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 |
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 | */ |
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 ** |
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(size: 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 | |
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 | |
200 | void usb_free_all_descriptors(struct usb_function *f) |
201 | { |
202 | usb_free_descriptors(v: f->fs_descriptors); |
203 | f->fs_descriptors = NULL; |
204 | usb_free_descriptors(v: f->hs_descriptors); |
205 | f->hs_descriptors = NULL; |
206 | usb_free_descriptors(v: f->ss_descriptors); |
207 | f->ss_descriptors = NULL; |
208 | usb_free_descriptors(v: f->ssp_descriptors); |
209 | f->ssp_descriptors = NULL; |
210 | } |
211 | EXPORT_SYMBOL_GPL(usb_free_all_descriptors); |
212 | |
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(size: length, GFP_KERNEL); |
225 | return otg_desc; |
226 | } |
227 | EXPORT_SYMBOL_GPL(usb_otg_descriptor_alloc); |
228 | |
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 | |