class.c

来自「linux 内核源代码」· C语言 代码 · 共 893 行 · 第 1/2 页

static struct kset_uevent_ops class_uevent_ops = {
	.filter =	class_uevent_filter,
	.name =		class_uevent_name,
	.uevent =	class_uevent,
};

static decl_subsys(class_obj, &class_device_ktype, &class_uevent_ops);


static int class_device_add_attrs(struct class_device * cd)
{
	int i;
	int error = 0;
	struct class * cls = cd->class;

	if (cls->class_dev_attrs) {
		for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
			error = class_device_create_file(cd,
							 &cls->class_dev_attrs[i]);
			if (error)
				goto Err;
		}
	}
 Done:
	return error;
 Err:
	while (--i >= 0)
		class_device_remove_file(cd,&cls->class_dev_attrs[i]);
	goto Done;
}

static void class_device_remove_attrs(struct class_device * cd)
{
	int i;
	struct class * cls = cd->class;

	if (cls->class_dev_attrs) {
		for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
			class_device_remove_file(cd,&cls->class_dev_attrs[i]);
	}
}

static int class_device_add_groups(struct class_device * cd)
{
	int i;
	int error = 0;

	if (cd->groups) {
		for (i = 0; cd->groups[i]; i++) {
			error = sysfs_create_group(&cd->kobj, cd->groups[i]);
			if (error) {
				while (--i >= 0)
					sysfs_remove_group(&cd->kobj, cd->groups[i]);
				goto out;
			}
		}
	}
out:
	return error;
}

static void class_device_remove_groups(struct class_device * cd)
{
	int i;
	if (cd->groups) {
		for (i = 0; cd->groups[i]; i++) {
			sysfs_remove_group(&cd->kobj, cd->groups[i]);
		}
	}
}

static ssize_t show_dev(struct class_device *class_dev, char *buf)
{
	return print_dev_t(buf, class_dev->devt);
}

static struct class_device_attribute class_devt_attr =
	__ATTR(dev, S_IRUGO, show_dev, NULL);

static ssize_t store_uevent(struct class_device *class_dev,
			    const char *buf, size_t count)
{
	kobject_uevent(&class_dev->kobj, KOBJ_ADD);
	return count;
}

static struct class_device_attribute class_uevent_attr =
	__ATTR(uevent, S_IWUSR, NULL, store_uevent);

void class_device_initialize(struct class_device *class_dev)
{
	kobj_set_kset_s(class_dev, class_obj_subsys);
	kobject_init(&class_dev->kobj);
	INIT_LIST_HEAD(&class_dev->node);
}

int class_device_add(struct class_device *class_dev)
{
	struct class *parent_class = NULL;
	struct class_device *parent_class_dev = NULL;
	struct class_interface *class_intf;
	int error = -EINVAL;

	class_dev = class_device_get(class_dev);
	if (!class_dev)
		return -EINVAL;

	if (!strlen(class_dev->class_id))
		goto out1;

	parent_class = class_get(class_dev->class);
	if (!parent_class)
		goto out1;

	parent_class_dev = class_device_get(class_dev->parent);

	pr_debug("CLASS: registering class device: ID = '%s'\n",
		 class_dev->class_id);

	/* first, register with generic layer. */
	error = kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
	if (error)
		goto out2;

	if (parent_class_dev)
		class_dev->kobj.parent = &parent_class_dev->kobj;
	else
		class_dev->kobj.parent = &parent_class->subsys.kobj;

	error = kobject_add(&class_dev->kobj);
	if (error)
		goto out2;

	/* add the needed attributes to this device */
	error = sysfs_create_link(&class_dev->kobj,
				  &parent_class->subsys.kobj, "subsystem");
	if (error)
		goto out3;

	error = class_device_create_file(class_dev, &class_uevent_attr);
	if (error)
		goto out3;

	if (MAJOR(class_dev->devt)) {
		error = class_device_create_file(class_dev, &class_devt_attr);
		if (error)
			goto out4;
	}

	error = class_device_add_attrs(class_dev);
	if (error)
		goto out5;

	if (class_dev->dev) {
		error = sysfs_create_link(&class_dev->kobj,
					  &class_dev->dev->kobj, "device");
		if (error)
			goto out6;
	}

	error = class_device_add_groups(class_dev);
	if (error)
		goto out7;

	error = make_deprecated_class_device_links(class_dev);
	if (error)
		goto out8;

	kobject_uevent(&class_dev->kobj, KOBJ_ADD);

	/* notify any interfaces this device is now here */
	down(&parent_class->sem);
	list_add_tail(&class_dev->node, &parent_class->children);
	list_for_each_entry(class_intf, &parent_class->interfaces, node) {
		if (class_intf->add)
			class_intf->add(class_dev, class_intf);
	}
	up(&parent_class->sem);

	goto out1;

 out8:
	class_device_remove_groups(class_dev);
 out7:
	if (class_dev->dev)
		sysfs_remove_link(&class_dev->kobj, "device");
 out6:
	class_device_remove_attrs(class_dev);
 out5:
	if (MAJOR(class_dev->devt))
		class_device_remove_file(class_dev, &class_devt_attr);
 out4:
	class_device_remove_file(class_dev, &class_uevent_attr);
 out3:
	kobject_del(&class_dev->kobj);
 out2:
	if(parent_class_dev)
		class_device_put(parent_class_dev);
	class_put(parent_class);
 out1:
	class_device_put(class_dev);
	return error;
}

int class_device_register(struct class_device *class_dev)
{
	class_device_initialize(class_dev);
	return class_device_add(class_dev);
}

/**
 * class_device_create - creates a class device and registers it with sysfs
 * @cls: pointer to the struct class that this device should be registered to.
 * @parent: pointer to the parent struct class_device of this new device, if any.
 * @devt: the dev_t for the char device to be added.
 * @device: a pointer to a struct device that is assiociated with this class device.
 * @fmt: string for the class device's name
 *
 * This function can be used by char device classes.  A struct
 * class_device will be created in sysfs, registered to the specified
 * class.
 * A "dev" file will be created, showing the dev_t for the device, if
 * the dev_t is not 0,0.
 * If a pointer to a parent struct class_device is passed in, the newly
 * created struct class_device will be a child of that device in sysfs.
 * The pointer to the struct class_device will be returned from the
 * call.  Any further sysfs files that might be required can be created
 * using this pointer.
 *
 * Note: the struct class passed to this function must have previously
 * been created with a call to class_create().
 */
struct class_device *class_device_create(struct class *cls,
					 struct class_device *parent,
					 dev_t devt,
					 struct device *device,
					 const char *fmt, ...)
{
	va_list args;
	struct class_device *class_dev = NULL;
	int retval = -ENODEV;

	if (cls == NULL || IS_ERR(cls))
		goto error;

	class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
	if (!class_dev) {
		retval = -ENOMEM;
		goto error;
	}

	class_dev->devt = devt;
	class_dev->dev = device;
	class_dev->class = cls;
	class_dev->parent = parent;
	class_dev->release = class_device_create_release;
	class_dev->uevent = class_device_create_uevent;

	va_start(args, fmt);
	vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
	va_end(args);
	retval = class_device_register(class_dev);
	if (retval)
		goto error;

	return class_dev;

error:
	kfree(class_dev);
	return ERR_PTR(retval);
}

void class_device_del(struct class_device *class_dev)
{
	struct class *parent_class = class_dev->class;
	struct class_device *parent_device = class_dev->parent;
	struct class_interface *class_intf;

	if (parent_class) {
		down(&parent_class->sem);
		list_del_init(&class_dev->node);
		list_for_each_entry(class_intf, &parent_class->interfaces, node)
			if (class_intf->remove)
				class_intf->remove(class_dev, class_intf);
		up(&parent_class->sem);
	}

	if (class_dev->dev) {
		remove_deprecated_class_device_links(class_dev);
		sysfs_remove_link(&class_dev->kobj, "device");
	}
	sysfs_remove_link(&class_dev->kobj, "subsystem");
	class_device_remove_file(class_dev, &class_uevent_attr);
	if (MAJOR(class_dev->devt))
		class_device_remove_file(class_dev, &class_devt_attr);
	class_device_remove_attrs(class_dev);
	class_device_remove_groups(class_dev);

	kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
	kobject_del(&class_dev->kobj);

	class_device_put(parent_device);
	class_put(parent_class);
}

void class_device_unregister(struct class_device *class_dev)
{
	pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
		 class_dev->class_id);
	class_device_del(class_dev);
	class_device_put(class_dev);
}

/**
 * class_device_destroy - removes a class device that was created with class_device_create()
 * @cls: the pointer to the struct class that this device was registered * with.
 * @devt: the dev_t of the device that was previously registered.
 *
 * This call unregisters and cleans up a class device that was created with a
 * call to class_device_create()
 */
void class_device_destroy(struct class *cls, dev_t devt)
{
	struct class_device *class_dev = NULL;
	struct class_device *class_dev_tmp;

	down(&cls->sem);
	list_for_each_entry(class_dev_tmp, &cls->children, node) {
		if (class_dev_tmp->devt == devt) {
			class_dev = class_dev_tmp;
			break;
		}
	}
	up(&cls->sem);

	if (class_dev)
		class_device_unregister(class_dev);
}

struct class_device * class_device_get(struct class_device *class_dev)
{
	if (class_dev)
		return to_class_dev(kobject_get(&class_dev->kobj));
	return NULL;
}

void class_device_put(struct class_device *class_dev)
{
	if (class_dev)
		kobject_put(&class_dev->kobj);
}


int class_interface_register(struct class_interface *class_intf)
{
	struct class *parent;
	struct class_device *class_dev;
	struct device *dev;

	if (!class_intf || !class_intf->class)
		return -ENODEV;

	parent = class_get(class_intf->class);
	if (!parent)
		return -EINVAL;

	down(&parent->sem);
	list_add_tail(&class_intf->node, &parent->interfaces);
	if (class_intf->add) {
		list_for_each_entry(class_dev, &parent->children, node)
			class_intf->add(class_dev, class_intf);
	}
	if (class_intf->add_dev) {
		list_for_each_entry(dev, &parent->devices, node)
			class_intf->add_dev(dev, class_intf);
	}
	up(&parent->sem);

	return 0;
}

void class_interface_unregister(struct class_interface *class_intf)
{
	struct class * parent = class_intf->class;
	struct class_device *class_dev;
	struct device *dev;

	if (!parent)
		return;

	down(&parent->sem);
	list_del_init(&class_intf->node);
	if (class_intf->remove) {
		list_for_each_entry(class_dev, &parent->children, node)
			class_intf->remove(class_dev, class_intf);
	}
	if (class_intf->remove_dev) {
		list_for_each_entry(dev, &parent->devices, node)
			class_intf->remove_dev(dev, class_intf);
	}
	up(&parent->sem);

	class_put(parent);
}

int __init classes_init(void)
{
	int retval;

	retval = subsystem_register(&class_subsys);
	if (retval)
		return retval;

	/* ick, this is ugly, the things we go through to keep from showing up
	 * in sysfs... */
	kset_init(&class_obj_subsys);
	if (!class_obj_subsys.kobj.parent)
		class_obj_subsys.kobj.parent = &class_obj_subsys.kobj;
	return 0;
}

EXPORT_SYMBOL_GPL(class_create_file);
EXPORT_SYMBOL_GPL(class_remove_file);
EXPORT_SYMBOL_GPL(class_register);
EXPORT_SYMBOL_GPL(class_unregister);
EXPORT_SYMBOL_GPL(class_create);
EXPORT_SYMBOL_GPL(class_destroy);

EXPORT_SYMBOL_GPL(class_device_register);
EXPORT_SYMBOL_GPL(class_device_unregister);
EXPORT_SYMBOL_GPL(class_device_initialize);
EXPORT_SYMBOL_GPL(class_device_add);
EXPORT_SYMBOL_GPL(class_device_del);
EXPORT_SYMBOL_GPL(class_device_get);
EXPORT_SYMBOL_GPL(class_device_put);
EXPORT_SYMBOL_GPL(class_device_create);
EXPORT_SYMBOL_GPL(class_device_destroy);
EXPORT_SYMBOL_GPL(class_device_create_file);
EXPORT_SYMBOL_GPL(class_device_remove_file);
EXPORT_SYMBOL_GPL(class_device_create_bin_file);
EXPORT_SYMBOL_GPL(class_device_remove_bin_file);

EXPORT_SYMBOL_GPL(class_interface_register);
EXPORT_SYMBOL_GPL(class_interface_unregister);