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1da177e4 LT |
1 | /* |
2 | * usb/gadget/config.c -- simplify building config descriptors | |
3 | * | |
4 | * Copyright (C) 2003 David Brownell | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
19 | */ | |
20 | ||
21 | #include <linux/errno.h> | |
22 | #include <linux/kernel.h> | |
23 | #include <linux/list.h> | |
24 | #include <linux/string.h> | |
25 | #include <linux/device.h> | |
26 | ||
5f848137 | 27 | #include <linux/usb/ch9.h> |
1da177e4 LT |
28 | #include <linux/usb_gadget.h> |
29 | ||
30 | ||
31 | /** | |
32 | * usb_descriptor_fillbuf - fill buffer with descriptors | |
33 | * @buf: Buffer to be filled | |
34 | * @buflen: Size of buf | |
35 | * @src: Array of descriptor pointers, terminated by null pointer. | |
36 | * | |
37 | * Copies descriptors into the buffer, returning the length or a | |
38 | * negative error code if they can't all be copied. Useful when | |
39 | * assembling descriptors for an associated set of interfaces used | |
40 | * as part of configuring a composite device; or in other cases where | |
41 | * sets of descriptors need to be marshaled. | |
42 | */ | |
43 | int | |
44 | usb_descriptor_fillbuf(void *buf, unsigned buflen, | |
45 | const struct usb_descriptor_header **src) | |
46 | { | |
47 | u8 *dest = buf; | |
48 | ||
49 | if (!src) | |
50 | return -EINVAL; | |
51 | ||
52 | /* fill buffer from src[] until null descriptor ptr */ | |
53 | for (; 0 != *src; src++) { | |
54 | unsigned len = (*src)->bLength; | |
55 | ||
56 | if (len > buflen) | |
57 | return -EINVAL; | |
58 | memcpy(dest, *src, len); | |
59 | buflen -= len; | |
60 | dest += len; | |
61 | } | |
62 | return dest - (u8 *)buf; | |
63 | } | |
64 | ||
65 | ||
66 | /** | |
67 | * usb_gadget_config_buf - builts a complete configuration descriptor | |
68 | * @config: Header for the descriptor, including characteristics such | |
69 | * as power requirements and number of interfaces. | |
70 | * @desc: Null-terminated vector of pointers to the descriptors (interface, | |
71 | * endpoint, etc) defining all functions in this device configuration. | |
72 | * @buf: Buffer for the resulting configuration descriptor. | |
73 | * @length: Length of buffer. If this is not big enough to hold the | |
74 | * entire configuration descriptor, an error code will be returned. | |
75 | * | |
76 | * This copies descriptors into the response buffer, building a descriptor | |
77 | * for that configuration. It returns the buffer length or a negative | |
78 | * status code. The config.wTotalLength field is set to match the length | |
79 | * of the result, but other descriptor fields (including power usage and | |
80 | * interface count) must be set by the caller. | |
81 | * | |
82 | * Gadget drivers could use this when constructing a config descriptor | |
83 | * in response to USB_REQ_GET_DESCRIPTOR. They will need to patch the | |
84 | * resulting bDescriptorType value if USB_DT_OTHER_SPEED_CONFIG is needed. | |
85 | */ | |
86 | int usb_gadget_config_buf( | |
87 | const struct usb_config_descriptor *config, | |
88 | void *buf, | |
89 | unsigned length, | |
90 | const struct usb_descriptor_header **desc | |
91 | ) | |
92 | { | |
93 | struct usb_config_descriptor *cp = buf; | |
94 | int len; | |
95 | ||
96 | /* config descriptor first */ | |
97 | if (length < USB_DT_CONFIG_SIZE || !desc) | |
98 | return -EINVAL; | |
99 | *cp = *config; | |
100 | ||
101 | /* then interface/endpoint/class/vendor/... */ | |
102 | len = usb_descriptor_fillbuf(USB_DT_CONFIG_SIZE + (u8*)buf, | |
103 | length - USB_DT_CONFIG_SIZE, desc); | |
104 | if (len < 0) | |
105 | return len; | |
106 | len += USB_DT_CONFIG_SIZE; | |
107 | if (len > 0xffff) | |
108 | return -EINVAL; | |
109 | ||
110 | /* patch up the config descriptor */ | |
111 | cp->bLength = USB_DT_CONFIG_SIZE; | |
112 | cp->bDescriptorType = USB_DT_CONFIG; | |
113 | cp->wTotalLength = cpu_to_le16(len); | |
114 | cp->bmAttributes |= USB_CONFIG_ATT_ONE; | |
115 | return len; | |
116 | } | |
117 |