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 bool initcalls_done;
59 :
60 : /* Save the async probe drivers' name from kernel cmdline */
61 : #define ASYNC_DRV_NAMES_MAX_LEN 256
62 : static char async_probe_drv_names[ASYNC_DRV_NAMES_MAX_LEN];
63 :
64 : /*
65 : * In some cases, like suspend to RAM or hibernation, It might be reasonable
66 : * to prohibit probing of devices as it could be unsafe.
67 : * Once defer_all_probes is true all drivers probes will be forcibly deferred.
68 : */
69 : static bool defer_all_probes;
70 :
71 : static void __device_set_deferred_probe_reason(const struct device *dev, char *reason)
72 : {
73 0 : kfree(dev->p->deferred_probe_reason);
74 0 : dev->p->deferred_probe_reason = reason;
75 : }
76 :
77 : /*
78 : * deferred_probe_work_func() - Retry probing devices in the active list.
79 : */
80 2 : static void deferred_probe_work_func(struct work_struct *work)
81 : {
82 : struct device *dev;
83 : struct device_private *private;
84 : /*
85 : * This block processes every device in the deferred 'active' list.
86 : * Each device is removed from the active list and passed to
87 : * bus_probe_device() to re-attempt the probe. The loop continues
88 : * until every device in the active list is removed and retried.
89 : *
90 : * Note: Once the device is removed from the list and the mutex is
91 : * released, it is possible for the device get freed by another thread
92 : * and cause a illegal pointer dereference. This code uses
93 : * get/put_device() to ensure the device structure cannot disappear
94 : * from under our feet.
95 : */
96 2 : mutex_lock(&deferred_probe_mutex);
97 4 : while (!list_empty(&deferred_probe_active_list)) {
98 0 : private = list_first_entry(&deferred_probe_active_list,
99 : typeof(*dev->p), deferred_probe);
100 0 : dev = private->device;
101 0 : list_del_init(&private->deferred_probe);
102 :
103 0 : get_device(dev);
104 :
105 0 : __device_set_deferred_probe_reason(dev, NULL);
106 :
107 : /*
108 : * Drop the mutex while probing each device; the probe path may
109 : * manipulate the deferred list
110 : */
111 0 : mutex_unlock(&deferred_probe_mutex);
112 :
113 : /*
114 : * Force the device to the end of the dpm_list since
115 : * the PM code assumes that the order we add things to
116 : * the list is a good order for suspend but deferred
117 : * probe makes that very unsafe.
118 : */
119 0 : device_pm_move_to_tail(dev);
120 :
121 : dev_dbg(dev, "Retrying from deferred list\n");
122 0 : bus_probe_device(dev);
123 0 : mutex_lock(&deferred_probe_mutex);
124 :
125 0 : put_device(dev);
126 : }
127 2 : mutex_unlock(&deferred_probe_mutex);
128 2 : }
129 : static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
130 :
131 0 : void driver_deferred_probe_add(struct device *dev)
132 : {
133 0 : if (!dev->can_match)
134 : return;
135 :
136 0 : mutex_lock(&deferred_probe_mutex);
137 0 : if (list_empty(&dev->p->deferred_probe)) {
138 : dev_dbg(dev, "Added to deferred list\n");
139 0 : list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
140 : }
141 0 : mutex_unlock(&deferred_probe_mutex);
142 : }
143 :
144 0 : void driver_deferred_probe_del(struct device *dev)
145 : {
146 0 : mutex_lock(&deferred_probe_mutex);
147 0 : if (!list_empty(&dev->p->deferred_probe)) {
148 : dev_dbg(dev, "Removed from deferred list\n");
149 0 : list_del_init(&dev->p->deferred_probe);
150 0 : __device_set_deferred_probe_reason(dev, NULL);
151 : }
152 0 : mutex_unlock(&deferred_probe_mutex);
153 0 : }
154 :
155 : static bool driver_deferred_probe_enable;
156 : /**
157 : * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
158 : *
159 : * This functions moves all devices from the pending list to the active
160 : * list and schedules the deferred probe workqueue to process them. It
161 : * should be called anytime a driver is successfully bound to a device.
162 : *
163 : * Note, there is a race condition in multi-threaded probe. In the case where
164 : * more than one device is probing at the same time, it is possible for one
165 : * probe to complete successfully while another is about to defer. If the second
166 : * depends on the first, then it will get put on the pending list after the
167 : * trigger event has already occurred and will be stuck there.
168 : *
169 : * The atomic 'deferred_trigger_count' is used to determine if a successful
170 : * trigger has occurred in the midst of probing a driver. If the trigger count
171 : * changes in the midst of a probe, then deferred processing should be triggered
172 : * again.
173 : */
174 2 : static void driver_deferred_probe_trigger(void)
175 : {
176 2 : if (!driver_deferred_probe_enable)
177 : return;
178 :
179 : /*
180 : * A successful probe means that all the devices in the pending list
181 : * should be triggered to be reprobed. Move all the deferred devices
182 : * into the active list so they can be retried by the workqueue
183 : */
184 2 : mutex_lock(&deferred_probe_mutex);
185 2 : atomic_inc(&deferred_trigger_count);
186 2 : list_splice_tail_init(&deferred_probe_pending_list,
187 : &deferred_probe_active_list);
188 2 : mutex_unlock(&deferred_probe_mutex);
189 :
190 : /*
191 : * Kick the re-probe thread. It may already be scheduled, but it is
192 : * safe to kick it again.
193 : */
194 2 : queue_work(system_unbound_wq, &deferred_probe_work);
195 : }
196 :
197 : /**
198 : * device_block_probing() - Block/defer device's probes
199 : *
200 : * It will disable probing of devices and defer their probes instead.
201 : */
202 1 : void device_block_probing(void)
203 : {
204 1 : defer_all_probes = true;
205 : /* sync with probes to avoid races. */
206 1 : wait_for_device_probe();
207 1 : }
208 :
209 : /**
210 : * device_unblock_probing() - Unblock/enable device's probes
211 : *
212 : * It will restore normal behavior and trigger re-probing of deferred
213 : * devices.
214 : */
215 0 : void device_unblock_probing(void)
216 : {
217 0 : defer_all_probes = false;
218 0 : driver_deferred_probe_trigger();
219 0 : }
220 :
221 : /**
222 : * device_set_deferred_probe_reason() - Set defer probe reason message for device
223 : * @dev: the pointer to the struct device
224 : * @vaf: the pointer to va_format structure with message
225 : */
226 0 : void device_set_deferred_probe_reason(const struct device *dev, struct va_format *vaf)
227 : {
228 0 : const char *drv = dev_driver_string(dev);
229 : char *reason;
230 :
231 0 : mutex_lock(&deferred_probe_mutex);
232 :
233 0 : reason = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf);
234 0 : __device_set_deferred_probe_reason(dev, reason);
235 :
236 0 : mutex_unlock(&deferred_probe_mutex);
237 0 : }
238 :
239 : /*
240 : * deferred_devs_show() - Show the devices in the deferred probe pending list.
241 : */
242 : static int deferred_devs_show(struct seq_file *s, void *data)
243 : {
244 : struct device_private *curr;
245 :
246 : mutex_lock(&deferred_probe_mutex);
247 :
248 : list_for_each_entry(curr, &deferred_probe_pending_list, deferred_probe)
249 : seq_printf(s, "%s\t%s", dev_name(curr->device),
250 : curr->device->p->deferred_probe_reason ?: "\n");
251 :
252 : mutex_unlock(&deferred_probe_mutex);
253 :
254 : return 0;
255 : }
256 : DEFINE_SHOW_ATTRIBUTE(deferred_devs);
257 :
258 : int driver_deferred_probe_timeout;
259 : EXPORT_SYMBOL_GPL(driver_deferred_probe_timeout);
260 : static DECLARE_WAIT_QUEUE_HEAD(probe_timeout_waitqueue);
261 :
262 0 : static int __init deferred_probe_timeout_setup(char *str)
263 : {
264 : int timeout;
265 :
266 0 : if (!kstrtoint(str, 10, &timeout))
267 0 : driver_deferred_probe_timeout = timeout;
268 0 : 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 : */
285 0 : int driver_deferred_probe_check_state(struct device *dev)
286 : {
287 0 : if (!IS_ENABLED(CONFIG_MODULES) && initcalls_done) {
288 0 : dev_warn(dev, "ignoring dependency for device, assuming no driver\n");
289 0 : 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 : }
299 : EXPORT_SYMBOL_GPL(driver_deferred_probe_check_state);
300 :
301 0 : static void deferred_probe_timeout_work_func(struct work_struct *work)
302 : {
303 : struct device_private *p;
304 :
305 0 : fw_devlink_drivers_done();
306 :
307 0 : driver_deferred_probe_timeout = 0;
308 0 : driver_deferred_probe_trigger();
309 0 : flush_work(&deferred_probe_work);
310 :
311 0 : mutex_lock(&deferred_probe_mutex);
312 0 : list_for_each_entry(p, &deferred_probe_pending_list, deferred_probe)
313 0 : dev_info(p->device, "deferred probe pending\n");
314 0 : mutex_unlock(&deferred_probe_mutex);
315 0 : wake_up_all(&probe_timeout_waitqueue);
316 0 : }
317 : static DECLARE_DELAYED_WORK(deferred_probe_timeout_work, deferred_probe_timeout_work_func);
318 :
319 : /**
320 : * deferred_probe_initcall() - Enable probing of deferred devices
321 : *
322 : * We don't want to get in the way when the bulk of drivers are getting probed.
323 : * Instead, this initcall makes sure that deferred probing is delayed until
324 : * late_initcall time.
325 : */
326 1 : static int deferred_probe_initcall(void)
327 : {
328 1 : debugfs_create_file("devices_deferred", 0444, NULL, NULL,
329 : &deferred_devs_fops);
330 :
331 1 : driver_deferred_probe_enable = true;
332 1 : driver_deferred_probe_trigger();
333 : /* Sort as many dependencies as possible before exiting initcalls */
334 1 : flush_work(&deferred_probe_work);
335 1 : initcalls_done = true;
336 :
337 : if (!IS_ENABLED(CONFIG_MODULES))
338 1 : fw_devlink_drivers_done();
339 :
340 : /*
341 : * Trigger deferred probe again, this time we won't defer anything
342 : * that is optional
343 : */
344 1 : driver_deferred_probe_trigger();
345 1 : flush_work(&deferred_probe_work);
346 :
347 1 : if (driver_deferred_probe_timeout > 0) {
348 0 : schedule_delayed_work(&deferred_probe_timeout_work,
349 0 : driver_deferred_probe_timeout * HZ);
350 : }
351 1 : return 0;
352 : }
353 : late_initcall(deferred_probe_initcall);
354 :
355 0 : static void __exit deferred_probe_exit(void)
356 : {
357 0 : debugfs_remove_recursive(debugfs_lookup("devices_deferred", NULL));
358 0 : }
359 : __exitcall(deferred_probe_exit);
360 :
361 : /**
362 : * device_is_bound() - Check if device is bound to a driver
363 : * @dev: device to check
364 : *
365 : * Returns true if passed device has already finished probing successfully
366 : * against a driver.
367 : *
368 : * This function must be called with the device lock held.
369 : */
370 0 : bool device_is_bound(struct device *dev)
371 : {
372 0 : return dev->p && klist_node_attached(&dev->p->knode_driver);
373 : }
374 :
375 0 : static void driver_bound(struct device *dev)
376 : {
377 0 : if (device_is_bound(dev)) {
378 0 : pr_warn("%s: device %s already bound\n",
379 : __func__, kobject_name(&dev->kobj));
380 0 : return;
381 : }
382 :
383 : pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->driver->name,
384 : __func__, dev_name(dev));
385 :
386 0 : klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
387 0 : device_links_driver_bound(dev);
388 :
389 0 : device_pm_check_callbacks(dev);
390 :
391 : /*
392 : * Make sure the device is no longer in one of the deferred lists and
393 : * kick off retrying all pending devices
394 : */
395 0 : driver_deferred_probe_del(dev);
396 0 : driver_deferred_probe_trigger();
397 :
398 0 : if (dev->bus)
399 0 : blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
400 : BUS_NOTIFY_BOUND_DRIVER, dev);
401 :
402 0 : kobject_uevent(&dev->kobj, KOBJ_BIND);
403 : }
404 :
405 0 : static ssize_t coredump_store(struct device *dev, struct device_attribute *attr,
406 : const char *buf, size_t count)
407 : {
408 0 : device_lock(dev);
409 0 : dev->driver->coredump(dev);
410 0 : device_unlock(dev);
411 :
412 0 : return count;
413 : }
414 : static DEVICE_ATTR_WO(coredump);
415 :
416 0 : static int driver_sysfs_add(struct device *dev)
417 : {
418 : int ret;
419 :
420 0 : if (dev->bus)
421 0 : blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
422 : BUS_NOTIFY_BIND_DRIVER, dev);
423 :
424 0 : ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
425 0 : kobject_name(&dev->kobj));
426 0 : if (ret)
427 : goto fail;
428 :
429 0 : ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
430 : "driver");
431 0 : if (ret)
432 : goto rm_dev;
433 :
434 : if (!IS_ENABLED(CONFIG_DEV_COREDUMP) || !dev->driver->coredump)
435 : return 0;
436 :
437 : ret = device_create_file(dev, &dev_attr_coredump);
438 : if (!ret)
439 : return 0;
440 :
441 : sysfs_remove_link(&dev->kobj, "driver");
442 :
443 : rm_dev:
444 0 : sysfs_remove_link(&dev->driver->p->kobj,
445 0 : kobject_name(&dev->kobj));
446 :
447 : fail:
448 : return ret;
449 : }
450 :
451 0 : static void driver_sysfs_remove(struct device *dev)
452 : {
453 0 : struct device_driver *drv = dev->driver;
454 :
455 0 : if (drv) {
456 0 : if (drv->coredump)
457 0 : device_remove_file(dev, &dev_attr_coredump);
458 0 : sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
459 0 : sysfs_remove_link(&dev->kobj, "driver");
460 : }
461 0 : }
462 :
463 : /**
464 : * device_bind_driver - bind a driver to one device.
465 : * @dev: device.
466 : *
467 : * Allow manual attachment of a driver to a device.
468 : * Caller must have already set @dev->driver.
469 : *
470 : * Note that this does not modify the bus reference count.
471 : * Please verify that is accounted for before calling this.
472 : * (It is ok to call with no other effort from a driver's probe() method.)
473 : *
474 : * This function must be called with the device lock held.
475 : *
476 : * Callers should prefer to use device_driver_attach() instead.
477 : */
478 0 : int device_bind_driver(struct device *dev)
479 : {
480 : int ret;
481 :
482 0 : ret = driver_sysfs_add(dev);
483 0 : if (!ret) {
484 0 : device_links_force_bind(dev);
485 0 : driver_bound(dev);
486 : }
487 0 : else if (dev->bus)
488 0 : blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
489 : BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
490 0 : return ret;
491 : }
492 : EXPORT_SYMBOL_GPL(device_bind_driver);
493 :
494 : static atomic_t probe_count = ATOMIC_INIT(0);
495 : static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
496 :
497 0 : static ssize_t state_synced_show(struct device *dev,
498 : struct device_attribute *attr, char *buf)
499 : {
500 : bool val;
501 :
502 0 : device_lock(dev);
503 0 : val = dev->state_synced;
504 0 : device_unlock(dev);
505 :
506 0 : return sysfs_emit(buf, "%u\n", val);
507 : }
508 : static DEVICE_ATTR_RO(state_synced);
509 :
510 0 : static void device_unbind_cleanup(struct device *dev)
511 : {
512 0 : devres_release_all(dev);
513 0 : arch_teardown_dma_ops(dev);
514 0 : kfree(dev->dma_range_map);
515 0 : dev->dma_range_map = NULL;
516 0 : dev->driver = NULL;
517 0 : dev_set_drvdata(dev, NULL);
518 0 : if (dev->pm_domain && dev->pm_domain->dismiss)
519 0 : dev->pm_domain->dismiss(dev);
520 0 : pm_runtime_reinit(dev);
521 0 : dev_pm_set_driver_flags(dev, 0);
522 0 : }
523 :
524 0 : static void device_remove(struct device *dev)
525 : {
526 0 : device_remove_file(dev, &dev_attr_state_synced);
527 0 : device_remove_groups(dev, dev->driver->dev_groups);
528 :
529 0 : if (dev->bus && dev->bus->remove)
530 0 : dev->bus->remove(dev);
531 0 : else if (dev->driver->remove)
532 0 : dev->driver->remove(dev);
533 0 : }
534 :
535 0 : static int call_driver_probe(struct device *dev, struct device_driver *drv)
536 : {
537 0 : int ret = 0;
538 :
539 0 : if (dev->bus->probe)
540 0 : ret = dev->bus->probe(dev);
541 0 : else if (drv->probe)
542 0 : ret = drv->probe(dev);
543 :
544 0 : switch (ret) {
545 : case 0:
546 : break;
547 : case -EPROBE_DEFER:
548 : /* Driver requested deferred probing */
549 : dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
550 : break;
551 : case -ENODEV:
552 : case -ENXIO:
553 : pr_debug("%s: probe of %s rejects match %d\n",
554 : drv->name, dev_name(dev), ret);
555 : break;
556 : default:
557 : /* driver matched but the probe failed */
558 0 : pr_warn("%s: probe of %s failed with error %d\n",
559 : drv->name, dev_name(dev), ret);
560 : break;
561 : }
562 :
563 0 : return ret;
564 : }
565 :
566 0 : static int really_probe(struct device *dev, struct device_driver *drv)
567 : {
568 0 : bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
569 : !drv->suppress_bind_attrs;
570 : int ret;
571 :
572 0 : if (defer_all_probes) {
573 : /*
574 : * Value of defer_all_probes can be set only by
575 : * device_block_probing() which, in turn, will call
576 : * wait_for_device_probe() right after that to avoid any races.
577 : */
578 : dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
579 : return -EPROBE_DEFER;
580 : }
581 :
582 0 : ret = device_links_check_suppliers(dev);
583 0 : if (ret)
584 : return ret;
585 :
586 : pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
587 : drv->bus->name, __func__, drv->name, dev_name(dev));
588 0 : if (!list_empty(&dev->devres_head)) {
589 0 : dev_crit(dev, "Resources present before probing\n");
590 0 : ret = -EBUSY;
591 0 : goto done;
592 : }
593 :
594 : re_probe:
595 0 : dev->driver = drv;
596 :
597 : /* If using pinctrl, bind pins now before probing */
598 0 : ret = pinctrl_bind_pins(dev);
599 : if (ret)
600 : goto pinctrl_bind_failed;
601 :
602 0 : if (dev->bus->dma_configure) {
603 0 : ret = dev->bus->dma_configure(dev);
604 0 : if (ret)
605 : goto pinctrl_bind_failed;
606 : }
607 :
608 0 : ret = driver_sysfs_add(dev);
609 0 : if (ret) {
610 0 : pr_err("%s: driver_sysfs_add(%s) failed\n",
611 : __func__, dev_name(dev));
612 0 : goto sysfs_failed;
613 : }
614 :
615 0 : if (dev->pm_domain && dev->pm_domain->activate) {
616 0 : ret = dev->pm_domain->activate(dev);
617 0 : if (ret)
618 : goto probe_failed;
619 : }
620 :
621 0 : ret = call_driver_probe(dev, drv);
622 0 : if (ret) {
623 : /*
624 : * Return probe errors as positive values so that the callers
625 : * can distinguish them from other errors.
626 : */
627 0 : ret = -ret;
628 0 : goto probe_failed;
629 : }
630 :
631 0 : ret = device_add_groups(dev, drv->dev_groups);
632 0 : if (ret) {
633 0 : dev_err(dev, "device_add_groups() failed\n");
634 0 : goto dev_groups_failed;
635 : }
636 :
637 0 : if (dev_has_sync_state(dev)) {
638 0 : ret = device_create_file(dev, &dev_attr_state_synced);
639 0 : if (ret) {
640 0 : dev_err(dev, "state_synced sysfs add failed\n");
641 0 : goto dev_sysfs_state_synced_failed;
642 : }
643 : }
644 :
645 : if (test_remove) {
646 : test_remove = false;
647 :
648 : device_remove(dev);
649 : driver_sysfs_remove(dev);
650 : device_unbind_cleanup(dev);
651 :
652 : goto re_probe;
653 : }
654 :
655 0 : pinctrl_init_done(dev);
656 :
657 0 : if (dev->pm_domain && dev->pm_domain->sync)
658 0 : dev->pm_domain->sync(dev);
659 :
660 0 : driver_bound(dev);
661 : pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
662 : drv->bus->name, __func__, dev_name(dev), drv->name);
663 0 : goto done;
664 :
665 : dev_sysfs_state_synced_failed:
666 : dev_groups_failed:
667 0 : device_remove(dev);
668 : probe_failed:
669 0 : driver_sysfs_remove(dev);
670 : sysfs_failed:
671 0 : if (dev->bus)
672 0 : blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
673 : BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
674 : pinctrl_bind_failed:
675 0 : device_links_no_driver(dev);
676 0 : device_unbind_cleanup(dev);
677 : done:
678 : return ret;
679 : }
680 :
681 : /*
682 : * For initcall_debug, show the driver probe time.
683 : */
684 : static int really_probe_debug(struct device *dev, struct device_driver *drv)
685 : {
686 : ktime_t calltime, rettime;
687 : int ret;
688 :
689 0 : calltime = ktime_get();
690 0 : ret = really_probe(dev, drv);
691 0 : rettime = ktime_get();
692 : pr_debug("probe of %s returned %d after %lld usecs\n",
693 : dev_name(dev), ret, ktime_us_delta(rettime, calltime));
694 : return ret;
695 : }
696 :
697 : /**
698 : * driver_probe_done
699 : * Determine if the probe sequence is finished or not.
700 : *
701 : * Should somehow figure out how to use a semaphore, not an atomic variable...
702 : */
703 0 : int driver_probe_done(void)
704 : {
705 0 : int local_probe_count = atomic_read(&probe_count);
706 :
707 : pr_debug("%s: probe_count = %d\n", __func__, local_probe_count);
708 0 : if (local_probe_count)
709 : return -EBUSY;
710 0 : return 0;
711 : }
712 :
713 : /**
714 : * wait_for_device_probe
715 : * Wait for device probing to be completed.
716 : */
717 2 : void wait_for_device_probe(void)
718 : {
719 : /* wait for probe timeout */
720 2 : wait_event(probe_timeout_waitqueue, !driver_deferred_probe_timeout);
721 :
722 : /* wait for the deferred probe workqueue to finish */
723 2 : flush_work(&deferred_probe_work);
724 :
725 : /* wait for the known devices to complete their probing */
726 2 : wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
727 2 : async_synchronize_full();
728 2 : }
729 : EXPORT_SYMBOL_GPL(wait_for_device_probe);
730 :
731 0 : static int __driver_probe_device(struct device_driver *drv, struct device *dev)
732 : {
733 0 : int ret = 0;
734 :
735 0 : if (dev->p->dead || !device_is_registered(dev))
736 : return -ENODEV;
737 0 : if (dev->driver)
738 : return -EBUSY;
739 :
740 0 : dev->can_match = true;
741 : pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
742 : drv->bus->name, __func__, dev_name(dev), drv->name);
743 :
744 0 : pm_runtime_get_suppliers(dev);
745 0 : if (dev->parent)
746 0 : pm_runtime_get_sync(dev->parent);
747 :
748 0 : pm_runtime_barrier(dev);
749 0 : if (initcall_debug)
750 0 : ret = really_probe_debug(dev, drv);
751 : else
752 0 : ret = really_probe(dev, drv);
753 0 : pm_request_idle(dev);
754 :
755 0 : if (dev->parent)
756 0 : pm_runtime_put(dev->parent);
757 :
758 0 : pm_runtime_put_suppliers(dev);
759 0 : return ret;
760 : }
761 :
762 : /**
763 : * driver_probe_device - attempt to bind device & driver together
764 : * @drv: driver to bind a device to
765 : * @dev: device to try to bind to the driver
766 : *
767 : * This function returns -ENODEV if the device is not registered, -EBUSY if it
768 : * already has a driver, 0 if the device is bound successfully and a positive
769 : * (inverted) error code for failures from the ->probe method.
770 : *
771 : * This function must be called with @dev lock held. When called for a
772 : * USB interface, @dev->parent lock must be held as well.
773 : *
774 : * If the device has a parent, runtime-resume the parent before driver probing.
775 : */
776 0 : static int driver_probe_device(struct device_driver *drv, struct device *dev)
777 : {
778 0 : int trigger_count = atomic_read(&deferred_trigger_count);
779 : int ret;
780 :
781 0 : atomic_inc(&probe_count);
782 0 : ret = __driver_probe_device(drv, dev);
783 0 : if (ret == -EPROBE_DEFER || ret == EPROBE_DEFER) {
784 0 : driver_deferred_probe_add(dev);
785 :
786 : /*
787 : * Did a trigger occur while probing? Need to re-trigger if yes
788 : */
789 0 : if (trigger_count != atomic_read(&deferred_trigger_count) &&
790 0 : !defer_all_probes)
791 0 : driver_deferred_probe_trigger();
792 : }
793 0 : atomic_dec(&probe_count);
794 0 : wake_up_all(&probe_waitqueue);
795 0 : return ret;
796 : }
797 :
798 : static inline bool cmdline_requested_async_probing(const char *drv_name)
799 : {
800 1 : return parse_option_str(async_probe_drv_names, drv_name);
801 : }
802 :
803 : /* The option format is "driver_async_probe=drv_name1,drv_name2,..." */
804 0 : static int __init save_async_options(char *buf)
805 : {
806 0 : if (strlen(buf) >= ASYNC_DRV_NAMES_MAX_LEN)
807 0 : pr_warn("Too long list of driver names for 'driver_async_probe'!\n");
808 :
809 0 : strlcpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN);
810 0 : return 1;
811 : }
812 : __setup("driver_async_probe=", save_async_options);
813 :
814 1 : bool driver_allows_async_probing(struct device_driver *drv)
815 : {
816 1 : switch (drv->probe_type) {
817 : case PROBE_PREFER_ASYNCHRONOUS:
818 : return true;
819 :
820 : case PROBE_FORCE_SYNCHRONOUS:
821 0 : return false;
822 :
823 : default:
824 2 : if (cmdline_requested_async_probing(drv->name))
825 : return true;
826 :
827 1 : if (module_requested_async_probing(drv->owner))
828 : return true;
829 :
830 1 : return false;
831 : }
832 : }
833 :
834 : struct device_attach_data {
835 : struct device *dev;
836 :
837 : /*
838 : * Indicates whether we are considering asynchronous probing or
839 : * not. Only initial binding after device or driver registration
840 : * (including deferral processing) may be done asynchronously, the
841 : * rest is always synchronous, as we expect it is being done by
842 : * request from userspace.
843 : */
844 : bool check_async;
845 :
846 : /*
847 : * Indicates if we are binding synchronous or asynchronous drivers.
848 : * When asynchronous probing is enabled we'll execute 2 passes
849 : * over drivers: first pass doing synchronous probing and second
850 : * doing asynchronous probing (if synchronous did not succeed -
851 : * most likely because there was no driver requiring synchronous
852 : * probing - and we found asynchronous driver during first pass).
853 : * The 2 passes are done because we can't shoot asynchronous
854 : * probe for given device and driver from bus_for_each_drv() since
855 : * driver pointer is not guaranteed to stay valid once
856 : * bus_for_each_drv() iterates to the next driver on the bus.
857 : */
858 : bool want_async;
859 :
860 : /*
861 : * We'll set have_async to 'true' if, while scanning for matching
862 : * driver, we'll encounter one that requests asynchronous probing.
863 : */
864 : bool have_async;
865 : };
866 :
867 0 : static int __device_attach_driver(struct device_driver *drv, void *_data)
868 : {
869 0 : struct device_attach_data *data = _data;
870 0 : struct device *dev = data->dev;
871 : bool async_allowed;
872 : int ret;
873 :
874 0 : ret = driver_match_device(drv, dev);
875 0 : if (ret == 0) {
876 : /* no match */
877 : return 0;
878 0 : } else if (ret == -EPROBE_DEFER) {
879 : dev_dbg(dev, "Device match requests probe deferral\n");
880 0 : dev->can_match = true;
881 0 : driver_deferred_probe_add(dev);
882 0 : } else if (ret < 0) {
883 : dev_dbg(dev, "Bus failed to match device: %d\n", ret);
884 : return ret;
885 : } /* ret > 0 means positive match */
886 :
887 0 : async_allowed = driver_allows_async_probing(drv);
888 :
889 0 : if (async_allowed)
890 0 : data->have_async = true;
891 :
892 0 : if (data->check_async && async_allowed != data->want_async)
893 : return 0;
894 :
895 : /*
896 : * Ignore errors returned by ->probe so that the next driver can try
897 : * its luck.
898 : */
899 0 : ret = driver_probe_device(drv, dev);
900 0 : if (ret < 0)
901 : return ret;
902 0 : return ret == 0;
903 : }
904 :
905 0 : static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
906 : {
907 0 : struct device *dev = _dev;
908 0 : struct device_attach_data data = {
909 : .dev = dev,
910 : .check_async = true,
911 : .want_async = true,
912 : };
913 :
914 0 : device_lock(dev);
915 :
916 : /*
917 : * Check if device has already been removed or claimed. This may
918 : * happen with driver loading, device discovery/registration,
919 : * and deferred probe processing happens all at once with
920 : * multiple threads.
921 : */
922 0 : if (dev->p->dead || dev->driver)
923 : goto out_unlock;
924 :
925 0 : if (dev->parent)
926 0 : pm_runtime_get_sync(dev->parent);
927 :
928 0 : bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver);
929 : dev_dbg(dev, "async probe completed\n");
930 :
931 0 : pm_request_idle(dev);
932 :
933 0 : if (dev->parent)
934 0 : pm_runtime_put(dev->parent);
935 : out_unlock:
936 0 : device_unlock(dev);
937 :
938 0 : put_device(dev);
939 0 : }
940 :
941 4 : static int __device_attach(struct device *dev, bool allow_async)
942 : {
943 4 : int ret = 0;
944 :
945 4 : device_lock(dev);
946 4 : if (dev->p->dead) {
947 : goto out_unlock;
948 4 : } else if (dev->driver) {
949 0 : if (device_is_bound(dev)) {
950 : ret = 1;
951 : goto out_unlock;
952 : }
953 0 : ret = device_bind_driver(dev);
954 0 : if (ret == 0)
955 : ret = 1;
956 : else {
957 0 : dev->driver = NULL;
958 0 : ret = 0;
959 : }
960 : } else {
961 4 : struct device_attach_data data = {
962 : .dev = dev,
963 : .check_async = allow_async,
964 : .want_async = false,
965 : };
966 :
967 4 : if (dev->parent)
968 0 : pm_runtime_get_sync(dev->parent);
969 :
970 4 : ret = bus_for_each_drv(dev->bus, NULL, &data,
971 : __device_attach_driver);
972 4 : if (!ret && allow_async && data.have_async) {
973 : /*
974 : * If we could not find appropriate driver
975 : * synchronously and we are allowed to do
976 : * async probes and there are drivers that
977 : * want to probe asynchronously, we'll
978 : * try them.
979 : */
980 : dev_dbg(dev, "scheduling asynchronous probe\n");
981 0 : get_device(dev);
982 : async_schedule_dev(__device_attach_async_helper, dev);
983 : } else {
984 : pm_request_idle(dev);
985 : }
986 :
987 4 : if (dev->parent)
988 0 : pm_runtime_put(dev->parent);
989 : }
990 : out_unlock:
991 4 : device_unlock(dev);
992 4 : return ret;
993 : }
994 :
995 : /**
996 : * device_attach - try to attach device to a driver.
997 : * @dev: device.
998 : *
999 : * Walk the list of drivers that the bus has and call
1000 : * driver_probe_device() for each pair. If a compatible
1001 : * pair is found, break out and return.
1002 : *
1003 : * Returns 1 if the device was bound to a driver;
1004 : * 0 if no matching driver was found;
1005 : * -ENODEV if the device is not registered.
1006 : *
1007 : * When called for a USB interface, @dev->parent lock must be held.
1008 : */
1009 0 : int device_attach(struct device *dev)
1010 : {
1011 0 : return __device_attach(dev, false);
1012 : }
1013 : EXPORT_SYMBOL_GPL(device_attach);
1014 :
1015 4 : void device_initial_probe(struct device *dev)
1016 : {
1017 4 : __device_attach(dev, true);
1018 4 : }
1019 :
1020 : /*
1021 : * __device_driver_lock - acquire locks needed to manipulate dev->drv
1022 : * @dev: Device we will update driver info for
1023 : * @parent: Parent device. Needed if the bus requires parent lock
1024 : *
1025 : * This function will take the required locks for manipulating dev->drv.
1026 : * Normally this will just be the @dev lock, but when called for a USB
1027 : * interface, @parent lock will be held as well.
1028 : */
1029 0 : static void __device_driver_lock(struct device *dev, struct device *parent)
1030 : {
1031 0 : if (parent && dev->bus->need_parent_lock)
1032 : device_lock(parent);
1033 0 : device_lock(dev);
1034 0 : }
1035 :
1036 : /*
1037 : * __device_driver_unlock - release locks needed to manipulate dev->drv
1038 : * @dev: Device we will update driver info for
1039 : * @parent: Parent device. Needed if the bus requires parent lock
1040 : *
1041 : * This function will release the required locks for manipulating dev->drv.
1042 : * Normally this will just be the @dev lock, but when called for a
1043 : * USB interface, @parent lock will be released as well.
1044 : */
1045 0 : static void __device_driver_unlock(struct device *dev, struct device *parent)
1046 : {
1047 0 : device_unlock(dev);
1048 0 : if (parent && dev->bus->need_parent_lock)
1049 : device_unlock(parent);
1050 0 : }
1051 :
1052 : /**
1053 : * device_driver_attach - attach a specific driver to a specific device
1054 : * @drv: Driver to attach
1055 : * @dev: Device to attach it to
1056 : *
1057 : * Manually attach driver to a device. Will acquire both @dev lock and
1058 : * @dev->parent lock if needed. Returns 0 on success, -ERR on failure.
1059 : */
1060 0 : int device_driver_attach(struct device_driver *drv, struct device *dev)
1061 : {
1062 : int ret;
1063 :
1064 0 : __device_driver_lock(dev, dev->parent);
1065 0 : ret = __driver_probe_device(drv, dev);
1066 0 : __device_driver_unlock(dev, dev->parent);
1067 :
1068 : /* also return probe errors as normal negative errnos */
1069 0 : if (ret > 0)
1070 0 : ret = -ret;
1071 0 : if (ret == -EPROBE_DEFER)
1072 : return -EAGAIN;
1073 0 : return ret;
1074 : }
1075 : EXPORT_SYMBOL_GPL(device_driver_attach);
1076 :
1077 0 : static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie)
1078 : {
1079 0 : struct device *dev = _dev;
1080 : struct device_driver *drv;
1081 : int ret;
1082 :
1083 0 : __device_driver_lock(dev, dev->parent);
1084 0 : drv = dev->p->async_driver;
1085 0 : ret = driver_probe_device(drv, dev);
1086 0 : __device_driver_unlock(dev, dev->parent);
1087 :
1088 : dev_dbg(dev, "driver %s async attach completed: %d\n", drv->name, ret);
1089 :
1090 0 : put_device(dev);
1091 0 : }
1092 :
1093 0 : static int __driver_attach(struct device *dev, void *data)
1094 : {
1095 0 : struct device_driver *drv = data;
1096 : int ret;
1097 :
1098 : /*
1099 : * Lock device and try to bind to it. We drop the error
1100 : * here and always return 0, because we need to keep trying
1101 : * to bind to devices and some drivers will return an error
1102 : * simply if it didn't support the device.
1103 : *
1104 : * driver_probe_device() will spit a warning if there
1105 : * is an error.
1106 : */
1107 :
1108 0 : ret = driver_match_device(drv, dev);
1109 0 : if (ret == 0) {
1110 : /* no match */
1111 : return 0;
1112 0 : } else if (ret == -EPROBE_DEFER) {
1113 : dev_dbg(dev, "Device match requests probe deferral\n");
1114 0 : dev->can_match = true;
1115 0 : driver_deferred_probe_add(dev);
1116 0 : } else if (ret < 0) {
1117 : dev_dbg(dev, "Bus failed to match device: %d\n", ret);
1118 : return ret;
1119 : } /* ret > 0 means positive match */
1120 :
1121 0 : if (driver_allows_async_probing(drv)) {
1122 : /*
1123 : * Instead of probing the device synchronously we will
1124 : * probe it asynchronously to allow for more parallelism.
1125 : *
1126 : * We only take the device lock here in order to guarantee
1127 : * that the dev->driver and async_driver fields are protected
1128 : */
1129 : dev_dbg(dev, "probing driver %s asynchronously\n", drv->name);
1130 0 : device_lock(dev);
1131 0 : if (!dev->driver) {
1132 0 : get_device(dev);
1133 0 : dev->p->async_driver = drv;
1134 : async_schedule_dev(__driver_attach_async_helper, dev);
1135 : }
1136 0 : device_unlock(dev);
1137 0 : return 0;
1138 : }
1139 :
1140 0 : __device_driver_lock(dev, dev->parent);
1141 0 : driver_probe_device(drv, dev);
1142 0 : __device_driver_unlock(dev, dev->parent);
1143 :
1144 0 : return 0;
1145 : }
1146 :
1147 : /**
1148 : * driver_attach - try to bind driver to devices.
1149 : * @drv: driver.
1150 : *
1151 : * Walk the list of devices that the bus has on it and try to
1152 : * match the driver with each one. If driver_probe_device()
1153 : * returns 0 and the @dev->driver is set, we've found a
1154 : * compatible pair.
1155 : */
1156 19 : int driver_attach(struct device_driver *drv)
1157 : {
1158 19 : return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
1159 : }
1160 : EXPORT_SYMBOL_GPL(driver_attach);
1161 :
1162 : /*
1163 : * __device_release_driver() must be called with @dev lock held.
1164 : * When called for a USB interface, @dev->parent lock must be held as well.
1165 : */
1166 0 : static void __device_release_driver(struct device *dev, struct device *parent)
1167 : {
1168 : struct device_driver *drv;
1169 :
1170 0 : drv = dev->driver;
1171 0 : if (drv) {
1172 : pm_runtime_get_sync(dev);
1173 :
1174 0 : while (device_links_busy(dev)) {
1175 0 : __device_driver_unlock(dev, parent);
1176 :
1177 0 : device_links_unbind_consumers(dev);
1178 :
1179 0 : __device_driver_lock(dev, parent);
1180 : /*
1181 : * A concurrent invocation of the same function might
1182 : * have released the driver successfully while this one
1183 : * was waiting, so check for that.
1184 : */
1185 0 : if (dev->driver != drv) {
1186 : pm_runtime_put(dev);
1187 : return;
1188 : }
1189 : }
1190 :
1191 0 : driver_sysfs_remove(dev);
1192 :
1193 0 : if (dev->bus)
1194 0 : blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1195 : BUS_NOTIFY_UNBIND_DRIVER,
1196 : dev);
1197 :
1198 0 : pm_runtime_put_sync(dev);
1199 :
1200 0 : device_remove(dev);
1201 :
1202 0 : device_links_driver_cleanup(dev);
1203 0 : device_unbind_cleanup(dev);
1204 :
1205 0 : klist_remove(&dev->p->knode_driver);
1206 0 : device_pm_check_callbacks(dev);
1207 0 : if (dev->bus)
1208 0 : blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1209 : BUS_NOTIFY_UNBOUND_DRIVER,
1210 : dev);
1211 :
1212 0 : kobject_uevent(&dev->kobj, KOBJ_UNBIND);
1213 : }
1214 : }
1215 :
1216 0 : void device_release_driver_internal(struct device *dev,
1217 : struct device_driver *drv,
1218 : struct device *parent)
1219 : {
1220 0 : __device_driver_lock(dev, parent);
1221 :
1222 0 : if (!drv || drv == dev->driver)
1223 0 : __device_release_driver(dev, parent);
1224 :
1225 0 : __device_driver_unlock(dev, parent);
1226 0 : }
1227 :
1228 : /**
1229 : * device_release_driver - manually detach device from driver.
1230 : * @dev: device.
1231 : *
1232 : * Manually detach device from driver.
1233 : * When called for a USB interface, @dev->parent lock must be held.
1234 : *
1235 : * If this function is to be called with @dev->parent lock held, ensure that
1236 : * the device's consumers are unbound in advance or that their locks can be
1237 : * acquired under the @dev->parent lock.
1238 : */
1239 0 : void device_release_driver(struct device *dev)
1240 : {
1241 : /*
1242 : * If anyone calls device_release_driver() recursively from
1243 : * within their ->remove callback for the same device, they
1244 : * will deadlock right here.
1245 : */
1246 0 : device_release_driver_internal(dev, NULL, NULL);
1247 0 : }
1248 : EXPORT_SYMBOL_GPL(device_release_driver);
1249 :
1250 : /**
1251 : * device_driver_detach - detach driver from a specific device
1252 : * @dev: device to detach driver from
1253 : *
1254 : * Detach driver from device. Will acquire both @dev lock and @dev->parent
1255 : * lock if needed.
1256 : */
1257 0 : void device_driver_detach(struct device *dev)
1258 : {
1259 0 : device_release_driver_internal(dev, NULL, dev->parent);
1260 0 : }
1261 :
1262 : /**
1263 : * driver_detach - detach driver from all devices it controls.
1264 : * @drv: driver.
1265 : */
1266 1 : void driver_detach(struct device_driver *drv)
1267 : {
1268 : struct device_private *dev_prv;
1269 : struct device *dev;
1270 :
1271 1 : if (driver_allows_async_probing(drv))
1272 0 : async_synchronize_full();
1273 :
1274 : for (;;) {
1275 2 : spin_lock(&drv->p->klist_devices.k_lock);
1276 2 : if (list_empty(&drv->p->klist_devices.k_list)) {
1277 2 : spin_unlock(&drv->p->klist_devices.k_lock);
1278 : break;
1279 : }
1280 0 : dev_prv = list_last_entry(&drv->p->klist_devices.k_list,
1281 : struct device_private,
1282 : knode_driver.n_node);
1283 0 : dev = dev_prv->device;
1284 0 : get_device(dev);
1285 0 : spin_unlock(&drv->p->klist_devices.k_lock);
1286 0 : device_release_driver_internal(dev, drv, dev->parent);
1287 0 : put_device(dev);
1288 : }
1289 1 : }
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