/* * 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))) /* MCS rate information for an MCS group */ #define MCS_GROUP(_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. */ 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) { int streams = (rate->idx / MCS_GROUP_RATES) + 1; u32 flags = IEEE80211_TX_RC_SHORT_GI | IEEE80211_TX_RC_40_MHZ_WIDTH; int i; for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) { if (minstrel_mcs_groups[i].streams != streams) continue; if (minstrel_mcs_groups[i].flags != (rate->flags & flags)) continue; return i; } WARN_ON(1); return 0; } 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_priv *mp, 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_priv *mp, 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(mp, mr); minstrel_ht_calc_tp(mp, 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 availble 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_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->count) return false; if (rate->idx < 0) 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 minstrel_priv *mp, 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; ieee80211_start_tx_ba_session(pubsta, tid); } 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 = 4 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len); mi->sample_tries = 3; mi->sample_count--; } if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) { mi->sample_packets += info->status.ampdu_len; minstrel_next_sample_idx(mi); } 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); minstrel_aggr_check(mp, 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 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; tx_time = 2 * (t_slot + mi->overhead + tx_time_data); tx_time_rtscts = 2 * (t_slot + mi->overhead_rtscts + tx_time_data); do { cw = (cw << 1) | 1; cw = min(cw, mp->cw_max); tx_time += cw + t_slot + mi->overhead; tx_time_rtscts += cw + t_slot + mi->overhead_rtscts; 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, struct ieee80211_tx_rate_control *txrc, 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 (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 (txrc->short_preamble) rate->flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE; if (txrc->rts || 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; /* * 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))) goto next; /* * 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 < 10) goto next; if (mi->sample_slow++ > 2) goto next; } return sample_idx; next: minstrel_next_sample_idx(mi); return -1; } 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; 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; sample_idx = minstrel_get_sample_rate(mp, mi); if (sample_idx >= 0) { minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx, txrc, true, false); minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate, txrc, false, true); info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; } else { minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate, txrc, false, false); minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2, txrc, false, true); } minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, txrc, false, true); ar[3].count = 0; ar[3].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 ack_dur; int stbc; int i; /* fall back to the old minstrel for legacy stations */ if (!sta->ht_cap.ht_supported) { 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); } 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; 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; mi->groups[i].supported = mcs->rx_mask[minstrel_mcs_groups[i].streams - 1]; } } 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); }