/******************************************************************************
 *
 * Copyright(c) 2005 - 2013 Intel Corporation. All rights reserved.
 *
 * 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 <ilw@linux.intel.com>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *
 *****************************************************************************/
#include <linux/kernel.h>
#include <linux/init.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"

#define RS_NAME "iwl-mvm-rs"

#define NUM_TRY_BEFORE_ANT_TOGGLE 1
#define IWL_NUMBER_TRY      1
#define IWL_HT_NUMBER_TRY   3

#define IWL_RATE_MAX_WINDOW             62      /* # tx in history window */
#define IWL_RATE_MIN_FAILURE_TH         6       /* min failures to calc tpt */
#define IWL_RATE_MIN_SUCCESS_TH         8       /* min successes to calc tpt */

/* max allowed rate miss before sync LQ cmd */
#define IWL_MISSED_RATE_MAX             15
/* max time to accum history 2 seconds */
#define IWL_RATE_SCALE_FLUSH_INTVL   (3*HZ)

static u8 rs_ht_to_legacy[] = {
        IWL_RATE_6M_INDEX, IWL_RATE_6M_INDEX,
        IWL_RATE_6M_INDEX, IWL_RATE_6M_INDEX,
        IWL_RATE_6M_INDEX,
        IWL_RATE_6M_INDEX, IWL_RATE_9M_INDEX,
        IWL_RATE_12M_INDEX, IWL_RATE_18M_INDEX,
        IWL_RATE_24M_INDEX, IWL_RATE_36M_INDEX,
        IWL_RATE_48M_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, ip, in, rp, rn, pp, np)    \
        [IWL_RATE_##r##M_INDEX] = { IWL_RATE_##r##M_PLCP,      \
                                    IWL_RATE_SISO_##s##M_PLCP, \
                                    IWL_RATE_MIMO2_##s##M_PLCP,\
                                    IWL_RATE_MIMO3_##s##M_PLCP,\
                                    IWL_RATE_##r##M_IEEE,      \
                                    IWL_RATE_##ip##M_INDEX,    \
                                    IWL_RATE_##in##M_INDEX,    \
                                    IWL_RATE_##rp##M_INDEX,    \
                                    IWL_RATE_##rn##M_INDEX,    \
                                    IWL_RATE_##pp##M_INDEX,    \
                                    IWL_RATE_##np##M_INDEX }

/*
 * Parameter order:
 *   rate, ht rate, prev rate, next rate, prev tgg rate, next tgg 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, INV, 2, INV, 2),    /*  1mbps */
        IWL_DECLARE_RATE_INFO(2, INV, 1, 5, 1, 5, 1, 5),          /*  2mbps */
        IWL_DECLARE_RATE_INFO(5, INV, 2, 6, 2, 11, 2, 11),        /*5.5mbps */
        IWL_DECLARE_RATE_INFO(11, INV, 9, 12, 9, 12, 5, 18),      /* 11mbps */
        IWL_DECLARE_RATE_INFO(6, 6, 5, 9, 5, 11, 5, 11),        /*  6mbps */
        IWL_DECLARE_RATE_INFO(9, 6, 6, 11, 6, 11, 5, 11),       /*  9mbps */
        IWL_DECLARE_RATE_INFO(12, 12, 11, 18, 11, 18, 11, 18),   /* 12mbps */
        IWL_DECLARE_RATE_INFO(18, 18, 12, 24, 12, 24, 11, 24),   /* 18mbps */
        IWL_DECLARE_RATE_INFO(24, 24, 18, 36, 18, 36, 18, 36),   /* 24mbps */
        IWL_DECLARE_RATE_INFO(36, 36, 24, 48, 24, 48, 24, 48),   /* 36mbps */
        IWL_DECLARE_RATE_INFO(48, 48, 36, 54, 36, 54, 36, 54),   /* 48mbps */
        IWL_DECLARE_RATE_INFO(54, 54, 48, INV, 48, INV, 48, INV),/* 54mbps */
        IWL_DECLARE_RATE_INFO(60, 60, 48, INV, 48, INV, 48, INV),/* 60mbps */
        /* FIXME:RS:          ^^    should be INV (legacy) */
};

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;

        /* HT rate format */
        if (rate_n_flags & RATE_MCS_HT_MSK) {
                idx = rs_extract_rate(rate_n_flags);

                if (idx >= IWL_RATE_MIMO3_6M_PLCP)
                        idx = idx - IWL_RATE_MIMO3_6M_PLCP;
                else if (idx >= IWL_RATE_MIMO2_6M_PLCP)
                        idx = idx - IWL_RATE_MIMO2_6M_PLCP;

                idx += IWL_FIRST_OFDM_RATE;
                /* skip 9M not supported in ht*/
                if (idx >= IWL_RATE_9M_INDEX)
                        idx += 1;
                if ((idx >= IWL_FIRST_OFDM_RATE) && (idx <= IWL_LAST_OFDM_RATE))
                        return idx;

        /* legacy rate format, search for match in table */
        } else {
                for (idx = 0; idx < ARRAY_SIZE(iwl_rates); idx++)
                        if (iwl_rates[idx].plcp ==
                                        rs_extract_rate(rate_n_flags))
                                return idx;
        }

        return -1;
}

static void rs_rate_scale_perform(struct iwl_mvm *mvm,
                                   struct sk_buff *skb,
                                   struct ieee80211_sta *sta,
                                   struct iwl_lq_sta *lq_sta);
static void rs_fill_link_cmd(struct iwl_mvm *mvm,
                             struct iwl_lq_sta *lq_sta, u32 rate_n_flags);
static void rs_stay_in_table(struct iwl_lq_sta *lq_sta, bool force_search);


#ifdef CONFIG_MAC80211_DEBUGFS
static void rs_dbgfs_set_mcs(struct iwl_lq_sta *lq_sta,
                             u32 *rate_n_flags, int index);
#else
static void rs_dbgfs_set_mcs(struct iwl_lq_sta *lq_sta,
                             u32 *rate_n_flags, int index)
{}
#endif

/**
 * 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 s32 expected_tpt_legacy[IWL_RATE_COUNT] = {
        7, 13, 35, 58, 40, 57, 72, 98, 121, 154, 177, 186, 0
};

static s32 expected_tpt_siso20MHz[4][IWL_RATE_COUNT] = {
        {0, 0, 0, 0, 42, 0,  76, 102, 124, 159, 183, 193, 202}, /* Norm */
        {0, 0, 0, 0, 46, 0,  82, 110, 132, 168, 192, 202, 210}, /* SGI */
        {0, 0, 0, 0, 47, 0,  91, 133, 171, 242, 305, 334, 362}, /* AGG */
        {0, 0, 0, 0, 52, 0, 101, 145, 187, 264, 330, 361, 390}, /* AGG+SGI */
};

static s32 expected_tpt_siso40MHz[4][IWL_RATE_COUNT] = {
        {0, 0, 0, 0,  77, 0, 127, 160, 184, 220, 242, 250, 257}, /* Norm */
        {0, 0, 0, 0,  83, 0, 135, 169, 193, 229, 250, 257, 264}, /* SGI */
        {0, 0, 0, 0,  94, 0, 177, 249, 313, 423, 512, 550, 586}, /* AGG */
        {0, 0, 0, 0, 104, 0, 193, 270, 338, 454, 545, 584, 620}, /* AGG+SGI */
};

static s32 expected_tpt_mimo2_20MHz[4][IWL_RATE_COUNT] = {
        {0, 0, 0, 0,  74, 0, 123, 155, 179, 214, 236, 244, 251}, /* Norm */
        {0, 0, 0, 0,  81, 0, 131, 164, 188, 223, 243, 251, 257}, /* SGI */
        {0, 0, 0, 0,  89, 0, 167, 235, 296, 402, 488, 526, 560}, /* AGG */
        {0, 0, 0, 0,  97, 0, 182, 255, 320, 431, 520, 558, 593}, /* AGG+SGI*/
};

static s32 expected_tpt_mimo2_40MHz[4][IWL_RATE_COUNT] = {
        {0, 0, 0, 0, 123, 0, 182, 214, 235, 264, 279, 285, 289}, /* Norm */
        {0, 0, 0, 0, 131, 0, 191, 222, 242, 270, 284, 289, 293}, /* SGI */
        {0, 0, 0, 0, 171, 0, 305, 410, 496, 634, 731, 771, 805}, /* AGG */
        {0, 0, 0, 0, 186, 0, 329, 439, 527, 667, 764, 803, 838}, /* AGG+SGI */
};

static s32 expected_tpt_mimo3_20MHz[4][IWL_RATE_COUNT] = {
        {0, 0, 0, 0,  99, 0, 153, 186, 208, 239, 256, 263, 268}, /* Norm */
        {0, 0, 0, 0, 106, 0, 162, 194, 215, 246, 262, 268, 273}, /* SGI */
        {0, 0, 0, 0, 134, 0, 249, 346, 431, 574, 685, 732, 775}, /* AGG */
        {0, 0, 0, 0, 148, 0, 272, 376, 465, 614, 727, 775, 818}, /* AGG+SGI */
};

static s32 expected_tpt_mimo3_40MHz[4][IWL_RATE_COUNT] = {
        {0, 0, 0, 0, 152, 0, 211, 239, 255, 279,  290,  294,  297}, /* Norm */
        {0, 0, 0, 0, 160, 0, 219, 245, 261, 284,  294,  297,  300}, /* SGI */
        {0, 0, 0, 0, 254, 0, 443, 584, 695, 868,  984, 1030, 1070}, /* AGG */
        {0, 0, 0, 0, 277, 0, 478, 624, 737, 911, 1026, 1070, 1109}, /* AGG+SGI */
};

/* 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 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;
        window->stamp = 0;
}

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

/*
 *      removes the old data from the statistics. All data that is older than
 *      TID_MAX_TIME_DIFF, will be deleted.
 */
static void rs_tl_rm_old_stats(struct iwl_traffic_load *tl, u32 curr_time)
{
        /* The oldest age we want to keep */
        u32 oldest_time = curr_time - TID_MAX_TIME_DIFF;

        while (tl->queue_count &&
               (tl->time_stamp < oldest_time)) {
                tl->total -= tl->packet_count[tl->head];
                tl->packet_count[tl->head] = 0;
                tl->time_stamp += TID_QUEUE_CELL_SPACING;
                tl->queue_count--;
                tl->head++;
                if (tl->head >= TID_QUEUE_MAX_SIZE)
                        tl->head = 0;
        }
}

/*
 *      increment traffic load value for tid and also remove
 *      any old values if passed the certain time period
 */
static u8 rs_tl_add_packet(struct iwl_lq_sta *lq_data,
                           struct ieee80211_hdr *hdr)
{
        u32 curr_time = jiffies_to_msecs(jiffies);
        u32 time_diff;
        s32 index;
        struct iwl_traffic_load *tl = NULL;
        u8 tid;

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

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

        tl = &lq_data->load[tid];

        curr_time -= curr_time % TID_ROUND_VALUE;

        /* Happens only for the first packet. Initialize the data */
        if (!(tl->queue_count)) {
                tl->total = 1;
                tl->time_stamp = curr_time;
                tl->queue_count = 1;
                tl->head = 0;
                tl->packet_count[0] = 1;
                return IWL_MAX_TID_COUNT;
        }

        time_diff = TIME_WRAP_AROUND(tl->time_stamp, curr_time);
        index = time_diff / TID_QUEUE_CELL_SPACING;

        /* The history is too long: remove data that is older than */
        /* TID_MAX_TIME_DIFF */
        if (index >= TID_QUEUE_MAX_SIZE)
                rs_tl_rm_old_stats(tl, curr_time);

        index = (tl->head + index) % TID_QUEUE_MAX_SIZE;
        tl->packet_count[index] = tl->packet_count[index] + 1;
        tl->total = tl->total + 1;

        if ((index + 1) > tl->queue_count)
                tl->queue_count = index + 1;

        return tid;
}

#ifdef CONFIG_MAC80211_DEBUGFS
/**
 * Program the device to use fixed rate for frame transmit
 * This is for debugging/testing only
 * once the device start use fixed rate, we need to reload the module
 * to being back the normal operation.
 */
static void rs_program_fix_rate(struct iwl_mvm *mvm,
                                struct iwl_lq_sta *lq_sta)
{
        lq_sta->active_legacy_rate = 0x0FFF;    /* 1 - 54 MBits, includes CCK */
        lq_sta->active_siso_rate   = 0x1FD0;    /* 6 - 60 MBits, no 9, no CCK */
        lq_sta->active_mimo2_rate  = 0x1FD0;    /* 6 - 60 MBits, no 9, no CCK */
        lq_sta->active_mimo3_rate  = 0x1FD0;    /* 6 - 60 MBits, no 9, no CCK */

        IWL_DEBUG_RATE(mvm, "sta_id %d rate 0x%X\n",
                       lq_sta->lq.sta_id, lq_sta->dbg_fixed_rate);

        if (lq_sta->dbg_fixed_rate) {
                rs_fill_link_cmd(NULL, lq_sta, lq_sta->dbg_fixed_rate);
                iwl_mvm_send_lq_cmd(lq_sta->drv, &lq_sta->lq, CMD_ASYNC, false);
        }
}
#endif

/*
        get the traffic load value for tid
*/
static u32 rs_tl_get_load(struct iwl_lq_sta *lq_data, u8 tid)
{
        u32 curr_time = jiffies_to_msecs(jiffies);
        u32 time_diff;
        s32 index;
        struct iwl_traffic_load *tl = NULL;

        if (tid >= IWL_MAX_TID_COUNT)
                return 0;

        tl = &(lq_data->load[tid]);

        curr_time -= curr_time % TID_ROUND_VALUE;

        if (!(tl->queue_count))
                return 0;

        time_diff = TIME_WRAP_AROUND(tl->time_stamp, curr_time);
        index = time_diff / TID_QUEUE_CELL_SPACING;

        /* The history is too long: remove data that is older than */
        /* TID_MAX_TIME_DIFF */
        if (index >= TID_QUEUE_MAX_SIZE)
                rs_tl_rm_old_stats(tl, curr_time);

        return tl->total;
}

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;
        u32 load;

        load = rs_tl_get_load(lq_data, tid);

        /*
         * Don't create TX aggregation sessions when in high
         * BT traffic, as they would just be disrupted by BT.
         */
        if (BT_MBOX_MSG(&mvm->last_bt_notif, 3, TRAFFIC_LOAD) >= 2) {
                IWL_DEBUG_COEX(mvm, "BT traffic (%d), no aggregation allowed\n",
                               BT_MBOX_MSG(&mvm->last_bt_notif,
                                           3, TRAFFIC_LOAD));
                return ret;
        }

        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_scale_tbl_info *tbl,
                              int scale_index, int attempts, int successes)
{
        struct iwl_rate_scale_data *window = NULL;
        static const u64 mask = (((u64)1) << (IWL_RATE_MAX_WINDOW - 1));
        s32 fail_count, tpt;

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

        /* Select window for current tx bit rate */
        window = &(tbl->win[scale_index]);

        /* 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_RATE_MIN_FAILURE_TH) ||
            (window->success_counter >= IWL_RATE_MIN_SUCCESS_TH))
                window->average_tpt = (window->success_ratio * tpt + 64) / 128;
        else
                window->average_tpt = IWL_INVALID_VALUE;

        /* Tag this window as having been updated */
        window->stamp = jiffies;

        return 0;
}

/*
 * Fill uCode API rate_n_flags field, based on "search" or "active" table.
 */
/* FIXME:RS:remove this function and put the flags statically in the table */
static u32 rate_n_flags_from_tbl(struct iwl_mvm *mvm,
                                 struct iwl_scale_tbl_info *tbl,
                                 int index, u8 use_green)
{
        u32 rate_n_flags = 0;

        if (is_legacy(tbl->lq_type)) {
                rate_n_flags = iwl_rates[index].plcp;
                if (index >= IWL_FIRST_CCK_RATE && index <= IWL_LAST_CCK_RATE)
                        rate_n_flags |= RATE_MCS_CCK_MSK;
        } else if (is_Ht(tbl->lq_type)) {
                if (index > IWL_LAST_OFDM_RATE) {
                        IWL_ERR(mvm, "Invalid HT rate index %d\n", index);
                        index = IWL_LAST_OFDM_RATE;
                }
                rate_n_flags = RATE_MCS_HT_MSK;

                if (is_siso(tbl->lq_type))
                        rate_n_flags |= iwl_rates[index].plcp_siso;
                else if (is_mimo2(tbl->lq_type))
                        rate_n_flags |= iwl_rates[index].plcp_mimo2;
                else
                        rate_n_flags |= iwl_rates[index].plcp_mimo3;
        } else {
                IWL_ERR(mvm, "Invalid tbl->lq_type %d\n", tbl->lq_type);
        }

        rate_n_flags |= ((tbl->ant_type << RATE_MCS_ANT_POS) &
                                                     RATE_MCS_ANT_ABC_MSK);

        if (is_Ht(tbl->lq_type)) {
                if (tbl->is_ht40)
                        rate_n_flags |= RATE_MCS_CHAN_WIDTH_40;
                if (tbl->is_SGI)
                        rate_n_flags |= RATE_MCS_SGI_MSK;

                if (use_green) {
                        rate_n_flags |= RATE_HT_MCS_GF_MSK;
                        if (is_siso(tbl->lq_type) && tbl->is_SGI) {
                                rate_n_flags &= ~RATE_MCS_SGI_MSK;
                                IWL_ERR(mvm, "GF was set with SGI:SISO\n");
                        }
                }
        }
        return rate_n_flags;
}

/*
 * Interpret uCode API's rate_n_flags format,
 * fill "search" or "active" tx mode table.
 */
static int rs_get_tbl_info_from_mcs(const u32 rate_n_flags,
                                    enum ieee80211_band band,
                                    struct iwl_scale_tbl_info *tbl,
                                    int *rate_idx)
{
        u32 ant_msk = (rate_n_flags & RATE_MCS_ANT_ABC_MSK);
        u8 num_of_ant = get_num_of_ant_from_rate(rate_n_flags);
        u8 mcs;

        memset(tbl, 0, sizeof(struct iwl_scale_tbl_info));
        *rate_idx = iwl_hwrate_to_plcp_idx(rate_n_flags);

        if (*rate_idx  == IWL_RATE_INVALID) {
                *rate_idx = -1;
                return -EINVAL;
        }
        tbl->is_SGI = 0;        /* default legacy setup */
        tbl->is_ht40 = 0;
        tbl->ant_type = (ant_msk >> RATE_MCS_ANT_POS);
        tbl->lq_type = LQ_NONE;
        tbl->max_search = IWL_MAX_SEARCH;

        /* legacy rate format */
        if (!(rate_n_flags & RATE_MCS_HT_MSK)) {
                if (num_of_ant == 1) {
                        if (band == IEEE80211_BAND_5GHZ)
                                tbl->lq_type = LQ_A;
                        else
                                tbl->lq_type = LQ_G;
                }
        /* HT rate format */
        } else {
                if (rate_n_flags & RATE_MCS_SGI_MSK)
                        tbl->is_SGI = 1;

                if (rate_n_flags & RATE_MCS_CHAN_WIDTH_40) /* TODO */
                        tbl->is_ht40 = 1;

                mcs = rs_extract_rate(rate_n_flags);

                /* SISO */
                if (mcs <= IWL_RATE_SISO_60M_PLCP) {
                        if (num_of_ant == 1)
                                tbl->lq_type = LQ_SISO; /*else NONE*/
                /* MIMO2 */
                } else if (mcs <= IWL_RATE_MIMO2_60M_PLCP) {
                        if (num_of_ant == 2)
                                tbl->lq_type = LQ_MIMO2;
                /* MIMO3 */
                } else {
                        if (num_of_ant == 3) {
                                tbl->max_search = IWL_MAX_11N_MIMO3_SEARCH;
                                tbl->lq_type = LQ_MIMO3;
                        }
                }
        }
        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, u32 *rate_n_flags,
                             struct iwl_scale_tbl_info *tbl)
{
        u8 new_ant_type;

        if (!tbl->ant_type || tbl->ant_type > ANT_ABC)
                return 0;

        if (!rs_is_valid_ant(valid_ant, tbl->ant_type))
                return 0;

        new_ant_type = ant_toggle_lookup[tbl->ant_type];

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

        if (new_ant_type == tbl->ant_type)
                return 0;

        tbl->ant_type = new_ant_type;
        *rate_n_flags &= ~RATE_MCS_ANT_ABC_MSK;
        *rate_n_flags |= new_ant_type << RATE_MCS_ANT_POS;
        return 1;
}

/**
 * Green-field mode is valid if the station supports it and
 * there are no non-GF stations present in the BSS.
 */
static bool rs_use_green(struct ieee80211_sta *sta)
{
        /*
         * There's a bug somewhere in this code that causes the
         * scaling to get stuck because GF+SGI can't be combined
         * in SISO rates. Until we find that bug, disable GF, it
         * has only limited benefit and we still interoperate with
         * GF APs since we can always receive GF transmissions.
         */
        return false;
}

/**
 * rs_get_supported_rates - get the available rates
 *
 * if management frame or broadcast frame only return
 * basic available rates.
 *
 */
static u16 rs_get_supported_rates(struct iwl_lq_sta *lq_sta,
                                  struct ieee80211_hdr *hdr,
                                  enum iwl_table_type rate_type)
{
        if (is_legacy(rate_type)) {
                return lq_sta->active_legacy_rate;
        } else {
                if (is_siso(rate_type))
                        return lq_sta->active_siso_rate;
                else if (is_mimo2(rate_type))
                        return lq_sta->active_mimo2_rate;
                else
                        return lq_sta->active_mimo3_rate;
        }
}

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_a_band(rate_type) || !is_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;
                IWL_DEBUG_RATE(mvm, "Skipping masked lower rate: %d\n", low);
        }

        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;
                IWL_DEBUG_RATE(mvm, "Skipping masked higher rate: %d\n", high);
        }

        return (high << 8) | low;
}

static u32 rs_get_lower_rate(struct iwl_lq_sta *lq_sta,
                             struct iwl_scale_tbl_info *tbl,
                             u8 scale_index, u8 ht_possible)
{
        s32 low;
        u16 rate_mask;
        u16 high_low;
        u8 switch_to_legacy = 0;
        u8 is_green = lq_sta->is_green;
        struct iwl_mvm *mvm = lq_sta->drv;

        /* check if we need to switch from HT to legacy rates.
         * assumption is that mandatory rates (1Mbps or 6Mbps)
         * are always supported (spec demand) */
        if (!is_legacy(tbl->lq_type) && (!ht_possible || !scale_index)) {
                switch_to_legacy = 1;
                scale_index = rs_ht_to_legacy[scale_index];
                if (lq_sta->band == IEEE80211_BAND_5GHZ)
                        tbl->lq_type = LQ_A;
                else
                        tbl->lq_type = LQ_G;

                if (num_of_ant(tbl->ant_type) > 1)
                        tbl->ant_type =
                            first_antenna(iwl_fw_valid_tx_ant(mvm->fw));

                tbl->is_ht40 = 0;
                tbl->is_SGI = 0;
                tbl->max_search = IWL_MAX_SEARCH;
        }

        rate_mask = rs_get_supported_rates(lq_sta, NULL, tbl->lq_type);

        /* Mask with station rate restriction */
        if (is_legacy(tbl->lq_type)) {
                /* supp_rates has no CCK bits in A mode */
                if (lq_sta->band == IEEE80211_BAND_5GHZ)
                        rate_mask  = (u16)(rate_mask &
                           (lq_sta->supp_rates << IWL_FIRST_OFDM_RATE));
                else
                        rate_mask = (u16)(rate_mask & lq_sta->supp_rates);
        }

        /* If we switched from HT to legacy, check current rate */
        if (switch_to_legacy && (rate_mask & (1 << scale_index))) {
                low = scale_index;
                goto out;
        }

        high_low = rs_get_adjacent_rate(lq_sta->drv, scale_index, rate_mask,
                                        tbl->lq_type);
        low = high_low & 0xff;

        if (low == IWL_RATE_INVALID)
                low = scale_index;

out:
        return rate_n_flags_from_tbl(lq_sta->drv, tbl, low, is_green);
}

/*
 * Simple function to compare two rate scale table types
 */
static bool table_type_matches(struct iwl_scale_tbl_info *a,
                               struct iwl_scale_tbl_info *b)
{
        return (a->lq_type == b->lq_type) && (a->ant_type == b->ant_type) &&
                (a->is_SGI == b->is_SGI);
}

/*
 * mac80211 sends us Tx status
 */
static void rs_tx_status(void *mvm_r, struct ieee80211_supported_band *sband,
                         struct ieee80211_sta *sta, void *priv_sta,
                         struct sk_buff *skb)
{
        int legacy_success;
        int retries;
        int rs_index, mac_index, i;
        struct iwl_lq_sta *lq_sta = priv_sta;
        struct iwl_lq_cmd *table;
        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);
        enum mac80211_rate_control_flags mac_flags;
        u32 tx_rate;
        struct iwl_scale_tbl_info tbl_type;
        struct iwl_scale_tbl_info *curr_tbl, *other_tbl, *tmp_tbl;

        IWL_DEBUG_RATE_LIMIT(mvm,
                             "get frame ack response, update rate scale window\n");

        /* 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->drv) {
                IWL_DEBUG_RATE(mvm, "Rate scaling not initialized yet.\n");
                return;
        }

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

        /*
         * 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;
        tx_rate = le32_to_cpu(table->rs_table[0]);
        rs_get_tbl_info_from_mcs(tx_rate, info->band, &tbl_type, &rs_index);
        if (info->band == IEEE80211_BAND_5GHZ)
                rs_index -= IWL_FIRST_OFDM_RATE;
        mac_flags = info->status.rates[0].flags;
        mac_index = info->status.rates[0].idx;
        /* For HT packets, map MCS to PLCP */
        if (mac_flags & IEEE80211_TX_RC_MCS) {
                /* Remove # of streams */
                mac_index &= RATE_HT_MCS_RATE_CODE_MSK;
                if (mac_index >= (IWL_RATE_9M_INDEX - IWL_FIRST_OFDM_RATE))
                        mac_index++;
                /*
                 * mac80211 HT index is always zero-indexed; we need to move
                 * HT OFDM rates after CCK rates in 2.4 GHz band
                 */
                if (info->band == IEEE80211_BAND_2GHZ)
                        mac_index += IWL_FIRST_OFDM_RATE;
        }
        /* Here we actually compare this rate to the latest LQ command */
        if ((mac_index < 0) ||
            (tbl_type.is_SGI != !!(mac_flags & IEEE80211_TX_RC_SHORT_GI)) ||
            (tbl_type.is_ht40 != !!(mac_flags & IEEE80211_TX_RC_40_MHZ_WIDTH)) ||
            (tbl_type.ant_type != info->status.antenna) ||
            (!!(tx_rate & RATE_MCS_HT_MSK) !=
                                !!(mac_flags & IEEE80211_TX_RC_MCS)) ||
            (!!(tx_rate & RATE_HT_MCS_GF_MSK) !=
                                !!(mac_flags & IEEE80211_TX_RC_GREEN_FIELD)) ||
            (rs_index != mac_index)) {
                IWL_DEBUG_RATE(mvm,
                               "initial rate %d does not match %d (0x%x)\n",
                               mac_index, rs_index, tx_rate);
                /*
                 * 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_MISSED_RATE_MAX) {
                        lq_sta->missed_rate_counter = 0;
                        iwl_mvm_send_lq_cmd(mvm, &lq_sta->lq, CMD_ASYNC, 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;

        /* Figure out if rate scale algorithm is in active or search table */
        if (table_type_matches(&tbl_type,
                               &(lq_sta->lq_info[lq_sta->active_tbl]))) {
                curr_tbl = &(lq_sta->lq_info[lq_sta->active_tbl]);
                other_tbl = &(lq_sta->lq_info[1 - lq_sta->active_tbl]);
        } else if (table_type_matches(
                        &tbl_type, &lq_sta->lq_info[1 - lq_sta->active_tbl])) {
                curr_tbl = &(lq_sta->lq_info[1 - lq_sta->active_tbl]);
                other_tbl = &(lq_sta->lq_info[lq_sta->active_tbl]);
        } else {
                IWL_DEBUG_RATE(mvm,
                               "Neither active nor search matches tx rate\n");
                tmp_tbl = &(lq_sta->lq_info[lq_sta->active_tbl]);
                IWL_DEBUG_RATE(mvm, "active- lq:%x, ant:%x, SGI:%d\n",
                               tmp_tbl->lq_type, tmp_tbl->ant_type,
                               tmp_tbl->is_SGI);
                tmp_tbl = &(lq_sta->lq_info[1 - lq_sta->active_tbl]);
                IWL_DEBUG_RATE(mvm, "search- lq:%x, ant:%x, SGI:%d\n",
                               tmp_tbl->lq_type, tmp_tbl->ant_type,
                               tmp_tbl->is_SGI);
                IWL_DEBUG_RATE(mvm, "actual- lq:%x, ant:%x, SGI:%d\n",
                               tbl_type.lq_type, tbl_type.ant_type,
                               tbl_type.is_SGI);
                /*
                 * 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) {
                tx_rate = le32_to_cpu(table->rs_table[0]);
                rs_get_tbl_info_from_mcs(tx_rate, info->band, &tbl_type,
                                         &rs_index);
                rs_collect_tx_data(curr_tbl, rs_index,
                                   info->status.ampdu_len,
                                   info->status.ampdu_ack_len);

                /* Update success/fail counts if not searching for new mode */
                if (lq_sta->stay_in_tbl) {
                        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) {
                        tx_rate = le32_to_cpu(table->rs_table[i]);
                        rs_get_tbl_info_from_mcs(tx_rate, info->band,
                                                 &tbl_type, &rs_index);
                        /*
                         * Only collect stats if retried rate is in the same RS
                         * table as active/search.
                         */
                        if (table_type_matches(&tbl_type, curr_tbl))
                                tmp_tbl = curr_tbl;
                        else if (table_type_matches(&tbl_type, other_tbl))
                                tmp_tbl = other_tbl;
                        else
                                continue;
                        rs_collect_tx_data(tmp_tbl, rs_index, 1,
                                           i < retries ? 0 : legacy_success);
                }

                /* Update success/fail counts if not searching for new mode */
                if (lq_sta->stay_in_tbl) {
                        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 = tx_rate;
done:
        /* See if there's a better rate or modulation mode to try. */
        if (sta && sta->supp_rates[sband->band])
                rs_rate_scale_perform(mvm, skb, sta, lq_sta);
}

/*
 * 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, "we are staying in the same table\n");
        lq_sta->stay_in_tbl = 1;        /* only place this gets set */
        if (is_legacy) {
                lq_sta->table_count_limit = IWL_LEGACY_TABLE_COUNT;
                lq_sta->max_failure_limit = IWL_LEGACY_FAILURE_LIMIT;
                lq_sta->max_success_limit = IWL_LEGACY_SUCCESS_LIMIT;
        } else {
                lq_sta->table_count_limit = IWL_NONE_LEGACY_TABLE_COUNT;
                lq_sta->max_failure_limit = IWL_NONE_LEGACY_FAILURE_LIMIT;
                lq_sta->max_success_limit = IWL_NONE_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->action_counter = 0;
}

/*
 * Find correct throughput table for given mode of modulation
 */
static void rs_set_expected_tpt_table(struct iwl_lq_sta *lq_sta,
                                      struct iwl_scale_tbl_info *tbl)
{
        /* Used to choose among HT tables */
        s32 (*ht_tbl_pointer)[IWL_RATE_COUNT];

        /* Check for invalid LQ type */
        if (WARN_ON_ONCE(!is_legacy(tbl->lq_type) && !is_Ht(tbl->lq_type))) {
                tbl->expected_tpt = expected_tpt_legacy;
                return;
        }

        /* Legacy rates have only one table */
        if (is_legacy(tbl->lq_type)) {
                tbl->expected_tpt = expected_tpt_legacy;
                return;
        }

        /* Choose among many HT tables depending on number of streams
         * (SISO/MIMO2/MIMO3), channel width (20/40), SGI, and aggregation
         * status */
        if (is_siso(tbl->lq_type) && !tbl->is_ht40)
                ht_tbl_pointer = expected_tpt_siso20MHz;
        else if (is_siso(tbl->lq_type))
                ht_tbl_pointer = expected_tpt_siso40MHz;
        else if (is_mimo2(tbl->lq_type) && !tbl->is_ht40)
                ht_tbl_pointer = expected_tpt_mimo2_20MHz;
        else if (is_mimo2(tbl->lq_type))
                ht_tbl_pointer = expected_tpt_mimo2_40MHz;
        else if (is_mimo3(tbl->lq_type) && !tbl->is_ht40)
                ht_tbl_pointer = expected_tpt_mimo3_20MHz;
        else /* if (is_mimo3(tbl->lq_type)) <-- must be true */
                ht_tbl_pointer = expected_tpt_mimo3_40MHz;

        if (!tbl->is_SGI && !lq_sta->is_agg)            /* Normal */
                tbl->expected_tpt = ht_tbl_pointer[0];
        else if (tbl->is_SGI && !lq_sta->is_agg)        /* SGI */
                tbl->expected_tpt = ht_tbl_pointer[1];
        else if (!tbl->is_SGI && lq_sta->is_agg)        /* AGG */
                tbl->expected_tpt = ht_tbl_pointer[2];
        else                                            /* AGG+SGI */
                tbl->expected_tpt = ht_tbl_pointer[3];
}

/*
 * Find starting rate for new "search" high-throughput mode of modulation.
 * Goal is to find lowest expected rate (under perfect conditions) that is
 * above the current measured throughput of "active" mode, to give new mode
 * a fair chance to prove itself without too many challenges.
 *
 * This gets called when transitioning to more aggressive modulation
 * (i.e. legacy to SISO or MIMO, or SISO to MIMO), as well as less aggressive
 * (i.e. MIMO to SISO).  When moving to MIMO, bit rate will typically need
 * to decrease to match "active" throughput.  When moving from MIMO to SISO,
 * bit rate will typically need to increase, but not if performance was bad.
 */
static s32 rs_get_best_rate(struct iwl_mvm *mvm,
                            struct iwl_lq_sta *lq_sta,
                            struct iwl_scale_tbl_info *tbl,     /* "search" */
                            u16 rate_mask, s8 index)
{
        /* "active" values */
        struct iwl_scale_tbl_info *active_tbl =
            &(lq_sta->lq_info[lq_sta->active_tbl]);
        s32 active_sr = active_tbl->win[index].success_ratio;
        s32 active_tpt = active_tbl->expected_tpt[index];

        /* expected "search" throughput */
        s32 *tpt_tbl = tbl->expected_tpt;

        s32 new_rate, high, low, start_hi;
        u16 high_low;
        s8 rate = index;

        new_rate = high = low = start_hi = IWL_RATE_INVALID;

        while (1) {
                high_low = rs_get_adjacent_rate(mvm, rate, rate_mask,
                                                tbl->lq_type);

                low = high_low & 0xff;
                high = (high_low >> 8) & 0xff;

                /*
                 * Lower the "search" bit rate, to give new "search" mode
                 * approximately the same throughput as "active" if:
                 *
                 * 1) "Active" mode has been working modestly well (but not
                 *    great), and expected "search" throughput (under perfect
                 *    conditions) at candidate rate is above the actual
                 *    measured "active" throughput (but less than expected
                 *    "active" throughput under perfect conditions).
                 * OR
                 * 2) "Active" mode has been working perfectly or very well
                 *    and expected "search" throughput (under perfect
                 *    conditions) at candidate rate is above expected
                 *    "active" throughput (under perfect conditions).
                 */
                if ((((100 * tpt_tbl[rate]) > lq_sta->last_tpt) &&
                     ((active_sr > IWL_RATE_DECREASE_TH) &&
                      (active_sr <= IWL_RATE_HIGH_TH) &&
                      (tpt_tbl[rate] <= active_tpt))) ||
                    ((active_sr >= IWL_RATE_SCALE_SWITCH) &&
                     (tpt_tbl[rate] > active_tpt))) {
                        /* (2nd or later pass)
                         * If we've already tried to raise the rate, and are
                         * now trying to lower it, use the higher rate. */
                        if (start_hi != IWL_RATE_INVALID) {
                                new_rate = start_hi;
                                break;
                        }

                        new_rate = rate;

                        /* Loop again with lower rate */
                        if (low != IWL_RATE_INVALID)
                                rate = low;

                        /* Lower rate not available, use the original */
                        else
                                break;

                /* Else try to raise the "search" rate to match "active" */
                } else {
                        /* (2nd or later pass)
                         * If we've already tried to lower the rate, and are
                         * now trying to raise it, use the lower rate. */
                        if (new_rate != IWL_RATE_INVALID)
                                break;

                        /* Loop again with higher rate */
                        else if (high != IWL_RATE_INVALID) {
                                start_hi = high;
                                rate = high;

                        /* Higher rate not available, use the original */
                        } else {
                                new_rate = rate;
                                break;
                        }
                }
        }

        return new_rate;
}

static bool iwl_is_ht40_tx_allowed(struct ieee80211_sta *sta)
{
        return sta->bandwidth >= IEEE80211_STA_RX_BW_40;
}

/*
 * Set up search table for MIMO2
 */
static int rs_switch_to_mimo2(struct iwl_mvm *mvm,
                             struct iwl_lq_sta *lq_sta,
                             struct ieee80211_sta *sta,
                             struct iwl_scale_tbl_info *tbl, int index)
{
        u16 rate_mask;
        s32 rate;
        s8 is_green = lq_sta->is_green;

        if (!sta->ht_cap.ht_supported)
                return -1;

        if (sta->smps_mode == IEEE80211_SMPS_STATIC)
                return -1;

        /* Need both Tx chains/antennas to support MIMO */
        if (num_of_ant(iwl_fw_valid_tx_ant(mvm->fw)) < 2)
                return -1;

        IWL_DEBUG_RATE(mvm, "LQ: try to switch to MIMO2\n");

        tbl->lq_type = LQ_MIMO2;
        tbl->action = 0;
        tbl->max_search = IWL_MAX_SEARCH;
        rate_mask = lq_sta->active_mimo2_rate;

        if (iwl_is_ht40_tx_allowed(sta))
                tbl->is_ht40 = 1;
        else
                tbl->is_ht40 = 0;

        rs_set_expected_tpt_table(lq_sta, tbl);

        rate = rs_get_best_rate(mvm, lq_sta, tbl, rate_mask, index);

        IWL_DEBUG_RATE(mvm, "LQ: MIMO2 best rate %d mask %X\n",
                       rate, rate_mask);
        if ((rate == IWL_RATE_INVALID) || !((1 << rate) & rate_mask)) {
                IWL_DEBUG_RATE(mvm, "Can't switch with index %d rate mask %x\n",
                               rate, rate_mask);
                return -1;
        }
        tbl->current_rate = rate_n_flags_from_tbl(mvm, tbl, rate, is_green);

        IWL_DEBUG_RATE(mvm, "LQ: Switch to new mcs %X index is green %X\n",
                       tbl->current_rate, is_green);
        return 0;
}

/*
 * Set up search table for MIMO3
 */
static int rs_switch_to_mimo3(struct iwl_mvm *mvm,
                             struct iwl_lq_sta *lq_sta,
                             struct ieee80211_sta *sta,
                             struct iwl_scale_tbl_info *tbl, int index)
{
        u16 rate_mask;
        s32 rate;
        s8 is_green = lq_sta->is_green;

        if (!sta->ht_cap.ht_supported)
                return -1;

        if (sta->smps_mode == IEEE80211_SMPS_STATIC)
                return -1;

        /* Need both Tx chains/antennas to support MIMO */
        if (num_of_ant(iwl_fw_valid_tx_ant(mvm->fw)) < 3)
                return -1;

        IWL_DEBUG_RATE(mvm, "LQ: try to switch to MIMO3\n");

        tbl->lq_type = LQ_MIMO3;
        tbl->action = 0;
        tbl->max_search = IWL_MAX_11N_MIMO3_SEARCH;
        rate_mask = lq_sta->active_mimo3_rate;

        if (iwl_is_ht40_tx_allowed(sta))
                tbl->is_ht40 = 1;
        else
                tbl->is_ht40 = 0;

        rs_set_expected_tpt_table(lq_sta, tbl);

        rate = rs_get_best_rate(mvm, lq_sta, tbl, rate_mask, index);

        IWL_DEBUG_RATE(mvm, "LQ: MIMO3 best rate %d mask %X\n",
                       rate, rate_mask);
        if ((rate == IWL_RATE_INVALID) || !((1 << rate) & rate_mask)) {
                IWL_DEBUG_RATE(mvm, "Can't switch with index %d rate mask %x\n",
                               rate, rate_mask);
                return -1;
        }
        tbl->current_rate = rate_n_flags_from_tbl(mvm, tbl, rate, is_green);

        IWL_DEBUG_RATE(mvm, "LQ: Switch to new mcs %X index is green %X\n",
                       tbl->current_rate, is_green);
        return 0;
}

/*
 * Set up search table for SISO
 */
static int rs_switch_to_siso(struct iwl_mvm *mvm,
                             struct iwl_lq_sta *lq_sta,
                             struct ieee80211_sta *sta,
                             struct iwl_scale_tbl_info *tbl, int index)
{
        u16 rate_mask;
        u8 is_green = lq_sta->is_green;
        s32 rate;

        if (!sta->ht_cap.ht_supported)
                return -1;

        IWL_DEBUG_RATE(mvm, "LQ: try to switch to SISO\n");

        tbl->lq_type = LQ_SISO;
        tbl->action = 0;
        tbl->max_search = IWL_MAX_SEARCH;
        rate_mask = lq_sta->active_siso_rate;

        if (iwl_is_ht40_tx_allowed(sta))
                tbl->is_ht40 = 1;
        else
                tbl->is_ht40 = 0;

        if (is_green)
                tbl->is_SGI = 0; /*11n spec: no SGI in SISO+Greenfield*/

        rs_set_expected_tpt_table(lq_sta, tbl);
        rate = rs_get_best_rate(mvm, lq_sta, tbl, rate_mask, index);

        IWL_DEBUG_RATE(mvm, "LQ: get best rate %d mask %X\n", rate, rate_mask);
        if ((rate == IWL_RATE_INVALID) || !((1 << rate) & rate_mask)) {
                IWL_DEBUG_RATE(mvm,
                               "can not switch with index %d rate mask %x\n",
                               rate, rate_mask);
                return -1;
        }
        tbl->current_rate = rate_n_flags_from_tbl(mvm, tbl, rate, is_green);
        IWL_DEBUG_RATE(mvm, "LQ: Switch to new mcs %X index is green %X\n",
                       tbl->current_rate, is_green);
        return 0;
}

/*
 * Try to switch to new modulation mode from legacy
 */
static int rs_move_legacy_other(struct iwl_mvm *mvm,
                                struct iwl_lq_sta *lq_sta,
                                struct ieee80211_sta *sta,
                                int index)
{
        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 iwl_rate_scale_data *window = &(tbl->win[index]);
        u32 sz = (sizeof(struct iwl_scale_tbl_info) -
                  (sizeof(struct iwl_rate_scale_data) * IWL_RATE_COUNT));
        u8 start_action;
        u8 valid_tx_ant = iwl_fw_valid_tx_ant(mvm->fw);
        u8 tx_chains_num = num_of_ant(valid_tx_ant);
        int ret;
        u8 update_search_tbl_counter = 0;

        start_action = tbl->action;
        while (1) {
                lq_sta->action_counter++;
                switch (tbl->action) {
                case IWL_LEGACY_SWITCH_ANTENNA1:
                case IWL_LEGACY_SWITCH_ANTENNA2:
                        IWL_DEBUG_RATE(mvm, "LQ: Legacy toggle Antenna\n");

                        if ((tbl->action == IWL_LEGACY_SWITCH_ANTENNA1 &&
                             tx_chains_num <= 1) ||
                            (tbl->action == IWL_LEGACY_SWITCH_ANTENNA2 &&
                             tx_chains_num <= 2))
                                break;

                        /* Don't change antenna if success has been great */
                        if (window->success_ratio >= IWL_RS_GOOD_RATIO)
                                break;

                        /* Set up search table to try other antenna */
                        memcpy(search_tbl, tbl, sz);

                        if (rs_toggle_antenna(valid_tx_ant,
                                              &search_tbl->current_rate,
                                              search_tbl)) {
                                update_search_tbl_counter = 1;
                                rs_set_expected_tpt_table(lq_sta, search_tbl);
                                goto out;
                        }
                        break;
                case IWL_LEGACY_SWITCH_SISO:
                        IWL_DEBUG_RATE(mvm, "LQ: Legacy switch to SISO\n");

                        /* Set up search table to try SISO */
                        memcpy(search_tbl, tbl, sz);
                        search_tbl->is_SGI = 0;
                        ret = rs_switch_to_siso(mvm, lq_sta, sta,
                                                 search_tbl, index);
                        if (!ret) {
                                lq_sta->action_counter = 0;
                                goto out;
                        }

                        break;
                case IWL_LEGACY_SWITCH_MIMO2_AB:
                case IWL_LEGACY_SWITCH_MIMO2_AC:
                case IWL_LEGACY_SWITCH_MIMO2_BC:
                        IWL_DEBUG_RATE(mvm, "LQ: Legacy switch to MIMO2\n");

                        /* Set up search table to try MIMO */
                        memcpy(search_tbl, tbl, sz);
                        search_tbl->is_SGI = 0;

                        if (tbl->action == IWL_LEGACY_SWITCH_MIMO2_AB)
                                search_tbl->ant_type = ANT_AB;
                        else if (tbl->action == IWL_LEGACY_SWITCH_MIMO2_AC)
                                search_tbl->ant_type = ANT_AC;
                        else
                                search_tbl->ant_type = ANT_BC;

                        if (!rs_is_valid_ant(valid_tx_ant,
                                             search_tbl->ant_type))
                                break;

                        ret = rs_switch_to_mimo2(mvm, lq_sta, sta,
                                                 search_tbl, index);
                        if (!ret) {
                                lq_sta->action_counter = 0;
                                goto out;
                        }
                        break;

                case IWL_LEGACY_SWITCH_MIMO3_ABC:
                        IWL_DEBUG_RATE(mvm, "LQ: Legacy switch to MIMO3\n");

                        /* Set up search table to try MIMO3 */
                        memcpy(search_tbl, tbl, sz);
                        search_tbl->is_SGI = 0;

                        search_tbl->ant_type = ANT_ABC;

                        if (!rs_is_valid_ant(valid_tx_ant,
                                             search_tbl->ant_type))
                                break;

                        ret = rs_switch_to_mimo3(mvm, lq_sta, sta,
                                                 search_tbl, index);
                        if (!ret) {
                                lq_sta->action_counter = 0;
                                goto out;
                        }
                        break;
                }
                tbl->action++;
                if (tbl->action > IWL_LEGACY_SWITCH_MIMO3_ABC)
                        tbl->action = IWL_LEGACY_SWITCH_ANTENNA1;

                if (tbl->action == start_action)
                        break;
        }
        search_tbl->lq_type = LQ_NONE;
        return 0;

out:
        lq_sta->search_better_tbl = 1;
        tbl->action++;
        if (tbl->action > IWL_LEGACY_SWITCH_MIMO3_ABC)
                tbl->action = IWL_LEGACY_SWITCH_ANTENNA1;
        if (update_search_tbl_counter)
                search_tbl->action = tbl->action;
        return 0;
}

/*
 * Try to switch to new modulation mode from SISO
 */
static int rs_move_siso_to_other(struct iwl_mvm *mvm,
                                 struct iwl_lq_sta *lq_sta,
                                 struct ieee80211_sta *sta, int index)
{
        u8 is_green = lq_sta->is_green;
        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 iwl_rate_scale_data *window = &(tbl->win[index]);
        struct ieee80211_sta_ht_cap *ht_cap = &sta->ht_cap;
        u32 sz = (sizeof(struct iwl_scale_tbl_info) -
                  (sizeof(struct iwl_rate_scale_data) * IWL_RATE_COUNT));
        u8 start_action;
        u8 valid_tx_ant = iwl_fw_valid_tx_ant(mvm->fw);
        u8 tx_chains_num = num_of_ant(valid_tx_ant);
        u8 update_search_tbl_counter = 0;
        int ret;

        switch (BT_MBOX_MSG(&mvm->last_bt_notif, 3, TRAFFIC_LOAD)) {
        case IWL_BT_COEX_TRAFFIC_LOAD_NONE:
                /* nothing */
                break;
        case IWL_BT_COEX_TRAFFIC_LOAD_LOW:
                /* avoid antenna B unless MIMO */
                if (tbl->action == IWL_SISO_SWITCH_ANTENNA2)
                        tbl->action = IWL_SISO_SWITCH_MIMO2_AB;
                break;
        case IWL_BT_COEX_TRAFFIC_LOAD_HIGH:
        case IWL_BT_COEX_TRAFFIC_LOAD_CONTINUOUS:
                /* avoid antenna B and MIMO */
                valid_tx_ant =
                        first_antenna(iwl_fw_valid_tx_ant(mvm->fw));
                if (tbl->action != IWL_SISO_SWITCH_ANTENNA1)
                        tbl->action = IWL_SISO_SWITCH_ANTENNA1;
                break;
        default:
                IWL_ERR(mvm, "Invalid BT load %d",
                        BT_MBOX_MSG(&mvm->last_bt_notif, 3, TRAFFIC_LOAD));
                break;
        }

        start_action = tbl->action;
        while (1) {
                lq_sta->action_counter++;
                switch (tbl->action) {
                case IWL_SISO_SWITCH_ANTENNA1:
                case IWL_SISO_SWITCH_ANTENNA2:
                        IWL_DEBUG_RATE(mvm, "LQ: SISO toggle Antenna\n");
                        if ((tbl->action == IWL_SISO_SWITCH_ANTENNA1 &&
                             tx_chains_num <= 1) ||
                            (tbl->action == IWL_SISO_SWITCH_ANTENNA2 &&
                             tx_chains_num <= 2))
                                break;

                        if (window->success_ratio >= IWL_RS_GOOD_RATIO &&
                            BT_MBOX_MSG(&mvm->last_bt_notif, 3,
                                        TRAFFIC_LOAD) == 0)
                                break;

                        memcpy(search_tbl, tbl, sz);
                        if (rs_toggle_antenna(valid_tx_ant,
                                              &search_tbl->current_rate,
                                              search_tbl)) {
                                update_search_tbl_counter = 1;
                                goto out;
                        }
                        break;
                case IWL_SISO_SWITCH_MIMO2_AB:
                case IWL_SISO_SWITCH_MIMO2_AC:
                case IWL_SISO_SWITCH_MIMO2_BC:
                        IWL_DEBUG_RATE(mvm, "LQ: SISO switch to MIMO2\n");
                        memcpy(search_tbl, tbl, sz);
                        search_tbl->is_SGI = 0;

                        if (tbl->action == IWL_SISO_SWITCH_MIMO2_AB)
                                search_tbl->ant_type = ANT_AB;
                        else if (tbl->action == IWL_SISO_SWITCH_MIMO2_AC)
                                search_tbl->ant_type = ANT_AC;
                        else
                                search_tbl->ant_type = ANT_BC;

                        if (!rs_is_valid_ant(valid_tx_ant,
                                             search_tbl->ant_type))
                                break;

                        ret = rs_switch_to_mimo2(mvm, lq_sta, sta,
                                                 search_tbl, index);
                        if (!ret)
                                goto out;
                        break;
                case IWL_SISO_SWITCH_GI:
                        if (!tbl->is_ht40 && !(ht_cap->cap &
                                                IEEE80211_HT_CAP_SGI_20))
                                break;
                        if (tbl->is_ht40 && !(ht_cap->cap &
                                                IEEE80211_HT_CAP_SGI_40))
                                break;

                        IWL_DEBUG_RATE(mvm, "LQ: SISO toggle SGI/NGI\n");

                        memcpy(search_tbl, tbl, sz);
                        if (is_green) {
                                if (!tbl->is_SGI)
                                        break;
                                else
                                        IWL_ERR(mvm,
                                                "SGI was set in GF+SISO\n");
                        }
                        search_tbl->is_SGI = !tbl->is_SGI;
                        rs_set_expected_tpt_table(lq_sta, search_tbl);
                        if (tbl->is_SGI) {
                                s32 tpt = lq_sta->last_tpt / 100;
                                if (tpt >= search_tbl->expected_tpt[index])
                                        break;
                        }
                        search_tbl->current_rate =
                                rate_n_flags_from_tbl(mvm, search_tbl,
                                                      index, is_green);
                        update_search_tbl_counter = 1;
                        goto out;
                case IWL_SISO_SWITCH_MIMO3_ABC:
                        IWL_DEBUG_RATE(mvm, "LQ: SISO switch to MIMO3\n");
                        memcpy(search_tbl, tbl, sz);
                        search_tbl->is_SGI = 0;
                        search_tbl->ant_type = ANT_ABC;

                        if (!rs_is_valid_ant(valid_tx_ant,
                                             search_tbl->ant_type))
                                break;

                        ret = rs_switch_to_mimo3(mvm, lq_sta, sta,
                                                 search_tbl, index);
                        if (!ret)
                                goto out;
                        break;
                }
                tbl->action++;
                if (tbl->action > IWL_LEGACY_SWITCH_MIMO3_ABC)
                        tbl->action = IWL_SISO_SWITCH_ANTENNA1;

                if (tbl->action == start_action)
                        break;
        }
        search_tbl->lq_type = LQ_NONE;
        return 0;

 out:
        lq_sta->search_better_tbl = 1;
        tbl->action++;
        if (tbl->action > IWL_SISO_SWITCH_MIMO3_ABC)
                tbl->action = IWL_SISO_SWITCH_ANTENNA1;
        if (update_search_tbl_counter)
                search_tbl->action = tbl->action;

        return 0;
}

/*
 * Try to switch to new modulation mode from MIMO2
 */
static int rs_move_mimo2_to_other(struct iwl_mvm *mvm,
                                 struct iwl_lq_sta *lq_sta,
                                 struct ieee80211_sta *sta, int index)
{
        s8 is_green = lq_sta->is_green;
        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 iwl_rate_scale_data *window = &(tbl->win[index]);
        struct ieee80211_sta_ht_cap *ht_cap = &sta->ht_cap;
        u32 sz = (sizeof(struct iwl_scale_tbl_info) -
                  (sizeof(struct iwl_rate_scale_data) * IWL_RATE_COUNT));
        u8 start_action;
        u8 valid_tx_ant = iwl_fw_valid_tx_ant(mvm->fw);
        u8 tx_chains_num = num_of_ant(valid_tx_ant);
        u8 update_search_tbl_counter = 0;
        int ret;

        switch (BT_MBOX_MSG(&mvm->last_bt_notif, 3, TRAFFIC_LOAD)) {
        case IWL_BT_COEX_TRAFFIC_LOAD_NONE:
                /* nothing */
                break;
        case IWL_BT_COEX_TRAFFIC_LOAD_HIGH:
        case IWL_BT_COEX_TRAFFIC_LOAD_CONTINUOUS:
                /* avoid antenna B and MIMO */
                if (tbl->action != IWL_MIMO2_SWITCH_SISO_A)
                        tbl->action = IWL_MIMO2_SWITCH_SISO_A;
                break;
        case IWL_BT_COEX_TRAFFIC_LOAD_LOW:
                /* avoid antenna B unless MIMO */
                if (tbl->action == IWL_MIMO2_SWITCH_SISO_B ||
                    tbl->action == IWL_MIMO2_SWITCH_SISO_C)
                        tbl->action = IWL_MIMO2_SWITCH_SISO_A;
                break;
        default:
                IWL_ERR(mvm, "Invalid BT load %d",
                        BT_MBOX_MSG(&mvm->last_bt_notif, 3, TRAFFIC_LOAD));
                break;
        }

        start_action = tbl->action;
        while (1) {
                lq_sta->action_counter++;
                switch (tbl->action) {
                case IWL_MIMO2_SWITCH_ANTENNA1:
                case IWL_MIMO2_SWITCH_ANTENNA2:
                        IWL_DEBUG_RATE(mvm, "LQ: MIMO2 toggle Antennas\n");

                        if (tx_chains_num <= 2)
                                break;

                        if (window->success_ratio >= IWL_RS_GOOD_RATIO)
                                break;

                        memcpy(search_tbl, tbl, sz);
                        if (rs_toggle_antenna(valid_tx_ant,
                                              &search_tbl->current_rate,
                                              search_tbl)) {
                                update_search_tbl_counter = 1;
                                goto out;
                        }
                        break;
                case IWL_MIMO2_SWITCH_SISO_A:
                case IWL_MIMO2_SWITCH_SISO_B:
                case IWL_MIMO2_SWITCH_SISO_C:
                        IWL_DEBUG_RATE(mvm, "LQ: MIMO2 switch to SISO\n");

                        /* Set up new search table for SISO */
                        memcpy(search_tbl, tbl, sz);

                        if (tbl->action == IWL_MIMO2_SWITCH_SISO_A)
                                search_tbl->ant_type = ANT_A;
                        else if (tbl->action == IWL_MIMO2_SWITCH_SISO_B)
                                search_tbl->ant_type = ANT_B;
                        else
                                search_tbl->ant_type = ANT_C;

                        if (!rs_is_valid_ant(valid_tx_ant,
                                             search_tbl->ant_type))
                                break;

                        ret = rs_switch_to_siso(mvm, lq_sta, sta,
                                                 search_tbl, index);
                        if (!ret)
                                goto out;

                        break;

                case IWL_MIMO2_SWITCH_GI:
                        if (!tbl->is_ht40 && !(ht_cap->cap &
                                                IEEE80211_HT_CAP_SGI_20))
                                break;
                        if (tbl->is_ht40 && !(ht_cap->cap &
                                                IEEE80211_HT_CAP_SGI_40))
                                break;

                        IWL_DEBUG_RATE(mvm, "LQ: MIMO2 toggle SGI/NGI\n");

                        /* Set up new search table for MIMO2 */
                        memcpy(search_tbl, tbl, sz);
                        search_tbl->is_SGI = !tbl->is_SGI;
                        rs_set_expected_tpt_table(lq_sta, search_tbl);
                        /*
                         * If active table already uses the fastest possible
                         * modulation (dual stream with short guard interval),
                         * and it's working well, there's no need to look
                         * for a better type of modulation!
                         */
                        if (tbl->is_SGI) {
                                s32 tpt = lq_sta->last_tpt / 100;
                                if (tpt >= search_tbl->expected_tpt[index])
                                        break;
                        }
                        search_tbl->current_rate =
                                rate_n_flags_from_tbl(mvm, search_tbl,
                                                      index, is_green);
                        update_search_tbl_counter = 1;
                        goto out;

                case IWL_MIMO2_SWITCH_MIMO3_ABC:
                        IWL_DEBUG_RATE(mvm, "LQ: MIMO2 switch to MIMO3\n");
                        memcpy(search_tbl, tbl, sz);
                        search_tbl->is_SGI = 0;
                        search_tbl->ant_type = ANT_ABC;

                        if (!rs_is_valid_ant(valid_tx_ant,
                                             search_tbl->ant_type))
                                break;

                        ret = rs_switch_to_mimo3(mvm, lq_sta, sta,
                                                 search_tbl, index);
                        if (!ret)
                                goto out;

                        break;
                }
                tbl->action++;
                if (tbl->action > IWL_MIMO2_SWITCH_MIMO3_ABC)
                        tbl->action = IWL_MIMO2_SWITCH_ANTENNA1;

                if (tbl->action == start_action)
                        break;
        }
        search_tbl->lq_type = LQ_NONE;
        return 0;
 out:
        lq_sta->search_better_tbl = 1;
        tbl->action++;
        if (tbl->action > IWL_MIMO2_SWITCH_MIMO3_ABC)
                tbl->action = IWL_MIMO2_SWITCH_ANTENNA1;
        if (update_search_tbl_counter)
                search_tbl->action = tbl->action;

        return 0;
}

/*
 * Try to switch to new modulation mode from MIMO3
 */
static int rs_move_mimo3_to_other(struct iwl_mvm *mvm,
                                 struct iwl_lq_sta *lq_sta,
                                 struct ieee80211_sta *sta, int index)
{
        s8 is_green = lq_sta->is_green;
        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 iwl_rate_scale_data *window = &(tbl->win[index]);
        struct ieee80211_sta_ht_cap *ht_cap = &sta->ht_cap;
        u32 sz = (sizeof(struct iwl_scale_tbl_info) -
                  (sizeof(struct iwl_rate_scale_data) * IWL_RATE_COUNT));
        u8 start_action;
        u8 valid_tx_ant = iwl_fw_valid_tx_ant(mvm->fw);
        u8 tx_chains_num = num_of_ant(valid_tx_ant);
        int ret;
        u8 update_search_tbl_counter = 0;

        switch (BT_MBOX_MSG(&mvm->last_bt_notif, 3, TRAFFIC_LOAD)) {
        case IWL_BT_COEX_TRAFFIC_LOAD_NONE:
                /* nothing */
                break;
        case IWL_BT_COEX_TRAFFIC_LOAD_HIGH:
        case IWL_BT_COEX_TRAFFIC_LOAD_CONTINUOUS:
                /* avoid antenna B and MIMO */
                if (tbl->action != IWL_MIMO3_SWITCH_SISO_A)
                        tbl->action = IWL_MIMO3_SWITCH_SISO_A;
                break;
        case IWL_BT_COEX_TRAFFIC_LOAD_LOW:
                /* avoid antenna B unless MIMO */
                if (tbl->action == IWL_MIMO3_SWITCH_SISO_B ||
                    tbl->action == IWL_MIMO3_SWITCH_SISO_C)
                        tbl->action = IWL_MIMO3_SWITCH_SISO_A;
                break;
        default:
                IWL_ERR(mvm, "Invalid BT load %d",
                        BT_MBOX_MSG(&mvm->last_bt_notif, 3, TRAFFIC_LOAD));
                break;
        }

        start_action = tbl->action;
        while (1) {
                lq_sta->action_counter++;
                switch (tbl->action) {
                case IWL_MIMO3_SWITCH_ANTENNA1:
                case IWL_MIMO3_SWITCH_ANTENNA2:
                        IWL_DEBUG_RATE(mvm, "LQ: MIMO3 toggle Antennas\n");

                        if (tx_chains_num <= 3)
                                break;

                        if (window->success_ratio >= IWL_RS_GOOD_RATIO)
                                break;

                        memcpy(search_tbl, tbl, sz);
                        if (rs_toggle_antenna(valid_tx_ant,
                                              &search_tbl->current_rate,
                                              search_tbl))
                                goto out;
                        break;
                case IWL_MIMO3_SWITCH_SISO_A:
                case IWL_MIMO3_SWITCH_SISO_B:
                case IWL_MIMO3_SWITCH_SISO_C:
                        IWL_DEBUG_RATE(mvm, "LQ: MIMO3 switch to SISO\n");

                        /* Set up new search table for SISO */
                        memcpy(search_tbl, tbl, sz);

                        if (tbl->action == IWL_MIMO3_SWITCH_SISO_A)
                                search_tbl->ant_type = ANT_A;
                        else if (tbl->action == IWL_MIMO3_SWITCH_SISO_B)
                                search_tbl->ant_type = ANT_B;
                        else
                                search_tbl->ant_type = ANT_C;

                        if (!rs_is_valid_ant(valid_tx_ant,
                                             search_tbl->ant_type))
                                break;

                        ret = rs_switch_to_siso(mvm, lq_sta, sta,
                                                search_tbl, index);
                        if (!ret)
                                goto out;

                        break;

                case IWL_MIMO3_SWITCH_MIMO2_AB:
                case IWL_MIMO3_SWITCH_MIMO2_AC:
                case IWL_MIMO3_SWITCH_MIMO2_BC:
                        IWL_DEBUG_RATE(mvm, "LQ: MIMO3 switch to MIMO2\n");

                        memcpy(search_tbl, tbl, sz);
                        search_tbl->is_SGI = 0;
                        if (tbl->action == IWL_MIMO3_SWITCH_MIMO2_AB)
                                search_tbl->ant_type = ANT_AB;
                        else if (tbl->action == IWL_MIMO3_SWITCH_MIMO2_AC)
                                search_tbl->ant_type = ANT_AC;
                        else
                                search_tbl->ant_type = ANT_BC;

                        if (!rs_is_valid_ant(valid_tx_ant,
                                             search_tbl->ant_type))
                                break;

                        ret = rs_switch_to_mimo2(mvm, lq_sta, sta,
                                                 search_tbl, index);
                        if (!ret)
                                goto out;

                        break;

                case IWL_MIMO3_SWITCH_GI:
                        if (!tbl->is_ht40 && !(ht_cap->cap &
                                                IEEE80211_HT_CAP_SGI_20))
                                break;
                        if (tbl->is_ht40 && !(ht_cap->cap &
                                                IEEE80211_HT_CAP_SGI_40))
                                break;

                        IWL_DEBUG_RATE(mvm, "LQ: MIMO3 toggle SGI/NGI\n");

                        /* Set up new search table for MIMO */
                        memcpy(search_tbl, tbl, sz);
                        search_tbl->is_SGI = !tbl->is_SGI;
                        rs_set_expected_tpt_table(lq_sta, search_tbl);
                        /*
                         * If active table already uses the fastest possible
                         * modulation (dual stream with short guard interval),
                         * and it's working well, there's no need to look
                         * for a better type of modulation!
                         */
                        if (tbl->is_SGI) {
                                s32 tpt = lq_sta->last_tpt / 100;
                                if (tpt >= search_tbl->expected_tpt[index])
                                        break;
                        }
                        search_tbl->current_rate =
                                rate_n_flags_from_tbl(mvm, search_tbl,
                                                      index, is_green);
                        update_search_tbl_counter = 1;
                        goto out;
                }
                tbl->action++;
                if (tbl->action > IWL_MIMO3_SWITCH_GI)
                        tbl->action = IWL_MIMO3_SWITCH_ANTENNA1;

                if (tbl->action == start_action)
                        break;
        }
        search_tbl->lq_type = LQ_NONE;
        return 0;
 out:
        lq_sta->search_better_tbl = 1;
        tbl->action++;
        if (tbl->action > IWL_MIMO3_SWITCH_GI)
                tbl->action = IWL_MIMO3_SWITCH_ANTENNA1;
        if (update_search_tbl_counter)
                search_tbl->action = tbl->action;

        return 0;
}

/*
 * 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 i;

        int active_tbl;
        int flush_interval_passed = 0;
        struct iwl_mvm *mvm;

        mvm = lq_sta->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->stay_in_tbl) {
                /* Elapsed time using current modulation mode */
                if (lq_sta->flush_timer)
                        flush_interval_passed =
                                time_after(jiffies,
                                           (unsigned long)(lq_sta->flush_timer +
                                                IWL_RATE_SCALE_FLUSH_INTVL));

                /*
                 * 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->stay_in_tbl = 0;        /* only place reset */
                        lq_sta->total_failed = 0;
                        lq_sta->total_success = 0;
                        lq_sta->flush_timer = 0;
                /*
                 * 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");
                                for (i = 0; i < IWL_RATE_COUNT; i++)
                                        rs_rate_scale_clear_window(
                                                &(tbl->win[i]));
                        }
                }

                /* If transitioning to allow "search", reset all history
                 * bitmaps and stats in active table (this will become the new
                 * "search" table). */
                if (!lq_sta->stay_in_tbl) {
                        for (i = 0; i < IWL_RATE_COUNT; i++)
                                rs_rate_scale_clear_window(&(tbl->win[i]));
                }
        }
}

/*
 * setup rate table in uCode
 */
static void rs_update_rate_tbl(struct iwl_mvm *mvm,
                               struct iwl_lq_sta *lq_sta,
                               struct iwl_scale_tbl_info *tbl,
                               int index, u8 is_green)
{
        u32 rate;

        /* Update uCode's rate table. */
        rate = rate_n_flags_from_tbl(mvm, tbl, index, is_green);
        rs_fill_link_cmd(mvm, lq_sta, rate);
        iwl_mvm_send_lq_cmd(mvm, &lq_sta->lq, CMD_ASYNC, false);
}

/*
 * Do rate scaling and search for new modulation mode.
 */
static void rs_rate_scale_perform(struct iwl_mvm *mvm,
                                  struct sk_buff *skb,
                                  struct ieee80211_sta *sta,
                                  struct iwl_lq_sta *lq_sta)
{
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
        int low = IWL_RATE_INVALID;
        int high = IWL_RATE_INVALID;
        int index;
        int i;
        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;
        s8 scale_action = 0;
        u16 rate_mask;
        u8 update_lq = 0;
        struct iwl_scale_tbl_info *tbl, *tbl1;
        u16 rate_scale_index_msk = 0;
        u8 is_green = 0;
        u8 active_tbl = 0;
        u8 done_search = 0;
        u16 high_low;
        s32 sr;
        u8 tid = IWL_MAX_TID_COUNT;
        struct iwl_mvm_sta *sta_priv = (void *)sta->drv_priv;
        struct iwl_mvm_tid_data *tid_data;

        IWL_DEBUG_RATE(mvm, "rate scale calculate new rate for skb\n");

        /* Send management frames and NO_ACK data using lowest rate. */
        /* TODO: this could probably be improved.. */
        if (!ieee80211_is_data(hdr->frame_control) ||
            info->flags & IEEE80211_TX_CTL_NO_ACK)
                return;

        lq_sta->supp_rates = sta->supp_rates[lq_sta->band];

        tid = rs_tl_add_packet(lq_sta, hdr);
        if ((tid != IWL_MAX_TID_COUNT) &&
            (lq_sta->tx_agg_tid_en & (1 << tid))) {
                tid_data = &sta_priv->tid_data[tid];
                if (tid_data->state == IWL_AGG_OFF)
                        lq_sta->is_agg = 0;
                else
                        lq_sta->is_agg = 1;
        } else {
                lq_sta->is_agg = 0;
        }

        /*
         * 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]);
        if (is_legacy(tbl->lq_type))
                lq_sta->is_green = 0;
        else
                lq_sta->is_green = rs_use_green(sta);
        is_green = lq_sta->is_green;

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

        IWL_DEBUG_RATE(mvm, "Rate scale index %d for type %d\n", index,
                       tbl->lq_type);

        /* rates available for this association, and for modulation mode */
        rate_mask = rs_get_supported_rates(lq_sta, hdr, tbl->lq_type);

        IWL_DEBUG_RATE(mvm, "mask 0x%04X\n", rate_mask);

        /* mask with station rate restriction */
        if (is_legacy(tbl->lq_type)) {
                if (lq_sta->band == IEEE80211_BAND_5GHZ)
                        /* supp_rates has no CCK bits in A mode */
                        rate_scale_index_msk = (u16) (rate_mask &
                                (lq_sta->supp_rates << IWL_FIRST_OFDM_RATE));
                else
                        rate_scale_index_msk = (u16) (rate_mask &
                                                      lq_sta->supp_rates);

        } else {
                rate_scale_index_msk = rate_mask;
        }

        if (!rate_scale_index_msk)
                rate_scale_index_msk = rate_mask;

        if (!((1 << index) & rate_scale_index_msk)) {
                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*/
                        tbl->lq_type = LQ_NONE;
                        lq_sta->search_better_tbl = 0;
                        tbl = &(lq_sta->lq_info[lq_sta->active_tbl]);
                        /* get "active" rate info */
                        index = iwl_hwrate_to_plcp_idx(tbl->current_rate);
                        rs_update_rate_tbl(mvm, lq_sta, tbl, index, is_green);
                }
                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;
        }

        /* force user max rate if set by user */
        if ((lq_sta->max_rate_idx != -1) &&
            (lq_sta->max_rate_idx < index)) {
                index = lq_sta->max_rate_idx;
                update_lq = 1;
                window = &(tbl->win[index]);
                goto lq_update;
        }

        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_RATE_MIN_FAILURE_TH) &&
            (window->success_counter < IWL_RATE_MIN_SUCCESS_TH)) {
                IWL_DEBUG_RATE(mvm,
                               "LQ: still below TH. succ=%d total=%d for index %d\n",
                               window->success_counter, window->counter, index);

                /* 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);

                goto out;
        }
        /* Else we have enough samples; calculate estimate of
         * actual average throughput */
        if (window->average_tpt != ((window->success_ratio *
                        tbl->expected_tpt[index] + 64) / 128)) {
                IWL_ERR(mvm,
                        "expected_tpt should have been calculated by now\n");
                window->average_tpt = ((window->success_ratio *
                                        tbl->expected_tpt[index] + 64) / 128);
        }

        /* 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,
                                       "LQ: SWITCHING TO NEW TABLE suc=%d cur-tpt=%d old-tpt=%d\n",
                                       window->success_ratio,
                                       window->average_tpt,
                                       lq_sta->last_tpt);

                        if (!is_legacy(tbl->lq_type))
                                lq_sta->enable_counter = 1;

                        /* 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,
                                       "LQ: GOING BACK TO THE OLD TABLE suc=%d cur-tpt=%d old-tpt=%d\n",
                                       window->success_ratio,
                                       window->average_tpt,
                                       lq_sta->last_tpt);

                        /* Nullify "search" table */
                        tbl->lq_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 = iwl_hwrate_to_plcp_idx(tbl->current_rate);
                        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_scale_index_msk,
                                        tbl->lq_type);
        low = high_low & 0xff;
        high = (high_low >> 8) & 0xff;

        /* If user set max rate, dont allow higher than user constrain */
        if ((lq_sta->max_rate_idx != -1) &&
            (lq_sta->max_rate_idx < high))
                high = IWL_RATE_INVALID;

        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;

        scale_action = 0;

        /* Too many failures, decrease rate */
        if ((sr <= IWL_RATE_DECREASE_TH) || (current_tpt == 0)) {
                IWL_DEBUG_RATE(mvm,
                               "decrease rate because of low success_ratio\n");
                scale_action = -1;
        /* No throughput measured yet for adjacent rates; try increase. */
        } else if ((low_tpt == IWL_INVALID_VALUE) &&
                   (high_tpt == IWL_INVALID_VALUE)) {
                if (high != IWL_RATE_INVALID && sr >= IWL_RATE_INCREASE_TH)
                        scale_action = 1;
                else if (low != IWL_RATE_INVALID)
                        scale_action = 0;
        }

        /* Both adjacent throughputs are measured, but neither one has better
         * throughput; we're using the best rate, don't change it! */
        else if ((low_tpt != IWL_INVALID_VALUE) &&
                 (high_tpt != IWL_INVALID_VALUE) &&
                 (low_tpt < current_tpt) &&
                 (high_tpt < current_tpt))
                scale_action = 0;

        /* At least one adjacent rate's throughput is measured,
         * and may have better performance. */
        else {
                /* Higher adjacent rate's throughput is measured */
                if (high_tpt != IWL_INVALID_VALUE) {
                        /* Higher rate has better throughput */
                        if (high_tpt > current_tpt &&
                            sr >= IWL_RATE_INCREASE_TH) {
                                scale_action = 1;
                        } else {
                                scale_action = 0;
                        }

                /* Lower adjacent rate's throughput is measured */
                } else if (low_tpt != IWL_INVALID_VALUE) {
                        /* Lower rate has better throughput */
                        if (low_tpt > current_tpt) {
                                IWL_DEBUG_RATE(mvm,
                                               "decrease rate because of low tpt\n");
                                scale_action = -1;
                        } else if (sr >= IWL_RATE_INCREASE_TH) {
                                scale_action = 1;
                        }
                }
        }

        /* Sanity check; asked for decrease, but success rate or throughput
         * has been good at old rate.  Don't change it. */
        if ((scale_action == -1) && (low != IWL_RATE_INVALID) &&
            ((sr > IWL_RATE_HIGH_TH) ||
             (current_tpt > (100 * tbl->expected_tpt[low]))))
                scale_action = 0;

        if ((BT_MBOX_MSG(&mvm->last_bt_notif, 3, TRAFFIC_LOAD) >=
             IWL_BT_COEX_TRAFFIC_LOAD_HIGH) &&
             (is_mimo2(tbl->lq_type) || is_mimo3(tbl->lq_type))) {
                if (lq_sta->last_bt_traffic >
                    BT_MBOX_MSG(&mvm->last_bt_notif, 3, TRAFFIC_LOAD)) {
                        /*
                         * don't set scale_action, don't want to scale up if
                         * the rate scale doesn't otherwise think that is a
                         * good idea.
                         */
                } else if (lq_sta->last_bt_traffic <=
                           BT_MBOX_MSG(&mvm->last_bt_notif, 3, TRAFFIC_LOAD)) {
                        scale_action = -1;
                }
        }
        lq_sta->last_bt_traffic =
                BT_MBOX_MSG(&mvm->last_bt_notif, 3, TRAFFIC_LOAD);

        if ((BT_MBOX_MSG(&mvm->last_bt_notif, 3, TRAFFIC_LOAD) >=
             IWL_BT_COEX_TRAFFIC_LOAD_HIGH) &&
             (is_mimo2(tbl->lq_type) || is_mimo3(tbl->lq_type))) {
                /* search for a new modulation */
                rs_stay_in_table(lq_sta, true);
                goto lq_update;
        }

        switch (scale_action) {
        case -1:
                /* Decrease starting rate, update uCode's rate table */
                if (low != IWL_RATE_INVALID) {
                        update_lq = 1;
                        index = low;
                }

                break;
        case 1:
                /* Increase starting rate, update uCode's rate table */
                if (high != IWL_RATE_INVALID) {
                        update_lq = 1;
                        index = high;
                }

                break;
        case 0:
                /* No change */
        default:
                break;
        }

        IWL_DEBUG_RATE(mvm,
                       "choose rate scale index %d action %d low %d high %d type %d\n",
                       index, scale_action, low, high, tbl->lq_type);

lq_update:
        /* Replace uCode's rate table for the destination station. */
        if (update_lq)
                rs_update_rate_tbl(mvm, lq_sta, tbl, index, is_green);

        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->stay_in_tbl && window->counter) {
                /* Save current throughput to compare with "search" throughput*/
                lq_sta->last_tpt = current_tpt;

                /* Select a new "search" modulation mode to try.
                 * If one is found, set up the new "search" table. */
                if (is_legacy(tbl->lq_type))
                        rs_move_legacy_other(mvm, lq_sta, sta, index);
                else if (is_siso(tbl->lq_type))
                        rs_move_siso_to_other(mvm, lq_sta, sta, index);
                else if (is_mimo2(tbl->lq_type))
                        rs_move_mimo2_to_other(mvm, lq_sta, sta, index);
                else
                        rs_move_mimo3_to_other(mvm, lq_sta, sta, index);

                /* 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)]);
                        for (i = 0; i < IWL_RATE_COUNT; i++)
                                rs_rate_scale_clear_window(&(tbl->win[i]));

                        /* Use new "search" start rate */
                        index = iwl_hwrate_to_plcp_idx(tbl->current_rate);

                        IWL_DEBUG_RATE(mvm,
                                       "Switch current  mcs: %X index: %d\n",
                                       tbl->current_rate, index);
                        rs_fill_link_cmd(mvm, lq_sta, tbl->current_rate);
                        iwl_mvm_send_lq_cmd(mvm, &lq_sta->lq, CMD_ASYNC, false);
                } else {
                        done_search = 1;
                }
        }

        if (done_search && !lq_sta->stay_in_tbl) {
                /* 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->lq_type) && !sta->ht_cap.ht_supported &&
                    lq_sta->action_counter > tbl1->max_search) {
                        IWL_DEBUG_RATE(mvm, "LQ: STAY in legacy table\n");
                        rs_set_stay_in_table(mvm, 1, lq_sta);
                }

                /* 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->enable_counter &&
                    (lq_sta->action_counter >= tbl1->max_search)) {
                        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) {
                                        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);
                }
        }

out:
        tbl->current_rate = rate_n_flags_from_tbl(mvm, tbl, index, is_green);
        lq_sta->last_txrate_idx = index;
}

/**
 * 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 ieee80211_band band)
{
        struct iwl_scale_tbl_info *tbl;
        int rate_idx;
        int i;
        u32 rate;
        u8 use_green = rs_use_green(sta);
        u8 active_tbl = 0;
        u8 valid_tx_ant;

        if (!sta || !lq_sta)
                return;

        i = lq_sta->last_txrate_idx;

        valid_tx_ant = iwl_fw_valid_tx_ant(mvm->fw);

        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]);

        if ((i < 0) || (i >= IWL_RATE_COUNT))
                i = 0;

        rate = iwl_rates[i].plcp;
        tbl->ant_type = first_antenna(valid_tx_ant);
        rate |= tbl->ant_type << RATE_MCS_ANT_POS;

        if (i >= IWL_FIRST_CCK_RATE && i <= IWL_LAST_CCK_RATE)
                rate |= RATE_MCS_CCK_MSK;

        rs_get_tbl_info_from_mcs(rate, band, tbl, &rate_idx);
        if (!rs_is_valid_ant(valid_tx_ant, tbl->ant_type))
                rs_toggle_antenna(valid_tx_ant, &rate, tbl);

        rate = rate_n_flags_from_tbl(mvm, tbl, rate_idx, use_green);
        tbl->current_rate = rate;
        rs_set_expected_tpt_table(lq_sta, tbl);
        rs_fill_link_cmd(NULL, lq_sta, rate);
        /* TODO restore station should remember the lq cmd */
        iwl_mvm_send_lq_cmd(mvm, &lq_sta->lq, CMD_SYNC, true);
}

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 ieee80211_supported_band *sband = txrc->sband;
        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;
        int rate_idx;

        IWL_DEBUG_RATE_LIMIT(mvm, "rate scale calculate new rate for skb\n");

        /* Get max rate if user set max rate */
        if (lq_sta) {
                lq_sta->max_rate_idx = txrc->max_rate_idx;
                if ((sband->band == IEEE80211_BAND_5GHZ) &&
                    (lq_sta->max_rate_idx != -1))
                        lq_sta->max_rate_idx += IWL_FIRST_OFDM_RATE;
                if ((lq_sta->max_rate_idx < 0) ||
                    (lq_sta->max_rate_idx >= IWL_RATE_COUNT))
                        lq_sta->max_rate_idx = -1;
        }

        /* Treat uninitialized rate scaling data same as non-existing. */
        if (lq_sta && !lq_sta->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;

        rate_idx  = lq_sta->last_txrate_idx;

        if (lq_sta->last_rate_n_flags & RATE_MCS_HT_MSK) {
                rate_idx -= IWL_FIRST_OFDM_RATE;
                /* 6M and 9M shared same MCS index */
                rate_idx = (rate_idx > 0) ? (rate_idx - 1) : 0;
                if (rs_extract_rate(lq_sta->last_rate_n_flags) >=
                    IWL_RATE_MIMO3_6M_PLCP)
                        rate_idx = rate_idx + (2 * MCS_INDEX_PER_STREAM);
                else if (rs_extract_rate(lq_sta->last_rate_n_flags) >=
                         IWL_RATE_MIMO2_6M_PLCP)
                        rate_idx = rate_idx + MCS_INDEX_PER_STREAM;
                info->control.rates[0].flags = IEEE80211_TX_RC_MCS;
                if (lq_sta->last_rate_n_flags & RATE_MCS_SGI_MSK)
                        info->control.rates[0].flags |= IEEE80211_TX_RC_SHORT_GI;
                if (lq_sta->last_rate_n_flags & RATE_MCS_CHAN_WIDTH_40) /* TODO */
                        info->control.rates[0].flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
                if (lq_sta->last_rate_n_flags & RATE_HT_MCS_GF_MSK)
                        info->control.rates[0].flags |= IEEE80211_TX_RC_GREEN_FIELD;
        } else {
                /* Check for invalid rates */
                if ((rate_idx < 0) || (rate_idx >= IWL_RATE_COUNT_LEGACY) ||
                    ((sband->band == IEEE80211_BAND_5GHZ) &&
                     (rate_idx < IWL_FIRST_OFDM_RATE)))
                        rate_idx = rate_lowest_index(sband, sta);
                /* On valid 5 GHz rate, adjust index */
                else if (sband->band == IEEE80211_BAND_5GHZ)
                        rate_idx -= IWL_FIRST_OFDM_RATE;
                info->control.rates[0].flags = 0;
        }
        info->control.rates[0].idx = rate_idx;
        info->control.rates[0].count = 1;
}

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

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

        return &sta_priv->lq_sta;
}

/*
 * Called after adding a new station to initialize rate scaling
 */
void iwl_mvm_rs_rate_init(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
                          enum ieee80211_band band)
{
        int i, j;
        struct ieee80211_hw *hw = mvm->hw;
        struct ieee80211_sta_ht_cap *ht_cap = &sta->ht_cap;
        struct iwl_mvm_sta *sta_priv;
        struct iwl_lq_sta *lq_sta;
        struct ieee80211_supported_band *sband;
        unsigned long supp; /* must be unsigned long for for_each_set_bit */

        sta_priv = (struct iwl_mvm_sta *)sta->drv_priv;
        lq_sta = &sta_priv->lq_sta;
        sband = hw->wiphy->bands[band];

        lq_sta->lq.sta_id = sta_priv->sta_id;

        for (j = 0; j < LQ_SIZE; j++)
                for (i = 0; i < IWL_RATE_COUNT; i++)
                        rs_rate_scale_clear_window(&lq_sta->lq_info[j].win[i]);

        lq_sta->flush_timer = 0;
        lq_sta->supp_rates = sta->supp_rates[sband->band];
        for (j = 0; j < LQ_SIZE; j++)
                for (i = 0; i < IWL_RATE_COUNT; i++)
                        rs_rate_scale_clear_window(&lq_sta->lq_info[j].win[i]);

        IWL_DEBUG_RATE(mvm,
                       "LQ: *** rate scale station global init for station %d ***\n",
                       sta_priv->sta_id);
        /* TODO: what is a good starting rate for STA? About middle? Maybe not
         * the lowest or the highest rate.. Could consider using RSSI from
         * previous packets? Need to have IEEE 802.1X auth succeed immediately
         * after assoc.. */

        lq_sta->max_rate_idx = -1;
        lq_sta->missed_rate_counter = IWL_MISSED_RATE_MAX;
        lq_sta->is_green = rs_use_green(sta);
        lq_sta->band = sband->band;
        /*
         * active legacy rates as per supported rates bitmap
         */
        supp = sta->supp_rates[sband->band];
        lq_sta->active_legacy_rate = 0;
        for_each_set_bit(i, &supp, BITS_PER_LONG)
                lq_sta->active_legacy_rate |= BIT(sband->bitrates[i].hw_value);

        /*
         * active_siso_rate mask includes 9 MBits (bit 5), and CCK (bits 0-3),
         * supp_rates[] does not; shift to convert format, force 9 MBits off.
         */
        lq_sta->active_siso_rate = ht_cap->mcs.rx_mask[0] << 1;
        lq_sta->active_siso_rate |= ht_cap->mcs.rx_mask[0] & 0x1;
        lq_sta->active_siso_rate &= ~((u16)0x2);
        lq_sta->active_siso_rate <<= IWL_FIRST_OFDM_RATE;

        /* Same here */
        lq_sta->active_mimo2_rate = ht_cap->mcs.rx_mask[1] << 1;
        lq_sta->active_mimo2_rate |= ht_cap->mcs.rx_mask[1] & 0x1;
        lq_sta->active_mimo2_rate &= ~((u16)0x2);
        lq_sta->active_mimo2_rate <<= IWL_FIRST_OFDM_RATE;

        lq_sta->active_mimo3_rate = ht_cap->mcs.rx_mask[2] << 1;
        lq_sta->active_mimo3_rate |= ht_cap->mcs.rx_mask[2] & 0x1;
        lq_sta->active_mimo3_rate &= ~((u16)0x2);
        lq_sta->active_mimo3_rate <<= IWL_FIRST_OFDM_RATE;

        IWL_DEBUG_RATE(mvm,
                       "SISO-RATE=%X MIMO2-RATE=%X MIMO3-RATE=%X\n",
                       lq_sta->active_siso_rate,
                       lq_sta->active_mimo2_rate,
                       lq_sta->active_mimo3_rate);

        /* These values will be overridden later */
        lq_sta->lq.single_stream_ant_msk =
                first_antenna(iwl_fw_valid_tx_ant(mvm->fw));
        lq_sta->lq.dual_stream_ant_msk =
                iwl_fw_valid_tx_ant(mvm->fw) &
                ~first_antenna(iwl_fw_valid_tx_ant(mvm->fw));
        if (!lq_sta->lq.dual_stream_ant_msk) {
                lq_sta->lq.dual_stream_ant_msk = ANT_AB;
        } else if (num_of_ant(iwl_fw_valid_tx_ant(mvm->fw)) == 2) {
                lq_sta->lq.dual_stream_ant_msk =
                        iwl_fw_valid_tx_ant(mvm->fw);
        }

        /* as default allow aggregation for all tids */
        lq_sta->tx_agg_tid_en = IWL_AGG_ALL_TID;
        lq_sta->drv = mvm;

        /* Set last_txrate_idx to lowest rate */
        lq_sta->last_txrate_idx = rate_lowest_index(sband, sta);
        if (sband->band == IEEE80211_BAND_5GHZ)
                lq_sta->last_txrate_idx += IWL_FIRST_OFDM_RATE;
        lq_sta->is_agg = 0;
#ifdef CONFIG_MAC80211_DEBUGFS
        lq_sta->dbg_fixed_rate = 0;
#endif

        rs_initialize_lq(mvm, sta, lq_sta, band);
}

static void rs_fill_link_cmd(struct iwl_mvm *mvm,
                             struct iwl_lq_sta *lq_sta, u32 new_rate)
{
        struct iwl_scale_tbl_info tbl_type;
        int index = 0;
        int rate_idx;
        int repeat_rate = 0;
        u8 ant_toggle_cnt = 0;
        u8 use_ht_possible = 1;
        u8 valid_tx_ant = 0;
        struct iwl_lq_cmd *lq_cmd = &lq_sta->lq;

        /* Override starting rate (index 0) if needed for debug purposes */
        rs_dbgfs_set_mcs(lq_sta, &new_rate, index);

        /* Interpret new_rate (rate_n_flags) */
        rs_get_tbl_info_from_mcs(new_rate, lq_sta->band,
                                 &tbl_type, &rate_idx);

        /* How many times should we repeat the initial rate? */
        if (is_legacy(tbl_type.lq_type)) {
                ant_toggle_cnt = 1;
                repeat_rate = IWL_NUMBER_TRY;
        } else {
                repeat_rate = min(IWL_HT_NUMBER_TRY,
                                  LINK_QUAL_AGG_DISABLE_START_DEF - 1);
        }

        lq_cmd->mimo_delim = is_mimo(tbl_type.lq_type) ? 1 : 0;

        /* Fill 1st table entry (index 0) */
        lq_cmd->rs_table[index] = cpu_to_le32(new_rate);

        if (num_of_ant(tbl_type.ant_type) == 1)
                lq_cmd->single_stream_ant_msk = tbl_type.ant_type;
        else if (num_of_ant(tbl_type.ant_type) == 2)
                lq_cmd->dual_stream_ant_msk = tbl_type.ant_type;
        /* otherwise we don't modify the existing value */

        index++;
        repeat_rate--;
        if (mvm)
                valid_tx_ant = iwl_fw_valid_tx_ant(mvm->fw);

        /* Fill rest of rate table */
        while (index < LINK_QUAL_MAX_RETRY_NUM) {
                /* Repeat initial/next rate.
                 * For legacy IWL_NUMBER_TRY == 1, this loop will not execute.
                 * For HT IWL_HT_NUMBER_TRY == 3, this executes twice. */
                while (repeat_rate > 0 && (index < LINK_QUAL_MAX_RETRY_NUM)) {
                        if (is_legacy(tbl_type.lq_type)) {
                                if (ant_toggle_cnt < NUM_TRY_BEFORE_ANT_TOGGLE)
                                        ant_toggle_cnt++;
                                else if (mvm &&
                                         rs_toggle_antenna(valid_tx_ant,
                                                        &new_rate, &tbl_type))
                                        ant_toggle_cnt = 1;
                        }

                        /* Override next rate if needed for debug purposes */
                        rs_dbgfs_set_mcs(lq_sta, &new_rate, index);

                        /* Fill next table entry */
                        lq_cmd->rs_table[index] =
                                        cpu_to_le32(new_rate);
                        repeat_rate--;
                        index++;
                }

                rs_get_tbl_info_from_mcs(new_rate, lq_sta->band, &tbl_type,
                                         &rate_idx);


                /* Indicate to uCode which entries might be MIMO.
                 * If initial rate was MIMO, this will finally end up
                 * as (IWL_HT_NUMBER_TRY * 2), after 2nd pass, otherwise 0. */
                if (is_mimo(tbl_type.lq_type))
                        lq_cmd->mimo_delim = index;

                /* Get next rate */
                new_rate = rs_get_lower_rate(lq_sta, &tbl_type, rate_idx,
                                             use_ht_possible);

                /* How many times should we repeat the next rate? */
                if (is_legacy(tbl_type.lq_type)) {
                        if (ant_toggle_cnt < NUM_TRY_BEFORE_ANT_TOGGLE)
                                ant_toggle_cnt++;
                        else if (mvm &&
                                 rs_toggle_antenna(valid_tx_ant,
                                                   &new_rate, &tbl_type))
                                ant_toggle_cnt = 1;

                        repeat_rate = IWL_NUMBER_TRY;
                } else {
                        repeat_rate = IWL_HT_NUMBER_TRY;
                }

                /* Don't allow HT rates after next pass.
                 * rs_get_lower_rate() will change type to LQ_A or LQ_G. */
                use_ht_possible = 0;

                /* Override next rate if needed for debug purposes */
                rs_dbgfs_set_mcs(lq_sta, &new_rate, index);

                /* Fill next table entry */
                lq_cmd->rs_table[index] = cpu_to_le32(new_rate);

                index++;
                repeat_rate--;
        }

        lq_cmd->agg_frame_cnt_limit = LINK_QUAL_AGG_FRAME_LIMIT_DEF;
        lq_cmd->agg_disable_start_th = LINK_QUAL_AGG_DISABLE_START_DEF;

        lq_cmd->agg_time_limit =
                cpu_to_le16(LINK_QUAL_AGG_TIME_LIMIT_DEF);

        /*
         * overwrite if needed, pass aggregation time limit
         * to uCode in uSec - This is racy - but heh, at least it helps...
         */
        if (mvm && BT_MBOX_MSG(&mvm->last_bt_notif, 3, TRAFFIC_LOAD) >= 2)
                lq_cmd->agg_time_limit = cpu_to_le16(1200);
}

static void *rs_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
{
        return hw->priv;
}
/* rate scale requires free function to be implemented */
static void rs_free(void *mvm_rate)
{
        return;
}

static void rs_free_sta(void *mvm_r, struct ieee80211_sta *sta,
                        void *mvm_sta)
{
        struct iwl_op_mode *op_mode __maybe_unused = mvm_r;
        struct iwl_mvm *mvm __maybe_unused = IWL_OP_MODE_GET_MVM(op_mode);

        IWL_DEBUG_RATE(mvm, "enter\n");
        IWL_DEBUG_RATE(mvm, "leave\n");
}

#ifdef CONFIG_MAC80211_DEBUGFS
static void rs_dbgfs_set_mcs(struct iwl_lq_sta *lq_sta,
                             u32 *rate_n_flags, int index)
{
        struct iwl_mvm *mvm;
        u8 valid_tx_ant;
        u8 ant_sel_tx;

        mvm = lq_sta->drv;
        valid_tx_ant = iwl_fw_valid_tx_ant(mvm->fw);
        if (lq_sta->dbg_fixed_rate) {
                ant_sel_tx =
                  ((lq_sta->dbg_fixed_rate & RATE_MCS_ANT_ABC_MSK)
                  >> RATE_MCS_ANT_POS);
                if ((valid_tx_ant & ant_sel_tx) == ant_sel_tx) {
                        *rate_n_flags = lq_sta->dbg_fixed_rate;
                        IWL_DEBUG_RATE(mvm, "Fixed rate ON\n");
                } else {
                        lq_sta->dbg_fixed_rate = 0;
                        IWL_ERR(mvm,
                                "Invalid antenna selection 0x%X, Valid is 0x%X\n",
                                ant_sel_tx, valid_tx_ant);
                        IWL_DEBUG_RATE(mvm, "Fixed rate OFF\n");
                }
        } else {
                IWL_DEBUG_RATE(mvm, "Fixed rate OFF\n");
        }
}

static ssize_t rs_sta_dbgfs_scale_table_write(struct file *file,
                        const char __user *user_buf, size_t count, loff_t *ppos)
{
        struct iwl_lq_sta *lq_sta = file->private_data;
        struct iwl_mvm *mvm;
        char buf[64];
        size_t buf_size;
        u32 parsed_rate;


        mvm = lq_sta->drv;
        memset(buf, 0, sizeof(buf));
        buf_size = min(count, sizeof(buf) -  1);
        if (copy_from_user(buf, user_buf, buf_size))
                return -EFAULT;

        if (sscanf(buf, "%x", &parsed_rate) == 1)
                lq_sta->dbg_fixed_rate = parsed_rate;
        else
                lq_sta->dbg_fixed_rate = 0;

        rs_program_fix_rate(mvm, lq_sta);

        return count;
}

static ssize_t rs_sta_dbgfs_scale_table_read(struct file *file,
                        char __user *user_buf, size_t count, loff_t *ppos)
{
        char *buff;
        int desc = 0;
        int i = 0;
        int index = 0;
        ssize_t ret;

        struct iwl_lq_sta *lq_sta = file->private_data;
        struct iwl_mvm *mvm;
        struct iwl_scale_tbl_info *tbl = &(lq_sta->lq_info[lq_sta->active_tbl]);

        mvm = lq_sta->drv;
        buff = kmalloc(1024, GFP_KERNEL);
        if (!buff)
                return -ENOMEM;

        desc += sprintf(buff+desc, "sta_id %d\n", lq_sta->lq.sta_id);
        desc += sprintf(buff+desc, "failed=%d success=%d rate=0%X\n",
                        lq_sta->total_failed, lq_sta->total_success,
                        lq_sta->active_legacy_rate);
        desc += sprintf(buff+desc, "fixed rate 0x%X\n",
                        lq_sta->dbg_fixed_rate);
        desc += sprintf(buff+desc, "valid_tx_ant %s%s%s\n",
            (iwl_fw_valid_tx_ant(mvm->fw) & ANT_A) ? "ANT_A," : "",
            (iwl_fw_valid_tx_ant(mvm->fw) & ANT_B) ? "ANT_B," : "",
            (iwl_fw_valid_tx_ant(mvm->fw) & ANT_C) ? "ANT_C" : "");
        desc += sprintf(buff+desc, "lq type %s\n",
           (is_legacy(tbl->lq_type)) ? "legacy" : "HT");
        if (is_Ht(tbl->lq_type)) {