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1 /*
2 * drivers/base/dd.c - The core device/driver interactions.
3 *
4 * This file contains the (sometimes tricky) code that controls the
5 * interactions between devices and drivers, which primarily includes
6 * driver binding and unbinding.
7 *
8 * All of this code used to exist in drivers/base/bus.c, but was
9 * relocated to here in the name of compartmentalization (since it wasn't
10 * strictly code just for the 'struct bus_type'.
11 *
12 * Copyright (c) 2002-5 Patrick Mochel
13 * Copyright (c) 2002-3 Open Source Development Labs
14 * Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de>
15 * Copyright (c) 2007-2009 Novell Inc.
16 *
17 * This file is released under the GPLv2
18 */
19
20 #include <linux/device.h>
21 #include <linux/delay.h>
22 #include <linux/module.h>
23 #include <linux/kthread.h>
24 #include <linux/wait.h>
25 #include <linux/async.h>
26 #include <linux/pm_runtime.h>
27 #include <linux/pinctrl/devinfo.h>
28
29 #include "base.h"
30 #include "power/power.h"
31
32 /*
33 * Deferred Probe infrastructure.
34 *
35 * Sometimes driver probe order matters, but the kernel doesn't always have
36 * dependency information which means some drivers will get probed before a
37 * resource it depends on is available. For example, an SDHCI driver may
38 * first need a GPIO line from an i2c GPIO controller before it can be
39 * initialized. If a required resource is not available yet, a driver can
40 * request probing to be deferred by returning -EPROBE_DEFER from its probe hook
41 *
42 * Deferred probe maintains two lists of devices, a pending list and an active
43 * list. A driver returning -EPROBE_DEFER causes the device to be added to the
44 * pending list. A successful driver probe will trigger moving all devices
45 * from the pending to the active list so that the workqueue will eventually
46 * retry them.
47 *
48 * The deferred_probe_mutex must be held any time the deferred_probe_*_list
49 * of the (struct device*)->p->deferred_probe pointers are manipulated
50 */
51 static DEFINE_MUTEX(deferred_probe_mutex);
52 static LIST_HEAD(deferred_probe_pending_list);
53 static LIST_HEAD(deferred_probe_active_list);
54 static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
55
56 /*
57 * In some cases, like suspend to RAM or hibernation, It might be reasonable
58 * to prohibit probing of devices as it could be unsafe.
59 * Once defer_all_probes is true all drivers probes will be forcibly deferred.
60 */
61 static bool defer_all_probes;
62
63 /*
64 * deferred_probe_work_func() - Retry probing devices in the active list.
65 */
66 static void deferred_probe_work_func(struct work_struct *work)
67 {
68 struct device *dev;
69 struct device_private *private;
70 /*
71 * This block processes every device in the deferred 'active' list.
72 * Each device is removed from the active list and passed to
73 * bus_probe_device() to re-attempt the probe. The loop continues
74 * until every device in the active list is removed and retried.
75 *
76 * Note: Once the device is removed from the list and the mutex is
77 * released, it is possible for the device get freed by another thread
78 * and cause a illegal pointer dereference. This code uses
79 * get/put_device() to ensure the device structure cannot disappear
80 * from under our feet.
81 */
82 mutex_lock(&deferred_probe_mutex);
83 while (!list_empty(&deferred_probe_active_list)) {
84 private = list_first_entry(&deferred_probe_active_list,
85 typeof(*dev->p), deferred_probe);
86 dev = private->device;
87 list_del_init(&private->deferred_probe);
88
89 get_device(dev);
90
91 /*
92 * Drop the mutex while probing each device; the probe path may
93 * manipulate the deferred list
94 */
95 mutex_unlock(&deferred_probe_mutex);
96
97 /*
98 * Force the device to the end of the dpm_list since
99 * the PM code assumes that the order we add things to
100 * the list is a good order for suspend but deferred
101 * probe makes that very unsafe.
102 */
103 device_pm_lock();
104 device_pm_move_last(dev);
105 device_pm_unlock();
106
107 dev_dbg(dev, "Retrying from deferred list\n");
108 bus_probe_device(dev);
109
110 mutex_lock(&deferred_probe_mutex);
111
112 put_device(dev);
113 }
114 mutex_unlock(&deferred_probe_mutex);
115 }
116 static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
117
118 static void driver_deferred_probe_add(struct device *dev)
119 {
120 mutex_lock(&deferred_probe_mutex);
121 if (list_empty(&dev->p->deferred_probe)) {
122 dev_dbg(dev, "Added to deferred list\n");
123 list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
124 }
125 mutex_unlock(&deferred_probe_mutex);
126 }
127
128 void driver_deferred_probe_del(struct device *dev)
129 {
130 mutex_lock(&deferred_probe_mutex);
131 if (!list_empty(&dev->p->deferred_probe)) {
132 dev_dbg(dev, "Removed from deferred list\n");
133 list_del_init(&dev->p->deferred_probe);
134 }
135 mutex_unlock(&deferred_probe_mutex);
136 }
137
138 static bool driver_deferred_probe_enable = false;
139 /**
140 * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
141 *
142 * This functions moves all devices from the pending list to the active
143 * list and schedules the deferred probe workqueue to process them. It
144 * should be called anytime a driver is successfully bound to a device.
145 *
146 * Note, there is a race condition in multi-threaded probe. In the case where
147 * more than one device is probing at the same time, it is possible for one
148 * probe to complete successfully while another is about to defer. If the second
149 * depends on the first, then it will get put on the pending list after the
150 * trigger event has already occurred and will be stuck there.
151 *
152 * The atomic 'deferred_trigger_count' is used to determine if a successful
153 * trigger has occurred in the midst of probing a driver. If the trigger count
154 * changes in the midst of a probe, then deferred processing should be triggered
155 * again.
156 */
157 static void driver_deferred_probe_trigger(void)
158 {
159 if (!driver_deferred_probe_enable)
160 return;
161
162 /*
163 * A successful probe means that all the devices in the pending list
164 * should be triggered to be reprobed. Move all the deferred devices
165 * into the active list so they can be retried by the workqueue
166 */
167 mutex_lock(&deferred_probe_mutex);
168 atomic_inc(&deferred_trigger_count);
169 list_splice_tail_init(&deferred_probe_pending_list,
170 &deferred_probe_active_list);
171 mutex_unlock(&deferred_probe_mutex);
172
173 /*
174 * Kick the re-probe thread. It may already be scheduled, but it is
175 * safe to kick it again.
176 */
177 schedule_work(&deferred_probe_work);
178 }
179
180 /**
181 * device_block_probing() - Block/defere device's probes
182 *
183 * It will disable probing of devices and defer their probes instead.
184 */
185 void device_block_probing(void)
186 {
187 defer_all_probes = true;
188 /* sync with probes to avoid races. */
189 wait_for_device_probe();
190 }
191
192 /**
193 * device_unblock_probing() - Unblock/enable device's probes
194 *
195 * It will restore normal behavior and trigger re-probing of deferred
196 * devices.
197 */
198 void device_unblock_probing(void)
199 {
200 defer_all_probes = false;
201 driver_deferred_probe_trigger();
202 }
203
204 /**
205 * deferred_probe_initcall() - Enable probing of deferred devices
206 *
207 * We don't want to get in the way when the bulk of drivers are getting probed.
208 * Instead, this initcall makes sure that deferred probing is delayed until
209 * late_initcall time.
210 */
211 static int deferred_probe_initcall(void)
212 {
213 driver_deferred_probe_enable = true;
214 driver_deferred_probe_trigger();
215 /* Sort as many dependencies as possible before exiting initcalls */
216 flush_work(&deferred_probe_work);
217 return 0;
218 }
219 late_initcall(deferred_probe_initcall);
220
221 /**
222 * device_is_bound() - Check if device is bound to a driver
223 * @dev: device to check
224 *
225 * Returns true if passed device has already finished probing successfully
226 * against a driver.
227 *
228 * This function must be called with the device lock held.
229 */
230 bool device_is_bound(struct device *dev)
231 {
232 return dev->p && klist_node_attached(&dev->p->knode_driver);
233 }
234
235 static void driver_bound(struct device *dev)
236 {
237 if (device_is_bound(dev)) {
238 printk(KERN_WARNING "%s: device %s already bound\n",
239 __func__, kobject_name(&dev->kobj));
240 return;
241 }
242
243 pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->driver->name,
244 __func__, dev_name(dev));
245
246 klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
247
248 device_pm_check_callbacks(dev);
249
250 /*
251 * Make sure the device is no longer in one of the deferred lists and
252 * kick off retrying all pending devices
253 */
254 driver_deferred_probe_del(dev);
255 driver_deferred_probe_trigger();
256
257 if (dev->bus)
258 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
259 BUS_NOTIFY_BOUND_DRIVER, dev);
260 }
261
262 static int driver_sysfs_add(struct device *dev)
263 {
264 int ret;
265
266 if (dev->bus)
267 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
268 BUS_NOTIFY_BIND_DRIVER, dev);
269
270 ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
271 kobject_name(&dev->kobj));
272 if (ret == 0) {
273 ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
274 "driver");
275 if (ret)
276 sysfs_remove_link(&dev->driver->p->kobj,
277 kobject_name(&dev->kobj));
278 }
279 return ret;
280 }
281
282 static void driver_sysfs_remove(struct device *dev)
283 {
284 struct device_driver *drv = dev->driver;
285
286 if (drv) {
287 sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
288 sysfs_remove_link(&dev->kobj, "driver");
289 }
290 }
291
292 /**
293 * device_bind_driver - bind a driver to one device.
294 * @dev: device.
295 *
296 * Allow manual attachment of a driver to a device.
297 * Caller must have already set @dev->driver.
298 *
299 * Note that this does not modify the bus reference count
300 * nor take the bus's rwsem. Please verify those are accounted
301 * for before calling this. (It is ok to call with no other effort
302 * from a driver's probe() method.)
303 *
304 * This function must be called with the device lock held.
305 */
306 int device_bind_driver(struct device *dev)
307 {
308 int ret;
309
310 ret = driver_sysfs_add(dev);
311 if (!ret)
312 driver_bound(dev);
313 else if (dev->bus)
314 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
315 BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
316 return ret;
317 }
318 EXPORT_SYMBOL_GPL(device_bind_driver);
319
320 static atomic_t probe_count = ATOMIC_INIT(0);
321 static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
322
323 static int really_probe(struct device *dev, struct device_driver *drv)
324 {
325 int ret = -EPROBE_DEFER;
326 int local_trigger_count = atomic_read(&deferred_trigger_count);
327 bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE);
328
329 if (defer_all_probes) {
330 /*
331 * Value of defer_all_probes can be set only by
332 * device_defer_all_probes_enable() which, in turn, will call
333 * wait_for_device_probe() right after that to avoid any races.
334 */
335 dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
336 driver_deferred_probe_add(dev);
337 return ret;
338 }
339
340 atomic_inc(&probe_count);
341 pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
342 drv->bus->name, __func__, drv->name, dev_name(dev));
343 WARN_ON(!list_empty(&dev->devres_head));
344
345 re_probe:
346 dev->driver = drv;
347
348 /* If using pinctrl, bind pins now before probing */
349 ret = pinctrl_bind_pins(dev);
350 if (ret)
351 goto pinctrl_bind_failed;
352
353 if (driver_sysfs_add(dev)) {
354 printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
355 __func__, dev_name(dev));
356 goto probe_failed;
357 }
358
359 if (dev->pm_domain && dev->pm_domain->activate) {
360 ret = dev->pm_domain->activate(dev);
361 if (ret)
362 goto probe_failed;
363 }
364
365 /*
366 * Ensure devices are listed in devices_kset in correct order
367 * It's important to move Dev to the end of devices_kset before
368 * calling .probe, because it could be recursive and parent Dev
369 * should always go first
370 */
371 devices_kset_move_last(dev);
372
373 if (dev->bus->probe) {
374 ret = dev->bus->probe(dev);
375 if (ret)
376 goto probe_failed;
377 } else if (drv->probe) {
378 ret = drv->probe(dev);
379 if (ret)
380 goto probe_failed;
381 }
382
383 if (test_remove) {
384 test_remove = false;
385
386 if (dev->bus && dev->bus->remove)
387 dev->bus->remove(dev);
388 else if (drv->remove)
389 drv->remove(dev);
390
391 devres_release_all(dev);
392 driver_sysfs_remove(dev);
393 dev->driver = NULL;
394 dev_set_drvdata(dev, NULL);
395 if (dev->pm_domain && dev->pm_domain->dismiss)
396 dev->pm_domain->dismiss(dev);
397 pm_runtime_reinit(dev);
398
399 goto re_probe;
400 }
401
402 pinctrl_init_done(dev);
403
404 if (dev->pm_domain && dev->pm_domain->sync)
405 dev->pm_domain->sync(dev);
406
407 driver_bound(dev);
408 ret = 1;
409 pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
410 drv->bus->name, __func__, dev_name(dev), drv->name);
411 goto done;
412
413 probe_failed:
414 if (dev->bus)
415 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
416 BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
417 pinctrl_bind_failed:
418 devres_release_all(dev);
419 driver_sysfs_remove(dev);
420 dev->driver = NULL;
421 dev_set_drvdata(dev, NULL);
422 if (dev->pm_domain && dev->pm_domain->dismiss)
423 dev->pm_domain->dismiss(dev);
424 pm_runtime_reinit(dev);
425
426 switch (ret) {
427 case -EPROBE_DEFER:
428 /* Driver requested deferred probing */
429 dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
430 driver_deferred_probe_add(dev);
431 /* Did a trigger occur while probing? Need to re-trigger if yes */
432 if (local_trigger_count != atomic_read(&deferred_trigger_count))
433 driver_deferred_probe_trigger();
434 break;
435 case -ENODEV:
436 case -ENXIO:
437 pr_debug("%s: probe of %s rejects match %d\n",
438 drv->name, dev_name(dev), ret);
439 break;
440 default:
441 /* driver matched but the probe failed */
442 printk(KERN_WARNING
443 "%s: probe of %s failed with error %d\n",
444 drv->name, dev_name(dev), ret);
445 }
446 /*
447 * Ignore errors returned by ->probe so that the next driver can try
448 * its luck.
449 */
450 ret = 0;
451 done:
452 atomic_dec(&probe_count);
453 wake_up(&probe_waitqueue);
454 return ret;
455 }
456
457 /**
458 * driver_probe_done
459 * Determine if the probe sequence is finished or not.
460 *
461 * Should somehow figure out how to use a semaphore, not an atomic variable...
462 */
463 int driver_probe_done(void)
464 {
465 pr_debug("%s: probe_count = %d\n", __func__,
466 atomic_read(&probe_count));
467 if (atomic_read(&probe_count))
468 return -EBUSY;
469 return 0;
470 }
471
472 /**
473 * wait_for_device_probe
474 * Wait for device probing to be completed.
475 */
476 void wait_for_device_probe(void)
477 {
478 /* wait for the deferred probe workqueue to finish */
479 flush_work(&deferred_probe_work);
480
481 /* wait for the known devices to complete their probing */
482 wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
483 async_synchronize_full();
484 }
485 EXPORT_SYMBOL_GPL(wait_for_device_probe);
486
487 /**
488 * driver_probe_device - attempt to bind device & driver together
489 * @drv: driver to bind a device to
490 * @dev: device to try to bind to the driver
491 *
492 * This function returns -ENODEV if the device is not registered,
493 * 1 if the device is bound successfully and 0 otherwise.
494 *
495 * This function must be called with @dev lock held. When called for a
496 * USB interface, @dev->parent lock must be held as well.
497 *
498 * If the device has a parent, runtime-resume the parent before driver probing.
499 */
500 int driver_probe_device(struct device_driver *drv, struct device *dev)
501 {
502 int ret = 0;
503
504 if (!device_is_registered(dev))
505 return -ENODEV;
506
507 pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
508 drv->bus->name, __func__, dev_name(dev), drv->name);
509
510 if (dev->parent)
511 pm_runtime_get_sync(dev->parent);
512
513 pm_runtime_barrier(dev);
514 ret = really_probe(dev, drv);
515 pm_request_idle(dev);
516
517 if (dev->parent)
518 pm_runtime_put(dev->parent);
519
520 return ret;
521 }
522
523 bool driver_allows_async_probing(struct device_driver *drv)
524 {
525 switch (drv->probe_type) {
526 case PROBE_PREFER_ASYNCHRONOUS:
527 return true;
528
529 case PROBE_FORCE_SYNCHRONOUS:
530 return false;
531
532 default:
533 if (module_requested_async_probing(drv->owner))
534 return true;
535
536 return false;
537 }
538 }
539
540 struct device_attach_data {
541 struct device *dev;
542
543 /*
544 * Indicates whether we are are considering asynchronous probing or
545 * not. Only initial binding after device or driver registration
546 * (including deferral processing) may be done asynchronously, the
547 * rest is always synchronous, as we expect it is being done by
548 * request from userspace.
549 */
550 bool check_async;
551
552 /*
553 * Indicates if we are binding synchronous or asynchronous drivers.
554 * When asynchronous probing is enabled we'll execute 2 passes
555 * over drivers: first pass doing synchronous probing and second
556 * doing asynchronous probing (if synchronous did not succeed -
557 * most likely because there was no driver requiring synchronous
558 * probing - and we found asynchronous driver during first pass).
559 * The 2 passes are done because we can't shoot asynchronous
560 * probe for given device and driver from bus_for_each_drv() since
561 * driver pointer is not guaranteed to stay valid once
562 * bus_for_each_drv() iterates to the next driver on the bus.
563 */
564 bool want_async;
565
566 /*
567 * We'll set have_async to 'true' if, while scanning for matching
568 * driver, we'll encounter one that requests asynchronous probing.
569 */
570 bool have_async;
571 };
572
573 static int __device_attach_driver(struct device_driver *drv, void *_data)
574 {
575 struct device_attach_data *data = _data;
576 struct device *dev = data->dev;
577 bool async_allowed;
578 int ret;
579
580 /*
581 * Check if device has already been claimed. This may
582 * happen with driver loading, device discovery/registration,
583 * and deferred probe processing happens all at once with
584 * multiple threads.
585 */
586 if (dev->driver)
587 return -EBUSY;
588
589 ret = driver_match_device(drv, dev);
590 if (ret == 0) {
591 /* no match */
592 return 0;
593 } else if (ret == -EPROBE_DEFER) {
594 dev_dbg(dev, "Device match requests probe deferral\n");
595 driver_deferred_probe_add(dev);
596 } else if (ret < 0) {
597 dev_dbg(dev, "Bus failed to match device: %d", ret);
598 return ret;
599 } /* ret > 0 means positive match */
600
601 async_allowed = driver_allows_async_probing(drv);
602
603 if (async_allowed)
604 data->have_async = true;
605
606 if (data->check_async && async_allowed != data->want_async)
607 return 0;
608
609 return driver_probe_device(drv, dev);
610 }
611
612 static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
613 {
614 struct device *dev = _dev;
615 struct device_attach_data data = {
616 .dev = dev,
617 .check_async = true,
618 .want_async = true,
619 };
620
621 device_lock(dev);
622
623 if (dev->parent)
624 pm_runtime_get_sync(dev->parent);
625
626 bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver);
627 dev_dbg(dev, "async probe completed\n");
628
629 pm_request_idle(dev);
630
631 if (dev->parent)
632 pm_runtime_put(dev->parent);
633
634 device_unlock(dev);
635
636 put_device(dev);
637 }
638
639 static int __device_attach(struct device *dev, bool allow_async)
640 {
641 int ret = 0;
642
643 device_lock(dev);
644 if (dev->driver) {
645 if (device_is_bound(dev)) {
646 ret = 1;
647 goto out_unlock;
648 }
649 ret = device_bind_driver(dev);
650 if (ret == 0)
651 ret = 1;
652 else {
653 dev->driver = NULL;
654 ret = 0;
655 }
656 } else {
657 struct device_attach_data data = {
658 .dev = dev,
659 .check_async = allow_async,
660 .want_async = false,
661 };
662
663 if (dev->parent)
664 pm_runtime_get_sync(dev->parent);
665
666 ret = bus_for_each_drv(dev->bus, NULL, &data,
667 __device_attach_driver);
668 if (!ret && allow_async && data.have_async) {
669 /*
670 * If we could not find appropriate driver
671 * synchronously and we are allowed to do
672 * async probes and there are drivers that
673 * want to probe asynchronously, we'll
674 * try them.
675 */
676 dev_dbg(dev, "scheduling asynchronous probe\n");
677 get_device(dev);
678 async_schedule(__device_attach_async_helper, dev);
679 } else {
680 pm_request_idle(dev);
681 }
682
683 if (dev->parent)
684 pm_runtime_put(dev->parent);
685 }
686 out_unlock:
687 device_unlock(dev);
688 return ret;
689 }
690
691 /**
692 * device_attach - try to attach device to a driver.
693 * @dev: device.
694 *
695 * Walk the list of drivers that the bus has and call
696 * driver_probe_device() for each pair. If a compatible
697 * pair is found, break out and return.
698 *
699 * Returns 1 if the device was bound to a driver;
700 * 0 if no matching driver was found;
701 * -ENODEV if the device is not registered.
702 *
703 * When called for a USB interface, @dev->parent lock must be held.
704 */
705 int device_attach(struct device *dev)
706 {
707 return __device_attach(dev, false);
708 }
709 EXPORT_SYMBOL_GPL(device_attach);
710
711 void device_initial_probe(struct device *dev)
712 {
713 __device_attach(dev, true);
714 }
715
716 static int __driver_attach(struct device *dev, void *data)
717 {
718 struct device_driver *drv = data;
719 int ret;
720
721 /*
722 * Lock device and try to bind to it. We drop the error
723 * here and always return 0, because we need to keep trying
724 * to bind to devices and some drivers will return an error
725 * simply if it didn't support the device.
726 *
727 * driver_probe_device() will spit a warning if there
728 * is an error.
729 */
730
731 ret = driver_match_device(drv, dev);
732 if (ret == 0) {
733 /* no match */
734 return 0;
735 } else if (ret == -EPROBE_DEFER) {
736 dev_dbg(dev, "Device match requests probe deferral\n");
737 driver_deferred_probe_add(dev);
738 } else if (ret < 0) {
739 dev_dbg(dev, "Bus failed to match device: %d", ret);
740 return ret;
741 } /* ret > 0 means positive match */
742
743 if (dev->parent) /* Needed for USB */
744 device_lock(dev->parent);
745 device_lock(dev);
746 if (!dev->driver)
747 driver_probe_device(drv, dev);
748 device_unlock(dev);
749 if (dev->parent)
750 device_unlock(dev->parent);
751
752 return 0;
753 }
754
755 /**
756 * driver_attach - try to bind driver to devices.
757 * @drv: driver.
758 *
759 * Walk the list of devices that the bus has on it and try to
760 * match the driver with each one. If driver_probe_device()
761 * returns 0 and the @dev->driver is set, we've found a
762 * compatible pair.
763 */
764 int driver_attach(struct device_driver *drv)
765 {
766 return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
767 }
768 EXPORT_SYMBOL_GPL(driver_attach);
769
770 /*
771 * __device_release_driver() must be called with @dev lock held.
772 * When called for a USB interface, @dev->parent lock must be held as well.
773 */
774 static void __device_release_driver(struct device *dev)
775 {
776 struct device_driver *drv;
777
778 drv = dev->driver;
779 if (drv) {
780 if (driver_allows_async_probing(drv))
781 async_synchronize_full();
782
783 pm_runtime_get_sync(dev);
784
785 driver_sysfs_remove(dev);
786
787 if (dev->bus)
788 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
789 BUS_NOTIFY_UNBIND_DRIVER,
790 dev);
791
792 pm_runtime_put_sync(dev);
793
794 if (dev->bus && dev->bus->remove)
795 dev->bus->remove(dev);
796 else if (drv->remove)
797 drv->remove(dev);
798 devres_release_all(dev);
799 dev->driver = NULL;
800 dev_set_drvdata(dev, NULL);
801 if (dev->pm_domain && dev->pm_domain->dismiss)
802 dev->pm_domain->dismiss(dev);
803 pm_runtime_reinit(dev);
804
805 klist_remove(&dev->p->knode_driver);
806 device_pm_check_callbacks(dev);
807 if (dev->bus)
808 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
809 BUS_NOTIFY_UNBOUND_DRIVER,
810 dev);
811 }
812 }
813
814 /**
815 * device_release_driver - manually detach device from driver.
816 * @dev: device.
817 *
818 * Manually detach device from driver.
819 * When called for a USB interface, @dev->parent lock must be held.
820 */
821 void device_release_driver(struct device *dev)
822 {
823 /*
824 * If anyone calls device_release_driver() recursively from
825 * within their ->remove callback for the same device, they
826 * will deadlock right here.
827 */
828 device_lock(dev);
829 __device_release_driver(dev);
830 device_unlock(dev);
831 }
832 EXPORT_SYMBOL_GPL(device_release_driver);
833
834 /**
835 * driver_detach - detach driver from all devices it controls.
836 * @drv: driver.
837 */
838 void driver_detach(struct device_driver *drv)
839 {
840 struct device_private *dev_prv;
841 struct device *dev;
842
843 for (;;) {
844 spin_lock(&drv->p->klist_devices.k_lock);
845 if (list_empty(&drv->p->klist_devices.k_list)) {
846 spin_unlock(&drv->p->klist_devices.k_lock);
847 break;
848 }
849 dev_prv = list_entry(drv->p->klist_devices.k_list.prev,
850 struct device_private,
851 knode_driver.n_node);
852 dev = dev_prv->device;
853 get_device(dev);
854 spin_unlock(&drv->p->klist_devices.k_lock);
855
856 if (dev->parent) /* Needed for USB */
857 device_lock(dev->parent);
858 device_lock(dev);
859 if (dev->driver == drv)
860 __device_release_driver(dev);
861 device_unlock(dev);
862 if (dev->parent)
863 device_unlock(dev->parent);
864 put_device(dev);
865 }
866 }