core.c 28.9 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;

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/*
 * Detect the LANANA-assigned LOCAL/EXPERIMENTAL majors
 */
bool is_lanana_major(unsigned int major)
{
	if (major >= 60 && major <= 63)
		return 1;
	if (major >= 120 && major <= 127)
		return 1;
	if (major >= 240 && major <= 254)
		return 1;
	return 0;
}

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/*
 * 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 :
			(dev->bus ? dev->bus->name : "");
}
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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);
		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, char **envp,
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			int num_envp, char *buffer, int buffer_size)
{
	struct device *dev = to_dev(kobj);
	int i = 0;
	int length = 0;
	int retval = 0;

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	/* add the major/minor if present */
	if (MAJOR(dev->devt)) {
		add_uevent_var(envp, num_envp, &i,
			       buffer, buffer_size, &length,
			       "MAJOR=%u", MAJOR(dev->devt));
		add_uevent_var(envp, num_envp, &i,
			       buffer, buffer_size, &length,
			       "MINOR=%u", MINOR(dev->devt));
	}

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	if (dev->driver)
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		add_uevent_var(envp, num_envp, &i,
			       buffer, buffer_size, &length,
			       "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);
			add_uevent_var(envp, num_envp, &i,
				       buffer, buffer_size, &length,
				       "PHYSDEVPATH=%s", path);
			kfree(path);

			add_uevent_var(envp, num_envp, &i,
				       buffer, buffer_size, &length,
				       "PHYSDEVBUS=%s", parent->bus->name);

			if (parent->driver)
				add_uevent_var(envp, num_envp, &i,
					       buffer, buffer_size, &length,
					       "PHYSDEVDRIVER=%s", parent->driver->name);
		}
	} else if (dev->bus) {
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		add_uevent_var(envp, num_envp, &i,
			       buffer, buffer_size, &length,
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			       "PHYSDEVBUS=%s", dev->bus->name);

		if (dev->driver)
			add_uevent_var(envp, num_envp, &i,
				       buffer, buffer_size, &length,
				       "PHYSDEVDRIVER=%s", dev->driver->name);
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	}
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#endif
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	/* terminate, set to next free slot, shrink available space */
	envp[i] = NULL;
	envp = &envp[i];
	num_envp -= i;
	buffer = &buffer[length];
	buffer_size -= length;

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	if (dev->bus && dev->bus->uevent) {
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		/* have the bus specific function add its stuff */
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		retval = dev->bus->uevent(dev, envp, num_envp, buffer, buffer_size);
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		if (retval)
			pr_debug ("%s: bus uevent() returned %d\n",
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				  __FUNCTION__, retval);
	}

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	if (dev->class && dev->class->dev_uevent) {
		/* have the class specific function add its stuff */
		retval = dev->class->dev_uevent(dev, envp, num_envp, buffer, buffer_size);
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		if (retval)
			pr_debug("%s: class uevent() returned %d\n",
				 __FUNCTION__, retval);
	}

	if (dev->type && dev->type->uevent) {
		/* have the device type specific fuction add its stuff */
		retval = dev->type->uevent(dev, envp, num_envp, buffer, buffer_size);
		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 store_uevent(struct device *dev, struct device_attribute *attr,
			    const char *buf, size_t count)
{
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	kobject_uevent(&dev->kobj, KOBJ_ADD);
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	return count;
}

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static int device_add_groups(struct device *dev)
{
	int i;
	int error = 0;

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

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

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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 = 0;
	int i;

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	if (class && class->dev_attrs) {
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		for (i = 0; attr_name(class->dev_attrs[i]); i++) {
			error = device_create_file(dev, &class->dev_attrs[i]);
			if (error)
				break;
		}
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		if (error)
			while (--i >= 0)
				device_remove_file(dev, &class->dev_attrs[i]);
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	}
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	if (type && type->attrs) {
		for (i = 0; attr_name(type->attrs[i]); i++) {
			error = device_create_file(dev, &type->attrs[i]);
			if (error)
				break;
		}
		if (error)
			while (--i >= 0)
				device_remove_file(dev, &type->attrs[i]);
	}

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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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	int i;

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	if (class && class->dev_attrs) {
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		for (i = 0; attr_name(class->dev_attrs[i]); i++)
			device_remove_file(dev, &class->dev_attrs[i]);
	}
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	if (type && type->attrs) {
		for (i = 0; attr_name(type->attrs[i]); i++)
			device_remove_file(dev, &type->attrs[i]);
	}
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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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/*
 *	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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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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{
	/* Set the parent to the class, not the parent device */
	/* this keeps sysfs from having a symlink to make old udevs happy */
	if (dev->class)
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		return &dev->class->subsys.kset.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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{
	if (!dev->class)
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		return ERR_PTR(-ENODEV);
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	if (!dev->class->virtual_dir) {
		static struct kobject *virtual_dir = NULL;

		if (!virtual_dir)
			virtual_dir = kobject_add_dir(&devices_subsys.kset.kobj, "virtual");
		dev->class->virtual_dir = kobject_add_dir(virtual_dir, dev->class->name);
	}

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	return dev->class->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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{
	/* if this is a class device, and has no parent, create one */
	if ((dev->class) && (parent == NULL)) {
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		return virtual_device_parent(dev);
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	} else if (parent)
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		return &parent->kobj;
	return NULL;
}
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#endif
static int setup_parent(struct device *dev, struct device *parent)
{
	struct kobject *kobj;
	kobj = get_device_parent(dev, parent);
	if (IS_ERR(kobj))
		return PTR_ERR(kobj);
	if (kobj)
		dev->kobj.parent = kobj;
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	return 0;
}

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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;
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	char *class_name = NULL;
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	struct class_interface *class_intf;
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	int error = -EINVAL;

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

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

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	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);
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	error = kobject_add(&dev->kobj);
	if (error)
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		goto Error;
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	/* notify platform of device entry */
	if (platform_notify)
		platform_notify(dev);

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

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	dev->uevent_attr.attr.name = "uevent";
	dev->uevent_attr.attr.mode = S_IWUSR;
	if (dev->driver)
		dev->uevent_attr.attr.owner = dev->driver->owner;
	dev->uevent_attr.store = store_uevent;
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	error = device_create_file(dev, &dev->uevent_attr);
	if (error)
		goto attrError;
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	if (MAJOR(dev->devt)) {
		struct device_attribute *attr;
		attr = kzalloc(sizeof(*attr), GFP_KERNEL);
		if (!attr) {
			error = -ENOMEM;
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			goto ueventattrError;
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		}
		attr->attr.name = "dev";
		attr->attr.mode = S_IRUGO;
		if (dev->driver)
			attr->attr.owner = dev->driver->owner;
		attr->show = show_dev;
		error = device_create_file(dev, attr);
		if (error) {
			kfree(attr);
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			goto ueventattrError;
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		}

		dev->devt_attr = attr;
	}

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	if (dev->class) {
		sysfs_create_link(&dev->kobj, &dev->class->subsys.kset.kobj,
				  "subsystem");
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		/* 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.kset.kobj)
			sysfs_create_link(&dev->class->subsys.kset.kobj,
					  &dev->kobj, dev->bus_id);
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#ifdef CONFIG_SYSFS_DEPRECATED
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		if (parent) {
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			sysfs_create_link(&dev->kobj, &dev->parent->kobj,
							"device");
			class_name = make_class_name(dev->class->name,
							&dev->kobj);
			if (class_name)
				sysfs_create_link(&dev->parent->kobj,
						  &dev->kobj, class_name);
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		}
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#endif
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	}
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	if ((error = device_add_attrs(dev)))
		goto AttrsError;
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	if ((error = device_add_groups(dev)))
		goto GroupError;
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	if ((error = device_pm_add(dev)))
		goto PMError;
	if ((error = bus_add_device(dev)))
		goto BusError;
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	if (!dev->uevent_suppress)
		kobject_uevent(&dev->kobj, KOBJ_ADD);
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	if ((error = bus_attach_device(dev)))
		goto AttachError;
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	if (parent)
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		klist_add_tail(&dev->knode_parent, &parent->klist_children);
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	if (dev->class) {
		down(&dev->class->sem);
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		/* tie the class to the device */
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		list_add_tail(&dev->node, &dev->class->devices);
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		/* 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);
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		up(&dev->class->sem);
	}
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 Done:
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 	kfree(class_name);
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	put_device(dev);
	return error;
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 AttachError:
	bus_remove_device(dev);
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 BusError:
	device_pm_remove(dev);
 PMError:
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	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->bus_notifier,
					     BUS_NOTIFY_DEL_DEVICE, dev);
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	device_remove_groups(dev);
 GroupError:
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	device_remove_attrs(dev);
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 AttrsError:
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	if (dev->devt_attr) {
		device_remove_file(dev, dev->devt_attr);
		kfree(dev->devt_attr);
	}
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	if (dev->class) {
		sysfs_remove_link(&dev->kobj, "subsystem");
		/* If this is not a "fake" compatible device, remove the
		 * symlink from the class to the device. */
		if (dev->kobj.parent != &dev->class->subsys.kset.kobj)
			sysfs_remove_link(&dev->class->subsys.kset.kobj,
					  dev->bus_id);
#ifdef CONFIG_SYSFS_DEPRECATED
		if (parent) {
			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);
			sysfs_remove_link(&dev->kobj, "device");
		}
#endif

		down(&dev->class->sem);
		/* 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 */
		list_del_init(&dev->node);
		up(&dev->class->sem);
	}
675 676
 ueventattrError:
	device_remove_file(dev, &dev->uevent_attr);
677
 attrError:
678
	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;
749
	struct class_interface *class_intf;
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	if (parent)
752
		klist_del(&dev->knode_parent);
753
	if (dev->devt_attr) {
754
		device_remove_file(dev, dev->devt_attr);
755 756
		kfree(dev->devt_attr);
	}
757 758
	if (dev->class) {
		sysfs_remove_link(&dev->kobj, "subsystem");
759 760 761 762 763
		/* If this is not a "fake" compatible device, remove the
		 * symlink from the class to the device. */
		if (dev->kobj.parent != &dev->class->subsys.kset.kobj)
			sysfs_remove_link(&dev->class->subsys.kset.kobj,
					  dev->bus_id);
764
#ifdef CONFIG_SYSFS_DEPRECATED
765
		if (parent) {
766 767
			char *class_name = make_class_name(dev->class->name,
							   &dev->kobj);
768 769 770
			if (class_name)
				sysfs_remove_link(&dev->parent->kobj,
						  class_name);
771 772
			kfree(class_name);
			sysfs_remove_link(&dev->kobj, "device");
773
		}
774 775
#endif

776
		down(&dev->class->sem);
777 778 779 780 781
		/* 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 */
782 783
		list_del_init(&dev->node);
		up(&dev->class->sem);
784
	}
785
	device_remove_file(dev, &dev->uevent_attr);
786
	device_remove_groups(dev);
787
	device_remove_attrs(dev);
788
	bus_remove_device(dev);
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790 791 792 793 794 795 796
	/*
	 * 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);
802 803 804
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->bus_notifier,
					     BUS_NOTIFY_DEL_DEVICE, dev);
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	device_pm_remove(dev);
806
	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);
}


831 832 833 834 835 836
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.
839
 *	@parent: parent struct device.
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 *	@data:	data for the callback.
 *	@fn:	function to be called for each device.
 *
843
 *	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.
 */
849
int device_for_each_child(struct device * parent, void * data,
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		     int (*fn)(struct device *, void *))
{
852
	struct klist_iter i;
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	struct device * child;
	int error = 0;

856 857 858 859
	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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	return error;
}

863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894
/**
 * 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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int __init devices_init(void)
{
	return subsystem_register(&devices_subsys);
}

EXPORT_SYMBOL_GPL(device_for_each_child);
901
EXPORT_SYMBOL_GPL(device_find_child);
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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);
914 915 916 917 918 919 920 921 922 923


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
924 925 926 927 928 929 930
 * @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.
931 932 933
 *
 * A "dev" file will be created, showing the dev_t for the device, if
 * the dev_t is not 0,0.
934 935 936 937
 * 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
938 939 940 941 942 943
 * 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,
944
			     dev_t devt, const char *fmt, ...)
945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980
{
	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()
981 982
 * @class: pointer to the struct class that this device was registered with
 * @devt: the dev_t of the device that was previously registered
983
 *
984 985
 * This call unregisters and cleans up a device that was created with a
 * call to device_create().
986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000
 */
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);

1001
	if (dev)
1002 1003 1004
		device_unregister(dev);
}
EXPORT_SYMBOL_GPL(device_destroy);
1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023

/**
 * 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;
	char *old_symlink_name = NULL;
	int error;

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

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

1024
#ifdef CONFIG_SYSFS_DEPRECATED
1025 1026
	if ((dev->class) && (dev->parent))
		old_class_name = make_class_name(dev->class->name, &dev->kobj);
1027
#endif
1028 1029 1030

	if (dev->class) {
		old_symlink_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL);
1031 1032 1033 1034
		if (!old_symlink_name) {
			error = -ENOMEM;
			goto out_free_old_class;
		}
1035 1036 1037 1038 1039 1040 1041
		strlcpy(old_symlink_name, dev->bus_id, BUS_ID_SIZE);
	}

	strlcpy(dev->bus_id, new_name, BUS_ID_SIZE);

	error = kobject_rename(&dev->kobj, new_name);

1042
#ifdef CONFIG_SYSFS_DEPRECATED
1043 1044 1045 1046 1047 1048 1049 1050
	if (old_class_name) {
		new_class_name = make_class_name(dev->class->name, &dev->kobj);
		if (new_class_name) {
			sysfs_create_link(&dev->parent->kobj, &dev->kobj,
					  new_class_name);
			sysfs_remove_link(&dev->parent->kobj, old_class_name);
		}
	}
1051 1052
#endif

1053 1054 1055 1056 1057 1058 1059 1060 1061 1062
	if (dev->class) {
		sysfs_remove_link(&dev->class->subsys.kset.kobj,
				  old_symlink_name);
		sysfs_create_link(&dev->class->subsys.kset.kobj, &dev->kobj,
				  dev->bus_id);
	}
	put_device(dev);

	kfree(new_class_name);
	kfree(old_symlink_name);
1063 1064
 out_free_old_class:
	kfree(old_class_name);
1065 1066 1067

	return error;
}
1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079


static int device_move_class_links(struct device *dev,
				   struct device *old_parent,
				   struct device *new_parent)
{
#ifdef CONFIG_SYSFS_DEPRECATED
	int error;
	char *class_name;

	class_name = make_class_name(dev->class->name, &dev->kobj);
	if (!class_name) {
1080
		error = -ENOMEM;
1081 1082 1083 1084 1085 1086
		goto out;
	}
	if (old_parent) {
		sysfs_remove_link(&dev->kobj, "device");
		sysfs_remove_link(&old_parent->kobj, class_name);
	}
1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098
	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;
1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109
out:
	kfree(class_name);
	return error;
#else
	return 0;
#endif
}

/**
 * device_move - moves a device to a new parent
 * @dev: the pointer to the struct device to be moved
1110
 * @new_parent: the new parent of the device (can by NULL)
1111 1112 1113 1114 1115
 */
int device_move(struct device *dev, struct device *new_parent)
{
	int error;
	struct device *old_parent;
1116
	struct kobject *new_parent_kobj;
1117 1118 1119 1120 1121 1122

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

	new_parent = get_device(new_parent);
1123 1124 1125 1126
	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);
1127 1128 1129
		goto out;
	}
	pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id,
1130 1131
		 new_parent ? new_parent->bus_id : "<NULL>");
	error = kobject_move(&dev->kobj, new_parent_kobj);
1132 1133 1134 1135 1136 1137 1138
	if (error) {
		put_device(new_parent);
		goto out;
	}
	old_parent = dev->parent;
	dev->parent = new_parent;
	if (old_parent)
1139
		klist_remove(&dev->knode_parent);
1140 1141
	if (new_parent)
		klist_add_tail(&dev->knode_parent, &new_parent->klist_children);
1142 1143 1144 1145 1146 1147 1148
	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)) {
1149 1150
			if (new_parent)
				klist_remove(&dev->knode_parent);
1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165
			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);