projects/linux·blob v5.13 · refs

227 lines · 5.8 KiB

1// SPDX-License-Identifier: GPL-2.0
2/*
3 * driver.c - centralized device driver management
4 *
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
7 * Copyright (c) 2007 Greg Kroah-Hartman <[email protected]>
8 * Copyright (c) 2007 Novell Inc.
9 */
10
11#include <linux/device/driver.h>
12#include <linux/device.h>
13#include <linux/module.h>
14#include <linux/errno.h>
15#include <linux/slab.h>
16#include <linux/string.h>
17#include <linux/sysfs.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 (!error && (dev = next_device(&i)))
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, const void *data,
78 int (*match)(struct device *dev, const void *data))
79{
80 struct klist_iter i;
81 struct device *dev;
82
83 if (!drv || !drv->p)
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
106 if (drv)
107 error = sysfs_create_file(&drv->p->kobj, &attr->attr);
108 else
109 error = -EINVAL;
110 return error;
111}
112EXPORT_SYMBOL_GPL(driver_create_file);
113
114/**
115 * driver_remove_file - remove sysfs file for driver.
116 * @drv: driver.
117 * @attr: driver attribute descriptor.
118 */
119void driver_remove_file(struct device_driver *drv,
120 const struct driver_attribute *attr)
121{
122 if (drv)
123 sysfs_remove_file(&drv->p->kobj, &attr->attr);
124}
125EXPORT_SYMBOL_GPL(driver_remove_file);
126
127int driver_add_groups(struct device_driver *drv,
128 const struct attribute_group **groups)
129{
130 return sysfs_create_groups(&drv->p->kobj, groups);
131}
132
133void driver_remove_groups(struct device_driver *drv,
134 const struct attribute_group **groups)
135{
136 sysfs_remove_groups(&drv->p->kobj, groups);
137}
138
139/**
140 * driver_register - register driver with bus
141 * @drv: driver to register
142 *
143 * We pass off most of the work to the bus_add_driver() call,
144 * since most of the things we have to do deal with the bus
145 * structures.
146 */
147int driver_register(struct device_driver *drv)
148{
149 int ret;
150 struct device_driver *other;
151
152 if (!drv->bus->p) {
153 pr_err("Driver '%s' was unable to register with bus_type '%s' because the bus was not initialized.\n",
154 drv->name, drv->bus->name);
155 return -EINVAL;
156 }
157
158 if ((drv->bus->probe && drv->probe) ||
159 (drv->bus->remove && drv->remove) ||
160 (drv->bus->shutdown && drv->shutdown))
161 pr_warn("Driver '%s' needs updating - please use "
162 "bus_type methods\n", drv->name);
163
164 other = driver_find(drv->name, drv->bus);
165 if (other) {
166 pr_err("Error: Driver '%s' is already registered, "
167 "aborting...\n", drv->name);
168 return -EBUSY;
169 }
170
171 ret = bus_add_driver(drv);
172 if (ret)
173 return ret;
174 ret = driver_add_groups(drv, drv->groups);
175 if (ret) {
176 bus_remove_driver(drv);
177 return ret;
178 }
179 kobject_uevent(&drv->p->kobj, KOBJ_ADD);
180
181 return ret;
182}
183EXPORT_SYMBOL_GPL(driver_register);
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 */
191void driver_unregister(struct device_driver *drv)
192{
193 if (!drv || !drv->p) {
194 WARN(1, "Unexpected driver unregister!\n");
195 return;
196 }
197 driver_remove_groups(drv, drv->groups);
198 bus_remove_driver(drv);
199}
200EXPORT_SYMBOL_GPL(driver_unregister);
201
202/**
203 * driver_find - locate driver on a bus by its name.
204 * @name: name of the driver.
205 * @bus: bus to scan for the driver.
206 *
207 * Call kset_find_obj() to iterate over list of drivers on
208 * a bus to find driver by name. Return driver if found.
209 *
210 * This routine provides no locking to prevent the driver it returns
211 * from being unregistered or unloaded while the caller is using it.
212 * The caller is responsible for preventing this.
213 */
214struct device_driver *driver_find(const char *name, struct bus_type *bus)
215{
216 struct kobject *k = kset_find_obj(bus->p->drivers_kset, name);
217 struct driver_private *priv;
218
219 if (k) {
220 /* Drop reference added by kset_find_obj() */
221 kobject_put(k);
222 priv = to_driver(k);
223 return priv->driver;
224 }
225 return NULL;
226}
227EXPORT_SYMBOL_GPL(driver_find);