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(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(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); 212 213 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); 228 229 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