1 /* SPDX-License-Identifier: GPL-2.0 */
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
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.
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.
17 * There's also "Wireless USB", using low power short range radios for
18 * peripheral interconnection but otherwise building on the USB framework.
20 * Note all descriptors are declared '__attribute__((packed))' so that:
22 * [a] they never get padded, either internally (USB spec writers
23 * probably handled that) or externally;
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
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.
33 #ifndef __LINUX_USB_CH9_H
34 #define __LINUX_USB_CH9_H
36 #include <linux/device.h>
37 #include <uapi/linux/usb/ch9.h>
39 /* USB 3.2 SuperSpeed Plus phy signaling rate generation and lane count */
42 USB_SSP_GEN_UNKNOWN = 0,
48 extern const char *usb_ep_type_string(int ep_type);
49 extern const char *usb_speed_string(enum usb_device_speed speed);
50 extern enum usb_device_speed usb_get_maximum_speed(struct device *dev);
51 extern enum usb_ssp_rate usb_get_maximum_ssp_rate(struct device *dev);
52 extern const char *usb_state_string(enum usb_device_state state);
53 unsigned int usb_decode_interval(const struct usb_endpoint_descriptor *epd,
54 enum usb_device_speed speed);
57 extern const char *usb_decode_ctrl(char *str, size_t size, __u8 bRequestType,
58 __u8 bRequest, __u16 wValue, __u16 wIndex,
62 #endif /* __LINUX_USB_CH9_H */