projects/linux·blob v3.2 · refs

291 lines · 6.8 KiB

1/*
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 * Copyright (c) 2007 Greg Kroah-Hartman <[email protected]>
7 * Copyright (c) 2007 Novell Inc.
8 *
9 * This file is released under the GPLv2
10 *
11 */
12
13#include <linux/device.h>
14#include <linux/module.h>
15#include <linux/errno.h>
16#include <linux/slab.h>
17#include <linux/string.h>
18#include "base.h"
19
20static struct device *next_device(struct klist_iter *i)
21{
22 struct klist_node *n = klist_next(i);
23 struct device *dev = NULL;
24 struct device_private *dev_prv;
25
26 if (n) {
27 dev_prv = to_device_private_driver(n);
28 dev = dev_prv->device;
29 }
30 return dev;
31}
32
33/**
34 * driver_for_each_device - Iterator for devices bound to a driver.
35 * @drv: Driver we're iterating.
36 * @start: Device to begin with
37 * @data: Data to pass to the callback.
38 * @fn: Function to call for each device.
39 *
40 * Iterate over the @drv's list of devices calling @fn for each one.
41 */
42int driver_for_each_device(struct device_driver *drv, struct device *start,
43 void *data, int (*fn)(struct device *, void *))
44{
45 struct klist_iter i;
46 struct device *dev;
47 int error = 0;
48
49 if (!drv)
50 return -EINVAL;
51
52 klist_iter_init_node(&drv->p->klist_devices, &i,
53 start ? &start->p->knode_driver : NULL);
54 while ((dev = next_device(&i)) && !error)
55 error = fn(dev, data);
56 klist_iter_exit(&i);
57 return error;
58}
59EXPORT_SYMBOL_GPL(driver_for_each_device);
60
61/**
62 * driver_find_device - device iterator for locating a particular device.
63 * @drv: The device's driver
64 * @start: Device to begin with
65 * @data: Data to pass to match function
66 * @match: Callback function to check device
67 *
68 * This is similar to the driver_for_each_device() function above, but
69 * it returns a reference to a device that is 'found' for later use, as
70 * determined by the @match callback.
71 *
72 * The callback should return 0 if the device doesn't match and non-zero
73 * if it does. If the callback returns non-zero, this function will
74 * return to the caller and not iterate over any more devices.
75 */
76struct device *driver_find_device(struct device_driver *drv,
77 struct device *start, void *data,
78 int (*match)(struct device *dev, void *data))
79{
80 struct klist_iter i;
81 struct device *dev;
82
83 if (!drv)
84 return NULL;
85
86 klist_iter_init_node(&drv->p->klist_devices, &i,
87 (start ? &start->p->knode_driver : NULL));
88 while ((dev = next_device(&i)))
89 if (match(dev, data) && get_device(dev))
90 break;
91 klist_iter_exit(&i);
92 return dev;
93}
94EXPORT_SYMBOL_GPL(driver_find_device);
95
96/**
97 * driver_create_file - create sysfs file for driver.
98 * @drv: driver.
99 * @attr: driver attribute descriptor.
100 */
101int driver_create_file(struct device_driver *drv,
102 const struct driver_attribute *attr)
103{
104 int error;
105 if (drv)
106 error = sysfs_create_file(&drv->p->kobj, &attr->attr);
107 else
108 error = -EINVAL;
109 return error;
110}
111EXPORT_SYMBOL_GPL(driver_create_file);
112
113/**
114 * driver_remove_file - remove sysfs file for driver.
115 * @drv: driver.
116 * @attr: driver attribute descriptor.
117 */
118void driver_remove_file(struct device_driver *drv,
119 const struct driver_attribute *attr)
120{
121 if (drv)
122 sysfs_remove_file(&drv->p->kobj, &attr->attr);
123}
124EXPORT_SYMBOL_GPL(driver_remove_file);
125
126/**
127 * driver_add_kobj - add a kobject below the specified driver
128 * @drv: requesting device driver
129 * @kobj: kobject to add below this driver
130 * @fmt: format string that names the kobject
131 *
132 * You really don't want to do this, this is only here due to one looney
133 * iseries driver, go poke those developers if you are annoyed about
134 * this...
135 */
136int driver_add_kobj(struct device_driver *drv, struct kobject *kobj,
137 const char *fmt, ...)
138{
139 va_list args;
140 char *name;
141 int ret;
142
143 va_start(args, fmt);
144 name = kvasprintf(GFP_KERNEL, fmt, args);
145 va_end(args);
146
147 if (!name)
148 return -ENOMEM;
149
150 ret = kobject_add(kobj, &drv->p->kobj, "%s", name);
151 kfree(name);
152 return ret;
153}
154EXPORT_SYMBOL_GPL(driver_add_kobj);
155
156/**
157 * get_driver - increment driver reference count.
158 * @drv: driver.
159 */
160struct device_driver *get_driver(struct device_driver *drv)
161{
162 if (drv) {
163 struct driver_private *priv;
164 struct kobject *kobj;
165
166 kobj = kobject_get(&drv->p->kobj);
167 priv = to_driver(kobj);
168 return priv->driver;
169 }
170 return NULL;
171}
172EXPORT_SYMBOL_GPL(get_driver);
173
174/**
175 * put_driver - decrement driver's refcount.
176 * @drv: driver.
177 */
178void put_driver(struct device_driver *drv)
179{
180 kobject_put(&drv->p->kobj);
181}
182EXPORT_SYMBOL_GPL(put_driver);
183
184static int driver_add_groups(struct device_driver *drv,
185 const struct attribute_group **groups)
186{
187 int error = 0;
188 int i;
189
190 if (groups) {
191 for (i = 0; groups[i]; i++) {
192 error = sysfs_create_group(&drv->p->kobj, groups[i]);
193 if (error) {
194 while (--i >= 0)
195 sysfs_remove_group(&drv->p->kobj,
196 groups[i]);
197 break;
198 }
199 }
200 }
201 return error;
202}
203
204static void driver_remove_groups(struct device_driver *drv,
205 const struct attribute_group **groups)
206{
207 int i;
208
209 if (groups)
210 for (i = 0; groups[i]; i++)
211 sysfs_remove_group(&drv->p->kobj, groups[i]);
212}
213
214/**
215 * driver_register - register driver with bus
216 * @drv: driver to register
217 *
218 * We pass off most of the work to the bus_add_driver() call,
219 * since most of the things we have to do deal with the bus
220 * structures.
221 */
222int driver_register(struct device_driver *drv)
223{
224 int ret;
225 struct device_driver *other;
226
227 BUG_ON(!drv->bus->p);
228
229 if ((drv->bus->probe && drv->probe) ||
230 (drv->bus->remove && drv->remove) ||
231 (drv->bus->shutdown && drv->shutdown))
232 printk(KERN_WARNING "Driver '%s' needs updating - please use "
233 "bus_type methods\n", drv->name);
234
235 other = driver_find(drv->name, drv->bus);
236 if (other) {
237 put_driver(other);
238 printk(KERN_ERR "Error: Driver '%s' is already registered, "
239 "aborting...\n", drv->name);
240 return -EBUSY;
241 }
242
243 ret = bus_add_driver(drv);
244 if (ret)
245 return ret;
246 ret = driver_add_groups(drv, drv->groups);
247 if (ret)
248 bus_remove_driver(drv);
249 return ret;
250}
251EXPORT_SYMBOL_GPL(driver_register);
252
253/**
254 * driver_unregister - remove driver from system.
255 * @drv: driver.
256 *
257 * Again, we pass off most of the work to the bus-level call.
258 */
259void driver_unregister(struct device_driver *drv)
260{
261 if (!drv || !drv->p) {
262 WARN(1, "Unexpected driver unregister!\n");
263 return;
264 }
265 driver_remove_groups(drv, drv->groups);
266 bus_remove_driver(drv);
267}
268EXPORT_SYMBOL_GPL(driver_unregister);
269
270/**
271 * driver_find - locate driver on a bus by its name.
272 * @name: name of the driver.
273 * @bus: bus to scan for the driver.
274 *
275 * Call kset_find_obj() to iterate over list of drivers on
276 * a bus to find driver by name. Return driver if found.
277 *
278 * Note that kset_find_obj increments driver's reference count.
279 */
280struct device_driver *driver_find(const char *name, struct bus_type *bus)
281{
282 struct kobject *k = kset_find_obj(bus->p->drivers_kset, name);
283 struct driver_private *priv;
284
285 if (k) {
286 priv = to_driver(k);
287 return priv->driver;
288 }
289 return NULL;
290}
291EXPORT_SYMBOL_GPL(driver_find);