1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * usb/gadget/config.c -- simplify building config descriptors
4 *
5 * Copyright (C) 2003 David Brownell
6 */
7
8 #include <linux/errno.h>
9 #include <linux/slab.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/list.h>
13 #include <linux/string.h>
14 #include <linux/device.h>
15
16 #include <linux/usb/ch9.h>
17 #include <linux/usb/gadget.h>
18 #include <linux/usb/composite.h>
19 #include <linux/usb/otg.h>
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
usb_descriptor_fillbuf(void * buf,unsigned buflen,const struct usb_descriptor_header ** src)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 EXPORT_SYMBOL_GPL(usb_descriptor_fillbuf);
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 */
usb_gadget_config_buf(const struct usb_config_descriptor * config,void * buf,unsigned length,const struct usb_descriptor_header ** desc)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/... */
92 len = usb_descriptor_fillbuf(USB_DT_CONFIG_SIZE + (u8 *)buf,
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 }
107 EXPORT_SYMBOL_GPL(usb_gadget_config_buf);
108
109 /**
110 * usb_copy_descriptors - copy a vector of USB descriptors
111 * @src: null-terminated vector to copy
112 * Context: initialization code, which may sleep
113 *
114 * This makes a copy of a vector of USB descriptors. Its primary use
115 * is to support usb_function objects which can have multiple copies,
116 * each needing different descriptors. Functions may have static
117 * tables of descriptors, which are used as templates and customized
118 * with identifiers (for interfaces, strings, endpoints, and more)
119 * as needed by a given function instance.
120 */
121 struct usb_descriptor_header **
usb_copy_descriptors(struct usb_descriptor_header ** src)122 usb_copy_descriptors(struct usb_descriptor_header **src)
123 {
124 struct usb_descriptor_header **tmp;
125 unsigned bytes;
126 unsigned n_desc;
127 void *mem;
128 struct usb_descriptor_header **ret;
129
130 /* count descriptors and their sizes; then add vector size */
131 for (bytes = 0, n_desc = 0, tmp = src; *tmp; tmp++, n_desc++)
132 bytes += (*tmp)->bLength;
133 bytes += (n_desc + 1) * sizeof(*tmp);
134
135 mem = kmalloc(bytes, GFP_KERNEL);
136 if (!mem)
137 return NULL;
138
139 /* fill in pointers starting at "tmp",
140 * to descriptors copied starting at "mem";
141 * and return "ret"
142 */
143 tmp = mem;
144 ret = mem;
145 mem += (n_desc + 1) * sizeof(*tmp);
146 while (*src) {
147 memcpy(mem, *src, (*src)->bLength);
148 *tmp = mem;
149 tmp++;
150 mem += (*src)->bLength;
151 src++;
152 }
153 *tmp = NULL;
154
155 return ret;
156 }
157 EXPORT_SYMBOL_GPL(usb_copy_descriptors);
158
usb_assign_descriptors(struct usb_function * f,struct usb_descriptor_header ** fs,struct usb_descriptor_header ** hs,struct usb_descriptor_header ** ss,struct usb_descriptor_header ** ssp)159 int usb_assign_descriptors(struct usb_function *f,
160 struct usb_descriptor_header **fs,
161 struct usb_descriptor_header **hs,
162 struct usb_descriptor_header **ss,
163 struct usb_descriptor_header **ssp)
164 {
165 /* super-speed-plus descriptor falls back to super-speed one,
166 * if such a descriptor was provided, thus avoiding a NULL
167 * pointer dereference if a 5gbps capable gadget is used with
168 * a 10gbps capable config (device port + cable + host port)
169 */
170 if (!ssp)
171 ssp = ss;
172
173 if (fs) {
174 f->fs_descriptors = usb_copy_descriptors(fs);
175 if (!f->fs_descriptors)
176 goto err;
177 }
178 if (hs) {
179 f->hs_descriptors = usb_copy_descriptors(hs);
180 if (!f->hs_descriptors)
181 goto err;
182 }
183 if (ss) {
184 f->ss_descriptors = usb_copy_descriptors(ss);
185 if (!f->ss_descriptors)
186 goto err;
187 }
188 if (ssp) {
189 f->ssp_descriptors = usb_copy_descriptors(ssp);
190 if (!f->ssp_descriptors)
191 goto err;
192 }
193 return 0;
194 err:
195 usb_free_all_descriptors(f);
196 return -ENOMEM;
197 }
198 EXPORT_SYMBOL_GPL(usb_assign_descriptors);
199
usb_free_all_descriptors(struct usb_function * f)200 void usb_free_all_descriptors(struct usb_function *f)
201 {
202 usb_free_descriptors(f->fs_descriptors);
203 f->fs_descriptors = NULL;
204 usb_free_descriptors(f->hs_descriptors);
205 f->hs_descriptors = NULL;
206 usb_free_descriptors(f->ss_descriptors);
207 f->ss_descriptors = NULL;
208 usb_free_descriptors(f->ssp_descriptors);
209 f->ssp_descriptors = NULL;
210 }
211 EXPORT_SYMBOL_GPL(usb_free_all_descriptors);
212
usb_otg_descriptor_alloc(struct usb_gadget * gadget)213 struct usb_descriptor_header *usb_otg_descriptor_alloc(
214 struct usb_gadget *gadget)
215 {
216 struct usb_descriptor_header *otg_desc;
217 unsigned length = 0;
218
219 if (gadget->otg_caps && (gadget->otg_caps->otg_rev >= 0x0200))
220 length = sizeof(struct usb_otg20_descriptor);
221 else
222 length = sizeof(struct usb_otg_descriptor);
223
224 otg_desc = kzalloc(length, GFP_KERNEL);
225 return otg_desc;
226 }
227 EXPORT_SYMBOL_GPL(usb_otg_descriptor_alloc);
228
usb_otg_descriptor_init(struct usb_gadget * gadget,struct usb_descriptor_header * otg_desc)229 int usb_otg_descriptor_init(struct usb_gadget *gadget,
230 struct usb_descriptor_header *otg_desc)
231 {
232 struct usb_otg_descriptor *otg1x_desc;
233 struct usb_otg20_descriptor *otg20_desc;
234 struct usb_otg_caps *otg_caps = gadget->otg_caps;
235 u8 otg_attributes = 0;
236
237 if (!otg_desc)
238 return -EINVAL;
239
240 if (otg_caps && otg_caps->otg_rev) {
241 if (otg_caps->hnp_support)
242 otg_attributes |= USB_OTG_HNP;
243 if (otg_caps->srp_support)
244 otg_attributes |= USB_OTG_SRP;
245 if (otg_caps->adp_support && (otg_caps->otg_rev >= 0x0200))
246 otg_attributes |= USB_OTG_ADP;
247 } else {
248 otg_attributes = USB_OTG_SRP | USB_OTG_HNP;
249 }
250
251 if (otg_caps && (otg_caps->otg_rev >= 0x0200)) {
252 otg20_desc = (struct usb_otg20_descriptor *)otg_desc;
253 otg20_desc->bLength = sizeof(struct usb_otg20_descriptor);
254 otg20_desc->bDescriptorType = USB_DT_OTG;
255 otg20_desc->bmAttributes = otg_attributes;
256 otg20_desc->bcdOTG = cpu_to_le16(otg_caps->otg_rev);
257 } else {
258 otg1x_desc = (struct usb_otg_descriptor *)otg_desc;
259 otg1x_desc->bLength = sizeof(struct usb_otg_descriptor);
260 otg1x_desc->bDescriptorType = USB_DT_OTG;
261 otg1x_desc->bmAttributes = otg_attributes;
262 }
263
264 return 0;
265 }
266 EXPORT_SYMBOL_GPL(usb_otg_descriptor_init);
267