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/*
* drivers/base/dd.c - The core device/driver interactions.
*
* This file contains the (sometimes tricky) code that controls the
* interactions between devices and drivers, which primarily includes
* driver binding and unbinding.
*
* All of this code used to exist in drivers/base/bus.c, but was
* relocated to here in the name of compartmentalization (since it wasn't
* strictly code just for the 'struct bus_type'.
*
* Copyright (c) 2002-5 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 "base.h"
#include "power/power.h"
#define to_drv(node) container_of(node, struct device_driver, kobj.entry)
/**
* device_bind_driver - bind a driver to one device.
* @dev: device.
*
* Allow manual attachment of a driver to a device.
* Caller must have already set @dev->driver.
*
* Note that this does not modify the bus reference count
* nor take the bus's rwsem. Please verify those are accounted
* for before calling this. (It is ok to call with no other effort
* from a driver's probe() method.)
*/
void device_bind_driver(struct device * dev)
{
pr_debug("bound device '%s' to driver '%s'\n",
dev->bus_id, dev->driver->name);
klist_add_tail(&dev->driver->klist_devices, &dev->knode_driver);
sysfs_create_link(&dev->driver->kobj, &dev->kobj,
kobject_name(&dev->kobj));
sysfs_create_link(&dev->kobj, &dev->driver->kobj, "driver");
}
/**
* driver_probe_device - attempt to bind device & driver.
* @drv: driver.
* @dev: device.
*
* First, we call the bus's match function, if one present, which
* should compare the device IDs the driver supports with the
* device IDs of the device. Note we don't do this ourselves
* because we don't know the format of the ID structures, nor what
* is to be considered a match and what is not.
*
* If we find a match, we call @drv->probe(@dev) if it exists, and
* call device_bind_driver() above.
*/
int driver_probe_device(struct device_driver * drv, struct device * dev)
{
int error = 0;
if (drv->bus->match && !drv->bus->match(dev, drv))
return -ENODEV;
down(&dev->sem);
dev->driver = drv;
if (drv->probe) {
error = drv->probe(dev);
if (error) {
dev->driver = NULL;
up(&dev->sem);
return error;
}
}
up(&dev->sem);
device_bind_driver(dev);
return 0;
}
/**
* device_attach - try to attach device to a driver.
* @dev: device.
*
* Walk the list of drivers that the bus has and call
* driver_probe_device() for each pair. If a compatible
* pair is found, break out and return.
*/
int device_attach(struct device * dev)
{
struct bus_type * bus = dev->bus;
struct list_head * entry;
int error;
if (dev->driver) {
device_bind_driver(dev);
return 1;
}
if (bus->match) {
list_for_each(entry, &bus->drivers.list) {
struct device_driver * drv = to_drv(entry);
error = driver_probe_device(drv, dev);
if (!error)
/* success, driver matched */
return 1;
if (error != -ENODEV && error != -ENXIO)
/* driver matched but the probe failed */
printk(KERN_WARNING
"%s: probe of %s failed with error %d\n",
drv->name, dev->bus_id, error);
}
}
return 0;
}
/**
* driver_attach - try to bind driver to devices.
* @drv: driver.
*
* Walk the list of devices that the bus has on it and try to
* match the driver with each one. If driver_probe_device()
* returns 0 and the @dev->driver is set, we've found a
* compatible pair.
*
* Note that we ignore the -ENODEV error from driver_probe_device(),
* since it's perfectly valid for a driver not to bind to any devices.
*/
void driver_attach(struct device_driver * drv)
{
struct bus_type * bus = drv->bus;
struct list_head * entry;
int error;
if (!bus->match)
return;
list_for_each(entry, &bus->devices.list) {
struct device * dev = container_of(entry, struct device, bus_list);
if (!dev->driver) {
error = driver_probe_device(drv, dev);
if (error && (error != -ENODEV))
/* driver matched but the probe failed */
printk(KERN_WARNING
"%s: probe of %s failed with error %d\n",
drv->name, dev->bus_id, error);
}
}
}
/**
* device_release_driver - manually detach device from driver.
* @dev: device.
*
* Manually detach device from driver.
* Note that this is called without incrementing the bus
* reference count nor taking the bus's rwsem. Be sure that
* those are accounted for before calling this function.
*/
void device_release_driver(struct device * dev)
{
struct device_driver * drv = dev->driver;
if (!drv)
return;
sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
sysfs_remove_link(&dev->kobj, "driver");
klist_remove(&dev->knode_driver);
down(&dev->sem);
if (drv->remove)
drv->remove(dev);
dev->driver = NULL;
up(&dev->sem);
}
static int __remove_driver(struct device * dev, void * unused)
{
device_release_driver(dev);
return 0;
}
/**
* driver_detach - detach driver from all devices it controls.
* @drv: driver.
*/
void driver_detach(struct device_driver * drv)
{
driver_for_each_device(drv, NULL, NULL, __remove_driver);
}
EXPORT_SYMBOL_GPL(driver_probe_device);
EXPORT_SYMBOL_GPL(device_bind_driver);
EXPORT_SYMBOL_GPL(device_release_driver);
EXPORT_SYMBOL_GPL(device_attach);
EXPORT_SYMBOL_GPL(driver_attach);
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