config.c

来自「omap3 linux 2.6 用nocc去除了冗余代码」· C语言 代码 · 共 572 行 · 第 1/2 页

	buffer += config->desc.bLength;
	size -= config->desc.bLength;

	nintf = nintf_orig = config->desc.bNumInterfaces;
	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 (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_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;
		}

		len = sizeof(*intfc) + sizeof(struct usb_host_interface) * j;
		config->intf_cache[i] = intfc = kzalloc(len, GFP_KERNEL);
		if (!intfc)
			return -ENOMEM;
		kref_init(&intfc->ref);
	}

	/* 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;
}

// hub-only!! ... and only exported for reset/reinit path.
// otherwise used internally on disconnect/destroy path
void usb_destroy_configuration(struct usb_device *dev)
{
	int c, i;

	if (!dev->config)
		return;

	if (dev->rawdescriptors) {
		for (i = 0; i < dev->descriptor.bNumConfigurations; i++)
			kfree(dev->rawdescriptors[i]);

		kfree(dev->rawdescriptors);
		dev->rawdescriptors = NULL;
	}

	for (c = 0; c < dev->descriptor.bNumConfigurations; c++) {
		struct usb_host_config *cf = &dev->config[c];

		kfree(cf->string);
		for (i = 0; i < cf->desc.bNumInterfaces; i++) {
			if (cf->intf_cache[i])
				kref_put(&cf->intf_cache[i]->ref, 
					  usb_release_interface_cache);
		}
	}
	kfree(dev->config);
	dev->config = NULL;
}


// hub-only!! ... and only in reset path, or usb_new_device()
// (used by real hubs and virtual root hubs)
int usb_get_configuration(struct usb_device *dev)
{
	struct device *ddev = &dev->dev;
	int ncfg = dev->descriptor.bNumConfigurations;
	int result = -ENOMEM;
	unsigned int cfgno, length;
	unsigned char *buffer;
	unsigned char *bigbuffer;
 	struct usb_config_descriptor *desc;

	if (ncfg > USB_MAXCONFIG) {
		dev_warn(ddev, "too many configurations: %d, "
		    "using maximum allowed: %d\n", ncfg, USB_MAXCONFIG);
		dev->descriptor.bNumConfigurations = ncfg = USB_MAXCONFIG;
	}

	if (ncfg < 1) {
		dev_err(ddev, "no configurations\n");
		return -EINVAL;
	}

	length = ncfg * sizeof(struct usb_host_config);
	dev->config = kzalloc(length, GFP_KERNEL);
	if (!dev->config)
		goto err2;

	length = ncfg * sizeof(char *);
	dev->rawdescriptors = kzalloc(length, GFP_KERNEL);
	if (!dev->rawdescriptors)
		goto err2;

	buffer = kmalloc(USB_DT_CONFIG_SIZE, GFP_KERNEL);
	if (!buffer)
		goto err2;
	desc = (struct usb_config_descriptor *)buffer;

	for (cfgno = 0; cfgno < ncfg; cfgno++) {
		/* We grab just the first descriptor so we know how long
		 * the whole configuration is */
		result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
		    buffer, USB_DT_CONFIG_SIZE);
		if (result < 0) {
			dev_err(ddev, "unable to read config index %d "
			    "descriptor/%s\n", cfgno, "start");
			dev_err(ddev, "chopping to %d config(s)\n", cfgno);
			dev->descriptor.bNumConfigurations = cfgno;
			break;
		} else if (result < 4) {
			dev_err(ddev, "config index %d descriptor too short "
			    "(expected %i, got %i)\n", cfgno,
			    USB_DT_CONFIG_SIZE, result);
			result = -EINVAL;
			goto err;
		}
		length = max((int) le16_to_cpu(desc->wTotalLength),
		    USB_DT_CONFIG_SIZE);

		/* Now that we know the length, get the whole thing */
		bigbuffer = kmalloc(length, GFP_KERNEL);
		if (!bigbuffer) {
			result = -ENOMEM;
			goto err;
		}
		result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
		    bigbuffer, length);
		if (result < 0) {
			dev_err(ddev, "unable to read config index %d "
			    "descriptor/%s\n", cfgno, "all");
			kfree(bigbuffer);
			goto err;
		}
		if (result < length) {
			dev_warn(ddev, "config index %d descriptor too short "
			    "(expected %i, got %i)\n", cfgno, length, result);
			length = result;
		}

		dev->rawdescriptors[cfgno] = bigbuffer;

		result = usb_parse_configuration(&dev->dev, cfgno,
		    &dev->config[cfgno], bigbuffer, length);
		if (result < 0) {
			++cfgno;
			goto err;
		}
	}
	result = 0;

err:
	kfree(buffer);
	dev->descriptor.bNumConfigurations = cfgno;
err2:
	if (result == -ENOMEM)
		dev_err(ddev, "out of memory\n");
	return result;
}