in core/config.c [605:820]
static int usb_parse_configuration(struct usb_device *dev, int cfgidx,
struct usb_host_config *config, unsigned char *buffer, int size)
{
struct device *ddev = &dev->dev;
unsigned char *buffer0 = buffer;
int cfgno;
int nintf, nintf_orig;
int i, j, n;
struct usb_interface_cache *intfc;
unsigned char *buffer2;
int size2;
struct usb_descriptor_header *header;
int retval;
u8 inums[USB_MAXINTERFACES], nalts[USB_MAXINTERFACES];
unsigned iad_num = 0;
memcpy(&config->desc, buffer, USB_DT_CONFIG_SIZE);
nintf = nintf_orig = config->desc.bNumInterfaces;
config->desc.bNumInterfaces = 0; // Adjusted later
if (config->desc.bDescriptorType != USB_DT_CONFIG ||
config->desc.bLength < USB_DT_CONFIG_SIZE ||
config->desc.bLength > size) {
dev_err(ddev, "invalid descriptor for config index %d: "
"type = 0x%X, length = %d\n", cfgidx,
config->desc.bDescriptorType, config->desc.bLength);
return -EINVAL;
}
cfgno = config->desc.bConfigurationValue;
buffer += config->desc.bLength;
size -= config->desc.bLength;
if (nintf > USB_MAXINTERFACES) {
dev_warn(ddev, "config %d has too many interfaces: %d, "
"using maximum allowed: %d\n",
cfgno, nintf, USB_MAXINTERFACES);
nintf = USB_MAXINTERFACES;
}
/* Go through the descriptors, checking their length and counting the
* number of altsettings for each interface */
n = 0;
for ((buffer2 = buffer, size2 = size);
size2 > 0;
(buffer2 += header->bLength, size2 -= header->bLength)) {
if (size2 < sizeof(struct usb_descriptor_header)) {
dev_warn(ddev, "config %d descriptor has %d excess "
"byte%s, ignoring\n",
cfgno, size2, plural(size2));
break;
}
header = (struct usb_descriptor_header *) buffer2;
if ((header->bLength > size2) || (header->bLength < 2)) {
dev_warn(ddev, "config %d has an invalid descriptor "
"of length %d, skipping remainder of the config\n",
cfgno, header->bLength);
break;
}
if (header->bDescriptorType == USB_DT_INTERFACE) {
struct usb_interface_descriptor *d;
int inum;
d = (struct usb_interface_descriptor *) header;
if (d->bLength < USB_DT_INTERFACE_SIZE) {
dev_warn(ddev, "config %d has an invalid "
"interface descriptor of length %d, "
"skipping\n", cfgno, d->bLength);
continue;
}
inum = d->bInterfaceNumber;
if ((dev->quirks & USB_QUIRK_HONOR_BNUMINTERFACES) &&
n >= nintf_orig) {
dev_warn(ddev, "config %d has more interface "
"descriptors, than it declares in "
"bNumInterfaces, ignoring interface "
"number: %d\n", cfgno, inum);
continue;
}
if (inum >= nintf_orig)
dev_warn(ddev, "config %d has an invalid "
"interface number: %d but max is %d\n",
cfgno, inum, nintf_orig - 1);
/* Have we already encountered this interface?
* Count its altsettings */
for (i = 0; i < n; ++i) {
if (inums[i] == inum)
break;
}
if (i < n) {
if (nalts[i] < 255)
++nalts[i];
} else if (n < USB_MAXINTERFACES) {
inums[n] = inum;
nalts[n] = 1;
++n;
}
} else if (header->bDescriptorType ==
USB_DT_INTERFACE_ASSOCIATION) {
struct usb_interface_assoc_descriptor *d;
d = (struct usb_interface_assoc_descriptor *)header;
if (d->bLength < USB_DT_INTERFACE_ASSOCIATION_SIZE) {
dev_warn(ddev,
"config %d has an invalid interface association descriptor of length %d, skipping\n",
cfgno, d->bLength);
continue;
}
if (iad_num == USB_MAXIADS) {
dev_warn(ddev, "found more Interface "
"Association Descriptors "
"than allocated for in "
"configuration %d\n", cfgno);
} else {
config->intf_assoc[iad_num] = d;
iad_num++;
}
} else if (header->bDescriptorType == USB_DT_DEVICE ||
header->bDescriptorType == USB_DT_CONFIG)
dev_warn(ddev, "config %d contains an unexpected "
"descriptor of type 0x%X, skipping\n",
cfgno, header->bDescriptorType);
} /* for ((buffer2 = buffer, size2 = size); ...) */
size = buffer2 - buffer;
config->desc.wTotalLength = cpu_to_le16(buffer2 - buffer0);
if (n != nintf)
dev_warn(ddev, "config %d has %d interface%s, different from "
"the descriptor's value: %d\n",
cfgno, n, plural(n), nintf_orig);
else if (n == 0)
dev_warn(ddev, "config %d has no interfaces?\n", cfgno);
config->desc.bNumInterfaces = nintf = n;
/* Check for missing interface numbers */
for (i = 0; i < nintf; ++i) {
for (j = 0; j < nintf; ++j) {
if (inums[j] == i)
break;
}
if (j >= nintf)
dev_warn(ddev, "config %d has no interface number "
"%d\n", cfgno, i);
}
/* Allocate the usb_interface_caches and altsetting arrays */
for (i = 0; i < nintf; ++i) {
j = nalts[i];
if (j > USB_MAXALTSETTING) {
dev_warn(ddev, "too many alternate settings for "
"config %d interface %d: %d, "
"using maximum allowed: %d\n",
cfgno, inums[i], j, USB_MAXALTSETTING);
nalts[i] = j = USB_MAXALTSETTING;
}
intfc = kzalloc(struct_size(intfc, altsetting, j), GFP_KERNEL);
config->intf_cache[i] = intfc;
if (!intfc)
return -ENOMEM;
kref_init(&intfc->ref);
}
/* FIXME: parse the BOS descriptor */
/* Skip over any Class Specific or Vendor Specific descriptors;
* find the first interface descriptor */
config->extra = buffer;
i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
USB_DT_INTERFACE, &n);
config->extralen = i;
if (n > 0)
dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
n, plural(n), "configuration");
buffer += i;
size -= i;
/* Parse all the interface/altsetting descriptors */
while (size > 0) {
retval = usb_parse_interface(ddev, cfgno, config,
buffer, size, inums, nalts);
if (retval < 0)
return retval;
buffer += retval;
size -= retval;
}
/* Check for missing altsettings */
for (i = 0; i < nintf; ++i) {
intfc = config->intf_cache[i];
for (j = 0; j < intfc->num_altsetting; ++j) {
for (n = 0; n < intfc->num_altsetting; ++n) {
if (intfc->altsetting[n].desc.
bAlternateSetting == j)
break;
}
if (n >= intfc->num_altsetting)
dev_warn(ddev, "config %d interface %d has no "
"altsetting %d\n", cfgno, inums[i], j);
}
}
return 0;
}