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
27 #include <linux/usb/ch9.h>
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 (; NULL != *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
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
171 * @match: endpoint descriptor found in @src
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 }
192
|
This page was automatically generated by the
LXR engine.
|