projects/linux·blob assoc-array-fixes · refs

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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 <[email protected]>
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_domain.h>
29#include <linux/pm_runtime.h>
30#include <linux/pinctrl/devinfo.h>
31#include <linux/slab.h>
32
33#include "base.h"
34#include "power/power.h"
35
36/*
37 * Deferred Probe infrastructure.
38 *
39 * Sometimes driver probe order matters, but the kernel doesn't always have
40 * dependency information which means some drivers will get probed before a
41 * resource it depends on is available. For example, an SDHCI driver may
42 * first need a GPIO line from an i2c GPIO controller before it can be
43 * initialized. If a required resource is not available yet, a driver can
44 * request probing to be deferred by returning -EPROBE_DEFER from its probe hook
45 *
46 * Deferred probe maintains two lists of devices, a pending list and an active
47 * list. A driver returning -EPROBE_DEFER causes the device to be added to the
48 * pending list. A successful driver probe will trigger moving all devices
49 * from the pending to the active list so that the workqueue will eventually
50 * retry them.
51 *
52 * The deferred_probe_mutex must be held any time the deferred_probe_*_list
53 * of the (struct device*)->p->deferred_probe pointers are manipulated
54 */
55static DEFINE_MUTEX(deferred_probe_mutex);
56static LIST_HEAD(deferred_probe_pending_list);
57static LIST_HEAD(deferred_probe_active_list);
58static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
59static bool initcalls_done;
60
61/* Save the async probe drivers' name from kernel cmdline */
62#define ASYNC_DRV_NAMES_MAX_LEN 256
63static char async_probe_drv_names[ASYNC_DRV_NAMES_MAX_LEN];
64static bool async_probe_default;
65
66/*
67 * In some cases, like suspend to RAM or hibernation, It might be reasonable
68 * to prohibit probing of devices as it could be unsafe.
69 * Once defer_all_probes is true all drivers probes will be forcibly deferred.
70 */
71static bool defer_all_probes;
72
73static void __device_set_deferred_probe_reason(const struct device *dev, char *reason)
74{
75 kfree(dev->p->deferred_probe_reason);
76 dev->p->deferred_probe_reason = reason;
77}
78
79/*
80 * deferred_probe_work_func() - Retry probing devices in the active list.
81 */
82static void deferred_probe_work_func(struct work_struct *work)
83{
84 struct device *dev;
85 struct device_private *private;
86 /*
87 * This block processes every device in the deferred 'active' list.
88 * Each device is removed from the active list and passed to
89 * bus_probe_device() to re-attempt the probe. The loop continues
90 * until every device in the active list is removed and retried.
91 *
92 * Note: Once the device is removed from the list and the mutex is
93 * released, it is possible for the device get freed by another thread
94 * and cause a illegal pointer dereference. This code uses
95 * get/put_device() to ensure the device structure cannot disappear
96 * from under our feet.
97 */
98 mutex_lock(&deferred_probe_mutex);
99 while (!list_empty(&deferred_probe_active_list)) {
100 private = list_first_entry(&deferred_probe_active_list,
101 typeof(*dev->p), deferred_probe);
102 dev = private->device;
103 list_del_init(&private->deferred_probe);
104
105 get_device(dev);
106
107 __device_set_deferred_probe_reason(dev, NULL);
108
109 /*
110 * Drop the mutex while probing each device; the probe path may
111 * manipulate the deferred list
112 */
113 mutex_unlock(&deferred_probe_mutex);
114
115 /*
116 * Force the device to the end of the dpm_list since
117 * the PM code assumes that the order we add things to
118 * the list is a good order for suspend but deferred
119 * probe makes that very unsafe.
120 */
121 device_pm_move_to_tail(dev);
122
123 dev_dbg(dev, "Retrying from deferred list\n");
124 bus_probe_device(dev);
125 mutex_lock(&deferred_probe_mutex);
126
127 put_device(dev);
128 }
129 mutex_unlock(&deferred_probe_mutex);
130}
131static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
132
133void driver_deferred_probe_add(struct device *dev)
134{
135 if (!dev_can_match(dev))
136 return;
137
138 mutex_lock(&deferred_probe_mutex);
139 if (list_empty(&dev->p->deferred_probe)) {
140 dev_dbg(dev, "Added to deferred list\n");
141 list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
142 }
143 mutex_unlock(&deferred_probe_mutex);
144}
145
146void driver_deferred_probe_del(struct device *dev)
147{
148 mutex_lock(&deferred_probe_mutex);
149 if (!list_empty(&dev->p->deferred_probe)) {
150 dev_dbg(dev, "Removed from deferred list\n");
151 list_del_init(&dev->p->deferred_probe);
152 __device_set_deferred_probe_reason(dev, NULL);
153 }
154 mutex_unlock(&deferred_probe_mutex);
155}
156
157static bool driver_deferred_probe_enable;
158/**
159 * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
160 *
161 * This functions moves all devices from the pending list to the active
162 * list and schedules the deferred probe workqueue to process them. It
163 * should be called anytime a driver is successfully bound to a device.
164 *
165 * Note, there is a race condition in multi-threaded probe. In the case where
166 * more than one device is probing at the same time, it is possible for one
167 * probe to complete successfully while another is about to defer. If the second
168 * depends on the first, then it will get put on the pending list after the
169 * trigger event has already occurred and will be stuck there.
170 *
171 * The atomic 'deferred_trigger_count' is used to determine if a successful
172 * trigger has occurred in the midst of probing a driver. If the trigger count
173 * changes in the midst of a probe, then deferred processing should be triggered
174 * again.
175 */
176void driver_deferred_probe_trigger(void)
177{
178 if (!driver_deferred_probe_enable)
179 return;
180
181 /*
182 * A successful probe means that all the devices in the pending list
183 * should be triggered to be reprobed. Move all the deferred devices
184 * into the active list so they can be retried by the workqueue
185 */
186 mutex_lock(&deferred_probe_mutex);
187 atomic_inc(&deferred_trigger_count);
188 list_splice_tail_init(&deferred_probe_pending_list,
189 &deferred_probe_active_list);
190 mutex_unlock(&deferred_probe_mutex);
191
192 /*
193 * Kick the re-probe thread. It may already be scheduled, but it is
194 * safe to kick it again.
195 */
196 queue_work(system_dfl_wq, &deferred_probe_work);
197}
198
199/**
200 * device_block_probing() - Block/defer device's probes
201 *
202 * It will disable probing of devices and defer their probes instead.
203 */
204void device_block_probing(void)
205{
206 defer_all_probes = true;
207 /* sync with probes to avoid races. */
208 wait_for_device_probe();
209}
210
211/**
212 * device_unblock_probing() - Unblock/enable device's probes
213 *
214 * It will restore normal behavior and trigger re-probing of deferred
215 * devices.
216 */
217void device_unblock_probing(void)
218{
219 defer_all_probes = false;
220 driver_deferred_probe_trigger();
221}
222
223/**
224 * device_set_deferred_probe_reason() - Set defer probe reason message for device
225 * @dev: the pointer to the struct device
226 * @vaf: the pointer to va_format structure with message
227 */
228void device_set_deferred_probe_reason(const struct device *dev, struct va_format *vaf)
229{
230 const char *drv = dev_driver_string(dev);
231 char *reason;
232
233 mutex_lock(&deferred_probe_mutex);
234
235 reason = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf);
236 __device_set_deferred_probe_reason(dev, reason);
237
238 mutex_unlock(&deferred_probe_mutex);
239}
240
241/*
242 * deferred_devs_show() - Show the devices in the deferred probe pending list.
243 */
244static int deferred_devs_show(struct seq_file *s, void *data)
245{
246 struct device_private *curr;
247
248 mutex_lock(&deferred_probe_mutex);
249
250 list_for_each_entry(curr, &deferred_probe_pending_list, deferred_probe)
251 seq_printf(s, "%s\t%s", dev_name(curr->device),
252 curr->deferred_probe_reason ?: "\n");
253
254 mutex_unlock(&deferred_probe_mutex);
255
256 return 0;
257}
258DEFINE_SHOW_ATTRIBUTE(deferred_devs);
259
260static int driver_deferred_probe_timeout = CONFIG_DRIVER_DEFERRED_PROBE_TIMEOUT;
261
262static int __init deferred_probe_timeout_setup(char *str)
263{
264 int timeout;
265
266 if (!kstrtoint(str, 10, &timeout))
267 driver_deferred_probe_timeout = timeout;
268 return 1;
269}
270__setup("deferred_probe_timeout=", deferred_probe_timeout_setup);
271
272/**
273 * driver_deferred_probe_check_state() - Check deferred probe state
274 * @dev: device to check
275 *
276 * Return:
277 * * -ENODEV if initcalls have completed and modules are disabled.
278 * * -ETIMEDOUT if the deferred probe timeout was set and has expired
279 * and modules are enabled.
280 * * -EPROBE_DEFER in other cases.
281 *
282 * Drivers or subsystems can opt-in to calling this function instead of directly
283 * returning -EPROBE_DEFER.
284 */
285int driver_deferred_probe_check_state(struct device *dev)
286{
287 if (!IS_ENABLED(CONFIG_MODULES) && initcalls_done) {
288 dev_warn(dev, "ignoring dependency for device, assuming no driver\n");
289 return -ENODEV;
290 }
291
292 if (!driver_deferred_probe_timeout && initcalls_done) {
293 dev_warn(dev, "deferred probe timeout, ignoring dependency\n");
294 return -ETIMEDOUT;
295 }
296
297 return -EPROBE_DEFER;
298}
299EXPORT_SYMBOL_GPL(driver_deferred_probe_check_state);
300
301static void deferred_probe_timeout_work_func(struct work_struct *work)
302{
303 struct device_private *p;
304
305 fw_devlink_drivers_done();
306
307 driver_deferred_probe_timeout = 0;
308 driver_deferred_probe_trigger();
309 flush_work(&deferred_probe_work);
310
311 mutex_lock(&deferred_probe_mutex);
312 list_for_each_entry(p, &deferred_probe_pending_list, deferred_probe)
313 dev_warn(p->device, "deferred probe pending: %s", p->deferred_probe_reason ?: "(reason unknown)\n");
314 mutex_unlock(&deferred_probe_mutex);
315
316 fw_devlink_probing_done();
317}
318static DECLARE_DELAYED_WORK(deferred_probe_timeout_work, deferred_probe_timeout_work_func);
319
320void deferred_probe_extend_timeout(void)
321{
322 /*
323 * If the work hasn't been queued yet or if the work expired, don't
324 * start a new one.
325 */
326 if (delayed_work_pending(&deferred_probe_timeout_work) &&
327 mod_delayed_work(system_percpu_wq, &deferred_probe_timeout_work,
328 secs_to_jiffies(driver_deferred_probe_timeout)))
329 pr_debug("Extended deferred probe timeout by %d secs\n",
330 driver_deferred_probe_timeout);
331}
332
333/**
334 * deferred_probe_initcall() - Enable probing of deferred devices
335 *
336 * We don't want to get in the way when the bulk of drivers are getting probed.
337 * Instead, this initcall makes sure that deferred probing is delayed until
338 * late_initcall time.
339 */
340static int deferred_probe_initcall(void)
341{
342 debugfs_create_file("devices_deferred", 0444, NULL, NULL,
343 &deferred_devs_fops);
344
345 driver_deferred_probe_enable = true;
346 driver_deferred_probe_trigger();
347 /* Sort as many dependencies as possible before exiting initcalls */
348 flush_work(&deferred_probe_work);
349 initcalls_done = true;
350
351 if (!IS_ENABLED(CONFIG_MODULES))
352 fw_devlink_drivers_done();
353
354 /*
355 * Trigger deferred probe again, this time we won't defer anything
356 * that is optional
357 */
358 driver_deferred_probe_trigger();
359 flush_work(&deferred_probe_work);
360
361 if (driver_deferred_probe_timeout > 0) {
362 schedule_delayed_work(&deferred_probe_timeout_work,
363 driver_deferred_probe_timeout * HZ);
364 }
365
366 if (!IS_ENABLED(CONFIG_MODULES))
367 fw_devlink_probing_done();
368
369 return 0;
370}
371late_initcall(deferred_probe_initcall);
372
373static void __exit deferred_probe_exit(void)
374{
375 debugfs_lookup_and_remove("devices_deferred", NULL);
376}
377__exitcall(deferred_probe_exit);
378
379int __device_set_driver_override(struct device *dev, const char *s, size_t len)
380{
381 const char *new = NULL, *old;
382
383 if (!s)
384 return -EINVAL;
385
386 /*
387 * The stored value will be used in sysfs show callback (sysfs_emit()),
388 * which has a length limit of PAGE_SIZE and adds a trailing newline.
389 * Thus we can store one character less to avoid truncation during sysfs
390 * show.
391 */
392 if (len >= (PAGE_SIZE - 1))
393 return -EINVAL;
394
395 /*
396 * Compute the real length of the string in case userspace sends us a
397 * bunch of \0 characters like python likes to do.
398 */
399 len = strlen(s);
400
401 /* Handle trailing newline */
402 if (len) {
403 char *cp;
404
405 cp = strnchr(s, len, '\n');
406 if (cp)
407 len = cp - s;
408 }
409
410 /*
411 * If empty string or "\n" passed, new remains NULL, clearing
412 * the driver_override.name.
413 */
414 if (len) {
415 new = kstrndup(s, len, GFP_KERNEL);
416 if (!new)
417 return -ENOMEM;
418 }
419
420 scoped_guard(spinlock, &dev->driver_override.lock) {
421 old = dev->driver_override.name;
422 dev->driver_override.name = new;
423 }
424
425 kfree(old);
426
427 return 0;
428}
429EXPORT_SYMBOL_GPL(__device_set_driver_override);
430
431/**
432 * device_is_bound() - Check if device is bound to a driver
433 * @dev: device to check
434 *
435 * Returns true if passed device has already finished probing successfully
436 * against a driver.
437 *
438 * This function must be called with the device lock held.
439 */
440bool device_is_bound(struct device *dev)
441{
442 return dev->p && klist_node_attached(&dev->p->knode_driver);
443}
444EXPORT_SYMBOL_GPL(device_is_bound);
445
446static void driver_bound(struct device *dev)
447{
448 if (device_is_bound(dev)) {
449 dev_warn(dev, "%s: device already bound\n", __func__);
450 return;
451 }
452
453 dev_dbg(dev, "driver: '%s': %s: bound to device\n", dev->driver->name,
454 __func__);
455
456 klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
457 device_links_driver_bound(dev);
458
459 device_pm_check_callbacks(dev);
460
461 /*
462 * Make sure the device is no longer in one of the deferred lists and
463 * kick off retrying all pending devices
464 */
465 driver_deferred_probe_del(dev);
466 driver_deferred_probe_trigger();
467
468 bus_notify(dev, BUS_NOTIFY_BOUND_DRIVER);
469 kobject_uevent(&dev->kobj, KOBJ_BIND);
470}
471
472static ssize_t coredump_store(struct device *dev, struct device_attribute *attr,
473 const char *buf, size_t count)
474{
475 device_lock(dev);
476 dev->driver->coredump(dev);
477 device_unlock(dev);
478
479 return count;
480}
481static DEVICE_ATTR_WO(coredump);
482
483static int driver_sysfs_add(struct device *dev)
484{
485 int ret;
486
487 bus_notify(dev, BUS_NOTIFY_BIND_DRIVER);
488
489 ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
490 kobject_name(&dev->kobj));
491 if (ret)
492 goto fail;
493
494 ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
495 "driver");
496 if (ret)
497 goto rm_dev;
498
499 if (!IS_ENABLED(CONFIG_DEV_COREDUMP) || !dev->driver->coredump)
500 return 0;
501
502 ret = device_create_file(dev, &dev_attr_coredump);
503 if (!ret)
504 return 0;
505
506 sysfs_remove_link(&dev->kobj, "driver");
507
508rm_dev:
509 sysfs_remove_link(&dev->driver->p->kobj,
510 kobject_name(&dev->kobj));
511
512fail:
513 return ret;
514}
515
516static void driver_sysfs_remove(struct device *dev)
517{
518 struct device_driver *drv = dev->driver;
519
520 if (drv) {
521 if (drv->coredump)
522 device_remove_file(dev, &dev_attr_coredump);
523 sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
524 sysfs_remove_link(&dev->kobj, "driver");
525 }
526}
527
528/**
529 * device_bind_driver - bind a driver to one device.
530 * @dev: device.
531 *
532 * Allow manual attachment of a driver to a device.
533 * Caller must have already set @dev->driver.
534 *
535 * Note that this does not modify the bus reference count.
536 * Please verify that is accounted for before calling this.
537 * (It is ok to call with no other effort from a driver's probe() method.)
538 *
539 * This function must be called with the device lock held.
540 *
541 * Callers should prefer to use device_driver_attach() instead.
542 */
543int device_bind_driver(struct device *dev)
544{
545 int ret;
546
547 ret = driver_sysfs_add(dev);
548 if (!ret) {
549 device_links_force_bind(dev);
550 driver_bound(dev);
551 }
552 else
553 bus_notify(dev, BUS_NOTIFY_DRIVER_NOT_BOUND);
554 return ret;
555}
556EXPORT_SYMBOL_GPL(device_bind_driver);
557
558static atomic_t probe_count = ATOMIC_INIT(0);
559static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
560
561static ssize_t state_synced_store(struct device *dev,
562 struct device_attribute *attr,
563 const char *buf, size_t count)
564{
565 int ret = 0;
566
567 if (strcmp("1", buf))
568 return -EINVAL;
569
570 device_lock(dev);
571 if (!dev_test_and_set_state_synced(dev))
572 dev_sync_state(dev);
573 else
574 ret = -EINVAL;
575 device_unlock(dev);
576
577 return ret ? ret : count;
578}
579
580static ssize_t state_synced_show(struct device *dev,
581 struct device_attribute *attr, char *buf)
582{
583 bool val;
584
585 device_lock(dev);
586 val = dev_state_synced(dev);
587 device_unlock(dev);
588
589 return sysfs_emit(buf, "%u\n", val);
590}
591static DEVICE_ATTR_RW(state_synced);
592
593static void device_unbind_cleanup(struct device *dev)
594{
595 if (dev->driver->p_cb.post_unbind_rust)
596 dev->driver->p_cb.post_unbind_rust(dev);
597 devres_release_all(dev);
598 arch_teardown_dma_ops(dev);
599 kfree(dev->dma_range_map);
600 dev->dma_range_map = NULL;
601 device_set_driver(dev, NULL);
602 dev_set_drvdata(dev, NULL);
603 dev_pm_domain_detach(dev, dev->power.detach_power_off);
604 if (dev->pm_domain && dev->pm_domain->dismiss)
605 dev->pm_domain->dismiss(dev);
606 pm_runtime_reinit(dev);
607 dev_pm_set_driver_flags(dev, 0);
608}
609
610static void device_remove(struct device *dev)
611{
612 device_remove_file(dev, &dev_attr_state_synced);
613 device_remove_groups(dev, dev->driver->dev_groups);
614
615 if (dev->bus && dev->bus->remove)
616 dev->bus->remove(dev);
617 else if (dev->driver->remove)
618 dev->driver->remove(dev);
619}
620
621static int call_driver_probe(struct device *dev, const struct device_driver *drv)
622{
623 int ret = 0;
624
625 if (dev->bus->probe)
626 ret = dev->bus->probe(dev);
627 else if (drv->probe)
628 ret = drv->probe(dev);
629
630 switch (ret) {
631 case 0:
632 break;
633 case -EPROBE_DEFER:
634 /* Driver requested deferred probing */
635 dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
636 break;
637 case -ENODEV:
638 case -ENXIO:
639 dev_dbg(dev, "probe with driver %s rejects match %d\n",
640 drv->name, ret);
641 break;
642 default:
643 /* driver matched but the probe failed */
644 dev_err(dev, "probe with driver %s failed with error %d\n",
645 drv->name, ret);
646 break;
647 }
648
649 return ret;
650}
651
652static int really_probe(struct device *dev, const struct device_driver *drv)
653{
654 bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
655 !drv->suppress_bind_attrs;
656 int ret, link_ret;
657
658 if (defer_all_probes) {
659 /*
660 * Value of defer_all_probes can be set only by
661 * device_block_probing() which, in turn, will call
662 * wait_for_device_probe() right after that to avoid any races.
663 */
664 dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
665 return -EPROBE_DEFER;
666 }
667
668 link_ret = device_links_check_suppliers(dev);
669 if (link_ret == -EPROBE_DEFER)
670 return link_ret;
671
672 dev_dbg(dev, "bus: '%s': %s: probing driver %s with device\n",
673 drv->bus->name, __func__, drv->name);
674 if (!list_empty(&dev->devres_head)) {
675 dev_crit(dev, "Resources present before probing\n");
676 ret = -EBUSY;
677 goto done;
678 }
679
680re_probe:
681 device_set_driver(dev, drv);
682
683 /* If using pinctrl, bind pins now before probing */
684 ret = pinctrl_bind_pins(dev);
685 if (ret)
686 goto pinctrl_bind_failed;
687
688 if (dev->bus->dma_configure) {
689 ret = dev->bus->dma_configure(dev);
690 if (ret)
691 goto pinctrl_bind_failed;
692 }
693
694 ret = driver_sysfs_add(dev);
695 if (ret) {
696 dev_err(dev, "%s: driver_sysfs_add failed\n", __func__);
697 goto sysfs_failed;
698 }
699
700 if (dev->pm_domain && dev->pm_domain->activate) {
701 ret = dev->pm_domain->activate(dev);
702 if (ret)
703 goto probe_failed;
704 }
705
706 ret = call_driver_probe(dev, drv);
707 if (ret) {
708 /*
709 * If fw_devlink_best_effort is active (denoted by -EAGAIN), the
710 * device might actually probe properly once some of its missing
711 * suppliers have probed. So, treat this as if the driver
712 * returned -EPROBE_DEFER.
713 */
714 if (link_ret == -EAGAIN)
715 ret = -EPROBE_DEFER;
716
717 /*
718 * Return probe errors as positive values so that the callers
719 * can distinguish them from other errors.
720 */
721 ret = -ret;
722 goto probe_failed;
723 }
724
725 ret = device_add_groups(dev, drv->dev_groups);
726 if (ret) {
727 dev_err(dev, "device_add_groups() failed\n");
728 goto dev_groups_failed;
729 }
730
731 if (dev_has_sync_state(dev)) {
732 ret = device_create_file(dev, &dev_attr_state_synced);
733 if (ret) {
734 dev_err(dev, "state_synced sysfs add failed\n");
735 goto dev_sysfs_state_synced_failed;
736 }
737 }
738
739 if (test_remove) {
740 test_remove = false;
741
742 device_remove(dev);
743 driver_sysfs_remove(dev);
744 if (dev->bus && dev->bus->dma_cleanup)
745 dev->bus->dma_cleanup(dev);
746 device_unbind_cleanup(dev);
747
748 goto re_probe;
749 }
750
751 pinctrl_init_done(dev);
752
753 if (dev->pm_domain && dev->pm_domain->sync)
754 dev->pm_domain->sync(dev);
755
756 driver_bound(dev);
757 dev_dbg(dev, "bus: '%s': %s: bound device to driver %s\n",
758 drv->bus->name, __func__, drv->name);
759 goto done;
760
761dev_sysfs_state_synced_failed:
762dev_groups_failed:
763 device_remove(dev);
764probe_failed:
765 driver_sysfs_remove(dev);
766sysfs_failed:
767 bus_notify(dev, BUS_NOTIFY_DRIVER_NOT_BOUND);
768 if (dev->bus && dev->bus->dma_cleanup)
769 dev->bus->dma_cleanup(dev);
770pinctrl_bind_failed:
771 device_links_no_driver(dev);
772 device_unbind_cleanup(dev);
773done:
774 return ret;
775}
776
777/*
778 * For initcall_debug, show the driver probe time.
779 */
780static int really_probe_debug(struct device *dev, const struct device_driver *drv)
781{
782 ktime_t calltime, rettime;
783 int ret;
784
785 calltime = ktime_get();
786 ret = really_probe(dev, drv);
787 rettime = ktime_get();
788 /*
789 * Don't change this to pr_debug() because that requires
790 * CONFIG_DYNAMIC_DEBUG and we want a simple 'initcall_debug' on the
791 * kernel commandline to print this all the time at the debug level.
792 */
793 printk(KERN_DEBUG "probe of %s with driver %s returned %d after %lld usecs\n",
794 dev_name(dev), drv->name, ret, ktime_us_delta(rettime, calltime));
795 return ret;
796}
797
798/**
799 * driver_probe_done
800 * Determine if the probe sequence is finished or not.
801 *
802 * Should somehow figure out how to use a semaphore, not an atomic variable...
803 */
804bool __init driver_probe_done(void)
805{
806 int local_probe_count = atomic_read(&probe_count);
807
808 pr_debug("%s: probe_count = %d\n", __func__, local_probe_count);
809 return !local_probe_count;
810}
811
812/**
813 * wait_for_device_probe
814 * Wait for device probing to be completed.
815 */
816void wait_for_device_probe(void)
817{
818 /* wait for the deferred probe workqueue to finish */
819 flush_work(&deferred_probe_work);
820
821 /* wait for the known devices to complete their probing */
822 wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
823 async_synchronize_full();
824}
825EXPORT_SYMBOL_GPL(wait_for_device_probe);
826
827static int __driver_probe_device(const struct device_driver *drv, struct device *dev)
828{
829 int ret = 0;
830
831 if (dev->p->dead || !device_is_registered(dev))
832 return -ENODEV;
833 if (dev->driver)
834 return -EBUSY;
835
836 /*
837 * In device_add(), the "struct device" gets linked into the subsystem's
838 * list of devices and broadcast to userspace (via uevent) before we're
839 * quite ready to probe. Those open pathways to driver probe before
840 * we've finished enough of device_add() to reliably support probe.
841 * Detect this and tell other pathways to try again later. device_add()
842 * itself will also try to probe immediately after setting
843 * "ready_to_probe".
844 */
845 if (!dev_ready_to_probe(dev))
846 return dev_err_probe(dev, -EPROBE_DEFER, "Device not ready to probe\n");
847
848 /*
849 * Call dev_set_can_match() after calling dev_ready_to_probe(), so
850 * driver_deferred_probe_add() won't actually add the device to the
851 * deferred probe list when dev_ready_to_probe() returns false.
852 *
853 * When dev_ready_to_probe() returns false, it means that device_add()
854 * will do another probe() attempt for us.
855 */
856 dev_set_can_match(dev);
857 dev_dbg(dev, "bus: '%s': %s: matched device with driver %s\n",
858 drv->bus->name, __func__, drv->name);
859
860 pm_runtime_get_suppliers(dev);
861 if (dev->parent)
862 pm_runtime_get_sync(dev->parent);
863
864 pm_runtime_barrier(dev);
865 if (initcall_debug)
866 ret = really_probe_debug(dev, drv);
867 else
868 ret = really_probe(dev, drv);
869 pm_request_idle(dev);
870
871 if (dev->parent)
872 pm_runtime_put(dev->parent);
873
874 pm_runtime_put_suppliers(dev);
875 return ret;
876}
877
878/**
879 * driver_probe_device - attempt to bind device & driver together
880 * @drv: driver to bind a device to
881 * @dev: device to try to bind to the driver
882 *
883 * This function returns -ENODEV if the device is not registered, -EBUSY if it
884 * already has a driver, 0 if the device is bound successfully and a positive
885 * (inverted) error code for failures from the ->probe method.
886 *
887 * This function must be called with @dev lock held. When called for a
888 * USB interface, @dev->parent lock must be held as well.
889 *
890 * If the device has a parent, runtime-resume the parent before driver probing.
891 */
892static int driver_probe_device(const struct device_driver *drv, struct device *dev)
893{
894 int trigger_count = atomic_read(&deferred_trigger_count);
895 int ret;
896
897 atomic_inc(&probe_count);
898 ret = __driver_probe_device(drv, dev);
899 if (ret == -EPROBE_DEFER || ret == EPROBE_DEFER) {
900 driver_deferred_probe_add(dev);
901
902 /*
903 * Did a trigger occur while probing? Need to re-trigger if yes
904 */
905 if (trigger_count != atomic_read(&deferred_trigger_count) &&
906 !defer_all_probes)
907 driver_deferred_probe_trigger();
908 }
909 atomic_dec(&probe_count);
910 wake_up_all(&probe_waitqueue);
911 return ret;
912}
913
914static inline bool cmdline_requested_async_probing(const char *drv_name)
915{
916 bool async_drv;
917
918 async_drv = parse_option_str(async_probe_drv_names, drv_name);
919
920 return (async_probe_default != async_drv);
921}
922
923/* The option format is "driver_async_probe=drv_name1,drv_name2,..." */
924static int __init save_async_options(char *buf)
925{
926 if (strlen(buf) >= ASYNC_DRV_NAMES_MAX_LEN)
927 pr_warn("Too long list of driver names for 'driver_async_probe'!\n");
928
929 strscpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN);
930 async_probe_default = parse_option_str(async_probe_drv_names, "*");
931
932 return 1;
933}
934__setup("driver_async_probe=", save_async_options);
935
936static bool driver_allows_async_probing(const struct device_driver *drv)
937{
938 switch (drv->probe_type) {
939 case PROBE_PREFER_ASYNCHRONOUS:
940 return true;
941
942 case PROBE_FORCE_SYNCHRONOUS:
943 return false;
944
945 default:
946 if (cmdline_requested_async_probing(drv->name))
947 return true;
948
949 if (module_requested_async_probing(drv->owner))
950 return true;
951
952 return false;
953 }
954}
955
956struct device_attach_data {
957 struct device *dev;
958
959 /*
960 * Indicates whether we are considering asynchronous probing or
961 * not. Only initial binding after device or driver registration
962 * (including deferral processing) may be done asynchronously, the
963 * rest is always synchronous, as we expect it is being done by
964 * request from userspace.
965 */
966 bool check_async;
967
968 /*
969 * Indicates if we are binding synchronous or asynchronous drivers.
970 * When asynchronous probing is enabled we'll execute 2 passes
971 * over drivers: first pass doing synchronous probing and second
972 * doing asynchronous probing (if synchronous did not succeed -
973 * most likely because there was no driver requiring synchronous
974 * probing - and we found asynchronous driver during first pass).
975 * The 2 passes are done because we can't shoot asynchronous
976 * probe for given device and driver from bus_for_each_drv() since
977 * driver pointer is not guaranteed to stay valid once
978 * bus_for_each_drv() iterates to the next driver on the bus.
979 */
980 bool want_async;
981
982 /*
983 * We'll set have_async to 'true' if, while scanning for matching
984 * driver, we'll encounter one that requests asynchronous probing.
985 */
986 bool have_async;
987};
988
989static int __device_attach_driver(struct device_driver *drv, void *_data)
990{
991 struct device_attach_data *data = _data;
992 struct device *dev = data->dev;
993 bool async_allowed;
994 int ret;
995
996 ret = driver_match_device(drv, dev);
997 if (ret == 0) {
998 /* no match */
999 return 0;
1000 } else if (ret == -EPROBE_DEFER) {
1001 dev_dbg(dev, "Device match requests probe deferral\n");
1002 dev_set_can_match(dev);
1003 driver_deferred_probe_add(dev);
1004 /*
1005 * Device can't match with a driver right now, so don't attempt
1006 * to match or bind with other drivers on the bus.
1007 */
1008 return ret;
1009 } else if (ret < 0) {
1010 dev_dbg(dev, "Bus failed to match device: %d\n", ret);
1011 return ret;
1012 } /* ret > 0 means positive match */
1013
1014 async_allowed = driver_allows_async_probing(drv);
1015
1016 if (async_allowed)
1017 data->have_async = true;
1018
1019 if (data->check_async && async_allowed != data->want_async)
1020 return 0;
1021
1022 /*
1023 * Ignore errors returned by ->probe so that the next driver can try
1024 * its luck.
1025 */
1026 ret = driver_probe_device(drv, dev);
1027 if (ret < 0)
1028 return ret;
1029 return ret == 0;
1030}
1031
1032static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
1033{
1034 struct device *dev = _dev;
1035 struct device_attach_data data = {
1036 .dev = dev,
1037 .check_async = true,
1038 .want_async = true,
1039 };
1040
1041 device_lock(dev);
1042
1043 /*
1044 * Check if device has already been removed or claimed. This may
1045 * happen with driver loading, device discovery/registration,
1046 * and deferred probe processing happens all at once with
1047 * multiple threads.
1048 */
1049 if (dev->p->dead || dev->driver)
1050 goto out_unlock;
1051
1052 if (dev->parent)
1053 pm_runtime_get_sync(dev->parent);
1054
1055 bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver);
1056 dev_dbg(dev, "async probe completed\n");
1057
1058 pm_request_idle(dev);
1059
1060 if (dev->parent)
1061 pm_runtime_put(dev->parent);
1062out_unlock:
1063 device_unlock(dev);
1064
1065 put_device(dev);
1066}
1067
1068static int __device_attach(struct device *dev, bool allow_async)
1069{
1070 int ret = 0;
1071 bool async = false;
1072
1073 device_lock(dev);
1074 if (dev->p->dead) {
1075 goto out_unlock;
1076 } else if (dev->driver) {
1077 if (device_is_bound(dev)) {
1078 ret = 1;
1079 goto out_unlock;
1080 }
1081 ret = device_bind_driver(dev);
1082 if (ret == 0)
1083 ret = 1;
1084 else {
1085 device_set_driver(dev, NULL);
1086 ret = 0;
1087 }
1088 } else {
1089 struct device_attach_data data = {
1090 .dev = dev,
1091 .check_async = allow_async,
1092 .want_async = false,
1093 };
1094
1095 if (dev->parent)
1096 pm_runtime_get_sync(dev->parent);
1097
1098 ret = bus_for_each_drv(dev->bus, NULL, &data,
1099 __device_attach_driver);
1100 if (!ret && allow_async && data.have_async) {
1101 /*
1102 * If we could not find appropriate driver
1103 * synchronously and we are allowed to do
1104 * async probes and there are drivers that
1105 * want to probe asynchronously, we'll
1106 * try them.
1107 */
1108 dev_dbg(dev, "scheduling asynchronous probe\n");
1109 get_device(dev);
1110 async = true;
1111 } else {
1112 pm_request_idle(dev);
1113 }
1114
1115 if (dev->parent)
1116 pm_runtime_put(dev->parent);
1117 }
1118out_unlock:
1119 device_unlock(dev);
1120 if (async)
1121 async_schedule_dev(__device_attach_async_helper, dev);
1122 return ret;
1123}
1124
1125/**
1126 * device_attach - try to attach device to a driver.
1127 * @dev: device.
1128 *
1129 * Walk the list of drivers that the bus has and call
1130 * driver_probe_device() for each pair. If a compatible
1131 * pair is found, break out and return.
1132 *
1133 * Returns 1 if the device was bound to a driver;
1134 * 0 if no matching driver was found;
1135 * -ENODEV if the device is not registered.
1136 *
1137 * When called for a USB interface, @dev->parent lock must be held.
1138 */
1139int device_attach(struct device *dev)
1140{
1141 return __device_attach(dev, false);
1142}
1143EXPORT_SYMBOL_GPL(device_attach);
1144
1145void device_initial_probe(struct device *dev)
1146{
1147 struct subsys_private *sp = bus_to_subsys(dev->bus);
1148
1149 if (!sp)
1150 return;
1151
1152 if (sp->drivers_autoprobe)
1153 __device_attach(dev, true);
1154
1155 subsys_put(sp);
1156}
1157
1158/*
1159 * __device_driver_lock - acquire locks needed to manipulate dev->drv
1160 * @dev: Device we will update driver info for
1161 * @parent: Parent device. Needed if the bus requires parent lock
1162 *
1163 * This function will take the required locks for manipulating dev->drv.
1164 * Normally this will just be the @dev lock, but when called for a USB
1165 * interface, @parent lock will be held as well.
1166 */
1167static void __device_driver_lock(struct device *dev, struct device *parent)
1168{
1169 if (parent && dev->bus->need_parent_lock)
1170 device_lock(parent);
1171 device_lock(dev);
1172}
1173
1174/*
1175 * __device_driver_unlock - release locks needed to manipulate dev->drv
1176 * @dev: Device we will update driver info for
1177 * @parent: Parent device. Needed if the bus requires parent lock
1178 *
1179 * This function will release the required locks for manipulating dev->drv.
1180 * Normally this will just be the @dev lock, but when called for a
1181 * USB interface, @parent lock will be released as well.
1182 */
1183static void __device_driver_unlock(struct device *dev, struct device *parent)
1184{
1185 device_unlock(dev);
1186 if (parent && dev->bus->need_parent_lock)
1187 device_unlock(parent);
1188}
1189
1190/**
1191 * device_driver_attach - attach a specific driver to a specific device
1192 * @drv: Driver to attach
1193 * @dev: Device to attach it to
1194 *
1195 * Manually attach driver to a device. Will acquire both @dev lock and
1196 * @dev->parent lock if needed. Returns 0 on success, -ERR on failure.
1197 */
1198int device_driver_attach(const struct device_driver *drv, struct device *dev)
1199{
1200 int ret;
1201
1202 __device_driver_lock(dev, dev->parent);
1203 ret = __driver_probe_device(drv, dev);
1204 __device_driver_unlock(dev, dev->parent);
1205
1206 /* also return probe errors as normal negative errnos */
1207 if (ret > 0)
1208 ret = -ret;
1209 if (ret == -EPROBE_DEFER)
1210 return -EAGAIN;
1211 return ret;
1212}
1213EXPORT_SYMBOL_GPL(device_driver_attach);
1214
1215static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie)
1216{
1217 struct device *dev = _dev;
1218 const struct device_driver *drv;
1219 int ret;
1220
1221 __device_driver_lock(dev, dev->parent);
1222 drv = dev->p->async_driver;
1223 dev->p->async_driver = NULL;
1224 ret = driver_probe_device(drv, dev);
1225 __device_driver_unlock(dev, dev->parent);
1226
1227 dev_dbg(dev, "driver %s async attach completed: %d\n", drv->name, ret);
1228
1229 put_device(dev);
1230}
1231
1232static int __driver_attach(struct device *dev, void *data)
1233{
1234 const struct device_driver *drv = data;
1235 bool async = false;
1236 int ret;
1237
1238 /*
1239 * Lock device and try to bind to it. We drop the error
1240 * here and always return 0, because we need to keep trying
1241 * to bind to devices and some drivers will return an error
1242 * simply if it didn't support the device.
1243 *
1244 * driver_probe_device() will spit a warning if there
1245 * is an error.
1246 */
1247
1248 ret = driver_match_device(drv, dev);
1249 if (ret == 0) {
1250 /* no match */
1251 return 0;
1252 } else if (ret == -EPROBE_DEFER) {
1253 dev_dbg(dev, "Device match requests probe deferral\n");
1254 dev_set_can_match(dev);
1255 driver_deferred_probe_add(dev);
1256 /*
1257 * Driver could not match with device, but may match with
1258 * another device on the bus.
1259 */
1260 return 0;
1261 } else if (ret < 0) {
1262 dev_dbg(dev, "Bus failed to match device: %d\n", ret);
1263 /*
1264 * Driver could not match with device, but may match with
1265 * another device on the bus.
1266 */
1267 return 0;
1268 } /* ret > 0 means positive match */
1269
1270 if (driver_allows_async_probing(drv)) {
1271 /*
1272 * Instead of probing the device synchronously we will
1273 * probe it asynchronously to allow for more parallelism.
1274 *
1275 * We only take the device lock here in order to guarantee
1276 * that the dev->driver and async_driver fields are protected
1277 */
1278 dev_dbg(dev, "probing driver %s asynchronously\n", drv->name);
1279 device_lock(dev);
1280 if (!dev->driver && !dev->p->async_driver) {
1281 get_device(dev);
1282 dev->p->async_driver = drv;
1283 async = true;
1284 }
1285 device_unlock(dev);
1286 if (async)
1287 async_schedule_dev(__driver_attach_async_helper, dev);
1288 return 0;
1289 }
1290
1291 __device_driver_lock(dev, dev->parent);
1292 driver_probe_device(drv, dev);
1293 __device_driver_unlock(dev, dev->parent);
1294
1295 return 0;
1296}
1297
1298/**
1299 * driver_attach - try to bind driver to devices.
1300 * @drv: driver.
1301 *
1302 * Walk the list of devices that the bus has on it and try to
1303 * match the driver with each one. If driver_probe_device()
1304 * returns 0 and the @dev->driver is set, we've found a
1305 * compatible pair.
1306 */
1307int driver_attach(const struct device_driver *drv)
1308{
1309 /* The (void *) will be put back to const * in __driver_attach() */
1310 return bus_for_each_dev(drv->bus, NULL, (void *)drv, __driver_attach);
1311}
1312EXPORT_SYMBOL_GPL(driver_attach);
1313
1314/*
1315 * __device_release_driver() must be called with @dev lock held.
1316 * When called for a USB interface, @dev->parent lock must be held as well.
1317 */
1318static void __device_release_driver(struct device *dev, struct device *parent)
1319{
1320 struct device_driver *drv;
1321
1322 drv = dev->driver;
1323 if (drv) {
1324 pm_runtime_get_sync(dev);
1325
1326 while (device_links_busy(dev)) {
1327 __device_driver_unlock(dev, parent);
1328
1329 device_links_unbind_consumers(dev);
1330
1331 __device_driver_lock(dev, parent);
1332 /*
1333 * A concurrent invocation of the same function might
1334 * have released the driver successfully while this one
1335 * was waiting, so check for that.
1336 */
1337 if (dev->driver != drv) {
1338 pm_runtime_put(dev);
1339 return;
1340 }
1341 }
1342
1343 driver_sysfs_remove(dev);
1344
1345 bus_notify(dev, BUS_NOTIFY_UNBIND_DRIVER);
1346
1347 pm_runtime_put_sync(dev);
1348
1349 device_remove(dev);
1350
1351 if (dev->bus && dev->bus->dma_cleanup)
1352 dev->bus->dma_cleanup(dev);
1353
1354 device_unbind_cleanup(dev);
1355 device_links_driver_cleanup(dev);
1356
1357 klist_remove(&dev->p->knode_driver);
1358 device_pm_check_callbacks(dev);
1359
1360 bus_notify(dev, BUS_NOTIFY_UNBOUND_DRIVER);
1361 kobject_uevent(&dev->kobj, KOBJ_UNBIND);
1362 }
1363}
1364
1365void device_release_driver_internal(struct device *dev,
1366 const struct device_driver *drv,
1367 struct device *parent)
1368{
1369 __device_driver_lock(dev, parent);
1370
1371 if (!drv || drv == dev->driver)
1372 __device_release_driver(dev, parent);
1373
1374 __device_driver_unlock(dev, parent);
1375}
1376
1377/**
1378 * device_release_driver - manually detach device from driver.
1379 * @dev: device.
1380 *
1381 * Manually detach device from driver.
1382 * When called for a USB interface, @dev->parent lock must be held.
1383 *
1384 * If this function is to be called with @dev->parent lock held, ensure that
1385 * the device's consumers are unbound in advance or that their locks can be
1386 * acquired under the @dev->parent lock.
1387 */
1388void device_release_driver(struct device *dev)
1389{
1390 /*
1391 * If anyone calls device_release_driver() recursively from
1392 * within their ->remove callback for the same device, they
1393 * will deadlock right here.
1394 */
1395 device_release_driver_internal(dev, NULL, NULL);
1396}
1397EXPORT_SYMBOL_GPL(device_release_driver);
1398
1399/**
1400 * device_driver_detach - detach driver from a specific device
1401 * @dev: device to detach driver from
1402 *
1403 * Detach driver from device. Will acquire both @dev lock and @dev->parent
1404 * lock if needed.
1405 */
1406void device_driver_detach(struct device *dev)
1407{
1408 device_release_driver_internal(dev, NULL, dev->parent);
1409}
1410
1411/**
1412 * driver_detach - detach driver from all devices it controls.
1413 * @drv: driver.
1414 */
1415void driver_detach(const struct device_driver *drv)
1416{
1417 struct device_private *dev_prv;
1418 struct device *dev;
1419
1420 if (driver_allows_async_probing(drv))
1421 async_synchronize_full();
1422
1423 for (;;) {
1424 spin_lock(&drv->p->klist_devices.k_lock);
1425 if (list_empty(&drv->p->klist_devices.k_list)) {
1426 spin_unlock(&drv->p->klist_devices.k_lock);
1427 break;
1428 }
1429 dev_prv = list_last_entry(&drv->p->klist_devices.k_list,
1430 struct device_private,
1431 knode_driver.n_node);
1432 dev = dev_prv->device;
1433 get_device(dev);
1434 spin_unlock(&drv->p->klist_devices.k_lock);
1435 device_release_driver_internal(dev, drv, dev->parent);
1436 put_device(dev);
1437 }
1438}