iwl3945: Fix rate scale for B-mode connection

This patch make sure we use only CCK rate for B only network.
For 3945 driver, it sets REPLY_RATE_SCALE command every time
we connect to a new network. In this command we set for every
rate the number of try and next rate. The problem mac80211 reports
same mode for both B and G mode as IEEE80211_BAND_2GHZ which will cause
using invalid rate other than CCK in B only network. THis patch
on association will examine sta valid rate on association, if no
OFDM rate in valid available rates it considers it as B only mode so
we can set REPLY_RATE_SCALE command with valid B only network and only
choose CCK rate in rate scaling.

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>

3 files changed, 39 insertions, 16 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-3945-rs.c b/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
index b03dd06ceabf..047317f26483 100644
--- a/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
@@ -335,10 +335,11 @@ static void iwl3945_collect_tx_data(struct iwl3945_rs_sta *rs_sta,
 
 }
 
-static void rs_rate_init(void *priv, struct ieee80211_supported_band *sband,
+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;
         int i;
 
         IWL_DEBUG_RATE("enter\n");
@@ -348,16 +349,21 @@ static void rs_rate_init(void *priv, struct ieee80211_supported_band *sband,
          * previous packets? Need to have IEEE 802.1X auth succeed immediately
          * after assoc.. */
 
-        for (i = IWL_RATE_COUNT - 1; i >= 0; i--) {
+        for (i = sband->n_bitrates - 1; i >= 0; i--) {
                 if (sta->supp_rates[sband->band] & (1 << i)) {
                         rs_sta->last_txrate_idx = i;
                         break;
                 }
         }
 
+        priv->sta_supp_rates = sta->supp_rates[sband->band];
         /* For 5 GHz band it start at IWL_FIRST_OFDM_RATE */
-        if (sband->band == IEEE80211_BAND_5GHZ)
+        if (sband->band == IEEE80211_BAND_5GHZ) {
                 rs_sta->last_txrate_idx += IWL_FIRST_OFDM_RATE;
+                priv->sta_supp_rates = priv->sta_supp_rates <<
+                                                IWL_FIRST_OFDM_RATE;
+        }
+
 
         IWL_DEBUG_RATE("leave\n");
 }
diff --git a/drivers/net/wireless/iwlwifi/iwl-3945.c b/drivers/net/wireless/iwlwifi/iwl-3945.c
index 4e6b7154c223..4e9e592b1cab 100644
--- a/drivers/net/wireless/iwlwifi/iwl-3945.c
+++ b/drivers/net/wireless/iwlwifi/iwl-3945.c
@@ -277,12 +277,14 @@ int iwl3945_rs_next_rate(struct iwl3945_priv *priv, int rate)
                 else if (rate == IWL_RATE_6M_INDEX)
                         next_rate = IWL_RATE_6M_INDEX;
                 break;
-/* XXX cannot be invoked in current mac80211 so not a regression
-        case MODE_IEEE80211B:
-                if (rate == IWL_RATE_11M_INDEX_TABLE)
-                        next_rate = IWL_RATE_5M_INDEX_TABLE;
+        case IEEE80211_BAND_2GHZ:
+                if (!(priv->sta_supp_rates & IWL_OFDM_RATES_MASK) &&
+                    iwl3945_is_associated(priv)) {
+                        if (rate == IWL_RATE_11M_INDEX)
+                                next_rate = IWL_RATE_5M_INDEX;
+                }
                 break;
- */
+
         default:
                 break;
         }
@@ -2378,7 +2380,8 @@ int iwl3945_init_hw_rate_table(struct iwl3945_priv *priv)
                         iwl3945_hw_set_rate_n_flags(iwl3945_rates[i].plcp, 0);
                 table[index].try_cnt = priv->retry_rate;
                 prev_index = iwl3945_get_prev_ieee_rate(i);
-                table[index].next_rate_index = iwl3945_rates[prev_index].table_rs_index;
+                table[index].next_rate_index =
+                                iwl3945_rates[prev_index].table_rs_index;
         }
 
         switch (priv->band) {
@@ -2386,11 +2389,14 @@ int iwl3945_init_hw_rate_table(struct iwl3945_priv *priv)
                 IWL_DEBUG_RATE("Select A mode rate scale\n");
                 /* If one of the following CCK rates is used,
                  * have it fall back to the 6M OFDM rate */
-                for (i = IWL_RATE_1M_INDEX_TABLE; i <= IWL_RATE_11M_INDEX_TABLE; i++)
-                        table[i].next_rate_index = iwl3945_rates[IWL_FIRST_OFDM_RATE].table_rs_index;
+                for (i = IWL_RATE_1M_INDEX_TABLE;
+                        i <= IWL_RATE_11M_INDEX_TABLE; i++)
+                        table[i].next_rate_index =
+                          iwl3945_rates[IWL_FIRST_OFDM_RATE].table_rs_index;
 
                 /* Don't fall back to CCK rates */
-                table[IWL_RATE_12M_INDEX_TABLE].next_rate_index = IWL_RATE_9M_INDEX_TABLE;
+                table[IWL_RATE_12M_INDEX_TABLE].next_rate_index =
+                                                IWL_RATE_9M_INDEX_TABLE;
 
                 /* Don't drop out of OFDM rates */
                 table[IWL_RATE_6M_INDEX_TABLE].next_rate_index =
@@ -2401,11 +2407,20 @@ int iwl3945_init_hw_rate_table(struct iwl3945_priv *priv)
                 IWL_DEBUG_RATE("Select B/G mode rate scale\n");
                 /* If an OFDM rate is used, have it fall back to the
                  * 1M CCK rates */
-                for (i = IWL_RATE_6M_INDEX_TABLE; i <= IWL_RATE_54M_INDEX_TABLE; i++)
-                        table[i].next_rate_index = iwl3945_rates[IWL_FIRST_CCK_RATE].table_rs_index;
 
-                /* CCK shouldn't fall back to OFDM... */
-                table[IWL_RATE_11M_INDEX_TABLE].next_rate_index = IWL_RATE_5M_INDEX_TABLE;
+                if (!(priv->sta_supp_rates & IWL_OFDM_RATES_MASK) &&
+                    iwl3945_is_associated(priv)) {
+
+                        index = IWL_FIRST_CCK_RATE;
+                        for (i = IWL_RATE_6M_INDEX_TABLE;
+                             i <= IWL_RATE_54M_INDEX_TABLE; i++)
+                                table[i].next_rate_index =
+                                        iwl3945_rates[index].table_rs_index;
+
+                        index = IWL_RATE_11M_INDEX_TABLE;
+                        /* CCK shouldn't fall back to OFDM... */
+                        table[index].next_rate_index = IWL_RATE_5M_INDEX_TABLE;
+                }
                 break;
 
         default:
diff --git a/drivers/net/wireless/iwlwifi/iwl-3945.h b/drivers/net/wireless/iwlwifi/iwl-3945.h
index 5c2c15e65a63..d7d13a9e22bd 100644
--- a/drivers/net/wireless/iwlwifi/iwl-3945.h
+++ b/drivers/net/wireless/iwlwifi/iwl-3945.h
@@ -810,6 +810,8 @@ struct iwl3945_priv {
         u16 active_rate;
         u16 active_rate_basic;
 
+        u32 sta_supp_rates;
+
         u8 call_post_assoc_from_beacon;
         /* Rate scaling data */
         s8 data_retry_limit;