1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Support for dynamic device trees.
  4 *
  5 * On some platforms, the device tree can be manipulated at runtime.
  6 * The routines in this section support adding, removing and changing
  7 * device tree nodes.
  8 */
  9
 10#define pr_fmt(fmt)	"OF: " fmt
 11
 12#include <linux/of.h>
 13#include <linux/spinlock.h>
 14#include <linux/slab.h>
 15#include <linux/string.h>
 16#include <linux/proc_fs.h>
 17
 18#include "of_private.h"
 19
 20static struct device_node *kobj_to_device_node(struct kobject *kobj)
 21{
 22	return container_of(kobj, struct device_node, kobj);
 23}
 24
 25/**
 26 * of_node_get() - Increment refcount of a node
 27 * @node:	Node to inc refcount, NULL is supported to simplify writing of
 28 *		callers
 29 *
 30 * Returns node.
 31 */
 32struct device_node *of_node_get(struct device_node *node)
 33{
 34	if (node)
 35		kobject_get(&node->kobj);
 36	return node;
 37}
 38EXPORT_SYMBOL(of_node_get);
 39
 40/**
 41 * of_node_put() - Decrement refcount of a node
 42 * @node:	Node to dec refcount, NULL is supported to simplify writing of
 43 *		callers
 44 */
 45void of_node_put(struct device_node *node)
 46{
 47	if (node)
 48		kobject_put(&node->kobj);
 49}
 50EXPORT_SYMBOL(of_node_put);
 51
 52static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
 53
 54int of_reconfig_notifier_register(struct notifier_block *nb)
 55{
 56	return blocking_notifier_chain_register(&of_reconfig_chain, nb);
 57}
 58EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
 59
 60int of_reconfig_notifier_unregister(struct notifier_block *nb)
 61{
 62	return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
 63}
 64EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
 65
 66#ifdef DEBUG
 67const char *action_names[] = {
 68	[OF_RECONFIG_ATTACH_NODE] = "ATTACH_NODE",
 69	[OF_RECONFIG_DETACH_NODE] = "DETACH_NODE",
 70	[OF_RECONFIG_ADD_PROPERTY] = "ADD_PROPERTY",
 71	[OF_RECONFIG_REMOVE_PROPERTY] = "REMOVE_PROPERTY",
 72	[OF_RECONFIG_UPDATE_PROPERTY] = "UPDATE_PROPERTY",
 73};
 74#endif
 75
 76int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
 77{
 78	int rc;
 79#ifdef DEBUG
 80	struct of_reconfig_data *pr = p;
 81
 82	switch (action) {
 83	case OF_RECONFIG_ATTACH_NODE:
 84	case OF_RECONFIG_DETACH_NODE:
 85		pr_debug("notify %-15s %pOF\n", action_names[action],
 86			pr->dn);
 87		break;
 88	case OF_RECONFIG_ADD_PROPERTY:
 89	case OF_RECONFIG_REMOVE_PROPERTY:
 90	case OF_RECONFIG_UPDATE_PROPERTY:
 91		pr_debug("notify %-15s %pOF:%s\n", action_names[action],
 92			pr->dn, pr->prop->name);
 93		break;
 94
 95	}
 96#endif
 97	rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
 98	return notifier_to_errno(rc);
 99}
100
101/*
102 * of_reconfig_get_state_change()	- Returns new state of device
103 * @action	- action of the of notifier
104 * @arg		- argument of the of notifier
105 *
106 * Returns the new state of a device based on the notifier used.
107 * Returns 0 on device going from enabled to disabled, 1 on device
108 * going from disabled to enabled and -1 on no change.
109 */
110int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr)
111{
112	struct property *prop, *old_prop = NULL;
113	int is_status, status_state, old_status_state, prev_state, new_state;
114
115	/* figure out if a device should be created or destroyed */
116	switch (action) {
117	case OF_RECONFIG_ATTACH_NODE:
118	case OF_RECONFIG_DETACH_NODE:
119		prop = of_find_property(pr->dn, "status", NULL);
120		break;
121	case OF_RECONFIG_ADD_PROPERTY:
122	case OF_RECONFIG_REMOVE_PROPERTY:
123		prop = pr->prop;
124		break;
125	case OF_RECONFIG_UPDATE_PROPERTY:
126		prop = pr->prop;
127		old_prop = pr->old_prop;
128		break;
129	default:
130		return OF_RECONFIG_NO_CHANGE;
131	}
132
133	is_status = 0;
134	status_state = -1;
135	old_status_state = -1;
136	prev_state = -1;
137	new_state = -1;
138
139	if (prop && !strcmp(prop->name, "status")) {
140		is_status = 1;
141		status_state = !strcmp(prop->value, "okay") ||
142			       !strcmp(prop->value, "ok");
143		if (old_prop)
144			old_status_state = !strcmp(old_prop->value, "okay") ||
145					   !strcmp(old_prop->value, "ok");
146	}
147
148	switch (action) {
149	case OF_RECONFIG_ATTACH_NODE:
150		prev_state = 0;
151		/* -1 & 0 status either missing or okay */
152		new_state = status_state != 0;
153		break;
154	case OF_RECONFIG_DETACH_NODE:
155		/* -1 & 0 status either missing or okay */
156		prev_state = status_state != 0;
157		new_state = 0;
158		break;
159	case OF_RECONFIG_ADD_PROPERTY:
160		if (is_status) {
161			/* no status property -> enabled (legacy) */
162			prev_state = 1;
163			new_state = status_state;
164		}
165		break;
166	case OF_RECONFIG_REMOVE_PROPERTY:
167		if (is_status) {
168			prev_state = status_state;
169			/* no status property -> enabled (legacy) */
170			new_state = 1;
171		}
172		break;
173	case OF_RECONFIG_UPDATE_PROPERTY:
174		if (is_status) {
175			prev_state = old_status_state != 0;
176			new_state = status_state != 0;
177		}
178		break;
179	}
180
181	if (prev_state == new_state)
182		return OF_RECONFIG_NO_CHANGE;
183
184	return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
185}
186EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
187
188int of_property_notify(int action, struct device_node *np,
189		       struct property *prop, struct property *oldprop)
190{
191	struct of_reconfig_data pr;
192
193	/* only call notifiers if the node is attached */
194	if (!of_node_is_attached(np))
195		return 0;
196
197	pr.dn = np;
198	pr.prop = prop;
199	pr.old_prop = oldprop;
200	return of_reconfig_notify(action, &pr);
201}
202
203static void __of_attach_node(struct device_node *np)
204{
205	const __be32 *phandle;
206	int sz;
207
208	if (!of_node_check_flag(np, OF_OVERLAY)) {
209		np->name = __of_get_property(np, "name", NULL);
210		if (!np->name)
211			np->name = "<NULL>";
212
213		phandle = __of_get_property(np, "phandle", &sz);
214		if (!phandle)
215			phandle = __of_get_property(np, "linux,phandle", &sz);
216		if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
217			phandle = __of_get_property(np, "ibm,phandle", &sz);
218		if (phandle && (sz >= 4))
219			np->phandle = be32_to_cpup(phandle);
220		else
221			np->phandle = 0;
222	}
223
224	np->child = NULL;
225	np->sibling = np->parent->child;
226	np->parent->child = np;
227	of_node_clear_flag(np, OF_DETACHED);
228}
229
230/**
231 * of_attach_node() - Plug a device node into the tree and global list.
232 */
233int of_attach_node(struct device_node *np)
234{
235	struct of_reconfig_data rd;
236	unsigned long flags;
237
238	memset(&rd, 0, sizeof(rd));
239	rd.dn = np;
240
241	mutex_lock(&of_mutex);
242	raw_spin_lock_irqsave(&devtree_lock, flags);
243	__of_attach_node(np);
244	raw_spin_unlock_irqrestore(&devtree_lock, flags);
245
246	__of_attach_node_sysfs(np);
247	mutex_unlock(&of_mutex);
248
249	of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);
250
251	return 0;
252}
253
254void __of_detach_node(struct device_node *np)
255{
256	struct device_node *parent;
257
258	if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
259		return;
260
261	parent = np->parent;
262	if (WARN_ON(!parent))
263		return;
264
265	if (parent->child == np)
266		parent->child = np->sibling;
267	else {
268		struct device_node *prevsib;
269		for (prevsib = np->parent->child;
270		     prevsib->sibling != np;
271		     prevsib = prevsib->sibling)
272			;
273		prevsib->sibling = np->sibling;
274	}
275
276	of_node_set_flag(np, OF_DETACHED);
277
278	/* race with of_find_node_by_phandle() prevented by devtree_lock */
279	__of_phandle_cache_inv_entry(np->phandle);
280}
281
282/**
283 * of_detach_node() - "Unplug" a node from the device tree.
284 */
285int of_detach_node(struct device_node *np)
286{
287	struct of_reconfig_data rd;
288	unsigned long flags;
 
289
290	memset(&rd, 0, sizeof(rd));
291	rd.dn = np;
292
293	mutex_lock(&of_mutex);
294	raw_spin_lock_irqsave(&devtree_lock, flags);
295	__of_detach_node(np);
296	raw_spin_unlock_irqrestore(&devtree_lock, flags);
297
298	__of_detach_node_sysfs(np);
299	mutex_unlock(&of_mutex);
300
301	of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
302
303	return 0;
304}
305EXPORT_SYMBOL_GPL(of_detach_node);
306
307static void property_list_free(struct property *prop_list)
308{
309	struct property *prop, *next;
310
311	for (prop = prop_list; prop != NULL; prop = next) {
312		next = prop->next;
313		kfree(prop->name);
314		kfree(prop->value);
315		kfree(prop);
316	}
317}
318
319/**
320 * of_node_release() - release a dynamically allocated node
321 * @kref: kref element of the node to be released
322 *
323 * In of_node_put() this function is passed to kref_put() as the destructor.
324 */
325void of_node_release(struct kobject *kobj)
326{
327	struct device_node *node = kobj_to_device_node(kobj);
328
329	/* We should never be releasing nodes that haven't been detached. */
330	if (!of_node_check_flag(node, OF_DETACHED)) {
331		pr_err("ERROR: Bad of_node_put() on %pOF\n", node);
332		dump_stack();
333		return;
334	}
335	if (!of_node_check_flag(node, OF_DYNAMIC))
336		return;
337
338	if (of_node_check_flag(node, OF_OVERLAY)) {
339
340		if (!of_node_check_flag(node, OF_OVERLAY_FREE_CSET)) {
341			/* premature refcount of zero, do not free memory */
342			pr_err("ERROR: memory leak before free overlay changeset,  %pOF\n",
343			       node);
344			return;
345		}
346
347		/*
348		 * If node->properties non-empty then properties were added
349		 * to this node either by different overlay that has not
350		 * yet been removed, or by a non-overlay mechanism.
351		 */
352		if (node->properties)
353			pr_err("ERROR: %s(), unexpected properties in %pOF\n",
354			       __func__, node);
355	}
356
357	property_list_free(node->properties);
358	property_list_free(node->deadprops);
359
360	kfree(node->full_name);
361	kfree(node->data);
362	kfree(node);
363}
364
365/**
366 * __of_prop_dup - Copy a property dynamically.
367 * @prop:	Property to copy
368 * @allocflags:	Allocation flags (typically pass GFP_KERNEL)
369 *
370 * Copy a property by dynamically allocating the memory of both the
371 * property structure and the property name & contents. The property's
372 * flags have the OF_DYNAMIC bit set so that we can differentiate between
373 * dynamically allocated properties and not.
374 * Returns the newly allocated property or NULL on out of memory error.
375 */
376struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
377{
378	struct property *new;
379
380	new = kzalloc(sizeof(*new), allocflags);
381	if (!new)
382		return NULL;
383
384	/*
385	 * NOTE: There is no check for zero length value.
386	 * In case of a boolean property, this will allocate a value
387	 * of zero bytes. We do this to work around the use
388	 * of of_get_property() calls on boolean values.
389	 */
390	new->name = kstrdup(prop->name, allocflags);
391	new->value = kmemdup(prop->value, prop->length, allocflags);
392	new->length = prop->length;
393	if (!new->name || !new->value)
394		goto err_free;
395
396	/* mark the property as dynamic */
397	of_property_set_flag(new, OF_DYNAMIC);
398
399	return new;
400
401 err_free:
402	kfree(new->name);
403	kfree(new->value);
404	kfree(new);
405	return NULL;
406}
407
408/**
409 * __of_node_dup() - Duplicate or create an empty device node dynamically.
410 * @np:		if not NULL, contains properties to be duplicated in new node
411 * @full_name:	string value to be duplicated into new node's full_name field
412 *
413 * Create a device tree node, optionally duplicating the properties of
414 * another node.  The node data are dynamically allocated and all the node
415 * flags have the OF_DYNAMIC & OF_DETACHED bits set.
416 *
417 * Returns the newly allocated node or NULL on out of memory error.
418 */
419struct device_node *__of_node_dup(const struct device_node *np,
420				  const char *full_name)
421{
422	struct device_node *node;
423
424	node = kzalloc(sizeof(*node), GFP_KERNEL);
425	if (!node)
426		return NULL;
427	node->full_name = kstrdup(full_name, GFP_KERNEL);
428	if (!node->full_name) {
429		kfree(node);
430		return NULL;
431	}
432
433	of_node_set_flag(node, OF_DYNAMIC);
434	of_node_set_flag(node, OF_DETACHED);
435	of_node_init(node);
436
437	/* Iterate over and duplicate all properties */
438	if (np) {
439		struct property *pp, *new_pp;
440		for_each_property_of_node(np, pp) {
441			new_pp = __of_prop_dup(pp, GFP_KERNEL);
442			if (!new_pp)
443				goto err_prop;
444			if (__of_add_property(node, new_pp)) {
445				kfree(new_pp->name);
446				kfree(new_pp->value);
447				kfree(new_pp);
448				goto err_prop;
449			}
450		}
451	}
452	return node;
453
454 err_prop:
455	of_node_put(node); /* Frees the node and properties */
456	return NULL;
457}
458
459static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
460{
461	if (ce->action == OF_RECONFIG_ATTACH_NODE &&
462	    of_node_check_flag(ce->np, OF_OVERLAY)) {
463		if (kref_read(&ce->np->kobj.kref) > 1) {
464			pr_err("ERROR: memory leak, expected refcount 1 instead of %d, of_node_get()/of_node_put() unbalanced - destroy cset entry: attach overlay node %pOF\n",
465			       kref_read(&ce->np->kobj.kref), ce->np);
466		} else {
467			of_node_set_flag(ce->np, OF_OVERLAY_FREE_CSET);
468		}
469	}
470
471	of_node_put(ce->np);
472	list_del(&ce->node);
473	kfree(ce);
474}
475
476#ifdef DEBUG
477static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
478{
479	switch (ce->action) {
480	case OF_RECONFIG_ADD_PROPERTY:
481	case OF_RECONFIG_REMOVE_PROPERTY:
482	case OF_RECONFIG_UPDATE_PROPERTY:
483		pr_debug("cset<%p> %-15s %pOF/%s\n", ce, action_names[ce->action],
484			ce->np, ce->prop->name);
485		break;
486	case OF_RECONFIG_ATTACH_NODE:
487	case OF_RECONFIG_DETACH_NODE:
488		pr_debug("cset<%p> %-15s %pOF\n", ce, action_names[ce->action],
489			ce->np);
490		break;
491	}
492}
493#else
494static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
495{
496	/* empty */
497}
498#endif
499
500static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
501					  struct of_changeset_entry *rce)
502{
503	memcpy(rce, ce, sizeof(*rce));
504
505	switch (ce->action) {
506	case OF_RECONFIG_ATTACH_NODE:
507		rce->action = OF_RECONFIG_DETACH_NODE;
508		break;
509	case OF_RECONFIG_DETACH_NODE:
510		rce->action = OF_RECONFIG_ATTACH_NODE;
511		break;
512	case OF_RECONFIG_ADD_PROPERTY:
513		rce->action = OF_RECONFIG_REMOVE_PROPERTY;
514		break;
515	case OF_RECONFIG_REMOVE_PROPERTY:
516		rce->action = OF_RECONFIG_ADD_PROPERTY;
517		break;
518	case OF_RECONFIG_UPDATE_PROPERTY:
519		rce->old_prop = ce->prop;
520		rce->prop = ce->old_prop;
521		/* update was used but original property did not exist */
522		if (!rce->prop) {
523			rce->action = OF_RECONFIG_REMOVE_PROPERTY;
524			rce->prop = ce->prop;
525		}
526		break;
527	}
528}
529
530static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
531		bool revert)
532{
533	struct of_reconfig_data rd;
534	struct of_changeset_entry ce_inverted;
535	int ret = 0;
536
537	if (revert) {
538		__of_changeset_entry_invert(ce, &ce_inverted);
539		ce = &ce_inverted;
540	}
541
542	switch (ce->action) {
543	case OF_RECONFIG_ATTACH_NODE:
544	case OF_RECONFIG_DETACH_NODE:
545		memset(&rd, 0, sizeof(rd));
546		rd.dn = ce->np;
547		ret = of_reconfig_notify(ce->action, &rd);
548		break;
549	case OF_RECONFIG_ADD_PROPERTY:
550	case OF_RECONFIG_REMOVE_PROPERTY:
551	case OF_RECONFIG_UPDATE_PROPERTY:
552		ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
553		break;
554	default:
555		pr_err("invalid devicetree changeset action: %i\n",
556			(int)ce->action);
557		ret = -EINVAL;
558	}
559
560	if (ret)
561		pr_err("changeset notifier error @%pOF\n", ce->np);
562	return ret;
563}
564
565static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
566{
567	struct property *old_prop, **propp;
568	unsigned long flags;
569	int ret = 0;
570
571	__of_changeset_entry_dump(ce);
572
573	raw_spin_lock_irqsave(&devtree_lock, flags);
574	switch (ce->action) {
575	case OF_RECONFIG_ATTACH_NODE:
576		__of_attach_node(ce->np);
577		break;
578	case OF_RECONFIG_DETACH_NODE:
579		__of_detach_node(ce->np);
580		break;
581	case OF_RECONFIG_ADD_PROPERTY:
582		/* If the property is in deadprops then it must be removed */
583		for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
584			if (*propp == ce->prop) {
585				*propp = ce->prop->next;
586				ce->prop->next = NULL;
587				break;
588			}
589		}
590
591		ret = __of_add_property(ce->np, ce->prop);
592		if (ret) {
593			pr_err("changeset: add_property failed @%pOF/%s\n",
594				ce->np,
595				ce->prop->name);
596			break;
597		}
598		break;
599	case OF_RECONFIG_REMOVE_PROPERTY:
600		ret = __of_remove_property(ce->np, ce->prop);
601		if (ret) {
602			pr_err("changeset: remove_property failed @%pOF/%s\n",
603				ce->np,
604				ce->prop->name);
605			break;
606		}
607		break;
608
609	case OF_RECONFIG_UPDATE_PROPERTY:
610		/* If the property is in deadprops then it must be removed */
611		for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
612			if (*propp == ce->prop) {
613				*propp = ce->prop->next;
614				ce->prop->next = NULL;
615				break;
616			}
617		}
618
619		ret = __of_update_property(ce->np, ce->prop, &old_prop);
620		if (ret) {
621			pr_err("changeset: update_property failed @%pOF/%s\n",
622				ce->np,
623				ce->prop->name);
624			break;
625		}
626		break;
627	default:
628		ret = -EINVAL;
629	}
630	raw_spin_unlock_irqrestore(&devtree_lock, flags);
631
632	if (ret)
633		return ret;
634
635	switch (ce->action) {
636	case OF_RECONFIG_ATTACH_NODE:
637		__of_attach_node_sysfs(ce->np);
638		break;
639	case OF_RECONFIG_DETACH_NODE:
640		__of_detach_node_sysfs(ce->np);
641		break;
642	case OF_RECONFIG_ADD_PROPERTY:
643		/* ignore duplicate names */
644		__of_add_property_sysfs(ce->np, ce->prop);
645		break;
646	case OF_RECONFIG_REMOVE_PROPERTY:
647		__of_remove_property_sysfs(ce->np, ce->prop);
648		break;
649	case OF_RECONFIG_UPDATE_PROPERTY:
650		__of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
651		break;
652	}
653
654	return 0;
655}
656
657static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
658{
659	struct of_changeset_entry ce_inverted;
660
661	__of_changeset_entry_invert(ce, &ce_inverted);
662	return __of_changeset_entry_apply(&ce_inverted);
663}
664
665/**
666 * of_changeset_init - Initialize a changeset for use
667 *
668 * @ocs:	changeset pointer
669 *
670 * Initialize a changeset structure
671 */
672void of_changeset_init(struct of_changeset *ocs)
673{
674	memset(ocs, 0, sizeof(*ocs));
675	INIT_LIST_HEAD(&ocs->entries);
676}
677EXPORT_SYMBOL_GPL(of_changeset_init);
678
679/**
680 * of_changeset_destroy - Destroy a changeset
681 *
682 * @ocs:	changeset pointer
683 *
684 * Destroys a changeset. Note that if a changeset is applied,
685 * its changes to the tree cannot be reverted.
686 */
687void of_changeset_destroy(struct of_changeset *ocs)
688{
689	struct of_changeset_entry *ce, *cen;
690
691	list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
692		__of_changeset_entry_destroy(ce);
693}
694EXPORT_SYMBOL_GPL(of_changeset_destroy);
695
696/*
697 * Apply the changeset entries in @ocs.
698 * If apply fails, an attempt is made to revert the entries that were
699 * successfully applied.
700 *
701 * If multiple revert errors occur then only the final revert error is reported.
702 *
703 * Returns 0 on success, a negative error value in case of an error.
704 * If a revert error occurs, it is returned in *ret_revert.
705 */
706int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
707{
708	struct of_changeset_entry *ce;
709	int ret, ret_tmp;
710
711	pr_debug("changeset: applying...\n");
712	list_for_each_entry(ce, &ocs->entries, node) {
713		ret = __of_changeset_entry_apply(ce);
714		if (ret) {
715			pr_err("Error applying changeset (%d)\n", ret);
716			list_for_each_entry_continue_reverse(ce, &ocs->entries,
717							     node) {
718				ret_tmp = __of_changeset_entry_revert(ce);
719				if (ret_tmp)
720					*ret_revert = ret_tmp;
721			}
722			return ret;
723		}
724	}
725
726	return 0;
727}
728
729/*
730 * Returns 0 on success, a negative error value in case of an error.
731 *
732 * If multiple changeset entry notification errors occur then only the
733 * final notification error is reported.
734 */
735int __of_changeset_apply_notify(struct of_changeset *ocs)
736{
737	struct of_changeset_entry *ce;
738	int ret = 0, ret_tmp;
739
740	pr_debug("changeset: emitting notifiers.\n");
741
742	/* drop the global lock while emitting notifiers */
743	mutex_unlock(&of_mutex);
744	list_for_each_entry(ce, &ocs->entries, node) {
745		ret_tmp = __of_changeset_entry_notify(ce, 0);
746		if (ret_tmp)
747			ret = ret_tmp;
748	}
749	mutex_lock(&of_mutex);
750	pr_debug("changeset: notifiers sent.\n");
751
752	return ret;
753}
754
755/*
756 * Returns 0 on success, a negative error value in case of an error.
757 *
758 * If a changeset entry apply fails, an attempt is made to revert any
759 * previous entries in the changeset.  If any of the reverts fails,
760 * that failure is not reported.  Thus the state of the device tree
761 * is unknown if an apply error occurs.
762 */
763static int __of_changeset_apply(struct of_changeset *ocs)
764{
765	int ret, ret_revert = 0;
766
767	ret = __of_changeset_apply_entries(ocs, &ret_revert);
768	if (!ret)
769		ret = __of_changeset_apply_notify(ocs);
770
771	return ret;
772}
773
774/**
775 * of_changeset_apply - Applies a changeset
776 *
777 * @ocs:	changeset pointer
778 *
779 * Applies a changeset to the live tree.
780 * Any side-effects of live tree state changes are applied here on
781 * success, like creation/destruction of devices and side-effects
782 * like creation of sysfs properties and directories.
783 * Returns 0 on success, a negative error value in case of an error.
784 * On error the partially applied effects are reverted.
785 */
786int of_changeset_apply(struct of_changeset *ocs)
787{
788	int ret;
789
790	mutex_lock(&of_mutex);
791	ret = __of_changeset_apply(ocs);
792	mutex_unlock(&of_mutex);
793
794	return ret;
795}
796EXPORT_SYMBOL_GPL(of_changeset_apply);
797
798/*
799 * Revert the changeset entries in @ocs.
800 * If revert fails, an attempt is made to re-apply the entries that were
801 * successfully removed.
802 *
803 * If multiple re-apply errors occur then only the final apply error is
804 * reported.
805 *
806 * Returns 0 on success, a negative error value in case of an error.
807 * If an apply error occurs, it is returned in *ret_apply.
808 */
809int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
810{
811	struct of_changeset_entry *ce;
812	int ret, ret_tmp;
813
814	pr_debug("changeset: reverting...\n");
815	list_for_each_entry_reverse(ce, &ocs->entries, node) {
816		ret = __of_changeset_entry_revert(ce);
817		if (ret) {
818			pr_err("Error reverting changeset (%d)\n", ret);
819			list_for_each_entry_continue(ce, &ocs->entries, node) {
820				ret_tmp = __of_changeset_entry_apply(ce);
821				if (ret_tmp)
822					*ret_apply = ret_tmp;
823			}
824			return ret;
825		}
826	}
827
828	return 0;
829}
830
831/*
832 * If multiple changeset entry notification errors occur then only the
833 * final notification error is reported.
834 */
835int __of_changeset_revert_notify(struct of_changeset *ocs)
836{
837	struct of_changeset_entry *ce;
838	int ret = 0, ret_tmp;
839
840	pr_debug("changeset: emitting notifiers.\n");
841
842	/* drop the global lock while emitting notifiers */
843	mutex_unlock(&of_mutex);
844	list_for_each_entry_reverse(ce, &ocs->entries, node) {
845		ret_tmp = __of_changeset_entry_notify(ce, 1);
846		if (ret_tmp)
847			ret = ret_tmp;
848	}
849	mutex_lock(&of_mutex);
850	pr_debug("changeset: notifiers sent.\n");
851
852	return ret;
853}
854
855static int __of_changeset_revert(struct of_changeset *ocs)
856{
857	int ret, ret_reply;
858
859	ret_reply = 0;
860	ret = __of_changeset_revert_entries(ocs, &ret_reply);
861
862	if (!ret)
863		ret = __of_changeset_revert_notify(ocs);
864
865	return ret;
866}
867
868/**
869 * of_changeset_revert - Reverts an applied changeset
870 *
871 * @ocs:	changeset pointer
872 *
873 * Reverts a changeset returning the state of the tree to what it
874 * was before the application.
875 * Any side-effects like creation/destruction of devices and
876 * removal of sysfs properties and directories are applied.
877 * Returns 0 on success, a negative error value in case of an error.
878 */
879int of_changeset_revert(struct of_changeset *ocs)
880{
881	int ret;
882
883	mutex_lock(&of_mutex);
884	ret = __of_changeset_revert(ocs);
885	mutex_unlock(&of_mutex);
886
887	return ret;
888}
889EXPORT_SYMBOL_GPL(of_changeset_revert);
890
891/**
892 * of_changeset_action - Add an action to the tail of the changeset list
893 *
894 * @ocs:	changeset pointer
895 * @action:	action to perform
896 * @np:		Pointer to device node
897 * @prop:	Pointer to property
898 *
899 * On action being one of:
900 * + OF_RECONFIG_ATTACH_NODE
901 * + OF_RECONFIG_DETACH_NODE,
902 * + OF_RECONFIG_ADD_PROPERTY
903 * + OF_RECONFIG_REMOVE_PROPERTY,
904 * + OF_RECONFIG_UPDATE_PROPERTY
905 * Returns 0 on success, a negative error value in case of an error.
906 */
907int of_changeset_action(struct of_changeset *ocs, unsigned long action,
908		struct device_node *np, struct property *prop)
909{
910	struct of_changeset_entry *ce;
911
912	ce = kzalloc(sizeof(*ce), GFP_KERNEL);
913	if (!ce)
914		return -ENOMEM;
915
916	/* get a reference to the node */
917	ce->action = action;
918	ce->np = of_node_get(np);
919	ce->prop = prop;
920
921	if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
922		ce->old_prop = of_find_property(np, prop->name, NULL);
923
924	/* add it to the list */
925	list_add_tail(&ce->node, &ocs->entries);
926	return 0;
927}
928EXPORT_SYMBOL_GPL(of_changeset_action);