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      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 */
     89