Line data Source code
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/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 :
20 0 : static struct device *next_device(struct klist_iter *i)
21 : {
22 0 : struct klist_node *n = klist_next(i);
23 0 : struct device *dev = NULL;
24 0 : struct device_private *dev_prv;
25 :
26 0 : if (n) {
27 0 : dev_prv = to_device_private_driver(n);
28 0 : dev = dev_prv->device;
29 : }
30 0 : 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 : */
42 0 : int driver_for_each_device(struct device_driver *drv, struct device *start,
43 : void *data, int (*fn)(struct device *, void *))
44 : {
45 0 : struct klist_iter i;
46 0 : struct device *dev;
47 0 : int error = 0;
48 :
49 0 : if (!drv)
50 : return -EINVAL;
51 :
52 0 : klist_iter_init_node(&drv->p->klist_devices, &i,
53 0 : start ? &start->p->knode_driver : NULL);
54 0 : while (!error && (dev = next_device(&i)))
55 0 : error = fn(dev, data);
56 0 : klist_iter_exit(&i);
57 0 : return error;
58 : }
59 : EXPORT_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 : */
76 0 : struct 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 0 : struct klist_iter i;
81 0 : struct device *dev;
82 :
83 0 : if (!drv || !drv->p)
84 : return NULL;
85 :
86 0 : klist_iter_init_node(&drv->p->klist_devices, &i,
87 0 : (start ? &start->p->knode_driver : NULL));
88 0 : while ((dev = next_device(&i)))
89 0 : if (match(dev, data) && get_device(dev))
90 : break;
91 0 : klist_iter_exit(&i);
92 0 : return dev;
93 : }
94 : EXPORT_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 : */
101 43 : int driver_create_file(struct device_driver *drv,
102 : const struct driver_attribute *attr)
103 : {
104 43 : int error;
105 :
106 43 : if (drv)
107 43 : error = sysfs_create_file(&drv->p->kobj, &attr->attr);
108 : else
109 : error = -EINVAL;
110 43 : return error;
111 : }
112 : EXPORT_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 : */
119 1 : void driver_remove_file(struct device_driver *drv,
120 : const struct driver_attribute *attr)
121 : {
122 1 : if (drv)
123 1 : sysfs_remove_file(&drv->p->kobj, &attr->attr);
124 1 : }
125 : EXPORT_SYMBOL_GPL(driver_remove_file);
126 :
127 30 : int driver_add_groups(struct device_driver *drv,
128 : const struct attribute_group **groups)
129 : {
130 15 : return sysfs_create_groups(&drv->p->kobj, groups);
131 : }
132 :
133 2 : void driver_remove_groups(struct device_driver *drv,
134 : const struct attribute_group **groups)
135 : {
136 1 : sysfs_remove_groups(&drv->p->kobj, groups);
137 1 : }
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 : */
147 15 : int driver_register(struct device_driver *drv)
148 : {
149 15 : int ret;
150 15 : struct device_driver *other;
151 :
152 15 : if (!drv->bus->p) {
153 0 : 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 0 : return -EINVAL;
156 : }
157 :
158 15 : if ((drv->bus->probe && drv->probe) ||
159 15 : (drv->bus->remove && drv->remove) ||
160 15 : (drv->bus->shutdown && drv->shutdown))
161 0 : pr_warn("Driver '%s' needs updating - please use "
162 : "bus_type methods\n", drv->name);
163 :
164 15 : other = driver_find(drv->name, drv->bus);
165 15 : if (other) {
166 0 : pr_err("Error: Driver '%s' is already registered, "
167 : "aborting...\n", drv->name);
168 0 : return -EBUSY;
169 : }
170 :
171 15 : ret = bus_add_driver(drv);
172 15 : if (ret)
173 : return ret;
174 15 : ret = driver_add_groups(drv, drv->groups);
175 15 : if (ret) {
176 0 : bus_remove_driver(drv);
177 0 : return ret;
178 : }
179 15 : kobject_uevent(&drv->p->kobj, KOBJ_ADD);
180 :
181 15 : return ret;
182 : }
183 : EXPORT_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 : */
191 1 : void driver_unregister(struct device_driver *drv)
192 : {
193 1 : if (!drv || !drv->p) {
194 0 : WARN(1, "Unexpected driver unregister!\n");
195 0 : return;
196 : }
197 1 : driver_remove_groups(drv, drv->groups);
198 1 : bus_remove_driver(drv);
199 : }
200 : EXPORT_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 : */
214 15 : struct device_driver *driver_find(const char *name, struct bus_type *bus)
215 : {
216 15 : struct kobject *k = kset_find_obj(bus->p->drivers_kset, name);
217 15 : struct driver_private *priv;
218 :
219 15 : if (k) {
220 : /* Drop reference added by kset_find_obj() */
221 0 : kobject_put(k);
222 0 : priv = to_driver(k);
223 0 : return priv->driver;
224 : }
225 : return NULL;
226 : }
227 : EXPORT_SYMBOL_GPL(driver_find);
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