text: #ifndef __LINUX_USB_H
  #define __LINUX_USB_H
  
  #include <linux/mod_devicetable.h>
  #include <linux/usb/ch9.h>
  
  #define USB_MAJOR			180
  #define USB_DEVICE_MAJOR		189
  
  
  #ifdef __KERNEL__
  
  #include <linux/errno.h>        /* for -ENODEV */
  #include <linux/delay.h>	/* for mdelay() */
  #include <linux/interrupt.h>	/* for in_interrupt() */
  #include <linux/list.h>		/* for struct list_head */
  #include <linux/kref.h>		/* for struct kref */
  #include <linux/device.h>	/* for struct device */
  #include <linux/fs.h>		/* for struct file_operations */
  #include <linux/completion.h>	/* for struct completion */
  #include <linux/sched.h>	/* for current && schedule_timeout */
  #include <linux/mutex.h>	/* for struct mutex */
  #include <linux/pm_runtime.h>	/* for runtime PM */
  
  struct usb_device;
  struct usb_driver;
  struct wusb_dev;
  
  /*-------------------------------------------------------------------------*/
  
  /*
   * Host-side wrappers for standard USB descriptors ... these are parsed
   * from the data provided by devices.  Parsing turns them from a flat
   * sequence of descriptors into a hierarchy:
   *
   *  - devices have one (usually) or more configs;
   *  - configs have one (often) or more interfaces;
   *  - interfaces have one (usually) or more settings;
   *  - each interface setting has zero or (usually) more endpoints.
   *  - a SuperSpeed endpoint has a companion descriptor
   *
   * And there might be other descriptors mixed in with those.
   *
   * Devices may also have class-specific or vendor-specific descriptors.
   */
  
  struct ep_device;
  
  /**
   * struct usb_host_endpoint - host-side endpoint descriptor and queue
   * @desc: descriptor for this endpoint, wMaxPacketSize in native byteorder
   * @ss_ep_comp: SuperSpeed companion descriptor for this endpoint
   * @urb_list: urbs queued to this endpoint; maintained by usbcore
   * @hcpriv: for use by HCD; typically holds hardware dma queue head (QH)
   *	with one or more transfer descriptors (TDs) per urb
   * @ep_dev: ep_device for sysfs info
   * @extra: descriptors following this endpoint in the configuration
   * @extralen: how many bytes of "extra" are valid
   * @enabled: URBs may be submitted to this endpoint
   * @streams: number of USB-3 streams allocated on the endpoint
   *
   * USB requests are always queued to a given endpoint, identified by a
   * descriptor within an active interface in a given USB configuration.
   */
  struct usb_host_endpoint {
  	struct usb_endpoint_descriptor		desc;
  	struct usb_ss_ep_comp_descriptor	ss_ep_comp;
  	struct list_head		urb_list;
  	void				*hcpriv;
  	struct ep_device		*ep_dev;	/* For sysfs info */
  
  	unsigned char *extra;   /* Extra descriptors */
  	int extralen;
  	int enabled;
  	int streams;
  };
  
  /* host-side wrapper for one interface setting's parsed descriptors */
  struct usb_host_interface {
  	struct usb_interface_descriptor	desc;
  
  	int extralen;
  	unsigned char *extra;   /* Extra descriptors */
  
  	/* array of desc.bNumEndpoints endpoints associated with this
  	 * interface setting.  these will be in no particular order.
  	 */
  	struct usb_host_endpoint *endpoint;
  
  	char *string;		/* iInterface string, if present */
  };
  
  enum usb_interface_condition {
  	USB_INTERFACE_UNBOUND = 0,
  	USB_INTERFACE_BINDING,
  	USB_INTERFACE_BOUND,
  	USB_INTERFACE_UNBINDING,
  };
  
  /**
   * struct usb_interface - what usb device drivers talk to
   * @altsetting: array of interface structures, one for each alternate
   *	setting that may be selected.  Each one includes a set of
   *	endpoint configurations.  They will be in no particular order.
   * @cur_altsetting: the current altsetting.
   * @num_altsetting: number of altsettings defined.
   * @intf_assoc: interface association descriptor
   * @minor: the minor number assigned to this interface, if this
   *	interface is bound to a driver that uses the USB major number.
   *	If this interface does not use the USB major, this field should
   *	be unused.  The driver should set this value in the probe()
   *	function of the driver, after it has been assigned a minor
   *	number from the USB core by calling usb_register_dev().
   * @condition: binding state of the interface: not bound, binding
   *	(in probe()), bound to a driver, or unbinding (in disconnect())
   * @sysfs_files_created: sysfs attributes exist
   * @ep_devs_created: endpoint child pseudo-devices exist
   * @unregistering: flag set when the interface is being unregistered
   * @needs_remote_wakeup: flag set when the driver requires remote-wakeup
   *	capability during autosuspend.
   * @needs_altsetting0: flag set when a set-interface request for altsetting 0
   *	has been deferred.
   * @needs_binding: flag set when the driver should be re-probed or unbound
   *	following a reset or suspend operation it doesn't support.
   * @dev: driver model's view of this device
   * @usb_dev: if an interface is bound to the USB major, this will point
   *	to the sysfs representation for that device.
   * @pm_usage_cnt: PM usage counter for this interface
   * @reset_ws: Used for scheduling resets from atomic context.
   * @resetting_device: USB core reset the device, so use alt setting 0 as
   *	current; needs bandwidth alloc after reset.
   *
   * USB device drivers attach to interfaces on a physical device.  Each
   * interface encapsulates a single high level function, such as feeding
   * an audio stream to a speaker or reporting a change in a volume control.
   * Many USB devices only have one interface.  The protocol used to talk to
   * an interface's endpoints can be defined in a usb "class" specification,
   * or by a product's vendor.  The (default) control endpoint is part of
   * every interface, but is never listed among the interface's descriptors.
   *
   * The driver that is bound to the interface can use standard driver model
   * calls such as dev_get_drvdata() on the dev member of this structure.
   *
   * Each interface may have alternate settings.  The initial configuration
   * of a device sets altsetting 0, but the device driver can change
   * that setting using usb_set_interface().  Alternate settings are often
   * used to control the use of periodic endpoints, such as by having
   * different endpoints use different amounts of reserved USB bandwidth.
   * All standards-conformant USB devices that use isochronous endpoints
   * will use them in non-default settings.
   *
   * The USB specification says that alternate setting numbers must run from
   * 0 to one less than the total number of alternate settings.  But some
   * devices manage to mess this up, and the structures aren't necessarily
   * stored in numerical order anyhow.  Use usb_altnum_to_altsetting() to
   * look up an alternate setting in the altsetting array based on its number.
   */
  struct usb_interface {
  	/* array of alternate settings for this interface,
  	 * stored in no particular order */
  	struct usb_host_interface *altsetting;
  
  	struct usb_host_interface *cur_altsetting;	/* the currently
  					 * active alternate setting */
  	unsigned num_altsetting;	/* number of alternate settings */
  
  	/* If there is an interface association descriptor then it will list
  	 * the associated interfaces */
  	struct usb_interface_assoc_descriptor *intf_assoc;
  
  	int minor;			/* minor number this interface is
  					 * bound to */
  	enum usb_interface_condition condition;		/* state of binding */
  	unsigned sysfs_files_created:1;	/* the sysfs attributes exist */
  	unsigned ep_devs_created:1;	/* endpoint "devices" exist */
  	unsigned unregistering:1;	/* unregistration is in progress */
  	unsigned needs_remote_wakeup:1;	/* driver requires remote wakeup */
  	unsigned needs_altsetting0:1;	/* switch to altsetting 0 is pending */
  	unsigned needs_binding:1;	/* needs delayed unbind/rebind */
  	unsigned resetting_device:1;	/* true: bandwidth alloc after reset */
  
  	struct device dev;		/* interface specific device info */
  	struct device *usb_dev;
  	atomic_t pm_usage_cnt;		/* usage counter for autosuspend */
  	struct work_struct reset_ws;	/* for resets in atomic context */
  };
  #define	to_usb_interface(d) container_of(d, struct usb_interface, dev)
  
  static inline void *usb_get_intfdata(struct usb_interface *intf)
  {
  	return dev_get_drvdata(&intf->dev);
  }
  
  static inline void usb_set_intfdata(struct usb_interface *intf, void *data)
  {
  	dev_set_drvdata(&intf->dev, data);
  }
  
  struct usb_interface *usb_get_intf(struct usb_interface *intf);
  void usb_put_intf(struct usb_interface *intf);
  
  /* Hard limit */
  #define USB_MAXENDPOINTS	30
  /* this maximum is arbitrary */
  #define USB_MAXINTERFACES	32
  #define USB_MAXIADS		(USB_MAXINTERFACES/2)
  
  /*
   * USB Resume Timer: Every Host controller driver should drive the resume
   * signalling on the bus for the amount of time defined by this macro.
   *
   * That way we will have a 'stable' behavior among all HCDs supported by Linux.
   *
   * Note that the USB Specification states we should drive resume for *at least*
   * 20 ms, but it doesn't give an upper bound. This creates two possible
   * situations which we want to avoid:
   *
   * (a) sometimes an msleep(20) might expire slightly before 20 ms, which causes
   * us to fail USB Electrical Tests, thus failing Certification
   *
   * (b) Some (many) devices actually need more than 20 ms of resume signalling,
   * and while we can argue that's against the USB Specification, we don't have
   * control over which devices a certification laboratory will be using for
   * certification. If CertLab uses a device which was tested against Windows and
   * that happens to have relaxed resume signalling rules, we might fall into
   * situations where we fail interoperability and electrical tests.
   *
   * In order to avoid both conditions, we're using a 40 ms resume timeout, which
   * should cope with both LPJ calibration errors and devices not following every
   * detail of the USB Specification.
   */
  #define USB_RESUME_TIMEOUT	40 /* ms */
  
  /**
   * struct usb_interface_cache - long-term representation of a device interface
   * @num_altsetting: number of altsettings defined.
   * @ref: reference counter.
   * @altsetting: variable-length array of interface structures, one for
   *	each alternate setting that may be selected.  Each one includes a
   *	set of endpoint configurations.  They will be in no particular order.
   *
   * These structures persist for the lifetime of a usb_device, unlike
   * struct usb_interface (which persists only as long as its configuration
   * is installed).  The altsetting arrays can be accessed through these
   * structures at any time, permitting comparison of configurations and
   * providing support for the /proc/bus/usb/devices pseudo-file.
   */
  struct usb_interface_cache {
  	unsigned num_altsetting;	/* number of alternate settings */
  	struct kref ref;		/* reference counter */
  
  	/* variable-length array of alternate settings for this interface,
  	 * stored in no particular order */
  	struct usb_host_interface altsetting[0];
  };
  #define	ref_to_usb_interface_cache(r) \
  		container_of(r, struct usb_interface_cache, ref)
  #define	altsetting_to_usb_interface_cache(a) \
  		container_of(a, struct usb_interface_cache, altsetting[0])
  
  /**
   * struct usb_host_config - representation of a device's configuration
   * @desc: the device's configuration descriptor.
   * @string: pointer to the cached version of the iConfiguration string, if
   *	present for this configuration.
   * @intf_assoc: list of any interface association descriptors in this config
   * @interface: array of pointers to usb_interface structures, one for each
   *	interface in the configuration.  The number of interfaces is stored
   *	in desc.bNumInterfaces.  These pointers are valid only while the
   *	the configuration is active.
   * @intf_cache: array of pointers to usb_interface_cache structures, one
   *	for each interface in the configuration.  These structures exist
   *	for the entire life of the device.
   * @extra: pointer to buffer containing all extra descriptors associated
   *	with this configuration (those preceding the first interface
   *	descriptor).
   * @extralen: length of the extra descriptors buffer.
   *
   * USB devices may have multiple configurations, but only one can be active
   * at any time.  Each encapsulates a different operational environment;
   * for example, a dual-speed device would have separate configurations for
   * full-speed and high-speed operation.  The number of configurations
   * available is stored in the device descriptor as bNumConfigurations.
   *
   * A configuration can contain multiple interfaces.  Each corresponds to
   * a different function of the USB device, and all are available whenever
   * the configuration is active.  The USB standard says that interfaces
   * are supposed to be numbered from 0 to desc.bNumInterfaces-1, but a lot
   * of devices get this wrong.  In addition, the interface array is not
   * guaranteed to be sorted in numerical order.  Use usb_ifnum_to_if() to
   * look up an interface entry based on its number.
   *
   * Device drivers should not attempt to activate configurations.  The choice
   * of which configuration to install is a policy decision based on such
   * considerations as available power, functionality provided, and the user's
   * desires (expressed through userspace tools).  However, drivers can call
   * usb_reset_configuration() to reinitialize the current configuration and
   * all its interfaces.
   */
  struct usb_host_config {
  	struct usb_config_descriptor	desc;
  
  	char *string;		/* iConfiguration string, if present */
  
  	/* List of any Interface Association Descriptors in this
  	 * configuration. */
  	struct usb_interface_assoc_descriptor *intf_assoc[USB_MAXIADS];
  
  	/* the interfaces associated with this configuration,
  	 * stored in no particular order */
  	struct usb_interface *interface[USB_MAXINTERFACES];
  
  	/* Interface information available even when this is not the
  	 * active configuration */
  	struct usb_interface_cache *intf_cache[USB_MAXINTERFACES];
  
  	unsigned char *extra;   /* Extra descriptors */
  	int extralen;
  };
  
  /* USB2.0 and USB3.0 device BOS descriptor set */
  struct usb_host_bos {
  	struct usb_bos_descriptor	*desc;
  
  	/* wireless cap descriptor is handled by wusb */
  	struct usb_ext_cap_descriptor	*ext_cap;
  	struct usb_ss_cap_descriptor	*ss_cap;
  	struct usb_ss_container_id_descriptor	*ss_id;
  };
  
  int __usb_get_extra_descriptor(char *buffer, unsigned size,
  	unsigned char type, void **ptr);
  #define usb_get_extra_descriptor(ifpoint, type, ptr) \
  				__usb_get_extra_descriptor((ifpoint)->extra, \
  				(ifpoint)->extralen, \
  				type, (void **)ptr)
  
  /* ----------------------------------------------------------------------- */
  
  /* USB device number allocation bitmap */
  struct usb_devmap {
  	unsigned long devicemap[128 / (8*sizeof(unsigned long))];
  };
  
  /*
   * Allocated per bus (tree of devices) we have:
   */
  struct usb_bus {
  	struct device *controller;	/* host/master side hardware */
  	int busnum;			/* Bus number (in order of reg) */
  	const char *bus_name;		/* stable id (PCI slot_name etc) */
  	u8 uses_dma;			/* Does the host controller use DMA? */
  	u8 uses_pio_for_control;	/*
  					 * Does the host controller use PIO
  					 * for control transfers?
  					 */
  	u8 otg_port;			/* 0, or number of OTG/HNP port */
  	unsigned is_b_host:1;		/* true during some HNP roleswitches */
  	unsigned b_hnp_enable:1;	/* OTG: did A-Host enable HNP? */
  	unsigned no_stop_on_short:1;    /*
  					 * Quirk: some controllers don't stop
  					 * the ep queue on a short transfer
  					 * with the URB_SHORT_NOT_OK flag set.
  					 */
  	unsigned no_sg_constraint:1;	/* no sg constraint */
  	unsigned sg_tablesize;		/* 0 or largest number of sg list entries */
  
  	int devnum_next;		/* Next open device number in
  					 * round-robin allocation */
  
  	struct usb_devmap devmap;	/* device address allocation map */
  	struct usb_device *root_hub;	/* Root hub */
  	struct usb_bus *hs_companion;	/* Companion EHCI bus, if any */
  	struct list_head bus_list;	/* list of busses */
  
  	struct mutex usb_address0_mutex; /* unaddressed device mutex */
  
  	int bandwidth_allocated;	/* on this bus: how much of the time
  					 * reserved for periodic (intr/iso)
  					 * requests is used, on average?
  					 * Units: microseconds/frame.
  					 * Limits: Full/low speed reserve 90%,
  					 * while high speed reserves 80%.
  					 */
  	int bandwidth_int_reqs;		/* number of Interrupt requests */
  	int bandwidth_isoc_reqs;	/* number of Isoc. requests */
  
  	unsigned resuming_ports;	/* bit array: resuming root-hub ports */
  
  #if defined(CONFIG_USB_MON) || defined(CONFIG_USB_MON_MODULE)
  	struct mon_bus *mon_bus;	/* non-null when associated */
  	int monitored;			/* non-zero when monitored */
  #endif
  };
  
  struct usb_dev_state;
  
  /* ----------------------------------------------------------------------- */
  
  struct usb_tt;
  
  enum usb_device_removable {
  	USB_DEVICE_REMOVABLE_UNKNOWN = 0,
  	USB_DEVICE_REMOVABLE,
  	USB_DEVICE_FIXED,
  };
  
  enum usb_port_connect_type {
  	USB_PORT_CONNECT_TYPE_UNKNOWN = 0,
  	USB_PORT_CONNECT_TYPE_HOT_PLUG,
  	USB_PORT_CONNECT_TYPE_HARD_WIRED,
  	USB_PORT_NOT_USED,
  };
  
  /*
   * USB 2.0 Link Power Management (LPM) parameters.
   */
  struct usb2_lpm_parameters {
  	/* Best effort service latency indicate how long the host will drive
  	 * resume on an exit from L1.
  	 */
  	unsigned int besl;
  
  	/* Timeout value in microseconds for the L1 inactivity (LPM) timer.
  	 * When the timer counts to zero, the parent hub will initiate a LPM
  	 * transition to L1.
  	 */
  	int timeout;
  };
  
  /*
   * USB 3.0 Link Power Management (LPM) parameters.
   *
   * PEL and SEL are USB 3.0 Link PM latencies for device-initiated LPM exit.
   * MEL is the USB 3.0 Link PM latency for host-initiated LPM exit.
   * All three are stored in nanoseconds.
   */
  struct usb3_lpm_parameters {
  	/*
  	 * Maximum exit latency (MEL) for the host to send a packet to the
  	 * device (either a Ping for isoc endpoints, or a data packet for
  	 * interrupt endpoints), the hubs to decode the packet, and for all hubs
  	 * in the path to transition the links to U0.
  	 */
  	unsigned int mel;
  	/*
  	 * Maximum exit latency for a device-initiated LPM transition to bring
  	 * all links into U0.  Abbreviated as "PEL" in section 9.4.12 of the USB
  	 * 3.0 spec, with no explanation of what "P" stands for.  "Path"?
  	 */
  	unsigned int pel;
  
  	/*
  	 * The System Exit Latency (SEL) includes PEL, and three other
  	 * latencies.  After a device initiates a U0 transition, it will take
  	 * some time from when the device sends the ERDY to when it will finally
  	 * receive the data packet.  Basically, SEL should be the worse-case
  	 * latency from when a device starts initiating a U0 transition to when
  	 * it will get data.
  	 */
  	unsigned int sel;
  	/*
  	 * The idle timeout value that is currently programmed into the parent
  	 * hub for this device.  When the timer counts to zero, the parent hub
  	 * will initiate an LPM transition to either U1 or U2.
  	 */
  	int timeout;
  };
  
  /**
   * struct usb_device - kernel's representation of a USB device
   * @devnum: device number; address on a USB bus
   * @devpath: device ID string for use in messages (e.g., /port/...)
   * @route: tree topology hex string for use with xHCI
   * @state: device state: configured, not attached, etc.
   * @speed: device speed: high/full/low (or error)
   * @tt: Transaction Translator info; used with low/full speed dev, highspeed hub
   * @ttport: device port on that tt hub
   * @toggle: one bit for each endpoint, with ([0] = IN, [1] = OUT) endpoints
   * @parent: our hub, unless we're the root
   * @bus: bus we're part of
   * @ep0: endpoint 0 data (default control pipe)
   * @dev: generic device interface
   * @descriptor: USB device descriptor
   * @bos: USB device BOS descriptor set
   * @config: all of the device's configs
   * @actconfig: the active configuration
   * @ep_in: array of IN endpoints
   * @ep_out: array of OUT endpoints
   * @rawdescriptors: raw descriptors for each config
   * @bus_mA: Current available from the bus
   * @portnum: parent port number (origin 1)
   * @level: number of USB hub ancestors
   * @can_submit: URBs may be submitted
   * @persist_enabled:  USB_PERSIST enabled for this device
   * @have_langid: whether string_langid is valid
   * @authorized: policy has said we can use it;
   *	(user space) policy determines if we authorize this device to be
   *	used or not. By default, wired USB devices are authorized.
   *	WUSB devices are not, until we authorize them from user space.
   *	FIXME -- complete doc
   * @authenticated: Crypto authentication passed
   * @wusb: device is Wireless USB
   * @lpm_capable: device supports LPM
   * @usb2_hw_lpm_capable: device can perform USB2 hardware LPM
   * @usb2_hw_lpm_besl_capable: device can perform USB2 hardware BESL LPM
   * @usb2_hw_lpm_enabled: USB2 hardware LPM is enabled
   * @usb2_hw_lpm_allowed: Userspace allows USB 2.0 LPM to be enabled
   * @usb3_lpm_enabled: USB3 hardware LPM enabled
   * @string_langid: language ID for strings
   * @product: iProduct string, if present (static)
   * @manufacturer: iManufacturer string, if present (static)
   * @serial: iSerialNumber string, if present (static)
   * @filelist: usbfs files that are open to this device
   * @maxchild: number of ports if hub
   * @quirks: quirks of the whole device
   * @urbnum: number of URBs submitted for the whole device
   * @active_duration: total time device is not suspended
   * @connect_time: time device was first connected
   * @do_remote_wakeup:  remote wakeup should be enabled
   * @reset_resume: needs reset instead of resume
   * @port_is_suspended: the upstream port is suspended (L2 or U3)
   * @wusb_dev: if this is a Wireless USB device, link to the WUSB
   *	specific data for the device.
   * @slot_id: Slot ID assigned by xHCI
   * @removable: Device can be physically removed from this port
   * @l1_params: best effor service latency for USB2 L1 LPM state, and L1 timeout.
   * @u1_params: exit latencies for USB3 U1 LPM state, and hub-initiated timeout.
   * @u2_params: exit latencies for USB3 U2 LPM state, and hub-initiated timeout.
   * @lpm_disable_count: Ref count used by usb_disable_lpm() and usb_enable_lpm()
   *	to keep track of the number of functions that require USB 3.0 Link Power
   *	Management to be disabled for this usb_device.  This count should only
   *	be manipulated by those functions, with the bandwidth_mutex is held.
   *
   * Notes:
   * Usbcore drivers should not set usbdev->state directly.  Instead use
   * usb_set_device_state().
   */
  struct usb_device {
  	int		devnum;
  	char		devpath[16];
  	u32		route;
  	enum usb_device_state	state;
  	enum usb_device_speed	speed;
  
  	struct usb_tt	*tt;
  	int		ttport;
  
  	unsigned int toggle[2];
  
  	struct usb_device *parent;
  	struct usb_bus *bus;
  	struct usb_host_endpoint ep0;
  
  	struct device dev;
  
  	struct usb_device_descriptor descriptor;
  	struct usb_host_bos *bos;
  	struct usb_host_config *config;
  
  	struct usb_host_config *actconfig;
  	struct usb_host_endpoint *ep_in[16];
  	struct usb_host_endpoint *ep_out[16];
  
  	char **rawdescriptors;
  
  	unsigned short bus_mA;
  	u8 portnum;
  	u8 level;
  
  	unsigned can_submit:1;
  	unsigned persist_enabled:1;
  	unsigned have_langid:1;
  	unsigned authorized:1;
  	unsigned authenticated:1;
  	unsigned wusb:1;
  	unsigned lpm_capable:1;
  	unsigned usb2_hw_lpm_capable:1;
  	unsigned usb2_hw_lpm_besl_capable:1;
  	unsigned usb2_hw_lpm_enabled:1;
  	unsigned usb2_hw_lpm_allowed:1;
  	unsigned usb3_lpm_enabled:1;
  	int string_langid;
  
  	/* static strings from the device */
  	char *product;
  	char *manufacturer;
  	char *serial;
  
  	struct list_head filelist;
  
  	int maxchild;
  
  	u32 quirks;
  	atomic_t urbnum;
  
  	unsigned long active_duration;
  
  #ifdef CONFIG_PM
  	unsigned long connect_time;
  
  	unsigned do_remote_wakeup:1;
  	unsigned reset_resume:1;
  	unsigned port_is_suspended:1;
  #endif
  	struct wusb_dev *wusb_dev;
  	int slot_id;
  	enum usb_device_removable removable;
  	struct usb2_lpm_parameters l1_params;
  	struct usb3_lpm_parameters u1_params;
  	struct usb3_lpm_parameters u2_params;
  	unsigned lpm_disable_count;
  };
  #define	to_usb_device(d) container_of(d, struct usb_device, dev)
  
  static inline struct usb_device *interface_to_usbdev(struct usb_interface *intf)
  {
  	return to_usb_device(intf->dev.parent);
  }
  
  extern struct usb_device *usb_get_dev(struct usb_device *dev);
  extern void usb_put_dev(struct usb_device *dev);
  extern struct usb_device *usb_hub_find_child(struct usb_device *hdev,
  	int port1);
  
  /**
   * usb_hub_for_each_child - iterate over all child devices on the hub
   * @hdev:  USB device belonging to the usb hub
   * @port1: portnum associated with child device
   * @child: child device pointer
   */
  #define usb_hub_for_each_child(hdev, port1, child) \
  	for (port1 = 1,	child =	usb_hub_find_child(hdev, port1); \
  			port1 <= hdev->maxchild; \
  			child = usb_hub_find_child(hdev, ++port1)) \
  		if (!child) continue; else
  
  /* USB device locking */
  #define usb_lock_device(udev)		device_lock(&(udev)->dev)
  #define usb_unlock_device(udev)		device_unlock(&(udev)->dev)
  #define usb_trylock_device(udev)	device_trylock(&(udev)->dev)
  extern int usb_lock_device_for_reset(struct usb_device *udev,
  				     const struct usb_interface *iface);
  
  /* USB port reset for device reinitialization */
  extern int usb_reset_device(struct usb_device *dev);
  extern void usb_queue_reset_device(struct usb_interface *dev);
  
  #ifdef CONFIG_ACPI
  extern int usb_acpi_set_power_state(struct usb_device *hdev, int index,
  	bool enable);
  extern bool usb_acpi_power_manageable(struct usb_device *hdev, int index);
  #else
  static inline int usb_acpi_set_power_state(struct usb_device *hdev, int index,
  	bool enable) { return 0; }
  static inline bool usb_acpi_power_manageable(struct usb_device *hdev, int index)
  	{ return true; }
  #endif
  
  /* USB autosuspend and autoresume */
  #ifdef CONFIG_PM
  extern void usb_enable_autosuspend(struct usb_device *udev);
  extern void usb_disable_autosuspend(struct usb_device *udev);
  
  extern int usb_autopm_get_interface(struct usb_interface *intf);
  extern void usb_autopm_put_interface(struct usb_interface *intf);
  extern int usb_autopm_get_interface_async(struct usb_interface *intf);
  extern void usb_autopm_put_interface_async(struct usb_interface *intf);
  extern void usb_autopm_get_interface_no_resume(struct usb_interface *intf);
  extern void usb_autopm_put_interface_no_suspend(struct usb_interface *intf);
  
  static inline void usb_mark_last_busy(struct usb_device *udev)
  {
  	pm_runtime_mark_last_busy(&udev->dev);
  }
  
  #else
  
  static inline int usb_enable_autosuspend(struct usb_device *udev)
  { return 0; }
  static inline int usb_disable_autosuspend(struct usb_device *udev)
  { return 0; }
  
  static inline int usb_autopm_get_interface(struct usb_interface *intf)
  { return 0; }
  static inline int usb_autopm_get_interface_async(struct usb_interface *intf)
  { return 0; }
  
  static inline void usb_autopm_put_interface(struct usb_interface *intf)
  { }
  static inline void usb_autopm_put_interface_async(struct usb_interface *intf)
  { }
  static inline void usb_autopm_get_interface_no_resume(
  		struct usb_interface *intf)
  { }
  static inline void usb_autopm_put_interface_no_suspend(
  		struct usb_interface *intf)
  { }
  static inline void usb_mark_last_busy(struct usb_device *udev)
  { }
  #endif
  
  extern int usb_disable_lpm(struct usb_device *udev);
  extern void usb_enable_lpm(struct usb_device *udev);
  /* Same as above, but these functions lock/unlock the bandwidth_mutex. */
  extern int usb_unlocked_disable_lpm(struct usb_device *udev);
  extern void usb_unlocked_enable_lpm(struct usb_device *udev);
  
  extern int usb_disable_ltm(struct usb_device *udev);
  extern void usb_enable_ltm(struct usb_device *udev);
  
  static inline bool usb_device_supports_ltm(struct usb_device *udev)
  {
  	if (udev->speed != USB_SPEED_SUPER || !udev->bos || !udev->bos->ss_cap)
  		return false;
  	return udev->bos->ss_cap->bmAttributes & USB_LTM_SUPPORT;
  }
  
  static inline bool usb_device_no_sg_constraint(struct usb_device *udev)
  {
  	return udev && udev->bus && udev->bus->no_sg_constraint;
  }
  
  
  /*-------------------------------------------------------------------------*/
  
  /* for drivers using iso endpoints */
  extern int usb_get_current_frame_number(struct usb_device *usb_dev);
  
  /* Sets up a group of bulk endpoints to support multiple stream IDs. */
  extern int usb_alloc_streams(struct usb_interface *interface,
  		struct usb_host_endpoint **eps, unsigned int num_eps,
  		unsigned int num_streams, gfp_t mem_flags);
  
  /* Reverts a group of bulk endpoints back to not using stream IDs. */
  extern int usb_free_streams(struct usb_interface *interface,
  		struct usb_host_endpoint **eps, unsigned int num_eps,
  		gfp_t mem_flags);
  
  /* used these for multi-interface device registration */
  extern int usb_driver_claim_interface(struct usb_driver *driver,
  			struct usb_interface *iface, void *priv);
  
  /**
   * usb_interface_claimed - returns true iff an interface is claimed
   * @iface: the interface being checked
   *
   * Return: %true (nonzero) iff the interface is claimed, else %false
   * (zero).
   *
   * Note:
   * Callers must own the driver model's usb bus readlock.  So driver
   * probe() entries don't need extra locking, but other call contexts
   * may need to explicitly claim that lock.
   *
   */
  static inline int usb_interface_claimed(struct usb_interface *iface)
  {
  	return (iface->dev.driver != NULL);
  }
  
  extern void usb_driver_release_interface(struct usb_driver *driver,
  			struct usb_interface *iface);
  const struct usb_device_id *usb_match_id(struct usb_interface *interface,
  					 const struct usb_device_id *id);
  extern int usb_match_one_id(struct usb_interface *interface,
  			    const struct usb_device_id *id);
  
  extern int usb_for_each_dev(void *data, int (*fn)(struct usb_device *, void *));
  extern struct usb_interface *usb_find_interface(struct usb_driver *drv,
  		int minor);
  extern struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
  		unsigned ifnum);
  extern struct usb_host_interface *usb_altnum_to_altsetting(
  		const struct usb_interface *intf, unsigned int altnum);
  extern struct usb_host_interface *usb_find_alt_setting(
  		struct usb_host_config *config,
  		unsigned int iface_num,
  		unsigned int alt_num);
  
  /* port claiming functions */
  int usb_hub_claim_port(struct usb_device *hdev, unsigned port1,
  		struct usb_dev_state *owner);
  int usb_hub_release_port(struct usb_device *hdev, unsigned port1,
  		struct usb_dev_state *owner);
  
  /**
   * usb_make_path - returns stable device path in the usb tree
   * @dev: the device whose path is being constructed
   * @buf: where to put the string
   * @size: how big is "buf"?
   *
   * Return: Length of the string (> 0) or negative if size was too small.
   *
   * Note:
   * This identifier is intended to be "stable", reflecting physical paths in
   * hardware such as physical bus addresses for host controllers or ports on
   * USB hubs.  That makes it stay the same until systems are physically
   * reconfigured, by re-cabling a tree of USB devices or by moving USB host
   * controllers.  Adding and removing devices, including virtual root hubs
   * in host controller driver modules, does not change these path identifiers;
   * neither does rebooting or re-enumerating.  These are more useful identifiers
   * than changeable ("unstable") ones like bus numbers or device addresses.
   *
   * With a partial exception for devices connected to USB 2.0 root hubs, these
   * identifiers are also predictable.  So long as the device tree isn't changed,
   * plugging any USB device into a given hub port always gives it the same path.
   * Because of the use of "companion" controllers, devices connected to ports on
   * USB 2.0 root hubs (EHCI host controllers) will get one path ID if they are
   * high speed, and a different one if they are full or low speed.
   */
  static inline int usb_make_path(struct usb_device *dev, char *buf, size_t size)
  {
  	int actual;
  	actual = snprintf(buf, size, "usb-%s-%s", dev->bus->bus_name,
  			  dev->devpath);
  	return (actual >= (int)size) ? -1 : actual;
  }
  
  /*-------------------------------------------------------------------------*/
  
  #define USB_DEVICE_ID_MATCH_DEVICE \
  		(USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT)
  #define USB_DEVICE_ID_MATCH_DEV_RANGE \
  		(USB_DEVICE_ID_MATCH_DEV_LO | USB_DEVICE_ID_MATCH_DEV_HI)
  #define USB_DEVICE_ID_MATCH_DEVICE_AND_VERSION \
  		(USB_DEVICE_ID_MATCH_DEVICE | USB_DEVICE_ID_MATCH_DEV_RANGE)
  #define USB_DEVICE_ID_MATCH_DEV_INFO \
  		(USB_DEVICE_ID_MATCH_DEV_CLASS | \
  		USB_DEVICE_ID_MATCH_DEV_SUBCLASS | \
  		USB_DEVICE_ID_MATCH_DEV_PROTOCOL)
  #define USB_DEVICE_ID_MATCH_INT_INFO \
  		(USB_DEVICE_ID_MATCH_INT_CLASS | \
  		USB_DEVICE_ID_MATCH_INT_SUBCLASS | \
  		USB_DEVICE_ID_MATCH_INT_PROTOCOL)
  
  /**
   * USB_DEVICE - macro used to describe a specific usb device
   * @vend: the 16 bit USB Vendor ID
   * @prod: the 16 bit USB Product ID
   *
   * This macro is used to create a struct usb_device_id that matches a
   * specific device.
   */
  #define USB_DEVICE(vend, prod) \
  	.match_flags = USB_DEVICE_ID_MATCH_DEVICE, \
  	.idVendor = (vend), \
  	.idProduct = (prod)
  /**
   * USB_DEVICE_VER - describe a specific usb device with a version range
   * @vend: the 16 bit USB Vendor ID
   * @prod: the 16 bit USB Product ID
   * @lo: the bcdDevice_lo value
   * @hi: the bcdDevice_hi value
   *
   * This macro is used to create a struct usb_device_id that matches a
   * specific device, with a version range.
   */
  #define USB_DEVICE_VER(vend, prod, lo, hi) \
  	.match_flags = USB_DEVICE_ID_MATCH_DEVICE_AND_VERSION, \
  	.idVendor = (vend), \
  	.idProduct = (prod), \
  	.bcdDevice_lo = (lo), \
  	.bcdDevice_hi = (hi)
  
  /**
   * USB_DEVICE_INTERFACE_CLASS - describe a usb device with a specific interface class
   * @vend: the 16 bit USB Vendor ID
   * @prod: the 16 bit USB Product ID
   * @cl: bInterfaceClass value
   *
   * This macro is used to create a struct usb_device_id that matches a
   * specific interface class of devices.
   */
  #define USB_DEVICE_INTERFACE_CLASS(vend, prod, cl) \
  	.match_flags = USB_DEVICE_ID_MATCH_DEVICE | \
  		       USB_DEVICE_ID_MATCH_INT_CLASS, \
  	.idVendor = (vend), \
  	.idProduct = (prod), \
  	.bInterfaceClass = (cl)
  
  /**
   * USB_DEVICE_INTERFACE_PROTOCOL - describe a usb device with a specific interface protocol
   * @vend: the 16 bit USB Vendor ID
   * @prod: the 16 bit USB Product ID
   * @pr: bInterfaceProtocol value
   *
   * This macro is used to create a struct usb_device_id that matches a
   * specific interface protocol of devices.
   */
  #define USB_DEVICE_INTERFACE_PROTOCOL(vend, prod, pr) \
  	.match_flags = USB_DEVICE_ID_MATCH_DEVICE | \
  		       USB_DEVICE_ID_MATCH_INT_PROTOCOL, \
  	.idVendor = (vend), \
  	.idProduct = (prod), \
  	.bInterfaceProtocol = (pr)
  
  /**
   * USB_DEVICE_INTERFACE_NUMBER - describe a usb device with a specific interface number
   * @vend: the 16 bit USB Vendor ID
   * @prod: the 16 bit USB Product ID
   * @num: bInterfaceNumber value
   *
   * This macro is used to create a struct usb_device_id that matches a
   * specific interface number of devices.
   */
  #define USB_DEVICE_INTERFACE_NUMBER(vend, prod, num) \
  	.match_flags = USB_DEVICE_ID_MATCH_DEVICE | \
  		       USB_DEVICE_ID_MATCH_INT_NUMBER, \
  	.idVendor = (vend), \
  	.idProduct = (prod), \
  	.bInterfaceNumber = (num)
  
  /**
   * USB_DEVICE_INFO - macro used to describe a class of usb devices
   * @cl: bDeviceClass value
   * @sc: bDeviceSubClass value
   * @pr: bDeviceProtocol value
   *
   * This macro is used to create a struct usb_device_id that matches a
   * specific class of devices.
   */
  #define USB_DEVICE_INFO(cl, sc, pr) \
  	.match_flags = USB_DEVICE_ID_MATCH_DEV_INFO, \
  	.bDeviceClass = (cl), \
  	.bDeviceSubClass = (sc), \
  	.bDeviceProtocol = (pr)
  
  /**
   * USB_INTERFACE_INFO - macro used to describe a class of usb interfaces
   * @cl: bInterfaceClass value
   * @sc: bInterfaceSubClass value
   * @pr: bInterfaceProtocol value
   *
   * This macro is used to create a struct usb_device_id that matches a
   * specific class of interfaces.
   */
  #define USB_INTERFACE_INFO(cl, sc, pr) \
  	.match_flags = USB_DEVICE_ID_MATCH_INT_INFO, \
  	.bInterfaceClass = (cl), \
  	.bInterfaceSubClass = (sc), \
  	.bInterfaceProtocol = (pr)
  
  /**
   * USB_DEVICE_AND_INTERFACE_INFO - describe a specific usb device with a class of usb interfaces
   * @vend: the 16 bit USB Vendor ID
   * @prod: the 16 bit USB Product ID
   * @cl: bInterfaceClass value
   * @sc: bInterfaceSubClass value
   * @pr: bInterfaceProtocol value
   *
   * This macro is used to create a struct usb_device_id that matches a
   * specific device with a specific class of interfaces.
   *
   * This is especially useful when explicitly matching devices that have
   * vendor specific bDeviceClass values, but standards-compliant interfaces.
   */
  #define USB_DEVICE_AND_INTERFACE_INFO(vend, prod, cl, sc, pr) \
  	.match_flags = USB_DEVICE_ID_MATCH_INT_INFO \
  		| USB_DEVICE_ID_MATCH_DEVICE, \
  	.idVendor = (vend), \
  	.idProduct = (prod), \
  	.bInterfaceClass = (cl), \
  	.bInterfaceSubClass = (sc), \
  	.bInterfaceProtocol = (pr)
  
  /**
   * USB_VENDOR_AND_INTERFACE_INFO - describe a specific usb vendor with a class of usb interfaces
   * @vend: the 16 bit USB Vendor ID
   * @cl: bInterfaceClass value
   * @sc: bInterfaceSubClass value
   * @pr: bInterfaceProtocol value
   *
   * This macro is used to create a struct usb_device_id that matches a
   * specific vendor with a specific class of interfaces.
   *
   * This is especially useful when explicitly matching devices that have
   * vendor specific bDeviceClass values, but standards-compliant interfaces.
   */
  #define USB_VENDOR_AND_INTERFACE_INFO(vend, cl, sc, pr) \
  	.match_flags = USB_DEVICE_ID_MATCH_INT_INFO \
  		| USB_DEVICE_ID_MATCH_VENDOR, \
  	.idVendor = (vend), \
  	.bInterfaceClass = (cl), \
  	.bInterfaceSubClass = (sc), \
  	.bInterfaceProtocol = (pr)
  
  /* ----------------------------------------------------------------------- */
  
  /* Stuff for dynamic usb ids */
  struct usb_dynids {
  	spinlock_t lock;
  	struct list_head list;
  };
  
  struct usb_dynid {
  	struct list_head node;
  	struct usb_device_id id;
  };
  
  extern 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);
  
  extern ssize_t usb_show_dynids(struct usb_dynids *dynids, char *buf);
  
  /**
   * struct usbdrv_wrap - wrapper for driver-model structure
   * @driver: The driver-model core driver structure.
   * @for_devices: Non-zero for device drivers, 0 for interface drivers.
   */
  struct usbdrv_wrap {
  	struct device_driver driver;
  	int for_devices;
  };
  
  /**
   * struct usb_driver - identifies USB interface driver to usbcore
   * @name: The driver name should be unique among USB drivers,
   *	and should normally be the same as the module name.
   * @probe: Called to see if the driver is willing to manage a particular
   *	interface on a device.  If it is, probe returns zero and uses
   *	usb_set_intfdata() to associate driver-specific data with the
   *	interface.  It may also use usb_set_interface() to specify the
   *	appropriate altsetting.  If unwilling to manage the interface,
   *	return -ENODEV, if genuine IO errors occurred, an appropriate
   *	negative errno value.
   * @disconnect: Called when the interface is no longer accessible, usually
   *	because its device has been (or is being) disconnected or the
   *	driver module is being unloaded.
   * @unlocked_ioctl: Used for drivers that want to talk to userspace through
   *	the "usbfs" filesystem.  This lets devices provide ways to
   *	expose information to user space regardless of where they
   *	do (or don't) show up otherwise in the filesystem.
   * @suspend: Called when the device is going to be suspended by the
   *	system either from system sleep or runtime suspend context. The
   *	return value will be ignored in system sleep context, so do NOT
   *	try to continue using the device if suspend fails in this case.
   *	Instead, let the resume or reset-resume routine recover from
   *	the failure.
   * @resume: Called when the device is being resumed by the system.
   * @reset_resume: Called when the suspended device has been reset instead
   *	of being resumed.
   * @pre_reset: Called by usb_reset_device() when the device is about to be
   *	reset.  This routine must not return until the driver has no active
   *	URBs for the device, and no more URBs may be submitted until the
   *	post_reset method is called.
   * @post_reset: Called by usb_reset_device() after the device
   *	has been reset
   * @id_table: USB drivers use ID table to support hotplugging.
   *	Export this with MODULE_DEVICE_TABLE(usb,...).  This must be set
   *	or your driver's probe function will never get called.
   * @dynids: used internally to hold the list of dynamically added device
   *	ids for this driver.
   * @drvwrap: Driver-model core structure wrapper.
   * @no_dynamic_id: if set to 1, the USB core will not allow dynamic ids to be
   *	added to this driver by preventing the sysfs file from being created.
   * @supports_autosuspend: if set to 0, the USB core will not allow autosuspend
   *	for interfaces bound to this driver.
   * @soft_unbind: if set to 1, the USB core will not kill URBs and disable
   *	endpoints before calling the driver's disconnect method.
   * @disable_hub_initiated_lpm: if set to 0, the USB core will not allow hubs
   *	to initiate lower power link state transitions when an idle timeout
   *	occurs.  Device-initiated USB 3.0 link PM will still be allowed.
   *
   * USB interface drivers must provide a name, probe() and disconnect()
   * methods, and an id_table.  Other driver fields are optional.
   *
   * The id_table is used in hotplugging.  It holds a set of descriptors,
   * and specialized data may be associated with each entry.  That table
   * is used by both user and kernel mode hotplugging support.
   *
   * The probe() and disconnect() methods are called in a context where
   * they can sleep, but they should avoid abusing the privilege.  Most
   * work to connect to a device should be done when the device is opened,
   * and undone at the last close.  The disconnect code needs to address
   * concurrency issues with respect to open() and close() methods, as
   * well as forcing all pending I/O requests to complete (by unlinking
   * them as necessary, and blocking until the unlinks complete).
   */
  struct usb_driver {
  	const char *name;
  
  	int (*probe) (struct usb_interface *intf,
  		      const struct usb_device_id *id);
  
  	void (*disconnect) (struct usb_interface *intf);
  
  	int (*unlocked_ioctl) (struct usb_interface *intf, unsigned int code,
  			void *buf);
  
  	int (*suspend) (struct usb_interface *intf, pm_message_t message);
  	int (*resume) (struct usb_interface *intf);
  	int (*reset_resume)(struct usb_interface *intf);
  
  	int (*pre_reset)(struct usb_interface *intf);
  	int (*post_reset)(struct usb_interface *intf);
  
  	const struct usb_device_id *id_table;
  
  	struct usb_dynids dynids;
  	struct usbdrv_wrap drvwrap;
  	unsigned int no_dynamic_id:1;
  	unsigned int supports_autosuspend:1;
  	unsigned int disable_hub_initiated_lpm:1;
  	unsigned int soft_unbind:1;
  };
  #define	to_usb_driver(d) container_of(d, struct usb_driver, drvwrap.driver)
  
  /**
   * struct usb_device_driver - identifies USB device driver to usbcore
   * @name: The driver name should be unique among USB drivers,
   *	and should normally be the same as the module name.
   * @probe: Called to see if the driver is willing to manage a particular
   *	device.  If it is, probe returns zero and uses dev_set_drvdata()
   *	to associate driver-specific data with the device.  If unwilling
   *	to manage the device, return a negative errno value.
   * @disconnect: Called when the device is no longer accessible, usually
   *	because it has been (or is being) disconnected or the driver's
   *	module is being unloaded.
   * @suspend: Called when the device is going to be suspended by the system.
   * @resume: Called when the device is being resumed by the system.
   * @drvwrap: Driver-model core structure wrapper.
   * @supports_autosuspend: if set to 0, the USB core will not allow autosuspend
   *	for devices bound to this driver.
   *
   * USB drivers must provide all the fields listed above except drvwrap.
   */
  struct usb_device_driver {
  	const char *name;
  
  	int (*probe) (struct usb_device *udev);
  	void (*disconnect) (struct usb_device *udev);
  
  	int (*suspend) (struct usb_device *udev, pm_message_t message);
  	int (*resume) (struct usb_device *udev, pm_message_t message);
  	struct usbdrv_wrap drvwrap;
  	unsigned int supports_autosuspend:1;
  };
  #define	to_usb_device_driver(d) container_of(d, struct usb_device_driver, \
  		drvwrap.driver)
  
  extern struct bus_type usb_bus_type;
  
  /**
   * struct usb_class_driver - identifies a USB driver that wants to use the USB major number
   * @name: the usb class device name for this driver.  Will show up in sysfs.
   * @devnode: Callback to provide a naming hint for a possible
   *	device node to create.
   * @fops: pointer to the struct file_operations of this driver.
   * @minor_base: the start of the minor range for this driver.
   *
   * This structure is used for the usb_register_dev() and
   * usb_unregister_dev() functions, to consolidate a number of the
   * parameters used for them.
   */
  struct usb_class_driver {
  	char *name;
  	char *(*devnode)(struct device *dev, umode_t *mode);
  	const struct file_operations *fops;
  	int minor_base;
  };
  
  /*
   * use these in module_init()/module_exit()
   * and don't forget MODULE_DEVICE_TABLE(usb, ...)
   */
  extern int usb_register_driver(struct usb_driver *, struct module *,
  			       const char *);
  
  /* use a define to avoid include chaining to get THIS_MODULE & friends */
  #define usb_register(driver) \
  	usb_register_driver(driver, THIS_MODULE, KBUILD_MODNAME)
  
  extern void usb_deregister(struct usb_driver *);
  
  /**
   * module_usb_driver() - Helper macro for registering a USB driver
   * @__usb_driver: usb_driver struct
   *
   * Helper macro for USB drivers which do not do anything special in module
   * init/exit. This eliminates a lot of boilerplate. Each module may only
   * use this macro once, and calling it replaces module_init() and module_exit()
   */
  #define module_usb_driver(__usb_driver) \
  	module_driver(__usb_driver, usb_register, \
  		       usb_deregister)
  
  extern int usb_register_device_driver(struct usb_device_driver *,
  			struct module *);
  extern void usb_deregister_device_driver(struct usb_device_driver *);
  
  extern int usb_register_dev(struct usb_interface *intf,
  			    struct usb_class_driver *class_driver);
  extern void usb_deregister_dev(struct usb_interface *intf,
  			       struct usb_class_driver *class_driver);
  
  extern int usb_disabled(void);
  
  /* ----------------------------------------------------------------------- */
  
  /*
   * URB support, for asynchronous request completions
   */
  
  /*
   * urb->transfer_flags:
   *
   * Note: URB_DIR_IN/OUT is automatically set in usb_submit_urb().
   */
  #define URB_SHORT_NOT_OK	0x0001	/* report short reads as errors */
  #define URB_ISO_ASAP		0x0002	/* iso-only; use the first unexpired
  					 * slot in the schedule */
  #define URB_NO_TRANSFER_DMA_MAP	0x0004	/* urb->transfer_dma valid on submit */
  #define URB_NO_FSBR		0x0020	/* UHCI-specific */
  #define URB_ZERO_PACKET		0x0040	/* Finish bulk OUT with short packet */
  #define URB_NO_INTERRUPT	0x0080	/* HINT: no non-error interrupt
  					 * needed */
  #define URB_FREE_BUFFER		0x0100	/* Free transfer buffer with the URB */
  
  /* The following flags are used internally by usbcore and HCDs */
  #define URB_DIR_IN		0x0200	/* Transfer from device to host */
  #define URB_DIR_OUT		0
  #define URB_DIR_MASK		URB_DIR_IN
  
  #define URB_DMA_MAP_SINGLE	0x00010000	/* Non-scatter-gather mapping */
  #define URB_DMA_MAP_PAGE	0x00020000	/* HCD-unsupported S-G */
  #define URB_DMA_MAP_SG		0x00040000	/* HCD-supported S-G */
  #define URB_MAP_LOCAL		0x00080000	/* HCD-local-memory mapping */
  #define URB_SETUP_MAP_SINGLE	0x00100000	/* Setup packet DMA mapped */
  #define URB_SETUP_MAP_LOCAL	0x00200000	/* HCD-local setup packet */
  #define URB_DMA_SG_COMBINED	0x00400000	/* S-G entries were combined */
  #define URB_ALIGNED_TEMP_BUFFER	0x00800000	/* Temp buffer was alloc'd */
  
  struct usb_iso_packet_descriptor {
  	unsigned int offset;
  	unsigned int length;		/* expected length */
  	unsigned int actual_length;
  	int status;
  };
  
  struct urb;
  
  struct usb_anchor {
  	struct list_head urb_list;
  	wait_queue_head_t wait;
  	spinlock_t lock;
  	atomic_t suspend_wakeups;
  	unsigned int poisoned:1;
  };
  
  static inline void init_usb_anchor(struct usb_anchor *anchor)
  {
  	memset(anchor, 0, sizeof(*anchor));
  	INIT_LIST_HEAD(&anchor->urb_list);
  	init_waitqueue_head(&anchor->wait);
  	spin_lock_init(&anchor->lock);
  }
  
  typedef void (*usb_complete_t)(struct urb *);
  
  /**
   * struct urb - USB Request Block
   * @urb_list: For use by current owner of the URB.
   * @anchor_list: membership in the list of an anchor
   * @anchor: to anchor URBs to a common mooring
   * @ep: Points to the endpoint's data structure.  Will eventually
   *	replace @pipe.
   * @pipe: Holds endpoint number, direction, type, and more.
   *	Create these values with the eight macros available;
   *	usb_{snd,rcv}TYPEpipe(dev,endpoint), where the TYPE is "ctrl"
   *	(control), "bulk", "int" (interrupt), or "iso" (isochronous).
   *	For example usb_sndbulkpipe() or usb_rcvintpipe().  Endpoint
   *	numbers range from zero to fifteen.  Note that "in" endpoint two
   *	is a different endpoint (and pipe) from "out" endpoint two.
   *	The current configuration controls the existence, type, and
   *	maximum packet size of any given endpoint.
   * @stream_id: the endpoint's stream ID for bulk streams
   * @dev: Identifies the USB device to perform the request.
   * @status: This is read in non-iso completion functions to get the
   *	status of the particular request.  ISO requests only use it
   *	to tell whether the URB was unlinked; detailed status for
   *	each frame is in the fields of the iso_frame-desc.
   * @transfer_flags: A variety of flags may be used to affect how URB
   *	submission, unlinking, or operation are handled.  Different
   *	kinds of URB can use different flags.
   * @transfer_buffer:  This identifies the buffer to (or from) which the I/O
   *	request will be performed unless URB_NO_TRANSFER_DMA_MAP is set
   *	(however, do not leave garbage in transfer_buffer even then).
   *	This buffer must be suitable for DMA; allocate it with
   *	kmalloc() or equivalent.  For transfers to "in" endpoints, contents
   *	of this buffer will be modified.  This buffer is used for the data
   *	stage of control transfers.
   * @transfer_dma: When transfer_flags includes URB_NO_TRANSFER_DMA_MAP,
   *	the device driver is saying that it provided this DMA address,
   *	which the host controller driver should use in preference to the
   *	transfer_buffer.
   * @sg: scatter gather buffer list, the buffer size of each element in
   * 	the list (except the last) must be divisible by the endpoint's
   * 	max packet size if no_sg_constraint isn't set in 'struct usb_bus'
   * @num_mapped_sgs: (internal) number of mapped sg entries
   * @num_sgs: number of entries in the sg list
   * @transfer_buffer_length: How big is transfer_buffer.  The transfer may
   *	be broken up into chunks according to the current maximum packet
   *	size for the endpoint, which is a function of the configuration
   *	and is encoded in the pipe.  When the length is zero, neither
   *	transfer_buffer nor transfer_dma is used.
   * @actual_length: This is read in non-iso completion functions, and
   *	it tells how many bytes (out of transfer_buffer_length) were
   *	transferred.  It will normally be the same as requested, unless
   *	either an error was reported or a short read was performed.
   *	The URB_SHORT_NOT_OK transfer flag may be used to make such
   *	short reads be reported as errors.
   * @setup_packet: Only used for control transfers, this points to eight bytes
   *	of setup data.  Control transfers always start by sending this data
   *	to the device.  Then transfer_buffer is read or written, if needed.
   * @setup_dma: DMA pointer for the setup packet.  The caller must not use
   *	this field; setup_packet must point to a valid buffer.
   * @start_frame: Returns the initial frame for isochronous transfers.
   * @number_of_packets: Lists the number of ISO transfer buffers.
   * @interval: Specifies the polling interval for interrupt or isochronous
   *	transfers.  The units are frames (milliseconds) for full and low
   *	speed devices, and microframes (1/8 millisecond) for highspeed
   *	and SuperSpeed devices.
   * @error_count: Returns the number of ISO transfers that reported errors.
   * @context: For use in completion functions.  This normally points to
   *	request-specific driver context.
   * @complete: Completion handler. This URB is passed as the parameter to the
   *	completion function.  The completion function may then do what
   *	it likes with the URB, including resubmitting or freeing it.
   * @iso_frame_desc: Used to provide arrays of ISO transfer buffers and to
   *	collect the transfer status for each buffer.
   *
   * This structure identifies USB transfer requests.  URBs must be allocated by
   * calling usb_alloc_urb() and freed with a call to usb_free_urb().
   * Initialization may be done using various usb_fill_*_urb() functions.  URBs
   * are submitted using usb_submit_urb(), and pending requests may be canceled
   * using usb_unlink_urb() or usb_kill_urb().
   *
   * Data Transfer Buffers:
   *
   * Normally drivers provide I/O buffers allocated with kmalloc() or otherwise
   * taken from the general page pool.  That is provided by transfer_buffer
   * (control requests also use setup_packet), and host controller drivers
   * perform a dma mapping (and unmapping) for each buffer transferred.  Those
   * mapping operations can be expensive on some platforms (perhaps using a dma
   * bounce buffer or talking to an IOMMU),
   * although they're cheap on commodity x86 and ppc hardware.
   *
   * Alternatively, drivers may pass the URB_NO_TRANSFER_DMA_MAP transfer flag,
   * which tells the host controller driver that no such mapping is needed for
   * the transfer_buffer since
   * the device driver is DMA-aware.  For example, a device driver might
   * allocate a DMA buffer with usb_alloc_coherent() or call usb_buffer_map().
   * When this transfer flag is provided, host controller drivers will
   * attempt to use the dma address found in the transfer_dma
   * field rather than determining a dma address themselves.
   *
   * Note that transfer_buffer must still be set if the controller
   * does not support DMA (as indicated by bus.uses_dma) and when talking
   * to root hub. If you have to trasfer between highmem zone and the device
   * on such controller, create a bounce buffer or bail out with an error.
   * If transfer_buffer cannot be set (is in highmem) and the controller is DMA
   * capable, assign NULL to it, so that usbmon knows not to use the value.
   * The setup_packet must always be set, so it cannot be located in highmem.
   *
   * Initialization:
   *
   * All URBs submitted must initialize the dev, pipe, transfer_flags (may be
   * zero), and complete fields.  All URBs must also initialize
   * transfer_buffer and transfer_buffer_length.  They may provide the
   * URB_SHORT_NOT_OK transfer flag, indicating that short reads are
   * to be treated as errors; that flag is invalid for write requests.
   *
   * Bulk URBs may
   * use the URB_ZERO_PACKET transfer flag, indicating that bulk OUT transfers
   * should always terminate with a short packet, even if it means adding an
   * extra zero length packet.
   *
   * Control URBs must provide a valid pointer in the setup_packet field.
   * Unlike the transfer_buffer, the setup_packet may not be mapped for DMA
   * beforehand.
   *
   * Interrupt URBs must provide an interval, saying how often (in milliseconds
   * or, for highspeed devices, 125 microsecond units)
   * to poll for transfers.  After the URB has been submitted, the interval
   * field reflects how the transfer was actually scheduled.
   * The polling interval may be more frequent than requested.
   * For example, some controllers have a maximum interval of 32 milliseconds,
   * while others support intervals of up to 1024 milliseconds.
   * Isochronous URBs also have transfer intervals.  (Note that for isochronous
   * endpoints, as well as high speed interrupt endpoints, the encoding of
   * the transfer interval in the endpoint descriptor is logarithmic.
   * Device drivers must convert that value to linear units themselves.)
   *
   * If an isochronous endpoint queue isn't already running, the host
   * controller will schedule a new URB to start as soon as bandwidth
   * utilization allows.  If the queue is running then a new URB will be
   * scheduled to start in the first transfer slot following the end of the
   * preceding URB, if that slot has not already expired.  If the slot has
   * expired (which can happen when IRQ delivery is delayed for a long time),
   * the scheduling behavior depends on the URB_ISO_ASAP flag.  If the flag
   * is clear then the URB will be scheduled to start in the expired slot,
   * implying that some of its packets will not be transferred; if the flag
   * is set then the URB will be scheduled in the first unexpired slot,
   * breaking the queue's synchronization.  Upon URB completion, the
   * start_frame field will be set to the (micro)frame number in which the
   * transfer was scheduled.  Ranges for frame counter values are HC-specific
   * and can go from as low as 256 to as high as 65536 frames.
   *
   * Isochronous URBs have a different data transfer model, in part because
   * the quality of service is only "best effort".  Callers provide specially
   * allocated URBs, with number_of_packets worth of iso_frame_desc structures
   * at the end.  Each such packet is an individual ISO transfer.  Isochronous
   * URBs are normally queued, submitted by drivers to arrange that
   * transfers are at least double buffered, and then explicitly resubmitted
   * in completion handlers, so
   * that data (such as audio or video) streams at as constant a rate as the
   * host controller scheduler can support.
   *
   * Completion Callbacks:
   *
   * The completion callback is made in_interrupt(), and one of the first
   * things that a completion handler should do is check the status field.
   * The status field is provided for all URBs.  It is used to report
   * unlinked URBs, and status for all non-ISO transfers.  It should not
   * be examined before the URB is returned to the completion handler.
   *
   * The context field is normally used to link URBs back to the relevant
   * driver or request state.
   *
   * When the completion callback is invoked for non-isochronous URBs, the
   * actual_length field tells how many bytes were transferred.  This field
   * is updated even when the URB terminated with an error or was unlinked.
   *
   * ISO transfer status is reported in the status and actual_length fields
   * of the iso_frame_desc array, and the number of errors is reported in
   * error_count.  Completion callbacks for ISO transfers will normally
   * (re)submit URBs to ensure a constant transfer rate.
   *
   * Note that even fields marked "public" should not be touched by the driver
   * when the urb is owned by the hcd, that is, since the call to
   * usb_submit_urb() till the entry into the completion routine.
   */
  struct urb {
  	/* private: usb core and host controller only fields in the urb */
  	struct kref kref;		/* reference count of the URB */
  	void *hcpriv;			/* private data for host controller */
  	atomic_t use_count;		/* concurrent submissions counter */
  	atomic_t reject;		/* submissions will fail */
  	int unlinked;			/* unlink error code */
  
  	/* public: documented fields in the urb that can be used by drivers */
  	struct list_head urb_list;	/* list head for use by the urb's
  					 * current owner */
  	struct list_head anchor_list;	/* the URB may be anchored */
  	struct usb_anchor *anchor;
  	struct usb_device *dev;		/* (in) pointer to associated device */
  	struct usb_host_endpoint *ep;	/* (internal) pointer to endpoint */
  	unsigned int pipe;		/* (in) pipe information */
  	unsigned int stream_id;		/* (in) stream ID */
  	int status;			/* (return) non-ISO status */
  	unsigned int transfer_flags;	/* (in) URB_SHORT_NOT_OK | ...*/
  	void *transfer_buffer;		/* (in) associated data buffer */
  	dma_addr_t transfer_dma;	/* (in) dma addr for transfer_buffer */
  	struct scatterlist *sg;		/* (in) scatter gather buffer list */
  	int num_mapped_sgs;		/* (internal) mapped sg entries */
  	int num_sgs;			/* (in) number of entries in the sg list */
  	u32 transfer_buffer_length;	/* (in) data buffer length */
  	u32 actual_length;		/* (return) actual transfer length */
  	unsigned char *setup_packet;	/* (in) setup packet (control only) */
  	dma_addr_t setup_dma;		/* (in) dma addr for setup_packet */
  	int start_frame;		/* (modify) start frame (ISO) */
  	int number_of_packets;		/* (in) number of ISO packets */
  	int interval;			/* (modify) transfer interval
  					 * (INT/ISO) */
  	int error_count;		/* (return) number of ISO errors */
  	void *context;			/* (in) context for completion */
  	usb_complete_t complete;	/* (in) completion routine */
  	struct usb_iso_packet_descriptor iso_frame_desc[0];
  					/* (in) ISO ONLY */
  };
  
  /* ----------------------------------------------------------------------- */
  
  /**
   * usb_fill_control_urb - initializes a control urb
   * @urb: pointer to the urb to initialize.
   * @dev: pointer to the struct usb_device for this urb.
   * @pipe: the endpoint pipe
   * @setup_packet: pointer to the setup_packet buffer
   * @transfer_buffer: pointer to the transfer buffer
   * @buffer_length: length of the transfer buffer
   * @complete_fn: pointer to the usb_complete_t function
   * @context: what to set the urb context to.
   *
   * Initializes a control urb with the proper information needed to submit
   * it to a device.
   */
  static inline void usb_fill_control_urb(struct urb *urb,
  					struct usb_device *dev,
  					unsigned int pipe,
  					unsigned char *setup_packet,
  					void *transfer_buffer,
  					int buffer_length,
  					usb_complete_t complete_fn,
  					void *context)
  {
  	urb->dev = dev;
  	urb->pipe = pipe;
  	urb->setup_packet = setup_packet;
  	urb->transfer_buffer = transfer_buffer;
  	urb->transfer_buffer_length = buffer_length;
  	urb->complete = complete_fn;
  	urb->context = context;
  }
  
  /**
   * usb_fill_bulk_urb - macro to help initialize a bulk urb
   * @urb: pointer to the urb to initialize.
   * @dev: pointer to the struct usb_device for this urb.
   * @pipe: the endpoint pipe
   * @transfer_buffer: pointer to the transfer buffer
   * @buffer_length: length of the transfer buffer
   * @complete_fn: pointer to the usb_complete_t function
   * @context: what to set the urb context to.
   *
   * Initializes a bulk urb with the proper information needed to submit it
   * to a device.
   */
  static inline void usb_fill_bulk_urb(struct urb *urb,
  				     struct usb_device *dev,
  				     unsigned int pipe,
  				     void *transfer_buffer,
  				     int buffer_length,
  				     usb_complete_t complete_fn,
  				     void *context)
  {
  	urb->dev = dev;
  	urb->pipe = pipe;
  	urb->transfer_buffer = transfer_buffer;
  	urb->transfer_buffer_length = buffer_length;
  	urb->complete = complete_fn;
  	urb->context = context;
  }
  
  /**
   * usb_fill_int_urb - macro to help initialize a interrupt urb
   * @urb: pointer to the urb to initialize.
   * @dev: pointer to the struct usb_device for this urb.
   * @pipe: the endpoint pipe
   * @transfer_buffer: pointer to the transfer buffer
   * @buffer_length: length of the transfer buffer
   * @complete_fn: pointer to the usb_complete_t function
   * @context: what to set the urb context to.
   * @interval: what to set the urb interval to, encoded like
   *	the endpoint descriptor's bInterval value.
   *
   * Initializes a interrupt urb with the proper information needed to submit
   * it to a device.
   *
   * Note that High Speed and SuperSpeed interrupt endpoints use a logarithmic
   * encoding of the endpoint interval, and express polling intervals in
   * microframes (eight per millisecond) rather than in frames (one per
   * millisecond).
   *
   * Wireless USB also uses the logarithmic encoding, but specifies it in units of
   * 128us instead of 125us.  For Wireless USB devices, the interval is passed
   * through to the host controller, rather than being translated into microframe
   * units.
   */
  static inline void usb_fill_int_urb(struct urb *urb,
  				    struct usb_device *dev,
  				    unsigned int pipe,
  				    void *transfer_buffer,
  				    int buffer_length,
  				    usb_complete_t complete_fn,
  				    void *context,
  				    int interval)
  {
  	urb->dev = dev;
  	urb->pipe = pipe;
  	urb->transfer_buffer = transfer_buffer;
  	urb->transfer_buffer_length = buffer_length;
  	urb->complete = complete_fn;
  	urb->context = context;
  
  	if (dev->speed == USB_SPEED_HIGH || dev->speed == USB_SPEED_SUPER) {
  		/* make sure interval is within allowed range */
  		interval = clamp(interval, 1, 16);
  
  		urb->interval = 1 << (interval - 1);
  	} else {
  		urb->interval = interval;
  	}
  
  	urb->start_frame = -1;
  }
  
  extern void usb_init_urb(struct urb *urb);
  extern struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags);
  extern void usb_free_urb(struct urb *urb);
  #define usb_put_urb usb_free_urb
  extern struct urb *usb_get_urb(struct urb *urb);
  extern int usb_submit_urb(struct urb *urb, gfp_t mem_flags);
  extern int usb_unlink_urb(struct urb *urb);
  extern void usb_kill_urb(struct urb *urb);
  extern void usb_poison_urb(struct urb *urb);
  extern void usb_unpoison_urb(struct urb *urb);
  extern void usb_block_urb(struct urb *urb);
  extern void usb_kill_anchored_urbs(struct usb_anchor *anchor);
  extern void usb_poison_anchored_urbs(struct usb_anchor *anchor);
  extern void usb_unpoison_anchored_urbs(struct usb_anchor *anchor);
  extern void usb_unlink_anchored_urbs(struct usb_anchor *anchor);
  extern void usb_anchor_suspend_wakeups(struct usb_anchor *anchor);
  extern void usb_anchor_resume_wakeups(struct usb_anchor *anchor);
  extern void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor);
  extern void usb_unanchor_urb(struct urb *urb);
  extern int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
  					 unsigned int timeout);
  extern struct urb *usb_get_from_anchor(struct usb_anchor *anchor);
  extern void usb_scuttle_anchored_urbs(struct usb_anchor *anchor);
  extern int usb_anchor_empty(struct usb_anchor *anchor);
  
  #define usb_unblock_urb	usb_unpoison_urb
  
  /**
   * usb_urb_dir_in - check if an URB describes an IN transfer
   * @urb: URB to be checked
   *
   * Return: 1 if @urb describes an IN transfer (device-to-host),
   * otherwise 0.
   */
  static inline int usb_urb_dir_in(struct urb *urb)
  {
  	return (urb->transfer_flags & URB_DIR_MASK) == URB_DIR_IN;
  }
  
  /**
   * usb_urb_dir_out - check if an URB describes an OUT transfer
   * @urb: URB to be checked
   *
   * Return: 1 if @urb describes an OUT transfer (host-to-device),
   * otherwise 0.
   */
  static inline int usb_urb_dir_out(struct urb *urb)
  {
  	return (urb->transfer_flags & URB_DIR_MASK) == URB_DIR_OUT;
  }
  
  void *usb_alloc_coherent(struct usb_device *dev, size_t size,
  	gfp_t mem_flags, dma_addr_t *dma);
  void usb_free_coherent(struct usb_device *dev, size_t size,
  	void *addr, dma_addr_t dma);
  
  #if 0
  struct urb *usb_buffer_map(struct urb *urb);
  void usb_buffer_dmasync(struct urb *urb);
  void usb_buffer_unmap(struct urb *urb);
  #endif
  
  struct scatterlist;
  int usb_buffer_map_sg(const struct usb_device *dev, int is_in,
  		      struct scatterlist *sg, int nents);
  #if 0
  void usb_buffer_dmasync_sg(const struct usb_device *dev, int is_in,
  			   struct scatterlist *sg, int n_hw_ents);
  #endif
  void usb_buffer_unmap_sg(const struct usb_device *dev, int is_in,
  			 struct scatterlist *sg, int n_hw_ents);
  
  /*-------------------------------------------------------------------*
   *                         SYNCHRONOUS CALL SUPPORT                  *
   *-------------------------------------------------------------------*/
  
  extern int usb_control_msg(struct usb_device *dev, unsigned int pipe,
  	__u8 request, __u8 requesttype, __u16 value, __u16 index,
  	void *data, __u16 size, int timeout);
  extern int usb_interrupt_msg(struct usb_device *usb_dev, unsigned int pipe,
  	void *data, int len, int *actual_length, int timeout);
  extern int usb_bulk_msg(struct usb_device *usb_dev, unsigned int pipe,
  	void *data, int len, int *actual_length,
  	int timeout);
  
  /* wrappers around usb_control_msg() for the most common standard requests */
  extern int usb_get_descriptor(struct usb_device *dev, unsigned char desctype,
  	unsigned char descindex, void *buf, int size);
  extern int usb_get_status(struct usb_device *dev,
  	int type, int target, void *data);
  extern int usb_string(struct usb_device *dev, int index,
  	char *buf, size_t size);
  
  /* wrappers that also update important state inside usbcore */
  extern int usb_clear_halt(struct usb_device *dev, int pipe);
  extern int usb_reset_configuration(struct usb_device *dev);
  extern int usb_set_interface(struct usb_device *dev, int ifnum, int alternate);
  extern void usb_reset_endpoint(struct usb_device *dev, unsigned int epaddr);
  
  /* this request isn't really synchronous, but it belongs with the others */
  extern int usb_driver_set_configuration(struct usb_device *udev, int config);
  
  /* choose and set configuration for device */
  extern int usb_choose_configuration(struct usb_device *udev);
  extern int usb_set_configuration(struct usb_device *dev, int configuration);
  
  /*
   * timeouts, in milliseconds, used for sending/receiving control messages
   * they typically complete within a few frames (msec) after they're issued
   * USB identifies 5 second timeouts, maybe more in a few cases, and a few
   * slow devices (like some MGE Ellipse UPSes) actually push that limit.
   */
  #define USB_CTRL_GET_TIMEOUT	5000
  #define USB_CTRL_SET_TIMEOUT	5000
  
  
  /**
   * struct usb_sg_request - support for scatter/gather I/O
   * @status: zero indicates success, else negative errno
   * @bytes: counts bytes transferred.
   *
   * These requests are initialized using usb_sg_init(), and then are used
   * as request handles passed to usb_sg_wait() or usb_sg_cancel().  Most
   * members of the request object aren't for driver access.
   *
   * The status and bytecount values are valid only after usb_sg_wait()
   * returns.  If the status is zero, then the bytecount matches the total
   * from the request.
   *
   * After an error completion, drivers may need to clear a halt condition
   * on the endpoint.
   */
  struct usb_sg_request {
  	int			status;
  	size_t			bytes;
  
  	/* private:
  	 * members below are private to usbcore,
  	 * and are not provided for driver access!
  	 */
  	spinlock_t		lock;
  
  	struct usb_device	*dev;
  	int			pipe;
  
  	int			entries;
  	struct urb		**urbs;
  
  	int			count;
  	struct completion	complete;
  };
  
  int usb_sg_init(
  	struct usb_sg_request	*io,
  	struct usb_device	*dev,
  	unsigned		pipe,
  	unsigned		period,
  	struct scatterlist	*sg,
  	int			nents,
  	size_t			length,
  	gfp_t			mem_flags
  );
  void usb_sg_cancel(struct usb_sg_request *io);
  void usb_sg_wait(struct usb_sg_request *io);
  
  
  /* ----------------------------------------------------------------------- */
  
  /*
   * For various legacy reasons, Linux has a small cookie that's paired with
   * a struct usb_device to identify an endpoint queue.  Queue characteristics
   * are defined by the endpoint's descriptor.  This cookie is called a "pipe",
   * an unsigned int encoded as:
   *
   *  - direction:	bit 7		(0 = Host-to-Device [Out],
   *					 1 = Device-to-Host [In] ...
   *					like endpoint bEndpointAddress)
   *  - device address:	bits 8-14       ... bit positions known to uhci-hcd
   *  - endpoint:		bits 15-18      ... bit positions known to uhci-hcd
   *  - pipe type:	bits 30-31	(00 = isochronous, 01 = interrupt,
   *					 10 = control, 11 = bulk)
   *
   * Given the device address and endpoint descriptor, pipes are redundant.
   */
  
  /* NOTE:  these are not the standard USB_ENDPOINT_XFER_* values!! */
  /* (yet ... they're the values used by usbfs) */
  #define PIPE_ISOCHRONOUS		0
  #define PIPE_INTERRUPT			1
  #define PIPE_CONTROL			2
  #define PIPE_BULK			3
  
  #define usb_pipein(pipe)	((pipe) & USB_DIR_IN)
  #define usb_pipeout(pipe)	(!usb_pipein(pipe))
  
  #define usb_pipedevice(pipe)	(((pipe) >> 8) & 0x7f)
  #define usb_pipeendpoint(pipe)	(((pipe) >> 15) & 0xf)
  
  #define usb_pipetype(pipe)	(((pipe) >> 30) & 3)
  #define usb_pipeisoc(pipe)	(usb_pipetype((pipe)) == PIPE_ISOCHRONOUS)
  #define usb_pipeint(pipe)	(usb_pipetype((pipe)) == PIPE_INTERRUPT)
  #define usb_pipecontrol(pipe)	(usb_pipetype((pipe)) == PIPE_CONTROL)
  #define usb_pipebulk(pipe)	(usb_pipetype((pipe)) == PIPE_BULK)
  
  static inline unsigned int __create_pipe(struct usb_device *dev,
  		unsigned int endpoint)
  {
  	return (dev->devnum << 8) | (endpoint << 15);
  }
  
  /* Create various pipes... */
  #define usb_sndctrlpipe(dev, endpoint)	\
  	((PIPE_CONTROL << 30) | __create_pipe(dev, endpoint))
  #define usb_rcvctrlpipe(dev, endpoint)	\
  	((PIPE_CONTROL << 30) | __create_pipe(dev, endpoint) | USB_DIR_IN)
  #define usb_sndisocpipe(dev, endpoint)	\
  	((PIPE_ISOCHRONOUS << 30) | __create_pipe(dev, endpoint))
  #define usb_rcvisocpipe(dev, endpoint)	\
  	((PIPE_ISOCHRONOUS << 30) | __create_pipe(dev, endpoint) | USB_DIR_IN)
  #define usb_sndbulkpipe(dev, endpoint)	\
  	((PIPE_BULK << 30) | __create_pipe(dev, endpoint))
  #define usb_rcvbulkpipe(dev, endpoint)	\
  	((PIPE_BULK << 30) | __create_pipe(dev, endpoint) | USB_DIR_IN)
  #define usb_sndintpipe(dev, endpoint)	\
  	((PIPE_INTERRUPT << 30) | __create_pipe(dev, endpoint))
  #define usb_rcvintpipe(dev, endpoint)	\
  	((PIPE_INTERRUPT << 30) | __create_pipe(dev, endpoint) | USB_DIR_IN)
  
  static inline struct usb_host_endpoint *
  usb_pipe_endpoint(struct usb_device *dev, unsigned int pipe)
  {
  	struct usb_host_endpoint **eps;
  	eps = usb_pipein(pipe) ? dev->ep_in : dev->ep_out;
  	return eps[usb_pipeendpoint(pipe)];
  }
  
  /*-------------------------------------------------------------------------*/
  
  static inline __u16
  usb_maxpacket(struct usb_device *udev, int pipe, int is_out)
  {
  	struct usb_host_endpoint	*ep;
  	unsigned			epnum = usb_pipeendpoint(pipe);
  
  	if (is_out) {
  		WARN_ON(usb_pipein(pipe));
  		ep = udev->ep_out[epnum];
  	} else {
  		WARN_ON(usb_pipeout(pipe));
  		ep = udev->ep_in[epnum];
  	}
  	if (!ep)
  		return 0;
  
  	/* NOTE:  only 0x07ff bits are for packet size... */
  	return usb_endpoint_maxp(&ep->desc);
  }
  
  /* ----------------------------------------------------------------------- */
  
  /* translate USB error codes to codes user space understands */
  static inline int usb_translate_errors(int error_code)
  {
  	switch (error_code) {
  	case 0:
  	case -ENOMEM:
  	case -ENODEV:
  	case -EOPNOTSUPP:
  		return error_code;
  	default:
  		return -EIO;
  	}
  }
  
  /* Events from the usb core */
  #define USB_DEVICE_ADD		0x0001
  #define USB_DEVICE_REMOVE	0x0002
  #define USB_BUS_ADD		0x0003
  #define USB_BUS_REMOVE		0x0004
  extern void usb_register_notify(struct notifier_block *nb);
  extern void usb_unregister_notify(struct notifier_block *nb);
  
  /* debugfs stuff */
  extern struct dentry *usb_debug_root;
  
  /* LED triggers */
  enum usb_led_event {
  	USB_LED_EVENT_HOST = 0,
  	USB_LED_EVENT_GADGET = 1,
  };
  
  #ifdef CONFIG_USB_LED_TRIG
  extern void usb_led_activity(enum usb_led_event ev);
  #else
  static inline void usb_led_activity(enum usb_led_event ev) {}
  #endif
  
  #endif  /* __KERNEL__ */
  
  #endif
  