usb.c

是关于linux2.5.1的完全源码

	unsigned char *begin;
	int parsed = 0, len, numskipped;

	header = (struct usb_descriptor_header *)buffer;

	/* Everything should be fine being passed into here, but we sanity */
	/*  check JIC */
	if (header->bLength > size) {
		err("ran out of descriptors parsing");
		return -1;
	}
		
	if (header->bDescriptorType != USB_DT_ENDPOINT) {
		warn("unexpected descriptor 0x%X, expecting endpoint descriptor, type 0x%X",
			endpoint->bDescriptorType, USB_DT_ENDPOINT);
		return parsed;
	}

	if (header->bLength == USB_DT_ENDPOINT_AUDIO_SIZE)
		memcpy(endpoint, buffer, USB_DT_ENDPOINT_AUDIO_SIZE);
	else
		memcpy(endpoint, buffer, USB_DT_ENDPOINT_SIZE);
	
	le16_to_cpus(&endpoint->wMaxPacketSize);

	buffer += header->bLength;
	size -= header->bLength;
	parsed += header->bLength;

	/* Skip over the rest of the Class Specific or Vendor Specific */
	/*  descriptors */
	begin = buffer;
	numskipped = 0;
	while (size >= sizeof(struct usb_descriptor_header)) {
		header = (struct usb_descriptor_header *)buffer;

		if (header->bLength < 2) {
			err("invalid descriptor length of %d", header->bLength);
			return -1;
		}

		/* If we find another "proper" descriptor then we're done  */
		if ((header->bDescriptorType == USB_DT_ENDPOINT) ||
		    (header->bDescriptorType == USB_DT_INTERFACE) ||
		    (header->bDescriptorType == USB_DT_CONFIG) ||
		    (header->bDescriptorType == USB_DT_DEVICE))
			break;

		dbg("skipping descriptor 0x%X",
			header->bDescriptorType);
		numskipped++;

		buffer += header->bLength;
		size -= header->bLength;
		parsed += header->bLength;
	}
	if (numskipped)
		dbg("skipped %d class/vendor specific endpoint descriptors", numskipped);

	/* Copy any unknown descriptors into a storage area for drivers */
	/*  to later parse */
	len = (int)(buffer - begin);
	if (!len) {
		endpoint->extra = NULL;
		endpoint->extralen = 0;
		return parsed;
	}

	endpoint->extra = kmalloc(len, GFP_KERNEL);

	if (!endpoint->extra) {
		err("couldn't allocate memory for endpoint extra descriptors");
		endpoint->extralen = 0;
		return parsed;
	}

	memcpy(endpoint->extra, begin, len);
	endpoint->extralen = len;

	return parsed;
}

static int usb_parse_interface(struct usb_interface *interface, unsigned char *buffer, int size)
{
	int i, len, numskipped, retval, parsed = 0;
	struct usb_descriptor_header *header;
	struct usb_interface_descriptor *ifp;
	unsigned char *begin;

	interface->act_altsetting = 0;
	interface->num_altsetting = 0;
	interface->max_altsetting = USB_ALTSETTINGALLOC;

	interface->altsetting = kmalloc(sizeof(struct usb_interface_descriptor) * interface->max_altsetting, GFP_KERNEL);
	
	if (!interface->altsetting) {
		err("couldn't kmalloc interface->altsetting");
		return -1;
	}

	while (size > 0) {
		if (interface->num_altsetting >= interface->max_altsetting) {
			void *ptr;
			int oldmas;

			oldmas = interface->max_altsetting;
			interface->max_altsetting += USB_ALTSETTINGALLOC;
			if (interface->max_altsetting > USB_MAXALTSETTING) {
				warn("too many alternate settings (max %d)",
					USB_MAXALTSETTING);
				return -1;
			}

			ptr = interface->altsetting;
			interface->altsetting = kmalloc(sizeof(struct usb_interface_descriptor) * interface->max_altsetting, GFP_KERNEL);
			if (!interface->altsetting) {
				err("couldn't kmalloc interface->altsetting");
				interface->altsetting = ptr;
				return -1;
			}
			memcpy(interface->altsetting, ptr, sizeof(struct usb_interface_descriptor) * oldmas);

			kfree(ptr);
		}

		ifp = interface->altsetting + interface->num_altsetting;
		ifp->endpoint = NULL;
		ifp->extra = NULL;
		ifp->extralen = 0;
		interface->num_altsetting++;

		memcpy(ifp, buffer, USB_DT_INTERFACE_SIZE);

		/* Skip over the interface */
		buffer += ifp->bLength;
		parsed += ifp->bLength;
		size -= ifp->bLength;

		begin = buffer;
		numskipped = 0;

		/* Skip over any interface, class or vendor descriptors */
		while (size >= sizeof(struct usb_descriptor_header)) {
			header = (struct usb_descriptor_header *)buffer;

			if (header->bLength < 2) {
				err("invalid descriptor length of %d", header->bLength);
				return -1;
			}

			/* If we find another "proper" descriptor then we're done  */
			if ((header->bDescriptorType == USB_DT_INTERFACE) ||
			    (header->bDescriptorType == USB_DT_ENDPOINT) ||
			    (header->bDescriptorType == USB_DT_CONFIG) ||
			    (header->bDescriptorType == USB_DT_DEVICE))
				break;

			numskipped++;

			buffer += header->bLength;
			parsed += header->bLength;
			size -= header->bLength;
		}

		if (numskipped)
			dbg("skipped %d class/vendor specific interface descriptors", numskipped);

		/* Copy any unknown descriptors into a storage area for */
		/*  drivers to later parse */
		len = (int)(buffer - begin);
		if (len) {
			ifp->extra = kmalloc(len, GFP_KERNEL);

			if (!ifp->extra) {
				err("couldn't allocate memory for interface extra descriptors");
				ifp->extralen = 0;
				return -1;
			}
			memcpy(ifp->extra, begin, len);
			ifp->extralen = len;
		}

		/* Did we hit an unexpected descriptor? */
		header = (struct usb_descriptor_header *)buffer;
		if ((size >= sizeof(struct usb_descriptor_header)) &&
		    ((header->bDescriptorType == USB_DT_CONFIG) ||
		     (header->bDescriptorType == USB_DT_DEVICE)))
			return parsed;

		if (ifp->bNumEndpoints > USB_MAXENDPOINTS) {
			warn("too many endpoints");
			return -1;
		}

		ifp->endpoint = (struct usb_endpoint_descriptor *)
			kmalloc(ifp->bNumEndpoints *
			sizeof(struct usb_endpoint_descriptor), GFP_KERNEL);
		if (!ifp->endpoint) {
			err("out of memory");
			return -1;	
		}

		memset(ifp->endpoint, 0, ifp->bNumEndpoints *
			sizeof(struct usb_endpoint_descriptor));
	
		for (i = 0; i < ifp->bNumEndpoints; i++) {
			header = (struct usb_descriptor_header *)buffer;

			if (header->bLength > size) {
				err("ran out of descriptors parsing");
				return -1;
			}
		
			retval = usb_parse_endpoint(ifp->endpoint + i, buffer, size);
			if (retval < 0)
				return retval;

			buffer += retval;
			parsed += retval;
			size -= retval;
		}

		/* We check to see if it's an alternate to this one */
		ifp = (struct usb_interface_descriptor *)buffer;
		if (size < USB_DT_INTERFACE_SIZE ||
		    ifp->bDescriptorType != USB_DT_INTERFACE ||
		    !ifp->bAlternateSetting)
			return parsed;
	}

	return parsed;
}

int usb_parse_configuration(struct usb_config_descriptor *config, char *buffer)
{
	int i, retval, size;
	struct usb_descriptor_header *header;

	memcpy(config, buffer, USB_DT_CONFIG_SIZE);
	le16_to_cpus(&config->wTotalLength);
	size = config->wTotalLength;

	if (config->bNumInterfaces > USB_MAXINTERFACES) {
		warn("too many interfaces");
		return -1;
	}

	config->interface = (struct usb_interface *)
		kmalloc(config->bNumInterfaces *
		sizeof(struct usb_interface), GFP_KERNEL);
	dbg("kmalloc IF %p, numif %i", config->interface, config->bNumInterfaces);
	if (!config->interface) {
		err("out of memory");
		return -1;	
	}

	memset(config->interface, 0,
	       config->bNumInterfaces * sizeof(struct usb_interface));

	buffer += config->bLength;
	size -= config->bLength;
	
	config->extra = NULL;
	config->extralen = 0;

	for (i = 0; i < config->bNumInterfaces; i++) {
		int numskipped, len;
		char *begin;

		/* Skip over the rest of the Class Specific or Vendor */
		/*  Specific descriptors */
		begin = buffer;
		numskipped = 0;
		while (size >= sizeof(struct usb_descriptor_header)) {
			header = (struct usb_descriptor_header *)buffer;

			if ((header->bLength > size) || (header->bLength < 2)) {
				err("invalid descriptor length of %d", header->bLength);
				return -1;
			}

			/* If we find another "proper" descriptor then we're done  */
			if ((header->bDescriptorType == USB_DT_ENDPOINT) ||
			    (header->bDescriptorType == USB_DT_INTERFACE) ||
			    (header->bDescriptorType == USB_DT_CONFIG) ||
			    (header->bDescriptorType == USB_DT_DEVICE))
				break;

			dbg("skipping descriptor 0x%X", header->bDescriptorType);
			numskipped++;

			buffer += header->bLength;
			size -= header->bLength;
		}
		if (numskipped)
			dbg("skipped %d class/vendor specific endpoint descriptors", numskipped);

		/* Copy any unknown descriptors into a storage area for */
		/*  drivers to later parse */
		len = (int)(buffer - begin);
		if (len) {
			if (config->extralen) {
				warn("extra config descriptor");
			} else {
				config->extra = kmalloc(len, GFP_KERNEL);
				if (!config->extra) {
					err("couldn't allocate memory for config extra descriptors");
					config->extralen = 0;
					return -1;
				}

				memcpy(config->extra, begin, len);
				config->extralen = len;
			}
		}

		retval = usb_parse_interface(config->interface + i, buffer, size);
		if (retval < 0)
			return retval;

		buffer += retval;
		size -= retval;
	}

	return size;
}

// 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, j, k;
	
	if (!dev->config)
		return;

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

		kfree(dev->rawdescriptors);
	}

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

		if (!cf->interface)
			break;

		for (i = 0; i < cf->bNumInterfaces; i++) {
			struct usb_interface *ifp =
				&cf->interface[i];
				
			if (!ifp->altsetting)
				break;

			for (j = 0; j < ifp->num_altsetting; j++) {
				struct usb_interface_descriptor *as =
					&ifp->altsetting[j];
					
				if(as->extra) {
					kfree(as->extra);
				}

				if (!as->endpoint)
					break;
					
				for(k = 0; k < as->bNumEndpoints; k++) {
					if(as->endpoint[k].extra) {
						kfree(as->endpoint[k].extra);
					}
				}	
				kfree(as->endpoint);
			}

			kfree(ifp->altsetting);
		}
		kfree(cf->interface);
	}
	kfree(dev->config);
}

/* for returning string descriptors in UTF-16LE */
static int ascii2utf (char *ascii, __u8 *utf, int utfmax)
{
	int retval;

	for (retval = 0; *ascii && utfmax > 1; utfmax -= 2, retval += 2) {
		*utf++ = *ascii++ & 0x7f;
		*utf++ = 0;
	}
	return retval;
}

/*
 * root_hub_string is used by each host controller's root hub code,
 * so that they're identified consistently throughout the system.
 */
int usb_root_hub_string (int id, int serial, char *type, __u8 *data, int len)
{
	char buf [30];

	// assert (len > (2 * (sizeof (buf) + 1)));
	// assert (strlen (type) <= 8);

	// language ids
	if (id == 0) {
		*data++ = 4; *data++ = 3;	/* 4 bytes data */
		*data++ = 0; *data++ = 0;	/* some language id */
		return 4;

	// serial number
	} else if (id == 1) {
		sprintf (buf, "%x", serial);

	// product description
	} else if (id == 2) {
		sprintf (buf, "USB %s Root Hub", type);

	// id 3 == vendor description

	// unsupported IDs --> "stall"
	} else
	    return 0;

	data [0] = 2 + ascii2utf (buf, data + 2, len - 2);