iwlwifi: mvm: BT Coex - avoid the shared antenna for management frames

If BT is active, we need to refrain from using the shared
antenna. This logic is done in the firmware when we use the
link quality tables. But for management frames, the rate is
written in the Tx command by the driver.
Hence the driver needs to make sure not use the shared
antenna when BT is active for any frames that don't use
the rate scale table such as management frames or multicast.

Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

drivers/net/wireless/iwlwifi/mvm/coex.c

@@ -1246,6 +1246,11 @@ bool iwl_mvm_bt_coex_is_mimo_allowed(struct iwl_mvm *mvm,
 	return lut_type != BT_COEX_LOOSE_LUT;
 }
 
+bool iwl_mvm_bt_coex_is_shared_ant_avail(struct iwl_mvm *mvm)
+{
+	return le32_to_cpu(mvm->last_bt_notif.bt_activity_grading) == BT_OFF;
+}
+
 bool iwl_mvm_bt_coex_is_tpc_allowed(struct iwl_mvm *mvm,
 				    enum ieee80211_band band)
 {

drivers/net/wireless/iwlwifi/mvm/mvm.h

@@ -973,6 +973,7 @@ u16 iwl_mvm_coex_agg_time_limit(struct iwl_mvm *mvm,
 				struct ieee80211_sta *sta);
 bool iwl_mvm_bt_coex_is_mimo_allowed(struct iwl_mvm *mvm,
 				     struct ieee80211_sta *sta);
+bool iwl_mvm_bt_coex_is_shared_ant_avail(struct iwl_mvm *mvm);
 bool iwl_mvm_bt_coex_is_tpc_allowed(struct iwl_mvm *mvm,
 				    enum ieee80211_band band);
 u8 iwl_mvm_bt_coex_tx_prio(struct iwl_mvm *mvm, struct ieee80211_hdr *hdr,

drivers/net/wireless/iwlwifi/mvm/tx.c

@@ -205,7 +205,13 @@ static void iwl_mvm_set_tx_cmd_rate(struct iwl_mvm *mvm,
 	mvm->mgmt_last_antenna_idx =
 		iwl_mvm_next_antenna(mvm, mvm->fw->valid_tx_ant,
 				     mvm->mgmt_last_antenna_idx);
-	rate_flags = BIT(mvm->mgmt_last_antenna_idx) << RATE_MCS_ANT_POS;
+
+	if (info->band == IEEE80211_BAND_2GHZ &&
+	    !iwl_mvm_bt_coex_is_shared_ant_avail(mvm))
+		rate_flags = BIT(ANT_A) << RATE_MCS_ANT_POS;
+	else
+		rate_flags =
+			BIT(mvm->mgmt_last_antenna_idx) << RATE_MCS_ANT_POS;
 
 	/* Set CCK flag as needed */
 	if ((rate_idx >= IWL_FIRST_CCK_RATE) && (rate_idx <= IWL_LAST_CCK_RATE))