usb: renesas-xhci: Fix handling of unknown ROM state

commit d143825 upstream.

The ROM load sometimes seems to return an unknown status
(RENESAS_ROM_STATUS_NO_RESULT) instead of success / fail.

If the ROM load indeed failed this leads to failures when trying to
communicate with the controller later on.

Attempt to load firmware using RAM load in those cases.

Fixes: 2478be8 ("usb: renesas-xhci: Add ROM loader for uPD720201")
Cc: stable@vger.kernel.org
Cc: Mathias Nyman <mathias.nyman@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Vinod Koul <vkoul@kernel.org>
Tested-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Link: https://lore.kernel.org/r/20210615153758.253572-1-mdf@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-pci-renesas.c

@@ -207,7 +207,8 @@ static int renesas_check_rom_state(struct pci_dev *pdev)
 			return 0;
 
 		case RENESAS_ROM_STATUS_NO_RESULT: /* No result yet */
-			return 0;
+			dev_dbg(&pdev->dev, "Unknown ROM status ...\n");
+			break;
 
 		case RENESAS_ROM_STATUS_ERROR: /* Error State */
 		default: /* All other states are marked as "Reserved states" */
@@ -224,13 +225,12 @@ static int renesas_fw_check_running(struct pci_dev *pdev)
 	u8 fw_state;
 	int err;
 
-	/* Check if device has ROM and loaded, if so skip everything */
-	err = renesas_check_rom(pdev);
-	if (err) { /* we have rom */
-		err = renesas_check_rom_state(pdev);
-		if (!err)
-			return err;
-	}
+	/*
+	 * Only if device has ROM and loaded FW we can skip loading and
+	 * return success. Otherwise (even unknown state), attempt to load FW.
+	 */
+	if (renesas_check_rom(pdev) && !renesas_check_rom_state(pdev))
+		return 0;
 
 	/*
 	 * Test if the device is actually needing the firmware. As most