/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
 */

#ifndef __RC_MINSTREL_HT_H
#define __RC_MINSTREL_HT_H

#include <linux/bitfield.h>

/* number of highest throughput rates to consider*/
#define MAX_THR_RATES 4
#define SAMPLE_COLUMNS  10      /* number of columns in sample table */

/* scaled fraction values */
#define MINSTREL_SCALE  12
#define MINSTREL_FRAC(val, div) (((val) << MINSTREL_SCALE) / div)
#define MINSTREL_TRUNC(val) ((val) >> MINSTREL_SCALE)

#define EWMA_LEVEL      96      /* ewma weighting factor [/EWMA_DIV] */
#define EWMA_DIV        128

/*
 * Coefficients for moving average with noise filter (period=16),
 * scaled by 10 bits
 *
 * a1 = exp(-pi * sqrt(2) / period)
 * coeff2 = 2 * a1 * cos(sqrt(2) * 2 * pi / period)
 * coeff3 = -sqr(a1)
 * coeff1 = 1 - coeff2 - coeff3
 */
#define MINSTREL_AVG_COEFF1             (MINSTREL_FRAC(1, 1) - \
                                         MINSTREL_AVG_COEFF2 - \
                                         MINSTREL_AVG_COEFF3)
#define MINSTREL_AVG_COEFF2             0x00001499
#define MINSTREL_AVG_COEFF3             -0x0000092e

/*
 * The number of streams can be changed to 2 to reduce code
 * size and memory footprint.
 */
#define MINSTREL_MAX_STREAMS            4
#define MINSTREL_HT_STREAM_GROUPS       4 /* BW(=2) * SGI(=2) */
#define MINSTREL_VHT_STREAM_GROUPS      6 /* BW(=3) * SGI(=2) */

#define MINSTREL_HT_GROUPS_NB   (MINSTREL_MAX_STREAMS *         \
                                 MINSTREL_HT_STREAM_GROUPS)
#define MINSTREL_VHT_GROUPS_NB  (MINSTREL_MAX_STREAMS *         \
                                 MINSTREL_VHT_STREAM_GROUPS)
#define MINSTREL_LEGACY_GROUPS_NB       2
#define MINSTREL_GROUPS_NB      (MINSTREL_HT_GROUPS_NB +        \
                                 MINSTREL_VHT_GROUPS_NB +       \
                                 MINSTREL_LEGACY_GROUPS_NB)

#define MINSTREL_HT_GROUP_0     0
#define MINSTREL_CCK_GROUP      (MINSTREL_HT_GROUP_0 + MINSTREL_HT_GROUPS_NB)
#define MINSTREL_OFDM_GROUP     (MINSTREL_CCK_GROUP + 1)
#define MINSTREL_VHT_GROUP_0    (MINSTREL_OFDM_GROUP + 1)

#define MCS_GROUP_RATES         10

#define MI_RATE_IDX_MASK        GENMASK(3, 0)
#define MI_RATE_GROUP_MASK      GENMASK(15, 4)

#define MI_RATE(_group, _idx)                           \
        (FIELD_PREP(MI_RATE_GROUP_MASK, _group) |       \
         FIELD_PREP(MI_RATE_IDX_MASK, _idx))

#define MI_RATE_IDX(_rate) FIELD_GET(MI_RATE_IDX_MASK, _rate)
#define MI_RATE_GROUP(_rate) FIELD_GET(MI_RATE_GROUP_MASK, _rate)

#define MINSTREL_SAMPLE_RATES           5 /* rates per sample type */
#define MINSTREL_SAMPLE_INTERVAL        (HZ / 50)

struct minstrel_priv {
        struct ieee80211_hw *hw;
        unsigned int cw_min;
        unsigned int cw_max;
        unsigned int max_retry;
        unsigned int segment_size;
        unsigned int update_interval;

        u8 cck_rates[4];
        u8 ofdm_rates[NUM_NL80211_BANDS][8];

#ifdef CONFIG_MAC80211_DEBUGFS
        /*
         * enable fixed rate processing per RC
         *   - write static index to debugfs:ieee80211/phyX/rc/fixed_rate_idx
         *   - write -1 to enable RC processing again
         *   - setting will be applied on next update
         */
        u32 fixed_rate_idx;
#endif
};


struct mcs_group {
        u16 flags;
        u8 streams;
        u8 shift;
        u8 bw;
        u16 duration[MCS_GROUP_RATES];
};

extern const s16 minstrel_cck_bitrates[4];
extern const s16 minstrel_ofdm_bitrates[8];
extern const struct mcs_group minstrel_mcs_groups[];

struct minstrel_rate_stats {
        /* current / last sampling period attempts/success counters */
        u16 attempts, last_attempts;
        u16 success, last_success;

        /* total attempts/success counters */
        u32 att_hist, succ_hist;

        /* prob_avg - moving average of prob */
        u16 prob_avg;
        u16 prob_avg_1;

        /* maximum retry counts */
        u8 retry_count;
        u8 retry_count_rtscts;

        bool retry_updated;
};

enum minstrel_sample_type {
        MINSTREL_SAMPLE_TYPE_INC,
        MINSTREL_SAMPLE_TYPE_JUMP,
        MINSTREL_SAMPLE_TYPE_SLOW,
        __MINSTREL_SAMPLE_TYPE_MAX
};

struct minstrel_mcs_group_data {
        u8 index;
        u8 column;

        /* sorted rate set within a MCS group*/
        u16 max_group_tp_rate[MAX_THR_RATES];
        u16 max_group_prob_rate;

        /* MCS rate statistics */
        struct minstrel_rate_stats rates[MCS_GROUP_RATES];
};

struct minstrel_sample_category {
        u8 sample_group;
        u16 sample_rates[MINSTREL_SAMPLE_RATES];
        u16 cur_sample_rates[MINSTREL_SAMPLE_RATES];
};

struct minstrel_ht_sta {
        struct ieee80211_sta *sta;

        /* ampdu length (average, per sampling interval) */
        unsigned int ampdu_len;
        unsigned int ampdu_packets;

        /* ampdu length (EWMA) */
        unsigned int avg_ampdu_len;

        /* overall sorted rate set */
        u16 max_tp_rate[MAX_THR_RATES];
        u16 max_prob_rate;

        /* time of last status update */
        unsigned long last_stats_update;

        /* overhead time in usec for each frame */
        unsigned int overhead;
        unsigned int overhead_rtscts;
        unsigned int overhead_legacy;
        unsigned int overhead_legacy_rtscts;

        unsigned int total_packets;
        unsigned int sample_packets;

        /* tx flags to add for frames for this sta */
        u32 tx_flags;
        bool use_short_preamble;
        u8 band;

        u8 sample_seq;
        u16 sample_rate;

        unsigned long sample_time;
        struct minstrel_sample_category sample[__MINSTREL_SAMPLE_TYPE_MAX];

        /* Bitfield of supported MCS rates of all groups */
        u16 supported[MINSTREL_GROUPS_NB];

        /* MCS rate group info and statistics */
        struct minstrel_mcs_group_data groups[MINSTREL_GROUPS_NB];
};

void minstrel_ht_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir);
int minstrel_ht_get_tp_avg(struct minstrel_ht_sta *mi, int group, int rate,
                           int prob_avg);

#endif