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 <linux/device.h> 37 #include <uapi/linux/usb/ch9.h> 38 39 /** 40 * usb_ep_type_string() - Returns human readable-name of the endpoint type. 41 * @ep_type: The endpoint type to return human-readable name for. If it's not 42 * any of the types: USB_ENDPOINT_XFER_{CONTROL, ISOC, BULK, INT}, 43 * usually got by usb_endpoint_type(), the string 'unknown' will be returned. 44 */ 45 extern const char *usb_ep_type_string(int ep_type); 46 47 /** 48 * usb_speed_string() - Returns human readable-name of the speed. 49 * @speed: The speed to return human-readable name for. If it's not 50 * any of the speeds defined in usb_device_speed enum, string for 51 * USB_SPEED_UNKNOWN will be returned. 52 */ 53 extern const char *usb_speed_string(enum usb_device_speed speed); 54 55 /** 56 * usb_get_maximum_speed - Get maximum requested speed for a given USB 57 * controller. 58 * @dev: Pointer to the given USB controller device 59 * 60 * The function gets the maximum speed string from property "maximum-speed", 61 * and returns the corresponding enum usb_device_speed. 62 */ 63 extern enum usb_device_speed usb_get_maximum_speed(struct device *dev); 64 65 /** 66 * usb_state_string - Returns human readable name for the state. 67 * @state: The state to return a human-readable name for. If it's not 68 * any of the states devices in usb_device_state_string enum, 69 * the string UNKNOWN will be returned. 70 */ 71 extern const char *usb_state_string(enum usb_device_state state); 72 73 #ifdef CONFIG_TRACING 74 /** 75 * usb_decode_ctrl - Returns human readable representation of control request. 76 * @str: buffer to return a human-readable representation of control request. 77 * This buffer should have about 200 bytes. 78 * @size: size of str buffer. 79 * @bRequestType: matches the USB bmRequestType field 80 * @bRequest: matches the USB bRequest field 81 * @wValue: matches the USB wValue field (CPU byte order) 82 * @wIndex: matches the USB wIndex field (CPU byte order) 83 * @wLength: matches the USB wLength field (CPU byte order) 84 * 85 * Function returns decoded, formatted and human-readable description of 86 * control request packet. 87 * 88 * The usage scenario for this is for tracepoints, so function as a return 89 * use the same value as in parameters. This approach allows to use this 90 * function in TP_printk 91 * 92 * Important: wValue, wIndex, wLength parameters before invoking this function 93 * should be processed by le16_to_cpu macro. 94 */ 95 extern const char *usb_decode_ctrl(char *str, size_t size, __u8 bRequestType, 96 __u8 bRequest, __u16 wValue, __u16 wIndex, 97 __u16 wLength); 98 #endif 99 100 #endif /* __LINUX_USB_CH9_H */ 101
