summaryrefslogtreecommitdiffstats
path: root/drivers/of/dynamic.c
blob: 888fdbc099920a7533d1df89a534db7b6908a9e0 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
/*
 * Support for dynamic device trees.
 *
 * On some platforms, the device tree can be manipulated at runtime.
 * The routines in this section support adding, removing and changing
 * device tree nodes.
 */

#define pr_fmt(fmt)	"OF: " fmt

#include <linux/of.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/proc_fs.h>

#include "of_private.h"

/**
 * of_node_get() - Increment refcount of a node
 * @node:	Node to inc refcount, NULL is supported to simplify writing of
 *		callers
 *
 * Returns node.
 */
struct device_node *of_node_get(struct device_node *node)
{
	if (node)
		kobject_get(&node->kobj);
	return node;
}
EXPORT_SYMBOL(of_node_get);

/**
 * of_node_put() - Decrement refcount of a node
 * @node:	Node to dec refcount, NULL is supported to simplify writing of
 *		callers
 */
void of_node_put(struct device_node *node)
{
	if (node)
		kobject_put(&node->kobj);
}
EXPORT_SYMBOL(of_node_put);

void __of_detach_node_sysfs(struct device_node *np)
{
	struct property *pp;

	if (!IS_ENABLED(CONFIG_SYSFS))
		return;

	BUG_ON(!of_node_is_initialized(np));
	if (!of_kset)
		return;

	/* only remove properties if on sysfs */
	if (of_node_is_attached(np)) {
		for_each_property_of_node(np, pp)
			__of_sysfs_remove_bin_file(np, pp);
		kobject_del(&np->kobj);
	}

	/* finally remove the kobj_init ref */
	of_node_put(np);
}

static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);

int of_reconfig_notifier_register(struct notifier_block *nb)
{
	return blocking_notifier_chain_register(&of_reconfig_chain, nb);
}
EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);

int of_reconfig_notifier_unregister(struct notifier_block *nb)
{
	return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
}
EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);

#ifdef DEBUG
const char *action_names[] = {
	[OF_RECONFIG_ATTACH_NODE] = "ATTACH_NODE",
	[OF_RECONFIG_DETACH_NODE] = "DETACH_NODE",
	[OF_RECONFIG_ADD_PROPERTY] = "ADD_PROPERTY",
	[OF_RECONFIG_REMOVE_PROPERTY] = "REMOVE_PROPERTY",
	[OF_RECONFIG_UPDATE_PROPERTY] = "UPDATE_PROPERTY",
};
#endif

int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
{
	int rc;
#ifdef DEBUG
	struct of_reconfig_data *pr = p;

	switch (action) {
	case OF_RECONFIG_ATTACH_NODE:
	case OF_RECONFIG_DETACH_NODE:
		pr_debug("notify %-15s %s\n", action_names[action],
			pr->dn->full_name);
		break;
	case OF_RECONFIG_ADD_PROPERTY:
	case OF_RECONFIG_REMOVE_PROPERTY:
	case OF_RECONFIG_UPDATE_PROPERTY:
		pr_debug("notify %-15s %s:%s\n", action_names[action],
			pr->dn->full_name, pr->prop->name);
		break;

	}
#endif
	rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
	return notifier_to_errno(rc);
}

/*
 * of_reconfig_get_state_change()	- Returns new state of device
 * @action	- action of the of notifier
 * @arg		- argument of the of notifier
 *
 * Returns the new state of a device based on the notifier used.
 * Returns 0 on device going from enabled to disabled, 1 on device
 * going from disabled to enabled and -1 on no change.
 */
int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr)
{
	struct property *prop, *old_prop = NULL;
	int is_status, status_state, old_status_state, prev_state, new_state;

	/* figure out if a device should be created or destroyed */
	switch (action) {
	case OF_RECONFIG_ATTACH_NODE:
	case OF_RECONFIG_DETACH_NODE:
		prop = of_find_property(pr->dn, "status", NULL);
		break;
	case OF_RECONFIG_ADD_PROPERTY:
	case OF_RECONFIG_REMOVE_PROPERTY:
		prop = pr->prop;
		break;
	case OF_RECONFIG_UPDATE_PROPERTY:
		prop = pr->prop;
		old_prop = pr->old_prop;
		break;
	default:
		return OF_RECONFIG_NO_CHANGE;
	}

	is_status = 0;
	status_state = -1;
	old_status_state = -1;
	prev_state = -1;
	new_state = -1;

	if (prop && !strcmp(prop->name, "status")) {
		is_status = 1;
		status_state = !strcmp(prop->value, "okay") ||
			       !strcmp(prop->value, "ok");
		if (old_prop)
			old_status_state = !strcmp(old_prop->value, "okay") ||
					   !strcmp(old_prop->value, "ok");
	}

	switch (action) {
	case OF_RECONFIG_ATTACH_NODE:
		prev_state = 0;
		/* -1 & 0 status either missing or okay */
		new_state = status_state != 0;
		break;
	case OF_RECONFIG_DETACH_NODE:
		/* -1 & 0 status either missing or okay */
		prev_state = status_state != 0;
		new_state = 0;
		break;
	case OF_RECONFIG_ADD_PROPERTY:
		if (is_status) {
			/* no status property -> enabled (legacy) */
			prev_state = 1;
			new_state = status_state;
		}
		break;
	case OF_RECONFIG_REMOVE_PROPERTY:
		if (is_status) {
			prev_state = status_state;
			/* no status property -> enabled (legacy) */
			new_state = 1;
		}
		break;
	case OF_RECONFIG_UPDATE_PROPERTY:
		if (is_status) {
			prev_state = old_status_state != 0;
			new_state = status_state != 0;
		}
		break;
	}

	if (prev_state == new_state)
		return OF_RECONFIG_NO_CHANGE;

	return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
}
EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);

int of_property_notify(int action, struct device_node *np,
		       struct property *prop, struct property *oldprop)
{
	struct of_reconfig_data pr;

	/* only call notifiers if the node is attached */
	if (!of_node_is_attached(np))
		return 0;

	pr.dn = np;
	pr.prop = prop;
	pr.old_prop = oldprop;
	return of_reconfig_notify(action, &pr);
}

void __of_attach_node(struct device_node *np)
{
	const __be32 *phandle;
	int sz;

	np->name = __of_get_property(np, "name", NULL) ? : "<NULL>";
	np->type = __of_get_property(np, "device_type", NULL) ? : "<NULL>";

	phandle = __of_get_property(np, "phandle", &sz);
	if (!phandle)
		phandle = __of_get_property(np, "linux,phandle", &sz);
	if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
		phandle = __of_get_property(np, "ibm,phandle", &sz);
	np->phandle = (phandle && (sz >= 4)) ? be32_to_cpup(phandle) : 0;

	np->child = NULL;
	np->sibling = np->parent->child;
	np->parent->child = np;
	of_node_clear_flag(np, OF_DETACHED);
}

/**
 * of_attach_node() - Plug a device node into the tree and global list.
 */
int of_attach_node(struct device_node *np)
{
	struct of_reconfig_data rd;
	unsigned long flags;

	memset(&rd, 0, sizeof(rd));
	rd.dn = np;

	mutex_lock(&of_mutex);
	raw_spin_lock_irqsave(&devtree_lock, flags);
	__of_attach_node(np);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);

	__of_attach_node_sysfs(np);
	mutex_unlock(&of_mutex);

	of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);

	return 0;
}

void __of_detach_node(struct device_node *np)
{
	struct device_node *parent;

	if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
		return;

	parent = np->parent;
	if (WARN_ON(!parent))
		return;

	if (parent->child == np)
		parent->child = np->sibling;
	else {
		struct device_node *prevsib;
		for (prevsib = np->parent->child;
		     prevsib->sibling != np;
		     prevsib = prevsib->sibling)
			;
		prevsib->sibling = np->sibling;
	}

	of_node_set_flag(np, OF_DETACHED);
}

/**
 * of_detach_node() - "Unplug" a node from the device tree.
 *
 * The caller must hold a reference to the node.  The memory associated with
 * the node is not freed until its refcount goes to zero.
 */
int of_detach_node(struct device_node *np)
{
	struct of_reconfig_data rd;
	unsigned long flags;
	int rc = 0;

	memset(&rd, 0, sizeof(rd));
	rd.dn = np;

	mutex_lock(&of_mutex);
	raw_spin_lock_irqsave(&devtree_lock, flags);
	__of_detach_node(np);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);

	__of_detach_node_sysfs(np);
	mutex_unlock(&of_mutex);

	of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);

	return rc;
}
EXPORT_SYMBOL_GPL(of_detach_node);

/**
 * of_node_release() - release a dynamically allocated node
 * @kref: kref element of the node to be released
 *
 * In of_node_put() this function is passed to kref_put() as the destructor.
 */
void of_node_release(struct kobject *kobj)
{
	struct device_node *node = kobj_to_device_node(kobj);
	struct property *prop = node->properties;

	/* We should never be releasing nodes that haven't been detached. */
	if (!of_node_check_flag(node, OF_DETACHED)) {
		pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name);
		dump_stack();
		return;
	}

	if (!of_node_check_flag(node, OF_DYNAMIC))
		return;

	while (prop) {
		struct property *next = prop->next;
		kfree(prop->name);
		kfree(prop->value);
		kfree(prop);
		prop = next;

		if (!prop) {
			prop = node->deadprops;
			node->deadprops = NULL;
		}
	}
	kfree(node->full_name);
	kfree(node->data);
	kfree(node);
}

/**
 * __of_prop_dup - Copy a property dynamically.
 * @prop:	Property to copy
 * @allocflags:	Allocation flags (typically pass GFP_KERNEL)
 *
 * Copy a property by dynamically allocating the memory of both the
 * property structure and the property name & contents. The property's
 * flags have the OF_DYNAMIC bit set so that we can differentiate between
 * dynamically allocated properties and not.
 * Returns the newly allocated property or NULL on out of memory error.
 */
struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
{
	struct property *new;

	new = kzalloc(sizeof(*new), allocflags);
	if (!new)
		return NULL;

	/*
	 * NOTE: There is no check for zero length value.
	 * In case of a boolean property, this will allocate a value
	 * of zero bytes. We do this to work around the use
	 * of of_get_property() calls on boolean values.
	 */
	new->name = kstrdup(prop->name, allocflags);
	new->value = kmemdup(prop->value, prop->length, allocflags);
	new->length = prop->length;
	if (!new->name || !new->value)
		goto err_free;

	/* mark the property as dynamic */
	of_property_set_flag(new, OF_DYNAMIC);

	return new;

 err_free:
	kfree(new->name);
	kfree(new->value);
	kfree(new);
	return NULL;
}

/**
 * __of_node_dup() - Duplicate or create an empty device node dynamically.
 * @fmt: Format string (plus vargs) for new full name of the device node
 *
 * Create an device tree node, either by duplicating an empty node or by allocating
 * an empty one suitable for further modification.  The node data are
 * dynamically allocated and all the node flags have the OF_DYNAMIC &
 * OF_DETACHED bits set. Returns the newly allocated node or NULL on out of
 * memory error.
 */
struct device_node *__of_node_dup(const struct device_node *np, const char *fmt, ...)
{
	va_list vargs;
	struct device_node *node;

	node = kzalloc(sizeof(*node), GFP_KERNEL);
	if (!node)
		return NULL;
	va_start(vargs, fmt);
	node->full_name = kvasprintf(GFP_KERNEL, fmt, vargs);
	va_end(vargs);
	if (!node->full_name) {
		kfree(node);
		return NULL;
	}

	of_node_set_flag(node, OF_DYNAMIC);
	of_node_set_flag(node, OF_DETACHED);
	of_node_init(node);

	/* Iterate over and duplicate all properties */
	if (np) {
		struct property *pp, *new_pp;
		for_each_property_of_node(np, pp) {
			new_pp = __of_prop_dup(pp, GFP_KERNEL);
			if (!new_pp)
				goto err_prop;
			if (__of_add_property(node, new_pp)) {
				kfree(new_pp->name);
				kfree(new_pp->value);
				kfree(new_pp);
				goto err_prop;
			}
		}
	}
	return node;

 err_prop:
	of_node_put(node); /* Frees the node and properties */
	return NULL;
}

static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
{
	of_node_put(ce->np);
	list_del(&ce->node);
	kfree(ce);
}

#ifdef DEBUG
static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
{
	switch (ce->action) {
	case OF_RECONFIG_ADD_PROPERTY:
	case OF_RECONFIG_REMOVE_PROPERTY:
	case OF_RECONFIG_UPDATE_PROPERTY:
		pr_debug("cset<%p> %-15s %s/%s\n", ce, action_names[ce->action],
			ce->np->full_name, ce->prop->name);
		break;
	case OF_RECONFIG_ATTACH_NODE:
	case OF_RECONFIG_DETACH_NODE:
		pr_debug("cset<%p> %-15s %s\n", ce, action_names[ce->action],
			ce->np->full_name);
		break;
	}
}
#else
static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
{
	/* empty */
}
#endif

static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
					  struct of_changeset_entry *rce)
{
	memcpy(rce, ce, sizeof(*rce));

	switch (ce->action) {
	case OF_RECONFIG_ATTACH_NODE:
		rce->action = OF_RECONFIG_DETACH_NODE;
		break;
	case OF_RECONFIG_DETACH_NODE:
		rce->action = OF_RECONFIG_ATTACH_NODE;
		break;
	case OF_RECONFIG_ADD_PROPERTY:
		rce->action = OF_RECONFIG_REMOVE_PROPERTY;
		break;
	case OF_RECONFIG_REMOVE_PROPERTY:
		rce->action = OF_RECONFIG_ADD_PROPERTY;
		break;
	case OF_RECONFIG_UPDATE_PROPERTY:
		rce->old_prop = ce->prop;
		rce->prop = ce->old_prop;
		/* update was used but original property did not exist */
		if (!rce->prop) {
			rce->action = OF_RECONFIG_REMOVE_PROPERTY;
			rce->prop = ce->prop;
		}
		break;
	}
}

static void __of_changeset_entry_notify(struct of_changeset_entry *ce, bool revert)
{
	struct of_reconfig_data rd;
	struct of_changeset_entry ce_inverted;
	int ret;

	if (revert) {
		__of_changeset_entry_invert(ce, &ce_inverted);
		ce = &ce_inverted;
	}

	switch (ce->action) {
	case OF_RECONFIG_ATTACH_NODE:
	case OF_RECONFIG_DETACH_NODE:
		memset(&rd, 0, sizeof(rd));
		rd.dn = ce->np;
		ret = of_reconfig_notify(ce->action, &rd);
		break;
	case OF_RECONFIG_ADD_PROPERTY:
	case OF_RECONFIG_REMOVE_PROPERTY:
	case OF_RECONFIG_UPDATE_PROPERTY:
		ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
		break;
	default:
		pr_err("invalid devicetree changeset action: %i\n",
			(int)ce->action);
		return;
	}

	if (ret)
		pr_err("changeset notifier error @%s\n", ce->np->full_name);
}

static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
{
	struct property *old_prop, **propp;
	unsigned long flags;
	int ret = 0;

	__of_changeset_entry_dump(ce);

	raw_spin_lock_irqsave(&devtree_lock, flags);
	switch (ce->action) {
	case OF_RECONFIG_ATTACH_NODE:
		__of_attach_node(ce->np);
		break;
	case OF_RECONFIG_DETACH_NODE:
		__of_detach_node(ce->np);
		break;
	case OF_RECONFIG_ADD_PROPERTY:
		/* If the property is in deadprops then it must be removed */
		for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
			if (*propp == ce->prop) {
				*propp = ce->prop->next;
				ce->prop->next = NULL;
				break;
			}
		}

		ret = __of_add_property(ce->np, ce->prop);
		if (ret) {
			pr_err("changeset: add_property failed @%s/%s\n",
				ce->np->full_name,
				ce->prop->name);
			break;
		}
		break;
	case OF_RECONFIG_REMOVE_PROPERTY:
		ret = __of_remove_property(ce->np, ce->prop);
		if (ret) {
			pr_err("changeset: remove_property failed @%s/%s\n",
				ce->np->full_name,
				ce->prop->name);
			break;
		}
		break;

	case OF_RECONFIG_UPDATE_PROPERTY:
		/* If the property is in deadprops then it must be removed */
		for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
			if (*propp == ce->prop) {
				*propp = ce->prop->next;
				ce->prop->next = NULL;
				break;
			}
		}

		ret = __of_update_property(ce->np, ce->prop, &old_prop);
		if (ret) {
			pr_err("changeset: update_property failed @%s/%s\n",
				ce->np->full_name,
				ce->prop->name);
			break;
		}
		break;
	default:
		ret = -EINVAL;
	}
	raw_spin_unlock_irqrestore(&devtree_lock, flags);

	if (ret)
		return ret;

	switch (ce->action) {
	case OF_RECONFIG_ATTACH_NODE:
		__of_attach_node_sysfs(ce->np);
		break;
	case OF_RECONFIG_DETACH_NODE:
		__of_detach_node_sysfs(ce->np);
		break;
	case OF_RECONFIG_ADD_PROPERTY:
		/* ignore duplicate names */
		__of_add_property_sysfs(ce->np, ce->prop);
		break;
	case OF_RECONFIG_REMOVE_PROPERTY:
		__of_remove_property_sysfs(ce->np, ce->prop);
		break;
	case OF_RECONFIG_UPDATE_PROPERTY:
		__of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
		break;
	}

	return 0;
}

static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
{
	struct of_changeset_entry ce_inverted;

	__of_changeset_entry_invert(ce, &ce_inverted);
	return __of_changeset_entry_apply(&ce_inverted);
}

/**
 * of_changeset_init - Initialize a changeset for use
 *
 * @ocs:	changeset pointer
 *
 * Initialize a changeset structure
 */
void of_changeset_init(struct of_changeset *ocs)
{
	memset(ocs, 0, sizeof(*ocs));
	INIT_LIST_HEAD(&ocs->entries);
}
EXPORT_SYMBOL_GPL(of_changeset_init);

/**
 * of_changeset_destroy - Destroy a changeset
 *
 * @ocs:	changeset pointer
 *
 * Destroys a changeset. Note that if a changeset is applied,
 * its changes to the tree cannot be reverted.
 */
void of_changeset_destroy(struct of_changeset *ocs)
{
	struct of_changeset_entry *ce, *cen;

	list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
		__of_changeset_entry_destroy(ce);
}
EXPORT_SYMBOL_GPL(of_changeset_destroy);

int __of_changeset_apply(struct of_changeset *ocs)
{
	struct of_changeset_entry *ce;
	int ret;

	/* perform the rest of the work */
	pr_debug("changeset: applying...\n");
	list_for_each_entry(ce, &ocs->entries, node) {
		ret = __of_changeset_entry_apply(ce);
		if (ret) {
			pr_err("Error applying changeset (%d)\n", ret);
			list_for_each_entry_continue_reverse(ce, &ocs->entries, node)
				__of_changeset_entry_revert(ce);
			return ret;
		}
	}
	pr_debug("changeset: applied, emitting notifiers.\n");

	/* drop the global lock while emitting notifiers */
	mutex_unlock(&of_mutex);
	list_for_each_entry(ce, &ocs->entries, node)
		__of_changeset_entry_notify(ce, 0);
	mutex_lock(&of_mutex);
	pr_debug("changeset: notifiers sent.\n");

	return 0;
}

/**
 * of_changeset_apply - Applies a changeset
 *
 * @ocs:	changeset pointer
 *
 * Applies a changeset to the live tree.
 * Any side-effects of live tree state changes are applied here on
 * success, like creation/destruction of devices and side-effects
 * like creation of sysfs properties and directories.
 * Returns 0 on success, a negative error value in case of an error.
 * On error the partially applied effects are reverted.
 */
int of_changeset_apply(struct of_changeset *ocs)
{
	int ret;

	mutex_lock(&of_mutex);
	ret = __of_changeset_apply(ocs);
	mutex_unlock(&of_mutex);

	return ret;
}
EXPORT_SYMBOL_GPL(of_changeset_apply);

int __of_changeset_revert(struct of_changeset *ocs)
{
	struct of_changeset_entry *ce;
	int ret;

	pr_debug("changeset: reverting...\n");
	list_for_each_entry_reverse(ce, &ocs->entries, node) {
		ret = __of_changeset_entry_revert(ce);
		if (ret) {
			pr_err("Error reverting changeset (%d)\n", ret);
			list_for_each_entry_continue(ce, &ocs->entries, node)
				__of_changeset_entry_apply(ce);
			return ret;
		}
	}
	pr_debug("changeset: reverted, emitting notifiers.\n");

	/* drop the global lock while emitting notifiers */
	mutex_unlock(&of_mutex);
	list_for_each_entry_reverse(ce, &ocs->entries, node)
		__of_changeset_entry_notify(ce, 1);
	mutex_lock(&of_mutex);
	pr_debug("changeset: notifiers sent.\n");

	return 0;
}

/**
 * of_changeset_revert - Reverts an applied changeset
 *
 * @ocs:	changeset pointer
 *
 * Reverts a changeset returning the state of the tree to what it
 * was before the application.
 * Any side-effects like creation/destruction of devices and
 * removal of sysfs properties and directories are applied.
 * Returns 0 on success, a negative error value in case of an error.
 */
int of_changeset_revert(struct of_changeset *ocs)
{
	int ret;

	mutex_lock(&of_mutex);
	ret = __of_changeset_revert(ocs);
	mutex_unlock(&of_mutex);

	return ret;
}
EXPORT_SYMBOL_GPL(of_changeset_revert);

/**
 * of_changeset_action - Perform a changeset action
 *
 * @ocs:	changeset pointer
 * @action:	action to perform
 * @np:		Pointer to device node
 * @prop:	Pointer to property
 *
 * On action being one of:
 * + OF_RECONFIG_ATTACH_NODE
 * + OF_RECONFIG_DETACH_NODE,
 * + OF_RECONFIG_ADD_PROPERTY
 * + OF_RECONFIG_REMOVE_PROPERTY,
 * + OF_RECONFIG_UPDATE_PROPERTY
 * Returns 0 on success, a negative error value in case of an error.
 */
int of_changeset_action(struct of_changeset *ocs, unsigned long action,
		struct device_node *np, struct property *prop)
{
	struct of_changeset_entry *ce;

	ce = kzalloc(sizeof(*ce), GFP_KERNEL);
	if (!ce)
		return -ENOMEM;

	/* get a reference to the node */
	ce->action = action;
	ce->np = of_node_get(np);
	ce->prop = prop;

	if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
		ce->old_prop = of_find_property(np, prop->name, NULL);

	/* add it to the list */
	list_add_tail(&ce->node, &ocs->entries);
	return 0;
}
EXPORT_SYMBOL_GPL(of_changeset_action);