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989d42e8 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
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 | |
e5dd1278 GKH |
7 | * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de> |
8 | * Copyright (c) 2007 Novell Inc. | |
1da177e4 LT |
9 | */ |
10 | ||
4c002c97 | 11 | #include <linux/device/driver.h> |
1da177e4 LT |
12 | #include <linux/device.h> |
13 | #include <linux/module.h> | |
14 | #include <linux/errno.h> | |
5a0e3ad6 | 15 | #include <linux/slab.h> |
1da177e4 | 16 | #include <linux/string.h> |
63967685 | 17 | #include <linux/sysfs.h> |
1da177e4 LT |
18 | #include "base.h" |
19 | ||
4a3ad20c | 20 | static struct device *next_device(struct klist_iter *i) |
94e7b1c5 | 21 | { |
4a3ad20c | 22 | struct klist_node *n = klist_next(i); |
8940b4f3 GKH |
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; | |
94e7b1c5 | 31 | } |
32 | ||
6c2f4211 KK |
33 | /** |
34 | * driver_set_override() - Helper to set or clear driver override. | |
35 | * @dev: Device to change | |
36 | * @override: Address of string to change (e.g. &device->driver_override); | |
37 | * The contents will be freed and hold newly allocated override. | |
38 | * @s: NUL-terminated string, new driver name to force a match, pass empty | |
39 | * string to clear it ("" or "\n", where the latter is only for sysfs | |
40 | * interface). | |
41 | * @len: length of @s | |
42 | * | |
43 | * Helper to set or clear driver override in a device, intended for the cases | |
44 | * when the driver_override field is allocated by driver/bus code. | |
45 | * | |
46 | * Returns: 0 on success or a negative error code on failure. | |
47 | */ | |
48 | int driver_set_override(struct device *dev, const char **override, | |
49 | const char *s, size_t len) | |
50 | { | |
51 | const char *new, *old; | |
52 | char *cp; | |
53 | ||
54 | if (!override || !s) | |
55 | return -EINVAL; | |
56 | ||
57 | /* | |
58 | * The stored value will be used in sysfs show callback (sysfs_emit()), | |
59 | * which has a length limit of PAGE_SIZE and adds a trailing newline. | |
60 | * Thus we can store one character less to avoid truncation during sysfs | |
61 | * show. | |
62 | */ | |
63 | if (len >= (PAGE_SIZE - 1)) | |
64 | return -EINVAL; | |
65 | ||
5666a274 GKH |
66 | /* |
67 | * Compute the real length of the string in case userspace sends us a | |
68 | * bunch of \0 characters like python likes to do. | |
69 | */ | |
70 | len = strlen(s); | |
71 | ||
6c2f4211 KK |
72 | if (!len) { |
73 | /* Empty string passed - clear override */ | |
74 | device_lock(dev); | |
75 | old = *override; | |
76 | *override = NULL; | |
77 | device_unlock(dev); | |
78 | kfree(old); | |
79 | ||
80 | return 0; | |
81 | } | |
82 | ||
83 | cp = strnchr(s, len, '\n'); | |
84 | if (cp) | |
85 | len = cp - s; | |
86 | ||
87 | new = kstrndup(s, len, GFP_KERNEL); | |
88 | if (!new) | |
89 | return -ENOMEM; | |
90 | ||
91 | device_lock(dev); | |
92 | old = *override; | |
93 | if (cp != s) { | |
94 | *override = new; | |
95 | } else { | |
96 | /* "\n" passed - clear override */ | |
97 | kfree(new); | |
98 | *override = NULL; | |
99 | } | |
100 | device_unlock(dev); | |
101 | ||
102 | kfree(old); | |
103 | ||
104 | return 0; | |
105 | } | |
106 | EXPORT_SYMBOL_GPL(driver_set_override); | |
107 | ||
fae3cd00 | 108 | /** |
4a3ad20c GKH |
109 | * driver_for_each_device - Iterator for devices bound to a driver. |
110 | * @drv: Driver we're iterating. | |
111 | * @start: Device to begin with | |
112 | * @data: Data to pass to the callback. | |
113 | * @fn: Function to call for each device. | |
fae3cd00 | 114 | * |
4a3ad20c | 115 | * Iterate over the @drv's list of devices calling @fn for each one. |
fae3cd00 | 116 | */ |
4a3ad20c GKH |
117 | int driver_for_each_device(struct device_driver *drv, struct device *start, |
118 | void *data, int (*fn)(struct device *, void *)) | |
fae3cd00 | 119 | { |
94e7b1c5 | 120 | struct klist_iter i; |
4a3ad20c | 121 | struct device *dev; |
fae3cd00 | 122 | int error = 0; |
123 | ||
94e7b1c5 | 124 | if (!drv) |
125 | return -EINVAL; | |
126 | ||
7cd9c9bb GKH |
127 | klist_iter_init_node(&drv->p->klist_devices, &i, |
128 | start ? &start->p->knode_driver : NULL); | |
93ead7c9 | 129 | while (!error && (dev = next_device(&i))) |
7cd9c9bb GKH |
130 | error = fn(dev, data); |
131 | klist_iter_exit(&i); | |
fae3cd00 | 132 | return error; |
133 | } | |
126eddfb | 134 | EXPORT_SYMBOL_GPL(driver_for_each_device); |
fae3cd00 | 135 | |
0edb5860 CH |
136 | /** |
137 | * driver_find_device - device iterator for locating a particular device. | |
c41455fb | 138 | * @drv: The device's driver |
0edb5860 CH |
139 | * @start: Device to begin with |
140 | * @data: Data to pass to match function | |
141 | * @match: Callback function to check device | |
142 | * | |
143 | * This is similar to the driver_for_each_device() function above, but | |
144 | * it returns a reference to a device that is 'found' for later use, as | |
145 | * determined by the @match callback. | |
146 | * | |
147 | * The callback should return 0 if the device doesn't match and non-zero | |
148 | * if it does. If the callback returns non-zero, this function will | |
149 | * return to the caller and not iterate over any more devices. | |
150 | */ | |
4a3ad20c | 151 | struct device *driver_find_device(struct device_driver *drv, |
92ce7e83 SP |
152 | struct device *start, const void *data, |
153 | int (*match)(struct device *dev, const void *data)) | |
0edb5860 CH |
154 | { |
155 | struct klist_iter i; | |
156 | struct device *dev; | |
157 | ||
094e47e9 | 158 | if (!drv || !drv->p) |
0edb5860 CH |
159 | return NULL; |
160 | ||
7cd9c9bb GKH |
161 | klist_iter_init_node(&drv->p->klist_devices, &i, |
162 | (start ? &start->p->knode_driver : NULL)); | |
0edb5860 CH |
163 | while ((dev = next_device(&i))) |
164 | if (match(dev, data) && get_device(dev)) | |
165 | break; | |
166 | klist_iter_exit(&i); | |
167 | return dev; | |
168 | } | |
169 | EXPORT_SYMBOL_GPL(driver_find_device); | |
170 | ||
1da177e4 | 171 | /** |
4a3ad20c GKH |
172 | * driver_create_file - create sysfs file for driver. |
173 | * @drv: driver. | |
174 | * @attr: driver attribute descriptor. | |
1da177e4 | 175 | */ |
4a3ad20c | 176 | int driver_create_file(struct device_driver *drv, |
099c2f21 | 177 | const struct driver_attribute *attr) |
1da177e4 LT |
178 | { |
179 | int error; | |
74642c6c | 180 | |
0c98b19f | 181 | if (drv) |
e5dd1278 | 182 | error = sysfs_create_file(&drv->p->kobj, &attr->attr); |
0c98b19f | 183 | else |
1da177e4 LT |
184 | error = -EINVAL; |
185 | return error; | |
186 | } | |
4a3ad20c | 187 | EXPORT_SYMBOL_GPL(driver_create_file); |
1da177e4 LT |
188 | |
189 | /** | |
4a3ad20c GKH |
190 | * driver_remove_file - remove sysfs file for driver. |
191 | * @drv: driver. | |
192 | * @attr: driver attribute descriptor. | |
1da177e4 | 193 | */ |
4a3ad20c | 194 | void driver_remove_file(struct device_driver *drv, |
099c2f21 | 195 | const struct driver_attribute *attr) |
1da177e4 | 196 | { |
0c98b19f | 197 | if (drv) |
e5dd1278 | 198 | sysfs_remove_file(&drv->p->kobj, &attr->attr); |
1da177e4 | 199 | } |
4a3ad20c | 200 | EXPORT_SYMBOL_GPL(driver_remove_file); |
1da177e4 | 201 | |
ed0617b5 GKH |
202 | int driver_add_groups(struct device_driver *drv, |
203 | const struct attribute_group **groups) | |
57c74534 | 204 | { |
3e9b2bae | 205 | return sysfs_create_groups(&drv->p->kobj, groups); |
57c74534 CH |
206 | } |
207 | ||
ed0617b5 GKH |
208 | void driver_remove_groups(struct device_driver *drv, |
209 | const struct attribute_group **groups) | |
57c74534 | 210 | { |
3e9b2bae | 211 | sysfs_remove_groups(&drv->p->kobj, groups); |
57c74534 CH |
212 | } |
213 | ||
1da177e4 | 214 | /** |
4a3ad20c GKH |
215 | * driver_register - register driver with bus |
216 | * @drv: driver to register | |
1da177e4 | 217 | * |
4a3ad20c GKH |
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. | |
1da177e4 | 221 | */ |
4a3ad20c | 222 | int driver_register(struct device_driver *drv) |
1da177e4 | 223 | { |
57c74534 | 224 | int ret; |
16dc42e0 | 225 | struct device_driver *other; |
57c74534 | 226 | |
0dda2bb6 FS |
227 | if (!drv->bus->p) { |
228 | pr_err("Driver '%s' was unable to register with bus_type '%s' because the bus was not initialized.\n", | |
229 | drv->name, drv->bus->name); | |
230 | return -EINVAL; | |
231 | } | |
f48f3feb | 232 | |
594c8281 RK |
233 | if ((drv->bus->probe && drv->probe) || |
234 | (drv->bus->remove && drv->remove) || | |
4a3ad20c | 235 | (drv->bus->shutdown && drv->shutdown)) |
5962b8b2 | 236 | pr_warn("Driver '%s' needs updating - please use " |
4a3ad20c | 237 | "bus_type methods\n", drv->name); |
16dc42e0 SS |
238 | |
239 | other = driver_find(drv->name, drv->bus); | |
240 | if (other) { | |
5962b8b2 | 241 | pr_err("Error: Driver '%s' is already registered, " |
16dc42e0 | 242 | "aborting...\n", drv->name); |
39acbc12 | 243 | return -EBUSY; |
16dc42e0 SS |
244 | } |
245 | ||
57c74534 CH |
246 | ret = bus_add_driver(drv); |
247 | if (ret) | |
248 | return ret; | |
249 | ret = driver_add_groups(drv, drv->groups); | |
a14af325 | 250 | if (ret) { |
57c74534 | 251 | bus_remove_driver(drv); |
a14af325 SO |
252 | return ret; |
253 | } | |
5a7689fd | 254 | kobject_uevent(&drv->p->kobj, KOBJ_ADD); |
2b28a1a8 | 255 | deferred_probe_extend_timeout(); |
5a7689fd | 256 | |
57c74534 | 257 | return ret; |
1da177e4 | 258 | } |
4a3ad20c | 259 | EXPORT_SYMBOL_GPL(driver_register); |
1da177e4 | 260 | |
1da177e4 | 261 | /** |
4a3ad20c GKH |
262 | * driver_unregister - remove driver from system. |
263 | * @drv: driver. | |
1da177e4 | 264 | * |
4a3ad20c | 265 | * Again, we pass off most of the work to the bus-level call. |
1da177e4 | 266 | */ |
4a3ad20c | 267 | void driver_unregister(struct device_driver *drv) |
1da177e4 | 268 | { |
5c8563d7 KS |
269 | if (!drv || !drv->p) { |
270 | WARN(1, "Unexpected driver unregister!\n"); | |
271 | return; | |
272 | } | |
57c74534 | 273 | driver_remove_groups(drv, drv->groups); |
1da177e4 | 274 | bus_remove_driver(drv); |
1da177e4 | 275 | } |
4a3ad20c | 276 | EXPORT_SYMBOL_GPL(driver_unregister); |
1da177e4 LT |
277 | |
278 | /** | |
4a3ad20c GKH |
279 | * driver_find - locate driver on a bus by its name. |
280 | * @name: name of the driver. | |
281 | * @bus: bus to scan for the driver. | |
1da177e4 | 282 | * |
4a3ad20c GKH |
283 | * Call kset_find_obj() to iterate over list of drivers on |
284 | * a bus to find driver by name. Return driver if found. | |
1da177e4 | 285 | * |
fde25a9b AS |
286 | * This routine provides no locking to prevent the driver it returns |
287 | * from being unregistered or unloaded while the caller is using it. | |
288 | * The caller is responsible for preventing this. | |
1da177e4 LT |
289 | */ |
290 | struct device_driver *driver_find(const char *name, struct bus_type *bus) | |
291 | { | |
c6f7e72a | 292 | struct kobject *k = kset_find_obj(bus->p->drivers_kset, name); |
e5dd1278 GKH |
293 | struct driver_private *priv; |
294 | ||
295 | if (k) { | |
fde25a9b AS |
296 | /* Drop reference added by kset_find_obj() */ |
297 | kobject_put(k); | |
e5dd1278 GKH |
298 | priv = to_driver(k); |
299 | return priv->driver; | |
300 | } | |
1da177e4 LT |
301 | return NULL; |
302 | } | |
1da177e4 | 303 | EXPORT_SYMBOL_GPL(driver_find); |