1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux 1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 /* 2 /*
3 * Filesystem based user-mode API to USB Gadge 3 * Filesystem based user-mode API to USB Gadget controller hardware
4 * 4 *
5 * Other than ep0 operations, most things are 5 * Other than ep0 operations, most things are done by read() and write()
6 * on endpoint files found in one directory. 6 * on endpoint files found in one directory. They are configured by
7 * writing descriptors, and then may be used f 7 * writing descriptors, and then may be used for normal stream style
8 * i/o requests. When ep0 is configured, the 8 * i/o requests. When ep0 is configured, the device can enumerate;
9 * when it's closed, the device disconnects fr 9 * when it's closed, the device disconnects from usb. Operations on
10 * ep0 require ioctl() operations. 10 * ep0 require ioctl() operations.
11 * 11 *
12 * Configuration and device descriptors get wr 12 * Configuration and device descriptors get written to /dev/gadget/$CHIP,
13 * which may then be used to read usb_gadgetfs 13 * which may then be used to read usb_gadgetfs_event structs. The driver
14 * may activate endpoints as it handles SET_CO 14 * may activate endpoints as it handles SET_CONFIGURATION setup events,
15 * or earlier; writing endpoint descriptors to 15 * or earlier; writing endpoint descriptors to /dev/gadget/$ENDPOINT
16 * then performing data transfers by reading o 16 * then performing data transfers by reading or writing.
17 */ 17 */
18 18
19 #ifndef __LINUX_USB_GADGETFS_H 19 #ifndef __LINUX_USB_GADGETFS_H
20 #define __LINUX_USB_GADGETFS_H 20 #define __LINUX_USB_GADGETFS_H
21 21
22 #include <linux/types.h> 22 #include <linux/types.h>
23 #include <linux/ioctl.h> 23 #include <linux/ioctl.h>
24 24
25 #include <linux/usb/ch9.h> 25 #include <linux/usb/ch9.h>
26 26
27 /* 27 /*
28 * Events are delivered on the ep0 file descri 28 * Events are delivered on the ep0 file descriptor, when the user mode driver
29 * reads from this file descriptor after writi 29 * reads from this file descriptor after writing the descriptors. Don't
30 * stop polling this descriptor. 30 * stop polling this descriptor.
31 */ 31 */
32 32
33 enum usb_gadgetfs_event_type { 33 enum usb_gadgetfs_event_type {
34 GADGETFS_NOP = 0, 34 GADGETFS_NOP = 0,
35 35
36 GADGETFS_CONNECT, 36 GADGETFS_CONNECT,
37 GADGETFS_DISCONNECT, 37 GADGETFS_DISCONNECT,
38 GADGETFS_SETUP, 38 GADGETFS_SETUP,
39 GADGETFS_SUSPEND, 39 GADGETFS_SUSPEND,
40 /* and likely more ! */ 40 /* and likely more ! */
41 }; 41 };
42 42
43 /* NOTE: this structure must stay the same si 43 /* NOTE: this structure must stay the same size and layout on
44 * both 32-bit and 64-bit kernels. 44 * both 32-bit and 64-bit kernels.
45 */ 45 */
46 struct usb_gadgetfs_event { 46 struct usb_gadgetfs_event {
47 union { 47 union {
48 /* NOP, DISCONNECT, SUSPEND: n 48 /* NOP, DISCONNECT, SUSPEND: nothing
49 * ... some hardware can't rep 49 * ... some hardware can't report disconnection
50 */ 50 */
51 51
52 /* CONNECT: just the speed */ 52 /* CONNECT: just the speed */
53 enum usb_device_speed speed; 53 enum usb_device_speed speed;
54 54
55 /* SETUP: packet; DATA phase i 55 /* SETUP: packet; DATA phase i/o precedes next event
56 *(setup.bmRequestType & USB_D 56 *(setup.bmRequestType & USB_DIR_IN) flags direction
57 * ... includes SET_CONFIGURAT 57 * ... includes SET_CONFIGURATION, SET_INTERFACE
58 */ 58 */
59 struct usb_ctrlrequest setup; 59 struct usb_ctrlrequest setup;
60 } u; 60 } u;
61 enum usb_gadgetfs_event_type type; 61 enum usb_gadgetfs_event_type type;
62 }; 62 };
63 63
64 64
65 /* The 'g' code is also used by printer and hi 65 /* The 'g' code is also used by printer and hid gadget ioctl requests.
66 * Don't add any colliding codes to either dri 66 * Don't add any colliding codes to either driver, and keep
67 * them in unique ranges (size 0x20 for now). 67 * them in unique ranges (size 0x20 for now).
68 */ 68 */
69 69
70 /* endpoint ioctls */ 70 /* endpoint ioctls */
71 71
72 /* IN transfers may be reported to the gadget 72 /* IN transfers may be reported to the gadget driver as complete
73 * when the fifo is loaded, before the ho 73 * when the fifo is loaded, before the host reads the data;
74 * OUT transfers may be reported to the host's 74 * OUT transfers may be reported to the host's "client" driver as
75 * complete when they're sitting in the F 75 * complete when they're sitting in the FIFO unread.
76 * THIS returns how many bytes are "unclaimed" 76 * THIS returns how many bytes are "unclaimed" in the endpoint fifo
77 * (needed for precise fault handling, when th 77 * (needed for precise fault handling, when the hardware allows it)
78 */ 78 */
79 #define GADGETFS_FIFO_STATUS _IO('g', 1) 79 #define GADGETFS_FIFO_STATUS _IO('g', 1)
80 80
81 /* discards any unclaimed data in the fifo. */ 81 /* discards any unclaimed data in the fifo. */
82 #define GADGETFS_FIFO_FLUSH _IO('g', 2) 82 #define GADGETFS_FIFO_FLUSH _IO('g', 2)
83 83
84 /* resets endpoint halt+toggle; used to implem 84 /* resets endpoint halt+toggle; used to implement set_interface.
85 * some hardware (like pxa2xx) can't support t 85 * some hardware (like pxa2xx) can't support this.
86 */ 86 */
87 #define GADGETFS_CLEAR_HALT _IO('g', 3) 87 #define GADGETFS_CLEAR_HALT _IO('g', 3)
88 88
89 #endif /* __LINUX_USB_GADGETFS_H */ 89 #endif /* __LINUX_USB_GADGETFS_H */
90 90
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