[PATCH] net: cdc_ether: allow combined control and data interface

[PATCH] net: cdc_ether: allow combined control and data interface

[Bjørn Mork]

Some Icera based Huawei modems handled by this driver are not
completely CDC ECM compliant, using the same USB interface for both
control and data. The CDC functional descriptors include a Union
naming this interface as both master and slave, so it is supportable
by relaxing the descriptor parsing in case these interfaces are
identical.

This has been tested on a Huawei K3806 and verified to add support
for that device.

Reported-and-tested-by: Enrico Mioso <mrkiko.rs@gmail.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
---
 drivers/net/usb/cdc_ether.c |   24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/net/usb/cdc_ether.c b/drivers/net/usb/cdc_ether.c
index 04ee044..7d88fef 100644
--- a/drivers/net/usb/cdc_ether.c
+++ b/drivers/net/usb/cdc_ether.c
@@ -215,6 +215,10 @@ int usbnet_generic_cdc_bind(struct usbnet *dev, struct usb_interface *intf)
 					goto bad_desc;
 			}
 
+			/* some devices merge these - skip class check */
+			if (info->control == info->data)
+				goto next_desc;
+
 			/* a data interface altsetting does the real i/o */
 			d = &info->data->cur_altsetting->desc;
 			if (d->bInterfaceClass != USB_CLASS_CDC_DATA) {
@@ -304,19 +308,23 @@ next_desc:
 	/* claim data interface and set it up ... with side effects.
 	 * network traffic can't flow until an altsetting is enabled.
 	 */
-	status = usb_driver_claim_interface(driver, info->data, dev);
-	if (status < 0)
-		return status;
+	if (info->data != info->control) {
+		status = usb_driver_claim_interface(driver, info->data, dev);
+		if (status < 0)
+			return status;
+	}
 	status = usbnet_get_endpoints(dev, info->data);
 	if (status < 0) {
 		/* ensure immediate exit from usbnet_disconnect */
 		usb_set_intfdata(info->data, NULL);
-		usb_driver_release_interface(driver, info->data);
+		if (info->data != info->control)
+			usb_driver_release_interface(driver, info->data);
 		return status;
 	}
 
 	/* status endpoint: optional for CDC Ethernet, not RNDIS (or ACM) */
-	dev->status = NULL;
+	if (info->data != info->control)
+		dev->status = NULL;
 	if (info->control->cur_altsetting->desc.bNumEndpoints == 1) {
 		struct usb_endpoint_descriptor	*desc;
 
@@ -353,7 +361,8 @@ void usbnet_cdc_unbind(struct usbnet *dev, struct usb_interface *intf)
 	if (intf == info->control && info->data) {
 		/* ensure immediate exit from usbnet_disconnect */
 		usb_set_intfdata(info->data, NULL);
-		usb_driver_release_interface(driver, info->data);
+		if (info->data != info->control)
+			usb_driver_release_interface(driver, info->data);
 		info->data = NULL;
 	}
 
@@ -361,7 +370,8 @@ void usbnet_cdc_unbind(struct usbnet *dev, struct usb_interface *intf)
 	else if (intf == info->data && info->control) {
 		/* ensure immediate exit from usbnet_disconnect */
 		usb_set_intfdata(info->control, NULL);
-		usb_driver_release_interface(driver, info->control);
+		if (info->data != info->control)
+			usb_driver_release_interface(driver, info->control);
 		info->control = NULL;
 	}
 }
-- 
1.7.10.4

Re: [PATCH] net: cdc_ether: allow combined control and data interface

[Oliver Neukum]

On Friday 28 June 2013 17:17:08 Bjørn Mork wrote:
> Some Icera based Huawei modems handled by this driver are not
> completely CDC ECM compliant, using the same USB interface for both
> control and data. The CDC functional descriptors include a Union
> naming this interface as both master and slave, so it is supportable
> by relaxing the descriptor parsing in case these interfaces are
> identical.

The disconnect handler is uselessly complex. Just return if the
interfaces are identical. There's nothing to do in that case.

	Regards
		Oliver

Re: [PATCH] net: cdc_ether: allow combined control and data interface

[Bjørn Mork]

Oliver Neukum <oliver@neukum.org> writes:

> On Friday 28 June 2013 17:17:08 Bjørn Mork wrote:
>> Some Icera based Huawei modems handled by this driver are not
>> completely CDC ECM compliant, using the same USB interface for both
>> control and data. The CDC functional descriptors include a Union
>> naming this interface as both master and slave, so it is supportable
>> by relaxing the descriptor parsing in case these interfaces are
>> identical.
>
> The disconnect handler is uselessly complex. Just return if the
> interfaces are identical. There's nothing to do in that case.

Right.  Thanks. Will post a new version cleaning that up.



Bjørn