271 строка
6.8 KiB
C
271 строка
6.8 KiB
C
/*
|
|
* 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.)
|
|
*
|
|
* This function must be called with @dev->sem held.
|
|
*/
|
|
void device_bind_driver(struct device * dev)
|
|
{
|
|
if (klist_node_attached(&dev->knode_driver))
|
|
return;
|
|
|
|
pr_debug("bound device '%s' to driver '%s'\n",
|
|
dev->bus_id, dev->driver->name);
|
|
klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices);
|
|
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.
|
|
*
|
|
* This function returns 1 if a match is found, an error if one
|
|
* occurs (that is not -ENODEV or -ENXIO), and 0 otherwise.
|
|
*
|
|
* This function must be called with @dev->sem held. When called
|
|
* for a USB interface, @dev->parent->sem must be held as well.
|
|
*/
|
|
int driver_probe_device(struct device_driver * drv, struct device * dev)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (drv->bus->match && !drv->bus->match(dev, drv))
|
|
goto Done;
|
|
|
|
pr_debug("%s: Matched Device %s with Driver %s\n",
|
|
drv->bus->name, dev->bus_id, drv->name);
|
|
dev->driver = drv;
|
|
if (dev->bus->probe) {
|
|
ret = dev->bus->probe(dev);
|
|
if (ret) {
|
|
dev->driver = NULL;
|
|
goto ProbeFailed;
|
|
}
|
|
} else if (drv->probe) {
|
|
ret = drv->probe(dev);
|
|
if (ret) {
|
|
dev->driver = NULL;
|
|
goto ProbeFailed;
|
|
}
|
|
}
|
|
device_bind_driver(dev);
|
|
ret = 1;
|
|
pr_debug("%s: Bound Device %s to Driver %s\n",
|
|
drv->bus->name, dev->bus_id, drv->name);
|
|
goto Done;
|
|
|
|
ProbeFailed:
|
|
if (ret == -ENODEV || ret == -ENXIO) {
|
|
/* Driver matched, but didn't support device
|
|
* or device not found.
|
|
* Not an error; keep going.
|
|
*/
|
|
ret = 0;
|
|
} else {
|
|
/* driver matched but the probe failed */
|
|
printk(KERN_WARNING
|
|
"%s: probe of %s failed with error %d\n",
|
|
drv->name, dev->bus_id, ret);
|
|
}
|
|
Done:
|
|
return ret;
|
|
}
|
|
|
|
static int __device_attach(struct device_driver * drv, void * data)
|
|
{
|
|
struct device * dev = data;
|
|
return driver_probe_device(drv, dev);
|
|
}
|
|
|
|
/**
|
|
* 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.
|
|
*
|
|
* Returns 1 if the device was bound to a driver;
|
|
* 0 if no matching device was found; error code otherwise.
|
|
*
|
|
* When called for a USB interface, @dev->parent->sem must be held.
|
|
*/
|
|
int device_attach(struct device * dev)
|
|
{
|
|
int ret = 0;
|
|
|
|
down(&dev->sem);
|
|
if (dev->driver) {
|
|
device_bind_driver(dev);
|
|
ret = 1;
|
|
} else
|
|
ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
|
|
up(&dev->sem);
|
|
return ret;
|
|
}
|
|
|
|
static int __driver_attach(struct device * dev, void * data)
|
|
{
|
|
struct device_driver * drv = data;
|
|
|
|
/*
|
|
* Lock device and try to bind to it. We drop the error
|
|
* here and always return 0, because we need to keep trying
|
|
* to bind to devices and some drivers will return an error
|
|
* simply if it didn't support the device.
|
|
*
|
|
* driver_probe_device() will spit a warning if there
|
|
* is an error.
|
|
*/
|
|
|
|
if (dev->parent) /* Needed for USB */
|
|
down(&dev->parent->sem);
|
|
down(&dev->sem);
|
|
if (!dev->driver)
|
|
driver_probe_device(drv, dev);
|
|
up(&dev->sem);
|
|
if (dev->parent)
|
|
up(&dev->parent->sem);
|
|
|
|
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.
|
|
*/
|
|
void driver_attach(struct device_driver * drv)
|
|
{
|
|
bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
|
|
}
|
|
|
|
/**
|
|
* device_release_driver - manually detach device from driver.
|
|
* @dev: device.
|
|
*
|
|
* Manually detach device from driver.
|
|
*
|
|
* __device_release_driver() must be called with @dev->sem held.
|
|
* When called for a USB interface, @dev->parent->sem must be held
|
|
* as well.
|
|
*/
|
|
|
|
static void __device_release_driver(struct device * dev)
|
|
{
|
|
struct device_driver * drv;
|
|
|
|
drv = dev->driver;
|
|
if (drv) {
|
|
get_driver(drv);
|
|
sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
|
|
sysfs_remove_link(&dev->kobj, "driver");
|
|
klist_remove(&dev->knode_driver);
|
|
|
|
if (dev->bus && dev->bus->remove)
|
|
dev->bus->remove(dev);
|
|
else if (drv->remove)
|
|
drv->remove(dev);
|
|
dev->driver = NULL;
|
|
put_driver(drv);
|
|
}
|
|
}
|
|
|
|
void device_release_driver(struct device * dev)
|
|
{
|
|
/*
|
|
* If anyone calls device_release_driver() recursively from
|
|
* within their ->remove callback for the same device, they
|
|
* will deadlock right here.
|
|
*/
|
|
down(&dev->sem);
|
|
__device_release_driver(dev);
|
|
up(&dev->sem);
|
|
}
|
|
|
|
|
|
/**
|
|
* driver_detach - detach driver from all devices it controls.
|
|
* @drv: driver.
|
|
*/
|
|
void driver_detach(struct device_driver * drv)
|
|
{
|
|
struct device * dev;
|
|
|
|
for (;;) {
|
|
spin_lock(&drv->klist_devices.k_lock);
|
|
if (list_empty(&drv->klist_devices.k_list)) {
|
|
spin_unlock(&drv->klist_devices.k_lock);
|
|
break;
|
|
}
|
|
dev = list_entry(drv->klist_devices.k_list.prev,
|
|
struct device, knode_driver.n_node);
|
|
get_device(dev);
|
|
spin_unlock(&drv->klist_devices.k_lock);
|
|
|
|
if (dev->parent) /* Needed for USB */
|
|
down(&dev->parent->sem);
|
|
down(&dev->sem);
|
|
if (dev->driver == drv)
|
|
__device_release_driver(dev);
|
|
up(&dev->sem);
|
|
if (dev->parent)
|
|
up(&dev->parent->sem);
|
|
put_device(dev);
|
|
}
|
|
}
|
|
|
|
|
|
EXPORT_SYMBOL_GPL(device_bind_driver);
|
|
EXPORT_SYMBOL_GPL(device_release_driver);
|
|
EXPORT_SYMBOL_GPL(device_attach);
|
|
EXPORT_SYMBOL_GPL(driver_attach);
|
|
|