rndis_host: support WM6 devices as modems

This patch allows Windows Mobile 6 devices to be used for
tethering -- that is, used as modems.  It was requested by
AdamW in kernel bugzilla:

  http://bugzilla.kernel.org/show_bug.cgi?id=11119

and Mandriva kernel-discuss list.  It is tested and confirmed
to work by Peterl:

  http://forum.eeeuser.com/viewtopic.php?pid=323543#p323543

This patch is based on the patch in the above kernel bugzilla,
which is from the usb-rndis-lite tree.

[ dbrownell@users.sourceforge.net: misc fixes ]
Signed-off-by: Thomas Backlund <tmb@mandriva.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/net/usb/cdc_ether.c

@@ -50,10 +50,18 @@ static int is_activesync(struct usb_interface_descriptor *desc)
 		&& desc->bInterfaceProtocol == 1;
 }
 
+static int is_wireless_rndis(struct usb_interface_descriptor *desc)
+{
+	return desc->bInterfaceClass == USB_CLASS_WIRELESS_CONTROLLER
+		&& desc->bInterfaceSubClass == 1
+		&& desc->bInterfaceProtocol == 3;
+}
+
 #else
 
 #define is_rndis(desc)		0
 #define is_activesync(desc)	0
+#define is_wireless_rndis(desc)	0
 
 #endif
 
@@ -110,7 +118,8 @@ int usbnet_generic_cdc_bind(struct usbnet *dev, struct usb_interface *intf)
 	 * of cdc-acm, it'll fail RNDIS requests cleanly.
 	 */
 	rndis = is_rndis(&intf->cur_altsetting->desc)
-		|| is_activesync(&intf->cur_altsetting->desc);
+		|| is_activesync(&intf->cur_altsetting->desc)
+		|| is_wireless_rndis(&intf->cur_altsetting->desc);
 
 	memset(info, 0, sizeof *info);
 	info->control = intf;

drivers/net/usb/rndis_host.c

@@ -576,6 +576,10 @@ static const struct usb_device_id	products [] = {
 	/* "ActiveSync" is an undocumented variant of RNDIS, used in WM5 */
 	USB_INTERFACE_INFO(USB_CLASS_MISC, 1, 1),
 	.driver_info = (unsigned long) &rndis_info,
+}, {
+	/* RNDIS for tethering */
+	USB_INTERFACE_INFO(USB_CLASS_WIRELESS_CONTROLLER, 1, 3),
+	.driver_info = (unsigned long) &rndis_info,
 },
 	{ },		// END
 };