Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * drivers/base/dd.c - The core device/driver interactions.
4 : *
5 : * This file contains the (sometimes tricky) code that controls the
6 : * interactions between devices and drivers, which primarily includes
7 : * driver binding and unbinding.
8 : *
9 : * All of this code used to exist in drivers/base/bus.c, but was
10 : * relocated to here in the name of compartmentalization (since it wasn't
11 : * strictly code just for the 'struct bus_type'.
12 : *
13 : * Copyright (c) 2002-5 Patrick Mochel
14 : * Copyright (c) 2002-3 Open Source Development Labs
15 : * Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de>
16 : * Copyright (c) 2007-2009 Novell Inc.
17 : */
18 :
19 : #include <linux/debugfs.h>
20 : #include <linux/device.h>
21 : #include <linux/delay.h>
22 : #include <linux/dma-map-ops.h>
23 : #include <linux/init.h>
24 : #include <linux/module.h>
25 : #include <linux/kthread.h>
26 : #include <linux/wait.h>
27 : #include <linux/async.h>
28 : #include <linux/pm_runtime.h>
29 : #include <linux/pinctrl/devinfo.h>
30 : #include <linux/slab.h>
31 :
32 : #include "base.h"
33 : #include "power/power.h"
34 :
35 : /*
36 : * Deferred Probe infrastructure.
37 : *
38 : * Sometimes driver probe order matters, but the kernel doesn't always have
39 : * dependency information which means some drivers will get probed before a
40 : * resource it depends on is available. For example, an SDHCI driver may
41 : * first need a GPIO line from an i2c GPIO controller before it can be
42 : * initialized. If a required resource is not available yet, a driver can
43 : * request probing to be deferred by returning -EPROBE_DEFER from its probe hook
44 : *
45 : * Deferred probe maintains two lists of devices, a pending list and an active
46 : * list. A driver returning -EPROBE_DEFER causes the device to be added to the
47 : * pending list. A successful driver probe will trigger moving all devices
48 : * from the pending to the active list so that the workqueue will eventually
49 : * retry them.
50 : *
51 : * The deferred_probe_mutex must be held any time the deferred_probe_*_list
52 : * of the (struct device*)->p->deferred_probe pointers are manipulated
53 : */
54 : static DEFINE_MUTEX(deferred_probe_mutex);
55 : static LIST_HEAD(deferred_probe_pending_list);
56 : static LIST_HEAD(deferred_probe_active_list);
57 : static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
58 : static struct dentry *deferred_devices;
59 : static bool initcalls_done;
60 :
61 : /* Save the async probe drivers' name from kernel cmdline */
62 : #define ASYNC_DRV_NAMES_MAX_LEN 256
63 : static char async_probe_drv_names[ASYNC_DRV_NAMES_MAX_LEN];
64 :
65 : /*
66 : * In some cases, like suspend to RAM or hibernation, It might be reasonable
67 : * to prohibit probing of devices as it could be unsafe.
68 : * Once defer_all_probes is true all drivers probes will be forcibly deferred.
69 : */
70 : static bool defer_all_probes;
71 :
72 : /*
73 : * deferred_probe_work_func() - Retry probing devices in the active list.
74 : */
75 2 : static void deferred_probe_work_func(struct work_struct *work)
76 : {
77 2 : struct device *dev;
78 2 : struct device_private *private;
79 : /*
80 : * This block processes every device in the deferred 'active' list.
81 : * Each device is removed from the active list and passed to
82 : * bus_probe_device() to re-attempt the probe. The loop continues
83 : * until every device in the active list is removed and retried.
84 : *
85 : * Note: Once the device is removed from the list and the mutex is
86 : * released, it is possible for the device get freed by another thread
87 : * and cause a illegal pointer dereference. This code uses
88 : * get/put_device() to ensure the device structure cannot disappear
89 : * from under our feet.
90 : */
91 2 : mutex_lock(&deferred_probe_mutex);
92 2 : while (!list_empty(&deferred_probe_active_list)) {
93 0 : private = list_first_entry(&deferred_probe_active_list,
94 : typeof(*dev->p), deferred_probe);
95 0 : dev = private->device;
96 0 : list_del_init(&private->deferred_probe);
97 :
98 0 : get_device(dev);
99 :
100 : /*
101 : * Drop the mutex while probing each device; the probe path may
102 : * manipulate the deferred list
103 : */
104 0 : mutex_unlock(&deferred_probe_mutex);
105 :
106 : /*
107 : * Force the device to the end of the dpm_list since
108 : * the PM code assumes that the order we add things to
109 : * the list is a good order for suspend but deferred
110 : * probe makes that very unsafe.
111 : */
112 0 : device_pm_move_to_tail(dev);
113 :
114 0 : dev_dbg(dev, "Retrying from deferred list\n");
115 0 : bus_probe_device(dev);
116 0 : mutex_lock(&deferred_probe_mutex);
117 :
118 0 : put_device(dev);
119 : }
120 2 : mutex_unlock(&deferred_probe_mutex);
121 2 : }
122 : static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
123 :
124 0 : void driver_deferred_probe_add(struct device *dev)
125 : {
126 0 : mutex_lock(&deferred_probe_mutex);
127 0 : if (list_empty(&dev->p->deferred_probe)) {
128 0 : dev_dbg(dev, "Added to deferred list\n");
129 0 : list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
130 : }
131 0 : mutex_unlock(&deferred_probe_mutex);
132 0 : }
133 :
134 5 : void driver_deferred_probe_del(struct device *dev)
135 : {
136 5 : mutex_lock(&deferred_probe_mutex);
137 5 : if (!list_empty(&dev->p->deferred_probe)) {
138 0 : dev_dbg(dev, "Removed from deferred list\n");
139 0 : list_del_init(&dev->p->deferred_probe);
140 0 : kfree(dev->p->deferred_probe_reason);
141 0 : dev->p->deferred_probe_reason = NULL;
142 : }
143 5 : mutex_unlock(&deferred_probe_mutex);
144 5 : }
145 :
146 : static bool driver_deferred_probe_enable = false;
147 : /**
148 : * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
149 : *
150 : * This functions moves all devices from the pending list to the active
151 : * list and schedules the deferred probe workqueue to process them. It
152 : * should be called anytime a driver is successfully bound to a device.
153 : *
154 : * Note, there is a race condition in multi-threaded probe. In the case where
155 : * more than one device is probing at the same time, it is possible for one
156 : * probe to complete successfully while another is about to defer. If the second
157 : * depends on the first, then it will get put on the pending list after the
158 : * trigger event has already occurred and will be stuck there.
159 : *
160 : * The atomic 'deferred_trigger_count' is used to determine if a successful
161 : * trigger has occurred in the midst of probing a driver. If the trigger count
162 : * changes in the midst of a probe, then deferred processing should be triggered
163 : * again.
164 : */
165 7 : static void driver_deferred_probe_trigger(void)
166 : {
167 7 : if (!driver_deferred_probe_enable)
168 : return;
169 :
170 : /*
171 : * A successful probe means that all the devices in the pending list
172 : * should be triggered to be reprobed. Move all the deferred devices
173 : * into the active list so they can be retried by the workqueue
174 : */
175 2 : mutex_lock(&deferred_probe_mutex);
176 2 : atomic_inc(&deferred_trigger_count);
177 2 : list_splice_tail_init(&deferred_probe_pending_list,
178 : &deferred_probe_active_list);
179 2 : mutex_unlock(&deferred_probe_mutex);
180 :
181 : /*
182 : * Kick the re-probe thread. It may already be scheduled, but it is
183 : * safe to kick it again.
184 : */
185 2 : schedule_work(&deferred_probe_work);
186 : }
187 :
188 : /**
189 : * device_block_probing() - Block/defer device's probes
190 : *
191 : * It will disable probing of devices and defer their probes instead.
192 : */
193 0 : void device_block_probing(void)
194 : {
195 0 : defer_all_probes = true;
196 : /* sync with probes to avoid races. */
197 0 : wait_for_device_probe();
198 0 : }
199 :
200 : /**
201 : * device_unblock_probing() - Unblock/enable device's probes
202 : *
203 : * It will restore normal behavior and trigger re-probing of deferred
204 : * devices.
205 : */
206 0 : void device_unblock_probing(void)
207 : {
208 0 : defer_all_probes = false;
209 0 : driver_deferred_probe_trigger();
210 0 : }
211 :
212 : /**
213 : * device_set_deferred_probe_reason() - Set defer probe reason message for device
214 : * @dev: the pointer to the struct device
215 : * @vaf: the pointer to va_format structure with message
216 : */
217 0 : void device_set_deferred_probe_reason(const struct device *dev, struct va_format *vaf)
218 : {
219 0 : const char *drv = dev_driver_string(dev);
220 :
221 0 : mutex_lock(&deferred_probe_mutex);
222 :
223 0 : kfree(dev->p->deferred_probe_reason);
224 0 : dev->p->deferred_probe_reason = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf);
225 :
226 0 : mutex_unlock(&deferred_probe_mutex);
227 0 : }
228 :
229 : /*
230 : * deferred_devs_show() - Show the devices in the deferred probe pending list.
231 : */
232 0 : static int deferred_devs_show(struct seq_file *s, void *data)
233 : {
234 0 : struct device_private *curr;
235 :
236 0 : mutex_lock(&deferred_probe_mutex);
237 :
238 0 : list_for_each_entry(curr, &deferred_probe_pending_list, deferred_probe)
239 0 : seq_printf(s, "%s\t%s", dev_name(curr->device),
240 0 : curr->device->p->deferred_probe_reason ?: "\n");
241 :
242 0 : mutex_unlock(&deferred_probe_mutex);
243 :
244 0 : return 0;
245 : }
246 0 : DEFINE_SHOW_ATTRIBUTE(deferred_devs);
247 :
248 : int driver_deferred_probe_timeout;
249 : EXPORT_SYMBOL_GPL(driver_deferred_probe_timeout);
250 : static DECLARE_WAIT_QUEUE_HEAD(probe_timeout_waitqueue);
251 :
252 0 : static int __init deferred_probe_timeout_setup(char *str)
253 : {
254 0 : int timeout;
255 :
256 0 : if (!kstrtoint(str, 10, &timeout))
257 0 : driver_deferred_probe_timeout = timeout;
258 0 : return 1;
259 : }
260 : __setup("deferred_probe_timeout=", deferred_probe_timeout_setup);
261 :
262 : /**
263 : * driver_deferred_probe_check_state() - Check deferred probe state
264 : * @dev: device to check
265 : *
266 : * Return:
267 : * -ENODEV if initcalls have completed and modules are disabled.
268 : * -ETIMEDOUT if the deferred probe timeout was set and has expired
269 : * and modules are enabled.
270 : * -EPROBE_DEFER in other cases.
271 : *
272 : * Drivers or subsystems can opt-in to calling this function instead of directly
273 : * returning -EPROBE_DEFER.
274 : */
275 0 : int driver_deferred_probe_check_state(struct device *dev)
276 : {
277 0 : if (!IS_ENABLED(CONFIG_MODULES) && initcalls_done) {
278 0 : dev_warn(dev, "ignoring dependency for device, assuming no driver\n");
279 0 : return -ENODEV;
280 : }
281 :
282 : if (!driver_deferred_probe_timeout && initcalls_done) {
283 : dev_warn(dev, "deferred probe timeout, ignoring dependency\n");
284 : return -ETIMEDOUT;
285 : }
286 :
287 : return -EPROBE_DEFER;
288 : }
289 :
290 0 : static void deferred_probe_timeout_work_func(struct work_struct *work)
291 : {
292 0 : struct device_private *private, *p;
293 :
294 0 : driver_deferred_probe_timeout = 0;
295 0 : driver_deferred_probe_trigger();
296 0 : flush_work(&deferred_probe_work);
297 :
298 0 : list_for_each_entry_safe(private, p, &deferred_probe_pending_list, deferred_probe)
299 0 : dev_info(private->device, "deferred probe pending\n");
300 0 : wake_up_all(&probe_timeout_waitqueue);
301 0 : }
302 : static DECLARE_DELAYED_WORK(deferred_probe_timeout_work, deferred_probe_timeout_work_func);
303 :
304 : /**
305 : * deferred_probe_initcall() - Enable probing of deferred devices
306 : *
307 : * We don't want to get in the way when the bulk of drivers are getting probed.
308 : * Instead, this initcall makes sure that deferred probing is delayed until
309 : * late_initcall time.
310 : */
311 1 : static int deferred_probe_initcall(void)
312 : {
313 1 : deferred_devices = debugfs_create_file("devices_deferred", 0444, NULL,
314 : NULL, &deferred_devs_fops);
315 :
316 1 : driver_deferred_probe_enable = true;
317 1 : driver_deferred_probe_trigger();
318 : /* Sort as many dependencies as possible before exiting initcalls */
319 1 : flush_work(&deferred_probe_work);
320 1 : initcalls_done = true;
321 :
322 : /*
323 : * Trigger deferred probe again, this time we won't defer anything
324 : * that is optional
325 : */
326 1 : driver_deferred_probe_trigger();
327 1 : flush_work(&deferred_probe_work);
328 :
329 1 : if (driver_deferred_probe_timeout > 0) {
330 0 : schedule_delayed_work(&deferred_probe_timeout_work,
331 0 : driver_deferred_probe_timeout * HZ);
332 : }
333 1 : return 0;
334 : }
335 : late_initcall(deferred_probe_initcall);
336 :
337 0 : static void __exit deferred_probe_exit(void)
338 : {
339 0 : debugfs_remove_recursive(deferred_devices);
340 0 : }
341 : __exitcall(deferred_probe_exit);
342 :
343 : /**
344 : * device_is_bound() - Check if device is bound to a driver
345 : * @dev: device to check
346 : *
347 : * Returns true if passed device has already finished probing successfully
348 : * against a driver.
349 : *
350 : * This function must be called with the device lock held.
351 : */
352 5 : bool device_is_bound(struct device *dev)
353 : {
354 5 : return dev->p && klist_node_attached(&dev->p->knode_driver);
355 : }
356 :
357 5 : static void driver_bound(struct device *dev)
358 : {
359 5 : if (device_is_bound(dev)) {
360 0 : pr_warn("%s: device %s already bound\n",
361 : __func__, kobject_name(&dev->kobj));
362 0 : return;
363 : }
364 :
365 5 : pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->driver->name,
366 : __func__, dev_name(dev));
367 :
368 5 : klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
369 5 : device_links_driver_bound(dev);
370 :
371 5 : device_pm_check_callbacks(dev);
372 :
373 : /*
374 : * Make sure the device is no longer in one of the deferred lists and
375 : * kick off retrying all pending devices
376 : */
377 5 : driver_deferred_probe_del(dev);
378 5 : driver_deferred_probe_trigger();
379 :
380 5 : if (dev->bus)
381 5 : blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
382 : BUS_NOTIFY_BOUND_DRIVER, dev);
383 :
384 5 : kobject_uevent(&dev->kobj, KOBJ_BIND);
385 : }
386 :
387 0 : static ssize_t coredump_store(struct device *dev, struct device_attribute *attr,
388 : const char *buf, size_t count)
389 : {
390 0 : device_lock(dev);
391 0 : dev->driver->coredump(dev);
392 0 : device_unlock(dev);
393 :
394 0 : return count;
395 : }
396 : static DEVICE_ATTR_WO(coredump);
397 :
398 6 : static int driver_sysfs_add(struct device *dev)
399 : {
400 6 : int ret;
401 :
402 6 : if (dev->bus)
403 6 : blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
404 : BUS_NOTIFY_BIND_DRIVER, dev);
405 :
406 12 : ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
407 6 : kobject_name(&dev->kobj));
408 6 : if (ret)
409 0 : goto fail;
410 :
411 6 : ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
412 : "driver");
413 6 : if (ret)
414 0 : goto rm_dev;
415 :
416 : if (!IS_ENABLED(CONFIG_DEV_COREDUMP) || !dev->driver->coredump ||
417 : !device_create_file(dev, &dev_attr_coredump))
418 : return 0;
419 :
420 : sysfs_remove_link(&dev->kobj, "driver");
421 :
422 0 : rm_dev:
423 0 : sysfs_remove_link(&dev->driver->p->kobj,
424 0 : kobject_name(&dev->kobj));
425 :
426 : fail:
427 : return ret;
428 : }
429 :
430 1 : static void driver_sysfs_remove(struct device *dev)
431 : {
432 1 : struct device_driver *drv = dev->driver;
433 :
434 1 : if (drv) {
435 1 : if (drv->coredump)
436 0 : device_remove_file(dev, &dev_attr_coredump);
437 1 : sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
438 1 : sysfs_remove_link(&dev->kobj, "driver");
439 : }
440 1 : }
441 :
442 : /**
443 : * device_bind_driver - bind a driver to one device.
444 : * @dev: device.
445 : *
446 : * Allow manual attachment of a driver to a device.
447 : * Caller must have already set @dev->driver.
448 : *
449 : * Note that this does not modify the bus reference count.
450 : * Please verify that is accounted for before calling this.
451 : * (It is ok to call with no other effort from a driver's probe() method.)
452 : *
453 : * This function must be called with the device lock held.
454 : */
455 0 : int device_bind_driver(struct device *dev)
456 : {
457 0 : int ret;
458 :
459 0 : ret = driver_sysfs_add(dev);
460 0 : if (!ret)
461 0 : driver_bound(dev);
462 0 : else if (dev->bus)
463 0 : blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
464 : BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
465 0 : return ret;
466 : }
467 : EXPORT_SYMBOL_GPL(device_bind_driver);
468 :
469 : static atomic_t probe_count = ATOMIC_INIT(0);
470 : static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
471 :
472 0 : static void driver_deferred_probe_add_trigger(struct device *dev,
473 : int local_trigger_count)
474 : {
475 0 : driver_deferred_probe_add(dev);
476 : /* Did a trigger occur while probing? Need to re-trigger if yes */
477 0 : if (local_trigger_count != atomic_read(&deferred_trigger_count))
478 0 : driver_deferred_probe_trigger();
479 0 : }
480 :
481 0 : static ssize_t state_synced_show(struct device *dev,
482 : struct device_attribute *attr, char *buf)
483 : {
484 0 : bool val;
485 :
486 0 : device_lock(dev);
487 0 : val = dev->state_synced;
488 0 : device_unlock(dev);
489 :
490 0 : return sysfs_emit(buf, "%u\n", val);
491 : }
492 : static DEVICE_ATTR_RO(state_synced);
493 :
494 6 : static int really_probe(struct device *dev, struct device_driver *drv)
495 : {
496 6 : int ret = -EPROBE_DEFER;
497 6 : int local_trigger_count = atomic_read(&deferred_trigger_count);
498 6 : bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
499 : !drv->suppress_bind_attrs;
500 :
501 6 : if (defer_all_probes) {
502 : /*
503 : * Value of defer_all_probes can be set only by
504 : * device_block_probing() which, in turn, will call
505 : * wait_for_device_probe() right after that to avoid any races.
506 : */
507 0 : dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
508 0 : driver_deferred_probe_add(dev);
509 0 : return ret;
510 : }
511 :
512 6 : ret = device_links_check_suppliers(dev);
513 6 : if (ret == -EPROBE_DEFER)
514 0 : driver_deferred_probe_add_trigger(dev, local_trigger_count);
515 6 : if (ret)
516 : return ret;
517 :
518 6 : atomic_inc(&probe_count);
519 6 : pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
520 : drv->bus->name, __func__, drv->name, dev_name(dev));
521 6 : if (!list_empty(&dev->devres_head)) {
522 0 : dev_crit(dev, "Resources present before probing\n");
523 0 : ret = -EBUSY;
524 0 : goto done;
525 : }
526 :
527 6 : re_probe:
528 6 : dev->driver = drv;
529 :
530 : /* If using pinctrl, bind pins now before probing */
531 6 : ret = pinctrl_bind_pins(dev);
532 6 : if (ret)
533 : goto pinctrl_bind_failed;
534 :
535 6 : if (dev->bus->dma_configure) {
536 4 : ret = dev->bus->dma_configure(dev);
537 4 : if (ret)
538 0 : goto probe_failed;
539 : }
540 :
541 6 : if (driver_sysfs_add(dev)) {
542 0 : pr_err("%s: driver_sysfs_add(%s) failed\n",
543 : __func__, dev_name(dev));
544 0 : goto probe_failed;
545 : }
546 :
547 6 : if (dev->pm_domain && dev->pm_domain->activate) {
548 0 : ret = dev->pm_domain->activate(dev);
549 0 : if (ret)
550 0 : goto probe_failed;
551 : }
552 :
553 6 : if (dev->bus->probe) {
554 6 : ret = dev->bus->probe(dev);
555 6 : if (ret)
556 1 : goto probe_failed;
557 0 : } else if (drv->probe) {
558 0 : ret = drv->probe(dev);
559 0 : if (ret)
560 0 : goto probe_failed;
561 : }
562 :
563 5 : if (device_add_groups(dev, drv->dev_groups)) {
564 0 : dev_err(dev, "device_add_groups() failed\n");
565 0 : goto dev_groups_failed;
566 : }
567 :
568 5 : if (dev_has_sync_state(dev) &&
569 0 : device_create_file(dev, &dev_attr_state_synced)) {
570 0 : dev_err(dev, "state_synced sysfs add failed\n");
571 0 : goto dev_sysfs_state_synced_failed;
572 : }
573 :
574 5 : if (test_remove) {
575 : test_remove = false;
576 :
577 : device_remove_file(dev, &dev_attr_state_synced);
578 : device_remove_groups(dev, drv->dev_groups);
579 :
580 : if (dev->bus->remove)
581 : dev->bus->remove(dev);
582 : else if (drv->remove)
583 : drv->remove(dev);
584 :
585 : devres_release_all(dev);
586 : driver_sysfs_remove(dev);
587 : dev->driver = NULL;
588 : dev_set_drvdata(dev, NULL);
589 : if (dev->pm_domain && dev->pm_domain->dismiss)
590 : dev->pm_domain->dismiss(dev);
591 : pm_runtime_reinit(dev);
592 :
593 : goto re_probe;
594 : }
595 :
596 5 : pinctrl_init_done(dev);
597 :
598 5 : if (dev->pm_domain && dev->pm_domain->sync)
599 0 : dev->pm_domain->sync(dev);
600 :
601 5 : driver_bound(dev);
602 5 : ret = 1;
603 5 : pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
604 : drv->bus->name, __func__, dev_name(dev), drv->name);
605 5 : goto done;
606 :
607 0 : dev_sysfs_state_synced_failed:
608 0 : device_remove_groups(dev, drv->dev_groups);
609 0 : dev_groups_failed:
610 0 : if (dev->bus->remove)
611 0 : dev->bus->remove(dev);
612 0 : else if (drv->remove)
613 0 : drv->remove(dev);
614 0 : probe_failed:
615 1 : kfree(dev->dma_range_map);
616 1 : dev->dma_range_map = NULL;
617 1 : if (dev->bus)
618 1 : blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
619 : BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
620 0 : pinctrl_bind_failed:
621 1 : device_links_no_driver(dev);
622 1 : devres_release_all(dev);
623 1 : arch_teardown_dma_ops(dev);
624 1 : driver_sysfs_remove(dev);
625 1 : dev->driver = NULL;
626 1 : dev_set_drvdata(dev, NULL);
627 1 : if (dev->pm_domain && dev->pm_domain->dismiss)
628 0 : dev->pm_domain->dismiss(dev);
629 1 : pm_runtime_reinit(dev);
630 1 : dev_pm_set_driver_flags(dev, 0);
631 :
632 1 : switch (ret) {
633 : case -EPROBE_DEFER:
634 : /* Driver requested deferred probing */
635 0 : dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
636 0 : driver_deferred_probe_add_trigger(dev, local_trigger_count);
637 0 : break;
638 : case -ENODEV:
639 : case -ENXIO:
640 : pr_debug("%s: probe of %s rejects match %d\n",
641 : drv->name, dev_name(dev), ret);
642 : break;
643 : default:
644 : /* driver matched but the probe failed */
645 0 : pr_warn("%s: probe of %s failed with error %d\n",
646 : drv->name, dev_name(dev), ret);
647 : }
648 : /*
649 : * Ignore errors returned by ->probe so that the next driver can try
650 : * its luck.
651 : */
652 : ret = 0;
653 6 : done:
654 6 : atomic_dec(&probe_count);
655 6 : wake_up_all(&probe_waitqueue);
656 6 : return ret;
657 : }
658 :
659 : /*
660 : * For initcall_debug, show the driver probe time.
661 : */
662 0 : static int really_probe_debug(struct device *dev, struct device_driver *drv)
663 : {
664 0 : ktime_t calltime, rettime;
665 0 : int ret;
666 :
667 0 : calltime = ktime_get();
668 0 : ret = really_probe(dev, drv);
669 0 : rettime = ktime_get();
670 0 : pr_debug("probe of %s returned %d after %lld usecs\n",
671 : dev_name(dev), ret, ktime_us_delta(rettime, calltime));
672 0 : return ret;
673 : }
674 :
675 : /**
676 : * driver_probe_done
677 : * Determine if the probe sequence is finished or not.
678 : *
679 : * Should somehow figure out how to use a semaphore, not an atomic variable...
680 : */
681 0 : int driver_probe_done(void)
682 : {
683 0 : int local_probe_count = atomic_read(&probe_count);
684 :
685 0 : pr_debug("%s: probe_count = %d\n", __func__, local_probe_count);
686 0 : if (local_probe_count)
687 0 : return -EBUSY;
688 : return 0;
689 : }
690 :
691 : /**
692 : * wait_for_device_probe
693 : * Wait for device probing to be completed.
694 : */
695 1 : void wait_for_device_probe(void)
696 : {
697 : /* wait for probe timeout */
698 1 : wait_event(probe_timeout_waitqueue, !driver_deferred_probe_timeout);
699 :
700 : /* wait for the deferred probe workqueue to finish */
701 1 : flush_work(&deferred_probe_work);
702 :
703 : /* wait for the known devices to complete their probing */
704 1 : wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
705 1 : async_synchronize_full();
706 1 : }
707 : EXPORT_SYMBOL_GPL(wait_for_device_probe);
708 :
709 : /**
710 : * driver_probe_device - attempt to bind device & driver together
711 : * @drv: driver to bind a device to
712 : * @dev: device to try to bind to the driver
713 : *
714 : * This function returns -ENODEV if the device is not registered,
715 : * 1 if the device is bound successfully and 0 otherwise.
716 : *
717 : * This function must be called with @dev lock held. When called for a
718 : * USB interface, @dev->parent lock must be held as well.
719 : *
720 : * If the device has a parent, runtime-resume the parent before driver probing.
721 : */
722 6 : static int driver_probe_device(struct device_driver *drv, struct device *dev)
723 : {
724 6 : int ret = 0;
725 :
726 6 : if (!device_is_registered(dev))
727 : return -ENODEV;
728 :
729 6 : pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
730 : drv->bus->name, __func__, dev_name(dev), drv->name);
731 :
732 6 : pm_runtime_get_suppliers(dev);
733 6 : if (dev->parent)
734 6 : pm_runtime_get_sync(dev->parent);
735 :
736 6 : pm_runtime_barrier(dev);
737 6 : if (initcall_debug)
738 0 : ret = really_probe_debug(dev, drv);
739 : else
740 6 : ret = really_probe(dev, drv);
741 6 : pm_request_idle(dev);
742 :
743 6 : if (dev->parent)
744 6 : pm_runtime_put(dev->parent);
745 :
746 6 : pm_runtime_put_suppliers(dev);
747 6 : return ret;
748 : }
749 :
750 5 : static inline bool cmdline_requested_async_probing(const char *drv_name)
751 : {
752 5 : return parse_option_str(async_probe_drv_names, drv_name);
753 : }
754 :
755 : /* The option format is "driver_async_probe=drv_name1,drv_name2,..." */
756 0 : static int __init save_async_options(char *buf)
757 : {
758 0 : if (strlen(buf) >= ASYNC_DRV_NAMES_MAX_LEN)
759 0 : pr_warn("Too long list of driver names for 'driver_async_probe'!\n");
760 :
761 0 : strlcpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN);
762 0 : return 0;
763 : }
764 : __setup("driver_async_probe=", save_async_options);
765 :
766 7 : bool driver_allows_async_probing(struct device_driver *drv)
767 : {
768 7 : switch (drv->probe_type) {
769 : case PROBE_PREFER_ASYNCHRONOUS:
770 : return true;
771 :
772 2 : case PROBE_FORCE_SYNCHRONOUS:
773 2 : return false;
774 :
775 5 : default:
776 5 : if (cmdline_requested_async_probing(drv->name))
777 0 : return true;
778 :
779 7 : if (module_requested_async_probing(drv->owner))
780 : return true;
781 :
782 : return false;
783 : }
784 : }
785 :
786 : struct device_attach_data {
787 : struct device *dev;
788 :
789 : /*
790 : * Indicates whether we are are considering asynchronous probing or
791 : * not. Only initial binding after device or driver registration
792 : * (including deferral processing) may be done asynchronously, the
793 : * rest is always synchronous, as we expect it is being done by
794 : * request from userspace.
795 : */
796 : bool check_async;
797 :
798 : /*
799 : * Indicates if we are binding synchronous or asynchronous drivers.
800 : * When asynchronous probing is enabled we'll execute 2 passes
801 : * over drivers: first pass doing synchronous probing and second
802 : * doing asynchronous probing (if synchronous did not succeed -
803 : * most likely because there was no driver requiring synchronous
804 : * probing - and we found asynchronous driver during first pass).
805 : * The 2 passes are done because we can't shoot asynchronous
806 : * probe for given device and driver from bus_for_each_drv() since
807 : * driver pointer is not guaranteed to stay valid once
808 : * bus_for_each_drv() iterates to the next driver on the bus.
809 : */
810 : bool want_async;
811 :
812 : /*
813 : * We'll set have_async to 'true' if, while scanning for matching
814 : * driver, we'll encounter one that requests asynchronous probing.
815 : */
816 : bool have_async;
817 : };
818 :
819 2 : static int __device_attach_driver(struct device_driver *drv, void *_data)
820 : {
821 2 : struct device_attach_data *data = _data;
822 2 : struct device *dev = data->dev;
823 2 : bool async_allowed;
824 2 : int ret;
825 :
826 2 : ret = driver_match_device(drv, dev);
827 2 : if (ret == 0) {
828 : /* no match */
829 : return 0;
830 0 : } else if (ret == -EPROBE_DEFER) {
831 0 : dev_dbg(dev, "Device match requests probe deferral\n");
832 0 : driver_deferred_probe_add(dev);
833 0 : } else if (ret < 0) {
834 : dev_dbg(dev, "Bus failed to match device: %d\n", ret);
835 : return ret;
836 : } /* ret > 0 means positive match */
837 :
838 0 : async_allowed = driver_allows_async_probing(drv);
839 :
840 0 : if (async_allowed)
841 0 : data->have_async = true;
842 :
843 0 : if (data->check_async && async_allowed != data->want_async)
844 : return 0;
845 :
846 0 : return driver_probe_device(drv, dev);
847 : }
848 :
849 0 : static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
850 : {
851 0 : struct device *dev = _dev;
852 0 : struct device_attach_data data = {
853 : .dev = dev,
854 : .check_async = true,
855 : .want_async = true,
856 : };
857 :
858 0 : device_lock(dev);
859 :
860 : /*
861 : * Check if device has already been removed or claimed. This may
862 : * happen with driver loading, device discovery/registration,
863 : * and deferred probe processing happens all at once with
864 : * multiple threads.
865 : */
866 0 : if (dev->p->dead || dev->driver)
867 0 : goto out_unlock;
868 :
869 0 : if (dev->parent)
870 0 : pm_runtime_get_sync(dev->parent);
871 :
872 0 : bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver);
873 0 : dev_dbg(dev, "async probe completed\n");
874 :
875 0 : pm_request_idle(dev);
876 :
877 0 : if (dev->parent)
878 0 : pm_runtime_put(dev->parent);
879 0 : out_unlock:
880 0 : device_unlock(dev);
881 :
882 0 : put_device(dev);
883 0 : }
884 :
885 24 : static int __device_attach(struct device *dev, bool allow_async)
886 : {
887 24 : int ret = 0;
888 :
889 24 : device_lock(dev);
890 24 : if (dev->p->dead) {
891 0 : goto out_unlock;
892 24 : } else if (dev->driver) {
893 0 : if (device_is_bound(dev)) {
894 0 : ret = 1;
895 0 : goto out_unlock;
896 : }
897 0 : ret = device_bind_driver(dev);
898 0 : if (ret == 0)
899 : ret = 1;
900 : else {
901 0 : dev->driver = NULL;
902 0 : ret = 0;
903 : }
904 : } else {
905 24 : struct device_attach_data data = {
906 : .dev = dev,
907 : .check_async = allow_async,
908 : .want_async = false,
909 : };
910 :
911 24 : if (dev->parent)
912 24 : pm_runtime_get_sync(dev->parent);
913 :
914 24 : ret = bus_for_each_drv(dev->bus, NULL, &data,
915 : __device_attach_driver);
916 24 : if (!ret && allow_async && data.have_async) {
917 : /*
918 : * If we could not find appropriate driver
919 : * synchronously and we are allowed to do
920 : * async probes and there are drivers that
921 : * want to probe asynchronously, we'll
922 : * try them.
923 : */
924 0 : dev_dbg(dev, "scheduling asynchronous probe\n");
925 0 : get_device(dev);
926 0 : async_schedule_dev(__device_attach_async_helper, dev);
927 : } else {
928 24 : pm_request_idle(dev);
929 : }
930 :
931 24 : if (dev->parent)
932 24 : pm_runtime_put(dev->parent);
933 : }
934 24 : out_unlock:
935 24 : device_unlock(dev);
936 24 : return ret;
937 : }
938 :
939 : /**
940 : * device_attach - try to attach device to a driver.
941 : * @dev: device.
942 : *
943 : * Walk the list of drivers that the bus has and call
944 : * driver_probe_device() for each pair. If a compatible
945 : * pair is found, break out and return.
946 : *
947 : * Returns 1 if the device was bound to a driver;
948 : * 0 if no matching driver was found;
949 : * -ENODEV if the device is not registered.
950 : *
951 : * When called for a USB interface, @dev->parent lock must be held.
952 : */
953 0 : int device_attach(struct device *dev)
954 : {
955 0 : return __device_attach(dev, false);
956 : }
957 : EXPORT_SYMBOL_GPL(device_attach);
958 :
959 24 : void device_initial_probe(struct device *dev)
960 : {
961 24 : __device_attach(dev, true);
962 24 : }
963 :
964 : /*
965 : * __device_driver_lock - acquire locks needed to manipulate dev->drv
966 : * @dev: Device we will update driver info for
967 : * @parent: Parent device. Needed if the bus requires parent lock
968 : *
969 : * This function will take the required locks for manipulating dev->drv.
970 : * Normally this will just be the @dev lock, but when called for a USB
971 : * interface, @parent lock will be held as well.
972 : */
973 6 : static void __device_driver_lock(struct device *dev, struct device *parent)
974 : {
975 6 : if (parent && dev->bus->need_parent_lock)
976 0 : device_lock(parent);
977 6 : device_lock(dev);
978 6 : }
979 :
980 : /*
981 : * __device_driver_unlock - release locks needed to manipulate dev->drv
982 : * @dev: Device we will update driver info for
983 : * @parent: Parent device. Needed if the bus requires parent lock
984 : *
985 : * This function will release the required locks for manipulating dev->drv.
986 : * Normally this will just be the the @dev lock, but when called for a
987 : * USB interface, @parent lock will be released as well.
988 : */
989 6 : static void __device_driver_unlock(struct device *dev, struct device *parent)
990 : {
991 6 : device_unlock(dev);
992 6 : if (parent && dev->bus->need_parent_lock)
993 0 : device_unlock(parent);
994 6 : }
995 :
996 : /**
997 : * device_driver_attach - attach a specific driver to a specific device
998 : * @drv: Driver to attach
999 : * @dev: Device to attach it to
1000 : *
1001 : * Manually attach driver to a device. Will acquire both @dev lock and
1002 : * @dev->parent lock if needed.
1003 : */
1004 6 : int device_driver_attach(struct device_driver *drv, struct device *dev)
1005 : {
1006 6 : int ret = 0;
1007 :
1008 6 : __device_driver_lock(dev, dev->parent);
1009 :
1010 : /*
1011 : * If device has been removed or someone has already successfully
1012 : * bound a driver before us just skip the driver probe call.
1013 : */
1014 6 : if (!dev->p->dead && !dev->driver)
1015 6 : ret = driver_probe_device(drv, dev);
1016 :
1017 6 : __device_driver_unlock(dev, dev->parent);
1018 :
1019 6 : return ret;
1020 : }
1021 :
1022 0 : static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie)
1023 : {
1024 0 : struct device *dev = _dev;
1025 0 : struct device_driver *drv;
1026 0 : int ret = 0;
1027 :
1028 0 : __device_driver_lock(dev, dev->parent);
1029 :
1030 0 : drv = dev->p->async_driver;
1031 :
1032 : /*
1033 : * If device has been removed or someone has already successfully
1034 : * bound a driver before us just skip the driver probe call.
1035 : */
1036 0 : if (!dev->p->dead && !dev->driver)
1037 0 : ret = driver_probe_device(drv, dev);
1038 :
1039 0 : __device_driver_unlock(dev, dev->parent);
1040 :
1041 0 : dev_dbg(dev, "driver %s async attach completed: %d\n", drv->name, ret);
1042 :
1043 0 : put_device(dev);
1044 0 : }
1045 :
1046 36 : static int __driver_attach(struct device *dev, void *data)
1047 : {
1048 36 : struct device_driver *drv = data;
1049 36 : int ret;
1050 :
1051 : /*
1052 : * Lock device and try to bind to it. We drop the error
1053 : * here and always return 0, because we need to keep trying
1054 : * to bind to devices and some drivers will return an error
1055 : * simply if it didn't support the device.
1056 : *
1057 : * driver_probe_device() will spit a warning if there
1058 : * is an error.
1059 : */
1060 :
1061 36 : ret = driver_match_device(drv, dev);
1062 36 : if (ret == 0) {
1063 : /* no match */
1064 : return 0;
1065 6 : } else if (ret == -EPROBE_DEFER) {
1066 0 : dev_dbg(dev, "Device match requests probe deferral\n");
1067 0 : driver_deferred_probe_add(dev);
1068 6 : } else if (ret < 0) {
1069 : dev_dbg(dev, "Bus failed to match device: %d\n", ret);
1070 : return ret;
1071 : } /* ret > 0 means positive match */
1072 :
1073 6 : if (driver_allows_async_probing(drv)) {
1074 : /*
1075 : * Instead of probing the device synchronously we will
1076 : * probe it asynchronously to allow for more parallelism.
1077 : *
1078 : * We only take the device lock here in order to guarantee
1079 : * that the dev->driver and async_driver fields are protected
1080 : */
1081 0 : dev_dbg(dev, "probing driver %s asynchronously\n", drv->name);
1082 0 : device_lock(dev);
1083 0 : if (!dev->driver) {
1084 0 : get_device(dev);
1085 0 : dev->p->async_driver = drv;
1086 0 : async_schedule_dev(__driver_attach_async_helper, dev);
1087 : }
1088 0 : device_unlock(dev);
1089 0 : return 0;
1090 : }
1091 :
1092 6 : device_driver_attach(drv, dev);
1093 :
1094 6 : return 0;
1095 : }
1096 :
1097 : /**
1098 : * driver_attach - try to bind driver to devices.
1099 : * @drv: driver.
1100 : *
1101 : * Walk the list of devices that the bus has on it and try to
1102 : * match the driver with each one. If driver_probe_device()
1103 : * returns 0 and the @dev->driver is set, we've found a
1104 : * compatible pair.
1105 : */
1106 15 : int driver_attach(struct device_driver *drv)
1107 : {
1108 15 : return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
1109 : }
1110 : EXPORT_SYMBOL_GPL(driver_attach);
1111 :
1112 : /*
1113 : * __device_release_driver() must be called with @dev lock held.
1114 : * When called for a USB interface, @dev->parent lock must be held as well.
1115 : */
1116 0 : static void __device_release_driver(struct device *dev, struct device *parent)
1117 : {
1118 0 : struct device_driver *drv;
1119 :
1120 0 : drv = dev->driver;
1121 0 : if (drv) {
1122 0 : pm_runtime_get_sync(dev);
1123 :
1124 0 : while (device_links_busy(dev)) {
1125 0 : __device_driver_unlock(dev, parent);
1126 :
1127 0 : device_links_unbind_consumers(dev);
1128 :
1129 0 : __device_driver_lock(dev, parent);
1130 : /*
1131 : * A concurrent invocation of the same function might
1132 : * have released the driver successfully while this one
1133 : * was waiting, so check for that.
1134 : */
1135 0 : if (dev->driver != drv) {
1136 0 : pm_runtime_put(dev);
1137 : return;
1138 : }
1139 : }
1140 :
1141 0 : driver_sysfs_remove(dev);
1142 :
1143 0 : if (dev->bus)
1144 0 : blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1145 : BUS_NOTIFY_UNBIND_DRIVER,
1146 : dev);
1147 :
1148 0 : pm_runtime_put_sync(dev);
1149 :
1150 0 : device_remove_file(dev, &dev_attr_state_synced);
1151 0 : device_remove_groups(dev, drv->dev_groups);
1152 :
1153 0 : if (dev->bus && dev->bus->remove)
1154 0 : dev->bus->remove(dev);
1155 0 : else if (drv->remove)
1156 0 : drv->remove(dev);
1157 :
1158 0 : device_links_driver_cleanup(dev);
1159 :
1160 0 : devres_release_all(dev);
1161 0 : arch_teardown_dma_ops(dev);
1162 0 : dev->driver = NULL;
1163 0 : dev_set_drvdata(dev, NULL);
1164 0 : if (dev->pm_domain && dev->pm_domain->dismiss)
1165 0 : dev->pm_domain->dismiss(dev);
1166 0 : pm_runtime_reinit(dev);
1167 0 : dev_pm_set_driver_flags(dev, 0);
1168 :
1169 0 : klist_remove(&dev->p->knode_driver);
1170 0 : device_pm_check_callbacks(dev);
1171 0 : if (dev->bus)
1172 0 : blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1173 : BUS_NOTIFY_UNBOUND_DRIVER,
1174 : dev);
1175 :
1176 0 : kobject_uevent(&dev->kobj, KOBJ_UNBIND);
1177 : }
1178 : }
1179 :
1180 0 : void device_release_driver_internal(struct device *dev,
1181 : struct device_driver *drv,
1182 : struct device *parent)
1183 : {
1184 0 : __device_driver_lock(dev, parent);
1185 :
1186 0 : if (!drv || drv == dev->driver)
1187 0 : __device_release_driver(dev, parent);
1188 :
1189 0 : __device_driver_unlock(dev, parent);
1190 0 : }
1191 :
1192 : /**
1193 : * device_release_driver - manually detach device from driver.
1194 : * @dev: device.
1195 : *
1196 : * Manually detach device from driver.
1197 : * When called for a USB interface, @dev->parent lock must be held.
1198 : *
1199 : * If this function is to be called with @dev->parent lock held, ensure that
1200 : * the device's consumers are unbound in advance or that their locks can be
1201 : * acquired under the @dev->parent lock.
1202 : */
1203 0 : void device_release_driver(struct device *dev)
1204 : {
1205 : /*
1206 : * If anyone calls device_release_driver() recursively from
1207 : * within their ->remove callback for the same device, they
1208 : * will deadlock right here.
1209 : */
1210 0 : device_release_driver_internal(dev, NULL, NULL);
1211 0 : }
1212 : EXPORT_SYMBOL_GPL(device_release_driver);
1213 :
1214 : /**
1215 : * device_driver_detach - detach driver from a specific device
1216 : * @dev: device to detach driver from
1217 : *
1218 : * Detach driver from device. Will acquire both @dev lock and @dev->parent
1219 : * lock if needed.
1220 : */
1221 0 : void device_driver_detach(struct device *dev)
1222 : {
1223 0 : device_release_driver_internal(dev, NULL, dev->parent);
1224 0 : }
1225 :
1226 : /**
1227 : * driver_detach - detach driver from all devices it controls.
1228 : * @drv: driver.
1229 : */
1230 1 : void driver_detach(struct device_driver *drv)
1231 : {
1232 1 : struct device_private *dev_prv;
1233 1 : struct device *dev;
1234 :
1235 1 : if (driver_allows_async_probing(drv))
1236 0 : async_synchronize_full();
1237 :
1238 1 : for (;;) {
1239 1 : spin_lock(&drv->p->klist_devices.k_lock);
1240 1 : if (list_empty(&drv->p->klist_devices.k_list)) {
1241 1 : spin_unlock(&drv->p->klist_devices.k_lock);
1242 1 : break;
1243 : }
1244 0 : dev_prv = list_last_entry(&drv->p->klist_devices.k_list,
1245 : struct device_private,
1246 : knode_driver.n_node);
1247 0 : dev = dev_prv->device;
1248 0 : get_device(dev);
1249 0 : spin_unlock(&drv->p->klist_devices.k_lock);
1250 0 : device_release_driver_internal(dev, drv, dev->parent);
1251 0 : put_device(dev);
1252 : }
1253 1 : }
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