diff options
Diffstat (limited to 'net/mac80211/rc80211_minstrel_ht.c')
| -rw-r--r-- | net/mac80211/rc80211_minstrel_ht.c | 911 |
1 files changed, 911 insertions, 0 deletions
diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c new file mode 100644 index 00000000..16e0b277 --- /dev/null +++ b/net/mac80211/rc80211_minstrel_ht.c @@ -0,0 +1,911 @@ +/* + * 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, + enum nl80211_channel_type oper_chan_type) +{ + 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; + + if (oper_chan_type != NL80211_CHAN_HT40MINUS && + oper_chan_type != NL80211_CHAN_HT40PLUS) + sta_cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40; + + 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) +{ + struct minstrel_priv *mp = priv; + + minstrel_ht_update_caps(priv, sband, sta, priv_sta, mp->hw->conf.channel_type); +} + +static void +minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband, + struct ieee80211_sta *sta, void *priv_sta, + u32 changed, enum nl80211_channel_type oper_chan_type) +{ + minstrel_ht_update_caps(priv, sband, sta, priv_sta, oper_chan_type); +} + +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); +} |