Bluetooth: btrtl: HCI reset on close for Realtek BT chip

Realtek RTL8822BE BT chip on ASUS X420FA cannot be turned on correctly
after on-off several times. Bluetooth daemon sets BT mode failed when
this issue happens. Scanning must be active while turning off for this
bug to be hit.

bluetoothd[1576]: Failed to set mode: Failed (0x03)

If BT is turned off, then turned on again, it works correctly again.

According to the vendor driver, the HCI_QUIRK_RESET_ON_CLOSE flag is set
during probing. So, this patch makes Realtek's BT reset on close to fix
this issue.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=203429
Signed-off-by: Jian-Hong Pan <jian-hong@endlessm.com>
Reviewed-by: Daniel Drake <drake@endlessm.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/btrtl.c

@@ -637,6 +637,26 @@ int btrtl_setup_realtek(struct hci_dev *hdev)
 }
 EXPORT_SYMBOL_GPL(btrtl_setup_realtek);
 
+int btrtl_shutdown_realtek(struct hci_dev *hdev)
+{
+	struct sk_buff *skb;
+	int ret;
+
+	/* According to the vendor driver, BT must be reset on close to avoid
+	 * firmware crash.
+	 */
+	skb = __hci_cmd_sync(hdev, HCI_OP_RESET, 0, NULL, HCI_INIT_TIMEOUT);
+	if (IS_ERR(skb)) {
+		ret = PTR_ERR(skb);
+		bt_dev_err(hdev, "HCI reset during shutdown failed");
+		return ret;
+	}
+	kfree_skb(skb);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(btrtl_shutdown_realtek);
+
 static unsigned int btrtl_convert_baudrate(u32 device_baudrate)
 {
 	switch (device_baudrate) {

drivers/bluetooth/btrtl.h

@@ -55,6 +55,7 @@ void btrtl_free(struct btrtl_device_info *btrtl_dev);
 int btrtl_download_firmware(struct hci_dev *hdev,
 			    struct btrtl_device_info *btrtl_dev);
 int btrtl_setup_realtek(struct hci_dev *hdev);
+int btrtl_shutdown_realtek(struct hci_dev *hdev);
 int btrtl_get_uart_settings(struct hci_dev *hdev,
 			    struct btrtl_device_info *btrtl_dev,
 			    unsigned int *controller_baudrate,
@@ -83,6 +84,11 @@ static inline int btrtl_setup_realtek(struct hci_dev *hdev)
 	return -EOPNOTSUPP;
 }
 
+static inline int btrtl_shutdown_realtek(struct hci_dev *hdev)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline int btrtl_get_uart_settings(struct hci_dev *hdev,
 					  struct btrtl_device_info *btrtl_dev,
 					  unsigned int *controller_baudrate,

drivers/bluetooth/btusb.c

@@ -3184,6 +3184,7 @@ static int btusb_probe(struct usb_interface *intf,
 #ifdef CONFIG_BT_HCIBTUSB_RTL
 	if (id->driver_info & BTUSB_REALTEK) {
 		hdev->setup = btrtl_setup_realtek;
+		hdev->shutdown = btrtl_shutdown_realtek;
 
 		/* Realtek devices lose their updated firmware over suspend,
 		 * but the USB hub doesn't notice any status change.