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 | * Copyright (c) 2023 Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
10 | */ |
11 | |
12 | #include <linux/async.h> |
13 | #include <linux/device/bus.h> |
14 | #include <linux/device.h> |
15 | #include <linux/module.h> |
16 | #include <linux/errno.h> |
17 | #include <linux/slab.h> |
18 | #include <linux/init.h> |
19 | #include <linux/string.h> |
20 | #include <linux/mutex.h> |
21 | #include <linux/sysfs.h> |
22 | #include "base.h" |
23 | #include "power/power.h" |
24 | |
25 | /* /sys/devices/system */ |
26 | static struct kset *system_kset; |
27 | |
28 | /* /sys/bus */ |
29 | static struct kset *bus_kset; |
30 | |
31 | #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr) |
32 | |
33 | /* |
34 | * sysfs bindings for drivers |
35 | */ |
36 | |
37 | #define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr) |
38 | |
39 | #define DRIVER_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \ |
40 | struct driver_attribute driver_attr_##_name = \ |
41 | __ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) |
42 | |
43 | static int __must_check bus_rescan_devices_helper(struct device *dev, |
44 | void *data); |
45 | |
46 | /** |
47 | * bus_to_subsys - Turn a struct bus_type into a struct subsys_private |
48 | * |
49 | * @bus: pointer to the struct bus_type to look up |
50 | * |
51 | * The driver core internals needs to work on the subsys_private structure, not |
52 | * the external struct bus_type pointer. This function walks the list of |
53 | * registered busses in the system and finds the matching one and returns the |
54 | * internal struct subsys_private that relates to that bus. |
55 | * |
56 | * Note, the reference count of the return value is INCREMENTED if it is not |
57 | * NULL. A call to subsys_put() must be done when finished with the pointer in |
58 | * order for it to be properly freed. |
59 | */ |
60 | static struct subsys_private *bus_to_subsys(const struct bus_type *bus) |
61 | { |
62 | struct subsys_private *sp = NULL; |
63 | struct kobject *kobj; |
64 | |
65 | if (!bus || !bus_kset) |
66 | return NULL; |
67 | |
68 | spin_lock(lock: &bus_kset->list_lock); |
69 | |
70 | if (list_empty(head: &bus_kset->list)) |
71 | goto done; |
72 | |
73 | list_for_each_entry(kobj, &bus_kset->list, entry) { |
74 | struct kset *kset = container_of(kobj, struct kset, kobj); |
75 | |
76 | sp = container_of_const(kset, struct subsys_private, subsys); |
77 | if (sp->bus == bus) |
78 | goto done; |
79 | } |
80 | sp = NULL; |
81 | done: |
82 | sp = subsys_get(sp); |
83 | spin_unlock(lock: &bus_kset->list_lock); |
84 | return sp; |
85 | } |
86 | |
87 | static const struct bus_type *bus_get(const struct bus_type *bus) |
88 | { |
89 | struct subsys_private *sp = bus_to_subsys(bus); |
90 | |
91 | if (sp) |
92 | return bus; |
93 | return NULL; |
94 | } |
95 | |
96 | static void bus_put(const struct bus_type *bus) |
97 | { |
98 | struct subsys_private *sp = bus_to_subsys(bus); |
99 | |
100 | /* two puts are required as the call to bus_to_subsys incremented it again */ |
101 | subsys_put(sp); |
102 | subsys_put(sp); |
103 | } |
104 | |
105 | static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr, |
106 | char *buf) |
107 | { |
108 | struct driver_attribute *drv_attr = to_drv_attr(attr); |
109 | struct driver_private *drv_priv = to_driver(kobj); |
110 | ssize_t ret = -EIO; |
111 | |
112 | if (drv_attr->show) |
113 | ret = drv_attr->show(drv_priv->driver, buf); |
114 | return ret; |
115 | } |
116 | |
117 | static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr, |
118 | const char *buf, size_t count) |
119 | { |
120 | struct driver_attribute *drv_attr = to_drv_attr(attr); |
121 | struct driver_private *drv_priv = to_driver(kobj); |
122 | ssize_t ret = -EIO; |
123 | |
124 | if (drv_attr->store) |
125 | ret = drv_attr->store(drv_priv->driver, buf, count); |
126 | return ret; |
127 | } |
128 | |
129 | static const struct sysfs_ops driver_sysfs_ops = { |
130 | .show = drv_attr_show, |
131 | .store = drv_attr_store, |
132 | }; |
133 | |
134 | static void driver_release(struct kobject *kobj) |
135 | { |
136 | struct driver_private *drv_priv = to_driver(kobj); |
137 | |
138 | pr_debug("driver: '%s': %s\n" , kobject_name(kobj), __func__); |
139 | kfree(objp: drv_priv); |
140 | } |
141 | |
142 | static const struct kobj_type driver_ktype = { |
143 | .sysfs_ops = &driver_sysfs_ops, |
144 | .release = driver_release, |
145 | }; |
146 | |
147 | /* |
148 | * sysfs bindings for buses |
149 | */ |
150 | static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr, |
151 | char *buf) |
152 | { |
153 | struct bus_attribute *bus_attr = to_bus_attr(attr); |
154 | struct subsys_private *subsys_priv = to_subsys_private(kobj); |
155 | ssize_t ret = 0; |
156 | |
157 | if (bus_attr->show) |
158 | ret = bus_attr->show(subsys_priv->bus, buf); |
159 | return ret; |
160 | } |
161 | |
162 | static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr, |
163 | const char *buf, size_t count) |
164 | { |
165 | struct bus_attribute *bus_attr = to_bus_attr(attr); |
166 | struct subsys_private *subsys_priv = to_subsys_private(kobj); |
167 | ssize_t ret = 0; |
168 | |
169 | if (bus_attr->store) |
170 | ret = bus_attr->store(subsys_priv->bus, buf, count); |
171 | return ret; |
172 | } |
173 | |
174 | static const struct sysfs_ops bus_sysfs_ops = { |
175 | .show = bus_attr_show, |
176 | .store = bus_attr_store, |
177 | }; |
178 | |
179 | int bus_create_file(const struct bus_type *bus, struct bus_attribute *attr) |
180 | { |
181 | struct subsys_private *sp = bus_to_subsys(bus); |
182 | int error; |
183 | |
184 | if (!sp) |
185 | return -EINVAL; |
186 | |
187 | error = sysfs_create_file(kobj: &sp->subsys.kobj, attr: &attr->attr); |
188 | |
189 | subsys_put(sp); |
190 | return error; |
191 | } |
192 | EXPORT_SYMBOL_GPL(bus_create_file); |
193 | |
194 | void bus_remove_file(const struct bus_type *bus, struct bus_attribute *attr) |
195 | { |
196 | struct subsys_private *sp = bus_to_subsys(bus); |
197 | |
198 | if (!sp) |
199 | return; |
200 | |
201 | sysfs_remove_file(kobj: &sp->subsys.kobj, attr: &attr->attr); |
202 | subsys_put(sp); |
203 | } |
204 | EXPORT_SYMBOL_GPL(bus_remove_file); |
205 | |
206 | static void bus_release(struct kobject *kobj) |
207 | { |
208 | struct subsys_private *priv = to_subsys_private(kobj); |
209 | |
210 | lockdep_unregister_key(key: &priv->lock_key); |
211 | kfree(objp: priv); |
212 | } |
213 | |
214 | static const struct kobj_type bus_ktype = { |
215 | .sysfs_ops = &bus_sysfs_ops, |
216 | .release = bus_release, |
217 | }; |
218 | |
219 | static int bus_uevent_filter(const struct kobject *kobj) |
220 | { |
221 | const struct kobj_type *ktype = get_ktype(kobj); |
222 | |
223 | if (ktype == &bus_ktype) |
224 | return 1; |
225 | return 0; |
226 | } |
227 | |
228 | static const struct kset_uevent_ops bus_uevent_ops = { |
229 | .filter = bus_uevent_filter, |
230 | }; |
231 | |
232 | /* Manually detach a device from its associated driver. */ |
233 | static ssize_t unbind_store(struct device_driver *drv, const char *buf, |
234 | size_t count) |
235 | { |
236 | const struct bus_type *bus = bus_get(bus: drv->bus); |
237 | struct device *dev; |
238 | int err = -ENODEV; |
239 | |
240 | dev = bus_find_device_by_name(bus, NULL, name: buf); |
241 | if (dev && dev->driver == drv) { |
242 | device_driver_detach(dev); |
243 | err = count; |
244 | } |
245 | put_device(dev); |
246 | bus_put(bus); |
247 | return err; |
248 | } |
249 | static DRIVER_ATTR_IGNORE_LOCKDEP(unbind, 0200, NULL, unbind_store); |
250 | |
251 | /* |
252 | * Manually attach a device to a driver. |
253 | * Note: the driver must want to bind to the device, |
254 | * it is not possible to override the driver's id table. |
255 | */ |
256 | static ssize_t bind_store(struct device_driver *drv, const char *buf, |
257 | size_t count) |
258 | { |
259 | const struct bus_type *bus = bus_get(bus: drv->bus); |
260 | struct device *dev; |
261 | int err = -ENODEV; |
262 | |
263 | dev = bus_find_device_by_name(bus, NULL, name: buf); |
264 | if (dev && driver_match_device(drv, dev)) { |
265 | err = device_driver_attach(drv, dev); |
266 | if (!err) { |
267 | /* success */ |
268 | err = count; |
269 | } |
270 | } |
271 | put_device(dev); |
272 | bus_put(bus); |
273 | return err; |
274 | } |
275 | static DRIVER_ATTR_IGNORE_LOCKDEP(bind, 0200, NULL, bind_store); |
276 | |
277 | static ssize_t drivers_autoprobe_show(const struct bus_type *bus, char *buf) |
278 | { |
279 | struct subsys_private *sp = bus_to_subsys(bus); |
280 | int ret; |
281 | |
282 | if (!sp) |
283 | return -EINVAL; |
284 | |
285 | ret = sysfs_emit(buf, fmt: "%d\n" , sp->drivers_autoprobe); |
286 | subsys_put(sp); |
287 | return ret; |
288 | } |
289 | |
290 | static ssize_t drivers_autoprobe_store(const struct bus_type *bus, |
291 | const char *buf, size_t count) |
292 | { |
293 | struct subsys_private *sp = bus_to_subsys(bus); |
294 | |
295 | if (!sp) |
296 | return -EINVAL; |
297 | |
298 | if (buf[0] == '0') |
299 | sp->drivers_autoprobe = 0; |
300 | else |
301 | sp->drivers_autoprobe = 1; |
302 | |
303 | subsys_put(sp); |
304 | return count; |
305 | } |
306 | |
307 | static ssize_t drivers_probe_store(const struct bus_type *bus, |
308 | const char *buf, size_t count) |
309 | { |
310 | struct device *dev; |
311 | int err = -EINVAL; |
312 | |
313 | dev = bus_find_device_by_name(bus, NULL, name: buf); |
314 | if (!dev) |
315 | return -ENODEV; |
316 | if (bus_rescan_devices_helper(dev, NULL) == 0) |
317 | err = count; |
318 | put_device(dev); |
319 | return err; |
320 | } |
321 | |
322 | static struct device *next_device(struct klist_iter *i) |
323 | { |
324 | struct klist_node *n = klist_next(i); |
325 | struct device *dev = NULL; |
326 | struct device_private *dev_prv; |
327 | |
328 | if (n) { |
329 | dev_prv = to_device_private_bus(n); |
330 | dev = dev_prv->device; |
331 | } |
332 | return dev; |
333 | } |
334 | |
335 | /** |
336 | * bus_for_each_dev - device iterator. |
337 | * @bus: bus type. |
338 | * @start: device to start iterating from. |
339 | * @data: data for the callback. |
340 | * @fn: function to be called for each device. |
341 | * |
342 | * Iterate over @bus's list of devices, and call @fn for each, |
343 | * passing it @data. If @start is not NULL, we use that device to |
344 | * begin iterating from. |
345 | * |
346 | * We check the return of @fn each time. If it returns anything |
347 | * other than 0, we break out and return that value. |
348 | * |
349 | * NOTE: The device that returns a non-zero value is not retained |
350 | * in any way, nor is its refcount incremented. If the caller needs |
351 | * to retain this data, it should do so, and increment the reference |
352 | * count in the supplied callback. |
353 | */ |
354 | int bus_for_each_dev(const struct bus_type *bus, struct device *start, |
355 | void *data, int (*fn)(struct device *, void *)) |
356 | { |
357 | struct subsys_private *sp = bus_to_subsys(bus); |
358 | struct klist_iter i; |
359 | struct device *dev; |
360 | int error = 0; |
361 | |
362 | if (!sp) |
363 | return -EINVAL; |
364 | |
365 | klist_iter_init_node(k: &sp->klist_devices, i: &i, |
366 | n: (start ? &start->p->knode_bus : NULL)); |
367 | while (!error && (dev = next_device(i: &i))) |
368 | error = fn(dev, data); |
369 | klist_iter_exit(i: &i); |
370 | subsys_put(sp); |
371 | return error; |
372 | } |
373 | EXPORT_SYMBOL_GPL(bus_for_each_dev); |
374 | |
375 | /** |
376 | * bus_find_device - device iterator for locating a particular device. |
377 | * @bus: bus type |
378 | * @start: Device to begin with |
379 | * @data: Data to pass to match function |
380 | * @match: Callback function to check device |
381 | * |
382 | * This is similar to the bus_for_each_dev() function above, but it |
383 | * returns a reference to a device that is 'found' for later use, as |
384 | * determined by the @match callback. |
385 | * |
386 | * The callback should return 0 if the device doesn't match and non-zero |
387 | * if it does. If the callback returns non-zero, this function will |
388 | * return to the caller and not iterate over any more devices. |
389 | */ |
390 | struct device *bus_find_device(const struct bus_type *bus, |
391 | struct device *start, const void *data, |
392 | int (*match)(struct device *dev, const void *data)) |
393 | { |
394 | struct subsys_private *sp = bus_to_subsys(bus); |
395 | struct klist_iter i; |
396 | struct device *dev; |
397 | |
398 | if (!sp) |
399 | return NULL; |
400 | |
401 | klist_iter_init_node(k: &sp->klist_devices, i: &i, |
402 | n: (start ? &start->p->knode_bus : NULL)); |
403 | while ((dev = next_device(i: &i))) |
404 | if (match(dev, data) && get_device(dev)) |
405 | break; |
406 | klist_iter_exit(i: &i); |
407 | subsys_put(sp); |
408 | return dev; |
409 | } |
410 | EXPORT_SYMBOL_GPL(bus_find_device); |
411 | |
412 | static struct device_driver *next_driver(struct klist_iter *i) |
413 | { |
414 | struct klist_node *n = klist_next(i); |
415 | struct driver_private *drv_priv; |
416 | |
417 | if (n) { |
418 | drv_priv = container_of(n, struct driver_private, knode_bus); |
419 | return drv_priv->driver; |
420 | } |
421 | return NULL; |
422 | } |
423 | |
424 | /** |
425 | * bus_for_each_drv - driver iterator |
426 | * @bus: bus we're dealing with. |
427 | * @start: driver to start iterating on. |
428 | * @data: data to pass to the callback. |
429 | * @fn: function to call for each driver. |
430 | * |
431 | * This is nearly identical to the device iterator above. |
432 | * We iterate over each driver that belongs to @bus, and call |
433 | * @fn for each. If @fn returns anything but 0, we break out |
434 | * and return it. If @start is not NULL, we use it as the head |
435 | * of the list. |
436 | * |
437 | * NOTE: we don't return the driver that returns a non-zero |
438 | * value, nor do we leave the reference count incremented for that |
439 | * driver. If the caller needs to know that info, it must set it |
440 | * in the callback. It must also be sure to increment the refcount |
441 | * so it doesn't disappear before returning to the caller. |
442 | */ |
443 | int bus_for_each_drv(const struct bus_type *bus, struct device_driver *start, |
444 | void *data, int (*fn)(struct device_driver *, void *)) |
445 | { |
446 | struct subsys_private *sp = bus_to_subsys(bus); |
447 | struct klist_iter i; |
448 | struct device_driver *drv; |
449 | int error = 0; |
450 | |
451 | if (!sp) |
452 | return -EINVAL; |
453 | |
454 | klist_iter_init_node(k: &sp->klist_drivers, i: &i, |
455 | n: start ? &start->p->knode_bus : NULL); |
456 | while ((drv = next_driver(i: &i)) && !error) |
457 | error = fn(drv, data); |
458 | klist_iter_exit(i: &i); |
459 | subsys_put(sp); |
460 | return error; |
461 | } |
462 | EXPORT_SYMBOL_GPL(bus_for_each_drv); |
463 | |
464 | /** |
465 | * bus_add_device - add device to bus |
466 | * @dev: device being added |
467 | * |
468 | * - Add device's bus attributes. |
469 | * - Create links to device's bus. |
470 | * - Add the device to its bus's list of devices. |
471 | */ |
472 | int bus_add_device(struct device *dev) |
473 | { |
474 | struct subsys_private *sp = bus_to_subsys(bus: dev->bus); |
475 | int error; |
476 | |
477 | if (!sp) { |
478 | /* |
479 | * This is a normal operation for many devices that do not |
480 | * have a bus assigned to them, just say that all went |
481 | * well. |
482 | */ |
483 | return 0; |
484 | } |
485 | |
486 | /* |
487 | * Reference in sp is now incremented and will be dropped when |
488 | * the device is removed from the bus |
489 | */ |
490 | |
491 | pr_debug("bus: '%s': add device %s\n" , sp->bus->name, dev_name(dev)); |
492 | |
493 | error = device_add_groups(dev, groups: sp->bus->dev_groups); |
494 | if (error) |
495 | goto out_put; |
496 | |
497 | error = sysfs_create_link(kobj: &sp->devices_kset->kobj, target: &dev->kobj, name: dev_name(dev)); |
498 | if (error) |
499 | goto out_groups; |
500 | |
501 | error = sysfs_create_link(kobj: &dev->kobj, target: &sp->subsys.kobj, name: "subsystem" ); |
502 | if (error) |
503 | goto out_subsys; |
504 | |
505 | klist_add_tail(n: &dev->p->knode_bus, k: &sp->klist_devices); |
506 | return 0; |
507 | |
508 | out_subsys: |
509 | sysfs_remove_link(kobj: &sp->devices_kset->kobj, name: dev_name(dev)); |
510 | out_groups: |
511 | device_remove_groups(dev, groups: sp->bus->dev_groups); |
512 | out_put: |
513 | subsys_put(sp); |
514 | return error; |
515 | } |
516 | |
517 | /** |
518 | * bus_probe_device - probe drivers for a new device |
519 | * @dev: device to probe |
520 | * |
521 | * - Automatically probe for a driver if the bus allows it. |
522 | */ |
523 | void bus_probe_device(struct device *dev) |
524 | { |
525 | struct subsys_private *sp = bus_to_subsys(bus: dev->bus); |
526 | struct subsys_interface *sif; |
527 | |
528 | if (!sp) |
529 | return; |
530 | |
531 | if (sp->drivers_autoprobe) |
532 | device_initial_probe(dev); |
533 | |
534 | mutex_lock(&sp->mutex); |
535 | list_for_each_entry(sif, &sp->interfaces, node) |
536 | if (sif->add_dev) |
537 | sif->add_dev(dev, sif); |
538 | mutex_unlock(lock: &sp->mutex); |
539 | subsys_put(sp); |
540 | } |
541 | |
542 | /** |
543 | * bus_remove_device - remove device from bus |
544 | * @dev: device to be removed |
545 | * |
546 | * - Remove device from all interfaces. |
547 | * - Remove symlink from bus' directory. |
548 | * - Delete device from bus's list. |
549 | * - Detach from its driver. |
550 | * - Drop reference taken in bus_add_device(). |
551 | */ |
552 | void bus_remove_device(struct device *dev) |
553 | { |
554 | struct subsys_private *sp = bus_to_subsys(bus: dev->bus); |
555 | struct subsys_interface *sif; |
556 | |
557 | if (!sp) |
558 | return; |
559 | |
560 | mutex_lock(&sp->mutex); |
561 | list_for_each_entry(sif, &sp->interfaces, node) |
562 | if (sif->remove_dev) |
563 | sif->remove_dev(dev, sif); |
564 | mutex_unlock(lock: &sp->mutex); |
565 | |
566 | sysfs_remove_link(kobj: &dev->kobj, name: "subsystem" ); |
567 | sysfs_remove_link(kobj: &sp->devices_kset->kobj, name: dev_name(dev)); |
568 | device_remove_groups(dev, groups: dev->bus->dev_groups); |
569 | if (klist_node_attached(n: &dev->p->knode_bus)) |
570 | klist_del(n: &dev->p->knode_bus); |
571 | |
572 | pr_debug("bus: '%s': remove device %s\n" , |
573 | dev->bus->name, dev_name(dev)); |
574 | device_release_driver(dev); |
575 | |
576 | /* |
577 | * Decrement the reference count twice, once for the bus_to_subsys() |
578 | * call in the start of this function, and the second one from the |
579 | * reference increment in bus_add_device() |
580 | */ |
581 | subsys_put(sp); |
582 | subsys_put(sp); |
583 | } |
584 | |
585 | static int __must_check add_bind_files(struct device_driver *drv) |
586 | { |
587 | int ret; |
588 | |
589 | ret = driver_create_file(driver: drv, attr: &driver_attr_unbind); |
590 | if (ret == 0) { |
591 | ret = driver_create_file(driver: drv, attr: &driver_attr_bind); |
592 | if (ret) |
593 | driver_remove_file(driver: drv, attr: &driver_attr_unbind); |
594 | } |
595 | return ret; |
596 | } |
597 | |
598 | static void remove_bind_files(struct device_driver *drv) |
599 | { |
600 | driver_remove_file(driver: drv, attr: &driver_attr_bind); |
601 | driver_remove_file(driver: drv, attr: &driver_attr_unbind); |
602 | } |
603 | |
604 | static BUS_ATTR_WO(drivers_probe); |
605 | static BUS_ATTR_RW(drivers_autoprobe); |
606 | |
607 | static int add_probe_files(const struct bus_type *bus) |
608 | { |
609 | int retval; |
610 | |
611 | retval = bus_create_file(bus, &bus_attr_drivers_probe); |
612 | if (retval) |
613 | goto out; |
614 | |
615 | retval = bus_create_file(bus, &bus_attr_drivers_autoprobe); |
616 | if (retval) |
617 | bus_remove_file(bus, &bus_attr_drivers_probe); |
618 | out: |
619 | return retval; |
620 | } |
621 | |
622 | static void remove_probe_files(const struct bus_type *bus) |
623 | { |
624 | bus_remove_file(bus, &bus_attr_drivers_autoprobe); |
625 | bus_remove_file(bus, &bus_attr_drivers_probe); |
626 | } |
627 | |
628 | static ssize_t uevent_store(struct device_driver *drv, const char *buf, |
629 | size_t count) |
630 | { |
631 | int rc; |
632 | |
633 | rc = kobject_synth_uevent(kobj: &drv->p->kobj, buf, count); |
634 | return rc ? rc : count; |
635 | } |
636 | static DRIVER_ATTR_WO(uevent); |
637 | |
638 | /** |
639 | * bus_add_driver - Add a driver to the bus. |
640 | * @drv: driver. |
641 | */ |
642 | int bus_add_driver(struct device_driver *drv) |
643 | { |
644 | struct subsys_private *sp = bus_to_subsys(bus: drv->bus); |
645 | struct driver_private *priv; |
646 | int error = 0; |
647 | |
648 | if (!sp) |
649 | return -EINVAL; |
650 | |
651 | /* |
652 | * Reference in sp is now incremented and will be dropped when |
653 | * the driver is removed from the bus |
654 | */ |
655 | pr_debug("bus: '%s': add driver %s\n" , sp->bus->name, drv->name); |
656 | |
657 | priv = kzalloc(size: sizeof(*priv), GFP_KERNEL); |
658 | if (!priv) { |
659 | error = -ENOMEM; |
660 | goto out_put_bus; |
661 | } |
662 | klist_init(k: &priv->klist_devices, NULL, NULL); |
663 | priv->driver = drv; |
664 | drv->p = priv; |
665 | priv->kobj.kset = sp->drivers_kset; |
666 | error = kobject_init_and_add(kobj: &priv->kobj, ktype: &driver_ktype, NULL, |
667 | fmt: "%s" , drv->name); |
668 | if (error) |
669 | goto out_unregister; |
670 | |
671 | klist_add_tail(n: &priv->knode_bus, k: &sp->klist_drivers); |
672 | if (sp->drivers_autoprobe) { |
673 | error = driver_attach(drv); |
674 | if (error) |
675 | goto out_del_list; |
676 | } |
677 | module_add_driver(mod: drv->owner, drv); |
678 | |
679 | error = driver_create_file(driver: drv, attr: &driver_attr_uevent); |
680 | if (error) { |
681 | printk(KERN_ERR "%s: uevent attr (%s) failed\n" , |
682 | __func__, drv->name); |
683 | } |
684 | error = driver_add_groups(drv, groups: sp->bus->drv_groups); |
685 | if (error) { |
686 | /* How the hell do we get out of this pickle? Give up */ |
687 | printk(KERN_ERR "%s: driver_add_groups(%s) failed\n" , |
688 | __func__, drv->name); |
689 | } |
690 | |
691 | if (!drv->suppress_bind_attrs) { |
692 | error = add_bind_files(drv); |
693 | if (error) { |
694 | /* Ditto */ |
695 | printk(KERN_ERR "%s: add_bind_files(%s) failed\n" , |
696 | __func__, drv->name); |
697 | } |
698 | } |
699 | |
700 | return 0; |
701 | |
702 | out_del_list: |
703 | klist_del(n: &priv->knode_bus); |
704 | out_unregister: |
705 | kobject_put(kobj: &priv->kobj); |
706 | /* drv->p is freed in driver_release() */ |
707 | drv->p = NULL; |
708 | out_put_bus: |
709 | subsys_put(sp); |
710 | return error; |
711 | } |
712 | |
713 | /** |
714 | * bus_remove_driver - delete driver from bus's knowledge. |
715 | * @drv: driver. |
716 | * |
717 | * Detach the driver from the devices it controls, and remove |
718 | * it from its bus's list of drivers. Finally, we drop the reference |
719 | * to the bus we took in bus_add_driver(). |
720 | */ |
721 | void bus_remove_driver(struct device_driver *drv) |
722 | { |
723 | struct subsys_private *sp = bus_to_subsys(bus: drv->bus); |
724 | |
725 | if (!sp) |
726 | return; |
727 | |
728 | pr_debug("bus: '%s': remove driver %s\n" , sp->bus->name, drv->name); |
729 | |
730 | if (!drv->suppress_bind_attrs) |
731 | remove_bind_files(drv); |
732 | driver_remove_groups(drv, groups: sp->bus->drv_groups); |
733 | driver_remove_file(driver: drv, attr: &driver_attr_uevent); |
734 | klist_remove(n: &drv->p->knode_bus); |
735 | driver_detach(drv); |
736 | module_remove_driver(drv); |
737 | kobject_put(kobj: &drv->p->kobj); |
738 | |
739 | /* |
740 | * Decrement the reference count twice, once for the bus_to_subsys() |
741 | * call in the start of this function, and the second one from the |
742 | * reference increment in bus_add_driver() |
743 | */ |
744 | subsys_put(sp); |
745 | subsys_put(sp); |
746 | } |
747 | |
748 | /* Helper for bus_rescan_devices's iter */ |
749 | static int __must_check bus_rescan_devices_helper(struct device *dev, |
750 | void *data) |
751 | { |
752 | int ret = 0; |
753 | |
754 | if (!dev->driver) { |
755 | if (dev->parent && dev->bus->need_parent_lock) |
756 | device_lock(dev: dev->parent); |
757 | ret = device_attach(dev); |
758 | if (dev->parent && dev->bus->need_parent_lock) |
759 | device_unlock(dev: dev->parent); |
760 | } |
761 | return ret < 0 ? ret : 0; |
762 | } |
763 | |
764 | /** |
765 | * bus_rescan_devices - rescan devices on the bus for possible drivers |
766 | * @bus: the bus to scan. |
767 | * |
768 | * This function will look for devices on the bus with no driver |
769 | * attached and rescan it against existing drivers to see if it matches |
770 | * any by calling device_attach() for the unbound devices. |
771 | */ |
772 | int bus_rescan_devices(const struct bus_type *bus) |
773 | { |
774 | return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper); |
775 | } |
776 | EXPORT_SYMBOL_GPL(bus_rescan_devices); |
777 | |
778 | /** |
779 | * device_reprobe - remove driver for a device and probe for a new driver |
780 | * @dev: the device to reprobe |
781 | * |
782 | * This function detaches the attached driver (if any) for the given |
783 | * device and restarts the driver probing process. It is intended |
784 | * to use if probing criteria changed during a devices lifetime and |
785 | * driver attachment should change accordingly. |
786 | */ |
787 | int device_reprobe(struct device *dev) |
788 | { |
789 | if (dev->driver) |
790 | device_driver_detach(dev); |
791 | return bus_rescan_devices_helper(dev, NULL); |
792 | } |
793 | EXPORT_SYMBOL_GPL(device_reprobe); |
794 | |
795 | static void klist_devices_get(struct klist_node *n) |
796 | { |
797 | struct device_private *dev_prv = to_device_private_bus(n); |
798 | struct device *dev = dev_prv->device; |
799 | |
800 | get_device(dev); |
801 | } |
802 | |
803 | static void klist_devices_put(struct klist_node *n) |
804 | { |
805 | struct device_private *dev_prv = to_device_private_bus(n); |
806 | struct device *dev = dev_prv->device; |
807 | |
808 | put_device(dev); |
809 | } |
810 | |
811 | static ssize_t bus_uevent_store(const struct bus_type *bus, |
812 | const char *buf, size_t count) |
813 | { |
814 | struct subsys_private *sp = bus_to_subsys(bus); |
815 | int ret; |
816 | |
817 | if (!sp) |
818 | return -EINVAL; |
819 | |
820 | ret = kobject_synth_uevent(kobj: &sp->subsys.kobj, buf, count); |
821 | subsys_put(sp); |
822 | |
823 | if (ret) |
824 | return ret; |
825 | return count; |
826 | } |
827 | /* |
828 | * "open code" the old BUS_ATTR() macro here. We want to use BUS_ATTR_WO() |
829 | * here, but can not use it as earlier in the file we have |
830 | * DEVICE_ATTR_WO(uevent), which would cause a clash with the with the store |
831 | * function name. |
832 | */ |
833 | static struct bus_attribute bus_attr_uevent = __ATTR(uevent, 0200, NULL, |
834 | bus_uevent_store); |
835 | |
836 | /** |
837 | * bus_register - register a driver-core subsystem |
838 | * @bus: bus to register |
839 | * |
840 | * Once we have that, we register the bus with the kobject |
841 | * infrastructure, then register the children subsystems it has: |
842 | * the devices and drivers that belong to the subsystem. |
843 | */ |
844 | int bus_register(const struct bus_type *bus) |
845 | { |
846 | int retval; |
847 | struct subsys_private *priv; |
848 | struct kobject *bus_kobj; |
849 | struct lock_class_key *key; |
850 | |
851 | priv = kzalloc(size: sizeof(struct subsys_private), GFP_KERNEL); |
852 | if (!priv) |
853 | return -ENOMEM; |
854 | |
855 | priv->bus = bus; |
856 | |
857 | BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier); |
858 | |
859 | bus_kobj = &priv->subsys.kobj; |
860 | retval = kobject_set_name(kobj: bus_kobj, name: "%s" , bus->name); |
861 | if (retval) |
862 | goto out; |
863 | |
864 | bus_kobj->kset = bus_kset; |
865 | bus_kobj->ktype = &bus_ktype; |
866 | priv->drivers_autoprobe = 1; |
867 | |
868 | retval = kset_register(kset: &priv->subsys); |
869 | if (retval) |
870 | goto out; |
871 | |
872 | retval = bus_create_file(bus, &bus_attr_uevent); |
873 | if (retval) |
874 | goto bus_uevent_fail; |
875 | |
876 | priv->devices_kset = kset_create_and_add(name: "devices" , NULL, parent_kobj: bus_kobj); |
877 | if (!priv->devices_kset) { |
878 | retval = -ENOMEM; |
879 | goto bus_devices_fail; |
880 | } |
881 | |
882 | priv->drivers_kset = kset_create_and_add(name: "drivers" , NULL, parent_kobj: bus_kobj); |
883 | if (!priv->drivers_kset) { |
884 | retval = -ENOMEM; |
885 | goto bus_drivers_fail; |
886 | } |
887 | |
888 | INIT_LIST_HEAD(list: &priv->interfaces); |
889 | key = &priv->lock_key; |
890 | lockdep_register_key(key); |
891 | __mutex_init(lock: &priv->mutex, name: "subsys mutex" , key); |
892 | klist_init(k: &priv->klist_devices, get: klist_devices_get, put: klist_devices_put); |
893 | klist_init(k: &priv->klist_drivers, NULL, NULL); |
894 | |
895 | retval = add_probe_files(bus); |
896 | if (retval) |
897 | goto bus_probe_files_fail; |
898 | |
899 | retval = sysfs_create_groups(kobj: bus_kobj, groups: bus->bus_groups); |
900 | if (retval) |
901 | goto bus_groups_fail; |
902 | |
903 | pr_debug("bus: '%s': registered\n" , bus->name); |
904 | return 0; |
905 | |
906 | bus_groups_fail: |
907 | remove_probe_files(bus); |
908 | bus_probe_files_fail: |
909 | kset_unregister(kset: priv->drivers_kset); |
910 | bus_drivers_fail: |
911 | kset_unregister(kset: priv->devices_kset); |
912 | bus_devices_fail: |
913 | bus_remove_file(bus, &bus_attr_uevent); |
914 | bus_uevent_fail: |
915 | kset_unregister(kset: &priv->subsys); |
916 | out: |
917 | kfree(objp: priv); |
918 | return retval; |
919 | } |
920 | EXPORT_SYMBOL_GPL(bus_register); |
921 | |
922 | /** |
923 | * bus_unregister - remove a bus from the system |
924 | * @bus: bus. |
925 | * |
926 | * Unregister the child subsystems and the bus itself. |
927 | * Finally, we call bus_put() to release the refcount |
928 | */ |
929 | void bus_unregister(const struct bus_type *bus) |
930 | { |
931 | struct subsys_private *sp = bus_to_subsys(bus); |
932 | struct kobject *bus_kobj; |
933 | |
934 | if (!sp) |
935 | return; |
936 | |
937 | pr_debug("bus: '%s': unregistering\n" , bus->name); |
938 | if (sp->dev_root) |
939 | device_unregister(dev: sp->dev_root); |
940 | |
941 | bus_kobj = &sp->subsys.kobj; |
942 | sysfs_remove_groups(kobj: bus_kobj, groups: bus->bus_groups); |
943 | remove_probe_files(bus); |
944 | bus_remove_file(bus, &bus_attr_uevent); |
945 | |
946 | kset_unregister(kset: sp->drivers_kset); |
947 | kset_unregister(kset: sp->devices_kset); |
948 | kset_unregister(kset: &sp->subsys); |
949 | subsys_put(sp); |
950 | } |
951 | EXPORT_SYMBOL_GPL(bus_unregister); |
952 | |
953 | int bus_register_notifier(const struct bus_type *bus, struct notifier_block *nb) |
954 | { |
955 | struct subsys_private *sp = bus_to_subsys(bus); |
956 | int retval; |
957 | |
958 | if (!sp) |
959 | return -EINVAL; |
960 | |
961 | retval = blocking_notifier_chain_register(nh: &sp->bus_notifier, nb); |
962 | subsys_put(sp); |
963 | return retval; |
964 | } |
965 | EXPORT_SYMBOL_GPL(bus_register_notifier); |
966 | |
967 | int bus_unregister_notifier(const struct bus_type *bus, struct notifier_block *nb) |
968 | { |
969 | struct subsys_private *sp = bus_to_subsys(bus); |
970 | int retval; |
971 | |
972 | if (!sp) |
973 | return -EINVAL; |
974 | retval = blocking_notifier_chain_unregister(nh: &sp->bus_notifier, nb); |
975 | subsys_put(sp); |
976 | return retval; |
977 | } |
978 | EXPORT_SYMBOL_GPL(bus_unregister_notifier); |
979 | |
980 | void bus_notify(struct device *dev, enum bus_notifier_event value) |
981 | { |
982 | struct subsys_private *sp = bus_to_subsys(bus: dev->bus); |
983 | |
984 | if (!sp) |
985 | return; |
986 | |
987 | blocking_notifier_call_chain(nh: &sp->bus_notifier, val: value, v: dev); |
988 | subsys_put(sp); |
989 | } |
990 | |
991 | struct kset *bus_get_kset(const struct bus_type *bus) |
992 | { |
993 | struct subsys_private *sp = bus_to_subsys(bus); |
994 | struct kset *kset; |
995 | |
996 | if (!sp) |
997 | return NULL; |
998 | |
999 | kset = &sp->subsys; |
1000 | subsys_put(sp); |
1001 | |
1002 | return kset; |
1003 | } |
1004 | EXPORT_SYMBOL_GPL(bus_get_kset); |
1005 | |
1006 | /* |
1007 | * Yes, this forcibly breaks the klist abstraction temporarily. It |
1008 | * just wants to sort the klist, not change reference counts and |
1009 | * take/drop locks rapidly in the process. It does all this while |
1010 | * holding the lock for the list, so objects can't otherwise be |
1011 | * added/removed while we're swizzling. |
1012 | */ |
1013 | static void device_insertion_sort_klist(struct device *a, struct list_head *list, |
1014 | int (*compare)(const struct device *a, |
1015 | const struct device *b)) |
1016 | { |
1017 | struct klist_node *n; |
1018 | struct device_private *dev_prv; |
1019 | struct device *b; |
1020 | |
1021 | list_for_each_entry(n, list, n_node) { |
1022 | dev_prv = to_device_private_bus(n); |
1023 | b = dev_prv->device; |
1024 | if (compare(a, b) <= 0) { |
1025 | list_move_tail(list: &a->p->knode_bus.n_node, |
1026 | head: &b->p->knode_bus.n_node); |
1027 | return; |
1028 | } |
1029 | } |
1030 | list_move_tail(list: &a->p->knode_bus.n_node, head: list); |
1031 | } |
1032 | |
1033 | void bus_sort_breadthfirst(struct bus_type *bus, |
1034 | int (*compare)(const struct device *a, |
1035 | const struct device *b)) |
1036 | { |
1037 | struct subsys_private *sp = bus_to_subsys(bus); |
1038 | LIST_HEAD(sorted_devices); |
1039 | struct klist_node *n, *tmp; |
1040 | struct device_private *dev_prv; |
1041 | struct device *dev; |
1042 | struct klist *device_klist; |
1043 | |
1044 | if (!sp) |
1045 | return; |
1046 | device_klist = &sp->klist_devices; |
1047 | |
1048 | spin_lock(lock: &device_klist->k_lock); |
1049 | list_for_each_entry_safe(n, tmp, &device_klist->k_list, n_node) { |
1050 | dev_prv = to_device_private_bus(n); |
1051 | dev = dev_prv->device; |
1052 | device_insertion_sort_klist(a: dev, list: &sorted_devices, compare); |
1053 | } |
1054 | list_splice(list: &sorted_devices, head: &device_klist->k_list); |
1055 | spin_unlock(lock: &device_klist->k_lock); |
1056 | subsys_put(sp); |
1057 | } |
1058 | EXPORT_SYMBOL_GPL(bus_sort_breadthfirst); |
1059 | |
1060 | struct subsys_dev_iter { |
1061 | struct klist_iter ki; |
1062 | const struct device_type *type; |
1063 | }; |
1064 | |
1065 | /** |
1066 | * subsys_dev_iter_init - initialize subsys device iterator |
1067 | * @iter: subsys iterator to initialize |
1068 | * @sp: the subsys private (i.e. bus) we wanna iterate over |
1069 | * @start: the device to start iterating from, if any |
1070 | * @type: device_type of the devices to iterate over, NULL for all |
1071 | * |
1072 | * Initialize subsys iterator @iter such that it iterates over devices |
1073 | * of @subsys. If @start is set, the list iteration will start there, |
1074 | * otherwise if it is NULL, the iteration starts at the beginning of |
1075 | * the list. |
1076 | */ |
1077 | static void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct subsys_private *sp, |
1078 | struct device *start, const struct device_type *type) |
1079 | { |
1080 | struct klist_node *start_knode = NULL; |
1081 | |
1082 | if (start) |
1083 | start_knode = &start->p->knode_bus; |
1084 | klist_iter_init_node(k: &sp->klist_devices, i: &iter->ki, n: start_knode); |
1085 | iter->type = type; |
1086 | } |
1087 | |
1088 | /** |
1089 | * subsys_dev_iter_next - iterate to the next device |
1090 | * @iter: subsys iterator to proceed |
1091 | * |
1092 | * Proceed @iter to the next device and return it. Returns NULL if |
1093 | * iteration is complete. |
1094 | * |
1095 | * The returned device is referenced and won't be released till |
1096 | * iterator is proceed to the next device or exited. The caller is |
1097 | * free to do whatever it wants to do with the device including |
1098 | * calling back into subsys code. |
1099 | */ |
1100 | static struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter) |
1101 | { |
1102 | struct klist_node *knode; |
1103 | struct device *dev; |
1104 | |
1105 | for (;;) { |
1106 | knode = klist_next(i: &iter->ki); |
1107 | if (!knode) |
1108 | return NULL; |
1109 | dev = to_device_private_bus(knode)->device; |
1110 | if (!iter->type || iter->type == dev->type) |
1111 | return dev; |
1112 | } |
1113 | } |
1114 | |
1115 | /** |
1116 | * subsys_dev_iter_exit - finish iteration |
1117 | * @iter: subsys iterator to finish |
1118 | * |
1119 | * Finish an iteration. Always call this function after iteration is |
1120 | * complete whether the iteration ran till the end or not. |
1121 | */ |
1122 | static void subsys_dev_iter_exit(struct subsys_dev_iter *iter) |
1123 | { |
1124 | klist_iter_exit(i: &iter->ki); |
1125 | } |
1126 | |
1127 | int subsys_interface_register(struct subsys_interface *sif) |
1128 | { |
1129 | struct subsys_private *sp; |
1130 | struct subsys_dev_iter iter; |
1131 | struct device *dev; |
1132 | |
1133 | if (!sif || !sif->subsys) |
1134 | return -ENODEV; |
1135 | |
1136 | sp = bus_to_subsys(bus: sif->subsys); |
1137 | if (!sp) |
1138 | return -EINVAL; |
1139 | |
1140 | /* |
1141 | * Reference in sp is now incremented and will be dropped when |
1142 | * the interface is removed from the bus |
1143 | */ |
1144 | |
1145 | mutex_lock(&sp->mutex); |
1146 | list_add_tail(new: &sif->node, head: &sp->interfaces); |
1147 | if (sif->add_dev) { |
1148 | subsys_dev_iter_init(iter: &iter, sp, NULL, NULL); |
1149 | while ((dev = subsys_dev_iter_next(iter: &iter))) |
1150 | sif->add_dev(dev, sif); |
1151 | subsys_dev_iter_exit(iter: &iter); |
1152 | } |
1153 | mutex_unlock(lock: &sp->mutex); |
1154 | |
1155 | return 0; |
1156 | } |
1157 | EXPORT_SYMBOL_GPL(subsys_interface_register); |
1158 | |
1159 | void subsys_interface_unregister(struct subsys_interface *sif) |
1160 | { |
1161 | struct subsys_private *sp; |
1162 | struct subsys_dev_iter iter; |
1163 | struct device *dev; |
1164 | |
1165 | if (!sif || !sif->subsys) |
1166 | return; |
1167 | |
1168 | sp = bus_to_subsys(bus: sif->subsys); |
1169 | if (!sp) |
1170 | return; |
1171 | |
1172 | mutex_lock(&sp->mutex); |
1173 | list_del_init(entry: &sif->node); |
1174 | if (sif->remove_dev) { |
1175 | subsys_dev_iter_init(iter: &iter, sp, NULL, NULL); |
1176 | while ((dev = subsys_dev_iter_next(iter: &iter))) |
1177 | sif->remove_dev(dev, sif); |
1178 | subsys_dev_iter_exit(iter: &iter); |
1179 | } |
1180 | mutex_unlock(lock: &sp->mutex); |
1181 | |
1182 | /* |
1183 | * Decrement the reference count twice, once for the bus_to_subsys() |
1184 | * call in the start of this function, and the second one from the |
1185 | * reference increment in subsys_interface_register() |
1186 | */ |
1187 | subsys_put(sp); |
1188 | subsys_put(sp); |
1189 | } |
1190 | EXPORT_SYMBOL_GPL(subsys_interface_unregister); |
1191 | |
1192 | static void system_root_device_release(struct device *dev) |
1193 | { |
1194 | kfree(objp: dev); |
1195 | } |
1196 | |
1197 | static int subsys_register(struct bus_type *subsys, |
1198 | const struct attribute_group **groups, |
1199 | struct kobject *parent_of_root) |
1200 | { |
1201 | struct subsys_private *sp; |
1202 | struct device *dev; |
1203 | int err; |
1204 | |
1205 | err = bus_register(subsys); |
1206 | if (err < 0) |
1207 | return err; |
1208 | |
1209 | sp = bus_to_subsys(bus: subsys); |
1210 | if (!sp) { |
1211 | err = -EINVAL; |
1212 | goto err_sp; |
1213 | } |
1214 | |
1215 | dev = kzalloc(size: sizeof(struct device), GFP_KERNEL); |
1216 | if (!dev) { |
1217 | err = -ENOMEM; |
1218 | goto err_dev; |
1219 | } |
1220 | |
1221 | err = dev_set_name(dev, name: "%s" , subsys->name); |
1222 | if (err < 0) |
1223 | goto err_name; |
1224 | |
1225 | dev->kobj.parent = parent_of_root; |
1226 | dev->groups = groups; |
1227 | dev->release = system_root_device_release; |
1228 | |
1229 | err = device_register(dev); |
1230 | if (err < 0) |
1231 | goto err_dev_reg; |
1232 | |
1233 | sp->dev_root = dev; |
1234 | subsys_put(sp); |
1235 | return 0; |
1236 | |
1237 | err_dev_reg: |
1238 | put_device(dev); |
1239 | dev = NULL; |
1240 | err_name: |
1241 | kfree(objp: dev); |
1242 | err_dev: |
1243 | subsys_put(sp); |
1244 | err_sp: |
1245 | bus_unregister(subsys); |
1246 | return err; |
1247 | } |
1248 | |
1249 | /** |
1250 | * subsys_system_register - register a subsystem at /sys/devices/system/ |
1251 | * @subsys: system subsystem |
1252 | * @groups: default attributes for the root device |
1253 | * |
1254 | * All 'system' subsystems have a /sys/devices/system/<name> root device |
1255 | * with the name of the subsystem. The root device can carry subsystem- |
1256 | * wide attributes. All registered devices are below this single root |
1257 | * device and are named after the subsystem with a simple enumeration |
1258 | * number appended. The registered devices are not explicitly named; |
1259 | * only 'id' in the device needs to be set. |
1260 | * |
1261 | * Do not use this interface for anything new, it exists for compatibility |
1262 | * with bad ideas only. New subsystems should use plain subsystems; and |
1263 | * add the subsystem-wide attributes should be added to the subsystem |
1264 | * directory itself and not some create fake root-device placed in |
1265 | * /sys/devices/system/<name>. |
1266 | */ |
1267 | int subsys_system_register(struct bus_type *subsys, |
1268 | const struct attribute_group **groups) |
1269 | { |
1270 | return subsys_register(subsys, groups, parent_of_root: &system_kset->kobj); |
1271 | } |
1272 | EXPORT_SYMBOL_GPL(subsys_system_register); |
1273 | |
1274 | /** |
1275 | * subsys_virtual_register - register a subsystem at /sys/devices/virtual/ |
1276 | * @subsys: virtual subsystem |
1277 | * @groups: default attributes for the root device |
1278 | * |
1279 | * All 'virtual' subsystems have a /sys/devices/system/<name> root device |
1280 | * with the name of the subystem. The root device can carry subsystem-wide |
1281 | * attributes. All registered devices are below this single root device. |
1282 | * There's no restriction on device naming. This is for kernel software |
1283 | * constructs which need sysfs interface. |
1284 | */ |
1285 | int subsys_virtual_register(struct bus_type *subsys, |
1286 | const struct attribute_group **groups) |
1287 | { |
1288 | struct kobject *virtual_dir; |
1289 | |
1290 | virtual_dir = virtual_device_parent(NULL); |
1291 | if (!virtual_dir) |
1292 | return -ENOMEM; |
1293 | |
1294 | return subsys_register(subsys, groups, parent_of_root: virtual_dir); |
1295 | } |
1296 | EXPORT_SYMBOL_GPL(subsys_virtual_register); |
1297 | |
1298 | /** |
1299 | * driver_find - locate driver on a bus by its name. |
1300 | * @name: name of the driver. |
1301 | * @bus: bus to scan for the driver. |
1302 | * |
1303 | * Call kset_find_obj() to iterate over list of drivers on |
1304 | * a bus to find driver by name. Return driver if found. |
1305 | * |
1306 | * This routine provides no locking to prevent the driver it returns |
1307 | * from being unregistered or unloaded while the caller is using it. |
1308 | * The caller is responsible for preventing this. |
1309 | */ |
1310 | struct device_driver *driver_find(const char *name, const struct bus_type *bus) |
1311 | { |
1312 | struct subsys_private *sp = bus_to_subsys(bus); |
1313 | struct kobject *k; |
1314 | struct driver_private *priv; |
1315 | |
1316 | if (!sp) |
1317 | return NULL; |
1318 | |
1319 | k = kset_find_obj(sp->drivers_kset, name); |
1320 | subsys_put(sp); |
1321 | if (!k) |
1322 | return NULL; |
1323 | |
1324 | priv = to_driver(k); |
1325 | |
1326 | /* Drop reference added by kset_find_obj() */ |
1327 | kobject_put(kobj: k); |
1328 | return priv->driver; |
1329 | } |
1330 | EXPORT_SYMBOL_GPL(driver_find); |
1331 | |
1332 | /* |
1333 | * Warning, the value could go to "removed" instantly after calling this function, so be very |
1334 | * careful when calling it... |
1335 | */ |
1336 | bool bus_is_registered(const struct bus_type *bus) |
1337 | { |
1338 | struct subsys_private *sp = bus_to_subsys(bus); |
1339 | bool is_initialized = false; |
1340 | |
1341 | if (sp) { |
1342 | is_initialized = true; |
1343 | subsys_put(sp); |
1344 | } |
1345 | return is_initialized; |
1346 | } |
1347 | |
1348 | /** |
1349 | * bus_get_dev_root - return a pointer to the "device root" of a bus |
1350 | * @bus: bus to return the device root of. |
1351 | * |
1352 | * If a bus has a "device root" structure, return it, WITH THE REFERENCE |
1353 | * COUNT INCREMENTED. |
1354 | * |
1355 | * Note, when finished with the device, a call to put_device() is required. |
1356 | * |
1357 | * If the device root is not present (or bus is not a valid pointer), NULL |
1358 | * will be returned. |
1359 | */ |
1360 | struct device *bus_get_dev_root(const struct bus_type *bus) |
1361 | { |
1362 | struct subsys_private *sp = bus_to_subsys(bus); |
1363 | struct device *dev_root; |
1364 | |
1365 | if (!sp) |
1366 | return NULL; |
1367 | |
1368 | dev_root = get_device(dev: sp->dev_root); |
1369 | subsys_put(sp); |
1370 | return dev_root; |
1371 | } |
1372 | EXPORT_SYMBOL_GPL(bus_get_dev_root); |
1373 | |
1374 | int __init buses_init(void) |
1375 | { |
1376 | bus_kset = kset_create_and_add(name: "bus" , u: &bus_uevent_ops, NULL); |
1377 | if (!bus_kset) |
1378 | return -ENOMEM; |
1379 | |
1380 | system_kset = kset_create_and_add(name: "system" , NULL, parent_kobj: &devices_kset->kobj); |
1381 | if (!system_kset) |
1382 | return -ENOMEM; |
1383 | |
1384 | return 0; |
1385 | } |
1386 | |