cregit-Linux how code gets into the kernel

Release 4.12 include/uapi/linux/usb/gadgetfs.h

 * Filesystem based user-mode API to USB Gadget controller hardware
 * Other than ep0 operations, most things are done by read() and write()
 * on endpoint files found in one directory.  They are configured by
 * writing descriptors, and then may be used for normal stream style
 * i/o requests.  When ep0 is configured, the device can enumerate;
 * when it's closed, the device disconnects from usb.  Operations on
 * ep0 require ioctl() operations.
 * Configuration and device descriptors get written to /dev/gadget/$CHIP,
 * which may then be used to read usb_gadgetfs_event structs.  The driver
 * may activate endpoints as it handles SET_CONFIGURATION setup events,
 * or earlier; writing endpoint descriptors to /dev/gadget/$ENDPOINT
 * then performing data transfers by reading or writing.



#include <linux/types.h>
#include <linux/ioctl.h>

#include <linux/usb/ch9.h>

 * Events are delivered on the ep0 file descriptor, when the user mode driver
 * reads from this file descriptor after writing the descriptors.  Don't
 * stop polling this descriptor.

enum usb_gadgetfs_event_type {

	/* and likely more ! */

/* NOTE:  this structure must stay the same size and layout on
 * both 32-bit and 64-bit kernels.

struct usb_gadgetfs_event {
	union {
                 * ... some hardware can't report disconnection

		/* CONNECT: just the speed */
enum usb_device_speed	speed;

		/* SETUP: packet; DATA phase i/o precedes next event
                 *(setup.bmRequestType & USB_DIR_IN) flags direction
                 * ... includes SET_CONFIGURATION, SET_INTERFACE
struct usb_ctrlrequest	setup;
} u;
enum usb_gadgetfs_event_type	type;

/* The 'g' code is also used by printer gadget ioctl requests.
 * Don't add any colliding codes to either driver, and keep
 * them in unique ranges (size 0x20 for now).

/* endpoint ioctls */

/* IN transfers may be reported to the gadget driver as complete
 *      when the fifo is loaded, before the host reads the data;
 * OUT transfers may be reported to the host's "client" driver as
 *      complete when they're sitting in the FIFO unread.
 * THIS returns how many bytes are "unclaimed" in the endpoint fifo
 * (needed for precise fault handling, when the hardware allows it)

#define	GADGETFS_FIFO_STATUS	_IO('g', 1)

/* discards any unclaimed data in the fifo. */

#define	GADGETFS_FIFO_FLUSH	_IO('g', 2)

/* resets endpoint halt+toggle; used to implement set_interface.
 * some hardware (like pxa2xx) can't support this.

#define	GADGETFS_CLEAR_HALT	_IO('g', 3)

#endif /* __LINUX_USB_GADGETFS_H */

Overall Contributors

David Brownell7086.42%337.50%
Greg Kroah-Hartman89.88%225.00%
Jaswinder Singh Rajput11.23%112.50%
Craig W. Nadler11.23%112.50%
Robert P. J. Day11.23%112.50%
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.