drivers/usb/gadget/config.c

   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
  12 #include <linux/errno.h>
  13 #include <linux/slab.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/list.h>
  17 #include <linux/string.h>
  18 #include <linux/device.h>
  19
  20 #include <linux/usb/ch9.h>
  21 #include <linux/usb/gadget.h>
  22 #include <linux/usb/composite.h>
  23 #include <linux/usb/otg.h>
  24
  25 /**
  26  * usb_descriptor_fillbuf - fill buffer with descriptors
  27  * @buf: Buffer to be filled
  28  * @buflen: Size of buf
  29  * @src: Array of descriptor pointers, terminated by null pointer.
  30  *
  31  * Copies descriptors into the buffer, returning the length or a
  32  * negative error code if they can't all be copied.  Useful when
  33  * assembling descriptors for an associated set of interfaces used
  34  * as part of configuring a composite device; or in other cases where
  35  * sets of descriptors need to be marshaled.
  36  */
  37 int
  38 usb_descriptor_fillbuf(void *buf, unsigned buflen,
  39                 const struct usb_descriptor_header **src)
  40 {
  41         u8      *dest = buf;
  42
  43         if (!src)
  44                 return -EINVAL;
  45
  46         /* fill buffer from src[] until null descriptor ptr */
  47         for (; NULL != *src; src++) {
  48                 unsigned                len = (*src)->bLength;
  49
  50                 if (len > buflen)
  51                         return -EINVAL;
  52                 memcpy(dest, *src, len);
  53                 buflen -= len;
  54                 dest += len;
  55         }
  56         return dest - (u8 *)buf;
  57 }
  58 EXPORT_SYMBOL_GPL(usb_descriptor_fillbuf);
  59
  60 /**
  61  * usb_gadget_config_buf - builts a complete configuration descriptor
  62  * @config: Header for the descriptor, including characteristics such
  63  *      as power requirements and number of interfaces.
  64  * @desc: Null-terminated vector of pointers to the descriptors (interface,
  65  *      endpoint, etc) defining all functions in this device configuration.
  66  * @buf: Buffer for the resulting configuration descriptor.
  67  * @length: Length of buffer.  If this is not big enough to hold the
  68  *      entire configuration descriptor, an error code will be returned.
  69  *
  70  * This copies descriptors into the response buffer, building a descriptor
  71  * for that configuration.  It returns the buffer length or a negative
  72  * status code.  The config.wTotalLength field is set to match the length
  73  * of the result, but other descriptor fields (including power usage and
  74  * interface count) must be set by the caller.
  75  *
  76  * Gadget drivers could use this when constructing a config descriptor
  77  * in response to USB_REQ_GET_DESCRIPTOR.  They will need to patch the
  78  * resulting bDescriptorType value if USB_DT_OTHER_SPEED_CONFIG is needed.
  79  */
  80 int usb_gadget_config_buf(
  81         const struct usb_config_descriptor      *config,
  82         void                                    *buf,
  83         unsigned                                length,
  84         const struct usb_descriptor_header      **desc
  85 )
  86 {
  87         struct usb_config_descriptor            *cp = buf;
  88         int                                     len;
  89
  90         /* config descriptor first */
  91         if (length < USB_DT_CONFIG_SIZE || !desc)
  92                 return -EINVAL;
  93         *cp = *config;
  94
  95         /* then interface/endpoint/class/vendor/... */
  96         len = usb_descriptor_fillbuf(USB_DT_CONFIG_SIZE + (u8*)buf,
  97                         length - USB_DT_CONFIG_SIZE, desc);
  98         if (len < 0)
  99                 return len;
 100         len += USB_DT_CONFIG_SIZE;
 101         if (len > 0xffff)
 102                 return -EINVAL;
 103
 104         /* patch up the config descriptor */
 105         cp->bLength = USB_DT_CONFIG_SIZE;
 106         cp->bDescriptorType = USB_DT_CONFIG;
 107         cp->wTotalLength = cpu_to_le16(len);
 108         cp->bmAttributes |= USB_CONFIG_ATT_ONE;
 109         return len;
 110 }
 111 EXPORT_SYMBOL_GPL(usb_gadget_config_buf);
 112
 113 /**
 114  * usb_copy_descriptors - copy a vector of USB descriptors
 115  * @src: null-terminated vector to copy
 116  * Context: initialization code, which may sleep
 117  *
 118  * This makes a copy of a vector of USB descriptors.  Its primary use
 119  * is to support usb_function objects which can have multiple copies,
 120  * each needing different descriptors.  Functions may have static
 121  * tables of descriptors, which are used as templates and customized
 122  * with identifiers (for interfaces, strings, endpoints, and more)
 123  * as needed by a given function instance.
 124  */
 125 struct usb_descriptor_header **
 126 usb_copy_descriptors(struct usb_descriptor_header **src)
 127 {
 128         struct usb_descriptor_header **tmp;
 129         unsigned bytes;
 130         unsigned n_desc;
 131         void *mem;
 132         struct usb_descriptor_header **ret;
 133
 134         /* count descriptors and their sizes; then add vector size */
 135         for (bytes = 0, n_desc = 0, tmp = src; *tmp; tmp++, n_desc++)
 136                 bytes += (*tmp)->bLength;
 137         bytes += (n_desc + 1) * sizeof(*tmp);
 138
 139         mem = kmalloc(bytes, GFP_KERNEL);
 140         if (!mem)
 141                 return NULL;
 142
 143         /* fill in pointers starting at "tmp",
 144          * to descriptors copied starting at "mem";
 145          * and return "ret"
 146          */
 147         tmp = mem;
 148         ret = mem;
 149         mem += (n_desc + 1) * sizeof(*tmp);
 150         while (*src) {
 151                 memcpy(mem, *src, (*src)->bLength);
 152                 *tmp = mem;
 153                 tmp++;
 154                 mem += (*src)->bLength;
 155                 src++;
 156         }
 157         *tmp = NULL;
 158
 159         return ret;
 160 }
 161 EXPORT_SYMBOL_GPL(usb_copy_descriptors);
 162
 163 int usb_assign_descriptors(struct usb_function *f,
 164                 struct usb_descriptor_header **fs,
 165                 struct usb_descriptor_header **hs,
 166                 struct usb_descriptor_header **ss)
 167 {
 168         struct usb_gadget *g = f->config->cdev->gadget;
 169
 170         if (fs) {
 171                 f->fs_descriptors = usb_copy_descriptors(fs);
 172                 if (!f->fs_descriptors)
 173                         goto err;
 174         }
 175         if (hs && gadget_is_dualspeed(g)) {
 176                 f->hs_descriptors = usb_copy_descriptors(hs);
 177                 if (!f->hs_descriptors)
 178                         goto err;
 179         }
 180         if (ss && gadget_is_superspeed(g)) {
 181                 f->ss_descriptors = usb_copy_descriptors(ss);
 182                 if (!f->ss_descriptors)
 183                         goto err;
 184         }
 185         return 0;
 186 err:
 187         usb_free_all_descriptors(f);
 188         return -ENOMEM;
 189 }
 190 EXPORT_SYMBOL_GPL(usb_assign_descriptors);
 191
 192 void usb_free_all_descriptors(struct usb_function *f)
 193 {
 194         usb_free_descriptors(f->fs_descriptors);
 195         usb_free_descriptors(f->hs_descriptors);
 196         usb_free_descriptors(f->ss_descriptors);
 197 }
 198 EXPORT_SYMBOL_GPL(usb_free_all_descriptors);
 199
 200 struct usb_descriptor_header *usb_otg_descriptor_alloc(
 201                                 struct usb_gadget *gadget)
 202 {
 203         struct usb_descriptor_header *otg_desc;
 204         unsigned length = 0;
 205
 206         if (gadget->otg_caps && (gadget->otg_caps->otg_rev >= 0x0200))
 207                 length = sizeof(struct usb_otg20_descriptor);
 208         else
 209                 length = sizeof(struct usb_otg_descriptor);
 210
 211         otg_desc = kzalloc(length, GFP_KERNEL);
 212         return otg_desc;
 213 }
 214 EXPORT_SYMBOL_GPL(usb_otg_descriptor_alloc);
 215
 216 int usb_otg_descriptor_init(struct usb_gadget *gadget,
 217                 struct usb_descriptor_header *otg_desc)
 218 {
 219         struct usb_otg_descriptor *otg1x_desc;
 220         struct usb_otg20_descriptor *otg20_desc;
 221         struct usb_otg_caps *otg_caps = gadget->otg_caps;
 222         u8 otg_attributes = 0;
 223
 224         if (!otg_desc)
 225                 return -EINVAL;
 226
 227         if (otg_caps && otg_caps->otg_rev) {
 228                 if (otg_caps->hnp_support)
 229                         otg_attributes |= USB_OTG_HNP;
 230                 if (otg_caps->srp_support)
 231                         otg_attributes |= USB_OTG_SRP;
 232                 if (otg_caps->adp_support && (otg_caps->otg_rev >= 0x0200))
 233                         otg_attributes |= USB_OTG_ADP;
 234         } else {
 235                 otg_attributes = USB_OTG_SRP | USB_OTG_HNP;
 236         }
 237
 238         if (otg_caps && (otg_caps->otg_rev >= 0x0200)) {
 239                 otg20_desc = (struct usb_otg20_descriptor *)otg_desc;
 240                 otg20_desc->bLength = sizeof(struct usb_otg20_descriptor);
 241                 otg20_desc->bDescriptorType = USB_DT_OTG;
 242                 otg20_desc->bmAttributes = otg_attributes;
 243                 otg20_desc->bcdOTG = cpu_to_le16(otg_caps->otg_rev);
 244         } else {
 245                 otg1x_desc = (struct usb_otg_descriptor *)otg_desc;
 246                 otg1x_desc->bLength = sizeof(struct usb_otg_descriptor);
 247                 otg1x_desc->bDescriptorType = USB_DT_OTG;
 248                 otg1x_desc->bmAttributes = otg_attributes;
 249         }
 250
 251         return 0;
 252 }
 253 EXPORT_SYMBOL_GPL(usb_otg_descriptor_init);