gadgetfs.h (2825B) - Raw
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 and hid 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 */