[PATCH] usbfs disconnect

This was originally created by David many months ago and posted to the
list, but not put into the kernel.

I modified the original patch to:
-patch against the 2.5.7 kernel
-use the 'real' interface number, not position (to do this I added 2
 methods in usb.c)

drivers/usb/core/devio.c

@@ -1057,6 +1057,8 @@ static int proc_ioctl (struct dev_state *ps, void *arg)
 	int			size;
 	void			*buf = 0;
 	int			retval = 0;
+       struct usb_interface    *ifp = 0;
+       struct usb_driver       *driver = 0;
 
 	/* get input parameters and alloc buffer */
 	if (copy_from_user(&ctrl, (void *) arg, sizeof (ctrl)))
@@ -1074,33 +1076,41 @@ static int proc_ioctl (struct dev_state *ps, void *arg)
 		}
 	}
 
-	/* ioctl to device */
-	if (ctrl.ifno < 0) {
-		switch (ctrl.ioctl_code) {
-		/* access/release token for issuing control messages
-		 * ask a particular driver to bind/unbind, ... etc
-		 */
-		}
-		retval = -ENOSYS;
-
-	/* ioctl to the driver which has claimed a given interface */
-	} else {
-		struct usb_interface	*ifp = 0;
        if (!ps->dev)
                retval = -ENODEV;
-		else if (ctrl.ifno >= ps->dev->actconfig->bNumInterfaces)
+       else if (!(ifp = usb_ifnum_to_if (ps->dev, ctrl.ifno)))
                retval = -EINVAL;
-		else {
-			if (!(ifp = usb_ifnum_to_if (ps->dev, ctrl.ifno)))
+       else switch (ctrl.ioctl_code) {
+
+       /* disconnect kernel driver from interface, leaving it unbound.  */
+       case USBDEVFS_DISCONNECT:
+               driver = ifp->driver;
+               if (driver) {
+                       down (&driver->serialize);
+                       dbg ("disconnect '%s' from dev %d interface %d",
+                               driver->name, ps->dev->devnum, ctrl.ifno);
+                       driver->disconnect (ps->dev, ifp->private_data);
+                       usb_driver_release_interface (driver, ifp);
+                       up (&driver->serialize);
+               } else
 			retval = -EINVAL;
-			else if (ifp->driver == 0 || ifp->driver->ioctl == 0)
+               break;
+
+       /* let kernel drivers try to (re)bind to the interface */
+       case USBDEVFS_CONNECT:
+               usb_find_interface_driver_for_ifnum (ps->dev, ctrl.ifno);
+               break;
+
+       /* talk directly to the interface's driver */
+       default:
+               driver = ifp->driver;
+               if (driver == 0 || driver->ioctl == 0)
                        retval = -ENOSYS;
-		}
-		if (retval == 0) {
+		else {
 			if (ifp->driver->owner)
 				__MOD_INC_USE_COUNT(ifp->driver->owner);
 			/* ifno might usefully be passed ... */
-			retval = ifp->driver->ioctl (ps->dev, ctrl.ioctl_code, buf);
+                       retval = driver->ioctl (ps->dev, ctrl.ioctl_code, buf);
 			/* size = min_t(int, size, retval)? */
 			if (ifp->driver->owner)
 				__MOD_DEC_USE_COUNT(ifp->driver->owner);

drivers/usb/core/usb.c

@@ -196,6 +196,26 @@ void usb_deregister(struct usb_driver *driver)
 	usbfs_update_special();
 }
 
+/*
+ * usb_ifnum_to_ifpos - convert the interface _number_ (as in interface.bInterfaceNumber)
+ * to the interface _position_ (as in dev->actconfig->interface + position)
+ * @dev: the device to use
+ * @ifnum: the interface number (bInterfaceNumber); not interface position
+ *
+ * Note that the number is the same as the position for all interfaces _except_
+ * devices with interfaces not sequentially numbered (e.g., 0, 2, 3, etc).
+ */
+int usb_ifnum_to_ifpos(struct usb_device *dev, unsigned ifnum)
+{
+	int i;
+
+	for (i = 0; i < dev->actconfig->bNumInterfaces; i++)
+		if (dev->actconfig->interface[i].altsetting[0].bInterfaceNumber == ifnum)
+			return i;
+
+	return -EINVAL;
+}
+
 /**
  * usb_ifnum_to_if - get the interface object with a given interface number
  * @dev: the device whose current configuration is considered
@@ -570,6 +590,23 @@ static int usb_find_interface_driver(struct usb_device *dev, unsigned ifnum)
 	return -1;
 }
 
+/*
+ * usb_find_interface_driver_for_ifnum - convert ifnum to ifpos via
+ * usb_ifnum_to_ifpos and call usb_find_interface_driver().
+ * @dev: the device to use
+ * @ifnum: the interface number (bInterfaceNumber); not interface position!
+ *
+ * Note usb_find_interface_driver's ifnum parameter is actually interface position.
+ */
+int usb_find_interface_driver_for_ifnum(struct usb_device *dev, unsigned ifnum)
+{
+	int ifpos = usb_ifnum_to_ifpos(dev, ifnum);
+
+	if (0 > ifpos)
+		return -EINVAL;
+
+	return usb_find_interface_driver(dev, ifpos);
+}
 
 #ifdef	CONFIG_HOTPLUG
 
@@ -2636,6 +2673,7 @@ module_exit(usb_exit);
  * into the kernel, and other device drivers are built as modules,
  * then these symbols need to be exported for the modules to use.
  */
+EXPORT_SYMBOL(usb_ifnum_to_ifpos);
 EXPORT_SYMBOL(usb_ifnum_to_if);
 EXPORT_SYMBOL(usb_epnum_to_ep_desc);
 
@@ -2647,6 +2685,7 @@ EXPORT_SYMBOL(usb_alloc_dev);
 EXPORT_SYMBOL(usb_free_dev);
 EXPORT_SYMBOL(usb_inc_dev_use);
 
+EXPORT_SYMBOL(usb_find_interface_driver_for_ifnum);
 EXPORT_SYMBOL(usb_driver_claim_interface);
 EXPORT_SYMBOL(usb_interface_claimed);
 EXPORT_SYMBOL(usb_driver_release_interface);

include/linux/usb.h

@@ -305,6 +305,7 @@ struct usb_qualifier_descriptor {
 } __attribute__ ((packed));
 
 /* helpers for driver access to descriptors */
+extern int usb_ifnum_to_ifpos(struct usb_device *dev, unsigned ifnum);
 extern struct usb_interface *
 	usb_ifnum_to_if(struct usb_device *dev, unsigned ifnum);
 extern struct usb_endpoint_descriptor *
@@ -1052,6 +1053,7 @@ extern void usb_inc_dev_use(struct usb_device *);
 #define usb_dec_dev_use usb_free_dev
 
 /* used these for multi-interface device registration */
+extern int usb_find_interface_driver_for_ifnum(struct usb_device *dev, unsigned int ifnum);
 extern void usb_driver_claim_interface(struct usb_driver *driver,
 			struct usb_interface *iface, void* priv);
 extern int usb_interface_claimed(struct usb_interface *iface);

include/linux/usbdevice_fs.h

@@ -142,6 +142,8 @@ struct usbdevfs_hub_portinfo {
 #define USBDEVFS_HUB_PORTINFO      _IOR('U', 19, struct usbdevfs_hub_portinfo)
 #define USBDEVFS_RESET             _IO('U', 20)
 #define USBDEVFS_CLEAR_HALT        _IOR('U', 21, unsigned int)
+#define USBDEVFS_DISCONNECT        _IO('U', 22)
+#define USBDEVFS_CONNECT           _IO('U', 23)
 
 /* --------------------------------------------------------------------- */