1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * This file holds USB constants and structures that are needed for
4  * USB device APIs.  These are used by the USB device model, which is
5  * defined in chapter 9 of the USB 2.0 specification and in the
6  * Wireless USB 1.0 (spread around).  Linux has several APIs in C that
7  * need these:
8  *
9  * - the host side Linux-USB kernel driver API;
10  * - the "usbfs" user space API; and
11  * - the Linux "gadget" device/peripheral side driver API.
12  *
13  * USB 2.0 adds an additional "On The Go" (OTG) mode, which lets systems
14  * act either as a USB host or as a USB device.  That means the host and
15  * device side APIs benefit from working well together.
16  *
17  * There's also "Wireless USB", using low power short range radios for
18  * peripheral interconnection but otherwise building on the USB framework.
19  *
20  * Note all descriptors are declared '__attribute__((packed))' so that:
21  *
22  * [a] they never get padded, either internally (USB spec writers
23  *     probably handled that) or externally;
24  *
25  * [b] so that accessing bigger-than-a-bytes fields will never
26  *     generate bus errors on any platform, even when the location of
27  *     its descriptor inside a bundle isn't "naturally aligned", and
28  *
29  * [c] for consistency, removing all doubt even when it appears to
30  *     someone that the two other points are non-issues for that
31  *     particular descriptor type.
32  */
33 #ifndef __LINUX_USB_CH9_H
34 #define __LINUX_USB_CH9_H
35 
36 #include <uapi/linux/usb/ch9.h>
37 
38 /* USB 3.2 SuperSpeed Plus phy signaling rate generation and lane count */
39 
40 enum usb_ssp_rate {
41 	USB_SSP_GEN_UNKNOWN = 0,
42 	USB_SSP_GEN_2x1,
43 	USB_SSP_GEN_1x2,
44 	USB_SSP_GEN_2x2,
45 };
46 
47 struct device;
48 
49 extern const char *usb_ep_type_string(int ep_type);
50 extern const char *usb_speed_string(enum usb_device_speed speed);
51 extern enum usb_device_speed usb_get_maximum_speed(struct device *dev);
52 extern enum usb_ssp_rate usb_get_maximum_ssp_rate(struct device *dev);
53 extern const char *usb_state_string(enum usb_device_state state);
54 unsigned int usb_decode_interval(const struct usb_endpoint_descriptor *epd,
55 				 enum usb_device_speed speed);
56 
57 #ifdef CONFIG_TRACING
58 extern const char *usb_decode_ctrl(char *str, size_t size, __u8 bRequestType,
59 				   __u8 bRequest, __u16 wValue, __u16 wIndex,
60 				   __u16 wLength);
61 #endif
62 
63 #endif /* __LINUX_USB_CH9_H */
64