core.c 32.8 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, 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->type && dev->type->name)
		add_uevent_var(envp, num_envp, &i,
			       buffer, buffer_size, &length,
			       "DEVTYPE=%s", dev->type->name);

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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);
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			if (path) {
				add_uevent_var(envp, num_envp, &i,
					       buffer, buffer_size, &length,
					       "PHYSDEVPATH=%s", path);
				kfree(path);
			}
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			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 show_uevent(struct device *dev, struct device_attribute *attr,
			   char *buf)
{
	struct kobject *top_kobj;
	struct kset *kset;
	char *envp[32];
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	char *data = NULL;
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	char *pos;
	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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	data = (char *)get_zeroed_page(GFP_KERNEL);
	if (!data)
		return -ENOMEM;

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

	/* copy keys to file */
	for (i = 0; envp[i]; i++) {
		pos = &buf[count];
		count += sprintf(pos, "%s\n", envp[i]);
	}
out:
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	free_page((unsigned long)data);
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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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	if (memcmp(buf, "add", 3) != 0)
		dev_err(dev, "uevent: unsupported action-string; this will "
			"be ignored in a future kernel version");
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	kobject_uevent(&dev->kobj, KOBJ_ADD);
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	return count;
}

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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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/*
 *	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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{
	/* 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.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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	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)
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{
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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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/**
 *	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;
674

675 676 677 678
	/* notify platform of device entry */
	if (platform_notify)
		platform_notify(dev);

679 680 681 682 683
	/* notify clients of device entry (new way) */
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->bus_notifier,
					     BUS_NOTIFY_ADD_DEVICE, dev);

684
	dev->uevent_attr.attr.name = "uevent";
685
	dev->uevent_attr.attr.mode = S_IRUGO | S_IWUSR;
686 687 688
	if (dev->driver)
		dev->uevent_attr.attr.owner = dev->driver->owner;
	dev->uevent_attr.store = store_uevent;
689
	dev->uevent_attr.show = show_uevent;
690 691 692
	error = device_create_file(dev, &dev->uevent_attr);
	if (error)
		goto attrError;
693

694 695 696 697 698
	if (MAJOR(dev->devt)) {
		struct device_attribute *attr;
		attr = kzalloc(sizeof(*attr), GFP_KERNEL);
		if (!attr) {
			error = -ENOMEM;
699
			goto ueventattrError;
700 701 702 703 704 705 706 707 708
		}
		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);
709
			goto ueventattrError;
710 711 712 713 714
		}

		dev->devt_attr = attr;
	}

715
	if (dev->class) {
716
		sysfs_create_link(&dev->kobj, &dev->class->subsys.kobj,
717
				  "subsystem");
718 719
		/* If this is not a "fake" compatible device, then create the
		 * symlink from the class to the device. */
720 721
		if (dev->kobj.parent != &dev->class->subsys.kobj)
			sysfs_create_link(&dev->class->subsys.kobj,
722
					  &dev->kobj, dev->bus_id);
723
		if (parent) {
724 725
			sysfs_create_link(&dev->kobj, &dev->parent->kobj,
							"device");
726
#ifdef CONFIG_SYSFS_DEPRECATED
727 728 729 730 731
			class_name = make_class_name(dev->class->name,
							&dev->kobj);
			if (class_name)
				sysfs_create_link(&dev->parent->kobj,
						  &dev->kobj, class_name);
732
#endif
733
		}
734
	}
735

736 737
	if ((error = device_add_attrs(dev)))
		goto AttrsError;
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	if ((error = device_pm_add(dev)))
		goto PMError;
	if ((error = bus_add_device(dev)))
		goto BusError;
742
	kobject_uevent(&dev->kobj, KOBJ_ADD);
743
	bus_attach_device(dev);
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	if (parent)
745
		klist_add_tail(&dev->knode_parent, &parent->klist_children);
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747 748
	if (dev->class) {
		down(&dev->class->sem);
749
		/* tie the class to the device */
750
		list_add_tail(&dev->node, &dev->class->devices);
751 752 753 754 755

		/* 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);
756 757
		up(&dev->class->sem);
	}
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758
 Done:
759
	kfree(class_name);
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	put_device(dev);
	return error;
 BusError:
	device_pm_remove(dev);
 PMError:
765 766 767
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->bus_notifier,
					     BUS_NOTIFY_DEL_DEVICE, dev);
768
	device_remove_attrs(dev);
769
 AttrsError:
770 771 772 773
	if (dev->devt_attr) {
		device_remove_file(dev, dev->devt_attr);
		kfree(dev->devt_attr);
	}
774 775 776 777 778

	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. */
779 780
		if (dev->kobj.parent != &dev->class->subsys.kobj)
			sysfs_remove_link(&dev->class->subsys.kobj,
781 782
					  dev->bus_id);
		if (parent) {
783
#ifdef CONFIG_SYSFS_DEPRECATED
784 785 786 787 788 789
			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);
790
#endif
791 792 793
			sysfs_remove_link(&dev->kobj, "device");
		}
	}
794 795
 ueventattrError:
	device_remove_file(dev, &dev->uevent_attr);
796
 attrError:
797
	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;
868
	struct class_interface *class_intf;
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	if (parent)
871
		klist_del(&dev->knode_parent);
872
	if (dev->devt_attr) {
873
		device_remove_file(dev, dev->devt_attr);
874 875
		kfree(dev->devt_attr);
	}
876 877
	if (dev->class) {
		sysfs_remove_link(&dev->kobj, "subsystem");
878 879
		/* If this is not a "fake" compatible device, remove the
		 * symlink from the class to the device. */
880 881
		if (dev->kobj.parent != &dev->class->subsys.kobj)
			sysfs_remove_link(&dev->class->subsys.kobj,
882
					  dev->bus_id);
883
		if (parent) {
884
#ifdef CONFIG_SYSFS_DEPRECATED
885 886
			char *class_name = make_class_name(dev->class->name,
							   &dev->kobj);
887 888 889
			if (class_name)
				sysfs_remove_link(&dev->parent->kobj,
						  class_name);
890
			kfree(class_name);
891
#endif
892
			sysfs_remove_link(&dev->kobj, "device");
893
		}
894

895
		down(&dev->class->sem);
896 897 898 899 900
		/* 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 */
901 902
		list_del_init(&dev->node);
		up(&dev->class->sem);
903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927

		/* 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);
		}
928
	}
929
	device_remove_file(dev, &dev->uevent_attr);
930
	device_remove_attrs(dev);
931
	bus_remove_device(dev);
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933 934 935 936 937 938 939
	/*
	 * 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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940 941 942 943 944
	/* Notify the platform of the removal, in case they
	 * need to do anything...
	 */
	if (platform_notify_remove)
		platform_notify_remove(dev);
945 946 947
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->bus_notifier,
					     BUS_NOTIFY_DEL_DEVICE, dev);
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948
	device_pm_remove(dev);
949
	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
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950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973
	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);
}


974 975 976 977 978 979
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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980 981
/**
 *	device_for_each_child - device child iterator.
982
 *	@parent: parent struct device.
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983 984 985
 *	@data:	data for the callback.
 *	@fn:	function to be called for each device.
 *
986
 *	Iterate over @parent's child devices, and call @fn for each,
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987 988 989 990 991
 *	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.
 */
992
int device_for_each_child(struct device * parent, void * data,
L
Linus Torvalds 已提交
993 994
		     int (*fn)(struct device *, void *))
{
995
	struct klist_iter i;
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Linus Torvalds 已提交
996 997 998
	struct device * child;
	int error = 0;

999 1000 1001 1002
	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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1003 1004 1005
	return error;
}

1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037
/**
 * 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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1038 1039 1040 1041 1042 1043
int __init devices_init(void)
{
	return subsystem_register(&devices_subsys);
}

EXPORT_SYMBOL_GPL(device_for_each_child);
1044
EXPORT_SYMBOL_GPL(device_find_child);
L
Linus Torvalds 已提交
1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056

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);
1057 1058 1059 1060 1061 1062 1063 1064 1065 1066


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
1067 1068 1069 1070 1071 1072 1073
 * @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.
1074 1075 1076
 *
 * A "dev" file will be created, showing the dev_t for the device, if
 * the dev_t is not 0,0.
1077 1078 1079 1080
 * 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
1081 1082 1083 1084 1085 1086
 * 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,
1087
			     dev_t devt, const char *fmt, ...)
1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123
{
	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()
1124 1125
 * @class: pointer to the struct class that this device was registered with
 * @devt: the dev_t of the device that was previously registered
1126
 *
1127 1128
 * This call unregisters and cleans up a device that was created with a
 * call to device_create().
1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143
 */
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);

1144
	if (dev)
1145 1146 1147
		device_unregister(dev);
}
EXPORT_SYMBOL_GPL(device_destroy);
1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166

/**
 * 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);

1167
#ifdef CONFIG_SYSFS_DEPRECATED
1168 1169
	if ((dev->class) && (dev->parent))
		old_class_name = make_class_name(dev->class->name, &dev->kobj);
1170
#endif
1171 1172 1173

	if (dev->class) {
		old_symlink_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL);
1174 1175 1176 1177
		if (!old_symlink_name) {
			error = -ENOMEM;
			goto out_free_old_class;
		}
1178 1179 1180 1181 1182 1183 1184
		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);

1185
#ifdef CONFIG_SYSFS_DEPRECATED
1186 1187 1188 1189 1190 1191 1192 1193
	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);
		}
	}
1194 1195
#endif

1196
	if (dev->class) {
1197
		sysfs_remove_link(&dev->class->subsys.kobj,
1198
				  old_symlink_name);
1199
		sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
1200 1201 1202 1203 1204 1205
				  dev->bus_id);
	}
	put_device(dev);

	kfree(new_class_name);
	kfree(old_symlink_name);
1206 1207
 out_free_old_class:
	kfree(old_class_name);
1208 1209 1210

	return error;
}
1211
EXPORT_SYMBOL_GPL(device_rename);
1212 1213 1214 1215 1216

static int device_move_class_links(struct device *dev,
				   struct device *old_parent,
				   struct device *new_parent)
{
1217
	int error = 0;
1218 1219 1220 1221 1222
#ifdef CONFIG_SYSFS_DEPRECATED
	char *class_name;

	class_name = make_class_name(dev->class->name, &dev->kobj);
	if (!class_name) {
1223
		error = -ENOMEM;
1224 1225 1226 1227 1228 1229
		goto out;
	}
	if (old_parent) {
		sysfs_remove_link(&dev->kobj, "device");
		sysfs_remove_link(&old_parent->kobj, class_name);
	}
1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241
	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;
1242 1243 1244 1245
out:
	kfree(class_name);
	return error;
#else
1246 1247 1248 1249 1250 1251
	if (old_parent)
		sysfs_remove_link(&dev->kobj, "device");
	if (new_parent)
		error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
					  "device");
	return error;
1252 1253 1254 1255 1256 1257
#endif
}

/**
 * device_move - moves a device to a new parent
 * @dev: the pointer to the struct device to be moved
1258
 * @new_parent: the new parent of the device (can by NULL)
1259 1260 1261 1262 1263
 */
int device_move(struct device *dev, struct device *new_parent)
{
	int error;
	struct device *old_parent;
1264
	struct kobject *new_parent_kobj;
1265 1266 1267 1268 1269 1270

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

	new_parent = get_device(new_parent);
1271 1272 1273 1274
	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);
1275 1276 1277
		goto out;
	}
	pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id,
1278 1279
		 new_parent ? new_parent->bus_id : "<NULL>");
	error = kobject_move(&dev->kobj, new_parent_kobj);
1280 1281 1282 1283 1284 1285 1286
	if (error) {
		put_device(new_parent);
		goto out;
	}
	old_parent = dev->parent;
	dev->parent = new_parent;
	if (old_parent)
1287
		klist_remove(&dev->knode_parent);
1288 1289
	if (new_parent)
		klist_add_tail(&dev->knode_parent, &new_parent->klist_children);
1290 1291 1292 1293 1294 1295 1296
	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)) {
1297 1298
			if (new_parent)
				klist_remove(&dev->knode_parent);
1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313
			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);