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iwl-agn-rs.c

/******************************************************************************
 *
 * Copyright(c) 2005 - 2009 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/wireless.h>
#include <net/mac80211.h>

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

#include <linux/workqueue.h>

#include "iwl-dev.h"
#include "iwl-sta.h"
#include "iwl-core.h"

#define RS_NAME "iwl-agn-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,
};

/**
 * struct iwl_rate_scale_data -- tx success history for one rate
 */
00081 struct iwl_rate_scale_data {
      u64 data;         /* bitmap of successful frames */
      s32 success_counter;    /* number of frames successful */
      s32 success_ratio;      /* per-cent * 128  */
      s32 counter;            /* number of frames attempted */
      s32 average_tpt;  /* success ratio * expected throughput */
      unsigned long stamp;
};

/**
 * struct iwl_scale_tbl_info -- tx params and success history for all rates
 *
 * There are two of these in struct iwl_lq_sta,
 * one for "active", and one for "search".
 */
00096 struct iwl_scale_tbl_info {
      enum iwl_table_type lq_type;
      u8 ant_type;
      u8 is_SGI;  /* 1 = short guard interval */
      u8 is_fat;  /* 1 = 40 MHz channel width */
      u8 is_dup;  /* 1 = duplicated data streams */
      u8 action;  /* change modulation; IWL_[LEGACY/SISO/MIMO]_SWITCH_* */
      u8 max_search;    /* maximun number of tables we can search */
      s32 *expected_tpt;      /* throughput metrics; expected_tpt_G, etc. */
      u32 current_rate;  /* rate_n_flags, uCode API format */
      struct iwl_rate_scale_data win[IWL_RATE_COUNT]; /* rate histories */
};

00109 struct iwl_traffic_load {
      unsigned long time_stamp;     /* age of the oldest statistics */
      u32 packet_count[TID_QUEUE_MAX_SIZE];   /* packet count in this time
                                     * slice */
      u32 total;              /* total num of packets during the
                               * last TID_MAX_TIME_DIFF */
      u8 queue_count;               /* number of queues that has
                               * been used since the last cleanup */
      u8 head;                /* start of the circular buffer */
};

/**
 * struct iwl_lq_sta -- driver's rate scaling private structure
 *
 * Pointer to this gets passed back and forth between driver and mac80211.
 */
00125 struct iwl_lq_sta {
      u8 active_tbl;          /* index of active table, range 0-1 */
      u8 enable_counter;      /* indicates HT mode */
      u8 stay_in_tbl;         /* 1: disallow, 0: allow search for new mode */
      u8 search_better_tbl;   /* 1: currently trying alternate mode */
      s32 last_tpt;

      /* The following determine when to search for a new mode */
      u32 table_count_limit;
      u32 max_failure_limit;  /* # failed frames before new search */
      u32 max_success_limit;  /* # successful frames before new search */
      u32 table_count;
      u32 total_failed; /* total failed frames, any/all rates */
      u32 total_success;      /* total successful frames, any/all rates */
      u64 flush_timer;  /* time staying in mode before new search */

      u8 action_counter;      /* # mode-switch actions tried */
      u8 is_green;
      u8 is_dup;
      enum ieee80211_band band;
      u8 ibss_sta_added;

      /* The following are bitmaps of rates; IWL_RATE_6M_MASK, etc. */
      u32 supp_rates;
      u16 active_legacy_rate;
      u16 active_siso_rate;
      u16 active_mimo2_rate;
      u16 active_mimo3_rate;
      u16 active_rate_basic;
      s8 max_rate_idx;     /* Max rate set by user */
      u8 missed_rate_counter;

      struct iwl_link_quality_cmd lq;
      struct iwl_scale_tbl_info lq_info[LQ_SIZE]; /* "active", "search" */
      struct iwl_traffic_load load[TID_MAX_LOAD_COUNT];
      u8 tx_agg_tid_en;
#ifdef CONFIG_MAC80211_DEBUGFS
      struct dentry *rs_sta_dbgfs_scale_table_file;
      struct dentry *rs_sta_dbgfs_stats_table_file;
      struct dentry *rs_sta_dbgfs_rate_scale_data_file;
      struct dentry *rs_sta_dbgfs_tx_agg_tid_en_file;
      u32 dbg_fixed_rate;
#endif
      struct iwl_priv *drv;

      /* used to be in sta_info */
      int last_txrate_idx;
      /* last tx rate_n_flags */
      u32 last_rate_n_flags;
};

static void rs_rate_scale_perform(struct iwl_priv *priv,
                           struct sk_buff *skb,
                           struct ieee80211_sta *sta,
                           struct iwl_lq_sta *lq_sta);
static void rs_fill_link_cmd(const struct iwl_priv *priv,
                       struct iwl_lq_sta *lq_sta, u32 rate_n_flags);


#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

/*
 * Expected throughput metrics for following rates:
 * 1, 2, 5.5, 11, 6, 9, 12, 18, 24, 36, 48, 54, 60 MBits
 * "G" is the only table that supports CCK (the first 4 rates).
 */

static s32 expected_tpt_A[IWL_RATE_COUNT] = {
      0, 0, 0, 0, 40, 57, 72, 98, 121, 154, 177, 186, 186
};

static s32 expected_tpt_G[IWL_RATE_COUNT] = {
      7, 13, 35, 58, 40, 57, 72, 98, 121, 154, 177, 186, 186
};

static s32 expected_tpt_siso20MHz[IWL_RATE_COUNT] = {
      0, 0, 0, 0, 42, 42, 76, 102, 124, 159, 183, 193, 202
};

static s32 expected_tpt_siso20MHzSGI[IWL_RATE_COUNT] = {
      0, 0, 0, 0, 46, 46, 82, 110, 132, 168, 192, 202, 211
};

static s32 expected_tpt_mimo2_20MHz[IWL_RATE_COUNT] = {
      0, 0, 0, 0, 74, 74, 123, 155, 179, 214, 236, 244, 251
};

static s32 expected_tpt_mimo2_20MHzSGI[IWL_RATE_COUNT] = {
      0, 0, 0, 0, 81, 81, 131, 164, 188, 222, 243, 251, 257
};

static s32 expected_tpt_siso40MHz[IWL_RATE_COUNT] = {
      0, 0, 0, 0, 77, 77, 127, 160, 184, 220, 242, 250, 257
};

static s32 expected_tpt_siso40MHzSGI[IWL_RATE_COUNT] = {
      0, 0, 0, 0, 83, 83, 135, 169, 193, 229, 250, 257, 264
};

static s32 expected_tpt_mimo2_40MHz[IWL_RATE_COUNT] = {
      0, 0, 0, 0, 123, 123, 182, 214, 235, 264, 279, 285, 289
};

static s32 expected_tpt_mimo2_40MHzSGI[IWL_RATE_COUNT] = {
      0, 0, 0, 0, 131, 131, 191, 222, 242, 270, 284, 289, 293
};

/* Expected throughput metric MIMO3 */
static s32 expected_tpt_mimo3_20MHz[IWL_RATE_COUNT] = {
      0, 0, 0, 0, 99, 99, 153, 186, 208, 239, 256, 263, 268
};

static s32 expected_tpt_mimo3_20MHzSGI[IWL_RATE_COUNT] = {
      0, 0, 0, 0, 106, 106, 162, 194, 215, 246, 262, 268, 273
};

static s32 expected_tpt_mimo3_40MHz[IWL_RATE_COUNT] = {
      0, 0, 0, 0, 152, 152, 211, 239, 255, 279, 290, 294, 297
};

static s32 expected_tpt_mimo3_40MHzSGI[IWL_RATE_COUNT] = {
      0, 0, 0, 0, 160, 160, 219, 245, 261, 284, 294, 297, 300
};

/* mbps, mcs */
const static struct iwl_rate_mcs_info iwl_rate_mcs[IWL_RATE_COUNT] = {
  {"1", ""},
  {"2", ""},
  {"5.5", ""},
  {"11", ""},
  {"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 inline u8 rs_extract_rate(u32 rate_n_flags)
{
      return (u8)(rate_n_flags & 0xFF);
}

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 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 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;
}

/*
      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 >= TID_MAX_LOAD_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 void rs_tl_turn_on_agg_for_tid(struct iwl_priv *priv,
                              struct iwl_lq_sta *lq_data, u8 tid,
                              struct ieee80211_sta *sta)
{
      if (rs_tl_get_load(lq_data, tid) > IWL_AGG_LOAD_THRESHOLD) {
            IWL_DEBUG_HT(priv, "Starting Tx agg: STA: %pM tid: %d\n",
                        sta->addr, tid);
            ieee80211_start_tx_ba_session(priv->hw, sta->addr, tid);
      }
}

static void rs_tl_turn_on_agg(struct iwl_priv *priv, u8 tid,
                        struct iwl_lq_sta *lq_data,
                        struct ieee80211_sta *sta)
{
      if ((tid < TID_MAX_LOAD_COUNT))
            rs_tl_turn_on_agg_for_tid(priv, lq_data, tid, sta);
      else if (tid == IWL_AGG_ALL_TID)
            for (tid = 0; tid < TID_MAX_LOAD_COUNT; tid++)
                  rs_tl_turn_on_agg_for_tid(priv, lq_data, tid, sta);
}

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);
}

/**
 * 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_rate_scale_data *windows,
                        int scale_index, s32 tpt, int retries,
                        int successes)
{
      struct iwl_rate_scale_data *window = NULL;
      static const u64 mask = (((u64)1) << (IWL_RATE_MAX_WINDOW - 1));
      s32 fail_count;

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

      /* Select data for current tx bit rate */
      window = &(windows[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 (retries > 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 (throw away oldest history),
             * OR in "1", and increment "success" if this
             * frame was successful. */
            window->data <<= 1;
            if (successes > 0) {
                  window->success_counter++;
                  window->data |= 0x1;
                  successes--;
            }

            retries--;
      }

      /* 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_priv *priv,
                         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(priv, "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(priv, "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_fat) {
                  if (tbl->is_dup)
                        rate_n_flags |= RATE_MCS_DUP_MSK;
                  else
                        rate_n_flags |= RATE_MCS_FAT_MSK;
            }
            if (tbl->is_SGI)
                  rate_n_flags |= RATE_MCS_SGI_MSK;

            if (use_green) {
                  rate_n_flags |= RATE_MCS_GF_MSK;
                  if (is_siso(tbl->lq_type) && tbl->is_SGI) {
                        rate_n_flags &= ~RATE_MCS_SGI_MSK;
                        IWL_ERR(priv, "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;

      *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_fat = 0;
      tbl->is_dup = 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_FAT_MSK) ||
                (rate_n_flags & RATE_MCS_DUP_MSK))
                  tbl->is_fat = 1;

            if (rate_n_flags & RATE_MCS_DUP_MSK)
                  tbl->is_dup = 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;
}

/* in 4965 we don't use greenfield at all */
static inline u8 rs_use_green(struct iwl_priv *priv,
                        struct ieee80211_conf *conf)
{
      u8 is_green;

      if ((priv->hw_rev & CSR_HW_REV_TYPE_MSK) == CSR_HW_REV_TYPE_4965)
            is_green = 0;
      else
            is_green = (conf_is_ht(conf) &&
                     priv->current_ht_config.is_green_field &&
                     !priv->current_ht_config.non_GF_STA_present);
      return is_green;
}

/**
 * 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 (hdr && is_multicast_ether_addr(hdr->addr1) &&
          lq_sta->active_rate_basic)
            return lq_sta->active_rate_basic;

      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_priv *priv, 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(priv, "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(priv, "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;

      /* 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 = ANT_A;/*FIXME:RS*/

            tbl->is_fat = 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);
}

/*
 * mac80211 sends us Tx status
 */
static void rs_tx_status(void *priv_r, struct ieee80211_supported_band *sband,
                   struct ieee80211_sta *sta, void *priv_sta,
                   struct sk_buff *skb)
{
      int status;
      u8 retries;
      int rs_index, index = 0;
      struct iwl_lq_sta *lq_sta = priv_sta;
      struct iwl_link_quality_cmd *table;
      struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
      struct iwl_priv *priv = (struct iwl_priv *)priv_r;
      struct ieee80211_hw *hw = priv->hw;
      struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
      struct iwl_rate_scale_data *window = NULL;
      struct iwl_rate_scale_data *search_win = NULL;
      u32 tx_rate;
      struct iwl_scale_tbl_info tbl_type;
      struct iwl_scale_tbl_info *curr_tbl, *search_tbl;
      u8 active_index = 0;
      s32 tpt = 0;

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

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

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

      if (info->flags & IEEE80211_TX_STAT_AMPDU)
            retries = 0;
      else
            retries = info->status.rates[0].count - 1;

      if (retries > 15)
            retries = 15;

      if ((priv->iw_mode == NL80211_IFTYPE_ADHOC) &&
          !lq_sta->ibss_sta_added)
            goto out;

      table = &lq_sta->lq;
      active_index = lq_sta->active_tbl;

      curr_tbl = &(lq_sta->lq_info[active_index]);
      search_tbl = &(lq_sta->lq_info[(1 - active_index)]);
      window = (struct iwl_rate_scale_data *)&(curr_tbl->win[0]);
      search_win = (struct iwl_rate_scale_data *)&(search_tbl->win[0]);

      /*
       * 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).
       */
      tx_rate = le32_to_cpu(table->rs_table[0].rate_n_flags);
      rs_get_tbl_info_from_mcs(tx_rate, priv->band, &tbl_type, &rs_index);
      if (priv->band == IEEE80211_BAND_5GHZ)
            rs_index -= IWL_FIRST_OFDM_RATE;

      if ((info->status.rates[0].idx < 0) ||
          (tbl_type.is_SGI != !!(info->status.rates[0].flags & IEEE80211_TX_RC_SHORT_GI)) ||
          (tbl_type.is_fat != !!(info->status.rates[0].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)) ||
          (tbl_type.is_dup != !!(info->status.rates[0].flags & IEEE80211_TX_RC_DUP_DATA)) ||
          (tbl_type.ant_type != info->antenna_sel_tx) ||
          (!!(tx_rate & RATE_MCS_HT_MSK) != !!(info->status.rates[0].flags & IEEE80211_TX_RC_MCS)) ||
          (!!(tx_rate & RATE_MCS_GF_MSK) != !!(info->status.rates[0].flags & IEEE80211_TX_RC_GREEN_FIELD)) ||
          (hw->wiphy->bands[priv->band]->bitrates[rs_index].bitrate !=
           hw->wiphy->bands[info->band]->bitrates[info->status.rates[0].idx].bitrate)) {
            IWL_DEBUG_RATE(priv, "initial rate does not match 0x%x\n", tx_rate);
            /* the last LQ command could failed so the LQ in ucode not
             * the same in driver sync up
             */
            lq_sta->missed_rate_counter++;
            if (lq_sta->missed_rate_counter > IWL_MISSED_RATE_MAX) {
                  lq_sta->missed_rate_counter = 0;
                  iwl_send_lq_cmd(priv, &lq_sta->lq, CMD_ASYNC);
            }
            goto out;
      }

      lq_sta->missed_rate_counter = 0;
      /* Update frame history window with "failure" for each Tx retry. */
      while (retries) {
            /* Look up the rate and other info used for each tx attempt.
             * Each tx attempt steps one entry deeper in the rate table. */
            tx_rate = le32_to_cpu(table->rs_table[index].rate_n_flags);
            rs_get_tbl_info_from_mcs(tx_rate, priv->band,
                                &tbl_type, &rs_index);

            /* If type matches "search" table,
             * add failure to "search" history */
            if ((tbl_type.lq_type == search_tbl->lq_type) &&
                (tbl_type.ant_type == search_tbl->ant_type) &&
                (tbl_type.is_SGI == search_tbl->is_SGI)) {
                  if (search_tbl->expected_tpt)
                        tpt = search_tbl->expected_tpt[rs_index];
                  else
                        tpt = 0;
                  rs_collect_tx_data(search_win, rs_index, tpt, 1, 0);

            /* Else if type matches "current/active" table,
             * add failure to "current/active" history */
            } else if ((tbl_type.lq_type == curr_tbl->lq_type) &&
                     (tbl_type.ant_type == curr_tbl->ant_type) &&
                     (tbl_type.is_SGI == curr_tbl->is_SGI)) {
                  if (curr_tbl->expected_tpt)
                        tpt = curr_tbl->expected_tpt[rs_index];
                  else
                        tpt = 0;
                  rs_collect_tx_data(window, rs_index, tpt, 1, 0);
            }

            /* If not searching for a new mode, increment failed counter
             * ... this helps determine when to start searching again */
            if (lq_sta->stay_in_tbl)
                  lq_sta->total_failed++;
            --retries;
            index++;

      }

      /*
       * Find (by rate) the history window to update with final Tx attempt;
       * if Tx was successful first try, use original rate,
       * else look up the rate that was, finally, successful.
       */
      tx_rate = le32_to_cpu(table->rs_table[index].rate_n_flags);
      lq_sta->last_rate_n_flags = tx_rate;
      rs_get_tbl_info_from_mcs(tx_rate, priv->band, &tbl_type, &rs_index);

      /* Update frame history window with "success" if Tx got ACKed ... */
      status = !!(info->flags & IEEE80211_TX_STAT_ACK);

      /* If type matches "search" table,
       * add final tx status to "search" history */
      if ((tbl_type.lq_type == search_tbl->lq_type) &&
          (tbl_type.ant_type == search_tbl->ant_type) &&
          (tbl_type.is_SGI == search_tbl->is_SGI)) {
            if (search_tbl->expected_tpt)
                  tpt = search_tbl->expected_tpt[rs_index];
            else
                  tpt = 0;
            if (info->flags & IEEE80211_TX_STAT_AMPDU)
                  rs_collect_tx_data(search_win, rs_index, tpt,
                                 info->status.ampdu_ack_len,
                                 info->status.ampdu_ack_map);
            else
                  rs_collect_tx_data(search_win, rs_index, tpt,
                                 1, status);
      /* Else if type matches "current/active" table,
       * add final tx status to "current/active" history */
      } else if ((tbl_type.lq_type == curr_tbl->lq_type) &&
               (tbl_type.ant_type == curr_tbl->ant_type) &&
               (tbl_type.is_SGI == curr_tbl->is_SGI)) {
            if (curr_tbl->expected_tpt)
                  tpt = curr_tbl->expected_tpt[rs_index];
            else
                  tpt = 0;
            if (info->flags & IEEE80211_TX_STAT_AMPDU)
                  rs_collect_tx_data(window, rs_index, tpt,
                                 info->status.ampdu_ack_len,
                                 info->status.ampdu_ack_map);
            else
                  rs_collect_tx_data(window, rs_index, tpt,
                                 1, status);
      }

      /* If not searching for new mode, increment success/failed counter
       * ... these help determine when to start searching again */
      if (lq_sta->stay_in_tbl) {
            if (info->flags & IEEE80211_TX_STAT_AMPDU) {
                  lq_sta->total_success += info->status.ampdu_ack_map;
                  lq_sta->total_failed +=
                       (info->status.ampdu_ack_len - info->status.ampdu_ack_map);
            } else {
                  if (status)
                        lq_sta->total_success++;
                  else
                        lq_sta->total_failed++;
            }
      }

      /* See if there's a better rate or modulation mode to try. */
      if (sta && sta->supp_rates[sband->band])
            rs_rate_scale_perform(priv, skb, sta, lq_sta);
out:
      return;
}

/*
 * 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_priv *priv, u8 is_legacy,
                         struct iwl_lq_sta *lq_sta)
{
      IWL_DEBUG_RATE(priv, "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)
{
      if (is_legacy(tbl->lq_type)) {
            if (!is_a_band(tbl->lq_type))
                  tbl->expected_tpt = expected_tpt_G;
            else
                  tbl->expected_tpt = expected_tpt_A;
      } else if (is_siso(tbl->lq_type)) {
            if (tbl->is_fat && !lq_sta->is_dup)
                  if (tbl->is_SGI)
                        tbl->expected_tpt = expected_tpt_siso40MHzSGI;
                  else
                        tbl->expected_tpt = expected_tpt_siso40MHz;
            else if (tbl->is_SGI)
                  tbl->expected_tpt = expected_tpt_siso20MHzSGI;
            else
                  tbl->expected_tpt = expected_tpt_siso20MHz;
      } else if (is_mimo2(tbl->lq_type)) {
            if (tbl->is_fat && !lq_sta->is_dup)
                  if (tbl->is_SGI)
                        tbl->expected_tpt = expected_tpt_mimo2_40MHzSGI;
                  else
                        tbl->expected_tpt = expected_tpt_mimo2_40MHz;
            else if (tbl->is_SGI)
                  tbl->expected_tpt = expected_tpt_mimo2_20MHzSGI;
            else
                  tbl->expected_tpt = expected_tpt_mimo2_20MHz;
      } else if (is_mimo3(tbl->lq_type)) {
            if (tbl->is_fat && !lq_sta->is_dup)
                  if (tbl->is_SGI)
                        tbl->expected_tpt = expected_tpt_mimo3_40MHzSGI;
                  else
                        tbl->expected_tpt = expected_tpt_mimo3_40MHz;
            else if (tbl->is_SGI)
                  tbl->expected_tpt = expected_tpt_mimo3_20MHzSGI;
            else
                  tbl->expected_tpt = expected_tpt_mimo3_20MHz;
      } else
            tbl->expected_tpt = expected_tpt_G;
}

/*
 * 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_priv *priv,
                      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;

      for (; ;) {
            high_low = rs_get_adjacent_rate(priv, 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;
}

/*
 * Set up search table for MIMO2
 */
static int rs_switch_to_mimo2(struct iwl_priv *priv,
                       struct iwl_lq_sta *lq_sta,
                       struct ieee80211_conf *conf,
                       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 (!conf_is_ht(conf) || !sta->ht_cap.ht_supported)
            return -1;

      if (((sta->ht_cap.cap & IEEE80211_HT_CAP_SM_PS) >> 2)
                                    == WLAN_HT_CAP_SM_PS_STATIC)
            return -1;

      /* Need both Tx chains/antennas to support MIMO */
      if (priv->hw_params.tx_chains_num < 2)
            return -1;

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

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

      if (iwl_is_fat_tx_allowed(priv, &sta->ht_cap))
            tbl->is_fat = 1;
      else
            tbl->is_fat = 0;

      /* FIXME: - don't toggle SGI here
      if (tbl->is_fat) {
            if (priv->current_ht_config.sgf & HT_SHORT_GI_40MHZ_ONLY)
                  tbl->is_SGI = 1;
            else
                  tbl->is_SGI = 0;
      } else if (priv->current_ht_config.sgf & HT_SHORT_GI_20MHZ_ONLY)
            tbl->is_SGI = 1;
      else
            tbl->is_SGI = 0;
      */

      rs_set_expected_tpt_table(lq_sta, tbl);

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

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

      IWL_DEBUG_RATE(priv, "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_priv *priv,
                       struct iwl_lq_sta *lq_sta,
                       struct ieee80211_conf *conf,
                       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 (!conf_is_ht(conf) || !sta->ht_cap.ht_supported)
            return -1;

      if (((sta->ht_cap.cap & IEEE80211_HT_CAP_SM_PS) >> 2)
                                    == WLAN_HT_CAP_SM_PS_STATIC)
            return -1;

      /* Need both Tx chains/antennas to support MIMO */
      if (priv->hw_params.tx_chains_num < 3)
            return -1;

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

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

      if (iwl_is_fat_tx_allowed(priv, &sta->ht_cap))
            tbl->is_fat = 1;
      else
            tbl->is_fat = 0;

      /* FIXME: - don't toggle SGI here
      if (tbl->is_fat) {
            if (priv->current_ht_config.sgf & HT_SHORT_GI_40MHZ_ONLY)
                  tbl->is_SGI = 1;
            else
                  tbl->is_SGI = 0;
      } else if (priv->current_ht_config.sgf & HT_SHORT_GI_20MHZ_ONLY)
            tbl->is_SGI = 1;
      else
            tbl->is_SGI = 0;
      */

      rs_set_expected_tpt_table(lq_sta, tbl);

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

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

      IWL_DEBUG_RATE(priv, "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_priv *priv,
                       struct iwl_lq_sta *lq_sta,
                       struct ieee80211_conf *conf,
                       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 (!conf_is_ht(conf) || !sta->ht_cap.ht_supported)
            return -1;

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

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

      if (iwl_is_fat_tx_allowed(priv, &sta->ht_cap))
            tbl->is_fat = 1;
      else
            tbl->is_fat = 0;

      /* FIXME: - don't toggle SGI here
      if (tbl->is_fat) {
            if (priv->current_ht_config.sgf & HT_SHORT_GI_40MHZ_ONLY)
                  tbl->is_SGI = 1;
            else
                  tbl->is_SGI = 0;
      } else if (priv->current_ht_config.sgf & HT_SHORT_GI_20MHZ_ONLY)
            tbl->is_SGI = 1;
      else
            tbl->is_SGI = 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(priv, lq_sta, tbl, rate_mask, index);

      IWL_DEBUG_RATE(priv, "LQ: get best rate %d mask %X\n", rate, rate_mask);
      if ((rate == IWL_RATE_INVALID) || !((1 << rate) & rate_mask)) {
            IWL_DEBUG_RATE(priv, "can not switch with index %d rate mask %x\n",
                       rate, rate_mask);
            return -1;
      }
      tbl->current_rate = rate_n_flags_from_tbl(priv, tbl, rate, is_green);
      IWL_DEBUG_RATE(priv, "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_priv *priv,
                        struct iwl_lq_sta *lq_sta,
                        struct ieee80211_conf *conf,
                        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 = tbl->action;
      u8 valid_tx_ant = priv->hw_params.valid_tx_ant;
      u8 tx_chains_num = priv->hw_params.tx_chains_num;
      int ret = 0;
      u8 update_search_tbl_counter = 0;

      for (; ;) {
            lq_sta->action_counter++;
            switch (tbl->action) {
            case IWL_LEGACY_SWITCH_ANTENNA1:
            case IWL_LEGACY_SWITCH_ANTENNA2:
                  IWL_DEBUG_RATE(priv, "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(priv, "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(priv, lq_sta, conf, 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(priv, "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(priv, lq_sta, conf, sta,
                                     search_tbl, index);
                  if (!ret) {
                        lq_sta->action_counter = 0;
                        goto out;
                  }
                  break;

            case IWL_LEGACY_SWITCH_MIMO3_ABC:
                  IWL_DEBUG_RATE(priv, "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(priv, lq_sta, conf, 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_priv *priv,
                         struct iwl_lq_sta *lq_sta,
                         struct ieee80211_conf *conf,
                         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]);
      u32 sz = (sizeof(struct iwl_scale_tbl_info) -
              (sizeof(struct iwl_rate_scale_data) * IWL_RATE_COUNT));
      u8 start_action = tbl->action;
      u8 valid_tx_ant = priv->hw_params.valid_tx_ant;
      u8 tx_chains_num = priv->hw_params.tx_chains_num;
      u8 update_search_tbl_counter = 0;
      int ret;

      for (;;) {
            lq_sta->action_counter++;
            switch (tbl->action) {
            case IWL_SISO_SWITCH_ANTENNA1:
            case IWL_SISO_SWITCH_ANTENNA2:
                  IWL_DEBUG_RATE(priv, "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)
                        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(priv, "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(priv, lq_sta, conf, sta,
                                     search_tbl, index);
                  if (!ret)
                        goto out;
                  break;
            case IWL_SISO_SWITCH_GI:
                  if (!tbl->is_fat &&
                        !(priv->current_ht_config.sgf &
                                    HT_SHORT_GI_20MHZ))
                        break;
                  if (tbl->is_fat &&
                        !(priv->current_ht_config.sgf &
                                    HT_SHORT_GI_40MHZ))
                        break;

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

                  memcpy(search_tbl, tbl, sz);
                  if (is_green) {
                        if (!tbl->is_SGI)
                              break;
                        else
                              IWL_ERR(priv,
                                    "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(priv, search_tbl,
                                          index, is_green);
                  update_search_tbl_counter = 1;
                  goto out;
            case IWL_SISO_SWITCH_MIMO3_ABC:
                  IWL_DEBUG_RATE(priv, "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(priv, lq_sta, conf, 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_priv *priv,
                         struct iwl_lq_sta *lq_sta,
                         struct ieee80211_conf *conf,
                         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]);
      u32 sz = (sizeof(struct iwl_scale_tbl_info) -
              (sizeof(struct iwl_rate_scale_data) * IWL_RATE_COUNT));
      u8 start_action = tbl->action;
      u8 valid_tx_ant = priv->hw_params.valid_tx_ant;
      u8 tx_chains_num = priv->hw_params.tx_chains_num;
      u8 update_search_tbl_counter = 0;
      int ret;

      for (;;) {
            lq_sta->action_counter++;
            switch (tbl->action) {
            case IWL_MIMO2_SWITCH_ANTENNA1:
            case IWL_MIMO2_SWITCH_ANTENNA2:
                  IWL_DEBUG_RATE(priv, "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(priv, "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(priv, lq_sta, conf, sta,
                                     search_tbl, index);
                  if (!ret)
                        goto out;

                  break;

            case IWL_MIMO2_SWITCH_GI:
                  if (!tbl->is_fat &&
                        !(priv->current_ht_config.sgf &
                                    HT_SHORT_GI_20MHZ))
                        break;
                  if (tbl->is_fat &&
                        !(priv->current_ht_config.sgf &
                                    HT_SHORT_GI_40MHZ))
                        break;

                  IWL_DEBUG_RATE(priv, "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(priv, search_tbl,
                                          index, is_green);
                  update_search_tbl_counter = 1;
                  goto out;

            case IWL_MIMO2_SWITCH_MIMO3_ABC:
                  IWL_DEBUG_RATE(priv, "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(priv, lq_sta, conf, 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_priv *priv,
                         struct iwl_lq_sta *lq_sta,
                         struct ieee80211_conf *conf,
                         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]);
      u32 sz = (sizeof(struct iwl_scale_tbl_info) -
              (sizeof(struct iwl_rate_scale_data) * IWL_RATE_COUNT));
      u8 start_action = tbl->action;
      u8 valid_tx_ant = priv->hw_params.valid_tx_ant;
      u8 tx_chains_num = priv->hw_params.tx_chains_num;
      int ret;
      u8 update_search_tbl_counter = 0;

      for (;;) {
            lq_sta->action_counter++;
            switch (tbl->action) {
            case IWL_MIMO3_SWITCH_ANTENNA1:
            case IWL_MIMO3_SWITCH_ANTENNA2:
                  IWL_DEBUG_RATE(priv, "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(priv, "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(priv, lq_sta, conf, 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(priv, "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(priv, lq_sta, conf, sta,
                                     search_tbl, index);
                  if (!ret)
                        goto out;

                  break;

            case IWL_MIMO3_SWITCH_GI:
                  if (!tbl->is_fat &&
                        !(priv->current_ht_config.sgf &
                                    HT_SHORT_GI_20MHZ))
                        break;
                  if (tbl->is_fat &&
                        !(priv->current_ht_config.sgf &
                                    HT_SHORT_GI_40MHZ))
                        break;

                  IWL_DEBUG_RATE(priv, "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(priv, 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)
{
      struct iwl_scale_tbl_info *tbl;
      int i;
      int active_tbl;
      int flush_interval_passed = 0;
      struct iwl_priv *priv;

      priv = 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 ((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(priv, "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(priv, "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]));
            }
      }
}

/*
 * Do rate scaling and search for new modulation mode.
 */
static void rs_rate_scale_perform(struct iwl_priv *priv,
                          struct sk_buff *skb,
                          struct ieee80211_sta *sta,
                          struct iwl_lq_sta *lq_sta)
{
      struct ieee80211_hw *hw = priv->hw;
      struct ieee80211_conf *conf = &hw->conf;
      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;
      u32 rate;
      u8 is_green = 0;
      u8 active_tbl = 0;
      u8 done_search = 0;
      u16 high_low;
      s32 sr;
      u8 tid = MAX_TID_COUNT;
      struct iwl_tid_data *tid_data;

      IWL_DEBUG_RATE(priv, "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;

      if (!sta || !lq_sta)
            return;

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

      tid = rs_tl_add_packet(lq_sta, hdr);

      /*
       * 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(priv, conf);
      is_green = lq_sta->is_green;

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

      IWL_DEBUG_RATE(priv, "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(priv, "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(priv, "Current Rate is not valid\n");
            return;
      }

      /* Get expected throughput table and history window for current rate */
      if (!tbl->expected_tpt) {
            IWL_ERR(priv, "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(priv, "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);

            goto out;
      }

      /* Else we have enough samples; calculate estimate of
       * actual average throughput */

      BUG_ON(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(priv, "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(priv, "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(priv, 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(priv, "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(priv,
                            "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;

      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(priv, "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) {
            rate = rate_n_flags_from_tbl(priv, tbl, index, is_green);
            rs_fill_link_cmd(priv, lq_sta, rate);
            iwl_send_lq_cmd(priv, &lq_sta->lq, CMD_ASYNC);
      }

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

      /*
       * 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(priv, lq_sta, conf, sta, index);
            else if (is_siso(tbl->lq_type))
                  rs_move_siso_to_other(priv, lq_sta, conf, sta, index);
            else if (is_mimo2(tbl->lq_type))
                  rs_move_mimo2_to_other(priv, lq_sta, conf, sta, index);
            else
                  rs_move_mimo3_to_other(priv, lq_sta, conf, 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(priv, "Switch current  mcs: %X index: %d\n",
                             tbl->current_rate, index);
                  rs_fill_link_cmd(priv, lq_sta, tbl->current_rate);
                  iwl_send_lq_cmd(priv, &lq_sta->lq, CMD_ASYNC);
            } 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) && !conf_is_ht(conf) &&
                lq_sta->action_counter > tbl1->max_search) {
                  IWL_DEBUG_RATE(priv, "LQ: STAY in legacy table\n");
                  rs_set_stay_in_table(priv, 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 != MAX_TID_COUNT)) {
                        tid_data =
                           &priv->stations[lq_sta->lq.sta_id].tid[tid];
                        if (tid_data->agg.state == IWL_AGG_OFF) {
                              IWL_DEBUG_RATE(priv,
                                           "try to aggregate tid %d\n",
                                           tid);
                              rs_tl_turn_on_agg(priv, tid,
                                            lq_sta, sta);
                        }
                  }
                  rs_set_stay_in_table(priv, 0, lq_sta);
            }
      }

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

      return;
}


static void rs_initialize_lq(struct iwl_priv *priv,
                       struct ieee80211_conf *conf,
                       struct ieee80211_sta *sta,
                       struct iwl_lq_sta *lq_sta)
{
      struct iwl_scale_tbl_info *tbl;
      int rate_idx;
      int i;
      u32 rate;
      u8 use_green = rs_use_green(priv, conf);
      u8 active_tbl = 0;
      u8 valid_tx_ant;

      if (!sta || !lq_sta)
            goto out;

      i = lq_sta->last_txrate_idx;

      if ((lq_sta->lq.sta_id == 0xff) &&
          (priv->iw_mode == NL80211_IFTYPE_ADHOC))
            goto out;

      valid_tx_ant = priv->hw_params.valid_tx_ant;

      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, priv->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(priv, 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);
      iwl_send_lq_cmd(priv, &lq_sta->lq, CMD_ASYNC);
 out:
      return;
}

static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta, void *priv_sta,
                  struct ieee80211_tx_rate_control *txrc)
{

      struct sk_buff *skb = txrc->skb;
      struct ieee80211_supported_band *sband = txrc->sband;
      struct iwl_priv *priv = (struct iwl_priv *)priv_r;
      struct ieee80211_conf *conf = &priv->hw->conf;
      struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
      struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
      struct iwl_lq_sta *lq_sta = priv_sta;
      int rate_idx;
      u64 mask_bit = 0;

      IWL_DEBUG_RATE_LIMIT(priv, "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;
      }

      if (sta)
            mask_bit = sta->supp_rates[sband->band];

      /* Send management frames and NO_ACK data using lowest rate. */
      if (!ieee80211_is_data(hdr->frame_control) ||
          info->flags & IEEE80211_TX_CTL_NO_ACK || !sta || !lq_sta) {
            if (!mask_bit)
                  info->control.rates[0].idx =
                              rate_lowest_index(sband, NULL);
            else
                  info->control.rates[0].idx =
                              rate_lowest_index(sband, sta);
            if (info->flags & IEEE80211_TX_CTL_NO_ACK)
                  info->control.rates[0].count = 1;
            return;
      }

      rate_idx  = lq_sta->last_txrate_idx;

      if ((priv->iw_mode == NL80211_IFTYPE_ADHOC) &&
          !lq_sta->ibss_sta_added) {
            u8 sta_id = iwl_find_station(priv, hdr->addr1);

            if (sta_id == IWL_INVALID_STATION) {
                  IWL_DEBUG_RATE(priv, "LQ: ADD station %pM\n",
                               hdr->addr1);
                  sta_id = iwl_add_station(priv, hdr->addr1,
                                    false, CMD_ASYNC, NULL);
            }
            if ((sta_id != IWL_INVALID_STATION)) {
                  lq_sta->lq.sta_id = sta_id;
                  lq_sta->lq.rs_table[0].rate_n_flags = 0;
                  lq_sta->ibss_sta_added = 1;
                  rs_initialize_lq(priv, conf, sta, lq_sta);
            }
      }

      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_DUP_MSK)
                  info->control.rates[0].flags |= IEEE80211_TX_RC_DUP_DATA;
            if (lq_sta->last_rate_n_flags & RATE_MCS_FAT_MSK)
                  info->control.rates[0].flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
            if (lq_sta->last_rate_n_flags & RATE_MCS_GF_MSK)
                  info->control.rates[0].flags |= IEEE80211_TX_RC_GREEN_FIELD;
      } else {
            if (rate_idx < 0 || rate_idx > IWL_RATE_COUNT)
                  rate_idx = rate_lowest_index(sband, sta);
            else if (sband->band == IEEE80211_BAND_5GHZ)
                  rate_idx -= IWL_FIRST_OFDM_RATE;
      }
      info->control.rates[0].idx = rate_idx;

}

static void *rs_alloc_sta(void *priv_rate, struct ieee80211_sta *sta,
                    gfp_t gfp)
{
      struct iwl_lq_sta *lq_sta;
      struct iwl_priv *priv;
      int i, j;

      priv = (struct iwl_priv *)priv_rate;
      IWL_DEBUG_RATE(priv, "create station rate scale window\n");

      lq_sta = kzalloc(sizeof(struct iwl_lq_sta), gfp);

      if (lq_sta == NULL)
            return NULL;
      lq_sta->lq.sta_id = 0xff;


      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]);

      return lq_sta;
}

static void rs_rate_init(void *priv_r, struct ieee80211_supported_band *sband,
                   struct ieee80211_sta *sta, void *priv_sta)
{
      int i, j;
      struct iwl_priv *priv = (struct iwl_priv *)priv_r;
      struct ieee80211_conf *conf = &priv->hw->conf;
      struct iwl_lq_sta *lq_sta = priv_sta;
      u16 mask_bit = 0;
      int count;
      int start_rate = 0;

      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(priv, "LQ: *** rate scale station global init ***\n");
      /* 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->ibss_sta_added = 0;
      if (priv->iw_mode == NL80211_IFTYPE_AP) {
            u8 sta_id = iwl_find_station(priv,
                                                sta->addr);

            /* for IBSS the call are from tasklet */
            IWL_DEBUG_RATE(priv, "LQ: ADD station %pM\n", sta->addr);

            if (sta_id == IWL_INVALID_STATION) {
                  IWL_DEBUG_RATE(priv, "LQ: ADD station %pM\n", sta->addr);
                  sta_id = iwl_add_station(priv, sta->addr, false,
                                    CMD_ASYNC, NULL);
            }
            if ((sta_id != IWL_INVALID_STATION)) {
                  lq_sta->lq.sta_id = sta_id;
                  lq_sta->lq.rs_table[0].rate_n_flags = 0;
            }
            /* FIXME: this is w/a remove it later */
            priv->assoc_station_added = 1;
      }

      lq_sta->is_dup = 0;
      lq_sta->max_rate_idx = -1;
      lq_sta->missed_rate_counter = IWL_MISSED_RATE_MAX;
      lq_sta->is_green = rs_use_green(priv, conf);
      lq_sta->active_legacy_rate = priv->active_rate & ~(0x1000);
      lq_sta->active_rate_basic = priv->active_rate_basic;
      lq_sta->band = priv->band;
      /*
       * 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 = sta->ht_cap.mcs.rx_mask[0] << 1;
      lq_sta->active_siso_rate |= sta->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 = sta->ht_cap.mcs.rx_mask[1] << 1;
      lq_sta->active_mimo2_rate |= sta->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 = sta->ht_cap.mcs.rx_mask[2] << 1;
      lq_sta->active_mimo3_rate |= sta->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(priv, "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.general_params.single_stream_ant_msk = ANT_A;
      lq_sta->lq.general_params.dual_stream_ant_msk = ANT_AB;

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

      /* Find highest tx rate supported by hardware and destination station */
      mask_bit = sta->supp_rates[sband->band];
      count = sband->n_bitrates;
      if (sband->band == IEEE80211_BAND_5GHZ) {
            count += IWL_FIRST_OFDM_RATE;
            start_rate = IWL_FIRST_OFDM_RATE;
            mask_bit <<= IWL_FIRST_OFDM_RATE;
      }

      mask_bit = mask_bit & lq_sta->active_legacy_rate;
      lq_sta->last_txrate_idx = 4;
      for (i = start_rate; i < count; i++)
            if (mask_bit & BIT(i))
                  lq_sta->last_txrate_idx = i;

      rs_initialize_lq(priv, conf, sta, lq_sta);
}

static void rs_fill_link_cmd(const struct iwl_priv *priv,
                       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_link_quality_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) */
      memset(&tbl_type, 0, sizeof(tbl_type));
      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 = IWL_HT_NUMBER_TRY;
      }

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

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

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

      index++;
      repeat_rate--;

      if (priv)
            valid_tx_ant = priv->hw_params.valid_tx_ant;

      /* 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 (priv &&
                               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].rate_n_flags =
                              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->general_params.mimo_delimiter = 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 (priv &&
                         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].rate_n_flags = cpu_to_le32(new_rate);

            index++;
            repeat_rate--;
      }

      lq_cmd->agg_params.agg_frame_cnt_limit = LINK_QUAL_AGG_FRAME_LIMIT_MAX;
      lq_cmd->agg_params.agg_dis_start_th = LINK_QUAL_AGG_DISABLE_START_DEF;
      lq_cmd->agg_params.agg_time_limit =
            cpu_to_le16(LINK_QUAL_AGG_TIME_LIMIT_DEF);
}

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 *priv_rate)
{
      return;
}

static void rs_free_sta(void *priv_r, struct ieee80211_sta *sta,
                  void *priv_sta)
{
      struct iwl_lq_sta *lq_sta = priv_sta;
      struct iwl_priv *priv __maybe_unused = priv_r;

      IWL_DEBUG_RATE(priv, "enter\n");
      kfree(lq_sta);
      IWL_DEBUG_RATE(priv, "leave\n");
}


#ifdef CONFIG_MAC80211_DEBUGFS
static int open_file_generic(struct inode *inode, struct file *file)
{
      file->private_data = inode->i_private;
      return 0;
}
static void rs_dbgfs_set_mcs(struct iwl_lq_sta *lq_sta,
                       u32 *rate_n_flags, int index)
{
      struct iwl_priv *priv;
      u8 valid_tx_ant;
      u8 ant_sel_tx;

      priv = lq_sta->drv;
      valid_tx_ant = priv->hw_params.valid_tx_ant;
      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(priv, "Fixed rate ON\n");
            } else {
                  lq_sta->dbg_fixed_rate = 0;
                  IWL_ERR(priv,
                      "Invalid antenna selection 0x%X, Valid is 0x%X\n",
                      ant_sel_tx, valid_tx_ant);
                  IWL_DEBUG_RATE(priv, "Fixed rate OFF\n");
            }
      } else {
            IWL_DEBUG_RATE(priv, "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_priv *priv;
      char buf[64];
      int buf_size;
      u32 parsed_rate;

      priv = 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;

      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(priv, "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_send_lq_cmd(lq_sta->drv, &lq_sta->lq, CMD_ASYNC);
      }

      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_priv *priv;
      struct iwl_scale_tbl_info *tbl = &(lq_sta->lq_info[lq_sta->active_tbl]);

      priv = 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",
          (priv->hw_params.valid_tx_ant & ANT_A) ? "ANT_A," : "",
          (priv->hw_params.valid_tx_ant & ANT_B) ? "ANT_B," : "",
          (priv->hw_params.valid_tx_ant & 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)) {
            desc += sprintf(buff+desc, " %s",
               (is_siso(tbl->lq_type)) ? "SISO" :
               ((is_mimo2(tbl->lq_type)) ? "MIMO2" : "MIMO3"));
               desc += sprintf(buff+desc, " %s",
               (tbl->is_fat) ? "40MHz" : "20MHz");
               desc += sprintf(buff+desc, " %s %s\n", (tbl->is_SGI) ? "SGI" : "",
               (lq_sta->is_green) ? "GF enabled" : "");
      }
      desc += sprintf(buff+desc, "last tx rate=0x%X\n",
            lq_sta->last_rate_n_flags);
      desc += sprintf(buff+desc, "general:"
            "flags=0x%X mimo-d=%d s-ant0x%x d-ant=0x%x\n",
            lq_sta->lq.general_params.flags,
            lq_sta->lq.general_params.mimo_delimiter,
            lq_sta->lq.general_params.single_stream_ant_msk,
            lq_sta->lq.general_params.dual_stream_ant_msk);

      desc += sprintf(buff+desc, "agg:"
                  "time_limit=%d dist_start_th=%d frame_cnt_limit=%d\n",
                  le16_to_cpu(lq_sta->lq.agg_params.agg_time_limit),
                  lq_sta->lq.agg_params.agg_dis_start_th,
                  lq_sta->lq.agg_params.agg_frame_cnt_limit);

      desc += sprintf(buff+desc,
                  "Start idx [0]=0x%x [1]=0x%x [2]=0x%x [3]=0x%x\n",
                  lq_sta->lq.general_params.start_rate_index[0],
                  lq_sta->lq.general_params.start_rate_index[1],
                  lq_sta->lq.general_params.start_rate_index[2],
                  lq_sta->lq.general_params.start_rate_index[3]);

      for (i = 0; i < LINK_QUAL_MAX_RETRY_NUM; i++) {
            index = iwl_hwrate_to_plcp_idx(
                  le32_to_cpu(lq_sta->lq.rs_table[i].rate_n_flags));
            if (is_legacy(tbl->lq_type)) {
                  desc += sprintf(buff+desc, " rate[%d] 0x%X %smbps\n",
                        i, le32_to_cpu(lq_sta->lq.rs_table[i].rate_n_flags),
                        iwl_rate_mcs[index].mbps);
            } else {
                  desc += sprintf(buff+desc, " rate[%d] 0x%X %smbps (%s)\n",
                        i, le32_to_cpu(lq_sta->lq.rs_table[i].rate_n_flags),
                        iwl_rate_mcs[index].mbps, iwl_rate_mcs[index].mcs);
            }
      }

      ret = simple_read_from_buffer(user_buf, count, ppos, buff, desc);
      kfree(buff);
      return ret;
}

static const struct file_operations rs_sta_dbgfs_scale_table_ops = {
      .write = rs_sta_dbgfs_scale_table_write,
      .read = rs_sta_dbgfs_scale_table_read,
      .open = open_file_generic,
};
static ssize_t rs_sta_dbgfs_stats_table_read(struct file *file,
                  char __user *user_buf, size_t count, loff_t *ppos)
{
      char *buff;
      int desc = 0;
      int i, j;
      ssize_t ret;

      struct iwl_lq_sta *lq_sta = file->private_data;

      buff = kmalloc(1024, GFP_KERNEL);
      if (!buff)
            return -ENOMEM;

      for (i = 0; i < LQ_SIZE; i++) {
            desc += sprintf(buff+desc, "%s type=%d SGI=%d FAT=%d DUP=%d GF=%d\n"
                        "rate=0x%X\n",
                        lq_sta->active_tbl == i ? "*" : "x",
                        lq_sta->lq_info[i].lq_type,
                        lq_sta->lq_info[i].is_SGI,
                        lq_sta->lq_info[i].is_fat,
                        lq_sta->lq_info[i].is_dup,
                        lq_sta->is_green,
                        lq_sta->lq_info[i].current_rate);
            for (j = 0; j < IWL_RATE_COUNT; j++) {
                  desc += sprintf(buff+desc,
                        "counter=%d success=%d %%=%d\n",
                        lq_sta->lq_info[i].win[j].counter,
                        lq_sta->lq_info[i].win[j].success_counter,
                        lq_sta->lq_info[i].win[j].success_ratio);
            }
      }
      ret = simple_read_from_buffer(user_buf, count, ppos, buff, desc);
      kfree(buff);
      return ret;
}

static const struct file_operations rs_sta_dbgfs_stats_table_ops = {
      .read = rs_sta_dbgfs_stats_table_read,
      .open = open_file_generic,
};

static ssize_t rs_sta_dbgfs_rate_scale_data_read(struct file *file,
                  char __user *user_buf, size_t count, loff_t *ppos)
{
      char buff[120];
      int desc = 0;
      ssize_t ret;

      struct iwl_lq_sta *lq_sta = file->private_data;
      struct iwl_priv *priv;
      struct iwl_scale_tbl_info *tbl = &lq_sta->lq_info[lq_sta->active_tbl];

      priv = lq_sta->drv;

      if (is_Ht(tbl->lq_type))
            desc += sprintf(buff+desc,
                        "Bit Rate= %d Mb/s\n",
                        tbl->expected_tpt[lq_sta->last_txrate_idx]);
      else
            desc += sprintf(buff+desc,
                        "Bit Rate= %d Mb/s\n",
                        iwl_rates[lq_sta->last_txrate_idx].ieee >> 1);
      desc += sprintf(buff+desc,
                  "Signal Level= %d dBm\tNoise Level= %d dBm\n",
                  priv->last_rx_rssi, priv->last_rx_noise);
      desc += sprintf(buff+desc,
                  "Tsf= 0x%llx\tBeacon time= 0x%08X\n",
                  priv->last_tsf, priv->last_beacon_time);

      ret = simple_read_from_buffer(user_buf, count, ppos, buff, desc);
      return ret;
}

static const struct file_operations rs_sta_dbgfs_rate_scale_data_ops = {
      .read = rs_sta_dbgfs_rate_scale_data_read,
      .open = open_file_generic,
};

static void rs_add_debugfs(void *priv, void *priv_sta,
                              struct dentry *dir)
{
      struct iwl_lq_sta *lq_sta = priv_sta;
      lq_sta->rs_sta_dbgfs_scale_table_file =
            debugfs_create_file("rate_scale_table", 0600, dir,
                        lq_sta, &rs_sta_dbgfs_scale_table_ops);
      lq_sta->rs_sta_dbgfs_stats_table_file =
            debugfs_create_file("rate_stats_table", 0600, dir,
                  lq_sta, &rs_sta_dbgfs_stats_table_ops);
      lq_sta->rs_sta_dbgfs_rate_scale_data_file =
            debugfs_create_file("rate_scale_data", 0600, dir,
                  lq_sta, &rs_sta_dbgfs_rate_scale_data_ops);
      lq_sta->rs_sta_dbgfs_tx_agg_tid_en_file =
            debugfs_create_u8("tx_agg_tid_enable", 0600, dir,
            &lq_sta->tx_agg_tid_en);

}

static void rs_remove_debugfs(void *priv, void *priv_sta)
{
      struct iwl_lq_sta *lq_sta = priv_sta;
      debugfs_remove(lq_sta->rs_sta_dbgfs_scale_table_file);
      debugfs_remove(lq_sta->rs_sta_dbgfs_stats_table_file);
      debugfs_remove(lq_sta->rs_sta_dbgfs_rate_scale_data_file);
      debugfs_remove(lq_sta->rs_sta_dbgfs_tx_agg_tid_en_file);
}
#endif

static struct rate_control_ops rs_ops = {
      .module = NULL,
      .name = RS_NAME,
      .tx_status = rs_tx_status,
      .get_rate = rs_get_rate,
      .rate_init = rs_rate_init,
      .alloc = rs_alloc,
      .free = rs_free,
      .alloc_sta = rs_alloc_sta,
      .free_sta = rs_free_sta,
#ifdef CONFIG_MAC80211_DEBUGFS
      .add_sta_debugfs = rs_add_debugfs,
      .remove_sta_debugfs = rs_remove_debugfs,
#endif
};

int iwlagn_rate_control_register(void)
{
      return ieee80211_rate_control_register(&rs_ops);
}

void iwlagn_rate_control_unregister(void)
{
      ieee80211_rate_control_unregister(&rs_ops);
}


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