/*
* driver.c - centralized device driver management
*
* Copyright (c) 2002-3 Patrick Mochel
* Copyright (c) 2002-3 Open Source Development Labs
*
* This file is released under the GPLv2
*
*/
#include <linux/device.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/string.h>
#include "base.h"
#define to_dev(node) container_of(node, struct device, driver_list)
#define to_drv(obj) container_of(obj, struct device_driver, kobj)
static struct device * next_device(struct klist_iter * i)
{
struct klist_node * n = klist_next(i);
return n ? container_of(n, struct device, knode_driver) : NULL;
}
/**
* driver_for_each_device - Iterator for devices bound to a driver.
* @drv: Driver we're iterating.
* @start: Device to begin with
* @data: Data to pass to the callback.
* @fn: Function to call for each device.
*
* Iterate over the @drv's list of devices calling @fn for each one.
*/
int driver_for_each_device(struct device_driver * drv, struct device * start,
void * data, int (*fn)(struct device *, void *))
{
struct klist_iter i;
struct device * dev;
int error = 0;
if (!drv)
return -EINVAL;
klist_iter_init_node(&drv->klist_devices, &i,
start ? &start->knode_driver : NULL);
while ((dev = next_device(&i)) && !error)
error = fn(dev, data);
klist_iter_exit(&i);
return error;
}
EXPORT_SYMBOL_GPL(driver_for_each_device);
/**
* driver_find_device - device iterator for locating a particular device.
* @drv: The device's driver
* @start: Device to begin with
* @data: Data to pass to match function
* @match: Callback function to check device
*
* This is similar to the driver_for_each_device() 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, this function will
* return to the caller and not iterate over any more devices.
*/
struct device * driver_find_device(struct device_driver *drv,
struct device * start, void * data,
int (*match)(struct device *, void *))
{
struct klist_iter i;
struct device *dev;
if (!drv)
return NULL;
klist_iter_init_node(&drv->klist_devices, &i,
(start ? &start->knode_driver : NULL));
while ((dev = next_device(&i)))
if (match(dev, data) && get_device(dev))
break;
klist_iter_exit(&i);
return dev;
}
EXPORT_SYMBOL_GPL(driver_find_device);
/**
* driver_create_file - create sysfs file for driver.
* @drv: driver.
* @attr: driver attribute descriptor.
*/
int driver_create_file(struct device_driver * drv, struct driver_attribute * attr)
{
int error;
if (get_driver(drv)) {
error = sysfs_create_file(&drv->kobj, &attr->attr);
put_driver(drv);
} else
error = -EINVAL;
return error;
}
/**
* driver_remove_file - remove sysfs file for driver.
* @drv: driver.
* @attr: driver attribute descriptor.
*/
void driver_remove_file(struct device_driver * drv, struct driver_attribute * attr)
{
if (get_driver(drv)) {
sysfs_remove_file(&drv->kobj, &attr->attr);
put_driver(drv);
}
}
/**
* get_driver - increment driver reference count.
* @drv: driver.
*/
struct device_driver * get_driver(struct device_driver * drv)
{
return drv ? to_drv(kobject_get(&drv->kobj)) : NULL;
}
/**
* put_driver - decrement driver's refcount.
* @drv: driver.
*/
void put_driver(struct device_driver * drv)
{
kobject_put(&drv->kobj);
}
/**
* driver_register - register driver with bus
* @drv: driver to register
*
* We pass off most of the work to the bus_add_driver() call,
* since most of the things we have to do deal with the bus
* structures.
*
* The one interesting aspect is that we setup @drv->unloaded
* as a completion that gets complete when the driver reference
* count reaches 0.
*/
int driver_register(struct device_driver * drv)
{
if ((drv->bus->probe && drv->probe) ||
(drv->bus->remove && drv->remove) ||
(drv->bus->shutdown && drv->shutdown)) {
printk(KERN_WARNING "Driver '%s' needs updating - please use bus_type methods\n", drv->name);
}
klist_init(&drv->klist_devices, NULL, NULL);
init_completion(&drv->unloaded);
return bus_add_driver(drv);
}
/**
* driver_unregister - remove driver from system.
* @drv: driver.
*
* Again, we pass off most of the work to the bus-level call.
*
* Though, once that is done, we wait until @drv->unloaded is completed.
* This will block until the driver refcount reaches 0, and it is
* released. Only modular drivers will call this function, and we
* have to guarantee that it won't complete, letting the driver
* unload until all references are gone.
*/
void driver_unregister(struct device_driver * drv)
{
bus_remove_driver(drv);
/*
* If the driver is a module, we are probably in
* the module unload path, and we want to wait
* for everything to unload before we can actually
* finish the unload.
*/
if (drv->owner)
wait_for_completion(&drv->unloaded);
}
/**
* driver_find - locate driver on a bus by its name.
* @name: name of the driver.
* @bus: bus to scan for the driver.
*
* Call kset_find_obj() to iterate over list of drivers on
* a bus to find driver by name. Return driver if found.
*
* Note that kset_find_obj increments driver's reference count.
*/
struct device_driver *driver_find(const char *name, struct bus_type *bus)
{
struct kobject *k = kset_find_obj(&bus->drivers, name);
if (k)
return to_drv(k);
return NULL;
}
EXPORT_SYMBOL_GPL(driver_register);
EXPORT_SYMBOL_GPL(driver_unregister);
EXPORT_SYMBOL_GPL(get_driver);
EXPORT_SYMBOL_GPL(put_driver);
EXPORT_SYMBOL_GPL(driver_find);
EXPORT_SYMBOL_GPL(driver_create_file);
EXPORT_SYMBOL_GPL(driver_remove_file);
