linux/drivers/base/core.c

839 lines
20 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 <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 : "");
}
EXPORT_SYMBOL_GPL(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->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->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));
}
/* add bus name (same as SUBSYSTEM, deprecated) */
if (dev->bus)
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"PHYSDEVBUS=%s", dev->bus->name);
/* add driver name (PHYSDEV* values are deprecated)*/
if (dev->driver) {
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"DRIVER=%s", dev->driver->name);
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"PHYSDEVDRIVER=%s", dev->driver->name);
}
/* 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 - 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 - dev_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 store_uevent(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
kobject_uevent(&dev->kobj, KOBJ_ADD);
return count;
}
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]);
}
}
}
static int device_add_attrs(struct device *dev)
{
struct class *class = dev->class;
int error = 0;
int i;
if (!class)
return 0;
if (class->dev_attrs) {
for (i = 0; attr_name(class->dev_attrs[i]); i++) {
error = device_create_file(dev, &class->dev_attrs[i]);
if (error)
break;
}
}
if (error)
while (--i >= 0)
device_remove_file(dev, &class->dev_attrs[i]);
return error;
}
static void device_remove_attrs(struct device *dev)
{
struct class *class = dev->class;
int i;
if (!class)
return;
if (class->dev_attrs) {
for (i = 0; attr_name(class->dev_attrs[i]); i++)
device_remove_file(dev, &class->dev_attrs[i]);
}
}
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);
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);
device_init_wakeup(dev, 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;
/* if this is a class device, and has no parent, create one */
if ((dev->class) && (dev->parent == NULL)) {
error = virtual_device_parent(dev);
if (error)
goto Error;
}
parent = get_device(dev->parent);
pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);
/* first, register with generic layer. */
kobject_set_name(&dev->kobj, "%s", dev->bus_id);
if (parent)
dev->kobj.parent = &parent->kobj;
if ((error = kobject_add(&dev->kobj)))
goto Error;
/* notify platform of device entry */
if (platform_notify)
platform_notify(dev);
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;
device_create_file(dev, &dev->uevent_attr);
if (MAJOR(dev->devt)) {
struct device_attribute *attr;
attr = kzalloc(sizeof(*attr), GFP_KERNEL);
if (!attr) {
error = -ENOMEM;
goto PMError;
}
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 attrError;
}
dev->devt_attr = attr;
}
if (dev->class) {
sysfs_create_link(&dev->kobj, &dev->class->subsys.kset.kobj,
"subsystem");
sysfs_create_link(&dev->class->subsys.kset.kobj, &dev->kobj,
dev->bus_id);
if (parent) {
sysfs_create_link(&dev->kobj, &dev->parent->kobj, "device");
class_name = make_class_name(dev->class->name, &dev->kobj);
sysfs_create_link(&dev->parent->kobj, &dev->kobj, class_name);
}
}
if ((error = device_add_attrs(dev)))
goto AttrsError;
if ((error = device_add_groups(dev)))
goto GroupError;
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:
device_remove_groups(dev);
GroupError:
device_remove_attrs(dev);
AttrsError:
if (dev->devt_attr) {
device_remove_file(dev, dev->devt_attr);
kfree(dev->devt_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;
char *class_name = NULL;
struct class_interface *class_intf;
if (parent)
klist_del(&dev->knode_parent);
if (dev->devt_attr)
device_remove_file(dev, dev->devt_attr);
if (dev->class) {
sysfs_remove_link(&dev->kobj, "subsystem");
sysfs_remove_link(&dev->class->subsys.kset.kobj, dev->bus_id);
class_name = make_class_name(dev->class->name, &dev->kobj);
if (parent) {
sysfs_remove_link(&dev->kobj, "device");
sysfs_remove_link(&dev->parent->kobj, class_name);
}
kfree(class_name);
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);
}
device_remove_file(dev, &dev->uevent_attr);
device_remove_groups(dev);
device_remove_attrs(dev);
/* Notify the platform of the removal, in case they
* need to do anything...
*/
if (platform_notify_remove)
platform_notify_remove(dev);
bus_remove_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;
}
int __init devices_init(void)
{
return subsystem_register(&devices_subsys);
}
EXPORT_SYMBOL_GPL(device_for_each_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);
if ((dev->class) && (dev->parent))
old_class_name = make_class_name(dev->class->name, &dev->kobj);
if (dev->class) {
old_symlink_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL);
if (!old_symlink_name)
return -ENOMEM;
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);
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);
}
}
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(old_class_name);
kfree(new_class_name);
kfree(old_symlink_name);
return error;
}