linux/drivers/base/core.c
Brian Walsh 370226449c drivers/base: Platform notify needs to occur before drivers attach to the device
The platform_notify call for Arm and PPC architectures needs to be called
before the driver attaches to the device.  The problem only presents itself
when hotplugging certain devices while the driver is already loaded.

Signed-off-by: Brian Walsh <brian@walsh.ws>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-25 21:08:39 -07:00

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;
}