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 */
39static inline int
40minstrel_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
50static 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
74out:
75	*prev_2 = out_1;
76	*prev_1 = val;
77
78	return val;
79}
80
81struct 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
101struct 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
116struct 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
141struct 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
167struct minstrel_debugfs_info {
168	size_t len;
169	char buf[];
170};
171
172extern const struct rate_control_ops mac80211_minstrel;
173void 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 */
176void minstrel_calc_rate_stats(struct minstrel_priv *mp,
177			      struct minstrel_rate_stats *mrs);
178int minstrel_get_tp_avg(struct minstrel_rate *mr, int prob_avg);
179
180/* debugfs */
181int minstrel_stats_open(struct inode *inode, struct file *file);
182int minstrel_stats_csv_open(struct inode *inode, struct file *file);
183
184#endif
185