driver.c 46.7 KB
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/*
 * drivers/usb/driver.c - most of the driver model stuff for usb
 *
 * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
 *
 * based on drivers/usb/usb.c which had the following copyrights:
 *	(C) Copyright Linus Torvalds 1999
 *	(C) Copyright Johannes Erdfelt 1999-2001
 *	(C) Copyright Andreas Gal 1999
 *	(C) Copyright Gregory P. Smith 1999
 *	(C) Copyright Deti Fliegl 1999 (new USB architecture)
 *	(C) Copyright Randy Dunlap 2000
 *	(C) Copyright David Brownell 2000-2004
 *	(C) Copyright Yggdrasil Computing, Inc. 2000
 *		(usb_device_id matching changes by Adam J. Richter)
 *	(C) Copyright Greg Kroah-Hartman 2002-2003
 *
 * NOTE! This is not actually a driver at all, rather this is
 * just a collection of helper routines that implement the
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 * matching, probing, releasing, suspending and resuming for
 * real drivers.
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 *
 */

#include <linux/device.h>
#include <linux/usb.h>
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#include <linux/usb/quirks.h>
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#include <linux/workqueue.h>
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#include "hcd.h"
#include "usb.h"

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#ifdef CONFIG_HOTPLUG

/*
 * Adds a new dynamic USBdevice ID to this driver,
 * and cause the driver to probe for all devices again.
 */
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ssize_t usb_store_new_id(struct usb_dynids *dynids,
			 struct device_driver *driver,
			 const char *buf, size_t count)
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{
	struct usb_dynid *dynid;
	u32 idVendor = 0;
	u32 idProduct = 0;
	int fields = 0;
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	int retval = 0;
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	fields = sscanf(buf, "%x %x", &idVendor, &idProduct);
	if (fields < 2)
		return -EINVAL;

	dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
	if (!dynid)
		return -ENOMEM;

	INIT_LIST_HEAD(&dynid->node);
	dynid->id.idVendor = idVendor;
	dynid->id.idProduct = idProduct;
	dynid->id.match_flags = USB_DEVICE_ID_MATCH_DEVICE;

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	spin_lock(&dynids->lock);
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	list_add_tail(&dynid->node, &dynids->list);
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	spin_unlock(&dynids->lock);
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	if (get_driver(driver)) {
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		retval = driver_attach(driver);
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		put_driver(driver);
	}

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	if (retval)
		return retval;
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	return count;
}
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EXPORT_SYMBOL_GPL(usb_store_new_id);

static ssize_t store_new_id(struct device_driver *driver,
			    const char *buf, size_t count)
{
	struct usb_driver *usb_drv = to_usb_driver(driver);

	return usb_store_new_id(&usb_drv->dynids, driver, buf, count);
}
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static DRIVER_ATTR(new_id, S_IWUSR, NULL, store_new_id);

static int usb_create_newid_file(struct usb_driver *usb_drv)
{
	int error = 0;

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	if (usb_drv->no_dynamic_id)
		goto exit;

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	if (usb_drv->probe != NULL)
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		error = driver_create_file(&usb_drv->drvwrap.driver,
					   &driver_attr_new_id);
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exit:
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	return error;
}

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static void usb_remove_newid_file(struct usb_driver *usb_drv)
{
	if (usb_drv->no_dynamic_id)
		return;

	if (usb_drv->probe != NULL)
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		driver_remove_file(&usb_drv->drvwrap.driver,
				   &driver_attr_new_id);
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}

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static void usb_free_dynids(struct usb_driver *usb_drv)
{
	struct usb_dynid *dynid, *n;

	spin_lock(&usb_drv->dynids.lock);
	list_for_each_entry_safe(dynid, n, &usb_drv->dynids.list, node) {
		list_del(&dynid->node);
		kfree(dynid);
	}
	spin_unlock(&usb_drv->dynids.lock);
}
#else
static inline int usb_create_newid_file(struct usb_driver *usb_drv)
{
	return 0;
}

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static void usb_remove_newid_file(struct usb_driver *usb_drv)
{
}

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static inline void usb_free_dynids(struct usb_driver *usb_drv)
{
}
#endif

static const struct usb_device_id *usb_match_dynamic_id(struct usb_interface *intf,
							struct usb_driver *drv)
{
	struct usb_dynid *dynid;

	spin_lock(&drv->dynids.lock);
	list_for_each_entry(dynid, &drv->dynids.list, node) {
		if (usb_match_one_id(intf, &dynid->id)) {
			spin_unlock(&drv->dynids.lock);
			return &dynid->id;
		}
	}
	spin_unlock(&drv->dynids.lock);
	return NULL;
}


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/* called from driver core with dev locked */
static int usb_probe_device(struct device *dev)
{
	struct usb_device_driver *udriver = to_usb_device_driver(dev->driver);
	struct usb_device *udev;
	int error = -ENODEV;

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	dev_dbg(dev, "%s\n", __func__);
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	if (!is_usb_device(dev))	/* Sanity check */
		return error;

	udev = to_usb_device(dev);

	/* TODO: Add real matching code */

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	/* The device should always appear to be in use
	 * unless the driver suports autosuspend.
	 */
	udev->pm_usage_cnt = !(udriver->supports_autosuspend);

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	error = udriver->probe(udev);
	return error;
}

/* called from driver core with dev locked */
static int usb_unbind_device(struct device *dev)
{
	struct usb_device_driver *udriver = to_usb_device_driver(dev->driver);

	udriver->disconnect(to_usb_device(dev));
	return 0;
}


/* called from driver core with dev locked */
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static int usb_probe_interface(struct device *dev)
{
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	struct usb_driver *driver = to_usb_driver(dev->driver);
	struct usb_interface *intf;
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	struct usb_device *udev;
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	const struct usb_device_id *id;
	int error = -ENODEV;

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	dev_dbg(dev, "%s\n", __func__);
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	if (is_usb_device(dev))		/* Sanity check */
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		return error;
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	intf = to_usb_interface(dev);
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	udev = interface_to_usbdev(intf);
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	if (udev->authorized == 0) {
		dev_err(&intf->dev, "Device is not authorized for usage\n");
		return -ENODEV;
	}
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	id = usb_match_id(intf, driver->id_table);
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	if (!id)
		id = usb_match_dynamic_id(intf, driver);
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	if (id) {
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		dev_dbg(dev, "%s - got id\n", __func__);
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		error = usb_autoresume_device(udev);
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		if (error)
			return error;

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		/* Interface "power state" doesn't correspond to any hardware
		 * state whatsoever.  We use it to record when it's bound to
		 * a driver that may start I/0:  it's not frozen/quiesced.
		 */
		mark_active(intf);
		intf->condition = USB_INTERFACE_BINDING;
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		/* The interface should always appear to be in use
		 * unless the driver suports autosuspend.
		 */
		intf->pm_usage_cnt = !(driver->supports_autosuspend);

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		error = driver->probe(intf, id);
		if (error) {
			mark_quiesced(intf);
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			intf->needs_remote_wakeup = 0;
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			intf->condition = USB_INTERFACE_UNBOUND;
		} else
			intf->condition = USB_INTERFACE_BOUND;
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		usb_autosuspend_device(udev);
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	}

	return error;
}

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/* called from driver core with dev locked */
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static int usb_unbind_interface(struct device *dev)
{
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	struct usb_driver *driver = to_usb_driver(dev->driver);
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	struct usb_interface *intf = to_usb_interface(dev);
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	struct usb_device *udev;
	int error;
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	intf->condition = USB_INTERFACE_UNBINDING;

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	/* Autoresume for set_interface call below */
	udev = interface_to_usbdev(intf);
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	error = usb_autoresume_device(udev);
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	/* release all urbs for this interface */
	usb_disable_interface(interface_to_usbdev(intf), intf);

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	driver->disconnect(intf);
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	/* reset other interface state */
	usb_set_interface(interface_to_usbdev(intf),
			intf->altsetting[0].desc.bInterfaceNumber,
			0);
	usb_set_intfdata(intf, NULL);
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	intf->condition = USB_INTERFACE_UNBOUND;
	mark_quiesced(intf);
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	intf->needs_remote_wakeup = 0;

	if (!error)
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		usb_autosuspend_device(udev);
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	return 0;
}

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/**
 * usb_driver_claim_interface - bind a driver to an interface
 * @driver: the driver to be bound
 * @iface: the interface to which it will be bound; must be in the
 *	usb device's active configuration
 * @priv: driver data associated with that interface
 *
 * This is used by usb device drivers that need to claim more than one
 * interface on a device when probing (audio and acm are current examples).
 * No device driver should directly modify internal usb_interface or
 * usb_device structure members.
 *
 * Few drivers should need to use this routine, since the most natural
 * way to bind to an interface is to return the private data from
 * the driver's probe() method.
 *
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 * Callers must own the device lock, so driver probe() entries don't need
 * extra locking, but other call contexts may need to explicitly claim that
 * lock.
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 */
int usb_driver_claim_interface(struct usb_driver *driver,
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				struct usb_interface *iface, void *priv)
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{
	struct device *dev = &iface->dev;
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	struct usb_device *udev = interface_to_usbdev(iface);
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	int retval = 0;
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	if (dev->driver)
		return -EBUSY;

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	dev->driver = &driver->drvwrap.driver;
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	usb_set_intfdata(iface, priv);
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	usb_pm_lock(udev);
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	iface->condition = USB_INTERFACE_BOUND;
	mark_active(iface);
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	iface->pm_usage_cnt = !(driver->supports_autosuspend);
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	usb_pm_unlock(udev);
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	/* if interface was already added, bind now; else let
	 * the future device_add() bind it, bypassing probe()
	 */
	if (device_is_registered(dev))
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		retval = device_bind_driver(dev);
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	return retval;
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}
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EXPORT_SYMBOL_GPL(usb_driver_claim_interface);
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/**
 * usb_driver_release_interface - unbind a driver from an interface
 * @driver: the driver to be unbound
 * @iface: the interface from which it will be unbound
 *
 * This can be used by drivers to release an interface without waiting
 * for their disconnect() methods to be called.  In typical cases this
 * also causes the driver disconnect() method to be called.
 *
 * This call is synchronous, and may not be used in an interrupt context.
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 * Callers must own the device lock, so driver disconnect() entries don't
 * need extra locking, but other call contexts may need to explicitly claim
 * that lock.
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 */
void usb_driver_release_interface(struct usb_driver *driver,
					struct usb_interface *iface)
{
	struct device *dev = &iface->dev;
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	struct usb_device *udev = interface_to_usbdev(iface);
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	/* this should never happen, don't release something that's not ours */
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	if (!dev->driver || dev->driver != &driver->drvwrap.driver)
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		return;

	/* don't release from within disconnect() */
	if (iface->condition != USB_INTERFACE_BOUND)
		return;

	/* don't release if the interface hasn't been added yet */
	if (device_is_registered(dev)) {
		iface->condition = USB_INTERFACE_UNBINDING;
		device_release_driver(dev);
	}

	dev->driver = NULL;
	usb_set_intfdata(iface, NULL);
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	usb_pm_lock(udev);
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	iface->condition = USB_INTERFACE_UNBOUND;
	mark_quiesced(iface);
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	iface->needs_remote_wakeup = 0;
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	usb_pm_unlock(udev);
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}
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EXPORT_SYMBOL_GPL(usb_driver_release_interface);
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/* returns 0 if no match, 1 if match */
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int usb_match_device(struct usb_device *dev, const struct usb_device_id *id)
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{
	if ((id->match_flags & USB_DEVICE_ID_MATCH_VENDOR) &&
	    id->idVendor != le16_to_cpu(dev->descriptor.idVendor))
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_PRODUCT) &&
	    id->idProduct != le16_to_cpu(dev->descriptor.idProduct))
		return 0;

	/* No need to test id->bcdDevice_lo != 0, since 0 is never
	   greater than any unsigned number. */
	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_LO) &&
	    (id->bcdDevice_lo > le16_to_cpu(dev->descriptor.bcdDevice)))
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_HI) &&
	    (id->bcdDevice_hi < le16_to_cpu(dev->descriptor.bcdDevice)))
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_CLASS) &&
	    (id->bDeviceClass != dev->descriptor.bDeviceClass))
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_SUBCLASS) &&
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	    (id->bDeviceSubClass != dev->descriptor.bDeviceSubClass))
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		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_PROTOCOL) &&
	    (id->bDeviceProtocol != dev->descriptor.bDeviceProtocol))
		return 0;

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	return 1;
}

/* returns 0 if no match, 1 if match */
int usb_match_one_id(struct usb_interface *interface,
		     const struct usb_device_id *id)
{
	struct usb_host_interface *intf;
	struct usb_device *dev;

	/* proc_connectinfo in devio.c may call us with id == NULL. */
	if (id == NULL)
		return 0;

	intf = interface->cur_altsetting;
	dev = interface_to_usbdev(interface);

	if (!usb_match_device(dev, id))
		return 0;

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	/* The interface class, subclass, and protocol should never be
	 * checked for a match if the device class is Vendor Specific,
	 * unless the match record specifies the Vendor ID. */
	if (dev->descriptor.bDeviceClass == USB_CLASS_VENDOR_SPEC &&
			!(id->match_flags & USB_DEVICE_ID_MATCH_VENDOR) &&
			(id->match_flags & (USB_DEVICE_ID_MATCH_INT_CLASS |
				USB_DEVICE_ID_MATCH_INT_SUBCLASS |
				USB_DEVICE_ID_MATCH_INT_PROTOCOL)))
		return 0;

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	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_CLASS) &&
	    (id->bInterfaceClass != intf->desc.bInterfaceClass))
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_SUBCLASS) &&
	    (id->bInterfaceSubClass != intf->desc.bInterfaceSubClass))
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_PROTOCOL) &&
	    (id->bInterfaceProtocol != intf->desc.bInterfaceProtocol))
		return 0;

	return 1;
}
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EXPORT_SYMBOL_GPL(usb_match_one_id);

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/**
 * usb_match_id - find first usb_device_id matching device or interface
 * @interface: the interface of interest
 * @id: array of usb_device_id structures, terminated by zero entry
 *
 * usb_match_id searches an array of usb_device_id's and returns
 * the first one matching the device or interface, or null.
 * This is used when binding (or rebinding) a driver to an interface.
 * Most USB device drivers will use this indirectly, through the usb core,
 * but some layered driver frameworks use it directly.
 * These device tables are exported with MODULE_DEVICE_TABLE, through
 * modutils, to support the driver loading functionality of USB hotplugging.
 *
 * What Matches:
 *
 * The "match_flags" element in a usb_device_id controls which
 * members are used.  If the corresponding bit is set, the
 * value in the device_id must match its corresponding member
 * in the device or interface descriptor, or else the device_id
 * does not match.
 *
 * "driver_info" is normally used only by device drivers,
 * but you can create a wildcard "matches anything" usb_device_id
 * as a driver's "modules.usbmap" entry if you provide an id with
 * only a nonzero "driver_info" field.  If you do this, the USB device
 * driver's probe() routine should use additional intelligence to
 * decide whether to bind to the specified interface.
 *
 * What Makes Good usb_device_id Tables:
 *
 * The match algorithm is very simple, so that intelligence in
 * driver selection must come from smart driver id records.
 * Unless you have good reasons to use another selection policy,
 * provide match elements only in related groups, and order match
 * specifiers from specific to general.  Use the macros provided
 * for that purpose if you can.
 *
 * The most specific match specifiers use device descriptor
 * data.  These are commonly used with product-specific matches;
 * the USB_DEVICE macro lets you provide vendor and product IDs,
 * and you can also match against ranges of product revisions.
 * These are widely used for devices with application or vendor
 * specific bDeviceClass values.
 *
 * Matches based on device class/subclass/protocol specifications
 * are slightly more general; use the USB_DEVICE_INFO macro, or
 * its siblings.  These are used with single-function devices
 * where bDeviceClass doesn't specify that each interface has
 * its own class.
 *
 * Matches based on interface class/subclass/protocol are the
 * most general; they let drivers bind to any interface on a
 * multiple-function device.  Use the USB_INTERFACE_INFO
 * macro, or its siblings, to match class-per-interface style
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 * devices (as recorded in bInterfaceClass).
 *
 * Note that an entry created by USB_INTERFACE_INFO won't match
 * any interface if the device class is set to Vendor-Specific.
 * This is deliberate; according to the USB spec the meanings of
 * the interface class/subclass/protocol for these devices are also
 * vendor-specific, and hence matching against a standard product
 * class wouldn't work anyway.  If you really want to use an
 * interface-based match for such a device, create a match record
 * that also specifies the vendor ID.  (Unforunately there isn't a
 * standard macro for creating records like this.)
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 *
 * Within those groups, remember that not all combinations are
 * meaningful.  For example, don't give a product version range
 * without vendor and product IDs; or specify a protocol without
 * its associated class and subclass.
 */
const struct usb_device_id *usb_match_id(struct usb_interface *interface,
					 const struct usb_device_id *id)
{
	/* proc_connectinfo in devio.c may call us with id == NULL. */
	if (id == NULL)
		return NULL;

	/* It is important to check that id->driver_info is nonzero,
	   since an entry that is all zeroes except for a nonzero
	   id->driver_info is the way to create an entry that
	   indicates that the driver want to examine every
	   device and interface. */
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	for (; id->idVendor || id->idProduct || id->bDeviceClass ||
	       id->bInterfaceClass || id->driver_info; id++) {
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		if (usb_match_one_id(interface, id))
			return id;
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	}

	return NULL;
}
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EXPORT_SYMBOL_GPL(usb_match_id);
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static int usb_device_match(struct device *dev, struct device_driver *drv)
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{
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	/* devices and interfaces are handled separately */
	if (is_usb_device(dev)) {
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		/* interface drivers never match devices */
		if (!is_usb_device_driver(drv))
			return 0;
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		/* TODO: Add real matching code */
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		return 1;

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	} else {
		struct usb_interface *intf;
		struct usb_driver *usb_drv;
		const struct usb_device_id *id;

		/* device drivers never match interfaces */
		if (is_usb_device_driver(drv))
			return 0;

		intf = to_usb_interface(dev);
		usb_drv = to_usb_driver(drv);

		id = usb_match_id(intf, usb_drv->id_table);
		if (id)
			return 1;

		id = usb_match_dynamic_id(intf, usb_drv);
		if (id)
			return 1;
	}

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	return 0;
}

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#ifdef	CONFIG_HOTPLUG
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static int usb_uevent(struct device *dev, struct kobj_uevent_env *env)
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{
	struct usb_device *usb_dev;

	/* driver is often null here; dev_dbg() would oops */
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	pr_debug("usb %s: uevent\n", dev_name(dev));
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	if (is_usb_device(dev))
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		usb_dev = to_usb_device(dev);
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	else {
		struct usb_interface *intf = to_usb_interface(dev);
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		usb_dev = interface_to_usbdev(intf);
	}
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	if (usb_dev->devnum < 0) {
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		pr_debug("usb %s: already deleted?\n", dev_name(dev));
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		return -ENODEV;
	}
	if (!usb_dev->bus) {
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		pr_debug("usb %s: bus removed?\n", dev_name(dev));
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		return -ENODEV;
	}

#ifdef	CONFIG_USB_DEVICEFS
	/* If this is available, userspace programs can directly read
	 * all the device descriptors we don't tell them about.  Or
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	 * act as usermode drivers.
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	 */
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	if (add_uevent_var(env, "DEVICE=/proc/bus/usb/%03d/%03d",
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			   usb_dev->bus->busnum, usb_dev->devnum))
		return -ENOMEM;
#endif

	/* per-device configurations are common */
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	if (add_uevent_var(env, "PRODUCT=%x/%x/%x",
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			   le16_to_cpu(usb_dev->descriptor.idVendor),
			   le16_to_cpu(usb_dev->descriptor.idProduct),
			   le16_to_cpu(usb_dev->descriptor.bcdDevice)))
		return -ENOMEM;

	/* class-based driver binding models */
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	if (add_uevent_var(env, "TYPE=%d/%d/%d",
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			   usb_dev->descriptor.bDeviceClass,
			   usb_dev->descriptor.bDeviceSubClass,
			   usb_dev->descriptor.bDeviceProtocol))
		return -ENOMEM;

	return 0;
}

#else

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static int usb_uevent(struct device *dev, struct kobj_uevent_env *env)
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{
	return -ENODEV;
}
#endif	/* CONFIG_HOTPLUG */

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/**
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 * usb_register_device_driver - register a USB device (not interface) driver
 * @new_udriver: USB operations for the device driver
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 * @owner: module owner of this driver.
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 *
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 * Registers a USB device driver with the USB core.  The list of
 * unattached devices will be rescanned whenever a new driver is
 * added, allowing the new driver to attach to any recognized devices.
 * Returns a negative error code on failure and 0 on success.
 */
int usb_register_device_driver(struct usb_device_driver *new_udriver,
		struct module *owner)
{
	int retval = 0;

	if (usb_disabled())
		return -ENODEV;

	new_udriver->drvwrap.for_devices = 1;
	new_udriver->drvwrap.driver.name = (char *) new_udriver->name;
	new_udriver->drvwrap.driver.bus = &usb_bus_type;
	new_udriver->drvwrap.driver.probe = usb_probe_device;
	new_udriver->drvwrap.driver.remove = usb_unbind_device;
	new_udriver->drvwrap.driver.owner = owner;

	retval = driver_register(&new_udriver->drvwrap.driver);

	if (!retval) {
		pr_info("%s: registered new device driver %s\n",
			usbcore_name, new_udriver->name);
		usbfs_update_special();
	} else {
		printk(KERN_ERR "%s: error %d registering device "
			"	driver %s\n",
			usbcore_name, retval, new_udriver->name);
	}

	return retval;
}
EXPORT_SYMBOL_GPL(usb_register_device_driver);

/**
 * usb_deregister_device_driver - unregister a USB device (not interface) driver
 * @udriver: USB operations of the device driver to unregister
 * Context: must be able to sleep
 *
 * Unlinks the specified driver from the internal USB driver list.
 */
void usb_deregister_device_driver(struct usb_device_driver *udriver)
{
	pr_info("%s: deregistering device driver %s\n",
			usbcore_name, udriver->name);

	driver_unregister(&udriver->drvwrap.driver);
	usbfs_update_special();
}
EXPORT_SYMBOL_GPL(usb_deregister_device_driver);

/**
 * usb_register_driver - register a USB interface driver
 * @new_driver: USB operations for the interface driver
 * @owner: module owner of this driver.
R
Randy Dunlap 已提交
704
 * @mod_name: module name string
705 706 707 708
 *
 * Registers a USB interface driver with the USB core.  The list of
 * unattached interfaces will be rescanned whenever a new driver is
 * added, allowing the new driver to attach to any recognized interfaces.
709 710 711 712 713 714
 * Returns a negative error code on failure and 0 on success.
 *
 * NOTE: if you want your driver to use the USB major number, you must call
 * usb_register_dev() to enable that functionality.  This function no longer
 * takes care of that.
 */
715 716
int usb_register_driver(struct usb_driver *new_driver, struct module *owner,
			const char *mod_name)
717 718 719 720 721 722
{
	int retval = 0;

	if (usb_disabled())
		return -ENODEV;

723 724 725 726 727 728
	new_driver->drvwrap.for_devices = 0;
	new_driver->drvwrap.driver.name = (char *) new_driver->name;
	new_driver->drvwrap.driver.bus = &usb_bus_type;
	new_driver->drvwrap.driver.probe = usb_probe_interface;
	new_driver->drvwrap.driver.remove = usb_unbind_interface;
	new_driver->drvwrap.driver.owner = owner;
729
	new_driver->drvwrap.driver.mod_name = mod_name;
730 731
	spin_lock_init(&new_driver->dynids.lock);
	INIT_LIST_HEAD(&new_driver->dynids.list);
732

733
	retval = driver_register(&new_driver->drvwrap.driver);
734 735

	if (!retval) {
736
		pr_info("%s: registered new interface driver %s\n",
737 738
			usbcore_name, new_driver->name);
		usbfs_update_special();
739
		usb_create_newid_file(new_driver);
740
	} else {
741 742
		printk(KERN_ERR "%s: error %d registering interface "
			"	driver %s\n",
743 744 745 746 747
			usbcore_name, retval, new_driver->name);
	}

	return retval;
}
748
EXPORT_SYMBOL_GPL(usb_register_driver);
749 750

/**
751 752
 * usb_deregister - unregister a USB interface driver
 * @driver: USB operations of the interface driver to unregister
753 754 755 756 757 758 759 760 761 762
 * Context: must be able to sleep
 *
 * Unlinks the specified driver from the internal USB driver list.
 *
 * NOTE: If you called usb_register_dev(), you still need to call
 * usb_deregister_dev() to clean up your driver's allocated minor numbers,
 * this * call will no longer do it for you.
 */
void usb_deregister(struct usb_driver *driver)
{
763 764
	pr_info("%s: deregistering interface driver %s\n",
			usbcore_name, driver->name);
765

766
	usb_remove_newid_file(driver);
767
	usb_free_dynids(driver);
768
	driver_unregister(&driver->drvwrap.driver);
769 770 771

	usbfs_update_special();
}
772
EXPORT_SYMBOL_GPL(usb_deregister);
773 774 775

#ifdef CONFIG_PM

776
/* Caller has locked udev's pm_mutex */
777
static int usb_suspend_device(struct usb_device *udev, pm_message_t msg)
778
{
779
	struct usb_device_driver	*udriver;
780
	int				status = 0;
781

782 783 784 785
	if (udev->state == USB_STATE_NOTATTACHED ||
			udev->state == USB_STATE_SUSPENDED)
		goto done;

786 787 788 789
	/* For devices that don't have a driver, we do a generic suspend. */
	if (udev->dev.driver)
		udriver = to_usb_device_driver(udev->dev.driver);
	else {
790
		udev->do_remote_wakeup = 0;
791
		udriver = &usb_generic_driver;
792
	}
793 794
	status = udriver->suspend(udev, msg);

A
Alan Stern 已提交
795
 done:
796
	dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
797
	return status;
798 799
}

800
/* Caller has locked udev's pm_mutex */
801
static int usb_resume_device(struct usb_device *udev)
802 803
{
	struct usb_device_driver	*udriver;
804
	int				status = 0;
805

A
Alan Stern 已提交
806 807
	if (udev->state == USB_STATE_NOTATTACHED)
		goto done;
808

809 810 811
	/* Can't resume it if it doesn't have a driver. */
	if (udev->dev.driver == NULL) {
		status = -ENOTCONN;
812
		goto done;
813 814
	}

A
Alan Stern 已提交
815 816 817
	if (udev->quirks & USB_QUIRK_RESET_RESUME)
		udev->reset_resume = 1;

818
	udriver = to_usb_device_driver(udev->dev.driver);
819 820
	status = udriver->resume(udev);

A
Alan Stern 已提交
821
 done:
822
	dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
A
Alan Stern 已提交
823
	if (status == 0)
824
		udev->autoresume_disabled = 0;
825
	return status;
826 827
}

828
/* Caller has locked intf's usb_device's pm mutex */
829
static int usb_suspend_interface(struct usb_interface *intf, pm_message_t msg)
830 831
{
	struct usb_driver	*driver;
832
	int			status = 0;
833

834 835 836
	/* with no hardware, USB interfaces only use FREEZE and ON states */
	if (interface_to_usbdev(intf)->state == USB_STATE_NOTATTACHED ||
			!is_active(intf))
837
		goto done;
838

839
	if (intf->condition == USB_INTERFACE_UNBOUND)	/* This can't happen */
840
		goto done;
841
	driver = to_usb_driver(intf->dev.driver);
842 843

	if (driver->suspend && driver->resume) {
844
		status = driver->suspend(intf, msg);
845 846 847
		if (status == 0)
			mark_quiesced(intf);
		else if (!interface_to_usbdev(intf)->auto_pm)
848 849
			dev_err(&intf->dev, "%s error %d\n",
					"suspend", status);
850
	} else {
851 852 853 854
		/*
		 * FIXME else if there's no suspend method, disconnect...
		 * Not possible if auto_pm is set...
		 */
855 856
		dev_warn(&intf->dev, "no suspend for driver %s?\n",
				driver->name);
857 858
		mark_quiesced(intf);
	}
859

A
Alan Stern 已提交
860
 done:
861
	dev_vdbg(&intf->dev, "%s: status %d\n", __func__, status);
862 863 864
	return status;
}

865
/* Caller has locked intf's usb_device's pm_mutex */
A
Alan Stern 已提交
866
static int usb_resume_interface(struct usb_interface *intf, int reset_resume)
867
{
868
	struct usb_driver	*driver;
869
	int			status = 0;
870

871 872
	if (interface_to_usbdev(intf)->state == USB_STATE_NOTATTACHED ||
			is_active(intf))
873
		goto done;
874

875 876 877 878
	/* Don't let autoresume interfere with unbinding */
	if (intf->condition == USB_INTERFACE_UNBINDING)
		goto done;

879
	/* Can't resume it if it doesn't have a driver. */
880
	if (intf->condition == USB_INTERFACE_UNBOUND) {
881
		status = -ENOTCONN;
882
		goto done;
883
	}
884
	driver = to_usb_driver(intf->dev.driver);
885

A
Alan Stern 已提交
886 887 888 889 890 891 892
	if (reset_resume) {
		if (driver->reset_resume) {
			status = driver->reset_resume(intf);
			if (status)
				dev_err(&intf->dev, "%s error %d\n",
						"reset_resume", status);
		} else {
893
			/* status = -EOPNOTSUPP; */
A
Alan Stern 已提交
894 895 896 897 898 899 900 901 902 903
			dev_warn(&intf->dev, "no %s for driver %s?\n",
					"reset_resume", driver->name);
		}
	} else {
		if (driver->resume) {
			status = driver->resume(intf);
			if (status)
				dev_err(&intf->dev, "%s error %d\n",
						"resume", status);
		} else {
904
			/* status = -EOPNOTSUPP; */
A
Alan Stern 已提交
905 906 907 908
			dev_warn(&intf->dev, "no %s for driver %s?\n",
					"resume", driver->name);
		}
	}
909 910

done:
911
	dev_vdbg(&intf->dev, "%s: status %d\n", __func__, status);
A
Alan Stern 已提交
912 913
	if (status == 0)
		mark_active(intf);
A
Alan Stern 已提交
914 915 916

	/* FIXME: Unbind the driver and reprobe if the resume failed
	 * (not possible if auto_pm is set) */
917
	return status;
918 919
}

920 921
#ifdef	CONFIG_USB_SUSPEND

A
Alan Stern 已提交
922
/* Internal routine to check whether we may autosuspend a device. */
923
static int autosuspend_check(struct usb_device *udev, int reschedule)
A
Alan Stern 已提交
924 925 926
{
	int			i;
	struct usb_interface	*intf;
927
	unsigned long		suspend_time, j;
A
Alan Stern 已提交
928

929 930 931 932
	/* For autosuspend, fail fast if anything is in use or autosuspend
	 * is disabled.  Also fail if any interfaces require remote wakeup
	 * but it isn't available.
	 */
A
Alan Stern 已提交
933 934
	if (udev->pm_usage_cnt > 0)
		return -EBUSY;
935
	if (udev->autosuspend_delay < 0 || udev->autosuspend_disabled)
936 937
		return -EPERM;

938
	suspend_time = udev->last_busy + udev->autosuspend_delay;
A
Alan Stern 已提交
939 940 941 942 943 944 945 946 947 948 949 950 951
	if (udev->actconfig) {
		for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
			intf = udev->actconfig->interface[i];
			if (!is_active(intf))
				continue;
			if (intf->pm_usage_cnt > 0)
				return -EBUSY;
			if (intf->needs_remote_wakeup &&
					!udev->do_remote_wakeup) {
				dev_dbg(&udev->dev, "remote wakeup needed "
						"for autosuspend\n");
				return -EOPNOTSUPP;
			}
A
Alan Stern 已提交
952 953 954 955 956 957 958 959 960 961 962 963

			/* Don't allow autosuspend if the device will need
			 * a reset-resume and any of its interface drivers
			 * doesn't include support.
			 */
			if (udev->quirks & USB_QUIRK_RESET_RESUME) {
				struct usb_driver *driver;

				driver = to_usb_driver(intf->dev.driver);
				if (!driver->reset_resume)
					return -EOPNOTSUPP;
			}
A
Alan Stern 已提交
964 965
		}
	}
966 967

	/* If everything is okay but the device hasn't been idle for long
968 969 970
	 * enough, queue a delayed autosuspend request.  If the device
	 * _has_ been idle for long enough and the reschedule flag is set,
	 * likewise queue a delayed (1 second) autosuspend request.
971
	 */
972 973 974 975 976 977
	j = jiffies;
	if (time_before(j, suspend_time))
		reschedule = 1;
	else
		suspend_time = j + HZ;
	if (reschedule) {
978
		if (!timer_pending(&udev->autosuspend.timer)) {
979
			queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
980 981
				round_jiffies_relative(suspend_time - j));
		}
982 983
		return -EAGAIN;
	}
A
Alan Stern 已提交
984 985 986
	return 0;
}

987 988
#else

989
static inline int autosuspend_check(struct usb_device *udev, int reschedule)
A
Alan Stern 已提交
990 991 992
{
	return 0;
}
993

994
#endif	/* CONFIG_USB_SUSPEND */
995

996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031
/**
 * usb_suspend_both - suspend a USB device and its interfaces
 * @udev: the usb_device to suspend
 * @msg: Power Management message describing this state transition
 *
 * This is the central routine for suspending USB devices.  It calls the
 * suspend methods for all the interface drivers in @udev and then calls
 * the suspend method for @udev itself.  If an error occurs at any stage,
 * all the interfaces which were suspended are resumed so that they remain
 * in the same state as the device.
 *
 * If an autosuspend is in progress (@udev->auto_pm is set), the routine
 * checks first to make sure that neither the device itself or any of its
 * active interfaces is in use (pm_usage_cnt is greater than 0).  If they
 * are, the autosuspend fails.
 *
 * If the suspend succeeds, the routine recursively queues an autosuspend
 * request for @udev's parent device, thereby propagating the change up
 * the device tree.  If all of the parent's children are now suspended,
 * the parent will autosuspend in turn.
 *
 * The suspend method calls are subject to mutual exclusion under control
 * of @udev's pm_mutex.  Many of these calls are also under the protection
 * of @udev's device lock (including all requests originating outside the
 * USB subsystem), but autosuspend requests generated by a child device or
 * interface driver may not be.  Usbcore will insure that the method calls
 * do not arrive during bind, unbind, or reset operations.  However, drivers
 * must be prepared to handle suspend calls arriving at unpredictable times.
 * The only way to block such calls is to do an autoresume (preventing
 * autosuspends) while holding @udev's device lock (preventing outside
 * suspends).
 *
 * The caller must hold @udev->pm_mutex.
 *
 * This routine can run only in process context.
 */
A
Alan Stern 已提交
1032
static int usb_suspend_both(struct usb_device *udev, pm_message_t msg)
1033 1034 1035 1036
{
	int			status = 0;
	int			i = 0;
	struct usb_interface	*intf;
1037 1038
	struct usb_device	*parent = udev->parent;

1039 1040 1041
	if (udev->state == USB_STATE_NOTATTACHED ||
			udev->state == USB_STATE_SUSPENDED)
		goto done;
1042

1043 1044 1045
	udev->do_remote_wakeup = device_may_wakeup(&udev->dev);

	if (udev->auto_pm) {
1046
		status = autosuspend_check(udev, 0);
A
Alan Stern 已提交
1047
		if (status < 0)
1048
			goto done;
1049 1050 1051
	}

	/* Suspend all the interfaces and then udev itself */
1052 1053 1054
	if (udev->actconfig) {
		for (; i < udev->actconfig->desc.bNumInterfaces; i++) {
			intf = udev->actconfig->interface[i];
1055
			status = usb_suspend_interface(intf, msg);
1056 1057 1058 1059
			if (status != 0)
				break;
		}
	}
1060
	if (status == 0)
1061
		status = usb_suspend_device(udev, msg);
1062 1063 1064 1065 1066

	/* If the suspend failed, resume interfaces that did get suspended */
	if (status != 0) {
		while (--i >= 0) {
			intf = udev->actconfig->interface[i];
A
Alan Stern 已提交
1067
			usb_resume_interface(intf, 0);
1068
		}
1069

A
Alan Stern 已提交
1070 1071
		/* Try another autosuspend when the interfaces aren't busy */
		if (udev->auto_pm)
1072
			autosuspend_check(udev, status == -EBUSY);
A
Alan Stern 已提交
1073

1074 1075 1076
	/* If the suspend succeeded then prevent any more URB submissions,
	 * flush any outstanding URBs, and propagate the suspend up the tree.
	 */
A
Alan Stern 已提交
1077 1078
	} else {
		cancel_delayed_work(&udev->autosuspend);
1079 1080 1081 1082 1083
		udev->can_submit = 0;
		for (i = 0; i < 16; ++i) {
			usb_hcd_flush_endpoint(udev, udev->ep_out[i]);
			usb_hcd_flush_endpoint(udev, udev->ep_in[i]);
		}
1084 1085 1086 1087 1088 1089

		/* If this is just a FREEZE or a PRETHAW, udev might
		 * not really be suspended.  Only true suspends get
		 * propagated up the device tree.
		 */
		if (parent && udev->state == USB_STATE_SUSPENDED)
A
Alan Stern 已提交
1090 1091
			usb_autosuspend_device(parent);
	}
1092

1093
 done:
1094
	dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
1095 1096 1097
	return status;
}

1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125
/**
 * usb_resume_both - resume a USB device and its interfaces
 * @udev: the usb_device to resume
 *
 * This is the central routine for resuming USB devices.  It calls the
 * the resume method for @udev and then calls the resume methods for all
 * the interface drivers in @udev.
 *
 * Before starting the resume, the routine calls itself recursively for
 * the parent device of @udev, thereby propagating the change up the device
 * tree and assuring that @udev will be able to resume.  If the parent is
 * unable to resume successfully, the routine fails.
 *
 * The resume method calls are subject to mutual exclusion under control
 * of @udev's pm_mutex.  Many of these calls are also under the protection
 * of @udev's device lock (including all requests originating outside the
 * USB subsystem), but autoresume requests generated by a child device or
 * interface driver may not be.  Usbcore will insure that the method calls
 * do not arrive during bind, unbind, or reset operations.  However, drivers
 * must be prepared to handle resume calls arriving at unpredictable times.
 * The only way to block such calls is to do an autoresume (preventing
 * other autoresumes) while holding @udev's device lock (preventing outside
 * resumes).
 *
 * The caller must hold @udev->pm_mutex.
 *
 * This routine can run only in process context.
 */
A
Alan Stern 已提交
1126
static int usb_resume_both(struct usb_device *udev)
1127
{
1128
	int			status = 0;
1129 1130
	int			i;
	struct usb_interface	*intf;
1131 1132 1133
	struct usb_device	*parent = udev->parent;

	cancel_delayed_work(&udev->autosuspend);
1134 1135 1136 1137
	if (udev->state == USB_STATE_NOTATTACHED) {
		status = -ENODEV;
		goto done;
	}
1138
	udev->can_submit = 1;
1139

1140 1141
	/* Propagate the resume up the tree, if necessary */
	if (udev->state == USB_STATE_SUSPENDED) {
1142 1143 1144 1145
		if (udev->auto_pm && udev->autoresume_disabled) {
			status = -EPERM;
			goto done;
		}
1146
		if (parent) {
1147
			status = usb_autoresume_device(parent);
1148 1149
			if (status == 0) {
				status = usb_resume_device(udev);
A
Alan Stern 已提交
1150 1151
				if (status || udev->state ==
						USB_STATE_NOTATTACHED) {
1152
					usb_autosuspend_device(parent);
1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166

					/* It's possible usb_resume_device()
					 * failed after the port was
					 * unsuspended, causing udev to be
					 * logically disconnected.  We don't
					 * want usb_disconnect() to autosuspend
					 * the parent again, so tell it that
					 * udev disconnected while still
					 * suspended. */
					if (udev->state ==
							USB_STATE_NOTATTACHED)
						udev->discon_suspended = 1;
				}
			}
1167 1168 1169 1170 1171
		} else {

			/* We can't progagate beyond the USB subsystem,
			 * so if a root hub's controller is suspended
			 * then we're stuck. */
1172
			status = usb_resume_device(udev);
1173
		}
A
Alan Stern 已提交
1174
	} else if (udev->reset_resume)
1175
		status = usb_resume_device(udev);
1176

1177 1178 1179
	if (status == 0 && udev->actconfig) {
		for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
			intf = udev->actconfig->interface[i];
A
Alan Stern 已提交
1180
			usb_resume_interface(intf, udev->reset_resume);
1181 1182
		}
	}
1183

1184
 done:
1185
	dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
A
Alan Stern 已提交
1186 1187
	if (!status)
		udev->reset_resume = 0;
1188 1189 1190 1191 1192
	return status;
}

#ifdef CONFIG_USB_SUSPEND

1193 1194 1195 1196 1197 1198 1199 1200
/* Internal routine to adjust a device's usage counter and change
 * its autosuspend state.
 */
static int usb_autopm_do_device(struct usb_device *udev, int inc_usage_cnt)
{
	int	status = 0;

	usb_pm_lock(udev);
1201
	udev->auto_pm = 1;
1202 1203
	udev->pm_usage_cnt += inc_usage_cnt;
	WARN_ON(udev->pm_usage_cnt < 0);
1204 1205
	if (inc_usage_cnt)
		udev->last_busy = jiffies;
1206
	if (inc_usage_cnt >= 0 && udev->pm_usage_cnt > 0) {
1207 1208
		if (udev->state == USB_STATE_SUSPENDED)
			status = usb_resume_both(udev);
1209 1210
		if (status != 0)
			udev->pm_usage_cnt -= inc_usage_cnt;
1211 1212 1213 1214 1215
		else if (inc_usage_cnt)
			udev->last_busy = jiffies;
	} else if (inc_usage_cnt <= 0 && udev->pm_usage_cnt <= 0) {
		status = usb_suspend_both(udev, PMSG_SUSPEND);
	}
1216 1217 1218 1219
	usb_pm_unlock(udev);
	return status;
}

1220 1221 1222 1223 1224 1225 1226 1227 1228
/* usb_autosuspend_work - callback routine to autosuspend a USB device */
void usb_autosuspend_work(struct work_struct *work)
{
	struct usb_device *udev =
		container_of(work, struct usb_device, autosuspend.work);

	usb_autopm_do_device(udev, 0);
}

1229 1230
/**
 * usb_autosuspend_device - delayed autosuspend of a USB device and its interfaces
1231
 * @udev: the usb_device to autosuspend
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 *
 * This routine should be called when a core subsystem is finished using
 * @udev and wants to allow it to autosuspend.  Examples would be when
 * @udev's device file in usbfs is closed or after a configuration change.
 *
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 * @udev's usage counter is decremented.  If it or any of the usage counters
 * for an active interface is greater than 0, no autosuspend request will be
 * queued.  (If an interface driver does not support autosuspend then its
 * usage counter is permanently positive.)  Furthermore, if an interface
 * driver requires remote-wakeup capability during autosuspend but remote
 * wakeup is disabled, the autosuspend will fail.
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 *
 * Often the caller will hold @udev's device lock, but this is not
 * necessary.
 *
 * This routine can run only in process context.
 */
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void usb_autosuspend_device(struct usb_device *udev)
1250
{
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	int	status;

	status = usb_autopm_do_device(udev, -1);
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	dev_vdbg(&udev->dev, "%s: cnt %d\n",
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			__func__, udev->pm_usage_cnt);
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}

/**
 * usb_try_autosuspend_device - attempt an autosuspend of a USB device and its interfaces
 * @udev: the usb_device to autosuspend
 *
 * This routine should be called when a core subsystem thinks @udev may
 * be ready to autosuspend.
 *
 * @udev's usage counter left unchanged.  If it or any of the usage counters
 * for an active interface is greater than 0, or autosuspend is not allowed
 * for any other reason, no autosuspend request will be queued.
 *
 * This routine can run only in process context.
 */
void usb_try_autosuspend_device(struct usb_device *udev)
{
	usb_autopm_do_device(udev, 0);
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	dev_vdbg(&udev->dev, "%s: cnt %d\n",
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			__func__, udev->pm_usage_cnt);
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}

/**
 * usb_autoresume_device - immediately autoresume a USB device and its interfaces
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 * @udev: the usb_device to autoresume
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 *
 * This routine should be called when a core subsystem wants to use @udev
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 * and needs to guarantee that it is not suspended.  No autosuspend will
 * occur until usb_autosuspend_device is called.  (Note that this will not
 * prevent suspend events originating in the PM core.)  Examples would be
 * when @udev's device file in usbfs is opened or when a remote-wakeup
 * request is received.
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 *
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 * @udev's usage counter is incremented to prevent subsequent autosuspends.
 * However if the autoresume fails then the usage counter is re-decremented.
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 *
 * Often the caller will hold @udev's device lock, but this is not
 * necessary (and attempting it might cause deadlock).
 *
 * This routine can run only in process context.
 */
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int usb_autoresume_device(struct usb_device *udev)
1298 1299 1300
{
	int	status;

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	status = usb_autopm_do_device(udev, 1);
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	dev_vdbg(&udev->dev, "%s: status %d cnt %d\n",
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			__func__, status, udev->pm_usage_cnt);
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	return status;
}

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/* Internal routine to adjust an interface's usage counter and change
 * its device's autosuspend state.
 */
static int usb_autopm_do_interface(struct usb_interface *intf,
		int inc_usage_cnt)
{
	struct usb_device	*udev = interface_to_usbdev(intf);
	int			status = 0;

	usb_pm_lock(udev);
	if (intf->condition == USB_INTERFACE_UNBOUND)
		status = -ENODEV;
	else {
1320
		udev->auto_pm = 1;
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		intf->pm_usage_cnt += inc_usage_cnt;
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		udev->last_busy = jiffies;
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		if (inc_usage_cnt >= 0 && intf->pm_usage_cnt > 0) {
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			if (udev->state == USB_STATE_SUSPENDED)
				status = usb_resume_both(udev);
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			if (status != 0)
				intf->pm_usage_cnt -= inc_usage_cnt;
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			else
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				udev->last_busy = jiffies;
		} else if (inc_usage_cnt <= 0 && intf->pm_usage_cnt <= 0) {
			status = usb_suspend_both(udev, PMSG_SUSPEND);
		}
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	}
	usb_pm_unlock(udev);
	return status;
}

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/**
 * usb_autopm_put_interface - decrement a USB interface's PM-usage counter
1340
 * @intf: the usb_interface whose counter should be decremented
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 *
 * This routine should be called by an interface driver when it is
 * finished using @intf and wants to allow it to autosuspend.  A typical
 * example would be a character-device driver when its device file is
 * closed.
 *
 * The routine decrements @intf's usage counter.  When the counter reaches
 * 0, a delayed autosuspend request for @intf's device is queued.  When
 * the delay expires, if @intf->pm_usage_cnt is still <= 0 along with all
 * the other usage counters for the sibling interfaces and @intf's
 * usb_device, the device and all its interfaces will be autosuspended.
 *
 * Note that @intf->pm_usage_cnt is owned by the interface driver.  The
 * core will not change its value other than the increment and decrement
 * in usb_autopm_get_interface and usb_autopm_put_interface.  The driver
 * may use this simple counter-oriented discipline or may set the value
 * any way it likes.
 *
 * If the driver has set @intf->needs_remote_wakeup then autosuspend will
 * take place only if the device's remote-wakeup facility is enabled.
 *
 * Suspend method calls queued by this routine can arrive at any time
 * while @intf is resumed and its usage counter is equal to 0.  They are
 * not protected by the usb_device's lock but only by its pm_mutex.
 * Drivers must provide their own synchronization.
 *
 * This routine can run only in process context.
 */
void usb_autopm_put_interface(struct usb_interface *intf)
{
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	int	status;
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	status = usb_autopm_do_interface(intf, -1);
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	dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
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			__func__, status, intf->pm_usage_cnt);
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}
EXPORT_SYMBOL_GPL(usb_autopm_put_interface);

/**
 * usb_autopm_get_interface - increment a USB interface's PM-usage counter
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 * @intf: the usb_interface whose counter should be incremented
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 *
 * This routine should be called by an interface driver when it wants to
 * use @intf and needs to guarantee that it is not suspended.  In addition,
 * the routine prevents @intf from being autosuspended subsequently.  (Note
 * that this will not prevent suspend events originating in the PM core.)
 * This prevention will persist until usb_autopm_put_interface() is called
 * or @intf is unbound.  A typical example would be a character-device
 * driver when its device file is opened.
 *
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 *
 * The routine increments @intf's usage counter.  (However if the
 * autoresume fails then the counter is re-decremented.)  So long as the
 * counter is greater than 0, autosuspend will not be allowed for @intf
 * or its usb_device.  When the driver is finished using @intf it should
 * call usb_autopm_put_interface() to decrement the usage counter and
 * queue a delayed autosuspend request (if the counter is <= 0).
 *
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 *
 * Note that @intf->pm_usage_cnt is owned by the interface driver.  The
 * core will not change its value other than the increment and decrement
 * in usb_autopm_get_interface and usb_autopm_put_interface.  The driver
 * may use this simple counter-oriented discipline or may set the value
 * any way it likes.
 *
 * Resume method calls generated by this routine can arrive at any time
 * while @intf is suspended.  They are not protected by the usb_device's
 * lock but only by its pm_mutex.  Drivers must provide their own
 * synchronization.
 *
 * This routine can run only in process context.
 */
int usb_autopm_get_interface(struct usb_interface *intf)
{
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	int	status;
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	status = usb_autopm_do_interface(intf, 1);
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	dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
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			__func__, status, intf->pm_usage_cnt);
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	return status;
}
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EXPORT_SYMBOL_GPL(usb_autopm_get_interface);

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/**
 * usb_autopm_set_interface - set a USB interface's autosuspend state
 * @intf: the usb_interface whose state should be set
 *
 * This routine sets the autosuspend state of @intf's device according
 * to @intf's usage counter, which the caller must have set previously.
 * If the counter is <= 0, the device is autosuspended (if it isn't
 * already suspended and if nothing else prevents the autosuspend).  If
 * the counter is > 0, the device is autoresumed (if it isn't already
 * awake).
 */
int usb_autopm_set_interface(struct usb_interface *intf)
{
	int	status;

	status = usb_autopm_do_interface(intf, 0);
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	dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
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			__func__, status, intf->pm_usage_cnt);
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	return status;
}
EXPORT_SYMBOL_GPL(usb_autopm_set_interface);

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#else

void usb_autosuspend_work(struct work_struct *work)
{}

1451
#endif /* CONFIG_USB_SUSPEND */
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/**
 * usb_external_suspend_device - external suspend of a USB device and its interfaces
 * @udev: the usb_device to suspend
 * @msg: Power Management message describing this state transition
 *
 * This routine handles external suspend requests: ones not generated
 * internally by a USB driver (autosuspend) but rather coming from the user
 * (via sysfs) or the PM core (system sleep).  The suspend will be carried
 * out regardless of @udev's usage counter or those of its interfaces,
 * and regardless of whether or not remote wakeup is enabled.  Of course,
 * interface drivers still have the option of failing the suspend (if
 * there are unsuspended children, for example).
 *
 * The caller must hold @udev's device lock.
 */
int usb_external_suspend_device(struct usb_device *udev, pm_message_t msg)
1469 1470 1471
{
	int	status;

1472 1473 1474 1475
	usb_pm_lock(udev);
	udev->auto_pm = 0;
	status = usb_suspend_both(udev, msg);
	usb_pm_unlock(udev);
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	return status;
}

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/**
 * usb_external_resume_device - external resume of a USB device and its interfaces
 * @udev: the usb_device to resume
 *
 * This routine handles external resume requests: ones not generated
 * internally by a USB driver (autoresume) but rather coming from the user
 * (via sysfs), the PM core (system resume), or the device itself (remote
 * wakeup).  @udev's usage counter is unaffected.
 *
 * The caller must hold @udev's device lock.
 */
int usb_external_resume_device(struct usb_device *udev)
1491 1492 1493
{
	int	status;

1494 1495 1496
	usb_pm_lock(udev);
	udev->auto_pm = 0;
	status = usb_resume_both(udev);
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	udev->last_busy = jiffies;
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	usb_pm_unlock(udev);
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	/* Now that the device is awake, we can start trying to autosuspend
	 * it again. */
	if (status == 0)
		usb_try_autosuspend_device(udev);
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	return status;
}

1507 1508
static int usb_suspend(struct device *dev, pm_message_t message)
{
1509 1510
	struct usb_device	*udev;

1511 1512
	if (!is_usb_device(dev))	/* Ignore PM for interfaces */
		return 0;
1513 1514 1515
	udev = to_usb_device(dev);

	/* If udev is already suspended, we can skip this suspend and
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	 * we should also skip the upcoming system resume.  High-speed
	 * root hubs are an exception; they need to resume whenever the
	 * system wakes up in order for USB-PERSIST port handover to work
	 * properly.
	 */
1521
	if (udev->state == USB_STATE_SUSPENDED) {
1522 1523
		if (udev->parent || udev->speed != USB_SPEED_HIGH)
			udev->skip_sys_resume = 1;
1524 1525 1526 1527 1528
		return 0;
	}

	udev->skip_sys_resume = 0;
	return usb_external_suspend_device(udev, message);
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}

static int usb_resume(struct device *dev)
{
1533 1534
	struct usb_device	*udev;

1535 1536
	if (!is_usb_device(dev))	/* Ignore PM for interfaces */
		return 0;
1537
	udev = to_usb_device(dev);
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	/* If udev->skip_sys_resume is set then udev was already suspended
	 * when the system suspend started, so we don't want to resume
	 * udev during this system wakeup.  However a reset-resume counts
	 * as a wakeup event, so allow a reset-resume to occur if remote
	 * wakeup is enabled. */
	if (udev->skip_sys_resume) {
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		if (!(udev->reset_resume && udev->do_remote_wakeup))
1546
			return -EHOSTUNREACH;
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	}
1548
	return usb_external_resume_device(udev);
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}

#else

#define usb_suspend	NULL
#define usb_resume	NULL

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#endif /* CONFIG_PM */

struct bus_type usb_bus_type = {
	.name =		"usb",
	.match =	usb_device_match,
	.uevent =	usb_uevent,
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	.suspend =	usb_suspend,
	.resume =	usb_resume,
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};