iwl3945: Fix iwl3945 rate scaling.

3945 rate scaling was broken in recent tree. This patch fix the following:
	1- Get TX response info and update rates window.
	2- Rate scaling selection.
	3- Flush window timer.

Signed-off-by: Mohamed Abbas <mohamed.abbas@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 52 insertions, 55 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-3945-rs.c b/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
index 76100d5786fb..b03dd06ceabf 100644
--- a/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
@@ -117,9 +117,11 @@ static struct iwl3945_tpt_entry iwl3945_tpt_table_g[] = {
 };
 
 #define IWL_RATE_MAX_WINDOW          62
-#define IWL_RATE_FLUSH        (3*HZ/10)
+#define IWL_RATE_FLUSH           (3*HZ)
 #define IWL_RATE_WIN_FLUSH       (HZ/2)
 #define IWL_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_SUCCESS_TH       8
 #define IWL_RATE_DECREASE_TH       1920
@@ -206,6 +208,7 @@ static int iwl3945_rate_scale_flush_windows(struct iwl3945_rs_sta *rs_sta)
 
 #define IWL_RATE_FLUSH_MAX              5000    /* msec */
 #define IWL_RATE_FLUSH_MIN              50      /* msec */
+#define IWL_AVERAGE_PACKETS             1500
 
 static void iwl3945_bg_rate_scale_flush(unsigned long data)
 {
@@ -220,8 +223,6 @@ static void iwl3945_bg_rate_scale_flush(unsigned long data)
 
         spin_lock_irqsave(&rs_sta->lock, flags);
 
-        rs_sta->flush_pending = 0;
-
         /* Number of packets Rx'd since last time this timer ran */
         packet_count = (rs_sta->tx_packets - rs_sta->last_tx_packets) + 1;
 
@@ -230,7 +231,6 @@ static void iwl3945_bg_rate_scale_flush(unsigned long data)
         if (unflushed) {
                 duration =
                     jiffies_to_msecs(jiffies - rs_sta->last_partial_flush);
-/*              duration = jiffies_to_msecs(rs_sta->flush_time); */
 
                 IWL_DEBUG_RATE("Tx'd %d packets in %dms\n",
                                packet_count, duration);
@@ -242,9 +242,11 @@ static void iwl3945_bg_rate_scale_flush(unsigned long data)
                         pps = 0;
 
                 if (pps) {
-                        duration = IWL_RATE_FLUSH_MAX / pps;
+                        duration = (IWL_AVERAGE_PACKETS * 1000) / pps;
                         if (duration < IWL_RATE_FLUSH_MIN)
                                 duration = IWL_RATE_FLUSH_MIN;
+                        else if (duration > IWL_RATE_FLUSH_MAX)
+                                duration = IWL_RATE_FLUSH_MAX;
                 } else
                         duration = IWL_RATE_FLUSH_MAX;
 
@@ -257,8 +259,10 @@ static void iwl3945_bg_rate_scale_flush(unsigned long data)
                           rs_sta->flush_time);
 
                 rs_sta->last_partial_flush = jiffies;
+        } else {
+                rs_sta->flush_time = IWL_RATE_FLUSH;
+                rs_sta->flush_pending = 0;
         }
-
         /* If there weren't any unflushed entries, we don't schedule the timer
          * to run again */
 
@@ -278,17 +282,18 @@ static void iwl3945_bg_rate_scale_flush(unsigned long data)
  */
 static void iwl3945_collect_tx_data(struct iwl3945_rs_sta *rs_sta,
                                 struct iwl3945_rate_scale_data *window,
-                                int success, int retries)
+                                int success, int retries, int index)
 {
         unsigned long flags;
+        s32 fail_count;
 
         if (!retries) {
                 IWL_DEBUG_RATE("leave: retries == 0 -- should be at least 1\n");
                 return;
         }
 
+        spin_lock_irqsave(&rs_sta->lock, flags);
         while (retries--) {
-                spin_lock_irqsave(&rs_sta->lock, flags);
 
                 /* If we have filled up the window then subtract one from the
                  * success counter if the high-bit is counting toward
@@ -316,8 +321,18 @@ static void iwl3945_collect_tx_data(struct iwl3945_rs_sta *rs_sta,
                 /* Tag this window as having been updated */
                 window->stamp = jiffies;
 
-                spin_unlock_irqrestore(&rs_sta->lock, flags);
         }
+
+        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 = ((window->success_ratio *
+                                rs_sta->expected_tpt[index] + 64) / 128);
+        else
+                window->average_tpt = IWL_INV_TPT;
+
+        spin_unlock_irqrestore(&rs_sta->lock, flags);
+
 }
 
 static void rs_rate_init(void *priv, struct ieee80211_supported_band *sband,
@@ -429,19 +444,16 @@ static void rs_tx_status(void *priv_rate, struct ieee80211_supported_band *sband
                          struct ieee80211_sta *sta, void *priv_sta,
                          struct sk_buff *skb)
 {
-        u8 retries = 0, current_count;
+        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 iwl3945_rs_sta *rs_sta = priv_sta;
         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
-        int i;
 
         IWL_DEBUG_RATE("enter\n");
 
-        for (i = 0; i < IEEE80211_TX_MAX_RATES; i++)
-                retries += info->status.rates[i].count;
-        retries--;
+        retries = info->status.rates[0].count;
 
         first_index = sband->bitrates[info->status.rates[0].idx].hw_value;
         if ((first_index < 0) || (first_index >= IWL_RATE_COUNT)) {
@@ -469,9 +481,9 @@ static void rs_tx_status(void *priv_rate, struct ieee80211_supported_band *sband
          * at which the frame was finally transmitted (or failed if no
          * ACK)
          */
-        while (retries > 0) {
-                if (retries < priv->retry_rate) {
-                        current_count = retries;
+        while (retries > 1) {
+                if ((retries - 1) < priv->retry_rate) {
+                        current_count = (retries - 1);
                         last_index = scale_rate_index;
                 } else {
                         current_count = priv->retry_rate;
@@ -483,15 +495,13 @@ static void rs_tx_status(void *priv_rate, struct ieee80211_supported_band *sband
                  * as was used for it (per current_count) */
                 iwl3945_collect_tx_data(rs_sta,
                                     &rs_sta->win[scale_rate_index],
-                                    0, current_count);
+                                    0, current_count, scale_rate_index);
                 IWL_DEBUG_RATE("Update rate %d for %d retries.\n",
                                scale_rate_index, current_count);
 
                 retries -= current_count;
 
-                if (retries)
-                        scale_rate_index =
-                            iwl3945_rs_next_rate(priv, scale_rate_index);
+                scale_rate_index = last_index;
         }
 
 
@@ -502,7 +512,7 @@ static void rs_tx_status(void *priv_rate, struct ieee80211_supported_band *sband
                        "success" : "failure");
         iwl3945_collect_tx_data(rs_sta,
                             &rs_sta->win[last_index],
-                            info->flags & IEEE80211_TX_STAT_ACK, 1);
+                            info->flags & IEEE80211_TX_STAT_ACK, 1, last_index);
 
         /* We updated the rate scale window -- if its been more than
          * flush_time since the last run, schedule the flush
@@ -510,9 +520,10 @@ static void rs_tx_status(void *priv_rate, struct ieee80211_supported_band *sband
         spin_lock_irqsave(&rs_sta->lock, flags);
 
         if (!rs_sta->flush_pending &&
-            time_after(jiffies, rs_sta->last_partial_flush +
+            time_after(jiffies, rs_sta->last_flush +
                        rs_sta->flush_time)) {
 
+                rs_sta->last_partial_flush = jiffies;
                 rs_sta->flush_pending = 1;
                 mod_timer(&rs_sta->rate_scale_flush,
                           jiffies + rs_sta->flush_time);
@@ -660,8 +671,13 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
 
         spin_lock_irqsave(&rs_sta->lock, flags);
 
+        /* for recent assoc, choose best rate regarding
+         * to rssi value
+         */
         if (rs_sta->start_rate != IWL_RATE_INVALID) {
-                index = rs_sta->start_rate;
+                if (rs_sta->start_rate < index &&
+                   (rate_mask & (1 << rs_sta->start_rate)))
+                        index = rs_sta->start_rate;
                 rs_sta->start_rate = IWL_RATE_INVALID;
         }
 
@@ -671,7 +687,6 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
 
         if (((fail_count <= IWL_RATE_MIN_FAILURE_TH) &&
              (window->success_counter < IWL_RATE_MIN_SUCCESS_TH))) {
-                window->average_tpt = IWL_INV_TPT;
                 spin_unlock_irqrestore(&rs_sta->lock, flags);
 
                 IWL_DEBUG_RATE("Invalid average_tpt on rate %d: "
@@ -685,8 +700,6 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
 
         }
 
-        window->average_tpt = ((window->success_ratio *
-                                rs_sta->expected_tpt[index] + 64) / 128);
         current_tpt = window->average_tpt;
 
         high_low = iwl3945_get_adjacent_rate(rs_sta, index, rate_mask,
@@ -734,13 +747,15 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
                 }
         }
 
-        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;
+        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;
+                }
         }
 
         switch (scale_action) {
diff --git a/drivers/net/wireless/iwlwifi/iwl-3945.c b/drivers/net/wireless/iwlwifi/iwl-3945.c
index 61500044f5da..d95a15fc2602 100644
--- a/drivers/net/wireless/iwlwifi/iwl-3945.c
+++ b/drivers/net/wireless/iwlwifi/iwl-3945.c
@@ -337,7 +337,7 @@ static void iwl3945_rx_reply_tx(struct iwl3945_priv *priv,
         struct iwl3945_tx_resp *tx_resp = (void *)&pkt->u.raw[0];
         u32  status = le32_to_cpu(tx_resp->status);
         int rate_idx;
-        int fail, i;
+        int fail;
 
         if ((index >= txq->q.n_bd) || (iwl3945_x2_queue_used(&txq->q, index) == 0)) {
                 IWL_ERROR("Read index for DMA queue txq_id (%d) index %d "
@@ -356,27 +356,9 @@ static void iwl3945_rx_reply_tx(struct iwl3945_priv *priv,
                 rate_idx -= IWL_FIRST_OFDM_RATE;
 
         fail = tx_resp->failure_frame;
-        for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
-                int next = iwl3945_rs_next_rate(priv, rate_idx);
 
-                info->status.rates[i].idx = rate_idx;
-
-                /*
-                 * Put remaining into the last count as best approximation
-                 * of saying exactly what the hardware would have done...
-                 */
-                if ((rate_idx == next) || (i == IEEE80211_TX_MAX_RATES - 1)) {
-                        info->status.rates[i].count = fail;
-                        break;
-                }
-
-                info->status.rates[i].count = priv->retry_rate;
-                fail -= priv->retry_rate;
-                rate_idx = next;
-                if (fail <= 0)
-                        break;
-        }
-        info->status.rates[i].count++; /* add final attempt */
+        info->status.rates[0].idx = rate_idx;
+        info->status.rates[0].count = fail + 1; /* add final attempt */
 
         /* tx_status->rts_retry_count = tx_resp->failure_rts; */
         info->flags |= ((status & TX_STATUS_MSK) == TX_STATUS_SUCCESS) ?