usb: Early failure when the first descriptor read fails or is invalid

This may happen when using an USB1 device on a controller that only supports
USB2 (e.g. EHCI). Reading the first descriptor will fail (read 0 byte), so we
can abort the process at this point instead of failing later and wasting time.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>

diff --git a/common/usb.c b/common/usb.c
index 6ed31240fef9543402c70ad1d067eb98eadeb70a..f6488475a7f22c5db1ef8d61ccd4043299751023 100644 (file)
--- a/common/usb.c
+++ b/common/usb.c
@@ -956,7 +956,7 @@ int usb_new_device(struct usb_device *dev)
         */
 #ifndef CONFIG_USB_XHCI
        err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, 64);
-       if (err < 0) {
+       if (err < sizeof(struct usb_device_descriptor)) {
                debug("usb_new_device: usb_get_descriptor() failed\n");
                return -EIO;
        }
@@ -996,6 +996,9 @@ int usb_new_device(struct usb_device *dev)
        case 64:
                dev->maxpacketsize = PACKET_SIZE_64;
                break;
+       default:
+               printf("usb_new_device: invalid max packet size\n");
+               return -EIO;
        }
        dev->devnum = addr;