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