[PATCH 2/2] Bluetooth: btusb: mediatek: return error code for failed register access

[sean . wang]

From: Sean Wang <sean.wang@xxxxxxxxxxxx>

Update the code to immediately return an error code if accessing a
related register fails. This ensures that our desired logic for
subsequent register operations is maintained and allows us to promptly
catch any unexpected errors.

Signed-off-by: Sean Wang <sean.wang@xxxxxxxxxxxx>
---
 drivers/bluetooth/btusb.c | 116 ++++++++++++++++++++++++++++----------
 1 file changed, 85 insertions(+), 31 deletions(-)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index fcdd660add19..e862e4648082 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -3037,47 +3037,96 @@ static int btusb_mtk_subsys_reset(struct hci_dev *hdev, u32 dev_id)
 	int err;
 
 	if (dev_id == 0x7922) {
-		btusb_mtk_uhw_reg_read(data, MTK_BT_SUBSYS_RST, &val);
+		err = btusb_mtk_uhw_reg_read(data, MTK_BT_SUBSYS_RST, &val);
+		if (err < 0)
+			return err;
 		val |= 0x00002020;
-		btusb_mtk_uhw_reg_write(data, MTK_BT_SUBSYS_RST, val);
-		btusb_mtk_uhw_reg_write(data, MTK_EP_RST_OPT, 0x00010001);
-		btusb_mtk_uhw_reg_read(data, MTK_BT_SUBSYS_RST, &val);
+		err = btusb_mtk_uhw_reg_write(data, MTK_BT_SUBSYS_RST, val);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_write(data, MTK_EP_RST_OPT, 0x00010001);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_read(data, MTK_BT_SUBSYS_RST, &val);
+		if (err < 0)
+			return err;
 		val |= BIT(0);
-		btusb_mtk_uhw_reg_write(data, MTK_BT_SUBSYS_RST, val);
+		err = btusb_mtk_uhw_reg_write(data, MTK_BT_SUBSYS_RST, val);
+		if (err < 0)
+			return err;
 		msleep(100);
 	} else if (dev_id == 0x7925) {
-		btusb_mtk_uhw_reg_read(data, MTK_BT_RESET_REG_CONNV3, &val);
+		err = btusb_mtk_uhw_reg_read(data, MTK_BT_RESET_REG_CONNV3, &val);
+		if (err < 0)
+			return err;
 		val |= (1 << 5);
-		btusb_mtk_uhw_reg_write(data, MTK_BT_RESET_REG_CONNV3, val);
-		btusb_mtk_uhw_reg_read(data, MTK_BT_RESET_REG_CONNV3, &val);
+		err = btusb_mtk_uhw_reg_write(data, MTK_BT_RESET_REG_CONNV3, val);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_read(data, MTK_BT_RESET_REG_CONNV3, &val);
+		if (err < 0)
+			return err;
 		val &= 0xFFFF00FF;
 		val |= (1 << 13);
-		btusb_mtk_uhw_reg_write(data, MTK_BT_RESET_REG_CONNV3, val);
-		btusb_mtk_uhw_reg_write(data, MTK_EP_RST_OPT, 0x00010001);
-		btusb_mtk_uhw_reg_read(data, MTK_BT_RESET_REG_CONNV3, &val);
+		err = btusb_mtk_uhw_reg_write(data, MTK_BT_RESET_REG_CONNV3, val);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_write(data, MTK_EP_RST_OPT, 0x00010001);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_read(data, MTK_BT_RESET_REG_CONNV3, &val);
+		if (err < 0)
+			return err;
 		val |= (1 << 0);
-		btusb_mtk_uhw_reg_write(data, MTK_BT_RESET_REG_CONNV3, val);
-		btusb_mtk_uhw_reg_write(data, MTK_UDMA_INT_STA_BT, 0x000000FF);
-		btusb_mtk_uhw_reg_read(data, MTK_UDMA_INT_STA_BT, &val);
-		btusb_mtk_uhw_reg_write(data, MTK_UDMA_INT_STA_BT1, 0x000000FF);
-		btusb_mtk_uhw_reg_read(data, MTK_UDMA_INT_STA_BT1, &val);
+		err = btusb_mtk_uhw_reg_write(data, MTK_BT_RESET_REG_CONNV3, val);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_write(data, MTK_UDMA_INT_STA_BT, 0x000000FF);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_read(data, MTK_UDMA_INT_STA_BT, &val);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_write(data, MTK_UDMA_INT_STA_BT1, 0x000000FF);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_read(data, MTK_UDMA_INT_STA_BT1, &val);
+		if (err < 0)
+			return err;
 		msleep(100);
 	} else {
 		/* It's Device EndPoint Reset Option Register */
 		bt_dev_dbg(hdev, "Initiating reset mechanism via uhw");
-		btusb_mtk_uhw_reg_write(data, MTK_EP_RST_OPT, MTK_EP_RST_IN_OUT_OPT);
-		btusb_mtk_uhw_reg_read(data, MTK_BT_WDT_STATUS, &val);
-
+		err = btusb_mtk_uhw_reg_write(data, MTK_EP_RST_OPT, MTK_EP_RST_IN_OUT_OPT);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_read(data, MTK_BT_WDT_STATUS, &val);
+		if (err < 0)
+			return err;
 		/* Reset the bluetooth chip via USB interface. */
-		btusb_mtk_uhw_reg_write(data, MTK_BT_SUBSYS_RST, 1);
-		btusb_mtk_uhw_reg_write(data, MTK_UDMA_INT_STA_BT, 0x000000FF);
-		btusb_mtk_uhw_reg_read(data, MTK_UDMA_INT_STA_BT, &val);
-		btusb_mtk_uhw_reg_write(data, MTK_UDMA_INT_STA_BT1, 0x000000FF);
-		btusb_mtk_uhw_reg_read(data, MTK_UDMA_INT_STA_BT1, &val);
+		err = btusb_mtk_uhw_reg_write(data, MTK_BT_SUBSYS_RST, 1);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_write(data, MTK_UDMA_INT_STA_BT, 0x000000FF);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_read(data, MTK_UDMA_INT_STA_BT, &val);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_write(data, MTK_UDMA_INT_STA_BT1, 0x000000FF);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_read(data, MTK_UDMA_INT_STA_BT1, &val);
+		if (err < 0)
+			return err;
 		/* MT7921 need to delay 20ms between toggle reset bit */
 		msleep(20);
-		btusb_mtk_uhw_reg_write(data, MTK_BT_SUBSYS_RST, 0);
-		btusb_mtk_uhw_reg_read(data, MTK_BT_SUBSYS_RST, &val);
+		err = btusb_mtk_uhw_reg_write(data, MTK_BT_SUBSYS_RST, 0);
+		if (err < 0)
+			return err;
+		err = btusb_mtk_uhw_reg_read(data, MTK_BT_SUBSYS_RST, &val);
+		if (err < 0)
+			return err;
 	}
 
 	err = readx_poll_timeout(btusb_mtk_reset_done, hdev, val,
@@ -3085,11 +3134,14 @@ static int btusb_mtk_subsys_reset(struct hci_dev *hdev, u32 dev_id)
 	if (err < 0)
 		bt_dev_err(hdev, "Reset timeout");
 
-	if (dev_id == 0x7922)
-		btusb_mtk_uhw_reg_write(data, MTK_UDMA_INT_STA_BT, 0x000000FF);
+	if (dev_id == 0x7922) {
+		err = btusb_mtk_uhw_reg_write(data, MTK_UDMA_INT_STA_BT, 0x000000FF);
+		if (err < 0)
+			return err;
+	}
 
-	btusb_mtk_id_get(data, 0x70010200, &val);
-	if (!val)
+	err = btusb_mtk_id_get(data, 0x70010200, &val);
+	if (err < 0 || !val)
 		bt_dev_err(hdev, "Can't get device id, subsys reset fail.");
 
 	return err;
@@ -3205,7 +3257,9 @@ static int btusb_mtk_setup(struct hci_dev *hdev)
 		set_bit(BTUSB_FIRMWARE_LOADED, &data->flags);
 
 		/* It's Device EndPoint Reset Option Register */
-		btusb_mtk_uhw_reg_write(data, MTK_EP_RST_OPT, MTK_EP_RST_IN_OUT_OPT);
+		err = btusb_mtk_uhw_reg_write(data, MTK_EP_RST_OPT, MTK_EP_RST_IN_OUT_OPT);
+		if (err < 0)
+			return err;
 
 		/* Enable Bluetooth protocol */
 		param = 1;
-- 
2.25.1