Line data Source code
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/bus.h>
13 : #include <linux/device.h>
14 : #include <linux/module.h>
15 : #include <linux/errno.h>
16 : #include <linux/slab.h>
17 : #include <linux/init.h>
18 : #include <linux/string.h>
19 : #include <linux/mutex.h>
20 : #include <linux/sysfs.h>
21 : #include "base.h"
22 : #include "power/power.h"
23 :
24 : /* /sys/devices/system */
25 : static struct kset *system_kset;
26 :
27 : #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
28 :
29 : /*
30 : * sysfs bindings for drivers
31 : */
32 :
33 : #define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
34 :
35 : #define DRIVER_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \
36 : struct driver_attribute driver_attr_##_name = \
37 : __ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store)
38 :
39 : static int __must_check bus_rescan_devices_helper(struct device *dev,
40 : void *data);
41 :
42 : static struct bus_type *bus_get(struct bus_type *bus)
43 : {
44 587 : if (bus) {
45 55 : kset_get(&bus->p->subsys);
46 : return bus;
47 : }
48 : return NULL;
49 : }
50 :
51 : static void bus_put(struct bus_type *bus)
52 : {
53 35 : if (bus)
54 35 : kset_put(&bus->p->subsys);
55 : }
56 :
57 0 : static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr,
58 : char *buf)
59 : {
60 0 : struct driver_attribute *drv_attr = to_drv_attr(attr);
61 0 : struct driver_private *drv_priv = to_driver(kobj);
62 0 : ssize_t ret = -EIO;
63 :
64 0 : if (drv_attr->show)
65 0 : ret = drv_attr->show(drv_priv->driver, buf);
66 0 : return ret;
67 : }
68 :
69 0 : static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr,
70 : const char *buf, size_t count)
71 : {
72 0 : struct driver_attribute *drv_attr = to_drv_attr(attr);
73 0 : struct driver_private *drv_priv = to_driver(kobj);
74 0 : ssize_t ret = -EIO;
75 :
76 0 : if (drv_attr->store)
77 0 : ret = drv_attr->store(drv_priv->driver, buf, count);
78 0 : return ret;
79 : }
80 :
81 : static const struct sysfs_ops driver_sysfs_ops = {
82 : .show = drv_attr_show,
83 : .store = drv_attr_store,
84 : };
85 :
86 1 : static void driver_release(struct kobject *kobj)
87 : {
88 1 : struct driver_private *drv_priv = to_driver(kobj);
89 :
90 : pr_debug("driver: '%s': %s\n", kobject_name(kobj), __func__);
91 1 : kfree(drv_priv);
92 1 : }
93 :
94 : static struct kobj_type driver_ktype = {
95 : .sysfs_ops = &driver_sysfs_ops,
96 : .release = driver_release,
97 : };
98 :
99 : /*
100 : * sysfs bindings for buses
101 : */
102 0 : static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr,
103 : char *buf)
104 : {
105 0 : struct bus_attribute *bus_attr = to_bus_attr(attr);
106 0 : struct subsys_private *subsys_priv = to_subsys_private(kobj);
107 0 : ssize_t ret = 0;
108 :
109 0 : if (bus_attr->show)
110 0 : ret = bus_attr->show(subsys_priv->bus, buf);
111 0 : return ret;
112 : }
113 :
114 0 : static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr,
115 : const char *buf, size_t count)
116 : {
117 0 : struct bus_attribute *bus_attr = to_bus_attr(attr);
118 0 : struct subsys_private *subsys_priv = to_subsys_private(kobj);
119 0 : ssize_t ret = 0;
120 :
121 0 : if (bus_attr->store)
122 0 : ret = bus_attr->store(subsys_priv->bus, buf, count);
123 0 : return ret;
124 : }
125 :
126 : static const struct sysfs_ops bus_sysfs_ops = {
127 : .show = bus_attr_show,
128 : .store = bus_attr_store,
129 : };
130 :
131 34 : int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)
132 : {
133 : int error;
134 34 : if (bus_get(bus)) {
135 68 : error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);
136 : bus_put(bus);
137 : } else
138 : error = -EINVAL;
139 34 : return error;
140 : }
141 : EXPORT_SYMBOL_GPL(bus_create_file);
142 :
143 0 : void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr)
144 : {
145 0 : if (bus_get(bus)) {
146 0 : sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr);
147 : bus_put(bus);
148 : }
149 0 : }
150 : EXPORT_SYMBOL_GPL(bus_remove_file);
151 :
152 0 : static void bus_release(struct kobject *kobj)
153 : {
154 0 : struct subsys_private *priv = to_subsys_private(kobj);
155 0 : struct bus_type *bus = priv->bus;
156 :
157 0 : kfree(priv);
158 0 : bus->p = NULL;
159 0 : }
160 :
161 : static struct kobj_type bus_ktype = {
162 : .sysfs_ops = &bus_sysfs_ops,
163 : .release = bus_release,
164 : };
165 :
166 34 : static int bus_uevent_filter(struct kobject *kobj)
167 : {
168 34 : const struct kobj_type *ktype = get_ktype(kobj);
169 :
170 34 : if (ktype == &bus_ktype)
171 : return 1;
172 23 : return 0;
173 : }
174 :
175 : static const struct kset_uevent_ops bus_uevent_ops = {
176 : .filter = bus_uevent_filter,
177 : };
178 :
179 : static struct kset *bus_kset;
180 :
181 : /* Manually detach a device from its associated driver. */
182 0 : static ssize_t unbind_store(struct device_driver *drv, const char *buf,
183 : size_t count)
184 : {
185 0 : struct bus_type *bus = bus_get(drv->bus);
186 : struct device *dev;
187 0 : int err = -ENODEV;
188 :
189 0 : dev = bus_find_device_by_name(bus, NULL, buf);
190 0 : if (dev && dev->driver == drv) {
191 0 : device_driver_detach(dev);
192 0 : err = count;
193 : }
194 0 : put_device(dev);
195 0 : bus_put(bus);
196 0 : return err;
197 : }
198 : static DRIVER_ATTR_IGNORE_LOCKDEP(unbind, 0200, NULL, unbind_store);
199 :
200 : /*
201 : * Manually attach a device to a driver.
202 : * Note: the driver must want to bind to the device,
203 : * it is not possible to override the driver's id table.
204 : */
205 0 : static ssize_t bind_store(struct device_driver *drv, const char *buf,
206 : size_t count)
207 : {
208 0 : struct bus_type *bus = bus_get(drv->bus);
209 : struct device *dev;
210 0 : int err = -ENODEV;
211 :
212 0 : dev = bus_find_device_by_name(bus, NULL, buf);
213 0 : if (dev && driver_match_device(drv, dev)) {
214 0 : err = device_driver_attach(drv, dev);
215 0 : if (!err) {
216 : /* success */
217 0 : err = count;
218 : }
219 : }
220 0 : put_device(dev);
221 0 : bus_put(bus);
222 0 : return err;
223 : }
224 : static DRIVER_ATTR_IGNORE_LOCKDEP(bind, 0200, NULL, bind_store);
225 :
226 0 : static ssize_t drivers_autoprobe_show(struct bus_type *bus, char *buf)
227 : {
228 0 : return sysfs_emit(buf, "%d\n", bus->p->drivers_autoprobe);
229 : }
230 :
231 0 : static ssize_t drivers_autoprobe_store(struct bus_type *bus,
232 : const char *buf, size_t count)
233 : {
234 0 : if (buf[0] == '0')
235 0 : bus->p->drivers_autoprobe = 0;
236 : else
237 0 : bus->p->drivers_autoprobe = 1;
238 0 : return count;
239 : }
240 :
241 0 : static ssize_t drivers_probe_store(struct bus_type *bus,
242 : const char *buf, size_t count)
243 : {
244 : struct device *dev;
245 0 : int err = -EINVAL;
246 :
247 0 : dev = bus_find_device_by_name(bus, NULL, buf);
248 0 : if (!dev)
249 : return -ENODEV;
250 0 : if (bus_rescan_devices_helper(dev, NULL) == 0)
251 0 : err = count;
252 0 : put_device(dev);
253 0 : return err;
254 : }
255 :
256 : static struct device *next_device(struct klist_iter *i)
257 : {
258 35 : struct klist_node *n = klist_next(i);
259 35 : struct device *dev = NULL;
260 : struct device_private *dev_prv;
261 :
262 35 : if (n) {
263 0 : dev_prv = to_device_private_bus(n);
264 0 : dev = dev_prv->device;
265 : }
266 : return dev;
267 : }
268 :
269 : /**
270 : * bus_for_each_dev - device iterator.
271 : * @bus: bus type.
272 : * @start: device to start iterating from.
273 : * @data: data for the callback.
274 : * @fn: function to be called for each device.
275 : *
276 : * Iterate over @bus's list of devices, and call @fn for each,
277 : * passing it @data. If @start is not NULL, we use that device to
278 : * begin iterating from.
279 : *
280 : * We check the return of @fn each time. If it returns anything
281 : * other than 0, we break out and return that value.
282 : *
283 : * NOTE: The device that returns a non-zero value is not retained
284 : * in any way, nor is its refcount incremented. If the caller needs
285 : * to retain this data, it should do so, and increment the reference
286 : * count in the supplied callback.
287 : */
288 31 : int bus_for_each_dev(struct bus_type *bus, struct device *start,
289 : void *data, int (*fn)(struct device *, void *))
290 : {
291 : struct klist_iter i;
292 : struct device *dev;
293 31 : int error = 0;
294 :
295 31 : if (!bus || !bus->p)
296 : return -EINVAL;
297 :
298 31 : klist_iter_init_node(&bus->p->klist_devices, &i,
299 0 : (start ? &start->p->knode_bus : NULL));
300 93 : while (!error && (dev = next_device(&i)))
301 0 : error = fn(dev, data);
302 31 : klist_iter_exit(&i);
303 31 : return error;
304 : }
305 : EXPORT_SYMBOL_GPL(bus_for_each_dev);
306 :
307 : /**
308 : * bus_find_device - device iterator for locating a particular device.
309 : * @bus: bus type
310 : * @start: Device to begin with
311 : * @data: Data to pass to match function
312 : * @match: Callback function to check device
313 : *
314 : * This is similar to the bus_for_each_dev() function above, but it
315 : * returns a reference to a device that is 'found' for later use, as
316 : * determined by the @match callback.
317 : *
318 : * The callback should return 0 if the device doesn't match and non-zero
319 : * if it does. If the callback returns non-zero, this function will
320 : * return to the caller and not iterate over any more devices.
321 : */
322 4 : struct device *bus_find_device(struct bus_type *bus,
323 : struct device *start, const void *data,
324 : int (*match)(struct device *dev, const void *data))
325 : {
326 : struct klist_iter i;
327 : struct device *dev;
328 :
329 4 : if (!bus || !bus->p)
330 : return NULL;
331 :
332 4 : klist_iter_init_node(&bus->p->klist_devices, &i,
333 0 : (start ? &start->p->knode_bus : NULL));
334 8 : while ((dev = next_device(&i)))
335 0 : if (match(dev, data) && get_device(dev))
336 : break;
337 4 : klist_iter_exit(&i);
338 4 : return dev;
339 : }
340 : EXPORT_SYMBOL_GPL(bus_find_device);
341 :
342 : /**
343 : * subsys_find_device_by_id - find a device with a specific enumeration number
344 : * @subsys: subsystem
345 : * @id: index 'id' in struct device
346 : * @hint: device to check first
347 : *
348 : * Check the hint's next object and if it is a match return it directly,
349 : * otherwise, fall back to a full list search. Either way a reference for
350 : * the returned object is taken.
351 : */
352 0 : struct device *subsys_find_device_by_id(struct bus_type *subsys, unsigned int id,
353 : struct device *hint)
354 : {
355 : struct klist_iter i;
356 : struct device *dev;
357 :
358 0 : if (!subsys)
359 : return NULL;
360 :
361 0 : if (hint) {
362 0 : klist_iter_init_node(&subsys->p->klist_devices, &i, &hint->p->knode_bus);
363 0 : dev = next_device(&i);
364 0 : if (dev && dev->id == id && get_device(dev)) {
365 0 : klist_iter_exit(&i);
366 0 : return dev;
367 : }
368 0 : klist_iter_exit(&i);
369 : }
370 :
371 0 : klist_iter_init_node(&subsys->p->klist_devices, &i, NULL);
372 0 : while ((dev = next_device(&i))) {
373 0 : if (dev->id == id && get_device(dev)) {
374 0 : klist_iter_exit(&i);
375 0 : return dev;
376 : }
377 : }
378 0 : klist_iter_exit(&i);
379 0 : return NULL;
380 : }
381 : EXPORT_SYMBOL_GPL(subsys_find_device_by_id);
382 :
383 : static struct device_driver *next_driver(struct klist_iter *i)
384 : {
385 81 : struct klist_node *n = klist_next(i);
386 : struct driver_private *drv_priv;
387 :
388 81 : if (n) {
389 66 : drv_priv = container_of(n, struct driver_private, knode_bus);
390 66 : return drv_priv->driver;
391 : }
392 : return NULL;
393 : }
394 :
395 : /**
396 : * bus_for_each_drv - driver iterator
397 : * @bus: bus we're dealing with.
398 : * @start: driver to start iterating on.
399 : * @data: data to pass to the callback.
400 : * @fn: function to call for each driver.
401 : *
402 : * This is nearly identical to the device iterator above.
403 : * We iterate over each driver that belongs to @bus, and call
404 : * @fn for each. If @fn returns anything but 0, we break out
405 : * and return it. If @start is not NULL, we use it as the head
406 : * of the list.
407 : *
408 : * NOTE: we don't return the driver that returns a non-zero
409 : * value, nor do we leave the reference count incremented for that
410 : * driver. If the caller needs to know that info, it must set it
411 : * in the callback. It must also be sure to increment the refcount
412 : * so it doesn't disappear before returning to the caller.
413 : */
414 15 : int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
415 : void *data, int (*fn)(struct device_driver *, void *))
416 : {
417 : struct klist_iter i;
418 : struct device_driver *drv;
419 15 : int error = 0;
420 :
421 15 : if (!bus)
422 : return -EINVAL;
423 :
424 15 : klist_iter_init_node(&bus->p->klist_drivers, &i,
425 0 : start ? &start->p->knode_bus : NULL);
426 96 : while ((drv = next_driver(&i)) && !error)
427 66 : error = fn(drv, data);
428 15 : klist_iter_exit(&i);
429 15 : return error;
430 : }
431 : EXPORT_SYMBOL_GPL(bus_for_each_drv);
432 :
433 : /**
434 : * bus_add_device - add device to bus
435 : * @dev: device being added
436 : *
437 : * - Add device's bus attributes.
438 : * - Create links to device's bus.
439 : * - Add the device to its bus's list of devices.
440 : */
441 536 : int bus_add_device(struct device *dev)
442 : {
443 1072 : struct bus_type *bus = bus_get(dev->bus);
444 536 : int error = 0;
445 :
446 536 : if (bus) {
447 : pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev));
448 4 : error = device_add_groups(dev, bus->dev_groups);
449 4 : if (error)
450 : goto out_put;
451 4 : error = sysfs_create_link(&bus->p->devices_kset->kobj,
452 : &dev->kobj, dev_name(dev));
453 4 : if (error)
454 : goto out_groups;
455 4 : error = sysfs_create_link(&dev->kobj,
456 4 : &dev->bus->p->subsys.kobj, "subsystem");
457 4 : if (error)
458 : goto out_subsys;
459 4 : klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);
460 : }
461 : return 0;
462 :
463 : out_subsys:
464 0 : sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev));
465 : out_groups:
466 0 : device_remove_groups(dev, bus->dev_groups);
467 : out_put:
468 0 : bus_put(dev->bus);
469 : return error;
470 : }
471 :
472 : /**
473 : * bus_probe_device - probe drivers for a new device
474 : * @dev: device to probe
475 : *
476 : * - Automatically probe for a driver if the bus allows it.
477 : */
478 536 : void bus_probe_device(struct device *dev)
479 : {
480 536 : struct bus_type *bus = dev->bus;
481 : struct subsys_interface *sif;
482 :
483 536 : if (!bus)
484 : return;
485 :
486 4 : if (bus->p->drivers_autoprobe)
487 4 : device_initial_probe(dev);
488 :
489 4 : mutex_lock(&bus->p->mutex);
490 4 : list_for_each_entry(sif, &bus->p->interfaces, node)
491 0 : if (sif->add_dev)
492 0 : sif->add_dev(dev, sif);
493 4 : mutex_unlock(&bus->p->mutex);
494 : }
495 :
496 : /**
497 : * bus_remove_device - remove device from bus
498 : * @dev: device to be removed
499 : *
500 : * - Remove device from all interfaces.
501 : * - Remove symlink from bus' directory.
502 : * - Delete device from bus's list.
503 : * - Detach from its driver.
504 : * - Drop reference taken in bus_add_device().
505 : */
506 0 : void bus_remove_device(struct device *dev)
507 : {
508 0 : struct bus_type *bus = dev->bus;
509 : struct subsys_interface *sif;
510 :
511 0 : if (!bus)
512 : return;
513 :
514 0 : mutex_lock(&bus->p->mutex);
515 0 : list_for_each_entry(sif, &bus->p->interfaces, node)
516 0 : if (sif->remove_dev)
517 0 : sif->remove_dev(dev, sif);
518 0 : mutex_unlock(&bus->p->mutex);
519 :
520 0 : sysfs_remove_link(&dev->kobj, "subsystem");
521 0 : sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
522 : dev_name(dev));
523 0 : device_remove_groups(dev, dev->bus->dev_groups);
524 0 : if (klist_node_attached(&dev->p->knode_bus))
525 0 : klist_del(&dev->p->knode_bus);
526 :
527 : pr_debug("bus: '%s': remove device %s\n",
528 : dev->bus->name, dev_name(dev));
529 0 : device_release_driver(dev);
530 0 : bus_put(dev->bus);
531 : }
532 :
533 17 : static int __must_check add_bind_files(struct device_driver *drv)
534 : {
535 : int ret;
536 :
537 17 : ret = driver_create_file(drv, &driver_attr_unbind);
538 17 : if (ret == 0) {
539 17 : ret = driver_create_file(drv, &driver_attr_bind);
540 17 : if (ret)
541 0 : driver_remove_file(drv, &driver_attr_unbind);
542 : }
543 17 : return ret;
544 : }
545 :
546 : static void remove_bind_files(struct device_driver *drv)
547 : {
548 1 : driver_remove_file(drv, &driver_attr_bind);
549 1 : driver_remove_file(drv, &driver_attr_unbind);
550 : }
551 :
552 : static BUS_ATTR_WO(drivers_probe);
553 : static BUS_ATTR_RW(drivers_autoprobe);
554 :
555 11 : static int add_probe_files(struct bus_type *bus)
556 : {
557 : int retval;
558 :
559 11 : retval = bus_create_file(bus, &bus_attr_drivers_probe);
560 11 : if (retval)
561 : goto out;
562 :
563 11 : retval = bus_create_file(bus, &bus_attr_drivers_autoprobe);
564 11 : if (retval)
565 0 : bus_remove_file(bus, &bus_attr_drivers_probe);
566 : out:
567 11 : return retval;
568 : }
569 :
570 : static void remove_probe_files(struct bus_type *bus)
571 : {
572 0 : bus_remove_file(bus, &bus_attr_drivers_autoprobe);
573 0 : bus_remove_file(bus, &bus_attr_drivers_probe);
574 : }
575 :
576 0 : static ssize_t uevent_store(struct device_driver *drv, const char *buf,
577 : size_t count)
578 : {
579 : int rc;
580 :
581 0 : rc = kobject_synth_uevent(&drv->p->kobj, buf, count);
582 0 : return rc ? rc : count;
583 : }
584 : static DRIVER_ATTR_WO(uevent);
585 :
586 : /**
587 : * bus_add_driver - Add a driver to the bus.
588 : * @drv: driver.
589 : */
590 17 : int bus_add_driver(struct device_driver *drv)
591 : {
592 : struct bus_type *bus;
593 : struct driver_private *priv;
594 17 : int error = 0;
595 :
596 34 : bus = bus_get(drv->bus);
597 17 : if (!bus)
598 : return -EINVAL;
599 :
600 : pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name);
601 :
602 17 : priv = kzalloc(sizeof(*priv), GFP_KERNEL);
603 17 : if (!priv) {
604 : error = -ENOMEM;
605 : goto out_put_bus;
606 : }
607 17 : klist_init(&priv->klist_devices, NULL, NULL);
608 17 : priv->driver = drv;
609 17 : drv->p = priv;
610 17 : priv->kobj.kset = bus->p->drivers_kset;
611 17 : error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL,
612 : "%s", drv->name);
613 17 : if (error)
614 : goto out_unregister;
615 :
616 17 : klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);
617 17 : if (drv->bus->p->drivers_autoprobe) {
618 17 : error = driver_attach(drv);
619 17 : if (error)
620 : goto out_unregister;
621 : }
622 17 : module_add_driver(drv->owner, drv);
623 :
624 17 : error = driver_create_file(drv, &driver_attr_uevent);
625 17 : if (error) {
626 0 : printk(KERN_ERR "%s: uevent attr (%s) failed\n",
627 : __func__, drv->name);
628 : }
629 17 : error = driver_add_groups(drv, bus->drv_groups);
630 17 : if (error) {
631 : /* How the hell do we get out of this pickle? Give up */
632 0 : printk(KERN_ERR "%s: driver_add_groups(%s) failed\n",
633 : __func__, drv->name);
634 : }
635 :
636 17 : if (!drv->suppress_bind_attrs) {
637 17 : error = add_bind_files(drv);
638 17 : if (error) {
639 : /* Ditto */
640 0 : printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
641 : __func__, drv->name);
642 : }
643 : }
644 :
645 : return 0;
646 :
647 : out_unregister:
648 0 : kobject_put(&priv->kobj);
649 : /* drv->p is freed in driver_release() */
650 0 : drv->p = NULL;
651 : out_put_bus:
652 0 : bus_put(bus);
653 0 : return error;
654 : }
655 :
656 : /**
657 : * bus_remove_driver - delete driver from bus's knowledge.
658 : * @drv: driver.
659 : *
660 : * Detach the driver from the devices it controls, and remove
661 : * it from its bus's list of drivers. Finally, we drop the reference
662 : * to the bus we took in bus_add_driver().
663 : */
664 1 : void bus_remove_driver(struct device_driver *drv)
665 : {
666 1 : if (!drv->bus)
667 : return;
668 :
669 1 : if (!drv->suppress_bind_attrs)
670 : remove_bind_files(drv);
671 1 : driver_remove_groups(drv, drv->bus->drv_groups);
672 1 : driver_remove_file(drv, &driver_attr_uevent);
673 1 : klist_remove(&drv->p->knode_bus);
674 : pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name);
675 1 : driver_detach(drv);
676 1 : module_remove_driver(drv);
677 1 : kobject_put(&drv->p->kobj);
678 1 : bus_put(drv->bus);
679 : }
680 :
681 : /* Helper for bus_rescan_devices's iter */
682 0 : static int __must_check bus_rescan_devices_helper(struct device *dev,
683 : void *data)
684 : {
685 0 : int ret = 0;
686 :
687 0 : if (!dev->driver) {
688 0 : if (dev->parent && dev->bus->need_parent_lock)
689 0 : device_lock(dev->parent);
690 0 : ret = device_attach(dev);
691 0 : if (dev->parent && dev->bus->need_parent_lock)
692 0 : device_unlock(dev->parent);
693 : }
694 0 : return ret < 0 ? ret : 0;
695 : }
696 :
697 : /**
698 : * bus_rescan_devices - rescan devices on the bus for possible drivers
699 : * @bus: the bus to scan.
700 : *
701 : * This function will look for devices on the bus with no driver
702 : * attached and rescan it against existing drivers to see if it matches
703 : * any by calling device_attach() for the unbound devices.
704 : */
705 0 : int bus_rescan_devices(struct bus_type *bus)
706 : {
707 0 : return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
708 : }
709 : EXPORT_SYMBOL_GPL(bus_rescan_devices);
710 :
711 : /**
712 : * device_reprobe - remove driver for a device and probe for a new driver
713 : * @dev: the device to reprobe
714 : *
715 : * This function detaches the attached driver (if any) for the given
716 : * device and restarts the driver probing process. It is intended
717 : * to use if probing criteria changed during a devices lifetime and
718 : * driver attachment should change accordingly.
719 : */
720 0 : int device_reprobe(struct device *dev)
721 : {
722 0 : if (dev->driver)
723 0 : device_driver_detach(dev);
724 0 : return bus_rescan_devices_helper(dev, NULL);
725 : }
726 : EXPORT_SYMBOL_GPL(device_reprobe);
727 :
728 : static int bus_add_groups(struct bus_type *bus,
729 : const struct attribute_group **groups)
730 : {
731 11 : return sysfs_create_groups(&bus->p->subsys.kobj, groups);
732 : }
733 :
734 : static void bus_remove_groups(struct bus_type *bus,
735 : const struct attribute_group **groups)
736 : {
737 0 : sysfs_remove_groups(&bus->p->subsys.kobj, groups);
738 : }
739 :
740 4 : static void klist_devices_get(struct klist_node *n)
741 : {
742 4 : struct device_private *dev_prv = to_device_private_bus(n);
743 4 : struct device *dev = dev_prv->device;
744 :
745 4 : get_device(dev);
746 4 : }
747 :
748 0 : static void klist_devices_put(struct klist_node *n)
749 : {
750 0 : struct device_private *dev_prv = to_device_private_bus(n);
751 0 : struct device *dev = dev_prv->device;
752 :
753 0 : put_device(dev);
754 0 : }
755 :
756 0 : static ssize_t bus_uevent_store(struct bus_type *bus,
757 : const char *buf, size_t count)
758 : {
759 : int rc;
760 :
761 0 : rc = kobject_synth_uevent(&bus->p->subsys.kobj, buf, count);
762 0 : return rc ? rc : count;
763 : }
764 : /*
765 : * "open code" the old BUS_ATTR() macro here. We want to use BUS_ATTR_WO()
766 : * here, but can not use it as earlier in the file we have
767 : * DEVICE_ATTR_WO(uevent), which would cause a clash with the with the store
768 : * function name.
769 : */
770 : static struct bus_attribute bus_attr_uevent = __ATTR(uevent, 0200, NULL,
771 : bus_uevent_store);
772 :
773 : /**
774 : * bus_register - register a driver-core subsystem
775 : * @bus: bus to register
776 : *
777 : * Once we have that, we register the bus with the kobject
778 : * infrastructure, then register the children subsystems it has:
779 : * the devices and drivers that belong to the subsystem.
780 : */
781 11 : int bus_register(struct bus_type *bus)
782 : {
783 : int retval;
784 : struct subsys_private *priv;
785 11 : struct lock_class_key *key = &bus->lock_key;
786 :
787 11 : priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL);
788 11 : if (!priv)
789 : return -ENOMEM;
790 :
791 11 : priv->bus = bus;
792 11 : bus->p = priv;
793 :
794 11 : BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier);
795 :
796 11 : retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);
797 11 : if (retval)
798 : goto out;
799 :
800 11 : priv->subsys.kobj.kset = bus_kset;
801 11 : priv->subsys.kobj.ktype = &bus_ktype;
802 11 : priv->drivers_autoprobe = 1;
803 :
804 11 : retval = kset_register(&priv->subsys);
805 11 : if (retval)
806 : goto out;
807 :
808 11 : retval = bus_create_file(bus, &bus_attr_uevent);
809 11 : if (retval)
810 : goto bus_uevent_fail;
811 :
812 11 : priv->devices_kset = kset_create_and_add("devices", NULL,
813 : &priv->subsys.kobj);
814 11 : if (!priv->devices_kset) {
815 : retval = -ENOMEM;
816 : goto bus_devices_fail;
817 : }
818 :
819 11 : priv->drivers_kset = kset_create_and_add("drivers", NULL,
820 : &priv->subsys.kobj);
821 11 : if (!priv->drivers_kset) {
822 : retval = -ENOMEM;
823 : goto bus_drivers_fail;
824 : }
825 :
826 22 : INIT_LIST_HEAD(&priv->interfaces);
827 11 : __mutex_init(&priv->mutex, "subsys mutex", key);
828 11 : klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put);
829 11 : klist_init(&priv->klist_drivers, NULL, NULL);
830 :
831 11 : retval = add_probe_files(bus);
832 11 : if (retval)
833 : goto bus_probe_files_fail;
834 :
835 22 : retval = bus_add_groups(bus, bus->bus_groups);
836 11 : if (retval)
837 : goto bus_groups_fail;
838 :
839 : pr_debug("bus: '%s': registered\n", bus->name);
840 : return 0;
841 :
842 : bus_groups_fail:
843 : remove_probe_files(bus);
844 : bus_probe_files_fail:
845 0 : kset_unregister(bus->p->drivers_kset);
846 : bus_drivers_fail:
847 0 : kset_unregister(bus->p->devices_kset);
848 : bus_devices_fail:
849 0 : bus_remove_file(bus, &bus_attr_uevent);
850 : bus_uevent_fail:
851 0 : kset_unregister(&bus->p->subsys);
852 : out:
853 0 : kfree(bus->p);
854 0 : bus->p = NULL;
855 0 : return retval;
856 : }
857 : EXPORT_SYMBOL_GPL(bus_register);
858 :
859 : /**
860 : * bus_unregister - remove a bus from the system
861 : * @bus: bus.
862 : *
863 : * Unregister the child subsystems and the bus itself.
864 : * Finally, we call bus_put() to release the refcount
865 : */
866 0 : void bus_unregister(struct bus_type *bus)
867 : {
868 : pr_debug("bus: '%s': unregistering\n", bus->name);
869 0 : if (bus->dev_root)
870 0 : device_unregister(bus->dev_root);
871 0 : bus_remove_groups(bus, bus->bus_groups);
872 0 : remove_probe_files(bus);
873 0 : kset_unregister(bus->p->drivers_kset);
874 0 : kset_unregister(bus->p->devices_kset);
875 0 : bus_remove_file(bus, &bus_attr_uevent);
876 0 : kset_unregister(&bus->p->subsys);
877 0 : }
878 : EXPORT_SYMBOL_GPL(bus_unregister);
879 :
880 2 : int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
881 : {
882 2 : return blocking_notifier_chain_register(&bus->p->bus_notifier, nb);
883 : }
884 : EXPORT_SYMBOL_GPL(bus_register_notifier);
885 :
886 0 : int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
887 : {
888 0 : return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb);
889 : }
890 : EXPORT_SYMBOL_GPL(bus_unregister_notifier);
891 :
892 1 : struct kset *bus_get_kset(struct bus_type *bus)
893 : {
894 1 : return &bus->p->subsys;
895 : }
896 : EXPORT_SYMBOL_GPL(bus_get_kset);
897 :
898 0 : struct klist *bus_get_device_klist(struct bus_type *bus)
899 : {
900 0 : return &bus->p->klist_devices;
901 : }
902 : EXPORT_SYMBOL_GPL(bus_get_device_klist);
903 :
904 : /*
905 : * Yes, this forcibly breaks the klist abstraction temporarily. It
906 : * just wants to sort the klist, not change reference counts and
907 : * take/drop locks rapidly in the process. It does all this while
908 : * holding the lock for the list, so objects can't otherwise be
909 : * added/removed while we're swizzling.
910 : */
911 0 : static void device_insertion_sort_klist(struct device *a, struct list_head *list,
912 : int (*compare)(const struct device *a,
913 : const struct device *b))
914 : {
915 : struct klist_node *n;
916 : struct device_private *dev_prv;
917 : struct device *b;
918 :
919 0 : list_for_each_entry(n, list, n_node) {
920 0 : dev_prv = to_device_private_bus(n);
921 0 : b = dev_prv->device;
922 0 : if (compare(a, b) <= 0) {
923 0 : list_move_tail(&a->p->knode_bus.n_node,
924 0 : &b->p->knode_bus.n_node);
925 : return;
926 : }
927 : }
928 0 : list_move_tail(&a->p->knode_bus.n_node, list);
929 : }
930 :
931 0 : void bus_sort_breadthfirst(struct bus_type *bus,
932 : int (*compare)(const struct device *a,
933 : const struct device *b))
934 : {
935 0 : LIST_HEAD(sorted_devices);
936 : struct klist_node *n, *tmp;
937 : struct device_private *dev_prv;
938 : struct device *dev;
939 : struct klist *device_klist;
940 :
941 0 : device_klist = bus_get_device_klist(bus);
942 :
943 0 : spin_lock(&device_klist->k_lock);
944 0 : list_for_each_entry_safe(n, tmp, &device_klist->k_list, n_node) {
945 0 : dev_prv = to_device_private_bus(n);
946 0 : dev = dev_prv->device;
947 0 : device_insertion_sort_klist(dev, &sorted_devices, compare);
948 : }
949 0 : list_splice(&sorted_devices, &device_klist->k_list);
950 0 : spin_unlock(&device_klist->k_lock);
951 0 : }
952 : EXPORT_SYMBOL_GPL(bus_sort_breadthfirst);
953 :
954 : /**
955 : * subsys_dev_iter_init - initialize subsys device iterator
956 : * @iter: subsys iterator to initialize
957 : * @subsys: the subsys we wanna iterate over
958 : * @start: the device to start iterating from, if any
959 : * @type: device_type of the devices to iterate over, NULL for all
960 : *
961 : * Initialize subsys iterator @iter such that it iterates over devices
962 : * of @subsys. If @start is set, the list iteration will start there,
963 : * otherwise if it is NULL, the iteration starts at the beginning of
964 : * the list.
965 : */
966 0 : void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct bus_type *subsys,
967 : struct device *start, const struct device_type *type)
968 : {
969 0 : struct klist_node *start_knode = NULL;
970 :
971 0 : if (start)
972 0 : start_knode = &start->p->knode_bus;
973 0 : klist_iter_init_node(&subsys->p->klist_devices, &iter->ki, start_knode);
974 0 : iter->type = type;
975 0 : }
976 : EXPORT_SYMBOL_GPL(subsys_dev_iter_init);
977 :
978 : /**
979 : * subsys_dev_iter_next - iterate to the next device
980 : * @iter: subsys iterator to proceed
981 : *
982 : * Proceed @iter to the next device and return it. Returns NULL if
983 : * iteration is complete.
984 : *
985 : * The returned device is referenced and won't be released till
986 : * iterator is proceed to the next device or exited. The caller is
987 : * free to do whatever it wants to do with the device including
988 : * calling back into subsys code.
989 : */
990 0 : struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter)
991 : {
992 : struct klist_node *knode;
993 : struct device *dev;
994 :
995 : for (;;) {
996 0 : knode = klist_next(&iter->ki);
997 0 : if (!knode)
998 : return NULL;
999 0 : dev = to_device_private_bus(knode)->device;
1000 0 : if (!iter->type || iter->type == dev->type)
1001 : return dev;
1002 : }
1003 : }
1004 : EXPORT_SYMBOL_GPL(subsys_dev_iter_next);
1005 :
1006 : /**
1007 : * subsys_dev_iter_exit - finish iteration
1008 : * @iter: subsys iterator to finish
1009 : *
1010 : * Finish an iteration. Always call this function after iteration is
1011 : * complete whether the iteration ran till the end or not.
1012 : */
1013 0 : void subsys_dev_iter_exit(struct subsys_dev_iter *iter)
1014 : {
1015 0 : klist_iter_exit(&iter->ki);
1016 0 : }
1017 : EXPORT_SYMBOL_GPL(subsys_dev_iter_exit);
1018 :
1019 0 : int subsys_interface_register(struct subsys_interface *sif)
1020 : {
1021 : struct bus_type *subsys;
1022 : struct subsys_dev_iter iter;
1023 : struct device *dev;
1024 :
1025 0 : if (!sif || !sif->subsys)
1026 : return -ENODEV;
1027 :
1028 0 : subsys = bus_get(sif->subsys);
1029 : if (!subsys)
1030 : return -EINVAL;
1031 :
1032 0 : mutex_lock(&subsys->p->mutex);
1033 0 : list_add_tail(&sif->node, &subsys->p->interfaces);
1034 0 : if (sif->add_dev) {
1035 : subsys_dev_iter_init(&iter, subsys, NULL, NULL);
1036 0 : while ((dev = subsys_dev_iter_next(&iter)))
1037 0 : sif->add_dev(dev, sif);
1038 : subsys_dev_iter_exit(&iter);
1039 : }
1040 0 : mutex_unlock(&subsys->p->mutex);
1041 :
1042 0 : return 0;
1043 : }
1044 : EXPORT_SYMBOL_GPL(subsys_interface_register);
1045 :
1046 0 : void subsys_interface_unregister(struct subsys_interface *sif)
1047 : {
1048 : struct bus_type *subsys;
1049 : struct subsys_dev_iter iter;
1050 : struct device *dev;
1051 :
1052 0 : if (!sif || !sif->subsys)
1053 0 : return;
1054 :
1055 0 : subsys = sif->subsys;
1056 :
1057 0 : mutex_lock(&subsys->p->mutex);
1058 0 : list_del_init(&sif->node);
1059 0 : if (sif->remove_dev) {
1060 : subsys_dev_iter_init(&iter, subsys, NULL, NULL);
1061 0 : while ((dev = subsys_dev_iter_next(&iter)))
1062 0 : sif->remove_dev(dev, sif);
1063 : subsys_dev_iter_exit(&iter);
1064 : }
1065 0 : mutex_unlock(&subsys->p->mutex);
1066 :
1067 0 : bus_put(subsys);
1068 : }
1069 : EXPORT_SYMBOL_GPL(subsys_interface_unregister);
1070 :
1071 0 : static void system_root_device_release(struct device *dev)
1072 : {
1073 0 : kfree(dev);
1074 0 : }
1075 :
1076 5 : static int subsys_register(struct bus_type *subsys,
1077 : const struct attribute_group **groups,
1078 : struct kobject *parent_of_root)
1079 : {
1080 : struct device *dev;
1081 : int err;
1082 :
1083 5 : err = bus_register(subsys);
1084 5 : if (err < 0)
1085 : return err;
1086 :
1087 5 : dev = kzalloc(sizeof(struct device), GFP_KERNEL);
1088 5 : if (!dev) {
1089 : err = -ENOMEM;
1090 : goto err_dev;
1091 : }
1092 :
1093 5 : err = dev_set_name(dev, "%s", subsys->name);
1094 5 : if (err < 0)
1095 : goto err_name;
1096 :
1097 5 : dev->kobj.parent = parent_of_root;
1098 5 : dev->groups = groups;
1099 5 : dev->release = system_root_device_release;
1100 :
1101 5 : err = device_register(dev);
1102 5 : if (err < 0)
1103 : goto err_dev_reg;
1104 :
1105 5 : subsys->dev_root = dev;
1106 5 : return 0;
1107 :
1108 : err_dev_reg:
1109 0 : put_device(dev);
1110 0 : dev = NULL;
1111 : err_name:
1112 0 : kfree(dev);
1113 : err_dev:
1114 0 : bus_unregister(subsys);
1115 0 : return err;
1116 : }
1117 :
1118 : /**
1119 : * subsys_system_register - register a subsystem at /sys/devices/system/
1120 : * @subsys: system subsystem
1121 : * @groups: default attributes for the root device
1122 : *
1123 : * All 'system' subsystems have a /sys/devices/system/<name> root device
1124 : * with the name of the subsystem. The root device can carry subsystem-
1125 : * wide attributes. All registered devices are below this single root
1126 : * device and are named after the subsystem with a simple enumeration
1127 : * number appended. The registered devices are not explicitly named;
1128 : * only 'id' in the device needs to be set.
1129 : *
1130 : * Do not use this interface for anything new, it exists for compatibility
1131 : * with bad ideas only. New subsystems should use plain subsystems; and
1132 : * add the subsystem-wide attributes should be added to the subsystem
1133 : * directory itself and not some create fake root-device placed in
1134 : * /sys/devices/system/<name>.
1135 : */
1136 4 : int subsys_system_register(struct bus_type *subsys,
1137 : const struct attribute_group **groups)
1138 : {
1139 4 : return subsys_register(subsys, groups, &system_kset->kobj);
1140 : }
1141 : EXPORT_SYMBOL_GPL(subsys_system_register);
1142 :
1143 : /**
1144 : * subsys_virtual_register - register a subsystem at /sys/devices/virtual/
1145 : * @subsys: virtual subsystem
1146 : * @groups: default attributes for the root device
1147 : *
1148 : * All 'virtual' subsystems have a /sys/devices/system/<name> root device
1149 : * with the name of the subystem. The root device can carry subsystem-wide
1150 : * attributes. All registered devices are below this single root device.
1151 : * There's no restriction on device naming. This is for kernel software
1152 : * constructs which need sysfs interface.
1153 : */
1154 1 : int subsys_virtual_register(struct bus_type *subsys,
1155 : const struct attribute_group **groups)
1156 : {
1157 : struct kobject *virtual_dir;
1158 :
1159 1 : virtual_dir = virtual_device_parent(NULL);
1160 1 : if (!virtual_dir)
1161 : return -ENOMEM;
1162 :
1163 1 : return subsys_register(subsys, groups, virtual_dir);
1164 : }
1165 : EXPORT_SYMBOL_GPL(subsys_virtual_register);
1166 :
1167 1 : int __init buses_init(void)
1168 : {
1169 1 : bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);
1170 1 : if (!bus_kset)
1171 : return -ENOMEM;
1172 :
1173 1 : system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);
1174 1 : if (!system_kset)
1175 : return -ENOMEM;
1176 :
1177 1 : return 0;
1178 : }
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