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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 : :
19 : : static struct device *next_device(struct klist_iter *i)
20 : : {
21 : 0 : struct klist_node *n = klist_next(i);
22 : : struct device *dev = NULL;
23 : : struct device_private *dev_prv;
24 : :
25 [ # # # # ]: 0 : if (n) {
26 : : dev_prv = to_device_private_driver(n);
27 : 0 : 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 : : */
41 : 0 : int 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 [ # # ]: 0 : if (!drv)
49 : : return -EINVAL;
50 : :
51 [ # # ]: 0 : klist_iter_init_node(&drv->p->klist_devices, &i,
52 : 0 : start ? &start->p->knode_driver : NULL);
53 [ # # # # ]: 0 : while (!error && (dev = next_device(&i)))
54 : 0 : error = fn(dev, data);
55 : 0 : klist_iter_exit(&i);
56 : 0 : return error;
57 : : }
58 : : EXPORT_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 : : */
75 : 0 : struct device *driver_find_device(struct device_driver *drv,
76 : : struct device *start, const void *data,
77 : : int (*match)(struct device *dev, const void *data))
78 : : {
79 : : struct klist_iter i;
80 : : struct device *dev;
81 : :
82 [ # # # # ]: 0 : if (!drv || !drv->p)
83 : : return NULL;
84 : :
85 [ # # ]: 0 : klist_iter_init_node(&drv->p->klist_devices, &i,
86 : 0 : (start ? &start->p->knode_driver : NULL));
87 [ # # ]: 0 : while ((dev = next_device(&i)))
88 [ # # # # ]: 0 : if (match(dev, data) && get_device(dev))
89 : : break;
90 : 0 : klist_iter_exit(&i);
91 : 0 : return dev;
92 : : }
93 : : EXPORT_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 : : */
100 : 43677 : int driver_create_file(struct device_driver *drv,
101 : : const struct driver_attribute *attr)
102 : : {
103 : : int error;
104 : :
105 [ + - ]: 43677 : if (drv)
106 : 43677 : error = sysfs_create_file(&drv->p->kobj, &attr->attr);
107 : : else
108 : : error = -EINVAL;
109 : 43677 : return error;
110 : : }
111 : : EXPORT_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 : : */
118 : 0 : void driver_remove_file(struct device_driver *drv,
119 : : const struct driver_attribute *attr)
120 : : {
121 [ # # ]: 0 : if (drv)
122 : 0 : sysfs_remove_file(&drv->p->kobj, &attr->attr);
123 : 0 : }
124 : : EXPORT_SYMBOL_GPL(driver_remove_file);
125 : :
126 : 14490 : int driver_add_groups(struct device_driver *drv,
127 : : const struct attribute_group **groups)
128 : : {
129 : 28980 : return sysfs_create_groups(&drv->p->kobj, groups);
130 : : }
131 : :
132 : 0 : void driver_remove_groups(struct device_driver *drv,
133 : : const struct attribute_group **groups)
134 : : {
135 : 0 : sysfs_remove_groups(&drv->p->kobj, groups);
136 : 0 : }
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 : : */
146 : 14490 : int driver_register(struct device_driver *drv)
147 : : {
148 : : int ret;
149 : : struct device_driver *other;
150 : :
151 [ - + ]: 14490 : if (!drv->bus->p) {
152 : 0 : 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 : 0 : return -EINVAL;
155 : : }
156 : :
157 [ + + + - : 28980 : if ((drv->bus->probe && drv->probe) ||
+ + ]
158 [ + - + + ]: 29808 : (drv->bus->remove && drv->remove) ||
159 [ - + ]: 15111 : (drv->bus->shutdown && drv->shutdown))
160 : 0 : printk(KERN_WARNING "Driver '%s' needs updating - please use "
161 : : "bus_type methods\n", drv->name);
162 : :
163 : 14490 : other = driver_find(drv->name, drv->bus);
164 [ - + ]: 14490 : if (other) {
165 : 0 : printk(KERN_ERR "Error: Driver '%s' is already registered, "
166 : : "aborting...\n", drv->name);
167 : 0 : return -EBUSY;
168 : : }
169 : :
170 : 14490 : ret = bus_add_driver(drv);
171 [ + - ]: 14490 : if (ret)
172 : : return ret;
173 : 14490 : ret = driver_add_groups(drv, drv->groups);
174 [ - + ]: 14490 : if (ret) {
175 : 0 : bus_remove_driver(drv);
176 : 0 : return ret;
177 : : }
178 : 14490 : kobject_uevent(&drv->p->kobj, KOBJ_ADD);
179 : :
180 : 14490 : return ret;
181 : : }
182 : : EXPORT_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 : : */
190 : 0 : void driver_unregister(struct device_driver *drv)
191 : : {
192 [ # # # # ]: 0 : if (!drv || !drv->p) {
193 : 0 : WARN(1, "Unexpected driver unregister!\n");
194 : 0 : return;
195 : : }
196 : 0 : driver_remove_groups(drv, drv->groups);
197 : 0 : bus_remove_driver(drv);
198 : : }
199 : : EXPORT_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 : : */
213 : 14490 : struct device_driver *driver_find(const char *name, struct bus_type *bus)
214 : : {
215 : 14490 : struct kobject *k = kset_find_obj(bus->p->drivers_kset, name);
216 : : struct driver_private *priv;
217 : :
218 [ - + ]: 14490 : if (k) {
219 : : /* Drop reference added by kset_find_obj() */
220 : 0 : kobject_put(k);
221 : : priv = to_driver(k);
222 : 0 : return priv->driver;
223 : : }
224 : : return NULL;
225 : : }
226 : : EXPORT_SYMBOL_GPL(driver_find);
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