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 :
42 220 : static struct bus_type *bus_get(struct bus_type *bus)
43 : {
44 220 : if (bus) {
45 69 : kset_get(&bus->p->subsys);
46 0 : return bus;
47 : }
48 : return NULL;
49 : }
50 :
51 31 : static void bus_put(struct bus_type *bus)
52 : {
53 31 : if (bus)
54 1 : kset_put(&bus->p->subsys);
55 30 : }
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 14 : static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr,
70 : const char *buf, size_t count)
71 : {
72 14 : struct driver_attribute *drv_attr = to_drv_attr(attr);
73 14 : struct driver_private *drv_priv = to_driver(kobj);
74 14 : ssize_t ret = -EIO;
75 :
76 14 : if (drv_attr->store)
77 14 : ret = drv_attr->store(drv_priv->driver, buf, count);
78 14 : 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 1 : 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 10 : static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr,
115 : const char *buf, size_t count)
116 : {
117 10 : struct bus_attribute *bus_attr = to_bus_attr(attr);
118 10 : struct subsys_private *subsys_priv = to_subsys_private(kobj);
119 10 : ssize_t ret = 0;
120 :
121 10 : if (bus_attr->store)
122 10 : ret = bus_attr->store(subsys_priv->bus, buf, count);
123 10 : 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 30 : int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)
132 : {
133 30 : int error;
134 30 : if (bus_get(bus)) {
135 30 : error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);
136 30 : bus_put(bus);
137 : } else
138 : error = -EINVAL;
139 30 : 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 0 : 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 40 : static int bus_uevent_filter(struct kset *kset, struct kobject *kobj)
167 : {
168 40 : struct kobj_type *ktype = get_ktype(kobj);
169 :
170 40 : if (ktype == &bus_ktype)
171 20 : return 1;
172 : 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 0 : 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, S_IWUSR, 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 0 : struct device *dev;
210 0 : int err = -ENODEV;
211 :
212 0 : dev = bus_find_device_by_name(bus, NULL, buf);
213 0 : if (dev && dev->driver == NULL && driver_match_device(drv, dev)) {
214 0 : err = device_driver_attach(drv, dev);
215 :
216 0 : if (err > 0) {
217 : /* success */
218 0 : err = count;
219 0 : } else if (err == 0) {
220 : /* driver didn't accept device */
221 0 : err = -ENODEV;
222 : }
223 : }
224 0 : put_device(dev);
225 0 : bus_put(bus);
226 0 : return err;
227 : }
228 : static DRIVER_ATTR_IGNORE_LOCKDEP(bind, S_IWUSR, NULL, bind_store);
229 :
230 0 : static ssize_t drivers_autoprobe_show(struct bus_type *bus, char *buf)
231 : {
232 0 : return sysfs_emit(buf, "%d\n", bus->p->drivers_autoprobe);
233 : }
234 :
235 0 : static ssize_t drivers_autoprobe_store(struct bus_type *bus,
236 : const char *buf, size_t count)
237 : {
238 0 : if (buf[0] == '0')
239 0 : bus->p->drivers_autoprobe = 0;
240 : else
241 0 : bus->p->drivers_autoprobe = 1;
242 0 : return count;
243 : }
244 :
245 0 : static ssize_t drivers_probe_store(struct bus_type *bus,
246 : const char *buf, size_t count)
247 : {
248 0 : struct device *dev;
249 0 : int err = -EINVAL;
250 :
251 0 : dev = bus_find_device_by_name(bus, NULL, buf);
252 0 : if (!dev)
253 : return -ENODEV;
254 0 : if (bus_rescan_devices_helper(dev, NULL) == 0)
255 0 : err = count;
256 0 : put_device(dev);
257 0 : return err;
258 : }
259 :
260 51 : static struct device *next_device(struct klist_iter *i)
261 : {
262 51 : struct klist_node *n = klist_next(i);
263 51 : struct device *dev = NULL;
264 51 : struct device_private *dev_prv;
265 :
266 51 : if (n) {
267 36 : dev_prv = to_device_private_bus(n);
268 36 : dev = dev_prv->device;
269 : }
270 36 : return dev;
271 : }
272 :
273 : /**
274 : * bus_for_each_dev - device iterator.
275 : * @bus: bus type.
276 : * @start: device to start iterating from.
277 : * @data: data for the callback.
278 : * @fn: function to be called for each device.
279 : *
280 : * Iterate over @bus's list of devices, and call @fn for each,
281 : * passing it @data. If @start is not NULL, we use that device to
282 : * begin iterating from.
283 : *
284 : * We check the return of @fn each time. If it returns anything
285 : * other than 0, we break out and return that value.
286 : *
287 : * NOTE: The device that returns a non-zero value is not retained
288 : * in any way, nor is its refcount incremented. If the caller needs
289 : * to retain this data, it should do so, and increment the reference
290 : * count in the supplied callback.
291 : */
292 15 : int bus_for_each_dev(struct bus_type *bus, struct device *start,
293 : void *data, int (*fn)(struct device *, void *))
294 : {
295 15 : struct klist_iter i;
296 15 : struct device *dev;
297 15 : int error = 0;
298 :
299 15 : if (!bus || !bus->p)
300 : return -EINVAL;
301 :
302 15 : klist_iter_init_node(&bus->p->klist_devices, &i,
303 0 : (start ? &start->p->knode_bus : NULL));
304 87 : while (!error && (dev = next_device(&i)))
305 36 : error = fn(dev, data);
306 15 : klist_iter_exit(&i);
307 15 : return error;
308 : }
309 : EXPORT_SYMBOL_GPL(bus_for_each_dev);
310 :
311 : /**
312 : * bus_find_device - device iterator for locating a particular device.
313 : * @bus: bus type
314 : * @start: Device to begin with
315 : * @data: Data to pass to match function
316 : * @match: Callback function to check device
317 : *
318 : * This is similar to the bus_for_each_dev() function above, but it
319 : * returns a reference to a device that is 'found' for later use, as
320 : * determined by the @match callback.
321 : *
322 : * The callback should return 0 if the device doesn't match and non-zero
323 : * if it does. If the callback returns non-zero, this function will
324 : * return to the caller and not iterate over any more devices.
325 : */
326 0 : struct device *bus_find_device(struct bus_type *bus,
327 : struct device *start, const void *data,
328 : int (*match)(struct device *dev, const void *data))
329 : {
330 0 : struct klist_iter i;
331 0 : struct device *dev;
332 :
333 0 : if (!bus || !bus->p)
334 : return NULL;
335 :
336 0 : klist_iter_init_node(&bus->p->klist_devices, &i,
337 0 : (start ? &start->p->knode_bus : NULL));
338 0 : while ((dev = next_device(&i)))
339 0 : if (match(dev, data) && get_device(dev))
340 : break;
341 0 : klist_iter_exit(&i);
342 0 : return dev;
343 : }
344 : EXPORT_SYMBOL_GPL(bus_find_device);
345 :
346 : /**
347 : * subsys_find_device_by_id - find a device with a specific enumeration number
348 : * @subsys: subsystem
349 : * @id: index 'id' in struct device
350 : * @hint: device to check first
351 : *
352 : * Check the hint's next object and if it is a match return it directly,
353 : * otherwise, fall back to a full list search. Either way a reference for
354 : * the returned object is taken.
355 : */
356 0 : struct device *subsys_find_device_by_id(struct bus_type *subsys, unsigned int id,
357 : struct device *hint)
358 : {
359 0 : struct klist_iter i;
360 0 : struct device *dev;
361 :
362 0 : if (!subsys)
363 : return NULL;
364 :
365 0 : if (hint) {
366 0 : klist_iter_init_node(&subsys->p->klist_devices, &i, &hint->p->knode_bus);
367 0 : dev = next_device(&i);
368 0 : if (dev && dev->id == id && get_device(dev)) {
369 0 : klist_iter_exit(&i);
370 0 : return dev;
371 : }
372 0 : klist_iter_exit(&i);
373 : }
374 :
375 0 : klist_iter_init_node(&subsys->p->klist_devices, &i, NULL);
376 0 : while ((dev = next_device(&i))) {
377 0 : if (dev->id == id && get_device(dev)) {
378 0 : klist_iter_exit(&i);
379 0 : return dev;
380 : }
381 : }
382 0 : klist_iter_exit(&i);
383 0 : return NULL;
384 : }
385 : EXPORT_SYMBOL_GPL(subsys_find_device_by_id);
386 :
387 26 : static struct device_driver *next_driver(struct klist_iter *i)
388 : {
389 52 : struct klist_node *n = klist_next(i);
390 26 : struct driver_private *drv_priv;
391 :
392 26 : if (n) {
393 2 : drv_priv = container_of(n, struct driver_private, knode_bus);
394 2 : return drv_priv->driver;
395 : }
396 : return NULL;
397 : }
398 :
399 : /**
400 : * bus_for_each_drv - driver iterator
401 : * @bus: bus we're dealing with.
402 : * @start: driver to start iterating on.
403 : * @data: data to pass to the callback.
404 : * @fn: function to call for each driver.
405 : *
406 : * This is nearly identical to the device iterator above.
407 : * We iterate over each driver that belongs to @bus, and call
408 : * @fn for each. If @fn returns anything but 0, we break out
409 : * and return it. If @start is not NULL, we use it as the head
410 : * of the list.
411 : *
412 : * NOTE: we don't return the driver that returns a non-zero
413 : * value, nor do we leave the reference count incremented for that
414 : * driver. If the caller needs to know that info, it must set it
415 : * in the callback. It must also be sure to increment the refcount
416 : * so it doesn't disappear before returning to the caller.
417 : */
418 24 : int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
419 : void *data, int (*fn)(struct device_driver *, void *))
420 : {
421 24 : struct klist_iter i;
422 24 : struct device_driver *drv;
423 24 : int error = 0;
424 :
425 24 : if (!bus)
426 : return -EINVAL;
427 :
428 24 : klist_iter_init_node(&bus->p->klist_drivers, &i,
429 0 : start ? &start->p->knode_bus : NULL);
430 28 : while ((drv = next_driver(&i)) && !error)
431 2 : error = fn(drv, data);
432 24 : klist_iter_exit(&i);
433 24 : return error;
434 : }
435 : EXPORT_SYMBOL_GPL(bus_for_each_drv);
436 :
437 : /**
438 : * bus_add_device - add device to bus
439 : * @dev: device being added
440 : *
441 : * - Add device's bus attributes.
442 : * - Create links to device's bus.
443 : * - Add the device to its bus's list of devices.
444 : */
445 175 : int bus_add_device(struct device *dev)
446 : {
447 175 : struct bus_type *bus = bus_get(dev->bus);
448 199 : int error = 0;
449 :
450 24 : if (bus) {
451 24 : pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev));
452 24 : error = device_add_groups(dev, bus->dev_groups);
453 24 : if (error)
454 0 : goto out_put;
455 48 : error = sysfs_create_link(&bus->p->devices_kset->kobj,
456 : &dev->kobj, dev_name(dev));
457 24 : if (error)
458 0 : goto out_groups;
459 48 : error = sysfs_create_link(&dev->kobj,
460 24 : &dev->bus->p->subsys.kobj, "subsystem");
461 24 : if (error)
462 0 : goto out_subsys;
463 24 : klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);
464 : }
465 : return 0;
466 :
467 0 : out_subsys:
468 0 : sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev));
469 0 : out_groups:
470 0 : device_remove_groups(dev, bus->dev_groups);
471 0 : out_put:
472 0 : bus_put(dev->bus);
473 : return error;
474 : }
475 :
476 : /**
477 : * bus_probe_device - probe drivers for a new device
478 : * @dev: device to probe
479 : *
480 : * - Automatically probe for a driver if the bus allows it.
481 : */
482 175 : void bus_probe_device(struct device *dev)
483 : {
484 175 : struct bus_type *bus = dev->bus;
485 175 : struct subsys_interface *sif;
486 :
487 175 : if (!bus)
488 : return;
489 :
490 24 : if (bus->p->drivers_autoprobe)
491 24 : device_initial_probe(dev);
492 :
493 24 : mutex_lock(&bus->p->mutex);
494 24 : list_for_each_entry(sif, &bus->p->interfaces, node)
495 0 : if (sif->add_dev)
496 0 : sif->add_dev(dev, sif);
497 24 : mutex_unlock(&bus->p->mutex);
498 : }
499 :
500 : /**
501 : * bus_remove_device - remove device from bus
502 : * @dev: device to be removed
503 : *
504 : * - Remove device from all interfaces.
505 : * - Remove symlink from bus' directory.
506 : * - Delete device from bus's list.
507 : * - Detach from its driver.
508 : * - Drop reference taken in bus_add_device().
509 : */
510 0 : void bus_remove_device(struct device *dev)
511 : {
512 0 : struct bus_type *bus = dev->bus;
513 0 : struct subsys_interface *sif;
514 :
515 0 : if (!bus)
516 : return;
517 :
518 0 : mutex_lock(&bus->p->mutex);
519 0 : list_for_each_entry(sif, &bus->p->interfaces, node)
520 0 : if (sif->remove_dev)
521 0 : sif->remove_dev(dev, sif);
522 0 : mutex_unlock(&bus->p->mutex);
523 :
524 0 : sysfs_remove_link(&dev->kobj, "subsystem");
525 0 : sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
526 : dev_name(dev));
527 0 : device_remove_groups(dev, dev->bus->dev_groups);
528 0 : if (klist_node_attached(&dev->p->knode_bus))
529 0 : klist_del(&dev->p->knode_bus);
530 :
531 0 : pr_debug("bus: '%s': remove device %s\n",
532 : dev->bus->name, dev_name(dev));
533 0 : device_release_driver(dev);
534 0 : bus_put(dev->bus);
535 : }
536 :
537 14 : static int __must_check add_bind_files(struct device_driver *drv)
538 : {
539 14 : int ret;
540 :
541 14 : ret = driver_create_file(drv, &driver_attr_unbind);
542 14 : if (ret == 0) {
543 14 : ret = driver_create_file(drv, &driver_attr_bind);
544 14 : if (ret)
545 0 : driver_remove_file(drv, &driver_attr_unbind);
546 : }
547 14 : return ret;
548 : }
549 :
550 0 : static void remove_bind_files(struct device_driver *drv)
551 : {
552 0 : driver_remove_file(drv, &driver_attr_bind);
553 0 : driver_remove_file(drv, &driver_attr_unbind);
554 0 : }
555 :
556 : static BUS_ATTR_WO(drivers_probe);
557 : static BUS_ATTR_RW(drivers_autoprobe);
558 :
559 10 : static int add_probe_files(struct bus_type *bus)
560 : {
561 10 : int retval;
562 :
563 10 : retval = bus_create_file(bus, &bus_attr_drivers_probe);
564 10 : if (retval)
565 0 : goto out;
566 :
567 10 : retval = bus_create_file(bus, &bus_attr_drivers_autoprobe);
568 10 : if (retval)
569 0 : bus_remove_file(bus, &bus_attr_drivers_probe);
570 10 : out:
571 10 : return retval;
572 : }
573 :
574 0 : static void remove_probe_files(struct bus_type *bus)
575 : {
576 0 : bus_remove_file(bus, &bus_attr_drivers_autoprobe);
577 0 : bus_remove_file(bus, &bus_attr_drivers_probe);
578 0 : }
579 :
580 14 : static ssize_t uevent_store(struct device_driver *drv, const char *buf,
581 : size_t count)
582 : {
583 14 : int rc;
584 :
585 14 : rc = kobject_synth_uevent(&drv->p->kobj, buf, count);
586 14 : return rc ? rc : count;
587 : }
588 : static DRIVER_ATTR_WO(uevent);
589 :
590 : /**
591 : * bus_add_driver - Add a driver to the bus.
592 : * @drv: driver.
593 : */
594 15 : int bus_add_driver(struct device_driver *drv)
595 : {
596 15 : struct bus_type *bus;
597 15 : struct driver_private *priv;
598 15 : int error = 0;
599 :
600 15 : bus = bus_get(drv->bus);
601 15 : if (!bus)
602 : return -EINVAL;
603 :
604 15 : pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name);
605 :
606 15 : priv = kzalloc(sizeof(*priv), GFP_KERNEL);
607 15 : if (!priv) {
608 0 : error = -ENOMEM;
609 0 : goto out_put_bus;
610 : }
611 15 : klist_init(&priv->klist_devices, NULL, NULL);
612 15 : priv->driver = drv;
613 15 : drv->p = priv;
614 15 : priv->kobj.kset = bus->p->drivers_kset;
615 15 : error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL,
616 : "%s", drv->name);
617 15 : if (error)
618 0 : goto out_unregister;
619 :
620 15 : klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);
621 15 : if (drv->bus->p->drivers_autoprobe) {
622 15 : error = driver_attach(drv);
623 15 : if (error)
624 0 : goto out_unregister;
625 : }
626 15 : module_add_driver(drv->owner, drv);
627 :
628 15 : error = driver_create_file(drv, &driver_attr_uevent);
629 15 : if (error) {
630 0 : printk(KERN_ERR "%s: uevent attr (%s) failed\n",
631 : __func__, drv->name);
632 : }
633 15 : error = driver_add_groups(drv, bus->drv_groups);
634 15 : if (error) {
635 : /* How the hell do we get out of this pickle? Give up */
636 0 : printk(KERN_ERR "%s: driver_add_groups(%s) failed\n",
637 : __func__, drv->name);
638 : }
639 :
640 15 : if (!drv->suppress_bind_attrs) {
641 14 : error = add_bind_files(drv);
642 14 : if (error) {
643 : /* Ditto */
644 0 : printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
645 : __func__, drv->name);
646 : }
647 : }
648 :
649 : return 0;
650 :
651 0 : out_unregister:
652 0 : kobject_put(&priv->kobj);
653 : /* drv->p is freed in driver_release() */
654 0 : drv->p = NULL;
655 0 : out_put_bus:
656 0 : bus_put(bus);
657 0 : return error;
658 : }
659 :
660 : /**
661 : * bus_remove_driver - delete driver from bus's knowledge.
662 : * @drv: driver.
663 : *
664 : * Detach the driver from the devices it controls, and remove
665 : * it from its bus's list of drivers. Finally, we drop the reference
666 : * to the bus we took in bus_add_driver().
667 : */
668 1 : void bus_remove_driver(struct device_driver *drv)
669 : {
670 1 : if (!drv->bus)
671 : return;
672 :
673 1 : if (!drv->suppress_bind_attrs)
674 0 : remove_bind_files(drv);
675 1 : driver_remove_groups(drv, drv->bus->drv_groups);
676 1 : driver_remove_file(drv, &driver_attr_uevent);
677 1 : klist_remove(&drv->p->knode_bus);
678 1 : pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name);
679 1 : driver_detach(drv);
680 1 : module_remove_driver(drv);
681 1 : kobject_put(&drv->p->kobj);
682 1 : bus_put(drv->bus);
683 : }
684 :
685 : /* Helper for bus_rescan_devices's iter */
686 0 : static int __must_check bus_rescan_devices_helper(struct device *dev,
687 : void *data)
688 : {
689 0 : int ret = 0;
690 :
691 0 : if (!dev->driver) {
692 0 : if (dev->parent && dev->bus->need_parent_lock)
693 0 : device_lock(dev->parent);
694 0 : ret = device_attach(dev);
695 0 : if (dev->parent && dev->bus->need_parent_lock)
696 0 : device_unlock(dev->parent);
697 : }
698 0 : return ret < 0 ? ret : 0;
699 : }
700 :
701 : /**
702 : * bus_rescan_devices - rescan devices on the bus for possible drivers
703 : * @bus: the bus to scan.
704 : *
705 : * This function will look for devices on the bus with no driver
706 : * attached and rescan it against existing drivers to see if it matches
707 : * any by calling device_attach() for the unbound devices.
708 : */
709 0 : int bus_rescan_devices(struct bus_type *bus)
710 : {
711 0 : return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
712 : }
713 : EXPORT_SYMBOL_GPL(bus_rescan_devices);
714 :
715 : /**
716 : * device_reprobe - remove driver for a device and probe for a new driver
717 : * @dev: the device to reprobe
718 : *
719 : * This function detaches the attached driver (if any) for the given
720 : * device and restarts the driver probing process. It is intended
721 : * to use if probing criteria changed during a devices lifetime and
722 : * driver attachment should change accordingly.
723 : */
724 0 : int device_reprobe(struct device *dev)
725 : {
726 0 : if (dev->driver)
727 0 : device_driver_detach(dev);
728 0 : return bus_rescan_devices_helper(dev, NULL);
729 : }
730 : EXPORT_SYMBOL_GPL(device_reprobe);
731 :
732 10 : static int bus_add_groups(struct bus_type *bus,
733 : const struct attribute_group **groups)
734 : {
735 10 : return sysfs_create_groups(&bus->p->subsys.kobj, groups);
736 : }
737 :
738 0 : static void bus_remove_groups(struct bus_type *bus,
739 : const struct attribute_group **groups)
740 : {
741 0 : sysfs_remove_groups(&bus->p->subsys.kobj, groups);
742 : }
743 :
744 24 : static void klist_devices_get(struct klist_node *n)
745 : {
746 24 : struct device_private *dev_prv = to_device_private_bus(n);
747 24 : struct device *dev = dev_prv->device;
748 :
749 24 : get_device(dev);
750 24 : }
751 :
752 0 : static void klist_devices_put(struct klist_node *n)
753 : {
754 0 : struct device_private *dev_prv = to_device_private_bus(n);
755 0 : struct device *dev = dev_prv->device;
756 :
757 0 : put_device(dev);
758 0 : }
759 :
760 10 : static ssize_t bus_uevent_store(struct bus_type *bus,
761 : const char *buf, size_t count)
762 : {
763 10 : int rc;
764 :
765 10 : rc = kobject_synth_uevent(&bus->p->subsys.kobj, buf, count);
766 10 : return rc ? rc : count;
767 : }
768 : /*
769 : * "open code" the old BUS_ATTR() macro here. We want to use BUS_ATTR_WO()
770 : * here, but can not use it as earlier in the file we have
771 : * DEVICE_ATTR_WO(uevent), which would cause a clash with the with the store
772 : * function name.
773 : */
774 : static struct bus_attribute bus_attr_uevent = __ATTR(uevent, S_IWUSR, NULL,
775 : bus_uevent_store);
776 :
777 : /**
778 : * bus_register - register a driver-core subsystem
779 : * @bus: bus to register
780 : *
781 : * Once we have that, we register the bus with the kobject
782 : * infrastructure, then register the children subsystems it has:
783 : * the devices and drivers that belong to the subsystem.
784 : */
785 10 : int bus_register(struct bus_type *bus)
786 : {
787 10 : int retval;
788 10 : struct subsys_private *priv;
789 10 : struct lock_class_key *key = &bus->lock_key;
790 :
791 10 : priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL);
792 10 : if (!priv)
793 : return -ENOMEM;
794 :
795 10 : priv->bus = bus;
796 10 : bus->p = priv;
797 :
798 10 : BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier);
799 :
800 10 : retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);
801 10 : if (retval)
802 0 : goto out;
803 :
804 10 : priv->subsys.kobj.kset = bus_kset;
805 10 : priv->subsys.kobj.ktype = &bus_ktype;
806 10 : priv->drivers_autoprobe = 1;
807 :
808 10 : retval = kset_register(&priv->subsys);
809 10 : if (retval)
810 0 : goto out;
811 :
812 10 : retval = bus_create_file(bus, &bus_attr_uevent);
813 10 : if (retval)
814 0 : goto bus_uevent_fail;
815 :
816 10 : priv->devices_kset = kset_create_and_add("devices", NULL,
817 : &priv->subsys.kobj);
818 10 : if (!priv->devices_kset) {
819 0 : retval = -ENOMEM;
820 0 : goto bus_devices_fail;
821 : }
822 :
823 10 : priv->drivers_kset = kset_create_and_add("drivers", NULL,
824 : &priv->subsys.kobj);
825 10 : if (!priv->drivers_kset) {
826 0 : retval = -ENOMEM;
827 0 : goto bus_drivers_fail;
828 : }
829 :
830 10 : INIT_LIST_HEAD(&priv->interfaces);
831 10 : __mutex_init(&priv->mutex, "subsys mutex", key);
832 10 : klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put);
833 10 : klist_init(&priv->klist_drivers, NULL, NULL);
834 :
835 10 : retval = add_probe_files(bus);
836 10 : if (retval)
837 0 : goto bus_probe_files_fail;
838 :
839 10 : retval = bus_add_groups(bus, bus->bus_groups);
840 10 : if (retval)
841 0 : goto bus_groups_fail;
842 :
843 : pr_debug("bus: '%s': registered\n", bus->name);
844 : return 0;
845 :
846 0 : bus_groups_fail:
847 0 : remove_probe_files(bus);
848 0 : bus_probe_files_fail:
849 0 : kset_unregister(bus->p->drivers_kset);
850 0 : bus_drivers_fail:
851 0 : kset_unregister(bus->p->devices_kset);
852 0 : bus_devices_fail:
853 0 : bus_remove_file(bus, &bus_attr_uevent);
854 0 : bus_uevent_fail:
855 0 : kset_unregister(&bus->p->subsys);
856 0 : out:
857 0 : kfree(bus->p);
858 0 : bus->p = NULL;
859 0 : return retval;
860 : }
861 : EXPORT_SYMBOL_GPL(bus_register);
862 :
863 : /**
864 : * bus_unregister - remove a bus from the system
865 : * @bus: bus.
866 : *
867 : * Unregister the child subsystems and the bus itself.
868 : * Finally, we call bus_put() to release the refcount
869 : */
870 0 : void bus_unregister(struct bus_type *bus)
871 : {
872 0 : pr_debug("bus: '%s': unregistering\n", bus->name);
873 0 : if (bus->dev_root)
874 0 : device_unregister(bus->dev_root);
875 0 : bus_remove_groups(bus, bus->bus_groups);
876 0 : remove_probe_files(bus);
877 0 : kset_unregister(bus->p->drivers_kset);
878 0 : kset_unregister(bus->p->devices_kset);
879 0 : bus_remove_file(bus, &bus_attr_uevent);
880 0 : kset_unregister(&bus->p->subsys);
881 0 : }
882 : EXPORT_SYMBOL_GPL(bus_unregister);
883 :
884 0 : int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
885 : {
886 0 : return blocking_notifier_chain_register(&bus->p->bus_notifier, nb);
887 : }
888 : EXPORT_SYMBOL_GPL(bus_register_notifier);
889 :
890 0 : int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
891 : {
892 0 : return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb);
893 : }
894 : EXPORT_SYMBOL_GPL(bus_unregister_notifier);
895 :
896 0 : struct kset *bus_get_kset(struct bus_type *bus)
897 : {
898 0 : return &bus->p->subsys;
899 : }
900 : EXPORT_SYMBOL_GPL(bus_get_kset);
901 :
902 0 : struct klist *bus_get_device_klist(struct bus_type *bus)
903 : {
904 0 : return &bus->p->klist_devices;
905 : }
906 : EXPORT_SYMBOL_GPL(bus_get_device_klist);
907 :
908 : /*
909 : * Yes, this forcibly breaks the klist abstraction temporarily. It
910 : * just wants to sort the klist, not change reference counts and
911 : * take/drop locks rapidly in the process. It does all this while
912 : * holding the lock for the list, so objects can't otherwise be
913 : * added/removed while we're swizzling.
914 : */
915 0 : static void device_insertion_sort_klist(struct device *a, struct list_head *list,
916 : int (*compare)(const struct device *a,
917 : const struct device *b))
918 : {
919 0 : struct klist_node *n;
920 0 : struct device_private *dev_prv;
921 0 : struct device *b;
922 :
923 0 : list_for_each_entry(n, list, n_node) {
924 0 : dev_prv = to_device_private_bus(n);
925 0 : b = dev_prv->device;
926 0 : if (compare(a, b) <= 0) {
927 0 : list_move_tail(&a->p->knode_bus.n_node,
928 0 : &b->p->knode_bus.n_node);
929 0 : return;
930 : }
931 : }
932 0 : list_move_tail(&a->p->knode_bus.n_node, list);
933 : }
934 :
935 0 : void bus_sort_breadthfirst(struct bus_type *bus,
936 : int (*compare)(const struct device *a,
937 : const struct device *b))
938 : {
939 0 : LIST_HEAD(sorted_devices);
940 0 : struct klist_node *n, *tmp;
941 0 : struct device_private *dev_prv;
942 0 : struct device *dev;
943 0 : struct klist *device_klist;
944 :
945 0 : device_klist = bus_get_device_klist(bus);
946 :
947 0 : spin_lock(&device_klist->k_lock);
948 0 : list_for_each_entry_safe(n, tmp, &device_klist->k_list, n_node) {
949 0 : dev_prv = to_device_private_bus(n);
950 0 : dev = dev_prv->device;
951 0 : device_insertion_sort_klist(dev, &sorted_devices, compare);
952 : }
953 0 : list_splice(&sorted_devices, &device_klist->k_list);
954 0 : spin_unlock(&device_klist->k_lock);
955 0 : }
956 : EXPORT_SYMBOL_GPL(bus_sort_breadthfirst);
957 :
958 : /**
959 : * subsys_dev_iter_init - initialize subsys device iterator
960 : * @iter: subsys iterator to initialize
961 : * @subsys: the subsys we wanna iterate over
962 : * @start: the device to start iterating from, if any
963 : * @type: device_type of the devices to iterate over, NULL for all
964 : *
965 : * Initialize subsys iterator @iter such that it iterates over devices
966 : * of @subsys. If @start is set, the list iteration will start there,
967 : * otherwise if it is NULL, the iteration starts at the beginning of
968 : * the list.
969 : */
970 0 : void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct bus_type *subsys,
971 : struct device *start, const struct device_type *type)
972 : {
973 0 : struct klist_node *start_knode = NULL;
974 :
975 0 : if (start)
976 0 : start_knode = &start->p->knode_bus;
977 0 : klist_iter_init_node(&subsys->p->klist_devices, &iter->ki, start_knode);
978 0 : iter->type = type;
979 0 : }
980 : EXPORT_SYMBOL_GPL(subsys_dev_iter_init);
981 :
982 : /**
983 : * subsys_dev_iter_next - iterate to the next device
984 : * @iter: subsys iterator to proceed
985 : *
986 : * Proceed @iter to the next device and return it. Returns NULL if
987 : * iteration is complete.
988 : *
989 : * The returned device is referenced and won't be released till
990 : * iterator is proceed to the next device or exited. The caller is
991 : * free to do whatever it wants to do with the device including
992 : * calling back into subsys code.
993 : */
994 0 : struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter)
995 : {
996 0 : struct klist_node *knode;
997 0 : struct device *dev;
998 :
999 0 : for (;;) {
1000 0 : knode = klist_next(&iter->ki);
1001 0 : if (!knode)
1002 : return NULL;
1003 0 : dev = to_device_private_bus(knode)->device;
1004 0 : if (!iter->type || iter->type == dev->type)
1005 0 : return dev;
1006 : }
1007 : }
1008 : EXPORT_SYMBOL_GPL(subsys_dev_iter_next);
1009 :
1010 : /**
1011 : * subsys_dev_iter_exit - finish iteration
1012 : * @iter: subsys iterator to finish
1013 : *
1014 : * Finish an iteration. Always call this function after iteration is
1015 : * complete whether the iteration ran till the end or not.
1016 : */
1017 0 : void subsys_dev_iter_exit(struct subsys_dev_iter *iter)
1018 : {
1019 0 : klist_iter_exit(&iter->ki);
1020 0 : }
1021 : EXPORT_SYMBOL_GPL(subsys_dev_iter_exit);
1022 :
1023 0 : int subsys_interface_register(struct subsys_interface *sif)
1024 : {
1025 0 : struct bus_type *subsys;
1026 0 : struct subsys_dev_iter iter;
1027 0 : struct device *dev;
1028 :
1029 0 : if (!sif || !sif->subsys)
1030 : return -ENODEV;
1031 :
1032 0 : subsys = bus_get(sif->subsys);
1033 0 : if (!subsys)
1034 : return -EINVAL;
1035 :
1036 0 : mutex_lock(&subsys->p->mutex);
1037 0 : list_add_tail(&sif->node, &subsys->p->interfaces);
1038 0 : if (sif->add_dev) {
1039 0 : subsys_dev_iter_init(&iter, subsys, NULL, NULL);
1040 0 : while ((dev = subsys_dev_iter_next(&iter)))
1041 0 : sif->add_dev(dev, sif);
1042 0 : subsys_dev_iter_exit(&iter);
1043 : }
1044 0 : mutex_unlock(&subsys->p->mutex);
1045 :
1046 0 : return 0;
1047 : }
1048 : EXPORT_SYMBOL_GPL(subsys_interface_register);
1049 :
1050 0 : void subsys_interface_unregister(struct subsys_interface *sif)
1051 : {
1052 0 : struct bus_type *subsys;
1053 0 : struct subsys_dev_iter iter;
1054 0 : struct device *dev;
1055 :
1056 0 : if (!sif || !sif->subsys)
1057 0 : return;
1058 :
1059 0 : subsys = sif->subsys;
1060 :
1061 0 : mutex_lock(&subsys->p->mutex);
1062 0 : list_del_init(&sif->node);
1063 0 : if (sif->remove_dev) {
1064 0 : subsys_dev_iter_init(&iter, subsys, NULL, NULL);
1065 0 : while ((dev = subsys_dev_iter_next(&iter)))
1066 0 : sif->remove_dev(dev, sif);
1067 0 : subsys_dev_iter_exit(&iter);
1068 : }
1069 0 : mutex_unlock(&subsys->p->mutex);
1070 :
1071 0 : bus_put(subsys);
1072 : }
1073 : EXPORT_SYMBOL_GPL(subsys_interface_unregister);
1074 :
1075 0 : static void system_root_device_release(struct device *dev)
1076 : {
1077 0 : kfree(dev);
1078 0 : }
1079 :
1080 6 : static int subsys_register(struct bus_type *subsys,
1081 : const struct attribute_group **groups,
1082 : struct kobject *parent_of_root)
1083 : {
1084 6 : struct device *dev;
1085 6 : int err;
1086 :
1087 6 : err = bus_register(subsys);
1088 6 : if (err < 0)
1089 : return err;
1090 :
1091 6 : dev = kzalloc(sizeof(struct device), GFP_KERNEL);
1092 6 : if (!dev) {
1093 0 : err = -ENOMEM;
1094 0 : goto err_dev;
1095 : }
1096 :
1097 6 : err = dev_set_name(dev, "%s", subsys->name);
1098 6 : if (err < 0)
1099 0 : goto err_name;
1100 :
1101 6 : dev->kobj.parent = parent_of_root;
1102 6 : dev->groups = groups;
1103 6 : dev->release = system_root_device_release;
1104 :
1105 6 : err = device_register(dev);
1106 6 : if (err < 0)
1107 0 : goto err_dev_reg;
1108 :
1109 6 : subsys->dev_root = dev;
1110 6 : return 0;
1111 :
1112 0 : err_dev_reg:
1113 0 : put_device(dev);
1114 0 : dev = NULL;
1115 0 : err_name:
1116 0 : kfree(dev);
1117 0 : err_dev:
1118 0 : bus_unregister(subsys);
1119 0 : return err;
1120 : }
1121 :
1122 : /**
1123 : * subsys_system_register - register a subsystem at /sys/devices/system/
1124 : * @subsys: system subsystem
1125 : * @groups: default attributes for the root device
1126 : *
1127 : * All 'system' subsystems have a /sys/devices/system/<name> root device
1128 : * with the name of the subsystem. The root device can carry subsystem-
1129 : * wide attributes. All registered devices are below this single root
1130 : * device and are named after the subsystem with a simple enumeration
1131 : * number appended. The registered devices are not explicitly named;
1132 : * only 'id' in the device needs to be set.
1133 : *
1134 : * Do not use this interface for anything new, it exists for compatibility
1135 : * with bad ideas only. New subsystems should use plain subsystems; and
1136 : * add the subsystem-wide attributes should be added to the subsystem
1137 : * directory itself and not some create fake root-device placed in
1138 : * /sys/devices/system/<name>.
1139 : */
1140 5 : int subsys_system_register(struct bus_type *subsys,
1141 : const struct attribute_group **groups)
1142 : {
1143 5 : return subsys_register(subsys, groups, &system_kset->kobj);
1144 : }
1145 : EXPORT_SYMBOL_GPL(subsys_system_register);
1146 :
1147 : /**
1148 : * subsys_virtual_register - register a subsystem at /sys/devices/virtual/
1149 : * @subsys: virtual subsystem
1150 : * @groups: default attributes for the root device
1151 : *
1152 : * All 'virtual' subsystems have a /sys/devices/system/<name> root device
1153 : * with the name of the subystem. The root device can carry subsystem-wide
1154 : * attributes. All registered devices are below this single root device.
1155 : * There's no restriction on device naming. This is for kernel software
1156 : * constructs which need sysfs interface.
1157 : */
1158 1 : int subsys_virtual_register(struct bus_type *subsys,
1159 : const struct attribute_group **groups)
1160 : {
1161 1 : struct kobject *virtual_dir;
1162 :
1163 1 : virtual_dir = virtual_device_parent(NULL);
1164 1 : if (!virtual_dir)
1165 : return -ENOMEM;
1166 :
1167 1 : return subsys_register(subsys, groups, virtual_dir);
1168 : }
1169 : EXPORT_SYMBOL_GPL(subsys_virtual_register);
1170 :
1171 1 : int __init buses_init(void)
1172 : {
1173 1 : bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);
1174 1 : if (!bus_kset)
1175 : return -ENOMEM;
1176 :
1177 1 : system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);
1178 1 : if (!system_kset)
1179 0 : return -ENOMEM;
1180 :
1181 : return 0;
1182 : }
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