xref: /bsp/allwinner/libraries/sunxi-hal/hal/source/usb/include/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;

/* 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.
 * @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.
 * @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;
//  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_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, size_t min);
#define usb_get_extra_descriptor(ifpoint, type, ptr) \
                __usb_get_extra_descriptor((ifpoint)->extra, \
                (ifpoint)->extralen, \
                type, (void **)ptr, sizeof(**(ptr)))

/* ----------------------------------------------------------------------- */

/* USB device number allocation bitmap */
struct usb_devmap {
    unsigned long devicemap[128 / (8*sizeof(unsigned long))];
};


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_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.
 */

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)];
}

/* ----------------------------------------------------------------------- */

/* 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