/******************************************************************************
 *
 * Copyright(c) 2005 - 2014 Intel Corporation. All rights reserved.
 * Copyright(c) 2013 - 2015 Intel Mobile Communications GmbH
 * Copyright(c) 2016 Intel Deutschland GmbH
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA
 *
 * The full GNU General Public License is included in this distribution in the
 * file called LICENSE.
 *
 * Contact Information:
 *  Intel Linux Wireless <linuxwifi@intel.com>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *
 *****************************************************************************/
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <net/mac80211.h>

#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/delay.h>

#include <linux/workqueue.h>
#include "rs.h"
#include "fw-api.h"
#include "sta.h"
#include "iwl-op-mode.h"
#include "mvm.h"
#include "debugfs.h"

#define RS_NAME "iwl-mvm-rs"

#define IWL_RATE_MAX_WINDOW             62      /* # tx in history window */

/* Calculations of success ratio are done in fixed point where 12800 is 100%.
 * Use this macro when dealing with thresholds consts set as a percentage
 */
#define RS_PERCENT(x) (128 * x)

static u8 rs_ht_to_legacy[] = {
        [IWL_RATE_MCS_0_INDEX] = IWL_RATE_6M_INDEX,
        [IWL_RATE_MCS_1_INDEX] = IWL_RATE_9M_INDEX,
        [IWL_RATE_MCS_2_INDEX] = IWL_RATE_12M_INDEX,
        [IWL_RATE_MCS_3_INDEX] = IWL_RATE_18M_INDEX,
        [IWL_RATE_MCS_4_INDEX] = IWL_RATE_24M_INDEX,
        [IWL_RATE_MCS_5_INDEX] = IWL_RATE_36M_INDEX,
        [IWL_RATE_MCS_6_INDEX] = IWL_RATE_48M_INDEX,
        [IWL_RATE_MCS_7_INDEX] = IWL_RATE_54M_INDEX,
        [IWL_RATE_MCS_8_INDEX] = IWL_RATE_54M_INDEX,
        [IWL_RATE_MCS_9_INDEX] = IWL_RATE_54M_INDEX,
};

static const u8 ant_toggle_lookup[] = {
        [ANT_NONE] = ANT_NONE,
        [ANT_A] = ANT_B,
        [ANT_B] = ANT_C,
        [ANT_AB] = ANT_BC,
        [ANT_C] = ANT_A,
        [ANT_AC] = ANT_AB,
        [ANT_BC] = ANT_AC,
        [ANT_ABC] = ANT_ABC,
};

#define IWL_DECLARE_RATE_INFO(r, s, rp, rn)                           \
        [IWL_RATE_##r##M_INDEX] = { IWL_RATE_##r##M_PLCP,             \
                                    IWL_RATE_HT_SISO_MCS_##s##_PLCP,  \
                                    IWL_RATE_HT_MIMO2_MCS_##s##_PLCP, \
                                    IWL_RATE_VHT_SISO_MCS_##s##_PLCP, \
                                    IWL_RATE_VHT_MIMO2_MCS_##s##_PLCP,\
                                    IWL_RATE_##rp##M_INDEX,           \
                                    IWL_RATE_##rn##M_INDEX }

#define IWL_DECLARE_MCS_RATE(s)                                           \
        [IWL_RATE_MCS_##s##_INDEX] = { IWL_RATE_INVM_PLCP,                \
                                       IWL_RATE_HT_SISO_MCS_##s##_PLCP,   \
                                       IWL_RATE_HT_MIMO2_MCS_##s##_PLCP,  \
                                       IWL_RATE_VHT_SISO_MCS_##s##_PLCP,  \
                                       IWL_RATE_VHT_MIMO2_MCS_##s##_PLCP, \
                                       IWL_RATE_INVM_INDEX,               \
                                       IWL_RATE_INVM_INDEX }

/*
 * Parameter order:
 *   rate, ht rate, prev rate, next rate
 *
 * If there isn't a valid next or previous rate then INV is used which
 * maps to IWL_RATE_INVALID
 *
 */
static const struct iwl_rs_rate_info iwl_rates[IWL_RATE_COUNT] = {
        IWL_DECLARE_RATE_INFO(1, INV, INV, 2),   /*  1mbps */
        IWL_DECLARE_RATE_INFO(2, INV, 1, 5),     /*  2mbps */
        IWL_DECLARE_RATE_INFO(5, INV, 2, 11),    /*5.5mbps */
        IWL_DECLARE_RATE_INFO(11, INV, 9, 12),   /* 11mbps */
        IWL_DECLARE_RATE_INFO(6, 0, 5, 11),      /*  6mbps ; MCS 0 */
        IWL_DECLARE_RATE_INFO(9, INV, 6, 11),    /*  9mbps */
        IWL_DECLARE_RATE_INFO(12, 1, 11, 18),    /* 12mbps ; MCS 1 */
        IWL_DECLARE_RATE_INFO(18, 2, 12, 24),    /* 18mbps ; MCS 2 */
        IWL_DECLARE_RATE_INFO(24, 3, 18, 36),    /* 24mbps ; MCS 3 */
        IWL_DECLARE_RATE_INFO(36, 4, 24, 48),    /* 36mbps ; MCS 4 */
        IWL_DECLARE_RATE_INFO(48, 5, 36, 54),    /* 48mbps ; MCS 5 */
        IWL_DECLARE_RATE_INFO(54, 6, 48, INV),   /* 54mbps ; MCS 6 */
        IWL_DECLARE_MCS_RATE(7),                 /* MCS 7 */
        IWL_DECLARE_MCS_RATE(8),                 /* MCS 8 */
        IWL_DECLARE_MCS_RATE(9),                 /* MCS 9 */
};

enum rs_action {
        RS_ACTION_STAY = 0,
        RS_ACTION_DOWNSCALE = -1,
        RS_ACTION_UPSCALE = 1,
};

enum rs_column_mode {
        RS_INVALID = 0,
        RS_LEGACY,
        RS_SISO,
        RS_MIMO2,
};

#define MAX_NEXT_COLUMNS 7
#define MAX_COLUMN_CHECKS 3

struct rs_tx_column;

typedef bool (*allow_column_func_t) (struct iwl_mvm *mvm,
                                     struct ieee80211_sta *sta,
                                     struct rs_rate *rate,
                                     const struct rs_tx_column *next_col);

struct rs_tx_column {
        enum rs_column_mode mode;
        u8 ant;
        bool sgi;
        enum rs_column next_columns[MAX_NEXT_COLUMNS];
        allow_column_func_t checks[MAX_COLUMN_CHECKS];
};

static bool rs_ant_allow(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
                         struct rs_rate *rate,
                         const struct rs_tx_column *next_col)
{
        return iwl_mvm_bt_coex_is_ant_avail(mvm, next_col->ant);
}

static bool rs_mimo_allow(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
                          struct rs_rate *rate,
                          const struct rs_tx_column *next_col)
{
        struct iwl_mvm_sta *mvmsta;
        struct iwl_mvm_vif *mvmvif;

        if (!sta->ht_cap.ht_supported)
                return false;

        if (sta->smps_mode == IEEE80211_SMPS_STATIC)
                return false;

        if (num_of_ant(iwl_mvm_get_valid_tx_ant(mvm)) < 2)
                return false;

        if (!iwl_mvm_bt_coex_is_mimo_allowed(mvm, sta))
                return false;

        mvmsta = iwl_mvm_sta_from_mac80211(sta);
        mvmvif = iwl_mvm_vif_from_mac80211(mvmsta->vif);

        if (mvm->nvm_data->sku_cap_mimo_disabled)
                return false;

        return true;
}

static bool rs_siso_allow(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
                          struct rs_rate *rate,
                          const struct rs_tx_column *next_col)
{
        if (!sta->ht_cap.ht_supported)
                return false;

        return true;
}

static bool rs_sgi_allow(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
                         struct rs_rate *rate,
                         const struct rs_tx_column *next_col)
{
        struct ieee80211_sta_ht_cap *ht_cap = &sta->ht_cap;
        struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap;

        if (is_ht20(rate) && (ht_cap->cap &
                             IEEE80211_HT_CAP_SGI_20))
                return true;
        if (is_ht40(rate) && (ht_cap->cap &
                             IEEE80211_HT_CAP_SGI_40))
                return true;
        if (is_ht80(rate) && (vht_cap->cap &
                             IEEE80211_VHT_CAP_SHORT_GI_80))
                return true;
        if (is_ht160(rate) && (vht_cap->cap &
                             IEEE80211_VHT_CAP_SHORT_GI_160))
                return true;

        return false;
}

static const struct rs_tx_column rs_tx_columns[] = {
        [RS_COLUMN_LEGACY_ANT_A] = {
                .mode = RS_LEGACY,
                .ant = ANT_A,
                .next_columns = {
                        RS_COLUMN_LEGACY_ANT_B,
                        RS_COLUMN_SISO_ANT_A,
                        RS_COLUMN_MIMO2,
                        RS_COLUMN_INVALID,
                        RS_COLUMN_INVALID,
                        RS_COLUMN_INVALID,
                        RS_COLUMN_INVALID,
                },
                .checks = {
                        rs_ant_allow,
                },
        },
        [RS_COLUMN_LEGACY_ANT_B] = {
                .mode = RS_LEGACY,
                .ant = ANT_B,
                .next_columns = {
                        RS_COLUMN_LEGACY_ANT_A,
                        RS_COLUMN_SISO_ANT_B,
                        RS_COLUMN_MIMO2,
                        RS_COLUMN_INVALID,
                        RS_COLUMN_INVALID,
                        RS_COLUMN_INVALID,
                        RS_COLUMN_INVALID,
                },
                .checks = {
                        rs_ant_allow,
                },
        },
        [RS_COLUMN_SISO_ANT_A] = {
                .mode = RS_SISO,
                .ant = ANT_A,
                .next_columns = {
                        RS_COLUMN_SISO_ANT_B,
                        RS_COLUMN_MIMO2,
                        RS_COLUMN_SISO_ANT_A_SGI,
                        RS_COLUMN_LEGACY_ANT_A,
                        RS_COLUMN_LEGACY_ANT_B,
                        RS_COLUMN_INVALID,
                        RS_COLUMN_INVALID,
                },
                .checks = {
                        rs_siso_allow,
                        rs_ant_allow,
                },
        },
        [RS_COLUMN_SISO_ANT_B] = {
                .mode = RS_SISO,
                .ant = ANT_B,
                .next_columns = {
                        RS_COLUMN_SISO_ANT_A,
                        RS_COLUMN_MIMO2,
                        RS_COLUMN_SISO_ANT_B_SGI,
                        RS_COLUMN_LEGACY_ANT_A,
                        RS_COLUMN_LEGACY_ANT_B,
                        RS_COLUMN_INVALID,
                        RS_COLUMN_INVALID,
                },
                .checks = {
                        rs_siso_allow,
                        rs_ant_allow,
                },
        },
        [RS_COLUMN_SISO_ANT_A_SGI] = {
                .mode = RS_SISO,
                .ant = ANT_A,
                .sgi = true,
                .next_columns = {
                        RS_COLUMN_SISO_ANT_B_SGI,
                        RS_COLUMN_MIMO2_SGI,
                        RS_COLUMN_SISO_ANT_A,
                        RS_COLUMN_LEGACY_ANT_A,
                        RS_COLUMN_LEGACY_ANT_B,
                        RS_COLUMN_INVALID,
                        RS_COLUMN_INVALID,
                },
                .checks = {
                        rs_siso_allow,
                        rs_ant_allow,
                        rs_sgi_allow,
                },
        },
        [RS_COLUMN_SISO_ANT_B_SGI] = {
                .mode = RS_SISO,
                .ant = ANT_B,
                .sgi = true,
                .next_columns = {
                        RS_COLUMN_SISO_ANT_A_SGI,
                        RS_COLUMN_MIMO2_SGI,
                        RS_COLUMN_SISO_ANT_B,
                        RS_COLUMN_LEGACY_ANT_A,
                        RS_COLUMN_LEGACY_ANT_B,
                        RS_COLUMN_INVALID,
                        RS_COLUMN_INVALID,
                },
                .checks = {
                        rs_siso_allow,
                        rs_ant_allow,
                        rs_sgi_allow,
                },
        },
        [RS_COLUMN_MIMO2] = {
                .mode = RS_MIMO2,
                .ant = ANT_AB,
                .next_columns = {
                        RS_COLUMN_SISO_ANT_A,
                        RS_COLUMN_MIMO2_SGI,
                        RS_COLUMN_LEGACY_ANT_A,
                        RS_COLUMN_LEGACY_ANT_B,
                        RS_COLUMN_INVALID,
                        RS_COLUMN_INVALID,
                        RS_COLUMN_INVALID,
                },
                .checks = {
                        rs_mimo_allow,
                },
        },
        [RS_COLUMN_MIMO2_SGI] = {
                .mode = RS_MIMO2,
                .ant = ANT_AB,
                .sgi = true,
                .next_columns = {
                        RS_COLUMN_SISO_ANT_A_SGI,
                        RS_COLUMN_MIMO2,
                        RS_COLUMN_LEGACY_ANT_A,
                        RS_COLUMN_LEGACY_ANT_B,
                        RS_COLUMN_INVALID,
                        RS_COLUMN_INVALID,
                        RS_COLUMN_INVALID,
                },
                .checks = {
                        rs_mimo_allow,
                        rs_sgi_allow,
                },
        },
};

static inline u8 rs_extract_rate(u32 rate_n_flags)
{
        /* also works for HT because bits 7:6 are zero there */
        return (u8)(rate_n_flags & RATE_LEGACY_RATE_MSK);
}

static int iwl_hwrate_to_plcp_idx(u32 rate_n_flags)
{
        int idx = 0;

        if (rate_n_flags & RATE_MCS_HT_MSK) {
                idx = rate_n_flags & RATE_HT_MCS_RATE_CODE_MSK;
                idx += IWL_RATE_MCS_0_INDEX;

                /* skip 9M not supported in HT*/
                if (idx >= IWL_RATE_9M_INDEX)
                        idx += 1;
                if ((idx >= IWL_FIRST_HT_RATE) && (idx <= IWL_LAST_HT_RATE))
                        return idx;
        } else if (rate_n_flags & RATE_MCS_VHT_MSK) {
                idx = rate_n_flags & RATE_VHT_MCS_RATE_CODE_MSK;
                idx += IWL_RATE_MCS_0_INDEX;

                /* skip 9M not supported in VHT*/
                if (idx >= IWL_RATE_9M_INDEX)
                        idx++;
                if ((idx >= IWL_FIRST_VHT_RATE) && (idx <= IWL_LAST_VHT_RATE))
                        return idx;
        } else {
                /* legacy rate format, search for match in table */

                u8 legacy_rate = rs_extract_rate(rate_n_flags);
                for (idx = 0; idx < ARRAY_SIZE(iwl_rates); idx++)
                        if (iwl_rates[idx].plcp == legacy_rate)
                                return idx;
        }

        return IWL_RATE_INVALID;
}

static void rs_rate_scale_perform(struct iwl_mvm *mvm,
                                  struct ieee80211_sta *sta,
                                  struct iwl_lq_sta *lq_sta,
                                  int tid, bool ndp);
static void rs_fill_lq_cmd(struct iwl_mvm *mvm,
                           struct ieee80211_sta *sta,
                           struct iwl_lq_sta *lq_sta,
                           const struct rs_rate *initial_rate);
static void rs_stay_in_table(struct iwl_lq_sta *lq_sta, bool force_search);

/**
 * The following tables contain the expected throughput metrics for all rates
 *
 *      1, 2, 5.5, 11, 6, 9, 12, 18, 24, 36, 48, 54, 60 MBits
 *
 * where invalid entries are zeros.
 *
 * CCK rates are only valid in legacy table and will only be used in G
 * (2.4 GHz) band.
 */

static const u16 expected_tpt_legacy[IWL_RATE_COUNT] = {
        7, 13, 35, 58, 40, 57, 72, 98, 121, 154, 177, 186, 0, 0, 0
};

/* Expected TpT tables. 4 indexes:
 * 0 - NGI, 1 - SGI, 2 - AGG+NGI, 3 - AGG+SGI
 */
static const u16 expected_tpt_siso_20MHz[4][IWL_RATE_COUNT] = {
        {0, 0, 0, 0, 42, 0,  76, 102, 124, 159, 183, 193, 202, 216, 0},
        {0, 0, 0, 0, 46, 0,  82, 110, 132, 168, 192, 202, 210, 225, 0},
        {0, 0, 0, 0, 49, 0,  97, 145, 192, 285, 375, 420, 464, 551, 0},
        {0, 0, 0, 0, 54, 0, 108, 160, 213, 315, 415, 465, 513, 608, 0},
};

static const u16 expected_tpt_siso_40MHz[4][IWL_RATE_COUNT] = {
        {0, 0, 0, 0,  77, 0, 127, 160, 184, 220, 242, 250,  257,  269,  275},
        {0, 0, 0, 0,  83, 0, 135, 169, 193, 229, 250, 257,  264,  275,  280},
        {0, 0, 0, 0, 101, 0, 199, 295, 389, 570, 744, 828,  911, 1070, 1173},
        {0, 0, 0, 0, 112, 0, 220, 326, 429, 629, 819, 912, 1000, 1173, 1284},
};

static const u16 expected_tpt_siso_80MHz[4][IWL_RATE_COUNT] = {
        {0, 0, 0, 0, 130, 0, 191, 223, 244,  273,  288,  294,  298,  305,  308},
        {0, 0, 0, 0, 138, 0, 200, 231, 251,  279,  293,  298,  302,  308,  312},
        {0, 0, 0, 0, 217, 0, 429, 634, 834, 1220, 1585, 1760, 1931, 2258, 2466},
        {0, 0, 0, 0, 241, 0, 475, 701, 921, 1343, 1741, 1931, 2117, 2468, 2691},
};

static const u16 expected_tpt_siso_160MHz[4][IWL_RATE_COUNT] = {
        {0, 0, 0, 0, 191, 0, 244, 288,  298,  308,  313,  318,  323,  328,  330},
        {0, 0, 0, 0, 200, 0, 251, 293,  302,  312,  317,  322,  327,  332,  334},
        {0, 0, 0, 0, 439, 0, 875, 1307, 1736, 2584, 3419, 3831, 4240, 5049, 5581},
        {0, 0, 0, 0, 488, 0, 972, 1451, 1925, 2864, 3785, 4240, 4691, 5581, 6165},
};

static const u16 expected_tpt_mimo2_20MHz[4][IWL_RATE_COUNT] = {
        {0, 0, 0, 0,  74, 0, 123, 155, 179, 213, 235, 243, 250,  261, 0},
        {0, 0, 0, 0,  81, 0, 131, 164, 187, 221, 242, 250, 256,  267, 0},
        {0, 0, 0, 0,  98, 0, 193, 286, 375, 550, 718, 799, 878, 1032, 0},
        {0, 0, 0, 0, 109, 0, 214, 316, 414, 607, 790, 879, 965, 1132, 0},
};

static const u16 expected_tpt_mimo2_40MHz[4][IWL_RATE_COUNT] = {
        {0, 0, 0, 0, 123, 0, 182, 214, 235,  264,  279,  285,  289,  296,  300},
        {0, 0, 0, 0, 131, 0, 191, 222, 242,  270,  284,  289,  293,  300,  303},
        {0, 0, 0, 0, 200, 0, 390, 571, 741, 1067, 1365, 1505, 1640, 1894, 2053},
        {0, 0, 0, 0, 221, 0, 430, 630, 816, 1169, 1490, 1641, 1784, 2053, 2221},
};

static const u16 expected_tpt_mimo2_80MHz[4][IWL_RATE_COUNT] = {
        {0, 0, 0, 0, 182, 0, 240,  264,  278,  299,  308,  311,  313,  317,  319},
        {0, 0, 0, 0, 190, 0, 247,  269,  282,  302,  310,  313,  315,  319,  320},
        {0, 0, 0, 0, 428, 0, 833, 1215, 1577, 2254, 2863, 3147, 3418, 3913, 4219},
        {0, 0, 0, 0, 474, 0, 920, 1338, 1732, 2464, 3116, 3418, 3705, 4225, 4545},
};

static const u16 expected_tpt_mimo2_160MHz[4][IWL_RATE_COUNT] = {
        {0, 0, 0, 0, 240, 0, 278,  308,  313,  319,  322,  324,  328,  330,   334},
        {0, 0, 0, 0, 247, 0, 282,  310,  315,  320,  323,  325,  329,  332,   338},
        {0, 0, 0, 0, 875, 0, 1735, 2582, 3414, 5043, 6619, 7389, 8147, 9629,  10592},
        {0, 0, 0, 0, 971, 0, 1925, 2861, 3779, 5574, 7304, 8147, 8976, 10592, 11640},
};

/* mbps, mcs */
static const struct iwl_rate_mcs_info iwl_rate_mcs[IWL_RATE_COUNT] = {
        {  "1", "BPSK DSSS"},
        {  "2", "QPSK DSSS"},
        {"5.5", "BPSK CCK"},
        { "11", "QPSK CCK"},
        {  "6", "BPSK 1/2"},
        {  "9", "BPSK 1/2"},
        { "12", "QPSK 1/2"},
        { "18", "QPSK 3/4"},
        { "24", "16QAM 1/2"},
        { "36", "16QAM 3/4"},
        { "48", "64QAM 2/3"},
        { "54", "64QAM 3/4"},
        { "60", "64QAM 5/6"},
};

#define MCS_INDEX_PER_STREAM    (8)

static const char *rs_pretty_ant(u8 ant)
{
        static const char * const ant_name[] = {
                [ANT_NONE] = "None",
                [ANT_A]    = "A",
                [ANT_B]    = "B",
                [ANT_AB]   = "AB",
                [ANT_C]    = "C",
                [ANT_AC]   = "AC",
                [ANT_BC]   = "BC",
                [ANT_ABC]  = "ABC",
        };

        if (ant > ANT_ABC)
                return "UNKNOWN";

        return ant_name[ant];
}

static const char *rs_pretty_lq_type(enum iwl_table_type type)
{
        static const char * const lq_types[] = {
                [LQ_NONE] = "NONE",
                [LQ_LEGACY_A] = "LEGACY_A",
                [LQ_LEGACY_G] = "LEGACY_G",
                [LQ_HT_SISO] = "HT SISO",
                [LQ_HT_MIMO2] = "HT MIMO",
                [LQ_VHT_SISO] = "VHT SISO",
                [LQ_VHT_MIMO2] = "VHT MIMO",
        };

        if (type < LQ_NONE || type >= LQ_MAX)
                return "UNKNOWN";

        return lq_types[type];
}

static char *rs_pretty_rate(const struct rs_rate *rate)
{
        static char buf[40];
        static const char * const legacy_rates[] = {
                [IWL_RATE_1M_INDEX] = "1M",
                [IWL_RATE_2M_INDEX] = "2M",
                [IWL_RATE_5M_INDEX] = "5.5M",
                [IWL_RATE_11M_INDEX] = "11M",
                [IWL_RATE_6M_INDEX] = "6M",
                [IWL_RATE_9M_INDEX] = "9M",
                [IWL_RATE_12M_INDEX] = "12M",
                [IWL_RATE_18M_INDEX] = "18M",
                [IWL_RATE_24M_INDEX] = "24M",
                [IWL_RATE_36M_INDEX] = "36M",
                [IWL_RATE_48M_INDEX] = "48M",
                [IWL_RATE_54M_INDEX] = "54M",
        };
        static const char *const ht_vht_rates[] = {
                [IWL_RATE_MCS_0_INDEX] = "MCS0",
                [IWL_RATE_MCS_1_INDEX] = "MCS1",
                [IWL_RATE_MCS_2_INDEX] = "MCS2",
                [IWL_RATE_MCS_3_INDEX] = "MCS3",
                [IWL_RATE_MCS_4_INDEX] = "MCS4",
                [IWL_RATE_MCS_5_INDEX] = "MCS5",
                [IWL_RATE_MCS_6_INDEX] = "MCS6",
                [IWL_RATE_MCS_7_INDEX] = "MCS7",
                [IWL_RATE_MCS_8_INDEX] = "MCS8",
                [IWL_RATE_MCS_9_INDEX] = "MCS9",
        };
        const char *rate_str;

        if (is_type_legacy(rate->type) && (rate->index <= IWL_RATE_54M_INDEX))
                rate_str = legacy_rates[rate->index];
        else if ((is_type_ht(rate->type) || is_type_vht(rate->type)) &&
                 (rate->index >= IWL_RATE_MCS_0_INDEX) &&
                 (rate->index <= IWL_RATE_MCS_9_INDEX))
                rate_str = ht_vht_rates[rate->index];
        else
                rate_str = "BAD_RATE";

        sprintf(buf, "(%s|%s|%s)", rs_pretty_lq_type(rate->type),
                rs_pretty_ant(rate->ant), rate_str);
        return buf;
}

static inline void rs_dump_rate(struct iwl_mvm *mvm, const struct rs_rate *rate,
                                const char *prefix)
{
        IWL_DEBUG_RATE(mvm,
                       "%s: %s BW: %d SGI: %d LDPC: %d STBC: %d\n",
                       prefix, rs_pretty_rate(rate), rate->bw,
                       rate->sgi, rate->ldpc, rate->stbc);
}

static void rs_rate_scale_clear_window(struct iwl_rate_scale_data *window)
{
        window->data = 0;
        window->success_counter = 0;
        window->success_ratio = IWL_INVALID_VALUE;
        window->counter = 0;
        window->average_tpt = IWL_INVALID_VALUE;
}

static void rs_rate_scale_clear_tbl_windows(struct iwl_mvm *mvm,
                                            struct iwl_scale_tbl_info *tbl)
{
        int i;

        IWL_DEBUG_RATE(mvm, "Clearing up window stats\n");
        for (i = 0; i < IWL_RATE_COUNT; i++)
                rs_rate_scale_clear_window(&tbl->win[i]);

        for (i = 0; i < ARRAY_SIZE(tbl->tpc_win); i++)
                rs_rate_scale_clear_window(&tbl->tpc_win[i]);
}

static inline u8 rs_is_valid_ant(u8 valid_antenna, u8 ant_type)
{
        return (ant_type & valid_antenna) == ant_type;
}

static int rs_tl_turn_on_agg_for_tid(struct iwl_mvm *mvm,
                                     struct iwl_lq_sta *lq_data, u8 tid,
                                     struct ieee80211_sta *sta)
{
        int ret = -EAGAIN;

        IWL_DEBUG_HT(mvm, "Starting Tx agg: STA: %pM tid: %d\n",
                     sta->addr, tid);
        ret = ieee80211_start_tx_ba_session(sta, tid, 5000);
        if (ret == -EAGAIN) {
                /*
                 * driver and mac80211 is out of sync
                 * this might be cause by reloading firmware
                 * stop the tx ba session here
                 */
                IWL_ERR(mvm, "Fail start Tx agg on tid: %d\n",
                        tid);
                ieee80211_stop_tx_ba_session(sta, tid);
        }
        return ret;
}

static void rs_tl_turn_on_agg(struct iwl_mvm *mvm, u8 tid,
                              struct iwl_lq_sta *lq_data,
                              struct ieee80211_sta *sta)
{
        if (tid < IWL_MAX_TID_COUNT)
                rs_tl_turn_on_agg_for_tid(mvm, lq_data, tid, sta);
        else
                IWL_ERR(mvm, "tid exceeds max TID count: %d/%d\n",
                        tid, IWL_MAX_TID_COUNT);
}

static inline int get_num_of_ant_from_rate(u32 rate_n_flags)
{
        return !!(rate_n_flags & RATE_MCS_ANT_A_MSK) +
               !!(rate_n_flags & RATE_MCS_ANT_B_MSK) +
               !!(rate_n_flags & RATE_MCS_ANT_C_MSK);
}

/*
 * Static function to get the expected throughput from an iwl_scale_tbl_info
 * that wraps a NULL pointer check
 */
static s32 get_expected_tpt(struct iwl_scale_tbl_info *tbl, int rs_index)
{
        if (tbl->expected_tpt)
                return tbl->expected_tpt[rs_index];
        return 0;
}

/**
 * rs_collect_tx_data - Update the success/failure sliding window
 *
 * We keep a sliding window of the last 62 packets transmitted
 * at this rate.  window->data contains the bitmask of successful
 * packets.
 */
static int _rs_collect_tx_data(struct iwl_mvm *mvm,
                               struct iwl_scale_tbl_info *tbl,
                               int scale_index, int attempts, int successes,
                               struct iwl_rate_scale_data *window)
{
        static const u64 mask = (((u64)1) << (IWL_RATE_MAX_WINDOW - 1));
        s32 fail_count, tpt;

        /* Get expected throughput */
        tpt = get_expected_tpt(tbl, scale_index);

        /*
         * Keep track of only the latest 62 tx frame attempts in this rate's
         * history window; anything older isn't really relevant any more.
         * If we have filled up the sliding window, drop the oldest attempt;
         * if the oldest attempt (highest bit in bitmap) shows "success",
         * subtract "1" from the success counter (this is the main reason
         * we keep these bitmaps!).
         */
        while (attempts > 0) {
                if (window->counter >= IWL_RATE_MAX_WINDOW) {
                        /* remove earliest */
                        window->counter = IWL_RATE_MAX_WINDOW - 1;

                        if (window->data & mask) {
                                window->data &= ~mask;
                                window->success_counter--;
                        }
                }

                /* Increment frames-attempted counter */
                window->counter++;

                /* Shift bitmap by one frame to throw away oldest history */
                window->data <<= 1;

                /* Mark the most recent #successes attempts as successful */
                if (successes > 0) {
                        window->success_counter++;
                        window->data |= 0x1;
                        successes--;
                }

                attempts--;
        }

        /* Calculate current success ratio, avoid divide-by-0! */
        if (window->counter > 0)
                window->success_ratio = 128 * (100 * window->success_counter)
                                        / window->counter;
        else
                window->success_ratio = IWL_INVALID_VALUE;

        fail_count = window->counter - window->success_counter;

        /* Calculate average throughput, if we have enough history. */
        if ((fail_count >= IWL_MVM_RS_RATE_MIN_FAILURE_TH) ||
            (window->success_counter >= IWL_MVM_RS_RATE_MIN_SUCCESS_TH))
                window->average_tpt = (window->success_ratio * tpt + 64) / 128;
        else
                window->average_tpt = IWL_INVALID_VALUE;

        return 0;
}

static int rs_collect_tpc_data(struct iwl_mvm *mvm,
                               struct iwl_lq_sta *lq_sta,
                               struct iwl_scale_tbl_info *tbl,
                               int scale_index, int attempts, int successes,
                               u8 reduced_txp)
{
        struct iwl_rate_scale_data *window = NULL;

        if (WARN_ON_ONCE(reduced_txp > TPC_MAX_REDUCTION))
                return -EINVAL;

        window = &tbl->tpc_win[reduced_txp];
        return  _rs_collect_tx_data(mvm, tbl, scale_index, attempts, successes,
                                    window);
}

static int rs_collect_tlc_data(struct iwl_mvm *mvm,
                               struct iwl_lq_sta *lq_sta,
                               struct iwl_scale_tbl_info *tbl,
                               int scale_index, int attempts, int successes)
{
        struct iwl_rate_scale_data *window = NULL;

        if (scale_index < 0 || scale_index >= IWL_RATE_COUNT)
                return -EINVAL;

        if (tbl->column != RS_COLUMN_INVALID) {
                struct lq_sta_pers *pers = &lq_sta->pers;

                pers->tx_stats[tbl->column][scale_index].total += attempts;
                pers->tx_stats[tbl->column][scale_index].success += successes;
        }

        /* Select window for current tx bit rate */
        window = &(tbl->win[scale_index]);
        return _rs_collect_tx_data(mvm, tbl, scale_index, attempts, successes,
                                   window);
}

/* Convert rs_rate object into ucode rate bitmask */
static u32 ucode_rate_from_rs_rate(struct iwl_mvm *mvm,
                                  struct rs_rate *rate)
{
        u32 ucode_rate = 0;
        int index = rate->index;

        ucode_rate |= ((rate->ant << RATE_MCS_ANT_POS) &
                         RATE_MCS_ANT_ABC_MSK);

        if (is_legacy(rate)) {
                ucode_rate |= iwl_rates[index].plcp;
                if (index >= IWL_FIRST_CCK_RATE && index <= IWL_LAST_CCK_RATE)
                        ucode_rate |= RATE_MCS_CCK_MSK;
                return ucode_rate;
        }

        if (is_ht(rate)) {
                if (index < IWL_FIRST_HT_RATE || index > IWL_LAST_HT_RATE) {
                        IWL_ERR(mvm, "Invalid HT rate index %d\n", index);
                        index = IWL_LAST_HT_RATE;
                }
                ucode_rate |= RATE_MCS_HT_MSK;

                if (is_ht_siso(rate))
                        ucode_rate |= iwl_rates[index].plcp_ht_siso;
                else if (is_ht_mimo2(rate))
                        ucode_rate |= iwl_rates[index].plcp_ht_mimo2;
                else
                        WARN_ON_ONCE(1);
        } else if (is_vht(rate)) {
                if (index < IWL_FIRST_VHT_RATE || index > IWL_LAST_VHT_RATE) {
                        IWL_ERR(mvm, "Invalid VHT rate index %d\n", index);
                        index = IWL_LAST_VHT_RATE;
                }
                ucode_rate |= RATE_MCS_VHT_MSK;
                if (is_vht_siso(rate))
                        ucode_rate |= iwl_rates[index].plcp_vht_siso;
                else if (is_vht_mimo2(rate))
                        ucode_rate |= iwl_rates[index].plcp_vht_mimo2;
                else
                        WARN_ON_ONCE(1);

        } else {
                IWL_ERR(mvm, "Invalid rate->type %d\n", rate->type);
        }

        if (is_siso(rate) && rate->stbc) {
                /* To enable STBC we need to set both a flag and ANT_AB */
                ucode_rate |= RATE_MCS_ANT_AB_MSK;
                ucode_rate |= RATE_MCS_VHT_STBC_MSK;
        }

        ucode_rate |= rate->bw;
        if (rate->sgi)
                ucode_rate |= RATE_MCS_SGI_MSK;
        if (rate->ldpc)
                ucode_rate |= RATE_MCS_LDPC_MSK;

        return ucode_rate;
}

/* Convert a ucode rate into an rs_rate object */
static int rs_rate_from_ucode_rate(const u32 ucode_rate,
                                   enum nl80211_band band,
                                   struct rs_rate *rate)
{
        u32 ant_msk = ucode_rate & RATE_MCS_ANT_ABC_MSK;
        u8 num_of_ant = get_num_of_ant_from_rate(ucode_rate);
        u8 nss;

        memset(rate, 0, sizeof(*rate));
        rate->index = iwl_hwrate_to_plcp_idx(ucode_rate);

        if (rate->index == IWL_RATE_INVALID)
                return -EINVAL;

        rate->ant = (ant_msk >> RATE_MCS_ANT_POS);

        /* Legacy */
        if (!(ucode_rate & RATE_MCS_HT_MSK) &&
            !(ucode_rate & RATE_MCS_VHT_MSK)) {
                if (num_of_ant == 1) {
                        if (band == NL80211_BAND_5GHZ)
                                rate->type = LQ_LEGACY_A;
                        else
                                rate->type = LQ_LEGACY_G;
                }

                return 0;
        }

        /* HT or VHT */
        if (ucode_rate & RATE_MCS_SGI_MSK)
                rate->sgi = true;
        if (ucode_rate & RATE_MCS_LDPC_MSK)
                rate->ldpc = true;
        if (ucode_rate & RATE_MCS_VHT_STBC_MSK)
                rate->stbc = true;
        if (ucode_rate & RATE_MCS_BF_MSK)
                rate->bfer = true;

        rate->bw = ucode_rate & RATE_MCS_CHAN_WIDTH_MSK;

        if (ucode_rate & RATE_MCS_HT_MSK) {
                nss = ((ucode_rate & RATE_HT_MCS_NSS_MSK) >>
                       RATE_HT_MCS_NSS_POS) + 1;

                if (nss == 1) {
                        rate->type = LQ_HT_SISO;
                        WARN_ONCE(!rate->stbc && !rate->bfer && num_of_ant != 1,
                                  "stbc %d bfer %d",
                                  rate->stbc, rate->bfer);
                } else if (nss == 2) {
                        rate->type = LQ_HT_MIMO2;
                        WARN_ON_ONCE(num_of_ant != 2);
                } else {
                        WARN_ON_ONCE(1);
                }
        } else if (ucode_rate & RATE_MCS_VHT_MSK) {
                nss = ((ucode_rate & RATE_VHT_MCS_NSS_MSK) >>
                       RATE_VHT_MCS_NSS_POS) + 1;

                if (nss == 1) {
                        rate->type = LQ_VHT_SISO;
                        WARN_ONCE(!rate->stbc && !rate->bfer && num_of_ant != 1,
                                  "stbc %d bfer %d",
                                  rate->stbc, rate->bfer);
                } else if (nss == 2) {
                        rate->type = LQ_VHT_MIMO2;
                        WARN_ON_ONCE(num_of_ant != 2);
                } else {
                        WARN_ON_ONCE(1);
                }
        }

        WARN_ON_ONCE(rate->bw == RATE_MCS_CHAN_WIDTH_80 &&
                     !is_vht(rate));

        return 0;
}

/* switch to another antenna/antennas and return 1 */
/* if no other valid antenna found, return 0 */
static int rs_toggle_antenna(u32 valid_ant, struct rs_rate *rate)
{
        u8 new_ant_type;

        if (!rate->ant || rate->ant > ANT_ABC)
                return 0;

        if (!rs_is_valid_ant(valid_ant, rate->ant))
                return 0;

        new_ant_type = ant_toggle_lookup[rate->ant];

        while ((new_ant_type != rate->ant) &&
               !rs_is_valid_ant(valid_ant, new_ant_type))
                new_ant_type = ant_toggle_lookup[new_ant_type];

        if (new_ant_type == rate->ant)
                return 0;

        rate->ant = new_ant_type;

        return 1;
}

static u16 rs_get_supported_rates(struct iwl_lq_sta *lq_sta,
                                  struct rs_rate *rate)
{
        if (is_legacy(rate))
                return lq_sta->active_legacy_rate;
        else if (is_siso(rate))
                return lq_sta->active_siso_rate;
        else if (is_mimo2(rate))
                return lq_sta->active_mimo2_rate;

        WARN_ON_ONCE(1);
        return 0;
}

static u16 rs_get_adjacent_rate(struct iwl_mvm *mvm, u8 index, u16 rate_mask,
                                int rate_type)
{
        u8 high = IWL_RATE_INVALID;
        u8 low = IWL_RATE_INVALID;

        /* 802.11A or ht walks to the next literal adjacent rate in
         * the rate table */
        if (is_type_a_band(rate_type) || !is_type_legacy(rate_type)) {
                int i;
                u32 mask;

                /* Find the previous rate that is in the rate mask */
                i = index - 1;
                for (mask = (1 << i); i >= 0; i--, mask >>= 1) {
                        if (rate_mask & mask) {
                                low = i;
                                break;
                        }
                }

                /* Find the next rate that is in the rate mask */
                i = index + 1;
                for (mask = (1 << i); i < IWL_RATE_COUNT; i++, mask <<= 1) {
                        if (rate_mask & mask) {
                                high = i;
                                break;
                        }
                }

                return (high << 8) | low;
        }

        low = index;

        while (low != IWL_RATE_INVALID) {
                low = iwl_rates[low].prev_rs;
                if (low == IWL_RATE_INVALID)
                        break;
                if (rate_mask & (1 << low))
                        break;
        }

        high = index;
        while (high != IWL_RATE_INVALID) {
                high = iwl_rates[high].next_rs;
                if (high == IWL_RATE_INVALID)
                        break;
                if (rate_mask & (1 << high))
                        break;
        }

        return (high << 8) | low;
}

static inline bool rs_rate_supported(struct iwl_lq_sta *lq_sta,
                                     struct rs_rate *rate)
{
        return BIT(rate->index) & rs_get_supported_rates(lq_sta, rate);
}

/* Get the next supported lower rate in the current column.
 * Return true if bottom rate in the current column was reached
 */
static bool rs_get_lower_rate_in_column(struct iwl_lq_sta *lq_sta,
                                        struct rs_rate *rate)
{
        u8 low;
        u16 high_low;
        u16 rate_mask;
        struct iwl_mvm *mvm = lq_sta->pers.drv;

        rate_mask = rs_get_supported_rates(lq_sta, rate);
        high_low = rs_get_adjacent_rate(mvm, rate->index, rate_mask,
                                        rate->type);
        low = high_low & 0xff;

        /* Bottom rate of column reached */
        if (low == IWL_RATE_INVALID)
                return true;

        rate->index = low;
        return false;
}

/* Get the next rate to use following a column downgrade */
static void rs_get_lower_rate_down_column(struct iwl_lq_sta *lq_sta,
                                          struct rs_rate *rate)
{
        struct iwl_mvm *mvm = lq_sta->pers.drv;

        if (is_legacy(rate)) {
                /* No column to downgrade from Legacy */
                return;
        } else if (is_siso(rate)) {
                /* Downgrade to Legacy if we were in SISO */
                if (lq_sta->band == NL80211_BAND_5GHZ)
                        rate->type = LQ_LEGACY_A;
                else
                        rate->type = LQ_LEGACY_G;

                rate->bw = RATE_MCS_CHAN_WIDTH_20;

                WARN_ON_ONCE(rate->index < IWL_RATE_MCS_0_INDEX ||
                             rate->index > IWL_RATE_MCS_9_INDEX);

                rate->index = rs_ht_to_legacy[rate->index];
                rate->ldpc = false;
        } else {
                /* Downgrade to SISO with same MCS if in MIMO  */
                rate->type = is_vht_mimo2(rate) ?
                        LQ_VHT_SISO : LQ_HT_SISO;
        }

        if (num_of_ant(rate->ant) > 1)
                rate->ant = first_antenna(iwl_mvm_get_valid_tx_ant(mvm));

        /* Relevant in both switching to SISO or Legacy */
        rate->sgi = false;

        if (!rs_rate_supported(lq_sta, rate))
                rs_get_lower_rate_in_column(lq_sta, rate);
}

/* Check if both rates are identical
 * allow_ant_mismatch enables matching a SISO rate on ANT_A or ANT_B
 * with a rate indicating STBC/BFER and ANT_AB.
 */
static inline bool rs_rate_equal(struct rs_rate *a,
                                 struct rs_rate *b,
                                 bool allow_ant_mismatch)

{
        bool ant_match = (a->ant == b->ant) && (a->stbc == b->stbc) &&
                (a->bfer == b->bfer);

        if (allow_ant_mismatch) {
                if (a->stbc || a->bfer) {
                        WARN_ONCE(a->ant != ANT_AB, "stbc %d bfer %d ant %d",
                                  a->stbc, a->bfer, a->ant);
                        ant_match |= (b->ant == ANT_A || b->ant == ANT_B);
                } else if (b->stbc || b->bfer) {
                        WARN_ONCE(b->ant != ANT_AB, "stbc %d bfer %d ant %d",
                                  b->stbc, b->bfer, b->ant);
                        ant_match |= (a->ant == ANT_A || a->ant == ANT_B);
                }
        }

        return (a->type == b->type) && (a->bw == b->bw) && (a->sgi == b->sgi) &&
                (a->ldpc == b->ldpc) && (a->index == b->index) && ant_match;
}

/* Check if both rates share the same column */
static inline bool rs_rate_column_match(struct rs_rate *a,
                                        struct rs_rate *b)
{
        bool ant_match;

        if (a->stbc || a->bfer)
                ant_match = (b->ant == ANT_A || b->ant == ANT_B);
        else
                ant_match = (a->ant == b->ant);

        return (a->type == b->type) && (a->bw == b->bw) && (a->sgi == b->sgi)
                && ant_match;
}

static inline enum rs_column rs_get_column_from_rate(struct rs_rate *rate)
{
        if (is_legacy(rate)) {
                if (rate->ant == ANT_A)
                        return RS_COLUMN_LEGACY_ANT_A;

                if (rate->ant == ANT_B)
                        return RS_COLUMN_LEGACY_ANT_B;

                goto err;
        }

        if (is_siso(rate)) {
                if (rate->ant == ANT_A || rate->stbc || rate->bfer)
                        return rate->sgi ? RS_COLUMN_SISO_ANT_A_SGI :
                                RS_COLUMN_SISO_ANT_A;

                if (rate->ant == ANT_B)
                        return rate->sgi ? RS_COLUMN_SISO_ANT_B_SGI :
                                RS_COLUMN_SISO_ANT_B;

                goto err;
        }

        if (is_mimo(rate))
                return rate->sgi ? RS_COLUMN_MIMO2_SGI : RS_COLUMN_MIMO2;

err:
        return RS_COLUMN_INVALID;
}

static u8 rs_get_tid(struct ieee80211_hdr *hdr)
{
        u8 tid = IWL_MAX_TID_COUNT;

        if (ieee80211_is_data_qos(hdr->frame_control)) {
                u8 *qc = ieee80211_get_qos_ctl(hdr);
                tid = qc[0] & 0xf;
        }

        if (unlikely(tid > IWL_MAX_TID_COUNT))
                tid = IWL_MAX_TID_COUNT;

        return tid;
}

void iwl_mvm_rs_tx_status(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
                          int tid, struct ieee80211_tx_info *info, bool ndp)
{
        int legacy_success;
        int retries;
        int i;
        struct iwl_lq_cmd *table;
        u32 lq_hwrate;
        struct rs_rate lq_rate, tx_resp_rate;
        struct iwl_scale_tbl_info *curr_tbl, *other_tbl, *tmp_tbl;
        u8 reduced_txp = (uintptr_t)info->status.status_driver_data[0];
        u32 tx_resp_hwrate = (uintptr_t)info->status.status_driver_data[1];
        struct iwl_mvm_sta *mvmsta = iwl_mvm_sta_from_mac80211(sta);
        struct iwl_lq_sta *lq_sta = &mvmsta->lq_sta;
        bool allow_ant_mismatch = fw_has_api(&mvm->fw->ucode_capa,
                                             IWL_UCODE_TLV_API_LQ_SS_PARAMS);

        /* Treat uninitialized rate scaling data same as non-existing. */
        if (!lq_sta) {
                IWL_DEBUG_RATE(mvm, "Station rate scaling not created yet.\n");
                return;
        } else if (!lq_sta->pers.drv) {
                IWL_DEBUG_RATE(mvm, "Rate scaling not initialized yet.\n");
                return;
        }

        /* This packet was aggregated but doesn't carry status info */
        if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
            !(info->flags & IEEE80211_TX_STAT_AMPDU))
                return;

        rs_rate_from_ucode_rate(tx_resp_hwrate, info->band, &tx_resp_rate);

#ifdef CONFIG_MAC80211_DEBUGFS
        /* Disable last tx check if we are debugging with fixed rate but
         * update tx stats */
        if (lq_sta->pers.dbg_fixed_rate) {
                int index = tx_resp_rate.index;
                enum rs_column column;
                int attempts, success;

                column = rs_get_column_from_rate(&tx_resp_rate);
                if (WARN_ONCE(column == RS_COLUMN_INVALID,
                              "Can't map rate 0x%x to column",
                              tx_resp_hwrate))
                        return;

                if (info->flags & IEEE80211_TX_STAT_AMPDU) {
                        attempts = info->status.ampdu_len;
                        success = info->status.ampdu_ack_len;
                } else {
                        attempts = info->status.rates[0].count;
                        success = !!(info->flags & IEEE80211_TX_STAT_ACK);
                }

                lq_sta->pers.tx_stats[column][index].total += attempts;
                lq_sta->pers.tx_stats[column][index].success += success;

                IWL_DEBUG_RATE(mvm, "Fixed rate 0x%x success %d attempts %d\n",
                               tx_resp_hwrate, success, attempts);
                return;
        }
#endif

        if (time_after(jiffies,
                       (unsigned long)(lq_sta->last_tx +
                                       (IWL_MVM_RS_IDLE_TIMEOUT * HZ)))) {
                int t;

                IWL_DEBUG_RATE(mvm, "Tx idle for too long. reinit rs\n");
                for (t = 0; t < IWL_MAX_TID_COUNT; t++)
                        ieee80211_stop_tx_ba_session(sta, t);

                iwl_mvm_rs_rate_init(mvm, sta, info->band, false);
                return;
        }
        lq_sta->last_tx = jiffies;

        /* Ignore this Tx frame response if its initial rate doesn't match
         * that of latest Link Quality command.  There may be stragglers
         * from a previous Link Quality command, but we're no longer interested
         * in those; they're either from the "active" mode while we're trying
         * to check "search" mode, or a prior "search" mode after we've moved
         * to a new "search" mode (which might become the new "active" mode).
         */
        table = &lq_sta->lq;
        lq_hwrate = le32_to_cpu(table->rs_table[0]);
        rs_rate_from_ucode_rate(lq_hwrate, info->band, &lq_rate);

        /* Here we actually compare this rate to the latest LQ command */
        if (!rs_rate_equal(&tx_resp_rate, &lq_rate, allow_ant_mismatch)) {
                IWL_DEBUG_RATE(mvm,
                               "initial tx resp rate 0x%x does not match 0x%x\n",
                               tx_resp_hwrate, lq_hwrate);

                /*
                 * Since rates mis-match, the last LQ command may have failed.
                 * After IWL_MISSED_RATE_MAX mis-matches, resync the uCode with
                 * ... driver.
                 */
                lq_sta->missed_rate_counter++;
                if (lq_sta->missed_rate_counter > IWL_MVM_RS_MISSED_RATE_MAX) {
                        lq_sta->missed_rate_counter = 0;
                        IWL_DEBUG_RATE(mvm,
                                       "Too many rates mismatch. Send sync LQ. rs_state %d\n",
                                       lq_sta->rs_state);
                        iwl_mvm_send_lq_cmd(mvm, &lq_sta->lq, false);
                }
                /* Regardless, ignore this status info for outdated rate */
                return;
        } else
                /* Rate did match, so reset the missed_rate_counter */
                lq_sta->missed_rate_counter = 0;

        if (!lq_sta->search_better_tbl) {
                curr_tbl = &(lq_sta->lq_info[lq_sta->active_tbl]);
                other_tbl = &(lq_sta->lq_info[1 - lq_sta->active_tbl]);
        } else {
                curr_tbl = &(lq_sta->lq_info[1 - lq_sta->active_tbl]);
                other_tbl = &(lq_sta->lq_info[lq_sta->active_tbl]);
        }

        if (WARN_ON_ONCE(!rs_rate_column_match(&lq_rate, &curr_tbl->rate))) {
                IWL_DEBUG_RATE(mvm,
                               "Neither active nor search matches tx rate\n");
                tmp_tbl = &(lq_sta->lq_info[lq_sta->active_tbl]);
                rs_dump_rate(mvm, &tmp_tbl->rate, "ACTIVE");
                tmp_tbl = &(lq_sta->lq_info[1 - lq_sta->active_tbl]);
                rs_dump_rate(mvm, &tmp_tbl->rate, "SEARCH");
                rs_dump_rate(mvm, &lq_rate, "ACTUAL");

                /*
                 * no matching table found, let's by-pass the data collection
                 * and continue to perform rate scale to find the rate table
                 */
                rs_stay_in_table(lq_sta, true);
                goto done;
        }

        /*
         * Updating the frame history depends on whether packets were
         * aggregated.
         *
         * For aggregation, all packets were transmitted at the same rate, the
         * first index into rate scale table.
         */
        if (info->flags & IEEE80211_TX_STAT_AMPDU) {
                rs_collect_tpc_data(mvm, lq_sta, curr_tbl, lq_rate.index,
                                    info->status.ampdu_len,
                                    info->status.ampdu_ack_len,
                                    reduced_txp);

                /* ampdu_ack_len = 0 marks no BA was received. For TLC, treat
                 * it as a single frame loss as we don't want the success ratio
                 * to dip too quickly because a BA wasn't received.
                 * For TPC, there's no need for this optimisation since we want
                 * to recover very quickly from a bad power reduction and,
                 * therefore we'd like the success ratio to get an immediate hit
                 * when failing to get a BA, so we'd switch back to a lower or
                 * zero power reduction. When FW transmits agg with a rate
                 * different from the initial rate, it will not use reduced txp
                 * and will send BA notification twice (one empty with reduced
                 * txp equal to the value from LQ and one with reduced txp 0).
                 * We need to update counters for each txp level accordingly.
                 */
                if (info->status.ampdu_ack_len == 0)
                        info->status.ampdu_len = 1;

                rs_collect_tlc_data(mvm, lq_sta, curr_tbl, lq_rate.index,
                                    info->status.ampdu_len,
                                    info->status.ampdu_ack_len);

                /* Update success/fail counts if not searching for new mode */
                if (lq_sta->rs_state == RS_STATE_STAY_IN_COLUMN) {
                        lq_sta->total_success += info->status.ampdu_ack_len;
                        lq_sta->total_failed += (info->status.ampdu_len -
                                        info->status.ampdu_ack_len);
                }
        } else {
                /* For legacy, update frame history with for each Tx retry. */
                retries = info->status.rates[0].count - 1;
                /* HW doesn't send more than 15 retries */
                retries = min(retries, 15);

                /* The last transmission may have been successful */
                legacy_success = !!(info->flags & IEEE80211_TX_STAT_ACK);
                /* Collect data for each rate used during failed TX attempts */
                for (i = 0; i <= retries; ++i) {
                        lq_hwrate = le32_to_cpu(table->rs_table[i]);
                        rs_rate_from_ucode_rate(lq_hwrate, info->band,
                                                &lq_rate);
                        /*
                         * Only collect stats if retried rate is in the same RS
                         * table as active/search.
                         */
                        if (rs_rate_column_match(&lq_rate, &curr_tbl->rate))
                                tmp_tbl = curr_tbl;
                        else if (rs_rate_column_match(&lq_rate,
                                                      &other_tbl->rate))
                                tmp_tbl = other_tbl;
                        else
                                continue;

                        rs_collect_tpc_data(mvm, lq_sta, tmp_tbl,
                                            lq_rate.index, 1,
                                            i < retries ? 0 : legacy_success,
                                            reduced_txp);
                        rs_collect_tlc_data(mvm, lq_sta, tmp_tbl,
                                            lq_rate.index, 1,
                                            i < retries ? 0 : legacy_success);
                }

                /* Update success/fail counts if not searching for new mode */
                if (lq_sta->rs_state == RS_STATE_STAY_IN_COLUMN) {
                        lq_sta->total_success += legacy_success;
                        lq_sta->total_failed += retries + (1 - legacy_success);
                }
        }
        /* The last TX rate is cached in lq_sta; it's set in if/else above */
        lq_sta->last_rate_n_flags = lq_hwrate;
        IWL_DEBUG_RATE(mvm, "reduced txpower: %d\n", reduced_txp);
done:
        /* See if there's a better rate or modulation mode to try. */
        if (sta->supp_rates[info->band])
                rs_rate_scale_perform(mvm, sta, lq_sta, tid, ndp);
}

/*
 * mac80211 sends us Tx status
 */
static void rs_mac80211_tx_status(void *mvm_r,
                                  struct ieee80211_supported_band *sband,
                                  struct ieee80211_sta *sta, void *priv_sta,
                                  struct sk_buff *skb)
{
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
        struct iwl_op_mode *op_mode = (struct iwl_op_mode *)mvm_r;
        struct iwl_mvm *mvm = IWL_OP_MODE_GET_MVM(op_mode);
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);

        if (!iwl_mvm_sta_from_mac80211(sta)->vif)
                return;

        if (!ieee80211_is_data(hdr->frame_control) ||
            info->flags & IEEE80211_TX_CTL_NO_ACK)
                return;

        iwl_mvm_rs_tx_status(mvm, sta, rs_get_tid(hdr), info,
                             ieee80211_is_qos_nullfunc(hdr->frame_control));
}

/*
 * Begin a period of staying with a selected modulation mode.
 * Set "stay_in_tbl" flag to prevent any mode switches.
 * Set frame tx success limits according to legacy vs. high-throughput,
 * and reset overall (spanning all rates) tx success history statistics.
 * These control how long we stay using same modulation mode before
 * searching for a new mode.
 */
static void rs_set_stay_in_table(struct iwl_mvm *mvm, u8 is_legacy,
                                 struct iwl_lq_sta *lq_sta)
{
        IWL_DEBUG_RATE(mvm, "Moving to RS_STATE_STAY_IN_COLUMN\n");
        lq_sta->rs_state = RS_STATE_STAY_IN_COLUMN;
        if (is_legacy) {
                lq_sta->table_count_limit = IWL_MVM_RS_LEGACY_TABLE_COUNT;
                lq_sta->max_failure_limit = IWL_MVM_RS_LEGACY_FAILURE_LIMIT;
                lq_sta->max_success_limit = IWL_MVM_RS_LEGACY_SUCCESS_LIMIT;
        } else {
                lq_sta->table_count_limit = IWL_MVM_RS_NON_LEGACY_TABLE_COUNT;
                lq_sta->max_failure_limit = IWL_MVM_RS_NON_LEGACY_FAILURE_LIMIT;
                lq_sta->max_success_limit = IWL_MVM_RS_NON_LEGACY_SUCCESS_LIMIT;
        }
        lq_sta->table_count = 0;
        lq_sta->total_failed = 0;
        lq_sta->total_success = 0;
        lq_sta->flush_timer = jiffies;
        lq_sta->visited_columns = 0;
}

static inline int rs_get_max_rate_from_mask(unsigned long rate_mask)
{
        if (rate_mask)
                return find_last_bit(&rate_mask, BITS_PER_LONG);
        return IWL_RATE_INVALID;
}

static int rs_get_max_allowed_rate(struct iwl_lq_sta *lq_sta,
                                   const struct rs_tx_column *column)
{
        switch (column->mode) {
        case RS_LEGACY:
                return lq_sta->max_legacy_rate_idx;
        case RS_SISO:
                return lq_sta->max_siso_rate_idx;
        case RS_MIMO2:
                return lq_sta->max_mimo2_rate_idx;
        default:
                WARN_ON_ONCE(1);
        }

        return lq_sta->max_legacy_rate_idx;
}

static const u16 *rs_get_expected_tpt_table(struct iwl_lq_sta *lq_sta,
                                            const struct rs_tx_column *column,
                                            u32 bw)
{
        /* Used to choose among HT tables */
        const u16 (*ht_tbl_pointer)[IWL_RATE_COUNT];

        if (WARN_ON_ONCE(column->mode != RS_LEGACY &&
                         column->mode != RS_SISO &&
                         column->mode != RS_MIMO2))
                return expected_tpt_legacy;

        /* Legacy rates have only one table */
        if (column->mode == RS_LEGACY)
                return expected_tpt_legacy;

        ht_tbl_pointer = expected_tpt_mimo2_20MHz;
        /* Choose among many HT tables depending on number of streams
         * (SISO/MIMO2), channel width (20/40/80), SGI, and aggregation
         * status */
        if (column->mode == RS_SISO) {
                switch (bw) {
                case RATE_MCS_CHAN_WIDTH_20:
                        ht_tbl_pointer = expected_tpt_siso_20MHz;
                        break;
                case RATE_MCS_CHAN_WIDTH_40:
                        ht_tbl_pointer = expected_tpt_siso_40MHz;
                        break;
                case RATE_MCS_CHAN_WIDTH_80:
                        ht_tbl_pointer = expected_tpt_siso_80MHz;
                        break;
                case RATE_MCS_CHAN_WIDTH_160:
                        ht_tbl_pointer = expected_tpt_siso_160MHz;
                        break;
                default:
                        WARN_ON_ONCE(1);
                }
        } else if (column->mode == RS_MIMO2) {
                switch (bw) {
                case RATE_MCS_CHAN_WIDTH_20:
                        ht_tbl_pointer = expected_tpt_mimo2_20MHz;
                        break;
                case RATE_MCS_CHAN_WIDTH_40:
                        ht_tbl_pointer = expected_tpt_mimo2_40MHz;
                        break;
                case RATE_MCS_CHAN_WIDTH_80:
                        ht_tbl_pointer = expected_tpt_mimo2_80MHz;
                        break;
                case RATE_MCS_CHAN_WIDTH_160:
                        ht_tbl_pointer = expected_tpt_mimo2_160MHz;
                        break;
                default:
                        WARN_ON_ONCE(1);
                }
        } else {
                WARN_ON_ONCE(1);
        }

        if (!column->sgi && !lq_sta->is_agg)            /* Normal */
                return ht_tbl_pointer[0];
        else if (column->sgi && !lq_sta->is_agg)        /* SGI */
                return ht_tbl_pointer[1];
        else if (!column->sgi && lq_sta->is_agg)        /* AGG */
                return ht_tbl_pointer[2];
        else                                            /* AGG+SGI */
                return ht_tbl_pointer[3];
}

static void rs_set_expected_tpt_table(struct iwl_lq_sta *lq_sta,
                                      struct iwl_scale_tbl_info *tbl)
{
        struct rs_rate *rate = &tbl->rate;
        const struct rs_tx_column *column = &rs_tx_columns[tbl->column];

        tbl->expected_tpt = rs_get_expected_tpt_table(lq_sta, column, rate->bw);
}

static s32 rs_get_best_rate(struct iwl_mvm *mvm,
                            struct iwl_lq_sta *lq_sta,
                            struct iwl_scale_tbl_info *tbl,     /* "search" */
                            unsigned long rate_mask, s8 index)
{
        struct iwl_scale_tbl_info *active_tbl =
            &(lq_sta->lq_info[lq_sta->active_tbl]);
        s32 success_ratio = active_tbl->win[index].success_ratio;
        u16 expected_current_tpt = active_tbl->expected_tpt[index];
        const u16 *tpt_tbl = tbl->expected_tpt;
        u16 high_low;
        u32 target_tpt;
        int rate_idx;

        if (success_ratio >= RS_PERCENT(IWL_MVM_RS_SR_NO_DECREASE)) {
                target_tpt = 100 * expected_current_tpt;
                IWL_DEBUG_RATE(mvm,
                               "SR %d high. Find rate exceeding EXPECTED_CURRENT %d\n",
                               success_ratio, target_tpt);
        } else {
                target_tpt = lq_sta->last_tpt;
                IWL_DEBUG_RATE(mvm,
                               "SR %d not that good. Find rate exceeding ACTUAL_TPT %d\n",
                               success_ratio, target_tpt);
        }

        rate_idx = find_first_bit(&rate_mask, BITS_PER_LONG);

        while (rate_idx != IWL_RATE_INVALID) {
                if (target_tpt < (100 * tpt_tbl[rate_idx]))
                        break;

                high_low = rs_get_adjacent_rate(mvm, rate_idx, rate_mask,
                                                tbl->rate.type);

                rate_idx = (high_low >> 8) & 0xff;
        }

        IWL_DEBUG_RATE(mvm, "Best rate found %d target_tp %d expected_new %d\n",
                       rate_idx, target_tpt,
                       rate_idx != IWL_RATE_INVALID ?
                       100 * tpt_tbl[rate_idx] : IWL_INVALID_VALUE);

        return rate_idx;
}

static u32 rs_bw_from_sta_bw(struct ieee80211_sta *sta)
{
        switch (sta->bandwidth) {
        case IEEE80211_STA_RX_BW_160:
                return RATE_MCS_CHAN_WIDTH_160;
        case IEEE80211_STA_RX_BW_80:
                return RATE_MCS_CHAN_WIDTH_80;
        case IEEE80211_STA_RX_BW_40:
                return RATE_MCS_CHAN_WIDTH_40;
        case IEEE80211_STA_RX_BW_20:
        default:
                return RATE_MCS_CHAN_WIDTH_20;
        }
}

/*
 * Check whether we should continue using same modulation mode, or
 * begin search for a new mode, based on:
 * 1) # tx successes or failures while using this mode
 * 2) # times calling this function
 * 3) elapsed time in this mode (not used, for now)
 */
static void rs_stay_in_table(struct iwl_lq_sta *lq_sta, bool force_search)
{
        struct iwl_scale_tbl_info *tbl;
        int active_tbl;
        int flush_interval_passed = 0;
        struct iwl_mvm *mvm;

        mvm = lq_sta->pers.drv;
        active_tbl = lq_sta->active_tbl;

        tbl = &(lq_sta->lq_info[active_tbl]);

        /* If we've been disallowing search, see if we should now allow it */
        if (lq_sta->rs_state == RS_STATE_STAY_IN_COLUMN) {
                /* Elapsed time using current modulation mode */
                if (lq_sta->flush_timer)
                        flush_interval_passed =
                                time_after(jiffies,
                                           (unsigned long)(lq_sta->flush_timer +
                                                           (IWL_MVM_RS_STAY_IN_COLUMN_TIMEOUT * HZ)));

                /*
                 * Check if we should allow search for new modulation mode.
                 * If many frames have failed or succeeded, or we've used
                 * this same modulation for a long time, allow search, and
                 * reset history stats that keep track of whether we should
                 * allow a new search.  Also (below) reset all bitmaps and
                 * stats in active history.
                 */
                if (force_search ||
                    (lq_sta->total_failed > lq_sta->max_failure_limit) ||
                    (lq_sta->total_success > lq_sta->max_success_limit) ||
                    ((!lq_sta->search_better_tbl) &&
                     (lq_sta->flush_timer) && (flush_interval_passed))) {
                        IWL_DEBUG_RATE(mvm,
                                       "LQ: stay is expired %d %d %d\n",
                                     lq_sta->total_failed,
                                     lq_sta->total_success,
                                     flush_interval_passed);

                        /* Allow search for new mode */
                        lq_sta->rs_state = RS_STATE_SEARCH_CYCLE_STARTED;
                        IWL_DEBUG_RATE(mvm,
                                       "Moving to RS_STATE_SEARCH_CYCLE_STARTED\n");
                        lq_sta->total_failed = 0;
                        lq_sta->total_success = 0;
                        lq_sta->flush_timer = 0;
                        /* mark the current column as visited */
                        lq_sta->visited_columns = BIT(tbl->column);
                /*
                 * Else if we've used this modulation mode enough repetitions
                 * (regardless of elapsed time or success/failure), reset
                 * history bitmaps and rate-specific stats for all rates in
                 * active table.
                 */
                } else {
                        lq_sta->table_count++;
                        if (lq_sta->table_count >=
                            lq_sta->table_count_limit) {
                                lq_sta->table_count = 0;

                                IWL_DEBUG_RATE(mvm,
                                               "LQ: stay in table clear win\n");
                                rs_rate_scale_clear_tbl_windows(mvm, tbl);
                        }
                }

                /* If transitioning to allow "search", reset all history
                 * bitmaps and stats in active table (this will become the new
                 * "search" table). */
                if (lq_sta->rs_state == RS_STATE_SEARCH_CYCLE_STARTED) {
                        rs_rate_scale_clear_tbl_windows(mvm, tbl);
                }
        }
}

static void rs_set_amsdu_len(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
                             struct iwl_scale_tbl_info *tbl,
                             enum rs_action scale_action)
{
        struct iwl_mvm_sta *sta_priv = iwl_mvm_sta_from_mac80211(sta);

        if ((!is_vht(&tbl->rate) && !is_ht(&tbl->rate)) ||
            tbl->rate.index < IWL_RATE_MCS_5_INDEX ||
            scale_action == RS_ACTION_DOWNSCALE)
                sta_priv->tlc_amsdu = false;
        else
                sta_priv->tlc_amsdu = true;
}

/*
 * setup rate table in uCode
 */
static void rs_update_rate_tbl(struct iwl_mvm *mvm,
                               struct ieee80211_sta *sta,
                               struct iwl_lq_sta *lq_sta,
                               struct iwl_scale_tbl_info *tbl)
{
        rs_fill_lq_cmd(mvm, sta, lq_sta, &tbl->rate);
        iwl_mvm_send_lq_cmd(mvm, &lq_sta->lq, false);
}

static bool rs_tweak_rate_tbl(struct iwl_mvm *mvm,
                              struct ieee80211_sta *sta,
                              struct iwl_lq_sta *lq_sta,
                              struct iwl_scale_tbl_info *tbl,
                              enum rs_action scale_action)
{
        if (sta->bandwidth != IEEE80211_STA_RX_BW_80)
                return false;

        if (!is_vht_siso(&tbl->rate))
                return false;

        if ((tbl->rate.bw == RATE_MCS_CHAN_WIDTH_80) &&
            (tbl->rate.index == IWL_RATE_MCS_0_INDEX) &&
            (scale_action == RS_ACTION_DOWNSCALE)) {
                tbl->rate.bw = RATE_MCS_CHAN_WIDTH_20;
                tbl->rate.index = IWL_RATE_MCS_4_INDEX;
                IWL_DEBUG_RATE(mvm, "Switch 80Mhz SISO MCS0 -> 20Mhz MCS4\n");
                goto tweaked;
        }

        /* Go back to 80Mhz MCS1 only if we've established that 20Mhz MCS5 is
         * sustainable, i.e. we're past the test window. We can't go back
         * if MCS5 is just tested as this will happen always after switching
         * to 20Mhz MCS4 because the rate stats are cleared.
         */
        if ((tbl->rate.bw == RATE_MCS_CHAN_WIDTH_20) &&
            (((tbl->rate.index == IWL_RATE_MCS_5_INDEX) &&
             (scale_action == RS_ACTION_STAY)) ||
             ((tbl->rate.index > IWL_RATE_MCS_5_INDEX) &&
              (scale_action == RS_ACTION_UPSCALE)))) {
                tbl->rate.bw = RATE_MCS_CHAN_WIDTH_80;
                tbl->rate.index = IWL_RATE_MCS_1_INDEX;
                IWL_DEBUG_RATE(mvm, "Switch 20Mhz SISO MCS5 -> 80Mhz MCS1\n");
                goto tweaked;
        }

        return false;

tweaked:
        rs_set_expected_tpt_table(lq_sta, tbl);
        rs_rate_scale_clear_tbl_windows(mvm, tbl);
        return true;
}

static enum rs_column rs_get_next_column(struct iwl_mvm *mvm,
                                         struct iwl_lq_sta *lq_sta,
                                         struct ieee80211_sta *sta,
                                         struct iwl_scale_tbl_info *tbl)
{
        int i, j, max_rate;
        enum rs_column next_col_id;
        const struct rs_tx_column *curr_col = &rs_tx_columns[tbl->column];
        const struct rs_tx_column *next_col;
        allow_column_func_t allow_func;
        u8 valid_ants = iwl_mvm_get_valid_tx_ant(mvm);
        const u16 *expected_tpt_tbl;
        u16 tpt, max_expected_tpt;

        for (i = 0; i < MAX_NEXT_COLUMNS; i++) {
                next_col_id = curr_col->next_columns[i];

                if (next_col_id == RS_COLUMN_INVALID)
                        continue;

                if (lq_sta->visited_columns & BIT(next_col_id)) {
                        IWL_DEBUG_RATE(mvm, "Skip already visited column %d\n",
                                       next_col_id);
                        continue;
                }

                next_col = &rs_tx_columns[next_col_id];

                if (!rs_is_valid_ant(valid_ants, next_col->ant)) {
                        IWL_DEBUG_RATE(mvm,
                                       "Skip column %d as ANT config isn't supported by chip. valid_ants 0x%x column ant 0x%x\n",
                                       next_col_id, valid_ants, next_col->ant);
                        continue;
                }

                for (j = 0; j < MAX_COLUMN_CHECKS; j++) {
                        allow_func = next_col->checks[j];
                        if (allow_func && !allow_func(mvm, sta, &tbl->rate,
                                                      next_col))
                                break;
                }

                if (j != MAX_COLUMN_CHECKS) {
                        IWL_DEBUG_RATE(mvm,
                                       "Skip column %d: not allowed (check %d failed)\n",
                                       next_col_id, j);

                        continue;
                }

                tpt = lq_sta->last_tpt / 100;
                expected_tpt_tbl = rs_get_expected_tpt_table(lq_sta, next_col,
                                                     rs_bw_from_sta_bw(sta));
                if (WARN_ON_ONCE(!expected_tpt_tbl))
                        continue;

                max_rate = rs_get_max_allowed_rate(lq_sta, next_col);
                if (max_rate == IWL_RATE_INVALID) {
                        IWL_DEBUG_RATE(mvm,
                                       "Skip column %d: no rate is allowed in this column\n",
                                       next_col_id);
                        continue;
                }

                max_expected_tpt = expected_tpt_tbl[max_rate];
                if (tpt >= max_expected_tpt) {
                        IWL_DEBUG_RATE(mvm,
                                       "Skip column %d: can't beat current TPT. Max expected %d current %d\n",
                                       next_col_id, max_expected_tpt, tpt);
                        continue;
                }

                IWL_DEBUG_RATE(mvm,
                               "Found potential column %d. Max expected %d current %d\n",
                               next_col_id, max_expected_tpt, tpt);
                break;
        }

        if (i == MAX_NEXT_COLUMNS)
                return RS_COLUMN_INVALID;

        return next_col_id;
}

static int rs_switch_to_column(struct iwl_mvm *mvm,
                               struct iwl_lq_sta *lq_sta,
                               struct ieee80211_sta *sta,
                               enum rs_column col_id)
{
        struct iwl_scale_tbl_info *tbl = &(lq_sta->lq_info[lq_sta->active_tbl]);
        struct iwl_scale_tbl_info *search_tbl =
                                &(lq_sta->lq_info[(1 - lq_sta->active_tbl)]);
        struct rs_rate *rate = &search_tbl->rate;
        const struct rs_tx_column *column = &rs_tx_columns[col_id];
        const struct rs_tx_column *curr_column = &rs_tx_columns[tbl->column];
        u32 sz = (sizeof(struct iwl_scale_tbl_info) -
                  (sizeof(struct iwl_rate_scale_data) * IWL_RATE_COUNT));
        unsigned long rate_mask = 0;
        u32 rate_idx = 0;

        memcpy(search_tbl, tbl, sz);

        rate->sgi = column->sgi;
        rate->ant = column->ant;

        if (column->mode == RS_LEGACY) {
                if (lq_sta->band == NL80211_BAND_5GHZ)
                        rate->type = LQ_LEGACY_A;
                else
                        rate->type = LQ_LEGACY_G;

                rate->bw = RATE_MCS_CHAN_WIDTH_20;
                rate->ldpc = false;
                rate_mask = lq_sta->active_legacy_rate;
        } else if (column->mode == RS_SISO) {
                rate->type = lq_sta->is_vht ? LQ_VHT_SISO : LQ_HT_SISO;
                rate_mask = lq_sta->active_siso_rate;
        } else if (column->mode == RS_MIMO2) {
                rate->type = lq_sta->is_vht ? LQ_VHT_MIMO2 : LQ_HT_MIMO2;
                rate_mask = lq_sta->active_mimo2_rate;
        } else {
                WARN_ONCE(1, "Bad column mode");
        }

        if (column->mode != RS_LEGACY) {
                rate->bw = rs_bw_from_sta_bw(sta);
                rate->ldpc = lq_sta->ldpc;
        }

        search_tbl->column = col_id;
        rs_set_expected_tpt_table(lq_sta, search_tbl);

        lq_sta->visited_columns |= BIT(col_id);

        /* Get the best matching rate if we're changing modes. e.g.
         * SISO->MIMO, LEGACY->SISO, MIMO->SISO
         */
        if (curr_column->mode != column->mode) {
                rate_idx = rs_get_best_rate(mvm, lq_sta, search_tbl,
                                            rate_mask, rate->index);

                if ((rate_idx == IWL_RATE_INVALID) ||
                    !(BIT(rate_idx) & rate_mask)) {
                        IWL_DEBUG_RATE(mvm,
                                       "can not switch with index %d"
                                       " rate mask %lx\n",
                                       rate_idx, rate_mask);

                        goto err;
                }

                rate->index = rate_idx;
        }

        IWL_DEBUG_RATE(mvm, "Switched to column %d: Index %d\n",
                       col_id, rate->index);

        return 0;

err:
        rate->type = LQ_NONE;
        return -1;
}

static enum rs_action rs_get_rate_action(struct iwl_mvm *mvm,
                                         struct iwl_scale_tbl_info *tbl,
                                         s32 sr, int low, int high,
                                         int current_tpt,
                                         int low_tpt, int high_tpt)
{
        enum rs_action action = RS_ACTION_STAY;

        if ((sr <= RS_PERCENT(IWL_MVM_RS_SR_FORCE_DECREASE)) ||
            (current_tpt == 0)) {
                IWL_DEBUG_RATE(mvm,
                               "Decrease rate because of low SR\n");
                return RS_ACTION_DOWNSCALE;
        }

        if ((low_tpt == IWL_INVALID_VALUE) &&
            (high_tpt == IWL_INVALID_VALUE) &&
            (high != IWL_RATE_INVALID)) {
                IWL_DEBUG_RATE(mvm,
                               "No data about high/low rates. Increase rate\n");
                return RS_ACTION_UPSCALE;
        }

        if ((high_tpt == IWL_INVALID_VALUE) &&
            (high != IWL_RATE_INVALID) &&
            (low_tpt != IWL_INVALID_VALUE) &&
            (low_tpt < current_tpt)) {
                IWL_DEBUG_RATE(mvm,
                               "No data about high rate and low rate is worse. Increase rate\n");
                return RS_ACTION_UPSCALE;
        }

        if ((high_tpt != IWL_INVALID_VALUE) &&
            (high_tpt > current_tpt)) {
                IWL_DEBUG_RATE(mvm,
                               "Higher rate is better. Increate rate\n");
                return RS_ACTION_UPSCALE;
        }

        if ((low_tpt != IWL_INVALID_VALUE) &&
            (high_tpt != IWL_INVALID_VALUE) &&
            (low_tpt < current_tpt) &&
            (high_tpt < current_tpt)) {
                IWL_DEBUG_RATE(mvm,
                               "Both high and low are worse. Maintain rate\n");
                return RS_ACTION_STAY;
        }

        if ((low_tpt != IWL_INVALID_VALUE) &&
            (low_tpt > current_tpt)) {
                IWL_DEBUG_RATE(mvm,
                               "Lower rate is better\n");
                action = RS_ACTION_DOWNSCALE;
                goto out;
        }

        if ((low_tpt == IWL_INVALID_VALUE) &&
            (low != IWL_RATE_INVALID)) {
                IWL_DEBUG_RATE(mvm,
                               "No data about lower rate\n");
                action = RS_ACTION_DOWNSCALE;
                goto out;

        }

        IWL_DEBUG_RATE(mvm, "Maintain rate\n");

out:
        if ((action == RS_ACTION_DOWNSCALE) && (low != IWL_RATE_INVALID)) {
                if (sr >= RS_PERCENT(IWL_MVM_RS_SR_NO_DECREASE)) {
                        IWL_DEBUG_RATE(mvm,
                                       "SR is above NO DECREASE. Avoid downscale\n");
                        action = RS_ACTION_STAY;
                } else if (current_tpt > (100 * tbl->expected_tpt[low])) {
                        IWL_DEBUG_RATE(mvm,
                                       "Current TPT is higher than max expected in low rate. Avoid downscale\n");
                        action = RS_ACTION_STAY;
                } else {
                        IWL_DEBUG_RATE(mvm, "Decrease rate\n");
                }
        }

        return action;
}

static bool rs_stbc_allow(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
                          struct iwl_lq_sta *lq_sta)
{
        /* Our chip supports Tx STBC and the peer is an HT/VHT STA which
         * supports STBC of at least 1*SS
         */
        if (!lq_sta->stbc_capable)
                return false;

        if (!iwl_mvm_bt_coex_is_mimo_allowed(mvm, sta))
                return false;

        return true;
}

static void rs_get_adjacent_txp(struct iwl_mvm *mvm, int index,
                                int *weaker, int *stronger)
{
        *weaker = index + IWL_MVM_RS_TPC_TX_POWER_STEP;
        if (*weaker > TPC_MAX_REDUCTION)
                *weaker = TPC_INVALID;

        *stronger = index - IWL_MVM_RS_TPC_TX_POWER_STEP;
        if (*stronger < 0)
                *stronger = TPC_INVALID;
}

static bool rs_tpc_allowed(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
                           struct rs_rate *rate, enum nl80211_band band)
{
        int index = rate->index;
        bool cam = (iwlmvm_mod_params.power_scheme == IWL_POWER_SCHEME_CAM);
        bool sta_ps_disabled = (vif->type == NL80211_IFTYPE_STATION &&
                                !vif->bss_conf.ps);

        IWL_DEBUG_RATE(mvm, "cam: %d sta_ps_disabled %d\n",
                       cam, sta_ps_disabled);
        /*
         * allow tpc only if power management is enabled, or bt coex
         * activity grade allows it and we are on 2.4Ghz.
         */
        if ((cam || sta_ps_disabled) &&
            !iwl_mvm_bt_coex_is_tpc_allowed(mvm, band))
                return false;

        IWL_DEBUG_RATE(mvm, "check rate, table type: %d\n", rate->type);
        if (is_legacy(rate))
                return index == IWL_RATE_54M_INDEX;
        if (is_ht(rate))
                return index == IWL_RATE_MCS_7_INDEX;
        if (is_vht(rate))
                return index == IWL_RATE_MCS_7_INDEX ||
                       index == IWL_RATE_MCS_8_INDEX ||
                       index == IWL_RATE_MCS_9_INDEX;

        WARN_ON_ONCE(1);
        return false;
}

enum tpc_action {
        TPC_ACTION_STAY,
        TPC_ACTION_DECREASE,
        TPC_ACTION_INCREASE,
        TPC_ACTION_NO_RESTIRCTION,
};

static enum tpc_action rs_get_tpc_action(struct iwl_mvm *mvm,
                                         s32 sr, int weak, int strong,
                                         int current_tpt,
                                         int weak_tpt, int strong_tpt)
{
        /* stay until we have valid tpt */
        if (current_tpt == IWL_INVALID_VALUE) {
                IWL_DEBUG_RATE(mvm, "no current tpt. stay.\n");
                return TPC_ACTION_STAY;
        }

        /* Too many failures, increase txp */
        if (sr <= RS_PERCENT(IWL_MVM_RS_TPC_SR_FORCE_INCREASE) ||
            current_tpt == 0) {
                IWL_DEBUG_RATE(mvm, "increase txp because of weak SR\n");
                return TPC_ACTION_NO_RESTIRCTION;
        }

        /* try decreasing first if applicable */
        if (sr >= RS_PERCENT(IWL_MVM_RS_TPC_SR_NO_INCREASE) &&
            weak != TPC_INVALID) {
                if (weak_tpt == IWL_INVALID_VALUE &&
                    (strong_tpt == IWL_INVALID_VALUE ||
                     current_tpt >= strong_tpt)) {
                        IWL_DEBUG_RATE(mvm,
                                       "no weak txp measurement. decrease txp\n");
                        return TPC_ACTION_DECREASE;
                }

                if (weak_tpt > current_tpt) {
                        IWL_DEBUG_RATE(mvm,
                                       "lower txp has better tpt. decrease txp\n");
                        return TPC_ACTION_DECREASE;
                }
        }

        /* next, increase if needed */
        if (sr < RS_PERCENT(IWL_MVM_RS_TPC_SR_NO_INCREASE) &&
            strong != TPC_INVALID) {
                if (weak_tpt == IWL_INVALID_VALUE &&
                    strong_tpt != IWL_INVALID_VALUE &&
                    current_tpt < strong_tpt) {
                        IWL_DEBUG_RATE(mvm,
                                       "higher txp has better tpt. increase txp\n");
                        return TPC_ACTION_INCREASE;
                }

                if (weak_tpt < current_tpt &&
                    (strong_tpt == IWL_INVALID_VALUE ||
                     strong_tpt > current_tpt)) {
                        IWL_DEBUG_RATE(mvm,
                                       "lower txp has worse tpt. increase txp\n");
                        return TPC_ACTION_INCREASE;
                }
        }

        IWL_DEBUG_RATE(mvm, "no need to increase or decrease txp - stay\n");
        return TPC_ACTION_STAY;
}

static bool rs_tpc_perform(struct iwl_mvm *mvm,
                           struct ieee80211_sta *sta,
                           struct iwl_lq_sta *lq_sta,
                           struct iwl_scale_tbl_info *tbl)
{
        struct iwl_mvm_sta *mvm_sta = iwl_mvm_sta_from_mac80211(sta);
        struct ieee80211_vif *vif = mvm_sta->vif;
        struct ieee80211_chanctx_conf *chanctx_conf;
        enum nl80211_band band;
        struct iwl_rate_scale_data *window;
        struct rs_rate *rate = &tbl->rate;
        enum tpc_action action;
        s32 sr;
        u8 cur = lq_sta->lq.reduced_tpc;
        int current_tpt;
        int weak, strong;
        int weak_tpt = IWL_INVALID_VALUE, strong_tpt = IWL_INVALID_VALUE;

#ifdef CONFIG_MAC80211_DEBUGFS
        if (lq_sta->pers.dbg_fixed_txp_reduction <= TPC_MAX_REDUCTION) {
                IWL_DEBUG_RATE(mvm, "fixed tpc: %d\n",
                               lq_sta->pers.dbg_fixed_txp_reduction);
                lq_sta->lq.reduced_tpc = lq_sta->pers.dbg_fixed_txp_reduction;
                return cur != lq_sta->pers.dbg_fixed_txp_reduction;
        }
#endif

        rcu_read_lock();
        chanctx_conf = rcu_dereference(vif->chanctx_conf);
        if (WARN_ON(!chanctx_conf))
                band = NUM_NL80211_BANDS;
        else
                band = chanctx_conf->def.chan->band;
        rcu_read_unlock();

        if (!rs_tpc_allowed(mvm, vif, rate, band)) {
                IWL_DEBUG_RATE(mvm,
                               "tpc is not allowed. remove txp restrictions\n");
                lq_sta->lq.reduced_tpc = TPC_NO_REDUCTION;
                return cur != TPC_NO_REDUCTION;
        }

        rs_get_adjacent_txp(mvm, cur, &weak, &strong);

        /* Collect measured throughputs for current and adjacent rates */
        window = tbl->tpc_win;
        sr = window[cur].success_ratio;
        current_tpt = window[cur].average_tpt;
        if (weak != TPC_INVALID)
                weak_tpt = window[weak].average_tpt;
        if (strong != TPC_INVALID)
                strong_tpt = window[strong].average_tpt;

        IWL_DEBUG_RATE(mvm,
                       "(TPC: %d): cur_tpt %d SR %d weak %d strong %d weak_tpt %d strong_tpt %d\n",
                       cur, current_tpt, sr, weak, strong,
                       weak_tpt, strong_tpt);

        action = rs_get_tpc_action(mvm, sr, weak, strong,
                                   current_tpt, weak_tpt, strong_tpt);

        /* override actions if we are on the edge */
        if (weak == TPC_INVALID && action == TPC_ACTION_DECREASE) {
                IWL_DEBUG_RATE(mvm, "already in lowest txp, stay\n");
                action = TPC_ACTION_STAY;
        } else if (strong == TPC_INVALID &&
                   (action == TPC_ACTION_INCREASE ||
                    action == TPC_ACTION_NO_RESTIRCTION)) {
                IWL_DEBUG_RATE(mvm, "already in highest txp, stay\n");
                action = TPC_ACTION_STAY;
        }

        switch (action) {
        case TPC_ACTION_DECREASE:
                lq_sta->lq.reduced_tpc = weak;
                return true;
        case TPC_ACTION_INCREASE:
                lq_sta->lq.reduced_tpc = strong;
                return true;
        case TPC_ACTION_NO_RESTIRCTION:
                lq_sta->lq.reduced_tpc = TPC_NO_REDUCTION;
                return true;
        case TPC_ACTION_STAY:
                /* do nothing */
                break;
        }
        return false;
}

/*
 * Do rate scaling and search for new modulation mode.
 */
static void rs_rate_scale_perform(struct iwl_mvm *mvm,
                                  struct ieee80211_sta *sta,
                                  struct iwl_lq_sta *lq_sta,
                                  int tid, bool ndp)
{
        int low = IWL_RATE_INVALID;
        int high = IWL_RATE_INVALID;
        int index;
        struct iwl_rate_scale_data *window = NULL;
        int current_tpt = IWL_INVALID_VALUE;
        int low_tpt = IWL_INVALID_VALUE;
        int high_tpt = IWL_INVALID_VALUE;
        u32 fail_count;
        enum rs_action scale_action = RS_ACTION_STAY;
        u16 rate_mask;
        u8 update_lq = 0;
        struct iwl_scale_tbl_info *tbl, *tbl1;
        u8 active_tbl = 0;
        u8 done_search = 0;
        u16 high_low;
        s32 sr;
        u8 prev_agg = lq_sta->is_agg;
        struct iwl_mvm_sta *sta_priv = iwl_mvm_sta_from_mac80211(sta);
        struct iwl_mvm_tid_data *tid_data;
        struct rs_rate *rate;

        lq_sta->is_agg = !!sta_priv->agg_tids;

        /*
         * Select rate-scale / modulation-mode table to work with in
         * the rest of this function:  "search" if searching for better
         * modulation mode, or "active" if doing rate scaling within a mode.
         */
        if (!lq_sta->search_better_tbl)
                active_tbl = lq_sta->active_tbl;
        else
                active_tbl = 1 - lq_sta->active_tbl;

        tbl = &(lq_sta->lq_info[active_tbl]);
        rate = &tbl->rate;

        if (prev_agg != lq_sta->is_agg) {
                IWL_DEBUG_RATE(mvm,
                               "Aggregation changed: prev %d current %d. Update expected TPT table\n",
                               prev_agg, lq_sta->is_agg);
                rs_set_expected_tpt_table(lq_sta, tbl);
                rs_rate_scale_clear_tbl_windows(mvm, tbl);
        }

        /* current tx rate */
        index = rate->index;

        /* rates available for this association, and for modulation mode */
        rate_mask = rs_get_supported_rates(lq_sta, rate);

        if (!(BIT(index) & rate_mask)) {
                IWL_ERR(mvm, "Current Rate is not valid\n");
                if (lq_sta->search_better_tbl) {
                        /* revert to active table if search table is not valid*/
                        rate->type = LQ_NONE;
                        lq_sta->search_better_tbl = 0;
                        tbl = &(lq_sta->lq_info[lq_sta->active_tbl]);
                        rs_update_rate_tbl(mvm, sta, lq_sta, tbl);
                }
                return;
        }

        /* Get expected throughput table and history window for current rate */
        if (!tbl->expected_tpt) {
                IWL_ERR(mvm, "tbl->expected_tpt is NULL\n");
                return;
        }

        /* TODO: handle rate_idx_mask and rate_idx_mcs_mask */
        window = &(tbl->win[index]);

        /*
         * If there is not enough history to calculate actual average
         * throughput, keep analyzing results of more tx frames, without
         * changing rate or mode (bypass most of the rest of this function).
         * Set up new rate table in uCode only if old rate is not supported
         * in current association (use new rate found above).
         */
        fail_count = window->counter - window->success_counter;
        if ((fail_count < IWL_MVM_RS_RATE_MIN_FAILURE_TH) &&
            (window->success_counter < IWL_MVM_RS_RATE_MIN_SUCCESS_TH)) {
                IWL_DEBUG_RATE(mvm,
                               "%s: Test Window: succ %d total %d\n",
                               rs_pretty_rate(rate),
                               window->success_counter, window->counter);

                /* Can't calculate this yet; not enough history */
                window->average_tpt = IWL_INVALID_VALUE;

                /* Should we stay with this modulation mode,
                 * or search for a new one? */
                rs_stay_in_table(lq_sta, false);

                return;
        }

        /* If we are searching for better modulation mode, check success. */
        if (lq_sta->search_better_tbl) {
                /* If good success, continue using the "search" mode;
                 * no need to send new link quality command, since we're
                 * continuing to use the setup that we've been trying. */
                if (window->average_tpt > lq_sta->last_tpt) {
                        IWL_DEBUG_RATE(mvm,
                                       "SWITCHING TO NEW TABLE SR: %d "
                                       "cur-tpt %d old-tpt %d\n",
                                       window->success_ratio,
                                       window->average_tpt,
                                       lq_sta->last_tpt);

                        /* Swap tables; "search" becomes "active" */
                        lq_sta->active_tbl = active_tbl;
                        current_tpt = window->average_tpt;
                /* Else poor success; go back to mode in "active" table */
                } else {
                        IWL_DEBUG_RATE(mvm,
                                       "GOING BACK TO THE OLD TABLE: SR %d "
                                       "cur-tpt %d old-tpt %d\n",
                                       window->success_ratio,
                                       window->average_tpt,
                                       lq_sta->last_tpt);

                        /* Nullify "search" table */
                        rate->type = LQ_NONE;

                        /* Revert to "active" table */
                        active_tbl = lq_sta->active_tbl;
                        tbl = &(lq_sta->lq_info[active_tbl]);

                        /* Revert to "active" rate and throughput info */
                        index = tbl->rate.index;
                        current_tpt = lq_sta->last_tpt;

                        /* Need to set up a new rate table in uCode */
                        update_lq = 1;
                }

                /* Either way, we've made a decision; modulation mode
                 * search is done, allow rate adjustment next time. */
                lq_sta->search_better_tbl = 0;
                done_search = 1;        /* Don't switch modes below! */
                goto lq_update;
        }

        /* (Else) not in search of better modulation mode, try for better
         * starting rate, while staying in this mode. */
        high_low = rs_get_adjacent_rate(mvm, index, rate_mask, rate->type);
        low = high_low & 0xff;
        high = (high_low >> 8) & 0xff;

        /* TODO: handle rate_idx_mask and rate_idx_mcs_mask */

        sr = window->success_ratio;

        /* Collect measured throughputs for current and adjacent rates */
        current_tpt = window->average_tpt;
        if (low != IWL_RATE_INVALID)
                low_tpt = tbl->win[low].average_tpt;
        if (high != IWL_RATE_INVALID)
                high_tpt = tbl->win[high].average_tpt;

        IWL_DEBUG_RATE(mvm,
                       "%s: cur_tpt %d SR %d low %d high %d low_tpt %d high_tpt %d\n",
                       rs_pretty_rate(rate), current_tpt, sr,
                       low, high, low_tpt, high_tpt);

        scale_action = rs_get_rate_action(mvm, tbl, sr, low, high,
                                          current_tpt, low_tpt, high_tpt);

        /* Force a search in case BT doesn't like us being in MIMO */
        if (is_mimo(rate) &&
            !iwl_mvm_bt_coex_is_mimo_allowed(mvm, sta)) {
                IWL_DEBUG_RATE(mvm,
                               "BT Coex forbids MIMO. Search for new config\n");
                rs_stay_in_table(lq_sta, true);
                goto lq_update;
        }

        switch (scale_action) {
        case RS_ACTION_DOWNSCALE:
                /* Decrease starting rate, update uCode's rate table */
                if (low != IWL_RATE_INVALID) {
                        update_lq = 1;
                        index = low;
                } else {
                        IWL_DEBUG_RATE(mvm,
                                       "At the bottom rate. Can't decrease\n");
                }

                break;
        case RS_ACTION_UPSCALE:
                /* Increase starting rate, update uCode's rate table */
                if (high != IWL_RATE_INVALID) {
                        update_lq = 1;
                        index = high;
                } else {
                        IWL_DEBUG_RATE(mvm,
                                       "At the top rate. Can't increase\n");
                }

                break;
        case RS_ACTION_STAY:
                /* No change */
                if (lq_sta->rs_state == RS_STATE_STAY_IN_COLUMN)
                        update_lq = rs_tpc_perform(mvm, sta, lq_sta, tbl);
                break;
        default:
                break;
        }

lq_update:
        /* Replace uCode's rate table for the destination station. */
        if (update_lq) {
                tbl->rate.index = index;
                if (IWL_MVM_RS_80_20_FAR_RANGE_TWEAK)
                        rs_tweak_rate_tbl(mvm, sta, lq_sta, tbl, scale_action);
                rs_set_amsdu_len(mvm, sta, tbl, scale_action);
                rs_update_rate_tbl(mvm, sta, lq_sta, tbl);
        }

        rs_stay_in_table(lq_sta, false);

        /*
         * Search for new modulation mode if we're:
         * 1)  Not changing rates right now
         * 2)  Not just finishing up a search
         * 3)  Allowing a new search
         */
        if (!update_lq && !done_search &&
            lq_sta->rs_state == RS_STATE_SEARCH_CYCLE_STARTED
            && window->counter) {
                enum rs_column next_column;

                /* Save current throughput to compare with "search" throughput*/
                lq_sta->last_tpt = current_tpt;

                IWL_DEBUG_RATE(mvm,
                               "Start Search: update_lq %d done_search %d rs_state %d win->counter %d\n",
                               update_lq, done_search, lq_sta->rs_state,
                               window->counter);

                next_column = rs_get_next_column(mvm, lq_sta, sta, tbl);
                if (next_column != RS_COLUMN_INVALID) {
                        int ret = rs_switch_to_column(mvm, lq_sta, sta,
                                                      next_column);
                        if (!ret)
                                lq_sta->search_better_tbl = 1;
                } else {
                        IWL_DEBUG_RATE(mvm,
                                       "No more columns to explore in search cycle. Go to RS_STATE_SEARCH_CYCLE_ENDED\n");
                        lq_sta->rs_state = RS_STATE_SEARCH_CYCLE_ENDED;
                }

                /* If new "search" mode was selected, set up in uCode table */
                if (lq_sta->search_better_tbl) {
                        /* Access the "search" table, clear its history. */
                        tbl = &(lq_sta->lq_info[(1 - lq_sta->active_tbl)]);
                        rs_rate_scale_clear_tbl_windows(mvm, tbl);

                        /* Use new "search" start rate */
                        index = tbl->rate.index;

                        rs_dump_rate(mvm, &tbl->rate,
                                     "Switch to SEARCH TABLE:");
                        rs_update_rate_tbl(mvm, sta, lq_sta, tbl);
                } else {
                        done_search = 1;
                }
        }

        if (done_search && lq_sta->rs_state == RS_STATE_SEARCH_CYCLE_ENDED) {
                /* If the "active" (non-search) mode was legacy,
                 * and we've tried switching antennas,
                 * but we haven't been able to try HT modes (not available),
                 * stay with best antenna legacy modulation for a while
                 * before next round of mode comparisons. */
                tbl1 = &(lq_sta->lq_info[lq_sta->active_tbl]);
                if (is_legacy(&tbl1->rate)) {
                        IWL_DEBUG_RATE(mvm, "LQ: STAY in legacy table\n");

                        if (tid != IWL_MAX_TID_COUNT) {
                                tid_data = &sta_priv->tid_data[tid];
                                if (tid_data->state != IWL_AGG_OFF) {
                                        IWL_DEBUG_RATE(mvm,
                                                       "Stop aggregation on tid %d\n",
                                                       tid);
                                        ieee80211_stop_tx_ba_session(sta, tid);
                                }
                        }
                        rs_set_stay_in_table(mvm, 1, lq_sta);
                } else {
                /* If we're in an HT mode, and all 3 mode switch actions
                 * have been tried and compared, stay in this best modulation
                 * mode for a while before next round of mode comparisons. */
                        if ((lq_sta->last_tpt > IWL_AGG_TPT_THREHOLD) &&
                            (lq_sta->tx_agg_tid_en & (1 << tid)) &&
                            (tid != IWL_MAX_TID_COUNT)) {
                                tid_data = &sta_priv->tid_data[tid];
                                if (tid_data->state == IWL_AGG_OFF && !ndp) {
                                        IWL_DEBUG_RATE(mvm,
                                                       "try to aggregate tid %d\n",
                                                       tid);
                                        rs_tl_turn_on_agg(mvm, tid,
                                                          lq_sta, sta);
                                }
                        }
                        rs_set_stay_in_table(mvm, 0, lq_sta);
                }
        }
}

struct rs_init_rate_info {
        s8 rssi;
        u8 rate_idx;
};

static const struct rs_init_rate_info rs_optimal_rates_24ghz_legacy[] = {
        { -60, IWL_RATE_54M_INDEX },
        { -64, IWL_RATE_48M_INDEX },
        { -68, IWL_RATE_36M_INDEX },
        { -80, IWL_RATE_24M_INDEX },
        { -84, IWL_RATE_18M_INDEX },
        { -85, IWL_RATE_12M_INDEX },
        { -86, IWL_RATE_11M_INDEX },
        { -88, IWL_RATE_5M_INDEX  },
        { -90, IWL_RATE_2M_INDEX  },
        { S8_MIN, IWL_RATE_1M_INDEX },
};

static const struct rs_init_rate_info rs_optimal_rates_5ghz_legacy[] = {
        { -60, IWL_RATE_54M_INDEX },
        { -64, IWL_RATE_48M_INDEX },
        { -72, IWL_RATE_36M_INDEX },
        { -80, IWL_RATE_24M_INDEX },
        { -84, IWL_RATE_18M_INDEX },
        { -85, IWL_RATE_12M_INDEX },
        { -87, IWL_RATE_9M_INDEX  },
        { S8_MIN, IWL_RATE_6M_INDEX },
};

static const struct rs_init_rate_info rs_optimal_rates_ht[] = {
        { -60, IWL_RATE_MCS_7_INDEX },
        { -64, IWL_RATE_MCS_6_INDEX },
        { -68, IWL_RATE_MCS_5_INDEX },
        { -72, IWL_RATE_MCS_4_INDEX },
        { -80, IWL_RATE_MCS_3_INDEX },
        { -84, IWL_RATE_MCS_2_INDEX },
        { -85, IWL_RATE_MCS_1_INDEX },
        { S8_MIN, IWL_RATE_MCS_0_INDEX},
};

/* MCS index 9 is not valid for 20MHz VHT channel width,
 * but is ok for 40, 80 and 160MHz channels.
 */
static const struct rs_init_rate_info rs_optimal_rates_vht_20mhz[] = {
        { -60, IWL_RATE_MCS_8_INDEX },
        { -64, IWL_RATE_MCS_7_INDEX },
        { -68, IWL_RATE_MCS_6_INDEX },
        { -72, IWL_RATE_MCS_5_INDEX },
        { -80, IWL_RATE_MCS_4_INDEX },
        { -84, IWL_RATE_MCS_3_INDEX },
        { -85, IWL_RATE_MCS_2_INDEX },
        { -87, IWL_RATE_MCS_1_INDEX },
        { S8_MIN, IWL_RATE_MCS_0_INDEX},
};

static const struct rs_init_rate_info rs_optimal_rates_vht[] = {
        { -60, IWL_RATE_MCS_9_INDEX },
        { -64, IWL_RATE_MCS_8_INDEX },
        { -68, IWL_RATE_MCS_7_INDEX },
        { -72, IWL_RATE_MCS_6_INDEX },
        { -80, IWL_RATE_MCS_5_INDEX },
        { -84, IWL_RATE_MCS_4_INDEX },
        { -85, IWL_RATE_MCS_3_INDEX },
        { -87, IWL_RATE_MCS_2_INDEX },
        { -88, IWL_RATE_MCS_1_INDEX },
        { S8_MIN, IWL_RATE_MCS_0_INDEX },
};

#define IWL_RS_LOW_RSSI_THRESHOLD (-76) /* dBm */

/* Init the optimal rate based on STA caps
 * This combined with rssi is used to report the last tx rate
 * to userspace when we haven't transmitted enough frames.
 */
static void rs_init_optimal_rate(struct iwl_mvm *mvm,
                                 struct ieee80211_sta *sta,
                                 struct iwl_lq_sta *lq_sta)
{
        struct rs_rate *rate = &lq_sta->optimal_rate;

        if (lq_sta->max_mimo2_rate_idx != IWL_RATE_INVALID)
                rate->type = lq_sta->is_vht ? LQ_VHT_MIMO2 : LQ_HT_MIMO2;
        else if (lq_sta->max_siso_rate_idx != IWL_RATE_INVALID)
                rate->type = lq_sta->is_vht ? LQ_VHT_SISO : LQ_HT_SISO;
        else if (lq_sta->band == NL80211_BAND_5GHZ)
                rate->type = LQ_LEGACY_A;
        else
                rate->type = LQ_LEGACY_G;

        rate->bw = rs_bw_from_sta_bw(sta);
        rate->sgi = rs_sgi_allow(mvm, sta, rate, NULL);

        /* ANT/LDPC/STBC aren't relevant for the rate reported to userspace */

        if (is_mimo(rate)) {
                lq_sta->optimal_rate_mask = lq_sta->active_mimo2_rate;
        } else if (is_siso(rate)) {
                lq_sta->optimal_rate_mask = lq_sta->active_siso_rate;
        } else {
                lq_sta->optimal_rate_mask = lq_sta->active_legacy_rate;

                if (lq_sta->band == NL80211_BAND_5GHZ) {
                        lq_sta->optimal_rates = rs_optimal_rates_5ghz_legacy;
                        lq_sta->optimal_nentries =
                                ARRAY_SIZE(rs_optimal_rates_5ghz_legacy);
                } else {
                        lq_sta->optimal_rates = rs_optimal_rates_24ghz_legacy;
                        lq_sta->optimal_nentries =
                                ARRAY_SIZE(rs_optimal_rates_24ghz_legacy);
                }
        }

        if (is_vht(rate)) {
                if (rate->bw == RATE_MCS_CHAN_WIDTH_20) {
                        lq_sta->optimal_rates = rs_optimal_rates_vht_20mhz;
                        lq_sta->optimal_nentries =
                                ARRAY_SIZE(rs_optimal_rates_vht_20mhz);
                } else {
                        lq_sta->optimal_rates = rs_optimal_rates_vht;
                        lq_sta->optimal_nentries =
                                ARRAY_SIZE(rs_optimal_rates_vht);
                }
        } else if (is_ht(rate)) {
                lq_sta->optimal_rates = rs_optimal_rates_ht;
                lq_sta->optimal_nentries = ARRAY_SIZE(rs_optimal_rates_ht);
        }
}

/* Compute the optimal rate index based on RSSI */
static struct rs_rate *rs_get_optimal_rate(struct iwl_mvm *mvm,
                                           struct iwl_lq_sta *lq_sta)
{
        struct rs_rate *rate = &lq_sta->optimal_rate;
        int i;

        rate->index = find_first_bit(&lq_sta->optimal_rate_mask,
                                     BITS_PER_LONG);

        for (i = 0; i < lq_sta->optimal_nentries; i++) {
                int rate_idx = lq_sta->optimal_rates[i].rate_idx;

                if ((lq_sta->pers.last_rssi >= lq_sta->optimal_rates[i].rssi) &&
                    (BIT(rate_idx) & lq_sta->optimal_rate_mask)) {
                        rate->index = rate_idx;
                        break;
                }
        }

        return rate;
}

/* Choose an initial legacy rate and antenna to use based on the RSSI
 * of last Rx
 */
static void rs_get_initial_rate(struct iwl_mvm *mvm,
                                struct ieee80211_sta *sta,
                                struct iwl_lq_sta *lq_sta,
                                enum nl80211_band band,
                                struct rs_rate *rate)
{
        int i, nentries;
        unsigned long active_rate;
        s8 best_rssi = S8_MIN;
        u8 best_ant = ANT_NONE;
        u8 valid_tx_ant = iwl_mvm_get_valid_tx_ant(mvm);
        const struct rs_init_rate_info *initial_rates;

        for (i = 0; i < ARRAY_SIZE(lq_sta->pers.chain_signal); i++) {
                if (!(lq_sta->pers.chains & BIT(i)))
                        continue;

                if (lq_sta->pers.chain_signal[i] > best_rssi) {
                        best_rssi = lq_sta->pers.chain_signal[i];
                        best_ant = BIT(i);
                }
        }

        IWL_DEBUG_RATE(mvm, "Best ANT: %s Best RSSI: %d\n",
                       rs_pretty_ant(best_ant), best_rssi);

        if (best_ant != ANT_A && best_ant != ANT_B)
                rate->ant = first_antenna(valid_tx_ant);
        else
                rate->ant = best_ant;

        rate->sgi = false;
        rate->ldpc = false;
        rate->bw = RATE_MCS_CHAN_WIDTH_20;

        rate->index = find_first_bit(&lq_sta->active_legacy_rate,
                                     BITS_PER_LONG);

        if (band == NL80211_BAND_5GHZ) {
                rate->type = LQ_LEGACY_A;
                initial_rates = rs_optimal_rates_5ghz_legacy;
                nentries = ARRAY_SIZE(rs_optimal_rates_5ghz_legacy);
        } else {
                rate->type = LQ_LEGACY_G;
                initial_rates = rs_optimal_rates_24ghz_legacy;
                nentries = ARRAY_SIZE(rs_optimal_rates_24ghz_legacy);
        }

        if (!IWL_MVM_RS_RSSI_BASED_INIT_RATE)
                goto out;

        /* Start from a higher rate if the corresponding debug capability
         * is enabled. The rate is chosen according to AP capabilities.
         * In case of VHT/HT when the rssi is low fallback to the case of
         * legacy rates.
         */
        if (sta->vht_cap.vht_supported &&
            best_rssi > IWL_RS_LOW_RSSI_THRESHOLD) {
                switch (sta->bandwidth) {
                case IEEE80211_STA_RX_BW_160:
                case IEEE80211_STA_RX_BW_80:
                case IEEE80211_STA_RX_BW_40:
                        initial_rates = rs_optimal_rates_vht;
                        nentries = ARRAY_SIZE(rs_optimal_rates_vht);
                        break;
                case IEEE80211_STA_RX_BW_20:
                        initial_rates = rs_optimal_rates_vht_20mhz;
                        nentries = ARRAY_SIZE(rs_optimal_rates_vht_20mhz);
                        break;
                default:
                        IWL_ERR(mvm, "Invalid BW %d\n", sta->bandwidth);
                        goto out;
                }

                active_rate = lq_sta->active_siso_rate;
                rate->type = LQ_VHT_SISO;
                rate->bw = rs_bw_from_sta_bw(sta);
        } else if (sta->ht_cap.ht_supported &&
                   best_rssi > IWL_RS_LOW_RSSI_THRESHOLD) {
                initial_rates = rs_optimal_rates_ht;
                nentries = ARRAY_SIZE(rs_optimal_rates_ht);
                active_rate = lq_sta->active_siso_rate;
                rate->type = LQ_HT_SISO;
        } else {
                active_rate = lq_sta->active_legacy_rate;
        }

        for (i = 0; i < nentries; i++) {
                int rate_idx = initial_rates[i].rate_idx;

                if ((best_rssi >= initial_rates[i].rssi) &&
                    (BIT(rate_idx) & active_rate)) {
                        rate->index = rate_idx;
                        break;
                }
        }

out:
        rs_dump_rate(mvm, rate, "INITIAL");
}

/* Save info about RSSI of last Rx */
void rs_update_last_rssi(struct iwl_mvm *mvm,
                         struct iwl_lq_sta *lq_sta,
                         struct ieee80211_rx_status *rx_status)
{
        int i;

        lq_sta->pers.chains = rx_status->chains;
        lq_sta->pers.chain_signal[0] = rx_status->chain_signal[0];
        lq_sta->pers.chain_signal[1] = rx_status->chain_signal[1];
        lq_sta->pers.chain_signal[2] = rx_status->chain_signal[2];
        lq_sta->pers.last_rssi = S8_MIN;

        for (i = 0; i < ARRAY_SIZE(lq_sta->pers.chain_signal); i++) {
                if (!(lq_sta->pers.chains & BIT(i)))
                        continue;

                if (lq_sta->pers.chain_signal[i] > lq_sta->pers.last_rssi)
                        lq_sta->pers.last_rssi = lq_sta->pers.chain_signal[i];
        }
}

/**
 * rs_initialize_lq - Initialize a station's hardware rate table
 *
 * The uCode's station table contains a table of fallback rates
 * for automatic fallback during transmission.
 *
 * NOTE: This sets up a default set of values.  These will be replaced later
 *       if the driver's iwl-agn-rs rate scaling algorithm is used, instead of
 *       rc80211_simple.
 *
 * NOTE: Run REPLY_ADD_STA command to set up station table entry, before
 *       calling this function (which runs REPLY_TX_LINK_QUALITY_CMD,
 *       which requires station table entry to exist).
 */
static void rs_initialize_lq(struct iwl_mvm *mvm,
                             struct ieee80211_sta *sta,
                             struct iwl_lq_sta *lq_sta,
                             enum nl80211_band band,
                             bool init)
{
        struct iwl_scale_tbl_info *tbl;
        struct rs_rate *rate;
        u8 active_tbl = 0;

        if (!sta || !lq_sta)
                return;

        if (!lq_sta->search_better_tbl)
                active_tbl = lq_sta->active_tbl;
        else
                active_tbl = 1 - lq_sta->active_tbl;

        tbl = &(lq_sta->lq_info[active_tbl]);
        rate = &tbl->rate;

        rs_get_initial_rate(mvm, sta, lq_sta, band, rate);
        rs_init_optimal_rate(mvm, sta, lq_sta);

        WARN_ON_ONCE(rate->ant != ANT_A && rate->ant != ANT_B);
        tbl->column = rs_get_column_from_rate(rate);

        rs_set_expected_tpt_table(lq_sta, tbl);
        rs_fill_lq_cmd(mvm, sta, lq_sta, rate);
        /* TODO restore station should remember the lq cmd */
        iwl_mvm_send_lq_cmd(mvm, &lq_sta->lq, init);
}

static void rs_get_rate(void *mvm_r, struct ieee80211_sta *sta, void *mvm_sta,
                        struct ieee80211_tx_rate_control *txrc)
{
        struct sk_buff *skb = txrc->skb;
        struct iwl_op_mode *op_mode __maybe_unused =
                        (struct iwl_op_mode *)mvm_r;
        struct iwl_mvm *mvm __maybe_unused = IWL_OP_MODE_GET_MVM(op_mode);
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        struct iwl_lq_sta *lq_sta = mvm_sta;
        struct rs_rate *optimal_rate;
        u32 last_ucode_rate;

        if (sta && !iwl_mvm_sta_from_mac80211(sta)->vif) {
                /* if vif isn't initialized mvm doesn't know about
                 * this station, so don't do anything with the it
                 */
                sta = NULL;
                mvm_sta = NULL;
        }

        /* TODO: handle rate_idx_mask and rate_idx_mcs_mask */

        /* Treat uninitialized rate scaling data same as non-existing. */
        if (lq_sta && !lq_sta->pers.drv) {
                IWL_DEBUG_RATE(mvm, "Rate scaling not initialized yet.\n");
                mvm_sta = NULL;
        }

        /* Send management frames and NO_ACK data using lowest rate. */
        if (rate_control_send_low(sta, mvm_sta, txrc))
                return;

        iwl_mvm_hwrate_to_tx_rate(lq_sta->last_rate_n_flags,
                                  info->band, &info->control.rates[0]);
        info->control.rates[0].count = 1;

        /* Report the optimal rate based on rssi and STA caps if we haven't
         * converged yet (too little traffic) or exploring other modulations
         */
        if (lq_sta->rs_state != RS_STATE_STAY_IN_COLUMN) {
                optimal_rate = rs_get_optimal_rate(mvm, lq_sta);
                last_ucode_rate = ucode_rate_from_rs_rate(mvm,
                                                          optimal_rate);
                iwl_mvm_hwrate_to_tx_rate(last_ucode_rate, info->band,
                                          &txrc->reported_rate);
        }
}

static void *rs_alloc_sta(void *mvm_rate, struct ieee80211_sta *sta,
                          gfp_t gfp)
{
        struct iwl_mvm_sta *sta_priv = iwl_mvm_sta_from_mac80211(sta);
        struct iwl_op_mode *op_mode = (struct iwl_op_mode *)mvm_rate;
        struct iwl_mvm *mvm  = IWL_OP_MODE_GET_MVM(op_mode);
        struct iwl_lq_sta *lq_sta = &sta_priv->lq_sta;

        IWL_DEBUG_RATE(mvm, "create station rate scale window\n");

        lq_sta->pers.drv = mvm;
#ifdef CONFIG_MAC80211_DEBUGFS
        lq_sta->pers.dbg_fixed_rate = 0;
        lq_sta->pers.dbg_fixed_txp_reduction = TPC_INVALID;
        lq_sta->pers.ss_force = RS_SS_FORCE_NONE;
#endif
        lq_sta->pers.chains = 0;
        memset(lq_sta->pers.chain_signal, 0, sizeof(lq_sta->pers.chain_signal));
        lq_sta->pers.last_rssi = S8_MIN;

        return &sta_priv->lq_sta;
}

static int rs_vht_highest_rx_mcs_index(struct ieee80211_sta_vht_cap *vht_cap,
                                       int nss)
{
        u16 rx_mcs = le16_to_cpu(vht_cap->vht_mcs.rx_mcs_map) &
                (0x3 << (2 * (nss - 1)));
        rx_mcs >>= (2 * (nss - 1));

        if (rx_mcs == IEEE80211_VHT_MCS_SUPPORT_0_7)
                return IWL_RATE_MCS_7_INDEX;
        else if (rx_mcs == IEEE80211_VHT_MCS_SUPPORT_0_8)
                return IWL_RATE_MCS_8_INDEX;
        else if (rx_mcs == IEEE80211_VHT_MCS_SUPPORT_0_9)
                return IWL_RATE_MCS_9_INDEX;

        WARN_ON_ONCE(rx_mcs != IEEE80211_VHT_MCS_NOT_SUPPORTED);
        return -1;
}

static void rs_vht_set_enabled_rates(struct ieee80211_sta *sta,
                                     struct ieee80211_sta_vht_cap *vht_cap,
                                     struct iwl_lq_sta *lq_sta)
{
        int i;
        int highest_mcs = rs_vht_highest_rx_mcs_index(vht_cap, 1);

        if (highest_mcs >= IWL_RATE_MCS_0_INDEX) {
                for (i = IWL_RATE_MCS_0_INDEX; i <= highest_mcs; i++) {
                        if (i == IWL_RATE_9M_INDEX)
                                continue;

                        /* VHT MCS9 isn't valid for 20Mhz for NSS=1,2 */
                        if (i == IWL_RATE_MCS_9_INDEX &&
                            sta->bandwidth == IEEE80211_STA_RX_BW_20)
                                continue;

                        lq_sta->active_siso_rate |= BIT(i);
                }
        }

        if (sta->rx_nss < 2)
                return;

        highest_mcs = rs_vht_highest_rx_mcs_index(vht_cap, 2);
        if (highest_mcs >= IWL_RATE_MCS_0_INDEX) {
                for (i = IWL_RATE_MCS_0_INDEX; i <= highest_mcs; i++) {
                        if (i == IWL_RATE_9M_INDEX)
                                continue;

                        /* VHT MCS9 isn't valid for 20Mhz for NSS=1,2 */
                        if (i == IWL_RATE_MCS_9_INDEX &&