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 */
27static inline int
28minstrel_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 */
41static inline int
42minstrel_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
56struct 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
80struct 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
95struct 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
126struct 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
151struct minstrel_debugfs_info {
152	size_t len;
153	char buf[];
154};
155
156extern const struct rate_control_ops mac80211_minstrel;
157void minstrel_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir);
158void minstrel_remove_sta_debugfs(void *priv, void *priv_sta);
159
160/* Recalculate success probabilities and counters for a given rate using EWMA */
161void minstrel_calc_rate_stats(struct minstrel_rate_stats *mrs);
162int minstrel_get_tp_avg(struct minstrel_rate *mr, int prob_ewma);
163
164/* debugfs */
165int minstrel_stats_open(struct inode *inode, struct file *file);
166int minstrel_stats_csv_open(struct inode *inode, struct file *file);
167ssize_t minstrel_stats_read(struct file *file, char __user *buf, size_t len, loff_t *ppos);
168int minstrel_stats_release(struct inode *inode, struct file *file);
169
170#endif
171