/* * Copyright (C) 2010-2013 Felix Fietkau * * 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 #include #include #include #include #include #include #include "rate.h" #include "rc80211_minstrel.h" #include "rc80211_minstrel_ht.h" #define AVG_PKT_SIZE 1200 /* 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 (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))) #define BW_20 0 #define BW_40 1 /* * 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 /* MCS rate information for an MCS group */ #define MCS_GROUP(_streams, _sgi, _ht40) \ [GROUP_IDX(_streams, _sgi, _ht40)] = { \ .streams = _streams, \ .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), \ 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) \ } \ } #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) \ CCK_ACK_DURATION(10, _short), \ CCK_ACK_DURATION(20, _short), \ CCK_ACK_DURATION(55, _short), \ CCK_ACK_DURATION(110, _short) #define CCK_GROUP \ [MINSTREL_CCK_GROUP] = { \ .streams = 0, \ .flags = 0, \ .duration = { \ CCK_DURATION_LIST(false), \ CCK_DURATION_LIST(true) \ } \ } /* * 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), #if MINSTREL_MAX_STREAMS >= 3 MCS_GROUP(3, 0, BW_20), #endif MCS_GROUP(1, 1, BW_20), MCS_GROUP(2, 1, BW_20), #if MINSTREL_MAX_STREAMS >= 3 MCS_GROUP(3, 1, BW_20), #endif MCS_GROUP(1, 0, BW_40), MCS_GROUP(2, 0, BW_40), #if MINSTREL_MAX_STREAMS >= 3 MCS_GROUP(3, 0, BW_40), #endif MCS_GROUP(1, 1, BW_40), MCS_GROUP(2, 1, BW_40), #if MINSTREL_MAX_STREAMS >= 3 MCS_GROUP(3, 1, BW_40), #endif CCK_GROUP }; 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); /* * 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 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 { 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->groups[group].supported & BIT(idx))) 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]; } /* * 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 nsecs = 0; unsigned int tp; unsigned int prob; mr = &mi->groups[group].rates[rate]; prob = mr->probability; if (prob < MINSTREL_FRAC(1, 10)) { mr->cur_tp = 0; return; } /* * For the throughput calculation, limit the probability value to 90% to * account for collision related packet error rate fluctuation */ if (prob > MINSTREL_FRAC(9, 10)) prob = MINSTREL_FRAC(9, 10); if (group != MINSTREL_CCK_GROUP) nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len); nsecs += minstrel_mcs_groups[group].duration[rate]; /* prob is scaled - see MINSTREL_FRAC above */ tp = 1000000 * ((prob * 1000) / nsecs); mr->cur_tp = MINSTREL_TRUNC(tp); } /* * 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_thr, cur_prob; int tmp_group, tmp_idx, tmp_thr, tmp_prob; int j = MAX_THR_RATES; cur_group = index / MCS_GROUP_RATES; cur_idx = index % MCS_GROUP_RATES; cur_thr = mi->groups[cur_group].rates[cur_idx].cur_tp; cur_prob = mi->groups[cur_group].rates[cur_idx].probability; tmp_group = tp_list[j - 1] / MCS_GROUP_RATES; tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES; tmp_thr = mi->groups[tmp_group].rates[tmp_idx].cur_tp; tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability; while (j > 0 && (cur_thr > tmp_thr || (cur_thr == tmp_thr && cur_prob > tmp_prob))) { j--; tmp_group = tp_list[j - 1] / MCS_GROUP_RATES; tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES; tmp_thr = mi->groups[tmp_group].rates[tmp_idx].cur_tp; tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability; } 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 *mr; int tmp_group, tmp_idx, tmp_tp, tmp_prob, max_tp_group; mg = &mi->groups[index / MCS_GROUP_RATES]; mr = &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_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp; tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability; /* 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; if (mr->probability > MINSTREL_FRAC(75, 100)) { if (mr->cur_tp > tmp_tp) mi->max_prob_rate = index; if (mr->cur_tp > mg->rates[mg->max_group_prob_rate].cur_tp) mg->max_group_prob_rate = index; } else { if (mr->probability > tmp_prob) mi->max_prob_rate = index; if (mr->probability > mg->rates[mg->max_group_prob_rate].probability) 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; int i; tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES; tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES; tmp_cck_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp; tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES; tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES; tmp_mcs_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp; if (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; struct minstrel_rate_stats *mr; int tmp_max_streams, group; 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 (!mg->supported || group == MINSTREL_CCK_GROUP) continue; mr = minstrel_get_ratestats(mi, mg->max_group_prob_rate); if (tmp_tp < mr->cur_tp && (minstrel_mcs_groups[group].streams < tmp_max_streams)) { mi->max_prob_rate = mg->max_group_prob_rate; tmp_tp = mr->cur_tp; } } } /* * Update rate statistics and select new primary rates * * Rules for rate selection: * - max_prob_rate must use only one stream, as a tradeoff between delivery * probability and throughput during strong fluctuations * - as long as the max prob rate has a probability of more than 75%, pick * higher throughput rates, even if the probablity is a bit lower */ static void minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) { struct minstrel_mcs_group_data *mg; struct minstrel_rate_stats *mr; int group, i, j; u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES]; u16 tmp_cck_tp_rate[MAX_THR_RATES], 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; /* Initialize global rate indexes */ for(j = 0; j < MAX_THR_RATES; j++){ tmp_mcs_tp_rate[j] = 0; tmp_cck_tp_rate[j] = 0; } /* Find best rate sets within all MCS groups*/ for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) { mg = &mi->groups[group]; if (!mg->supported) continue; mi->sample_count++; /* (re)Initialize group rate indexes */ for(j = 0; j < MAX_THR_RATES; j++) tmp_group_tp_rate[j] = group; for (i = 0; i < MCS_GROUP_RATES; i++) { if (!(mg->supported & BIT(i))) continue; index = MCS_GROUP_RATES * group + i; mr = &mg->rates[i]; mr->retry_updated = false; minstrel_calc_rate_ewma(mr); minstrel_ht_calc_tp(mi, group, i); if (!mr->cur_tp) 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; #ifdef CONFIG_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; } #endif /* Reset update timer */ mi->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) 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_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, u16 *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_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 (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, update = false; int i; 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 = 1; mi->sample_count--; } if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) mi->sample_packets += info->status.ampdu_len; 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 (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[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->stats_update + (mp->update_interval / 2 * HZ) / 1000)) { update = true; minstrel_ht_update_stats(mp, mi); if (!(info->flags & IEEE80211_TX_CTL_AMPDU) && mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) minstrel_aggr_check(sta, skb); } 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 *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); unsigned int overhead = 0, overhead_rtscts = 0; 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 / 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) 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_sta_rates *ratetbl, int offset, int index) { const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES]; struct minstrel_rate_stats *mr; u8 idx; u16 flags = group->flags; mr = minstrel_get_ratestats(mi, index); if (!mr->retry_updated) minstrel_calc_retransmit(mp, mi, index); if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) { ratetbl->rate[offset].count = 2; ratetbl->rate[offset].count_rts = 2; ratetbl->rate[offset].count_cts = 2; } else { ratetbl->rate[offset].count = mr->retry_count; ratetbl->rate[offset].count_cts = mr->retry_count; ratetbl->rate[offset].count_rts = mr->retry_count_rtscts; } if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)]; else idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8; if (offset > 0) { 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 void minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) { struct ieee80211_sta_rates *rates; int i = 0; rates = kzalloc(sizeof(*rates), GFP_ATOMIC); if (!rates) return; /* Start with max_tp_rate[0] */ minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]); 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) { /* * At least 2 tx rates supported, use max_prob_rate next */ minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate); } rates->rate[i].idx = -1; rate_control_set_rates(mp->hw, mi->sta, 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; unsigned int sample_dur, sample_group, cur_max_tp_streams; int sample_idx = 0; 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_next_sample_idx(mi); if (!(mg->supported & BIT(sample_idx))) return -1; mr = &mg->rates[sample_idx]; sample_idx += sample_group * MCS_GROUP_RATES; /* * Sampling might add some overhead (RTS, no aggregation) * to the frame. Hence, don't use sampling for the currently * used rates. */ if (sample_idx == mi->max_tp_rate[0] || sample_idx == mi->max_tp_rate[1] || sample_idx == mi->max_prob_rate) return -1; /* * Do not sample if the probability is already higher than 95% * to avoid wasting airtime. */ if (mr->probability > MINSTREL_FRAC(95, 100)) return -1; /* * Make sure that lower rates get sampled only occasionally, * if the link is working perfectly. */ cur_max_tp_streams = minstrel_mcs_groups[mi->max_tp_rate[0] / MCS_GROUP_RATES].streams; sample_dur = minstrel_get_duration(sample_idx); if (sample_dur >= minstrel_get_duration(mi->max_tp_rate[1]) && (cur_max_tp_streams - 1 < minstrel_mcs_groups[sample_group].streams || sample_dur >= minstrel_get_duration(mi->max_prob_rate))) { if (mr->sample_skipped < 20) return -1; if (mi->sample_slow++ > 2) return -1; } mi->sample_tries--; return sample_idx; } static void minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, bool val) { u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported; if (!supported || !mi->cck_supported_short) return; if (supported & (mi->cck_supported_short << (val * 4))) return; supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4); mi->groups[MINSTREL_CCK_GROUP].supported = supported; } 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 (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; minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble); #ifdef CONFIG_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]; info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; rate->count = 1; if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) { int idx = sample_idx % ARRAY_SIZE(mp->cck_rates); rate->idx = mp->cck_rates[idx]; } else { rate->idx = sample_idx % MCS_GROUP_RATES + (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 != IEEE80211_BAND_2GHZ) return; if (!(mp->hw->flags & IEEE80211_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->groups[MINSTREL_CCK_GROUP].supported = 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 sta_cap = sta->ht_cap.cap; int n_supported = 0; int ack_dur; int stbc; int i; /* 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); msp->is_ht = true; memset(mi, 0, sizeof(*mi)); mi->sta = sta; mi->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; 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; for (i = 0; i < ARRAY_SIZE(mi->groups); i++) { u32 gflags = minstrel_mcs_groups[i].flags; mi->groups[i].supported = 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 (!(sta_cap & IEEE80211_HT_CAP_SGI_40)) continue; } else { if (!(sta_cap & IEEE80211_HT_CAP_SGI_20)) continue; } } if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH && sta->bandwidth < IEEE80211_STA_RX_BW_40) continue; /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */ if (sta->smps_mode == IEEE80211_SMPS_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; /* create an initial rate table with the lowest supported rates */ minstrel_ht_update_stats(mp, mi); 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 < IEEE80211_NUM_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 = 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 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; 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; /* convert cur_tp from pkt per second in kbps */ return mi->groups[i].rates[j].cur_tp * AVG_PKT_SIZE * 8 / 1024; } static const 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 .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_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); }