core.c

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/**
 * device_remove_bin_file - remove sysfs binary attribute file
 * @dev: device.
 * @attr: device binary attribute descriptor.
 */
void device_remove_bin_file(struct device *dev, struct bin_attribute *attr)
{
	if (dev)
		sysfs_remove_bin_file(&dev->kobj, attr);
}
EXPORT_SYMBOL_GPL(device_remove_bin_file);

/**
 * device_schedule_callback_owner - helper to schedule a callback for a device
 * @dev: device.
 * @func: callback function to invoke later.
 * @owner: module owning the callback routine
 *
 * Attribute methods must not unregister themselves or their parent device
 * (which would amount to the same thing).  Attempts to do so will deadlock,
 * since unregistration is mutually exclusive with driver callbacks.
 *
 * Instead methods can call this routine, which will attempt to allocate
 * and schedule a workqueue request to call back @func with @dev as its
 * argument in the workqueue's process context.  @dev will be pinned until
 * @func returns.
 *
 * This routine is usually called via the inline device_schedule_callback(),
 * which automatically sets @owner to THIS_MODULE.
 *
 * Returns 0 if the request was submitted, -ENOMEM if storage could not
 * be allocated, -ENODEV if a reference to @owner isn't available.
 *
 * NOTE: This routine won't work if CONFIG_SYSFS isn't set!  It uses an
 * underlying sysfs routine (since it is intended for use by attribute
 * methods), and if sysfs isn't available you'll get nothing but -ENOSYS.
 */
int device_schedule_callback_owner(struct device *dev,
		void (*func)(struct device *), struct module *owner)
{
	return sysfs_schedule_callback(&dev->kobj,
			(void (*)(void *)) func, dev, owner);
}
EXPORT_SYMBOL_GPL(device_schedule_callback_owner);

static void klist_children_get(struct klist_node *n)
{
	struct device *dev = container_of(n, struct device, knode_parent);

	get_device(dev);
}

static void klist_children_put(struct klist_node *n)
{
	struct device *dev = container_of(n, struct device, knode_parent);

	put_device(dev);
}


/**
 *	device_initialize - init device structure.
 *	@dev:	device.
 *
 *	This prepares the device for use by other layers,
 *	including adding it to the device hierarchy.
 *	It is the first half of device_register(), if called by
 *	that, though it can also be called separately, so one
 *	may use @dev's fields (e.g. the refcount).
 */

void device_initialize(struct device *dev)
{
	kobj_set_kset_s(dev, devices_subsys);
	kobject_init(&dev->kobj);
	klist_init(&dev->klist_children, klist_children_get,
		   klist_children_put);
	INIT_LIST_HEAD(&dev->dma_pools);
	INIT_LIST_HEAD(&dev->node);
	init_MUTEX(&dev->sem);
	spin_lock_init(&dev->devres_lock);
	INIT_LIST_HEAD(&dev->devres_head);
	device_init_wakeup(dev, 0);
	set_dev_node(dev, -1);
}

#ifdef CONFIG_SYSFS_DEPRECATED
static struct kobject * get_device_parent(struct device *dev,
					  struct device *parent)
{
	/*
	 * Set the parent to the class, not the parent device
	 * for topmost devices in class hierarchy.
	 * This keeps sysfs from having a symlink to make old
	 * udevs happy
	 */
	if (dev->class && (!parent || parent->class != dev->class))
		return &dev->class->subsys.kobj;
	else if (parent)
		return &parent->kobj;

	return NULL;
}
#else
static struct kobject *virtual_device_parent(struct device *dev)
{
	static struct kobject *virtual_dir = NULL;

	if (!virtual_dir)
		virtual_dir = kobject_add_dir(&devices_subsys.kobj, "virtual");

	return virtual_dir;
}

static struct kobject * get_device_parent(struct device *dev,
					  struct device *parent)
{
	if (dev->class) {
		struct kobject *kobj = NULL;
		struct kobject *parent_kobj;
		struct kobject *k;

		/*
		 * If we have no parent, we live in "virtual".
		 * Class-devices with a bus-device as parent, live
		 * in a class-directory to prevent namespace collisions.
		 */
		if (parent == NULL)
			parent_kobj = virtual_device_parent(dev);
		else if (parent->class)
			return &parent->kobj;
		else
			parent_kobj = &parent->kobj;

		/* find our class-directory at the parent and reference it */
		spin_lock(&dev->class->class_dirs.list_lock);
		list_for_each_entry(k, &dev->class->class_dirs.list, entry)
			if (k->parent == parent_kobj) {
				kobj = kobject_get(k);
				break;
			}
		spin_unlock(&dev->class->class_dirs.list_lock);
		if (kobj)
			return kobj;

		/* or create a new class-directory at the parent device */
		return kobject_kset_add_dir(&dev->class->class_dirs,
					    parent_kobj, dev->class->name);
	}

	if (parent)
		return &parent->kobj;
	return NULL;
}
#endif

static int setup_parent(struct device *dev, struct device *parent)
{
	struct kobject *kobj;
	kobj = get_device_parent(dev, parent);
	if (IS_ERR(kobj))
		return PTR_ERR(kobj);
	if (kobj)
		dev->kobj.parent = kobj;
	return 0;
}

static int device_add_class_symlinks(struct device *dev)
{
	int error;

	if (!dev->class)
		return 0;
	error = sysfs_create_link(&dev->kobj, &dev->class->subsys.kobj,
				  "subsystem");
	if (error)
		goto out;
	/*
	 * If this is not a "fake" compatible device, then create the
	 * symlink from the class to the device.
	 */
	if (dev->kobj.parent != &dev->class->subsys.kobj) {
		error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
					  dev->bus_id);
		if (error)
			goto out_subsys;
	}
	if (dev->parent) {
#ifdef CONFIG_SYSFS_DEPRECATED
		{
			struct device *parent = dev->parent;
			char *class_name;

			/*
			 * In old sysfs stacked class devices had 'device'
			 * link pointing to real device instead of parent
			 */
			while (parent->class && !parent->bus && parent->parent)
				parent = parent->parent;

			error = sysfs_create_link(&dev->kobj,
						  &parent->kobj,
						  "device");
			if (error)
				goto out_busid;

			class_name = make_class_name(dev->class->name,
							&dev->kobj);
			if (class_name)
				error = sysfs_create_link(&dev->parent->kobj,
							&dev->kobj, class_name);
			kfree(class_name);
			if (error)
				goto out_device;
		}
#else
		error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
					  "device");
		if (error)
			goto out_busid;
#endif
	}
	return 0;

#ifdef CONFIG_SYSFS_DEPRECATED
out_device:
	if (dev->parent)
		sysfs_remove_link(&dev->kobj, "device");
#endif
out_busid:
	if (dev->kobj.parent != &dev->class->subsys.kobj)
		sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
out_subsys:
	sysfs_remove_link(&dev->kobj, "subsystem");
out:
	return error;
}

static void device_remove_class_symlinks(struct device *dev)
{
	if (!dev->class)
		return;
	if (dev->parent) {
#ifdef CONFIG_SYSFS_DEPRECATED
		char *class_name;

		class_name = make_class_name(dev->class->name, &dev->kobj);
		if (class_name) {
			sysfs_remove_link(&dev->parent->kobj, class_name);
			kfree(class_name);
		}
#endif
		sysfs_remove_link(&dev->kobj, "device");
	}
	if (dev->kobj.parent != &dev->class->subsys.kobj)
		sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
	sysfs_remove_link(&dev->kobj, "subsystem");
}

/**
 *	device_add - add device to device hierarchy.
 *	@dev:	device.
 *
 *	This is part 2 of device_register(), though may be called
 *	separately _iff_ device_initialize() has been called separately.
 *
 *	This adds it to the kobject hierarchy via kobject_add(), adds it
 *	to the global and sibling lists for the device, then
 *	adds it to the other relevant subsystems of the driver model.
 */
int device_add(struct device *dev)
{
	struct device *parent = NULL;
	struct class_interface *class_intf;
	int error = -EINVAL;

	dev = get_device(dev);
	if (!dev || !strlen(dev->bus_id))
		goto Error;

	pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);

	parent = get_device(dev->parent);
	error = setup_parent(dev, parent);
	if (error)
		goto Error;

	/* first, register with generic layer. */
	kobject_set_name(&dev->kobj, "%s", dev->bus_id);
	error = kobject_add(&dev->kobj);
	if (error)
		goto Error;

	/* notify platform of device entry */
	if (platform_notify)
		platform_notify(dev);

	/* notify clients of device entry (new way) */
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->bus_notifier,
					     BUS_NOTIFY_ADD_DEVICE, dev);

	error = device_create_file(dev, &uevent_attr);
	if (error)
		goto attrError;

	if (MAJOR(dev->devt)) {
		error = device_create_file(dev, &devt_attr);
		if (error)
			goto ueventattrError;
	}

	error = device_add_class_symlinks(dev);
	if (error)
		goto SymlinkError;
	error = device_add_attrs(dev);
	if (error)
		goto AttrsError;
	error = dpm_sysfs_add(dev);
	if (error)
		goto PMError;
	device_pm_add(dev);
	error = bus_add_device(dev);
	if (error)
		goto BusError;
	kobject_uevent(&dev->kobj, KOBJ_ADD);
	bus_attach_device(dev);
	if (parent)
		klist_add_tail(&dev->knode_parent, &parent->klist_children);

	if (dev->class) {
		down(&dev->class->sem);
		/* tie the class to the device */
		list_add_tail(&dev->node, &dev->class->devices);

		/* notify any interfaces that the device is here */
		list_for_each_entry(class_intf, &dev->class->interfaces, node)
			if (class_intf->add_dev)
				class_intf->add_dev(dev, class_intf);
		up(&dev->class->sem);
	}
 Done:
	put_device(dev);
	return error;
 BusError:
	device_pm_remove(dev);
	dpm_sysfs_remove(dev);
 PMError:
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->bus_notifier,
					     BUS_NOTIFY_DEL_DEVICE, dev);
	device_remove_attrs(dev);
 AttrsError:
	device_remove_class_symlinks(dev);
 SymlinkError:
	if (MAJOR(dev->devt))
		device_remove_file(dev, &devt_attr);

	if (dev->class) {
		sysfs_remove_link(&dev->kobj, "subsystem");
		/* If this is not a "fake" compatible device, remove the
		 * symlink from the class to the device. */
		if (dev->kobj.parent != &dev->class->subsys.kobj)
			sysfs_remove_link(&dev->class->subsys.kobj,
					  dev->bus_id);
		if (parent) {
#ifdef CONFIG_SYSFS_DEPRECATED
			char *class_name = make_class_name(dev->class->name,
							   &dev->kobj);
			if (class_name)
				sysfs_remove_link(&dev->parent->kobj,
						  class_name);
			kfree(class_name);
#endif
			sysfs_remove_link(&dev->kobj, "device");
		}
	}
 ueventattrError:
	device_remove_file(dev, &uevent_attr);
 attrError:
	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
	kobject_del(&dev->kobj);
 Error:
	if (parent)
		put_device(parent);
	goto Done;
}


/**
 *	device_register - register a device with the system.
 *	@dev:	pointer to the device structure
 *
 *	This happens in two clean steps - initialize the device
 *	and add it to the system. The two steps can be called
 *	separately, but this is the easiest and most common.
 *	I.e. you should only call the two helpers separately if
 *	have a clearly defined need to use and refcount the device
 *	before it is added to the hierarchy.
 */

int device_register(struct device *dev)
{
	device_initialize(dev);
	return device_add(dev);
}


/**
 *	get_device - increment reference count for device.
 *	@dev:	device.
 *
 *	This simply forwards the call to kobject_get(), though
 *	we do take care to provide for the case that we get a NULL
 *	pointer passed in.
 */

struct device * get_device(struct device * dev)
{
	return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
}


/**
 *	put_device - decrement reference count.
 *	@dev:	device in question.
 */
void put_device(struct device * dev)
{
	if (dev)
		kobject_put(&dev->kobj);
}


/**
 *	device_del - delete device from system.
 *	@dev:	device.
 *
 *	This is the first part of the device unregistration
 *	sequence. This removes the device from the lists we control
 *	from here, has it removed from the other driver model
 *	subsystems it was added to in device_add(), and removes it
 *	from the kobject hierarchy.
 *
 *	NOTE: this should be called manually _iff_ device_add() was
 *	also called manually.
 */

void device_del(struct device * dev)
{
	struct device * parent = dev->parent;
	struct class_interface *class_intf;