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[PATCH] usbcore: port reset for composite devices

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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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern 2006-06-01 13:33:42 -04:00 • committed by Greg Kroah-Hartman
parent efcaa20525
commit 79efa097e7
4 changed files with 92 additions and 5 deletions
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84
drivers/usb/core/hub.c
View file

@ -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;
}