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23cd1385 RB |
1 | /* |
2 | * usb/gadget/config.c -- simplify building config descriptors | |
3 | * | |
4 | * Copyright (C) 2003 David Brownell | |
5 | * | |
1a459660 | 6 | * SPDX-License-Identifier: GPL-2.0+ |
23cd1385 RB |
7 | * |
8 | * Ported to U-boot by: Thomas Smits <ts.smits@gmail.com> and | |
9 | * Remy Bohmer <linux@bohmer.net> | |
10 | */ | |
11 | ||
12 | #include <common.h> | |
13 | #include <asm/errno.h> | |
14 | #include <linux/list.h> | |
15 | #include <linux/string.h> | |
16 | ||
17 | #include <linux/usb/ch9.h> | |
18 | #include <linux/usb/gadget.h> | |
19 | ||
20 | ||
21 | /** | |
22 | * usb_descriptor_fillbuf - fill buffer with descriptors | |
23 | * @buf: Buffer to be filled | |
24 | * @buflen: Size of buf | |
25 | * @src: Array of descriptor pointers, terminated by null pointer. | |
26 | * | |
27 | * Copies descriptors into the buffer, returning the length or a | |
28 | * negative error code if they can't all be copied. Useful when | |
29 | * assembling descriptors for an associated set of interfaces used | |
30 | * as part of configuring a composite device; or in other cases where | |
31 | * sets of descriptors need to be marshaled. | |
32 | */ | |
33 | int | |
34 | usb_descriptor_fillbuf(void *buf, unsigned buflen, | |
35 | const struct usb_descriptor_header **src) | |
36 | { | |
37 | u8 *dest = buf; | |
38 | ||
39 | if (!src) | |
40 | return -EINVAL; | |
41 | ||
42 | /* fill buffer from src[] until null descriptor ptr */ | |
43 | for (; NULL != *src; src++) { | |
44 | unsigned len = (*src)->bLength; | |
45 | ||
46 | if (len > buflen) | |
47 | return -EINVAL; | |
48 | memcpy(dest, *src, len); | |
49 | buflen -= len; | |
50 | dest += len; | |
51 | } | |
52 | return dest - (u8 *)buf; | |
53 | } | |
54 | ||
55 | ||
56 | /** | |
57 | * usb_gadget_config_buf - builts a complete configuration descriptor | |
58 | * @config: Header for the descriptor, including characteristics such | |
59 | * as power requirements and number of interfaces. | |
60 | * @desc: Null-terminated vector of pointers to the descriptors (interface, | |
61 | * endpoint, etc) defining all functions in this device configuration. | |
62 | * @buf: Buffer for the resulting configuration descriptor. | |
63 | * @length: Length of buffer. If this is not big enough to hold the | |
64 | * entire configuration descriptor, an error code will be returned. | |
65 | * | |
66 | * This copies descriptors into the response buffer, building a descriptor | |
67 | * for that configuration. It returns the buffer length or a negative | |
68 | * status code. The config.wTotalLength field is set to match the length | |
69 | * of the result, but other descriptor fields (including power usage and | |
70 | * interface count) must be set by the caller. | |
71 | * | |
72 | * Gadget drivers could use this when constructing a config descriptor | |
73 | * in response to USB_REQ_GET_DESCRIPTOR. They will need to patch the | |
74 | * resulting bDescriptorType value if USB_DT_OTHER_SPEED_CONFIG is needed. | |
75 | */ | |
76 | int usb_gadget_config_buf( | |
77 | const struct usb_config_descriptor *config, | |
78 | void *buf, | |
79 | unsigned length, | |
80 | const struct usb_descriptor_header **desc | |
81 | ) | |
82 | { | |
83 | struct usb_config_descriptor *cp = buf; | |
84 | int len; | |
85 | ||
86 | /* config descriptor first */ | |
87 | if (length < USB_DT_CONFIG_SIZE || !desc) | |
88 | return -EINVAL; | |
89 | *cp = *config; | |
90 | ||
91 | /* then interface/endpoint/class/vendor/... */ | |
6142e0ae | 92 | len = usb_descriptor_fillbuf(USB_DT_CONFIG_SIZE + (u8 *)buf, |
23cd1385 RB |
93 | length - USB_DT_CONFIG_SIZE, desc); |
94 | if (len < 0) | |
95 | return len; | |
96 | len += USB_DT_CONFIG_SIZE; | |
97 | if (len > 0xffff) | |
98 | return -EINVAL; | |
99 | ||
100 | /* patch up the config descriptor */ | |
101 | cp->bLength = USB_DT_CONFIG_SIZE; | |
102 | cp->bDescriptorType = USB_DT_CONFIG; | |
103 | cp->wTotalLength = cpu_to_le16(len); | |
104 | cp->bmAttributes |= USB_CONFIG_ATT_ONE; | |
105 | return len; | |
106 | } |