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
  33 enum 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  */
  46 struct 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 */