LXR linux/include/uapi/linux/usb/gadgetfs.h

   1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2/*
   3 * Filesystem based user-mode API to USB Gadget controller hardware
   4 *
   5 * Other than ep0 operations, most things are done by read() and write()
   6 * on endpoint files found in one directory.  They are configured by
   7 * writing descriptors, and then may be used for normal stream style
   8 * i/o requests.  When ep0 is configured, the device can enumerate;
   9 * when it's closed, the device disconnects from usb.  Operations on
  10 * ep0 require ioctl() operations.
  11 *
  12 * Configuration and device descriptors get written to /dev/gadget/$CHIP,
  13 * which may then be used to read usb_gadgetfs_event structs.  The driver
  14 * may activate endpoints as it handles SET_CONFIGURATION setup events,
  15 * or earlier; writing endpoint descriptors to /dev/gadget/$ENDPOINT
  16 * then performing data transfers by reading or writing.
  17 */
  18
  19#ifndef __LINUX_USB_GADGETFS_H
  20#define __LINUX_USB_GADGETFS_H
  21
  22#include <linux/types.h>
  23#include <linux/ioctl.h>
  24
  25#include <linux/usb/ch9.h>
  26
  27/*
  28 * Events are delivered on the ep0 file descriptor, when the user mode driver
  29 * reads from this file descriptor after writing the descriptors.  Don't
  30 * stop polling this descriptor.
  31 */
  32
  33enum usb_gadgetfs_event_type {
  34        GADGETFS_NOP = 0,
  35
  36        GADGETFS_CONNECT,
  37        GADGETFS_DISCONNECT,
  38        GADGETFS_SETUP,
  39        GADGETFS_SUSPEND,
  40        /* and likely more ! */
  41};
  42
  43/* NOTE:  this structure must stay the same size and layout on
  44 * both 32-bit and 64-bit kernels.
  45 */
  46struct usb_gadgetfs_event {
  47        union {
  48                /* NOP, DISCONNECT, SUSPEND: nothing
  49                 * ... some hardware can't report disconnection
  50                 */
  51
  52                /* CONNECT: just the speed */
  53                enum usb_device_speed   speed;
  54
  55                /* SETUP: packet; DATA phase i/o precedes next event
  56                 *(setup.bmRequestType & USB_DIR_IN) flags direction
  57                 * ... includes SET_CONFIGURATION, SET_INTERFACE
  58                 */
  59                struct usb_ctrlrequest  setup;
  60        } u;
  61        enum usb_gadgetfs_event_type    type;
  62};
  63
  64
  65/* The 'g' code is also used by printer gadget ioctl requests.
  66 * Don't add any colliding codes to either driver, and keep
  67 * them in unique ranges (size 0x20 for now).
  68 */
  69
  70/* endpoint ioctls */
  71
  72/* IN transfers may be reported to the gadget driver as complete
  73 *      when the fifo is loaded, before the host reads the data;
  74 * OUT transfers may be reported to the host's "client" driver as
  75 *      complete when they're sitting in the FIFO unread.
  76 * THIS returns how many bytes are "unclaimed" in the endpoint fifo
  77 * (needed for precise fault handling, when the hardware allows it)
  78 */
  79#define GADGETFS_FIFO_STATUS    _IO('g', 1)
  80
  81/* discards any unclaimed data in the fifo. */
  82#define GADGETFS_FIFO_FLUSH     _IO('g', 2)
  83
  84/* resets endpoint halt+toggle; used to implement set_interface.
  85 * some hardware (like pxa2xx) can't support this.
  86 */
  87#define GADGETFS_CLEAR_HALT     _IO('g', 3)
  88
  89#endif /* __LINUX_USB_GADGETFS_H */
  90