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Commit 79efa097 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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[PATCH] usbcore: port reset for composite devices 



This patch (as699) adds usb_reset_composite_device(), a routine for
sending a USB port reset to a device with multiple interfaces owned by
different drivers.  Drivers are notified about impending and completed
resets through two new methods in the usb_driver structure.

The patch modifieds the usbfs ioctl code to make it use the new routine
instead of usb_reset_device().  Follow-up patches will modify the hub,
usb-storage, and usbhid drivers so they can utilize this new API.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent efcaa205

drivers/usb/core/devio.c

+1 −2
Original line number Diff line number Diff line
@@ -823,8 +823,7 @@ static int proc_connectinfo(struct dev_state *ps, void __user *arg) 


static int proc_resetdevice(struct dev_state *ps)

{

	return usb_reset_device(ps->dev);



	return usb_reset_composite_device(ps->dev, NULL);

}



static int proc_setintf(struct dev_state *ps, void __user *arg)

drivers/usb/core/hub.c

+81 −3
Original line number Diff line number Diff line
@@ -3007,9 +3007,9 @@ static int config_descriptors_changed(struct usb_device *udev) 
 * usb_reset_device - perform a USB port reset to reinitialize a device

 * @udev: device to reset (not in SUSPENDED or NOTATTACHED state)

 *

 * WARNING - don't reset any device unless drivers for all of its

 * interfaces are expecting that reset!  Maybe some driver->reset()

 * method should eventually help ensure sufficient cooperation.

 * WARNING - don't use this routine to reset a composite device

 * (one with multiple interfaces owned by separate drivers)!

 * Use usb_reset_composite_device() instead.

 *

 * Do a port reset, reassign the device's address, and establish its

 * former operating configuration.  If the reset fails, or the device's
@@ -3125,3 +3125,81 @@ re_enumerate: 
	hub_port_logical_disconnect(parent_hub, port1);

	return -ENODEV;

}



/**

 * usb_reset_composite_device - warn interface drivers and perform a USB port reset

 * @udev: device to reset (not in SUSPENDED or NOTATTACHED state)

 * @iface: interface bound to the driver making the request (optional)

 *

 * Warns all drivers bound to registered interfaces (using their pre_reset

 * method), performs the port reset, and then lets the drivers know that

 * the reset is over (using their post_reset method).

 *

 * Return value is the same as for usb_reset_device().

 *

 * The caller must own the device lock.  For example, it's safe to use

 * this from a driver probe() routine after downloading new firmware.

 * For calls that might not occur during probe(), drivers should lock

 * the device using usb_lock_device_for_reset().

 *

 * The interface locks are acquired during the pre_reset stage and released

 * during the post_reset stage.  However if iface is not NULL and is

 * currently being probed, we assume that the caller already owns its

 * lock.

 */

int usb_reset_composite_device(struct usb_device *udev,

		struct usb_interface *iface)

{

	int ret;

	struct usb_host_config *config = udev->actconfig;



	if (udev->state == USB_STATE_NOTATTACHED ||

			udev->state == USB_STATE_SUSPENDED) {

		dev_dbg(&udev->dev, "device reset not allowed in state %d\n",

				udev->state);

		return -EINVAL;

	}



	if (iface && iface->condition != USB_INTERFACE_BINDING)

		iface = NULL;



	if (config) {

		int i;

		struct usb_interface *cintf;

		struct usb_driver *drv;



		for (i = 0; i < config->desc.bNumInterfaces; ++i) {

			cintf = config->interface[i];

			if (cintf != iface)

				down(&cintf->dev.sem);

			if (device_is_registered(&cintf->dev) &&

					cintf->dev.driver) {

				drv = to_usb_driver(cintf->dev.driver);

				if (drv->pre_reset)

					(drv->pre_reset)(cintf);

			}

		}

	}



	ret = usb_reset_device(udev);



	if (config) {

		int i;

		struct usb_interface *cintf;

		struct usb_driver *drv;



		for (i = config->desc.bNumInterfaces - 1; i >= 0; --i) {

			cintf = config->interface[i];

			if (device_is_registered(&cintf->dev) &&

					cintf->dev.driver) {

				drv = to_usb_driver(cintf->dev.driver);

				if (drv->post_reset)

					(drv->post_reset)(cintf);

			}

			if (cintf != iface)

				up(&cintf->dev.sem);

		}

	}



	return ret;

}

drivers/usb/core/usb.c

+1 −0
Original line number Diff line number Diff line
@@ -1207,6 +1207,7 @@ EXPORT_SYMBOL(usb_ifnum_to_if); 
EXPORT_SYMBOL(usb_altnum_to_altsetting);



EXPORT_SYMBOL(usb_reset_device);

EXPORT_SYMBOL(usb_reset_composite_device);



EXPORT_SYMBOL(__usb_get_extra_descriptor);

include/linux/usb.h

+9 −0
Original line number Diff line number Diff line
@@ -386,6 +386,8 @@ extern int usb_lock_device_for_reset(struct usb_device *udev, 


/* USB port reset for device reinitialization */

extern int usb_reset_device(struct usb_device *dev);

extern int usb_reset_composite_device(struct usb_device *dev,

		struct usb_interface *iface);



extern struct usb_device *usb_find_device(u16 vendor_id, u16 product_id);
@@ -554,6 +556,10 @@ struct usb_dynids { 
 *	do (or don't) show up otherwise in the filesystem.

 * @suspend: Called when the device is going to be suspended by the system.

 * @resume: Called when the device is being resumed by the system.

 * @pre_reset: Called by usb_reset_composite_device() when the device

 *	is about to be reset.

 * @post_reset: Called by usb_reset_composite_device() after the device

 *	has been reset.

 * @id_table: USB drivers use ID table to support hotplugging.

 *	Export this with MODULE_DEVICE_TABLE(usb,...).  This must be set

 *	or your driver's probe function will never get called.
@@ -592,6 +598,9 @@ struct usb_driver { 
	int (*suspend) (struct usb_interface *intf, pm_message_t message);

	int (*resume) (struct usb_interface *intf);



	void (*pre_reset) (struct usb_interface *intf);

	void (*post_reset) (struct usb_interface *intf);



	const struct usb_device_id *id_table;



	struct usb_dynids dynids;