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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * drivers/base/core.c - core driver model code (device registration, etc)
4 *
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
7 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
8 * Copyright (c) 2006 Novell, Inc.
9 */
10
11#include <linux/acpi.h>
12#include <linux/cpufreq.h>
13#include <linux/device.h>
14#include <linux/err.h>
15#include <linux/fwnode.h>
16#include <linux/init.h>
17#include <linux/kstrtox.h>
18#include <linux/module.h>
19#include <linux/slab.h>
20#include <linux/string.h>
21#include <linux/kdev_t.h>
22#include <linux/notifier.h>
23#include <linux/of.h>
24#include <linux/of_device.h>
25#include <linux/blkdev.h>
26#include <linux/mutex.h>
27#include <linux/pm_runtime.h>
28#include <linux/netdevice.h>
29#include <linux/sched/signal.h>
30#include <linux/sched/mm.h>
31#include <linux/swiotlb.h>
32#include <linux/sysfs.h>
33#include <linux/dma-map-ops.h> /* for dma_default_coherent */
34
35#include "base.h"
36#include "physical_location.h"
37#include "power/power.h"
38
39#ifdef CONFIG_SYSFS_DEPRECATED
40#ifdef CONFIG_SYSFS_DEPRECATED_V2
41long sysfs_deprecated = 1;
42#else
43long sysfs_deprecated = 0;
44#endif
45static int __init sysfs_deprecated_setup(char *arg)
46{
47 return kstrtol(arg, 10, &sysfs_deprecated);
48}
49early_param("sysfs.deprecated", sysfs_deprecated_setup);
50#endif
51
52/* Device links support. */
53static LIST_HEAD(deferred_sync);
54static unsigned int defer_sync_state_count = 1;
55static DEFINE_MUTEX(fwnode_link_lock);
56static bool fw_devlink_is_permissive(void);
57static bool fw_devlink_drv_reg_done;
58static bool fw_devlink_best_effort;
59
60/**
61 * fwnode_link_add - Create a link between two fwnode_handles.
62 * @con: Consumer end of the link.
63 * @sup: Supplier end of the link.
64 *
65 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
66 * represents the detail that the firmware lists @sup fwnode as supplying a
67 * resource to @con.
68 *
69 * The driver core will use the fwnode link to create a device link between the
70 * two device objects corresponding to @con and @sup when they are created. The
71 * driver core will automatically delete the fwnode link between @con and @sup
72 * after doing that.
73 *
74 * Attempts to create duplicate links between the same pair of fwnode handles
75 * are ignored and there is no reference counting.
76 */
77int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
78{
79 struct fwnode_link *link;
80 int ret = 0;
81
82 mutex_lock(&fwnode_link_lock);
83
84 list_for_each_entry(link, &sup->consumers, s_hook)
85 if (link->consumer == con)
86 goto out;
87
88 link = kzalloc(sizeof(*link), GFP_KERNEL);
89 if (!link) {
90 ret = -ENOMEM;
91 goto out;
92 }
93
94 link->supplier = sup;
95 INIT_LIST_HEAD(&link->s_hook);
96 link->consumer = con;
97 INIT_LIST_HEAD(&link->c_hook);
98
99 list_add(&link->s_hook, &sup->consumers);
100 list_add(&link->c_hook, &con->suppliers);
101 pr_debug("%pfwP Linked as a fwnode consumer to %pfwP\n",
102 con, sup);
103out:
104 mutex_unlock(&fwnode_link_lock);
105
106 return ret;
107}
108
109/**
110 * __fwnode_link_del - Delete a link between two fwnode_handles.
111 * @link: the fwnode_link to be deleted
112 *
113 * The fwnode_link_lock needs to be held when this function is called.
114 */
115static void __fwnode_link_del(struct fwnode_link *link)
116{
117 pr_debug("%pfwP Dropping the fwnode link to %pfwP\n",
118 link->consumer, link->supplier);
119 list_del(&link->s_hook);
120 list_del(&link->c_hook);
121 kfree(link);
122}
123
124/**
125 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
126 * @fwnode: fwnode whose supplier links need to be deleted
127 *
128 * Deletes all supplier links connecting directly to @fwnode.
129 */
130static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
131{
132 struct fwnode_link *link, *tmp;
133
134 mutex_lock(&fwnode_link_lock);
135 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook)
136 __fwnode_link_del(link);
137 mutex_unlock(&fwnode_link_lock);
138}
139
140/**
141 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
142 * @fwnode: fwnode whose consumer links need to be deleted
143 *
144 * Deletes all consumer links connecting directly to @fwnode.
145 */
146static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
147{
148 struct fwnode_link *link, *tmp;
149
150 mutex_lock(&fwnode_link_lock);
151 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook)
152 __fwnode_link_del(link);
153 mutex_unlock(&fwnode_link_lock);
154}
155
156/**
157 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
158 * @fwnode: fwnode whose links needs to be deleted
159 *
160 * Deletes all links connecting directly to a fwnode.
161 */
162void fwnode_links_purge(struct fwnode_handle *fwnode)
163{
164 fwnode_links_purge_suppliers(fwnode);
165 fwnode_links_purge_consumers(fwnode);
166}
167
168void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
169{
170 struct fwnode_handle *child;
171
172 /* Don't purge consumer links of an added child */
173 if (fwnode->dev)
174 return;
175
176 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
177 fwnode_links_purge_consumers(fwnode);
178
179 fwnode_for_each_available_child_node(fwnode, child)
180 fw_devlink_purge_absent_suppliers(child);
181}
182EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
183
184#ifdef CONFIG_SRCU
185static DEFINE_MUTEX(device_links_lock);
186DEFINE_STATIC_SRCU(device_links_srcu);
187
188static inline void device_links_write_lock(void)
189{
190 mutex_lock(&device_links_lock);
191}
192
193static inline void device_links_write_unlock(void)
194{
195 mutex_unlock(&device_links_lock);
196}
197
198int device_links_read_lock(void) __acquires(&device_links_srcu)
199{
200 return srcu_read_lock(&device_links_srcu);
201}
202
203void device_links_read_unlock(int idx) __releases(&device_links_srcu)
204{
205 srcu_read_unlock(&device_links_srcu, idx);
206}
207
208int device_links_read_lock_held(void)
209{
210 return srcu_read_lock_held(&device_links_srcu);
211}
212
213static void device_link_synchronize_removal(void)
214{
215 synchronize_srcu(&device_links_srcu);
216}
217
218static void device_link_remove_from_lists(struct device_link *link)
219{
220 list_del_rcu(&link->s_node);
221 list_del_rcu(&link->c_node);
222}
223#else /* !CONFIG_SRCU */
224static DECLARE_RWSEM(device_links_lock);
225
226static inline void device_links_write_lock(void)
227{
228 down_write(&device_links_lock);
229}
230
231static inline void device_links_write_unlock(void)
232{
233 up_write(&device_links_lock);
234}
235
236int device_links_read_lock(void)
237{
238 down_read(&device_links_lock);
239 return 0;
240}
241
242void device_links_read_unlock(int not_used)
243{
244 up_read(&device_links_lock);
245}
246
247#ifdef CONFIG_DEBUG_LOCK_ALLOC
248int device_links_read_lock_held(void)
249{
250 return lockdep_is_held(&device_links_lock);
251}
252#endif
253
254static inline void device_link_synchronize_removal(void)
255{
256}
257
258static void device_link_remove_from_lists(struct device_link *link)
259{
260 list_del(&link->s_node);
261 list_del(&link->c_node);
262}
263#endif /* !CONFIG_SRCU */
264
265static bool device_is_ancestor(struct device *dev, struct device *target)
266{
267 while (target->parent) {
268 target = target->parent;
269 if (dev == target)
270 return true;
271 }
272 return false;
273}
274
275/**
276 * device_is_dependent - Check if one device depends on another one
277 * @dev: Device to check dependencies for.
278 * @target: Device to check against.
279 *
280 * Check if @target depends on @dev or any device dependent on it (its child or
281 * its consumer etc). Return 1 if that is the case or 0 otherwise.
282 */
283int device_is_dependent(struct device *dev, void *target)
284{
285 struct device_link *link;
286 int ret;
287
288 /*
289 * The "ancestors" check is needed to catch the case when the target
290 * device has not been completely initialized yet and it is still
291 * missing from the list of children of its parent device.
292 */
293 if (dev == target || device_is_ancestor(dev, target))
294 return 1;
295
296 ret = device_for_each_child(dev, target, device_is_dependent);
297 if (ret)
298 return ret;
299
300 list_for_each_entry(link, &dev->links.consumers, s_node) {
301 if ((link->flags & ~DL_FLAG_INFERRED) ==
302 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
303 continue;
304
305 if (link->consumer == target)
306 return 1;
307
308 ret = device_is_dependent(link->consumer, target);
309 if (ret)
310 break;
311 }
312 return ret;
313}
314
315static void device_link_init_status(struct device_link *link,
316 struct device *consumer,
317 struct device *supplier)
318{
319 switch (supplier->links.status) {
320 case DL_DEV_PROBING:
321 switch (consumer->links.status) {
322 case DL_DEV_PROBING:
323 /*
324 * A consumer driver can create a link to a supplier
325 * that has not completed its probing yet as long as it
326 * knows that the supplier is already functional (for
327 * example, it has just acquired some resources from the
328 * supplier).
329 */
330 link->status = DL_STATE_CONSUMER_PROBE;
331 break;
332 default:
333 link->status = DL_STATE_DORMANT;
334 break;
335 }
336 break;
337 case DL_DEV_DRIVER_BOUND:
338 switch (consumer->links.status) {
339 case DL_DEV_PROBING:
340 link->status = DL_STATE_CONSUMER_PROBE;
341 break;
342 case DL_DEV_DRIVER_BOUND:
343 link->status = DL_STATE_ACTIVE;
344 break;
345 default:
346 link->status = DL_STATE_AVAILABLE;
347 break;
348 }
349 break;
350 case DL_DEV_UNBINDING:
351 link->status = DL_STATE_SUPPLIER_UNBIND;
352 break;
353 default:
354 link->status = DL_STATE_DORMANT;
355 break;
356 }
357}
358
359static int device_reorder_to_tail(struct device *dev, void *not_used)
360{
361 struct device_link *link;
362
363 /*
364 * Devices that have not been registered yet will be put to the ends
365 * of the lists during the registration, so skip them here.
366 */
367 if (device_is_registered(dev))
368 devices_kset_move_last(dev);
369
370 if (device_pm_initialized(dev))
371 device_pm_move_last(dev);
372
373 device_for_each_child(dev, NULL, device_reorder_to_tail);
374 list_for_each_entry(link, &dev->links.consumers, s_node) {
375 if ((link->flags & ~DL_FLAG_INFERRED) ==
376 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
377 continue;
378 device_reorder_to_tail(link->consumer, NULL);
379 }
380
381 return 0;
382}
383
384/**
385 * device_pm_move_to_tail - Move set of devices to the end of device lists
386 * @dev: Device to move
387 *
388 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
389 *
390 * It moves the @dev along with all of its children and all of its consumers
391 * to the ends of the device_kset and dpm_list, recursively.
392 */
393void device_pm_move_to_tail(struct device *dev)
394{
395 int idx;
396
397 idx = device_links_read_lock();
398 device_pm_lock();
399 device_reorder_to_tail(dev, NULL);
400 device_pm_unlock();
401 device_links_read_unlock(idx);
402}
403
404#define to_devlink(dev) container_of((dev), struct device_link, link_dev)
405
406static ssize_t status_show(struct device *dev,
407 struct device_attribute *attr, char *buf)
408{
409 const char *output;
410
411 switch (to_devlink(dev)->status) {
412 case DL_STATE_NONE:
413 output = "not tracked";
414 break;
415 case DL_STATE_DORMANT:
416 output = "dormant";
417 break;
418 case DL_STATE_AVAILABLE:
419 output = "available";
420 break;
421 case DL_STATE_CONSUMER_PROBE:
422 output = "consumer probing";
423 break;
424 case DL_STATE_ACTIVE:
425 output = "active";
426 break;
427 case DL_STATE_SUPPLIER_UNBIND:
428 output = "supplier unbinding";
429 break;
430 default:
431 output = "unknown";
432 break;
433 }
434
435 return sysfs_emit(buf, "%s\n", output);
436}
437static DEVICE_ATTR_RO(status);
438
439static ssize_t auto_remove_on_show(struct device *dev,
440 struct device_attribute *attr, char *buf)
441{
442 struct device_link *link = to_devlink(dev);
443 const char *output;
444
445 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
446 output = "supplier unbind";
447 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
448 output = "consumer unbind";
449 else
450 output = "never";
451
452 return sysfs_emit(buf, "%s\n", output);
453}
454static DEVICE_ATTR_RO(auto_remove_on);
455
456static ssize_t runtime_pm_show(struct device *dev,
457 struct device_attribute *attr, char *buf)
458{
459 struct device_link *link = to_devlink(dev);
460
461 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
462}
463static DEVICE_ATTR_RO(runtime_pm);
464
465static ssize_t sync_state_only_show(struct device *dev,
466 struct device_attribute *attr, char *buf)
467{
468 struct device_link *link = to_devlink(dev);
469
470 return sysfs_emit(buf, "%d\n",
471 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
472}
473static DEVICE_ATTR_RO(sync_state_only);
474
475static struct attribute *devlink_attrs[] = {
476 &dev_attr_status.attr,
477 &dev_attr_auto_remove_on.attr,
478 &dev_attr_runtime_pm.attr,
479 &dev_attr_sync_state_only.attr,
480 NULL,
481};
482ATTRIBUTE_GROUPS(devlink);
483
484static void device_link_release_fn(struct work_struct *work)
485{
486 struct device_link *link = container_of(work, struct device_link, rm_work);
487
488 /* Ensure that all references to the link object have been dropped. */
489 device_link_synchronize_removal();
490
491 pm_runtime_release_supplier(link);
492 /*
493 * If supplier_preactivated is set, the link has been dropped between
494 * the pm_runtime_get_suppliers() and pm_runtime_put_suppliers() calls
495 * in __driver_probe_device(). In that case, drop the supplier's
496 * PM-runtime usage counter to remove the reference taken by
497 * pm_runtime_get_suppliers().
498 */
499 if (link->supplier_preactivated)
500 pm_runtime_put_noidle(link->supplier);
501
502 pm_request_idle(link->supplier);
503
504 put_device(link->consumer);
505 put_device(link->supplier);
506 kfree(link);
507}
508
509static void devlink_dev_release(struct device *dev)
510{
511 struct device_link *link = to_devlink(dev);
512
513 INIT_WORK(&link->rm_work, device_link_release_fn);
514 /*
515 * It may take a while to complete this work because of the SRCU
516 * synchronization in device_link_release_fn() and if the consumer or
517 * supplier devices get deleted when it runs, so put it into the "long"
518 * workqueue.
519 */
520 queue_work(system_long_wq, &link->rm_work);
521}
522
523static struct class devlink_class = {
524 .name = "devlink",
525 .owner = THIS_MODULE,
526 .dev_groups = devlink_groups,
527 .dev_release = devlink_dev_release,
528};
529
530static int devlink_add_symlinks(struct device *dev,
531 struct class_interface *class_intf)
532{
533 int ret;
534 size_t len;
535 struct device_link *link = to_devlink(dev);
536 struct device *sup = link->supplier;
537 struct device *con = link->consumer;
538 char *buf;
539
540 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
541 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
542 len += strlen(":");
543 len += strlen("supplier:") + 1;
544 buf = kzalloc(len, GFP_KERNEL);
545 if (!buf)
546 return -ENOMEM;
547
548 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
549 if (ret)
550 goto out;
551
552 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
553 if (ret)
554 goto err_con;
555
556 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
557 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
558 if (ret)
559 goto err_con_dev;
560
561 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
562 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
563 if (ret)
564 goto err_sup_dev;
565
566 goto out;
567
568err_sup_dev:
569 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
570 sysfs_remove_link(&sup->kobj, buf);
571err_con_dev:
572 sysfs_remove_link(&link->link_dev.kobj, "consumer");
573err_con:
574 sysfs_remove_link(&link->link_dev.kobj, "supplier");
575out:
576 kfree(buf);
577 return ret;
578}
579
580static void devlink_remove_symlinks(struct device *dev,
581 struct class_interface *class_intf)
582{
583 struct device_link *link = to_devlink(dev);
584 size_t len;
585 struct device *sup = link->supplier;
586 struct device *con = link->consumer;
587 char *buf;
588
589 sysfs_remove_link(&link->link_dev.kobj, "consumer");
590 sysfs_remove_link(&link->link_dev.kobj, "supplier");
591
592 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
593 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
594 len += strlen(":");
595 len += strlen("supplier:") + 1;
596 buf = kzalloc(len, GFP_KERNEL);
597 if (!buf) {
598 WARN(1, "Unable to properly free device link symlinks!\n");
599 return;
600 }
601
602 if (device_is_registered(con)) {
603 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
604 sysfs_remove_link(&con->kobj, buf);
605 }
606 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
607 sysfs_remove_link(&sup->kobj, buf);
608 kfree(buf);
609}
610
611static struct class_interface devlink_class_intf = {
612 .class = &devlink_class,
613 .add_dev = devlink_add_symlinks,
614 .remove_dev = devlink_remove_symlinks,
615};
616
617static int __init devlink_class_init(void)
618{
619 int ret;
620
621 ret = class_register(&devlink_class);
622 if (ret)
623 return ret;
624
625 ret = class_interface_register(&devlink_class_intf);
626 if (ret)
627 class_unregister(&devlink_class);
628
629 return ret;
630}
631postcore_initcall(devlink_class_init);
632
633#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
634 DL_FLAG_AUTOREMOVE_SUPPLIER | \
635 DL_FLAG_AUTOPROBE_CONSUMER | \
636 DL_FLAG_SYNC_STATE_ONLY | \
637 DL_FLAG_INFERRED)
638
639#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
640 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
641
642/**
643 * device_link_add - Create a link between two devices.
644 * @consumer: Consumer end of the link.
645 * @supplier: Supplier end of the link.
646 * @flags: Link flags.
647 *
648 * The caller is responsible for the proper synchronization of the link creation
649 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
650 * runtime PM framework to take the link into account. Second, if the
651 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
652 * be forced into the active meta state and reference-counted upon the creation
653 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
654 * ignored.
655 *
656 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
657 * expected to release the link returned by it directly with the help of either
658 * device_link_del() or device_link_remove().
659 *
660 * If that flag is not set, however, the caller of this function is handing the
661 * management of the link over to the driver core entirely and its return value
662 * can only be used to check whether or not the link is present. In that case,
663 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
664 * flags can be used to indicate to the driver core when the link can be safely
665 * deleted. Namely, setting one of them in @flags indicates to the driver core
666 * that the link is not going to be used (by the given caller of this function)
667 * after unbinding the consumer or supplier driver, respectively, from its
668 * device, so the link can be deleted at that point. If none of them is set,
669 * the link will be maintained until one of the devices pointed to by it (either
670 * the consumer or the supplier) is unregistered.
671 *
672 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
673 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
674 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
675 * be used to request the driver core to automatically probe for a consumer
676 * driver after successfully binding a driver to the supplier device.
677 *
678 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
679 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
680 * the same time is invalid and will cause NULL to be returned upfront.
681 * However, if a device link between the given @consumer and @supplier pair
682 * exists already when this function is called for them, the existing link will
683 * be returned regardless of its current type and status (the link's flags may
684 * be modified then). The caller of this function is then expected to treat
685 * the link as though it has just been created, so (in particular) if
686 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
687 * explicitly when not needed any more (as stated above).
688 *
689 * A side effect of the link creation is re-ordering of dpm_list and the
690 * devices_kset list by moving the consumer device and all devices depending
691 * on it to the ends of these lists (that does not happen to devices that have
692 * not been registered when this function is called).
693 *
694 * The supplier device is required to be registered when this function is called
695 * and NULL will be returned if that is not the case. The consumer device need
696 * not be registered, however.
697 */
698struct device_link *device_link_add(struct device *consumer,
699 struct device *supplier, u32 flags)
700{
701 struct device_link *link;
702
703 if (!consumer || !supplier || consumer == supplier ||
704 flags & ~DL_ADD_VALID_FLAGS ||
705 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
706 (flags & DL_FLAG_SYNC_STATE_ONLY &&
707 (flags & ~DL_FLAG_INFERRED) != DL_FLAG_SYNC_STATE_ONLY) ||
708 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
709 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
710 DL_FLAG_AUTOREMOVE_SUPPLIER)))
711 return NULL;
712
713 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
714 if (pm_runtime_get_sync(supplier) < 0) {
715 pm_runtime_put_noidle(supplier);
716 return NULL;
717 }
718 }
719
720 if (!(flags & DL_FLAG_STATELESS))
721 flags |= DL_FLAG_MANAGED;
722
723 device_links_write_lock();
724 device_pm_lock();
725
726 /*
727 * If the supplier has not been fully registered yet or there is a
728 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
729 * the supplier already in the graph, return NULL. If the link is a
730 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
731 * because it only affects sync_state() callbacks.
732 */
733 if (!device_pm_initialized(supplier)
734 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
735 device_is_dependent(consumer, supplier))) {
736 link = NULL;
737 goto out;
738 }
739
740 /*
741 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
742 * So, only create it if the consumer hasn't probed yet.
743 */
744 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
745 consumer->links.status != DL_DEV_NO_DRIVER &&
746 consumer->links.status != DL_DEV_PROBING) {
747 link = NULL;
748 goto out;
749 }
750
751 /*
752 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
753 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
754 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
755 */
756 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
757 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
758
759 list_for_each_entry(link, &supplier->links.consumers, s_node) {
760 if (link->consumer != consumer)
761 continue;
762
763 if (link->flags & DL_FLAG_INFERRED &&
764 !(flags & DL_FLAG_INFERRED))
765 link->flags &= ~DL_FLAG_INFERRED;
766
767 if (flags & DL_FLAG_PM_RUNTIME) {
768 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
769 pm_runtime_new_link(consumer);
770 link->flags |= DL_FLAG_PM_RUNTIME;
771 }
772 if (flags & DL_FLAG_RPM_ACTIVE)
773 refcount_inc(&link->rpm_active);
774 }
775
776 if (flags & DL_FLAG_STATELESS) {
777 kref_get(&link->kref);
778 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
779 !(link->flags & DL_FLAG_STATELESS)) {
780 link->flags |= DL_FLAG_STATELESS;
781 goto reorder;
782 } else {
783 link->flags |= DL_FLAG_STATELESS;
784 goto out;
785 }
786 }
787
788 /*
789 * If the life time of the link following from the new flags is
790 * longer than indicated by the flags of the existing link,
791 * update the existing link to stay around longer.
792 */
793 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
794 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
795 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
796 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
797 }
798 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
799 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
800 DL_FLAG_AUTOREMOVE_SUPPLIER);
801 }
802 if (!(link->flags & DL_FLAG_MANAGED)) {
803 kref_get(&link->kref);
804 link->flags |= DL_FLAG_MANAGED;
805 device_link_init_status(link, consumer, supplier);
806 }
807 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
808 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
809 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
810 goto reorder;
811 }
812
813 goto out;
814 }
815
816 link = kzalloc(sizeof(*link), GFP_KERNEL);
817 if (!link)
818 goto out;
819
820 refcount_set(&link->rpm_active, 1);
821
822 get_device(supplier);
823 link->supplier = supplier;
824 INIT_LIST_HEAD(&link->s_node);
825 get_device(consumer);
826 link->consumer = consumer;
827 INIT_LIST_HEAD(&link->c_node);
828 link->flags = flags;
829 kref_init(&link->kref);
830
831 link->link_dev.class = &devlink_class;
832 device_set_pm_not_required(&link->link_dev);
833 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
834 dev_bus_name(supplier), dev_name(supplier),
835 dev_bus_name(consumer), dev_name(consumer));
836 if (device_register(&link->link_dev)) {
837 put_device(&link->link_dev);
838 link = NULL;
839 goto out;
840 }
841
842 if (flags & DL_FLAG_PM_RUNTIME) {
843 if (flags & DL_FLAG_RPM_ACTIVE)
844 refcount_inc(&link->rpm_active);
845
846 pm_runtime_new_link(consumer);
847 }
848
849 /* Determine the initial link state. */
850 if (flags & DL_FLAG_STATELESS)
851 link->status = DL_STATE_NONE;
852 else
853 device_link_init_status(link, consumer, supplier);
854
855 /*
856 * Some callers expect the link creation during consumer driver probe to
857 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
858 */
859 if (link->status == DL_STATE_CONSUMER_PROBE &&
860 flags & DL_FLAG_PM_RUNTIME)
861 pm_runtime_resume(supplier);
862
863 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
864 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
865
866 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
867 dev_dbg(consumer,
868 "Linked as a sync state only consumer to %s\n",
869 dev_name(supplier));
870 goto out;
871 }
872
873reorder:
874 /*
875 * Move the consumer and all of the devices depending on it to the end
876 * of dpm_list and the devices_kset list.
877 *
878 * It is necessary to hold dpm_list locked throughout all that or else
879 * we may end up suspending with a wrong ordering of it.
880 */
881 device_reorder_to_tail(consumer, NULL);
882
883 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
884
885out:
886 device_pm_unlock();
887 device_links_write_unlock();
888
889 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
890 pm_runtime_put(supplier);
891
892 return link;
893}
894EXPORT_SYMBOL_GPL(device_link_add);
895
896static void __device_link_del(struct kref *kref)
897{
898 struct device_link *link = container_of(kref, struct device_link, kref);
899
900 dev_dbg(link->consumer, "Dropping the link to %s\n",
901 dev_name(link->supplier));
902
903 pm_runtime_drop_link(link);
904
905 device_link_remove_from_lists(link);
906 device_unregister(&link->link_dev);
907}
908
909static void device_link_put_kref(struct device_link *link)
910{
911 if (link->flags & DL_FLAG_STATELESS)
912 kref_put(&link->kref, __device_link_del);
913 else if (!device_is_registered(link->consumer))
914 __device_link_del(&link->kref);
915 else
916 WARN(1, "Unable to drop a managed device link reference\n");
917}
918
919/**
920 * device_link_del - Delete a stateless link between two devices.
921 * @link: Device link to delete.
922 *
923 * The caller must ensure proper synchronization of this function with runtime
924 * PM. If the link was added multiple times, it needs to be deleted as often.
925 * Care is required for hotplugged devices: Their links are purged on removal
926 * and calling device_link_del() is then no longer allowed.
927 */
928void device_link_del(struct device_link *link)
929{
930 device_links_write_lock();
931 device_link_put_kref(link);
932 device_links_write_unlock();
933}
934EXPORT_SYMBOL_GPL(device_link_del);
935
936/**
937 * device_link_remove - Delete a stateless link between two devices.
938 * @consumer: Consumer end of the link.
939 * @supplier: Supplier end of the link.
940 *
941 * The caller must ensure proper synchronization of this function with runtime
942 * PM.
943 */
944void device_link_remove(void *consumer, struct device *supplier)
945{
946 struct device_link *link;
947
948 if (WARN_ON(consumer == supplier))
949 return;
950
951 device_links_write_lock();
952
953 list_for_each_entry(link, &supplier->links.consumers, s_node) {
954 if (link->consumer == consumer) {
955 device_link_put_kref(link);
956 break;
957 }
958 }
959
960 device_links_write_unlock();
961}
962EXPORT_SYMBOL_GPL(device_link_remove);
963
964static void device_links_missing_supplier(struct device *dev)
965{
966 struct device_link *link;
967
968 list_for_each_entry(link, &dev->links.suppliers, c_node) {
969 if (link->status != DL_STATE_CONSUMER_PROBE)
970 continue;
971
972 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
973 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
974 } else {
975 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
976 WRITE_ONCE(link->status, DL_STATE_DORMANT);
977 }
978 }
979}
980
981static bool dev_is_best_effort(struct device *dev)
982{
983 return (fw_devlink_best_effort && dev->can_match) ||
984 (dev->fwnode && (dev->fwnode->flags & FWNODE_FLAG_BEST_EFFORT));
985}
986
987/**
988 * device_links_check_suppliers - Check presence of supplier drivers.
989 * @dev: Consumer device.
990 *
991 * Check links from this device to any suppliers. Walk the list of the device's
992 * links to suppliers and see if all of them are available. If not, simply
993 * return -EPROBE_DEFER.
994 *
995 * We need to guarantee that the supplier will not go away after the check has
996 * been positive here. It only can go away in __device_release_driver() and
997 * that function checks the device's links to consumers. This means we need to
998 * mark the link as "consumer probe in progress" to make the supplier removal
999 * wait for us to complete (or bad things may happen).
1000 *
1001 * Links without the DL_FLAG_MANAGED flag set are ignored.
1002 */
1003int device_links_check_suppliers(struct device *dev)
1004{
1005 struct device_link *link;
1006 int ret = 0, fwnode_ret = 0;
1007 struct fwnode_handle *sup_fw;
1008
1009 /*
1010 * Device waiting for supplier to become available is not allowed to
1011 * probe.
1012 */
1013 mutex_lock(&fwnode_link_lock);
1014 if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) &&
1015 !fw_devlink_is_permissive()) {
1016 sup_fw = list_first_entry(&dev->fwnode->suppliers,
1017 struct fwnode_link,
1018 c_hook)->supplier;
1019 if (!dev_is_best_effort(dev)) {
1020 fwnode_ret = -EPROBE_DEFER;
1021 dev_err_probe(dev, -EPROBE_DEFER,
1022 "wait for supplier %pfwP\n", sup_fw);
1023 } else {
1024 fwnode_ret = -EAGAIN;
1025 }
1026 }
1027 mutex_unlock(&fwnode_link_lock);
1028 if (fwnode_ret == -EPROBE_DEFER)
1029 return fwnode_ret;
1030
1031 device_links_write_lock();
1032
1033 list_for_each_entry(link, &dev->links.suppliers, c_node) {
1034 if (!(link->flags & DL_FLAG_MANAGED))
1035 continue;
1036
1037 if (link->status != DL_STATE_AVAILABLE &&
1038 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
1039
1040 if (dev_is_best_effort(dev) &&
1041 link->flags & DL_FLAG_INFERRED &&
1042 !link->supplier->can_match) {
1043 ret = -EAGAIN;
1044 continue;
1045 }
1046
1047 device_links_missing_supplier(dev);
1048 dev_err_probe(dev, -EPROBE_DEFER,
1049 "supplier %s not ready\n",
1050 dev_name(link->supplier));
1051 ret = -EPROBE_DEFER;
1052 break;
1053 }
1054 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1055 }
1056 dev->links.status = DL_DEV_PROBING;
1057
1058 device_links_write_unlock();
1059
1060 return ret ? ret : fwnode_ret;
1061}
1062
1063/**
1064 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1065 * @dev: Device to call sync_state() on
1066 * @list: List head to queue the @dev on
1067 *
1068 * Queues a device for a sync_state() callback when the device links write lock
1069 * isn't held. This allows the sync_state() execution flow to use device links
1070 * APIs. The caller must ensure this function is called with
1071 * device_links_write_lock() held.
1072 *
1073 * This function does a get_device() to make sure the device is not freed while
1074 * on this list.
1075 *
1076 * So the caller must also ensure that device_links_flush_sync_list() is called
1077 * as soon as the caller releases device_links_write_lock(). This is necessary
1078 * to make sure the sync_state() is called in a timely fashion and the
1079 * put_device() is called on this device.
1080 */
1081static void __device_links_queue_sync_state(struct device *dev,
1082 struct list_head *list)
1083{
1084 struct device_link *link;
1085
1086 if (!dev_has_sync_state(dev))
1087 return;
1088 if (dev->state_synced)
1089 return;
1090
1091 list_for_each_entry(link, &dev->links.consumers, s_node) {
1092 if (!(link->flags & DL_FLAG_MANAGED))
1093 continue;
1094 if (link->status != DL_STATE_ACTIVE)
1095 return;
1096 }
1097
1098 /*
1099 * Set the flag here to avoid adding the same device to a list more
1100 * than once. This can happen if new consumers get added to the device
1101 * and probed before the list is flushed.
1102 */
1103 dev->state_synced = true;
1104
1105 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1106 return;
1107
1108 get_device(dev);
1109 list_add_tail(&dev->links.defer_sync, list);
1110}
1111
1112/**
1113 * device_links_flush_sync_list - Call sync_state() on a list of devices
1114 * @list: List of devices to call sync_state() on
1115 * @dont_lock_dev: Device for which lock is already held by the caller
1116 *
1117 * Calls sync_state() on all the devices that have been queued for it. This
1118 * function is used in conjunction with __device_links_queue_sync_state(). The
1119 * @dont_lock_dev parameter is useful when this function is called from a
1120 * context where a device lock is already held.
1121 */
1122static void device_links_flush_sync_list(struct list_head *list,
1123 struct device *dont_lock_dev)
1124{
1125 struct device *dev, *tmp;
1126
1127 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1128 list_del_init(&dev->links.defer_sync);
1129
1130 if (dev != dont_lock_dev)
1131 device_lock(dev);
1132
1133 if (dev->bus->sync_state)
1134 dev->bus->sync_state(dev);
1135 else if (dev->driver && dev->driver->sync_state)
1136 dev->driver->sync_state(dev);
1137
1138 if (dev != dont_lock_dev)
1139 device_unlock(dev);
1140
1141 put_device(dev);
1142 }
1143}
1144
1145void device_links_supplier_sync_state_pause(void)
1146{
1147 device_links_write_lock();
1148 defer_sync_state_count++;
1149 device_links_write_unlock();
1150}
1151
1152void device_links_supplier_sync_state_resume(void)
1153{
1154 struct device *dev, *tmp;
1155 LIST_HEAD(sync_list);
1156
1157 device_links_write_lock();
1158 if (!defer_sync_state_count) {
1159 WARN(true, "Unmatched sync_state pause/resume!");
1160 goto out;
1161 }
1162 defer_sync_state_count--;
1163 if (defer_sync_state_count)
1164 goto out;
1165
1166 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1167 /*
1168 * Delete from deferred_sync list before queuing it to
1169 * sync_list because defer_sync is used for both lists.
1170 */
1171 list_del_init(&dev->links.defer_sync);
1172 __device_links_queue_sync_state(dev, &sync_list);
1173 }
1174out:
1175 device_links_write_unlock();
1176
1177 device_links_flush_sync_list(&sync_list, NULL);
1178}
1179
1180static int sync_state_resume_initcall(void)
1181{
1182 device_links_supplier_sync_state_resume();
1183 return 0;
1184}
1185late_initcall(sync_state_resume_initcall);
1186
1187static void __device_links_supplier_defer_sync(struct device *sup)
1188{
1189 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1190 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1191}
1192
1193static void device_link_drop_managed(struct device_link *link)
1194{
1195 link->flags &= ~DL_FLAG_MANAGED;
1196 WRITE_ONCE(link->status, DL_STATE_NONE);
1197 kref_put(&link->kref, __device_link_del);
1198}
1199
1200static ssize_t waiting_for_supplier_show(struct device *dev,
1201 struct device_attribute *attr,
1202 char *buf)
1203{
1204 bool val;
1205
1206 device_lock(dev);
1207 val = !list_empty(&dev->fwnode->suppliers);
1208 device_unlock(dev);
1209 return sysfs_emit(buf, "%u\n", val);
1210}
1211static DEVICE_ATTR_RO(waiting_for_supplier);
1212
1213/**
1214 * device_links_force_bind - Prepares device to be force bound
1215 * @dev: Consumer device.
1216 *
1217 * device_bind_driver() force binds a device to a driver without calling any
1218 * driver probe functions. So the consumer really isn't going to wait for any
1219 * supplier before it's bound to the driver. We still want the device link
1220 * states to be sensible when this happens.
1221 *
1222 * In preparation for device_bind_driver(), this function goes through each
1223 * supplier device links and checks if the supplier is bound. If it is, then
1224 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1225 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1226 */
1227void device_links_force_bind(struct device *dev)
1228{
1229 struct device_link *link, *ln;
1230
1231 device_links_write_lock();
1232
1233 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1234 if (!(link->flags & DL_FLAG_MANAGED))
1235 continue;
1236
1237 if (link->status != DL_STATE_AVAILABLE) {
1238 device_link_drop_managed(link);
1239 continue;
1240 }
1241 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1242 }
1243 dev->links.status = DL_DEV_PROBING;
1244
1245 device_links_write_unlock();
1246}
1247
1248/**
1249 * device_links_driver_bound - Update device links after probing its driver.
1250 * @dev: Device to update the links for.
1251 *
1252 * The probe has been successful, so update links from this device to any
1253 * consumers by changing their status to "available".
1254 *
1255 * Also change the status of @dev's links to suppliers to "active".
1256 *
1257 * Links without the DL_FLAG_MANAGED flag set are ignored.
1258 */
1259void device_links_driver_bound(struct device *dev)
1260{
1261 struct device_link *link, *ln;
1262 LIST_HEAD(sync_list);
1263
1264 /*
1265 * If a device binds successfully, it's expected to have created all
1266 * the device links it needs to or make new device links as it needs
1267 * them. So, fw_devlink no longer needs to create device links to any
1268 * of the device's suppliers.
1269 *
1270 * Also, if a child firmware node of this bound device is not added as
1271 * a device by now, assume it is never going to be added and make sure
1272 * other devices don't defer probe indefinitely by waiting for such a
1273 * child device.
1274 */
1275 if (dev->fwnode && dev->fwnode->dev == dev) {
1276 struct fwnode_handle *child;
1277 fwnode_links_purge_suppliers(dev->fwnode);
1278 fwnode_for_each_available_child_node(dev->fwnode, child)
1279 fw_devlink_purge_absent_suppliers(child);
1280 }
1281 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1282
1283 device_links_write_lock();
1284
1285 list_for_each_entry(link, &dev->links.consumers, s_node) {
1286 if (!(link->flags & DL_FLAG_MANAGED))
1287 continue;
1288
1289 /*
1290 * Links created during consumer probe may be in the "consumer
1291 * probe" state to start with if the supplier is still probing
1292 * when they are created and they may become "active" if the
1293 * consumer probe returns first. Skip them here.
1294 */
1295 if (link->status == DL_STATE_CONSUMER_PROBE ||
1296 link->status == DL_STATE_ACTIVE)
1297 continue;
1298
1299 WARN_ON(link->status != DL_STATE_DORMANT);
1300 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1301
1302 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1303 driver_deferred_probe_add(link->consumer);
1304 }
1305
1306 if (defer_sync_state_count)
1307 __device_links_supplier_defer_sync(dev);
1308 else
1309 __device_links_queue_sync_state(dev, &sync_list);
1310
1311 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1312 struct device *supplier;
1313
1314 if (!(link->flags & DL_FLAG_MANAGED))
1315 continue;
1316
1317 supplier = link->supplier;
1318 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1319 /*
1320 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1321 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1322 * save to drop the managed link completely.
1323 */
1324 device_link_drop_managed(link);
1325 } else if (dev_is_best_effort(dev) &&
1326 link->flags & DL_FLAG_INFERRED &&
1327 link->status != DL_STATE_CONSUMER_PROBE &&
1328 !link->supplier->can_match) {
1329 /*
1330 * When dev_is_best_effort() is true, we ignore device
1331 * links to suppliers that don't have a driver. If the
1332 * consumer device still managed to probe, there's no
1333 * point in maintaining a device link in a weird state
1334 * (consumer probed before supplier). So delete it.
1335 */
1336 device_link_drop_managed(link);
1337 } else {
1338 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1339 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1340 }
1341
1342 /*
1343 * This needs to be done even for the deleted
1344 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1345 * device link that was preventing the supplier from getting a
1346 * sync_state() call.
1347 */
1348 if (defer_sync_state_count)
1349 __device_links_supplier_defer_sync(supplier);
1350 else
1351 __device_links_queue_sync_state(supplier, &sync_list);
1352 }
1353
1354 dev->links.status = DL_DEV_DRIVER_BOUND;
1355
1356 device_links_write_unlock();
1357
1358 device_links_flush_sync_list(&sync_list, dev);
1359}
1360
1361/**
1362 * __device_links_no_driver - Update links of a device without a driver.
1363 * @dev: Device without a drvier.
1364 *
1365 * Delete all non-persistent links from this device to any suppliers.
1366 *
1367 * Persistent links stay around, but their status is changed to "available",
1368 * unless they already are in the "supplier unbind in progress" state in which
1369 * case they need not be updated.
1370 *
1371 * Links without the DL_FLAG_MANAGED flag set are ignored.
1372 */
1373static void __device_links_no_driver(struct device *dev)
1374{
1375 struct device_link *link, *ln;
1376
1377 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1378 if (!(link->flags & DL_FLAG_MANAGED))
1379 continue;
1380
1381 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1382 device_link_drop_managed(link);
1383 continue;
1384 }
1385
1386 if (link->status != DL_STATE_CONSUMER_PROBE &&
1387 link->status != DL_STATE_ACTIVE)
1388 continue;
1389
1390 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1391 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1392 } else {
1393 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1394 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1395 }
1396 }
1397
1398 dev->links.status = DL_DEV_NO_DRIVER;
1399}
1400
1401/**
1402 * device_links_no_driver - Update links after failing driver probe.
1403 * @dev: Device whose driver has just failed to probe.
1404 *
1405 * Clean up leftover links to consumers for @dev and invoke
1406 * %__device_links_no_driver() to update links to suppliers for it as
1407 * appropriate.
1408 *
1409 * Links without the DL_FLAG_MANAGED flag set are ignored.
1410 */
1411void device_links_no_driver(struct device *dev)
1412{
1413 struct device_link *link;
1414
1415 device_links_write_lock();
1416
1417 list_for_each_entry(link, &dev->links.consumers, s_node) {
1418 if (!(link->flags & DL_FLAG_MANAGED))
1419 continue;
1420
1421 /*
1422 * The probe has failed, so if the status of the link is
1423 * "consumer probe" or "active", it must have been added by
1424 * a probing consumer while this device was still probing.
1425 * Change its state to "dormant", as it represents a valid
1426 * relationship, but it is not functionally meaningful.
1427 */
1428 if (link->status == DL_STATE_CONSUMER_PROBE ||
1429 link->status == DL_STATE_ACTIVE)
1430 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1431 }
1432
1433 __device_links_no_driver(dev);
1434
1435 device_links_write_unlock();
1436}
1437
1438/**
1439 * device_links_driver_cleanup - Update links after driver removal.
1440 * @dev: Device whose driver has just gone away.
1441 *
1442 * Update links to consumers for @dev by changing their status to "dormant" and
1443 * invoke %__device_links_no_driver() to update links to suppliers for it as
1444 * appropriate.
1445 *
1446 * Links without the DL_FLAG_MANAGED flag set are ignored.
1447 */
1448void device_links_driver_cleanup(struct device *dev)
1449{
1450 struct device_link *link, *ln;
1451
1452 device_links_write_lock();
1453
1454 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1455 if (!(link->flags & DL_FLAG_MANAGED))
1456 continue;
1457
1458 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1459 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1460
1461 /*
1462 * autoremove the links between this @dev and its consumer
1463 * devices that are not active, i.e. where the link state
1464 * has moved to DL_STATE_SUPPLIER_UNBIND.
1465 */
1466 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1467 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1468 device_link_drop_managed(link);
1469
1470 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1471 }
1472
1473 list_del_init(&dev->links.defer_sync);
1474 __device_links_no_driver(dev);
1475
1476 device_links_write_unlock();
1477}
1478
1479/**
1480 * device_links_busy - Check if there are any busy links to consumers.
1481 * @dev: Device to check.
1482 *
1483 * Check each consumer of the device and return 'true' if its link's status
1484 * is one of "consumer probe" or "active" (meaning that the given consumer is
1485 * probing right now or its driver is present). Otherwise, change the link
1486 * state to "supplier unbind" to prevent the consumer from being probed
1487 * successfully going forward.
1488 *
1489 * Return 'false' if there are no probing or active consumers.
1490 *
1491 * Links without the DL_FLAG_MANAGED flag set are ignored.
1492 */
1493bool device_links_busy(struct device *dev)
1494{
1495 struct device_link *link;
1496 bool ret = false;
1497
1498 device_links_write_lock();
1499
1500 list_for_each_entry(link, &dev->links.consumers, s_node) {
1501 if (!(link->flags & DL_FLAG_MANAGED))
1502 continue;
1503
1504 if (link->status == DL_STATE_CONSUMER_PROBE
1505 || link->status == DL_STATE_ACTIVE) {
1506 ret = true;
1507 break;
1508 }
1509 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1510 }
1511
1512 dev->links.status = DL_DEV_UNBINDING;
1513
1514 device_links_write_unlock();
1515 return ret;
1516}
1517
1518/**
1519 * device_links_unbind_consumers - Force unbind consumers of the given device.
1520 * @dev: Device to unbind the consumers of.
1521 *
1522 * Walk the list of links to consumers for @dev and if any of them is in the
1523 * "consumer probe" state, wait for all device probes in progress to complete
1524 * and start over.
1525 *
1526 * If that's not the case, change the status of the link to "supplier unbind"
1527 * and check if the link was in the "active" state. If so, force the consumer
1528 * driver to unbind and start over (the consumer will not re-probe as we have
1529 * changed the state of the link already).
1530 *
1531 * Links without the DL_FLAG_MANAGED flag set are ignored.
1532 */
1533void device_links_unbind_consumers(struct device *dev)
1534{
1535 struct device_link *link;
1536
1537 start:
1538 device_links_write_lock();
1539
1540 list_for_each_entry(link, &dev->links.consumers, s_node) {
1541 enum device_link_state status;
1542
1543 if (!(link->flags & DL_FLAG_MANAGED) ||
1544 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1545 continue;
1546
1547 status = link->status;
1548 if (status == DL_STATE_CONSUMER_PROBE) {
1549 device_links_write_unlock();
1550
1551 wait_for_device_probe();
1552 goto start;
1553 }
1554 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1555 if (status == DL_STATE_ACTIVE) {
1556 struct device *consumer = link->consumer;
1557
1558 get_device(consumer);
1559
1560 device_links_write_unlock();
1561
1562 device_release_driver_internal(consumer, NULL,
1563 consumer->parent);
1564 put_device(consumer);
1565 goto start;
1566 }
1567 }
1568
1569 device_links_write_unlock();
1570}
1571
1572/**
1573 * device_links_purge - Delete existing links to other devices.
1574 * @dev: Target device.
1575 */
1576static void device_links_purge(struct device *dev)
1577{
1578 struct device_link *link, *ln;
1579
1580 if (dev->class == &devlink_class)
1581 return;
1582
1583 /*
1584 * Delete all of the remaining links from this device to any other
1585 * devices (either consumers or suppliers).
1586 */
1587 device_links_write_lock();
1588
1589 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1590 WARN_ON(link->status == DL_STATE_ACTIVE);
1591 __device_link_del(&link->kref);
1592 }
1593
1594 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1595 WARN_ON(link->status != DL_STATE_DORMANT &&
1596 link->status != DL_STATE_NONE);
1597 __device_link_del(&link->kref);
1598 }
1599
1600 device_links_write_unlock();
1601}
1602
1603#define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1604 DL_FLAG_SYNC_STATE_ONLY)
1605#define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1606 DL_FLAG_AUTOPROBE_CONSUMER)
1607#define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1608 DL_FLAG_PM_RUNTIME)
1609
1610static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1611static int __init fw_devlink_setup(char *arg)
1612{
1613 if (!arg)
1614 return -EINVAL;
1615
1616 if (strcmp(arg, "off") == 0) {
1617 fw_devlink_flags = 0;
1618 } else if (strcmp(arg, "permissive") == 0) {
1619 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1620 } else if (strcmp(arg, "on") == 0) {
1621 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1622 } else if (strcmp(arg, "rpm") == 0) {
1623 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1624 }
1625 return 0;
1626}
1627early_param("fw_devlink", fw_devlink_setup);
1628
1629static bool fw_devlink_strict;
1630static int __init fw_devlink_strict_setup(char *arg)
1631{
1632 return kstrtobool(arg, &fw_devlink_strict);
1633}
1634early_param("fw_devlink.strict", fw_devlink_strict_setup);
1635
1636u32 fw_devlink_get_flags(void)
1637{
1638 return fw_devlink_flags;
1639}
1640
1641static bool fw_devlink_is_permissive(void)
1642{
1643 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1644}
1645
1646bool fw_devlink_is_strict(void)
1647{
1648 return fw_devlink_strict && !fw_devlink_is_permissive();
1649}
1650
1651static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1652{
1653 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1654 return;
1655
1656 fwnode_call_int_op(fwnode, add_links);
1657 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1658}
1659
1660static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1661{
1662 struct fwnode_handle *child = NULL;
1663
1664 fw_devlink_parse_fwnode(fwnode);
1665
1666 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1667 fw_devlink_parse_fwtree(child);
1668}
1669
1670static void fw_devlink_relax_link(struct device_link *link)
1671{
1672 if (!(link->flags & DL_FLAG_INFERRED))
1673 return;
1674
1675 if (link->flags == (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE))
1676 return;
1677
1678 pm_runtime_drop_link(link);
1679 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1680 dev_dbg(link->consumer, "Relaxing link with %s\n",
1681 dev_name(link->supplier));
1682}
1683
1684static int fw_devlink_no_driver(struct device *dev, void *data)
1685{
1686 struct device_link *link = to_devlink(dev);
1687
1688 if (!link->supplier->can_match)
1689 fw_devlink_relax_link(link);
1690
1691 return 0;
1692}
1693
1694void fw_devlink_drivers_done(void)
1695{
1696 fw_devlink_drv_reg_done = true;
1697 device_links_write_lock();
1698 class_for_each_device(&devlink_class, NULL, NULL,
1699 fw_devlink_no_driver);
1700 device_links_write_unlock();
1701}
1702
1703/**
1704 * wait_for_init_devices_probe - Try to probe any device needed for init
1705 *
1706 * Some devices might need to be probed and bound successfully before the kernel
1707 * boot sequence can finish and move on to init/userspace. For example, a
1708 * network interface might need to be bound to be able to mount a NFS rootfs.
1709 *
1710 * With fw_devlink=on by default, some of these devices might be blocked from
1711 * probing because they are waiting on a optional supplier that doesn't have a
1712 * driver. While fw_devlink will eventually identify such devices and unblock
1713 * the probing automatically, it might be too late by the time it unblocks the
1714 * probing of devices. For example, the IP4 autoconfig might timeout before
1715 * fw_devlink unblocks probing of the network interface.
1716 *
1717 * This function is available to temporarily try and probe all devices that have
1718 * a driver even if some of their suppliers haven't been added or don't have
1719 * drivers.
1720 *
1721 * The drivers can then decide which of the suppliers are optional vs mandatory
1722 * and probe the device if possible. By the time this function returns, all such
1723 * "best effort" probes are guaranteed to be completed. If a device successfully
1724 * probes in this mode, we delete all fw_devlink discovered dependencies of that
1725 * device where the supplier hasn't yet probed successfully because they have to
1726 * be optional dependencies.
1727 *
1728 * Any devices that didn't successfully probe go back to being treated as if
1729 * this function was never called.
1730 *
1731 * This also means that some devices that aren't needed for init and could have
1732 * waited for their optional supplier to probe (when the supplier's module is
1733 * loaded later on) would end up probing prematurely with limited functionality.
1734 * So call this function only when boot would fail without it.
1735 */
1736void __init wait_for_init_devices_probe(void)
1737{
1738 if (!fw_devlink_flags || fw_devlink_is_permissive())
1739 return;
1740
1741 /*
1742 * Wait for all ongoing probes to finish so that the "best effort" is
1743 * only applied to devices that can't probe otherwise.
1744 */
1745 wait_for_device_probe();
1746
1747 pr_info("Trying to probe devices needed for running init ...\n");
1748 fw_devlink_best_effort = true;
1749 driver_deferred_probe_trigger();
1750
1751 /*
1752 * Wait for all "best effort" probes to finish before going back to
1753 * normal enforcement.
1754 */
1755 wait_for_device_probe();
1756 fw_devlink_best_effort = false;
1757}
1758
1759static void fw_devlink_unblock_consumers(struct device *dev)
1760{
1761 struct device_link *link;
1762
1763 if (!fw_devlink_flags || fw_devlink_is_permissive())
1764 return;
1765
1766 device_links_write_lock();
1767 list_for_each_entry(link, &dev->links.consumers, s_node)
1768 fw_devlink_relax_link(link);
1769 device_links_write_unlock();
1770}
1771
1772/**
1773 * fw_devlink_relax_cycle - Convert cyclic links to SYNC_STATE_ONLY links
1774 * @con: Device to check dependencies for.
1775 * @sup: Device to check against.
1776 *
1777 * Check if @sup depends on @con or any device dependent on it (its child or
1778 * its consumer etc). When such a cyclic dependency is found, convert all
1779 * device links created solely by fw_devlink into SYNC_STATE_ONLY device links.
1780 * This is the equivalent of doing fw_devlink=permissive just between the
1781 * devices in the cycle. We need to do this because, at this point, fw_devlink
1782 * can't tell which of these dependencies is not a real dependency.
1783 *
1784 * Return 1 if a cycle is found. Otherwise, return 0.
1785 */
1786static int fw_devlink_relax_cycle(struct device *con, void *sup)
1787{
1788 struct device_link *link;
1789 int ret;
1790
1791 if (con == sup)
1792 return 1;
1793
1794 ret = device_for_each_child(con, sup, fw_devlink_relax_cycle);
1795 if (ret)
1796 return ret;
1797
1798 list_for_each_entry(link, &con->links.consumers, s_node) {
1799 if ((link->flags & ~DL_FLAG_INFERRED) ==
1800 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
1801 continue;
1802
1803 if (!fw_devlink_relax_cycle(link->consumer, sup))
1804 continue;
1805
1806 ret = 1;
1807
1808 fw_devlink_relax_link(link);
1809 }
1810 return ret;
1811}
1812
1813/**
1814 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
1815 * @con: consumer device for the device link
1816 * @sup_handle: fwnode handle of supplier
1817 * @flags: devlink flags
1818 *
1819 * This function will try to create a device link between the consumer device
1820 * @con and the supplier device represented by @sup_handle.
1821 *
1822 * The supplier has to be provided as a fwnode because incorrect cycles in
1823 * fwnode links can sometimes cause the supplier device to never be created.
1824 * This function detects such cases and returns an error if it cannot create a
1825 * device link from the consumer to a missing supplier.
1826 *
1827 * Returns,
1828 * 0 on successfully creating a device link
1829 * -EINVAL if the device link cannot be created as expected
1830 * -EAGAIN if the device link cannot be created right now, but it may be
1831 * possible to do that in the future
1832 */
1833static int fw_devlink_create_devlink(struct device *con,
1834 struct fwnode_handle *sup_handle, u32 flags)
1835{
1836 struct device *sup_dev;
1837 int ret = 0;
1838
1839 /*
1840 * In some cases, a device P might also be a supplier to its child node
1841 * C. However, this would defer the probe of C until the probe of P
1842 * completes successfully. This is perfectly fine in the device driver
1843 * model. device_add() doesn't guarantee probe completion of the device
1844 * by the time it returns.
1845 *
1846 * However, there are a few drivers that assume C will finish probing
1847 * as soon as it's added and before P finishes probing. So, we provide
1848 * a flag to let fw_devlink know not to delay the probe of C until the
1849 * probe of P completes successfully.
1850 *
1851 * When such a flag is set, we can't create device links where P is the
1852 * supplier of C as that would delay the probe of C.
1853 */
1854 if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD &&
1855 fwnode_is_ancestor_of(sup_handle, con->fwnode))
1856 return -EINVAL;
1857
1858 sup_dev = get_dev_from_fwnode(sup_handle);
1859 if (sup_dev) {
1860 /*
1861 * If it's one of those drivers that don't actually bind to
1862 * their device using driver core, then don't wait on this
1863 * supplier device indefinitely.
1864 */
1865 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
1866 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
1867 ret = -EINVAL;
1868 goto out;
1869 }
1870
1871 /*
1872 * If this fails, it is due to cycles in device links. Just
1873 * give up on this link and treat it as invalid.
1874 */
1875 if (!device_link_add(con, sup_dev, flags) &&
1876 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
1877 dev_info(con, "Fixing up cyclic dependency with %s\n",
1878 dev_name(sup_dev));
1879 device_links_write_lock();
1880 fw_devlink_relax_cycle(con, sup_dev);
1881 device_links_write_unlock();
1882 device_link_add(con, sup_dev,
1883 FW_DEVLINK_FLAGS_PERMISSIVE);
1884 ret = -EINVAL;
1885 }
1886
1887 goto out;
1888 }
1889
1890 /* Supplier that's already initialized without a struct device. */
1891 if (sup_handle->flags & FWNODE_FLAG_INITIALIZED)
1892 return -EINVAL;
1893
1894 /*
1895 * DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports
1896 * cycles. So cycle detection isn't necessary and shouldn't be
1897 * done.
1898 */
1899 if (flags & DL_FLAG_SYNC_STATE_ONLY)
1900 return -EAGAIN;
1901
1902 /*
1903 * If we can't find the supplier device from its fwnode, it might be
1904 * due to a cyclic dependency between fwnodes. Some of these cycles can
1905 * be broken by applying logic. Check for these types of cycles and
1906 * break them so that devices in the cycle probe properly.
1907 *
1908 * If the supplier's parent is dependent on the consumer, then the
1909 * consumer and supplier have a cyclic dependency. Since fw_devlink
1910 * can't tell which of the inferred dependencies are incorrect, don't
1911 * enforce probe ordering between any of the devices in this cyclic
1912 * dependency. Do this by relaxing all the fw_devlink device links in
1913 * this cycle and by treating the fwnode link between the consumer and
1914 * the supplier as an invalid dependency.
1915 */
1916 sup_dev = fwnode_get_next_parent_dev(sup_handle);
1917 if (sup_dev && device_is_dependent(con, sup_dev)) {
1918 dev_info(con, "Fixing up cyclic dependency with %pfwP (%s)\n",
1919 sup_handle, dev_name(sup_dev));
1920 device_links_write_lock();
1921 fw_devlink_relax_cycle(con, sup_dev);
1922 device_links_write_unlock();
1923 ret = -EINVAL;
1924 } else {
1925 /*
1926 * Can't check for cycles or no cycles. So let's try
1927 * again later.
1928 */
1929 ret = -EAGAIN;
1930 }
1931
1932out:
1933 put_device(sup_dev);
1934 return ret;
1935}
1936
1937/**
1938 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
1939 * @dev: Device that needs to be linked to its consumers
1940 *
1941 * This function looks at all the consumer fwnodes of @dev and creates device
1942 * links between the consumer device and @dev (supplier).
1943 *
1944 * If the consumer device has not been added yet, then this function creates a
1945 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
1946 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
1947 * sync_state() callback before the real consumer device gets to be added and
1948 * then probed.
1949 *
1950 * Once device links are created from the real consumer to @dev (supplier), the
1951 * fwnode links are deleted.
1952 */
1953static void __fw_devlink_link_to_consumers(struct device *dev)
1954{
1955 struct fwnode_handle *fwnode = dev->fwnode;
1956 struct fwnode_link *link, *tmp;
1957
1958 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
1959 u32 dl_flags = fw_devlink_get_flags();
1960 struct device *con_dev;
1961 bool own_link = true;
1962 int ret;
1963
1964 con_dev = get_dev_from_fwnode(link->consumer);
1965 /*
1966 * If consumer device is not available yet, make a "proxy"
1967 * SYNC_STATE_ONLY link from the consumer's parent device to
1968 * the supplier device. This is necessary to make sure the
1969 * supplier doesn't get a sync_state() callback before the real
1970 * consumer can create a device link to the supplier.
1971 *
1972 * This proxy link step is needed to handle the case where the
1973 * consumer's parent device is added before the supplier.
1974 */
1975 if (!con_dev) {
1976 con_dev = fwnode_get_next_parent_dev(link->consumer);
1977 /*
1978 * However, if the consumer's parent device is also the
1979 * parent of the supplier, don't create a
1980 * consumer-supplier link from the parent to its child
1981 * device. Such a dependency is impossible.
1982 */
1983 if (con_dev &&
1984 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
1985 put_device(con_dev);
1986 con_dev = NULL;
1987 } else {
1988 own_link = false;
1989 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1990 }
1991 }
1992
1993 if (!con_dev)
1994 continue;
1995
1996 ret = fw_devlink_create_devlink(con_dev, fwnode, dl_flags);
1997 put_device(con_dev);
1998 if (!own_link || ret == -EAGAIN)
1999 continue;
2000
2001 __fwnode_link_del(link);
2002 }
2003}
2004
2005/**
2006 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
2007 * @dev: The consumer device that needs to be linked to its suppliers
2008 * @fwnode: Root of the fwnode tree that is used to create device links
2009 *
2010 * This function looks at all the supplier fwnodes of fwnode tree rooted at
2011 * @fwnode and creates device links between @dev (consumer) and all the
2012 * supplier devices of the entire fwnode tree at @fwnode.
2013 *
2014 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
2015 * and the real suppliers of @dev. Once these device links are created, the
2016 * fwnode links are deleted. When such device links are successfully created,
2017 * this function is called recursively on those supplier devices. This is
2018 * needed to detect and break some invalid cycles in fwnode links. See
2019 * fw_devlink_create_devlink() for more details.
2020 *
2021 * In addition, it also looks at all the suppliers of the entire fwnode tree
2022 * because some of the child devices of @dev that have not been added yet
2023 * (because @dev hasn't probed) might already have their suppliers added to
2024 * driver core. So, this function creates SYNC_STATE_ONLY device links between
2025 * @dev (consumer) and these suppliers to make sure they don't execute their
2026 * sync_state() callbacks before these child devices have a chance to create
2027 * their device links. The fwnode links that correspond to the child devices
2028 * aren't delete because they are needed later to create the device links
2029 * between the real consumer and supplier devices.
2030 */
2031static void __fw_devlink_link_to_suppliers(struct device *dev,
2032 struct fwnode_handle *fwnode)
2033{
2034 bool own_link = (dev->fwnode == fwnode);
2035 struct fwnode_link *link, *tmp;
2036 struct fwnode_handle *child = NULL;
2037 u32 dl_flags;
2038
2039 if (own_link)
2040 dl_flags = fw_devlink_get_flags();
2041 else
2042 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
2043
2044 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
2045 int ret;
2046 struct device *sup_dev;
2047 struct fwnode_handle *sup = link->supplier;
2048
2049 ret = fw_devlink_create_devlink(dev, sup, dl_flags);
2050 if (!own_link || ret == -EAGAIN)
2051 continue;
2052
2053 __fwnode_link_del(link);
2054
2055 /* If no device link was created, nothing more to do. */
2056 if (ret)
2057 continue;
2058
2059 /*
2060 * If a device link was successfully created to a supplier, we
2061 * now need to try and link the supplier to all its suppliers.
2062 *
2063 * This is needed to detect and delete false dependencies in
2064 * fwnode links that haven't been converted to a device link
2065 * yet. See comments in fw_devlink_create_devlink() for more
2066 * details on the false dependency.
2067 *
2068 * Without deleting these false dependencies, some devices will
2069 * never probe because they'll keep waiting for their false
2070 * dependency fwnode links to be converted to device links.
2071 */
2072 sup_dev = get_dev_from_fwnode(sup);
2073 __fw_devlink_link_to_suppliers(sup_dev, sup_dev->fwnode);
2074 put_device(sup_dev);
2075 }
2076
2077 /*
2078 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
2079 * all the descendants. This proxy link step is needed to handle the
2080 * case where the supplier is added before the consumer's parent device
2081 * (@dev).
2082 */
2083 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
2084 __fw_devlink_link_to_suppliers(dev, child);
2085}
2086
2087static void fw_devlink_link_device(struct device *dev)
2088{
2089 struct fwnode_handle *fwnode = dev->fwnode;
2090
2091 if (!fw_devlink_flags)
2092 return;
2093
2094 fw_devlink_parse_fwtree(fwnode);
2095
2096 mutex_lock(&fwnode_link_lock);
2097 __fw_devlink_link_to_consumers(dev);
2098 __fw_devlink_link_to_suppliers(dev, fwnode);
2099 mutex_unlock(&fwnode_link_lock);
2100}
2101
2102/* Device links support end. */
2103
2104int (*platform_notify)(struct device *dev) = NULL;
2105int (*platform_notify_remove)(struct device *dev) = NULL;
2106static struct kobject *dev_kobj;
2107struct kobject *sysfs_dev_char_kobj;
2108struct kobject *sysfs_dev_block_kobj;
2109
2110static DEFINE_MUTEX(device_hotplug_lock);
2111
2112void lock_device_hotplug(void)
2113{
2114 mutex_lock(&device_hotplug_lock);
2115}
2116
2117void unlock_device_hotplug(void)
2118{
2119 mutex_unlock(&device_hotplug_lock);
2120}
2121
2122int lock_device_hotplug_sysfs(void)
2123{
2124 if (mutex_trylock(&device_hotplug_lock))
2125 return 0;
2126
2127 /* Avoid busy looping (5 ms of sleep should do). */
2128 msleep(5);
2129 return restart_syscall();
2130}
2131
2132#ifdef CONFIG_BLOCK
2133static inline int device_is_not_partition(struct device *dev)
2134{
2135 return !(dev->type == &part_type);
2136}
2137#else
2138static inline int device_is_not_partition(struct device *dev)
2139{
2140 return 1;
2141}
2142#endif
2143
2144static void device_platform_notify(struct device *dev)
2145{
2146 acpi_device_notify(dev);
2147
2148 software_node_notify(dev);
2149
2150 if (platform_notify)
2151 platform_notify(dev);
2152}
2153
2154static void device_platform_notify_remove(struct device *dev)
2155{
2156 acpi_device_notify_remove(dev);
2157
2158 software_node_notify_remove(dev);
2159
2160 if (platform_notify_remove)
2161 platform_notify_remove(dev);
2162}
2163
2164/**
2165 * dev_driver_string - Return a device's driver name, if at all possible
2166 * @dev: struct device to get the name of
2167 *
2168 * Will return the device's driver's name if it is bound to a device. If
2169 * the device is not bound to a driver, it will return the name of the bus
2170 * it is attached to. If it is not attached to a bus either, an empty
2171 * string will be returned.
2172 */
2173const char *dev_driver_string(const struct device *dev)
2174{
2175 struct device_driver *drv;
2176
2177 /* dev->driver can change to NULL underneath us because of unbinding,
2178 * so be careful about accessing it. dev->bus and dev->class should
2179 * never change once they are set, so they don't need special care.
2180 */
2181 drv = READ_ONCE(dev->driver);
2182 return drv ? drv->name : dev_bus_name(dev);
2183}
2184EXPORT_SYMBOL(dev_driver_string);
2185
2186#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2187
2188static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2189 char *buf)
2190{
2191 struct device_attribute *dev_attr = to_dev_attr(attr);
2192 struct device *dev = kobj_to_dev(kobj);
2193 ssize_t ret = -EIO;
2194
2195 if (dev_attr->show)
2196 ret = dev_attr->show(dev, dev_attr, buf);
2197 if (ret >= (ssize_t)PAGE_SIZE) {
2198 printk("dev_attr_show: %pS returned bad count\n",
2199 dev_attr->show);
2200 }
2201 return ret;
2202}
2203
2204static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2205 const char *buf, size_t count)
2206{
2207 struct device_attribute *dev_attr = to_dev_attr(attr);
2208 struct device *dev = kobj_to_dev(kobj);
2209 ssize_t ret = -EIO;
2210
2211 if (dev_attr->store)
2212 ret = dev_attr->store(dev, dev_attr, buf, count);
2213 return ret;
2214}
2215
2216static const struct sysfs_ops dev_sysfs_ops = {
2217 .show = dev_attr_show,
2218 .store = dev_attr_store,
2219};
2220
2221#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2222
2223ssize_t device_store_ulong(struct device *dev,
2224 struct device_attribute *attr,
2225 const char *buf, size_t size)
2226{
2227 struct dev_ext_attribute *ea = to_ext_attr(attr);
2228 int ret;
2229 unsigned long new;
2230
2231 ret = kstrtoul(buf, 0, &new);
2232 if (ret)
2233 return ret;
2234 *(unsigned long *)(ea->var) = new;
2235 /* Always return full write size even if we didn't consume all */
2236 return size;
2237}
2238EXPORT_SYMBOL_GPL(device_store_ulong);
2239
2240ssize_t device_show_ulong(struct device *dev,
2241 struct device_attribute *attr,
2242 char *buf)
2243{
2244 struct dev_ext_attribute *ea = to_ext_attr(attr);
2245 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2246}
2247EXPORT_SYMBOL_GPL(device_show_ulong);
2248
2249ssize_t device_store_int(struct device *dev,
2250 struct device_attribute *attr,
2251 const char *buf, size_t size)
2252{
2253 struct dev_ext_attribute *ea = to_ext_attr(attr);
2254 int ret;
2255 long new;
2256
2257 ret = kstrtol(buf, 0, &new);
2258 if (ret)
2259 return ret;
2260
2261 if (new > INT_MAX || new < INT_MIN)
2262 return -EINVAL;
2263 *(int *)(ea->var) = new;
2264 /* Always return full write size even if we didn't consume all */
2265 return size;
2266}
2267EXPORT_SYMBOL_GPL(device_store_int);
2268
2269ssize_t device_show_int(struct device *dev,
2270 struct device_attribute *attr,
2271 char *buf)
2272{
2273 struct dev_ext_attribute *ea = to_ext_attr(attr);
2274
2275 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2276}
2277EXPORT_SYMBOL_GPL(device_show_int);
2278
2279ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2280 const char *buf, size_t size)
2281{
2282 struct dev_ext_attribute *ea = to_ext_attr(attr);
2283
2284 if (kstrtobool(buf, ea->var) < 0)
2285 return -EINVAL;
2286
2287 return size;
2288}
2289EXPORT_SYMBOL_GPL(device_store_bool);
2290
2291ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2292 char *buf)
2293{
2294 struct dev_ext_attribute *ea = to_ext_attr(attr);
2295
2296 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2297}
2298EXPORT_SYMBOL_GPL(device_show_bool);
2299
2300/**
2301 * device_release - free device structure.
2302 * @kobj: device's kobject.
2303 *
2304 * This is called once the reference count for the object
2305 * reaches 0. We forward the call to the device's release
2306 * method, which should handle actually freeing the structure.
2307 */
2308static void device_release(struct kobject *kobj)
2309{
2310 struct device *dev = kobj_to_dev(kobj);
2311 struct device_private *p = dev->p;
2312
2313 /*
2314 * Some platform devices are driven without driver attached
2315 * and managed resources may have been acquired. Make sure
2316 * all resources are released.
2317 *
2318 * Drivers still can add resources into device after device
2319 * is deleted but alive, so release devres here to avoid
2320 * possible memory leak.
2321 */
2322 devres_release_all(dev);
2323
2324 kfree(dev->dma_range_map);
2325
2326 if (dev->release)
2327 dev->release(dev);
2328 else if (dev->type && dev->type->release)
2329 dev->type->release(dev);
2330 else if (dev->class && dev->class->dev_release)
2331 dev->class->dev_release(dev);
2332 else
2333 WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
2334 dev_name(dev));
2335 kfree(p);
2336}
2337
2338static const void *device_namespace(const struct kobject *kobj)
2339{
2340 const struct device *dev = kobj_to_dev(kobj);
2341 const void *ns = NULL;
2342
2343 if (dev->class && dev->class->ns_type)
2344 ns = dev->class->namespace(dev);
2345
2346 return ns;
2347}
2348
2349static void device_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2350{
2351 const struct device *dev = kobj_to_dev(kobj);
2352
2353 if (dev->class && dev->class->get_ownership)
2354 dev->class->get_ownership(dev, uid, gid);
2355}
2356
2357static struct kobj_type device_ktype = {
2358 .release = device_release,
2359 .sysfs_ops = &dev_sysfs_ops,
2360 .namespace = device_namespace,
2361 .get_ownership = device_get_ownership,
2362};
2363
2364
2365static int dev_uevent_filter(const struct kobject *kobj)
2366{
2367 const struct kobj_type *ktype = get_ktype(kobj);
2368
2369 if (ktype == &device_ktype) {
2370 const struct device *dev = kobj_to_dev(kobj);
2371 if (dev->bus)
2372 return 1;
2373 if (dev->class)
2374 return 1;
2375 }
2376 return 0;
2377}
2378
2379static const char *dev_uevent_name(const struct kobject *kobj)
2380{
2381 const struct device *dev = kobj_to_dev(kobj);
2382
2383 if (dev->bus)
2384 return dev->bus->name;
2385 if (dev->class)
2386 return dev->class->name;
2387 return NULL;
2388}
2389
2390static int dev_uevent(struct kobject *kobj, struct kobj_uevent_env *env)
2391{
2392 struct device *dev = kobj_to_dev(kobj);
2393 int retval = 0;
2394
2395 /* add device node properties if present */
2396 if (MAJOR(dev->devt)) {
2397 const char *tmp;
2398 const char *name;
2399 umode_t mode = 0;
2400 kuid_t uid = GLOBAL_ROOT_UID;
2401 kgid_t gid = GLOBAL_ROOT_GID;
2402
2403 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2404 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2405 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2406 if (name) {
2407 add_uevent_var(env, "DEVNAME=%s", name);
2408 if (mode)
2409 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2410 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2411 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2412 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2413 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2414 kfree(tmp);
2415 }
2416 }
2417
2418 if (dev->type && dev->type->name)
2419 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2420
2421 if (dev->driver)
2422 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2423
2424 /* Add common DT information about the device */
2425 of_device_uevent(dev, env);
2426
2427 /* have the bus specific function add its stuff */
2428 if (dev->bus && dev->bus->uevent) {
2429 retval = dev->bus->uevent(dev, env);
2430 if (retval)
2431 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2432 dev_name(dev), __func__, retval);
2433 }
2434
2435 /* have the class specific function add its stuff */
2436 if (dev->class && dev->class->dev_uevent) {
2437 retval = dev->class->dev_uevent(dev, env);
2438 if (retval)
2439 pr_debug("device: '%s': %s: class uevent() "
2440 "returned %d\n", dev_name(dev),
2441 __func__, retval);
2442 }
2443
2444 /* have the device type specific function add its stuff */
2445 if (dev->type && dev->type->uevent) {
2446 retval = dev->type->uevent(dev, env);
2447 if (retval)
2448 pr_debug("device: '%s': %s: dev_type uevent() "
2449 "returned %d\n", dev_name(dev),
2450 __func__, retval);
2451 }
2452
2453 return retval;
2454}
2455
2456static const struct kset_uevent_ops device_uevent_ops = {
2457 .filter = dev_uevent_filter,
2458 .name = dev_uevent_name,
2459 .uevent = dev_uevent,
2460};
2461
2462static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2463 char *buf)
2464{
2465 struct kobject *top_kobj;
2466 struct kset *kset;
2467 struct kobj_uevent_env *env = NULL;
2468 int i;
2469 int len = 0;
2470 int retval;
2471
2472 /* search the kset, the device belongs to */
2473 top_kobj = &dev->kobj;
2474 while (!top_kobj->kset && top_kobj->parent)
2475 top_kobj = top_kobj->parent;
2476 if (!top_kobj->kset)
2477 goto out;
2478
2479 kset = top_kobj->kset;
2480 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2481 goto out;
2482
2483 /* respect filter */
2484 if (kset->uevent_ops && kset->uevent_ops->filter)
2485 if (!kset->uevent_ops->filter(&dev->kobj))
2486 goto out;
2487
2488 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2489 if (!env)
2490 return -ENOMEM;
2491
2492 /* let the kset specific function add its keys */
2493 retval = kset->uevent_ops->uevent(&dev->kobj, env);
2494 if (retval)
2495 goto out;
2496
2497 /* copy keys to file */
2498 for (i = 0; i < env->envp_idx; i++)
2499 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2500out:
2501 kfree(env);
2502 return len;
2503}
2504
2505static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2506 const char *buf, size_t count)
2507{
2508 int rc;
2509
2510 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2511
2512 if (rc) {
2513 dev_err(dev, "uevent: failed to send synthetic uevent: %d\n", rc);
2514 return rc;
2515 }
2516
2517 return count;
2518}
2519static DEVICE_ATTR_RW(uevent);
2520
2521static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2522 char *buf)
2523{
2524 bool val;
2525
2526 device_lock(dev);
2527 val = !dev->offline;
2528 device_unlock(dev);
2529 return sysfs_emit(buf, "%u\n", val);
2530}
2531
2532static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2533 const char *buf, size_t count)
2534{
2535 bool val;
2536 int ret;
2537
2538 ret = kstrtobool(buf, &val);
2539 if (ret < 0)
2540 return ret;
2541
2542 ret = lock_device_hotplug_sysfs();
2543 if (ret)
2544 return ret;
2545
2546 ret = val ? device_online(dev) : device_offline(dev);
2547 unlock_device_hotplug();
2548 return ret < 0 ? ret : count;
2549}
2550static DEVICE_ATTR_RW(online);
2551
2552static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
2553 char *buf)
2554{
2555 const char *loc;
2556
2557 switch (dev->removable) {
2558 case DEVICE_REMOVABLE:
2559 loc = "removable";
2560 break;
2561 case DEVICE_FIXED:
2562 loc = "fixed";
2563 break;
2564 default:
2565 loc = "unknown";
2566 }
2567 return sysfs_emit(buf, "%s\n", loc);
2568}
2569static DEVICE_ATTR_RO(removable);
2570
2571int device_add_groups(struct device *dev, const struct attribute_group **groups)
2572{
2573 return sysfs_create_groups(&dev->kobj, groups);
2574}
2575EXPORT_SYMBOL_GPL(device_add_groups);
2576
2577void device_remove_groups(struct device *dev,
2578 const struct attribute_group **groups)
2579{
2580 sysfs_remove_groups(&dev->kobj, groups);
2581}
2582EXPORT_SYMBOL_GPL(device_remove_groups);
2583
2584union device_attr_group_devres {
2585 const struct attribute_group *group;
2586 const struct attribute_group **groups;
2587};
2588
2589static void devm_attr_group_remove(struct device *dev, void *res)
2590{
2591 union device_attr_group_devres *devres = res;
2592 const struct attribute_group *group = devres->group;
2593
2594 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2595 sysfs_remove_group(&dev->kobj, group);
2596}
2597
2598static void devm_attr_groups_remove(struct device *dev, void *res)
2599{
2600 union device_attr_group_devres *devres = res;
2601 const struct attribute_group **groups = devres->groups;
2602
2603 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2604 sysfs_remove_groups(&dev->kobj, groups);
2605}
2606
2607/**
2608 * devm_device_add_group - given a device, create a managed attribute group
2609 * @dev: The device to create the group for
2610 * @grp: The attribute group to create
2611 *
2612 * This function creates a group for the first time. It will explicitly
2613 * warn and error if any of the attribute files being created already exist.
2614 *
2615 * Returns 0 on success or error code on failure.
2616 */
2617int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2618{
2619 union device_attr_group_devres *devres;
2620 int error;
2621
2622 devres = devres_alloc(devm_attr_group_remove,
2623 sizeof(*devres), GFP_KERNEL);
2624 if (!devres)
2625 return -ENOMEM;
2626
2627 error = sysfs_create_group(&dev->kobj, grp);
2628 if (error) {
2629 devres_free(devres);
2630 return error;
2631 }
2632
2633 devres->group = grp;
2634 devres_add(dev, devres);
2635 return 0;
2636}
2637EXPORT_SYMBOL_GPL(devm_device_add_group);
2638
2639/**
2640 * devm_device_add_groups - create a bunch of managed attribute groups
2641 * @dev: The device to create the group for
2642 * @groups: The attribute groups to create, NULL terminated
2643 *
2644 * This function creates a bunch of managed attribute groups. If an error
2645 * occurs when creating a group, all previously created groups will be
2646 * removed, unwinding everything back to the original state when this
2647 * function was called. It will explicitly warn and error if any of the
2648 * attribute files being created already exist.
2649 *
2650 * Returns 0 on success or error code from sysfs_create_group on failure.
2651 */
2652int devm_device_add_groups(struct device *dev,
2653 const struct attribute_group **groups)
2654{
2655 union device_attr_group_devres *devres;
2656 int error;
2657
2658 devres = devres_alloc(devm_attr_groups_remove,
2659 sizeof(*devres), GFP_KERNEL);
2660 if (!devres)
2661 return -ENOMEM;
2662
2663 error = sysfs_create_groups(&dev->kobj, groups);
2664 if (error) {
2665 devres_free(devres);
2666 return error;
2667 }
2668
2669 devres->groups = groups;
2670 devres_add(dev, devres);
2671 return 0;
2672}
2673EXPORT_SYMBOL_GPL(devm_device_add_groups);
2674
2675static int device_add_attrs(struct device *dev)
2676{
2677 struct class *class = dev->class;
2678 const struct device_type *type = dev->type;
2679 int error;
2680
2681 if (class) {
2682 error = device_add_groups(dev, class->dev_groups);
2683 if (error)
2684 return error;
2685 }
2686
2687 if (type) {
2688 error = device_add_groups(dev, type->groups);
2689 if (error)
2690 goto err_remove_class_groups;
2691 }
2692
2693 error = device_add_groups(dev, dev->groups);
2694 if (error)
2695 goto err_remove_type_groups;
2696
2697 if (device_supports_offline(dev) && !dev->offline_disabled) {
2698 error = device_create_file(dev, &dev_attr_online);
2699 if (error)
2700 goto err_remove_dev_groups;
2701 }
2702
2703 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2704 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2705 if (error)
2706 goto err_remove_dev_online;
2707 }
2708
2709 if (dev_removable_is_valid(dev)) {
2710 error = device_create_file(dev, &dev_attr_removable);
2711 if (error)
2712 goto err_remove_dev_waiting_for_supplier;
2713 }
2714
2715 if (dev_add_physical_location(dev)) {
2716 error = device_add_group(dev,
2717 &dev_attr_physical_location_group);
2718 if (error)
2719 goto err_remove_dev_removable;
2720 }
2721
2722 return 0;
2723
2724 err_remove_dev_removable:
2725 device_remove_file(dev, &dev_attr_removable);
2726 err_remove_dev_waiting_for_supplier:
2727 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2728 err_remove_dev_online:
2729 device_remove_file(dev, &dev_attr_online);
2730 err_remove_dev_groups:
2731 device_remove_groups(dev, dev->groups);
2732 err_remove_type_groups:
2733 if (type)
2734 device_remove_groups(dev, type->groups);
2735 err_remove_class_groups:
2736 if (class)
2737 device_remove_groups(dev, class->dev_groups);
2738
2739 return error;
2740}
2741
2742static void device_remove_attrs(struct device *dev)
2743{
2744 struct class *class = dev->class;
2745 const struct device_type *type = dev->type;
2746
2747 if (dev->physical_location) {
2748 device_remove_group(dev, &dev_attr_physical_location_group);
2749 kfree(dev->physical_location);
2750 }
2751
2752 device_remove_file(dev, &dev_attr_removable);
2753 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2754 device_remove_file(dev, &dev_attr_online);
2755 device_remove_groups(dev, dev->groups);
2756
2757 if (type)
2758 device_remove_groups(dev, type->groups);
2759
2760 if (class)
2761 device_remove_groups(dev, class->dev_groups);
2762}
2763
2764static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2765 char *buf)
2766{
2767 return print_dev_t(buf, dev->devt);
2768}
2769static DEVICE_ATTR_RO(dev);
2770
2771/* /sys/devices/ */
2772struct kset *devices_kset;
2773
2774/**
2775 * devices_kset_move_before - Move device in the devices_kset's list.
2776 * @deva: Device to move.
2777 * @devb: Device @deva should come before.
2778 */
2779static void devices_kset_move_before(struct device *deva, struct device *devb)
2780{
2781 if (!devices_kset)
2782 return;
2783 pr_debug("devices_kset: Moving %s before %s\n",
2784 dev_name(deva), dev_name(devb));
2785 spin_lock(&devices_kset->list_lock);
2786 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2787 spin_unlock(&devices_kset->list_lock);
2788}
2789
2790/**
2791 * devices_kset_move_after - Move device in the devices_kset's list.
2792 * @deva: Device to move
2793 * @devb: Device @deva should come after.
2794 */
2795static void devices_kset_move_after(struct device *deva, struct device *devb)
2796{
2797 if (!devices_kset)
2798 return;
2799 pr_debug("devices_kset: Moving %s after %s\n",
2800 dev_name(deva), dev_name(devb));
2801 spin_lock(&devices_kset->list_lock);
2802 list_move(&deva->kobj.entry, &devb->kobj.entry);
2803 spin_unlock(&devices_kset->list_lock);
2804}
2805
2806/**
2807 * devices_kset_move_last - move the device to the end of devices_kset's list.
2808 * @dev: device to move
2809 */
2810void devices_kset_move_last(struct device *dev)
2811{
2812 if (!devices_kset)
2813 return;
2814 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2815 spin_lock(&devices_kset->list_lock);
2816 list_move_tail(&dev->kobj.entry, &devices_kset->list);
2817 spin_unlock(&devices_kset->list_lock);
2818}
2819
2820/**
2821 * device_create_file - create sysfs attribute file for device.
2822 * @dev: device.
2823 * @attr: device attribute descriptor.
2824 */
2825int device_create_file(struct device *dev,
2826 const struct device_attribute *attr)
2827{
2828 int error = 0;
2829
2830 if (dev) {
2831 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
2832 "Attribute %s: write permission without 'store'\n",
2833 attr->attr.name);
2834 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
2835 "Attribute %s: read permission without 'show'\n",
2836 attr->attr.name);
2837 error = sysfs_create_file(&dev->kobj, &attr->attr);
2838 }
2839
2840 return error;
2841}
2842EXPORT_SYMBOL_GPL(device_create_file);
2843
2844/**
2845 * device_remove_file - remove sysfs attribute file.
2846 * @dev: device.
2847 * @attr: device attribute descriptor.
2848 */
2849void device_remove_file(struct device *dev,
2850 const struct device_attribute *attr)
2851{
2852 if (dev)
2853 sysfs_remove_file(&dev->kobj, &attr->attr);
2854}
2855EXPORT_SYMBOL_GPL(device_remove_file);
2856
2857/**
2858 * device_remove_file_self - remove sysfs attribute file from its own method.
2859 * @dev: device.
2860 * @attr: device attribute descriptor.
2861 *
2862 * See kernfs_remove_self() for details.
2863 */
2864bool device_remove_file_self(struct device *dev,
2865 const struct device_attribute *attr)
2866{
2867 if (dev)
2868 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
2869 else
2870 return false;
2871}
2872EXPORT_SYMBOL_GPL(device_remove_file_self);
2873
2874/**
2875 * device_create_bin_file - create sysfs binary attribute file for device.
2876 * @dev: device.
2877 * @attr: device binary attribute descriptor.
2878 */
2879int device_create_bin_file(struct device *dev,
2880 const struct bin_attribute *attr)
2881{
2882 int error = -EINVAL;
2883 if (dev)
2884 error = sysfs_create_bin_file(&dev->kobj, attr);
2885 return error;
2886}
2887EXPORT_SYMBOL_GPL(device_create_bin_file);
2888
2889/**
2890 * device_remove_bin_file - remove sysfs binary attribute file
2891 * @dev: device.
2892 * @attr: device binary attribute descriptor.
2893 */
2894void device_remove_bin_file(struct device *dev,
2895 const struct bin_attribute *attr)
2896{
2897 if (dev)
2898 sysfs_remove_bin_file(&dev->kobj, attr);
2899}
2900EXPORT_SYMBOL_GPL(device_remove_bin_file);
2901
2902static void klist_children_get(struct klist_node *n)
2903{
2904 struct device_private *p = to_device_private_parent(n);
2905 struct device *dev = p->device;
2906
2907 get_device(dev);
2908}
2909
2910static void klist_children_put(struct klist_node *n)
2911{
2912 struct device_private *p = to_device_private_parent(n);
2913 struct device *dev = p->device;
2914
2915 put_device(dev);
2916}
2917
2918/**
2919 * device_initialize - init device structure.
2920 * @dev: device.
2921 *
2922 * This prepares the device for use by other layers by initializing
2923 * its fields.
2924 * It is the first half of device_register(), if called by
2925 * that function, though it can also be called separately, so one
2926 * may use @dev's fields. In particular, get_device()/put_device()
2927 * may be used for reference counting of @dev after calling this
2928 * function.
2929 *
2930 * All fields in @dev must be initialized by the caller to 0, except
2931 * for those explicitly set to some other value. The simplest
2932 * approach is to use kzalloc() to allocate the structure containing
2933 * @dev.
2934 *
2935 * NOTE: Use put_device() to give up your reference instead of freeing
2936 * @dev directly once you have called this function.
2937 */
2938void device_initialize(struct device *dev)
2939{
2940 dev->kobj.kset = devices_kset;
2941 kobject_init(&dev->kobj, &device_ktype);
2942 INIT_LIST_HEAD(&dev->dma_pools);
2943 mutex_init(&dev->mutex);
2944 lockdep_set_novalidate_class(&dev->mutex);
2945 spin_lock_init(&dev->devres_lock);
2946 INIT_LIST_HEAD(&dev->devres_head);
2947 device_pm_init(dev);
2948 set_dev_node(dev, NUMA_NO_NODE);
2949 INIT_LIST_HEAD(&dev->links.consumers);
2950 INIT_LIST_HEAD(&dev->links.suppliers);
2951 INIT_LIST_HEAD(&dev->links.defer_sync);
2952 dev->links.status = DL_DEV_NO_DRIVER;
2953#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
2954 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
2955 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
2956 dev->dma_coherent = dma_default_coherent;
2957#endif
2958#ifdef CONFIG_SWIOTLB
2959 dev->dma_io_tlb_mem = &io_tlb_default_mem;
2960#endif
2961}
2962EXPORT_SYMBOL_GPL(device_initialize);
2963
2964struct kobject *virtual_device_parent(struct device *dev)
2965{
2966 static struct kobject *virtual_dir = NULL;
2967
2968 if (!virtual_dir)
2969 virtual_dir = kobject_create_and_add("virtual",
2970 &devices_kset->kobj);
2971
2972 return virtual_dir;
2973}
2974
2975struct class_dir {
2976 struct kobject kobj;
2977 struct class *class;
2978};
2979
2980#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
2981
2982static void class_dir_release(struct kobject *kobj)
2983{
2984 struct class_dir *dir = to_class_dir(kobj);
2985 kfree(dir);
2986}
2987
2988static const
2989struct kobj_ns_type_operations *class_dir_child_ns_type(const struct kobject *kobj)
2990{
2991 const struct class_dir *dir = to_class_dir(kobj);
2992 return dir->class->ns_type;
2993}
2994
2995static struct kobj_type class_dir_ktype = {
2996 .release = class_dir_release,
2997 .sysfs_ops = &kobj_sysfs_ops,
2998 .child_ns_type = class_dir_child_ns_type
2999};
3000
3001static struct kobject *
3002class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
3003{
3004 struct class_dir *dir;
3005 int retval;
3006
3007 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
3008 if (!dir)
3009 return ERR_PTR(-ENOMEM);
3010
3011 dir->class = class;
3012 kobject_init(&dir->kobj, &class_dir_ktype);
3013
3014 dir->kobj.kset = &class->p->glue_dirs;
3015
3016 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
3017 if (retval < 0) {
3018 kobject_put(&dir->kobj);
3019 return ERR_PTR(retval);
3020 }
3021 return &dir->kobj;
3022}
3023
3024static DEFINE_MUTEX(gdp_mutex);
3025
3026static struct kobject *get_device_parent(struct device *dev,
3027 struct device *parent)
3028{
3029 if (dev->class) {
3030 struct kobject *kobj = NULL;
3031 struct kobject *parent_kobj;
3032 struct kobject *k;
3033
3034#ifdef CONFIG_BLOCK
3035 /* block disks show up in /sys/block */
3036 if (sysfs_deprecated && dev->class == &block_class) {
3037 if (parent && parent->class == &block_class)
3038 return &parent->kobj;
3039 return &block_class.p->subsys.kobj;
3040 }
3041#endif
3042
3043 /*
3044 * If we have no parent, we live in "virtual".
3045 * Class-devices with a non class-device as parent, live
3046 * in a "glue" directory to prevent namespace collisions.
3047 */
3048 if (parent == NULL)
3049 parent_kobj = virtual_device_parent(dev);
3050 else if (parent->class && !dev->class->ns_type)
3051 return &parent->kobj;
3052 else
3053 parent_kobj = &parent->kobj;
3054
3055 mutex_lock(&gdp_mutex);
3056
3057 /* find our class-directory at the parent and reference it */
3058 spin_lock(&dev->class->p->glue_dirs.list_lock);
3059 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
3060 if (k->parent == parent_kobj) {
3061 kobj = kobject_get(k);
3062 break;
3063 }
3064 spin_unlock(&dev->class->p->glue_dirs.list_lock);
3065 if (kobj) {
3066 mutex_unlock(&gdp_mutex);
3067 return kobj;
3068 }
3069
3070 /* or create a new class-directory at the parent device */
3071 k = class_dir_create_and_add(dev->class, parent_kobj);
3072 /* do not emit an uevent for this simple "glue" directory */
3073 mutex_unlock(&gdp_mutex);
3074 return k;
3075 }
3076
3077 /* subsystems can specify a default root directory for their devices */
3078 if (!parent && dev->bus && dev->bus->dev_root)
3079 return &dev->bus->dev_root->kobj;
3080
3081 if (parent)
3082 return &parent->kobj;
3083 return NULL;
3084}
3085
3086static inline bool live_in_glue_dir(struct kobject *kobj,
3087 struct device *dev)
3088{
3089 if (!kobj || !dev->class ||
3090 kobj->kset != &dev->class->p->glue_dirs)
3091 return false;
3092 return true;
3093}
3094
3095static inline struct kobject *get_glue_dir(struct device *dev)
3096{
3097 return dev->kobj.parent;
3098}
3099
3100/**
3101 * kobject_has_children - Returns whether a kobject has children.
3102 * @kobj: the object to test
3103 *
3104 * This will return whether a kobject has other kobjects as children.
3105 *
3106 * It does NOT account for the presence of attribute files, only sub
3107 * directories. It also assumes there is no concurrent addition or
3108 * removal of such children, and thus relies on external locking.
3109 */
3110static inline bool kobject_has_children(struct kobject *kobj)
3111{
3112 WARN_ON_ONCE(kref_read(&kobj->kref) == 0);
3113
3114 return kobj->sd && kobj->sd->dir.subdirs;
3115}
3116
3117/*
3118 * make sure cleaning up dir as the last step, we need to make
3119 * sure .release handler of kobject is run with holding the
3120 * global lock
3121 */
3122static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
3123{
3124 unsigned int ref;
3125
3126 /* see if we live in a "glue" directory */
3127 if (!live_in_glue_dir(glue_dir, dev))
3128 return;
3129
3130 mutex_lock(&gdp_mutex);
3131 /**
3132 * There is a race condition between removing glue directory
3133 * and adding a new device under the glue directory.
3134 *
3135 * CPU1: CPU2:
3136 *
3137 * device_add()
3138 * get_device_parent()
3139 * class_dir_create_and_add()
3140 * kobject_add_internal()
3141 * create_dir() // create glue_dir
3142 *
3143 * device_add()
3144 * get_device_parent()
3145 * kobject_get() // get glue_dir
3146 *
3147 * device_del()
3148 * cleanup_glue_dir()
3149 * kobject_del(glue_dir)
3150 *
3151 * kobject_add()
3152 * kobject_add_internal()
3153 * create_dir() // in glue_dir
3154 * sysfs_create_dir_ns()
3155 * kernfs_create_dir_ns(sd)
3156 *
3157 * sysfs_remove_dir() // glue_dir->sd=NULL
3158 * sysfs_put() // free glue_dir->sd
3159 *
3160 * // sd is freed
3161 * kernfs_new_node(sd)
3162 * kernfs_get(glue_dir)
3163 * kernfs_add_one()
3164 * kernfs_put()
3165 *
3166 * Before CPU1 remove last child device under glue dir, if CPU2 add
3167 * a new device under glue dir, the glue_dir kobject reference count
3168 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3169 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3170 * and sysfs_put(). This result in glue_dir->sd is freed.
3171 *
3172 * Then the CPU2 will see a stale "empty" but still potentially used
3173 * glue dir around in kernfs_new_node().
3174 *
3175 * In order to avoid this happening, we also should make sure that
3176 * kernfs_node for glue_dir is released in CPU1 only when refcount
3177 * for glue_dir kobj is 1.
3178 */
3179 ref = kref_read(&glue_dir->kref);
3180 if (!kobject_has_children(glue_dir) && !--ref)
3181 kobject_del(glue_dir);
3182 kobject_put(glue_dir);
3183 mutex_unlock(&gdp_mutex);
3184}
3185
3186static int device_add_class_symlinks(struct device *dev)
3187{
3188 struct device_node *of_node = dev_of_node(dev);
3189 int error;
3190
3191 if (of_node) {
3192 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3193 if (error)
3194 dev_warn(dev, "Error %d creating of_node link\n",error);
3195 /* An error here doesn't warrant bringing down the device */
3196 }
3197
3198 if (!dev->class)
3199 return 0;
3200
3201 error = sysfs_create_link(&dev->kobj,
3202 &dev->class->p->subsys.kobj,
3203 "subsystem");
3204 if (error)
3205 goto out_devnode;
3206
3207 if (dev->parent && device_is_not_partition(dev)) {
3208 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3209 "device");
3210 if (error)
3211 goto out_subsys;
3212 }
3213
3214#ifdef CONFIG_BLOCK
3215 /* /sys/block has directories and does not need symlinks */
3216 if (sysfs_deprecated && dev->class == &block_class)
3217 return 0;
3218#endif
3219
3220 /* link in the class directory pointing to the device */
3221 error = sysfs_create_link(&dev->class->p->subsys.kobj,
3222 &dev->kobj, dev_name(dev));
3223 if (error)
3224 goto out_device;
3225
3226 return 0;
3227
3228out_device:
3229 sysfs_remove_link(&dev->kobj, "device");
3230
3231out_subsys:
3232 sysfs_remove_link(&dev->kobj, "subsystem");
3233out_devnode:
3234 sysfs_remove_link(&dev->kobj, "of_node");
3235 return error;
3236}
3237
3238static void device_remove_class_symlinks(struct device *dev)
3239{
3240 if (dev_of_node(dev))
3241 sysfs_remove_link(&dev->kobj, "of_node");
3242
3243 if (!dev->class)
3244 return;
3245
3246 if (dev->parent && device_is_not_partition(dev))
3247 sysfs_remove_link(&dev->kobj, "device");
3248 sysfs_remove_link(&dev->kobj, "subsystem");
3249#ifdef CONFIG_BLOCK
3250 if (sysfs_deprecated && dev->class == &block_class)
3251 return;
3252#endif
3253 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
3254}
3255
3256/**
3257 * dev_set_name - set a device name
3258 * @dev: device
3259 * @fmt: format string for the device's name
3260 */
3261int dev_set_name(struct device *dev, const char *fmt, ...)
3262{
3263 va_list vargs;
3264 int err;
3265
3266 va_start(vargs, fmt);
3267 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3268 va_end(vargs);
3269 return err;
3270}
3271EXPORT_SYMBOL_GPL(dev_set_name);
3272
3273/**
3274 * device_to_dev_kobj - select a /sys/dev/ directory for the device
3275 * @dev: device
3276 *
3277 * By default we select char/ for new entries. Setting class->dev_obj
3278 * to NULL prevents an entry from being created. class->dev_kobj must
3279 * be set (or cleared) before any devices are registered to the class
3280 * otherwise device_create_sys_dev_entry() and
3281 * device_remove_sys_dev_entry() will disagree about the presence of
3282 * the link.
3283 */
3284static struct kobject *device_to_dev_kobj(struct device *dev)
3285{
3286 struct kobject *kobj;
3287
3288 if (dev->class)
3289 kobj = dev->class->dev_kobj;
3290 else
3291 kobj = sysfs_dev_char_kobj;
3292
3293 return kobj;
3294}
3295
3296static int device_create_sys_dev_entry(struct device *dev)
3297{
3298 struct kobject *kobj = device_to_dev_kobj(dev);
3299 int error = 0;
3300 char devt_str[15];
3301
3302 if (kobj) {
3303 format_dev_t(devt_str, dev->devt);
3304 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3305 }
3306
3307 return error;
3308}
3309
3310static void device_remove_sys_dev_entry(struct device *dev)
3311{
3312 struct kobject *kobj = device_to_dev_kobj(dev);
3313 char devt_str[15];
3314
3315 if (kobj) {
3316 format_dev_t(devt_str, dev->devt);
3317 sysfs_remove_link(kobj, devt_str);
3318 }
3319}
3320
3321static int device_private_init(struct device *dev)
3322{
3323 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3324 if (!dev->p)
3325 return -ENOMEM;
3326 dev->p->device = dev;
3327 klist_init(&dev->p->klist_children, klist_children_get,
3328 klist_children_put);
3329 INIT_LIST_HEAD(&dev->p->deferred_probe);
3330 return 0;
3331}
3332
3333/**
3334 * device_add - add device to device hierarchy.
3335 * @dev: device.
3336 *
3337 * This is part 2 of device_register(), though may be called
3338 * separately _iff_ device_initialize() has been called separately.
3339 *
3340 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3341 * to the global and sibling lists for the device, then
3342 * adds it to the other relevant subsystems of the driver model.
3343 *
3344 * Do not call this routine or device_register() more than once for
3345 * any device structure. The driver model core is not designed to work
3346 * with devices that get unregistered and then spring back to life.
3347 * (Among other things, it's very hard to guarantee that all references
3348 * to the previous incarnation of @dev have been dropped.) Allocate
3349 * and register a fresh new struct device instead.
3350 *
3351 * NOTE: _Never_ directly free @dev after calling this function, even
3352 * if it returned an error! Always use put_device() to give up your
3353 * reference instead.
3354 *
3355 * Rule of thumb is: if device_add() succeeds, you should call
3356 * device_del() when you want to get rid of it. If device_add() has
3357 * *not* succeeded, use *only* put_device() to drop the reference
3358 * count.
3359 */
3360int device_add(struct device *dev)
3361{
3362 struct device *parent;
3363 struct kobject *kobj;
3364 struct class_interface *class_intf;
3365 int error = -EINVAL;
3366 struct kobject *glue_dir = NULL;
3367
3368 dev = get_device(dev);
3369 if (!dev)
3370 goto done;
3371
3372 if (!dev->p) {
3373 error = device_private_init(dev);
3374 if (error)
3375 goto done;
3376 }
3377
3378 /*
3379 * for statically allocated devices, which should all be converted
3380 * some day, we need to initialize the name. We prevent reading back
3381 * the name, and force the use of dev_name()
3382 */
3383 if (dev->init_name) {
3384 dev_set_name(dev, "%s", dev->init_name);
3385 dev->init_name = NULL;
3386 }
3387
3388 /* subsystems can specify simple device enumeration */
3389 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
3390 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3391
3392 if (!dev_name(dev)) {
3393 error = -EINVAL;
3394 goto name_error;
3395 }
3396
3397 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3398
3399 parent = get_device(dev->parent);
3400 kobj = get_device_parent(dev, parent);
3401 if (IS_ERR(kobj)) {
3402 error = PTR_ERR(kobj);
3403 goto parent_error;
3404 }
3405 if (kobj)
3406 dev->kobj.parent = kobj;
3407
3408 /* use parent numa_node */
3409 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3410 set_dev_node(dev, dev_to_node(parent));
3411
3412 /* first, register with generic layer. */
3413 /* we require the name to be set before, and pass NULL */
3414 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3415 if (error) {
3416 glue_dir = get_glue_dir(dev);
3417 goto Error;
3418 }
3419
3420 /* notify platform of device entry */
3421 device_platform_notify(dev);
3422
3423 error = device_create_file(dev, &dev_attr_uevent);
3424 if (error)
3425 goto attrError;
3426
3427 error = device_add_class_symlinks(dev);
3428 if (error)
3429 goto SymlinkError;
3430 error = device_add_attrs(dev);
3431 if (error)
3432 goto AttrsError;
3433 error = bus_add_device(dev);
3434 if (error)
3435 goto BusError;
3436 error = dpm_sysfs_add(dev);
3437 if (error)
3438 goto DPMError;
3439 device_pm_add(dev);
3440
3441 if (MAJOR(dev->devt)) {
3442 error = device_create_file(dev, &dev_attr_dev);
3443 if (error)
3444 goto DevAttrError;
3445
3446 error = device_create_sys_dev_entry(dev);
3447 if (error)
3448 goto SysEntryError;
3449
3450 devtmpfs_create_node(dev);
3451 }
3452
3453 /* Notify clients of device addition. This call must come
3454 * after dpm_sysfs_add() and before kobject_uevent().
3455 */
3456 if (dev->bus)
3457 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3458 BUS_NOTIFY_ADD_DEVICE, dev);
3459
3460 kobject_uevent(&dev->kobj, KOBJ_ADD);
3461
3462 /*
3463 * Check if any of the other devices (consumers) have been waiting for
3464 * this device (supplier) to be added so that they can create a device
3465 * link to it.
3466 *
3467 * This needs to happen after device_pm_add() because device_link_add()
3468 * requires the supplier be registered before it's called.
3469 *
3470 * But this also needs to happen before bus_probe_device() to make sure
3471 * waiting consumers can link to it before the driver is bound to the
3472 * device and the driver sync_state callback is called for this device.
3473 */
3474 if (dev->fwnode && !dev->fwnode->dev) {
3475 dev->fwnode->dev = dev;
3476 fw_devlink_link_device(dev);
3477 }
3478
3479 bus_probe_device(dev);
3480
3481 /*
3482 * If all driver registration is done and a newly added device doesn't
3483 * match with any driver, don't block its consumers from probing in
3484 * case the consumer device is able to operate without this supplier.
3485 */
3486 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3487 fw_devlink_unblock_consumers(dev);
3488
3489 if (parent)
3490 klist_add_tail(&dev->p->knode_parent,
3491 &parent->p->klist_children);
3492
3493 if (dev->class) {
3494 mutex_lock(&dev->class->p->mutex);
3495 /* tie the class to the device */
3496 klist_add_tail(&dev->p->knode_class,
3497 &dev->class->p->klist_devices);
3498
3499 /* notify any interfaces that the device is here */
3500 list_for_each_entry(class_intf,
3501 &dev->class->p->interfaces, node)
3502 if (class_intf->add_dev)
3503 class_intf->add_dev(dev, class_intf);
3504 mutex_unlock(&dev->class->p->mutex);
3505 }
3506done:
3507 put_device(dev);
3508 return error;
3509 SysEntryError:
3510 if (MAJOR(dev->devt))
3511 device_remove_file(dev, &dev_attr_dev);
3512 DevAttrError:
3513 device_pm_remove(dev);
3514 dpm_sysfs_remove(dev);
3515 DPMError:
3516 bus_remove_device(dev);
3517 BusError:
3518 device_remove_attrs(dev);
3519 AttrsError:
3520 device_remove_class_symlinks(dev);
3521 SymlinkError:
3522 device_remove_file(dev, &dev_attr_uevent);
3523 attrError:
3524 device_platform_notify_remove(dev);
3525 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3526 glue_dir = get_glue_dir(dev);
3527 kobject_del(&dev->kobj);
3528 Error:
3529 cleanup_glue_dir(dev, glue_dir);
3530parent_error:
3531 put_device(parent);
3532name_error:
3533 kfree(dev->p);
3534 dev->p = NULL;
3535 goto done;
3536}
3537EXPORT_SYMBOL_GPL(device_add);
3538
3539/**
3540 * device_register - register a device with the system.
3541 * @dev: pointer to the device structure
3542 *
3543 * This happens in two clean steps - initialize the device
3544 * and add it to the system. The two steps can be called
3545 * separately, but this is the easiest and most common.
3546 * I.e. you should only call the two helpers separately if
3547 * have a clearly defined need to use and refcount the device
3548 * before it is added to the hierarchy.
3549 *
3550 * For more information, see the kerneldoc for device_initialize()
3551 * and device_add().
3552 *
3553 * NOTE: _Never_ directly free @dev after calling this function, even
3554 * if it returned an error! Always use put_device() to give up the
3555 * reference initialized in this function instead.
3556 */
3557int device_register(struct device *dev)
3558{
3559 device_initialize(dev);
3560 return device_add(dev);
3561}
3562EXPORT_SYMBOL_GPL(device_register);
3563
3564/**
3565 * get_device - increment reference count for device.
3566 * @dev: device.
3567 *
3568 * This simply forwards the call to kobject_get(), though
3569 * we do take care to provide for the case that we get a NULL
3570 * pointer passed in.
3571 */
3572struct device *get_device(struct device *dev)
3573{
3574 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3575}
3576EXPORT_SYMBOL_GPL(get_device);
3577
3578/**
3579 * put_device - decrement reference count.
3580 * @dev: device in question.
3581 */
3582void put_device(struct device *dev)
3583{
3584 /* might_sleep(); */
3585 if (dev)
3586 kobject_put(&dev->kobj);
3587}
3588EXPORT_SYMBOL_GPL(put_device);
3589
3590bool kill_device(struct device *dev)
3591{
3592 /*
3593 * Require the device lock and set the "dead" flag to guarantee that
3594 * the update behavior is consistent with the other bitfields near
3595 * it and that we cannot have an asynchronous probe routine trying
3596 * to run while we are tearing out the bus/class/sysfs from
3597 * underneath the device.
3598 */
3599 device_lock_assert(dev);
3600
3601 if (dev->p->dead)
3602 return false;
3603 dev->p->dead = true;
3604 return true;
3605}
3606EXPORT_SYMBOL_GPL(kill_device);
3607
3608/**
3609 * device_del - delete device from system.
3610 * @dev: device.
3611 *
3612 * This is the first part of the device unregistration
3613 * sequence. This removes the device from the lists we control
3614 * from here, has it removed from the other driver model
3615 * subsystems it was added to in device_add(), and removes it
3616 * from the kobject hierarchy.
3617 *
3618 * NOTE: this should be called manually _iff_ device_add() was
3619 * also called manually.
3620 */
3621void device_del(struct device *dev)
3622{
3623 struct device *parent = dev->parent;
3624 struct kobject *glue_dir = NULL;
3625 struct class_interface *class_intf;
3626 unsigned int noio_flag;
3627
3628 device_lock(dev);
3629 kill_device(dev);
3630 device_unlock(dev);
3631
3632 if (dev->fwnode && dev->fwnode->dev == dev)
3633 dev->fwnode->dev = NULL;
3634
3635 /* Notify clients of device removal. This call must come
3636 * before dpm_sysfs_remove().
3637 */
3638 noio_flag = memalloc_noio_save();
3639 if (dev->bus)
3640 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3641 BUS_NOTIFY_DEL_DEVICE, dev);
3642
3643 dpm_sysfs_remove(dev);
3644 if (parent)
3645 klist_del(&dev->p->knode_parent);
3646 if (MAJOR(dev->devt)) {
3647 devtmpfs_delete_node(dev);
3648 device_remove_sys_dev_entry(dev);
3649 device_remove_file(dev, &dev_attr_dev);
3650 }
3651 if (dev->class) {
3652 device_remove_class_symlinks(dev);
3653
3654 mutex_lock(&dev->class->p->mutex);
3655 /* notify any interfaces that the device is now gone */
3656 list_for_each_entry(class_intf,
3657 &dev->class->p->interfaces, node)
3658 if (class_intf->remove_dev)
3659 class_intf->remove_dev(dev, class_intf);
3660 /* remove the device from the class list */
3661 klist_del(&dev->p->knode_class);
3662 mutex_unlock(&dev->class->p->mutex);
3663 }
3664 device_remove_file(dev, &dev_attr_uevent);
3665 device_remove_attrs(dev);
3666 bus_remove_device(dev);
3667 device_pm_remove(dev);
3668 driver_deferred_probe_del(dev);
3669 device_platform_notify_remove(dev);
3670 device_links_purge(dev);
3671
3672 if (dev->bus)
3673 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3674 BUS_NOTIFY_REMOVED_DEVICE, dev);
3675 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3676 glue_dir = get_glue_dir(dev);
3677 kobject_del(&dev->kobj);
3678 cleanup_glue_dir(dev, glue_dir);
3679 memalloc_noio_restore(noio_flag);
3680 put_device(parent);
3681}
3682EXPORT_SYMBOL_GPL(device_del);
3683
3684/**
3685 * device_unregister - unregister device from system.
3686 * @dev: device going away.
3687 *
3688 * We do this in two parts, like we do device_register(). First,
3689 * we remove it from all the subsystems with device_del(), then
3690 * we decrement the reference count via put_device(). If that
3691 * is the final reference count, the device will be cleaned up
3692 * via device_release() above. Otherwise, the structure will
3693 * stick around until the final reference to the device is dropped.
3694 */
3695void device_unregister(struct device *dev)
3696{
3697 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3698 device_del(dev);
3699 put_device(dev);
3700}
3701EXPORT_SYMBOL_GPL(device_unregister);
3702
3703static struct device *prev_device(struct klist_iter *i)
3704{
3705 struct klist_node *n = klist_prev(i);
3706 struct device *dev = NULL;
3707 struct device_private *p;
3708
3709 if (n) {
3710 p = to_device_private_parent(n);
3711 dev = p->device;
3712 }
3713 return dev;
3714}
3715
3716static struct device *next_device(struct klist_iter *i)
3717{
3718 struct klist_node *n = klist_next(i);
3719 struct device *dev = NULL;
3720 struct device_private *p;
3721
3722 if (n) {
3723 p = to_device_private_parent(n);
3724 dev = p->device;
3725 }
3726 return dev;
3727}
3728
3729/**
3730 * device_get_devnode - path of device node file
3731 * @dev: device
3732 * @mode: returned file access mode
3733 * @uid: returned file owner
3734 * @gid: returned file group
3735 * @tmp: possibly allocated string
3736 *
3737 * Return the relative path of a possible device node.
3738 * Non-default names may need to allocate a memory to compose
3739 * a name. This memory is returned in tmp and needs to be
3740 * freed by the caller.
3741 */
3742const char *device_get_devnode(struct device *dev,
3743 umode_t *mode, kuid_t *uid, kgid_t *gid,
3744 const char **tmp)
3745{
3746 char *s;
3747
3748 *tmp = NULL;
3749
3750 /* the device type may provide a specific name */
3751 if (dev->type && dev->type->devnode)
3752 *tmp = dev->type->devnode(dev, mode, uid, gid);
3753 if (*tmp)
3754 return *tmp;
3755
3756 /* the class may provide a specific name */
3757 if (dev->class && dev->class->devnode)
3758 *tmp = dev->class->devnode(dev, mode);
3759 if (*tmp)
3760 return *tmp;
3761
3762 /* return name without allocation, tmp == NULL */
3763 if (strchr(dev_name(dev), '!') == NULL)
3764 return dev_name(dev);
3765
3766 /* replace '!' in the name with '/' */
3767 s = kstrdup(dev_name(dev), GFP_KERNEL);
3768 if (!s)
3769 return NULL;
3770 strreplace(s, '!', '/');
3771 return *tmp = s;
3772}
3773
3774/**
3775 * device_for_each_child - device child iterator.
3776 * @parent: parent struct device.
3777 * @fn: function to be called for each device.
3778 * @data: data for the callback.
3779 *
3780 * Iterate over @parent's child devices, and call @fn for each,
3781 * passing it @data.
3782 *
3783 * We check the return of @fn each time. If it returns anything
3784 * other than 0, we break out and return that value.
3785 */
3786int device_for_each_child(struct device *parent, void *data,
3787 int (*fn)(struct device *dev, void *data))
3788{
3789 struct klist_iter i;
3790 struct device *child;
3791 int error = 0;
3792
3793 if (!parent->p)
3794 return 0;
3795
3796 klist_iter_init(&parent->p->klist_children, &i);
3797 while (!error && (child = next_device(&i)))
3798 error = fn(child, data);
3799 klist_iter_exit(&i);
3800 return error;
3801}
3802EXPORT_SYMBOL_GPL(device_for_each_child);
3803
3804/**
3805 * device_for_each_child_reverse - device child iterator in reversed order.
3806 * @parent: parent struct device.
3807 * @fn: function to be called for each device.
3808 * @data: data for the callback.
3809 *
3810 * Iterate over @parent's child devices, and call @fn for each,
3811 * passing it @data.
3812 *
3813 * We check the return of @fn each time. If it returns anything
3814 * other than 0, we break out and return that value.
3815 */
3816int device_for_each_child_reverse(struct device *parent, void *data,
3817 int (*fn)(struct device *dev, void *data))
3818{
3819 struct klist_iter i;
3820 struct device *child;
3821 int error = 0;
3822
3823 if (!parent->p)
3824 return 0;
3825
3826 klist_iter_init(&parent->p->klist_children, &i);
3827 while ((child = prev_device(&i)) && !error)
3828 error = fn(child, data);
3829 klist_iter_exit(&i);
3830 return error;
3831}
3832EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
3833
3834/**
3835 * device_find_child - device iterator for locating a particular device.
3836 * @parent: parent struct device
3837 * @match: Callback function to check device
3838 * @data: Data to pass to match function
3839 *
3840 * This is similar to the device_for_each_child() function above, but it
3841 * returns a reference to a device that is 'found' for later use, as
3842 * determined by the @match callback.
3843 *
3844 * The callback should return 0 if the device doesn't match and non-zero
3845 * if it does. If the callback returns non-zero and a reference to the
3846 * current device can be obtained, this function will return to the caller
3847 * and not iterate over any more devices.
3848 *
3849 * NOTE: you will need to drop the reference with put_device() after use.
3850 */
3851struct device *device_find_child(struct device *parent, void *data,
3852 int (*match)(struct device *dev, void *data))
3853{
3854 struct klist_iter i;
3855 struct device *child;
3856
3857 if (!parent)
3858 return NULL;
3859
3860 klist_iter_init(&parent->p->klist_children, &i);
3861 while ((child = next_device(&i)))
3862 if (match(child, data) && get_device(child))
3863 break;
3864 klist_iter_exit(&i);
3865 return child;
3866}
3867EXPORT_SYMBOL_GPL(device_find_child);
3868
3869/**
3870 * device_find_child_by_name - device iterator for locating a child device.
3871 * @parent: parent struct device
3872 * @name: name of the child device
3873 *
3874 * This is similar to the device_find_child() function above, but it
3875 * returns a reference to a device that has the name @name.
3876 *
3877 * NOTE: you will need to drop the reference with put_device() after use.
3878 */
3879struct device *device_find_child_by_name(struct device *parent,
3880 const char *name)
3881{
3882 struct klist_iter i;
3883 struct device *child;
3884
3885 if (!parent)
3886 return NULL;
3887
3888 klist_iter_init(&parent->p->klist_children, &i);
3889 while ((child = next_device(&i)))
3890 if (sysfs_streq(dev_name(child), name) && get_device(child))
3891 break;
3892 klist_iter_exit(&i);
3893 return child;
3894}
3895EXPORT_SYMBOL_GPL(device_find_child_by_name);
3896
3897static int match_any(struct device *dev, void *unused)
3898{
3899 return 1;
3900}
3901
3902/**
3903 * device_find_any_child - device iterator for locating a child device, if any.
3904 * @parent: parent struct device
3905 *
3906 * This is similar to the device_find_child() function above, but it
3907 * returns a reference to a child device, if any.
3908 *
3909 * NOTE: you will need to drop the reference with put_device() after use.
3910 */
3911struct device *device_find_any_child(struct device *parent)
3912{
3913 return device_find_child(parent, NULL, match_any);
3914}
3915EXPORT_SYMBOL_GPL(device_find_any_child);
3916
3917int __init devices_init(void)
3918{
3919 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
3920 if (!devices_kset)
3921 return -ENOMEM;
3922 dev_kobj = kobject_create_and_add("dev", NULL);
3923 if (!dev_kobj)
3924 goto dev_kobj_err;
3925 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
3926 if (!sysfs_dev_block_kobj)
3927 goto block_kobj_err;
3928 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
3929 if (!sysfs_dev_char_kobj)
3930 goto char_kobj_err;
3931
3932 return 0;
3933
3934 char_kobj_err:
3935 kobject_put(sysfs_dev_block_kobj);
3936 block_kobj_err:
3937 kobject_put(dev_kobj);
3938 dev_kobj_err:
3939 kset_unregister(devices_kset);
3940 return -ENOMEM;
3941}
3942
3943static int device_check_offline(struct device *dev, void *not_used)
3944{
3945 int ret;
3946
3947 ret = device_for_each_child(dev, NULL, device_check_offline);
3948 if (ret)
3949 return ret;
3950
3951 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
3952}
3953
3954/**
3955 * device_offline - Prepare the device for hot-removal.
3956 * @dev: Device to be put offline.
3957 *
3958 * Execute the device bus type's .offline() callback, if present, to prepare
3959 * the device for a subsequent hot-removal. If that succeeds, the device must
3960 * not be used until either it is removed or its bus type's .online() callback
3961 * is executed.
3962 *
3963 * Call under device_hotplug_lock.
3964 */
3965int device_offline(struct device *dev)
3966{
3967 int ret;
3968
3969 if (dev->offline_disabled)
3970 return -EPERM;
3971
3972 ret = device_for_each_child(dev, NULL, device_check_offline);
3973 if (ret)
3974 return ret;
3975
3976 device_lock(dev);
3977 if (device_supports_offline(dev)) {
3978 if (dev->offline) {
3979 ret = 1;
3980 } else {
3981 ret = dev->bus->offline(dev);
3982 if (!ret) {
3983 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
3984 dev->offline = true;
3985 }
3986 }
3987 }
3988 device_unlock(dev);
3989
3990 return ret;
3991}
3992
3993/**
3994 * device_online - Put the device back online after successful device_offline().
3995 * @dev: Device to be put back online.
3996 *
3997 * If device_offline() has been successfully executed for @dev, but the device
3998 * has not been removed subsequently, execute its bus type's .online() callback
3999 * to indicate that the device can be used again.
4000 *
4001 * Call under device_hotplug_lock.
4002 */
4003int device_online(struct device *dev)
4004{
4005 int ret = 0;
4006
4007 device_lock(dev);
4008 if (device_supports_offline(dev)) {
4009 if (dev->offline) {
4010 ret = dev->bus->online(dev);
4011 if (!ret) {
4012 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
4013 dev->offline = false;
4014 }
4015 } else {
4016 ret = 1;
4017 }
4018 }
4019 device_unlock(dev);
4020
4021 return ret;
4022}
4023
4024struct root_device {
4025 struct device dev;
4026 struct module *owner;
4027};
4028
4029static inline struct root_device *to_root_device(struct device *d)
4030{
4031 return container_of(d, struct root_device, dev);
4032}
4033
4034static void root_device_release(struct device *dev)
4035{
4036 kfree(to_root_device(dev));
4037}
4038
4039/**
4040 * __root_device_register - allocate and register a root device
4041 * @name: root device name
4042 * @owner: owner module of the root device, usually THIS_MODULE
4043 *
4044 * This function allocates a root device and registers it
4045 * using device_register(). In order to free the returned
4046 * device, use root_device_unregister().
4047 *
4048 * Root devices are dummy devices which allow other devices
4049 * to be grouped under /sys/devices. Use this function to
4050 * allocate a root device and then use it as the parent of
4051 * any device which should appear under /sys/devices/{name}
4052 *
4053 * The /sys/devices/{name} directory will also contain a
4054 * 'module' symlink which points to the @owner directory
4055 * in sysfs.
4056 *
4057 * Returns &struct device pointer on success, or ERR_PTR() on error.
4058 *
4059 * Note: You probably want to use root_device_register().
4060 */
4061struct device *__root_device_register(const char *name, struct module *owner)
4062{
4063 struct root_device *root;
4064 int err = -ENOMEM;
4065
4066 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
4067 if (!root)
4068 return ERR_PTR(err);
4069
4070 err = dev_set_name(&root->dev, "%s", name);
4071 if (err) {
4072 kfree(root);
4073 return ERR_PTR(err);
4074 }
4075
4076 root->dev.release = root_device_release;
4077
4078 err = device_register(&root->dev);
4079 if (err) {
4080 put_device(&root->dev);
4081 return ERR_PTR(err);
4082 }
4083
4084#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
4085 if (owner) {
4086 struct module_kobject *mk = &owner->mkobj;
4087
4088 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
4089 if (err) {
4090 device_unregister(&root->dev);
4091 return ERR_PTR(err);
4092 }
4093 root->owner = owner;
4094 }
4095#endif
4096
4097 return &root->dev;
4098}
4099EXPORT_SYMBOL_GPL(__root_device_register);
4100
4101/**
4102 * root_device_unregister - unregister and free a root device
4103 * @dev: device going away
4104 *
4105 * This function unregisters and cleans up a device that was created by
4106 * root_device_register().
4107 */
4108void root_device_unregister(struct device *dev)
4109{
4110 struct root_device *root = to_root_device(dev);
4111
4112 if (root->owner)
4113 sysfs_remove_link(&root->dev.kobj, "module");
4114
4115 device_unregister(dev);
4116}
4117EXPORT_SYMBOL_GPL(root_device_unregister);
4118
4119
4120static void device_create_release(struct device *dev)
4121{
4122 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
4123 kfree(dev);
4124}
4125
4126static __printf(6, 0) struct device *
4127device_create_groups_vargs(struct class *class, struct device *parent,
4128 dev_t devt, void *drvdata,
4129 const struct attribute_group **groups,
4130 const char *fmt, va_list args)
4131{
4132 struct device *dev = NULL;
4133 int retval = -ENODEV;
4134
4135 if (IS_ERR_OR_NULL(class))
4136 goto error;
4137
4138 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4139 if (!dev) {
4140 retval = -ENOMEM;
4141 goto error;
4142 }
4143
4144 device_initialize(dev);
4145 dev->devt = devt;
4146 dev->class = class;
4147 dev->parent = parent;
4148 dev->groups = groups;
4149 dev->release = device_create_release;
4150 dev_set_drvdata(dev, drvdata);
4151
4152 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
4153 if (retval)
4154 goto error;
4155
4156 retval = device_add(dev);
4157 if (retval)
4158 goto error;
4159
4160 return dev;
4161
4162error:
4163 put_device(dev);
4164 return ERR_PTR(retval);
4165}
4166
4167/**
4168 * device_create - creates a device and registers it with sysfs
4169 * @class: pointer to the struct class that this device should be registered to
4170 * @parent: pointer to the parent struct device of this new device, if any
4171 * @devt: the dev_t for the char device to be added
4172 * @drvdata: the data to be added to the device for callbacks
4173 * @fmt: string for the device's name
4174 *
4175 * This function can be used by char device classes. A struct device
4176 * will be created in sysfs, registered to the specified class.
4177 *
4178 * A "dev" file will be created, showing the dev_t for the device, if
4179 * the dev_t is not 0,0.
4180 * If a pointer to a parent struct device is passed in, the newly created
4181 * struct device will be a child of that device in sysfs.
4182 * The pointer to the struct device will be returned from the call.
4183 * Any further sysfs files that might be required can be created using this
4184 * pointer.
4185 *
4186 * Returns &struct device pointer on success, or ERR_PTR() on error.
4187 *
4188 * Note: the struct class passed to this function must have previously
4189 * been created with a call to class_create().
4190 */
4191struct device *device_create(struct class *class, struct device *parent,
4192 dev_t devt, void *drvdata, const char *fmt, ...)
4193{
4194 va_list vargs;
4195 struct device *dev;
4196
4197 va_start(vargs, fmt);
4198 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4199 fmt, vargs);
4200 va_end(vargs);
4201 return dev;
4202}
4203EXPORT_SYMBOL_GPL(device_create);
4204
4205/**
4206 * device_create_with_groups - creates a device and registers it with sysfs
4207 * @class: pointer to the struct class that this device should be registered to
4208 * @parent: pointer to the parent struct device of this new device, if any
4209 * @devt: the dev_t for the char device to be added
4210 * @drvdata: the data to be added to the device for callbacks
4211 * @groups: NULL-terminated list of attribute groups to be created
4212 * @fmt: string for the device's name
4213 *
4214 * This function can be used by char device classes. A struct device
4215 * will be created in sysfs, registered to the specified class.
4216 * Additional attributes specified in the groups parameter will also
4217 * be created automatically.
4218 *
4219 * A "dev" file will be created, showing the dev_t for the device, if
4220 * the dev_t is not 0,0.
4221 * If a pointer to a parent struct device is passed in, the newly created
4222 * struct device will be a child of that device in sysfs.
4223 * The pointer to the struct device will be returned from the call.
4224 * Any further sysfs files that might be required can be created using this
4225 * pointer.
4226 *
4227 * Returns &struct device pointer on success, or ERR_PTR() on error.
4228 *
4229 * Note: the struct class passed to this function must have previously
4230 * been created with a call to class_create().
4231 */
4232struct device *device_create_with_groups(struct class *class,
4233 struct device *parent, dev_t devt,
4234 void *drvdata,
4235 const struct attribute_group **groups,
4236 const char *fmt, ...)
4237{
4238 va_list vargs;
4239 struct device *dev;
4240
4241 va_start(vargs, fmt);
4242 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4243 fmt, vargs);
4244 va_end(vargs);
4245 return dev;
4246}
4247EXPORT_SYMBOL_GPL(device_create_with_groups);
4248
4249/**
4250 * device_destroy - removes a device that was created with device_create()
4251 * @class: pointer to the struct class that this device was registered with
4252 * @devt: the dev_t of the device that was previously registered
4253 *
4254 * This call unregisters and cleans up a device that was created with a
4255 * call to device_create().
4256 */
4257void device_destroy(struct class *class, dev_t devt)
4258{
4259 struct device *dev;
4260
4261 dev = class_find_device_by_devt(class, devt);
4262 if (dev) {
4263 put_device(dev);
4264 device_unregister(dev);
4265 }
4266}
4267EXPORT_SYMBOL_GPL(device_destroy);
4268
4269/**
4270 * device_rename - renames a device
4271 * @dev: the pointer to the struct device to be renamed
4272 * @new_name: the new name of the device
4273 *
4274 * It is the responsibility of the caller to provide mutual
4275 * exclusion between two different calls of device_rename
4276 * on the same device to ensure that new_name is valid and
4277 * won't conflict with other devices.
4278 *
4279 * Note: Don't call this function. Currently, the networking layer calls this
4280 * function, but that will change. The following text from Kay Sievers offers
4281 * some insight:
4282 *
4283 * Renaming devices is racy at many levels, symlinks and other stuff are not
4284 * replaced atomically, and you get a "move" uevent, but it's not easy to
4285 * connect the event to the old and new device. Device nodes are not renamed at
4286 * all, there isn't even support for that in the kernel now.
4287 *
4288 * In the meantime, during renaming, your target name might be taken by another
4289 * driver, creating conflicts. Or the old name is taken directly after you
4290 * renamed it -- then you get events for the same DEVPATH, before you even see
4291 * the "move" event. It's just a mess, and nothing new should ever rely on
4292 * kernel device renaming. Besides that, it's not even implemented now for
4293 * other things than (driver-core wise very simple) network devices.
4294 *
4295 * We are currently about to change network renaming in udev to completely
4296 * disallow renaming of devices in the same namespace as the kernel uses,
4297 * because we can't solve the problems properly, that arise with swapping names
4298 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
4299 * be allowed to some other name than eth[0-9]*, for the aforementioned
4300 * reasons.
4301 *
4302 * Make up a "real" name in the driver before you register anything, or add
4303 * some other attributes for userspace to find the device, or use udev to add
4304 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4305 * don't even want to get into that and try to implement the missing pieces in
4306 * the core. We really have other pieces to fix in the driver core mess. :)
4307 */
4308int device_rename(struct device *dev, const char *new_name)
4309{
4310 struct kobject *kobj = &dev->kobj;
4311 char *old_device_name = NULL;
4312 int error;
4313
4314 dev = get_device(dev);
4315 if (!dev)
4316 return -EINVAL;
4317
4318 dev_dbg(dev, "renaming to %s\n", new_name);
4319
4320 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4321 if (!old_device_name) {
4322 error = -ENOMEM;
4323 goto out;
4324 }
4325
4326 if (dev->class) {
4327 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
4328 kobj, old_device_name,
4329 new_name, kobject_namespace(kobj));
4330 if (error)
4331 goto out;
4332 }
4333
4334 error = kobject_rename(kobj, new_name);
4335 if (error)
4336 goto out;
4337
4338out:
4339 put_device(dev);
4340
4341 kfree(old_device_name);
4342
4343 return error;
4344}
4345EXPORT_SYMBOL_GPL(device_rename);
4346
4347static int device_move_class_links(struct device *dev,
4348 struct device *old_parent,
4349 struct device *new_parent)
4350{
4351 int error = 0;
4352
4353 if (old_parent)
4354 sysfs_remove_link(&dev->kobj, "device");
4355 if (new_parent)
4356 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4357 "device");
4358 return error;
4359}
4360
4361/**
4362 * device_move - moves a device to a new parent
4363 * @dev: the pointer to the struct device to be moved
4364 * @new_parent: the new parent of the device (can be NULL)
4365 * @dpm_order: how to reorder the dpm_list
4366 */
4367int device_move(struct device *dev, struct device *new_parent,
4368 enum dpm_order dpm_order)
4369{
4370 int error;
4371 struct device *old_parent;
4372 struct kobject *new_parent_kobj;
4373
4374 dev = get_device(dev);
4375 if (!dev)
4376 return -EINVAL;
4377
4378 device_pm_lock();
4379 new_parent = get_device(new_parent);
4380 new_parent_kobj = get_device_parent(dev, new_parent);
4381 if (IS_ERR(new_parent_kobj)) {
4382 error = PTR_ERR(new_parent_kobj);
4383 put_device(new_parent);
4384 goto out;
4385 }
4386
4387 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4388 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4389 error = kobject_move(&dev->kobj, new_parent_kobj);
4390 if (error) {
4391 cleanup_glue_dir(dev, new_parent_kobj);
4392 put_device(new_parent);
4393 goto out;
4394 }
4395 old_parent = dev->parent;
4396 dev->parent = new_parent;
4397 if (old_parent)
4398 klist_remove(&dev->p->knode_parent);
4399 if (new_parent) {
4400 klist_add_tail(&dev->p->knode_parent,
4401 &new_parent->p->klist_children);
4402 set_dev_node(dev, dev_to_node(new_parent));
4403 }
4404
4405 if (dev->class) {
4406 error = device_move_class_links(dev, old_parent, new_parent);
4407 if (error) {
4408 /* We ignore errors on cleanup since we're hosed anyway... */
4409 device_move_class_links(dev, new_parent, old_parent);
4410 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4411 if (new_parent)
4412 klist_remove(&dev->p->knode_parent);
4413 dev->parent = old_parent;
4414 if (old_parent) {
4415 klist_add_tail(&dev->p->knode_parent,
4416 &old_parent->p->klist_children);
4417 set_dev_node(dev, dev_to_node(old_parent));
4418 }
4419 }
4420 cleanup_glue_dir(dev, new_parent_kobj);
4421 put_device(new_parent);
4422 goto out;
4423 }
4424 }
4425 switch (dpm_order) {
4426 case DPM_ORDER_NONE:
4427 break;
4428 case DPM_ORDER_DEV_AFTER_PARENT:
4429 device_pm_move_after(dev, new_parent);
4430 devices_kset_move_after(dev, new_parent);
4431 break;
4432 case DPM_ORDER_PARENT_BEFORE_DEV:
4433 device_pm_move_before(new_parent, dev);
4434 devices_kset_move_before(new_parent, dev);
4435 break;
4436 case DPM_ORDER_DEV_LAST:
4437 device_pm_move_last(dev);
4438 devices_kset_move_last(dev);
4439 break;
4440 }
4441
4442 put_device(old_parent);
4443out:
4444 device_pm_unlock();
4445 put_device(dev);
4446 return error;
4447}
4448EXPORT_SYMBOL_GPL(device_move);
4449
4450static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4451 kgid_t kgid)
4452{
4453 struct kobject *kobj = &dev->kobj;
4454 struct class *class = dev->class;
4455 const struct device_type *type = dev->type;
4456 int error;
4457
4458 if (class) {
4459 /*
4460 * Change the device groups of the device class for @dev to
4461 * @kuid/@kgid.
4462 */
4463 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4464 kgid);
4465 if (error)
4466 return error;
4467 }
4468
4469 if (type) {
4470 /*
4471 * Change the device groups of the device type for @dev to
4472 * @kuid/@kgid.
4473 */
4474 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4475 kgid);
4476 if (error)
4477 return error;
4478 }
4479
4480 /* Change the device groups of @dev to @kuid/@kgid. */
4481 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4482 if (error)
4483 return error;
4484
4485 if (device_supports_offline(dev) && !dev->offline_disabled) {
4486 /* Change online device attributes of @dev to @kuid/@kgid. */
4487 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4488 kuid, kgid);
4489 if (error)
4490 return error;
4491 }
4492
4493 return 0;
4494}
4495
4496/**
4497 * device_change_owner - change the owner of an existing device.
4498 * @dev: device.
4499 * @kuid: new owner's kuid
4500 * @kgid: new owner's kgid
4501 *
4502 * This changes the owner of @dev and its corresponding sysfs entries to
4503 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4504 * core.
4505 *
4506 * Returns 0 on success or error code on failure.
4507 */
4508int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4509{
4510 int error;
4511 struct kobject *kobj = &dev->kobj;
4512
4513 dev = get_device(dev);
4514 if (!dev)
4515 return -EINVAL;
4516
4517 /*
4518 * Change the kobject and the default attributes and groups of the
4519 * ktype associated with it to @kuid/@kgid.
4520 */
4521 error = sysfs_change_owner(kobj, kuid, kgid);
4522 if (error)
4523 goto out;
4524
4525 /*
4526 * Change the uevent file for @dev to the new owner. The uevent file
4527 * was created in a separate step when @dev got added and we mirror
4528 * that step here.
4529 */
4530 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4531 kgid);
4532 if (error)
4533 goto out;
4534
4535 /*
4536 * Change the device groups, the device groups associated with the
4537 * device class, and the groups associated with the device type of @dev
4538 * to @kuid/@kgid.
4539 */
4540 error = device_attrs_change_owner(dev, kuid, kgid);
4541 if (error)
4542 goto out;
4543
4544 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4545 if (error)
4546 goto out;
4547
4548#ifdef CONFIG_BLOCK
4549 if (sysfs_deprecated && dev->class == &block_class)
4550 goto out;
4551#endif
4552
4553 /*
4554 * Change the owner of the symlink located in the class directory of
4555 * the device class associated with @dev which points to the actual
4556 * directory entry for @dev to @kuid/@kgid. This ensures that the
4557 * symlink shows the same permissions as its target.
4558 */
4559 error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj,
4560 dev_name(dev), kuid, kgid);
4561 if (error)
4562 goto out;
4563
4564out:
4565 put_device(dev);
4566 return error;
4567}
4568EXPORT_SYMBOL_GPL(device_change_owner);
4569
4570/**
4571 * device_shutdown - call ->shutdown() on each device to shutdown.
4572 */
4573void device_shutdown(void)
4574{
4575 struct device *dev, *parent;
4576
4577 wait_for_device_probe();
4578 device_block_probing();
4579
4580 cpufreq_suspend();
4581
4582 spin_lock(&devices_kset->list_lock);
4583 /*
4584 * Walk the devices list backward, shutting down each in turn.
4585 * Beware that device unplug events may also start pulling
4586 * devices offline, even as the system is shutting down.
4587 */
4588 while (!list_empty(&devices_kset->list)) {
4589 dev = list_entry(devices_kset->list.prev, struct device,
4590 kobj.entry);
4591
4592 /*
4593 * hold reference count of device's parent to
4594 * prevent it from being freed because parent's
4595 * lock is to be held
4596 */
4597 parent = get_device(dev->parent);
4598 get_device(dev);
4599 /*
4600 * Make sure the device is off the kset list, in the
4601 * event that dev->*->shutdown() doesn't remove it.
4602 */
4603 list_del_init(&dev->kobj.entry);
4604 spin_unlock(&devices_kset->list_lock);
4605
4606 /* hold lock to avoid race with probe/release */
4607 if (parent)
4608 device_lock(parent);
4609 device_lock(dev);
4610
4611 /* Don't allow any more runtime suspends */
4612 pm_runtime_get_noresume(dev);
4613 pm_runtime_barrier(dev);
4614
4615 if (dev->class && dev->class->shutdown_pre) {
4616 if (initcall_debug)
4617 dev_info(dev, "shutdown_pre\n");
4618 dev->class->shutdown_pre(dev);
4619 }
4620 if (dev->bus && dev->bus->shutdown) {
4621 if (initcall_debug)
4622 dev_info(dev, "shutdown\n");
4623 dev->bus->shutdown(dev);
4624 } else if (dev->driver && dev->driver->shutdown) {
4625 if (initcall_debug)
4626 dev_info(dev, "shutdown\n");
4627 dev->driver->shutdown(dev);
4628 }
4629
4630 device_unlock(dev);
4631 if (parent)
4632 device_unlock(parent);
4633
4634 put_device(dev);
4635 put_device(parent);
4636
4637 spin_lock(&devices_kset->list_lock);
4638 }
4639 spin_unlock(&devices_kset->list_lock);
4640}
4641
4642/*
4643 * Device logging functions
4644 */
4645
4646#ifdef CONFIG_PRINTK
4647static void
4648set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4649{
4650 const char *subsys;
4651
4652 memset(dev_info, 0, sizeof(*dev_info));
4653
4654 if (dev->class)
4655 subsys = dev->class->name;
4656 else if (dev->bus)
4657 subsys = dev->bus->name;
4658 else
4659 return;
4660
4661 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
4662
4663 /*
4664 * Add device identifier DEVICE=:
4665 * b12:8 block dev_t
4666 * c127:3 char dev_t
4667 * n8 netdev ifindex
4668 * +sound:card0 subsystem:devname
4669 */
4670 if (MAJOR(dev->devt)) {
4671 char c;
4672
4673 if (strcmp(subsys, "block") == 0)
4674 c = 'b';
4675 else
4676 c = 'c';
4677
4678 snprintf(dev_info->device, sizeof(dev_info->device),
4679 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4680 } else if (strcmp(subsys, "net") == 0) {
4681 struct net_device *net = to_net_dev(dev);
4682
4683 snprintf(dev_info->device, sizeof(dev_info->device),
4684 "n%u", net->ifindex);
4685 } else {
4686 snprintf(dev_info->device, sizeof(dev_info->device),
4687 "+%s:%s", subsys, dev_name(dev));
4688 }
4689}
4690
4691int dev_vprintk_emit(int level, const struct device *dev,
4692 const char *fmt, va_list args)
4693{
4694 struct dev_printk_info dev_info;
4695
4696 set_dev_info(dev, &dev_info);
4697
4698 return vprintk_emit(0, level, &dev_info, fmt, args);
4699}
4700EXPORT_SYMBOL(dev_vprintk_emit);
4701
4702int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4703{
4704 va_list args;
4705 int r;
4706
4707 va_start(args, fmt);
4708
4709 r = dev_vprintk_emit(level, dev, fmt, args);
4710
4711 va_end(args);
4712
4713 return r;
4714}
4715EXPORT_SYMBOL(dev_printk_emit);
4716
4717static void __dev_printk(const char *level, const struct device *dev,
4718 struct va_format *vaf)
4719{
4720 if (dev)
4721 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4722 dev_driver_string(dev), dev_name(dev), vaf);
4723 else
4724 printk("%s(NULL device *): %pV", level, vaf);
4725}
4726
4727void _dev_printk(const char *level, const struct device *dev,
4728 const char *fmt, ...)
4729{
4730 struct va_format vaf;
4731 va_list args;
4732
4733 va_start(args, fmt);
4734
4735 vaf.fmt = fmt;
4736 vaf.va = &args;
4737
4738 __dev_printk(level, dev, &vaf);
4739
4740 va_end(args);
4741}
4742EXPORT_SYMBOL(_dev_printk);
4743
4744#define define_dev_printk_level(func, kern_level) \
4745void func(const struct device *dev, const char *fmt, ...) \
4746{ \
4747 struct va_format vaf; \
4748 va_list args; \
4749 \
4750 va_start(args, fmt); \
4751 \
4752 vaf.fmt = fmt; \
4753 vaf.va = &args; \
4754 \
4755 __dev_printk(kern_level, dev, &vaf); \
4756 \
4757 va_end(args); \
4758} \
4759EXPORT_SYMBOL(func);
4760
4761define_dev_printk_level(_dev_emerg, KERN_EMERG);
4762define_dev_printk_level(_dev_alert, KERN_ALERT);
4763define_dev_printk_level(_dev_crit, KERN_CRIT);
4764define_dev_printk_level(_dev_err, KERN_ERR);
4765define_dev_printk_level(_dev_warn, KERN_WARNING);
4766define_dev_printk_level(_dev_notice, KERN_NOTICE);
4767define_dev_printk_level(_dev_info, KERN_INFO);
4768
4769#endif
4770
4771/**
4772 * dev_err_probe - probe error check and log helper
4773 * @dev: the pointer to the struct device
4774 * @err: error value to test
4775 * @fmt: printf-style format string
4776 * @...: arguments as specified in the format string
4777 *
4778 * This helper implements common pattern present in probe functions for error
4779 * checking: print debug or error message depending if the error value is
4780 * -EPROBE_DEFER and propagate error upwards.
4781 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4782 * checked later by reading devices_deferred debugfs attribute.
4783 * It replaces code sequence::
4784 *
4785 * if (err != -EPROBE_DEFER)
4786 * dev_err(dev, ...);
4787 * else
4788 * dev_dbg(dev, ...);
4789 * return err;
4790 *
4791 * with::
4792 *
4793 * return dev_err_probe(dev, err, ...);
4794 *
4795 * Note that it is deemed acceptable to use this function for error
4796 * prints during probe even if the @err is known to never be -EPROBE_DEFER.
4797 * The benefit compared to a normal dev_err() is the standardized format
4798 * of the error code and the fact that the error code is returned.
4799 *
4800 * Returns @err.
4801 *
4802 */
4803int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4804{
4805 struct va_format vaf;
4806 va_list args;
4807
4808 va_start(args, fmt);
4809 vaf.fmt = fmt;
4810 vaf.va = &args;
4811
4812 if (err != -EPROBE_DEFER) {
4813 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4814 } else {
4815 device_set_deferred_probe_reason(dev, &vaf);
4816 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4817 }
4818
4819 va_end(args);
4820
4821 return err;
4822}
4823EXPORT_SYMBOL_GPL(dev_err_probe);
4824
4825static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4826{
4827 return fwnode && !IS_ERR(fwnode->secondary);
4828}
4829
4830/**
4831 * set_primary_fwnode - Change the primary firmware node of a given device.
4832 * @dev: Device to handle.
4833 * @fwnode: New primary firmware node of the device.
4834 *
4835 * Set the device's firmware node pointer to @fwnode, but if a secondary
4836 * firmware node of the device is present, preserve it.
4837 *
4838 * Valid fwnode cases are:
4839 * - primary --> secondary --> -ENODEV
4840 * - primary --> NULL
4841 * - secondary --> -ENODEV
4842 * - NULL
4843 */
4844void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4845{
4846 struct device *parent = dev->parent;
4847 struct fwnode_handle *fn = dev->fwnode;
4848
4849 if (fwnode) {
4850 if (fwnode_is_primary(fn))
4851 fn = fn->secondary;
4852
4853 if (fn) {
4854 WARN_ON(fwnode->secondary);
4855 fwnode->secondary = fn;
4856 }
4857 dev->fwnode = fwnode;
4858 } else {
4859 if (fwnode_is_primary(fn)) {
4860 dev->fwnode = fn->secondary;
4861 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
4862 if (!(parent && fn == parent->fwnode))
4863 fn->secondary = NULL;
4864 } else {
4865 dev->fwnode = NULL;
4866 }
4867 }
4868}
4869EXPORT_SYMBOL_GPL(set_primary_fwnode);
4870
4871/**
4872 * set_secondary_fwnode - Change the secondary firmware node of a given device.
4873 * @dev: Device to handle.
4874 * @fwnode: New secondary firmware node of the device.
4875 *
4876 * If a primary firmware node of the device is present, set its secondary
4877 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
4878 * @fwnode.
4879 */
4880void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4881{
4882 if (fwnode)
4883 fwnode->secondary = ERR_PTR(-ENODEV);
4884
4885 if (fwnode_is_primary(dev->fwnode))
4886 dev->fwnode->secondary = fwnode;
4887 else
4888 dev->fwnode = fwnode;
4889}
4890EXPORT_SYMBOL_GPL(set_secondary_fwnode);
4891
4892/**
4893 * device_set_of_node_from_dev - reuse device-tree node of another device
4894 * @dev: device whose device-tree node is being set
4895 * @dev2: device whose device-tree node is being reused
4896 *
4897 * Takes another reference to the new device-tree node after first dropping
4898 * any reference held to the old node.
4899 */
4900void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
4901{
4902 of_node_put(dev->of_node);
4903 dev->of_node = of_node_get(dev2->of_node);
4904 dev->of_node_reused = true;
4905}
4906EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
4907
4908void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
4909{
4910 dev->fwnode = fwnode;
4911 dev->of_node = to_of_node(fwnode);
4912}
4913EXPORT_SYMBOL_GPL(device_set_node);
4914
4915int device_match_name(struct device *dev, const void *name)
4916{
4917 return sysfs_streq(dev_name(dev), name);
4918}
4919EXPORT_SYMBOL_GPL(device_match_name);
4920
4921int device_match_of_node(struct device *dev, const void *np)
4922{
4923 return dev->of_node == np;
4924}
4925EXPORT_SYMBOL_GPL(device_match_of_node);
4926
4927int device_match_fwnode(struct device *dev, const void *fwnode)
4928{
4929 return dev_fwnode(dev) == fwnode;
4930}
4931EXPORT_SYMBOL_GPL(device_match_fwnode);
4932
4933int device_match_devt(struct device *dev, const void *pdevt)
4934{
4935 return dev->devt == *(dev_t *)pdevt;
4936}
4937EXPORT_SYMBOL_GPL(device_match_devt);
4938
4939int device_match_acpi_dev(struct device *dev, const void *adev)
4940{
4941 return ACPI_COMPANION(dev) == adev;
4942}
4943EXPORT_SYMBOL(device_match_acpi_dev);
4944
4945int device_match_acpi_handle(struct device *dev, const void *handle)
4946{
4947 return ACPI_HANDLE(dev) == handle;
4948}
4949EXPORT_SYMBOL(device_match_acpi_handle);
4950
4951int device_match_any(struct device *dev, const void *unused)
4952{
4953 return 1;
4954}
4955EXPORT_SYMBOL_GPL(device_match_any);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * drivers/base/core.c - core driver model code (device registration, etc)
4 *
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
7 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
8 * Copyright (c) 2006 Novell, Inc.
9 */
10
11#include <linux/acpi.h>
12#include <linux/cpufreq.h>
13#include <linux/device.h>
14#include <linux/err.h>
15#include <linux/fwnode.h>
16#include <linux/init.h>
17#include <linux/module.h>
18#include <linux/slab.h>
19#include <linux/string.h>
20#include <linux/kdev_t.h>
21#include <linux/notifier.h>
22#include <linux/of.h>
23#include <linux/of_device.h>
24#include <linux/genhd.h>
25#include <linux/mutex.h>
26#include <linux/pm_runtime.h>
27#include <linux/netdevice.h>
28#include <linux/sched/signal.h>
29#include <linux/sched/mm.h>
30#include <linux/sysfs.h>
31#include <linux/dma-map-ops.h> /* for dma_default_coherent */
32
33#include "base.h"
34#include "power/power.h"
35
36#ifdef CONFIG_SYSFS_DEPRECATED
37#ifdef CONFIG_SYSFS_DEPRECATED_V2
38long sysfs_deprecated = 1;
39#else
40long sysfs_deprecated = 0;
41#endif
42static int __init sysfs_deprecated_setup(char *arg)
43{
44 return kstrtol(arg, 10, &sysfs_deprecated);
45}
46early_param("sysfs.deprecated", sysfs_deprecated_setup);
47#endif
48
49/* Device links support. */
50static LIST_HEAD(deferred_sync);
51static unsigned int defer_sync_state_count = 1;
52static DEFINE_MUTEX(fwnode_link_lock);
53static bool fw_devlink_is_permissive(void);
54static bool fw_devlink_drv_reg_done;
55
56/**
57 * fwnode_link_add - Create a link between two fwnode_handles.
58 * @con: Consumer end of the link.
59 * @sup: Supplier end of the link.
60 *
61 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
62 * represents the detail that the firmware lists @sup fwnode as supplying a
63 * resource to @con.
64 *
65 * The driver core will use the fwnode link to create a device link between the
66 * two device objects corresponding to @con and @sup when they are created. The
67 * driver core will automatically delete the fwnode link between @con and @sup
68 * after doing that.
69 *
70 * Attempts to create duplicate links between the same pair of fwnode handles
71 * are ignored and there is no reference counting.
72 */
73int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
74{
75 struct fwnode_link *link;
76 int ret = 0;
77
78 mutex_lock(&fwnode_link_lock);
79
80 list_for_each_entry(link, &sup->consumers, s_hook)
81 if (link->consumer == con)
82 goto out;
83
84 link = kzalloc(sizeof(*link), GFP_KERNEL);
85 if (!link) {
86 ret = -ENOMEM;
87 goto out;
88 }
89
90 link->supplier = sup;
91 INIT_LIST_HEAD(&link->s_hook);
92 link->consumer = con;
93 INIT_LIST_HEAD(&link->c_hook);
94
95 list_add(&link->s_hook, &sup->consumers);
96 list_add(&link->c_hook, &con->suppliers);
97out:
98 mutex_unlock(&fwnode_link_lock);
99
100 return ret;
101}
102
103/**
104 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
105 * @fwnode: fwnode whose supplier links need to be deleted
106 *
107 * Deletes all supplier links connecting directly to @fwnode.
108 */
109static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
110{
111 struct fwnode_link *link, *tmp;
112
113 mutex_lock(&fwnode_link_lock);
114 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
115 list_del(&link->s_hook);
116 list_del(&link->c_hook);
117 kfree(link);
118 }
119 mutex_unlock(&fwnode_link_lock);
120}
121
122/**
123 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
124 * @fwnode: fwnode whose consumer links need to be deleted
125 *
126 * Deletes all consumer links connecting directly to @fwnode.
127 */
128static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
129{
130 struct fwnode_link *link, *tmp;
131
132 mutex_lock(&fwnode_link_lock);
133 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
134 list_del(&link->s_hook);
135 list_del(&link->c_hook);
136 kfree(link);
137 }
138 mutex_unlock(&fwnode_link_lock);
139}
140
141/**
142 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
143 * @fwnode: fwnode whose links needs to be deleted
144 *
145 * Deletes all links connecting directly to a fwnode.
146 */
147void fwnode_links_purge(struct fwnode_handle *fwnode)
148{
149 fwnode_links_purge_suppliers(fwnode);
150 fwnode_links_purge_consumers(fwnode);
151}
152
153void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
154{
155 struct fwnode_handle *child;
156
157 /* Don't purge consumer links of an added child */
158 if (fwnode->dev)
159 return;
160
161 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
162 fwnode_links_purge_consumers(fwnode);
163
164 fwnode_for_each_available_child_node(fwnode, child)
165 fw_devlink_purge_absent_suppliers(child);
166}
167EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
168
169#ifdef CONFIG_SRCU
170static DEFINE_MUTEX(device_links_lock);
171DEFINE_STATIC_SRCU(device_links_srcu);
172
173static inline void device_links_write_lock(void)
174{
175 mutex_lock(&device_links_lock);
176}
177
178static inline void device_links_write_unlock(void)
179{
180 mutex_unlock(&device_links_lock);
181}
182
183int device_links_read_lock(void) __acquires(&device_links_srcu)
184{
185 return srcu_read_lock(&device_links_srcu);
186}
187
188void device_links_read_unlock(int idx) __releases(&device_links_srcu)
189{
190 srcu_read_unlock(&device_links_srcu, idx);
191}
192
193int device_links_read_lock_held(void)
194{
195 return srcu_read_lock_held(&device_links_srcu);
196}
197
198static void device_link_synchronize_removal(void)
199{
200 synchronize_srcu(&device_links_srcu);
201}
202
203static void device_link_remove_from_lists(struct device_link *link)
204{
205 list_del_rcu(&link->s_node);
206 list_del_rcu(&link->c_node);
207}
208#else /* !CONFIG_SRCU */
209static DECLARE_RWSEM(device_links_lock);
210
211static inline void device_links_write_lock(void)
212{
213 down_write(&device_links_lock);
214}
215
216static inline void device_links_write_unlock(void)
217{
218 up_write(&device_links_lock);
219}
220
221int device_links_read_lock(void)
222{
223 down_read(&device_links_lock);
224 return 0;
225}
226
227void device_links_read_unlock(int not_used)
228{
229 up_read(&device_links_lock);
230}
231
232#ifdef CONFIG_DEBUG_LOCK_ALLOC
233int device_links_read_lock_held(void)
234{
235 return lockdep_is_held(&device_links_lock);
236}
237#endif
238
239static inline void device_link_synchronize_removal(void)
240{
241}
242
243static void device_link_remove_from_lists(struct device_link *link)
244{
245 list_del(&link->s_node);
246 list_del(&link->c_node);
247}
248#endif /* !CONFIG_SRCU */
249
250static bool device_is_ancestor(struct device *dev, struct device *target)
251{
252 while (target->parent) {
253 target = target->parent;
254 if (dev == target)
255 return true;
256 }
257 return false;
258}
259
260/**
261 * device_is_dependent - Check if one device depends on another one
262 * @dev: Device to check dependencies for.
263 * @target: Device to check against.
264 *
265 * Check if @target depends on @dev or any device dependent on it (its child or
266 * its consumer etc). Return 1 if that is the case or 0 otherwise.
267 */
268int device_is_dependent(struct device *dev, void *target)
269{
270 struct device_link *link;
271 int ret;
272
273 /*
274 * The "ancestors" check is needed to catch the case when the target
275 * device has not been completely initialized yet and it is still
276 * missing from the list of children of its parent device.
277 */
278 if (dev == target || device_is_ancestor(dev, target))
279 return 1;
280
281 ret = device_for_each_child(dev, target, device_is_dependent);
282 if (ret)
283 return ret;
284
285 list_for_each_entry(link, &dev->links.consumers, s_node) {
286 if ((link->flags & ~DL_FLAG_INFERRED) ==
287 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
288 continue;
289
290 if (link->consumer == target)
291 return 1;
292
293 ret = device_is_dependent(link->consumer, target);
294 if (ret)
295 break;
296 }
297 return ret;
298}
299
300static void device_link_init_status(struct device_link *link,
301 struct device *consumer,
302 struct device *supplier)
303{
304 switch (supplier->links.status) {
305 case DL_DEV_PROBING:
306 switch (consumer->links.status) {
307 case DL_DEV_PROBING:
308 /*
309 * A consumer driver can create a link to a supplier
310 * that has not completed its probing yet as long as it
311 * knows that the supplier is already functional (for
312 * example, it has just acquired some resources from the
313 * supplier).
314 */
315 link->status = DL_STATE_CONSUMER_PROBE;
316 break;
317 default:
318 link->status = DL_STATE_DORMANT;
319 break;
320 }
321 break;
322 case DL_DEV_DRIVER_BOUND:
323 switch (consumer->links.status) {
324 case DL_DEV_PROBING:
325 link->status = DL_STATE_CONSUMER_PROBE;
326 break;
327 case DL_DEV_DRIVER_BOUND:
328 link->status = DL_STATE_ACTIVE;
329 break;
330 default:
331 link->status = DL_STATE_AVAILABLE;
332 break;
333 }
334 break;
335 case DL_DEV_UNBINDING:
336 link->status = DL_STATE_SUPPLIER_UNBIND;
337 break;
338 default:
339 link->status = DL_STATE_DORMANT;
340 break;
341 }
342}
343
344static int device_reorder_to_tail(struct device *dev, void *not_used)
345{
346 struct device_link *link;
347
348 /*
349 * Devices that have not been registered yet will be put to the ends
350 * of the lists during the registration, so skip them here.
351 */
352 if (device_is_registered(dev))
353 devices_kset_move_last(dev);
354
355 if (device_pm_initialized(dev))
356 device_pm_move_last(dev);
357
358 device_for_each_child(dev, NULL, device_reorder_to_tail);
359 list_for_each_entry(link, &dev->links.consumers, s_node) {
360 if ((link->flags & ~DL_FLAG_INFERRED) ==
361 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
362 continue;
363 device_reorder_to_tail(link->consumer, NULL);
364 }
365
366 return 0;
367}
368
369/**
370 * device_pm_move_to_tail - Move set of devices to the end of device lists
371 * @dev: Device to move
372 *
373 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
374 *
375 * It moves the @dev along with all of its children and all of its consumers
376 * to the ends of the device_kset and dpm_list, recursively.
377 */
378void device_pm_move_to_tail(struct device *dev)
379{
380 int idx;
381
382 idx = device_links_read_lock();
383 device_pm_lock();
384 device_reorder_to_tail(dev, NULL);
385 device_pm_unlock();
386 device_links_read_unlock(idx);
387}
388
389#define to_devlink(dev) container_of((dev), struct device_link, link_dev)
390
391static ssize_t status_show(struct device *dev,
392 struct device_attribute *attr, char *buf)
393{
394 const char *output;
395
396 switch (to_devlink(dev)->status) {
397 case DL_STATE_NONE:
398 output = "not tracked";
399 break;
400 case DL_STATE_DORMANT:
401 output = "dormant";
402 break;
403 case DL_STATE_AVAILABLE:
404 output = "available";
405 break;
406 case DL_STATE_CONSUMER_PROBE:
407 output = "consumer probing";
408 break;
409 case DL_STATE_ACTIVE:
410 output = "active";
411 break;
412 case DL_STATE_SUPPLIER_UNBIND:
413 output = "supplier unbinding";
414 break;
415 default:
416 output = "unknown";
417 break;
418 }
419
420 return sysfs_emit(buf, "%s\n", output);
421}
422static DEVICE_ATTR_RO(status);
423
424static ssize_t auto_remove_on_show(struct device *dev,
425 struct device_attribute *attr, char *buf)
426{
427 struct device_link *link = to_devlink(dev);
428 const char *output;
429
430 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
431 output = "supplier unbind";
432 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
433 output = "consumer unbind";
434 else
435 output = "never";
436
437 return sysfs_emit(buf, "%s\n", output);
438}
439static DEVICE_ATTR_RO(auto_remove_on);
440
441static ssize_t runtime_pm_show(struct device *dev,
442 struct device_attribute *attr, char *buf)
443{
444 struct device_link *link = to_devlink(dev);
445
446 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
447}
448static DEVICE_ATTR_RO(runtime_pm);
449
450static ssize_t sync_state_only_show(struct device *dev,
451 struct device_attribute *attr, char *buf)
452{
453 struct device_link *link = to_devlink(dev);
454
455 return sysfs_emit(buf, "%d\n",
456 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
457}
458static DEVICE_ATTR_RO(sync_state_only);
459
460static struct attribute *devlink_attrs[] = {
461 &dev_attr_status.attr,
462 &dev_attr_auto_remove_on.attr,
463 &dev_attr_runtime_pm.attr,
464 &dev_attr_sync_state_only.attr,
465 NULL,
466};
467ATTRIBUTE_GROUPS(devlink);
468
469static void device_link_release_fn(struct work_struct *work)
470{
471 struct device_link *link = container_of(work, struct device_link, rm_work);
472
473 /* Ensure that all references to the link object have been dropped. */
474 device_link_synchronize_removal();
475
476 while (refcount_dec_not_one(&link->rpm_active))
477 pm_runtime_put(link->supplier);
478
479 put_device(link->consumer);
480 put_device(link->supplier);
481 kfree(link);
482}
483
484static void devlink_dev_release(struct device *dev)
485{
486 struct device_link *link = to_devlink(dev);
487
488 INIT_WORK(&link->rm_work, device_link_release_fn);
489 /*
490 * It may take a while to complete this work because of the SRCU
491 * synchronization in device_link_release_fn() and if the consumer or
492 * supplier devices get deleted when it runs, so put it into the "long"
493 * workqueue.
494 */
495 queue_work(system_long_wq, &link->rm_work);
496}
497
498static struct class devlink_class = {
499 .name = "devlink",
500 .owner = THIS_MODULE,
501 .dev_groups = devlink_groups,
502 .dev_release = devlink_dev_release,
503};
504
505static int devlink_add_symlinks(struct device *dev,
506 struct class_interface *class_intf)
507{
508 int ret;
509 size_t len;
510 struct device_link *link = to_devlink(dev);
511 struct device *sup = link->supplier;
512 struct device *con = link->consumer;
513 char *buf;
514
515 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
516 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
517 len += strlen(":");
518 len += strlen("supplier:") + 1;
519 buf = kzalloc(len, GFP_KERNEL);
520 if (!buf)
521 return -ENOMEM;
522
523 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
524 if (ret)
525 goto out;
526
527 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
528 if (ret)
529 goto err_con;
530
531 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
532 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
533 if (ret)
534 goto err_con_dev;
535
536 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
537 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
538 if (ret)
539 goto err_sup_dev;
540
541 goto out;
542
543err_sup_dev:
544 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
545 sysfs_remove_link(&sup->kobj, buf);
546err_con_dev:
547 sysfs_remove_link(&link->link_dev.kobj, "consumer");
548err_con:
549 sysfs_remove_link(&link->link_dev.kobj, "supplier");
550out:
551 kfree(buf);
552 return ret;
553}
554
555static void devlink_remove_symlinks(struct device *dev,
556 struct class_interface *class_intf)
557{
558 struct device_link *link = to_devlink(dev);
559 size_t len;
560 struct device *sup = link->supplier;
561 struct device *con = link->consumer;
562 char *buf;
563
564 sysfs_remove_link(&link->link_dev.kobj, "consumer");
565 sysfs_remove_link(&link->link_dev.kobj, "supplier");
566
567 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
568 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
569 len += strlen(":");
570 len += strlen("supplier:") + 1;
571 buf = kzalloc(len, GFP_KERNEL);
572 if (!buf) {
573 WARN(1, "Unable to properly free device link symlinks!\n");
574 return;
575 }
576
577 if (device_is_registered(con)) {
578 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
579 sysfs_remove_link(&con->kobj, buf);
580 }
581 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
582 sysfs_remove_link(&sup->kobj, buf);
583 kfree(buf);
584}
585
586static struct class_interface devlink_class_intf = {
587 .class = &devlink_class,
588 .add_dev = devlink_add_symlinks,
589 .remove_dev = devlink_remove_symlinks,
590};
591
592static int __init devlink_class_init(void)
593{
594 int ret;
595
596 ret = class_register(&devlink_class);
597 if (ret)
598 return ret;
599
600 ret = class_interface_register(&devlink_class_intf);
601 if (ret)
602 class_unregister(&devlink_class);
603
604 return ret;
605}
606postcore_initcall(devlink_class_init);
607
608#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
609 DL_FLAG_AUTOREMOVE_SUPPLIER | \
610 DL_FLAG_AUTOPROBE_CONSUMER | \
611 DL_FLAG_SYNC_STATE_ONLY | \
612 DL_FLAG_INFERRED)
613
614#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
615 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
616
617/**
618 * device_link_add - Create a link between two devices.
619 * @consumer: Consumer end of the link.
620 * @supplier: Supplier end of the link.
621 * @flags: Link flags.
622 *
623 * The caller is responsible for the proper synchronization of the link creation
624 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
625 * runtime PM framework to take the link into account. Second, if the
626 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
627 * be forced into the active meta state and reference-counted upon the creation
628 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
629 * ignored.
630 *
631 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
632 * expected to release the link returned by it directly with the help of either
633 * device_link_del() or device_link_remove().
634 *
635 * If that flag is not set, however, the caller of this function is handing the
636 * management of the link over to the driver core entirely and its return value
637 * can only be used to check whether or not the link is present. In that case,
638 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
639 * flags can be used to indicate to the driver core when the link can be safely
640 * deleted. Namely, setting one of them in @flags indicates to the driver core
641 * that the link is not going to be used (by the given caller of this function)
642 * after unbinding the consumer or supplier driver, respectively, from its
643 * device, so the link can be deleted at that point. If none of them is set,
644 * the link will be maintained until one of the devices pointed to by it (either
645 * the consumer or the supplier) is unregistered.
646 *
647 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
648 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
649 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
650 * be used to request the driver core to automatically probe for a consumer
651 * driver after successfully binding a driver to the supplier device.
652 *
653 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
654 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
655 * the same time is invalid and will cause NULL to be returned upfront.
656 * However, if a device link between the given @consumer and @supplier pair
657 * exists already when this function is called for them, the existing link will
658 * be returned regardless of its current type and status (the link's flags may
659 * be modified then). The caller of this function is then expected to treat
660 * the link as though it has just been created, so (in particular) if
661 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
662 * explicitly when not needed any more (as stated above).
663 *
664 * A side effect of the link creation is re-ordering of dpm_list and the
665 * devices_kset list by moving the consumer device and all devices depending
666 * on it to the ends of these lists (that does not happen to devices that have
667 * not been registered when this function is called).
668 *
669 * The supplier device is required to be registered when this function is called
670 * and NULL will be returned if that is not the case. The consumer device need
671 * not be registered, however.
672 */
673struct device_link *device_link_add(struct device *consumer,
674 struct device *supplier, u32 flags)
675{
676 struct device_link *link;
677
678 if (!consumer || !supplier || consumer == supplier ||
679 flags & ~DL_ADD_VALID_FLAGS ||
680 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
681 (flags & DL_FLAG_SYNC_STATE_ONLY &&
682 (flags & ~DL_FLAG_INFERRED) != DL_FLAG_SYNC_STATE_ONLY) ||
683 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
684 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
685 DL_FLAG_AUTOREMOVE_SUPPLIER)))
686 return NULL;
687
688 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
689 if (pm_runtime_get_sync(supplier) < 0) {
690 pm_runtime_put_noidle(supplier);
691 return NULL;
692 }
693 }
694
695 if (!(flags & DL_FLAG_STATELESS))
696 flags |= DL_FLAG_MANAGED;
697
698 device_links_write_lock();
699 device_pm_lock();
700
701 /*
702 * If the supplier has not been fully registered yet or there is a
703 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
704 * the supplier already in the graph, return NULL. If the link is a
705 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
706 * because it only affects sync_state() callbacks.
707 */
708 if (!device_pm_initialized(supplier)
709 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
710 device_is_dependent(consumer, supplier))) {
711 link = NULL;
712 goto out;
713 }
714
715 /*
716 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
717 * So, only create it if the consumer hasn't probed yet.
718 */
719 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
720 consumer->links.status != DL_DEV_NO_DRIVER &&
721 consumer->links.status != DL_DEV_PROBING) {
722 link = NULL;
723 goto out;
724 }
725
726 /*
727 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
728 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
729 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
730 */
731 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
732 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
733
734 list_for_each_entry(link, &supplier->links.consumers, s_node) {
735 if (link->consumer != consumer)
736 continue;
737
738 if (link->flags & DL_FLAG_INFERRED &&
739 !(flags & DL_FLAG_INFERRED))
740 link->flags &= ~DL_FLAG_INFERRED;
741
742 if (flags & DL_FLAG_PM_RUNTIME) {
743 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
744 pm_runtime_new_link(consumer);
745 link->flags |= DL_FLAG_PM_RUNTIME;
746 }
747 if (flags & DL_FLAG_RPM_ACTIVE)
748 refcount_inc(&link->rpm_active);
749 }
750
751 if (flags & DL_FLAG_STATELESS) {
752 kref_get(&link->kref);
753 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
754 !(link->flags & DL_FLAG_STATELESS)) {
755 link->flags |= DL_FLAG_STATELESS;
756 goto reorder;
757 } else {
758 link->flags |= DL_FLAG_STATELESS;
759 goto out;
760 }
761 }
762
763 /*
764 * If the life time of the link following from the new flags is
765 * longer than indicated by the flags of the existing link,
766 * update the existing link to stay around longer.
767 */
768 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
769 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
770 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
771 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
772 }
773 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
774 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
775 DL_FLAG_AUTOREMOVE_SUPPLIER);
776 }
777 if (!(link->flags & DL_FLAG_MANAGED)) {
778 kref_get(&link->kref);
779 link->flags |= DL_FLAG_MANAGED;
780 device_link_init_status(link, consumer, supplier);
781 }
782 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
783 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
784 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
785 goto reorder;
786 }
787
788 goto out;
789 }
790
791 link = kzalloc(sizeof(*link), GFP_KERNEL);
792 if (!link)
793 goto out;
794
795 refcount_set(&link->rpm_active, 1);
796
797 get_device(supplier);
798 link->supplier = supplier;
799 INIT_LIST_HEAD(&link->s_node);
800 get_device(consumer);
801 link->consumer = consumer;
802 INIT_LIST_HEAD(&link->c_node);
803 link->flags = flags;
804 kref_init(&link->kref);
805
806 link->link_dev.class = &devlink_class;
807 device_set_pm_not_required(&link->link_dev);
808 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
809 dev_bus_name(supplier), dev_name(supplier),
810 dev_bus_name(consumer), dev_name(consumer));
811 if (device_register(&link->link_dev)) {
812 put_device(consumer);
813 put_device(supplier);
814 kfree(link);
815 link = NULL;
816 goto out;
817 }
818
819 if (flags & DL_FLAG_PM_RUNTIME) {
820 if (flags & DL_FLAG_RPM_ACTIVE)
821 refcount_inc(&link->rpm_active);
822
823 pm_runtime_new_link(consumer);
824 }
825
826 /* Determine the initial link state. */
827 if (flags & DL_FLAG_STATELESS)
828 link->status = DL_STATE_NONE;
829 else
830 device_link_init_status(link, consumer, supplier);
831
832 /*
833 * Some callers expect the link creation during consumer driver probe to
834 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
835 */
836 if (link->status == DL_STATE_CONSUMER_PROBE &&
837 flags & DL_FLAG_PM_RUNTIME)
838 pm_runtime_resume(supplier);
839
840 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
841 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
842
843 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
844 dev_dbg(consumer,
845 "Linked as a sync state only consumer to %s\n",
846 dev_name(supplier));
847 goto out;
848 }
849
850reorder:
851 /*
852 * Move the consumer and all of the devices depending on it to the end
853 * of dpm_list and the devices_kset list.
854 *
855 * It is necessary to hold dpm_list locked throughout all that or else
856 * we may end up suspending with a wrong ordering of it.
857 */
858 device_reorder_to_tail(consumer, NULL);
859
860 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
861
862out:
863 device_pm_unlock();
864 device_links_write_unlock();
865
866 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
867 pm_runtime_put(supplier);
868
869 return link;
870}
871EXPORT_SYMBOL_GPL(device_link_add);
872
873static void __device_link_del(struct kref *kref)
874{
875 struct device_link *link = container_of(kref, struct device_link, kref);
876
877 dev_dbg(link->consumer, "Dropping the link to %s\n",
878 dev_name(link->supplier));
879
880 pm_runtime_drop_link(link);
881
882 device_link_remove_from_lists(link);
883 device_unregister(&link->link_dev);
884}
885
886static void device_link_put_kref(struct device_link *link)
887{
888 if (link->flags & DL_FLAG_STATELESS)
889 kref_put(&link->kref, __device_link_del);
890 else if (!device_is_registered(link->consumer))
891 __device_link_del(&link->kref);
892 else
893 WARN(1, "Unable to drop a managed device link reference\n");
894}
895
896/**
897 * device_link_del - Delete a stateless link between two devices.
898 * @link: Device link to delete.
899 *
900 * The caller must ensure proper synchronization of this function with runtime
901 * PM. If the link was added multiple times, it needs to be deleted as often.
902 * Care is required for hotplugged devices: Their links are purged on removal
903 * and calling device_link_del() is then no longer allowed.
904 */
905void device_link_del(struct device_link *link)
906{
907 device_links_write_lock();
908 device_link_put_kref(link);
909 device_links_write_unlock();
910}
911EXPORT_SYMBOL_GPL(device_link_del);
912
913/**
914 * device_link_remove - Delete a stateless link between two devices.
915 * @consumer: Consumer end of the link.
916 * @supplier: Supplier end of the link.
917 *
918 * The caller must ensure proper synchronization of this function with runtime
919 * PM.
920 */
921void device_link_remove(void *consumer, struct device *supplier)
922{
923 struct device_link *link;
924
925 if (WARN_ON(consumer == supplier))
926 return;
927
928 device_links_write_lock();
929
930 list_for_each_entry(link, &supplier->links.consumers, s_node) {
931 if (link->consumer == consumer) {
932 device_link_put_kref(link);
933 break;
934 }
935 }
936
937 device_links_write_unlock();
938}
939EXPORT_SYMBOL_GPL(device_link_remove);
940
941static void device_links_missing_supplier(struct device *dev)
942{
943 struct device_link *link;
944
945 list_for_each_entry(link, &dev->links.suppliers, c_node) {
946 if (link->status != DL_STATE_CONSUMER_PROBE)
947 continue;
948
949 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
950 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
951 } else {
952 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
953 WRITE_ONCE(link->status, DL_STATE_DORMANT);
954 }
955 }
956}
957
958/**
959 * device_links_check_suppliers - Check presence of supplier drivers.
960 * @dev: Consumer device.
961 *
962 * Check links from this device to any suppliers. Walk the list of the device's
963 * links to suppliers and see if all of them are available. If not, simply
964 * return -EPROBE_DEFER.
965 *
966 * We need to guarantee that the supplier will not go away after the check has
967 * been positive here. It only can go away in __device_release_driver() and
968 * that function checks the device's links to consumers. This means we need to
969 * mark the link as "consumer probe in progress" to make the supplier removal
970 * wait for us to complete (or bad things may happen).
971 *
972 * Links without the DL_FLAG_MANAGED flag set are ignored.
973 */
974int device_links_check_suppliers(struct device *dev)
975{
976 struct device_link *link;
977 int ret = 0;
978
979 /*
980 * Device waiting for supplier to become available is not allowed to
981 * probe.
982 */
983 mutex_lock(&fwnode_link_lock);
984 if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) &&
985 !fw_devlink_is_permissive()) {
986 dev_dbg(dev, "probe deferral - wait for supplier %pfwP\n",
987 list_first_entry(&dev->fwnode->suppliers,
988 struct fwnode_link,
989 c_hook)->supplier);
990 mutex_unlock(&fwnode_link_lock);
991 return -EPROBE_DEFER;
992 }
993 mutex_unlock(&fwnode_link_lock);
994
995 device_links_write_lock();
996
997 list_for_each_entry(link, &dev->links.suppliers, c_node) {
998 if (!(link->flags & DL_FLAG_MANAGED))
999 continue;
1000
1001 if (link->status != DL_STATE_AVAILABLE &&
1002 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
1003 device_links_missing_supplier(dev);
1004 dev_dbg(dev, "probe deferral - supplier %s not ready\n",
1005 dev_name(link->supplier));
1006 ret = -EPROBE_DEFER;
1007 break;
1008 }
1009 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1010 }
1011 dev->links.status = DL_DEV_PROBING;
1012
1013 device_links_write_unlock();
1014 return ret;
1015}
1016
1017/**
1018 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1019 * @dev: Device to call sync_state() on
1020 * @list: List head to queue the @dev on
1021 *
1022 * Queues a device for a sync_state() callback when the device links write lock
1023 * isn't held. This allows the sync_state() execution flow to use device links
1024 * APIs. The caller must ensure this function is called with
1025 * device_links_write_lock() held.
1026 *
1027 * This function does a get_device() to make sure the device is not freed while
1028 * on this list.
1029 *
1030 * So the caller must also ensure that device_links_flush_sync_list() is called
1031 * as soon as the caller releases device_links_write_lock(). This is necessary
1032 * to make sure the sync_state() is called in a timely fashion and the
1033 * put_device() is called on this device.
1034 */
1035static void __device_links_queue_sync_state(struct device *dev,
1036 struct list_head *list)
1037{
1038 struct device_link *link;
1039
1040 if (!dev_has_sync_state(dev))
1041 return;
1042 if (dev->state_synced)
1043 return;
1044
1045 list_for_each_entry(link, &dev->links.consumers, s_node) {
1046 if (!(link->flags & DL_FLAG_MANAGED))
1047 continue;
1048 if (link->status != DL_STATE_ACTIVE)
1049 return;
1050 }
1051
1052 /*
1053 * Set the flag here to avoid adding the same device to a list more
1054 * than once. This can happen if new consumers get added to the device
1055 * and probed before the list is flushed.
1056 */
1057 dev->state_synced = true;
1058
1059 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1060 return;
1061
1062 get_device(dev);
1063 list_add_tail(&dev->links.defer_sync, list);
1064}
1065
1066/**
1067 * device_links_flush_sync_list - Call sync_state() on a list of devices
1068 * @list: List of devices to call sync_state() on
1069 * @dont_lock_dev: Device for which lock is already held by the caller
1070 *
1071 * Calls sync_state() on all the devices that have been queued for it. This
1072 * function is used in conjunction with __device_links_queue_sync_state(). The
1073 * @dont_lock_dev parameter is useful when this function is called from a
1074 * context where a device lock is already held.
1075 */
1076static void device_links_flush_sync_list(struct list_head *list,
1077 struct device *dont_lock_dev)
1078{
1079 struct device *dev, *tmp;
1080
1081 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1082 list_del_init(&dev->links.defer_sync);
1083
1084 if (dev != dont_lock_dev)
1085 device_lock(dev);
1086
1087 if (dev->bus->sync_state)
1088 dev->bus->sync_state(dev);
1089 else if (dev->driver && dev->driver->sync_state)
1090 dev->driver->sync_state(dev);
1091
1092 if (dev != dont_lock_dev)
1093 device_unlock(dev);
1094
1095 put_device(dev);
1096 }
1097}
1098
1099void device_links_supplier_sync_state_pause(void)
1100{
1101 device_links_write_lock();
1102 defer_sync_state_count++;
1103 device_links_write_unlock();
1104}
1105
1106void device_links_supplier_sync_state_resume(void)
1107{
1108 struct device *dev, *tmp;
1109 LIST_HEAD(sync_list);
1110
1111 device_links_write_lock();
1112 if (!defer_sync_state_count) {
1113 WARN(true, "Unmatched sync_state pause/resume!");
1114 goto out;
1115 }
1116 defer_sync_state_count--;
1117 if (defer_sync_state_count)
1118 goto out;
1119
1120 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1121 /*
1122 * Delete from deferred_sync list before queuing it to
1123 * sync_list because defer_sync is used for both lists.
1124 */
1125 list_del_init(&dev->links.defer_sync);
1126 __device_links_queue_sync_state(dev, &sync_list);
1127 }
1128out:
1129 device_links_write_unlock();
1130
1131 device_links_flush_sync_list(&sync_list, NULL);
1132}
1133
1134static int sync_state_resume_initcall(void)
1135{
1136 device_links_supplier_sync_state_resume();
1137 return 0;
1138}
1139late_initcall(sync_state_resume_initcall);
1140
1141static void __device_links_supplier_defer_sync(struct device *sup)
1142{
1143 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1144 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1145}
1146
1147static void device_link_drop_managed(struct device_link *link)
1148{
1149 link->flags &= ~DL_FLAG_MANAGED;
1150 WRITE_ONCE(link->status, DL_STATE_NONE);
1151 kref_put(&link->kref, __device_link_del);
1152}
1153
1154static ssize_t waiting_for_supplier_show(struct device *dev,
1155 struct device_attribute *attr,
1156 char *buf)
1157{
1158 bool val;
1159
1160 device_lock(dev);
1161 val = !list_empty(&dev->fwnode->suppliers);
1162 device_unlock(dev);
1163 return sysfs_emit(buf, "%u\n", val);
1164}
1165static DEVICE_ATTR_RO(waiting_for_supplier);
1166
1167/**
1168 * device_links_force_bind - Prepares device to be force bound
1169 * @dev: Consumer device.
1170 *
1171 * device_bind_driver() force binds a device to a driver without calling any
1172 * driver probe functions. So the consumer really isn't going to wait for any
1173 * supplier before it's bound to the driver. We still want the device link
1174 * states to be sensible when this happens.
1175 *
1176 * In preparation for device_bind_driver(), this function goes through each
1177 * supplier device links and checks if the supplier is bound. If it is, then
1178 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1179 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1180 */
1181void device_links_force_bind(struct device *dev)
1182{
1183 struct device_link *link, *ln;
1184
1185 device_links_write_lock();
1186
1187 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1188 if (!(link->flags & DL_FLAG_MANAGED))
1189 continue;
1190
1191 if (link->status != DL_STATE_AVAILABLE) {
1192 device_link_drop_managed(link);
1193 continue;
1194 }
1195 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1196 }
1197 dev->links.status = DL_DEV_PROBING;
1198
1199 device_links_write_unlock();
1200}
1201
1202/**
1203 * device_links_driver_bound - Update device links after probing its driver.
1204 * @dev: Device to update the links for.
1205 *
1206 * The probe has been successful, so update links from this device to any
1207 * consumers by changing their status to "available".
1208 *
1209 * Also change the status of @dev's links to suppliers to "active".
1210 *
1211 * Links without the DL_FLAG_MANAGED flag set are ignored.
1212 */
1213void device_links_driver_bound(struct device *dev)
1214{
1215 struct device_link *link, *ln;
1216 LIST_HEAD(sync_list);
1217
1218 /*
1219 * If a device binds successfully, it's expected to have created all
1220 * the device links it needs to or make new device links as it needs
1221 * them. So, fw_devlink no longer needs to create device links to any
1222 * of the device's suppliers.
1223 *
1224 * Also, if a child firmware node of this bound device is not added as
1225 * a device by now, assume it is never going to be added and make sure
1226 * other devices don't defer probe indefinitely by waiting for such a
1227 * child device.
1228 */
1229 if (dev->fwnode && dev->fwnode->dev == dev) {
1230 struct fwnode_handle *child;
1231 fwnode_links_purge_suppliers(dev->fwnode);
1232 fwnode_for_each_available_child_node(dev->fwnode, child)
1233 fw_devlink_purge_absent_suppliers(child);
1234 }
1235 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1236
1237 device_links_write_lock();
1238
1239 list_for_each_entry(link, &dev->links.consumers, s_node) {
1240 if (!(link->flags & DL_FLAG_MANAGED))
1241 continue;
1242
1243 /*
1244 * Links created during consumer probe may be in the "consumer
1245 * probe" state to start with if the supplier is still probing
1246 * when they are created and they may become "active" if the
1247 * consumer probe returns first. Skip them here.
1248 */
1249 if (link->status == DL_STATE_CONSUMER_PROBE ||
1250 link->status == DL_STATE_ACTIVE)
1251 continue;
1252
1253 WARN_ON(link->status != DL_STATE_DORMANT);
1254 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1255
1256 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1257 driver_deferred_probe_add(link->consumer);
1258 }
1259
1260 if (defer_sync_state_count)
1261 __device_links_supplier_defer_sync(dev);
1262 else
1263 __device_links_queue_sync_state(dev, &sync_list);
1264
1265 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1266 struct device *supplier;
1267
1268 if (!(link->flags & DL_FLAG_MANAGED))
1269 continue;
1270
1271 supplier = link->supplier;
1272 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1273 /*
1274 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1275 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1276 * save to drop the managed link completely.
1277 */
1278 device_link_drop_managed(link);
1279 } else {
1280 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1281 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1282 }
1283
1284 /*
1285 * This needs to be done even for the deleted
1286 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1287 * device link that was preventing the supplier from getting a
1288 * sync_state() call.
1289 */
1290 if (defer_sync_state_count)
1291 __device_links_supplier_defer_sync(supplier);
1292 else
1293 __device_links_queue_sync_state(supplier, &sync_list);
1294 }
1295
1296 dev->links.status = DL_DEV_DRIVER_BOUND;
1297
1298 device_links_write_unlock();
1299
1300 device_links_flush_sync_list(&sync_list, dev);
1301}
1302
1303/**
1304 * __device_links_no_driver - Update links of a device without a driver.
1305 * @dev: Device without a drvier.
1306 *
1307 * Delete all non-persistent links from this device to any suppliers.
1308 *
1309 * Persistent links stay around, but their status is changed to "available",
1310 * unless they already are in the "supplier unbind in progress" state in which
1311 * case they need not be updated.
1312 *
1313 * Links without the DL_FLAG_MANAGED flag set are ignored.
1314 */
1315static void __device_links_no_driver(struct device *dev)
1316{
1317 struct device_link *link, *ln;
1318
1319 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1320 if (!(link->flags & DL_FLAG_MANAGED))
1321 continue;
1322
1323 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1324 device_link_drop_managed(link);
1325 continue;
1326 }
1327
1328 if (link->status != DL_STATE_CONSUMER_PROBE &&
1329 link->status != DL_STATE_ACTIVE)
1330 continue;
1331
1332 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1333 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1334 } else {
1335 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1336 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1337 }
1338 }
1339
1340 dev->links.status = DL_DEV_NO_DRIVER;
1341}
1342
1343/**
1344 * device_links_no_driver - Update links after failing driver probe.
1345 * @dev: Device whose driver has just failed to probe.
1346 *
1347 * Clean up leftover links to consumers for @dev and invoke
1348 * %__device_links_no_driver() to update links to suppliers for it as
1349 * appropriate.
1350 *
1351 * Links without the DL_FLAG_MANAGED flag set are ignored.
1352 */
1353void device_links_no_driver(struct device *dev)
1354{
1355 struct device_link *link;
1356
1357 device_links_write_lock();
1358
1359 list_for_each_entry(link, &dev->links.consumers, s_node) {
1360 if (!(link->flags & DL_FLAG_MANAGED))
1361 continue;
1362
1363 /*
1364 * The probe has failed, so if the status of the link is
1365 * "consumer probe" or "active", it must have been added by
1366 * a probing consumer while this device was still probing.
1367 * Change its state to "dormant", as it represents a valid
1368 * relationship, but it is not functionally meaningful.
1369 */
1370 if (link->status == DL_STATE_CONSUMER_PROBE ||
1371 link->status == DL_STATE_ACTIVE)
1372 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1373 }
1374
1375 __device_links_no_driver(dev);
1376
1377 device_links_write_unlock();
1378}
1379
1380/**
1381 * device_links_driver_cleanup - Update links after driver removal.
1382 * @dev: Device whose driver has just gone away.
1383 *
1384 * Update links to consumers for @dev by changing their status to "dormant" and
1385 * invoke %__device_links_no_driver() to update links to suppliers for it as
1386 * appropriate.
1387 *
1388 * Links without the DL_FLAG_MANAGED flag set are ignored.
1389 */
1390void device_links_driver_cleanup(struct device *dev)
1391{
1392 struct device_link *link, *ln;
1393
1394 device_links_write_lock();
1395
1396 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1397 if (!(link->flags & DL_FLAG_MANAGED))
1398 continue;
1399
1400 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1401 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1402
1403 /*
1404 * autoremove the links between this @dev and its consumer
1405 * devices that are not active, i.e. where the link state
1406 * has moved to DL_STATE_SUPPLIER_UNBIND.
1407 */
1408 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1409 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1410 device_link_drop_managed(link);
1411
1412 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1413 }
1414
1415 list_del_init(&dev->links.defer_sync);
1416 __device_links_no_driver(dev);
1417
1418 device_links_write_unlock();
1419}
1420
1421/**
1422 * device_links_busy - Check if there are any busy links to consumers.
1423 * @dev: Device to check.
1424 *
1425 * Check each consumer of the device and return 'true' if its link's status
1426 * is one of "consumer probe" or "active" (meaning that the given consumer is
1427 * probing right now or its driver is present). Otherwise, change the link
1428 * state to "supplier unbind" to prevent the consumer from being probed
1429 * successfully going forward.
1430 *
1431 * Return 'false' if there are no probing or active consumers.
1432 *
1433 * Links without the DL_FLAG_MANAGED flag set are ignored.
1434 */
1435bool device_links_busy(struct device *dev)
1436{
1437 struct device_link *link;
1438 bool ret = false;
1439
1440 device_links_write_lock();
1441
1442 list_for_each_entry(link, &dev->links.consumers, s_node) {
1443 if (!(link->flags & DL_FLAG_MANAGED))
1444 continue;
1445
1446 if (link->status == DL_STATE_CONSUMER_PROBE
1447 || link->status == DL_STATE_ACTIVE) {
1448 ret = true;
1449 break;
1450 }
1451 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1452 }
1453
1454 dev->links.status = DL_DEV_UNBINDING;
1455
1456 device_links_write_unlock();
1457 return ret;
1458}
1459
1460/**
1461 * device_links_unbind_consumers - Force unbind consumers of the given device.
1462 * @dev: Device to unbind the consumers of.
1463 *
1464 * Walk the list of links to consumers for @dev and if any of them is in the
1465 * "consumer probe" state, wait for all device probes in progress to complete
1466 * and start over.
1467 *
1468 * If that's not the case, change the status of the link to "supplier unbind"
1469 * and check if the link was in the "active" state. If so, force the consumer
1470 * driver to unbind and start over (the consumer will not re-probe as we have
1471 * changed the state of the link already).
1472 *
1473 * Links without the DL_FLAG_MANAGED flag set are ignored.
1474 */
1475void device_links_unbind_consumers(struct device *dev)
1476{
1477 struct device_link *link;
1478
1479 start:
1480 device_links_write_lock();
1481
1482 list_for_each_entry(link, &dev->links.consumers, s_node) {
1483 enum device_link_state status;
1484
1485 if (!(link->flags & DL_FLAG_MANAGED) ||
1486 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1487 continue;
1488
1489 status = link->status;
1490 if (status == DL_STATE_CONSUMER_PROBE) {
1491 device_links_write_unlock();
1492
1493 wait_for_device_probe();
1494 goto start;
1495 }
1496 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1497 if (status == DL_STATE_ACTIVE) {
1498 struct device *consumer = link->consumer;
1499
1500 get_device(consumer);
1501
1502 device_links_write_unlock();
1503
1504 device_release_driver_internal(consumer, NULL,
1505 consumer->parent);
1506 put_device(consumer);
1507 goto start;
1508 }
1509 }
1510
1511 device_links_write_unlock();
1512}
1513
1514/**
1515 * device_links_purge - Delete existing links to other devices.
1516 * @dev: Target device.
1517 */
1518static void device_links_purge(struct device *dev)
1519{
1520 struct device_link *link, *ln;
1521
1522 if (dev->class == &devlink_class)
1523 return;
1524
1525 /*
1526 * Delete all of the remaining links from this device to any other
1527 * devices (either consumers or suppliers).
1528 */
1529 device_links_write_lock();
1530
1531 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1532 WARN_ON(link->status == DL_STATE_ACTIVE);
1533 __device_link_del(&link->kref);
1534 }
1535
1536 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1537 WARN_ON(link->status != DL_STATE_DORMANT &&
1538 link->status != DL_STATE_NONE);
1539 __device_link_del(&link->kref);
1540 }
1541
1542 device_links_write_unlock();
1543}
1544
1545#define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1546 DL_FLAG_SYNC_STATE_ONLY)
1547#define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1548 DL_FLAG_AUTOPROBE_CONSUMER)
1549#define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1550 DL_FLAG_PM_RUNTIME)
1551
1552static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1553static int __init fw_devlink_setup(char *arg)
1554{
1555 if (!arg)
1556 return -EINVAL;
1557
1558 if (strcmp(arg, "off") == 0) {
1559 fw_devlink_flags = 0;
1560 } else if (strcmp(arg, "permissive") == 0) {
1561 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1562 } else if (strcmp(arg, "on") == 0) {
1563 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1564 } else if (strcmp(arg, "rpm") == 0) {
1565 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1566 }
1567 return 0;
1568}
1569early_param("fw_devlink", fw_devlink_setup);
1570
1571static bool fw_devlink_strict;
1572static int __init fw_devlink_strict_setup(char *arg)
1573{
1574 return strtobool(arg, &fw_devlink_strict);
1575}
1576early_param("fw_devlink.strict", fw_devlink_strict_setup);
1577
1578u32 fw_devlink_get_flags(void)
1579{
1580 return fw_devlink_flags;
1581}
1582
1583static bool fw_devlink_is_permissive(void)
1584{
1585 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1586}
1587
1588bool fw_devlink_is_strict(void)
1589{
1590 return fw_devlink_strict && !fw_devlink_is_permissive();
1591}
1592
1593static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1594{
1595 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1596 return;
1597
1598 fwnode_call_int_op(fwnode, add_links);
1599 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1600}
1601
1602static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1603{
1604 struct fwnode_handle *child = NULL;
1605
1606 fw_devlink_parse_fwnode(fwnode);
1607
1608 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1609 fw_devlink_parse_fwtree(child);
1610}
1611
1612static void fw_devlink_relax_link(struct device_link *link)
1613{
1614 if (!(link->flags & DL_FLAG_INFERRED))
1615 return;
1616
1617 if (link->flags == (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE))
1618 return;
1619
1620 pm_runtime_drop_link(link);
1621 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1622 dev_dbg(link->consumer, "Relaxing link with %s\n",
1623 dev_name(link->supplier));
1624}
1625
1626static int fw_devlink_no_driver(struct device *dev, void *data)
1627{
1628 struct device_link *link = to_devlink(dev);
1629
1630 if (!link->supplier->can_match)
1631 fw_devlink_relax_link(link);
1632
1633 return 0;
1634}
1635
1636void fw_devlink_drivers_done(void)
1637{
1638 fw_devlink_drv_reg_done = true;
1639 device_links_write_lock();
1640 class_for_each_device(&devlink_class, NULL, NULL,
1641 fw_devlink_no_driver);
1642 device_links_write_unlock();
1643}
1644
1645static void fw_devlink_unblock_consumers(struct device *dev)
1646{
1647 struct device_link *link;
1648
1649 if (!fw_devlink_flags || fw_devlink_is_permissive())
1650 return;
1651
1652 device_links_write_lock();
1653 list_for_each_entry(link, &dev->links.consumers, s_node)
1654 fw_devlink_relax_link(link);
1655 device_links_write_unlock();
1656}
1657
1658/**
1659 * fw_devlink_relax_cycle - Convert cyclic links to SYNC_STATE_ONLY links
1660 * @con: Device to check dependencies for.
1661 * @sup: Device to check against.
1662 *
1663 * Check if @sup depends on @con or any device dependent on it (its child or
1664 * its consumer etc). When such a cyclic dependency is found, convert all
1665 * device links created solely by fw_devlink into SYNC_STATE_ONLY device links.
1666 * This is the equivalent of doing fw_devlink=permissive just between the
1667 * devices in the cycle. We need to do this because, at this point, fw_devlink
1668 * can't tell which of these dependencies is not a real dependency.
1669 *
1670 * Return 1 if a cycle is found. Otherwise, return 0.
1671 */
1672static int fw_devlink_relax_cycle(struct device *con, void *sup)
1673{
1674 struct device_link *link;
1675 int ret;
1676
1677 if (con == sup)
1678 return 1;
1679
1680 ret = device_for_each_child(con, sup, fw_devlink_relax_cycle);
1681 if (ret)
1682 return ret;
1683
1684 list_for_each_entry(link, &con->links.consumers, s_node) {
1685 if ((link->flags & ~DL_FLAG_INFERRED) ==
1686 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
1687 continue;
1688
1689 if (!fw_devlink_relax_cycle(link->consumer, sup))
1690 continue;
1691
1692 ret = 1;
1693
1694 fw_devlink_relax_link(link);
1695 }
1696 return ret;
1697}
1698
1699/**
1700 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
1701 * @con: consumer device for the device link
1702 * @sup_handle: fwnode handle of supplier
1703 * @flags: devlink flags
1704 *
1705 * This function will try to create a device link between the consumer device
1706 * @con and the supplier device represented by @sup_handle.
1707 *
1708 * The supplier has to be provided as a fwnode because incorrect cycles in
1709 * fwnode links can sometimes cause the supplier device to never be created.
1710 * This function detects such cases and returns an error if it cannot create a
1711 * device link from the consumer to a missing supplier.
1712 *
1713 * Returns,
1714 * 0 on successfully creating a device link
1715 * -EINVAL if the device link cannot be created as expected
1716 * -EAGAIN if the device link cannot be created right now, but it may be
1717 * possible to do that in the future
1718 */
1719static int fw_devlink_create_devlink(struct device *con,
1720 struct fwnode_handle *sup_handle, u32 flags)
1721{
1722 struct device *sup_dev;
1723 int ret = 0;
1724
1725 /*
1726 * In some cases, a device P might also be a supplier to its child node
1727 * C. However, this would defer the probe of C until the probe of P
1728 * completes successfully. This is perfectly fine in the device driver
1729 * model. device_add() doesn't guarantee probe completion of the device
1730 * by the time it returns.
1731 *
1732 * However, there are a few drivers that assume C will finish probing
1733 * as soon as it's added and before P finishes probing. So, we provide
1734 * a flag to let fw_devlink know not to delay the probe of C until the
1735 * probe of P completes successfully.
1736 *
1737 * When such a flag is set, we can't create device links where P is the
1738 * supplier of C as that would delay the probe of C.
1739 */
1740 if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD &&
1741 fwnode_is_ancestor_of(sup_handle, con->fwnode))
1742 return -EINVAL;
1743
1744 sup_dev = get_dev_from_fwnode(sup_handle);
1745 if (sup_dev) {
1746 /*
1747 * If it's one of those drivers that don't actually bind to
1748 * their device using driver core, then don't wait on this
1749 * supplier device indefinitely.
1750 */
1751 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
1752 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
1753 ret = -EINVAL;
1754 goto out;
1755 }
1756
1757 /*
1758 * If this fails, it is due to cycles in device links. Just
1759 * give up on this link and treat it as invalid.
1760 */
1761 if (!device_link_add(con, sup_dev, flags) &&
1762 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
1763 dev_info(con, "Fixing up cyclic dependency with %s\n",
1764 dev_name(sup_dev));
1765 device_links_write_lock();
1766 fw_devlink_relax_cycle(con, sup_dev);
1767 device_links_write_unlock();
1768 device_link_add(con, sup_dev,
1769 FW_DEVLINK_FLAGS_PERMISSIVE);
1770 ret = -EINVAL;
1771 }
1772
1773 goto out;
1774 }
1775
1776 /* Supplier that's already initialized without a struct device. */
1777 if (sup_handle->flags & FWNODE_FLAG_INITIALIZED)
1778 return -EINVAL;
1779
1780 /*
1781 * DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports
1782 * cycles. So cycle detection isn't necessary and shouldn't be
1783 * done.
1784 */
1785 if (flags & DL_FLAG_SYNC_STATE_ONLY)
1786 return -EAGAIN;
1787
1788 /*
1789 * If we can't find the supplier device from its fwnode, it might be
1790 * due to a cyclic dependency between fwnodes. Some of these cycles can
1791 * be broken by applying logic. Check for these types of cycles and
1792 * break them so that devices in the cycle probe properly.
1793 *
1794 * If the supplier's parent is dependent on the consumer, then the
1795 * consumer and supplier have a cyclic dependency. Since fw_devlink
1796 * can't tell which of the inferred dependencies are incorrect, don't
1797 * enforce probe ordering between any of the devices in this cyclic
1798 * dependency. Do this by relaxing all the fw_devlink device links in
1799 * this cycle and by treating the fwnode link between the consumer and
1800 * the supplier as an invalid dependency.
1801 */
1802 sup_dev = fwnode_get_next_parent_dev(sup_handle);
1803 if (sup_dev && device_is_dependent(con, sup_dev)) {
1804 dev_info(con, "Fixing up cyclic dependency with %pfwP (%s)\n",
1805 sup_handle, dev_name(sup_dev));
1806 device_links_write_lock();
1807 fw_devlink_relax_cycle(con, sup_dev);
1808 device_links_write_unlock();
1809 ret = -EINVAL;
1810 } else {
1811 /*
1812 * Can't check for cycles or no cycles. So let's try
1813 * again later.
1814 */
1815 ret = -EAGAIN;
1816 }
1817
1818out:
1819 put_device(sup_dev);
1820 return ret;
1821}
1822
1823/**
1824 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
1825 * @dev: Device that needs to be linked to its consumers
1826 *
1827 * This function looks at all the consumer fwnodes of @dev and creates device
1828 * links between the consumer device and @dev (supplier).
1829 *
1830 * If the consumer device has not been added yet, then this function creates a
1831 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
1832 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
1833 * sync_state() callback before the real consumer device gets to be added and
1834 * then probed.
1835 *
1836 * Once device links are created from the real consumer to @dev (supplier), the
1837 * fwnode links are deleted.
1838 */
1839static void __fw_devlink_link_to_consumers(struct device *dev)
1840{
1841 struct fwnode_handle *fwnode = dev->fwnode;
1842 struct fwnode_link *link, *tmp;
1843
1844 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
1845 u32 dl_flags = fw_devlink_get_flags();
1846 struct device *con_dev;
1847 bool own_link = true;
1848 int ret;
1849
1850 con_dev = get_dev_from_fwnode(link->consumer);
1851 /*
1852 * If consumer device is not available yet, make a "proxy"
1853 * SYNC_STATE_ONLY link from the consumer's parent device to
1854 * the supplier device. This is necessary to make sure the
1855 * supplier doesn't get a sync_state() callback before the real
1856 * consumer can create a device link to the supplier.
1857 *
1858 * This proxy link step is needed to handle the case where the
1859 * consumer's parent device is added before the supplier.
1860 */
1861 if (!con_dev) {
1862 con_dev = fwnode_get_next_parent_dev(link->consumer);
1863 /*
1864 * However, if the consumer's parent device is also the
1865 * parent of the supplier, don't create a
1866 * consumer-supplier link from the parent to its child
1867 * device. Such a dependency is impossible.
1868 */
1869 if (con_dev &&
1870 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
1871 put_device(con_dev);
1872 con_dev = NULL;
1873 } else {
1874 own_link = false;
1875 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1876 }
1877 }
1878
1879 if (!con_dev)
1880 continue;
1881
1882 ret = fw_devlink_create_devlink(con_dev, fwnode, dl_flags);
1883 put_device(con_dev);
1884 if (!own_link || ret == -EAGAIN)
1885 continue;
1886
1887 list_del(&link->s_hook);
1888 list_del(&link->c_hook);
1889 kfree(link);
1890 }
1891}
1892
1893/**
1894 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
1895 * @dev: The consumer device that needs to be linked to its suppliers
1896 * @fwnode: Root of the fwnode tree that is used to create device links
1897 *
1898 * This function looks at all the supplier fwnodes of fwnode tree rooted at
1899 * @fwnode and creates device links between @dev (consumer) and all the
1900 * supplier devices of the entire fwnode tree at @fwnode.
1901 *
1902 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
1903 * and the real suppliers of @dev. Once these device links are created, the
1904 * fwnode links are deleted. When such device links are successfully created,
1905 * this function is called recursively on those supplier devices. This is
1906 * needed to detect and break some invalid cycles in fwnode links. See
1907 * fw_devlink_create_devlink() for more details.
1908 *
1909 * In addition, it also looks at all the suppliers of the entire fwnode tree
1910 * because some of the child devices of @dev that have not been added yet
1911 * (because @dev hasn't probed) might already have their suppliers added to
1912 * driver core. So, this function creates SYNC_STATE_ONLY device links between
1913 * @dev (consumer) and these suppliers to make sure they don't execute their
1914 * sync_state() callbacks before these child devices have a chance to create
1915 * their device links. The fwnode links that correspond to the child devices
1916 * aren't delete because they are needed later to create the device links
1917 * between the real consumer and supplier devices.
1918 */
1919static void __fw_devlink_link_to_suppliers(struct device *dev,
1920 struct fwnode_handle *fwnode)
1921{
1922 bool own_link = (dev->fwnode == fwnode);
1923 struct fwnode_link *link, *tmp;
1924 struct fwnode_handle *child = NULL;
1925 u32 dl_flags;
1926
1927 if (own_link)
1928 dl_flags = fw_devlink_get_flags();
1929 else
1930 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1931
1932 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
1933 int ret;
1934 struct device *sup_dev;
1935 struct fwnode_handle *sup = link->supplier;
1936
1937 ret = fw_devlink_create_devlink(dev, sup, dl_flags);
1938 if (!own_link || ret == -EAGAIN)
1939 continue;
1940
1941 list_del(&link->s_hook);
1942 list_del(&link->c_hook);
1943 kfree(link);
1944
1945 /* If no device link was created, nothing more to do. */
1946 if (ret)
1947 continue;
1948
1949 /*
1950 * If a device link was successfully created to a supplier, we
1951 * now need to try and link the supplier to all its suppliers.
1952 *
1953 * This is needed to detect and delete false dependencies in
1954 * fwnode links that haven't been converted to a device link
1955 * yet. See comments in fw_devlink_create_devlink() for more
1956 * details on the false dependency.
1957 *
1958 * Without deleting these false dependencies, some devices will
1959 * never probe because they'll keep waiting for their false
1960 * dependency fwnode links to be converted to device links.
1961 */
1962 sup_dev = get_dev_from_fwnode(sup);
1963 __fw_devlink_link_to_suppliers(sup_dev, sup_dev->fwnode);
1964 put_device(sup_dev);
1965 }
1966
1967 /*
1968 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
1969 * all the descendants. This proxy link step is needed to handle the
1970 * case where the supplier is added before the consumer's parent device
1971 * (@dev).
1972 */
1973 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1974 __fw_devlink_link_to_suppliers(dev, child);
1975}
1976
1977static void fw_devlink_link_device(struct device *dev)
1978{
1979 struct fwnode_handle *fwnode = dev->fwnode;
1980
1981 if (!fw_devlink_flags)
1982 return;
1983
1984 fw_devlink_parse_fwtree(fwnode);
1985
1986 mutex_lock(&fwnode_link_lock);
1987 __fw_devlink_link_to_consumers(dev);
1988 __fw_devlink_link_to_suppliers(dev, fwnode);
1989 mutex_unlock(&fwnode_link_lock);
1990}
1991
1992/* Device links support end. */
1993
1994int (*platform_notify)(struct device *dev) = NULL;
1995int (*platform_notify_remove)(struct device *dev) = NULL;
1996static struct kobject *dev_kobj;
1997struct kobject *sysfs_dev_char_kobj;
1998struct kobject *sysfs_dev_block_kobj;
1999
2000static DEFINE_MUTEX(device_hotplug_lock);
2001
2002void lock_device_hotplug(void)
2003{
2004 mutex_lock(&device_hotplug_lock);
2005}
2006
2007void unlock_device_hotplug(void)
2008{
2009 mutex_unlock(&device_hotplug_lock);
2010}
2011
2012int lock_device_hotplug_sysfs(void)
2013{
2014 if (mutex_trylock(&device_hotplug_lock))
2015 return 0;
2016
2017 /* Avoid busy looping (5 ms of sleep should do). */
2018 msleep(5);
2019 return restart_syscall();
2020}
2021
2022#ifdef CONFIG_BLOCK
2023static inline int device_is_not_partition(struct device *dev)
2024{
2025 return !(dev->type == &part_type);
2026}
2027#else
2028static inline int device_is_not_partition(struct device *dev)
2029{
2030 return 1;
2031}
2032#endif
2033
2034static int
2035device_platform_notify(struct device *dev, enum kobject_action action)
2036{
2037 int ret;
2038
2039 ret = acpi_platform_notify(dev, action);
2040 if (ret)
2041 return ret;
2042
2043 ret = software_node_notify(dev, action);
2044 if (ret)
2045 return ret;
2046
2047 if (platform_notify && action == KOBJ_ADD)
2048 platform_notify(dev);
2049 else if (platform_notify_remove && action == KOBJ_REMOVE)
2050 platform_notify_remove(dev);
2051 return 0;
2052}
2053
2054/**
2055 * dev_driver_string - Return a device's driver name, if at all possible
2056 * @dev: struct device to get the name of
2057 *
2058 * Will return the device's driver's name if it is bound to a device. If
2059 * the device is not bound to a driver, it will return the name of the bus
2060 * it is attached to. If it is not attached to a bus either, an empty
2061 * string will be returned.
2062 */
2063const char *dev_driver_string(const struct device *dev)
2064{
2065 struct device_driver *drv;
2066
2067 /* dev->driver can change to NULL underneath us because of unbinding,
2068 * so be careful about accessing it. dev->bus and dev->class should
2069 * never change once they are set, so they don't need special care.
2070 */
2071 drv = READ_ONCE(dev->driver);
2072 return drv ? drv->name : dev_bus_name(dev);
2073}
2074EXPORT_SYMBOL(dev_driver_string);
2075
2076#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2077
2078static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2079 char *buf)
2080{
2081 struct device_attribute *dev_attr = to_dev_attr(attr);
2082 struct device *dev = kobj_to_dev(kobj);
2083 ssize_t ret = -EIO;
2084
2085 if (dev_attr->show)
2086 ret = dev_attr->show(dev, dev_attr, buf);
2087 if (ret >= (ssize_t)PAGE_SIZE) {
2088 printk("dev_attr_show: %pS returned bad count\n",
2089 dev_attr->show);
2090 }
2091 return ret;
2092}
2093
2094static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2095 const char *buf, size_t count)
2096{
2097 struct device_attribute *dev_attr = to_dev_attr(attr);
2098 struct device *dev = kobj_to_dev(kobj);
2099 ssize_t ret = -EIO;
2100
2101 if (dev_attr->store)
2102 ret = dev_attr->store(dev, dev_attr, buf, count);
2103 return ret;
2104}
2105
2106static const struct sysfs_ops dev_sysfs_ops = {
2107 .show = dev_attr_show,
2108 .store = dev_attr_store,
2109};
2110
2111#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2112
2113ssize_t device_store_ulong(struct device *dev,
2114 struct device_attribute *attr,
2115 const char *buf, size_t size)
2116{
2117 struct dev_ext_attribute *ea = to_ext_attr(attr);
2118 int ret;
2119 unsigned long new;
2120
2121 ret = kstrtoul(buf, 0, &new);
2122 if (ret)
2123 return ret;
2124 *(unsigned long *)(ea->var) = new;
2125 /* Always return full write size even if we didn't consume all */
2126 return size;
2127}
2128EXPORT_SYMBOL_GPL(device_store_ulong);
2129
2130ssize_t device_show_ulong(struct device *dev,
2131 struct device_attribute *attr,
2132 char *buf)
2133{
2134 struct dev_ext_attribute *ea = to_ext_attr(attr);
2135 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2136}
2137EXPORT_SYMBOL_GPL(device_show_ulong);
2138
2139ssize_t device_store_int(struct device *dev,
2140 struct device_attribute *attr,
2141 const char *buf, size_t size)
2142{
2143 struct dev_ext_attribute *ea = to_ext_attr(attr);
2144 int ret;
2145 long new;
2146
2147 ret = kstrtol(buf, 0, &new);
2148 if (ret)
2149 return ret;
2150
2151 if (new > INT_MAX || new < INT_MIN)
2152 return -EINVAL;
2153 *(int *)(ea->var) = new;
2154 /* Always return full write size even if we didn't consume all */
2155 return size;
2156}
2157EXPORT_SYMBOL_GPL(device_store_int);
2158
2159ssize_t device_show_int(struct device *dev,
2160 struct device_attribute *attr,
2161 char *buf)
2162{
2163 struct dev_ext_attribute *ea = to_ext_attr(attr);
2164
2165 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2166}
2167EXPORT_SYMBOL_GPL(device_show_int);
2168
2169ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2170 const char *buf, size_t size)
2171{
2172 struct dev_ext_attribute *ea = to_ext_attr(attr);
2173
2174 if (strtobool(buf, ea->var) < 0)
2175 return -EINVAL;
2176
2177 return size;
2178}
2179EXPORT_SYMBOL_GPL(device_store_bool);
2180
2181ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2182 char *buf)
2183{
2184 struct dev_ext_attribute *ea = to_ext_attr(attr);
2185
2186 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2187}
2188EXPORT_SYMBOL_GPL(device_show_bool);
2189
2190/**
2191 * device_release - free device structure.
2192 * @kobj: device's kobject.
2193 *
2194 * This is called once the reference count for the object
2195 * reaches 0. We forward the call to the device's release
2196 * method, which should handle actually freeing the structure.
2197 */
2198static void device_release(struct kobject *kobj)
2199{
2200 struct device *dev = kobj_to_dev(kobj);
2201 struct device_private *p = dev->p;
2202
2203 /*
2204 * Some platform devices are driven without driver attached
2205 * and managed resources may have been acquired. Make sure
2206 * all resources are released.
2207 *
2208 * Drivers still can add resources into device after device
2209 * is deleted but alive, so release devres here to avoid
2210 * possible memory leak.
2211 */
2212 devres_release_all(dev);
2213
2214 kfree(dev->dma_range_map);
2215
2216 if (dev->release)
2217 dev->release(dev);
2218 else if (dev->type && dev->type->release)
2219 dev->type->release(dev);
2220 else if (dev->class && dev->class->dev_release)
2221 dev->class->dev_release(dev);
2222 else
2223 WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
2224 dev_name(dev));
2225 kfree(p);
2226}
2227
2228static const void *device_namespace(struct kobject *kobj)
2229{
2230 struct device *dev = kobj_to_dev(kobj);
2231 const void *ns = NULL;
2232
2233 if (dev->class && dev->class->ns_type)
2234 ns = dev->class->namespace(dev);
2235
2236 return ns;
2237}
2238
2239static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2240{
2241 struct device *dev = kobj_to_dev(kobj);
2242
2243 if (dev->class && dev->class->get_ownership)
2244 dev->class->get_ownership(dev, uid, gid);
2245}
2246
2247static struct kobj_type device_ktype = {
2248 .release = device_release,
2249 .sysfs_ops = &dev_sysfs_ops,
2250 .namespace = device_namespace,
2251 .get_ownership = device_get_ownership,
2252};
2253
2254
2255static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
2256{
2257 struct kobj_type *ktype = get_ktype(kobj);
2258
2259 if (ktype == &device_ktype) {
2260 struct device *dev = kobj_to_dev(kobj);
2261 if (dev->bus)
2262 return 1;
2263 if (dev->class)
2264 return 1;
2265 }
2266 return 0;
2267}
2268
2269static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
2270{
2271 struct device *dev = kobj_to_dev(kobj);
2272
2273 if (dev->bus)
2274 return dev->bus->name;
2275 if (dev->class)
2276 return dev->class->name;
2277 return NULL;
2278}
2279
2280static int dev_uevent(struct kset *kset, struct kobject *kobj,
2281 struct kobj_uevent_env *env)
2282{
2283 struct device *dev = kobj_to_dev(kobj);
2284 int retval = 0;
2285
2286 /* add device node properties if present */
2287 if (MAJOR(dev->devt)) {
2288 const char *tmp;
2289 const char *name;
2290 umode_t mode = 0;
2291 kuid_t uid = GLOBAL_ROOT_UID;
2292 kgid_t gid = GLOBAL_ROOT_GID;
2293
2294 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2295 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2296 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2297 if (name) {
2298 add_uevent_var(env, "DEVNAME=%s", name);
2299 if (mode)
2300 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2301 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2302 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2303 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2304 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2305 kfree(tmp);
2306 }
2307 }
2308
2309 if (dev->type && dev->type->name)
2310 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2311
2312 if (dev->driver)
2313 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2314
2315 /* Add common DT information about the device */
2316 of_device_uevent(dev, env);
2317
2318 /* have the bus specific function add its stuff */
2319 if (dev->bus && dev->bus->uevent) {
2320 retval = dev->bus->uevent(dev, env);
2321 if (retval)
2322 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2323 dev_name(dev), __func__, retval);
2324 }
2325
2326 /* have the class specific function add its stuff */
2327 if (dev->class && dev->class->dev_uevent) {
2328 retval = dev->class->dev_uevent(dev, env);
2329 if (retval)
2330 pr_debug("device: '%s': %s: class uevent() "
2331 "returned %d\n", dev_name(dev),
2332 __func__, retval);
2333 }
2334
2335 /* have the device type specific function add its stuff */
2336 if (dev->type && dev->type->uevent) {
2337 retval = dev->type->uevent(dev, env);
2338 if (retval)
2339 pr_debug("device: '%s': %s: dev_type uevent() "
2340 "returned %d\n", dev_name(dev),
2341 __func__, retval);
2342 }
2343
2344 return retval;
2345}
2346
2347static const struct kset_uevent_ops device_uevent_ops = {
2348 .filter = dev_uevent_filter,
2349 .name = dev_uevent_name,
2350 .uevent = dev_uevent,
2351};
2352
2353static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2354 char *buf)
2355{
2356 struct kobject *top_kobj;
2357 struct kset *kset;
2358 struct kobj_uevent_env *env = NULL;
2359 int i;
2360 int len = 0;
2361 int retval;
2362
2363 /* search the kset, the device belongs to */
2364 top_kobj = &dev->kobj;
2365 while (!top_kobj->kset && top_kobj->parent)
2366 top_kobj = top_kobj->parent;
2367 if (!top_kobj->kset)
2368 goto out;
2369
2370 kset = top_kobj->kset;
2371 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2372 goto out;
2373
2374 /* respect filter */
2375 if (kset->uevent_ops && kset->uevent_ops->filter)
2376 if (!kset->uevent_ops->filter(kset, &dev->kobj))
2377 goto out;
2378
2379 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2380 if (!env)
2381 return -ENOMEM;
2382
2383 /* let the kset specific function add its keys */
2384 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
2385 if (retval)
2386 goto out;
2387
2388 /* copy keys to file */
2389 for (i = 0; i < env->envp_idx; i++)
2390 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2391out:
2392 kfree(env);
2393 return len;
2394}
2395
2396static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2397 const char *buf, size_t count)
2398{
2399 int rc;
2400
2401 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2402
2403 if (rc) {
2404 dev_err(dev, "uevent: failed to send synthetic uevent\n");
2405 return rc;
2406 }
2407
2408 return count;
2409}
2410static DEVICE_ATTR_RW(uevent);
2411
2412static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2413 char *buf)
2414{
2415 bool val;
2416
2417 device_lock(dev);
2418 val = !dev->offline;
2419 device_unlock(dev);
2420 return sysfs_emit(buf, "%u\n", val);
2421}
2422
2423static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2424 const char *buf, size_t count)
2425{
2426 bool val;
2427 int ret;
2428
2429 ret = strtobool(buf, &val);
2430 if (ret < 0)
2431 return ret;
2432
2433 ret = lock_device_hotplug_sysfs();
2434 if (ret)
2435 return ret;
2436
2437 ret = val ? device_online(dev) : device_offline(dev);
2438 unlock_device_hotplug();
2439 return ret < 0 ? ret : count;
2440}
2441static DEVICE_ATTR_RW(online);
2442
2443static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
2444 char *buf)
2445{
2446 const char *loc;
2447
2448 switch (dev->removable) {
2449 case DEVICE_REMOVABLE:
2450 loc = "removable";
2451 break;
2452 case DEVICE_FIXED:
2453 loc = "fixed";
2454 break;
2455 default:
2456 loc = "unknown";
2457 }
2458 return sysfs_emit(buf, "%s\n", loc);
2459}
2460static DEVICE_ATTR_RO(removable);
2461
2462int device_add_groups(struct device *dev, const struct attribute_group **groups)
2463{
2464 return sysfs_create_groups(&dev->kobj, groups);
2465}
2466EXPORT_SYMBOL_GPL(device_add_groups);
2467
2468void device_remove_groups(struct device *dev,
2469 const struct attribute_group **groups)
2470{
2471 sysfs_remove_groups(&dev->kobj, groups);
2472}
2473EXPORT_SYMBOL_GPL(device_remove_groups);
2474
2475union device_attr_group_devres {
2476 const struct attribute_group *group;
2477 const struct attribute_group **groups;
2478};
2479
2480static int devm_attr_group_match(struct device *dev, void *res, void *data)
2481{
2482 return ((union device_attr_group_devres *)res)->group == data;
2483}
2484
2485static void devm_attr_group_remove(struct device *dev, void *res)
2486{
2487 union device_attr_group_devres *devres = res;
2488 const struct attribute_group *group = devres->group;
2489
2490 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2491 sysfs_remove_group(&dev->kobj, group);
2492}
2493
2494static void devm_attr_groups_remove(struct device *dev, void *res)
2495{
2496 union device_attr_group_devres *devres = res;
2497 const struct attribute_group **groups = devres->groups;
2498
2499 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2500 sysfs_remove_groups(&dev->kobj, groups);
2501}
2502
2503/**
2504 * devm_device_add_group - given a device, create a managed attribute group
2505 * @dev: The device to create the group for
2506 * @grp: The attribute group to create
2507 *
2508 * This function creates a group for the first time. It will explicitly
2509 * warn and error if any of the attribute files being created already exist.
2510 *
2511 * Returns 0 on success or error code on failure.
2512 */
2513int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2514{
2515 union device_attr_group_devres *devres;
2516 int error;
2517
2518 devres = devres_alloc(devm_attr_group_remove,
2519 sizeof(*devres), GFP_KERNEL);
2520 if (!devres)
2521 return -ENOMEM;
2522
2523 error = sysfs_create_group(&dev->kobj, grp);
2524 if (error) {
2525 devres_free(devres);
2526 return error;
2527 }
2528
2529 devres->group = grp;
2530 devres_add(dev, devres);
2531 return 0;
2532}
2533EXPORT_SYMBOL_GPL(devm_device_add_group);
2534
2535/**
2536 * devm_device_remove_group: remove a managed group from a device
2537 * @dev: device to remove the group from
2538 * @grp: group to remove
2539 *
2540 * This function removes a group of attributes from a device. The attributes
2541 * previously have to have been created for this group, otherwise it will fail.
2542 */
2543void devm_device_remove_group(struct device *dev,
2544 const struct attribute_group *grp)
2545{
2546 WARN_ON(devres_release(dev, devm_attr_group_remove,
2547 devm_attr_group_match,
2548 /* cast away const */ (void *)grp));
2549}
2550EXPORT_SYMBOL_GPL(devm_device_remove_group);
2551
2552/**
2553 * devm_device_add_groups - create a bunch of managed attribute groups
2554 * @dev: The device to create the group for
2555 * @groups: The attribute groups to create, NULL terminated
2556 *
2557 * This function creates a bunch of managed attribute groups. If an error
2558 * occurs when creating a group, all previously created groups will be
2559 * removed, unwinding everything back to the original state when this
2560 * function was called. It will explicitly warn and error if any of the
2561 * attribute files being created already exist.
2562 *
2563 * Returns 0 on success or error code from sysfs_create_group on failure.
2564 */
2565int devm_device_add_groups(struct device *dev,
2566 const struct attribute_group **groups)
2567{
2568 union device_attr_group_devres *devres;
2569 int error;
2570
2571 devres = devres_alloc(devm_attr_groups_remove,
2572 sizeof(*devres), GFP_KERNEL);
2573 if (!devres)
2574 return -ENOMEM;
2575
2576 error = sysfs_create_groups(&dev->kobj, groups);
2577 if (error) {
2578 devres_free(devres);
2579 return error;
2580 }
2581
2582 devres->groups = groups;
2583 devres_add(dev, devres);
2584 return 0;
2585}
2586EXPORT_SYMBOL_GPL(devm_device_add_groups);
2587
2588/**
2589 * devm_device_remove_groups - remove a list of managed groups
2590 *
2591 * @dev: The device for the groups to be removed from
2592 * @groups: NULL terminated list of groups to be removed
2593 *
2594 * If groups is not NULL, remove the specified groups from the device.
2595 */
2596void devm_device_remove_groups(struct device *dev,
2597 const struct attribute_group **groups)
2598{
2599 WARN_ON(devres_release(dev, devm_attr_groups_remove,
2600 devm_attr_group_match,
2601 /* cast away const */ (void *)groups));
2602}
2603EXPORT_SYMBOL_GPL(devm_device_remove_groups);
2604
2605static int device_add_attrs(struct device *dev)
2606{
2607 struct class *class = dev->class;
2608 const struct device_type *type = dev->type;
2609 int error;
2610
2611 if (class) {
2612 error = device_add_groups(dev, class->dev_groups);
2613 if (error)
2614 return error;
2615 }
2616
2617 if (type) {
2618 error = device_add_groups(dev, type->groups);
2619 if (error)
2620 goto err_remove_class_groups;
2621 }
2622
2623 error = device_add_groups(dev, dev->groups);
2624 if (error)
2625 goto err_remove_type_groups;
2626
2627 if (device_supports_offline(dev) && !dev->offline_disabled) {
2628 error = device_create_file(dev, &dev_attr_online);
2629 if (error)
2630 goto err_remove_dev_groups;
2631 }
2632
2633 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2634 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2635 if (error)
2636 goto err_remove_dev_online;
2637 }
2638
2639 if (dev_removable_is_valid(dev)) {
2640 error = device_create_file(dev, &dev_attr_removable);
2641 if (error)
2642 goto err_remove_dev_waiting_for_supplier;
2643 }
2644
2645 return 0;
2646
2647 err_remove_dev_waiting_for_supplier:
2648 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2649 err_remove_dev_online:
2650 device_remove_file(dev, &dev_attr_online);
2651 err_remove_dev_groups:
2652 device_remove_groups(dev, dev->groups);
2653 err_remove_type_groups:
2654 if (type)
2655 device_remove_groups(dev, type->groups);
2656 err_remove_class_groups:
2657 if (class)
2658 device_remove_groups(dev, class->dev_groups);
2659
2660 return error;
2661}
2662
2663static void device_remove_attrs(struct device *dev)
2664{
2665 struct class *class = dev->class;
2666 const struct device_type *type = dev->type;
2667
2668 device_remove_file(dev, &dev_attr_removable);
2669 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2670 device_remove_file(dev, &dev_attr_online);
2671 device_remove_groups(dev, dev->groups);
2672
2673 if (type)
2674 device_remove_groups(dev, type->groups);
2675
2676 if (class)
2677 device_remove_groups(dev, class->dev_groups);
2678}
2679
2680static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2681 char *buf)
2682{
2683 return print_dev_t(buf, dev->devt);
2684}
2685static DEVICE_ATTR_RO(dev);
2686
2687/* /sys/devices/ */
2688struct kset *devices_kset;
2689
2690/**
2691 * devices_kset_move_before - Move device in the devices_kset's list.
2692 * @deva: Device to move.
2693 * @devb: Device @deva should come before.
2694 */
2695static void devices_kset_move_before(struct device *deva, struct device *devb)
2696{
2697 if (!devices_kset)
2698 return;
2699 pr_debug("devices_kset: Moving %s before %s\n",
2700 dev_name(deva), dev_name(devb));
2701 spin_lock(&devices_kset->list_lock);
2702 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2703 spin_unlock(&devices_kset->list_lock);
2704}
2705
2706/**
2707 * devices_kset_move_after - Move device in the devices_kset's list.
2708 * @deva: Device to move
2709 * @devb: Device @deva should come after.
2710 */
2711static void devices_kset_move_after(struct device *deva, struct device *devb)
2712{
2713 if (!devices_kset)
2714 return;
2715 pr_debug("devices_kset: Moving %s after %s\n",
2716 dev_name(deva), dev_name(devb));
2717 spin_lock(&devices_kset->list_lock);
2718 list_move(&deva->kobj.entry, &devb->kobj.entry);
2719 spin_unlock(&devices_kset->list_lock);
2720}
2721
2722/**
2723 * devices_kset_move_last - move the device to the end of devices_kset's list.
2724 * @dev: device to move
2725 */
2726void devices_kset_move_last(struct device *dev)
2727{
2728 if (!devices_kset)
2729 return;
2730 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2731 spin_lock(&devices_kset->list_lock);
2732 list_move_tail(&dev->kobj.entry, &devices_kset->list);
2733 spin_unlock(&devices_kset->list_lock);
2734}
2735
2736/**
2737 * device_create_file - create sysfs attribute file for device.
2738 * @dev: device.
2739 * @attr: device attribute descriptor.
2740 */
2741int device_create_file(struct device *dev,
2742 const struct device_attribute *attr)
2743{
2744 int error = 0;
2745
2746 if (dev) {
2747 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
2748 "Attribute %s: write permission without 'store'\n",
2749 attr->attr.name);
2750 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
2751 "Attribute %s: read permission without 'show'\n",
2752 attr->attr.name);
2753 error = sysfs_create_file(&dev->kobj, &attr->attr);
2754 }
2755
2756 return error;
2757}
2758EXPORT_SYMBOL_GPL(device_create_file);
2759
2760/**
2761 * device_remove_file - remove sysfs attribute file.
2762 * @dev: device.
2763 * @attr: device attribute descriptor.
2764 */
2765void device_remove_file(struct device *dev,
2766 const struct device_attribute *attr)
2767{
2768 if (dev)
2769 sysfs_remove_file(&dev->kobj, &attr->attr);
2770}
2771EXPORT_SYMBOL_GPL(device_remove_file);
2772
2773/**
2774 * device_remove_file_self - remove sysfs attribute file from its own method.
2775 * @dev: device.
2776 * @attr: device attribute descriptor.
2777 *
2778 * See kernfs_remove_self() for details.
2779 */
2780bool device_remove_file_self(struct device *dev,
2781 const struct device_attribute *attr)
2782{
2783 if (dev)
2784 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
2785 else
2786 return false;
2787}
2788EXPORT_SYMBOL_GPL(device_remove_file_self);
2789
2790/**
2791 * device_create_bin_file - create sysfs binary attribute file for device.
2792 * @dev: device.
2793 * @attr: device binary attribute descriptor.
2794 */
2795int device_create_bin_file(struct device *dev,
2796 const struct bin_attribute *attr)
2797{
2798 int error = -EINVAL;
2799 if (dev)
2800 error = sysfs_create_bin_file(&dev->kobj, attr);
2801 return error;
2802}
2803EXPORT_SYMBOL_GPL(device_create_bin_file);
2804
2805/**
2806 * device_remove_bin_file - remove sysfs binary attribute file
2807 * @dev: device.
2808 * @attr: device binary attribute descriptor.
2809 */
2810void device_remove_bin_file(struct device *dev,
2811 const struct bin_attribute *attr)
2812{
2813 if (dev)
2814 sysfs_remove_bin_file(&dev->kobj, attr);
2815}
2816EXPORT_SYMBOL_GPL(device_remove_bin_file);
2817
2818static void klist_children_get(struct klist_node *n)
2819{
2820 struct device_private *p = to_device_private_parent(n);
2821 struct device *dev = p->device;
2822
2823 get_device(dev);
2824}
2825
2826static void klist_children_put(struct klist_node *n)
2827{
2828 struct device_private *p = to_device_private_parent(n);
2829 struct device *dev = p->device;
2830
2831 put_device(dev);
2832}
2833
2834/**
2835 * device_initialize - init device structure.
2836 * @dev: device.
2837 *
2838 * This prepares the device for use by other layers by initializing
2839 * its fields.
2840 * It is the first half of device_register(), if called by
2841 * that function, though it can also be called separately, so one
2842 * may use @dev's fields. In particular, get_device()/put_device()
2843 * may be used for reference counting of @dev after calling this
2844 * function.
2845 *
2846 * All fields in @dev must be initialized by the caller to 0, except
2847 * for those explicitly set to some other value. The simplest
2848 * approach is to use kzalloc() to allocate the structure containing
2849 * @dev.
2850 *
2851 * NOTE: Use put_device() to give up your reference instead of freeing
2852 * @dev directly once you have called this function.
2853 */
2854void device_initialize(struct device *dev)
2855{
2856 dev->kobj.kset = devices_kset;
2857 kobject_init(&dev->kobj, &device_ktype);
2858 INIT_LIST_HEAD(&dev->dma_pools);
2859 mutex_init(&dev->mutex);
2860#ifdef CONFIG_PROVE_LOCKING
2861 mutex_init(&dev->lockdep_mutex);
2862#endif
2863 lockdep_set_novalidate_class(&dev->mutex);
2864 spin_lock_init(&dev->devres_lock);
2865 INIT_LIST_HEAD(&dev->devres_head);
2866 device_pm_init(dev);
2867 set_dev_node(dev, -1);
2868#ifdef CONFIG_GENERIC_MSI_IRQ
2869 raw_spin_lock_init(&dev->msi_lock);
2870 INIT_LIST_HEAD(&dev->msi_list);
2871#endif
2872 INIT_LIST_HEAD(&dev->links.consumers);
2873 INIT_LIST_HEAD(&dev->links.suppliers);
2874 INIT_LIST_HEAD(&dev->links.defer_sync);
2875 dev->links.status = DL_DEV_NO_DRIVER;
2876#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
2877 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
2878 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
2879 dev->dma_coherent = dma_default_coherent;
2880#endif
2881}
2882EXPORT_SYMBOL_GPL(device_initialize);
2883
2884struct kobject *virtual_device_parent(struct device *dev)
2885{
2886 static struct kobject *virtual_dir = NULL;
2887
2888 if (!virtual_dir)
2889 virtual_dir = kobject_create_and_add("virtual",
2890 &devices_kset->kobj);
2891
2892 return virtual_dir;
2893}
2894
2895struct class_dir {
2896 struct kobject kobj;
2897 struct class *class;
2898};
2899
2900#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
2901
2902static void class_dir_release(struct kobject *kobj)
2903{
2904 struct class_dir *dir = to_class_dir(kobj);
2905 kfree(dir);
2906}
2907
2908static const
2909struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
2910{
2911 struct class_dir *dir = to_class_dir(kobj);
2912 return dir->class->ns_type;
2913}
2914
2915static struct kobj_type class_dir_ktype = {
2916 .release = class_dir_release,
2917 .sysfs_ops = &kobj_sysfs_ops,
2918 .child_ns_type = class_dir_child_ns_type
2919};
2920
2921static struct kobject *
2922class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
2923{
2924 struct class_dir *dir;
2925 int retval;
2926
2927 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
2928 if (!dir)
2929 return ERR_PTR(-ENOMEM);
2930
2931 dir->class = class;
2932 kobject_init(&dir->kobj, &class_dir_ktype);
2933
2934 dir->kobj.kset = &class->p->glue_dirs;
2935
2936 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
2937 if (retval < 0) {
2938 kobject_put(&dir->kobj);
2939 return ERR_PTR(retval);
2940 }
2941 return &dir->kobj;
2942}
2943
2944static DEFINE_MUTEX(gdp_mutex);
2945
2946static struct kobject *get_device_parent(struct device *dev,
2947 struct device *parent)
2948{
2949 if (dev->class) {
2950 struct kobject *kobj = NULL;
2951 struct kobject *parent_kobj;
2952 struct kobject *k;
2953
2954#ifdef CONFIG_BLOCK
2955 /* block disks show up in /sys/block */
2956 if (sysfs_deprecated && dev->class == &block_class) {
2957 if (parent && parent->class == &block_class)
2958 return &parent->kobj;
2959 return &block_class.p->subsys.kobj;
2960 }
2961#endif
2962
2963 /*
2964 * If we have no parent, we live in "virtual".
2965 * Class-devices with a non class-device as parent, live
2966 * in a "glue" directory to prevent namespace collisions.
2967 */
2968 if (parent == NULL)
2969 parent_kobj = virtual_device_parent(dev);
2970 else if (parent->class && !dev->class->ns_type)
2971 return &parent->kobj;
2972 else
2973 parent_kobj = &parent->kobj;
2974
2975 mutex_lock(&gdp_mutex);
2976
2977 /* find our class-directory at the parent and reference it */
2978 spin_lock(&dev->class->p->glue_dirs.list_lock);
2979 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
2980 if (k->parent == parent_kobj) {
2981 kobj = kobject_get(k);
2982 break;
2983 }
2984 spin_unlock(&dev->class->p->glue_dirs.list_lock);
2985 if (kobj) {
2986 mutex_unlock(&gdp_mutex);
2987 return kobj;
2988 }
2989
2990 /* or create a new class-directory at the parent device */
2991 k = class_dir_create_and_add(dev->class, parent_kobj);
2992 /* do not emit an uevent for this simple "glue" directory */
2993 mutex_unlock(&gdp_mutex);
2994 return k;
2995 }
2996
2997 /* subsystems can specify a default root directory for their devices */
2998 if (!parent && dev->bus && dev->bus->dev_root)
2999 return &dev->bus->dev_root->kobj;
3000
3001 if (parent)
3002 return &parent->kobj;
3003 return NULL;
3004}
3005
3006static inline bool live_in_glue_dir(struct kobject *kobj,
3007 struct device *dev)
3008{
3009 if (!kobj || !dev->class ||
3010 kobj->kset != &dev->class->p->glue_dirs)
3011 return false;
3012 return true;
3013}
3014
3015static inline struct kobject *get_glue_dir(struct device *dev)
3016{
3017 return dev->kobj.parent;
3018}
3019
3020/*
3021 * make sure cleaning up dir as the last step, we need to make
3022 * sure .release handler of kobject is run with holding the
3023 * global lock
3024 */
3025static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
3026{
3027 unsigned int ref;
3028
3029 /* see if we live in a "glue" directory */
3030 if (!live_in_glue_dir(glue_dir, dev))
3031 return;
3032
3033 mutex_lock(&gdp_mutex);
3034 /**
3035 * There is a race condition between removing glue directory
3036 * and adding a new device under the glue directory.
3037 *
3038 * CPU1: CPU2:
3039 *
3040 * device_add()
3041 * get_device_parent()
3042 * class_dir_create_and_add()
3043 * kobject_add_internal()
3044 * create_dir() // create glue_dir
3045 *
3046 * device_add()
3047 * get_device_parent()
3048 * kobject_get() // get glue_dir
3049 *
3050 * device_del()
3051 * cleanup_glue_dir()
3052 * kobject_del(glue_dir)
3053 *
3054 * kobject_add()
3055 * kobject_add_internal()
3056 * create_dir() // in glue_dir
3057 * sysfs_create_dir_ns()
3058 * kernfs_create_dir_ns(sd)
3059 *
3060 * sysfs_remove_dir() // glue_dir->sd=NULL
3061 * sysfs_put() // free glue_dir->sd
3062 *
3063 * // sd is freed
3064 * kernfs_new_node(sd)
3065 * kernfs_get(glue_dir)
3066 * kernfs_add_one()
3067 * kernfs_put()
3068 *
3069 * Before CPU1 remove last child device under glue dir, if CPU2 add
3070 * a new device under glue dir, the glue_dir kobject reference count
3071 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3072 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3073 * and sysfs_put(). This result in glue_dir->sd is freed.
3074 *
3075 * Then the CPU2 will see a stale "empty" but still potentially used
3076 * glue dir around in kernfs_new_node().
3077 *
3078 * In order to avoid this happening, we also should make sure that
3079 * kernfs_node for glue_dir is released in CPU1 only when refcount
3080 * for glue_dir kobj is 1.
3081 */
3082 ref = kref_read(&glue_dir->kref);
3083 if (!kobject_has_children(glue_dir) && !--ref)
3084 kobject_del(glue_dir);
3085 kobject_put(glue_dir);
3086 mutex_unlock(&gdp_mutex);
3087}
3088
3089static int device_add_class_symlinks(struct device *dev)
3090{
3091 struct device_node *of_node = dev_of_node(dev);
3092 int error;
3093
3094 if (of_node) {
3095 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3096 if (error)
3097 dev_warn(dev, "Error %d creating of_node link\n",error);
3098 /* An error here doesn't warrant bringing down the device */
3099 }
3100
3101 if (!dev->class)
3102 return 0;
3103
3104 error = sysfs_create_link(&dev->kobj,
3105 &dev->class->p->subsys.kobj,
3106 "subsystem");
3107 if (error)
3108 goto out_devnode;
3109
3110 if (dev->parent && device_is_not_partition(dev)) {
3111 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3112 "device");
3113 if (error)
3114 goto out_subsys;
3115 }
3116
3117#ifdef CONFIG_BLOCK
3118 /* /sys/block has directories and does not need symlinks */
3119 if (sysfs_deprecated && dev->class == &block_class)
3120 return 0;
3121#endif
3122
3123 /* link in the class directory pointing to the device */
3124 error = sysfs_create_link(&dev->class->p->subsys.kobj,
3125 &dev->kobj, dev_name(dev));
3126 if (error)
3127 goto out_device;
3128
3129 return 0;
3130
3131out_device:
3132 sysfs_remove_link(&dev->kobj, "device");
3133
3134out_subsys:
3135 sysfs_remove_link(&dev->kobj, "subsystem");
3136out_devnode:
3137 sysfs_remove_link(&dev->kobj, "of_node");
3138 return error;
3139}
3140
3141static void device_remove_class_symlinks(struct device *dev)
3142{
3143 if (dev_of_node(dev))
3144 sysfs_remove_link(&dev->kobj, "of_node");
3145
3146 if (!dev->class)
3147 return;
3148
3149 if (dev->parent && device_is_not_partition(dev))
3150 sysfs_remove_link(&dev->kobj, "device");
3151 sysfs_remove_link(&dev->kobj, "subsystem");
3152#ifdef CONFIG_BLOCK
3153 if (sysfs_deprecated && dev->class == &block_class)
3154 return;
3155#endif
3156 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
3157}
3158
3159/**
3160 * dev_set_name - set a device name
3161 * @dev: device
3162 * @fmt: format string for the device's name
3163 */
3164int dev_set_name(struct device *dev, const char *fmt, ...)
3165{
3166 va_list vargs;
3167 int err;
3168
3169 va_start(vargs, fmt);
3170 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3171 va_end(vargs);
3172 return err;
3173}
3174EXPORT_SYMBOL_GPL(dev_set_name);
3175
3176/**
3177 * device_to_dev_kobj - select a /sys/dev/ directory for the device
3178 * @dev: device
3179 *
3180 * By default we select char/ for new entries. Setting class->dev_obj
3181 * to NULL prevents an entry from being created. class->dev_kobj must
3182 * be set (or cleared) before any devices are registered to the class
3183 * otherwise device_create_sys_dev_entry() and
3184 * device_remove_sys_dev_entry() will disagree about the presence of
3185 * the link.
3186 */
3187static struct kobject *device_to_dev_kobj(struct device *dev)
3188{
3189 struct kobject *kobj;
3190
3191 if (dev->class)
3192 kobj = dev->class->dev_kobj;
3193 else
3194 kobj = sysfs_dev_char_kobj;
3195
3196 return kobj;
3197}
3198
3199static int device_create_sys_dev_entry(struct device *dev)
3200{
3201 struct kobject *kobj = device_to_dev_kobj(dev);
3202 int error = 0;
3203 char devt_str[15];
3204
3205 if (kobj) {
3206 format_dev_t(devt_str, dev->devt);
3207 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3208 }
3209
3210 return error;
3211}
3212
3213static void device_remove_sys_dev_entry(struct device *dev)
3214{
3215 struct kobject *kobj = device_to_dev_kobj(dev);
3216 char devt_str[15];
3217
3218 if (kobj) {
3219 format_dev_t(devt_str, dev->devt);
3220 sysfs_remove_link(kobj, devt_str);
3221 }
3222}
3223
3224static int device_private_init(struct device *dev)
3225{
3226 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3227 if (!dev->p)
3228 return -ENOMEM;
3229 dev->p->device = dev;
3230 klist_init(&dev->p->klist_children, klist_children_get,
3231 klist_children_put);
3232 INIT_LIST_HEAD(&dev->p->deferred_probe);
3233 return 0;
3234}
3235
3236/**
3237 * device_add - add device to device hierarchy.
3238 * @dev: device.
3239 *
3240 * This is part 2 of device_register(), though may be called
3241 * separately _iff_ device_initialize() has been called separately.
3242 *
3243 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3244 * to the global and sibling lists for the device, then
3245 * adds it to the other relevant subsystems of the driver model.
3246 *
3247 * Do not call this routine or device_register() more than once for
3248 * any device structure. The driver model core is not designed to work
3249 * with devices that get unregistered and then spring back to life.
3250 * (Among other things, it's very hard to guarantee that all references
3251 * to the previous incarnation of @dev have been dropped.) Allocate
3252 * and register a fresh new struct device instead.
3253 *
3254 * NOTE: _Never_ directly free @dev after calling this function, even
3255 * if it returned an error! Always use put_device() to give up your
3256 * reference instead.
3257 *
3258 * Rule of thumb is: if device_add() succeeds, you should call
3259 * device_del() when you want to get rid of it. If device_add() has
3260 * *not* succeeded, use *only* put_device() to drop the reference
3261 * count.
3262 */
3263int device_add(struct device *dev)
3264{
3265 struct device *parent;
3266 struct kobject *kobj;
3267 struct class_interface *class_intf;
3268 int error = -EINVAL;
3269 struct kobject *glue_dir = NULL;
3270
3271 dev = get_device(dev);
3272 if (!dev)
3273 goto done;
3274
3275 if (!dev->p) {
3276 error = device_private_init(dev);
3277 if (error)
3278 goto done;
3279 }
3280
3281 /*
3282 * for statically allocated devices, which should all be converted
3283 * some day, we need to initialize the name. We prevent reading back
3284 * the name, and force the use of dev_name()
3285 */
3286 if (dev->init_name) {
3287 dev_set_name(dev, "%s", dev->init_name);
3288 dev->init_name = NULL;
3289 }
3290
3291 /* subsystems can specify simple device enumeration */
3292 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
3293 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3294
3295 if (!dev_name(dev)) {
3296 error = -EINVAL;
3297 goto name_error;
3298 }
3299
3300 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3301
3302 parent = get_device(dev->parent);
3303 kobj = get_device_parent(dev, parent);
3304 if (IS_ERR(kobj)) {
3305 error = PTR_ERR(kobj);
3306 goto parent_error;
3307 }
3308 if (kobj)
3309 dev->kobj.parent = kobj;
3310
3311 /* use parent numa_node */
3312 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3313 set_dev_node(dev, dev_to_node(parent));
3314
3315 /* first, register with generic layer. */
3316 /* we require the name to be set before, and pass NULL */
3317 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3318 if (error) {
3319 glue_dir = get_glue_dir(dev);
3320 goto Error;
3321 }
3322
3323 /* notify platform of device entry */
3324 error = device_platform_notify(dev, KOBJ_ADD);
3325 if (error)
3326 goto platform_error;
3327
3328 error = device_create_file(dev, &dev_attr_uevent);
3329 if (error)
3330 goto attrError;
3331
3332 error = device_add_class_symlinks(dev);
3333 if (error)
3334 goto SymlinkError;
3335 error = device_add_attrs(dev);
3336 if (error)
3337 goto AttrsError;
3338 error = bus_add_device(dev);
3339 if (error)
3340 goto BusError;
3341 error = dpm_sysfs_add(dev);
3342 if (error)
3343 goto DPMError;
3344 device_pm_add(dev);
3345
3346 if (MAJOR(dev->devt)) {
3347 error = device_create_file(dev, &dev_attr_dev);
3348 if (error)
3349 goto DevAttrError;
3350
3351 error = device_create_sys_dev_entry(dev);
3352 if (error)
3353 goto SysEntryError;
3354
3355 devtmpfs_create_node(dev);
3356 }
3357
3358 /* Notify clients of device addition. This call must come
3359 * after dpm_sysfs_add() and before kobject_uevent().
3360 */
3361 if (dev->bus)
3362 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3363 BUS_NOTIFY_ADD_DEVICE, dev);
3364
3365 kobject_uevent(&dev->kobj, KOBJ_ADD);
3366
3367 /*
3368 * Check if any of the other devices (consumers) have been waiting for
3369 * this device (supplier) to be added so that they can create a device
3370 * link to it.
3371 *
3372 * This needs to happen after device_pm_add() because device_link_add()
3373 * requires the supplier be registered before it's called.
3374 *
3375 * But this also needs to happen before bus_probe_device() to make sure
3376 * waiting consumers can link to it before the driver is bound to the
3377 * device and the driver sync_state callback is called for this device.
3378 */
3379 if (dev->fwnode && !dev->fwnode->dev) {
3380 dev->fwnode->dev = dev;
3381 fw_devlink_link_device(dev);
3382 }
3383
3384 bus_probe_device(dev);
3385
3386 /*
3387 * If all driver registration is done and a newly added device doesn't
3388 * match with any driver, don't block its consumers from probing in
3389 * case the consumer device is able to operate without this supplier.
3390 */
3391 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3392 fw_devlink_unblock_consumers(dev);
3393
3394 if (parent)
3395 klist_add_tail(&dev->p->knode_parent,
3396 &parent->p->klist_children);
3397
3398 if (dev->class) {
3399 mutex_lock(&dev->class->p->mutex);
3400 /* tie the class to the device */
3401 klist_add_tail(&dev->p->knode_class,
3402 &dev->class->p->klist_devices);
3403
3404 /* notify any interfaces that the device is here */
3405 list_for_each_entry(class_intf,
3406 &dev->class->p->interfaces, node)
3407 if (class_intf->add_dev)
3408 class_intf->add_dev(dev, class_intf);
3409 mutex_unlock(&dev->class->p->mutex);
3410 }
3411done:
3412 put_device(dev);
3413 return error;
3414 SysEntryError:
3415 if (MAJOR(dev->devt))
3416 device_remove_file(dev, &dev_attr_dev);
3417 DevAttrError:
3418 device_pm_remove(dev);
3419 dpm_sysfs_remove(dev);
3420 DPMError:
3421 bus_remove_device(dev);
3422 BusError:
3423 device_remove_attrs(dev);
3424 AttrsError:
3425 device_remove_class_symlinks(dev);
3426 SymlinkError:
3427 device_remove_file(dev, &dev_attr_uevent);
3428 attrError:
3429 device_platform_notify(dev, KOBJ_REMOVE);
3430platform_error:
3431 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3432 glue_dir = get_glue_dir(dev);
3433 kobject_del(&dev->kobj);
3434 Error:
3435 cleanup_glue_dir(dev, glue_dir);
3436parent_error:
3437 put_device(parent);
3438name_error:
3439 kfree(dev->p);
3440 dev->p = NULL;
3441 goto done;
3442}
3443EXPORT_SYMBOL_GPL(device_add);
3444
3445/**
3446 * device_register - register a device with the system.
3447 * @dev: pointer to the device structure
3448 *
3449 * This happens in two clean steps - initialize the device
3450 * and add it to the system. The two steps can be called
3451 * separately, but this is the easiest and most common.
3452 * I.e. you should only call the two helpers separately if
3453 * have a clearly defined need to use and refcount the device
3454 * before it is added to the hierarchy.
3455 *
3456 * For more information, see the kerneldoc for device_initialize()
3457 * and device_add().
3458 *
3459 * NOTE: _Never_ directly free @dev after calling this function, even
3460 * if it returned an error! Always use put_device() to give up the
3461 * reference initialized in this function instead.
3462 */
3463int device_register(struct device *dev)
3464{
3465 device_initialize(dev);
3466 return device_add(dev);
3467}
3468EXPORT_SYMBOL_GPL(device_register);
3469
3470/**
3471 * get_device - increment reference count for device.
3472 * @dev: device.
3473 *
3474 * This simply forwards the call to kobject_get(), though
3475 * we do take care to provide for the case that we get a NULL
3476 * pointer passed in.
3477 */
3478struct device *get_device(struct device *dev)
3479{
3480 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3481}
3482EXPORT_SYMBOL_GPL(get_device);
3483
3484/**
3485 * put_device - decrement reference count.
3486 * @dev: device in question.
3487 */
3488void put_device(struct device *dev)
3489{
3490 /* might_sleep(); */
3491 if (dev)
3492 kobject_put(&dev->kobj);
3493}
3494EXPORT_SYMBOL_GPL(put_device);
3495
3496bool kill_device(struct device *dev)
3497{
3498 /*
3499 * Require the device lock and set the "dead" flag to guarantee that
3500 * the update behavior is consistent with the other bitfields near
3501 * it and that we cannot have an asynchronous probe routine trying
3502 * to run while we are tearing out the bus/class/sysfs from
3503 * underneath the device.
3504 */
3505 device_lock_assert(dev);
3506
3507 if (dev->p->dead)
3508 return false;
3509 dev->p->dead = true;
3510 return true;
3511}
3512EXPORT_SYMBOL_GPL(kill_device);
3513
3514/**
3515 * device_del - delete device from system.
3516 * @dev: device.
3517 *
3518 * This is the first part of the device unregistration
3519 * sequence. This removes the device from the lists we control
3520 * from here, has it removed from the other driver model
3521 * subsystems it was added to in device_add(), and removes it
3522 * from the kobject hierarchy.
3523 *
3524 * NOTE: this should be called manually _iff_ device_add() was
3525 * also called manually.
3526 */
3527void device_del(struct device *dev)
3528{
3529 struct device *parent = dev->parent;
3530 struct kobject *glue_dir = NULL;
3531 struct class_interface *class_intf;
3532 unsigned int noio_flag;
3533
3534 device_lock(dev);
3535 kill_device(dev);
3536 device_unlock(dev);
3537
3538 if (dev->fwnode && dev->fwnode->dev == dev)
3539 dev->fwnode->dev = NULL;
3540
3541 /* Notify clients of device removal. This call must come
3542 * before dpm_sysfs_remove().
3543 */
3544 noio_flag = memalloc_noio_save();
3545 if (dev->bus)
3546 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3547 BUS_NOTIFY_DEL_DEVICE, dev);
3548
3549 dpm_sysfs_remove(dev);
3550 if (parent)
3551 klist_del(&dev->p->knode_parent);
3552 if (MAJOR(dev->devt)) {
3553 devtmpfs_delete_node(dev);
3554 device_remove_sys_dev_entry(dev);
3555 device_remove_file(dev, &dev_attr_dev);
3556 }
3557 if (dev->class) {
3558 device_remove_class_symlinks(dev);
3559
3560 mutex_lock(&dev->class->p->mutex);
3561 /* notify any interfaces that the device is now gone */
3562 list_for_each_entry(class_intf,
3563 &dev->class->p->interfaces, node)
3564 if (class_intf->remove_dev)
3565 class_intf->remove_dev(dev, class_intf);
3566 /* remove the device from the class list */
3567 klist_del(&dev->p->knode_class);
3568 mutex_unlock(&dev->class->p->mutex);
3569 }
3570 device_remove_file(dev, &dev_attr_uevent);
3571 device_remove_attrs(dev);
3572 bus_remove_device(dev);
3573 device_pm_remove(dev);
3574 driver_deferred_probe_del(dev);
3575 device_platform_notify(dev, KOBJ_REMOVE);
3576 device_remove_properties(dev);
3577 device_links_purge(dev);
3578
3579 if (dev->bus)
3580 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3581 BUS_NOTIFY_REMOVED_DEVICE, dev);
3582 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3583 glue_dir = get_glue_dir(dev);
3584 kobject_del(&dev->kobj);
3585 cleanup_glue_dir(dev, glue_dir);
3586 memalloc_noio_restore(noio_flag);
3587 put_device(parent);
3588}
3589EXPORT_SYMBOL_GPL(device_del);
3590
3591/**
3592 * device_unregister - unregister device from system.
3593 * @dev: device going away.
3594 *
3595 * We do this in two parts, like we do device_register(). First,
3596 * we remove it from all the subsystems with device_del(), then
3597 * we decrement the reference count via put_device(). If that
3598 * is the final reference count, the device will be cleaned up
3599 * via device_release() above. Otherwise, the structure will
3600 * stick around until the final reference to the device is dropped.
3601 */
3602void device_unregister(struct device *dev)
3603{
3604 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3605 device_del(dev);
3606 put_device(dev);
3607}
3608EXPORT_SYMBOL_GPL(device_unregister);
3609
3610static struct device *prev_device(struct klist_iter *i)
3611{
3612 struct klist_node *n = klist_prev(i);
3613 struct device *dev = NULL;
3614 struct device_private *p;
3615
3616 if (n) {
3617 p = to_device_private_parent(n);
3618 dev = p->device;
3619 }
3620 return dev;
3621}
3622
3623static struct device *next_device(struct klist_iter *i)
3624{
3625 struct klist_node *n = klist_next(i);
3626 struct device *dev = NULL;
3627 struct device_private *p;
3628
3629 if (n) {
3630 p = to_device_private_parent(n);
3631 dev = p->device;
3632 }
3633 return dev;
3634}
3635
3636/**
3637 * device_get_devnode - path of device node file
3638 * @dev: device
3639 * @mode: returned file access mode
3640 * @uid: returned file owner
3641 * @gid: returned file group
3642 * @tmp: possibly allocated string
3643 *
3644 * Return the relative path of a possible device node.
3645 * Non-default names may need to allocate a memory to compose
3646 * a name. This memory is returned in tmp and needs to be
3647 * freed by the caller.
3648 */
3649const char *device_get_devnode(struct device *dev,
3650 umode_t *mode, kuid_t *uid, kgid_t *gid,
3651 const char **tmp)
3652{
3653 char *s;
3654
3655 *tmp = NULL;
3656
3657 /* the device type may provide a specific name */
3658 if (dev->type && dev->type->devnode)
3659 *tmp = dev->type->devnode(dev, mode, uid, gid);
3660 if (*tmp)
3661 return *tmp;
3662
3663 /* the class may provide a specific name */
3664 if (dev->class && dev->class->devnode)
3665 *tmp = dev->class->devnode(dev, mode);
3666 if (*tmp)
3667 return *tmp;
3668
3669 /* return name without allocation, tmp == NULL */
3670 if (strchr(dev_name(dev), '!') == NULL)
3671 return dev_name(dev);
3672
3673 /* replace '!' in the name with '/' */
3674 s = kstrdup(dev_name(dev), GFP_KERNEL);
3675 if (!s)
3676 return NULL;
3677 strreplace(s, '!', '/');
3678 return *tmp = s;
3679}
3680
3681/**
3682 * device_for_each_child - device child iterator.
3683 * @parent: parent struct device.
3684 * @fn: function to be called for each device.
3685 * @data: data for the callback.
3686 *
3687 * Iterate over @parent's child devices, and call @fn for each,
3688 * passing it @data.
3689 *
3690 * We check the return of @fn each time. If it returns anything
3691 * other than 0, we break out and return that value.
3692 */
3693int device_for_each_child(struct device *parent, void *data,
3694 int (*fn)(struct device *dev, void *data))
3695{
3696 struct klist_iter i;
3697 struct device *child;
3698 int error = 0;
3699
3700 if (!parent->p)
3701 return 0;
3702
3703 klist_iter_init(&parent->p->klist_children, &i);
3704 while (!error && (child = next_device(&i)))
3705 error = fn(child, data);
3706 klist_iter_exit(&i);
3707 return error;
3708}
3709EXPORT_SYMBOL_GPL(device_for_each_child);
3710
3711/**
3712 * device_for_each_child_reverse - device child iterator in reversed order.
3713 * @parent: parent struct device.
3714 * @fn: function to be called for each device.
3715 * @data: data for the callback.
3716 *
3717 * Iterate over @parent's child devices, and call @fn for each,
3718 * passing it @data.
3719 *
3720 * We check the return of @fn each time. If it returns anything
3721 * other than 0, we break out and return that value.
3722 */
3723int device_for_each_child_reverse(struct device *parent, void *data,
3724 int (*fn)(struct device *dev, void *data))
3725{
3726 struct klist_iter i;
3727 struct device *child;
3728 int error = 0;
3729
3730 if (!parent->p)
3731 return 0;
3732
3733 klist_iter_init(&parent->p->klist_children, &i);
3734 while ((child = prev_device(&i)) && !error)
3735 error = fn(child, data);
3736 klist_iter_exit(&i);
3737 return error;
3738}
3739EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
3740
3741/**
3742 * device_find_child - device iterator for locating a particular device.
3743 * @parent: parent struct device
3744 * @match: Callback function to check device
3745 * @data: Data to pass to match function
3746 *
3747 * This is similar to the device_for_each_child() function above, but it
3748 * returns a reference to a device that is 'found' for later use, as
3749 * determined by the @match callback.
3750 *
3751 * The callback should return 0 if the device doesn't match and non-zero
3752 * if it does. If the callback returns non-zero and a reference to the
3753 * current device can be obtained, this function will return to the caller
3754 * and not iterate over any more devices.
3755 *
3756 * NOTE: you will need to drop the reference with put_device() after use.
3757 */
3758struct device *device_find_child(struct device *parent, void *data,
3759 int (*match)(struct device *dev, void *data))
3760{
3761 struct klist_iter i;
3762 struct device *child;
3763
3764 if (!parent)
3765 return NULL;
3766
3767 klist_iter_init(&parent->p->klist_children, &i);
3768 while ((child = next_device(&i)))
3769 if (match(child, data) && get_device(child))
3770 break;
3771 klist_iter_exit(&i);
3772 return child;
3773}
3774EXPORT_SYMBOL_GPL(device_find_child);
3775
3776/**
3777 * device_find_child_by_name - device iterator for locating a child device.
3778 * @parent: parent struct device
3779 * @name: name of the child device
3780 *
3781 * This is similar to the device_find_child() function above, but it
3782 * returns a reference to a device that has the name @name.
3783 *
3784 * NOTE: you will need to drop the reference with put_device() after use.
3785 */
3786struct device *device_find_child_by_name(struct device *parent,
3787 const char *name)
3788{
3789 struct klist_iter i;
3790 struct device *child;
3791
3792 if (!parent)
3793 return NULL;
3794
3795 klist_iter_init(&parent->p->klist_children, &i);
3796 while ((child = next_device(&i)))
3797 if (sysfs_streq(dev_name(child), name) && get_device(child))
3798 break;
3799 klist_iter_exit(&i);
3800 return child;
3801}
3802EXPORT_SYMBOL_GPL(device_find_child_by_name);
3803
3804int __init devices_init(void)
3805{
3806 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
3807 if (!devices_kset)
3808 return -ENOMEM;
3809 dev_kobj = kobject_create_and_add("dev", NULL);
3810 if (!dev_kobj)
3811 goto dev_kobj_err;
3812 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
3813 if (!sysfs_dev_block_kobj)
3814 goto block_kobj_err;
3815 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
3816 if (!sysfs_dev_char_kobj)
3817 goto char_kobj_err;
3818
3819 return 0;
3820
3821 char_kobj_err:
3822 kobject_put(sysfs_dev_block_kobj);
3823 block_kobj_err:
3824 kobject_put(dev_kobj);
3825 dev_kobj_err:
3826 kset_unregister(devices_kset);
3827 return -ENOMEM;
3828}
3829
3830static int device_check_offline(struct device *dev, void *not_used)
3831{
3832 int ret;
3833
3834 ret = device_for_each_child(dev, NULL, device_check_offline);
3835 if (ret)
3836 return ret;
3837
3838 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
3839}
3840
3841/**
3842 * device_offline - Prepare the device for hot-removal.
3843 * @dev: Device to be put offline.
3844 *
3845 * Execute the device bus type's .offline() callback, if present, to prepare
3846 * the device for a subsequent hot-removal. If that succeeds, the device must
3847 * not be used until either it is removed or its bus type's .online() callback
3848 * is executed.
3849 *
3850 * Call under device_hotplug_lock.
3851 */
3852int device_offline(struct device *dev)
3853{
3854 int ret;
3855
3856 if (dev->offline_disabled)
3857 return -EPERM;
3858
3859 ret = device_for_each_child(dev, NULL, device_check_offline);
3860 if (ret)
3861 return ret;
3862
3863 device_lock(dev);
3864 if (device_supports_offline(dev)) {
3865 if (dev->offline) {
3866 ret = 1;
3867 } else {
3868 ret = dev->bus->offline(dev);
3869 if (!ret) {
3870 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
3871 dev->offline = true;
3872 }
3873 }
3874 }
3875 device_unlock(dev);
3876
3877 return ret;
3878}
3879
3880/**
3881 * device_online - Put the device back online after successful device_offline().
3882 * @dev: Device to be put back online.
3883 *
3884 * If device_offline() has been successfully executed for @dev, but the device
3885 * has not been removed subsequently, execute its bus type's .online() callback
3886 * to indicate that the device can be used again.
3887 *
3888 * Call under device_hotplug_lock.
3889 */
3890int device_online(struct device *dev)
3891{
3892 int ret = 0;
3893
3894 device_lock(dev);
3895 if (device_supports_offline(dev)) {
3896 if (dev->offline) {
3897 ret = dev->bus->online(dev);
3898 if (!ret) {
3899 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
3900 dev->offline = false;
3901 }
3902 } else {
3903 ret = 1;
3904 }
3905 }
3906 device_unlock(dev);
3907
3908 return ret;
3909}
3910
3911struct root_device {
3912 struct device dev;
3913 struct module *owner;
3914};
3915
3916static inline struct root_device *to_root_device(struct device *d)
3917{
3918 return container_of(d, struct root_device, dev);
3919}
3920
3921static void root_device_release(struct device *dev)
3922{
3923 kfree(to_root_device(dev));
3924}
3925
3926/**
3927 * __root_device_register - allocate and register a root device
3928 * @name: root device name
3929 * @owner: owner module of the root device, usually THIS_MODULE
3930 *
3931 * This function allocates a root device and registers it
3932 * using device_register(). In order to free the returned
3933 * device, use root_device_unregister().
3934 *
3935 * Root devices are dummy devices which allow other devices
3936 * to be grouped under /sys/devices. Use this function to
3937 * allocate a root device and then use it as the parent of
3938 * any device which should appear under /sys/devices/{name}
3939 *
3940 * The /sys/devices/{name} directory will also contain a
3941 * 'module' symlink which points to the @owner directory
3942 * in sysfs.
3943 *
3944 * Returns &struct device pointer on success, or ERR_PTR() on error.
3945 *
3946 * Note: You probably want to use root_device_register().
3947 */
3948struct device *__root_device_register(const char *name, struct module *owner)
3949{
3950 struct root_device *root;
3951 int err = -ENOMEM;
3952
3953 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
3954 if (!root)
3955 return ERR_PTR(err);
3956
3957 err = dev_set_name(&root->dev, "%s", name);
3958 if (err) {
3959 kfree(root);
3960 return ERR_PTR(err);
3961 }
3962
3963 root->dev.release = root_device_release;
3964
3965 err = device_register(&root->dev);
3966 if (err) {
3967 put_device(&root->dev);
3968 return ERR_PTR(err);
3969 }
3970
3971#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
3972 if (owner) {
3973 struct module_kobject *mk = &owner->mkobj;
3974
3975 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
3976 if (err) {
3977 device_unregister(&root->dev);
3978 return ERR_PTR(err);
3979 }
3980 root->owner = owner;
3981 }
3982#endif
3983
3984 return &root->dev;
3985}
3986EXPORT_SYMBOL_GPL(__root_device_register);
3987
3988/**
3989 * root_device_unregister - unregister and free a root device
3990 * @dev: device going away
3991 *
3992 * This function unregisters and cleans up a device that was created by
3993 * root_device_register().
3994 */
3995void root_device_unregister(struct device *dev)
3996{
3997 struct root_device *root = to_root_device(dev);
3998
3999 if (root->owner)
4000 sysfs_remove_link(&root->dev.kobj, "module");
4001
4002 device_unregister(dev);
4003}
4004EXPORT_SYMBOL_GPL(root_device_unregister);
4005
4006
4007static void device_create_release(struct device *dev)
4008{
4009 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
4010 kfree(dev);
4011}
4012
4013static __printf(6, 0) struct device *
4014device_create_groups_vargs(struct class *class, struct device *parent,
4015 dev_t devt, void *drvdata,
4016 const struct attribute_group **groups,
4017 const char *fmt, va_list args)
4018{
4019 struct device *dev = NULL;
4020 int retval = -ENODEV;
4021
4022 if (class == NULL || IS_ERR(class))
4023 goto error;
4024
4025 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4026 if (!dev) {
4027 retval = -ENOMEM;
4028 goto error;
4029 }
4030
4031 device_initialize(dev);
4032 dev->devt = devt;
4033 dev->class = class;
4034 dev->parent = parent;
4035 dev->groups = groups;
4036 dev->release = device_create_release;
4037 dev_set_drvdata(dev, drvdata);
4038
4039 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
4040 if (retval)
4041 goto error;
4042
4043 retval = device_add(dev);
4044 if (retval)
4045 goto error;
4046
4047 return dev;
4048
4049error:
4050 put_device(dev);
4051 return ERR_PTR(retval);
4052}
4053
4054/**
4055 * device_create - creates a device and registers it with sysfs
4056 * @class: pointer to the struct class that this device should be registered to
4057 * @parent: pointer to the parent struct device of this new device, if any
4058 * @devt: the dev_t for the char device to be added
4059 * @drvdata: the data to be added to the device for callbacks
4060 * @fmt: string for the device's name
4061 *
4062 * This function can be used by char device classes. A struct device
4063 * will be created in sysfs, registered to the specified class.
4064 *
4065 * A "dev" file will be created, showing the dev_t for the device, if
4066 * the dev_t is not 0,0.
4067 * If a pointer to a parent struct device is passed in, the newly created
4068 * struct device will be a child of that device in sysfs.
4069 * The pointer to the struct device will be returned from the call.
4070 * Any further sysfs files that might be required can be created using this
4071 * pointer.
4072 *
4073 * Returns &struct device pointer on success, or ERR_PTR() on error.
4074 *
4075 * Note: the struct class passed to this function must have previously
4076 * been created with a call to class_create().
4077 */
4078struct device *device_create(struct class *class, struct device *parent,
4079 dev_t devt, void *drvdata, const char *fmt, ...)
4080{
4081 va_list vargs;
4082 struct device *dev;
4083
4084 va_start(vargs, fmt);
4085 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4086 fmt, vargs);
4087 va_end(vargs);
4088 return dev;
4089}
4090EXPORT_SYMBOL_GPL(device_create);
4091
4092/**
4093 * device_create_with_groups - creates a device and registers it with sysfs
4094 * @class: pointer to the struct class that this device should be registered to
4095 * @parent: pointer to the parent struct device of this new device, if any
4096 * @devt: the dev_t for the char device to be added
4097 * @drvdata: the data to be added to the device for callbacks
4098 * @groups: NULL-terminated list of attribute groups to be created
4099 * @fmt: string for the device's name
4100 *
4101 * This function can be used by char device classes. A struct device
4102 * will be created in sysfs, registered to the specified class.
4103 * Additional attributes specified in the groups parameter will also
4104 * be created automatically.
4105 *
4106 * A "dev" file will be created, showing the dev_t for the device, if
4107 * the dev_t is not 0,0.
4108 * If a pointer to a parent struct device is passed in, the newly created
4109 * struct device will be a child of that device in sysfs.
4110 * The pointer to the struct device will be returned from the call.
4111 * Any further sysfs files that might be required can be created using this
4112 * pointer.
4113 *
4114 * Returns &struct device pointer on success, or ERR_PTR() on error.
4115 *
4116 * Note: the struct class passed to this function must have previously
4117 * been created with a call to class_create().
4118 */
4119struct device *device_create_with_groups(struct class *class,
4120 struct device *parent, dev_t devt,
4121 void *drvdata,
4122 const struct attribute_group **groups,
4123 const char *fmt, ...)
4124{
4125 va_list vargs;
4126 struct device *dev;
4127
4128 va_start(vargs, fmt);
4129 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4130 fmt, vargs);
4131 va_end(vargs);
4132 return dev;
4133}
4134EXPORT_SYMBOL_GPL(device_create_with_groups);
4135
4136/**
4137 * device_destroy - removes a device that was created with device_create()
4138 * @class: pointer to the struct class that this device was registered with
4139 * @devt: the dev_t of the device that was previously registered
4140 *
4141 * This call unregisters and cleans up a device that was created with a
4142 * call to device_create().
4143 */
4144void device_destroy(struct class *class, dev_t devt)
4145{
4146 struct device *dev;
4147
4148 dev = class_find_device_by_devt(class, devt);
4149 if (dev) {
4150 put_device(dev);
4151 device_unregister(dev);
4152 }
4153}
4154EXPORT_SYMBOL_GPL(device_destroy);
4155
4156/**
4157 * device_rename - renames a device
4158 * @dev: the pointer to the struct device to be renamed
4159 * @new_name: the new name of the device
4160 *
4161 * It is the responsibility of the caller to provide mutual
4162 * exclusion between two different calls of device_rename
4163 * on the same device to ensure that new_name is valid and
4164 * won't conflict with other devices.
4165 *
4166 * Note: Don't call this function. Currently, the networking layer calls this
4167 * function, but that will change. The following text from Kay Sievers offers
4168 * some insight:
4169 *
4170 * Renaming devices is racy at many levels, symlinks and other stuff are not
4171 * replaced atomically, and you get a "move" uevent, but it's not easy to
4172 * connect the event to the old and new device. Device nodes are not renamed at
4173 * all, there isn't even support for that in the kernel now.
4174 *
4175 * In the meantime, during renaming, your target name might be taken by another
4176 * driver, creating conflicts. Or the old name is taken directly after you
4177 * renamed it -- then you get events for the same DEVPATH, before you even see
4178 * the "move" event. It's just a mess, and nothing new should ever rely on
4179 * kernel device renaming. Besides that, it's not even implemented now for
4180 * other things than (driver-core wise very simple) network devices.
4181 *
4182 * We are currently about to change network renaming in udev to completely
4183 * disallow renaming of devices in the same namespace as the kernel uses,
4184 * because we can't solve the problems properly, that arise with swapping names
4185 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
4186 * be allowed to some other name than eth[0-9]*, for the aforementioned
4187 * reasons.
4188 *
4189 * Make up a "real" name in the driver before you register anything, or add
4190 * some other attributes for userspace to find the device, or use udev to add
4191 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4192 * don't even want to get into that and try to implement the missing pieces in
4193 * the core. We really have other pieces to fix in the driver core mess. :)
4194 */
4195int device_rename(struct device *dev, const char *new_name)
4196{
4197 struct kobject *kobj = &dev->kobj;
4198 char *old_device_name = NULL;
4199 int error;
4200
4201 dev = get_device(dev);
4202 if (!dev)
4203 return -EINVAL;
4204
4205 dev_dbg(dev, "renaming to %s\n", new_name);
4206
4207 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4208 if (!old_device_name) {
4209 error = -ENOMEM;
4210 goto out;
4211 }
4212
4213 if (dev->class) {
4214 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
4215 kobj, old_device_name,
4216 new_name, kobject_namespace(kobj));
4217 if (error)
4218 goto out;
4219 }
4220
4221 error = kobject_rename(kobj, new_name);
4222 if (error)
4223 goto out;
4224
4225out:
4226 put_device(dev);
4227
4228 kfree(old_device_name);
4229
4230 return error;
4231}
4232EXPORT_SYMBOL_GPL(device_rename);
4233
4234static int device_move_class_links(struct device *dev,
4235 struct device *old_parent,
4236 struct device *new_parent)
4237{
4238 int error = 0;
4239
4240 if (old_parent)
4241 sysfs_remove_link(&dev->kobj, "device");
4242 if (new_parent)
4243 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4244 "device");
4245 return error;
4246}
4247
4248/**
4249 * device_move - moves a device to a new parent
4250 * @dev: the pointer to the struct device to be moved
4251 * @new_parent: the new parent of the device (can be NULL)
4252 * @dpm_order: how to reorder the dpm_list
4253 */
4254int device_move(struct device *dev, struct device *new_parent,
4255 enum dpm_order dpm_order)
4256{
4257 int error;
4258 struct device *old_parent;
4259 struct kobject *new_parent_kobj;
4260
4261 dev = get_device(dev);
4262 if (!dev)
4263 return -EINVAL;
4264
4265 device_pm_lock();
4266 new_parent = get_device(new_parent);
4267 new_parent_kobj = get_device_parent(dev, new_parent);
4268 if (IS_ERR(new_parent_kobj)) {
4269 error = PTR_ERR(new_parent_kobj);
4270 put_device(new_parent);
4271 goto out;
4272 }
4273
4274 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4275 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4276 error = kobject_move(&dev->kobj, new_parent_kobj);
4277 if (error) {
4278 cleanup_glue_dir(dev, new_parent_kobj);
4279 put_device(new_parent);
4280 goto out;
4281 }
4282 old_parent = dev->parent;
4283 dev->parent = new_parent;
4284 if (old_parent)
4285 klist_remove(&dev->p->knode_parent);
4286 if (new_parent) {
4287 klist_add_tail(&dev->p->knode_parent,
4288 &new_parent->p->klist_children);
4289 set_dev_node(dev, dev_to_node(new_parent));
4290 }
4291
4292 if (dev->class) {
4293 error = device_move_class_links(dev, old_parent, new_parent);
4294 if (error) {
4295 /* We ignore errors on cleanup since we're hosed anyway... */
4296 device_move_class_links(dev, new_parent, old_parent);
4297 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4298 if (new_parent)
4299 klist_remove(&dev->p->knode_parent);
4300 dev->parent = old_parent;
4301 if (old_parent) {
4302 klist_add_tail(&dev->p->knode_parent,
4303 &old_parent->p->klist_children);
4304 set_dev_node(dev, dev_to_node(old_parent));
4305 }
4306 }
4307 cleanup_glue_dir(dev, new_parent_kobj);
4308 put_device(new_parent);
4309 goto out;
4310 }
4311 }
4312 switch (dpm_order) {
4313 case DPM_ORDER_NONE:
4314 break;
4315 case DPM_ORDER_DEV_AFTER_PARENT:
4316 device_pm_move_after(dev, new_parent);
4317 devices_kset_move_after(dev, new_parent);
4318 break;
4319 case DPM_ORDER_PARENT_BEFORE_DEV:
4320 device_pm_move_before(new_parent, dev);
4321 devices_kset_move_before(new_parent, dev);
4322 break;
4323 case DPM_ORDER_DEV_LAST:
4324 device_pm_move_last(dev);
4325 devices_kset_move_last(dev);
4326 break;
4327 }
4328
4329 put_device(old_parent);
4330out:
4331 device_pm_unlock();
4332 put_device(dev);
4333 return error;
4334}
4335EXPORT_SYMBOL_GPL(device_move);
4336
4337static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4338 kgid_t kgid)
4339{
4340 struct kobject *kobj = &dev->kobj;
4341 struct class *class = dev->class;
4342 const struct device_type *type = dev->type;
4343 int error;
4344
4345 if (class) {
4346 /*
4347 * Change the device groups of the device class for @dev to
4348 * @kuid/@kgid.
4349 */
4350 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4351 kgid);
4352 if (error)
4353 return error;
4354 }
4355
4356 if (type) {
4357 /*
4358 * Change the device groups of the device type for @dev to
4359 * @kuid/@kgid.
4360 */
4361 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4362 kgid);
4363 if (error)
4364 return error;
4365 }
4366
4367 /* Change the device groups of @dev to @kuid/@kgid. */
4368 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4369 if (error)
4370 return error;
4371
4372 if (device_supports_offline(dev) && !dev->offline_disabled) {
4373 /* Change online device attributes of @dev to @kuid/@kgid. */
4374 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4375 kuid, kgid);
4376 if (error)
4377 return error;
4378 }
4379
4380 return 0;
4381}
4382
4383/**
4384 * device_change_owner - change the owner of an existing device.
4385 * @dev: device.
4386 * @kuid: new owner's kuid
4387 * @kgid: new owner's kgid
4388 *
4389 * This changes the owner of @dev and its corresponding sysfs entries to
4390 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4391 * core.
4392 *
4393 * Returns 0 on success or error code on failure.
4394 */
4395int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4396{
4397 int error;
4398 struct kobject *kobj = &dev->kobj;
4399
4400 dev = get_device(dev);
4401 if (!dev)
4402 return -EINVAL;
4403
4404 /*
4405 * Change the kobject and the default attributes and groups of the
4406 * ktype associated with it to @kuid/@kgid.
4407 */
4408 error = sysfs_change_owner(kobj, kuid, kgid);
4409 if (error)
4410 goto out;
4411
4412 /*
4413 * Change the uevent file for @dev to the new owner. The uevent file
4414 * was created in a separate step when @dev got added and we mirror
4415 * that step here.
4416 */
4417 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4418 kgid);
4419 if (error)
4420 goto out;
4421
4422 /*
4423 * Change the device groups, the device groups associated with the
4424 * device class, and the groups associated with the device type of @dev
4425 * to @kuid/@kgid.
4426 */
4427 error = device_attrs_change_owner(dev, kuid, kgid);
4428 if (error)
4429 goto out;
4430
4431 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4432 if (error)
4433 goto out;
4434
4435#ifdef CONFIG_BLOCK
4436 if (sysfs_deprecated && dev->class == &block_class)
4437 goto out;
4438#endif
4439
4440 /*
4441 * Change the owner of the symlink located in the class directory of
4442 * the device class associated with @dev which points to the actual
4443 * directory entry for @dev to @kuid/@kgid. This ensures that the
4444 * symlink shows the same permissions as its target.
4445 */
4446 error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj,
4447 dev_name(dev), kuid, kgid);
4448 if (error)
4449 goto out;
4450
4451out:
4452 put_device(dev);
4453 return error;
4454}
4455EXPORT_SYMBOL_GPL(device_change_owner);
4456
4457/**
4458 * device_shutdown - call ->shutdown() on each device to shutdown.
4459 */
4460void device_shutdown(void)
4461{
4462 struct device *dev, *parent;
4463
4464 wait_for_device_probe();
4465 device_block_probing();
4466
4467 cpufreq_suspend();
4468
4469 spin_lock(&devices_kset->list_lock);
4470 /*
4471 * Walk the devices list backward, shutting down each in turn.
4472 * Beware that device unplug events may also start pulling
4473 * devices offline, even as the system is shutting down.
4474 */
4475 while (!list_empty(&devices_kset->list)) {
4476 dev = list_entry(devices_kset->list.prev, struct device,
4477 kobj.entry);
4478
4479 /*
4480 * hold reference count of device's parent to
4481 * prevent it from being freed because parent's
4482 * lock is to be held
4483 */
4484 parent = get_device(dev->parent);
4485 get_device(dev);
4486 /*
4487 * Make sure the device is off the kset list, in the
4488 * event that dev->*->shutdown() doesn't remove it.
4489 */
4490 list_del_init(&dev->kobj.entry);
4491 spin_unlock(&devices_kset->list_lock);
4492
4493 /* hold lock to avoid race with probe/release */
4494 if (parent)
4495 device_lock(parent);
4496 device_lock(dev);
4497
4498 /* Don't allow any more runtime suspends */
4499 pm_runtime_get_noresume(dev);
4500 pm_runtime_barrier(dev);
4501
4502 if (dev->class && dev->class->shutdown_pre) {
4503 if (initcall_debug)
4504 dev_info(dev, "shutdown_pre\n");
4505 dev->class->shutdown_pre(dev);
4506 }
4507 if (dev->bus && dev->bus->shutdown) {
4508 if (initcall_debug)
4509 dev_info(dev, "shutdown\n");
4510 dev->bus->shutdown(dev);
4511 } else if (dev->driver && dev->driver->shutdown) {
4512 if (initcall_debug)
4513 dev_info(dev, "shutdown\n");
4514 dev->driver->shutdown(dev);
4515 }
4516
4517 device_unlock(dev);
4518 if (parent)
4519 device_unlock(parent);
4520
4521 put_device(dev);
4522 put_device(parent);
4523
4524 spin_lock(&devices_kset->list_lock);
4525 }
4526 spin_unlock(&devices_kset->list_lock);
4527}
4528
4529/*
4530 * Device logging functions
4531 */
4532
4533#ifdef CONFIG_PRINTK
4534static void
4535set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4536{
4537 const char *subsys;
4538
4539 memset(dev_info, 0, sizeof(*dev_info));
4540
4541 if (dev->class)
4542 subsys = dev->class->name;
4543 else if (dev->bus)
4544 subsys = dev->bus->name;
4545 else
4546 return;
4547
4548 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
4549
4550 /*
4551 * Add device identifier DEVICE=:
4552 * b12:8 block dev_t
4553 * c127:3 char dev_t
4554 * n8 netdev ifindex
4555 * +sound:card0 subsystem:devname
4556 */
4557 if (MAJOR(dev->devt)) {
4558 char c;
4559
4560 if (strcmp(subsys, "block") == 0)
4561 c = 'b';
4562 else
4563 c = 'c';
4564
4565 snprintf(dev_info->device, sizeof(dev_info->device),
4566 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4567 } else if (strcmp(subsys, "net") == 0) {
4568 struct net_device *net = to_net_dev(dev);
4569
4570 snprintf(dev_info->device, sizeof(dev_info->device),
4571 "n%u", net->ifindex);
4572 } else {
4573 snprintf(dev_info->device, sizeof(dev_info->device),
4574 "+%s:%s", subsys, dev_name(dev));
4575 }
4576}
4577
4578int dev_vprintk_emit(int level, const struct device *dev,
4579 const char *fmt, va_list args)
4580{
4581 struct dev_printk_info dev_info;
4582
4583 set_dev_info(dev, &dev_info);
4584
4585 return vprintk_emit(0, level, &dev_info, fmt, args);
4586}
4587EXPORT_SYMBOL(dev_vprintk_emit);
4588
4589int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4590{
4591 va_list args;
4592 int r;
4593
4594 va_start(args, fmt);
4595
4596 r = dev_vprintk_emit(level, dev, fmt, args);
4597
4598 va_end(args);
4599
4600 return r;
4601}
4602EXPORT_SYMBOL(dev_printk_emit);
4603
4604static void __dev_printk(const char *level, const struct device *dev,
4605 struct va_format *vaf)
4606{
4607 if (dev)
4608 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4609 dev_driver_string(dev), dev_name(dev), vaf);
4610 else
4611 printk("%s(NULL device *): %pV", level, vaf);
4612}
4613
4614void dev_printk(const char *level, const struct device *dev,
4615 const char *fmt, ...)
4616{
4617 struct va_format vaf;
4618 va_list args;
4619
4620 va_start(args, fmt);
4621
4622 vaf.fmt = fmt;
4623 vaf.va = &args;
4624
4625 __dev_printk(level, dev, &vaf);
4626
4627 va_end(args);
4628}
4629EXPORT_SYMBOL(dev_printk);
4630
4631#define define_dev_printk_level(func, kern_level) \
4632void func(const struct device *dev, const char *fmt, ...) \
4633{ \
4634 struct va_format vaf; \
4635 va_list args; \
4636 \
4637 va_start(args, fmt); \
4638 \
4639 vaf.fmt = fmt; \
4640 vaf.va = &args; \
4641 \
4642 __dev_printk(kern_level, dev, &vaf); \
4643 \
4644 va_end(args); \
4645} \
4646EXPORT_SYMBOL(func);
4647
4648define_dev_printk_level(_dev_emerg, KERN_EMERG);
4649define_dev_printk_level(_dev_alert, KERN_ALERT);
4650define_dev_printk_level(_dev_crit, KERN_CRIT);
4651define_dev_printk_level(_dev_err, KERN_ERR);
4652define_dev_printk_level(_dev_warn, KERN_WARNING);
4653define_dev_printk_level(_dev_notice, KERN_NOTICE);
4654define_dev_printk_level(_dev_info, KERN_INFO);
4655
4656#endif
4657
4658/**
4659 * dev_err_probe - probe error check and log helper
4660 * @dev: the pointer to the struct device
4661 * @err: error value to test
4662 * @fmt: printf-style format string
4663 * @...: arguments as specified in the format string
4664 *
4665 * This helper implements common pattern present in probe functions for error
4666 * checking: print debug or error message depending if the error value is
4667 * -EPROBE_DEFER and propagate error upwards.
4668 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4669 * checked later by reading devices_deferred debugfs attribute.
4670 * It replaces code sequence::
4671 *
4672 * if (err != -EPROBE_DEFER)
4673 * dev_err(dev, ...);
4674 * else
4675 * dev_dbg(dev, ...);
4676 * return err;
4677 *
4678 * with::
4679 *
4680 * return dev_err_probe(dev, err, ...);
4681 *
4682 * Returns @err.
4683 *
4684 */
4685int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4686{
4687 struct va_format vaf;
4688 va_list args;
4689
4690 va_start(args, fmt);
4691 vaf.fmt = fmt;
4692 vaf.va = &args;
4693
4694 if (err != -EPROBE_DEFER) {
4695 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4696 } else {
4697 device_set_deferred_probe_reason(dev, &vaf);
4698 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4699 }
4700
4701 va_end(args);
4702
4703 return err;
4704}
4705EXPORT_SYMBOL_GPL(dev_err_probe);
4706
4707static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4708{
4709 return fwnode && !IS_ERR(fwnode->secondary);
4710}
4711
4712/**
4713 * set_primary_fwnode - Change the primary firmware node of a given device.
4714 * @dev: Device to handle.
4715 * @fwnode: New primary firmware node of the device.
4716 *
4717 * Set the device's firmware node pointer to @fwnode, but if a secondary
4718 * firmware node of the device is present, preserve it.
4719 *
4720 * Valid fwnode cases are:
4721 * - primary --> secondary --> -ENODEV
4722 * - primary --> NULL
4723 * - secondary --> -ENODEV
4724 * - NULL
4725 */
4726void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4727{
4728 struct device *parent = dev->parent;
4729 struct fwnode_handle *fn = dev->fwnode;
4730
4731 if (fwnode) {
4732 if (fwnode_is_primary(fn))
4733 fn = fn->secondary;
4734
4735 if (fn) {
4736 WARN_ON(fwnode->secondary);
4737 fwnode->secondary = fn;
4738 }
4739 dev->fwnode = fwnode;
4740 } else {
4741 if (fwnode_is_primary(fn)) {
4742 dev->fwnode = fn->secondary;
4743 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
4744 if (!(parent && fn == parent->fwnode))
4745 fn->secondary = NULL;
4746 } else {
4747 dev->fwnode = NULL;
4748 }
4749 }
4750}
4751EXPORT_SYMBOL_GPL(set_primary_fwnode);
4752
4753/**
4754 * set_secondary_fwnode - Change the secondary firmware node of a given device.
4755 * @dev: Device to handle.
4756 * @fwnode: New secondary firmware node of the device.
4757 *
4758 * If a primary firmware node of the device is present, set its secondary
4759 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
4760 * @fwnode.
4761 */
4762void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4763{
4764 if (fwnode)
4765 fwnode->secondary = ERR_PTR(-ENODEV);
4766
4767 if (fwnode_is_primary(dev->fwnode))
4768 dev->fwnode->secondary = fwnode;
4769 else
4770 dev->fwnode = fwnode;
4771}
4772EXPORT_SYMBOL_GPL(set_secondary_fwnode);
4773
4774/**
4775 * device_set_of_node_from_dev - reuse device-tree node of another device
4776 * @dev: device whose device-tree node is being set
4777 * @dev2: device whose device-tree node is being reused
4778 *
4779 * Takes another reference to the new device-tree node after first dropping
4780 * any reference held to the old node.
4781 */
4782void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
4783{
4784 of_node_put(dev->of_node);
4785 dev->of_node = of_node_get(dev2->of_node);
4786 dev->of_node_reused = true;
4787}
4788EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
4789
4790void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
4791{
4792 dev->fwnode = fwnode;
4793 dev->of_node = to_of_node(fwnode);
4794}
4795EXPORT_SYMBOL_GPL(device_set_node);
4796
4797int device_match_name(struct device *dev, const void *name)
4798{
4799 return sysfs_streq(dev_name(dev), name);
4800}
4801EXPORT_SYMBOL_GPL(device_match_name);
4802
4803int device_match_of_node(struct device *dev, const void *np)
4804{
4805 return dev->of_node == np;
4806}
4807EXPORT_SYMBOL_GPL(device_match_of_node);
4808
4809int device_match_fwnode(struct device *dev, const void *fwnode)
4810{
4811 return dev_fwnode(dev) == fwnode;
4812}
4813EXPORT_SYMBOL_GPL(device_match_fwnode);
4814
4815int device_match_devt(struct device *dev, const void *pdevt)
4816{
4817 return dev->devt == *(dev_t *)pdevt;
4818}
4819EXPORT_SYMBOL_GPL(device_match_devt);
4820
4821int device_match_acpi_dev(struct device *dev, const void *adev)
4822{
4823 return ACPI_COMPANION(dev) == adev;
4824}
4825EXPORT_SYMBOL(device_match_acpi_dev);
4826
4827int device_match_any(struct device *dev, const void *unused)
4828{
4829 return 1;
4830}
4831EXPORT_SYMBOL_GPL(device_match_any);