text: // SPDX-License-Identifier: GPL-2.0
  /*
   * drivers/usb/core/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
   *
   * Released under the GPLv2 only.
   *
   * NOTE! This is not actually a driver at all, rather this is
   * just a collection of helper routines that implement the
   * matching, probing, releasing, suspending and resuming for
   * real drivers.
   *
   */
  
  #include <linux/device.h>
  #include <linux/slab.h>
  #include <linux/export.h>
  #include <linux/usb.h>
  #include <linux/usb/quirks.h>
  #include <linux/usb/hcd.h>
  
  #include "usb.h"
  
  
  /*
   * Adds a new dynamic USBdevice ID to this driver,
   * and cause the driver to probe for all devices again.
   */
  ssize_t usb_store_new_id(struct usb_dynids *dynids,
  			 const struct usb_device_id *id_table,
  			 struct device_driver *driver,
  			 const char *buf, size_t count)
  {
  	struct usb_dynid *dynid;
  	u32 idVendor = 0;
  	u32 idProduct = 0;
  	unsigned int bInterfaceClass = 0;
  	u32 refVendor, refProduct;
  	int fields = 0;
  	int retval = 0;
  
  	fields = sscanf(buf, "%x %x %x %x %x", &idVendor, &idProduct,
  			&bInterfaceClass, &refVendor, &refProduct);
  	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;
  	if (fields > 2 && bInterfaceClass) {
  		if (bInterfaceClass > 255) {
  			retval = -EINVAL;
  			goto fail;
  		}
  
  		dynid->id.bInterfaceClass = (u8)bInterfaceClass;
  		dynid->id.match_flags |= USB_DEVICE_ID_MATCH_INT_CLASS;
  	}
  
  	if (fields > 4) {
  		const struct usb_device_id *id = id_table;
  
  		if (!id) {
  			retval = -ENODEV;
  			goto fail;
  		}
  
  		for (; id->match_flags; id++)
  			if (id->idVendor == refVendor && id->idProduct == refProduct)
  				break;
  
  		if (id->match_flags) {
  			dynid->id.driver_info = id->driver_info;
  		} else {
  			retval = -ENODEV;
  			goto fail;
  		}
  	}
  
  	spin_lock(&dynids->lock);
  	list_add_tail(&dynid->node, &dynids->list);
  	spin_unlock(&dynids->lock);
  
  	retval = driver_attach(driver);
  
  	if (retval)
  		return retval;
  	return count;
  
  fail:
  	kfree(dynid);
  	return retval;
  }
  EXPORT_SYMBOL_GPL(usb_store_new_id);
  
  ssize_t usb_show_dynids(struct usb_dynids *dynids, char *buf)
  {
  	struct usb_dynid *dynid;
  	size_t count = 0;
  
  	list_for_each_entry(dynid, &dynids->list, node)
  		if (dynid->id.bInterfaceClass != 0)
  			count += scnprintf(&buf[count], PAGE_SIZE - count, "%04x %04x %02x\n",
  					   dynid->id.idVendor, dynid->id.idProduct,
  					   dynid->id.bInterfaceClass);
  		else
  			count += scnprintf(&buf[count], PAGE_SIZE - count, "%04x %04x\n",
  					   dynid->id.idVendor, dynid->id.idProduct);
  	return count;
  }
  EXPORT_SYMBOL_GPL(usb_show_dynids);
  
  static ssize_t new_id_show(struct device_driver *driver, char *buf)
  {
  	struct usb_driver *usb_drv = to_usb_driver(driver);
  
  	return usb_show_dynids(&usb_drv->dynids, buf);
  }
  
  static ssize_t new_id_store(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, usb_drv->id_table, driver, buf, count);
  }
  static DRIVER_ATTR_RW(new_id);
  
  /*
   * Remove a USB device ID from this driver
   */
  static ssize_t remove_id_store(struct device_driver *driver, const char *buf,
  			       size_t count)
  {
  	struct usb_dynid *dynid, *n;
  	struct usb_driver *usb_driver = to_usb_driver(driver);
  	u32 idVendor;
  	u32 idProduct;
  	int fields;
  
  	fields = sscanf(buf, "%x %x", &idVendor, &idProduct);
  	if (fields < 2)
  		return -EINVAL;
  
  	spin_lock(&usb_driver->dynids.lock);
  	list_for_each_entry_safe(dynid, n, &usb_driver->dynids.list, node) {
  		struct usb_device_id *id = &dynid->id;
  
  		if ((id->idVendor == idVendor) &&
  		    (id->idProduct == idProduct)) {
  			list_del(&dynid->node);
  			kfree(dynid);
  			break;
  		}
  	}
  	spin_unlock(&usb_driver->dynids.lock);
  	return count;
  }
  
  static ssize_t remove_id_show(struct device_driver *driver, char *buf)
  {
  	return new_id_show(driver, buf);
  }
  static DRIVER_ATTR_RW(remove_id);
  
  static int usb_create_newid_files(struct usb_driver *usb_drv)
  {
  	int error = 0;
  
  	if (usb_drv->no_dynamic_id)
  		goto exit;
  
  	if (usb_drv->probe != NULL) {
  		error = driver_create_file(&usb_drv->drvwrap.driver,
  					   &driver_attr_new_id);
  		if (error == 0) {
  			error = driver_create_file(&usb_drv->drvwrap.driver,
  					&driver_attr_remove_id);
  			if (error)
  				driver_remove_file(&usb_drv->drvwrap.driver,
  						&driver_attr_new_id);
  		}
  	}
  exit:
  	return error;
  }
  
  static void usb_remove_newid_files(struct usb_driver *usb_drv)
  {
  	if (usb_drv->no_dynamic_id)
  		return;
  
  	if (usb_drv->probe != NULL) {
  		driver_remove_file(&usb_drv->drvwrap.driver,
  				&driver_attr_remove_id);
  		driver_remove_file(&usb_drv->drvwrap.driver,
  				   &driver_attr_new_id);
  	}
  }
  
  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);
  }
  
  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;
  }
  
  
  /* 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 = to_usb_device(dev);
  	int error = 0;
  
  	dev_dbg(dev, "%s\n", __func__);
  
  	/* TODO: Add real matching code */
  
  	/* The device should always appear to be in use
  	 * unless the driver supports autosuspend.
  	 */
  	if (!udriver->supports_autosuspend)
  		error = usb_autoresume_device(udev);
  	if (error)
  		return error;
  
  	if (udriver->generic_subclass)
  		error = usb_generic_driver_probe(udev);
  	if (error)
  		return error;
  
  	/* Probe the USB device with the driver in hand, but only
  	 * defer to a generic driver in case the current USB
  	 * device driver has an id_table or a match function; i.e.,
  	 * when the device driver was explicitly matched against
  	 * a device.
  	 *
  	 * If the device driver does not have either of these,
  	 * then we assume that it can bind to any device and is
  	 * not truly a more specialized/non-generic driver, so a
  	 * return value of -ENODEV should not force the device
  	 * to be handled by the generic USB driver, as there
  	 * can still be another, more specialized, device driver.
  	 *
  	 * This accommodates the usbip driver.
  	 *
  	 * TODO: What if, in the future, there are multiple
  	 * specialized USB device drivers for a particular device?
  	 * In such cases, there is a need to try all matching
  	 * specialised device drivers prior to setting the
  	 * use_generic_driver bit.
  	 */
  	error = udriver->probe(udev);
  	if (error == -ENODEV && udriver != &usb_generic_driver &&
  	    (udriver->id_table || udriver->match)) {
  		udev->use_generic_driver = 1;
  		return -EPROBE_DEFER;
  	}
  	return error;
  }
  
  /* called from driver core with dev locked */
  static int usb_unbind_device(struct device *dev)
  {
  	struct usb_device *udev = to_usb_device(dev);
  	struct usb_device_driver *udriver = to_usb_device_driver(dev->driver);
  
  	if (udriver->disconnect)
  		udriver->disconnect(udev);
  	if (udriver->generic_subclass)
  		usb_generic_driver_disconnect(udev);
  	if (!udriver->supports_autosuspend)
  		usb_autosuspend_device(udev);
  	return 0;
  }
  
  /* called from driver core with dev locked */
  static int usb_probe_interface(struct device *dev)
  {
  	struct usb_driver *driver = to_usb_driver(dev->driver);
  	struct usb_interface *intf = to_usb_interface(dev);
  	struct usb_device *udev = interface_to_usbdev(intf);
  	const struct usb_device_id *id;
  	int error = -ENODEV;
  	int lpm_disable_error = -ENODEV;
  
  	dev_dbg(dev, "%s\n", __func__);
  
  	intf->needs_binding = 0;
  
  	if (usb_device_is_owned(udev))
  		return error;
  
  	if (udev->authorized == 0) {
  		dev_err(&intf->dev, "Device is not authorized for usage\n");
  		return error;
  	} else if (intf->authorized == 0) {
  		dev_err(&intf->dev, "Interface %d is not authorized for usage\n",
  				intf->altsetting->desc.bInterfaceNumber);
  		return error;
  	}
  
  	id = usb_match_dynamic_id(intf, driver);
  	if (!id)
  		id = usb_match_id(intf, driver->id_table);
  	if (!id)
  		return error;
  
  	dev_dbg(dev, "%s - got id\n", __func__);
  
  	error = usb_autoresume_device(udev);
  	if (error)
  		return error;
  
  	intf->condition = USB_INTERFACE_BINDING;
  
  	/* Probed interfaces are initially active.  They are
  	 * runtime-PM-enabled only if the driver has autosuspend support.
  	 * They are sensitive to their children's power states.
  	 */
  	pm_runtime_set_active(dev);
  	pm_suspend_ignore_children(dev, false);
  	if (driver->supports_autosuspend)
  		pm_runtime_enable(dev);
  
  	/* If the new driver doesn't allow hub-initiated LPM, and we can't
  	 * disable hub-initiated LPM, then fail the probe.
  	 *
  	 * Otherwise, leaving LPM enabled should be harmless, because the
  	 * endpoint intervals should remain the same, and the U1/U2 timeouts
  	 * should remain the same.
  	 *
  	 * If we need to install alt setting 0 before probe, or another alt
  	 * setting during probe, that should also be fine.  usb_set_interface()
  	 * will attempt to disable LPM, and fail if it can't disable it.
  	 */
  	if (driver->disable_hub_initiated_lpm) {
  		lpm_disable_error = usb_unlocked_disable_lpm(udev);
  		if (lpm_disable_error) {
  			dev_err(&intf->dev, "%s Failed to disable LPM for driver %s\n",
  				__func__, driver->name);
  			error = lpm_disable_error;
  			goto err;
  		}
  	}
  
  	/* Carry out a deferred switch to altsetting 0 */
  	if (intf->needs_altsetting0) {
  		error = usb_set_interface(udev, intf->altsetting[0].
  				desc.bInterfaceNumber, 0);
  		if (error < 0)
  			goto err;
  		intf->needs_altsetting0 = 0;
  	}
  
  	error = driver->probe(intf, id);
  	if (error)
  		goto err;
  
  	intf->condition = USB_INTERFACE_BOUND;
  
  	/* If the LPM disable succeeded, balance the ref counts. */
  	if (!lpm_disable_error)
  		usb_unlocked_enable_lpm(udev);
  
  	usb_autosuspend_device(udev);
  	return error;
  
   err:
  	usb_set_intfdata(intf, NULL);
  	intf->needs_remote_wakeup = 0;
  	intf->condition = USB_INTERFACE_UNBOUND;
  
  	/* If the LPM disable succeeded, balance the ref counts. */
  	if (!lpm_disable_error)
  		usb_unlocked_enable_lpm(udev);
  
  	/* Unbound interfaces are always runtime-PM-disabled and -suspended */
  	if (driver->supports_autosuspend)
  		pm_runtime_disable(dev);
  	pm_runtime_set_suspended(dev);
  
  	usb_autosuspend_device(udev);
  	return error;
  }
  
  /* called from driver core with dev locked */
  static int usb_unbind_interface(struct device *dev)
  {
  	struct usb_driver *driver = to_usb_driver(dev->driver);
  	struct usb_interface *intf = to_usb_interface(dev);
  	struct usb_host_endpoint *ep, **eps = NULL;
  	struct usb_device *udev;
  	int i, j, error, r;
  	int lpm_disable_error = -ENODEV;
  
  	intf->condition = USB_INTERFACE_UNBINDING;
  
  	/* Autoresume for set_interface call below */
  	udev = interface_to_usbdev(intf);
  	error = usb_autoresume_device(udev);
  
  	/* If hub-initiated LPM policy may change, attempt to disable LPM until
  	 * the driver is unbound.  If LPM isn't disabled, that's fine because it
  	 * wouldn't be enabled unless all the bound interfaces supported
  	 * hub-initiated LPM.
  	 */
  	if (driver->disable_hub_initiated_lpm)
  		lpm_disable_error = usb_unlocked_disable_lpm(udev);
  
  	/*
  	 * Terminate all URBs for this interface unless the driver
  	 * supports "soft" unbinding and the device is still present.
  	 */
  	if (!driver->soft_unbind || udev->state == USB_STATE_NOTATTACHED)
  		usb_disable_interface(udev, intf, false);
  
  	driver->disconnect(intf);
  
  	/* Free streams */
  	for (i = 0, j = 0; i < intf->cur_altsetting->desc.bNumEndpoints; i++) {
  		ep = &intf->cur_altsetting->endpoint[i];
  		if (ep->streams == 0)
  			continue;
  		if (j == 0) {
  			eps = kmalloc_array(USB_MAXENDPOINTS, sizeof(void *),
  				      GFP_KERNEL);
  			if (!eps)
  				break;
  		}
  		eps[j++] = ep;
  	}
  	if (j) {
  		usb_free_streams(intf, eps, j, GFP_KERNEL);
  		kfree(eps);
  	}
  
  	/* Reset other interface state.
  	 * We cannot do a Set-Interface if the device is suspended or
  	 * if it is prepared for a system sleep (since installing a new
  	 * altsetting means creating new endpoint device entries).
  	 * When either of these happens, defer the Set-Interface.
  	 */
  	if (intf->cur_altsetting->desc.bAlternateSetting == 0) {
  		/* Already in altsetting 0 so skip Set-Interface.
  		 * Just re-enable it without affecting the endpoint toggles.
  		 */
  		usb_enable_interface(udev, intf, false);
  	} else if (!error && !intf->dev.power.is_prepared) {
  		r = usb_set_interface(udev, intf->altsetting[0].
  				desc.bInterfaceNumber, 0);
  		if (r < 0)
  			intf->needs_altsetting0 = 1;
  	} else {
  		intf->needs_altsetting0 = 1;
  	}
  	usb_set_intfdata(intf, NULL);
  
  	intf->condition = USB_INTERFACE_UNBOUND;
  	intf->needs_remote_wakeup = 0;
  
  	/* Attempt to re-enable USB3 LPM, if the disable succeeded. */
  	if (!lpm_disable_error)
  		usb_unlocked_enable_lpm(udev);
  
  	/* Unbound interfaces are always runtime-PM-disabled and -suspended */
  	if (driver->supports_autosuspend)
  		pm_runtime_disable(dev);
  	pm_runtime_set_suspended(dev);
  
  	if (!error)
  		usb_autosuspend_device(udev);
  
  	return 0;
  }
  
  /**
   * 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
   * @data: 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.
   *
   * 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.
   *
   * Return: 0 on success.
   */
  int usb_driver_claim_interface(struct usb_driver *driver,
  				struct usb_interface *iface, void *data)
  {
  	struct device *dev;
  	int retval = 0;
  
  	if (!iface)
  		return -ENODEV;
  
  	dev = &iface->dev;
  	if (dev->driver)
  		return -EBUSY;
  
  	/* reject claim if interface is not authorized */
  	if (!iface->authorized)
  		return -ENODEV;
  
  	dev->driver = &driver->drvwrap.driver;
  	usb_set_intfdata(iface, data);
  	iface->needs_binding = 0;
  
  	iface->condition = USB_INTERFACE_BOUND;
  
  	/* Claimed interfaces are initially inactive (suspended) and
  	 * runtime-PM-enabled, but only if the driver has autosuspend
  	 * support.  Otherwise they are marked active, to prevent the
  	 * device from being autosuspended, but left disabled.  In either
  	 * case they are sensitive to their children's power states.
  	 */
  	pm_suspend_ignore_children(dev, false);
  	if (driver->supports_autosuspend)
  		pm_runtime_enable(dev);
  	else
  		pm_runtime_set_active(dev);
  
  	/* if interface was already added, bind now; else let
  	 * the future device_add() bind it, bypassing probe()
  	 */
  	if (device_is_registered(dev))
  		retval = device_bind_driver(dev);
  
  	if (retval) {
  		dev->driver = NULL;
  		usb_set_intfdata(iface, NULL);
  		iface->needs_remote_wakeup = 0;
  		iface->condition = USB_INTERFACE_UNBOUND;
  
  		/*
  		 * Unbound interfaces are always runtime-PM-disabled
  		 * and runtime-PM-suspended
  		 */
  		if (driver->supports_autosuspend)
  			pm_runtime_disable(dev);
  		pm_runtime_set_suspended(dev);
  	}
  
  	return retval;
  }
  EXPORT_SYMBOL_GPL(usb_driver_claim_interface);
  
  /**
   * 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.
   * 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.
   */
  void usb_driver_release_interface(struct usb_driver *driver,
  					struct usb_interface *iface)
  {
  	struct device *dev = &iface->dev;
  
  	/* this should never happen, don't release something that's not ours */
  	if (!dev->driver || dev->driver != &driver->drvwrap.driver)
  		return;
  
  	/* don't release from within disconnect() */
  	if (iface->condition != USB_INTERFACE_BOUND)
  		return;
  	iface->condition = USB_INTERFACE_UNBINDING;
  
  	/* Release via the driver core only if the interface
  	 * has already been registered
  	 */
  	if (device_is_registered(dev)) {
  		device_release_driver(dev);
  	} else {
  		device_lock(dev);
  		usb_unbind_interface(dev);
  		dev->driver = NULL;
  		device_unlock(dev);
  	}
  }
  EXPORT_SYMBOL_GPL(usb_driver_release_interface);
  
  /* returns 0 if no match, 1 if match */
  int usb_match_device(struct usb_device *dev, const struct usb_device_id *id)
  {
  	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) &&
  	    (id->bDeviceSubClass != dev->descriptor.bDeviceSubClass))
  		return 0;
  
  	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_PROTOCOL) &&
  	    (id->bDeviceProtocol != dev->descriptor.bDeviceProtocol))
  		return 0;
  
  	return 1;
  }
  
  /* returns 0 if no match, 1 if match */
  int usb_match_one_id_intf(struct usb_device *dev,
  			  struct usb_host_interface *intf,
  			  const struct usb_device_id *id)
  {
  	/* The interface class, subclass, protocol and number 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 |
  				USB_DEVICE_ID_MATCH_INT_NUMBER)))
  		return 0;
  
  	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;
  
  	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_NUMBER) &&
  	    (id->bInterfaceNumber != intf->desc.bInterfaceNumber))
  		return 0;
  
  	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;
  
  	return usb_match_one_id_intf(dev, intf, id);
  }
  EXPORT_SYMBOL_GPL(usb_match_one_id);
  
  /**
   * 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.
   *
   * Return: The first matching usb_device_id, or %NULL.
   *
   * 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
   * 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.)
   *
   * 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. */
  	for (; id->idVendor || id->idProduct || id->bDeviceClass ||
  	       id->bInterfaceClass || id->driver_info; id++) {
  		if (usb_match_one_id(interface, id))
  			return id;
  	}
  
  	return NULL;
  }
  EXPORT_SYMBOL_GPL(usb_match_id);
  
  const struct usb_device_id *usb_device_match_id(struct usb_device *udev,
  				const struct usb_device_id *id)
  {
  	if (!id)
  		return NULL;
  
  	for (; id->idVendor || id->idProduct ; id++) {
  		if (usb_match_device(udev, id))
  			return id;
  	}
  
  	return NULL;
  }
  EXPORT_SYMBOL_GPL(usb_device_match_id);
  
  bool usb_driver_applicable(struct usb_device *udev,
  			   struct usb_device_driver *udrv)
  {
  	if (udrv->id_table && udrv->match)
  		return usb_device_match_id(udev, udrv->id_table) != NULL &&
  		       udrv->match(udev);
  
  	if (udrv->id_table)
  		return usb_device_match_id(udev, udrv->id_table) != NULL;
  
  	if (udrv->match)
  		return udrv->match(udev);
  
  	return false;
  }
  
  static int usb_device_match(struct device *dev, struct device_driver *drv)
  {
  	/* devices and interfaces are handled separately */
  	if (is_usb_device(dev)) {
  		struct usb_device *udev;
  		struct usb_device_driver *udrv;
  
  		/* interface drivers never match devices */
  		if (!is_usb_device_driver(drv))
  			return 0;
  
  		udev = to_usb_device(dev);
  		udrv = to_usb_device_driver(drv);
  
  		/* If the device driver under consideration does not have a
  		 * id_table or a match function, then let the driver's probe
  		 * function decide.
  		 */
  		if (!udrv->id_table && !udrv->match)
  			return 1;
  
  		return usb_driver_applicable(udev, udrv);
  
  	} else if (is_usb_interface(dev)) {
  		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;
  	}
  
  	return 0;
  }
  
  static int usb_uevent(struct device *dev, struct kobj_uevent_env *env)
  {
  	struct usb_device *usb_dev;
  
  	if (is_usb_device(dev)) {
  		usb_dev = to_usb_device(dev);
  	} else if (is_usb_interface(dev)) {
  		struct usb_interface *intf = to_usb_interface(dev);
  
  		usb_dev = interface_to_usbdev(intf);
  	} else {
  		return 0;
  	}
  
  	if (usb_dev->devnum < 0) {
  		/* driver is often null here; dev_dbg() would oops */
  		pr_debug("usb %s: already deleted?\n", dev_name(dev));
  		return -ENODEV;
  	}
  	if (!usb_dev->bus) {
  		pr_debug("usb %s: bus removed?\n", dev_name(dev));
  		return -ENODEV;
  	}
  
  	/* per-device configurations are common */
  	if (add_uevent_var(env, "PRODUCT=%x/%x/%x",
  			   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 */
  	if (add_uevent_var(env, "TYPE=%d/%d/%d",
  			   usb_dev->descriptor.bDeviceClass,
  			   usb_dev->descriptor.bDeviceSubClass,
  			   usb_dev->descriptor.bDeviceProtocol))
  		return -ENOMEM;
  
  	return 0;
  }
  
  static int __usb_bus_reprobe_drivers(struct device *dev, void *data)
  {
  	struct usb_device_driver *new_udriver = data;
  	struct usb_device *udev;
  	int ret;
  
  	/* Don't reprobe if current driver isn't usb_generic_driver */
  	if (dev->driver != &usb_generic_driver.drvwrap.driver)
  		return 0;
  
  	udev = to_usb_device(dev);
  	if (!usb_driver_applicable(udev, new_udriver))
  		return 0;
  
  	ret = device_reprobe(dev);
  	if (ret && ret != -EPROBE_DEFER)
  		dev_err(dev, "Failed to reprobe device (error %d)\n", ret);
  
  	return 0;
  }
  
  /**
   * usb_register_device_driver - register a USB device (not interface) driver
   * @new_udriver: USB operations for the device driver
   * @owner: module owner of this driver.
   *
   * 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.
   *
   * Return: 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 = 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;
  	new_udriver->drvwrap.driver.dev_groups = new_udriver->dev_groups;
  
  	retval = driver_register(&new_udriver->drvwrap.driver);
  
  	if (!retval) {
  		pr_info("%s: registered new device driver %s\n",
  			usbcore_name, new_udriver->name);
  		/*
  		 * Check whether any device could be better served with
  		 * this new driver
  		 */
  		bus_for_each_dev(&usb_bus_type, NULL, new_udriver,
  				 __usb_bus_reprobe_drivers);
  	} else {
  		pr_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);
  }
  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.
   * @mod_name: module name string
   *
   * 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.
   *
   * Return: 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.
   */
  int usb_register_driver(struct usb_driver *new_driver, struct module *owner,
  			const char *mod_name)
  {
  	int retval = 0;
  
  	if (usb_disabled())
  		return -ENODEV;
  
  	new_driver->drvwrap.for_devices = 0;
  	new_driver->drvwrap.driver.name = 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;
  	new_driver->drvwrap.driver.mod_name = mod_name;
  	new_driver->drvwrap.driver.dev_groups = new_driver->dev_groups;
  	spin_lock_init(&new_driver->dynids.lock);
  	INIT_LIST_HEAD(&new_driver->dynids.list);
  
  	retval = driver_register(&new_driver->drvwrap.driver);
  	if (retval)
  		goto out;
  
  	retval = usb_create_newid_files(new_driver);
  	if (retval)
  		goto out_newid;
  
  	pr_info("%s: registered new interface driver %s\n",
  			usbcore_name, new_driver->name);
  
  out:
  	return retval;
  
  out_newid:
  	driver_unregister(&new_driver->drvwrap.driver);
  
  	pr_err("%s: error %d registering interface driver %s\n",
  		usbcore_name, retval, new_driver->name);
  	goto out;
  }
  EXPORT_SYMBOL_GPL(usb_register_driver);
  
  /**
   * usb_deregister - unregister a USB interface driver
   * @driver: USB operations of the interface driver to unregister
   * 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)
  {
  	pr_info("%s: deregistering interface driver %s\n",
  			usbcore_name, driver->name);
  
  	usb_remove_newid_files(driver);
  	driver_unregister(&driver->drvwrap.driver);
  	usb_free_dynids(driver);
  }
  EXPORT_SYMBOL_GPL(usb_deregister);
  
  /* Forced unbinding of a USB interface driver, either because
   * it doesn't support pre_reset/post_reset/reset_resume or
   * because it doesn't support suspend/resume.
   *
   * The caller must hold @intf's device's lock, but not @intf's lock.
   */
  void usb_forced_unbind_intf(struct usb_interface *intf)
  {
  	struct usb_driver *driver = to_usb_driver(intf->dev.driver);
  
  	dev_dbg(&intf->dev, "forced unbind\n");
  	usb_driver_release_interface(driver, intf);
  
  	/* Mark the interface for later rebinding */
  	intf->needs_binding = 1;
  }
  
  /*
   * Unbind drivers for @udev's marked interfaces.  These interfaces have
   * the needs_binding flag set, for example by usb_resume_interface().
   *
   * The caller must hold @udev's device lock.
   */
  static void unbind_marked_interfaces(struct usb_device *udev)
  {
  	struct usb_host_config	*config;
  	int			i;
  	struct usb_interface	*intf;
  
  	config = udev->actconfig;
  	if (config) {
  		for (i = 0; i < config->desc.bNumInterfaces; ++i) {
  			intf = config->interface[i];
  			if (intf->dev.driver && intf->needs_binding)
  				usb_forced_unbind_intf(intf);
  		}
  	}
  }
  
  /* Delayed forced unbinding of a USB interface driver and scan
   * for rebinding.
   *
   * The caller must hold @intf's device's lock, but not @intf's lock.
   *
   * Note: Rebinds will be skipped if a system sleep transition is in
   * progress and the PM "complete" callback hasn't occurred yet.
   */
  static void usb_rebind_intf(struct usb_interface *intf)
  {
  	int rc;
  
  	/* Delayed unbind of an existing driver */
  	if (intf->dev.driver)
  		usb_forced_unbind_intf(intf);
  
  	/* Try to rebind the interface */
  	if (!intf->dev.power.is_prepared) {
  		intf->needs_binding = 0;
  		rc = device_attach(&intf->dev);
  		if (rc < 0 && rc != -EPROBE_DEFER)
  			dev_warn(&intf->dev, "rebind failed: %d\n", rc);
  	}
  }
  
  /*
   * Rebind drivers to @udev's marked interfaces.  These interfaces have
   * the needs_binding flag set.
   *
   * The caller must hold @udev's device lock.
   */
  static void rebind_marked_interfaces(struct usb_device *udev)
  {
  	struct usb_host_config	*config;
  	int			i;
  	struct usb_interface	*intf;
  
  	config = udev->actconfig;
  	if (config) {
  		for (i = 0; i < config->desc.bNumInterfaces; ++i) {
  			intf = config->interface[i];
  			if (intf->needs_binding)
  				usb_rebind_intf(intf);
  		}
  	}
  }
  
  /*
   * Unbind all of @udev's marked interfaces and then rebind all of them.
   * This ordering is necessary because some drivers claim several interfaces
   * when they are first probed.
   *
   * The caller must hold @udev's device lock.
   */
  void usb_unbind_and_rebind_marked_interfaces(struct usb_device *udev)
  {
  	unbind_marked_interfaces(udev);
  	rebind_marked_interfaces(udev);
  }
  
  #ifdef CONFIG_PM
  
  /* Unbind drivers for @udev's interfaces that don't support suspend/resume
   * There is no check for reset_resume here because it can be determined
   * only during resume whether reset_resume is needed.
   *
   * The caller must hold @udev's device lock.
   */
  static void unbind_no_pm_drivers_interfaces(struct usb_device *udev)
  {
  	struct usb_host_config	*config;
  	int			i;
  	struct usb_interface	*intf;
  	struct usb_driver	*drv;
  
  	config = udev->actconfig;
  	if (config) {
  		for (i = 0; i < config->desc.bNumInterfaces; ++i) {
  			intf = config->interface[i];
  
  			if (intf->dev.driver) {
  				drv = to_usb_driver(intf->dev.driver);
  				if (!drv->suspend || !drv->resume)
  					usb_forced_unbind_intf(intf);
  			}
  		}
  	}
  }
  
  static int usb_suspend_device(struct usb_device *udev, pm_message_t msg)
  {
  	struct usb_device_driver	*udriver;
  	int				status = 0;
  
  	if (udev->state == USB_STATE_NOTATTACHED ||
  			udev->state == USB_STATE_SUSPENDED)
  		goto done;
  
  	/* 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 {
  		udev->do_remote_wakeup = 0;
  		udriver = &usb_generic_driver;
  	}
  	if (udriver->suspend)
  		status = udriver->suspend(udev, msg);
  	if (status == 0 && udriver->generic_subclass)
  		status = usb_generic_driver_suspend(udev, msg);
  
   done:
  	dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
  	return status;
  }
  
  static int usb_resume_device(struct usb_device *udev, pm_message_t msg)
  {
  	struct usb_device_driver	*udriver;
  	int				status = 0;
  
  	if (udev->state == USB_STATE_NOTATTACHED)
  		goto done;
  
  	/* Can't resume it if it doesn't have a driver. */
  	if (udev->dev.driver == NULL) {
  		status = -ENOTCONN;
  		goto done;
  	}
  
  	/* Non-root devices on a full/low-speed bus must wait for their
  	 * companion high-speed root hub, in case a handoff is needed.
  	 */
  	if (!PMSG_IS_AUTO(msg) && udev->parent && udev->bus->hs_companion)
  		device_pm_wait_for_dev(&udev->dev,
  				&udev->bus->hs_companion->root_hub->dev);
  
  	if (udev->quirks & USB_QUIRK_RESET_RESUME)
  		udev->reset_resume = 1;
  
  	udriver = to_usb_device_driver(udev->dev.driver);
  	if (udriver->generic_subclass)
  		status = usb_generic_driver_resume(udev, msg);
  	if (status == 0 && udriver->resume)
  		status = udriver->resume(udev, msg);
  
   done:
  	dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
  	return status;
  }
  
  static int usb_suspend_interface(struct usb_device *udev,
  		struct usb_interface *intf, pm_message_t msg)
  {
  	struct usb_driver	*driver;
  	int			status = 0;
  
  	if (udev->state == USB_STATE_NOTATTACHED ||
  			intf->condition == USB_INTERFACE_UNBOUND)
  		goto done;
  	driver = to_usb_driver(intf->dev.driver);
  
  	/* at this time we know the driver supports suspend */
  	status = driver->suspend(intf, msg);
  	if (status && !PMSG_IS_AUTO(msg))
  		dev_err(&intf->dev, "suspend error %d\n", status);
  
   done:
  	dev_vdbg(&intf->dev, "%s: status %d\n", __func__, status);
  	return status;
  }
  
  static int usb_resume_interface(struct usb_device *udev,
  		struct usb_interface *intf, pm_message_t msg, int reset_resume)
  {
  	struct usb_driver	*driver;
  	int			status = 0;
  
  	if (udev->state == USB_STATE_NOTATTACHED)
  		goto done;
  
  	/* Don't let autoresume interfere with unbinding */
  	if (intf->condition == USB_INTERFACE_UNBINDING)
  		goto done;
  
  	/* Can't resume it if it doesn't have a driver. */
  	if (intf->condition == USB_INTERFACE_UNBOUND) {
  
  		/* Carry out a deferred switch to altsetting 0 */
  		if (intf->needs_altsetting0 && !intf->dev.power.is_prepared) {
  			usb_set_interface(udev, intf->altsetting[0].
  					desc.bInterfaceNumber, 0);
  			intf->needs_altsetting0 = 0;
  		}
  		goto done;
  	}
  
  	/* Don't resume if the interface is marked for rebinding */
  	if (intf->needs_binding)
  		goto done;
  	driver = to_usb_driver(intf->dev.driver);
  
  	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 {
  			intf->needs_binding = 1;
  			dev_dbg(&intf->dev, "no reset_resume for driver %s?\n",
  					driver->name);
  		}
  	} else {
  		status = driver->resume(intf);
  		if (status)
  			dev_err(&intf->dev, "resume error %d\n", status);
  	}
  
  done:
  	dev_vdbg(&intf->dev, "%s: status %d\n", __func__, status);
  
  	/* Later we will unbind the driver and/or reprobe, if necessary */
  	return status;
  }
  
  /**
   * 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.  When the routine is called in
   * autosuspend, 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, but when called from system sleep, all error
   * from suspend methods of interfaces and the non-root-hub device itself
   * are simply ignored, so all suspended interfaces are only resumed
   * to the device's state when @udev is root-hub and its suspend method
   * returns failure.
   *
   * Autosuspend requests originating from a child device or an interface
   * driver may be made without the protection of @udev's device lock, but
   * all other suspend calls will hold the lock.  Usbcore will insure that
   * method calls do not arrive during bind, unbind, or reset operations.
   * However drivers must be prepared to handle suspend calls arriving at
   * unpredictable times.
   *
   * This routine can run only in process context.
   *
   * Return: 0 if the suspend succeeded.
   */
  static int usb_suspend_both(struct usb_device *udev, pm_message_t msg)
  {
  	int			status = 0;
  	int			i = 0, n = 0;
  	struct usb_interface	*intf;
  
  	if (udev->state == USB_STATE_NOTATTACHED ||
  			udev->state == USB_STATE_SUSPENDED)
  		goto done;
  
  	/* Suspend all the interfaces and then udev itself */
  	if (udev->actconfig) {
  		n = udev->actconfig->desc.bNumInterfaces;
  		for (i = n - 1; i >= 0; --i) {
  			intf = udev->actconfig->interface[i];
  			status = usb_suspend_interface(udev, intf, msg);
  
  			/* Ignore errors during system sleep transitions */
  			if (!PMSG_IS_AUTO(msg))
  				status = 0;
  			if (status != 0)
  				break;
  		}
  	}
  	if (status == 0) {
  		status = usb_suspend_device(udev, msg);
  
  		/*
  		 * Ignore errors from non-root-hub devices during
  		 * system sleep transitions.  For the most part,
  		 * these devices should go to low power anyway when
  		 * the entire bus is suspended.
  		 */
  		if (udev->parent && !PMSG_IS_AUTO(msg))
  			status = 0;
  
  		/*
  		 * If the device is inaccessible, don't try to resume
  		 * suspended interfaces and just return the error.
  		 */
  		if (status && status != -EBUSY) {
  			int err;
  			u16 devstat;
  
  			err = usb_get_std_status(udev, USB_RECIP_DEVICE, 0,
  						 &devstat);
  			if (err) {
  				dev_err(&udev->dev,
  					"Failed to suspend device, error %d\n",
  					status);
  				goto done;
  			}
  		}
  	}
  
  	/* If the suspend failed, resume interfaces that did get suspended */
  	if (status != 0) {
  		if (udev->actconfig) {
  			msg.event ^= (PM_EVENT_SUSPEND | PM_EVENT_RESUME);
  			while (++i < n) {
  				intf = udev->actconfig->interface[i];
  				usb_resume_interface(udev, intf, msg, 0);
  			}
  		}
  
  	/* If the suspend succeeded then prevent any more URB submissions
  	 * and flush any outstanding URBs.
  	 */
  	} else {
  		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]);
  		}
  	}
  
   done:
  	dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
  	return status;
  }
  
  /**
   * usb_resume_both - resume a USB device and its interfaces
   * @udev: the usb_device to resume
   * @msg: Power Management message describing this state transition
   *
   * 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.
   *
   * Autoresume requests originating from a child device or an interface
   * driver may be made without the protection of @udev's device lock, but
   * all other resume calls will hold the lock.  Usbcore will insure that
   * method calls do not arrive during bind, unbind, or reset operations.
   * However drivers must be prepared to handle resume calls arriving at
   * unpredictable times.
   *
   * This routine can run only in process context.
   *
   * Return: 0 on success.
   */
  static int usb_resume_both(struct usb_device *udev, pm_message_t msg)
  {
  	int			status = 0;
  	int			i;
  	struct usb_interface	*intf;
  
  	if (udev->state == USB_STATE_NOTATTACHED) {
  		status = -ENODEV;
  		goto done;
  	}
  	udev->can_submit = 1;
  
  	/* Resume the device */
  	if (udev->state == USB_STATE_SUSPENDED || udev->reset_resume)
  		status = usb_resume_device(udev, msg);
  
  	/* Resume the interfaces */
  	if (status == 0 && udev->actconfig) {
  		for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
  			intf = udev->actconfig->interface[i];
  			usb_resume_interface(udev, intf, msg,
  					udev->reset_resume);
  		}
  	}
  	usb_mark_last_busy(udev);
  
   done:
  	dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
  	if (!status)
  		udev->reset_resume = 0;
  	return status;
  }
  
  static void choose_wakeup(struct usb_device *udev, pm_message_t msg)
  {
  	int	w;
  
  	/* Remote wakeup is needed only when we actually go to sleep.
  	 * For things like FREEZE and QUIESCE, if the device is already
  	 * autosuspended then its current wakeup setting is okay.
  	 */
  	if (msg.event == PM_EVENT_FREEZE || msg.event == PM_EVENT_QUIESCE) {
  		if (udev->state != USB_STATE_SUSPENDED)
  			udev->do_remote_wakeup = 0;
  		return;
  	}
  
  	/* Enable remote wakeup if it is allowed, even if no interface drivers
  	 * actually want it.
  	 */
  	w = device_may_wakeup(&udev->dev);
  
  	/* If the device is autosuspended with the wrong wakeup setting,
  	 * autoresume now so the setting can be changed.
  	 */
  	if (udev->state == USB_STATE_SUSPENDED && w != udev->do_remote_wakeup)
  		pm_runtime_resume(&udev->dev);
  	udev->do_remote_wakeup = w;
  }
  
  /* The device lock is held by the PM core */
  int usb_suspend(struct device *dev, pm_message_t msg)
  {
  	struct usb_device	*udev = to_usb_device(dev);
  	int r;
  
  	unbind_no_pm_drivers_interfaces(udev);
  
  	/* From now on we are sure all drivers support suspend/resume
  	 * but not necessarily reset_resume()
  	 * so we may still need to unbind and rebind upon resume
  	 */
  	choose_wakeup(udev, msg);
  	r = usb_suspend_both(udev, msg);
  	if (r)
  		return r;
  
  	if (udev->quirks & USB_QUIRK_DISCONNECT_SUSPEND)
  		usb_port_disable(udev);
  
  	return 0;
  }
  
  /* The device lock is held by the PM core */
  int usb_resume_complete(struct device *dev)
  {
  	struct usb_device *udev = to_usb_device(dev);
  
  	/* For PM complete calls, all we do is rebind interfaces
  	 * whose needs_binding flag is set
  	 */
  	if (udev->state != USB_STATE_NOTATTACHED)
  		rebind_marked_interfaces(udev);
  	return 0;
  }
  
  /* The device lock is held by the PM core */
  int usb_resume(struct device *dev, pm_message_t msg)
  {
  	struct usb_device	*udev = to_usb_device(dev);
  	int			status;
  
  	/* For all calls, take the device back to full power and
  	 * tell the PM core in case it was autosuspended previously.
  	 * Unbind the interfaces that will need rebinding later,
  	 * because they fail to support reset_resume.
  	 * (This can't be done in usb_resume_interface()
  	 * above because it doesn't own the right set of locks.)
  	 */
  	status = usb_resume_both(udev, msg);
  	if (status == 0) {
  		pm_runtime_disable(dev);
  		pm_runtime_set_active(dev);
  		pm_runtime_enable(dev);
  		unbind_marked_interfaces(udev);
  	}
  
  	/* Avoid PM error messages for devices disconnected while suspended
  	 * as we'll display regular disconnect messages just a bit later.
  	 */
  	if (status == -ENODEV || status == -ESHUTDOWN)
  		status = 0;
  	return status;
  }
  
  /**
   * usb_enable_autosuspend - allow a USB device to be autosuspended
   * @udev: the USB device which may be autosuspended
   *
   * This routine allows @udev to be autosuspended.  An autosuspend won't
   * take place until the autosuspend_delay has elapsed and all the other
   * necessary conditions are satisfied.
   *
   * The caller must hold @udev's device lock.
   */
  void usb_enable_autosuspend(struct usb_device *udev)
  {
  	pm_runtime_allow(&udev->dev);
  }
  EXPORT_SYMBOL_GPL(usb_enable_autosuspend);
  
  /**
   * usb_disable_autosuspend - prevent a USB device from being autosuspended
   * @udev: the USB device which may not be autosuspended
   *
   * This routine prevents @udev from being autosuspended and wakes it up
   * if it is already autosuspended.
   *
   * The caller must hold @udev's device lock.
   */
  void usb_disable_autosuspend(struct usb_device *udev)
  {
  	pm_runtime_forbid(&udev->dev);
  }
  EXPORT_SYMBOL_GPL(usb_disable_autosuspend);
  
  /**
   * usb_autosuspend_device - delayed autosuspend of a USB device and its interfaces
   * @udev: the usb_device to autosuspend
   *
   * 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.
   *
   * @udev's usage counter is decremented; if it drops to 0 and all the
   * interfaces are inactive then a delayed autosuspend will be attempted.
   * The attempt may fail (see autosuspend_check()).
   *
   * The caller must hold @udev's device lock.
   *
   * This routine can run only in process context.
   */
  void usb_autosuspend_device(struct usb_device *udev)
  {
  	int	status;
  
  	usb_mark_last_busy(udev);
  	status = pm_runtime_put_sync_autosuspend(&udev->dev);
  	dev_vdbg(&udev->dev, "%s: cnt %d -> %d\n",
  			__func__, atomic_read(&udev->dev.power.usage_count),
  			status);
  }
  
  /**
   * usb_autoresume_device - immediately autoresume a USB device and its interfaces
   * @udev: the usb_device to autoresume
   *
   * This routine should be called when a core subsystem wants to use @udev
   * 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.
   *
   * @udev's usage counter is incremented to prevent subsequent autosuspends.
   * However if the autoresume fails then the usage counter is re-decremented.
   *
   * The caller must hold @udev's device lock.
   *
   * This routine can run only in process context.
   *
   * Return: 0 on success. A negative error code otherwise.
   */
  int usb_autoresume_device(struct usb_device *udev)
  {
  	int	status;
  
  	status = pm_runtime_get_sync(&udev->dev);
  	if (status < 0)
  		pm_runtime_put_sync(&udev->dev);
  	dev_vdbg(&udev->dev, "%s: cnt %d -> %d\n",
  			__func__, atomic_read(&udev->dev.power.usage_count),
  			status);
  	if (status > 0)
  		status = 0;
  	return status;
  }
  
  /**
   * usb_autopm_put_interface - decrement a USB interface's PM-usage counter
   * @intf: the usb_interface whose counter should be decremented
   *
   * 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 attempted.  The
   * attempt may fail (see autosuspend_check()).
   *
   * This routine can run only in process context.
   */
  void usb_autopm_put_interface(struct usb_interface *intf)
  {
  	struct usb_device	*udev = interface_to_usbdev(intf);
  	int			status;
  
  	usb_mark_last_busy(udev);
  	status = pm_runtime_put_sync(&intf->dev);
  	dev_vdbg(&intf->dev, "%s: cnt %d -> %d\n",
  			__func__, atomic_read(&intf->dev.power.usage_count),
  			status);
  }
  EXPORT_SYMBOL_GPL(usb_autopm_put_interface);
  
  /**
   * usb_autopm_put_interface_async - decrement a USB interface's PM-usage counter
   * @intf: the usb_interface whose counter should be decremented
   *
   * This routine does much the same thing as usb_autopm_put_interface():
   * It decrements @intf's usage counter and schedules a delayed
   * autosuspend request if the counter is <= 0.  The difference is that it
   * does not perform any synchronization; callers should hold a private
   * lock and handle all synchronization issues themselves.
   *
   * Typically a driver would call this routine during an URB's completion
   * handler, if no more URBs were pending.
   *
   * This routine can run in atomic context.
   */
  void usb_autopm_put_interface_async(struct usb_interface *intf)
  {
  	struct usb_device	*udev = interface_to_usbdev(intf);
  	int			status;
  
  	usb_mark_last_busy(udev);
  	status = pm_runtime_put(&intf->dev);
  	dev_vdbg(&intf->dev, "%s: cnt %d -> %d\n",
  			__func__, atomic_read(&intf->dev.power.usage_count),
  			status);
  }
  EXPORT_SYMBOL_GPL(usb_autopm_put_interface_async);
  
  /**
   * usb_autopm_put_interface_no_suspend - decrement a USB interface's PM-usage counter
   * @intf: the usb_interface whose counter should be decremented
   *
   * This routine decrements @intf's usage counter but does not carry out an
   * autosuspend.
   *
   * This routine can run in atomic context.
   */
  void usb_autopm_put_interface_no_suspend(struct usb_interface *intf)
  {
  	struct usb_device	*udev = interface_to_usbdev(intf);
  
  	usb_mark_last_busy(udev);
  	pm_runtime_put_noidle(&intf->dev);
  }
  EXPORT_SYMBOL_GPL(usb_autopm_put_interface_no_suspend);
  
  /**
   * usb_autopm_get_interface - increment a USB interface's PM-usage counter
   * @intf: the usb_interface whose counter should be incremented
   *
   * 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.
   *
   * @intf's usage counter is incremented to prevent subsequent autosuspends.
   * However if the autoresume fails then the counter is re-decremented.
   *
   * This routine can run only in process context.
   *
   * Return: 0 on success.
   */
  int usb_autopm_get_interface(struct usb_interface *intf)
  {
  	int	status;
  
  	status = pm_runtime_get_sync(&intf->dev);
  	if (status < 0)
  		pm_runtime_put_sync(&intf->dev);
  	dev_vdbg(&intf->dev, "%s: cnt %d -> %d\n",
  			__func__, atomic_read(&intf->dev.power.usage_count),
  			status);
  	if (status > 0)
  		status = 0;
  	return status;
  }
  EXPORT_SYMBOL_GPL(usb_autopm_get_interface);
  
  /**
   * usb_autopm_get_interface_async - increment a USB interface's PM-usage counter
   * @intf: the usb_interface whose counter should be incremented
   *
   * This routine does much the same thing as
   * usb_autopm_get_interface(): It increments @intf's usage counter and
   * queues an autoresume request if the device is suspended.  The
   * differences are that it does not perform any synchronization (callers
   * should hold a private lock and handle all synchronization issues
   * themselves), and it does not autoresume the device directly (it only
   * queues a request).  After a successful call, the device may not yet be
   * resumed.
   *
   * This routine can run in atomic context.
   *
   * Return: 0 on success. A negative error code otherwise.
   */
  int usb_autopm_get_interface_async(struct usb_interface *intf)
  {
  	int	status;
  
  	status = pm_runtime_get(&intf->dev);
  	if (status < 0 && status != -EINPROGRESS)
  		pm_runtime_put_noidle(&intf->dev);
  	dev_vdbg(&intf->dev, "%s: cnt %d -> %d\n",
  			__func__, atomic_read(&intf->dev.power.usage_count),
  			status);
  	if (status > 0 || status == -EINPROGRESS)
  		status = 0;
  	return status;
  }
  EXPORT_SYMBOL_GPL(usb_autopm_get_interface_async);
  
  /**
   * usb_autopm_get_interface_no_resume - increment a USB interface's PM-usage counter
   * @intf: the usb_interface whose counter should be incremented
   *
   * This routine increments @intf's usage counter but does not carry out an
   * autoresume.
   *
   * This routine can run in atomic context.
   */
  void usb_autopm_get_interface_no_resume(struct usb_interface *intf)
  {
  	struct usb_device	*udev = interface_to_usbdev(intf);
  
  	usb_mark_last_busy(udev);
  	pm_runtime_get_noresume(&intf->dev);
  }
  EXPORT_SYMBOL_GPL(usb_autopm_get_interface_no_resume);
  
  /* Internal routine to check whether we may autosuspend a device. */
  static int autosuspend_check(struct usb_device *udev)
  {
  	int			w, i;
  	struct usb_interface	*intf;
  
  	if (udev->state == USB_STATE_NOTATTACHED)
  		return -ENODEV;
  
  	/* Fail if autosuspend is disabled, or any interfaces are in use, or
  	 * any interface drivers require remote wakeup but it isn't available.
  	 */
  	w = 0;
  	if (udev->actconfig) {
  		for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
  			intf = udev->actconfig->interface[i];
  
  			/* We don't need to check interfaces that are
  			 * disabled for runtime PM.  Either they are unbound
  			 * or else their drivers don't support autosuspend
  			 * and so they are permanently active.
  			 */
  			if (intf->dev.power.disable_depth)
  				continue;
  			if (atomic_read(&intf->dev.power.usage_count) > 0)
  				return -EBUSY;
  			w |= intf->needs_remote_wakeup;
  
  			/* Don't allow autosuspend if the device will need
  			 * a reset-resume and any of its interface drivers
  			 * doesn't include support or needs remote wakeup.
  			 */
  			if (udev->quirks & USB_QUIRK_RESET_RESUME) {
  				struct usb_driver *driver;
  
  				driver = to_usb_driver(intf->dev.driver);
  				if (!driver->reset_resume ||
  						intf->needs_remote_wakeup)
  					return -EOPNOTSUPP;
  			}
  		}
  	}
  	if (w && !device_can_wakeup(&udev->dev)) {
  		dev_dbg(&udev->dev, "remote wakeup needed for autosuspend\n");
  		return -EOPNOTSUPP;
  	}
  
  	/*
  	 * If the device is a direct child of the root hub and the HCD
  	 * doesn't handle wakeup requests, don't allow autosuspend when
  	 * wakeup is needed.
  	 */
  	if (w && udev->parent == udev->bus->root_hub &&
  			bus_to_hcd(udev->bus)->cant_recv_wakeups) {
  		dev_dbg(&udev->dev, "HCD doesn't handle wakeup requests\n");
  		return -EOPNOTSUPP;
  	}
  
  	udev->do_remote_wakeup = w;
  	return 0;
  }
  
  int usb_runtime_suspend(struct device *dev)
  {
  	struct usb_device	*udev = to_usb_device(dev);
  	int			status;
  
  	/* A USB device can be suspended if it passes the various autosuspend
  	 * checks.  Runtime suspend for a USB device means suspending all the
  	 * interfaces and then the device itself.
  	 */
  	if (autosuspend_check(udev) != 0)
  		return -EAGAIN;
  
  	status = usb_suspend_both(udev, PMSG_AUTO_SUSPEND);
  
  	/* Allow a retry if autosuspend failed temporarily */
  	if (status == -EAGAIN || status == -EBUSY)
  		usb_mark_last_busy(udev);
  
  	/*
  	 * The PM core reacts badly unless the return code is 0,
  	 * -EAGAIN, or -EBUSY, so always return -EBUSY on an error
  	 * (except for root hubs, because they don't suspend through
  	 * an upstream port like other USB devices).
  	 */
  	if (status != 0 && udev->parent)
  		return -EBUSY;
  	return status;
  }
  
  int usb_runtime_resume(struct device *dev)
  {
  	struct usb_device	*udev = to_usb_device(dev);
  	int			status;
  
  	/* Runtime resume for a USB device means resuming both the device
  	 * and all its interfaces.
  	 */
  	status = usb_resume_both(udev, PMSG_AUTO_RESUME);
  	return status;
  }
  
  int usb_runtime_idle(struct device *dev)
  {
  	struct usb_device	*udev = to_usb_device(dev);
  
  	/* An idle USB device can be suspended if it passes the various
  	 * autosuspend checks.
  	 */
  	if (autosuspend_check(udev) == 0)
  		pm_runtime_autosuspend(dev);
  	/* Tell the core not to suspend it, though. */
  	return -EBUSY;
  }
  
  static int usb_set_usb2_hardware_lpm(struct usb_device *udev, int enable)
  {
  	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
  	int ret = -EPERM;
  
  	if (hcd->driver->set_usb2_hw_lpm) {
  		ret = hcd->driver->set_usb2_hw_lpm(hcd, udev, enable);
  		if (!ret)
  			udev->usb2_hw_lpm_enabled = enable;
  	}
  
  	return ret;
  }
  
  int usb_enable_usb2_hardware_lpm(struct usb_device *udev)
  {
  	if (!udev->usb2_hw_lpm_capable ||
  	    !udev->usb2_hw_lpm_allowed ||
  	    udev->usb2_hw_lpm_enabled)
  		return 0;
  
  	return usb_set_usb2_hardware_lpm(udev, 1);
  }
  
  int usb_disable_usb2_hardware_lpm(struct usb_device *udev)
  {
  	if (!udev->usb2_hw_lpm_enabled)
  		return 0;
  
  	return usb_set_usb2_hardware_lpm(udev, 0);
  }
  
  #endif /* CONFIG_PM */
  
  struct bus_type usb_bus_type = {
  	.name =		"usb",
  	.match =	usb_device_match,
  	.uevent =	usb_uevent,
  	.need_parent_lock =	true,
  };
  