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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 struct workqueue_struct *deferred_wq; | |
55 | static atomic_t deferred_trigger_count = ATOMIC_INIT(0); | |
56 | ||
57 | /* | |
58 | * In some cases, like suspend to RAM or hibernation, It might be reasonable | |
59 | * to prohibit probing of devices as it could be unsafe. | |
60 | * Once defer_all_probes is true all drivers probes will be forcibly deferred. | |
61 | */ | |
62 | static bool defer_all_probes; | |
63 | ||
64 | /* | |
65 | * deferred_probe_work_func() - Retry probing devices in the active list. | |
66 | */ | |
67 | static void deferred_probe_work_func(struct work_struct *work) | |
68 | { | |
69 | struct device *dev; | |
70 | struct device_private *private; | |
71 | /* | |
72 | * This block processes every device in the deferred 'active' list. | |
73 | * Each device is removed from the active list and passed to | |
74 | * bus_probe_device() to re-attempt the probe. The loop continues | |
75 | * until every device in the active list is removed and retried. | |
76 | * | |
77 | * Note: Once the device is removed from the list and the mutex is | |
78 | * released, it is possible for the device get freed by another thread | |
79 | * and cause a illegal pointer dereference. This code uses | |
80 | * get/put_device() to ensure the device structure cannot disappear | |
81 | * from under our feet. | |
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 | * Drop the mutex while probing each device; the probe path may | |
94 | * manipulate the deferred list | |
95 | */ | |
96 | mutex_unlock(&deferred_probe_mutex); | |
97 | ||
98 | /* | |
99 | * Force the device to the end of the dpm_list since | |
100 | * the PM code assumes that the order we add things to | |
101 | * the list is a good order for suspend but deferred | |
102 | * probe makes that very unsafe. | |
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 | } | |
117 | static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func); | |
118 | ||
119 | static 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 | ||
129 | void 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 | ||
139 | static bool driver_deferred_probe_enable = false; | |
140 | /** | |
141 | * driver_deferred_probe_trigger() - Kick off re-probing deferred devices | |
142 | * | |
143 | * This functions moves all devices from the pending list to the active | |
144 | * list and schedules the deferred probe workqueue to process them. It | |
145 | * should be called anytime a driver is successfully bound to a device. | |
146 | * | |
147 | * Note, there is a race condition in multi-threaded probe. In the case where | |
148 | * more than one device is probing at the same time, it is possible for one | |
149 | * probe to complete successfully while another is about to defer. If the second | |
150 | * depends on the first, then it will get put on the pending list after the | |
151 | * trigger event has already occurred and will be stuck there. | |
152 | * | |
153 | * The atomic 'deferred_trigger_count' is used to determine if a successful | |
154 | * trigger has occurred in the midst of probing a driver. If the trigger count | |
155 | * changes in the midst of a probe, then deferred processing should be triggered | |
156 | * again. | |
157 | */ | |
158 | static void driver_deferred_probe_trigger(void) | |
159 | { | |
160 | if (!driver_deferred_probe_enable) | |
161 | return; | |
162 | ||
163 | /* | |
164 | * A successful probe means that all the devices in the pending list | |
165 | * should be triggered to be reprobed. Move all the deferred devices | |
166 | * into the active list so they can be retried by the workqueue | |
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 | * Kick the re-probe thread. It may already be scheduled, but it is | |
176 | * safe to kick it again. | |
177 | */ | |
178 | queue_work(deferred_wq, &deferred_probe_work); | |
179 | } | |
180 | ||
181 | /** | |
182 | * device_block_probing() - Block/defere device's probes | |
183 | * | |
184 | * It will disable probing of devices and defer their probes instead. | |
185 | */ | |
186 | void device_block_probing(void) | |
187 | { | |
188 | defer_all_probes = true; | |
189 | /* sync with probes to avoid races. */ | |
190 | wait_for_device_probe(); | |
191 | } | |
192 | ||
193 | /** | |
194 | * device_unblock_probing() - Unblock/enable device's probes | |
195 | * | |
196 | * It will restore normal behavior and trigger re-probing of deferred | |
197 | * devices. | |
198 | */ | |
199 | void device_unblock_probing(void) | |
200 | { | |
201 | defer_all_probes = false; | |
202 | driver_deferred_probe_trigger(); | |
203 | } | |
204 | ||
205 | /** | |
206 | * deferred_probe_initcall() - Enable probing of deferred devices | |
207 | * | |
208 | * We don't want to get in the way when the bulk of drivers are getting probed. | |
209 | * Instead, this initcall makes sure that deferred probing is delayed until | |
210 | * late_initcall time. | |
211 | */ | |
212 | static 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 | /* Sort as many dependencies as possible before exiting initcalls */ | |
221 | flush_workqueue(deferred_wq); | |
222 | return 0; | |
223 | } | |
224 | late_initcall(deferred_probe_initcall); | |
225 | ||
226 | /** | |
227 | * device_is_bound() - Check if device is bound to a driver | |
228 | * @dev: device to check | |
229 | * | |
230 | * Returns true if passed device has already finished probing successfully | |
231 | * against a driver. | |
232 | * | |
233 | * This function must be called with the device lock held. | |
234 | */ | |
235 | bool device_is_bound(struct device *dev) | |
236 | { | |
237 | return dev->p && klist_node_attached(&dev->p->knode_driver); | |
238 | } | |
239 | ||
240 | static 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 | * Make sure the device is no longer in one of the deferred lists and | |
257 | * kick off retrying all pending devices | |
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 | ||
267 | static 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 | ||
287 | static 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 | } | |
296 | ||
297 | /** | |
298 | * device_bind_driver - bind a driver to one device. | |
299 | * @dev: device. | |
300 | * | |
301 | * Allow manual attachment of a driver to a device. | |
302 | * Caller must have already set @dev->driver. | |
303 | * | |
304 | * Note that this does not modify the bus reference count | |
305 | * nor take the bus's rwsem. Please verify those are accounted | |
306 | * for before calling this. (It is ok to call with no other effort | |
307 | * from a driver's probe() method.) | |
308 | * | |
309 | * This function must be called with the device lock held. | |
310 | */ | |
311 | int 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 | } | |
323 | EXPORT_SYMBOL_GPL(device_bind_driver); | |
324 | ||
325 | static atomic_t probe_count = ATOMIC_INIT(0); | |
326 | static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue); | |
327 | ||
328 | static 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 | * Value of defer_all_probes can be set only by | |
336 | * device_defer_all_probes_enable() which, in turn, will call | |
337 | * wait_for_device_probe() right after that to avoid any races. | |
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 | /* If using pinctrl, bind pins now before probing */ | |
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 | } | |
367 | ||
368 | /* | |
369 | * Ensure devices are listed in devices_kset in correct order | |
370 | * It's important to move Dev to the end of devices_kset before | |
371 | * calling .probe, because it could be recursive and parent Dev | |
372 | * should always go first | |
373 | */ | |
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 | ||
397 | probe_failed: | |
398 | if (dev->bus) | |
399 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, | |
400 | BUS_NOTIFY_DRIVER_NOT_BOUND, dev); | |
401 | pinctrl_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 | /* Driver requested deferred probing */ | |
413 | dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name); | |
414 | driver_deferred_probe_add(dev); | |
415 | /* Did a trigger occur while probing? Need to re-trigger if yes */ | |
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 | /* driver matched but the probe failed */ | |
426 | printk(KERN_WARNING | |
427 | "%s: probe of %s failed with error %d\n", | |
428 | drv->name, dev_name(dev), ret); | |
429 | } | |
430 | /* | |
431 | * Ignore errors returned by ->probe so that the next driver can try | |
432 | * its luck. | |
433 | */ | |
434 | ret = 0; | |
435 | done: | |
436 | atomic_dec(&probe_count); | |
437 | wake_up(&probe_waitqueue); | |
438 | return ret; | |
439 | } | |
440 | ||
441 | /** | |
442 | * driver_probe_done | |
443 | * Determine if the probe sequence is finished or not. | |
444 | * | |
445 | * Should somehow figure out how to use a semaphore, not an atomic variable... | |
446 | */ | |
447 | int 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 | * wait_for_device_probe | |
458 | * Wait for device probing to be completed. | |
459 | */ | |
460 | void wait_for_device_probe(void) | |
461 | { | |
462 | /* wait for the deferred probe workqueue to finish */ | |
463 | if (driver_deferred_probe_enable) | |
464 | flush_workqueue(deferred_wq); | |
465 | ||
466 | /* wait for the known devices to complete their probing */ | |
467 | wait_event(probe_waitqueue, atomic_read(&probe_count) == 0); | |
468 | async_synchronize_full(); | |
469 | } | |
470 | EXPORT_SYMBOL_GPL(wait_for_device_probe); | |
471 | ||
472 | /** | |
473 | * driver_probe_device - attempt to bind device & driver together | |
474 | * @drv: driver to bind a device to | |
475 | * @dev: device to try to bind to the driver | |
476 | * | |
477 | * This function returns -ENODEV if the device is not registered, | |
478 | * 1 if the device is bound successfully and 0 otherwise. | |
479 | * | |
480 | * This function must be called with @dev lock held. When called for a | |
481 | * USB interface, @dev->parent lock must be held as well. | |
482 | * | |
483 | * If the device has a parent, runtime-resume the parent before driver probing. | |
484 | */ | |
485 | int 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 | ||
508 | bool 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 | ||
525 | struct device_attach_data { | |
526 | struct device *dev; | |
527 | ||
528 | /* | |
529 | * Indicates whether we are are considering asynchronous probing or | |
530 | * not. Only initial binding after device or driver registration | |
531 | * (including deferral processing) may be done asynchronously, the | |
532 | * rest is always synchronous, as we expect it is being done by | |
533 | * request from userspace. | |
534 | */ | |
535 | bool check_async; | |
536 | ||
537 | /* | |
538 | * Indicates if we are binding synchronous or asynchronous drivers. | |
539 | * When asynchronous probing is enabled we'll execute 2 passes | |
540 | * over drivers: first pass doing synchronous probing and second | |
541 | * doing asynchronous probing (if synchronous did not succeed - | |
542 | * most likely because there was no driver requiring synchronous | |
543 | * probing - and we found asynchronous driver during first pass). | |
544 | * The 2 passes are done because we can't shoot asynchronous | |
545 | * probe for given device and driver from bus_for_each_drv() since | |
546 | * driver pointer is not guaranteed to stay valid once | |
547 | * bus_for_each_drv() iterates to the next driver on the bus. | |
548 | */ | |
549 | bool want_async; | |
550 | ||
551 | /* | |
552 | * We'll set have_async to 'true' if, while scanning for matching | |
553 | * driver, we'll encounter one that requests asynchronous probing. | |
554 | */ | |
555 | bool have_async; | |
556 | }; | |
557 | ||
558 | static 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 | * Check if device has already been claimed. This may | |
567 | * happen with driver loading, device discovery/registration, | |
568 | * and deferred probe processing happens all at once with | |
569 | * multiple threads. | |
570 | */ | |
571 | if (dev->driver) | |
572 | return -EBUSY; | |
573 | ||
574 | ret = driver_match_device(drv, dev); | |
575 | if (ret == 0) { | |
576 | /* no match */ | |
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 | } /* ret > 0 means positive match */ | |
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 | ||
597 | static 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 | ||
624 | static 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 | * If we could not find appropriate driver | |
656 | * synchronously and we are allowed to do | |
657 | * async probes and there are drivers that | |
658 | * want to probe asynchronously, we'll | |
659 | * try them. | |
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 | } | |
671 | out_unlock: | |
672 | device_unlock(dev); | |
673 | return ret; | |
674 | } | |
675 | ||
676 | /** | |
677 | * device_attach - try to attach device to a driver. | |
678 | * @dev: device. | |
679 | * | |
680 | * Walk the list of drivers that the bus has and call | |
681 | * driver_probe_device() for each pair. If a compatible | |
682 | * pair is found, break out and return. | |
683 | * | |
684 | * Returns 1 if the device was bound to a driver; | |
685 | * 0 if no matching driver was found; | |
686 | * -ENODEV if the device is not registered. | |
687 | * | |
688 | * When called for a USB interface, @dev->parent lock must be held. | |
689 | */ | |
690 | int device_attach(struct device *dev) | |
691 | { | |
692 | return __device_attach(dev, false); | |
693 | } | |
694 | EXPORT_SYMBOL_GPL(device_attach); | |
695 | ||
696 | void device_initial_probe(struct device *dev) | |
697 | { | |
698 | __device_attach(dev, true); | |
699 | } | |
700 | ||
701 | static int __driver_attach(struct device *dev, void *data) | |
702 | { | |
703 | struct device_driver *drv = data; | |
704 | int ret; | |
705 | ||
706 | /* | |
707 | * Lock device and try to bind to it. We drop the error | |
708 | * here and always return 0, because we need to keep trying | |
709 | * to bind to devices and some drivers will return an error | |
710 | * simply if it didn't support the device. | |
711 | * | |
712 | * driver_probe_device() will spit a warning if there | |
713 | * is an error. | |
714 | */ | |
715 | ||
716 | ret = driver_match_device(drv, dev); | |
717 | if (ret == 0) { | |
718 | /* no match */ | |
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 | } /* ret > 0 means positive match */ | |
727 | ||
728 | if (dev->parent) /* Needed for USB */ | |
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 | * driver_attach - try to bind driver to devices. | |
742 | * @drv: driver. | |
743 | * | |
744 | * Walk the list of devices that the bus has on it and try to | |
745 | * match the driver with each one. If driver_probe_device() | |
746 | * returns 0 and the @dev->driver is set, we've found a | |
747 | * compatible pair. | |
748 | */ | |
749 | int driver_attach(struct device_driver *drv) | |
750 | { | |
751 | return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); | |
752 | } | |
753 | EXPORT_SYMBOL_GPL(driver_attach); | |
754 | ||
755 | /* | |
756 | * __device_release_driver() must be called with @dev lock held. | |
757 | * When called for a USB interface, @dev->parent lock must be held as well. | |
758 | */ | |
759 | static 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 | * device_release_driver - manually detach device from driver. | |
801 | * @dev: device. | |
802 | * | |
803 | * Manually detach device from driver. | |
804 | * When called for a USB interface, @dev->parent lock must be held. | |
805 | */ | |
806 | void device_release_driver(struct device *dev) | |
807 | { | |
808 | /* | |
809 | * If anyone calls device_release_driver() recursively from | |
810 | * within their ->remove callback for the same device, they | |
811 | * will deadlock right here. | |
812 | */ | |
813 | device_lock(dev); | |
814 | __device_release_driver(dev); | |
815 | device_unlock(dev); | |
816 | } | |
817 | EXPORT_SYMBOL_GPL(device_release_driver); | |
818 | ||
819 | /** | |
820 | * driver_detach - detach driver from all devices it controls. | |
821 | * @drv: driver. | |
822 | */ | |
823 | void 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) /* Needed for USB */ | |
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 | } |