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 <gregkh@suse.de>
8 * Copyright (c) 2007 Novell Inc.
9 */
10
11#include <linux/device.h>
12#include <linux/module.h>
13#include <linux/errno.h>
14#include <linux/slab.h>
15#include <linux/string.h>
16#include <linux/sysfs.h>
17#include "base.h"
18
19static struct device *next_device(struct klist_iter *i)
20{
21 struct klist_node *n = klist_next(i);
22 struct device *dev = NULL;
23 struct device_private *dev_prv;
24
25 if (n) {
26 dev_prv = to_device_private_driver(n);
27 dev = dev_prv->device;
28 }
29 return dev;
30}
31
32/**
33 * driver_for_each_device - Iterator for devices bound to a driver.
34 * @drv: Driver we're iterating.
35 * @start: Device to begin with
36 * @data: Data to pass to the callback.
37 * @fn: Function to call for each device.
38 *
39 * Iterate over the @drv's list of devices calling @fn for each one.
40 */
41int driver_for_each_device(struct device_driver *drv, struct device *start,
42 void *data, int (*fn)(struct device *, void *))
43{
44 struct klist_iter i;
45 struct device *dev;
46 int error = 0;
47
48 if (!drv)
49 return -EINVAL;
50
51 klist_iter_init_node(&drv->p->klist_devices, &i,
52 start ? &start->p->knode_driver : NULL);
53 while (!error && (dev = next_device(&i)))
54 error = fn(dev, data);
55 klist_iter_exit(&i);
56 return error;
57}
58EXPORT_SYMBOL_GPL(driver_for_each_device);
59
60/**
61 * driver_find_device - device iterator for locating a particular device.
62 * @drv: The device's driver
63 * @start: Device to begin with
64 * @data: Data to pass to match function
65 * @match: Callback function to check device
66 *
67 * This is similar to the driver_for_each_device() function above, but
68 * it returns a reference to a device that is 'found' for later use, as
69 * determined by the @match callback.
70 *
71 * The callback should return 0 if the device doesn't match and non-zero
72 * if it does. If the callback returns non-zero, this function will
73 * return to the caller and not iterate over any more devices.
74 */
75struct device *driver_find_device(struct device_driver *drv,
76 struct device *start, void *data,
77 int (*match)(struct device *dev, void *data))
78{
79 struct klist_iter i;
80 struct device *dev;
81
82 if (!drv || !drv->p)
83 return NULL;
84
85 klist_iter_init_node(&drv->p->klist_devices, &i,
86 (start ? &start->p->knode_driver : NULL));
87 while ((dev = next_device(&i)))
88 if (match(dev, data) && get_device(dev))
89 break;
90 klist_iter_exit(&i);
91 return dev;
92}
93EXPORT_SYMBOL_GPL(driver_find_device);
94
95/**
96 * driver_create_file - create sysfs file for driver.
97 * @drv: driver.
98 * @attr: driver attribute descriptor.
99 */
100int driver_create_file(struct device_driver *drv,
101 const struct driver_attribute *attr)
102{
103 int error;
104
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
126int driver_add_groups(struct device_driver *drv,
127 const struct attribute_group **groups)
128{
129 return sysfs_create_groups(&drv->p->kobj, groups);
130}
131
132void driver_remove_groups(struct device_driver *drv,
133 const struct attribute_group **groups)
134{
135 sysfs_remove_groups(&drv->p->kobj, groups);
136}
137
138/**
139 * driver_register - register driver with bus
140 * @drv: driver to register
141 *
142 * We pass off most of the work to the bus_add_driver() call,
143 * since most of the things we have to do deal with the bus
144 * structures.
145 */
146int driver_register(struct device_driver *drv)
147{
148 int ret;
149 struct device_driver *other;
150
151 if (!drv->bus->p) {
152 pr_err("Driver '%s' was unable to register with bus_type '%s' because the bus was not initialized.\n",
153 drv->name, drv->bus->name);
154 return -EINVAL;
155 }
156
157 if ((drv->bus->probe && drv->probe) ||
158 (drv->bus->remove && drv->remove) ||
159 (drv->bus->shutdown && drv->shutdown))
160 printk(KERN_WARNING "Driver '%s' needs updating - please use "
161 "bus_type methods\n", drv->name);
162
163 other = driver_find(drv->name, drv->bus);
164 if (other) {
165 printk(KERN_ERR "Error: Driver '%s' is already registered, "
166 "aborting...\n", drv->name);
167 return -EBUSY;
168 }
169
170 ret = bus_add_driver(drv);
171 if (ret)
172 return ret;
173 ret = driver_add_groups(drv, drv->groups);
174 if (ret) {
175 bus_remove_driver(drv);
176 return ret;
177 }
178 kobject_uevent(&drv->p->kobj, KOBJ_ADD);
179
180 return ret;
181}
182EXPORT_SYMBOL_GPL(driver_register);
183
184/**
185 * driver_unregister - remove driver from system.
186 * @drv: driver.
187 *
188 * Again, we pass off most of the work to the bus-level call.
189 */
190void driver_unregister(struct device_driver *drv)
191{
192 if (!drv || !drv->p) {
193 WARN(1, "Unexpected driver unregister!\n");
194 return;
195 }
196 driver_remove_groups(drv, drv->groups);
197 bus_remove_driver(drv);
198}
199EXPORT_SYMBOL_GPL(driver_unregister);
200
201/**
202 * driver_find - locate driver on a bus by its name.
203 * @name: name of the driver.
204 * @bus: bus to scan for the driver.
205 *
206 * Call kset_find_obj() to iterate over list of drivers on
207 * a bus to find driver by name. Return driver if found.
208 *
209 * This routine provides no locking to prevent the driver it returns
210 * from being unregistered or unloaded while the caller is using it.
211 * The caller is responsible for preventing this.
212 */
213struct device_driver *driver_find(const char *name, struct bus_type *bus)
214{
215 struct kobject *k = kset_find_obj(bus->p->drivers_kset, name);
216 struct driver_private *priv;
217
218 if (k) {
219 /* Drop reference added by kset_find_obj() */
220 kobject_put(k);
221 priv = to_driver(k);
222 return priv->driver;
223 }
224 return NULL;
225}
226EXPORT_SYMBOL_GPL(driver_find);
227