message.c

来自「linux 内核源代码」· C语言 代码 · 共 1,699 行 · 第 1/4 页

 *
 * Returns zero on success, else a negative error code.
 */
int usb_reset_configuration(struct usb_device *dev)
{
	int			i, retval;
	struct usb_host_config	*config;

	if (dev->state == USB_STATE_SUSPENDED)
		return -EHOSTUNREACH;

	/* caller must have locked the device and must own
	 * the usb bus readlock (so driver bindings are stable);
	 * calls during probe() are fine
	 */

	for (i = 1; i < 16; ++i) {
		usb_disable_endpoint(dev, i);
		usb_disable_endpoint(dev, i + USB_DIR_IN);
	}

	config = dev->actconfig;
	retval = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
			USB_REQ_SET_CONFIGURATION, 0,
			config->desc.bConfigurationValue, 0,
			NULL, 0, USB_CTRL_SET_TIMEOUT);
	if (retval < 0)
		return retval;

	dev->toggle[0] = dev->toggle[1] = 0;

	/* re-init hc/hcd interface/endpoint state */
	for (i = 0; i < config->desc.bNumInterfaces; i++) {
		struct usb_interface *intf = config->interface[i];
		struct usb_host_interface *alt;

		if (device_is_registered(&intf->dev))
			usb_remove_sysfs_intf_files(intf);
		alt = usb_altnum_to_altsetting(intf, 0);

		/* No altsetting 0?  We'll assume the first altsetting.
		 * We could use a GetInterface call, but if a device is
		 * so non-compliant that it doesn't have altsetting 0
		 * then I wouldn't trust its reply anyway.
		 */
		if (!alt)
			alt = &intf->altsetting[0];

		intf->cur_altsetting = alt;
		usb_enable_interface(dev, intf);
		if (device_is_registered(&intf->dev))
			usb_create_sysfs_intf_files(intf);
	}
	return 0;
}

static void usb_release_interface(struct device *dev)
{
	struct usb_interface *intf = to_usb_interface(dev);
	struct usb_interface_cache *intfc =
			altsetting_to_usb_interface_cache(intf->altsetting);

	kref_put(&intfc->ref, usb_release_interface_cache);
	kfree(intf);
}

#ifdef	CONFIG_HOTPLUG
static int usb_if_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	struct usb_device *usb_dev;
	struct usb_interface *intf;
	struct usb_host_interface *alt;

	intf = to_usb_interface(dev);
	usb_dev = interface_to_usbdev(intf);
	alt = intf->cur_altsetting;

	if (add_uevent_var(env, "INTERFACE=%d/%d/%d",
		   alt->desc.bInterfaceClass,
		   alt->desc.bInterfaceSubClass,
		   alt->desc.bInterfaceProtocol))
		return -ENOMEM;

	if (add_uevent_var(env,
		   "MODALIAS=usb:v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02X",
		   le16_to_cpu(usb_dev->descriptor.idVendor),
		   le16_to_cpu(usb_dev->descriptor.idProduct),
		   le16_to_cpu(usb_dev->descriptor.bcdDevice),
		   usb_dev->descriptor.bDeviceClass,
		   usb_dev->descriptor.bDeviceSubClass,
		   usb_dev->descriptor.bDeviceProtocol,
		   alt->desc.bInterfaceClass,
		   alt->desc.bInterfaceSubClass,
		   alt->desc.bInterfaceProtocol))
		return -ENOMEM;

	return 0;
}

#else

static int usb_if_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	return -ENODEV;
}
#endif	/* CONFIG_HOTPLUG */

struct device_type usb_if_device_type = {
	.name =		"usb_interface",
	.release =	usb_release_interface,
	.uevent =	usb_if_uevent,
};

static struct usb_interface_assoc_descriptor *find_iad(struct usb_device *dev,
						       struct usb_host_config *config,
						       u8 inum)
{
	struct usb_interface_assoc_descriptor *retval = NULL;
	struct usb_interface_assoc_descriptor *intf_assoc;
	int first_intf;
	int last_intf;
	int i;

	for (i = 0; (i < USB_MAXIADS && config->intf_assoc[i]); i++) {
		intf_assoc = config->intf_assoc[i];
		if (intf_assoc->bInterfaceCount == 0)
			continue;

		first_intf = intf_assoc->bFirstInterface;
		last_intf = first_intf + (intf_assoc->bInterfaceCount - 1);
		if (inum >= first_intf && inum <= last_intf) {
			if (!retval)
				retval = intf_assoc;
			else
				dev_err(&dev->dev, "Interface #%d referenced"
					" by multiple IADs\n", inum);
		}
	}

	return retval;
}


/*
 * usb_set_configuration - Makes a particular device setting be current
 * @dev: the device whose configuration is being updated
 * @configuration: the configuration being chosen.
 * Context: !in_interrupt(), caller owns the device lock
 *
 * This is used to enable non-default device modes.  Not all devices
 * use this kind of configurability; many devices only have one
 * configuration.
 *
 * @configuration is the value of the configuration to be installed.
 * According to the USB spec (e.g. section 9.1.1.5), configuration values
 * must be non-zero; a value of zero indicates that the device in
 * unconfigured.  However some devices erroneously use 0 as one of their
 * configuration values.  To help manage such devices, this routine will
 * accept @configuration = -1 as indicating the device should be put in
 * an unconfigured state.
 *
 * USB device configurations may affect Linux interoperability,
 * power consumption and the functionality available.  For example,
 * the default configuration is limited to using 100mA of bus power,
 * so that when certain device functionality requires more power,
 * and the device is bus powered, that functionality should be in some
 * non-default device configuration.  Other device modes may also be
 * reflected as configuration options, such as whether two ISDN
 * channels are available independently; and choosing between open
 * standard device protocols (like CDC) or proprietary ones.
 *
 * Note that a non-authorized device (dev->authorized == 0) will only
 * be put in unconfigured mode.
 *
 * Note that USB has an additional level of device configurability,
 * associated with interfaces.  That configurability is accessed using
 * usb_set_interface().
 *
 * This call is synchronous. The calling context must be able to sleep,
 * must own the device lock, and must not hold the driver model's USB
 * bus mutex; usb device driver probe() methods cannot use this routine.
 *
 * Returns zero on success, or else the status code returned by the
 * underlying call that failed.  On successful completion, each interface
 * in the original device configuration has been destroyed, and each one
 * in the new configuration has been probed by all relevant usb device
 * drivers currently known to the kernel.
 */
int usb_set_configuration(struct usb_device *dev, int configuration)
{
	int i, ret;
	struct usb_host_config *cp = NULL;
	struct usb_interface **new_interfaces = NULL;
	int n, nintf;

	if (dev->authorized == 0 || configuration == -1)
		configuration = 0;
	else {
		for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
			if (dev->config[i].desc.bConfigurationValue ==
					configuration) {
				cp = &dev->config[i];
				break;
			}
		}
	}
	if ((!cp && configuration != 0))
		return -EINVAL;

	/* The USB spec says configuration 0 means unconfigured.
	 * But if a device includes a configuration numbered 0,
	 * we will accept it as a correctly configured state.
	 * Use -1 if you really want to unconfigure the device.
	 */
	if (cp && configuration == 0)
		dev_warn(&dev->dev, "config 0 descriptor??\n");

	/* Allocate memory for new interfaces before doing anything else,
	 * so that if we run out then nothing will have changed. */
	n = nintf = 0;
	if (cp) {
		nintf = cp->desc.bNumInterfaces;
		new_interfaces = kmalloc(nintf * sizeof(*new_interfaces),
				GFP_KERNEL);
		if (!new_interfaces) {
			dev_err(&dev->dev, "Out of memory\n");
			return -ENOMEM;
		}

		for (; n < nintf; ++n) {
			new_interfaces[n] = kzalloc(
					sizeof(struct usb_interface),
					GFP_KERNEL);
			if (!new_interfaces[n]) {
				dev_err(&dev->dev, "Out of memory\n");
				ret = -ENOMEM;
free_interfaces:
				while (--n >= 0)
					kfree(new_interfaces[n]);
				kfree(new_interfaces);
				return ret;
			}
		}

		i = dev->bus_mA - cp->desc.bMaxPower * 2;
		if (i < 0)
			dev_warn(&dev->dev, "new config #%d exceeds power "
					"limit by %dmA\n",
					configuration, -i);
	}

	/* Wake up the device so we can send it the Set-Config request */
	ret = usb_autoresume_device(dev);
	if (ret)
		goto free_interfaces;

	/* if it's already configured, clear out old state first.
	 * getting rid of old interfaces means unbinding their drivers.
	 */
	if (dev->state != USB_STATE_ADDRESS)
		usb_disable_device (dev, 1);	// Skip ep0

	if ((ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
			USB_REQ_SET_CONFIGURATION, 0, configuration, 0,
			NULL, 0, USB_CTRL_SET_TIMEOUT)) < 0) {

		/* All the old state is gone, so what else can we do?
		 * The device is probably useless now anyway.
		 */
		cp = NULL;
	}

	dev->actconfig = cp;
	if (!cp) {
		usb_set_device_state(dev, USB_STATE_ADDRESS);
		usb_autosuspend_device(dev);
		goto free_interfaces;
	}
	usb_set_device_state(dev, USB_STATE_CONFIGURED);

	/* Initialize the new interface structures and the
	 * hc/hcd/usbcore interface/endpoint state.
	 */
	for (i = 0; i < nintf; ++i) {
		struct usb_interface_cache *intfc;
		struct usb_interface *intf;
		struct usb_host_interface *alt;

		cp->interface[i] = intf = new_interfaces[i];
		intfc = cp->intf_cache[i];
		intf->altsetting = intfc->altsetting;
		intf->num_altsetting = intfc->num_altsetting;
		intf->intf_assoc = find_iad(dev, cp, i);
		kref_get(&intfc->ref);

		alt = usb_altnum_to_altsetting(intf, 0);

		/* No altsetting 0?  We'll assume the first altsetting.
		 * We could use a GetInterface call, but if a device is
		 * so non-compliant that it doesn't have altsetting 0
		 * then I wouldn't trust its reply anyway.
		 */
		if (!alt)
			alt = &intf->altsetting[0];

		intf->cur_altsetting = alt;
		usb_enable_interface(dev, intf);
		intf->dev.parent = &dev->dev;
		intf->dev.driver = NULL;
		intf->dev.bus = &usb_bus_type;
		intf->dev.type = &usb_if_device_type;
		intf->dev.dma_mask = dev->dev.dma_mask;
		device_initialize (&intf->dev);
		mark_quiesced(intf);
		sprintf (&intf->dev.bus_id[0], "%d-%s:%d.%d",
			 dev->bus->busnum, dev->devpath,
			 configuration, alt->desc.bInterfaceNumber);
	}
	kfree(new_interfaces);

	if (cp->string == NULL)
		cp->string = usb_cache_string(dev, cp->desc.iConfiguration);

	/* Now that all the interfaces are set up, register them
	 * to trigger binding of drivers to interfaces.  probe()
	 * routines may install different altsettings and may
	 * claim() any interfaces not yet bound.  Many class drivers
	 * need that: CDC, audio, video, etc.
	 */
	for (i = 0; i < nintf; ++i) {
		struct usb_interface *intf = cp->interface[i];

		dev_dbg (&dev->dev,
			"adding %s (config #%d, interface %d)\n",
			intf->dev.bus_id, configuration,
			intf->cur_altsetting->desc.bInterfaceNumber);
		ret = device_add (&intf->dev);
		if (ret != 0) {
			dev_err(&dev->dev, "device_add(%s) --> %d\n",
				intf->dev.bus_id, ret);
			continue;
		}
		usb_create_sysfs_intf_files(intf);
	}

	usb_autosuspend_device(dev);
	return 0;
}

struct set_config_request {
	struct usb_device	*udev;
	int			config;
	struct work_struct	work;
};

/* Worker routine for usb_driver_set_configuration() */
static void driver_set_config_work(struct work_struct *work)
{
	struct set_config_request *req =
		container_of(work, struct set_config_request, work);

	usb_lock_device(req->udev);
	usb_set_configuration(req->udev, req->config);
	usb_unlock_device(req->udev);
	usb_put_dev(req->udev);
	kfree(req);
}

/**
 * usb_driver_set_configuration - Provide a way for drivers to change device configurations
 * @udev: the device whose configuration is being updated
 * @config: the configuration being chosen.
 * Context: In process context, must be able to sleep
 *
 * Device interface drivers are not allowed to change device configurations.
 * This is because changing configurations will destroy the interface the
 * driver is bound to and create new ones; it would be like a floppy-disk
 * driver telling the computer to replace the floppy-disk drive with a
 * tape drive!
 *
 * Still, in certain specialized circumstances the need may arise.  This
 * routine gets around the normal restrictions by using a work thread to
 * submit the change-config request.
 *
 * Returns 0 if the request was succesfully queued, error code otherwise.
 * The caller has no way to know whether the queued request will eventually
 * succeed.
 */
int usb_driver_set_configuration(struct usb_device *udev, int config)
{
	struct set_config_request *req;

	req = kmalloc(sizeof(*req), GFP_KERNEL);
	if (!req)
		return -ENOMEM;
	req->udev = udev;
	req->config = config;
	INIT_WORK(&req->work, driver_set_config_work);

	usb_get_dev(udev);
	schedule_work(&req->work);
	return 0;
}
EXPORT_SYMBOL_GPL(usb_driver_set_configuration);

// synchronous request completion model
EXPORT_SYMBOL(usb_control_msg);
EXPORT_SYMBOL(usb_bulk_msg);

EXPORT_SYMBOL(usb_sg_init);
EXPORT_SYMBOL(usb_sg_cancel);
EXPORT_SYMBOL(usb_sg_wait);

// synchronous control message convenience routines
EXPORT_SYMBOL(usb_get_descriptor);
EXPORT_SYMBOL(usb_get_status);
EXPORT_SYMBOL(usb_string);

// synchronous calls that also maintain usbcore state
EXPORT_SYMBOL(usb_clear_halt);
EXPORT_SYMBOL(usb_reset_configuration);
EXPORT_SYMBOL(usb_set_interface);