TOMOYO Linux Cross Reference
Linux/include/linux/usb.h

   #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
   * @ssp_isoc_ep_comp: SuperSpeedPlus isoc 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 usb_ssp_isoc_ep_comp_descriptor  ssp_isoc_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,
 };
 
 int __must_check
 usb_find_common_endpoints(struct usb_host_interface *alt,
                 struct usb_endpoint_descriptor **bulk_in,
                 struct usb_endpoint_descriptor **bulk_out,
                 struct usb_endpoint_descriptor **int_in,
                 struct usb_endpoint_descriptor **int_out);
 
 int __must_check
 usb_find_common_endpoints_reverse(struct usb_host_interface *alt,
                 struct usb_endpoint_descriptor **bulk_in,
                 struct usb_endpoint_descriptor **bulk_out,
                 struct usb_endpoint_descriptor **int_in,
                 struct usb_endpoint_descriptor **int_out);
 
 static inline int __must_check
 usb_find_bulk_in_endpoint(struct usb_host_interface *alt,
                 struct usb_endpoint_descriptor **bulk_in)
 {
         return usb_find_common_endpoints(alt, bulk_in, NULL, NULL, NULL);
 }
 
 static inline int __must_check
 usb_find_bulk_out_endpoint(struct usb_host_interface *alt,
                 struct usb_endpoint_descriptor **bulk_out)
 {
         return usb_find_common_endpoints(alt, NULL, bulk_out, NULL, NULL);
 }
 
 static inline int __must_check
 usb_find_int_in_endpoint(struct usb_host_interface *alt,
                 struct usb_endpoint_descriptor **int_in)
 {
         return usb_find_common_endpoints(alt, NULL, NULL, int_in, NULL);
 }
 
 static inline int __must_check
 usb_find_int_out_endpoint(struct usb_host_interface *alt,
                 struct usb_endpoint_descriptor **int_out)
 {
         return usb_find_common_endpoints(alt, NULL, NULL, NULL, int_out);
 }
 
 static inline int __must_check
 usb_find_last_bulk_in_endpoint(struct usb_host_interface *alt,
                 struct usb_endpoint_descriptor **bulk_in)
 {
         return usb_find_common_endpoints_reverse(alt, bulk_in, NULL, NULL, NULL);
 }
 
 static inline int __must_check
 usb_find_last_bulk_out_endpoint(struct usb_host_interface *alt,
                 struct usb_endpoint_descriptor **bulk_out)
 {
         return usb_find_common_endpoints_reverse(alt, NULL, bulk_out, NULL, NULL);
 }
 
 static inline int __must_check
 usb_find_last_int_in_endpoint(struct usb_host_interface *alt,
                 struct usb_endpoint_descriptor **int_in)
 {
         return usb_find_common_endpoints_reverse(alt, NULL, NULL, int_in, NULL);
 }
 
 static inline int __must_check
 usb_find_last_int_out_endpoint(struct usb_host_interface *alt,
                 struct usb_endpoint_descriptor **int_out)
 {
         return usb_find_common_endpoints_reverse(alt, NULL, NULL, NULL, int_out);
 }
 
 /**
  * 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.
  * @authorized: This allows to (de)authorize individual interfaces instead
  *      a whole device in contrast to the device authorization.
  * @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 */
         unsigned authorized:1;          /* used for interface authorization */
 
         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 /sys/kernel/debug/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_ssp_cap_descriptor   *ssp_cap;
         struct usb_ss_container_id_descriptor   *ss_id;
         struct usb_ptm_cap_descriptor   *ptm_cap;
 };
 
 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 */
         struct device *sysdev;          /* as seen from firmware or bus */
         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 mutex devnum_next_mutex; /* devnum_next mutex */
 
         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 */
 
         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_u1_enabled: USB3 hardware U1 LPM enabled
  * @usb3_lpm_u2_enabled: USB3 hardware U2 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_u1_enabled:1;
         unsigned usb3_lpm_u2_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_lock_device_interruptible(udev)     device_lock_interruptible(&(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 1, 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_deregister_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
 

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