core.c 33.6 KB
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/*
 * drivers/base/core.c - core driver model code (device registration, etc)
 *
 * Copyright (c) 2002-3 Patrick Mochel
 * Copyright (c) 2002-3 Open Source Development Labs
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 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
 * Copyright (c) 2006 Novell, Inc.
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 *
 * This file is released under the GPLv2
 *
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
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#include <linux/kdev_t.h>
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#include <linux/notifier.h>
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#include <linux/genhd.h>
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#include <linux/kallsyms.h>
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#include <linux/semaphore.h>
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#include "base.h"
#include "power/power.h"

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int (*platform_notify)(struct device *dev) = NULL;
int (*platform_notify_remove)(struct device *dev) = NULL;
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#ifdef CONFIG_BLOCK
static inline int device_is_not_partition(struct device *dev)
{
	return !(dev->type == &part_type);
}
#else
static inline int device_is_not_partition(struct device *dev)
{
	return 1;
}
#endif
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/**
 * dev_driver_string - Return a device's driver name, if at all possible
 * @dev: struct device to get the name of
 *
 * Will return the device's driver's name if it is bound to a device.  If
 * the device is not bound to a device, it will return the name of the bus
 * it is attached to.  If it is not attached to a bus either, an empty
 * string will be returned.
 */
const char *dev_driver_string(struct device *dev)
{
	return dev->driver ? dev->driver->name :
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			(dev->bus ? dev->bus->name :
			(dev->class ? dev->class->name : ""));
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}
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EXPORT_SYMBOL(dev_driver_string);
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#define to_dev(obj) container_of(obj, struct device, kobj)
#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)

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static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
			     char *buf)
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{
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	struct device_attribute *dev_attr = to_dev_attr(attr);
	struct device *dev = to_dev(kobj);
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	ssize_t ret = -EIO;
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	if (dev_attr->show)
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		ret = dev_attr->show(dev, dev_attr, buf);
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	if (ret >= (ssize_t)PAGE_SIZE) {
		print_symbol("dev_attr_show: %s returned bad count\n",
				(unsigned long)dev_attr->show);
	}
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	return ret;
}

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static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
			      const char *buf, size_t count)
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{
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	struct device_attribute *dev_attr = to_dev_attr(attr);
	struct device *dev = to_dev(kobj);
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	ssize_t ret = -EIO;
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	if (dev_attr->store)
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		ret = dev_attr->store(dev, dev_attr, buf, count);
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	return ret;
}

static struct sysfs_ops dev_sysfs_ops = {
	.show	= dev_attr_show,
	.store	= dev_attr_store,
};


/**
 *	device_release - free device structure.
 *	@kobj:	device's kobject.
 *
 *	This is called once the reference count for the object
 *	reaches 0. We forward the call to the device's release
 *	method, which should handle actually freeing the structure.
 */
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static void device_release(struct kobject *kobj)
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{
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	struct device *dev = to_dev(kobj);
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	if (dev->release)
		dev->release(dev);
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	else if (dev->type && dev->type->release)
		dev->type->release(dev);
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	else if (dev->class && dev->class->dev_release)
		dev->class->dev_release(dev);
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	else {
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		printk(KERN_ERR "Device '%s' does not have a release() "
			"function, it is broken and must be fixed.\n",
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			dev->bus_id);
		WARN_ON(1);
	}
}

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static struct kobj_type device_ktype = {
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	.release	= device_release,
	.sysfs_ops	= &dev_sysfs_ops,
};


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static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
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{
	struct kobj_type *ktype = get_ktype(kobj);

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	if (ktype == &device_ktype) {
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		struct device *dev = to_dev(kobj);
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		if (dev->uevent_suppress)
			return 0;
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		if (dev->bus)
			return 1;
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		if (dev->class)
			return 1;
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	}
	return 0;
}

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static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
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{
	struct device *dev = to_dev(kobj);

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	if (dev->bus)
		return dev->bus->name;
	if (dev->class)
		return dev->class->name;
	return NULL;
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}

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static int dev_uevent(struct kset *kset, struct kobject *kobj,
		      struct kobj_uevent_env *env)
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{
	struct device *dev = to_dev(kobj);
	int retval = 0;

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	/* add the major/minor if present */
	if (MAJOR(dev->devt)) {
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		add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
		add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
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	}

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	if (dev->type && dev->type->name)
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		add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
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	if (dev->driver)
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		add_uevent_var(env, "DRIVER=%s", dev->driver->name);
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#ifdef CONFIG_SYSFS_DEPRECATED
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	if (dev->class) {
		struct device *parent = dev->parent;

		/* find first bus device in parent chain */
		while (parent && !parent->bus)
			parent = parent->parent;
		if (parent && parent->bus) {
			const char *path;

			path = kobject_get_path(&parent->kobj, GFP_KERNEL);
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			if (path) {
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				add_uevent_var(env, "PHYSDEVPATH=%s", path);
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				kfree(path);
			}
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			add_uevent_var(env, "PHYSDEVBUS=%s", parent->bus->name);
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			if (parent->driver)
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				add_uevent_var(env, "PHYSDEVDRIVER=%s",
					       parent->driver->name);
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		}
	} else if (dev->bus) {
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		add_uevent_var(env, "PHYSDEVBUS=%s", dev->bus->name);
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		if (dev->driver)
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			add_uevent_var(env, "PHYSDEVDRIVER=%s",
				       dev->driver->name);
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	}
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#endif
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	/* have the bus specific function add its stuff */
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	if (dev->bus && dev->bus->uevent) {
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		retval = dev->bus->uevent(dev, env);
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		if (retval)
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			pr_debug("device: '%s': %s: bus uevent() returned %d\n",
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				 dev->bus_id, __func__, retval);
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	}

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	/* have the class specific function add its stuff */
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	if (dev->class && dev->class->dev_uevent) {
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		retval = dev->class->dev_uevent(dev, env);
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		if (retval)
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			pr_debug("device: '%s': %s: class uevent() "
				 "returned %d\n", dev->bus_id,
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				 __func__, retval);
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	}

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	/* have the device type specific fuction add its stuff */
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	if (dev->type && dev->type->uevent) {
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		retval = dev->type->uevent(dev, env);
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		if (retval)
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			pr_debug("device: '%s': %s: dev_type uevent() "
				 "returned %d\n", dev->bus_id,
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				 __func__, retval);
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	}

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	return retval;
}

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static struct kset_uevent_ops device_uevent_ops = {
	.filter =	dev_uevent_filter,
	.name =		dev_uevent_name,
	.uevent =	dev_uevent,
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};

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static ssize_t show_uevent(struct device *dev, struct device_attribute *attr,
			   char *buf)
{
	struct kobject *top_kobj;
	struct kset *kset;
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	struct kobj_uevent_env *env = NULL;
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	int i;
	size_t count = 0;
	int retval;

	/* search the kset, the device belongs to */
	top_kobj = &dev->kobj;
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	while (!top_kobj->kset && top_kobj->parent)
		top_kobj = top_kobj->parent;
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	if (!top_kobj->kset)
		goto out;
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	kset = top_kobj->kset;
	if (!kset->uevent_ops || !kset->uevent_ops->uevent)
		goto out;

	/* respect filter */
	if (kset->uevent_ops && kset->uevent_ops->filter)
		if (!kset->uevent_ops->filter(kset, &dev->kobj))
			goto out;

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	env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
	if (!env)
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		return -ENOMEM;

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	/* let the kset specific function add its keys */
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	retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
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	if (retval)
		goto out;

	/* copy keys to file */
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	for (i = 0; i < env->envp_idx; i++)
		count += sprintf(&buf[count], "%s\n", env->envp[i]);
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out:
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	kfree(env);
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	return count;
}

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static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
			    const char *buf, size_t count)
{
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	enum kobject_action action;

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	if (kobject_action_type(buf, count, &action) == 0) {
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		kobject_uevent(&dev->kobj, action);
		goto out;
	}

	dev_err(dev, "uevent: unsupported action-string; this will "
		     "be ignored in a future kernel version\n");
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	kobject_uevent(&dev->kobj, KOBJ_ADD);
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out:
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	return count;
}

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static struct device_attribute uevent_attr =
	__ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent);

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static int device_add_attributes(struct device *dev,
				 struct device_attribute *attrs)
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{
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	int error = 0;
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	int i;
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	if (attrs) {
		for (i = 0; attr_name(attrs[i]); i++) {
			error = device_create_file(dev, &attrs[i]);
			if (error)
				break;
		}
		if (error)
			while (--i >= 0)
				device_remove_file(dev, &attrs[i]);
	}
	return error;
}

static void device_remove_attributes(struct device *dev,
				     struct device_attribute *attrs)
{
	int i;

	if (attrs)
		for (i = 0; attr_name(attrs[i]); i++)
			device_remove_file(dev, &attrs[i]);
}

static int device_add_groups(struct device *dev,
			     struct attribute_group **groups)
{
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	int error = 0;
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	int i;
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	if (groups) {
		for (i = 0; groups[i]; i++) {
			error = sysfs_create_group(&dev->kobj, groups[i]);
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			if (error) {
				while (--i >= 0)
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					sysfs_remove_group(&dev->kobj,
							   groups[i]);
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				break;
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			}
		}
	}
	return error;
}

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static void device_remove_groups(struct device *dev,
				 struct attribute_group **groups)
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{
	int i;
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	if (groups)
		for (i = 0; groups[i]; i++)
			sysfs_remove_group(&dev->kobj, groups[i]);
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}

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static int device_add_attrs(struct device *dev)
{
	struct class *class = dev->class;
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	struct device_type *type = dev->type;
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	int error;
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	if (class) {
		error = device_add_attributes(dev, class->dev_attrs);
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		if (error)
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			return error;
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	}
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	if (type) {
		error = device_add_groups(dev, type->groups);
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		if (error)
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			goto err_remove_class_attrs;
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	}

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	error = device_add_groups(dev, dev->groups);
	if (error)
		goto err_remove_type_groups;

	return 0;

 err_remove_type_groups:
	if (type)
		device_remove_groups(dev, type->groups);
 err_remove_class_attrs:
	if (class)
		device_remove_attributes(dev, class->dev_attrs);

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	return error;
}

static void device_remove_attrs(struct device *dev)
{
	struct class *class = dev->class;
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	struct device_type *type = dev->type;
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	device_remove_groups(dev, dev->groups);
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	if (type)
		device_remove_groups(dev, type->groups);

	if (class)
		device_remove_attributes(dev, class->dev_attrs);
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}


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static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
			char *buf)
{
	return print_dev_t(buf, dev->devt);
}

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static struct device_attribute devt_attr =
	__ATTR(dev, S_IRUGO, show_dev, NULL);

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/* kset to create /sys/devices/  */
struct kset *devices_kset;
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/**
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 * device_create_file - create sysfs attribute file for device.
 * @dev: device.
 * @attr: device attribute descriptor.
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 */
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int device_create_file(struct device *dev, struct device_attribute *attr)
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{
	int error = 0;
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	if (dev)
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		error = sysfs_create_file(&dev->kobj, &attr->attr);
	return error;
}

/**
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 * device_remove_file - remove sysfs attribute file.
 * @dev: device.
 * @attr: device attribute descriptor.
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 */
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void device_remove_file(struct device *dev, struct device_attribute *attr)
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{
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	if (dev)
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		sysfs_remove_file(&dev->kobj, &attr->attr);
}

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/**
 * device_create_bin_file - create sysfs binary attribute file for device.
 * @dev: device.
 * @attr: device binary attribute descriptor.
 */
int device_create_bin_file(struct device *dev, struct bin_attribute *attr)
{
	int error = -EINVAL;
	if (dev)
		error = sysfs_create_bin_file(&dev->kobj, attr);
	return error;
}
EXPORT_SYMBOL_GPL(device_create_bin_file);

/**
 * 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);

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/**
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 * device_schedule_callback_owner - helper to schedule a callback for a device
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 * @dev: device.
 * @func: callback function to invoke later.
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 * @owner: module owning the callback routine
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 *
 * 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.
 *
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 * This routine is usually called via the inline device_schedule_callback(),
 * which automatically sets @owner to THIS_MODULE.
 *
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 * Returns 0 if the request was submitted, -ENOMEM if storage could not
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 * be allocated, -ENODEV if a reference to @owner isn't available.
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 *
 * 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.
 */
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int device_schedule_callback_owner(struct device *dev,
		void (*func)(struct device *), struct module *owner)
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{
	return sysfs_schedule_callback(&dev->kobj,
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			(void (*)(void *)) func, dev, owner);
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}
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EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
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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);
}

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/**
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 * device_initialize - init device structure.
 * @dev: device.
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 *
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 * 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).
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 */
void device_initialize(struct device *dev)
{
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	dev->kobj.kset = devices_kset;
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	kobject_init(&dev->kobj, &device_ktype);
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	klist_init(&dev->klist_children, klist_children_get,
		   klist_children_put);
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	INIT_LIST_HEAD(&dev->dma_pools);
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	INIT_LIST_HEAD(&dev->node);
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	init_MUTEX(&dev->sem);
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	spin_lock_init(&dev->devres_lock);
	INIT_LIST_HEAD(&dev->devres_head);
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	device_init_wakeup(dev, 0);
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	set_dev_node(dev, -1);
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}

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#ifdef CONFIG_SYSFS_DEPRECATED
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static struct kobject *get_device_parent(struct device *dev,
					 struct device *parent)
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{
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	/* class devices without a parent live in /sys/class/<classname>/ */
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	if (dev->class && (!parent || parent->class != dev->class))
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		return &dev->class->subsys.kobj;
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	/* all other devices keep their parent */
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	else if (parent)
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		return &parent->kobj;
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	return NULL;
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}
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static inline void cleanup_device_parent(struct device *dev) {}
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static inline void cleanup_glue_dir(struct device *dev,
				    struct kobject *glue_dir) {}
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#else
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static struct kobject *virtual_device_parent(struct device *dev)
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{
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	static struct kobject *virtual_dir = NULL;
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	if (!virtual_dir)
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		virtual_dir = kobject_create_and_add("virtual",
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						     &devices_kset->kobj);
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	return virtual_dir;
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}

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static struct kobject *get_device_parent(struct device *dev,
					 struct device *parent)
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{
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	int retval;

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	if (dev->class) {
		struct kobject *kobj = NULL;
		struct kobject *parent_kobj;
		struct kobject *k;

		/*
		 * If we have no parent, we live in "virtual".
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		 * Class-devices with a non class-device as parent, live
		 * in a "glue" directory to prevent namespace collisions.
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		 */
		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 */
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		k = kobject_create();
		if (!k)
			return NULL;
		k->kset = &dev->class->class_dirs;
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		retval = kobject_add(k, parent_kobj, "%s", dev->class->name);
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		if (retval < 0) {
			kobject_put(k);
			return NULL;
		}
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		/* do not emit an uevent for this simple "glue" directory */
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		return k;
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	}

	if (parent)
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		return &parent->kobj;
	return NULL;
}
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static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
627
{
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	/* see if we live in a "glue" directory */
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	if (!glue_dir || !dev->class ||
	    glue_dir->kset != &dev->class->class_dirs)
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		return;

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	kobject_put(glue_dir);
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}
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static void cleanup_device_parent(struct device *dev)
{
	cleanup_glue_dir(dev, dev->kobj.parent);
}
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#endif
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642
static void setup_parent(struct device *dev, struct device *parent)
643 644 645 646 647
{
	struct kobject *kobj;
	kobj = get_device_parent(dev, parent);
	if (kobj)
		dev->kobj.parent = kobj;
648 649
}

650 651 652 653 654 655
static int device_add_class_symlinks(struct device *dev)
{
	int error;

	if (!dev->class)
		return 0;
656

657 658 659 660
	error = sysfs_create_link(&dev->kobj, &dev->class->subsys.kobj,
				  "subsystem");
	if (error)
		goto out;
661 662 663

#ifdef CONFIG_SYSFS_DEPRECATED
	/* stacked class devices need a symlink in the class directory */
664
	if (dev->kobj.parent != &dev->class->subsys.kobj &&
665
	    device_is_not_partition(dev)) {
666 667 668 669 670
		error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
					  dev->bus_id);
		if (error)
			goto out_subsys;
	}
671

672
	if (dev->parent && device_is_not_partition(dev)) {
673 674
		struct device *parent = dev->parent;
		char *class_name;
675

676 677 678 679 680 681 682 683 684
		/*
		 * stacked class devices have the 'device' link
		 * pointing to the bus device instead of the parent
		 */
		while (parent->class && !parent->bus && parent->parent)
			parent = parent->parent;

		error = sysfs_create_link(&dev->kobj,
					  &parent->kobj,
685 686 687
					  "device");
		if (error)
			goto out_busid;
688 689 690 691 692 693 694 695 696

		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;
697 698 699 700
	}
	return 0;

out_device:
701
	if (dev->parent && device_is_not_partition(dev))
702 703
		sysfs_remove_link(&dev->kobj, "device");
out_busid:
704
	if (dev->kobj.parent != &dev->class->subsys.kobj &&
705
	    device_is_not_partition(dev))
706
		sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
707 708 709 710 711 712 713
#else
	/* link in the class directory pointing to the device */
	error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
				  dev->bus_id);
	if (error)
		goto out_subsys;

714
	if (dev->parent && device_is_not_partition(dev)) {
715 716 717 718 719 720 721 722 723 724 725
		error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
					  "device");
		if (error)
			goto out_busid;
	}
	return 0;

out_busid:
	sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
#endif

726 727 728 729 730 731 732 733 734 735
out_subsys:
	sysfs_remove_link(&dev->kobj, "subsystem");
out:
	return error;
}

static void device_remove_class_symlinks(struct device *dev)
{
	if (!dev->class)
		return;
736

737
#ifdef CONFIG_SYSFS_DEPRECATED
738
	if (dev->parent && device_is_not_partition(dev)) {
739 740 741 742 743 744 745 746 747
		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);
		}
		sysfs_remove_link(&dev->kobj, "device");
	}
748

749
	if (dev->kobj.parent != &dev->class->subsys.kobj &&
750
	    device_is_not_partition(dev))
751
		sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
752
#else
753
	if (dev->parent && device_is_not_partition(dev))
754 755 756 757 758
		sysfs_remove_link(&dev->kobj, "device");

	sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
#endif

759 760 761
	sysfs_remove_link(&dev->kobj, "subsystem");
}

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/**
763 764
 * device_add - add device to device hierarchy.
 * @dev: device.
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765
 *
766 767
 * This is part 2 of device_register(), though may be called
 * separately _iff_ device_initialize() has been called separately.
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768
 *
769 770 771
 * 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.
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 */
int device_add(struct device *dev)
{
	struct device *parent = NULL;
776
	struct class_interface *class_intf;
777 778
	int error;

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779
	dev = get_device(dev);
780 781
	if (!dev || !strlen(dev->bus_id)) {
		error = -EINVAL;
782
		goto Done;
783
	}
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784

785
	pr_debug("device: '%s': %s\n", dev->bus_id, __func__);
786

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787
	parent = get_device(dev->parent);
788
	setup_parent(dev, parent);
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789 790

	/* first, register with generic layer. */
791
	error = kobject_add(&dev->kobj, dev->kobj.parent, "%s", dev->bus_id);
792
	if (error)
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		goto Error;
794

795 796 797 798
	/* notify platform of device entry */
	if (platform_notify)
		platform_notify(dev);

799 800
	/* notify clients of device entry (new way) */
	if (dev->bus)
801
		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
802 803
					     BUS_NOTIFY_ADD_DEVICE, dev);

804
	error = device_create_file(dev, &uevent_attr);
805 806
	if (error)
		goto attrError;
807

808
	if (MAJOR(dev->devt)) {
809 810
		error = device_create_file(dev, &devt_attr);
		if (error)
811
			goto ueventattrError;
812 813
	}

814 815 816
	error = device_add_class_symlinks(dev);
	if (error)
		goto SymlinkError;
817 818
	error = device_add_attrs(dev);
	if (error)
819
		goto AttrsError;
820 821
	error = bus_add_device(dev);
	if (error)
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		goto BusError;
823 824 825
	error = device_pm_add(dev);
	if (error)
		goto PMError;
826
	kobject_uevent(&dev->kobj, KOBJ_ADD);
827
	bus_attach_device(dev);
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828
	if (parent)
829
		klist_add_tail(&dev->knode_parent, &parent->klist_children);
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830

831 832
	if (dev->class) {
		down(&dev->class->sem);
833
		/* tie the class to the device */
834
		list_add_tail(&dev->node, &dev->class->devices);
835 836 837 838 839

		/* 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);
840 841
		up(&dev->class->sem);
	}
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842 843 844 845
 Done:
	put_device(dev);
	return error;
 PMError:
846 847
	bus_remove_device(dev);
 BusError:
848
	if (dev->bus)
849
		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
850
					     BUS_NOTIFY_DEL_DEVICE, dev);
851
	device_remove_attrs(dev);
852
 AttrsError:
853 854
	device_remove_class_symlinks(dev);
 SymlinkError:
855 856
	if (MAJOR(dev->devt))
		device_remove_file(dev, &devt_attr);
857
 ueventattrError:
858
	device_remove_file(dev, &uevent_attr);
859
 attrError:
860
	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
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861 862
	kobject_del(&dev->kobj);
 Error:
863
	cleanup_device_parent(dev);
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864 865 866 867 868 869
	if (parent)
		put_device(parent);
	goto Done;
}

/**
870 871
 * device_register - register a device with the system.
 * @dev: pointer to the device structure
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872
 *
873 874 875 876 877 878
 * 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.
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879 880 881 882 883 884 885 886
 */
int device_register(struct device *dev)
{
	device_initialize(dev);
	return device_add(dev);
}

/**
887 888
 * get_device - increment reference count for device.
 * @dev: device.
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889
 *
890 891 892
 * 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.
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893
 */
894
struct device *get_device(struct device *dev)
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895 896 897 898 899
{
	return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
}

/**
900 901
 * put_device - decrement reference count.
 * @dev: device in question.
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902
 */
903
void put_device(struct device *dev)
L
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904
{
905
	/* might_sleep(); */
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906 907 908 909 910
	if (dev)
		kobject_put(&dev->kobj);
}

/**
911 912
 * device_del - delete device from system.
 * @dev: device.
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913
 *
914 915 916 917 918
 * 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.
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919
 *
920 921
 * NOTE: this should be called manually _iff_ device_add() was
 * also called manually.
L
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922
 */
923
void device_del(struct device *dev)
L
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924
{
925
	struct device *parent = dev->parent;
926
	struct class_interface *class_intf;
L
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927

928
	device_pm_remove(dev);
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929
	if (parent)
930
		klist_del(&dev->knode_parent);
931 932
	if (MAJOR(dev->devt))
		device_remove_file(dev, &devt_attr);
933
	if (dev->class) {
934
		device_remove_class_symlinks(dev);
935

936
		down(&dev->class->sem);
937 938 939 940 941
		/* notify any interfaces that the device is now gone */
		list_for_each_entry(class_intf, &dev->class->interfaces, node)
			if (class_intf->remove_dev)
				class_intf->remove_dev(dev, class_intf);
		/* remove the device from the class list */
942 943
		list_del_init(&dev->node);
		up(&dev->class->sem);
944
	}
945
	device_remove_file(dev, &uevent_attr);
946
	device_remove_attrs(dev);
947
	bus_remove_device(dev);
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948

949 950 951 952 953 954 955
	/*
	 * Some platform devices are driven without driver attached
	 * and managed resources may have been acquired.  Make sure
	 * all resources are released.
	 */
	devres_release_all(dev);

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956 957 958 959 960
	/* Notify the platform of the removal, in case they
	 * need to do anything...
	 */
	if (platform_notify_remove)
		platform_notify_remove(dev);
961
	if (dev->bus)
962
		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
963
					     BUS_NOTIFY_DEL_DEVICE, dev);
964
	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
965
	cleanup_device_parent(dev);
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966
	kobject_del(&dev->kobj);
967
	put_device(parent);
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968 969 970
}

/**
971 972
 * device_unregister - unregister device from system.
 * @dev: device going away.
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973
 *
974 975 976 977 978 979
 * We do this in two parts, like we do device_register(). First,
 * we remove it from all the subsystems with device_del(), then
 * we decrement the reference count via put_device(). If that
 * is the final reference count, the device will be cleaned up
 * via device_release() above. Otherwise, the structure will
 * stick around until the final reference to the device is dropped.
L
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980
 */
981
void device_unregister(struct device *dev)
L
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982
{
983
	pr_debug("device: '%s': %s\n", dev->bus_id, __func__);
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984 985 986 987
	device_del(dev);
	put_device(dev);
}

988
static struct device *next_device(struct klist_iter *i)
989
{
990
	struct klist_node *n = klist_next(i);
991 992 993
	return n ? container_of(n, struct device, knode_parent) : NULL;
}

L
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994
/**
995 996 997 998
 * device_for_each_child - device child iterator.
 * @parent: parent struct device.
 * @data: data for the callback.
 * @fn: function to be called for each device.
L
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999
 *
1000 1001
 * Iterate over @parent's child devices, and call @fn for each,
 * passing it @data.
L
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1002
 *
1003 1004
 * We check the return of @fn each time. If it returns anything
 * other than 0, we break out and return that value.
L
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1005
 */
1006 1007
int device_for_each_child(struct device *parent, void *data,
			  int (*fn)(struct device *dev, void *data))
L
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1008
{
1009
	struct klist_iter i;
1010
	struct device *child;
L
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1011 1012
	int error = 0;

1013 1014 1015 1016
	klist_iter_init(&parent->klist_children, &i);
	while ((child = next_device(&i)) && !error)
		error = fn(child, data);
	klist_iter_exit(&i);
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1017 1018 1019
	return error;
}

1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034
/**
 * device_find_child - device iterator for locating a particular device.
 * @parent: parent struct device
 * @data: Data to pass to match function
 * @match: Callback function to check device
 *
 * This is similar to the device_for_each_child() function above, but it
 * returns a reference to a device that is 'found' for later use, as
 * determined by the @match callback.
 *
 * The callback should return 0 if the device doesn't match and non-zero
 * if it does.  If the callback returns non-zero and a reference to the
 * current device can be obtained, this function will return to the caller
 * and not iterate over any more devices.
 */
1035 1036
struct device *device_find_child(struct device *parent, void *data,
				 int (*match)(struct device *dev, void *data))
1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051
{
	struct klist_iter i;
	struct device *child;

	if (!parent)
		return NULL;

	klist_iter_init(&parent->klist_children, &i);
	while ((child = next_device(&i)))
		if (match(child, data) && get_device(child))
			break;
	klist_iter_exit(&i);
	return child;
}

L
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1052 1053
int __init devices_init(void)
{
1054 1055 1056 1057
	devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
	if (!devices_kset)
		return -ENOMEM;
	return 0;
L
Linus Torvalds 已提交
1058 1059 1060
}

EXPORT_SYMBOL_GPL(device_for_each_child);
1061
EXPORT_SYMBOL_GPL(device_find_child);
L
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1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073

EXPORT_SYMBOL_GPL(device_initialize);
EXPORT_SYMBOL_GPL(device_add);
EXPORT_SYMBOL_GPL(device_register);

EXPORT_SYMBOL_GPL(device_del);
EXPORT_SYMBOL_GPL(device_unregister);
EXPORT_SYMBOL_GPL(get_device);
EXPORT_SYMBOL_GPL(put_device);

EXPORT_SYMBOL_GPL(device_create_file);
EXPORT_SYMBOL_GPL(device_remove_file);
1074 1075 1076 1077


static void device_create_release(struct device *dev)
{
1078
	pr_debug("device: '%s': %s\n", dev->bus_id, __func__);
1079 1080 1081 1082 1083
	kfree(dev);
}

/**
 * device_create - creates a device and registers it with sysfs
1084 1085 1086 1087 1088 1089 1090
 * @class: pointer to the struct class that this device should be registered to
 * @parent: pointer to the parent struct device of this new device, if any
 * @devt: the dev_t for the char device to be added
 * @fmt: string for the device's name
 *
 * This function can be used by char device classes.  A struct device
 * will be created in sysfs, registered to the specified class.
1091 1092 1093
 *
 * A "dev" file will be created, showing the dev_t for the device, if
 * the dev_t is not 0,0.
1094 1095 1096 1097
 * If a pointer to a parent struct device is passed in, the newly created
 * struct device will be a child of that device in sysfs.
 * The pointer to the struct device will be returned from the call.
 * Any further sysfs files that might be required can be created using this
1098 1099 1100 1101 1102 1103
 * pointer.
 *
 * Note: the struct class passed to this function must have previously
 * been created with a call to class_create().
 */
struct device *device_create(struct class *class, struct device *parent,
1104
			     dev_t devt, const char *fmt, ...)
1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138
{
	va_list args;
	struct device *dev = NULL;
	int retval = -ENODEV;

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

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

	dev->devt = devt;
	dev->class = class;
	dev->parent = parent;
	dev->release = device_create_release;

	va_start(args, fmt);
	vsnprintf(dev->bus_id, BUS_ID_SIZE, fmt, args);
	va_end(args);
	retval = device_register(dev);
	if (retval)
		goto error;

	return dev;

error:
	kfree(dev);
	return ERR_PTR(retval);
}
EXPORT_SYMBOL_GPL(device_create);

1139
static int __match_devt(struct device *dev, void *data)
1140
{
1141
	dev_t *devt = data;
1142

1143
	return dev->devt == *devt;
1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156
}

/**
 * device_destroy - removes a device that was created with device_create()
 * @class: 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 device that was created with a
 * call to device_create().
 */
void device_destroy(struct class *class, dev_t devt)
{
	struct device *dev;
1157

1158 1159 1160
	dev = class_find_device(class, &devt, __match_devt);
	if (dev) {
		put_device(dev);
1161
		device_unregister(dev);
1162
	}
1163 1164
}
EXPORT_SYMBOL_GPL(device_destroy);
1165 1166 1167 1168 1169 1170 1171 1172 1173 1174

/**
 * device_rename - renames a device
 * @dev: the pointer to the struct device to be renamed
 * @new_name: the new name of the device
 */
int device_rename(struct device *dev, char *new_name)
{
	char *old_class_name = NULL;
	char *new_class_name = NULL;
1175
	char *old_device_name = NULL;
1176 1177 1178 1179 1180 1181
	int error;

	dev = get_device(dev);
	if (!dev)
		return -EINVAL;

1182
	pr_debug("device: '%s': %s: renaming to '%s'\n", dev->bus_id,
1183
		 __func__, new_name);
1184

1185
#ifdef CONFIG_SYSFS_DEPRECATED
1186 1187
	if ((dev->class) && (dev->parent))
		old_class_name = make_class_name(dev->class->name, &dev->kobj);
1188
#endif
1189

1190 1191 1192 1193
	old_device_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL);
	if (!old_device_name) {
		error = -ENOMEM;
		goto out;
1194
	}
1195
	strlcpy(old_device_name, dev->bus_id, BUS_ID_SIZE);
1196 1197 1198
	strlcpy(dev->bus_id, new_name, BUS_ID_SIZE);

	error = kobject_rename(&dev->kobj, new_name);
1199 1200 1201 1202
	if (error) {
		strlcpy(dev->bus_id, old_device_name, BUS_ID_SIZE);
		goto out;
	}
1203

1204
#ifdef CONFIG_SYSFS_DEPRECATED
1205 1206 1207
	if (old_class_name) {
		new_class_name = make_class_name(dev->class->name, &dev->kobj);
		if (new_class_name) {
1208 1209 1210 1211
			error = sysfs_create_link(&dev->parent->kobj,
						  &dev->kobj, new_class_name);
			if (error)
				goto out;
1212 1213 1214
			sysfs_remove_link(&dev->parent->kobj, old_class_name);
		}
	}
1215
#else
1216
	if (dev->class) {
1217 1218 1219 1220 1221
		sysfs_remove_link(&dev->class->subsys.kobj, old_device_name);
		error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
					  dev->bus_id);
		if (error) {
			dev_err(dev, "%s: sysfs_create_symlink failed (%d)\n",
1222
				__func__, error);
1223
		}
1224
	}
1225 1226
#endif

1227
out:
1228 1229 1230
	put_device(dev);

	kfree(new_class_name);
1231
	kfree(old_class_name);
1232
	kfree(old_device_name);
1233 1234 1235

	return error;
}
1236
EXPORT_SYMBOL_GPL(device_rename);
1237 1238 1239 1240 1241

static int device_move_class_links(struct device *dev,
				   struct device *old_parent,
				   struct device *new_parent)
{
1242
	int error = 0;
1243 1244 1245 1246 1247
#ifdef CONFIG_SYSFS_DEPRECATED
	char *class_name;

	class_name = make_class_name(dev->class->name, &dev->kobj);
	if (!class_name) {
1248
		error = -ENOMEM;
1249 1250 1251 1252 1253 1254
		goto out;
	}
	if (old_parent) {
		sysfs_remove_link(&dev->kobj, "device");
		sysfs_remove_link(&old_parent->kobj, class_name);
	}
1255 1256 1257 1258 1259 1260 1261 1262 1263
	if (new_parent) {
		error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
					  "device");
		if (error)
			goto out;
		error = sysfs_create_link(&new_parent->kobj, &dev->kobj,
					  class_name);
		if (error)
			sysfs_remove_link(&dev->kobj, "device");
1264
	} else
1265
		error = 0;
1266 1267 1268 1269
out:
	kfree(class_name);
	return error;
#else
1270 1271 1272 1273 1274 1275
	if (old_parent)
		sysfs_remove_link(&dev->kobj, "device");
	if (new_parent)
		error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
					  "device");
	return error;
1276 1277 1278 1279 1280 1281
#endif
}

/**
 * device_move - moves a device to a new parent
 * @dev: the pointer to the struct device to be moved
1282
 * @new_parent: the new parent of the device (can by NULL)
1283 1284 1285 1286 1287
 */
int device_move(struct device *dev, struct device *new_parent)
{
	int error;
	struct device *old_parent;
1288
	struct kobject *new_parent_kobj;
1289 1290 1291 1292 1293 1294

	dev = get_device(dev);
	if (!dev)
		return -EINVAL;

	new_parent = get_device(new_parent);
1295
	new_parent_kobj = get_device_parent(dev, new_parent);
1296

1297
	pr_debug("device: '%s': %s: moving to '%s'\n", dev->bus_id,
1298
		 __func__, new_parent ? new_parent->bus_id : "<NULL>");
1299
	error = kobject_move(&dev->kobj, new_parent_kobj);
1300
	if (error) {
1301
		cleanup_glue_dir(dev, new_parent_kobj);
1302 1303 1304 1305 1306 1307
		put_device(new_parent);
		goto out;
	}
	old_parent = dev->parent;
	dev->parent = new_parent;
	if (old_parent)
1308
		klist_remove(&dev->knode_parent);
1309 1310
	if (new_parent)
		klist_add_tail(&dev->knode_parent, &new_parent->klist_children);
1311 1312 1313 1314 1315 1316 1317
	if (!dev->class)
		goto out_put;
	error = device_move_class_links(dev, old_parent, new_parent);
	if (error) {
		/* We ignore errors on cleanup since we're hosed anyway... */
		device_move_class_links(dev, new_parent, old_parent);
		if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1318 1319
			if (new_parent)
				klist_remove(&dev->knode_parent);
1320 1321 1322 1323
			if (old_parent)
				klist_add_tail(&dev->knode_parent,
					       &old_parent->klist_children);
		}
1324
		cleanup_glue_dir(dev, new_parent_kobj);
1325 1326 1327 1328 1329 1330 1331 1332 1333 1334
		put_device(new_parent);
		goto out;
	}
out_put:
	put_device(old_parent);
out:
	put_device(dev);
	return error;
}
EXPORT_SYMBOL_GPL(device_move);
1335 1336 1337 1338 1339 1340

/**
 * device_shutdown - call ->shutdown() on each device to shutdown.
 */
void device_shutdown(void)
{
1341
	struct device *dev, *devn;
1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353

	list_for_each_entry_safe_reverse(dev, devn, &devices_kset->list,
				kobj.entry) {
		if (dev->bus && dev->bus->shutdown) {
			dev_dbg(dev, "shutdown\n");
			dev->bus->shutdown(dev);
		} else if (dev->driver && dev->driver->shutdown) {
			dev_dbg(dev, "shutdown\n");
			dev->driver->shutdown(dev);
		}
	}
}