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 : static bool async_probe_default;
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 : static void __device_set_deferred_probe_reason(const struct device *dev, char *reason)
73 : {
74 0 : kfree(dev->p->deferred_probe_reason);
75 0 : dev->p->deferred_probe_reason = reason;
76 : }
77 :
78 : /*
79 : * deferred_probe_work_func() - Retry probing devices in the active list.
80 : */
81 19 : static void deferred_probe_work_func(struct work_struct *work)
82 : {
83 : struct device *dev;
84 : struct device_private *private;
85 : /*
86 : * This block processes every device in the deferred 'active' list.
87 : * Each device is removed from the active list and passed to
88 : * bus_probe_device() to re-attempt the probe. The loop continues
89 : * until every device in the active list is removed and retried.
90 : *
91 : * Note: Once the device is removed from the list and the mutex is
92 : * released, it is possible for the device get freed by another thread
93 : * and cause a illegal pointer dereference. This code uses
94 : * get/put_device() to ensure the device structure cannot disappear
95 : * from under our feet.
96 : */
97 19 : mutex_lock(&deferred_probe_mutex);
98 38 : while (!list_empty(&deferred_probe_active_list)) {
99 0 : private = list_first_entry(&deferred_probe_active_list,
100 : typeof(*dev->p), deferred_probe);
101 0 : dev = private->device;
102 0 : list_del_init(&private->deferred_probe);
103 :
104 0 : get_device(dev);
105 :
106 0 : __device_set_deferred_probe_reason(dev, NULL);
107 :
108 : /*
109 : * Drop the mutex while probing each device; the probe path may
110 : * manipulate the deferred list
111 : */
112 0 : mutex_unlock(&deferred_probe_mutex);
113 :
114 : /*
115 : * Force the device to the end of the dpm_list since
116 : * the PM code assumes that the order we add things to
117 : * the list is a good order for suspend but deferred
118 : * probe makes that very unsafe.
119 : */
120 0 : device_pm_move_to_tail(dev);
121 :
122 : dev_dbg(dev, "Retrying from deferred list\n");
123 0 : bus_probe_device(dev);
124 0 : mutex_lock(&deferred_probe_mutex);
125 :
126 0 : put_device(dev);
127 : }
128 19 : mutex_unlock(&deferred_probe_mutex);
129 19 : }
130 : static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
131 :
132 0 : void driver_deferred_probe_add(struct device *dev)
133 : {
134 0 : if (!dev->can_match)
135 : return;
136 :
137 0 : mutex_lock(&deferred_probe_mutex);
138 0 : if (list_empty(&dev->p->deferred_probe)) {
139 : dev_dbg(dev, "Added to deferred list\n");
140 0 : list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
141 : }
142 0 : mutex_unlock(&deferred_probe_mutex);
143 : }
144 :
145 35 : void driver_deferred_probe_del(struct device *dev)
146 : {
147 35 : mutex_lock(&deferred_probe_mutex);
148 70 : if (!list_empty(&dev->p->deferred_probe)) {
149 : dev_dbg(dev, "Removed from deferred list\n");
150 0 : list_del_init(&dev->p->deferred_probe);
151 0 : __device_set_deferred_probe_reason(dev, NULL);
152 : }
153 35 : mutex_unlock(&deferred_probe_mutex);
154 35 : }
155 :
156 : static bool driver_deferred_probe_enable;
157 : /**
158 : * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
159 : *
160 : * This functions moves all devices from the pending list to the active
161 : * list and schedules the deferred probe workqueue to process them. It
162 : * should be called anytime a driver is successfully bound to a device.
163 : *
164 : * Note, there is a race condition in multi-threaded probe. In the case where
165 : * more than one device is probing at the same time, it is possible for one
166 : * probe to complete successfully while another is about to defer. If the second
167 : * depends on the first, then it will get put on the pending list after the
168 : * trigger event has already occurred and will be stuck there.
169 : *
170 : * The atomic 'deferred_trigger_count' is used to determine if a successful
171 : * trigger has occurred in the midst of probing a driver. If the trigger count
172 : * changes in the midst of a probe, then deferred processing should be triggered
173 : * again.
174 : */
175 19 : void driver_deferred_probe_trigger(void)
176 : {
177 19 : if (!driver_deferred_probe_enable)
178 : return;
179 :
180 : /*
181 : * A successful probe means that all the devices in the pending list
182 : * should be triggered to be reprobed. Move all the deferred devices
183 : * into the active list so they can be retried by the workqueue
184 : */
185 19 : mutex_lock(&deferred_probe_mutex);
186 19 : atomic_inc(&deferred_trigger_count);
187 19 : list_splice_tail_init(&deferred_probe_pending_list,
188 : &deferred_probe_active_list);
189 19 : mutex_unlock(&deferred_probe_mutex);
190 :
191 : /*
192 : * Kick the re-probe thread. It may already be scheduled, but it is
193 : * safe to kick it again.
194 : */
195 19 : queue_work(system_unbound_wq, &deferred_probe_work);
196 : }
197 :
198 : /**
199 : * device_block_probing() - Block/defer device's probes
200 : *
201 : * It will disable probing of devices and defer their probes instead.
202 : */
203 1 : void device_block_probing(void)
204 : {
205 1 : defer_all_probes = true;
206 : /* sync with probes to avoid races. */
207 1 : wait_for_device_probe();
208 1 : }
209 :
210 : /**
211 : * device_unblock_probing() - Unblock/enable device's probes
212 : *
213 : * It will restore normal behavior and trigger re-probing of deferred
214 : * devices.
215 : */
216 0 : void device_unblock_probing(void)
217 : {
218 0 : defer_all_probes = false;
219 0 : driver_deferred_probe_trigger();
220 0 : }
221 :
222 : /**
223 : * device_set_deferred_probe_reason() - Set defer probe reason message for device
224 : * @dev: the pointer to the struct device
225 : * @vaf: the pointer to va_format structure with message
226 : */
227 0 : void device_set_deferred_probe_reason(const struct device *dev, struct va_format *vaf)
228 : {
229 0 : const char *drv = dev_driver_string(dev);
230 : char *reason;
231 :
232 0 : mutex_lock(&deferred_probe_mutex);
233 :
234 0 : reason = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf);
235 0 : __device_set_deferred_probe_reason(dev, reason);
236 :
237 0 : mutex_unlock(&deferred_probe_mutex);
238 0 : }
239 :
240 : /*
241 : * deferred_devs_show() - Show the devices in the deferred probe pending list.
242 : */
243 : static int deferred_devs_show(struct seq_file *s, void *data)
244 : {
245 : struct device_private *curr;
246 :
247 : mutex_lock(&deferred_probe_mutex);
248 :
249 : list_for_each_entry(curr, &deferred_probe_pending_list, deferred_probe)
250 : seq_printf(s, "%s\t%s", dev_name(curr->device),
251 : curr->device->p->deferred_probe_reason ?: "\n");
252 :
253 : mutex_unlock(&deferred_probe_mutex);
254 :
255 : return 0;
256 : }
257 : DEFINE_SHOW_ATTRIBUTE(deferred_devs);
258 :
259 : #ifdef CONFIG_MODULES
260 : static int driver_deferred_probe_timeout = 10;
261 : #else
262 : static int driver_deferred_probe_timeout;
263 : #endif
264 :
265 0 : static int __init deferred_probe_timeout_setup(char *str)
266 : {
267 : int timeout;
268 :
269 0 : if (!kstrtoint(str, 10, &timeout))
270 0 : driver_deferred_probe_timeout = timeout;
271 0 : return 1;
272 : }
273 : __setup("deferred_probe_timeout=", deferred_probe_timeout_setup);
274 :
275 : /**
276 : * driver_deferred_probe_check_state() - Check deferred probe state
277 : * @dev: device to check
278 : *
279 : * Return:
280 : * * -ENODEV if initcalls have completed and modules are disabled.
281 : * * -ETIMEDOUT if the deferred probe timeout was set and has expired
282 : * and modules are enabled.
283 : * * -EPROBE_DEFER in other cases.
284 : *
285 : * Drivers or subsystems can opt-in to calling this function instead of directly
286 : * returning -EPROBE_DEFER.
287 : */
288 0 : int driver_deferred_probe_check_state(struct device *dev)
289 : {
290 0 : if (!IS_ENABLED(CONFIG_MODULES) && initcalls_done) {
291 0 : dev_warn(dev, "ignoring dependency for device, assuming no driver\n");
292 0 : return -ENODEV;
293 : }
294 :
295 : if (!driver_deferred_probe_timeout && initcalls_done) {
296 : dev_warn(dev, "deferred probe timeout, ignoring dependency\n");
297 : return -ETIMEDOUT;
298 : }
299 :
300 : return -EPROBE_DEFER;
301 : }
302 : EXPORT_SYMBOL_GPL(driver_deferred_probe_check_state);
303 :
304 0 : static void deferred_probe_timeout_work_func(struct work_struct *work)
305 : {
306 : struct device_private *p;
307 :
308 0 : fw_devlink_drivers_done();
309 :
310 0 : driver_deferred_probe_timeout = 0;
311 0 : driver_deferred_probe_trigger();
312 0 : flush_work(&deferred_probe_work);
313 :
314 0 : mutex_lock(&deferred_probe_mutex);
315 0 : list_for_each_entry(p, &deferred_probe_pending_list, deferred_probe)
316 0 : dev_info(p->device, "deferred probe pending\n");
317 0 : mutex_unlock(&deferred_probe_mutex);
318 0 : }
319 : static DECLARE_DELAYED_WORK(deferred_probe_timeout_work, deferred_probe_timeout_work_func);
320 :
321 33 : void deferred_probe_extend_timeout(void)
322 : {
323 : /*
324 : * If the work hasn't been queued yet or if the work expired, don't
325 : * start a new one.
326 : */
327 33 : if (cancel_delayed_work(&deferred_probe_timeout_work)) {
328 0 : schedule_delayed_work(&deferred_probe_timeout_work,
329 0 : driver_deferred_probe_timeout * HZ);
330 : pr_debug("Extended deferred probe timeout by %d secs\n",
331 : driver_deferred_probe_timeout);
332 : }
333 33 : }
334 :
335 : /**
336 : * deferred_probe_initcall() - Enable probing of deferred devices
337 : *
338 : * We don't want to get in the way when the bulk of drivers are getting probed.
339 : * Instead, this initcall makes sure that deferred probing is delayed until
340 : * late_initcall time.
341 : */
342 1 : static int deferred_probe_initcall(void)
343 : {
344 1 : debugfs_create_file("devices_deferred", 0444, NULL, NULL,
345 : &deferred_devs_fops);
346 :
347 1 : driver_deferred_probe_enable = true;
348 1 : driver_deferred_probe_trigger();
349 : /* Sort as many dependencies as possible before exiting initcalls */
350 1 : flush_work(&deferred_probe_work);
351 1 : initcalls_done = true;
352 :
353 : if (!IS_ENABLED(CONFIG_MODULES))
354 1 : fw_devlink_drivers_done();
355 :
356 : /*
357 : * Trigger deferred probe again, this time we won't defer anything
358 : * that is optional
359 : */
360 1 : driver_deferred_probe_trigger();
361 1 : flush_work(&deferred_probe_work);
362 :
363 1 : if (driver_deferred_probe_timeout > 0) {
364 0 : schedule_delayed_work(&deferred_probe_timeout_work,
365 0 : driver_deferred_probe_timeout * HZ);
366 : }
367 1 : return 0;
368 : }
369 : late_initcall(deferred_probe_initcall);
370 :
371 0 : static void __exit deferred_probe_exit(void)
372 : {
373 0 : debugfs_lookup_and_remove("devices_deferred", NULL);
374 0 : }
375 : __exitcall(deferred_probe_exit);
376 :
377 : /**
378 : * device_is_bound() - Check if device is bound to a driver
379 : * @dev: device to check
380 : *
381 : * Returns true if passed device has already finished probing successfully
382 : * against a driver.
383 : *
384 : * This function must be called with the device lock held.
385 : */
386 0 : bool device_is_bound(struct device *dev)
387 : {
388 17 : return dev->p && klist_node_attached(&dev->p->knode_driver);
389 : }
390 :
391 17 : static void driver_bound(struct device *dev)
392 : {
393 17 : if (device_is_bound(dev)) {
394 0 : pr_warn("%s: device %s already bound\n",
395 : __func__, kobject_name(&dev->kobj));
396 0 : return;
397 : }
398 :
399 : pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->driver->name,
400 : __func__, dev_name(dev));
401 :
402 17 : klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
403 17 : device_links_driver_bound(dev);
404 :
405 17 : device_pm_check_callbacks(dev);
406 :
407 : /*
408 : * Make sure the device is no longer in one of the deferred lists and
409 : * kick off retrying all pending devices
410 : */
411 17 : driver_deferred_probe_del(dev);
412 17 : driver_deferred_probe_trigger();
413 :
414 17 : bus_notify(dev, BUS_NOTIFY_BOUND_DRIVER);
415 17 : kobject_uevent(&dev->kobj, KOBJ_BIND);
416 : }
417 :
418 0 : static ssize_t coredump_store(struct device *dev, struct device_attribute *attr,
419 : const char *buf, size_t count)
420 : {
421 0 : device_lock(dev);
422 0 : dev->driver->coredump(dev);
423 0 : device_unlock(dev);
424 :
425 0 : return count;
426 : }
427 : static DEVICE_ATTR_WO(coredump);
428 :
429 17 : static int driver_sysfs_add(struct device *dev)
430 : {
431 : int ret;
432 :
433 17 : bus_notify(dev, BUS_NOTIFY_BIND_DRIVER);
434 :
435 17 : ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
436 17 : kobject_name(&dev->kobj));
437 17 : if (ret)
438 : goto fail;
439 :
440 17 : ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
441 : "driver");
442 17 : if (ret)
443 : goto rm_dev;
444 :
445 : if (!IS_ENABLED(CONFIG_DEV_COREDUMP) || !dev->driver->coredump)
446 : return 0;
447 :
448 : ret = device_create_file(dev, &dev_attr_coredump);
449 : if (!ret)
450 : return 0;
451 :
452 : sysfs_remove_link(&dev->kobj, "driver");
453 :
454 : rm_dev:
455 0 : sysfs_remove_link(&dev->driver->p->kobj,
456 0 : kobject_name(&dev->kobj));
457 :
458 : fail:
459 : return ret;
460 : }
461 :
462 17 : static void driver_sysfs_remove(struct device *dev)
463 : {
464 17 : struct device_driver *drv = dev->driver;
465 :
466 17 : if (drv) {
467 17 : if (drv->coredump)
468 0 : device_remove_file(dev, &dev_attr_coredump);
469 17 : sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
470 17 : sysfs_remove_link(&dev->kobj, "driver");
471 : }
472 17 : }
473 :
474 : /**
475 : * device_bind_driver - bind a driver to one device.
476 : * @dev: device.
477 : *
478 : * Allow manual attachment of a driver to a device.
479 : * Caller must have already set @dev->driver.
480 : *
481 : * Note that this does not modify the bus reference count.
482 : * Please verify that is accounted for before calling this.
483 : * (It is ok to call with no other effort from a driver's probe() method.)
484 : *
485 : * This function must be called with the device lock held.
486 : *
487 : * Callers should prefer to use device_driver_attach() instead.
488 : */
489 0 : int device_bind_driver(struct device *dev)
490 : {
491 : int ret;
492 :
493 0 : ret = driver_sysfs_add(dev);
494 0 : if (!ret) {
495 0 : device_links_force_bind(dev);
496 0 : driver_bound(dev);
497 : }
498 : else
499 0 : bus_notify(dev, BUS_NOTIFY_DRIVER_NOT_BOUND);
500 0 : return ret;
501 : }
502 : EXPORT_SYMBOL_GPL(device_bind_driver);
503 :
504 : static atomic_t probe_count = ATOMIC_INIT(0);
505 : static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
506 :
507 0 : static ssize_t state_synced_show(struct device *dev,
508 : struct device_attribute *attr, char *buf)
509 : {
510 : bool val;
511 :
512 0 : device_lock(dev);
513 0 : val = dev->state_synced;
514 0 : device_unlock(dev);
515 :
516 0 : return sysfs_emit(buf, "%u\n", val);
517 : }
518 : static DEVICE_ATTR_RO(state_synced);
519 :
520 17 : static void device_unbind_cleanup(struct device *dev)
521 : {
522 17 : devres_release_all(dev);
523 17 : arch_teardown_dma_ops(dev);
524 17 : kfree(dev->dma_range_map);
525 17 : dev->dma_range_map = NULL;
526 17 : dev->driver = NULL;
527 34 : dev_set_drvdata(dev, NULL);
528 17 : if (dev->pm_domain && dev->pm_domain->dismiss)
529 0 : dev->pm_domain->dismiss(dev);
530 17 : pm_runtime_reinit(dev);
531 34 : dev_pm_set_driver_flags(dev, 0);
532 17 : }
533 :
534 17 : static void device_remove(struct device *dev)
535 : {
536 17 : device_remove_file(dev, &dev_attr_state_synced);
537 17 : device_remove_groups(dev, dev->driver->dev_groups);
538 :
539 17 : if (dev->bus && dev->bus->remove)
540 17 : dev->bus->remove(dev);
541 0 : else if (dev->driver->remove)
542 0 : dev->driver->remove(dev);
543 17 : }
544 :
545 17 : static int call_driver_probe(struct device *dev, struct device_driver *drv)
546 : {
547 17 : int ret = 0;
548 :
549 17 : if (dev->bus->probe)
550 17 : ret = dev->bus->probe(dev);
551 0 : else if (drv->probe)
552 0 : ret = drv->probe(dev);
553 :
554 17 : switch (ret) {
555 : case 0:
556 : break;
557 : case -EPROBE_DEFER:
558 : /* Driver requested deferred probing */
559 : dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
560 : break;
561 : case -ENODEV:
562 : case -ENXIO:
563 : pr_debug("%s: probe of %s rejects match %d\n",
564 : drv->name, dev_name(dev), ret);
565 : break;
566 : default:
567 : /* driver matched but the probe failed */
568 0 : pr_warn("%s: probe of %s failed with error %d\n",
569 : drv->name, dev_name(dev), ret);
570 : break;
571 : }
572 :
573 17 : return ret;
574 : }
575 :
576 17 : static int really_probe(struct device *dev, struct device_driver *drv)
577 : {
578 17 : bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
579 : !drv->suppress_bind_attrs;
580 : int ret, link_ret;
581 :
582 17 : if (defer_all_probes) {
583 : /*
584 : * Value of defer_all_probes can be set only by
585 : * device_block_probing() which, in turn, will call
586 : * wait_for_device_probe() right after that to avoid any races.
587 : */
588 : dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
589 : return -EPROBE_DEFER;
590 : }
591 :
592 17 : link_ret = device_links_check_suppliers(dev);
593 17 : if (link_ret == -EPROBE_DEFER)
594 : return link_ret;
595 :
596 : pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
597 : drv->bus->name, __func__, drv->name, dev_name(dev));
598 34 : if (!list_empty(&dev->devres_head)) {
599 0 : dev_crit(dev, "Resources present before probing\n");
600 0 : ret = -EBUSY;
601 0 : goto done;
602 : }
603 :
604 : re_probe:
605 17 : dev->driver = drv;
606 :
607 : /* If using pinctrl, bind pins now before probing */
608 17 : ret = pinctrl_bind_pins(dev);
609 : if (ret)
610 : goto pinctrl_bind_failed;
611 :
612 17 : if (dev->bus->dma_configure) {
613 17 : ret = dev->bus->dma_configure(dev);
614 17 : if (ret)
615 : goto pinctrl_bind_failed;
616 : }
617 :
618 17 : ret = driver_sysfs_add(dev);
619 17 : if (ret) {
620 0 : pr_err("%s: driver_sysfs_add(%s) failed\n",
621 : __func__, dev_name(dev));
622 0 : goto sysfs_failed;
623 : }
624 :
625 17 : if (dev->pm_domain && dev->pm_domain->activate) {
626 0 : ret = dev->pm_domain->activate(dev);
627 0 : if (ret)
628 : goto probe_failed;
629 : }
630 :
631 17 : ret = call_driver_probe(dev, drv);
632 17 : if (ret) {
633 : /*
634 : * If fw_devlink_best_effort is active (denoted by -EAGAIN), the
635 : * device might actually probe properly once some of its missing
636 : * suppliers have probed. So, treat this as if the driver
637 : * returned -EPROBE_DEFER.
638 : */
639 0 : if (link_ret == -EAGAIN)
640 0 : ret = -EPROBE_DEFER;
641 :
642 : /*
643 : * Return probe errors as positive values so that the callers
644 : * can distinguish them from other errors.
645 : */
646 0 : ret = -ret;
647 0 : goto probe_failed;
648 : }
649 :
650 17 : ret = device_add_groups(dev, drv->dev_groups);
651 17 : if (ret) {
652 0 : dev_err(dev, "device_add_groups() failed\n");
653 0 : goto dev_groups_failed;
654 : }
655 :
656 17 : if (dev_has_sync_state(dev)) {
657 0 : ret = device_create_file(dev, &dev_attr_state_synced);
658 0 : if (ret) {
659 0 : dev_err(dev, "state_synced sysfs add failed\n");
660 0 : goto dev_sysfs_state_synced_failed;
661 : }
662 : }
663 :
664 : if (test_remove) {
665 : test_remove = false;
666 :
667 : device_remove(dev);
668 : driver_sysfs_remove(dev);
669 : device_unbind_cleanup(dev);
670 :
671 : goto re_probe;
672 : }
673 :
674 17 : pinctrl_init_done(dev);
675 :
676 17 : if (dev->pm_domain && dev->pm_domain->sync)
677 0 : dev->pm_domain->sync(dev);
678 :
679 17 : driver_bound(dev);
680 : pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
681 : drv->bus->name, __func__, dev_name(dev), drv->name);
682 17 : goto done;
683 :
684 : dev_sysfs_state_synced_failed:
685 : dev_groups_failed:
686 0 : device_remove(dev);
687 : probe_failed:
688 0 : driver_sysfs_remove(dev);
689 : sysfs_failed:
690 0 : bus_notify(dev, BUS_NOTIFY_DRIVER_NOT_BOUND);
691 0 : if (dev->bus && dev->bus->dma_cleanup)
692 0 : dev->bus->dma_cleanup(dev);
693 : pinctrl_bind_failed:
694 0 : device_links_no_driver(dev);
695 0 : device_unbind_cleanup(dev);
696 : done:
697 : return ret;
698 : }
699 :
700 : /*
701 : * For initcall_debug, show the driver probe time.
702 : */
703 : static int really_probe_debug(struct device *dev, struct device_driver *drv)
704 : {
705 : ktime_t calltime, rettime;
706 : int ret;
707 :
708 0 : calltime = ktime_get();
709 0 : ret = really_probe(dev, drv);
710 0 : rettime = ktime_get();
711 : pr_debug("probe of %s returned %d after %lld usecs\n",
712 : dev_name(dev), ret, ktime_us_delta(rettime, calltime));
713 : return ret;
714 : }
715 :
716 : /**
717 : * driver_probe_done
718 : * Determine if the probe sequence is finished or not.
719 : *
720 : * Should somehow figure out how to use a semaphore, not an atomic variable...
721 : */
722 0 : int driver_probe_done(void)
723 : {
724 0 : int local_probe_count = atomic_read(&probe_count);
725 :
726 : pr_debug("%s: probe_count = %d\n", __func__, local_probe_count);
727 0 : if (local_probe_count)
728 : return -EBUSY;
729 0 : return 0;
730 : }
731 :
732 : /**
733 : * wait_for_device_probe
734 : * Wait for device probing to be completed.
735 : */
736 2 : void wait_for_device_probe(void)
737 : {
738 : /* wait for the deferred probe workqueue to finish */
739 2 : flush_work(&deferred_probe_work);
740 :
741 : /* wait for the known devices to complete their probing */
742 2 : wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
743 2 : async_synchronize_full();
744 2 : }
745 : EXPORT_SYMBOL_GPL(wait_for_device_probe);
746 :
747 17 : static int __driver_probe_device(struct device_driver *drv, struct device *dev)
748 : {
749 17 : int ret = 0;
750 :
751 34 : if (dev->p->dead || !device_is_registered(dev))
752 : return -ENODEV;
753 17 : if (dev->driver)
754 : return -EBUSY;
755 :
756 17 : dev->can_match = true;
757 : pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
758 : drv->bus->name, __func__, dev_name(dev), drv->name);
759 :
760 17 : pm_runtime_get_suppliers(dev);
761 17 : if (dev->parent)
762 17 : pm_runtime_get_sync(dev->parent);
763 :
764 17 : pm_runtime_barrier(dev);
765 17 : if (initcall_debug)
766 0 : ret = really_probe_debug(dev, drv);
767 : else
768 17 : ret = really_probe(dev, drv);
769 17 : pm_request_idle(dev);
770 :
771 17 : if (dev->parent)
772 17 : pm_runtime_put(dev->parent);
773 :
774 17 : pm_runtime_put_suppliers(dev);
775 17 : return ret;
776 : }
777 :
778 : /**
779 : * driver_probe_device - attempt to bind device & driver together
780 : * @drv: driver to bind a device to
781 : * @dev: device to try to bind to the driver
782 : *
783 : * This function returns -ENODEV if the device is not registered, -EBUSY if it
784 : * already has a driver, 0 if the device is bound successfully and a positive
785 : * (inverted) error code for failures from the ->probe method.
786 : *
787 : * This function must be called with @dev lock held. When called for a
788 : * USB interface, @dev->parent lock must be held as well.
789 : *
790 : * If the device has a parent, runtime-resume the parent before driver probing.
791 : */
792 17 : static int driver_probe_device(struct device_driver *drv, struct device *dev)
793 : {
794 17 : int trigger_count = atomic_read(&deferred_trigger_count);
795 : int ret;
796 :
797 17 : atomic_inc(&probe_count);
798 17 : ret = __driver_probe_device(drv, dev);
799 17 : if (ret == -EPROBE_DEFER || ret == EPROBE_DEFER) {
800 0 : driver_deferred_probe_add(dev);
801 :
802 : /*
803 : * Did a trigger occur while probing? Need to re-trigger if yes
804 : */
805 0 : if (trigger_count != atomic_read(&deferred_trigger_count) &&
806 0 : !defer_all_probes)
807 0 : driver_deferred_probe_trigger();
808 : }
809 17 : atomic_dec(&probe_count);
810 17 : wake_up_all(&probe_waitqueue);
811 17 : return ret;
812 : }
813 :
814 : static inline bool cmdline_requested_async_probing(const char *drv_name)
815 : {
816 : bool async_drv;
817 :
818 35 : async_drv = parse_option_str(async_probe_drv_names, drv_name);
819 :
820 35 : return (async_probe_default != async_drv);
821 : }
822 :
823 : /* The option format is "driver_async_probe=drv_name1,drv_name2,..." */
824 0 : static int __init save_async_options(char *buf)
825 : {
826 0 : if (strlen(buf) >= ASYNC_DRV_NAMES_MAX_LEN)
827 0 : pr_warn("Too long list of driver names for 'driver_async_probe'!\n");
828 :
829 0 : strscpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN);
830 0 : async_probe_default = parse_option_str(async_probe_drv_names, "*");
831 :
832 0 : return 1;
833 : }
834 : __setup("driver_async_probe=", save_async_options);
835 :
836 35 : static bool driver_allows_async_probing(struct device_driver *drv)
837 : {
838 35 : switch (drv->probe_type) {
839 : case PROBE_PREFER_ASYNCHRONOUS:
840 : return true;
841 :
842 : case PROBE_FORCE_SYNCHRONOUS:
843 : return false;
844 :
845 : default:
846 70 : if (cmdline_requested_async_probing(drv->name))
847 : return true;
848 :
849 35 : if (module_requested_async_probing(drv->owner))
850 : return true;
851 :
852 : return false;
853 : }
854 : }
855 :
856 : struct device_attach_data {
857 : struct device *dev;
858 :
859 : /*
860 : * Indicates whether we are considering asynchronous probing or
861 : * not. Only initial binding after device or driver registration
862 : * (including deferral processing) may be done asynchronously, the
863 : * rest is always synchronous, as we expect it is being done by
864 : * request from userspace.
865 : */
866 : bool check_async;
867 :
868 : /*
869 : * Indicates if we are binding synchronous or asynchronous drivers.
870 : * When asynchronous probing is enabled we'll execute 2 passes
871 : * over drivers: first pass doing synchronous probing and second
872 : * doing asynchronous probing (if synchronous did not succeed -
873 : * most likely because there was no driver requiring synchronous
874 : * probing - and we found asynchronous driver during first pass).
875 : * The 2 passes are done because we can't shoot asynchronous
876 : * probe for given device and driver from bus_for_each_drv() since
877 : * driver pointer is not guaranteed to stay valid once
878 : * bus_for_each_drv() iterates to the next driver on the bus.
879 : */
880 : bool want_async;
881 :
882 : /*
883 : * We'll set have_async to 'true' if, while scanning for matching
884 : * driver, we'll encounter one that requests asynchronous probing.
885 : */
886 : bool have_async;
887 : };
888 :
889 51 : static int __device_attach_driver(struct device_driver *drv, void *_data)
890 : {
891 51 : struct device_attach_data *data = _data;
892 51 : struct device *dev = data->dev;
893 : bool async_allowed;
894 : int ret;
895 :
896 51 : ret = driver_match_device(drv, dev);
897 51 : if (ret == 0) {
898 : /* no match */
899 : return 0;
900 17 : } else if (ret == -EPROBE_DEFER) {
901 : dev_dbg(dev, "Device match requests probe deferral\n");
902 0 : dev->can_match = true;
903 0 : driver_deferred_probe_add(dev);
904 : /*
905 : * Device can't match with a driver right now, so don't attempt
906 : * to match or bind with other drivers on the bus.
907 : */
908 0 : return ret;
909 17 : } else if (ret < 0) {
910 : dev_dbg(dev, "Bus failed to match device: %d\n", ret);
911 : return ret;
912 : } /* ret > 0 means positive match */
913 :
914 17 : async_allowed = driver_allows_async_probing(drv);
915 :
916 17 : if (async_allowed)
917 0 : data->have_async = true;
918 :
919 17 : if (data->check_async && async_allowed != data->want_async)
920 : return 0;
921 :
922 : /*
923 : * Ignore errors returned by ->probe so that the next driver can try
924 : * its luck.
925 : */
926 17 : ret = driver_probe_device(drv, dev);
927 17 : if (ret < 0)
928 : return ret;
929 17 : return ret == 0;
930 : }
931 :
932 0 : static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
933 : {
934 0 : struct device *dev = _dev;
935 0 : struct device_attach_data data = {
936 : .dev = dev,
937 : .check_async = true,
938 : .want_async = true,
939 : };
940 :
941 0 : device_lock(dev);
942 :
943 : /*
944 : * Check if device has already been removed or claimed. This may
945 : * happen with driver loading, device discovery/registration,
946 : * and deferred probe processing happens all at once with
947 : * multiple threads.
948 : */
949 0 : if (dev->p->dead || dev->driver)
950 : goto out_unlock;
951 :
952 0 : if (dev->parent)
953 0 : pm_runtime_get_sync(dev->parent);
954 :
955 0 : bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver);
956 : dev_dbg(dev, "async probe completed\n");
957 :
958 0 : pm_request_idle(dev);
959 :
960 0 : if (dev->parent)
961 0 : pm_runtime_put(dev->parent);
962 : out_unlock:
963 0 : device_unlock(dev);
964 :
965 0 : put_device(dev);
966 0 : }
967 :
968 21 : static int __device_attach(struct device *dev, bool allow_async)
969 : {
970 21 : int ret = 0;
971 21 : bool async = false;
972 :
973 21 : device_lock(dev);
974 21 : if (dev->p->dead) {
975 : goto out_unlock;
976 21 : } else if (dev->driver) {
977 0 : if (device_is_bound(dev)) {
978 : ret = 1;
979 : goto out_unlock;
980 : }
981 0 : ret = device_bind_driver(dev);
982 0 : if (ret == 0)
983 : ret = 1;
984 : else {
985 0 : dev->driver = NULL;
986 0 : ret = 0;
987 : }
988 : } else {
989 21 : struct device_attach_data data = {
990 : .dev = dev,
991 : .check_async = allow_async,
992 : .want_async = false,
993 : };
994 :
995 21 : if (dev->parent)
996 17 : pm_runtime_get_sync(dev->parent);
997 :
998 21 : ret = bus_for_each_drv(dev->bus, NULL, &data,
999 : __device_attach_driver);
1000 21 : if (!ret && allow_async && data.have_async) {
1001 : /*
1002 : * If we could not find appropriate driver
1003 : * synchronously and we are allowed to do
1004 : * async probes and there are drivers that
1005 : * want to probe asynchronously, we'll
1006 : * try them.
1007 : */
1008 : dev_dbg(dev, "scheduling asynchronous probe\n");
1009 0 : get_device(dev);
1010 0 : async = true;
1011 : } else {
1012 : pm_request_idle(dev);
1013 : }
1014 :
1015 21 : if (dev->parent)
1016 17 : pm_runtime_put(dev->parent);
1017 : }
1018 : out_unlock:
1019 21 : device_unlock(dev);
1020 21 : if (async)
1021 : async_schedule_dev(__device_attach_async_helper, dev);
1022 21 : return ret;
1023 : }
1024 :
1025 : /**
1026 : * device_attach - try to attach device to a driver.
1027 : * @dev: device.
1028 : *
1029 : * Walk the list of drivers that the bus has and call
1030 : * driver_probe_device() for each pair. If a compatible
1031 : * pair is found, break out and return.
1032 : *
1033 : * Returns 1 if the device was bound to a driver;
1034 : * 0 if no matching driver was found;
1035 : * -ENODEV if the device is not registered.
1036 : *
1037 : * When called for a USB interface, @dev->parent lock must be held.
1038 : */
1039 0 : int device_attach(struct device *dev)
1040 : {
1041 0 : return __device_attach(dev, false);
1042 : }
1043 : EXPORT_SYMBOL_GPL(device_attach);
1044 :
1045 21 : void device_initial_probe(struct device *dev)
1046 : {
1047 21 : __device_attach(dev, true);
1048 21 : }
1049 :
1050 : /*
1051 : * __device_driver_lock - acquire locks needed to manipulate dev->drv
1052 : * @dev: Device we will update driver info for
1053 : * @parent: Parent device. Needed if the bus requires parent lock
1054 : *
1055 : * This function will take the required locks for manipulating dev->drv.
1056 : * Normally this will just be the @dev lock, but when called for a USB
1057 : * interface, @parent lock will be held as well.
1058 : */
1059 17 : static void __device_driver_lock(struct device *dev, struct device *parent)
1060 : {
1061 17 : if (parent && dev->bus->need_parent_lock)
1062 : device_lock(parent);
1063 17 : device_lock(dev);
1064 17 : }
1065 :
1066 : /*
1067 : * __device_driver_unlock - release locks needed to manipulate dev->drv
1068 : * @dev: Device we will update driver info for
1069 : * @parent: Parent device. Needed if the bus requires parent lock
1070 : *
1071 : * This function will release the required locks for manipulating dev->drv.
1072 : * Normally this will just be the @dev lock, but when called for a
1073 : * USB interface, @parent lock will be released as well.
1074 : */
1075 17 : static void __device_driver_unlock(struct device *dev, struct device *parent)
1076 : {
1077 17 : device_unlock(dev);
1078 17 : if (parent && dev->bus->need_parent_lock)
1079 : device_unlock(parent);
1080 17 : }
1081 :
1082 : /**
1083 : * device_driver_attach - attach a specific driver to a specific device
1084 : * @drv: Driver to attach
1085 : * @dev: Device to attach it to
1086 : *
1087 : * Manually attach driver to a device. Will acquire both @dev lock and
1088 : * @dev->parent lock if needed. Returns 0 on success, -ERR on failure.
1089 : */
1090 0 : int device_driver_attach(struct device_driver *drv, struct device *dev)
1091 : {
1092 : int ret;
1093 :
1094 0 : __device_driver_lock(dev, dev->parent);
1095 0 : ret = __driver_probe_device(drv, dev);
1096 0 : __device_driver_unlock(dev, dev->parent);
1097 :
1098 : /* also return probe errors as normal negative errnos */
1099 0 : if (ret > 0)
1100 0 : ret = -ret;
1101 0 : if (ret == -EPROBE_DEFER)
1102 : return -EAGAIN;
1103 0 : return ret;
1104 : }
1105 : EXPORT_SYMBOL_GPL(device_driver_attach);
1106 :
1107 0 : static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie)
1108 : {
1109 0 : struct device *dev = _dev;
1110 : struct device_driver *drv;
1111 : int ret;
1112 :
1113 0 : __device_driver_lock(dev, dev->parent);
1114 0 : drv = dev->p->async_driver;
1115 0 : dev->p->async_driver = NULL;
1116 0 : ret = driver_probe_device(drv, dev);
1117 0 : __device_driver_unlock(dev, dev->parent);
1118 :
1119 : dev_dbg(dev, "driver %s async attach completed: %d\n", drv->name, ret);
1120 :
1121 0 : put_device(dev);
1122 0 : }
1123 :
1124 0 : static int __driver_attach(struct device *dev, void *data)
1125 : {
1126 0 : struct device_driver *drv = data;
1127 0 : bool async = false;
1128 : int ret;
1129 :
1130 : /*
1131 : * Lock device and try to bind to it. We drop the error
1132 : * here and always return 0, because we need to keep trying
1133 : * to bind to devices and some drivers will return an error
1134 : * simply if it didn't support the device.
1135 : *
1136 : * driver_probe_device() will spit a warning if there
1137 : * is an error.
1138 : */
1139 :
1140 0 : ret = driver_match_device(drv, dev);
1141 0 : if (ret == 0) {
1142 : /* no match */
1143 : return 0;
1144 0 : } else if (ret == -EPROBE_DEFER) {
1145 : dev_dbg(dev, "Device match requests probe deferral\n");
1146 0 : dev->can_match = true;
1147 0 : driver_deferred_probe_add(dev);
1148 : /*
1149 : * Driver could not match with device, but may match with
1150 : * another device on the bus.
1151 : */
1152 0 : return 0;
1153 0 : } else if (ret < 0) {
1154 : dev_dbg(dev, "Bus failed to match device: %d\n", ret);
1155 : /*
1156 : * Driver could not match with device, but may match with
1157 : * another device on the bus.
1158 : */
1159 : return 0;
1160 : } /* ret > 0 means positive match */
1161 :
1162 0 : if (driver_allows_async_probing(drv)) {
1163 : /*
1164 : * Instead of probing the device synchronously we will
1165 : * probe it asynchronously to allow for more parallelism.
1166 : *
1167 : * We only take the device lock here in order to guarantee
1168 : * that the dev->driver and async_driver fields are protected
1169 : */
1170 : dev_dbg(dev, "probing driver %s asynchronously\n", drv->name);
1171 0 : device_lock(dev);
1172 0 : if (!dev->driver && !dev->p->async_driver) {
1173 0 : get_device(dev);
1174 0 : dev->p->async_driver = drv;
1175 0 : async = true;
1176 : }
1177 0 : device_unlock(dev);
1178 0 : if (async)
1179 : async_schedule_dev(__driver_attach_async_helper, dev);
1180 : return 0;
1181 : }
1182 :
1183 0 : __device_driver_lock(dev, dev->parent);
1184 0 : driver_probe_device(drv, dev);
1185 0 : __device_driver_unlock(dev, dev->parent);
1186 :
1187 0 : return 0;
1188 : }
1189 :
1190 : /**
1191 : * driver_attach - try to bind driver to devices.
1192 : * @drv: driver.
1193 : *
1194 : * Walk the list of devices that the bus has on it and try to
1195 : * match the driver with each one. If driver_probe_device()
1196 : * returns 0 and the @dev->driver is set, we've found a
1197 : * compatible pair.
1198 : */
1199 35 : int driver_attach(struct device_driver *drv)
1200 : {
1201 35 : return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
1202 : }
1203 : EXPORT_SYMBOL_GPL(driver_attach);
1204 :
1205 : /*
1206 : * __device_release_driver() must be called with @dev lock held.
1207 : * When called for a USB interface, @dev->parent lock must be held as well.
1208 : */
1209 17 : static void __device_release_driver(struct device *dev, struct device *parent)
1210 : {
1211 : struct device_driver *drv;
1212 :
1213 17 : drv = dev->driver;
1214 17 : if (drv) {
1215 : pm_runtime_get_sync(dev);
1216 :
1217 17 : while (device_links_busy(dev)) {
1218 0 : __device_driver_unlock(dev, parent);
1219 :
1220 0 : device_links_unbind_consumers(dev);
1221 :
1222 0 : __device_driver_lock(dev, parent);
1223 : /*
1224 : * A concurrent invocation of the same function might
1225 : * have released the driver successfully while this one
1226 : * was waiting, so check for that.
1227 : */
1228 0 : if (dev->driver != drv) {
1229 : pm_runtime_put(dev);
1230 : return;
1231 : }
1232 : }
1233 :
1234 17 : driver_sysfs_remove(dev);
1235 :
1236 17 : bus_notify(dev, BUS_NOTIFY_UNBIND_DRIVER);
1237 :
1238 17 : pm_runtime_put_sync(dev);
1239 :
1240 17 : device_remove(dev);
1241 :
1242 17 : if (dev->bus && dev->bus->dma_cleanup)
1243 17 : dev->bus->dma_cleanup(dev);
1244 :
1245 17 : device_links_driver_cleanup(dev);
1246 17 : device_unbind_cleanup(dev);
1247 :
1248 17 : klist_remove(&dev->p->knode_driver);
1249 17 : device_pm_check_callbacks(dev);
1250 :
1251 17 : bus_notify(dev, BUS_NOTIFY_UNBOUND_DRIVER);
1252 17 : kobject_uevent(&dev->kobj, KOBJ_UNBIND);
1253 : }
1254 : }
1255 :
1256 17 : void device_release_driver_internal(struct device *dev,
1257 : struct device_driver *drv,
1258 : struct device *parent)
1259 : {
1260 17 : __device_driver_lock(dev, parent);
1261 :
1262 17 : if (!drv || drv == dev->driver)
1263 17 : __device_release_driver(dev, parent);
1264 :
1265 17 : __device_driver_unlock(dev, parent);
1266 17 : }
1267 :
1268 : /**
1269 : * device_release_driver - manually detach device from driver.
1270 : * @dev: device.
1271 : *
1272 : * Manually detach device from driver.
1273 : * When called for a USB interface, @dev->parent lock must be held.
1274 : *
1275 : * If this function is to be called with @dev->parent lock held, ensure that
1276 : * the device's consumers are unbound in advance or that their locks can be
1277 : * acquired under the @dev->parent lock.
1278 : */
1279 17 : void device_release_driver(struct device *dev)
1280 : {
1281 : /*
1282 : * If anyone calls device_release_driver() recursively from
1283 : * within their ->remove callback for the same device, they
1284 : * will deadlock right here.
1285 : */
1286 17 : device_release_driver_internal(dev, NULL, NULL);
1287 17 : }
1288 : EXPORT_SYMBOL_GPL(device_release_driver);
1289 :
1290 : /**
1291 : * device_driver_detach - detach driver from a specific device
1292 : * @dev: device to detach driver from
1293 : *
1294 : * Detach driver from device. Will acquire both @dev lock and @dev->parent
1295 : * lock if needed.
1296 : */
1297 0 : void device_driver_detach(struct device *dev)
1298 : {
1299 0 : device_release_driver_internal(dev, NULL, dev->parent);
1300 0 : }
1301 :
1302 : /**
1303 : * driver_detach - detach driver from all devices it controls.
1304 : * @drv: driver.
1305 : */
1306 18 : void driver_detach(struct device_driver *drv)
1307 : {
1308 : struct device_private *dev_prv;
1309 : struct device *dev;
1310 :
1311 18 : if (driver_allows_async_probing(drv))
1312 0 : async_synchronize_full();
1313 :
1314 : for (;;) {
1315 36 : spin_lock(&drv->p->klist_devices.k_lock);
1316 36 : if (list_empty(&drv->p->klist_devices.k_list)) {
1317 36 : spin_unlock(&drv->p->klist_devices.k_lock);
1318 : break;
1319 : }
1320 0 : dev_prv = list_last_entry(&drv->p->klist_devices.k_list,
1321 : struct device_private,
1322 : knode_driver.n_node);
1323 0 : dev = dev_prv->device;
1324 0 : get_device(dev);
1325 0 : spin_unlock(&drv->p->klist_devices.k_lock);
1326 0 : device_release_driver_internal(dev, drv, dev->parent);
1327 0 : put_device(dev);
1328 : }
1329 18 : }
|
