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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
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49
50
51static DEFINE_MUTEX(deferred_probe_mutex);
52static LIST_HEAD(deferred_probe_pending_list);
53static LIST_HEAD(deferred_probe_active_list);
54static struct workqueue_struct *deferred_wq;
55static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
56
57
58
59
60
61
62static bool defer_all_probes;
63
64
65
66
67static void deferred_probe_work_func(struct work_struct *work)
68{
69 struct device *dev;
70 struct device_private *private;
71
72
73
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77
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79
80
81
82
83 mutex_lock(&deferred_probe_mutex);
84 while (!list_empty(&deferred_probe_active_list)) {
85 private = list_first_entry(&deferred_probe_active_list,
86 typeof(*dev->p), deferred_probe);
87 dev = private->device;
88 list_del_init(&private->deferred_probe);
89
90 get_device(dev);
91
92
93
94
95
96 mutex_unlock(&deferred_probe_mutex);
97
98
99
100
101
102
103
104 device_pm_lock();
105 device_pm_move_last(dev);
106 device_pm_unlock();
107
108 dev_dbg(dev, "Retrying from deferred list\n");
109 bus_probe_device(dev);
110
111 mutex_lock(&deferred_probe_mutex);
112
113 put_device(dev);
114 }
115 mutex_unlock(&deferred_probe_mutex);
116}
117static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
118
119static void driver_deferred_probe_add(struct device *dev)
120{
121 mutex_lock(&deferred_probe_mutex);
122 if (list_empty(&dev->p->deferred_probe)) {
123 dev_dbg(dev, "Added to deferred list\n");
124 list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
125 }
126 mutex_unlock(&deferred_probe_mutex);
127}
128
129void driver_deferred_probe_del(struct device *dev)
130{
131 mutex_lock(&deferred_probe_mutex);
132 if (!list_empty(&dev->p->deferred_probe)) {
133 dev_dbg(dev, "Removed from deferred list\n");
134 list_del_init(&dev->p->deferred_probe);
135 }
136 mutex_unlock(&deferred_probe_mutex);
137}
138
139static bool driver_deferred_probe_enable = false;
140
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151
152
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155
156
157
158static void driver_deferred_probe_trigger(void)
159{
160 if (!driver_deferred_probe_enable)
161 return;
162
163
164
165
166
167
168 mutex_lock(&deferred_probe_mutex);
169 atomic_inc(&deferred_trigger_count);
170 list_splice_tail_init(&deferred_probe_pending_list,
171 &deferred_probe_active_list);
172 mutex_unlock(&deferred_probe_mutex);
173
174
175
176
177
178 queue_work(deferred_wq, &deferred_probe_work);
179}
180
181
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183
184
185
186void device_block_probing(void)
187{
188 defer_all_probes = true;
189
190 wait_for_device_probe();
191}
192
193
194
195
196
197
198
199void device_unblock_probing(void)
200{
201 defer_all_probes = false;
202 driver_deferred_probe_trigger();
203}
204
205
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209
210
211
212static int deferred_probe_initcall(void)
213{
214 deferred_wq = create_singlethread_workqueue("deferwq");
215 if (WARN_ON(!deferred_wq))
216 return -ENOMEM;
217
218 driver_deferred_probe_enable = true;
219 driver_deferred_probe_trigger();
220
221 flush_workqueue(deferred_wq);
222 return 0;
223}
224late_initcall(deferred_probe_initcall);
225
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232
233
234
235bool device_is_bound(struct device *dev)
236{
237 return dev->p && klist_node_attached(&dev->p->knode_driver);
238}
239
240static void driver_bound(struct device *dev)
241{
242 if (device_is_bound(dev)) {
243 printk(KERN_WARNING "%s: device %s already bound\n",
244 __func__, kobject_name(&dev->kobj));
245 return;
246 }
247
248 pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->driver->name,
249 __func__, dev_name(dev));
250
251 klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
252
253 device_pm_check_callbacks(dev);
254
255
256
257
258
259 driver_deferred_probe_del(dev);
260 driver_deferred_probe_trigger();
261
262 if (dev->bus)
263 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
264 BUS_NOTIFY_BOUND_DRIVER, dev);
265}
266
267static int driver_sysfs_add(struct device *dev)
268{
269 int ret;
270
271 if (dev->bus)
272 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
273 BUS_NOTIFY_BIND_DRIVER, dev);
274
275 ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
276 kobject_name(&dev->kobj));
277 if (ret == 0) {
278 ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
279 "driver");
280 if (ret)
281 sysfs_remove_link(&dev->driver->p->kobj,
282 kobject_name(&dev->kobj));
283 }
284 return ret;
285}
286
287static void driver_sysfs_remove(struct device *dev)
288{
289 struct device_driver *drv = dev->driver;
290
291 if (drv) {
292 sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
293 sysfs_remove_link(&dev->kobj, "driver");
294 }
295}
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310
311int device_bind_driver(struct device *dev)
312{
313 int ret;
314
315 ret = driver_sysfs_add(dev);
316 if (!ret)
317 driver_bound(dev);
318 else if (dev->bus)
319 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
320 BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
321 return ret;
322}
323EXPORT_SYMBOL_GPL(device_bind_driver);
324
325static atomic_t probe_count = ATOMIC_INIT(0);
326static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
327
328static int really_probe(struct device *dev, struct device_driver *drv)
329{
330 int ret = -EPROBE_DEFER;
331 int local_trigger_count = atomic_read(&deferred_trigger_count);
332
333 if (defer_all_probes) {
334
335
336
337
338
339 dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
340 driver_deferred_probe_add(dev);
341 return ret;
342 }
343
344 atomic_inc(&probe_count);
345 pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
346 drv->bus->name, __func__, drv->name, dev_name(dev));
347 WARN_ON(!list_empty(&dev->devres_head));
348
349 dev->driver = drv;
350
351
352 ret = pinctrl_bind_pins(dev);
353 if (ret)
354 goto pinctrl_bind_failed;
355
356 if (driver_sysfs_add(dev)) {
357 printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
358 __func__, dev_name(dev));
359 goto probe_failed;
360 }
361
362 if (dev->pm_domain && dev->pm_domain->activate) {
363 ret = dev->pm_domain->activate(dev);
364 if (ret)
365 goto probe_failed;
366 }
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374 devices_kset_move_last(dev);
375
376 if (dev->bus->probe) {
377 ret = dev->bus->probe(dev);
378 if (ret)
379 goto probe_failed;
380 } else if (drv->probe) {
381 ret = drv->probe(dev);
382 if (ret)
383 goto probe_failed;
384 }
385
386 pinctrl_init_done(dev);
387
388 if (dev->pm_domain && dev->pm_domain->sync)
389 dev->pm_domain->sync(dev);
390
391 driver_bound(dev);
392 ret = 1;
393 pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
394 drv->bus->name, __func__, dev_name(dev), drv->name);
395 goto done;
396
397probe_failed:
398 if (dev->bus)
399 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
400 BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
401pinctrl_bind_failed:
402 devres_release_all(dev);
403 driver_sysfs_remove(dev);
404 dev->driver = NULL;
405 dev_set_drvdata(dev, NULL);
406 if (dev->pm_domain && dev->pm_domain->dismiss)
407 dev->pm_domain->dismiss(dev);
408 pm_runtime_reinit(dev);
409
410 switch (ret) {
411 case -EPROBE_DEFER:
412
413 dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
414 driver_deferred_probe_add(dev);
415
416 if (local_trigger_count != atomic_read(&deferred_trigger_count))
417 driver_deferred_probe_trigger();
418 break;
419 case -ENODEV:
420 case -ENXIO:
421 pr_debug("%s: probe of %s rejects match %d\n",
422 drv->name, dev_name(dev), ret);
423 break;
424 default:
425
426 printk(KERN_WARNING
427 "%s: probe of %s failed with error %d\n",
428 drv->name, dev_name(dev), ret);
429 }
430
431
432
433
434 ret = 0;
435done:
436 atomic_dec(&probe_count);
437 wake_up(&probe_waitqueue);
438 return ret;
439}
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442
443
444
445
446
447int driver_probe_done(void)
448{
449 pr_debug("%s: probe_count = %d\n", __func__,
450 atomic_read(&probe_count));
451 if (atomic_read(&probe_count))
452 return -EBUSY;
453 return 0;
454}
455
456
457
458
459
460void wait_for_device_probe(void)
461{
462
463 if (driver_deferred_probe_enable)
464 flush_workqueue(deferred_wq);
465
466
467 wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
468 async_synchronize_full();
469}
470EXPORT_SYMBOL_GPL(wait_for_device_probe);
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483
484
485int driver_probe_device(struct device_driver *drv, struct device *dev)
486{
487 int ret = 0;
488
489 if (!device_is_registered(dev))
490 return -ENODEV;
491
492 pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
493 drv->bus->name, __func__, dev_name(dev), drv->name);
494
495 if (dev->parent)
496 pm_runtime_get_sync(dev->parent);
497
498 pm_runtime_barrier(dev);
499 ret = really_probe(dev, drv);
500 pm_request_idle(dev);
501
502 if (dev->parent)
503 pm_runtime_put(dev->parent);
504
505 return ret;
506}
507
508bool driver_allows_async_probing(struct device_driver *drv)
509{
510 switch (drv->probe_type) {
511 case PROBE_PREFER_ASYNCHRONOUS:
512 return true;
513
514 case PROBE_FORCE_SYNCHRONOUS:
515 return false;
516
517 default:
518 if (module_requested_async_probing(drv->owner))
519 return true;
520
521 return false;
522 }
523}
524
525struct device_attach_data {
526 struct device *dev;
527
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531
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534
535 bool check_async;
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548
549 bool want_async;
550
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554
555 bool have_async;
556};
557
558static int __device_attach_driver(struct device_driver *drv, void *_data)
559{
560 struct device_attach_data *data = _data;
561 struct device *dev = data->dev;
562 bool async_allowed;
563 int ret;
564
565
566
567
568
569
570
571 if (dev->driver)
572 return -EBUSY;
573
574 ret = driver_match_device(drv, dev);
575 if (ret == 0) {
576
577 return 0;
578 } else if (ret == -EPROBE_DEFER) {
579 dev_dbg(dev, "Device match requests probe deferral\n");
580 driver_deferred_probe_add(dev);
581 } else if (ret < 0) {
582 dev_dbg(dev, "Bus failed to match device: %d", ret);
583 return ret;
584 }
585
586 async_allowed = driver_allows_async_probing(drv);
587
588 if (async_allowed)
589 data->have_async = true;
590
591 if (data->check_async && async_allowed != data->want_async)
592 return 0;
593
594 return driver_probe_device(drv, dev);
595}
596
597static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
598{
599 struct device *dev = _dev;
600 struct device_attach_data data = {
601 .dev = dev,
602 .check_async = true,
603 .want_async = true,
604 };
605
606 device_lock(dev);
607
608 if (dev->parent)
609 pm_runtime_get_sync(dev->parent);
610
611 bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver);
612 dev_dbg(dev, "async probe completed\n");
613
614 pm_request_idle(dev);
615
616 if (dev->parent)
617 pm_runtime_put(dev->parent);
618
619 device_unlock(dev);
620
621 put_device(dev);
622}
623
624static int __device_attach(struct device *dev, bool allow_async)
625{
626 int ret = 0;
627
628 device_lock(dev);
629 if (dev->driver) {
630 if (device_is_bound(dev)) {
631 ret = 1;
632 goto out_unlock;
633 }
634 ret = device_bind_driver(dev);
635 if (ret == 0)
636 ret = 1;
637 else {
638 dev->driver = NULL;
639 ret = 0;
640 }
641 } else {
642 struct device_attach_data data = {
643 .dev = dev,
644 .check_async = allow_async,
645 .want_async = false,
646 };
647
648 if (dev->parent)
649 pm_runtime_get_sync(dev->parent);
650
651 ret = bus_for_each_drv(dev->bus, NULL, &data,
652 __device_attach_driver);
653 if (!ret && allow_async && data.have_async) {
654
655
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657
658
659
660
661 dev_dbg(dev, "scheduling asynchronous probe\n");
662 get_device(dev);
663 async_schedule(__device_attach_async_helper, dev);
664 } else {
665 pm_request_idle(dev);
666 }
667
668 if (dev->parent)
669 pm_runtime_put(dev->parent);
670 }
671out_unlock:
672 device_unlock(dev);
673 return ret;
674}
675
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688
689
690int device_attach(struct device *dev)
691{
692 return __device_attach(dev, false);
693}
694EXPORT_SYMBOL_GPL(device_attach);
695
696void device_initial_probe(struct device *dev)
697{
698 __device_attach(dev, true);
699}
700
701static int __driver_attach(struct device *dev, void *data)
702{
703 struct device_driver *drv = data;
704 int ret;
705
706
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708
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710
711
712
713
714
715
716 ret = driver_match_device(drv, dev);
717 if (ret == 0) {
718
719 return 0;
720 } else if (ret == -EPROBE_DEFER) {
721 dev_dbg(dev, "Device match requests probe deferral\n");
722 driver_deferred_probe_add(dev);
723 } else if (ret < 0) {
724 dev_dbg(dev, "Bus failed to match device: %d", ret);
725 return ret;
726 }
727
728 if (dev->parent)
729 device_lock(dev->parent);
730 device_lock(dev);
731 if (!dev->driver)
732 driver_probe_device(drv, dev);
733 device_unlock(dev);
734 if (dev->parent)
735 device_unlock(dev->parent);
736
737 return 0;
738}
739
740
741
742
743
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745
746
747
748
749int driver_attach(struct device_driver *drv)
750{
751 return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
752}
753EXPORT_SYMBOL_GPL(driver_attach);
754
755
756
757
758
759static void __device_release_driver(struct device *dev)
760{
761 struct device_driver *drv;
762
763 drv = dev->driver;
764 if (drv) {
765 if (driver_allows_async_probing(drv))
766 async_synchronize_full();
767
768 pm_runtime_get_sync(dev);
769
770 driver_sysfs_remove(dev);
771
772 if (dev->bus)
773 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
774 BUS_NOTIFY_UNBIND_DRIVER,
775 dev);
776
777 pm_runtime_put_sync(dev);
778
779 if (dev->bus && dev->bus->remove)
780 dev->bus->remove(dev);
781 else if (drv->remove)
782 drv->remove(dev);
783 devres_release_all(dev);
784 dev->driver = NULL;
785 dev_set_drvdata(dev, NULL);
786 if (dev->pm_domain && dev->pm_domain->dismiss)
787 dev->pm_domain->dismiss(dev);
788 pm_runtime_reinit(dev);
789
790 klist_remove(&dev->p->knode_driver);
791 device_pm_check_callbacks(dev);
792 if (dev->bus)
793 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
794 BUS_NOTIFY_UNBOUND_DRIVER,
795 dev);
796 }
797}
798
799
800
801
802
803
804
805
806void device_release_driver(struct device *dev)
807{
808
809
810
811
812
813 device_lock(dev);
814 __device_release_driver(dev);
815 device_unlock(dev);
816}
817EXPORT_SYMBOL_GPL(device_release_driver);
818
819
820
821
822
823void driver_detach(struct device_driver *drv)
824{
825 struct device_private *dev_prv;
826 struct device *dev;
827
828 for (;;) {
829 spin_lock(&drv->p->klist_devices.k_lock);
830 if (list_empty(&drv->p->klist_devices.k_list)) {
831 spin_unlock(&drv->p->klist_devices.k_lock);
832 break;
833 }
834 dev_prv = list_entry(drv->p->klist_devices.k_list.prev,
835 struct device_private,
836 knode_driver.n_node);
837 dev = dev_prv->device;
838 get_device(dev);
839 spin_unlock(&drv->p->klist_devices.k_lock);
840
841 if (dev->parent)
842 device_lock(dev->parent);
843 device_lock(dev);
844 if (dev->driver == drv)
845 __device_release_driver(dev);
846 device_unlock(dev);
847 if (dev->parent)
848 device_unlock(dev->parent);
849 put_device(dev);
850 }
851}
852