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 master/host side Linux-USB kernel driver API;
10 * - the "usbfs" user space API; and
11 * - the Linux "gadget" slave/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 master/host or as a USB slave/device. That means
15 * the master and slave 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 */