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iwl-3945-rs.c

/******************************************************************************
 *
 * Copyright(c) 2005 - 2007 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:
 * James P. Ketrenos <ipw2100-admin@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 <net/ieee80211.h>

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

#include <linux/workqueue.h>

#define IWL 3945

#include "../net/mac80211/ieee80211_rate.h"

#include "iwlwifi.h"

#define RS_NAME "iwl-3945-rs"

struct iwl_rate_scale_data {
      u64 data;
      s32 success_counter;
      s32 success_ratio;
      s32 counter;
      s32 average_tpt;
      unsigned long stamp;
};

struct iwl_rate_scale_priv {
      spinlock_t lock;
      s32 *expected_tpt;
      unsigned long last_partial_flush;
      unsigned long last_flush;
      u32 flush_time;
      u32 last_tx_packets;
      u32 tx_packets;
      u8 tgg;
      u8 flush_pending;
      u8 start_rate;
      u8 ibss_sta_added;
      struct timer_list rate_scale_flush;
      struct iwl_rate_scale_data win[IWL_RATE_COUNT];
};

static s32 iwl_expected_tpt_g[IWL_RATE_COUNT] = {
      7, 13, 35, 58, 0, 0, 76, 104, 130, 168, 191, 202
};

static s32 iwl_expected_tpt_g_prot[IWL_RATE_COUNT] = {
      7, 13, 35, 58, 0, 0, 0, 80, 93, 113, 123, 125
};

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

static s32 iwl_expected_tpt_b[IWL_RATE_COUNT] = {
      7, 13, 35, 58, 0, 0, 0, 0, 0, 0, 0, 0
};

struct iwl_tpt_entry {
      s8 min_rssi;
      u8 index;
};

static struct iwl_tpt_entry iwl_tpt_table_a[] = {
      {-60, IWL_RATE_54M_INDEX},
      {-64, IWL_RATE_48M_INDEX},
      {-72, IWL_RATE_36M_INDEX},
      {-80, IWL_RATE_24M_INDEX},
      {-84, IWL_RATE_18M_INDEX},
      {-85, IWL_RATE_12M_INDEX},
      {-87, IWL_RATE_9M_INDEX},
      {-89, IWL_RATE_6M_INDEX}
};

static struct iwl_tpt_entry iwl_tpt_table_b[] = {
      {-86, IWL_RATE_11M_INDEX},
      {-88, IWL_RATE_5M_INDEX},
      {-90, IWL_RATE_2M_INDEX},
      {-92, IWL_RATE_1M_INDEX}

};

static struct iwl_tpt_entry iwl_tpt_table_g[] = {
      {-60, IWL_RATE_54M_INDEX},
      {-64, IWL_RATE_48M_INDEX},
      {-68, IWL_RATE_36M_INDEX},
      {-80, IWL_RATE_24M_INDEX},
      {-84, IWL_RATE_18M_INDEX},
      {-85, IWL_RATE_12M_INDEX},
      {-86, IWL_RATE_11M_INDEX},
      {-88, IWL_RATE_5M_INDEX},
      {-90, IWL_RATE_2M_INDEX},
      {-92, IWL_RATE_1M_INDEX}
};

#define IWL_RATE_MAX_WINDOW          62
#define IWL_RATE_FLUSH        (3*HZ/10)
#define IWL_RATE_WIN_FLUSH       (HZ/2)
#define IWL_RATE_HIGH_TH          11520
#define IWL_RATE_MIN_FAILURE_TH       8
#define IWL_RATE_MIN_SUCCESS_TH       8
#define IWL_RATE_DECREASE_TH       1920

static u8 iwl_get_rate_index_by_rssi(s32 rssi, u8 mode)
{
      u32 index = 0;
      u32 table_size = 0;
      struct iwl_tpt_entry *tpt_table = NULL;

      if ((rssi < IWL_MIN_RSSI_VAL) || (rssi > IWL_MAX_RSSI_VAL))
            rssi = IWL_MIN_RSSI_VAL;

      switch (mode) {
      case MODE_IEEE80211G:
            tpt_table = iwl_tpt_table_g;
            table_size = ARRAY_SIZE(iwl_tpt_table_g);
            break;

      case MODE_IEEE80211A:
            tpt_table = iwl_tpt_table_a;
            table_size = ARRAY_SIZE(iwl_tpt_table_a);
            break;

      default:
      case MODE_IEEE80211B:
            tpt_table = iwl_tpt_table_b;
            table_size = ARRAY_SIZE(iwl_tpt_table_b);
            break;
      }

      while ((index < table_size) && (rssi < tpt_table[index].min_rssi))
            index++;

      index = min(index, (table_size - 1));

      return tpt_table[index].index;
}

static void iwl_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;
}

/**
 * iwl_rate_scale_flush_windows - flush out the rate scale windows
 *
 * Returns the number of windows that have gathered data but were
 * not flushed.  If there were any that were not flushed, then
 * reschedule the rate flushing routine.
 */
static int iwl_rate_scale_flush_windows(struct iwl_rate_scale_priv *rs_priv)
{
      int unflushed = 0;
      int i;
      unsigned long flags;

      /*
       * For each rate, if we have collected data on that rate
       * and it has been more than IWL_RATE_WIN_FLUSH
       * since we flushed, clear out the gathered statistics
       */
      for (i = 0; i < IWL_RATE_COUNT; i++) {
            if (!rs_priv->win[i].counter)
                  continue;

            spin_lock_irqsave(&rs_priv->lock, flags);
            if (time_after(jiffies, rs_priv->win[i].stamp +
                         IWL_RATE_WIN_FLUSH)) {
                  IWL_DEBUG_RATE("flushing %d samples of rate "
                               "index %d\n",
                               rs_priv->win[i].counter, i);
                  iwl_clear_window(&rs_priv->win[i]);
            } else
                  unflushed++;
            spin_unlock_irqrestore(&rs_priv->lock, flags);
      }

      return unflushed;
}

#define IWL_RATE_FLUSH_MAX              5000    /* msec */
#define IWL_RATE_FLUSH_MIN              50      /* msec */

static void iwl_bg_rate_scale_flush(unsigned long data)
{
      struct iwl_rate_scale_priv *rs_priv = (void *)data;
      int unflushed = 0;
      unsigned long flags;
      u32 packet_count, duration, pps;

      IWL_DEBUG_RATE("enter\n");

      unflushed = iwl_rate_scale_flush_windows(rs_priv);

      spin_lock_irqsave(&rs_priv->lock, flags);

      rs_priv->flush_pending = 0;

      /* Number of packets Rx'd since last time this timer ran */
      packet_count = (rs_priv->tx_packets - rs_priv->last_tx_packets) + 1;

      rs_priv->last_tx_packets = rs_priv->tx_packets + 1;

      if (unflushed) {
            duration =
                jiffies_to_msecs(jiffies - rs_priv->last_partial_flush);
/*              duration = jiffies_to_msecs(rs_priv->flush_time); */

            IWL_DEBUG_RATE("Tx'd %d packets in %dms\n",
                         packet_count, duration);

            /* Determine packets per second */
            if (duration)
                  pps = (packet_count * 1000) / duration;
            else
                  pps = 0;

            if (pps) {
                  duration = IWL_RATE_FLUSH_MAX / pps;
                  if (duration < IWL_RATE_FLUSH_MIN)
                        duration = IWL_RATE_FLUSH_MIN;
            } else
                  duration = IWL_RATE_FLUSH_MAX;

            rs_priv->flush_time = msecs_to_jiffies(duration);

            IWL_DEBUG_RATE("new flush period: %d msec ave %d\n",
                         duration, packet_count);

            mod_timer(&rs_priv->rate_scale_flush, jiffies +
                    rs_priv->flush_time);

            rs_priv->last_partial_flush = jiffies;
      }

      /* If there weren't any unflushed entries, we don't schedule the timer
       * to run again */

      rs_priv->last_flush = jiffies;

      spin_unlock_irqrestore(&rs_priv->lock, flags);

      IWL_DEBUG_RATE("leave\n");
}

/**
 * iwl_collect_tx_data - Update the success/failure sliding window
 *
 * We keep a sliding window of the last 64 packets transmitted
 * at this rate.  window->data contains the bitmask of successful
 * packets.
 */
static void iwl_collect_tx_data(struct iwl_rate_scale_priv *rs_priv,
                        struct iwl_rate_scale_data *window,
                        int success, int retries)
{
      unsigned long flags;

      if (!retries) {
            IWL_DEBUG_RATE("leave: retries == 0 -- should be at least 1\n");
            return;
      }

      while (retries--) {
            spin_lock_irqsave(&rs_priv->lock, flags);

            /* If we have filled up the window then subtract one from the
             * success counter if the high-bit is counting toward
             * success */
            if (window->counter == IWL_RATE_MAX_WINDOW) {
                  if (window->data & (1ULL << (IWL_RATE_MAX_WINDOW - 1)))
                        window->success_counter--;
            } else
                  window->counter++;

            /* Slide the window to the left one bit */
            window->data = (window->data << 1);

            /* If this packet was a success then set the low bit high */
            if (success) {
                  window->success_counter++;
                  window->data |= 1;
            }

            /* window->counter can't be 0 -- it is either >0 or
             * IWL_RATE_MAX_WINDOW */
            window->success_ratio = 12800 * window->success_counter /
                window->counter;

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

            spin_unlock_irqrestore(&rs_priv->lock, flags);
      }
}

static void rs_rate_init(void *priv_rate, void *priv_sta,
                   struct ieee80211_local *local, struct sta_info *sta)
{
      int i;

      IWL_DEBUG_RATE("enter\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.. */

      for (i = IWL_RATE_COUNT - 1; i >= 0; i--) {
            if (sta->supp_rates & (1 << i)) {
                  sta->txrate = i;
                  break;
            }
      }

      sta->last_txrate = sta->txrate;

      /* For MODE_IEEE80211A mode it start at IWL_FIRST_OFDM_RATE */
        if (local->hw.conf.phymode == MODE_IEEE80211A)
                sta->last_txrate += IWL_FIRST_OFDM_RATE;

      IWL_DEBUG_RATE("leave\n");
}

static void *rs_alloc(struct ieee80211_local *local)
{
      return local->hw.priv;
}

/* rate scale requires free function to be implmented */
static void rs_free(void *priv)
{
      return;
}
static void rs_clear(void *priv)
{
      return;
}


static void *rs_alloc_sta(void *priv, gfp_t gfp)
{
      struct iwl_rate_scale_priv *rs_priv;
      int i;

      IWL_DEBUG_RATE("enter\n");

      rs_priv = kzalloc(sizeof(struct iwl_rate_scale_priv), gfp);
      if (!rs_priv) {
            IWL_DEBUG_RATE("leave: ENOMEM\n");
            return NULL;
      }

      spin_lock_init(&rs_priv->lock);

      rs_priv->start_rate = IWL_RATE_INVALID;

      /* default to just 802.11b */
      rs_priv->expected_tpt = iwl_expected_tpt_b;

      rs_priv->last_partial_flush = jiffies;
      rs_priv->last_flush = jiffies;
      rs_priv->flush_time = IWL_RATE_FLUSH;
      rs_priv->last_tx_packets = 0;
      rs_priv->ibss_sta_added = 0;

      init_timer(&rs_priv->rate_scale_flush);
      rs_priv->rate_scale_flush.data = (unsigned long)rs_priv;
      rs_priv->rate_scale_flush.function = &iwl_bg_rate_scale_flush;

      for (i = 0; i < IWL_RATE_COUNT; i++)
            iwl_clear_window(&rs_priv->win[i]);

      IWL_DEBUG_RATE("leave\n");

      return rs_priv;
}

static void rs_free_sta(void *priv, void *priv_sta)
{
      struct iwl_rate_scale_priv *rs_priv = priv_sta;

      IWL_DEBUG_RATE("enter\n");
      del_timer_sync(&rs_priv->rate_scale_flush);
      kfree(rs_priv);
      IWL_DEBUG_RATE("leave\n");
}


/*
 * get ieee prev rate from rate scale table.
 * for A and B mode we need to overright prev
 * value
 */
static int rs_adjust_next_rate(struct iwl_priv *priv, int rate)
{
      int next_rate = iwl_get_prev_ieee_rate(rate);

      switch (priv->phymode) {
      case MODE_IEEE80211A:
            if (rate == IWL_RATE_12M_INDEX)
                  next_rate = IWL_RATE_9M_INDEX;
            else if (rate == IWL_RATE_6M_INDEX)
                  next_rate = IWL_RATE_6M_INDEX;
            break;
      case MODE_IEEE80211B:
            if (rate == IWL_RATE_11M_INDEX_TABLE)
                  next_rate = IWL_RATE_5M_INDEX_TABLE;
            break;
      default:
            break;
      }

      return next_rate;
}
/**
 * rs_tx_status - Update rate control values based on Tx results
 *
 * NOTE: Uses iwl_priv->retry_rate for the # of retries attempted by
 * the hardware for each rate.
 */
static void rs_tx_status(void *priv_rate,
                   struct net_device *dev,
                   struct sk_buff *skb,
                   struct ieee80211_tx_status *tx_resp)
{
      u8 retries, current_count;
      int scale_rate_index, first_index, last_index;
      unsigned long flags;
      struct sta_info *sta;
      struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
      struct iwl_priv *priv = (struct iwl_priv *)priv_rate;
      struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
      struct iwl_rate_scale_priv *rs_priv;

      IWL_DEBUG_RATE("enter\n");

      retries = tx_resp->retry_count;

      first_index = tx_resp->control.tx_rate;
      if ((first_index < 0) || (first_index >= IWL_RATE_COUNT)) {
            IWL_DEBUG_RATE("leave: Rate out of bounds: %0x for %d\n",
                         tx_resp->control.tx_rate, first_index);
            return;
      }

      sta = sta_info_get(local, hdr->addr1);
      if (!sta || !sta->rate_ctrl_priv) {
            if (sta)
                  sta_info_put(sta);
            IWL_DEBUG_RATE("leave: No STA priv data to update!\n");
            return;
      }

      rs_priv = (void *)sta->rate_ctrl_priv;

      rs_priv->tx_packets++;

      scale_rate_index = first_index;
      last_index = first_index;

      /*
       * Update the window for each rate.  We determine which rates
       * were Tx'd based on the total number of retries vs. the number
       * of retries configured for each rate -- currently set to the
       * priv value 'retry_rate' vs. rate specific
       *
       * On exit from this while loop last_index indicates the rate
       * at which the frame was finally transmitted (or failed if no
       * ACK)
       */
      while (retries > 0) {
            if (retries < priv->retry_rate) {
                  current_count = retries;
                  last_index = scale_rate_index;
            } else {
                  current_count = priv->retry_rate;
                  last_index = rs_adjust_next_rate(priv,
                                           scale_rate_index);
            }

            /* Update this rate accounting for as many retries
             * as was used for it (per current_count) */
            iwl_collect_tx_data(rs_priv,
                            &rs_priv->win[scale_rate_index],
                            0, current_count);
            IWL_DEBUG_RATE("Update rate %d for %d retries.\n",
                         scale_rate_index, current_count);

            retries -= current_count;

            if (retries)
                  scale_rate_index =
                      rs_adjust_next_rate(priv, scale_rate_index);
      }


      /* Update the last index window with success/failure based on ACK */
      IWL_DEBUG_RATE("Update rate %d with %s.\n",
                   last_index,
                   (tx_resp->flags & IEEE80211_TX_STATUS_ACK) ?
                   "success" : "failure");
      iwl_collect_tx_data(rs_priv,
                      &rs_priv->win[last_index],
                      tx_resp->flags & IEEE80211_TX_STATUS_ACK, 1);

      /* We updated the rate scale window -- if its been more than
       * flush_time since the last run, schedule the flush
       * again */
      spin_lock_irqsave(&rs_priv->lock, flags);

      if (!rs_priv->flush_pending &&
          time_after(jiffies, rs_priv->last_partial_flush +
                   rs_priv->flush_time)) {

            rs_priv->flush_pending = 1;
            mod_timer(&rs_priv->rate_scale_flush,
                    jiffies + rs_priv->flush_time);
      }

      spin_unlock_irqrestore(&rs_priv->lock, flags);

      sta_info_put(sta);

      IWL_DEBUG_RATE("leave\n");

      return;
}

static struct ieee80211_rate *iwl_get_lowest_rate(struct ieee80211_local
                                      *local)
{
      struct ieee80211_hw_mode *mode = local->oper_hw_mode;
      int i;

      for (i = 0; i < mode->num_rates; i++) {
            struct ieee80211_rate *rate = &mode->rates[i];

            if (rate->flags & IEEE80211_RATE_SUPPORTED)
                  return rate;
      }

      return &mode->rates[0];
}

static u16 iwl_get_adjacent_rate(struct iwl_rate_scale_priv *rs_priv,
                         u8 index, u16 rate_mask, int phymode)
{
      u8 high = IWL_RATE_INVALID;
      u8 low = IWL_RATE_INVALID;

      /* 802.11A walks to the next literal adjascent rate in
       * the rate table */
      if (unlikely(phymode == MODE_IEEE80211A)) {
            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) {
            if (rs_priv->tgg)
                  low = iwl_rates[low].prev_rs_tgg;
            else
                  low = iwl_rates[low].prev_rs;
            if (low == IWL_RATE_INVALID)
                  break;
            if (rate_mask & (1 << low))
                  break;
            IWL_DEBUG_RATE("Skipping masked lower rate: %d\n", low);
      }

      high = index;
      while (high != IWL_RATE_INVALID) {
            if (rs_priv->tgg)
                  high = iwl_rates[high].next_rs_tgg;
            else
                  high = iwl_rates[high].next_rs;
            if (high == IWL_RATE_INVALID)
                  break;
            if (rate_mask & (1 << high))
                  break;
            IWL_DEBUG_RATE("Skipping masked higher rate: %d\n", high);
      }

      return (high << 8) | low;
}

/**
 * rs_get_rate - find the rate for the requested packet
 *
 * Returns the ieee80211_rate structure allocated by the driver.
 *
 * The rate control algorithm has no internal mapping between hw_mode's
 * rate ordering and the rate ordering used by the rate control algorithm.
 *
 * The rate control algorithm uses a single table of rates that goes across
 * the entire A/B/G spectrum vs. being limited to just one particular
 * hw_mode.
 *
 * As such, we can't convert the index obtained below into the hw_mode's
 * rate table and must reference the driver allocated rate table
 *
 */
static struct ieee80211_rate *rs_get_rate(void *priv_rate,
                                struct net_device *dev,
                                struct sk_buff *skb,
                                struct rate_control_extra *extra)
{
      u8 low = IWL_RATE_INVALID;
      u8 high = IWL_RATE_INVALID;
      u16 high_low;
      int index;
      struct iwl_rate_scale_priv *rs_priv;
      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;
      unsigned long flags;
      struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
      struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
      struct sta_info *sta;
      u16 fc, rate_mask;
      struct iwl_priv *priv = (struct iwl_priv *)priv_rate;
      DECLARE_MAC_BUF(mac);

      IWL_DEBUG_RATE("enter\n");

      memset(extra, 0, sizeof(*extra));

      fc = le16_to_cpu(hdr->frame_control);
      if (((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA) ||
          (is_multicast_ether_addr(hdr->addr1))) {
            /* Send management frames and broadcast/multicast data using
             * lowest rate. */
            /* TODO: this could probably be improved.. */
            IWL_DEBUG_RATE("leave: lowest rate (not data or is "
                         "multicast)\n");

            return iwl_get_lowest_rate(local);
      }

      sta = sta_info_get(local, hdr->addr1);
      if (!sta || !sta->rate_ctrl_priv) {
            IWL_DEBUG_RATE("leave: No STA priv data to update!\n");
            if (sta)
                  sta_info_put(sta);
            return NULL;
      }

      rate_mask = sta->supp_rates;
      index = min(sta->last_txrate & 0xffff, IWL_RATE_COUNT - 1);

      if (priv->phymode == (u8) MODE_IEEE80211A)
            rate_mask = rate_mask << IWL_FIRST_OFDM_RATE;

      rs_priv = (void *)sta->rate_ctrl_priv;

      if ((priv->iw_mode == IEEE80211_IF_TYPE_IBSS) &&
          !rs_priv->ibss_sta_added) {
            u8 sta_id = iwl_hw_find_station(priv, hdr->addr1);

            if (sta_id == IWL_INVALID_STATION) {
                  IWL_DEBUG_RATE("LQ: ADD station %s\n",
                               print_mac(mac, hdr->addr1));
                  sta_id = iwl_add_station(priv,
                            hdr->addr1, 0, CMD_ASYNC);
            }
            if (sta_id != IWL_INVALID_STATION)
                  rs_priv->ibss_sta_added = 1;
      }

      spin_lock_irqsave(&rs_priv->lock, flags);

      if (rs_priv->start_rate != IWL_RATE_INVALID) {
            index = rs_priv->start_rate;
            rs_priv->start_rate = IWL_RATE_INVALID;
      }

      window = &(rs_priv->win[index]);

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

      if (((fail_count <= IWL_RATE_MIN_FAILURE_TH) &&
           (window->success_counter < IWL_RATE_MIN_SUCCESS_TH))) {
            window->average_tpt = IWL_INVALID_VALUE;
            spin_unlock_irqrestore(&rs_priv->lock, flags);

            IWL_DEBUG_RATE("Invalid average_tpt on rate %d: "
                         "counter: %d, success_counter: %d, "
                         "expected_tpt is %sNULL\n",
                         index,
                         window->counter,
                         window->success_counter,
                         rs_priv->expected_tpt ? "not " : "");
            goto out;

      }

      window->average_tpt = ((window->success_ratio *
                        rs_priv->expected_tpt[index] + 64) / 128);
      current_tpt = window->average_tpt;

      high_low = iwl_get_adjacent_rate(rs_priv, index, rate_mask,
                               local->hw.conf.phymode);
      low = high_low & 0xff;
      high = (high_low >> 8) & 0xff;

      if (low != IWL_RATE_INVALID)
            low_tpt = rs_priv->win[low].average_tpt;

      if (high != IWL_RATE_INVALID)
            high_tpt = rs_priv->win[high].average_tpt;

      spin_unlock_irqrestore(&rs_priv->lock, flags);

      scale_action = 1;

      if ((window->success_ratio < IWL_RATE_DECREASE_TH) || !current_tpt) {
            IWL_DEBUG_RATE("decrease rate because of low success_ratio\n");
            scale_action = -1;
      } else if ((low_tpt == IWL_INVALID_VALUE) &&
               (high_tpt == IWL_INVALID_VALUE))
            scale_action = 1;
      else if ((low_tpt != IWL_INVALID_VALUE) &&
               (high_tpt != IWL_INVALID_VALUE)
               && (low_tpt < current_tpt)
               && (high_tpt < current_tpt)) {
            IWL_DEBUG_RATE("No action -- low [%d] & high [%d] < "
                         "current_tpt [%d]\n",
                         low_tpt, high_tpt, current_tpt);
            scale_action = 0;
      } else {
            if (high_tpt != IWL_INVALID_VALUE) {
                  if (high_tpt > current_tpt)
                        scale_action = 1;
                  else {
                        IWL_DEBUG_RATE
                            ("decrease rate because of high tpt\n");
                        scale_action = -1;
                  }
            } else if (low_tpt != IWL_INVALID_VALUE) {
                  if (low_tpt > current_tpt) {
                        IWL_DEBUG_RATE
                            ("decrease rate because of low tpt\n");
                        scale_action = -1;
                  } else
                        scale_action = 1;
            }
      }

      if ((window->success_ratio > IWL_RATE_HIGH_TH) ||
          (current_tpt > window->average_tpt)) {
            IWL_DEBUG_RATE("No action -- success_ratio [%d] > HIGH_TH or "
                         "current_tpt [%d] > average_tpt [%d]\n",
                         window->success_ratio,
                         current_tpt, window->average_tpt);
            scale_action = 0;
      }

      switch (scale_action) {
      case -1:
            if (low != IWL_RATE_INVALID)
                  index = low;
            break;

      case 1:
            if (high != IWL_RATE_INVALID)
                  index = high;

            break;

      case 0:
      default:
            break;
      }

      IWL_DEBUG_RATE("Selected %d (action %d) - low %d high %d\n",
                   index, scale_action, low, high);

 out:

      sta->last_txrate = index;
      if (priv->phymode == (u8) MODE_IEEE80211A)
            sta->txrate = sta->last_txrate - IWL_FIRST_OFDM_RATE;
      else
            sta->txrate = sta->last_txrate;

      sta_info_put(sta);

      IWL_DEBUG_RATE("leave: %d\n", index);

      return &priv->ieee_rates[index];
}

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,
      .clear = rs_clear,
      .alloc = rs_alloc,
      .free = rs_free,
      .alloc_sta = rs_alloc_sta,
      .free_sta = rs_free_sta,
};

int iwl_fill_rs_info(struct ieee80211_hw *hw, char *buf, u8 sta_id)
{
      struct ieee80211_local *local = hw_to_local(hw);
      struct iwl_priv *priv = hw->priv;
      struct iwl_rate_scale_priv *rs_priv;
      struct sta_info *sta;
      unsigned long flags;
      int count = 0, i;
      u32 samples = 0, success = 0, good = 0;
      unsigned long now = jiffies;
      u32 max_time = 0;

      sta = sta_info_get(local, priv->stations[sta_id].sta.sta.addr);
      if (!sta || !sta->rate_ctrl_priv) {
            if (sta) {
                  sta_info_put(sta);
                  IWL_DEBUG_RATE("leave - no private rate data!\n");
            } else
                  IWL_DEBUG_RATE("leave - no station!\n");
            return sprintf(buf, "station %d not found\n", sta_id);
      }

      rs_priv = (void *)sta->rate_ctrl_priv;
      spin_lock_irqsave(&rs_priv->lock, flags);
      i = IWL_RATE_54M_INDEX;
      while (1) {
            u64 mask;
            int j;

            count +=
                sprintf(&buf[count], " %2dMbs: ", iwl_rates[i].ieee / 2);

            mask = (1ULL << (IWL_RATE_MAX_WINDOW - 1));
            for (j = 0; j < IWL_RATE_MAX_WINDOW; j++, mask >>= 1)
                  buf[count++] =
                      (rs_priv->win[i].data & mask) ? '1' : '0';

            samples += rs_priv->win[i].counter;
            good += rs_priv->win[i].success_counter;
            success += rs_priv->win[i].success_counter * iwl_rates[i].ieee;

            if (rs_priv->win[i].stamp) {
                  int delta =
                      jiffies_to_msecs(now - rs_priv->win[i].stamp);

                  if (delta > max_time)
                        max_time = delta;

                  count += sprintf(&buf[count], "%5dms\n", delta);
            } else
                  buf[count++] = '\n';

            j = iwl_get_prev_ieee_rate(i);
            if (j == i)
                  break;
            i = j;
      }
      spin_unlock_irqrestore(&rs_priv->lock, flags);
      sta_info_put(sta);

      /* Display the average rate of all samples taken.
       *
       * NOTE:  We multiple # of samples by 2 since the IEEE measurement
       * added from iwl_rates is actually 2X the rate */
      if (samples)
            count += sprintf(
                  &buf[count],
                  "\nAverage rate is %3d.%02dMbs over last %4dms\n"
                  "%3d%% success (%d good packets over %d tries)\n",
                  success / (2 * samples), (success * 5 / samples) % 10,
                  max_time, good * 100 / samples, good, samples);
      else
            count += sprintf(&buf[count], "\nAverage rate: 0Mbs\n");

      return count;
}

void iwl_rate_scale_init(struct ieee80211_hw *hw, s32 sta_id)
{
      struct iwl_priv *priv = hw->priv;
      s32 rssi = 0;
      unsigned long flags;
      struct ieee80211_local *local = hw_to_local(hw);
      struct iwl_rate_scale_priv *rs_priv;
      struct sta_info *sta;

      IWL_DEBUG_RATE("enter\n");

      if (!local->rate_ctrl->ops->name ||
          strcmp(local->rate_ctrl->ops->name, RS_NAME)) {
            IWL_WARNING("iwl-3945-rs not selected as rate control algo!\n");
            IWL_DEBUG_RATE("leave - mac80211 picked the wrong RC algo.\n");
            return;
      }

      sta = sta_info_get(local, priv->stations[sta_id].sta.sta.addr);
      if (!sta || !sta->rate_ctrl_priv) {
            if (sta)
                  sta_info_put(sta);
            IWL_DEBUG_RATE("leave - no private rate data!\n");
            return;
      }

      rs_priv = (void *)sta->rate_ctrl_priv;

      spin_lock_irqsave(&rs_priv->lock, flags);

      rs_priv->tgg = 0;
      switch (priv->phymode) {
      case MODE_IEEE80211G:
            if (priv->active_rxon.flags & RXON_FLG_TGG_PROTECT_MSK) {
                  rs_priv->tgg = 1;
                  rs_priv->expected_tpt = iwl_expected_tpt_g_prot;
            } else
                  rs_priv->expected_tpt = iwl_expected_tpt_g;
            break;

      case MODE_IEEE80211A:
            rs_priv->expected_tpt = iwl_expected_tpt_a;
            break;

      default:
            IWL_WARNING("Invalid phymode.  Defaulting to 802.11b\n");
      case MODE_IEEE80211B:
            rs_priv->expected_tpt = iwl_expected_tpt_b;
            break;
      }

      sta_info_put(sta);
      spin_unlock_irqrestore(&rs_priv->lock, flags);

      rssi = priv->last_rx_rssi;
      if (rssi == 0)
            rssi = IWL_MIN_RSSI_VAL;

      IWL_DEBUG(IWL_DL_INFO | IWL_DL_RATE, "Network RSSI: %d\n", rssi);

      rs_priv->start_rate = iwl_get_rate_index_by_rssi(rssi, priv->phymode);

      IWL_DEBUG_RATE("leave: rssi %d assign rate index: "
                   "%d (plcp 0x%x)\n", rssi, rs_priv->start_rate,
                   iwl_rates[rs_priv->start_rate].plcp);
}

void iwl_rate_control_register(struct ieee80211_hw *hw)
{
      ieee80211_rate_control_register(&rs_ops);
}

void iwl_rate_control_unregister(struct ieee80211_hw *hw)
{
      ieee80211_rate_control_unregister(&rs_ops);
}



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