rtw88: coex: Set 4 slot mode for A2DP

With shallow buffer size, certain BT devices have active
A2DP flow control to fill buffer frequently. If the slot
is not at BT side, data can't be sent successfully to BT
devices, and will cause audio glitch.

To resolve this issue, this commit splits TUs into 4-slots
instead of 2-slot for all of the A2DP related coexistence
strategies. That makes BT have higher opportunity to fill
the A2DP buffer in time, and the audio quality could be
more stable and smooth.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/realtek/rtw88/coex.c

@@ -1302,6 +1302,7 @@ static void rtw_coex_action_bt_inquiry(struct rtw_dev *rtwdev)
 	struct rtw_chip_info *chip = rtwdev->chip;
 	bool wl_hi_pri = false;
 	u8 table_case, tdma_case;
+	u32 slot_type = 0;
 
 	if (coex_stat->wl_linkscan_proc || coex_stat->wl_hi_pri_task1 ||
 	    coex_stat->wl_hi_pri_task2)
@@ -1312,14 +1313,16 @@ static void rtw_coex_action_bt_inquiry(struct rtw_dev *rtwdev)
 		if (wl_hi_pri) {
 			table_case = 15;
 			if (coex_stat->bt_a2dp_exist &&
-			    !coex_stat->bt_pan_exist)
+			    !coex_stat->bt_pan_exist) {
+				slot_type = TDMA_4SLOT;
 				tdma_case = 11;
-			else if (coex_stat->wl_hi_pri_task1)
+			} else if (coex_stat->wl_hi_pri_task1) {
 				tdma_case = 6;
-			else if (!coex_stat->bt_page)
+			} else if (!coex_stat->bt_page) {
 				tdma_case = 8;
-			else
+			} else {
 				tdma_case = 9;
+			}
 		} else if (coex_stat->wl_connected) {
 			table_case = 10;
 			tdma_case = 10;
@@ -1355,7 +1358,7 @@ static void rtw_coex_action_bt_inquiry(struct rtw_dev *rtwdev)
 	rtw_coex_set_ant_path(rtwdev, false, COEX_SET_ANT_2G);
 	rtw_coex_set_rf_para(rtwdev, chip->wl_rf_para_rx[0]);
 	rtw_coex_table(rtwdev, table_case);
-	rtw_coex_tdma(rtwdev, false, tdma_case);
+	rtw_coex_tdma(rtwdev, false, tdma_case | slot_type);
 }
 
 static void rtw_coex_action_bt_hfp(struct rtw_dev *rtwdev)
@@ -1469,13 +1472,13 @@ static void rtw_coex_action_bt_a2dp(struct rtw_dev *rtwdev)
 
 	if (efuse->share_ant) {
 		/* Shared-Ant */
+		slot_type = TDMA_4SLOT;
+
 		if (coex_stat->wl_gl_busy && coex_stat->wl_noisy_level == 0)
 			table_case = 10;
 		else
 			table_case = 9;
 
-		slot_type = TDMA_4SLOT;
-
 		if (coex_stat->wl_gl_busy)
 			tdma_case = 13;
 		else
@@ -1579,13 +1582,14 @@ static void rtw_coex_action_bt_a2dp_hid(struct rtw_dev *rtwdev)
 
 	if (efuse->share_ant) {
 		/* Shared-Ant */
+		slot_type = TDMA_4SLOT;
+
 		if (coex_stat->bt_ble_exist)
 			table_case = 26;
 		else
 			table_case = 9;
 
 		if (coex_stat->wl_gl_busy) {
-			slot_type = TDMA_4SLOT;
 			tdma_case = 13;
 		} else {
 			tdma_case = 14;
@@ -1788,10 +1792,12 @@ static void rtw_coex_action_wl_linkscan(struct rtw_dev *rtwdev)
 	struct rtw_efuse *efuse = &rtwdev->efuse;
 	struct rtw_chip_info *chip = rtwdev->chip;
 	u8 table_case, tdma_case;
+	u32 slot_type = 0;
 
 	if (efuse->share_ant) {
 		/* Shared-Ant */
 		if (coex_stat->bt_a2dp_exist) {
+			slot_type = TDMA_4SLOT;
 			table_case = 9;
 			tdma_case = 11;
 		} else {
@@ -1812,7 +1818,7 @@ static void rtw_coex_action_wl_linkscan(struct rtw_dev *rtwdev)
 	rtw_coex_set_ant_path(rtwdev, true, COEX_SET_ANT_2G);
 	rtw_coex_set_rf_para(rtwdev, chip->wl_rf_para_rx[0]);
 	rtw_coex_table(rtwdev, table_case);
-	rtw_coex_tdma(rtwdev, false, tdma_case);
+	rtw_coex_tdma(rtwdev, false, tdma_case | slot_type);
 }
 
 static void rtw_coex_action_wl_not_connected(struct rtw_dev *rtwdev)