Bluetooth: btusb: Trigger Intel FW download error recovery

Sometimes during FW data download stage, in case of an error is
encountered the controller device could not be recovered. To recover
from such failures send Intel hard Reset to re-trigger FW download in
following error scenarios:

1. Intel Read version command error
2. Firmware download timeout
3. Failure in Intel Soft Reset for switching to operational FW
4. Boot timeout for switching to operaional FW

Signed-off-by: Raghuram Hegde <[e-mail]>
Signed-off-by: Chethan T N <[e-mail]>
Signed-off-by: Amit K Bag <[e-mail]>
Signed-off-by: Marcel Holtmann <[e-mail]>

drivers/bluetooth/btintel.c

···
 }
 EXPORT_SYMBOL_GPL(btintel_download_firmware);
 
+void btintel_reset_to_bootloader(struct hci_dev *hdev)
+{
+	struct intel_reset params;
+	struct sk_buff *skb;
+
+	/* Send Intel Reset command. This will result in
+	 * re-enumeration of BT controller.
+	 *
+	 * Intel Reset parameter description:
+	 * reset_type :   0x00 (Soft reset),
+	 *		  0x01 (Hard reset)
+	 * patch_enable : 0x00 (Do not enable),
+	 *		  0x01 (Enable)
+	 * ddc_reload :   0x00 (Do not reload),
+	 *		  0x01 (Reload)
+	 * boot_option:   0x00 (Current image),
+	 *                0x01 (Specified boot address)
+	 * boot_param:    Boot address
+	 *
+	 */
+	params.reset_type = 0x01;
+	params.patch_enable = 0x01;
+	params.ddc_reload = 0x01;
+	params.boot_option = 0x00;
+	params.boot_param = cpu_to_le32(0x00000000);
+
+	skb = __hci_cmd_sync(hdev, 0xfc01, sizeof(params),
+			     &params, HCI_INIT_TIMEOUT);
+	if (IS_ERR(skb)) {
+		bt_dev_err(hdev, "FW download error recovery failed (%ld)",
+			   PTR_ERR(skb));
+		return;
+	}
+	bt_dev_info(hdev, "Intel reset sent to retry FW download");
+	kfree_skb(skb);
+
+	/* Current Intel BT controllers(ThP/JfP) hold the USB reset
+	 * lines for 2ms when it receives Intel Reset in bootloader mode.
+	 * Whereas, the upcoming Intel BT controllers will hold USB reset
+	 * for 150ms. To keep the delay generic, 150ms is chosen here.
+	 */
+	msleep(150);
+}
+EXPORT_SYMBOL_GPL(btintel_reset_to_bootloader);
+
 MODULE_AUTHOR("Marcel Holtmann <[e-mail]>");
 MODULE_DESCRIPTION("Bluetooth support for Intel devices ver " VERSION);
 MODULE_VERSION(VERSION);

drivers/bluetooth/btintel.h

···
 			     struct intel_boot_params *params);
 int btintel_download_firmware(struct hci_dev *dev, const struct firmware *fw,
 			      u32 *boot_param);
+void btintel_reset_to_bootloader(struct hci_dev *hdev);
 #else
 
 static inline int btintel_check_bdaddr(struct hci_dev *hdev)
···
 static inline int btintel_download_firmware(struct hci_dev *dev,
 					    const struct firmware *fw,
 					    u32 *boot_param)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void btintel_reset_to_bootloader(struct hci_dev *hdev)
 {
 	return -EOPNOTSUPP;
 }

drivers/bluetooth/btusb.c

···
 	 * loaded.
 	 */
 	err = btintel_read_version(hdev, &ver);
-	if (err)
+	if (err) {
+		bt_dev_err(hdev, "Intel Read version failed (%d)", err);
+		btintel_reset_to_bootloader(hdev);
 		return err;
+	}
 
 	/* The hardware platform number has a fixed value of 0x37 and
 	 * for now only accept this single value.
···
 
 	/* Start firmware downloading and get boot parameter */
 	err = btintel_download_firmware(hdev, fw, &boot_param);
-	if (err < 0)
+	if (err < 0) {
+		/* When FW download fails, send Intel Reset to retry
+		 * FW download.
+		 */
+		btintel_reset_to_bootloader(hdev);
 		goto done;
-
+	}
 	set_bit(BTUSB_FIRMWARE_LOADED, &data->flags);
 
 	bt_dev_info(hdev, "Waiting for firmware download to complete");
···
 	if (err) {
 		bt_dev_err(hdev, "Firmware loading timeout");
 		err = -ETIMEDOUT;
+		btintel_reset_to_bootloader(hdev);
 		goto done;
 	}
 
···
 	set_bit(BTUSB_BOOTING, &data->flags);
 
 	err = btintel_send_intel_reset(hdev, boot_param);
-	if (err)
+	if (err) {
+		bt_dev_err(hdev, "Intel Soft Reset failed (%d)", err);
+		btintel_reset_to_bootloader(hdev);
 		return err;
+	}
 
 	/* The bootloader will not indicate when the device is ready. This
 	 * is done by the operational firmware sending bootup notification.
···
 
 	if (err) {
 		bt_dev_err(hdev, "Device boot timeout");
+		btintel_reset_to_bootloader(hdev);
 		return -ETIMEDOUT;
 	}