1
linux/drivers/base/core.c
Kay Sievers 22af74f3b2 Driver core: warn when userspace writes to the uevent file in a non-supported way
In the future we will allow the uevent type to be written to the uevent
file to trigger the different types of uevents.  But for now, as we only
support the ADD event, warn if userspace tries to write anything else to
this file.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-04-27 10:57:31 -07:00

1303 lines
32 KiB
C

/*
* 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
* Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
* Copyright (c) 2006 Novell, Inc.
*
* 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>
#include <linux/kdev_t.h>
#include <linux/notifier.h>
#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.
*/
/**
* 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 :
(dev->class ? dev->class->name : ""));
}
EXPORT_SYMBOL(dev_driver_string);
#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);
ssize_t ret = -EIO;
if (dev_attr->show)
ret = dev_attr->show(dev, dev_attr, buf);
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);
ssize_t ret = -EIO;
if (dev_attr->store)
ret = dev_attr->store(dev, dev_attr, buf, count);
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);
else if (dev->type && dev->type->release)
dev->type->release(dev);
else if (dev->class && dev->class->dev_release)
dev->class->dev_release(dev);
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,
};
static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
{
struct kobj_type *ktype = get_ktype(kobj);
if (ktype == &ktype_device) {
struct device *dev = to_dev(kobj);
if (dev->uevent_suppress)
return 0;
if (dev->bus)
return 1;
if (dev->class)
return 1;
}
return 0;
}
static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
{
struct device *dev = to_dev(kobj);
if (dev->bus)
return dev->bus->name;
if (dev->class)
return dev->class->name;
return NULL;
}
static int dev_uevent(struct kset *kset, struct kobject *kobj, char **envp,
int num_envp, char *buffer, int buffer_size)
{
struct device *dev = to_dev(kobj);
int i = 0;
int length = 0;
int retval = 0;
/* 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));
}
if (dev->type && dev->type->name)
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"DEVTYPE=%s", dev->type->name);
if (dev->driver)
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"DRIVER=%s", dev->driver->name);
#ifdef CONFIG_SYSFS_DEPRECATED
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) {
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"PHYSDEVBUS=%s", dev->bus->name);
if (dev->driver)
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"PHYSDEVDRIVER=%s", dev->driver->name);
}
#endif
/* terminate, set to next free slot, shrink available space */
envp[i] = NULL;
envp = &envp[i];
num_envp -= i;
buffer = &buffer[length];
buffer_size -= length;
if (dev->bus && dev->bus->uevent) {
/* have the bus specific function add its stuff */
retval = dev->bus->uevent(dev, envp, num_envp, buffer, buffer_size);
if (retval)
pr_debug ("%s: bus uevent() returned %d\n",
__FUNCTION__, retval);
}
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);
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);
}
return retval;
}
static struct kset_uevent_ops device_uevent_ops = {
.filter = dev_uevent_filter,
.name = dev_uevent_name,
.uevent = dev_uevent,
};
static ssize_t show_uevent(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct kobject *top_kobj;
struct kset *kset;
char *envp[32];
char data[PAGE_SIZE];
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;
/* 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:
return count;
}
static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
if (memcmp(buf, "add", 3) != 0)
dev_err(dev, "uevent: unsupported action-string; this will "
"be ignored in a future kernel version");
kobject_uevent(&dev->kobj, KOBJ_ADD);
return count;
}
static int device_add_attributes(struct device *dev,
struct device_attribute *attrs)
{
int error = 0;
int i;
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)
{
int error = 0;
int i;
if (groups) {
for (i = 0; groups[i]; i++) {
error = sysfs_create_group(&dev->kobj, groups[i]);
if (error) {
while (--i >= 0)
sysfs_remove_group(&dev->kobj, groups[i]);
break;
}
}
}
return error;
}
static void device_remove_groups(struct device *dev,
struct attribute_group **groups)
{
int i;
if (groups)
for (i = 0; groups[i]; i++)
sysfs_remove_group(&dev->kobj, groups[i]);
}
static int device_add_attrs(struct device *dev)
{
struct class *class = dev->class;
struct device_type *type = dev->type;
int error;
if (class) {
error = device_add_attributes(dev, class->dev_attrs);
if (error)
return error;
}
if (type) {
error = device_add_groups(dev, type->groups);
if (error)
goto err_remove_class_attrs;
}
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);
return error;
}
static void device_remove_attrs(struct device *dev)
{
struct class *class = dev->class;
struct device_type *type = dev->type;
device_remove_groups(dev, dev->groups);
if (type)
device_remove_groups(dev, type->groups);
if (class)
device_remove_attributes(dev, class->dev_attrs);
}
static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
char *buf)
{
return print_dev_t(buf, dev->devt);
}
/*
* devices_subsys - structure to be registered with kobject core.
*/
decl_subsys(devices, &ktype_device, &device_uevent_ops);
/**
* 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);
}
}
/**
* 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);
/**
* device_schedule_callback - helper to schedule a callback for a device
* @dev: device.
* @func: callback function to invoke later.
*
* 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.
*
* Returns 0 if the request was submitted, -ENOMEM if storage could not
* be allocated.
*
* 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.
*/
int device_schedule_callback(struct device *dev,
void (*func)(struct device *))
{
return sysfs_schedule_callback(&dev->kobj,
(void (*)(void *)) func, dev);
}
EXPORT_SYMBOL_GPL(device_schedule_callback);
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);
}
/**
* 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);
klist_init(&dev->klist_children, klist_children_get,
klist_children_put);
INIT_LIST_HEAD(&dev->dma_pools);
INIT_LIST_HEAD(&dev->node);
init_MUTEX(&dev->sem);
spin_lock_init(&dev->devres_lock);
INIT_LIST_HEAD(&dev->devres_head);
device_init_wakeup(dev, 0);
set_dev_node(dev, -1);
}
#ifdef CONFIG_SYSFS_DEPRECATED
static struct kobject * get_device_parent(struct device *dev,
struct device *parent)
{
/* 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)
return &dev->class->subsys.kset.kobj;
else if (parent)
return &parent->kobj;
return NULL;
}
#else
static struct kobject *virtual_device_parent(struct device *dev)
{
static struct kobject *virtual_dir = NULL;
if (!virtual_dir)
virtual_dir = kobject_add_dir(&devices_subsys.kset.kobj, "virtual");
return virtual_dir;
}
static struct kobject * get_device_parent(struct device *dev,
struct device *parent)
{
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)
return &parent->kobj;
return NULL;
}
#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;
return 0;
}
/**
* 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;
char *class_name = NULL;
struct class_interface *class_intf;
int error = -EINVAL;
dev = get_device(dev);
if (!dev || !strlen(dev->bus_id))
goto Error;
pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);
parent = get_device(dev->parent);
error = setup_parent(dev, parent);
if (error)
goto Error;
/* first, register with generic layer. */
kobject_set_name(&dev->kobj, "%s", dev->bus_id);
error = kobject_add(&dev->kobj);
if (error)
goto Error;
/* notify platform of device entry */
if (platform_notify)
platform_notify(dev);
/* notify clients of device entry (new way) */
if (dev->bus)
blocking_notifier_call_chain(&dev->bus->bus_notifier,
BUS_NOTIFY_ADD_DEVICE, dev);
dev->uevent_attr.attr.name = "uevent";
dev->uevent_attr.attr.mode = S_IRUGO | S_IWUSR;
if (dev->driver)
dev->uevent_attr.attr.owner = dev->driver->owner;
dev->uevent_attr.store = store_uevent;
dev->uevent_attr.show = show_uevent;
error = device_create_file(dev, &dev->uevent_attr);
if (error)
goto attrError;
if (MAJOR(dev->devt)) {
struct device_attribute *attr;
attr = kzalloc(sizeof(*attr), GFP_KERNEL);
if (!attr) {
error = -ENOMEM;
goto ueventattrError;
}
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);
goto ueventattrError;
}
dev->devt_attr = attr;
}
if (dev->class) {
sysfs_create_link(&dev->kobj, &dev->class->subsys.kset.kobj,
"subsystem");
/* 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);
if (parent) {
sysfs_create_link(&dev->kobj, &dev->parent->kobj,
"device");
#ifdef CONFIG_SYSFS_DEPRECATED
class_name = make_class_name(dev->class->name,
&dev->kobj);
if (class_name)
sysfs_create_link(&dev->parent->kobj,
&dev->kobj, class_name);
#endif
}
}
if ((error = device_add_attrs(dev)))
goto AttrsError;
if ((error = device_pm_add(dev)))
goto PMError;
if ((error = bus_add_device(dev)))
goto BusError;
kobject_uevent(&dev->kobj, KOBJ_ADD);
bus_attach_device(dev);
if (parent)
klist_add_tail(&dev->knode_parent, &parent->klist_children);
if (dev->class) {
down(&dev->class->sem);
/* tie the class to the device */
list_add_tail(&dev->node, &dev->class->devices);
/* 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);
up(&dev->class->sem);
}
Done:
kfree(class_name);
put_device(dev);
return error;
BusError:
device_pm_remove(dev);
PMError:
if (dev->bus)
blocking_notifier_call_chain(&dev->bus->bus_notifier,
BUS_NOTIFY_DEL_DEVICE, dev);
device_remove_attrs(dev);
AttrsError:
if (dev->devt_attr) {
device_remove_file(dev, dev->devt_attr);
kfree(dev->devt_attr);
}
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);
if (parent) {
#ifdef CONFIG_SYSFS_DEPRECATED
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);
#endif
sysfs_remove_link(&dev->kobj, "device");
}
}
ueventattrError:
device_remove_file(dev, &dev->uevent_attr);
attrError:
kobject_uevent(&dev->kobj, KOBJ_REMOVE);
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;
struct class_interface *class_intf;
if (parent)
klist_del(&dev->knode_parent);
if (dev->devt_attr) {
device_remove_file(dev, dev->devt_attr);
kfree(dev->devt_attr);
}
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);
if (parent) {
#ifdef CONFIG_SYSFS_DEPRECATED
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);
#endif
sysfs_remove_link(&dev->kobj, "device");
}
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);
/* 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);
}
}
device_remove_file(dev, &dev->uevent_attr);
device_remove_attrs(dev);
bus_remove_device(dev);
/*
* 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);
/* Notify the platform of the removal, in case they
* need to do anything...
*/
if (platform_notify_remove)
platform_notify_remove(dev);
if (dev->bus)
blocking_notifier_call_chain(&dev->bus->bus_notifier,
BUS_NOTIFY_DEL_DEVICE, dev);
device_pm_remove(dev);
kobject_uevent(&dev->kobj, KOBJ_REMOVE);
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);
}
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;
}
/**
* device_for_each_child - device child iterator.
* @parent: parent struct device.
* @data: data for the callback.
* @fn: function to be called for each device.
*
* Iterate over @parent's child devices, and call @fn for each,
* 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.
*/
int device_for_each_child(struct device * parent, void * data,
int (*fn)(struct device *, void *))
{
struct klist_iter i;
struct device * child;
int error = 0;
klist_iter_init(&parent->klist_children, &i);
while ((child = next_device(&i)) && !error)
error = fn(child, data);
klist_iter_exit(&i);
return error;
}
/**
* 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;
}
int __init devices_init(void)
{
return subsystem_register(&devices_subsys);
}
EXPORT_SYMBOL_GPL(device_for_each_child);
EXPORT_SYMBOL_GPL(device_find_child);
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);
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
* @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.
*
* A "dev" file will be created, showing the dev_t for the device, if
* the dev_t is not 0,0.
* If a pointer to a parent struct 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
* 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,
dev_t devt, const char *fmt, ...)
{
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()
* @class: pointer to the struct class that this device was registered with
* @devt: the dev_t of the device that was previously registered
*
* This call unregisters and cleans up a device that was created with a
* call to device_create().
*/
void device_destroy(struct class *class, dev_t devt)
{
struct device *dev = 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);
if (dev)
device_unregister(dev);
}
EXPORT_SYMBOL_GPL(device_destroy);
/**
* 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);
#ifdef CONFIG_SYSFS_DEPRECATED
if ((dev->class) && (dev->parent))
old_class_name = make_class_name(dev->class->name, &dev->kobj);
#endif
if (dev->class) {
old_symlink_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL);
if (!old_symlink_name) {
error = -ENOMEM;
goto out_free_old_class;
}
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);
#ifdef CONFIG_SYSFS_DEPRECATED
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);
}
}
#endif
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);
out_free_old_class:
kfree(old_class_name);
return error;
}
EXPORT_SYMBOL_GPL(device_rename);
static int device_move_class_links(struct device *dev,
struct device *old_parent,
struct device *new_parent)
{
int error = 0;
#ifdef CONFIG_SYSFS_DEPRECATED
char *class_name;
class_name = make_class_name(dev->class->name, &dev->kobj);
if (!class_name) {
error = -ENOMEM;
goto out;
}
if (old_parent) {
sysfs_remove_link(&dev->kobj, "device");
sysfs_remove_link(&old_parent->kobj, class_name);
}
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;
out:
kfree(class_name);
return error;
#else
if (old_parent)
sysfs_remove_link(&dev->kobj, "device");
if (new_parent)
error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
"device");
return error;
#endif
}
/**
* device_move - moves a device to a new parent
* @dev: the pointer to the struct device to be moved
* @new_parent: the new parent of the device (can by NULL)
*/
int device_move(struct device *dev, struct device *new_parent)
{
int error;
struct device *old_parent;
struct kobject *new_parent_kobj;
dev = get_device(dev);
if (!dev)
return -EINVAL;
new_parent = get_device(new_parent);
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);
goto out;
}
pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id,
new_parent ? new_parent->bus_id : "<NULL>");
error = kobject_move(&dev->kobj, new_parent_kobj);
if (error) {
put_device(new_parent);
goto out;
}
old_parent = dev->parent;
dev->parent = new_parent;
if (old_parent)
klist_remove(&dev->knode_parent);
if (new_parent)
klist_add_tail(&dev->knode_parent, &new_parent->klist_children);
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)) {
if (new_parent)
klist_remove(&dev->knode_parent);
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);