text: #ifndef __LINUX_FUNCTIONFS_H__
  #define __LINUX_FUNCTIONFS_H__
  
  
  #include <linux/types.h>
  #include <linux/ioctl.h>
  
  #include <linux/usb/ch9.h>
  
  
  enum {
  	FUNCTIONFS_DESCRIPTORS_MAGIC = 1,
  	FUNCTIONFS_STRINGS_MAGIC = 2,
  	FUNCTIONFS_DESCRIPTORS_MAGIC_V2 = 3,
  };
  
  enum functionfs_flags {
  	FUNCTIONFS_HAS_FS_DESC = 1,
  	FUNCTIONFS_HAS_HS_DESC = 2,
  	FUNCTIONFS_HAS_SS_DESC = 4,
  	FUNCTIONFS_HAS_MS_OS_DESC = 8,
  	FUNCTIONFS_VIRTUAL_ADDR = 16,
  	FUNCTIONFS_EVENTFD = 32,
  };
  
  /* Descriptor of an non-audio endpoint */
  struct usb_endpoint_descriptor_no_audio {
  	__u8  bLength;
  	__u8  bDescriptorType;
  
  	__u8  bEndpointAddress;
  	__u8  bmAttributes;
  	__le16 wMaxPacketSize;
  	__u8  bInterval;
  } __attribute__((packed));
  
  struct usb_functionfs_descs_head_v2 {
  	__le32 magic;
  	__le32 length;
  	__le32 flags;
  	/*
  	 * __le32 fs_count, hs_count, fs_count; must be included manually in
  	 * the structure taking flags into consideration.
  	 */
  } __attribute__((packed));
  
  /* Legacy format, deprecated as of 3.14. */
  struct usb_functionfs_descs_head {
  	__le32 magic;
  	__le32 length;
  	__le32 fs_count;
  	__le32 hs_count;
  } __attribute__((packed, deprecated));
  
  /* MS OS Descriptor header */
  struct usb_os_desc_header {
  	__u8	interface;
  	__le32	dwLength;
  	__le16	bcdVersion;
  	__le16	wIndex;
  	union {
  		struct {
  			__u8	bCount;
  			__u8	Reserved;
  		};
  		__le16	wCount;
  	};
  } __attribute__((packed));
  
  struct usb_ext_compat_desc {
  	__u8	bFirstInterfaceNumber;
  	__u8	Reserved1;
  	__u8	CompatibleID[8];
  	__u8	SubCompatibleID[8];
  	__u8	Reserved2[6];
  };
  
  struct usb_ext_prop_desc {
  	__le32	dwSize;
  	__le32	dwPropertyDataType;
  	__le16	wPropertyNameLength;
  } __attribute__((packed));
  
  
  /*
   * Descriptors format:
   *
   * | off | name      | type         | description                          |
   * |-----+-----------+--------------+--------------------------------------|
   * |   0 | magic     | LE32         | FUNCTIONFS_DESCRIPTORS_MAGIC_V2      |
   * |   4 | length    | LE32         | length of the whole data chunk       |
   * |   8 | flags     | LE32         | combination of functionfs_flags      |
   * |     | fs_count  | LE32         | number of full-speed descriptors     |
   * |     | hs_count  | LE32         | number of high-speed descriptors     |
   * |     | ss_count  | LE32         | number of super-speed descriptors    |
   * |     | os_count  | LE32         | number of MS OS descriptors          |
   * |     | fs_descrs | Descriptor[] | list of full-speed descriptors       |
   * |     | hs_descrs | Descriptor[] | list of high-speed descriptors       |
   * |     | ss_descrs | Descriptor[] | list of super-speed descriptors      |
   * |     | os_descrs | OSDesc[]     | list of MS OS descriptors            |
   *
   * Depending on which flags are set, various fields may be missing in the
   * structure.  Any flags that are not recognised cause the whole block to be
   * rejected with -ENOSYS.
   *
   * Legacy descriptors format (deprecated as of 3.14):
   *
   * | off | name      | type         | description                          |
   * |-----+-----------+--------------+--------------------------------------|
   * |   0 | magic     | LE32         | FUNCTIONFS_DESCRIPTORS_MAGIC         |
   * |   4 | length    | LE32         | length of the whole data chunk       |
   * |   8 | fs_count  | LE32         | number of full-speed descriptors     |
   * |  12 | hs_count  | LE32         | number of high-speed descriptors     |
   * |  16 | fs_descrs | Descriptor[] | list of full-speed descriptors       |
   * |     | hs_descrs | Descriptor[] | list of high-speed descriptors       |
   *
   * All numbers must be in little endian order.
   *
   * Descriptor[] is an array of valid USB descriptors which have the following
   * format:
   *
   * | off | name            | type | description              |
   * |-----+-----------------+------+--------------------------|
   * |   0 | bLength         | U8   | length of the descriptor |
   * |   1 | bDescriptorType | U8   | descriptor type          |
   * |   2 | payload         |      | descriptor's payload     |
   *
   * OSDesc[] is an array of valid MS OS Feature Descriptors which have one of
   * the following formats:
   *
   * | off | name            | type | description              |
   * |-----+-----------------+------+--------------------------|
   * |   0 | inteface        | U8   | related interface number |
   * |   1 | dwLength        | U32  | length of the descriptor |
   * |   5 | bcdVersion      | U16  | currently supported: 1   |
   * |   7 | wIndex          | U16  | currently supported: 4   |
   * |   9 | bCount          | U8   | number of ext. compat.   |
   * |  10 | Reserved        | U8   | 0                        |
   * |  11 | ExtCompat[]     |      | list of ext. compat. d.  |
   *
   * | off | name            | type | description              |
   * |-----+-----------------+------+--------------------------|
   * |   0 | inteface        | U8   | related interface number |
   * |   1 | dwLength        | U32  | length of the descriptor |
   * |   5 | bcdVersion      | U16  | currently supported: 1   |
   * |   7 | wIndex          | U16  | currently supported: 5   |
   * |   9 | wCount          | U16  | number of ext. compat.   |
   * |  11 | ExtProp[]       |      | list of ext. prop. d.    |
   *
   * ExtCompat[] is an array of valid Extended Compatiblity descriptors
   * which have the following format:
   *
   * | off | name                  | type | description                         |
   * |-----+-----------------------+------+-------------------------------------|
   * |   0 | bFirstInterfaceNumber | U8   | index of the interface or of the 1st|
   * |     |                       |      | interface in an IAD group           |
   * |   1 | Reserved              | U8   | 0                                   |
   * |   2 | CompatibleID          | U8[8]| compatible ID string                |
   * |  10 | SubCompatibleID       | U8[8]| subcompatible ID string             |
   * |  18 | Reserved              | U8[6]| 0                                   |
   *
   * ExtProp[] is an array of valid Extended Properties descriptors
   * which have the following format:
   *
   * | off | name                  | type | description                         |
   * |-----+-----------------------+------+-------------------------------------|
   * |   0 | dwSize                | U32  | length of the descriptor            |
   * |   4 | dwPropertyDataType    | U32  | 1..7                                |
   * |   8 | wPropertyNameLength   | U16  | bPropertyName length (NL)           |
   * |  10 | bPropertyName         |U8[NL]| name of this property               |
   * |10+NL| dwPropertyDataLength  | U32  | bPropertyData length (DL)           |
   * |14+NL| bProperty             |U8[DL]| payload of this property            |
   */
  
  struct usb_functionfs_strings_head {
  	__le32 magic;
  	__le32 length;
  	__le32 str_count;
  	__le32 lang_count;
  } __attribute__((packed));
  
  /*
   * Strings format:
   *
   * | off | name       | type                  | description                |
   * |-----+------------+-----------------------+----------------------------|
   * |   0 | magic      | LE32                  | FUNCTIONFS_STRINGS_MAGIC   |
   * |   4 | length     | LE32                  | length of the data chunk   |
   * |   8 | str_count  | LE32                  | number of strings          |
   * |  12 | lang_count | LE32                  | number of languages        |
   * |  16 | stringtab  | StringTab[lang_count] | table of strings per lang  |
   *
   * For each language there is one stringtab entry (ie. there are lang_count
   * stringtab entires).  Each StringTab has following format:
   *
   * | off | name    | type              | description                        |
   * |-----+---------+-------------------+------------------------------------|
   * |   0 | lang    | LE16              | language code                      |
   * |   2 | strings | String[str_count] | array of strings in given language |
   *
   * For each string there is one strings entry (ie. there are str_count
   * string entries).  Each String is a NUL terminated string encoded in
   * UTF-8.
   */
  
  
  
  /*
   * Events are delivered on the ep0 file descriptor, when the user mode driver
   * reads from this file descriptor after writing the descriptors.  Don't
   * stop polling this descriptor.
   */
  
  enum usb_functionfs_event_type {
  	FUNCTIONFS_BIND,
  	FUNCTIONFS_UNBIND,
  
  	FUNCTIONFS_ENABLE,
  	FUNCTIONFS_DISABLE,
  
  	FUNCTIONFS_SETUP,
  
  	FUNCTIONFS_SUSPEND,
  	FUNCTIONFS_RESUME
  };
  
  /* NOTE:  this structure must stay the same size and layout on
   * both 32-bit and 64-bit kernels.
   */
  struct usb_functionfs_event {
  	union {
  		/* SETUP: packet; DATA phase i/o precedes next event
  		 *(setup.bmRequestType & USB_DIR_IN) flags direction */
  		struct usb_ctrlrequest	setup;
  	} __attribute__((packed)) u;
  
  	/* enum usb_functionfs_event_type */
  	__u8				type;
  	__u8				_pad[3];
  } __attribute__((packed));
  
  
  /* Endpoint ioctls */
  /* The same as in gadgetfs */
  
  /* IN transfers may be reported to the gadget driver as complete
   *	when the fifo is loaded, before the host reads the data;
   * OUT transfers may be reported to the host's "client" driver as
   *	complete when they're sitting in the FIFO unread.
   * THIS returns how many bytes are "unclaimed" in the endpoint fifo
   * (needed for precise fault handling, when the hardware allows it)
   */
  #define	FUNCTIONFS_FIFO_STATUS	_IO('g', 1)
  
  /* discards any unclaimed data in the fifo. */
  #define	FUNCTIONFS_FIFO_FLUSH	_IO('g', 2)
  
  /* resets endpoint halt+toggle; used to implement set_interface.
   * some hardware (like pxa2xx) can't support this.
   */
  #define	FUNCTIONFS_CLEAR_HALT	_IO('g', 3)
  
  /* Specific for functionfs */
  
  /*
   * Returns reverse mapping of an interface.  Called on EP0.  If there
   * is no such interface returns -EDOM.  If function is not active
   * returns -ENODEV.
   */
  #define	FUNCTIONFS_INTERFACE_REVMAP	_IO('g', 128)
  
  /*
   * Returns real bEndpointAddress of an endpoint.  If function is not
   * active returns -ENODEV.
   */
  #define	FUNCTIONFS_ENDPOINT_REVMAP	_IO('g', 129)
  
  /*
   * Returns endpoint descriptor. If function is not active returns -ENODEV.
   */
  #define	FUNCTIONFS_ENDPOINT_DESC	_IOR('g', 130, \
  					     struct usb_endpoint_descriptor)
  
  
  
  #endif /* __LINUX_FUNCTIONFS_H__ */
  