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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> |
9454a57a | 28 | #include <linux/usb/gadget.h> |
1da177e4 LT |
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 */ | |
a9475226 | 53 | for (; NULL != *src; src++) { |
1da177e4 LT |
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; | |
a4c39c41 | 99 | *cp = *config; |
1da177e4 LT |
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 | ||
a4c39c41 DB |
118 | /** |
119 | * usb_copy_descriptors - copy a vector of USB descriptors | |
120 | * @src: null-terminated vector to copy | |
121 | * Context: initialization code, which may sleep | |
122 | * | |
123 | * This makes a copy of a vector of USB descriptors. Its primary use | |
124 | * is to support usb_function objects which can have multiple copies, | |
125 | * each needing different descriptors. Functions may have static | |
126 | * tables of descriptors, which are used as templates and customized | |
127 | * with identifiers (for interfaces, strings, endpoints, and more) | |
128 | * as needed by a given function instance. | |
129 | */ | |
130 | struct usb_descriptor_header **__init | |
131 | usb_copy_descriptors(struct usb_descriptor_header **src) | |
132 | { | |
133 | struct usb_descriptor_header **tmp; | |
134 | unsigned bytes; | |
135 | unsigned n_desc; | |
136 | void *mem; | |
137 | struct usb_descriptor_header **ret; | |
138 | ||
139 | /* count descriptors and their sizes; then add vector size */ | |
140 | for (bytes = 0, n_desc = 0, tmp = src; *tmp; tmp++, n_desc++) | |
141 | bytes += (*tmp)->bLength; | |
142 | bytes += (n_desc + 1) * sizeof(*tmp); | |
143 | ||
144 | mem = kmalloc(bytes, GFP_KERNEL); | |
145 | if (!mem) | |
146 | return NULL; | |
147 | ||
148 | /* fill in pointers starting at "tmp", | |
149 | * to descriptors copied starting at "mem"; | |
150 | * and return "ret" | |
151 | */ | |
152 | tmp = mem; | |
153 | ret = mem; | |
154 | mem += (n_desc + 1) * sizeof(*tmp); | |
155 | while (*src) { | |
156 | memcpy(mem, *src, (*src)->bLength); | |
157 | *tmp = mem; | |
158 | tmp++; | |
159 | mem += (*src)->bLength; | |
160 | src++; | |
161 | } | |
162 | *tmp = NULL; | |
163 | ||
164 | return ret; | |
165 | } | |
166 | ||
167 | /** | |
168 | * usb_find_endpoint - find a copy of an endpoint descriptor | |
169 | * @src: original vector of descriptors | |
170 | * @copy: copy of @src | |
dd9ebf14 | 171 | * @match: endpoint descriptor found in @src |
a4c39c41 DB |
172 | * |
173 | * This returns the copy of the @match descriptor made for @copy. Its | |
174 | * intended use is to help remembering the endpoint descriptor to use | |
175 | * when enabling a given endpoint. | |
176 | */ | |
177 | struct usb_endpoint_descriptor *__init | |
178 | usb_find_endpoint( | |
179 | struct usb_descriptor_header **src, | |
180 | struct usb_descriptor_header **copy, | |
181 | struct usb_endpoint_descriptor *match | |
182 | ) | |
183 | { | |
184 | while (*src) { | |
185 | if (*src == (void *) match) | |
186 | return (void *)*copy; | |
187 | src++; | |
188 | copy++; | |
189 | } | |
190 | return NULL; | |
191 | } |