1 // SPDX-License-Identifier: GPL-2.0
3 * Support for dynamic device trees.
5 * On some platforms, the device tree can be manipulated at runtime.
6 * The routines in this section support adding, removing and changing
10 #define pr_fmt(fmt) "OF: " fmt
12 #include <linux/device.h>
14 #include <linux/spinlock.h>
15 #include <linux/slab.h>
16 #include <linux/string.h>
17 #include <linux/proc_fs.h>
19 #include "of_private.h"
21 static struct device_node *kobj_to_device_node(struct kobject *kobj)
23 return container_of(kobj, struct device_node, kobj);
27 * of_node_get() - Increment refcount of a node
28 * @node: Node to inc refcount, NULL is supported to simplify writing of
31 * Return: The node with refcount incremented.
33 struct device_node *of_node_get(struct device_node *node)
36 kobject_get(&node->kobj);
39 EXPORT_SYMBOL(of_node_get);
42 * of_node_put() - Decrement refcount of a node
43 * @node: Node to dec refcount, NULL is supported to simplify writing of
46 void of_node_put(struct device_node *node)
49 kobject_put(&node->kobj);
51 EXPORT_SYMBOL(of_node_put);
53 static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
55 int of_reconfig_notifier_register(struct notifier_block *nb)
57 return blocking_notifier_chain_register(&of_reconfig_chain, nb);
59 EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
61 int of_reconfig_notifier_unregister(struct notifier_block *nb)
63 return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
65 EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
67 static const char *action_names[] = {
69 [OF_RECONFIG_ATTACH_NODE] = "ATTACH_NODE",
70 [OF_RECONFIG_DETACH_NODE] = "DETACH_NODE",
71 [OF_RECONFIG_ADD_PROPERTY] = "ADD_PROPERTY",
72 [OF_RECONFIG_REMOVE_PROPERTY] = "REMOVE_PROPERTY",
73 [OF_RECONFIG_UPDATE_PROPERTY] = "UPDATE_PROPERTY",
76 int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
80 struct of_reconfig_data *pr = p;
83 case OF_RECONFIG_ATTACH_NODE:
84 case OF_RECONFIG_DETACH_NODE:
85 pr_debug("notify %-15s %pOF\n", action_names[action],
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);
97 rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
98 return notifier_to_errno(rc);
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
106 * Returns the new state of a device based on the notifier used.
108 * Return: OF_RECONFIG_CHANGE_REMOVE on device going from enabled to
109 * disabled, OF_RECONFIG_CHANGE_ADD on device going from disabled to
110 * enabled and OF_RECONFIG_NO_CHANGE on no change.
112 int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr)
114 struct property *prop, *old_prop = NULL;
115 int is_status, status_state, old_status_state, prev_state, new_state;
117 /* figure out if a device should be created or destroyed */
119 case OF_RECONFIG_ATTACH_NODE:
120 case OF_RECONFIG_DETACH_NODE:
121 prop = of_find_property(pr->dn, "status", NULL);
123 case OF_RECONFIG_ADD_PROPERTY:
124 case OF_RECONFIG_REMOVE_PROPERTY:
127 case OF_RECONFIG_UPDATE_PROPERTY:
129 old_prop = pr->old_prop;
132 return OF_RECONFIG_NO_CHANGE;
137 old_status_state = -1;
141 if (prop && !strcmp(prop->name, "status")) {
143 status_state = !strcmp(prop->value, "okay") ||
144 !strcmp(prop->value, "ok");
146 old_status_state = !strcmp(old_prop->value, "okay") ||
147 !strcmp(old_prop->value, "ok");
151 case OF_RECONFIG_ATTACH_NODE:
153 /* -1 & 0 status either missing or okay */
154 new_state = status_state != 0;
156 case OF_RECONFIG_DETACH_NODE:
157 /* -1 & 0 status either missing or okay */
158 prev_state = status_state != 0;
161 case OF_RECONFIG_ADD_PROPERTY:
163 /* no status property -> enabled (legacy) */
165 new_state = status_state;
168 case OF_RECONFIG_REMOVE_PROPERTY:
170 prev_state = status_state;
171 /* no status property -> enabled (legacy) */
175 case OF_RECONFIG_UPDATE_PROPERTY:
177 prev_state = old_status_state != 0;
178 new_state = status_state != 0;
183 if (prev_state == new_state)
184 return OF_RECONFIG_NO_CHANGE;
186 return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
188 EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
190 int of_property_notify(int action, struct device_node *np,
191 struct property *prop, struct property *oldprop)
193 struct of_reconfig_data pr;
195 /* only call notifiers if the node is attached */
196 if (!of_node_is_attached(np))
201 pr.old_prop = oldprop;
202 return of_reconfig_notify(action, &pr);
205 static void __of_attach_node(struct device_node *np)
207 const __be32 *phandle;
210 if (!of_node_check_flag(np, OF_OVERLAY)) {
211 np->name = __of_get_property(np, "name", NULL);
215 phandle = __of_get_property(np, "phandle", &sz);
217 phandle = __of_get_property(np, "linux,phandle", &sz);
218 if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
219 phandle = __of_get_property(np, "ibm,phandle", &sz);
220 if (phandle && (sz >= 4))
221 np->phandle = be32_to_cpup(phandle);
227 np->sibling = np->parent->child;
228 np->parent->child = np;
229 of_node_clear_flag(np, OF_DETACHED);
233 * of_attach_node() - Plug a device node into the tree and global list.
235 int of_attach_node(struct device_node *np)
237 struct of_reconfig_data rd;
240 memset(&rd, 0, sizeof(rd));
243 mutex_lock(&of_mutex);
244 raw_spin_lock_irqsave(&devtree_lock, flags);
245 __of_attach_node(np);
246 raw_spin_unlock_irqrestore(&devtree_lock, flags);
248 __of_attach_node_sysfs(np);
249 mutex_unlock(&of_mutex);
251 of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);
256 void __of_detach_node(struct device_node *np)
258 struct device_node *parent;
260 if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
264 if (WARN_ON(!parent))
267 if (parent->child == np)
268 parent->child = np->sibling;
270 struct device_node *prevsib;
271 for (prevsib = np->parent->child;
272 prevsib->sibling != np;
273 prevsib = prevsib->sibling)
275 prevsib->sibling = np->sibling;
278 of_node_set_flag(np, OF_DETACHED);
280 /* race with of_find_node_by_phandle() prevented by devtree_lock */
281 __of_phandle_cache_inv_entry(np->phandle);
285 * of_detach_node() - "Unplug" a node from the device tree.
287 int of_detach_node(struct device_node *np)
289 struct of_reconfig_data rd;
292 memset(&rd, 0, sizeof(rd));
295 mutex_lock(&of_mutex);
296 raw_spin_lock_irqsave(&devtree_lock, flags);
297 __of_detach_node(np);
298 raw_spin_unlock_irqrestore(&devtree_lock, flags);
300 __of_detach_node_sysfs(np);
301 mutex_unlock(&of_mutex);
303 of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
307 EXPORT_SYMBOL_GPL(of_detach_node);
309 static void property_list_free(struct property *prop_list)
311 struct property *prop, *next;
313 for (prop = prop_list; prop != NULL; prop = next) {
322 * of_node_release() - release a dynamically allocated node
323 * @kref: kref element of the node to be released
325 * In of_node_put() this function is passed to kref_put() as the destructor.
327 void of_node_release(struct kobject *kobj)
329 struct device_node *node = kobj_to_device_node(kobj);
331 /* We should never be releasing nodes that haven't been detached. */
332 if (!of_node_check_flag(node, OF_DETACHED)) {
333 pr_err("ERROR: Bad of_node_put() on %pOF\n", node);
337 if (!of_node_check_flag(node, OF_DYNAMIC))
340 if (of_node_check_flag(node, OF_OVERLAY)) {
342 if (!of_node_check_flag(node, OF_OVERLAY_FREE_CSET)) {
343 /* premature refcount of zero, do not free memory */
344 pr_err("ERROR: memory leak before free overlay changeset, %pOF\n",
350 * If node->properties non-empty then properties were added
351 * to this node either by different overlay that has not
352 * yet been removed, or by a non-overlay mechanism.
354 if (node->properties)
355 pr_err("ERROR: %s(), unexpected properties in %pOF\n",
359 property_list_free(node->properties);
360 property_list_free(node->deadprops);
362 kfree(node->full_name);
368 * __of_prop_dup - Copy a property dynamically.
369 * @prop: Property to copy
370 * @allocflags: Allocation flags (typically pass GFP_KERNEL)
372 * Copy a property by dynamically allocating the memory of both the
373 * property structure and the property name & contents. The property's
374 * flags have the OF_DYNAMIC bit set so that we can differentiate between
375 * dynamically allocated properties and not.
377 * Return: The newly allocated property or NULL on out of memory error.
379 struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
381 struct property *new;
383 new = kzalloc(sizeof(*new), allocflags);
388 * NOTE: There is no check for zero length value.
389 * In case of a boolean property, this will allocate a value
390 * of zero bytes. We do this to work around the use
391 * of of_get_property() calls on boolean values.
393 new->name = kstrdup(prop->name, allocflags);
394 new->value = kmemdup(prop->value, prop->length, allocflags);
395 new->length = prop->length;
396 if (!new->name || !new->value)
399 /* mark the property as dynamic */
400 of_property_set_flag(new, OF_DYNAMIC);
412 * __of_node_dup() - Duplicate or create an empty device node dynamically.
413 * @np: if not NULL, contains properties to be duplicated in new node
414 * @full_name: string value to be duplicated into new node's full_name field
416 * Create a device tree node, optionally duplicating the properties of
417 * another node. The node data are dynamically allocated and all the node
418 * flags have the OF_DYNAMIC & OF_DETACHED bits set.
420 * Return: The newly allocated node or NULL on out of memory error.
422 struct device_node *__of_node_dup(const struct device_node *np,
423 const char *full_name)
425 struct device_node *node;
427 node = kzalloc(sizeof(*node), GFP_KERNEL);
430 node->full_name = kstrdup(full_name, GFP_KERNEL);
431 if (!node->full_name) {
436 of_node_set_flag(node, OF_DYNAMIC);
437 of_node_set_flag(node, OF_DETACHED);
440 /* Iterate over and duplicate all properties */
442 struct property *pp, *new_pp;
443 for_each_property_of_node(np, pp) {
444 new_pp = __of_prop_dup(pp, GFP_KERNEL);
447 if (__of_add_property(node, new_pp)) {
449 kfree(new_pp->value);
458 of_node_put(node); /* Frees the node and properties */
462 static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
464 if (ce->action == OF_RECONFIG_ATTACH_NODE &&
465 of_node_check_flag(ce->np, OF_OVERLAY)) {
466 if (kref_read(&ce->np->kobj.kref) > 1) {
467 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",
468 kref_read(&ce->np->kobj.kref), ce->np);
470 of_node_set_flag(ce->np, OF_OVERLAY_FREE_CSET);
480 static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
482 switch (ce->action) {
483 case OF_RECONFIG_ADD_PROPERTY:
484 case OF_RECONFIG_REMOVE_PROPERTY:
485 case OF_RECONFIG_UPDATE_PROPERTY:
486 pr_debug("cset<%p> %-15s %pOF/%s\n", ce, action_names[ce->action],
487 ce->np, ce->prop->name);
489 case OF_RECONFIG_ATTACH_NODE:
490 case OF_RECONFIG_DETACH_NODE:
491 pr_debug("cset<%p> %-15s %pOF\n", ce, action_names[ce->action],
497 static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
503 static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
504 struct of_changeset_entry *rce)
506 memcpy(rce, ce, sizeof(*rce));
508 switch (ce->action) {
509 case OF_RECONFIG_ATTACH_NODE:
510 rce->action = OF_RECONFIG_DETACH_NODE;
512 case OF_RECONFIG_DETACH_NODE:
513 rce->action = OF_RECONFIG_ATTACH_NODE;
515 case OF_RECONFIG_ADD_PROPERTY:
516 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
518 case OF_RECONFIG_REMOVE_PROPERTY:
519 rce->action = OF_RECONFIG_ADD_PROPERTY;
521 case OF_RECONFIG_UPDATE_PROPERTY:
522 rce->old_prop = ce->prop;
523 rce->prop = ce->old_prop;
524 /* update was used but original property did not exist */
526 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
527 rce->prop = ce->prop;
533 static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
536 struct of_reconfig_data rd;
537 struct of_changeset_entry ce_inverted;
541 __of_changeset_entry_invert(ce, &ce_inverted);
545 switch (ce->action) {
546 case OF_RECONFIG_ATTACH_NODE:
547 case OF_RECONFIG_DETACH_NODE:
548 memset(&rd, 0, sizeof(rd));
550 ret = of_reconfig_notify(ce->action, &rd);
552 case OF_RECONFIG_ADD_PROPERTY:
553 case OF_RECONFIG_REMOVE_PROPERTY:
554 case OF_RECONFIG_UPDATE_PROPERTY:
555 ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
558 pr_err("invalid devicetree changeset action: %i\n",
564 pr_err("changeset notifier error @%pOF\n", ce->np);
568 static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
570 struct property *old_prop, **propp;
574 __of_changeset_entry_dump(ce);
576 raw_spin_lock_irqsave(&devtree_lock, flags);
577 switch (ce->action) {
578 case OF_RECONFIG_ATTACH_NODE:
579 __of_attach_node(ce->np);
581 case OF_RECONFIG_DETACH_NODE:
582 __of_detach_node(ce->np);
584 case OF_RECONFIG_ADD_PROPERTY:
585 /* If the property is in deadprops then it must be removed */
586 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
587 if (*propp == ce->prop) {
588 *propp = ce->prop->next;
589 ce->prop->next = NULL;
594 ret = __of_add_property(ce->np, ce->prop);
596 case OF_RECONFIG_REMOVE_PROPERTY:
597 ret = __of_remove_property(ce->np, ce->prop);
600 case OF_RECONFIG_UPDATE_PROPERTY:
601 /* If the property is in deadprops then it must be removed */
602 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
603 if (*propp == ce->prop) {
604 *propp = ce->prop->next;
605 ce->prop->next = NULL;
610 ret = __of_update_property(ce->np, ce->prop, &old_prop);
615 raw_spin_unlock_irqrestore(&devtree_lock, flags);
618 pr_err("changeset: apply failed: %-15s %pOF:%s\n",
619 action_names[ce->action], ce->np, ce->prop->name);
623 switch (ce->action) {
624 case OF_RECONFIG_ATTACH_NODE:
625 __of_attach_node_sysfs(ce->np);
627 case OF_RECONFIG_DETACH_NODE:
628 __of_detach_node_sysfs(ce->np);
630 case OF_RECONFIG_ADD_PROPERTY:
631 /* ignore duplicate names */
632 __of_add_property_sysfs(ce->np, ce->prop);
634 case OF_RECONFIG_REMOVE_PROPERTY:
635 __of_remove_property_sysfs(ce->np, ce->prop);
637 case OF_RECONFIG_UPDATE_PROPERTY:
638 __of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
645 static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
647 struct of_changeset_entry ce_inverted;
649 __of_changeset_entry_invert(ce, &ce_inverted);
650 return __of_changeset_entry_apply(&ce_inverted);
654 * of_changeset_init - Initialize a changeset for use
656 * @ocs: changeset pointer
658 * Initialize a changeset structure
660 void of_changeset_init(struct of_changeset *ocs)
662 memset(ocs, 0, sizeof(*ocs));
663 INIT_LIST_HEAD(&ocs->entries);
665 EXPORT_SYMBOL_GPL(of_changeset_init);
668 * of_changeset_destroy - Destroy a changeset
670 * @ocs: changeset pointer
672 * Destroys a changeset. Note that if a changeset is applied,
673 * its changes to the tree cannot be reverted.
675 void of_changeset_destroy(struct of_changeset *ocs)
677 struct of_changeset_entry *ce, *cen;
680 * When a device is deleted, the device links to/from it are also queued
681 * for deletion. Until these device links are freed, the devices
682 * themselves aren't freed. If the device being deleted is due to an
683 * overlay change, this device might be holding a reference to a device
684 * node that will be freed. So, wait until all already pending device
685 * links are deleted before freeing a device node. This ensures we don't
686 * free any device node that has a non-zero reference count.
688 device_link_wait_removal();
690 list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
691 __of_changeset_entry_destroy(ce);
693 EXPORT_SYMBOL_GPL(of_changeset_destroy);
696 * Apply the changeset entries in @ocs.
697 * If apply fails, an attempt is made to revert the entries that were
698 * successfully applied.
700 * If multiple revert errors occur then only the final revert error is reported.
702 * Returns 0 on success, a negative error value in case of an error.
703 * If a revert error occurs, it is returned in *ret_revert.
705 int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
707 struct of_changeset_entry *ce;
710 pr_debug("changeset: applying...\n");
711 list_for_each_entry(ce, &ocs->entries, node) {
712 ret = __of_changeset_entry_apply(ce);
714 pr_err("Error applying changeset (%d)\n", ret);
715 list_for_each_entry_continue_reverse(ce, &ocs->entries,
717 ret_tmp = __of_changeset_entry_revert(ce);
719 *ret_revert = ret_tmp;
729 * Returns 0 on success, a negative error value in case of an error.
731 * If multiple changeset entry notification errors occur then only the
732 * final notification error is reported.
734 int __of_changeset_apply_notify(struct of_changeset *ocs)
736 struct of_changeset_entry *ce;
737 int ret = 0, ret_tmp;
739 pr_debug("changeset: emitting notifiers.\n");
741 /* drop the global lock while emitting notifiers */
742 mutex_unlock(&of_mutex);
743 list_for_each_entry(ce, &ocs->entries, node) {
744 ret_tmp = __of_changeset_entry_notify(ce, 0);
748 mutex_lock(&of_mutex);
749 pr_debug("changeset: notifiers sent.\n");
755 * Returns 0 on success, a negative error value in case of an error.
757 * If a changeset entry apply fails, an attempt is made to revert any
758 * previous entries in the changeset. If any of the reverts fails,
759 * that failure is not reported. Thus the state of the device tree
760 * is unknown if an apply error occurs.
762 static int __of_changeset_apply(struct of_changeset *ocs)
764 int ret, ret_revert = 0;
766 ret = __of_changeset_apply_entries(ocs, &ret_revert);
768 ret = __of_changeset_apply_notify(ocs);
774 * of_changeset_apply - Applies a changeset
776 * @ocs: changeset pointer
778 * Applies a changeset to the live tree.
779 * Any side-effects of live tree state changes are applied here on
780 * success, like creation/destruction of devices and side-effects
781 * like creation of sysfs properties and directories.
783 * Return: 0 on success, a negative error value in case of an error.
784 * On error the partially applied effects are reverted.
786 int of_changeset_apply(struct of_changeset *ocs)
790 mutex_lock(&of_mutex);
791 ret = __of_changeset_apply(ocs);
792 mutex_unlock(&of_mutex);
796 EXPORT_SYMBOL_GPL(of_changeset_apply);
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.
803 * If multiple re-apply errors occur then only the final apply error is
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.
809 int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
811 struct of_changeset_entry *ce;
814 pr_debug("changeset: reverting...\n");
815 list_for_each_entry_reverse(ce, &ocs->entries, node) {
816 ret = __of_changeset_entry_revert(ce);
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);
822 *ret_apply = ret_tmp;
832 * If multiple changeset entry notification errors occur then only the
833 * final notification error is reported.
835 int __of_changeset_revert_notify(struct of_changeset *ocs)
837 struct of_changeset_entry *ce;
838 int ret = 0, ret_tmp;
840 pr_debug("changeset: emitting notifiers.\n");
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);
849 mutex_lock(&of_mutex);
850 pr_debug("changeset: notifiers sent.\n");
855 static int __of_changeset_revert(struct of_changeset *ocs)
860 ret = __of_changeset_revert_entries(ocs, &ret_reply);
863 ret = __of_changeset_revert_notify(ocs);
869 * of_changeset_revert - Reverts an applied changeset
871 * @ocs: changeset pointer
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.
878 * Return: 0 on success, a negative error value in case of an error.
880 int of_changeset_revert(struct of_changeset *ocs)
884 mutex_lock(&of_mutex);
885 ret = __of_changeset_revert(ocs);
886 mutex_unlock(&of_mutex);
890 EXPORT_SYMBOL_GPL(of_changeset_revert);
893 * of_changeset_action - Add an action to the tail of the changeset list
895 * @ocs: changeset pointer
896 * @action: action to perform
897 * @np: Pointer to device node
898 * @prop: Pointer to property
900 * On action being one of:
901 * + OF_RECONFIG_ATTACH_NODE
902 * + OF_RECONFIG_DETACH_NODE,
903 * + OF_RECONFIG_ADD_PROPERTY
904 * + OF_RECONFIG_REMOVE_PROPERTY,
905 * + OF_RECONFIG_UPDATE_PROPERTY
907 * Return: 0 on success, a negative error value in case of an error.
909 int of_changeset_action(struct of_changeset *ocs, unsigned long action,
910 struct device_node *np, struct property *prop)
912 struct of_changeset_entry *ce;
914 if (WARN_ON(action >= ARRAY_SIZE(action_names)))
917 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
921 /* get a reference to the node */
923 ce->np = of_node_get(np);
926 if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
927 ce->old_prop = of_find_property(np, prop->name, NULL);
929 /* add it to the list */
930 list_add_tail(&ce->node, &ocs->entries);
933 EXPORT_SYMBOL_GPL(of_changeset_action);