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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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
  * 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;
 
     /*
      * For FREEZE/QUIESCE, disable remote wakeups so no interrupts get
      * generated.
      */
     if (msg.event == PM_EVENT_FREEZE || msg.event == PM_EVENT_QUIESCE) {
         w = 0;
 
     } else {
         /*
          * 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,
 };

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