linux/drivers/base/sys.c
Kay Sievers ca22e56deb driver-core: implement 'sysdev' functionality for regular devices and buses
All sysdev classes and sysdev devices will converted to regular devices
and buses to properly hook userspace into the event processing.

There is no interesting difference between a 'sysdev' and 'device' which
would justify to roll an entire own subsystem with different userspace
export semantics. Userspace relies on events and generic sysfs subsystem
infrastructure from sysdev devices, which are currently not properly
available.

Every converted sysdev class will create a regular device with the class
name in /sys/devices/system and all registered devices will becom a children
of theses devices.

For compatibility reasons, the sysdev class-wide attributes are created
at this parent device. (Do not copy that logic for anything new, subsystem-
wide properties belong to the subsystem, not to some fake parent device
created in /sys/devices.)

Every sysdev driver is implemented as a simple subsystem interface now,
and no longer called a driver.

After all sysdev classes are ported to regular driver core entities, the
sysdev implementation will be entirely removed from the kernel.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-14 14:29:38 -08:00

384 lines
9.7 KiB
C

/*
* sys.c - pseudo-bus for system 'devices' (cpus, PICs, timers, etc)
*
* Copyright (c) 2002-3 Patrick Mochel
* 2002-3 Open Source Development Lab
*
* This file is released under the GPLv2
*
* This exports a 'system' bus type.
* By default, a 'sys' bus gets added to the root of the system. There will
* always be core system devices. Devices can use sysdev_register() to
* add themselves as children of the system bus.
*/
#include <linux/sysdev.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/pm.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/interrupt.h>
#include "base.h"
#define to_sysdev(k) container_of(k, struct sys_device, kobj)
#define to_sysdev_attr(a) container_of(a, struct sysdev_attribute, attr)
static ssize_t
sysdev_show(struct kobject *kobj, struct attribute *attr, char *buffer)
{
struct sys_device *sysdev = to_sysdev(kobj);
struct sysdev_attribute *sysdev_attr = to_sysdev_attr(attr);
if (sysdev_attr->show)
return sysdev_attr->show(sysdev, sysdev_attr, buffer);
return -EIO;
}
static ssize_t
sysdev_store(struct kobject *kobj, struct attribute *attr,
const char *buffer, size_t count)
{
struct sys_device *sysdev = to_sysdev(kobj);
struct sysdev_attribute *sysdev_attr = to_sysdev_attr(attr);
if (sysdev_attr->store)
return sysdev_attr->store(sysdev, sysdev_attr, buffer, count);
return -EIO;
}
static const struct sysfs_ops sysfs_ops = {
.show = sysdev_show,
.store = sysdev_store,
};
static struct kobj_type ktype_sysdev = {
.sysfs_ops = &sysfs_ops,
};
int sysdev_create_file(struct sys_device *s, struct sysdev_attribute *a)
{
return sysfs_create_file(&s->kobj, &a->attr);
}
void sysdev_remove_file(struct sys_device *s, struct sysdev_attribute *a)
{
sysfs_remove_file(&s->kobj, &a->attr);
}
EXPORT_SYMBOL_GPL(sysdev_create_file);
EXPORT_SYMBOL_GPL(sysdev_remove_file);
#define to_sysdev_class(k) container_of(k, struct sysdev_class, kset.kobj)
#define to_sysdev_class_attr(a) container_of(a, \
struct sysdev_class_attribute, attr)
static ssize_t sysdev_class_show(struct kobject *kobj, struct attribute *attr,
char *buffer)
{
struct sysdev_class *class = to_sysdev_class(kobj);
struct sysdev_class_attribute *class_attr = to_sysdev_class_attr(attr);
if (class_attr->show)
return class_attr->show(class, class_attr, buffer);
return -EIO;
}
static ssize_t sysdev_class_store(struct kobject *kobj, struct attribute *attr,
const char *buffer, size_t count)
{
struct sysdev_class *class = to_sysdev_class(kobj);
struct sysdev_class_attribute *class_attr = to_sysdev_class_attr(attr);
if (class_attr->store)
return class_attr->store(class, class_attr, buffer, count);
return -EIO;
}
static const struct sysfs_ops sysfs_class_ops = {
.show = sysdev_class_show,
.store = sysdev_class_store,
};
static struct kobj_type ktype_sysdev_class = {
.sysfs_ops = &sysfs_class_ops,
};
int sysdev_class_create_file(struct sysdev_class *c,
struct sysdev_class_attribute *a)
{
return sysfs_create_file(&c->kset.kobj, &a->attr);
}
EXPORT_SYMBOL_GPL(sysdev_class_create_file);
void sysdev_class_remove_file(struct sysdev_class *c,
struct sysdev_class_attribute *a)
{
sysfs_remove_file(&c->kset.kobj, &a->attr);
}
EXPORT_SYMBOL_GPL(sysdev_class_remove_file);
extern struct kset *system_kset;
int sysdev_class_register(struct sysdev_class *cls)
{
int retval;
pr_debug("Registering sysdev class '%s'\n", cls->name);
INIT_LIST_HEAD(&cls->drivers);
memset(&cls->kset.kobj, 0x00, sizeof(struct kobject));
cls->kset.kobj.parent = &system_kset->kobj;
cls->kset.kobj.ktype = &ktype_sysdev_class;
cls->kset.kobj.kset = system_kset;
retval = kobject_set_name(&cls->kset.kobj, "%s", cls->name);
if (retval)
return retval;
retval = kset_register(&cls->kset);
if (!retval && cls->attrs)
retval = sysfs_create_files(&cls->kset.kobj,
(const struct attribute **)cls->attrs);
return retval;
}
void sysdev_class_unregister(struct sysdev_class *cls)
{
pr_debug("Unregistering sysdev class '%s'\n",
kobject_name(&cls->kset.kobj));
if (cls->attrs)
sysfs_remove_files(&cls->kset.kobj,
(const struct attribute **)cls->attrs);
kset_unregister(&cls->kset);
}
EXPORT_SYMBOL_GPL(sysdev_class_register);
EXPORT_SYMBOL_GPL(sysdev_class_unregister);
static DEFINE_MUTEX(sysdev_drivers_lock);
/*
* @dev != NULL means that we're unwinding because some drv->add()
* failed for some reason. You need to grab sysdev_drivers_lock before
* calling this.
*/
static void __sysdev_driver_remove(struct sysdev_class *cls,
struct sysdev_driver *drv,
struct sys_device *from_dev)
{
struct sys_device *dev = from_dev;
list_del_init(&drv->entry);
if (!cls)
return;
if (!drv->remove)
goto kset_put;
if (dev)
list_for_each_entry_continue_reverse(dev, &cls->kset.list,
kobj.entry)
drv->remove(dev);
else
list_for_each_entry(dev, &cls->kset.list, kobj.entry)
drv->remove(dev);
kset_put:
kset_put(&cls->kset);
}
/**
* sysdev_driver_register - Register auxiliary driver
* @cls: Device class driver belongs to.
* @drv: Driver.
*
* @drv is inserted into @cls->drivers to be
* called on each operation on devices of that class. The refcount
* of @cls is incremented.
*/
int sysdev_driver_register(struct sysdev_class *cls, struct sysdev_driver *drv)
{
struct sys_device *dev = NULL;
int err = 0;
if (!cls) {
WARN(1, KERN_WARNING "sysdev: invalid class passed to %s!\n",
__func__);
return -EINVAL;
}
/* Check whether this driver has already been added to a class. */
if (drv->entry.next && !list_empty(&drv->entry))
WARN(1, KERN_WARNING "sysdev: class %s: driver (%p) has already"
" been registered to a class, something is wrong, but "
"will forge on!\n", cls->name, drv);
mutex_lock(&sysdev_drivers_lock);
if (cls && kset_get(&cls->kset)) {
list_add_tail(&drv->entry, &cls->drivers);
/* If devices of this class already exist, tell the driver */
if (drv->add) {
list_for_each_entry(dev, &cls->kset.list, kobj.entry) {
err = drv->add(dev);
if (err)
goto unwind;
}
}
} else {
err = -EINVAL;
WARN(1, KERN_ERR "%s: invalid device class\n", __func__);
}
goto unlock;
unwind:
__sysdev_driver_remove(cls, drv, dev);
unlock:
mutex_unlock(&sysdev_drivers_lock);
return err;
}
/**
* sysdev_driver_unregister - Remove an auxiliary driver.
* @cls: Class driver belongs to.
* @drv: Driver.
*/
void sysdev_driver_unregister(struct sysdev_class *cls,
struct sysdev_driver *drv)
{
mutex_lock(&sysdev_drivers_lock);
__sysdev_driver_remove(cls, drv, NULL);
mutex_unlock(&sysdev_drivers_lock);
}
EXPORT_SYMBOL_GPL(sysdev_driver_register);
EXPORT_SYMBOL_GPL(sysdev_driver_unregister);
/**
* sysdev_register - add a system device to the tree
* @sysdev: device in question
*
*/
int sysdev_register(struct sys_device *sysdev)
{
int error;
struct sysdev_class *cls = sysdev->cls;
if (!cls)
return -EINVAL;
pr_debug("Registering sys device of class '%s'\n",
kobject_name(&cls->kset.kobj));
/* initialize the kobject to 0, in case it had previously been used */
memset(&sysdev->kobj, 0x00, sizeof(struct kobject));
/* Make sure the kset is set */
sysdev->kobj.kset = &cls->kset;
/* Register the object */
error = kobject_init_and_add(&sysdev->kobj, &ktype_sysdev, NULL,
"%s%d", kobject_name(&cls->kset.kobj),
sysdev->id);
if (!error) {
struct sysdev_driver *drv;
pr_debug("Registering sys device '%s'\n",
kobject_name(&sysdev->kobj));
mutex_lock(&sysdev_drivers_lock);
/* Generic notification is implicit, because it's that
* code that should have called us.
*/
/* Notify class auxiliary drivers */
list_for_each_entry(drv, &cls->drivers, entry) {
if (drv->add)
drv->add(sysdev);
}
mutex_unlock(&sysdev_drivers_lock);
kobject_uevent(&sysdev->kobj, KOBJ_ADD);
}
return error;
}
void sysdev_unregister(struct sys_device *sysdev)
{
struct sysdev_driver *drv;
mutex_lock(&sysdev_drivers_lock);
list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
if (drv->remove)
drv->remove(sysdev);
}
mutex_unlock(&sysdev_drivers_lock);
kobject_put(&sysdev->kobj);
}
EXPORT_SYMBOL_GPL(sysdev_register);
EXPORT_SYMBOL_GPL(sysdev_unregister);
#define to_ext_attr(x) container_of(x, struct sysdev_ext_attribute, attr)
ssize_t sysdev_store_ulong(struct sys_device *sysdev,
struct sysdev_attribute *attr,
const char *buf, size_t size)
{
struct sysdev_ext_attribute *ea = to_ext_attr(attr);
char *end;
unsigned long new = simple_strtoul(buf, &end, 0);
if (end == buf)
return -EINVAL;
*(unsigned long *)(ea->var) = new;
/* Always return full write size even if we didn't consume all */
return size;
}
EXPORT_SYMBOL_GPL(sysdev_store_ulong);
ssize_t sysdev_show_ulong(struct sys_device *sysdev,
struct sysdev_attribute *attr,
char *buf)
{
struct sysdev_ext_attribute *ea = to_ext_attr(attr);
return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
}
EXPORT_SYMBOL_GPL(sysdev_show_ulong);
ssize_t sysdev_store_int(struct sys_device *sysdev,
struct sysdev_attribute *attr,
const char *buf, size_t size)
{
struct sysdev_ext_attribute *ea = to_ext_attr(attr);
char *end;
long new = simple_strtol(buf, &end, 0);
if (end == buf || new > INT_MAX || new < INT_MIN)
return -EINVAL;
*(int *)(ea->var) = new;
/* Always return full write size even if we didn't consume all */
return size;
}
EXPORT_SYMBOL_GPL(sysdev_store_int);
ssize_t sysdev_show_int(struct sys_device *sysdev,
struct sysdev_attribute *attr,
char *buf)
{
struct sysdev_ext_attribute *ea = to_ext_attr(attr);
return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
}
EXPORT_SYMBOL_GPL(sysdev_show_int);