core.c 33.5 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 <asm/semaphore.h>

#include "base.h"
#include "power/power.h"

int (*platform_notify)(struct device * dev) = NULL;
int (*platform_notify_remove)(struct device * dev) = NULL;

/*
 * sysfs bindings for devices.
 */

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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)

static ssize_t
dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
{
	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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	return ret;
}

static ssize_t
dev_attr_store(struct kobject * kobj, struct attribute * attr,
	       const char * buf, size_t count)
{
	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.
 */
static void device_release(struct kobject * kobj)
{
	struct device * dev = to_dev(kobj);

	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 {
		printk(KERN_ERR "Device '%s' does not have a release() function, "
			"it is broken and must be fixed.\n",
			dev->bus_id);
		WARN_ON(1);
	}
}

static struct kobj_type ktype_device = {
	.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);

	if (ktype == &ktype_device) {
		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)
			pr_debug ("%s: bus uevent() returned %d\n",
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				  __FUNCTION__, retval);
	}

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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)
			pr_debug("%s: class uevent() returned %d\n",
				 __FUNCTION__, retval);
	}

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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)
			pr_debug("%s: dev_type uevent() returned %d\n",
				 __FUNCTION__, 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;
	if (!top_kobj->kset && top_kobj->parent) {
		do {
			top_kobj = top_kobj->parent;
		} while (!top_kobj->kset && top_kobj->parent);
	}
	if (!top_kobj->kset)
		goto out;
	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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	size_t len = count;
	enum kobject_action action;

	if (len && buf[len-1] == '\n')
		len--;

	for (action = 0; action < KOBJ_MAX; action++) {
		if (strncmp(kobject_actions[action], buf, len) != 0)
			continue;
		if (kobject_actions[action][len] != '\0')
			continue;
		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]);
				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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/*
 *	devices_subsys - structure to be registered with kobject core.
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 */

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decl_subsys(devices, &ktype_device, &device_uevent_ops);
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/**
 *	device_create_file - create sysfs attribute file for device.
 *	@dev:	device.
 *	@attr:	device attribute descriptor.
 */

int device_create_file(struct device * dev, struct device_attribute * attr)
{
	int error = 0;
	if (get_device(dev)) {
		error = sysfs_create_file(&dev->kobj, &attr->attr);
		put_device(dev);
	}
	return error;
}

/**
 *	device_remove_file - remove sysfs attribute file.
 *	@dev:	device.
 *	@attr:	device attribute descriptor.
 */

void device_remove_file(struct device * dev, struct device_attribute * attr)
{
	if (get_device(dev)) {
		sysfs_remove_file(&dev->kobj, &attr->attr);
		put_device(dev);
	}
}

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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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/**
 *	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);
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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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	/*
	 * 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))
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		return &dev->class->subsys.kobj;
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	else if (parent)
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		return &parent->kobj;
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	return NULL;
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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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573
	if (!virtual_dir)
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		virtual_dir = kobject_add_dir(&devices_subsys.kobj, "virtual");
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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)
581
{
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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".
		 * 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)
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		return &parent->kobj;
	return NULL;
}
#endif
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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;
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	return 0;
}

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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;
	}
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	if (dev->parent) {
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#ifdef CONFIG_SYSFS_DEPRECATED
		{
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			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);
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			if (class_name)
				error = sysfs_create_link(&dev->parent->kobj,
							&dev->kobj, class_name);
			kfree(class_name);
			if (error)
				goto out_device;
		}
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#else
		error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
					  "device");
		if (error)
			goto out_busid;
685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723
#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");
}

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/**
 *	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;
738
	struct class_interface *class_intf;
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	int error = -EINVAL;

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

745
	pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);
746

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	parent = get_device(dev->parent);
748 749 750
	error = setup_parent(dev, parent);
	if (error)
		goto Error;
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	/* first, register with generic layer. */
	kobject_set_name(&dev->kobj, "%s", dev->bus_id);
754 755
	error = kobject_add(&dev->kobj);
	if (error)
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		goto Error;
757

758 759 760 761
	/* notify platform of device entry */
	if (platform_notify)
		platform_notify(dev);

762 763 764 765 766
	/* notify clients of device entry (new way) */
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->bus_notifier,
					     BUS_NOTIFY_ADD_DEVICE, dev);

767
	error = device_create_file(dev, &uevent_attr);
768 769
	if (error)
		goto attrError;
770

771
	if (MAJOR(dev->devt)) {
772 773
		error = device_create_file(dev, &devt_attr);
		if (error)
774
			goto ueventattrError;
775 776
	}

777 778 779
	error = device_add_class_symlinks(dev);
	if (error)
		goto SymlinkError;
780 781
	error = device_add_attrs(dev);
	if (error)
782
		goto AttrsError;
783 784
	error = device_pm_add(dev);
	if (error)
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		goto PMError;
786 787
	error = bus_add_device(dev);
	if (error)
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		goto BusError;
789
	kobject_uevent(&dev->kobj, KOBJ_ADD);
790
	bus_attach_device(dev);
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	if (parent)
792
		klist_add_tail(&dev->knode_parent, &parent->klist_children);
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794 795
	if (dev->class) {
		down(&dev->class->sem);
796
		/* tie the class to the device */
797
		list_add_tail(&dev->node, &dev->class->devices);
798 799 800 801 802

		/* 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);
803 804
		up(&dev->class->sem);
	}
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 Done:
	put_device(dev);
	return error;
 BusError:
	device_pm_remove(dev);
 PMError:
811 812 813
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->bus_notifier,
					     BUS_NOTIFY_DEL_DEVICE, dev);
814
	device_remove_attrs(dev);
815
 AttrsError:
816 817
	device_remove_class_symlinks(dev);
 SymlinkError:
818 819
	if (MAJOR(dev->devt))
		device_remove_file(dev, &devt_attr);
820 821 822 823 824

	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. */
825 826
		if (dev->kobj.parent != &dev->class->subsys.kobj)
			sysfs_remove_link(&dev->class->subsys.kobj,
827 828
					  dev->bus_id);
		if (parent) {
829
#ifdef CONFIG_SYSFS_DEPRECATED
830 831 832 833 834 835
			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);
836
#endif
837 838 839
			sysfs_remove_link(&dev->kobj, "device");
		}
	}
840
 ueventattrError:
841
	device_remove_file(dev, &uevent_attr);
842
 attrError:
843
	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
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	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;
914
	struct class_interface *class_intf;
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	if (parent)
917
		klist_del(&dev->knode_parent);
918 919
	if (MAJOR(dev->devt))
		device_remove_file(dev, &devt_attr);
920 921
	if (dev->class) {
		sysfs_remove_link(&dev->kobj, "subsystem");
922 923
		/* If this is not a "fake" compatible device, remove the
		 * symlink from the class to the device. */
924 925
		if (dev->kobj.parent != &dev->class->subsys.kobj)
			sysfs_remove_link(&dev->class->subsys.kobj,
926
					  dev->bus_id);
927
		if (parent) {
928
#ifdef CONFIG_SYSFS_DEPRECATED
929 930
			char *class_name = make_class_name(dev->class->name,
							   &dev->kobj);
931 932 933
			if (class_name)
				sysfs_remove_link(&dev->parent->kobj,
						  class_name);
934
			kfree(class_name);
935
#endif
936
			sysfs_remove_link(&dev->kobj, "device");
937
		}
938

939
		down(&dev->class->sem);
940 941 942 943 944
		/* 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 */
945 946
		list_del_init(&dev->node);
		up(&dev->class->sem);
947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971

		/* If we live in a parent class-directory, unreference it */
		if (dev->kobj.parent->kset == &dev->class->class_dirs) {
			struct device *d;
			int other = 0;

			/*
			 * if we are the last child of our class, delete
			 * our class-directory at this parent
			 */
			down(&dev->class->sem);
			list_for_each_entry(d, &dev->class->devices, node) {
				if (d == dev)
					continue;
				if (d->kobj.parent == dev->kobj.parent) {
					other = 1;
					break;
				}
			}
			if (!other)
				kobject_del(dev->kobj.parent);

			kobject_put(dev->kobj.parent);
			up(&dev->class->sem);
		}
972
	}
973
	device_remove_file(dev, &uevent_attr);
974
	device_remove_attrs(dev);
975
	bus_remove_device(dev);
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977 978 979 980 981 982 983
	/*
	 * 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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	/* Notify the platform of the removal, in case they
	 * need to do anything...
	 */
	if (platform_notify_remove)
		platform_notify_remove(dev);
989 990 991
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->bus_notifier,
					     BUS_NOTIFY_DEL_DEVICE, dev);
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	device_pm_remove(dev);
993
	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
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	kobject_del(&dev->kobj);
	if (parent)
		put_device(parent);
}

/**
 *	device_unregister - unregister device from system.
 *	@dev:	device going away.
 *
 *	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.
 */
void device_unregister(struct device * dev)
{
	pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id);
	device_del(dev);
	put_device(dev);
}


1018 1019 1020 1021 1022 1023
static struct device * next_device(struct klist_iter * i)
{
	struct klist_node * n = klist_next(i);
	return n ? container_of(n, struct device, knode_parent) : NULL;
}

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/**
 *	device_for_each_child - device child iterator.
1026
 *	@parent: parent struct device.
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1027 1028 1029
 *	@data:	data for the callback.
 *	@fn:	function to be called for each device.
 *
1030
 *	Iterate over @parent's child devices, and call @fn for each,
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 *	passing it @data.
 *
 *	We check the return of @fn each time. If it returns anything
 *	other than 0, we break out and return that value.
 */
1036
int device_for_each_child(struct device * parent, void * data,
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1037 1038
		     int (*fn)(struct device *, void *))
{
1039
	struct klist_iter i;
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1040 1041 1042
	struct device * child;
	int error = 0;

1043 1044 1045 1046
	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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1047 1048 1049
	return error;
}

1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081
/**
 * 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.
 */
struct device * device_find_child(struct device *parent, void *data,
				  int (*match)(struct device *, void *))
{
	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;
}

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1082 1083 1084 1085 1086 1087
int __init devices_init(void)
{
	return subsystem_register(&devices_subsys);
}

EXPORT_SYMBOL_GPL(device_for_each_child);
1088
EXPORT_SYMBOL_GPL(device_find_child);
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1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100

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);
1101 1102 1103 1104 1105 1106 1107 1108 1109 1110


static void device_create_release(struct device *dev)
{
	pr_debug("%s called for %s\n", __FUNCTION__, dev->bus_id);
	kfree(dev);
}

/**
 * device_create - creates a device and registers it with sysfs
1111 1112 1113 1114 1115 1116 1117
 * @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.
1118 1119 1120
 *
 * A "dev" file will be created, showing the dev_t for the device, if
 * the dev_t is not 0,0.
1121 1122 1123 1124
 * 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
1125 1126 1127 1128 1129 1130
 * 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,
1131
			     dev_t devt, const char *fmt, ...)
1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167
{
	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);

/**
 * device_destroy - removes a device that was created with device_create()
1168 1169
 * @class: pointer to the struct class that this device was registered with
 * @devt: the dev_t of the device that was previously registered
1170
 *
1171 1172
 * This call unregisters and cleans up a device that was created with a
 * call to device_create().
1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187
 */
void device_destroy(struct class *class, dev_t devt)
{
	struct device *dev = NULL;
	struct device *dev_tmp;

	down(&class->sem);
	list_for_each_entry(dev_tmp, &class->devices, node) {
		if (dev_tmp->devt == devt) {
			dev = dev_tmp;
			break;
		}
	}
	up(&class->sem);

1188
	if (dev)
1189 1190 1191
		device_unregister(dev);
}
EXPORT_SYMBOL_GPL(device_destroy);
1192 1193 1194 1195 1196 1197 1198 1199 1200 1201

/**
 * 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;
1202
	char *old_device_name = NULL;
1203 1204 1205 1206 1207 1208 1209 1210
	int error;

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

	pr_debug("DEVICE: renaming '%s' to '%s'\n", dev->bus_id, new_name);

1211
#ifdef CONFIG_SYSFS_DEPRECATED
1212 1213
	if ((dev->class) && (dev->parent))
		old_class_name = make_class_name(dev->class->name, &dev->kobj);
1214
#endif
1215

1216 1217 1218 1219
	old_device_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL);
	if (!old_device_name) {
		error = -ENOMEM;
		goto out;
1220
	}
1221
	strlcpy(old_device_name, dev->bus_id, BUS_ID_SIZE);
1222 1223 1224
	strlcpy(dev->bus_id, new_name, BUS_ID_SIZE);

	error = kobject_rename(&dev->kobj, new_name);
1225 1226 1227 1228
	if (error) {
		strlcpy(dev->bus_id, old_device_name, BUS_ID_SIZE);
		goto out;
	}
1229

1230
#ifdef CONFIG_SYSFS_DEPRECATED
1231 1232 1233
	if (old_class_name) {
		new_class_name = make_class_name(dev->class->name, &dev->kobj);
		if (new_class_name) {
1234 1235 1236 1237
			error = sysfs_create_link(&dev->parent->kobj,
						  &dev->kobj, new_class_name);
			if (error)
				goto out;
1238 1239 1240
			sysfs_remove_link(&dev->parent->kobj, old_class_name);
		}
	}
1241 1242
#endif

1243
	if (dev->class) {
1244 1245 1246 1247 1248 1249 1250 1251
		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) {
			/* Uh... how to unravel this if restoring can fail? */
			dev_err(dev, "%s: sysfs_create_symlink failed (%d)\n",
				__FUNCTION__, error);
		}
1252
	}
1253
out:
1254 1255 1256
	put_device(dev);

	kfree(new_class_name);
1257
	kfree(old_class_name);
1258
	kfree(old_device_name);
1259 1260 1261

	return error;
}
1262
EXPORT_SYMBOL_GPL(device_rename);
1263 1264 1265 1266 1267

static int device_move_class_links(struct device *dev,
				   struct device *old_parent,
				   struct device *new_parent)
{
1268
	int error = 0;
1269 1270 1271 1272 1273
#ifdef CONFIG_SYSFS_DEPRECATED
	char *class_name;

	class_name = make_class_name(dev->class->name, &dev->kobj);
	if (!class_name) {
1274
		error = -ENOMEM;
1275 1276 1277 1278 1279 1280
		goto out;
	}
	if (old_parent) {
		sysfs_remove_link(&dev->kobj, "device");
		sysfs_remove_link(&old_parent->kobj, class_name);
	}
1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292
	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");
	}
	else
		error = 0;
1293 1294 1295 1296
out:
	kfree(class_name);
	return error;
#else
1297 1298 1299 1300 1301 1302
	if (old_parent)
		sysfs_remove_link(&dev->kobj, "device");
	if (new_parent)
		error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
					  "device");
	return error;
1303 1304 1305 1306 1307 1308
#endif
}

/**
 * device_move - moves a device to a new parent
 * @dev: the pointer to the struct device to be moved
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 * @new_parent: the new parent of the device (can by NULL)
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 */
int device_move(struct device *dev, struct device *new_parent)
{
	int error;
	struct device *old_parent;
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	struct kobject *new_parent_kobj;
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	dev = get_device(dev);
	if (!dev)
		return -EINVAL;

	new_parent = get_device(new_parent);
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	new_parent_kobj = get_device_parent (dev, new_parent);
	if (IS_ERR(new_parent_kobj)) {
		error = PTR_ERR(new_parent_kobj);
		put_device(new_parent);
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		goto out;
	}
	pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id,
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		 new_parent ? new_parent->bus_id : "<NULL>");
	error = kobject_move(&dev->kobj, new_parent_kobj);
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	if (error) {
		put_device(new_parent);
		goto out;
	}
	old_parent = dev->parent;
	dev->parent = new_parent;
	if (old_parent)
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		klist_remove(&dev->knode_parent);
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	if (new_parent)
		klist_add_tail(&dev->knode_parent, &new_parent->klist_children);
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	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)) {
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			if (new_parent)
				klist_remove(&dev->knode_parent);
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			if (old_parent)
				klist_add_tail(&dev->knode_parent,
					       &old_parent->klist_children);
		}
		put_device(new_parent);
		goto out;
	}
out_put:
	put_device(old_parent);
out:
	put_device(dev);
	return error;
}

EXPORT_SYMBOL_GPL(device_move);