iwlwifi: report the rate index as an MCS rate number

If transmit in HT rate, report the rate index as an MCS rate number
instead of an index. so "iw" can display correct BitRate

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-rs.c b/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
index a1b0ff5..23a58b0 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
@@ -270,6 +270,8 @@
   {"60", "64QAM 5/6"}
 };
 
+#define MCS_INDEX_PER_STREAM	(8)
+
 static inline u8 rs_extract_rate(u32 rate_n_flags)
 {
 	return (u8)(rate_n_flags & 0xFF);
@@ -2518,12 +2520,33 @@
 		}
 	}
 
-	if (rate_idx < 0 || rate_idx > IWL_RATE_COUNT)
-		rate_idx = rate_lowest_index(sband, sta);
-	else if (sband->band == IEEE80211_BAND_5GHZ)
+	if (lq_sta->last_rate_n_flags & RATE_MCS_HT_MSK) {
 		rate_idx -= IWL_FIRST_OFDM_RATE;
-
+		/* 6M and 9M shared same MCS index */
+		rate_idx = (rate_idx > 0) ? (rate_idx - 1) : 0;
+		if (rs_extract_rate(lq_sta->last_rate_n_flags) >=
+		    IWL_RATE_MIMO3_6M_PLCP)
+			rate_idx = rate_idx + (2 * MCS_INDEX_PER_STREAM);
+		else if (rs_extract_rate(lq_sta->last_rate_n_flags) >=
+			 IWL_RATE_MIMO2_6M_PLCP)
+			rate_idx = rate_idx + MCS_INDEX_PER_STREAM;
+		info->control.rates[0].flags = IEEE80211_TX_RC_MCS;
+		if (lq_sta->last_rate_n_flags & RATE_MCS_SGI_MSK)
+			info->control.rates[0].flags |= IEEE80211_TX_RC_SHORT_GI;
+		if (lq_sta->last_rate_n_flags & RATE_MCS_DUP_MSK)
+			info->control.rates[0].flags |= IEEE80211_TX_RC_DUP_DATA;
+		if (lq_sta->last_rate_n_flags & RATE_MCS_FAT_MSK)
+			info->control.rates[0].flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
+		if (lq_sta->last_rate_n_flags & RATE_MCS_GF_MSK)
+			info->control.rates[0].flags |= IEEE80211_TX_RC_GREEN_FIELD;
+	} else {
+		if (rate_idx < 0 || rate_idx > IWL_RATE_COUNT)
+			rate_idx = rate_lowest_index(sband, sta);
+		else if (sband->band == IEEE80211_BAND_5GHZ)
+			rate_idx -= IWL_FIRST_OFDM_RATE;
+	}
 	info->control.rates[0].idx = rate_idx;
+
 }
 
 static void *rs_alloc_sta(void *priv_rate, struct ieee80211_sta *sta,