]>
Commit | Line | Data |
---|---|---|
1 | // SPDX-License-Identifier: GPL-2.0 | |
2 | /* | |
3 | * bus.c - bus 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/async.h> | |
12 | #include <linux/device.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/errno.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/string.h> | |
18 | #include <linux/mutex.h> | |
19 | #include <linux/sysfs.h> | |
20 | #include "base.h" | |
21 | #include "power/power.h" | |
22 | ||
23 | /* /sys/devices/system */ | |
24 | static struct kset *system_kset; | |
25 | ||
26 | #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr) | |
27 | ||
28 | /* | |
29 | * sysfs bindings for drivers | |
30 | */ | |
31 | ||
32 | #define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr) | |
33 | ||
34 | #define DRIVER_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \ | |
35 | struct driver_attribute driver_attr_##_name = \ | |
36 | __ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) | |
37 | ||
38 | static int __must_check bus_rescan_devices_helper(struct device *dev, | |
39 | void *data); | |
40 | ||
41 | static struct bus_type *bus_get(struct bus_type *bus) | |
42 | { | |
43 | if (bus) { | |
44 | kset_get(&bus->p->subsys); | |
45 | return bus; | |
46 | } | |
47 | return NULL; | |
48 | } | |
49 | ||
50 | static void bus_put(struct bus_type *bus) | |
51 | { | |
52 | if (bus) | |
53 | kset_put(&bus->p->subsys); | |
54 | } | |
55 | ||
56 | static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr, | |
57 | char *buf) | |
58 | { | |
59 | struct driver_attribute *drv_attr = to_drv_attr(attr); | |
60 | struct driver_private *drv_priv = to_driver(kobj); | |
61 | ssize_t ret = -EIO; | |
62 | ||
63 | if (drv_attr->show) | |
64 | ret = drv_attr->show(drv_priv->driver, buf); | |
65 | return ret; | |
66 | } | |
67 | ||
68 | static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr, | |
69 | const char *buf, size_t count) | |
70 | { | |
71 | struct driver_attribute *drv_attr = to_drv_attr(attr); | |
72 | struct driver_private *drv_priv = to_driver(kobj); | |
73 | ssize_t ret = -EIO; | |
74 | ||
75 | if (drv_attr->store) | |
76 | ret = drv_attr->store(drv_priv->driver, buf, count); | |
77 | return ret; | |
78 | } | |
79 | ||
80 | static const struct sysfs_ops driver_sysfs_ops = { | |
81 | .show = drv_attr_show, | |
82 | .store = drv_attr_store, | |
83 | }; | |
84 | ||
85 | static void driver_release(struct kobject *kobj) | |
86 | { | |
87 | struct driver_private *drv_priv = to_driver(kobj); | |
88 | ||
89 | pr_debug("driver: '%s': %s\n", kobject_name(kobj), __func__); | |
90 | kfree(drv_priv); | |
91 | } | |
92 | ||
93 | static struct kobj_type driver_ktype = { | |
94 | .sysfs_ops = &driver_sysfs_ops, | |
95 | .release = driver_release, | |
96 | }; | |
97 | ||
98 | /* | |
99 | * sysfs bindings for buses | |
100 | */ | |
101 | static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr, | |
102 | char *buf) | |
103 | { | |
104 | struct bus_attribute *bus_attr = to_bus_attr(attr); | |
105 | struct subsys_private *subsys_priv = to_subsys_private(kobj); | |
106 | ssize_t ret = 0; | |
107 | ||
108 | if (bus_attr->show) | |
109 | ret = bus_attr->show(subsys_priv->bus, buf); | |
110 | return ret; | |
111 | } | |
112 | ||
113 | static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr, | |
114 | const char *buf, size_t count) | |
115 | { | |
116 | struct bus_attribute *bus_attr = to_bus_attr(attr); | |
117 | struct subsys_private *subsys_priv = to_subsys_private(kobj); | |
118 | ssize_t ret = 0; | |
119 | ||
120 | if (bus_attr->store) | |
121 | ret = bus_attr->store(subsys_priv->bus, buf, count); | |
122 | return ret; | |
123 | } | |
124 | ||
125 | static const struct sysfs_ops bus_sysfs_ops = { | |
126 | .show = bus_attr_show, | |
127 | .store = bus_attr_store, | |
128 | }; | |
129 | ||
130 | int bus_create_file(struct bus_type *bus, struct bus_attribute *attr) | |
131 | { | |
132 | int error; | |
133 | if (bus_get(bus)) { | |
134 | error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr); | |
135 | bus_put(bus); | |
136 | } else | |
137 | error = -EINVAL; | |
138 | return error; | |
139 | } | |
140 | EXPORT_SYMBOL_GPL(bus_create_file); | |
141 | ||
142 | void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr) | |
143 | { | |
144 | if (bus_get(bus)) { | |
145 | sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr); | |
146 | bus_put(bus); | |
147 | } | |
148 | } | |
149 | EXPORT_SYMBOL_GPL(bus_remove_file); | |
150 | ||
151 | static void bus_release(struct kobject *kobj) | |
152 | { | |
153 | struct subsys_private *priv = to_subsys_private(kobj); | |
154 | struct bus_type *bus = priv->bus; | |
155 | ||
156 | kfree(priv); | |
157 | bus->p = NULL; | |
158 | } | |
159 | ||
160 | static struct kobj_type bus_ktype = { | |
161 | .sysfs_ops = &bus_sysfs_ops, | |
162 | .release = bus_release, | |
163 | }; | |
164 | ||
165 | static int bus_uevent_filter(struct kset *kset, struct kobject *kobj) | |
166 | { | |
167 | struct kobj_type *ktype = get_ktype(kobj); | |
168 | ||
169 | if (ktype == &bus_ktype) | |
170 | return 1; | |
171 | return 0; | |
172 | } | |
173 | ||
174 | static const struct kset_uevent_ops bus_uevent_ops = { | |
175 | .filter = bus_uevent_filter, | |
176 | }; | |
177 | ||
178 | static struct kset *bus_kset; | |
179 | ||
180 | /* Manually detach a device from its associated driver. */ | |
181 | static ssize_t unbind_store(struct device_driver *drv, const char *buf, | |
182 | size_t count) | |
183 | { | |
184 | struct bus_type *bus = bus_get(drv->bus); | |
185 | struct device *dev; | |
186 | int err = -ENODEV; | |
187 | ||
188 | dev = bus_find_device_by_name(bus, NULL, buf); | |
189 | if (dev && dev->driver == drv) { | |
190 | device_driver_detach(dev); | |
191 | err = count; | |
192 | } | |
193 | put_device(dev); | |
194 | bus_put(bus); | |
195 | return err; | |
196 | } | |
197 | static DRIVER_ATTR_IGNORE_LOCKDEP(unbind, S_IWUSR, NULL, unbind_store); | |
198 | ||
199 | /* | |
200 | * Manually attach a device to a driver. | |
201 | * Note: the driver must want to bind to the device, | |
202 | * it is not possible to override the driver's id table. | |
203 | */ | |
204 | static ssize_t bind_store(struct device_driver *drv, const char *buf, | |
205 | size_t count) | |
206 | { | |
207 | struct bus_type *bus = bus_get(drv->bus); | |
208 | struct device *dev; | |
209 | int err = -ENODEV; | |
210 | ||
211 | dev = bus_find_device_by_name(bus, NULL, buf); | |
212 | if (dev && dev->driver == NULL && driver_match_device(drv, dev)) { | |
213 | err = device_driver_attach(drv, dev); | |
214 | ||
215 | if (err > 0) { | |
216 | /* success */ | |
217 | err = count; | |
218 | } else if (err == 0) { | |
219 | /* driver didn't accept device */ | |
220 | err = -ENODEV; | |
221 | } | |
222 | } | |
223 | put_device(dev); | |
224 | bus_put(bus); | |
225 | return err; | |
226 | } | |
227 | static DRIVER_ATTR_IGNORE_LOCKDEP(bind, S_IWUSR, NULL, bind_store); | |
228 | ||
229 | static ssize_t drivers_autoprobe_show(struct bus_type *bus, char *buf) | |
230 | { | |
231 | return sprintf(buf, "%d\n", bus->p->drivers_autoprobe); | |
232 | } | |
233 | ||
234 | static ssize_t drivers_autoprobe_store(struct bus_type *bus, | |
235 | const char *buf, size_t count) | |
236 | { | |
237 | if (buf[0] == '0') | |
238 | bus->p->drivers_autoprobe = 0; | |
239 | else | |
240 | bus->p->drivers_autoprobe = 1; | |
241 | return count; | |
242 | } | |
243 | ||
244 | static ssize_t drivers_probe_store(struct bus_type *bus, | |
245 | const char *buf, size_t count) | |
246 | { | |
247 | struct device *dev; | |
248 | int err = -EINVAL; | |
249 | ||
250 | dev = bus_find_device_by_name(bus, NULL, buf); | |
251 | if (!dev) | |
252 | return -ENODEV; | |
253 | if (bus_rescan_devices_helper(dev, NULL) == 0) | |
254 | err = count; | |
255 | put_device(dev); | |
256 | return err; | |
257 | } | |
258 | ||
259 | static struct device *next_device(struct klist_iter *i) | |
260 | { | |
261 | struct klist_node *n = klist_next(i); | |
262 | struct device *dev = NULL; | |
263 | struct device_private *dev_prv; | |
264 | ||
265 | if (n) { | |
266 | dev_prv = to_device_private_bus(n); | |
267 | dev = dev_prv->device; | |
268 | } | |
269 | return dev; | |
270 | } | |
271 | ||
272 | /** | |
273 | * bus_for_each_dev - device iterator. | |
274 | * @bus: bus type. | |
275 | * @start: device to start iterating from. | |
276 | * @data: data for the callback. | |
277 | * @fn: function to be called for each device. | |
278 | * | |
279 | * Iterate over @bus's list of devices, and call @fn for each, | |
280 | * passing it @data. If @start is not NULL, we use that device to | |
281 | * begin iterating from. | |
282 | * | |
283 | * We check the return of @fn each time. If it returns anything | |
284 | * other than 0, we break out and return that value. | |
285 | * | |
286 | * NOTE: The device that returns a non-zero value is not retained | |
287 | * in any way, nor is its refcount incremented. If the caller needs | |
288 | * to retain this data, it should do so, and increment the reference | |
289 | * count in the supplied callback. | |
290 | */ | |
291 | int bus_for_each_dev(struct bus_type *bus, struct device *start, | |
292 | void *data, int (*fn)(struct device *, void *)) | |
293 | { | |
294 | struct klist_iter i; | |
295 | struct device *dev; | |
296 | int error = 0; | |
297 | ||
298 | if (!bus || !bus->p) | |
299 | return -EINVAL; | |
300 | ||
301 | klist_iter_init_node(&bus->p->klist_devices, &i, | |
302 | (start ? &start->p->knode_bus : NULL)); | |
303 | while (!error && (dev = next_device(&i))) | |
304 | error = fn(dev, data); | |
305 | klist_iter_exit(&i); | |
306 | return error; | |
307 | } | |
308 | EXPORT_SYMBOL_GPL(bus_for_each_dev); | |
309 | ||
310 | /** | |
311 | * bus_find_device - device iterator for locating a particular device. | |
312 | * @bus: bus type | |
313 | * @start: Device to begin with | |
314 | * @data: Data to pass to match function | |
315 | * @match: Callback function to check device | |
316 | * | |
317 | * This is similar to the bus_for_each_dev() function above, but it | |
318 | * returns a reference to a device that is 'found' for later use, as | |
319 | * determined by the @match callback. | |
320 | * | |
321 | * The callback should return 0 if the device doesn't match and non-zero | |
322 | * if it does. If the callback returns non-zero, this function will | |
323 | * return to the caller and not iterate over any more devices. | |
324 | */ | |
325 | struct device *bus_find_device(struct bus_type *bus, | |
326 | struct device *start, const void *data, | |
327 | int (*match)(struct device *dev, const void *data)) | |
328 | { | |
329 | struct klist_iter i; | |
330 | struct device *dev; | |
331 | ||
332 | if (!bus || !bus->p) | |
333 | return NULL; | |
334 | ||
335 | klist_iter_init_node(&bus->p->klist_devices, &i, | |
336 | (start ? &start->p->knode_bus : NULL)); | |
337 | while ((dev = next_device(&i))) | |
338 | if (match(dev, data) && get_device(dev)) | |
339 | break; | |
340 | klist_iter_exit(&i); | |
341 | return dev; | |
342 | } | |
343 | EXPORT_SYMBOL_GPL(bus_find_device); | |
344 | ||
345 | static int match_name(struct device *dev, const void *data) | |
346 | { | |
347 | const char *name = data; | |
348 | ||
349 | return sysfs_streq(name, dev_name(dev)); | |
350 | } | |
351 | ||
352 | /** | |
353 | * bus_find_device_by_name - device iterator for locating a particular device of a specific name | |
354 | * @bus: bus type | |
355 | * @start: Device to begin with | |
356 | * @name: name of the device to match | |
357 | * | |
358 | * This is similar to the bus_find_device() function above, but it handles | |
359 | * searching by a name automatically, no need to write another strcmp matching | |
360 | * function. | |
361 | */ | |
362 | struct device *bus_find_device_by_name(struct bus_type *bus, | |
363 | struct device *start, const char *name) | |
364 | { | |
365 | return bus_find_device(bus, start, (void *)name, match_name); | |
366 | } | |
367 | EXPORT_SYMBOL_GPL(bus_find_device_by_name); | |
368 | ||
369 | /** | |
370 | * subsys_find_device_by_id - find a device with a specific enumeration number | |
371 | * @subsys: subsystem | |
372 | * @id: index 'id' in struct device | |
373 | * @hint: device to check first | |
374 | * | |
375 | * Check the hint's next object and if it is a match return it directly, | |
376 | * otherwise, fall back to a full list search. Either way a reference for | |
377 | * the returned object is taken. | |
378 | */ | |
379 | struct device *subsys_find_device_by_id(struct bus_type *subsys, unsigned int id, | |
380 | struct device *hint) | |
381 | { | |
382 | struct klist_iter i; | |
383 | struct device *dev; | |
384 | ||
385 | if (!subsys) | |
386 | return NULL; | |
387 | ||
388 | if (hint) { | |
389 | klist_iter_init_node(&subsys->p->klist_devices, &i, &hint->p->knode_bus); | |
390 | dev = next_device(&i); | |
391 | if (dev && dev->id == id && get_device(dev)) { | |
392 | klist_iter_exit(&i); | |
393 | return dev; | |
394 | } | |
395 | klist_iter_exit(&i); | |
396 | } | |
397 | ||
398 | klist_iter_init_node(&subsys->p->klist_devices, &i, NULL); | |
399 | while ((dev = next_device(&i))) { | |
400 | if (dev->id == id && get_device(dev)) { | |
401 | klist_iter_exit(&i); | |
402 | return dev; | |
403 | } | |
404 | } | |
405 | klist_iter_exit(&i); | |
406 | return NULL; | |
407 | } | |
408 | EXPORT_SYMBOL_GPL(subsys_find_device_by_id); | |
409 | ||
410 | static struct device_driver *next_driver(struct klist_iter *i) | |
411 | { | |
412 | struct klist_node *n = klist_next(i); | |
413 | struct driver_private *drv_priv; | |
414 | ||
415 | if (n) { | |
416 | drv_priv = container_of(n, struct driver_private, knode_bus); | |
417 | return drv_priv->driver; | |
418 | } | |
419 | return NULL; | |
420 | } | |
421 | ||
422 | /** | |
423 | * bus_for_each_drv - driver iterator | |
424 | * @bus: bus we're dealing with. | |
425 | * @start: driver to start iterating on. | |
426 | * @data: data to pass to the callback. | |
427 | * @fn: function to call for each driver. | |
428 | * | |
429 | * This is nearly identical to the device iterator above. | |
430 | * We iterate over each driver that belongs to @bus, and call | |
431 | * @fn for each. If @fn returns anything but 0, we break out | |
432 | * and return it. If @start is not NULL, we use it as the head | |
433 | * of the list. | |
434 | * | |
435 | * NOTE: we don't return the driver that returns a non-zero | |
436 | * value, nor do we leave the reference count incremented for that | |
437 | * driver. If the caller needs to know that info, it must set it | |
438 | * in the callback. It must also be sure to increment the refcount | |
439 | * so it doesn't disappear before returning to the caller. | |
440 | */ | |
441 | int bus_for_each_drv(struct bus_type *bus, struct device_driver *start, | |
442 | void *data, int (*fn)(struct device_driver *, void *)) | |
443 | { | |
444 | struct klist_iter i; | |
445 | struct device_driver *drv; | |
446 | int error = 0; | |
447 | ||
448 | if (!bus) | |
449 | return -EINVAL; | |
450 | ||
451 | klist_iter_init_node(&bus->p->klist_drivers, &i, | |
452 | start ? &start->p->knode_bus : NULL); | |
453 | while ((drv = next_driver(&i)) && !error) | |
454 | error = fn(drv, data); | |
455 | klist_iter_exit(&i); | |
456 | return error; | |
457 | } | |
458 | EXPORT_SYMBOL_GPL(bus_for_each_drv); | |
459 | ||
460 | /** | |
461 | * bus_add_device - add device to bus | |
462 | * @dev: device being added | |
463 | * | |
464 | * - Add device's bus attributes. | |
465 | * - Create links to device's bus. | |
466 | * - Add the device to its bus's list of devices. | |
467 | */ | |
468 | int bus_add_device(struct device *dev) | |
469 | { | |
470 | struct bus_type *bus = bus_get(dev->bus); | |
471 | int error = 0; | |
472 | ||
473 | if (bus) { | |
474 | pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev)); | |
475 | error = device_add_groups(dev, bus->dev_groups); | |
476 | if (error) | |
477 | goto out_put; | |
478 | error = sysfs_create_link(&bus->p->devices_kset->kobj, | |
479 | &dev->kobj, dev_name(dev)); | |
480 | if (error) | |
481 | goto out_groups; | |
482 | error = sysfs_create_link(&dev->kobj, | |
483 | &dev->bus->p->subsys.kobj, "subsystem"); | |
484 | if (error) | |
485 | goto out_subsys; | |
486 | klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices); | |
487 | } | |
488 | return 0; | |
489 | ||
490 | out_subsys: | |
491 | sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev)); | |
492 | out_groups: | |
493 | device_remove_groups(dev, bus->dev_groups); | |
494 | out_put: | |
495 | bus_put(dev->bus); | |
496 | return error; | |
497 | } | |
498 | ||
499 | /** | |
500 | * bus_probe_device - probe drivers for a new device | |
501 | * @dev: device to probe | |
502 | * | |
503 | * - Automatically probe for a driver if the bus allows it. | |
504 | */ | |
505 | void bus_probe_device(struct device *dev) | |
506 | { | |
507 | struct bus_type *bus = dev->bus; | |
508 | struct subsys_interface *sif; | |
509 | ||
510 | if (!bus) | |
511 | return; | |
512 | ||
513 | if (bus->p->drivers_autoprobe) | |
514 | device_initial_probe(dev); | |
515 | ||
516 | mutex_lock(&bus->p->mutex); | |
517 | list_for_each_entry(sif, &bus->p->interfaces, node) | |
518 | if (sif->add_dev) | |
519 | sif->add_dev(dev, sif); | |
520 | mutex_unlock(&bus->p->mutex); | |
521 | } | |
522 | ||
523 | /** | |
524 | * bus_remove_device - remove device from bus | |
525 | * @dev: device to be removed | |
526 | * | |
527 | * - Remove device from all interfaces. | |
528 | * - Remove symlink from bus' directory. | |
529 | * - Delete device from bus's list. | |
530 | * - Detach from its driver. | |
531 | * - Drop reference taken in bus_add_device(). | |
532 | */ | |
533 | void bus_remove_device(struct device *dev) | |
534 | { | |
535 | struct bus_type *bus = dev->bus; | |
536 | struct subsys_interface *sif; | |
537 | ||
538 | if (!bus) | |
539 | return; | |
540 | ||
541 | mutex_lock(&bus->p->mutex); | |
542 | list_for_each_entry(sif, &bus->p->interfaces, node) | |
543 | if (sif->remove_dev) | |
544 | sif->remove_dev(dev, sif); | |
545 | mutex_unlock(&bus->p->mutex); | |
546 | ||
547 | sysfs_remove_link(&dev->kobj, "subsystem"); | |
548 | sysfs_remove_link(&dev->bus->p->devices_kset->kobj, | |
549 | dev_name(dev)); | |
550 | device_remove_groups(dev, dev->bus->dev_groups); | |
551 | if (klist_node_attached(&dev->p->knode_bus)) | |
552 | klist_del(&dev->p->knode_bus); | |
553 | ||
554 | pr_debug("bus: '%s': remove device %s\n", | |
555 | dev->bus->name, dev_name(dev)); | |
556 | device_release_driver(dev); | |
557 | bus_put(dev->bus); | |
558 | } | |
559 | ||
560 | static int __must_check add_bind_files(struct device_driver *drv) | |
561 | { | |
562 | int ret; | |
563 | ||
564 | ret = driver_create_file(drv, &driver_attr_unbind); | |
565 | if (ret == 0) { | |
566 | ret = driver_create_file(drv, &driver_attr_bind); | |
567 | if (ret) | |
568 | driver_remove_file(drv, &driver_attr_unbind); | |
569 | } | |
570 | return ret; | |
571 | } | |
572 | ||
573 | static void remove_bind_files(struct device_driver *drv) | |
574 | { | |
575 | driver_remove_file(drv, &driver_attr_bind); | |
576 | driver_remove_file(drv, &driver_attr_unbind); | |
577 | } | |
578 | ||
579 | static BUS_ATTR_WO(drivers_probe); | |
580 | static BUS_ATTR_RW(drivers_autoprobe); | |
581 | ||
582 | static int add_probe_files(struct bus_type *bus) | |
583 | { | |
584 | int retval; | |
585 | ||
586 | retval = bus_create_file(bus, &bus_attr_drivers_probe); | |
587 | if (retval) | |
588 | goto out; | |
589 | ||
590 | retval = bus_create_file(bus, &bus_attr_drivers_autoprobe); | |
591 | if (retval) | |
592 | bus_remove_file(bus, &bus_attr_drivers_probe); | |
593 | out: | |
594 | return retval; | |
595 | } | |
596 | ||
597 | static void remove_probe_files(struct bus_type *bus) | |
598 | { | |
599 | bus_remove_file(bus, &bus_attr_drivers_autoprobe); | |
600 | bus_remove_file(bus, &bus_attr_drivers_probe); | |
601 | } | |
602 | ||
603 | static ssize_t uevent_store(struct device_driver *drv, const char *buf, | |
604 | size_t count) | |
605 | { | |
606 | int rc; | |
607 | ||
608 | rc = kobject_synth_uevent(&drv->p->kobj, buf, count); | |
609 | return rc ? rc : count; | |
610 | } | |
611 | static DRIVER_ATTR_WO(uevent); | |
612 | ||
613 | /** | |
614 | * bus_add_driver - Add a driver to the bus. | |
615 | * @drv: driver. | |
616 | */ | |
617 | int bus_add_driver(struct device_driver *drv) | |
618 | { | |
619 | struct bus_type *bus; | |
620 | struct driver_private *priv; | |
621 | int error = 0; | |
622 | ||
623 | bus = bus_get(drv->bus); | |
624 | if (!bus) | |
625 | return -EINVAL; | |
626 | ||
627 | pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name); | |
628 | ||
629 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
630 | if (!priv) { | |
631 | error = -ENOMEM; | |
632 | goto out_put_bus; | |
633 | } | |
634 | klist_init(&priv->klist_devices, NULL, NULL); | |
635 | priv->driver = drv; | |
636 | drv->p = priv; | |
637 | priv->kobj.kset = bus->p->drivers_kset; | |
638 | error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL, | |
639 | "%s", drv->name); | |
640 | if (error) | |
641 | goto out_unregister; | |
642 | ||
643 | klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers); | |
644 | if (drv->bus->p->drivers_autoprobe) { | |
645 | error = driver_attach(drv); | |
646 | if (error) | |
647 | goto out_unregister; | |
648 | } | |
649 | module_add_driver(drv->owner, drv); | |
650 | ||
651 | error = driver_create_file(drv, &driver_attr_uevent); | |
652 | if (error) { | |
653 | printk(KERN_ERR "%s: uevent attr (%s) failed\n", | |
654 | __func__, drv->name); | |
655 | } | |
656 | error = driver_add_groups(drv, bus->drv_groups); | |
657 | if (error) { | |
658 | /* How the hell do we get out of this pickle? Give up */ | |
659 | printk(KERN_ERR "%s: driver_create_groups(%s) failed\n", | |
660 | __func__, drv->name); | |
661 | } | |
662 | ||
663 | if (!drv->suppress_bind_attrs) { | |
664 | error = add_bind_files(drv); | |
665 | if (error) { | |
666 | /* Ditto */ | |
667 | printk(KERN_ERR "%s: add_bind_files(%s) failed\n", | |
668 | __func__, drv->name); | |
669 | } | |
670 | } | |
671 | ||
672 | return 0; | |
673 | ||
674 | out_unregister: | |
675 | kobject_put(&priv->kobj); | |
676 | /* drv->p is freed in driver_release() */ | |
677 | drv->p = NULL; | |
678 | out_put_bus: | |
679 | bus_put(bus); | |
680 | return error; | |
681 | } | |
682 | ||
683 | /** | |
684 | * bus_remove_driver - delete driver from bus's knowledge. | |
685 | * @drv: driver. | |
686 | * | |
687 | * Detach the driver from the devices it controls, and remove | |
688 | * it from its bus's list of drivers. Finally, we drop the reference | |
689 | * to the bus we took in bus_add_driver(). | |
690 | */ | |
691 | void bus_remove_driver(struct device_driver *drv) | |
692 | { | |
693 | if (!drv->bus) | |
694 | return; | |
695 | ||
696 | if (!drv->suppress_bind_attrs) | |
697 | remove_bind_files(drv); | |
698 | driver_remove_groups(drv, drv->bus->drv_groups); | |
699 | driver_remove_file(drv, &driver_attr_uevent); | |
700 | klist_remove(&drv->p->knode_bus); | |
701 | pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name); | |
702 | driver_detach(drv); | |
703 | module_remove_driver(drv); | |
704 | kobject_put(&drv->p->kobj); | |
705 | bus_put(drv->bus); | |
706 | } | |
707 | ||
708 | /* Helper for bus_rescan_devices's iter */ | |
709 | static int __must_check bus_rescan_devices_helper(struct device *dev, | |
710 | void *data) | |
711 | { | |
712 | int ret = 0; | |
713 | ||
714 | if (!dev->driver) { | |
715 | if (dev->parent && dev->bus->need_parent_lock) | |
716 | device_lock(dev->parent); | |
717 | ret = device_attach(dev); | |
718 | if (dev->parent && dev->bus->need_parent_lock) | |
719 | device_unlock(dev->parent); | |
720 | } | |
721 | return ret < 0 ? ret : 0; | |
722 | } | |
723 | ||
724 | /** | |
725 | * bus_rescan_devices - rescan devices on the bus for possible drivers | |
726 | * @bus: the bus to scan. | |
727 | * | |
728 | * This function will look for devices on the bus with no driver | |
729 | * attached and rescan it against existing drivers to see if it matches | |
730 | * any by calling device_attach() for the unbound devices. | |
731 | */ | |
732 | int bus_rescan_devices(struct bus_type *bus) | |
733 | { | |
734 | return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper); | |
735 | } | |
736 | EXPORT_SYMBOL_GPL(bus_rescan_devices); | |
737 | ||
738 | /** | |
739 | * device_reprobe - remove driver for a device and probe for a new driver | |
740 | * @dev: the device to reprobe | |
741 | * | |
742 | * This function detaches the attached driver (if any) for the given | |
743 | * device and restarts the driver probing process. It is intended | |
744 | * to use if probing criteria changed during a devices lifetime and | |
745 | * driver attachment should change accordingly. | |
746 | */ | |
747 | int device_reprobe(struct device *dev) | |
748 | { | |
749 | if (dev->driver) | |
750 | device_driver_detach(dev); | |
751 | return bus_rescan_devices_helper(dev, NULL); | |
752 | } | |
753 | EXPORT_SYMBOL_GPL(device_reprobe); | |
754 | ||
755 | /** | |
756 | * find_bus - locate bus by name. | |
757 | * @name: name of bus. | |
758 | * | |
759 | * Call kset_find_obj() to iterate over list of buses to | |
760 | * find a bus by name. Return bus if found. | |
761 | * | |
762 | * Note that kset_find_obj increments bus' reference count. | |
763 | */ | |
764 | #if 0 | |
765 | struct bus_type *find_bus(char *name) | |
766 | { | |
767 | struct kobject *k = kset_find_obj(bus_kset, name); | |
768 | return k ? to_bus(k) : NULL; | |
769 | } | |
770 | #endif /* 0 */ | |
771 | ||
772 | static int bus_add_groups(struct bus_type *bus, | |
773 | const struct attribute_group **groups) | |
774 | { | |
775 | return sysfs_create_groups(&bus->p->subsys.kobj, groups); | |
776 | } | |
777 | ||
778 | static void bus_remove_groups(struct bus_type *bus, | |
779 | const struct attribute_group **groups) | |
780 | { | |
781 | sysfs_remove_groups(&bus->p->subsys.kobj, groups); | |
782 | } | |
783 | ||
784 | static void klist_devices_get(struct klist_node *n) | |
785 | { | |
786 | struct device_private *dev_prv = to_device_private_bus(n); | |
787 | struct device *dev = dev_prv->device; | |
788 | ||
789 | get_device(dev); | |
790 | } | |
791 | ||
792 | static void klist_devices_put(struct klist_node *n) | |
793 | { | |
794 | struct device_private *dev_prv = to_device_private_bus(n); | |
795 | struct device *dev = dev_prv->device; | |
796 | ||
797 | put_device(dev); | |
798 | } | |
799 | ||
800 | static ssize_t bus_uevent_store(struct bus_type *bus, | |
801 | const char *buf, size_t count) | |
802 | { | |
803 | int rc; | |
804 | ||
805 | rc = kobject_synth_uevent(&bus->p->subsys.kobj, buf, count); | |
806 | return rc ? rc : count; | |
807 | } | |
808 | /* | |
809 | * "open code" the old BUS_ATTR() macro here. We want to use BUS_ATTR_WO() | |
810 | * here, but can not use it as earlier in the file we have | |
811 | * DEVICE_ATTR_WO(uevent), which would cause a clash with the with the store | |
812 | * function name. | |
813 | */ | |
814 | static struct bus_attribute bus_attr_uevent = __ATTR(uevent, S_IWUSR, NULL, | |
815 | bus_uevent_store); | |
816 | ||
817 | /** | |
818 | * bus_register - register a driver-core subsystem | |
819 | * @bus: bus to register | |
820 | * | |
821 | * Once we have that, we register the bus with the kobject | |
822 | * infrastructure, then register the children subsystems it has: | |
823 | * the devices and drivers that belong to the subsystem. | |
824 | */ | |
825 | int bus_register(struct bus_type *bus) | |
826 | { | |
827 | int retval; | |
828 | struct subsys_private *priv; | |
829 | struct lock_class_key *key = &bus->lock_key; | |
830 | ||
831 | priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL); | |
832 | if (!priv) | |
833 | return -ENOMEM; | |
834 | ||
835 | priv->bus = bus; | |
836 | bus->p = priv; | |
837 | ||
838 | BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier); | |
839 | ||
840 | retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name); | |
841 | if (retval) | |
842 | goto out; | |
843 | ||
844 | priv->subsys.kobj.kset = bus_kset; | |
845 | priv->subsys.kobj.ktype = &bus_ktype; | |
846 | priv->drivers_autoprobe = 1; | |
847 | ||
848 | retval = kset_register(&priv->subsys); | |
849 | if (retval) | |
850 | goto out; | |
851 | ||
852 | retval = bus_create_file(bus, &bus_attr_uevent); | |
853 | if (retval) | |
854 | goto bus_uevent_fail; | |
855 | ||
856 | priv->devices_kset = kset_create_and_add("devices", NULL, | |
857 | &priv->subsys.kobj); | |
858 | if (!priv->devices_kset) { | |
859 | retval = -ENOMEM; | |
860 | goto bus_devices_fail; | |
861 | } | |
862 | ||
863 | priv->drivers_kset = kset_create_and_add("drivers", NULL, | |
864 | &priv->subsys.kobj); | |
865 | if (!priv->drivers_kset) { | |
866 | retval = -ENOMEM; | |
867 | goto bus_drivers_fail; | |
868 | } | |
869 | ||
870 | INIT_LIST_HEAD(&priv->interfaces); | |
871 | __mutex_init(&priv->mutex, "subsys mutex", key); | |
872 | klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put); | |
873 | klist_init(&priv->klist_drivers, NULL, NULL); | |
874 | ||
875 | retval = add_probe_files(bus); | |
876 | if (retval) | |
877 | goto bus_probe_files_fail; | |
878 | ||
879 | retval = bus_add_groups(bus, bus->bus_groups); | |
880 | if (retval) | |
881 | goto bus_groups_fail; | |
882 | ||
883 | pr_debug("bus: '%s': registered\n", bus->name); | |
884 | return 0; | |
885 | ||
886 | bus_groups_fail: | |
887 | remove_probe_files(bus); | |
888 | bus_probe_files_fail: | |
889 | kset_unregister(bus->p->drivers_kset); | |
890 | bus_drivers_fail: | |
891 | kset_unregister(bus->p->devices_kset); | |
892 | bus_devices_fail: | |
893 | bus_remove_file(bus, &bus_attr_uevent); | |
894 | bus_uevent_fail: | |
895 | kset_unregister(&bus->p->subsys); | |
896 | out: | |
897 | kfree(bus->p); | |
898 | bus->p = NULL; | |
899 | return retval; | |
900 | } | |
901 | EXPORT_SYMBOL_GPL(bus_register); | |
902 | ||
903 | /** | |
904 | * bus_unregister - remove a bus from the system | |
905 | * @bus: bus. | |
906 | * | |
907 | * Unregister the child subsystems and the bus itself. | |
908 | * Finally, we call bus_put() to release the refcount | |
909 | */ | |
910 | void bus_unregister(struct bus_type *bus) | |
911 | { | |
912 | pr_debug("bus: '%s': unregistering\n", bus->name); | |
913 | if (bus->dev_root) | |
914 | device_unregister(bus->dev_root); | |
915 | bus_remove_groups(bus, bus->bus_groups); | |
916 | remove_probe_files(bus); | |
917 | kset_unregister(bus->p->drivers_kset); | |
918 | kset_unregister(bus->p->devices_kset); | |
919 | bus_remove_file(bus, &bus_attr_uevent); | |
920 | kset_unregister(&bus->p->subsys); | |
921 | } | |
922 | EXPORT_SYMBOL_GPL(bus_unregister); | |
923 | ||
924 | int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb) | |
925 | { | |
926 | return blocking_notifier_chain_register(&bus->p->bus_notifier, nb); | |
927 | } | |
928 | EXPORT_SYMBOL_GPL(bus_register_notifier); | |
929 | ||
930 | int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb) | |
931 | { | |
932 | return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb); | |
933 | } | |
934 | EXPORT_SYMBOL_GPL(bus_unregister_notifier); | |
935 | ||
936 | struct kset *bus_get_kset(struct bus_type *bus) | |
937 | { | |
938 | return &bus->p->subsys; | |
939 | } | |
940 | EXPORT_SYMBOL_GPL(bus_get_kset); | |
941 | ||
942 | struct klist *bus_get_device_klist(struct bus_type *bus) | |
943 | { | |
944 | return &bus->p->klist_devices; | |
945 | } | |
946 | EXPORT_SYMBOL_GPL(bus_get_device_klist); | |
947 | ||
948 | /* | |
949 | * Yes, this forcibly breaks the klist abstraction temporarily. It | |
950 | * just wants to sort the klist, not change reference counts and | |
951 | * take/drop locks rapidly in the process. It does all this while | |
952 | * holding the lock for the list, so objects can't otherwise be | |
953 | * added/removed while we're swizzling. | |
954 | */ | |
955 | static void device_insertion_sort_klist(struct device *a, struct list_head *list, | |
956 | int (*compare)(const struct device *a, | |
957 | const struct device *b)) | |
958 | { | |
959 | struct klist_node *n; | |
960 | struct device_private *dev_prv; | |
961 | struct device *b; | |
962 | ||
963 | list_for_each_entry(n, list, n_node) { | |
964 | dev_prv = to_device_private_bus(n); | |
965 | b = dev_prv->device; | |
966 | if (compare(a, b) <= 0) { | |
967 | list_move_tail(&a->p->knode_bus.n_node, | |
968 | &b->p->knode_bus.n_node); | |
969 | return; | |
970 | } | |
971 | } | |
972 | list_move_tail(&a->p->knode_bus.n_node, list); | |
973 | } | |
974 | ||
975 | void bus_sort_breadthfirst(struct bus_type *bus, | |
976 | int (*compare)(const struct device *a, | |
977 | const struct device *b)) | |
978 | { | |
979 | LIST_HEAD(sorted_devices); | |
980 | struct klist_node *n, *tmp; | |
981 | struct device_private *dev_prv; | |
982 | struct device *dev; | |
983 | struct klist *device_klist; | |
984 | ||
985 | device_klist = bus_get_device_klist(bus); | |
986 | ||
987 | spin_lock(&device_klist->k_lock); | |
988 | list_for_each_entry_safe(n, tmp, &device_klist->k_list, n_node) { | |
989 | dev_prv = to_device_private_bus(n); | |
990 | dev = dev_prv->device; | |
991 | device_insertion_sort_klist(dev, &sorted_devices, compare); | |
992 | } | |
993 | list_splice(&sorted_devices, &device_klist->k_list); | |
994 | spin_unlock(&device_klist->k_lock); | |
995 | } | |
996 | EXPORT_SYMBOL_GPL(bus_sort_breadthfirst); | |
997 | ||
998 | /** | |
999 | * subsys_dev_iter_init - initialize subsys device iterator | |
1000 | * @iter: subsys iterator to initialize | |
1001 | * @subsys: the subsys we wanna iterate over | |
1002 | * @start: the device to start iterating from, if any | |
1003 | * @type: device_type of the devices to iterate over, NULL for all | |
1004 | * | |
1005 | * Initialize subsys iterator @iter such that it iterates over devices | |
1006 | * of @subsys. If @start is set, the list iteration will start there, | |
1007 | * otherwise if it is NULL, the iteration starts at the beginning of | |
1008 | * the list. | |
1009 | */ | |
1010 | void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct bus_type *subsys, | |
1011 | struct device *start, const struct device_type *type) | |
1012 | { | |
1013 | struct klist_node *start_knode = NULL; | |
1014 | ||
1015 | if (start) | |
1016 | start_knode = &start->p->knode_bus; | |
1017 | klist_iter_init_node(&subsys->p->klist_devices, &iter->ki, start_knode); | |
1018 | iter->type = type; | |
1019 | } | |
1020 | EXPORT_SYMBOL_GPL(subsys_dev_iter_init); | |
1021 | ||
1022 | /** | |
1023 | * subsys_dev_iter_next - iterate to the next device | |
1024 | * @iter: subsys iterator to proceed | |
1025 | * | |
1026 | * Proceed @iter to the next device and return it. Returns NULL if | |
1027 | * iteration is complete. | |
1028 | * | |
1029 | * The returned device is referenced and won't be released till | |
1030 | * iterator is proceed to the next device or exited. The caller is | |
1031 | * free to do whatever it wants to do with the device including | |
1032 | * calling back into subsys code. | |
1033 | */ | |
1034 | struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter) | |
1035 | { | |
1036 | struct klist_node *knode; | |
1037 | struct device *dev; | |
1038 | ||
1039 | for (;;) { | |
1040 | knode = klist_next(&iter->ki); | |
1041 | if (!knode) | |
1042 | return NULL; | |
1043 | dev = to_device_private_bus(knode)->device; | |
1044 | if (!iter->type || iter->type == dev->type) | |
1045 | return dev; | |
1046 | } | |
1047 | } | |
1048 | EXPORT_SYMBOL_GPL(subsys_dev_iter_next); | |
1049 | ||
1050 | /** | |
1051 | * subsys_dev_iter_exit - finish iteration | |
1052 | * @iter: subsys iterator to finish | |
1053 | * | |
1054 | * Finish an iteration. Always call this function after iteration is | |
1055 | * complete whether the iteration ran till the end or not. | |
1056 | */ | |
1057 | void subsys_dev_iter_exit(struct subsys_dev_iter *iter) | |
1058 | { | |
1059 | klist_iter_exit(&iter->ki); | |
1060 | } | |
1061 | EXPORT_SYMBOL_GPL(subsys_dev_iter_exit); | |
1062 | ||
1063 | int subsys_interface_register(struct subsys_interface *sif) | |
1064 | { | |
1065 | struct bus_type *subsys; | |
1066 | struct subsys_dev_iter iter; | |
1067 | struct device *dev; | |
1068 | ||
1069 | if (!sif || !sif->subsys) | |
1070 | return -ENODEV; | |
1071 | ||
1072 | subsys = bus_get(sif->subsys); | |
1073 | if (!subsys) | |
1074 | return -EINVAL; | |
1075 | ||
1076 | mutex_lock(&subsys->p->mutex); | |
1077 | list_add_tail(&sif->node, &subsys->p->interfaces); | |
1078 | if (sif->add_dev) { | |
1079 | subsys_dev_iter_init(&iter, subsys, NULL, NULL); | |
1080 | while ((dev = subsys_dev_iter_next(&iter))) | |
1081 | sif->add_dev(dev, sif); | |
1082 | subsys_dev_iter_exit(&iter); | |
1083 | } | |
1084 | mutex_unlock(&subsys->p->mutex); | |
1085 | ||
1086 | return 0; | |
1087 | } | |
1088 | EXPORT_SYMBOL_GPL(subsys_interface_register); | |
1089 | ||
1090 | void subsys_interface_unregister(struct subsys_interface *sif) | |
1091 | { | |
1092 | struct bus_type *subsys; | |
1093 | struct subsys_dev_iter iter; | |
1094 | struct device *dev; | |
1095 | ||
1096 | if (!sif || !sif->subsys) | |
1097 | return; | |
1098 | ||
1099 | subsys = sif->subsys; | |
1100 | ||
1101 | mutex_lock(&subsys->p->mutex); | |
1102 | list_del_init(&sif->node); | |
1103 | if (sif->remove_dev) { | |
1104 | subsys_dev_iter_init(&iter, subsys, NULL, NULL); | |
1105 | while ((dev = subsys_dev_iter_next(&iter))) | |
1106 | sif->remove_dev(dev, sif); | |
1107 | subsys_dev_iter_exit(&iter); | |
1108 | } | |
1109 | mutex_unlock(&subsys->p->mutex); | |
1110 | ||
1111 | bus_put(subsys); | |
1112 | } | |
1113 | EXPORT_SYMBOL_GPL(subsys_interface_unregister); | |
1114 | ||
1115 | static void system_root_device_release(struct device *dev) | |
1116 | { | |
1117 | kfree(dev); | |
1118 | } | |
1119 | ||
1120 | static int subsys_register(struct bus_type *subsys, | |
1121 | const struct attribute_group **groups, | |
1122 | struct kobject *parent_of_root) | |
1123 | { | |
1124 | struct device *dev; | |
1125 | int err; | |
1126 | ||
1127 | err = bus_register(subsys); | |
1128 | if (err < 0) | |
1129 | return err; | |
1130 | ||
1131 | dev = kzalloc(sizeof(struct device), GFP_KERNEL); | |
1132 | if (!dev) { | |
1133 | err = -ENOMEM; | |
1134 | goto err_dev; | |
1135 | } | |
1136 | ||
1137 | err = dev_set_name(dev, "%s", subsys->name); | |
1138 | if (err < 0) | |
1139 | goto err_name; | |
1140 | ||
1141 | dev->kobj.parent = parent_of_root; | |
1142 | dev->groups = groups; | |
1143 | dev->release = system_root_device_release; | |
1144 | ||
1145 | err = device_register(dev); | |
1146 | if (err < 0) | |
1147 | goto err_dev_reg; | |
1148 | ||
1149 | subsys->dev_root = dev; | |
1150 | return 0; | |
1151 | ||
1152 | err_dev_reg: | |
1153 | put_device(dev); | |
1154 | dev = NULL; | |
1155 | err_name: | |
1156 | kfree(dev); | |
1157 | err_dev: | |
1158 | bus_unregister(subsys); | |
1159 | return err; | |
1160 | } | |
1161 | ||
1162 | /** | |
1163 | * subsys_system_register - register a subsystem at /sys/devices/system/ | |
1164 | * @subsys: system subsystem | |
1165 | * @groups: default attributes for the root device | |
1166 | * | |
1167 | * All 'system' subsystems have a /sys/devices/system/<name> root device | |
1168 | * with the name of the subsystem. The root device can carry subsystem- | |
1169 | * wide attributes. All registered devices are below this single root | |
1170 | * device and are named after the subsystem with a simple enumeration | |
1171 | * number appended. The registered devices are not explicitly named; | |
1172 | * only 'id' in the device needs to be set. | |
1173 | * | |
1174 | * Do not use this interface for anything new, it exists for compatibility | |
1175 | * with bad ideas only. New subsystems should use plain subsystems; and | |
1176 | * add the subsystem-wide attributes should be added to the subsystem | |
1177 | * directory itself and not some create fake root-device placed in | |
1178 | * /sys/devices/system/<name>. | |
1179 | */ | |
1180 | int subsys_system_register(struct bus_type *subsys, | |
1181 | const struct attribute_group **groups) | |
1182 | { | |
1183 | return subsys_register(subsys, groups, &system_kset->kobj); | |
1184 | } | |
1185 | EXPORT_SYMBOL_GPL(subsys_system_register); | |
1186 | ||
1187 | /** | |
1188 | * subsys_virtual_register - register a subsystem at /sys/devices/virtual/ | |
1189 | * @subsys: virtual subsystem | |
1190 | * @groups: default attributes for the root device | |
1191 | * | |
1192 | * All 'virtual' subsystems have a /sys/devices/system/<name> root device | |
1193 | * with the name of the subystem. The root device can carry subsystem-wide | |
1194 | * attributes. All registered devices are below this single root device. | |
1195 | * There's no restriction on device naming. This is for kernel software | |
1196 | * constructs which need sysfs interface. | |
1197 | */ | |
1198 | int subsys_virtual_register(struct bus_type *subsys, | |
1199 | const struct attribute_group **groups) | |
1200 | { | |
1201 | struct kobject *virtual_dir; | |
1202 | ||
1203 | virtual_dir = virtual_device_parent(NULL); | |
1204 | if (!virtual_dir) | |
1205 | return -ENOMEM; | |
1206 | ||
1207 | return subsys_register(subsys, groups, virtual_dir); | |
1208 | } | |
1209 | EXPORT_SYMBOL_GPL(subsys_virtual_register); | |
1210 | ||
1211 | int __init buses_init(void) | |
1212 | { | |
1213 | bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL); | |
1214 | if (!bus_kset) | |
1215 | return -ENOMEM; | |
1216 | ||
1217 | system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj); | |
1218 | if (!system_kset) | |
1219 | return -ENOMEM; | |
1220 | ||
1221 | return 0; | |
1222 | } |