(2006-08-06) rescue-bootcd

extra/linux-2.6.10/drivers/base/driver.c

@@ -0,0 +1,139 @@
+/*
+ * 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/config.h>
+#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)
+
+/**
+ *	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 initialize @drv->unload_sem
+ *	to a locked state here. It will be unlocked when the driver
+ *	reference count reaches 0.
+ */
+int driver_register(struct device_driver * drv)
+{
+	INIT_LIST_HEAD(&drv->devices);
+	init_MUTEX_LOCKED(&drv->unload_sem);
+	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 attempt to take @drv->unload_sem.
+ *	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);
+	down(&drv->unload_sem);
+	up(&drv->unload_sem);
+}
+
+/**
+ *	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);