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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * driver.c - centralized device driver management
3 *
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
6 *
7 * This file is released under the GPLv2
8 *
9 */
10
11#include <linux/config.h>
12#include <linux/device.h>
13#include <linux/module.h>
14#include <linux/errno.h>
15#include <linux/string.h>
16#include "base.h"
17
18#define to_dev(node) container_of(node, struct device, driver_list)
19#define to_drv(obj) container_of(obj, struct device_driver, kobj)
20
mochel@digitalimplant.orgfae3cd02005-03-21 10:59:56 -080021
mochel@digitalimplant.org94e7b1c2005-03-21 12:25:36 -080022static struct device * next_device(struct klist_iter * i)
23{
24 struct klist_node * n = klist_next(i);
25 return n ? container_of(n, struct device, knode_driver) : NULL;
26}
27
mochel@digitalimplant.orgfae3cd02005-03-21 10:59:56 -080028/**
29 * driver_for_each_device - Iterator for devices bound to a driver.
30 * @drv: Driver we're iterating.
Randy Dunlapc41455f2005-10-23 11:59:14 -070031 * @start: Device to begin with
mochel@digitalimplant.orgfae3cd02005-03-21 10:59:56 -080032 * @data: Data to pass to the callback.
33 * @fn: Function to call for each device.
34 *
mochel@digitalimplant.org4d12d2d2005-03-24 20:08:04 -080035 * Iterate over the @drv's list of devices calling @fn for each one.
mochel@digitalimplant.orgfae3cd02005-03-21 10:59:56 -080036 */
37
38int driver_for_each_device(struct device_driver * drv, struct device * start,
39 void * data, int (*fn)(struct device *, void *))
40{
mochel@digitalimplant.org94e7b1c2005-03-21 12:25:36 -080041 struct klist_iter i;
mochel@digitalimplant.orgfae3cd02005-03-21 10:59:56 -080042 struct device * dev;
43 int error = 0;
44
mochel@digitalimplant.org94e7b1c2005-03-21 12:25:36 -080045 if (!drv)
46 return -EINVAL;
47
48 klist_iter_init_node(&drv->klist_devices, &i,
49 start ? &start->knode_driver : NULL);
50 while ((dev = next_device(&i)) && !error)
mochel@digitalimplant.orgfae3cd02005-03-21 10:59:56 -080051 error = fn(dev, data);
mochel@digitalimplant.org94e7b1c2005-03-21 12:25:36 -080052 klist_iter_exit(&i);
mochel@digitalimplant.orgfae3cd02005-03-21 10:59:56 -080053 return error;
54}
55
gregkh@suse.de126eddf2005-03-22 12:17:13 -080056EXPORT_SYMBOL_GPL(driver_for_each_device);
mochel@digitalimplant.orgfae3cd02005-03-21 10:59:56 -080057
58
Linus Torvalds1da177e2005-04-16 15:20:36 -070059/**
Cornelia Huck0edb5862005-06-22 16:59:51 +020060 * driver_find_device - device iterator for locating a particular device.
Randy Dunlapc41455f2005-10-23 11:59:14 -070061 * @drv: The device's driver
Cornelia Huck0edb5862005-06-22 16:59:51 +020062 * @start: Device to begin with
63 * @data: Data to pass to match function
64 * @match: Callback function to check device
65 *
66 * This is similar to the driver_for_each_device() function above, but
67 * it returns a reference to a device that is 'found' for later use, as
68 * determined by the @match callback.
69 *
70 * The callback should return 0 if the device doesn't match and non-zero
71 * if it does. If the callback returns non-zero, this function will
72 * return to the caller and not iterate over any more devices.
73 */
74struct device * driver_find_device(struct device_driver *drv,
75 struct device * start, void * data,
76 int (*match)(struct device *, void *))
77{
78 struct klist_iter i;
79 struct device *dev;
80
81 if (!drv)
82 return NULL;
83
84 klist_iter_init_node(&drv->klist_devices, &i,
85 (start ? &start->knode_driver : NULL));
86 while ((dev = next_device(&i)))
87 if (match(dev, data) && get_device(dev))
88 break;
89 klist_iter_exit(&i);
90 return dev;
91}
92EXPORT_SYMBOL_GPL(driver_find_device);
93
94/**
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 * driver_create_file - create sysfs file for driver.
96 * @drv: driver.
97 * @attr: driver attribute descriptor.
98 */
99
100int driver_create_file(struct device_driver * drv, struct driver_attribute * attr)
101{
102 int error;
103 if (get_driver(drv)) {
104 error = sysfs_create_file(&drv->kobj, &attr->attr);
105 put_driver(drv);
106 } else
107 error = -EINVAL;
108 return error;
109}
110
111
112/**
113 * driver_remove_file - remove sysfs file for driver.
114 * @drv: driver.
115 * @attr: driver attribute descriptor.
116 */
117
118void driver_remove_file(struct device_driver * drv, struct driver_attribute * attr)
119{
120 if (get_driver(drv)) {
121 sysfs_remove_file(&drv->kobj, &attr->attr);
122 put_driver(drv);
123 }
124}
125
126
127/**
128 * get_driver - increment driver reference count.
129 * @drv: driver.
130 */
131struct device_driver * get_driver(struct device_driver * drv)
132{
133 return drv ? to_drv(kobject_get(&drv->kobj)) : NULL;
134}
135
136
137/**
138 * put_driver - decrement driver's refcount.
139 * @drv: driver.
140 */
141void put_driver(struct device_driver * drv)
142{
143 kobject_put(&drv->kobj);
144}
145
James Bottomley34bb61f2005-09-06 16:56:51 -0700146static void klist_devices_get(struct klist_node *n)
147{
148 struct device *dev = container_of(n, struct device, knode_driver);
149
150 get_device(dev);
151}
152
153static void klist_devices_put(struct klist_node *n)
154{
155 struct device *dev = container_of(n, struct device, knode_driver);
156
157 put_device(dev);
158}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159
160/**
161 * driver_register - register driver with bus
162 * @drv: driver to register
163 *
164 * We pass off most of the work to the bus_add_driver() call,
165 * since most of the things we have to do deal with the bus
166 * structures.
167 *
168 * The one interesting aspect is that we setup @drv->unloaded
169 * as a completion that gets complete when the driver reference
170 * count reaches 0.
171 */
172int driver_register(struct device_driver * drv)
173{
Russell King594c8282006-01-05 14:29:51 +0000174 if ((drv->bus->probe && drv->probe) ||
175 (drv->bus->remove && drv->remove) ||
176 (drv->bus->shutdown && drv->shutdown)) {
177 printk(KERN_WARNING "Driver '%s' needs updating - please use bus_type methods\n", drv->name);
178 }
James Bottomley34bb61f2005-09-06 16:56:51 -0700179 klist_init(&drv->klist_devices, klist_devices_get, klist_devices_put);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 init_completion(&drv->unloaded);
181 return bus_add_driver(drv);
182}
183
184
185/**
186 * driver_unregister - remove driver from system.
187 * @drv: driver.
188 *
189 * Again, we pass off most of the work to the bus-level call.
190 *
191 * Though, once that is done, we wait until @drv->unloaded is completed.
192 * This will block until the driver refcount reaches 0, and it is
193 * released. Only modular drivers will call this function, and we
194 * have to guarantee that it won't complete, letting the driver
195 * unload until all references are gone.
196 */
197
198void driver_unregister(struct device_driver * drv)
199{
200 bus_remove_driver(drv);
201 wait_for_completion(&drv->unloaded);
202}
203
204/**
205 * driver_find - locate driver on a bus by its name.
206 * @name: name of the driver.
207 * @bus: bus to scan for the driver.
208 *
209 * Call kset_find_obj() to iterate over list of drivers on
210 * a bus to find driver by name. Return driver if found.
211 *
212 * Note that kset_find_obj increments driver's reference count.
213 */
214struct device_driver *driver_find(const char *name, struct bus_type *bus)
215{
216 struct kobject *k = kset_find_obj(&bus->drivers, name);
217 if (k)
218 return to_drv(k);
219 return NULL;
220}
221
222EXPORT_SYMBOL_GPL(driver_register);
223EXPORT_SYMBOL_GPL(driver_unregister);
224EXPORT_SYMBOL_GPL(get_driver);
225EXPORT_SYMBOL_GPL(put_driver);
226EXPORT_SYMBOL_GPL(driver_find);
227
228EXPORT_SYMBOL_GPL(driver_create_file);
229EXPORT_SYMBOL_GPL(driver_remove_file);