iwlwifi: Fix handling of retry count of NO_ACK frames in iwl-{3945|agn}-rs
[pandora-kernel.git] / drivers / net / wireless / iwlwifi / iwl-3945-rs.c
index 21c8418..814afaf 100644 (file)
@@ -1,6 +1,6 @@
 /******************************************************************************
  *
- * Copyright(c) 2005 - 2008 Intel Corporation. All rights reserved.
+ * 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
@@ -36,6 +36,7 @@
 
 #include <linux/workqueue.h>
 
+#include "iwl-commands.h"
 #include "iwl-3945.h"
 
 #define RS_NAME "iwl-3945-rs"
@@ -51,6 +52,7 @@ struct iwl3945_rate_scale_data {
 
 struct iwl3945_rs_sta {
        spinlock_t lock;
+       struct iwl_priv *priv;
        s32 *expected_tpt;
        unsigned long last_partial_flush;
        unsigned long last_flush;
@@ -62,7 +64,7 @@ struct iwl3945_rs_sta {
        u8 start_rate;
        u8 ibss_sta_added;
        struct timer_list rate_scale_flush;
-       struct iwl3945_rate_scale_data win[IWL_RATE_COUNT];
+       struct iwl3945_rate_scale_data win[IWL_RATE_COUNT_3945];
 #ifdef CONFIG_MAC80211_DEBUGFS
        struct dentry *rs_sta_dbgfs_stats_table_file;
 #endif
@@ -71,19 +73,19 @@ struct iwl3945_rs_sta {
        int last_txrate_idx;
 };
 
-static s32 iwl3945_expected_tpt_g[IWL_RATE_COUNT] = {
+static s32 iwl3945_expected_tpt_g[IWL_RATE_COUNT_3945] = {
        7, 13, 35, 58, 0, 0, 76, 104, 130, 168, 191, 202
 };
 
-static s32 iwl3945_expected_tpt_g_prot[IWL_RATE_COUNT] = {
+static s32 iwl3945_expected_tpt_g_prot[IWL_RATE_COUNT_3945] = {
        7, 13, 35, 58, 0, 0, 0, 80, 93, 113, 123, 125
 };
 
-static s32 iwl3945_expected_tpt_a[IWL_RATE_COUNT] = {
+static s32 iwl3945_expected_tpt_a[IWL_RATE_COUNT_3945] = {
        0, 0, 0, 0, 40, 57, 72, 98, 121, 154, 177, 186
 };
 
-static s32 iwl3945_expected_tpt_b[IWL_RATE_COUNT] = {
+static s32 iwl3945_expected_tpt_b[IWL_RATE_COUNT_3945] = {
        7, 13, 35, 58, 0, 0, 0, 0, 0, 0, 0, 0
 };
 
@@ -119,12 +121,13 @@ static struct iwl3945_tpt_entry iwl3945_tpt_table_g[] = {
 #define IWL_RATE_MAX_WINDOW          62
 #define IWL_RATE_FLUSH          (3*HZ)
 #define IWL_RATE_WIN_FLUSH       (HZ/2)
-#define IWL_RATE_HIGH_TH          11520
+#define IWL39_RATE_HIGH_TH          11520
 #define IWL_SUCCESS_UP_TH         8960
 #define IWL_SUCCESS_DOWN_TH      10880
-#define IWL_RATE_MIN_FAILURE_TH       8
+#define IWL_RATE_MIN_FAILURE_TH       6
 #define IWL_RATE_MIN_SUCCESS_TH       8
 #define IWL_RATE_DECREASE_TH       1920
+#define IWL_RATE_RETRY_TH           15
 
 static u8 iwl3945_get_rate_index_by_rssi(s32 rssi, enum ieee80211_band band)
 {
@@ -165,7 +168,7 @@ static void iwl3945_clear_window(struct iwl3945_rate_scale_data *window)
        window->success_counter = 0;
        window->success_ratio = -1;
        window->counter = 0;
-       window->average_tpt = IWL_INV_TPT;
+       window->average_tpt = IWL_INVALID_VALUE;
        window->stamp = 0;
 }
 
@@ -181,20 +184,21 @@ static int iwl3945_rate_scale_flush_windows(struct iwl3945_rs_sta *rs_sta)
        int unflushed = 0;
        int i;
        unsigned long flags;
+       struct iwl_priv *priv __maybe_unused = rs_sta->priv;
 
        /*
         * 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++) {
+       for (i = 0; i < IWL_RATE_COUNT_3945; i++) {
                if (!rs_sta->win[i].counter)
                        continue;
 
                spin_lock_irqsave(&rs_sta->lock, flags);
                if (time_after(jiffies, rs_sta->win[i].stamp +
                               IWL_RATE_WIN_FLUSH)) {
-                       IWL_DEBUG_RATE("flushing %d samples of rate "
+                       IWL_DEBUG_RATE(priv, "flushing %d samples of rate "
                                       "index %d\n",
                                       rs_sta->win[i].counter, i);
                        iwl3945_clear_window(&rs_sta->win[i]);
@@ -213,11 +217,12 @@ static int iwl3945_rate_scale_flush_windows(struct iwl3945_rs_sta *rs_sta)
 static void iwl3945_bg_rate_scale_flush(unsigned long data)
 {
        struct iwl3945_rs_sta *rs_sta = (void *)data;
+       struct iwl_priv *priv __maybe_unused = rs_sta->priv;
        int unflushed = 0;
        unsigned long flags;
        u32 packet_count, duration, pps;
 
-       IWL_DEBUG_RATE("enter\n");
+       IWL_DEBUG_RATE(priv, "enter\n");
 
        unflushed = iwl3945_rate_scale_flush_windows(rs_sta);
 
@@ -232,7 +237,7 @@ static void iwl3945_bg_rate_scale_flush(unsigned long data)
                duration =
                    jiffies_to_msecs(jiffies - rs_sta->last_partial_flush);
 
-               IWL_DEBUG_RATE("Tx'd %d packets in %dms\n",
+               IWL_DEBUG_RATE(priv, "Tx'd %d packets in %dms\n",
                               packet_count, duration);
 
                /* Determine packets per second */
@@ -252,7 +257,7 @@ static void iwl3945_bg_rate_scale_flush(unsigned long data)
 
                rs_sta->flush_time = msecs_to_jiffies(duration);
 
-               IWL_DEBUG_RATE("new flush period: %d msec ave %d\n",
+               IWL_DEBUG_RATE(priv, "new flush period: %d msec ave %d\n",
                               duration, packet_count);
 
                mod_timer(&rs_sta->rate_scale_flush, jiffies +
@@ -270,7 +275,7 @@ static void iwl3945_bg_rate_scale_flush(unsigned long data)
 
        spin_unlock_irqrestore(&rs_sta->lock, flags);
 
-       IWL_DEBUG_RATE("leave\n");
+       IWL_DEBUG_RATE(priv, "leave\n");
 }
 
 /**
@@ -286,50 +291,70 @@ static void iwl3945_collect_tx_data(struct iwl3945_rs_sta *rs_sta,
 {
        unsigned long flags;
        s32 fail_count;
+       struct iwl_priv *priv __maybe_unused = rs_sta->priv;
 
        if (!retries) {
-               IWL_DEBUG_RATE("leave: retries == 0 -- should be at least 1\n");
+               IWL_DEBUG_RATE(priv, "leave: retries == 0 -- should be at least 1\n");
                return;
        }
 
        spin_lock_irqsave(&rs_sta->lock, flags);
-       while (retries--) {
 
-               /* 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)))
+       /*
+        * 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 & (1ULL << (IWL_RATE_MAX_WINDOW - 1))) {
+                               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);
+               /* Increment frames-attempted counter */
+               window->counter++;
 
-               /* If this packet was a success then set the low bit high */
-               if (success) {
+               /* Shift bitmap by one frame (throw away oldest history),
+                * OR in "1", and increment "success" if this
+                * frame was successful. */
+               window->data <<= 1;
+               if (success > 0) {
                        window->success_counter++;
-                       window->data |= 1;
+                       window->data |= 0x1;
+                       success--;
                }
 
-               /* 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;
-
+               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 *
                                rs_sta->expected_tpt[index] + 64) / 128);
        else
-               window->average_tpt = IWL_INV_TPT;
+               window->average_tpt = IWL_INVALID_VALUE;
+
+       /* Tag this window as having been updated */
+       window->stamp = jiffies;
 
        spin_unlock_irqrestore(&rs_sta->lock, flags);
 
@@ -339,10 +364,10 @@ static void rs_rate_init(void *priv_r, struct ieee80211_supported_band *sband,
                         struct ieee80211_sta *sta, void *priv_sta)
 {
        struct iwl3945_rs_sta *rs_sta = priv_sta;
-       struct iwl3945_priv *priv = (struct iwl3945_priv *)priv_r;
+       struct iwl_priv *priv = (struct iwl_priv *)priv_r;
        int i;
 
-       IWL_DEBUG_RATE("enter\n");
+       IWL_DEBUG_RATE(priv, "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
@@ -365,7 +390,7 @@ static void rs_rate_init(void *priv_r, struct ieee80211_supported_band *sband,
        }
 
 
-       IWL_DEBUG_RATE("leave\n");
+       IWL_DEBUG_RATE(priv, "leave\n");
 }
 
 static void *rs_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
@@ -379,10 +404,11 @@ static void rs_free(void *priv)
        return;
 }
 
-static void *rs_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
+static void *rs_alloc_sta(void *iwl_priv, struct ieee80211_sta *sta, gfp_t gfp)
 {
        struct iwl3945_rs_sta *rs_sta;
        struct iwl3945_sta_priv *psta = (void *) sta->drv_priv;
+       struct iwl_priv *priv = iwl_priv;
        int i;
 
        /*
@@ -390,11 +416,11 @@ static void *rs_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
         *      as well just put all the information there.
         */
 
-       IWL_DEBUG_RATE("enter\n");
+       IWL_DEBUG_RATE(priv, "enter\n");
 
        rs_sta = kzalloc(sizeof(struct iwl3945_rs_sta), gfp);
        if (!rs_sta) {
-               IWL_DEBUG_RATE("leave: ENOMEM\n");
+               IWL_DEBUG_RATE(priv, "leave: ENOMEM\n");
                return NULL;
        }
 
@@ -402,6 +428,8 @@ static void *rs_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
 
        spin_lock_init(&rs_sta->lock);
 
+       rs_sta->priv = priv;
+
        rs_sta->start_rate = IWL_RATE_INVALID;
 
        /* default to just 802.11b */
@@ -417,33 +445,34 @@ static void *rs_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
        rs_sta->rate_scale_flush.data = (unsigned long)rs_sta;
        rs_sta->rate_scale_flush.function = &iwl3945_bg_rate_scale_flush;
 
-       for (i = 0; i < IWL_RATE_COUNT; i++)
+       for (i = 0; i < IWL_RATE_COUNT_3945; i++)
                iwl3945_clear_window(&rs_sta->win[i]);
 
-       IWL_DEBUG_RATE("leave\n");
+       IWL_DEBUG_RATE(priv, "leave\n");
 
        return rs_sta;
 }
 
-static void rs_free_sta(void *priv, struct ieee80211_sta *sta,
+static void rs_free_sta(void *iwl_priv, struct ieee80211_sta *sta,
                        void *priv_sta)
 {
        struct iwl3945_sta_priv *psta = (void *) sta->drv_priv;
        struct iwl3945_rs_sta *rs_sta = priv_sta;
+       struct iwl_priv *priv __maybe_unused = rs_sta->priv;
 
        psta->rs_sta = NULL;
 
-       IWL_DEBUG_RATE("enter\n");
+       IWL_DEBUG_RATE(priv, "enter\n");
        del_timer_sync(&rs_sta->rate_scale_flush);
        kfree(rs_sta);
-       IWL_DEBUG_RATE("leave\n");
+       IWL_DEBUG_RATE(priv, "leave\n");
 }
 
 
 /**
  * rs_tx_status - Update rate control values based on Tx results
  *
- * NOTE: Uses iwl3945_priv->retry_rate for the # of retries attempted by
+ * 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 ieee80211_supported_band *sband,
@@ -453,22 +482,25 @@ static void rs_tx_status(void *priv_rate, struct ieee80211_supported_band *sband
        s8 retries = 0, current_count;
        int scale_rate_index, first_index, last_index;
        unsigned long flags;
-       struct iwl3945_priv *priv = (struct iwl3945_priv *)priv_rate;
+       struct iwl_priv *priv = (struct iwl_priv *)priv_rate;
        struct iwl3945_rs_sta *rs_sta = priv_sta;
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 
-       IWL_DEBUG_RATE("enter\n");
+       IWL_DEBUG_RATE(priv, "enter\n");
 
        retries = info->status.rates[0].count;
+       /* Sanity Check for retries */
+       if (retries > IWL_RATE_RETRY_TH)
+               retries = IWL_RATE_RETRY_TH;
 
        first_index = sband->bitrates[info->status.rates[0].idx].hw_value;
-       if ((first_index < 0) || (first_index >= IWL_RATE_COUNT)) {
-               IWL_DEBUG_RATE("leave: Rate out of bounds: %d\n", first_index);
+       if ((first_index < 0) || (first_index >= IWL_RATE_COUNT_3945)) {
+               IWL_DEBUG_RATE(priv, "leave: Rate out of bounds: %d\n", first_index);
                return;
        }
 
        if (!priv_sta) {
-               IWL_DEBUG_RATE("leave: No STA priv data to update!\n");
+               IWL_DEBUG_RATE(priv, "leave: No STA priv data to update!\n");
                return;
        }
 
@@ -502,7 +534,7 @@ static void rs_tx_status(void *priv_rate, struct ieee80211_supported_band *sband
                iwl3945_collect_tx_data(rs_sta,
                                    &rs_sta->win[scale_rate_index],
                                    0, current_count, scale_rate_index);
-               IWL_DEBUG_RATE("Update rate %d for %d retries.\n",
+               IWL_DEBUG_RATE(priv, "Update rate %d for %d retries.\n",
                               scale_rate_index, current_count);
 
                retries -= current_count;
@@ -512,7 +544,7 @@ static void rs_tx_status(void *priv_rate, struct ieee80211_supported_band *sband
 
 
        /* Update the last index window with success/failure based on ACK */
-       IWL_DEBUG_RATE("Update rate %d with %s.\n",
+       IWL_DEBUG_RATE(priv, "Update rate %d with %s.\n",
                       last_index,
                       (info->flags & IEEE80211_TX_STAT_ACK) ?
                       "success" : "failure");
@@ -537,7 +569,7 @@ static void rs_tx_status(void *priv_rate, struct ieee80211_supported_band *sband
 
        spin_unlock_irqrestore(&rs_sta->lock, flags);
 
-       IWL_DEBUG_RATE("leave\n");
+       IWL_DEBUG_RATE(priv, "leave\n");
 
        return;
 }
@@ -547,6 +579,7 @@ static u16 iwl3945_get_adjacent_rate(struct iwl3945_rs_sta *rs_sta,
 {
        u8 high = IWL_RATE_INVALID;
        u8 low = IWL_RATE_INVALID;
+       struct iwl_priv *priv __maybe_unused = rs_sta->priv;
 
        /* 802.11A walks to the next literal adjacent rate in
         * the rate table */
@@ -565,7 +598,8 @@ static u16 iwl3945_get_adjacent_rate(struct iwl3945_rs_sta *rs_sta,
 
                /* Find the next rate that is in the rate mask */
                i = index + 1;
-               for (mask = (1 << i); i < IWL_RATE_COUNT; i++, mask <<= 1) {
+               for (mask = (1 << i); i < IWL_RATE_COUNT_3945;
+                    i++, mask <<= 1) {
                        if (rate_mask & mask) {
                                high = i;
                                break;
@@ -585,7 +619,7 @@ static u16 iwl3945_get_adjacent_rate(struct iwl3945_rs_sta *rs_sta,
                        break;
                if (rate_mask & (1 << low))
                        break;
-               IWL_DEBUG_RATE("Skipping masked lower rate: %d\n", low);
+               IWL_DEBUG_RATE(priv, "Skipping masked lower rate: %d\n", low);
        }
 
        high = index;
@@ -598,7 +632,7 @@ static u16 iwl3945_get_adjacent_rate(struct iwl3945_rs_sta *rs_sta,
                        break;
                if (rate_mask & (1 << high))
                        break;
-               IWL_DEBUG_RATE("Skipping masked higher rate: %d\n", high);
+               IWL_DEBUG_RATE(priv, "Skipping masked higher rate: %d\n", high);
        }
 
        return (high << 8) | low;
@@ -631,40 +665,49 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
        int index;
        struct iwl3945_rs_sta *rs_sta = priv_sta;
        struct iwl3945_rate_scale_data *window = NULL;
-       int current_tpt = IWL_INV_TPT;
-       int low_tpt = IWL_INV_TPT;
-       int high_tpt = IWL_INV_TPT;
+       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_hdr *hdr = (struct ieee80211_hdr *)skb->data;
        u16 fc;
        u16 rate_mask = 0;
-       struct iwl3945_priv *priv = (struct iwl3945_priv *)priv_r;
+       s8 max_rate_idx = -1;
+       struct iwl_priv *priv = (struct iwl_priv *)priv_r;
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 
-       IWL_DEBUG_RATE("enter\n");
+       IWL_DEBUG_RATE(priv, "enter\n");
 
        if (sta)
                rate_mask = sta->supp_rates[sband->band];
 
-       /* Send management frames and broadcast/multicast data using lowest
-        * rate. */
+       /* Send management frames and NO_ACK data using lowest rate. */
        fc = le16_to_cpu(hdr->frame_control);
        if ((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA ||
-           is_multicast_ether_addr(hdr->addr1) ||
+           info->flags & IEEE80211_TX_CTL_NO_ACK ||
            !sta || !priv_sta) {
-               IWL_DEBUG_RATE("leave: No STA priv data to update!\n");
+               IWL_DEBUG_RATE(priv, "leave: No STA priv data to update!\n");
                if (!rate_mask)
                        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;
        }
 
-       index = min(rs_sta->last_txrate_idx & 0xffff, IWL_RATE_COUNT - 1);
+       /* get user max rate if set */
+       max_rate_idx = txrc->max_rate_idx;
+       if ((sband->band == IEEE80211_BAND_5GHZ) && (max_rate_idx != -1))
+               max_rate_idx += IWL_FIRST_OFDM_RATE;
+       if ((max_rate_idx < 0) || (max_rate_idx >= IWL_RATE_COUNT))
+               max_rate_idx = -1;
+
+       index = min(rs_sta->last_txrate_idx & 0xffff, IWL_RATE_COUNT_3945 - 1);
 
        if (sband->band == IEEE80211_BAND_5GHZ)
                rate_mask = rate_mask << IWL_FIRST_OFDM_RATE;
@@ -674,10 +717,10 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
                u8 sta_id = iwl3945_hw_find_station(priv, hdr->addr1);
 
                if (sta_id == IWL_INVALID_STATION) {
-                       IWL_DEBUG_RATE("LQ: ADD station %pm\n",
+                       IWL_DEBUG_RATE(priv, "LQ: ADD station %pm\n",
                                       hdr->addr1);
                        sta_id = iwl3945_add_station(priv,
-                                   hdr->addr1, 0, CMD_ASYNC);
+                                   hdr->addr1, 0, CMD_ASYNC, NULL);
                }
                if (sta_id != IWL_INVALID_STATION)
                        rs_sta->ibss_sta_added = 1;
@@ -695,21 +738,30 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
                rs_sta->start_rate = IWL_RATE_INVALID;
        }
 
+       /* force user max rate if set by user */
+       if ((max_rate_idx != -1) && (max_rate_idx < index)) {
+               if (rate_mask & (1 << max_rate_idx))
+                       index = max_rate_idx;
+       }
+
        window = &(rs_sta->win[index]);
 
        fail_count = window->counter - window->success_counter;
 
-       if (((fail_count <= IWL_RATE_MIN_FAILURE_TH) &&
+       if (((fail_count < IWL_RATE_MIN_FAILURE_TH) &&
             (window->success_counter < IWL_RATE_MIN_SUCCESS_TH))) {
                spin_unlock_irqrestore(&rs_sta->lock, flags);
 
-               IWL_DEBUG_RATE("Invalid average_tpt on rate %d: "
+               IWL_DEBUG_RATE(priv, "Invalid average_tpt on rate %d: "
                               "counter: %d, success_counter: %d, "
                               "expected_tpt is %sNULL\n",
                               index,
                               window->counter,
                               window->success_counter,
                               rs_sta->expected_tpt ? "not " : "");
+
+          /* Can't calculate this yet; not enough history */
+               window->average_tpt = IWL_INVALID_VALUE;
                goto out;
 
        }
@@ -721,6 +773,11 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
        low = high_low & 0xff;
        high = (high_low >> 8) & 0xff;
 
+       /* If user set max rate, dont allow higher than user constrain */
+       if ((max_rate_idx != -1) && (max_rate_idx < high))
+               high = IWL_RATE_INVALID;
+
+       /* Collect Measured throughputs of adjacent rates */
        if (low != IWL_RATE_INVALID)
                low_tpt = rs_sta->win[low].average_tpt;
 
@@ -729,56 +786,78 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
 
        spin_unlock_irqrestore(&rs_sta->lock, flags);
 
-       scale_action = 1;
+       scale_action = 0;
 
+       /* Low success ratio , need to drop the rate */
        if ((window->success_ratio < IWL_RATE_DECREASE_TH) || !current_tpt) {
-               IWL_DEBUG_RATE("decrease rate because of low success_ratio\n");
+               IWL_DEBUG_RATE(priv, "decrease rate because of low success_ratio\n");
                scale_action = -1;
-       } else if ((low_tpt == IWL_INV_TPT) && (high_tpt == IWL_INV_TPT))
-               scale_action = 1;
-       else if ((low_tpt != IWL_INV_TPT) && (high_tpt != IWL_INV_TPT) &&
+       /* 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 && window->success_ratio >= 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)) {
-               IWL_DEBUG_RATE("No action -- low [%d] & high [%d] < "
+
+               IWL_DEBUG_RATE(priv, "No action -- low [%d] & high [%d] < "
                               "current_tpt [%d]\n",
                               low_tpt, high_tpt, current_tpt);
                scale_action = 0;
+
+       /* At least one of the rates has better throughput */
        } else {
-               if (high_tpt != IWL_INV_TPT) {
-                       if (high_tpt > current_tpt)
+               if (high_tpt != IWL_INVALID_VALUE) {
+
+                       /* High rate has better throughput, Increase
+                        * rate */
+                       if (high_tpt > current_tpt &&
+                               window->success_ratio >= IWL_RATE_INCREASE_TH)
                                scale_action = 1;
                        else {
-                               IWL_DEBUG_RATE
-                                   ("decrease rate because of high tpt\n");
-                               scale_action = -1;
+                               IWL_DEBUG_RATE(priv,
+                                   "decrease rate because of high tpt\n");
+                               scale_action = 0;
                        }
-               } else if (low_tpt != IWL_INV_TPT) {
+               } else if (low_tpt != IWL_INVALID_VALUE) {
                        if (low_tpt > current_tpt) {
-                               IWL_DEBUG_RATE
-                                   ("decrease rate because of low tpt\n");
+                               IWL_DEBUG_RATE(priv,
+                                   "decrease rate because of low tpt\n");
                                scale_action = -1;
-                       } else
+                       } else if (window->success_ratio >= IWL_RATE_INCREASE_TH) {
+                               /* Lower rate has better
+                                * throughput,decrease rate */
                                scale_action = 1;
+                       }
                }
        }
 
-       if (scale_action == -1) {
-               if (window->success_ratio > IWL_SUCCESS_DOWN_TH)
-                       scale_action = 0;
-       } else if (scale_action == 1) {
-               if (window->success_ratio < IWL_SUCCESS_UP_TH) {
-                       IWL_DEBUG_RATE("No action -- success_ratio [%d] < "
-                              "SUCCESS UP\n", window->success_ratio);
-                       scale_action = 0;
-               }
-       }
+       /* 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) &&
+                   ((window->success_ratio > IWL_RATE_HIGH_TH) ||
+                    (current_tpt > (100 * rs_sta->expected_tpt[low]))))
+               scale_action = 0;
 
        switch (scale_action) {
        case -1:
+
+               /* Decrese rate */
                if (low != IWL_RATE_INVALID)
                        index = low;
                break;
 
        case 1:
+               /* Increase rate */
                if (high != IWL_RATE_INVALID)
                        index = high;
 
@@ -786,10 +865,11 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
 
        case 0:
        default:
+               /* No change */
                break;
        }
 
-       IWL_DEBUG_RATE("Selected %d (action %d) - low %d high %d\n",
+       IWL_DEBUG_RATE(priv, "Selected %d (action %d) - low %d high %d\n",
                       index, scale_action, low, high);
 
  out:
@@ -801,7 +881,7 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
        else
                info->control.rates[0].idx = rs_sta->last_txrate_idx;
 
-       IWL_DEBUG_RATE("leave: %d\n", index);
+       IWL_DEBUG_RATE(priv, "leave: %d\n", index);
 }
 
 #ifdef CONFIG_MAC80211_DEBUGFS
@@ -815,24 +895,31 @@ static ssize_t iwl3945_sta_dbgfs_stats_table_read(struct file *file,
                                                  char __user *user_buf,
                                                  size_t count, loff_t *ppos)
 {
-       char buff[1024];
+       char *buff;
        int desc = 0;
        int j;
+       ssize_t ret;
        struct iwl3945_rs_sta *lq_sta = file->private_data;
 
+       buff = kmalloc(1024, GFP_KERNEL);
+       if (!buff)
+               return -ENOMEM;
+
        desc += sprintf(buff + desc, "tx packets=%d last rate index=%d\n"
                        "rate=0x%X flush time %d\n",
                        lq_sta->tx_packets,
                        lq_sta->last_txrate_idx,
                        lq_sta->start_rate, jiffies_to_msecs(lq_sta->flush_time));
-       for (j = 0; j < IWL_RATE_COUNT; j++) {
+       for (j = 0; j < IWL_RATE_COUNT_3945; j++) {
                desc += sprintf(buff+desc,
                                "counter=%d success=%d %%=%d\n",
                                lq_sta->win[j].counter,
                                lq_sta->win[j].success_counter,
                                lq_sta->win[j].success_ratio);
        }
-       return simple_read_from_buffer(user_buf, count, ppos, buff, desc);
+       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 = {
@@ -877,18 +964,18 @@ static struct rate_control_ops rs_ops = {
 
 void iwl3945_rate_scale_init(struct ieee80211_hw *hw, s32 sta_id)
 {
-       struct iwl3945_priv *priv = hw->priv;
+       struct iwl_priv *priv = hw->priv;
        s32 rssi = 0;
        unsigned long flags;
        struct iwl3945_rs_sta *rs_sta;
        struct ieee80211_sta *sta;
        struct iwl3945_sta_priv *psta;
 
-       IWL_DEBUG_RATE("enter\n");
+       IWL_DEBUG_RATE(priv, "enter\n");
 
        rcu_read_lock();
 
-       sta = ieee80211_find_sta(hw, priv->stations[sta_id].sta.sta.addr);
+       sta = ieee80211_find_sta(hw, priv->stations_39[sta_id].sta.sta.addr);
        if (!sta) {
                rcu_read_unlock();
                return;
@@ -924,11 +1011,11 @@ void iwl3945_rate_scale_init(struct ieee80211_hw *hw, s32 sta_id)
        if (rssi == 0)
                rssi = IWL_MIN_RSSI_VAL;
 
-       IWL_DEBUG(IWL_DL_INFO | IWL_DL_RATE, "Network RSSI: %d\n", rssi);
+       IWL_DEBUG_RATE(priv, "Network RSSI: %d\n", rssi);
 
        rs_sta->start_rate = iwl3945_get_rate_index_by_rssi(rssi, priv->band);
 
-       IWL_DEBUG_RATE("leave: rssi %d assign rate index: "
+       IWL_DEBUG_RATE(priv, "leave: rssi %d assign rate index: "
                       "%d (plcp 0x%x)\n", rssi, rs_sta->start_rate,
                       iwl3945_rates[rs_sta->start_rate].plcp);
        rcu_read_unlock();