drivers/usb/gadget/config.c

   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         struct usb_gadget *g = f->config->cdev->gadget;
 166
 167         if (fs) {
 168                 f->fs_descriptors = usb_copy_descriptors(fs);
 169                 if (!f->fs_descriptors)
 170                         goto err;
 171         }
 172         if (hs && gadget_is_dualspeed(g)) {
 173                 f->hs_descriptors = usb_copy_descriptors(hs);
 174                 if (!f->hs_descriptors)
 175                         goto err;
 176         }
 177         if (ss && gadget_is_superspeed(g)) {
 178                 f->ss_descriptors = usb_copy_descriptors(ss);
 179                 if (!f->ss_descriptors)
 180                         goto err;
 181         }
 182         if (ssp && gadget_is_superspeed_plus(g)) {
 183                 f->ssp_descriptors = usb_copy_descriptors(ssp);
 184                 if (!f->ssp_descriptors)
 185                         goto err;
 186         }
 187         return 0;
 188 err:
 189         usb_free_all_descriptors(f);
 190         return -ENOMEM;
 191 }
 192 EXPORT_SYMBOL_GPL(usb_assign_descriptors);
 193
 194 void usb_free_all_descriptors(struct usb_function *f)
 195 {
 196         usb_free_descriptors(f->fs_descriptors);
 197         usb_free_descriptors(f->hs_descriptors);
 198         usb_free_descriptors(f->ss_descriptors);
 199         usb_free_descriptors(f->ssp_descriptors);
 200 }
 201 EXPORT_SYMBOL_GPL(usb_free_all_descriptors);
 202
 203 struct usb_descriptor_header *usb_otg_descriptor_alloc(
 204                                 struct usb_gadget *gadget)
 205 {
 206         struct usb_descriptor_header *otg_desc;
 207         unsigned length = 0;
 208
 209         if (gadget->otg_caps && (gadget->otg_caps->otg_rev >= 0x0200))
 210                 length = sizeof(struct usb_otg20_descriptor);
 211         else
 212                 length = sizeof(struct usb_otg_descriptor);
 213
 214         otg_desc = kzalloc(length, GFP_KERNEL);
 215         return otg_desc;
 216 }
 217 EXPORT_SYMBOL_GPL(usb_otg_descriptor_alloc);
 218
 219 int usb_otg_descriptor_init(struct usb_gadget *gadget,
 220                 struct usb_descriptor_header *otg_desc)
 221 {
 222         struct usb_otg_descriptor *otg1x_desc;
 223         struct usb_otg20_descriptor *otg20_desc;
 224         struct usb_otg_caps *otg_caps = gadget->otg_caps;
 225         u8 otg_attributes = 0;
 226
 227         if (!otg_desc)
 228                 return -EINVAL;
 229
 230         if (otg_caps && otg_caps->otg_rev) {
 231                 if (otg_caps->hnp_support)
 232                         otg_attributes |= USB_OTG_HNP;
 233                 if (otg_caps->srp_support)
 234                         otg_attributes |= USB_OTG_SRP;
 235                 if (otg_caps->adp_support && (otg_caps->otg_rev >= 0x0200))
 236                         otg_attributes |= USB_OTG_ADP;
 237         } else {
 238                 otg_attributes = USB_OTG_SRP | USB_OTG_HNP;
 239         }
 240
 241         if (otg_caps && (otg_caps->otg_rev >= 0x0200)) {
 242                 otg20_desc = (struct usb_otg20_descriptor *)otg_desc;
 243                 otg20_desc->bLength = sizeof(struct usb_otg20_descriptor);
 244                 otg20_desc->bDescriptorType = USB_DT_OTG;
 245                 otg20_desc->bmAttributes = otg_attributes;
 246                 otg20_desc->bcdOTG = cpu_to_le16(otg_caps->otg_rev);
 247         } else {
 248                 otg1x_desc = (struct usb_otg_descriptor *)otg_desc;
 249                 otg1x_desc->bLength = sizeof(struct usb_otg_descriptor);
 250                 otg1x_desc->bDescriptorType = USB_DT_OTG;
 251                 otg1x_desc->bmAttributes = otg_attributes;
 252         }
 253
 254         return 0;
 255 }
 256 EXPORT_SYMBOL_GPL(usb_otg_descriptor_init);