include/linux/usb/gadgetfs.h

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