include/linux/usb/gadgetfs.h

   1 /*
   2  * Filesystem based user-mode API to USB Gadget controller hardware
   3  *
   4  * Other than ep0 operations, most things are done by read() and write()
   5  * on endpoint files found in one directory.  They are configured by
   6  * writing descriptors, and then may be used for normal stream style
   7  * i/o requests.  When ep0 is configured, the device can enumerate;
   8  * when it's closed, the device disconnects from usb.  Operations on
   9  * ep0 require ioctl() operations.
  10  *
  11  * Configuration and device descriptors get written to /dev/gadget/$CHIP,
  12  * which may then be used to read usb_gadgetfs_event structs.  The driver
  13  * may activate endpoints as it handles SET_CONFIGURATION setup events,
  14  * or earlier; writing endpoint descriptors to /dev/gadget/$ENDPOINT
  15  * then performing data transfers by reading or writing.
  16  */
  17
  18 #ifndef __LINUX_USB_GADGETFS_H
  19 #define __LINUX_USB_GADGETFS_H
  20
  21 #include <linux/types.h>
  22 #include <linux/ioctl.h>
  23
  24 #include <linux/usb/ch9.h>
  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
  51                 /* CONNECT: just the speed */
  52                 enum usb_device_speed   speed;
  53
  54                 /* SETUP: packet; DATA phase i/o precedes next event
  55                  *(setup.bmRequestType & USB_DIR_IN) flags direction
  56                  * ... includes SET_CONFIGURATION, SET_INTERFACE
  57                  */
  58                 struct usb_ctrlrequest  setup;
  59         } u;
  60         enum usb_gadgetfs_event_type    type;
  61 };
  62
  63
  64 /* The 'g' code is also used by printer gadget ioctl requests.
  65  * Don't add any colliding codes to either driver, and keep
  66  * them in unique ranges (size 0x20 for now).
  67  */
  68
  69 /* endpoint ioctls */
  70
  71 /* IN transfers may be reported to the gadget driver as complete
  72  *      when the fifo is loaded, before the host reads the data;
  73  * OUT transfers may be reported to the host's "client" driver as
  74  *      complete when they're sitting in the FIFO unread.
  75  * THIS returns how many bytes are "unclaimed" in the endpoint fifo
  76  * (needed for precise fault handling, when the hardware allows it)
  77  */
  78 #define GADGETFS_FIFO_STATUS    _IO('g', 1)
  79
  80 /* discards any unclaimed data in the fifo. */
  81 #define GADGETFS_FIFO_FLUSH     _IO('g', 2)
  82
  83 /* resets endpoint halt+toggle; used to implement set_interface.
  84  * some hardware (like pxa2xx) can't support this.
  85  */
  86 #define GADGETFS_CLEAR_HALT     _IO('g', 3)
  87
  88 #endif /* __LINUX_USB_GADGETFS_H */