net/mac80211/rc80211_minstrel.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
   4  */
   5
   6 #ifndef __RC_MINSTREL_H
   7 #define __RC_MINSTREL_H
   8
   9 #define EWMA_LEVEL      96      /* ewma weighting factor [/EWMA_DIV] */
  10 #define EWMA_DIV        128
  11 #define SAMPLE_COLUMNS  10      /* number of columns in sample table */
  12
  13 /* scaled fraction values */
  14 #define MINSTREL_SCALE  12
  15 #define MINSTREL_FRAC(val, div) (((val) << MINSTREL_SCALE) / div)
  16 #define MINSTREL_TRUNC(val) ((val) >> MINSTREL_SCALE)
  17
  18 /* number of highest throughput rates to consider*/
  19 #define MAX_THR_RATES 4
  20
  21 /*
  22  * Coefficients for moving average with noise filter (period=16),
  23  * scaled by 10 bits
  24  *
  25  * a1 = exp(-pi * sqrt(2) / period)
  26  * coeff2 = 2 * a1 * cos(sqrt(2) * 2 * pi / period)
  27  * coeff3 = -sqr(a1)
  28  * coeff1 = 1 - coeff2 - coeff3
  29  */
  30 #define MINSTREL_AVG_COEFF1             (MINSTREL_FRAC(1, 1) - \
  31                                          MINSTREL_AVG_COEFF2 - \
  32                                          MINSTREL_AVG_COEFF3)
  33 #define MINSTREL_AVG_COEFF2             0x00001499
  34 #define MINSTREL_AVG_COEFF3             -0x0000092e
  35
  36 /*
  37  * Perform EWMA (Exponentially Weighted Moving Average) calculation
  38  */
  39 static inline int
  40 minstrel_ewma(int old, int new, int weight)
  41 {
  42         int diff, incr;
  43
  44         diff = new - old;
  45         incr = (EWMA_DIV - weight) * diff / EWMA_DIV;
  46
  47         return old + incr;
  48 }
  49
  50 static inline int minstrel_filter_avg_add(u16 *prev_1, u16 *prev_2, s32 in)
  51 {
  52         s32 out_1 = *prev_1;
  53         s32 out_2 = *prev_2;
  54         s32 val;
  55
  56         if (!in)
  57                 in += 1;
  58
  59         if (!out_1) {
  60                 val = out_1 = in;
  61                 goto out;
  62         }
  63
  64         val = MINSTREL_AVG_COEFF1 * in;
  65         val += MINSTREL_AVG_COEFF2 * out_1;
  66         val += MINSTREL_AVG_COEFF3 * out_2;
  67         val >>= MINSTREL_SCALE;
  68
  69         if (val > 1 << MINSTREL_SCALE)
  70                 val = 1 << MINSTREL_SCALE;
  71         if (val < 0)
  72                 val = 1;
  73
  74 out:
  75         *prev_2 = out_1;
  76         *prev_1 = val;
  77
  78         return val;
  79 }
  80
  81 struct minstrel_rate_stats {
  82         /* current / last sampling period attempts/success counters */
  83         u16 attempts, last_attempts;
  84         u16 success, last_success;
  85
  86         /* total attempts/success counters */
  87         u32 att_hist, succ_hist;
  88
  89         /* prob_avg - moving average of prob */
  90         u16 prob_avg;
  91         u16 prob_avg_1;
  92
  93         /* maximum retry counts */
  94         u8 retry_count;
  95         u8 retry_count_rtscts;
  96
  97         u8 sample_skipped;
  98         bool retry_updated;
  99 };
 100
 101 struct minstrel_rate {
 102         int bitrate;
 103
 104         s8 rix;
 105         u8 retry_count_cts;
 106         u8 adjusted_retry_count;
 107
 108         unsigned int perfect_tx_time;
 109         unsigned int ack_time;
 110
 111         int sample_limit;
 112
 113         struct minstrel_rate_stats stats;
 114 };
 115
 116 struct minstrel_sta_info {
 117         struct ieee80211_sta *sta;
 118
 119         unsigned long last_stats_update;
 120         unsigned int sp_ack_dur;
 121         unsigned int rate_avg;
 122
 123         unsigned int lowest_rix;
 124
 125         u8 max_tp_rate[MAX_THR_RATES];
 126         u8 max_prob_rate;
 127         unsigned int total_packets;
 128         unsigned int sample_packets;
 129
 130         unsigned int sample_row;
 131         unsigned int sample_column;
 132
 133         int n_rates;
 134         struct minstrel_rate *r;
 135         bool prev_sample;
 136
 137         /* sampling table */
 138         u8 *sample_table;
 139 };
 140
 141 struct minstrel_priv {
 142         struct ieee80211_hw *hw;
 143         bool has_mrr;
 144         bool new_avg;
 145         u32 sample_switch;
 146         unsigned int cw_min;
 147         unsigned int cw_max;
 148         unsigned int max_retry;
 149         unsigned int segment_size;
 150         unsigned int update_interval;
 151         unsigned int lookaround_rate;
 152         unsigned int lookaround_rate_mrr;
 153
 154         u8 cck_rates[4];
 155
 156 #ifdef CONFIG_MAC80211_DEBUGFS
 157         /*
 158          * enable fixed rate processing per RC
 159          *   - write static index to debugfs:ieee80211/phyX/rc/fixed_rate_idx
 160          *   - write -1 to enable RC processing again
 161          *   - setting will be applied on next update
 162          */
 163         u32 fixed_rate_idx;
 164 #endif
 165 };
 166
 167 struct minstrel_debugfs_info {
 168         size_t len;
 169         char buf[];
 170 };
 171
 172 extern const struct rate_control_ops mac80211_minstrel;
 173 void minstrel_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir);
 174
 175 /* Recalculate success probabilities and counters for a given rate using EWMA */
 176 void minstrel_calc_rate_stats(struct minstrel_priv *mp,
 177                               struct minstrel_rate_stats *mrs);
 178 int minstrel_get_tp_avg(struct minstrel_rate *mr, int prob_avg);
 179
 180 /* debugfs */
 181 int minstrel_stats_open(struct inode *inode, struct file *file);
 182 int minstrel_stats_csv_open(struct inode *inode, struct file *file);
 183
 184 #endif