1 /*
2 * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9 #ifndef __RC_MINSTREL_H
10 #define __RC_MINSTREL_H
11
12 #define EWMA_LEVEL 96 /* ewma weighting factor [/EWMA_DIV] */
13 #define EWMA_DIV 128
14 #define SAMPLE_COLUMNS 10 /* number of columns in sample table */
15
16 /* scaled fraction values */
17 #define MINSTREL_SCALE 16
18 #define MINSTREL_FRAC(val, div) (((val) << MINSTREL_SCALE) / div)
19 #define MINSTREL_TRUNC(val) ((val) >> MINSTREL_SCALE)
20
21 /* number of highest throughput rates to consider*/
22 #define MAX_THR_RATES 4
23
24 /*
25 * Perform EWMA (Exponentially Weighted Moving Average) calculation
26 */
27 static inline int
minstrel_ewma(int old,int new,int weight)28 minstrel_ewma(int old, int new, int weight)
29 {
30 int diff, incr;
31
32 diff = new - old;
33 incr = (EWMA_DIV - weight) * diff / EWMA_DIV;
34
35 return old + incr;
36 }
37
38 /*
39 * Perform EWMSD (Exponentially Weighted Moving Standard Deviation) calculation
40 */
41 static inline int
minstrel_ewmsd(int old_ewmsd,int cur_prob,int prob_ewma,int weight)42 minstrel_ewmsd(int old_ewmsd, int cur_prob, int prob_ewma, int weight)
43 {
44 int diff, incr, tmp_var;
45
46 /* calculate exponential weighted moving variance */
47 diff = MINSTREL_TRUNC((cur_prob - prob_ewma) * 1000000);
48 incr = (EWMA_DIV - weight) * diff / EWMA_DIV;
49 tmp_var = old_ewmsd * old_ewmsd;
50 tmp_var = weight * (tmp_var + diff * incr / 1000000) / EWMA_DIV;
51
52 /* return standard deviation */
53 return (u16) int_sqrt(tmp_var);
54 }
55
56 struct minstrel_rate_stats {
57 /* current / last sampling period attempts/success counters */
58 u16 attempts, last_attempts;
59 u16 success, last_success;
60
61 /* total attempts/success counters */
62 u64 att_hist, succ_hist;
63
64 /* statistis of packet delivery probability
65 * cur_prob - current prob within last update intervall
66 * prob_ewma - exponential weighted moving average of prob
67 * prob_ewmsd - exp. weighted moving standard deviation of prob */
68 unsigned int cur_prob;
69 unsigned int prob_ewma;
70 u16 prob_ewmsd;
71
72 /* maximum retry counts */
73 u8 retry_count;
74 u8 retry_count_rtscts;
75
76 u8 sample_skipped;
77 bool retry_updated;
78 };
79
80 struct minstrel_rate {
81 int bitrate;
82
83 s8 rix;
84 u8 retry_count_cts;
85 u8 adjusted_retry_count;
86
87 unsigned int perfect_tx_time;
88 unsigned int ack_time;
89
90 int sample_limit;
91
92 struct minstrel_rate_stats stats;
93 };
94
95 struct minstrel_sta_info {
96 struct ieee80211_sta *sta;
97
98 unsigned long last_stats_update;
99 unsigned int sp_ack_dur;
100 unsigned int rate_avg;
101
102 unsigned int lowest_rix;
103
104 u8 max_tp_rate[MAX_THR_RATES];
105 u8 max_prob_rate;
106 unsigned int total_packets;
107 unsigned int sample_packets;
108 int sample_deferred;
109
110 unsigned int sample_row;
111 unsigned int sample_column;
112
113 int n_rates;
114 struct minstrel_rate *r;
115 bool prev_sample;
116
117 /* sampling table */
118 u8 *sample_table;
119
120 #ifdef CONFIG_MAC80211_DEBUGFS
121 struct dentry *dbg_stats;
122 struct dentry *dbg_stats_csv;
123 #endif
124 };
125
126 struct minstrel_priv {
127 struct ieee80211_hw *hw;
128 bool has_mrr;
129 unsigned int cw_min;
130 unsigned int cw_max;
131 unsigned int max_retry;
132 unsigned int segment_size;
133 unsigned int update_interval;
134 unsigned int lookaround_rate;
135 unsigned int lookaround_rate_mrr;
136
137 u8 cck_rates[4];
138
139 #ifdef CONFIG_MAC80211_DEBUGFS
140 /*
141 * enable fixed rate processing per RC
142 * - write static index to debugfs:ieee80211/phyX/rc/fixed_rate_idx
143 * - write -1 to enable RC processing again
144 * - setting will be applied on next update
145 */
146 u32 fixed_rate_idx;
147 struct dentry *dbg_fixed_rate;
148 #endif
149 };
150
151 struct minstrel_debugfs_info {
152 size_t len;
153 char buf[];
154 };
155
156 extern const struct rate_control_ops mac80211_minstrel;
157 void minstrel_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir);
158 void minstrel_remove_sta_debugfs(void *priv, void *priv_sta);
159
160 /* Recalculate success probabilities and counters for a given rate using EWMA */
161 void minstrel_calc_rate_stats(struct minstrel_rate_stats *mrs);
162 int minstrel_get_tp_avg(struct minstrel_rate *mr, int prob_ewma);
163
164 /* debugfs */
165 int minstrel_stats_open(struct inode *inode, struct file *file);
166 int minstrel_stats_csv_open(struct inode *inode, struct file *file);
167 ssize_t minstrel_stats_read(struct file *file, char __user *buf, size_t len, loff_t *ppos);
168 int minstrel_stats_release(struct inode *inode, struct file *file);
169
170 #endif
171