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 spec (now defunct). 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 * Note all descriptors are declared '__attribute__((packed))' so that: 18 * 19 * [a] they never get padded, either internally (USB spec writers 20 * probably handled that) or externally; 21 * 22 * [b] so that accessing bigger-than-a-bytes fields will never 23 * generate bus errors on any platform, even when the location of 24 * its descriptor inside a bundle isn't "naturally aligned", and 25 * 26 * [c] for consistency, removing all doubt even when it appears to 27 * someone that the two other points are non-issues for that 28 * particular descriptor type. 29 */ 30 #ifndef __LINUX_USB_CH9_H 31 #define __LINUX_USB_CH9_H 32 33 #include <uapi/linux/usb/ch9.h> 34 35 /* USB 3.2 SuperSpeed Plus phy signaling rate generation and lane count */ 36 37 enum usb_ssp_rate { 38 USB_SSP_GEN_UNKNOWN = 0, 39 USB_SSP_GEN_2x1, 40 USB_SSP_GEN_1x2, 41 USB_SSP_GEN_2x2, 42 }; 43 44 struct device; 45 46 extern const char *usb_ep_type_string(int ep_type); 47 extern const char *usb_speed_string(enum usb_device_speed speed); 48 extern enum usb_device_speed usb_get_maximum_speed(struct device *dev); 49 extern enum usb_ssp_rate usb_get_maximum_ssp_rate(struct device *dev); 50 extern const char *usb_state_string(enum usb_device_state state); 51 unsigned int usb_decode_interval(const struct usb_endpoint_descriptor *epd, 52 enum usb_device_speed speed); 53 54 #ifdef CONFIG_TRACING 55 extern const char *usb_decode_ctrl(char *str, size_t size, __u8 bRequestType, 56 __u8 bRequest, __u16 wValue, __u16 wIndex, 57 __u16 wLength); 58 #endif 59 60 #endif /* __LINUX_USB_CH9_H */ 61
