fix USB devices with multiple configurations

This patch fixes bugs in usbdcore*.c related to the use of devices
with multiple configurations.

The original code made mistakes about the meaning of configuration value and
configuration index, and the resulting off-by-one errors resulted in:

* SET_CONFIGURATION always selected the first configuration, no matter what
  wValue is being passed.
* GET_DESCRIPTOR/CONFIGURATION always returned the descriptor for the first
  configuration (index 0).

Signed-off-by: Harald Welte <laforge@openmoko.org>
Acked-by: Markus Klotzbuecher <mk@denx.de>

drivers/usb/usbdcore.c

@@ -146,12 +146,9 @@ struct usb_string_descriptor *usbd_get_string (__u8 index)
 static struct usb_configuration_instance *usbd_device_configuration_instance (struct usb_device_instance *device,
 		unsigned int port, unsigned int configuration)
 {
-	/* XXX */
-	configuration = configuration ? configuration - 1 : 0;
-
-	if (configuration >= device->configurations) {
+	if (configuration >= device->configurations)
 		return NULL;
-	}
+
 	return device->configuration_instance_array + configuration;
 }
 

drivers/usb/usbdcore_ep0.c

@@ -235,8 +235,8 @@ static int ep0_get_descriptor (struct usb_device_instance *device,
 				return -1;
 			}
 			/*dbg_ep0(2, "%d %d", index, device_descriptor->bNumConfigurations); */
-			if (index > device_descriptor->bNumConfigurations) {
-				dbg_ep0 (0, "index too large: %d > %d", index,
+			if (index >= device_descriptor->bNumConfigurations) {
+				dbg_ep0 (0, "index too large: %d >= %d", index,
 					 device_descriptor->
 					 bNumConfigurations);
 				return -1;
@@ -571,14 +571,8 @@ int ep0_recv_setup (struct urb *urb)
 
 		case USB_REQ_SET_CONFIGURATION:
 			/* c.f. 9.4.7 - the top half of wValue is reserved */
-			/* */
-			if ((device->configuration =
-				le16_to_cpu (request->wValue) & 0xFF80) != 0) {
-				/* c.f. 9.4.7 - zero is the default or addressed state, in our case this */
-				/* is the same is configuration zero */
-				serial_printf("error setting dev->config to zero!\n");
-				device->configuration = 0;	/* TBR - ?????? */
-			}
+			device->configuration = le16_to_cpu(request->wValue) & 0xff;
+
 			/* reset interface and alternate settings */
 			device->interface = device->alternate = 0;