streams - 1) * 8; + } + + rate->flags = sample_group->flags; +} + +static void +minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, + struct ieee80211_supported_band *sband, + struct ieee80211_sta *sta) +{ + int i; + + if (sband->band != NL80211_BAND_2GHZ) + return; + + if (!ieee80211_hw_check(mp->hw, SUPPORTS_HT_CCK_RATES)) + return; + + mi->cck_supported = 0; + mi->cck_supported_short = 0; + for (i = 0; i < 4; i++) { + if (!rate_supported(sta, sband->band, mp->cck_rates[i])) + continue; + + mi->cck_supported |= BIT(i); + if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE) + mi->cck_supported_short |= BIT(i); + } + + mi->supported[MINSTREL_CCK_GROUP] = mi->cck_supported; +} + +static void +minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, + struct cfg80211_chan_def *chandef, + 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; + u16 ht_cap = sta->ht_cap.cap; + struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap; + int use_vht; + int n_supported = 0; + int ack_dur; + int stbc; + int i; + bool ldpc; + + /* 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_GROUPS_NB); + + if (vht_cap->vht_supported) + use_vht = vht_cap->vht_mcs.tx_mcs_map != cpu_to_le16(~0); + else + use_vht = 0; + + msp->is_ht = true; + memset(mi, 0, sizeof(*mi)); + + mi->sta = sta; + mi->last_stats_update = jiffies; + + ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0); + mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0); + mi->overhead += 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; + + if (!use_vht) { + stbc = (ht_cap & IEEE80211_HT_CAP_RX_STBC) >> + IEEE80211_HT_CAP_RX_STBC_SHIFT; + + ldpc = ht_cap & IEEE80211_HT_CAP_LDPC_CODING; + } else { + stbc = (vht_cap->cap & IEEE80211_VHT_CAP_RXSTBC_MASK) >> + IEEE80211_VHT_CAP_RXSTBC_SHIFT; + + ldpc = vht_cap->cap & IEEE80211_VHT_CAP_RXLDPC; + } + + mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT; + if (ldpc) + mi->tx_flags |= IEEE80211_TX_CTL_LDPC; + + for (i = 0; i < ARRAY_SIZE(mi->groups); i++) { + u32 gflags = minstrel_mcs_groups[i].flags; + int bw, nss; + + mi->supported[i] = 0; + if (i == MINSTREL_CCK_GROUP) { + minstrel_ht_update_cck(mp, mi, sband, sta); + continue; + } + + if (gflags & IEEE80211_TX_RC_SHORT_GI) { + if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH) { + if (!(ht_cap & IEEE80211_HT_CAP_SGI_40)) + continue; + } else { + if (!(ht_cap & IEEE80211_HT_CAP_SGI_20)) + continue; + } + } + + if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH && + sta->bandwidth < IEEE80211_STA_RX_BW_40) + continue; + + nss = minstrel_mcs_groups[i].streams; + + /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */ + if (sta->smps_mode == IEEE80211_SMPS_STATIC && nss > 1) + continue; + + /* HT rate */ + if (gflags & IEEE80211_TX_RC_MCS) { + if (use_vht && minstrel_vht_only) + continue; + + mi->supported[i] = mcs->rx_mask[nss - 1]; + if (mi->supported[i]) + n_supported++; + continue; + } + + /* VHT rate */ + if (!vht_cap->vht_supported || + WARN_ON(!(gflags & IEEE80211_TX_RC_VHT_MCS)) || + WARN_ON(gflags & IEEE80211_TX_RC_160_MHZ_WIDTH)) + continue; + + if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH) { + if (sta->bandwidth < IEEE80211_STA_RX_BW_80 || + ((gflags & IEEE80211_TX_RC_SHORT_GI) && + !(vht_cap->cap & IEEE80211_VHT_CAP_SHORT_GI_80))) { + continue; + } + } + + if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH) + bw = BW_40; + else if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH) + bw = BW_80; + else + bw = BW_20; + + mi->supported[i] = minstrel_get_valid_vht_rates(bw, nss, + vht_cap->vht_mcs.tx_mcs_map); + + if (mi->supported[i]) + n_supported++; + } + + if (!n_supported) + goto use_legacy; + + mi->supported[MINSTREL_CCK_GROUP] |= mi->cck_supported_short << 4; + + /* create an initial rate table with the lowest supported rates */ + minstrel_ht_update_stats(mp, mi, true); + minstrel_ht_update_rates(mp, mi); + + 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, chandef, sta, + &msp->legacy); +} + +static void +minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband, + struct cfg80211_chan_def *chandef, + struct ieee80211_sta *sta, void *priv_sta) +{ + minstrel_ht_update_caps(priv, sband, chandef, sta, priv_sta); +} + +static void +minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband, + struct cfg80211_chan_def *chandef, + struct ieee80211_sta *sta, void *priv_sta, + u32 changed) +{ + minstrel_ht_update_caps(priv, sband, chandef, 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 < NUM_NL80211_BANDS; i++) { + sband = hw->wiphy->bands[i]; + if (sband && sband->n_bitrates > max_rates) + max_rates = sband->n_bitrates; + } + + msp = kzalloc(sizeof(*msp), gfp); + if (!msp) + return NULL; + + msp->ratelist = kcalloc(max_rates, sizeof(struct minstrel_rate), gfp); + if (!msp->ratelist) + goto error; + + msp->sample_table = kmalloc_array(max_rates, SAMPLE_COLUMNS, 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_init_cck_rates(struct minstrel_priv *mp) +{ + static const int bitrates[4] = { 10, 20, 55, 110 }; + struct ieee80211_supported_band *sband; + u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef); + int i, j; + + sband = mp->hw->wiphy->bands[NL80211_BAND_2GHZ]; + if (!sband) + return; + + for (i = 0; i < sband->n_bitrates; i++) { + struct ieee80211_rate *rate = &sband->bitrates[i]; + + if (rate->flags & IEEE80211_RATE_ERP_G) + continue; + + if ((rate_flags & sband->bitrates[i].flags) != rate_flags) + continue; + + for (j = 0; j < ARRAY_SIZE(bitrates); j++) { + if (rate->bitrate != bitrates[j]) + continue; + + mp->cck_rates[j] = i; + break; + } + } +} + +static void * +minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) +{ + struct minstrel_priv *mp; + + mp = kzalloc(sizeof(struct minstrel_priv), GFP_ATOMIC); + if (!mp) + return NULL; + + mp->sample_switch = -1; + + /* contention window settings + * Just an approximation. Using the per-queue values would complicate + * the calculations and is probably unnecessary */ + mp->cw_min = 15; + mp->cw_max = 1023; + + /* number of packets (in %) to use for sampling other rates + * sample less often for non-mrr packets, because the overhead + * is much higher than with mrr */ + mp->lookaround_rate = 5; + mp->lookaround_rate_mrr = 10; + + /* maximum time that the hw is allowed to stay in one MRR segment */ + mp->segment_size = 6000; + + if (hw->max_rate_tries > 0) + mp->max_retry = hw->max_rate_tries; + else + /* safe default, does not necessarily have to match hw properties */ + mp->max_retry = 7; + + if (hw->max_rates >= 4) + mp->has_mrr = true; + + mp->hw = hw; + mp->update_interval = 100; + +#ifdef CPTCFG_MAC80211_DEBUGFS + mp->fixed_rate_idx = (u32) -1; + debugfs_create_u32("fixed_rate_idx", S_IRUGO | S_IWUGO, debugfsdir, + &mp->fixed_rate_idx); + debugfs_create_u32("sample_switch", S_IRUGO | S_IWUSR, debugfsdir, + &mp->sample_switch); +#endif + + minstrel_ht_init_cck_rates(mp); + + return mp; +} + +static void +minstrel_ht_free(void *priv) +{ + kfree(priv); +} + +static u32 minstrel_ht_get_expected_throughput(void *priv_sta) +{ + struct minstrel_ht_sta_priv *msp = priv_sta; + struct minstrel_ht_sta *mi = &msp->ht; + int i, j, prob, tp_avg; + + if (!msp->is_ht) + return mac80211_minstrel.get_expected_throughput(priv_sta); + + i = mi->max_tp_rate[0] / MCS_GROUP_RATES; + j = mi->max_tp_rate[0] % MCS_GROUP_RATES; + prob = mi->groups[i].rates[j].prob_ewma; + + /* convert tp_avg from pkt per second in kbps */ + tp_avg = minstrel_ht_get_tp_avg(mi, i, j, prob) * 10; + tp_avg = tp_avg * AVG_PKT_SIZE * 8 / 1024; + + return tp_avg; +} + +static const struct rate_control_ops mac80211_minstrel_ht = { + .name = "minstrel_ht", + .tx_status_ext = 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 CPTCFG_MAC80211_DEBUGFS + .add_sta_debugfs = minstrel_ht_add_sta_debugfs, +#endif + .get_expected_throughput = minstrel_ht_get_expected_throughput, +}; + + +static void __init 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++) { + prandom_bytes(rnd, sizeof(rnd)); + for (i = 0; i < MCS_GROUP_RATES; i++) { + 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_init(void) +{ + init_sample_table(); + return ieee80211_rate_control_register(&mac80211_minstrel_ht); +} + +void +rc80211_minstrel_exit(void) +{ + ieee80211_rate_control_unregister(&mac80211_minstrel_ht); +} |