iwlwifi: use iwl_hwrate_get_mac80211_idx where appropriate

For HT packets, mac80211 expects the rate_idx to be an MCS number, which is the
lower byte of rate_n_flags.  However, iwl_hwrate_to_plcp_idx takes the MCS
number and reduces it down to the range 0-8 (6 to 60 Mbps), removing the bits
that signify multiply streams, HT40 Duplicate mode, or unequal modulation.
This version is used for various internal purposes through the driver.

Add the function iwl_hwrate_get_mac80211_idx, an alternate version which takes
the rate and the band and returns the mac80211 index (MCS, for HT packets, and
PLCP rate, for legacy packets).

Signed-off-by: Daniel C Halperin <daniel.c.halperin@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 35 insertions, 12 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-rs.c b/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
index 8239e5508cac..40b207aa8fef 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
@@ -878,6 +878,12 @@ static void rs_tx_status(void *priv_r, struct ieee80211_supported_band *sband,
                 rs_index -= IWL_FIRST_OFDM_RATE;
         mac_flags = info->status.rates[0].flags;
         mac_index = info->status.rates[0].idx;
+        /* For HT packets, map MCS to PLCP */
+        if (mac_flags & IEEE80211_TX_RC_MCS) {
+                mac_index &= RATE_MCS_CODE_MSK; /* Remove # of streams */
+                if (mac_index >= (IWL_RATE_9M_INDEX - IWL_FIRST_OFDM_RATE))
+                        mac_index++;
+        }
 
         if ((mac_index < 0) ||
             (tbl_type.is_SGI != !!(mac_flags & IEEE80211_TX_RC_SHORT_GI)) ||
@@ -886,8 +892,8 @@ static void rs_tx_status(void *priv_r, struct ieee80211_supported_band *sband,
             (tbl_type.ant_type != info->antenna_sel_tx) ||
             (!!(tx_rate & RATE_MCS_HT_MSK) != !!(mac_flags & IEEE80211_TX_RC_MCS)) ||
             (!!(tx_rate & RATE_MCS_GF_MSK) != !!(mac_flags & IEEE80211_TX_RC_GREEN_FIELD)) ||
-            rs_index != mac_index) {
-                IWL_DEBUG_RATE(priv, "initial rate does not match 0x%x\n", tx_rate);
+            (rs_index != mac_index)) {
+                IWL_DEBUG_RATE(priv, "initial rate %d does not match %d (0x%x)\n", mac_index, rs_index, tx_rate);
                 /* the last LQ command could failed so the LQ in ucode not
                  * the same in driver sync up
                  */
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.c b/drivers/net/wireless/iwlwifi/iwl-core.c
index 813582467ffb..acfd7b40afb8 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.c
+++ b/drivers/net/wireless/iwlwifi/iwl-core.c
@@ -96,7 +96,6 @@ EXPORT_SYMBOL(iwl_rates);
 void iwl_hwrate_to_tx_control(struct iwl_priv *priv, u32 rate_n_flags,
                                   struct ieee80211_tx_info *info)
 {
-        int rate_index;
         struct ieee80211_tx_rate *r = &info->control.rates[0];
 
         info->antenna_sel_tx =
@@ -111,10 +110,7 @@ void iwl_hwrate_to_tx_control(struct iwl_priv *priv, u32 rate_n_flags,
                 r->flags |= IEEE80211_TX_RC_DUP_DATA;
         if (rate_n_flags & RATE_MCS_SGI_MSK)
                 r->flags |= IEEE80211_TX_RC_SHORT_GI;
-        rate_index = iwl_hwrate_to_plcp_idx(rate_n_flags);
-        if (info->band == IEEE80211_BAND_5GHZ)
-                rate_index -= IWL_FIRST_OFDM_RATE;
-        r->idx = rate_index;
+        r->idx = iwl_hwrate_to_mac80211_idx(rate_n_flags, info->band);
 }
 EXPORT_SYMBOL(iwl_hwrate_to_tx_control);
 
@@ -149,6 +145,27 @@ int iwl_hwrate_to_plcp_idx(u32 rate_n_flags)
 }
 EXPORT_SYMBOL(iwl_hwrate_to_plcp_idx);
 
+int iwl_hwrate_to_mac80211_idx(u32 rate_n_flags, enum ieee80211_band band)
+{
+        int idx = 0;
+        int band_offset = 0;
+
+        /* HT rate format: mac80211 wants an MCS number, which is just LSB */
+        if (rate_n_flags & RATE_MCS_HT_MSK) {
+                idx = (rate_n_flags & 0xff);
+                return idx;
+        /* Legacy rate format, search for match in table */
+        } else {
+                if (band == IEEE80211_BAND_5GHZ)
+                        band_offset = IWL_FIRST_OFDM_RATE;
+                for (idx = band_offset; idx < IWL_RATE_COUNT_LEGACY; idx++)
+                        if (iwl_rates[idx].plcp == (rate_n_flags & 0xFF))
+                                return idx - band_offset;
+        }
+
+        return -1;
+}
+
 u8 iwl_toggle_tx_ant(struct iwl_priv *priv, u8 ant)
 {
         int i;
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.h b/drivers/net/wireless/iwlwifi/iwl-core.h
index 62d90364b61d..c04d2a270819 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.h
+++ b/drivers/net/wireless/iwlwifi/iwl-core.h
@@ -423,6 +423,7 @@ int iwl_set_tx_power(struct iwl_priv *priv, s8 tx_power, bool force);
 void iwl_hwrate_to_tx_control(struct iwl_priv *priv, u32 rate_n_flags,
                               struct ieee80211_tx_info *info);
 int iwl_hwrate_to_plcp_idx(u32 rate_n_flags);
+int iwl_hwrate_to_mac80211_idx(u32 rate_n_flags, enum ieee80211_band band);
 
 u8 iwl_rate_get_lowest_plcp(struct iwl_priv *priv);
 
diff --git a/drivers/net/wireless/iwlwifi/iwl-rx.c b/drivers/net/wireless/iwlwifi/iwl-rx.c
index e34d3fcb6c3d..8150c5c3a16b 100644
--- a/drivers/net/wireless/iwlwifi/iwl-rx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-rx.c
@@ -962,6 +962,9 @@ void iwl_rx_reply_rx(struct iwl_priv *priv,
                 return;
         }
 
+        /* This will be used in several places later */
+        rate_n_flags = le32_to_cpu(phy_res->rate_n_flags);
+
         /* rx_status carries information about the packet to mac80211 */
         rx_status.mactime = le64_to_cpu(phy_res->timestamp);
         rx_status.freq =
@@ -969,10 +972,7 @@ void iwl_rx_reply_rx(struct iwl_priv *priv,
         rx_status.band = (phy_res->phy_flags & RX_RES_PHY_FLAGS_BAND_24_MSK) ?
                                 IEEE80211_BAND_2GHZ : IEEE80211_BAND_5GHZ;
         rx_status.rate_idx =
-                iwl_hwrate_to_plcp_idx(le32_to_cpu(phy_res->rate_n_flags));
-        if (rx_status.band == IEEE80211_BAND_5GHZ)
-                rx_status.rate_idx -= IWL_FIRST_OFDM_RATE;
-
+                iwl_hwrate_to_mac80211_idx(rate_n_flags, rx_status.band);
         rx_status.flag = 0;
 
         /* TSF isn't reliable. In order to allow smooth user experience,
@@ -1034,7 +1034,6 @@ void iwl_rx_reply_rx(struct iwl_priv *priv,
                 rx_status.flag |= RX_FLAG_SHORTPRE;
 
         /* Set up the HT phy flags */
-        rate_n_flags = le32_to_cpu(phy_res->rate_n_flags);
         if (rate_n_flags & RATE_MCS_HT_MSK)
                 rx_status.flag |= RX_FLAG_HT;
         if (rate_n_flags & RATE_MCS_HT40_MSK)