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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 np->name = __of_get_property(np, "name", NULL) ? : "<NULL>";
209 np->type = __of_get_property(np, "device_type", NULL) ? : "<NULL>";
210
211 phandle = __of_get_property(np, "phandle", &sz);
212 if (!phandle)
213 phandle = __of_get_property(np, "linux,phandle", &sz);
214 if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
215 phandle = __of_get_property(np, "ibm,phandle", &sz);
216 np->phandle = (phandle && (sz >= 4)) ? be32_to_cpup(phandle) : 0;
217
218 np->child = NULL;
219 np->sibling = np->parent->child;
220 np->parent->child = np;
221 of_node_clear_flag(np, OF_DETACHED);
222}
223
224/**
225 * of_attach_node() - Plug a device node into the tree and global list.
226 */
227int of_attach_node(struct device_node *np)
228{
229 struct of_reconfig_data rd;
230 unsigned long flags;
231
232 memset(&rd, 0, sizeof(rd));
233 rd.dn = np;
234
235 mutex_lock(&of_mutex);
236 raw_spin_lock_irqsave(&devtree_lock, flags);
237 __of_attach_node(np);
238 raw_spin_unlock_irqrestore(&devtree_lock, flags);
239
240 __of_attach_node_sysfs(np);
241 mutex_unlock(&of_mutex);
242
243 of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);
244
245 return 0;
246}
247
248void __of_detach_node(struct device_node *np)
249{
250 struct device_node *parent;
251
252 if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
253 return;
254
255 parent = np->parent;
256 if (WARN_ON(!parent))
257 return;
258
259 if (parent->child == np)
260 parent->child = np->sibling;
261 else {
262 struct device_node *prevsib;
263 for (prevsib = np->parent->child;
264 prevsib->sibling != np;
265 prevsib = prevsib->sibling)
266 ;
267 prevsib->sibling = np->sibling;
268 }
269
270 of_node_set_flag(np, OF_DETACHED);
271}
272
273/**
274 * of_detach_node() - "Unplug" a node from the device tree.
275 *
276 * The caller must hold a reference to the node. The memory associated with
277 * the node is not freed until its refcount goes to zero.
278 */
279int of_detach_node(struct device_node *np)
280{
281 struct of_reconfig_data rd;
282 unsigned long flags;
283 int rc = 0;
284
285 memset(&rd, 0, sizeof(rd));
286 rd.dn = np;
287
288 mutex_lock(&of_mutex);
289 raw_spin_lock_irqsave(&devtree_lock, flags);
290 __of_detach_node(np);
291 raw_spin_unlock_irqrestore(&devtree_lock, flags);
292
293 __of_detach_node_sysfs(np);
294 mutex_unlock(&of_mutex);
295
296 of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
297
298 return rc;
299}
300EXPORT_SYMBOL_GPL(of_detach_node);
301
302static void property_list_free(struct property *prop_list)
303{
304 struct property *prop, *next;
305
306 for (prop = prop_list; prop != NULL; prop = next) {
307 next = prop->next;
308 kfree(prop->name);
309 kfree(prop->value);
310 kfree(prop);
311 }
312}
313
314/**
315 * of_node_release() - release a dynamically allocated node
316 * @kref: kref element of the node to be released
317 *
318 * In of_node_put() this function is passed to kref_put() as the destructor.
319 */
320void of_node_release(struct kobject *kobj)
321{
322 struct device_node *node = kobj_to_device_node(kobj);
323
324 /* We should never be releasing nodes that haven't been detached. */
325 if (!of_node_check_flag(node, OF_DETACHED)) {
326 pr_err("ERROR: Bad of_node_put() on %pOF\n", node);
327 dump_stack();
328 return;
329 }
330 if (!of_node_check_flag(node, OF_DYNAMIC))
331 return;
332
333 property_list_free(node->properties);
334 property_list_free(node->deadprops);
335
336 kfree(node->full_name);
337 kfree(node->data);
338 kfree(node);
339}
340
341/**
342 * __of_prop_dup - Copy a property dynamically.
343 * @prop: Property to copy
344 * @allocflags: Allocation flags (typically pass GFP_KERNEL)
345 *
346 * Copy a property by dynamically allocating the memory of both the
347 * property structure and the property name & contents. The property's
348 * flags have the OF_DYNAMIC bit set so that we can differentiate between
349 * dynamically allocated properties and not.
350 * Returns the newly allocated property or NULL on out of memory error.
351 */
352struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
353{
354 struct property *new;
355
356 new = kzalloc(sizeof(*new), allocflags);
357 if (!new)
358 return NULL;
359
360 /*
361 * NOTE: There is no check for zero length value.
362 * In case of a boolean property, this will allocate a value
363 * of zero bytes. We do this to work around the use
364 * of of_get_property() calls on boolean values.
365 */
366 new->name = kstrdup(prop->name, allocflags);
367 new->value = kmemdup(prop->value, prop->length, allocflags);
368 new->length = prop->length;
369 if (!new->name || !new->value)
370 goto err_free;
371
372 /* mark the property as dynamic */
373 of_property_set_flag(new, OF_DYNAMIC);
374
375 return new;
376
377 err_free:
378 kfree(new->name);
379 kfree(new->value);
380 kfree(new);
381 return NULL;
382}
383
384/**
385 * __of_node_dup() - Duplicate or create an empty device node dynamically.
386 * @np: if not NULL, contains properties to be duplicated in new node
387 * @full_name: string value to be duplicated into new node's full_name field
388 *
389 * Create a device tree node, optionally duplicating the properties of
390 * another node. The node data are dynamically allocated and all the node
391 * flags have the OF_DYNAMIC & OF_DETACHED bits set.
392 *
393 * Returns the newly allocated node or NULL on out of memory error.
394 */
395struct device_node *__of_node_dup(const struct device_node *np,
396 const char *full_name)
397{
398 struct device_node *node;
399
400 node = kzalloc(sizeof(*node), GFP_KERNEL);
401 if (!node)
402 return NULL;
403 node->full_name = kstrdup(full_name, GFP_KERNEL);
404 if (!node->full_name) {
405 kfree(node);
406 return NULL;
407 }
408
409 of_node_set_flag(node, OF_DYNAMIC);
410 of_node_set_flag(node, OF_DETACHED);
411 of_node_init(node);
412
413 /* Iterate over and duplicate all properties */
414 if (np) {
415 struct property *pp, *new_pp;
416 for_each_property_of_node(np, pp) {
417 new_pp = __of_prop_dup(pp, GFP_KERNEL);
418 if (!new_pp)
419 goto err_prop;
420 if (__of_add_property(node, new_pp)) {
421 kfree(new_pp->name);
422 kfree(new_pp->value);
423 kfree(new_pp);
424 goto err_prop;
425 }
426 }
427 }
428 return node;
429
430 err_prop:
431 of_node_put(node); /* Frees the node and properties */
432 return NULL;
433}
434
435static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
436{
437 of_node_put(ce->np);
438 list_del(&ce->node);
439 kfree(ce);
440}
441
442#ifdef DEBUG
443static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
444{
445 switch (ce->action) {
446 case OF_RECONFIG_ADD_PROPERTY:
447 case OF_RECONFIG_REMOVE_PROPERTY:
448 case OF_RECONFIG_UPDATE_PROPERTY:
449 pr_debug("cset<%p> %-15s %pOF/%s\n", ce, action_names[ce->action],
450 ce->np, ce->prop->name);
451 break;
452 case OF_RECONFIG_ATTACH_NODE:
453 case OF_RECONFIG_DETACH_NODE:
454 pr_debug("cset<%p> %-15s %pOF\n", ce, action_names[ce->action],
455 ce->np);
456 break;
457 }
458}
459#else
460static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
461{
462 /* empty */
463}
464#endif
465
466static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
467 struct of_changeset_entry *rce)
468{
469 memcpy(rce, ce, sizeof(*rce));
470
471 switch (ce->action) {
472 case OF_RECONFIG_ATTACH_NODE:
473 rce->action = OF_RECONFIG_DETACH_NODE;
474 break;
475 case OF_RECONFIG_DETACH_NODE:
476 rce->action = OF_RECONFIG_ATTACH_NODE;
477 break;
478 case OF_RECONFIG_ADD_PROPERTY:
479 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
480 break;
481 case OF_RECONFIG_REMOVE_PROPERTY:
482 rce->action = OF_RECONFIG_ADD_PROPERTY;
483 break;
484 case OF_RECONFIG_UPDATE_PROPERTY:
485 rce->old_prop = ce->prop;
486 rce->prop = ce->old_prop;
487 /* update was used but original property did not exist */
488 if (!rce->prop) {
489 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
490 rce->prop = ce->prop;
491 }
492 break;
493 }
494}
495
496static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
497 bool revert)
498{
499 struct of_reconfig_data rd;
500 struct of_changeset_entry ce_inverted;
501 int ret = 0;
502
503 if (revert) {
504 __of_changeset_entry_invert(ce, &ce_inverted);
505 ce = &ce_inverted;
506 }
507
508 switch (ce->action) {
509 case OF_RECONFIG_ATTACH_NODE:
510 case OF_RECONFIG_DETACH_NODE:
511 memset(&rd, 0, sizeof(rd));
512 rd.dn = ce->np;
513 ret = of_reconfig_notify(ce->action, &rd);
514 break;
515 case OF_RECONFIG_ADD_PROPERTY:
516 case OF_RECONFIG_REMOVE_PROPERTY:
517 case OF_RECONFIG_UPDATE_PROPERTY:
518 ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
519 break;
520 default:
521 pr_err("invalid devicetree changeset action: %i\n",
522 (int)ce->action);
523 ret = -EINVAL;
524 }
525
526 if (ret)
527 pr_err("changeset notifier error @%pOF\n", ce->np);
528 return ret;
529}
530
531static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
532{
533 struct property *old_prop, **propp;
534 unsigned long flags;
535 int ret = 0;
536
537 __of_changeset_entry_dump(ce);
538
539 raw_spin_lock_irqsave(&devtree_lock, flags);
540 switch (ce->action) {
541 case OF_RECONFIG_ATTACH_NODE:
542 __of_attach_node(ce->np);
543 break;
544 case OF_RECONFIG_DETACH_NODE:
545 __of_detach_node(ce->np);
546 break;
547 case OF_RECONFIG_ADD_PROPERTY:
548 /* If the property is in deadprops then it must be removed */
549 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
550 if (*propp == ce->prop) {
551 *propp = ce->prop->next;
552 ce->prop->next = NULL;
553 break;
554 }
555 }
556
557 ret = __of_add_property(ce->np, ce->prop);
558 if (ret) {
559 pr_err("changeset: add_property failed @%pOF/%s\n",
560 ce->np,
561 ce->prop->name);
562 break;
563 }
564 break;
565 case OF_RECONFIG_REMOVE_PROPERTY:
566 ret = __of_remove_property(ce->np, ce->prop);
567 if (ret) {
568 pr_err("changeset: remove_property failed @%pOF/%s\n",
569 ce->np,
570 ce->prop->name);
571 break;
572 }
573 break;
574
575 case OF_RECONFIG_UPDATE_PROPERTY:
576 /* If the property is in deadprops then it must be removed */
577 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
578 if (*propp == ce->prop) {
579 *propp = ce->prop->next;
580 ce->prop->next = NULL;
581 break;
582 }
583 }
584
585 ret = __of_update_property(ce->np, ce->prop, &old_prop);
586 if (ret) {
587 pr_err("changeset: update_property failed @%pOF/%s\n",
588 ce->np,
589 ce->prop->name);
590 break;
591 }
592 break;
593 default:
594 ret = -EINVAL;
595 }
596 raw_spin_unlock_irqrestore(&devtree_lock, flags);
597
598 if (ret)
599 return ret;
600
601 switch (ce->action) {
602 case OF_RECONFIG_ATTACH_NODE:
603 __of_attach_node_sysfs(ce->np);
604 break;
605 case OF_RECONFIG_DETACH_NODE:
606 __of_detach_node_sysfs(ce->np);
607 break;
608 case OF_RECONFIG_ADD_PROPERTY:
609 /* ignore duplicate names */
610 __of_add_property_sysfs(ce->np, ce->prop);
611 break;
612 case OF_RECONFIG_REMOVE_PROPERTY:
613 __of_remove_property_sysfs(ce->np, ce->prop);
614 break;
615 case OF_RECONFIG_UPDATE_PROPERTY:
616 __of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
617 break;
618 }
619
620 return 0;
621}
622
623static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
624{
625 struct of_changeset_entry ce_inverted;
626
627 __of_changeset_entry_invert(ce, &ce_inverted);
628 return __of_changeset_entry_apply(&ce_inverted);
629}
630
631/**
632 * of_changeset_init - Initialize a changeset for use
633 *
634 * @ocs: changeset pointer
635 *
636 * Initialize a changeset structure
637 */
638void of_changeset_init(struct of_changeset *ocs)
639{
640 memset(ocs, 0, sizeof(*ocs));
641 INIT_LIST_HEAD(&ocs->entries);
642}
643EXPORT_SYMBOL_GPL(of_changeset_init);
644
645/**
646 * of_changeset_destroy - Destroy a changeset
647 *
648 * @ocs: changeset pointer
649 *
650 * Destroys a changeset. Note that if a changeset is applied,
651 * its changes to the tree cannot be reverted.
652 */
653void of_changeset_destroy(struct of_changeset *ocs)
654{
655 struct of_changeset_entry *ce, *cen;
656
657 list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
658 __of_changeset_entry_destroy(ce);
659}
660EXPORT_SYMBOL_GPL(of_changeset_destroy);
661
662/*
663 * Apply the changeset entries in @ocs.
664 * If apply fails, an attempt is made to revert the entries that were
665 * successfully applied.
666 *
667 * If multiple revert errors occur then only the final revert error is reported.
668 *
669 * Returns 0 on success, a negative error value in case of an error.
670 * If a revert error occurs, it is returned in *ret_revert.
671 */
672int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
673{
674 struct of_changeset_entry *ce;
675 int ret, ret_tmp;
676
677 pr_debug("changeset: applying...\n");
678 list_for_each_entry(ce, &ocs->entries, node) {
679 ret = __of_changeset_entry_apply(ce);
680 if (ret) {
681 pr_err("Error applying changeset (%d)\n", ret);
682 list_for_each_entry_continue_reverse(ce, &ocs->entries,
683 node) {
684 ret_tmp = __of_changeset_entry_revert(ce);
685 if (ret_tmp)
686 *ret_revert = ret_tmp;
687 }
688 return ret;
689 }
690 }
691
692 return 0;
693}
694
695/*
696 * Returns 0 on success, a negative error value in case of an error.
697 *
698 * If multiple changeset entry notification errors occur then only the
699 * final notification error is reported.
700 */
701int __of_changeset_apply_notify(struct of_changeset *ocs)
702{
703 struct of_changeset_entry *ce;
704 int ret = 0, ret_tmp;
705
706 pr_debug("changeset: emitting notifiers.\n");
707
708 /* drop the global lock while emitting notifiers */
709 mutex_unlock(&of_mutex);
710 list_for_each_entry(ce, &ocs->entries, node) {
711 ret_tmp = __of_changeset_entry_notify(ce, 0);
712 if (ret_tmp)
713 ret = ret_tmp;
714 }
715 mutex_lock(&of_mutex);
716 pr_debug("changeset: notifiers sent.\n");
717
718 return ret;
719}
720
721/*
722 * Returns 0 on success, a negative error value in case of an error.
723 *
724 * If a changeset entry apply fails, an attempt is made to revert any
725 * previous entries in the changeset. If any of the reverts fails,
726 * that failure is not reported. Thus the state of the device tree
727 * is unknown if an apply error occurs.
728 */
729static int __of_changeset_apply(struct of_changeset *ocs)
730{
731 int ret, ret_revert = 0;
732
733 ret = __of_changeset_apply_entries(ocs, &ret_revert);
734 if (!ret)
735 ret = __of_changeset_apply_notify(ocs);
736
737 return ret;
738}
739
740/**
741 * of_changeset_apply - Applies a changeset
742 *
743 * @ocs: changeset pointer
744 *
745 * Applies a changeset to the live tree.
746 * Any side-effects of live tree state changes are applied here on
747 * success, like creation/destruction of devices and side-effects
748 * like creation of sysfs properties and directories.
749 * Returns 0 on success, a negative error value in case of an error.
750 * On error the partially applied effects are reverted.
751 */
752int of_changeset_apply(struct of_changeset *ocs)
753{
754 int ret;
755
756 mutex_lock(&of_mutex);
757 ret = __of_changeset_apply(ocs);
758 mutex_unlock(&of_mutex);
759
760 return ret;
761}
762EXPORT_SYMBOL_GPL(of_changeset_apply);
763
764/*
765 * Revert the changeset entries in @ocs.
766 * If revert fails, an attempt is made to re-apply the entries that were
767 * successfully removed.
768 *
769 * If multiple re-apply errors occur then only the final apply error is
770 * reported.
771 *
772 * Returns 0 on success, a negative error value in case of an error.
773 * If an apply error occurs, it is returned in *ret_apply.
774 */
775int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
776{
777 struct of_changeset_entry *ce;
778 int ret, ret_tmp;
779
780 pr_debug("changeset: reverting...\n");
781 list_for_each_entry_reverse(ce, &ocs->entries, node) {
782 ret = __of_changeset_entry_revert(ce);
783 if (ret) {
784 pr_err("Error reverting changeset (%d)\n", ret);
785 list_for_each_entry_continue(ce, &ocs->entries, node) {
786 ret_tmp = __of_changeset_entry_apply(ce);
787 if (ret_tmp)
788 *ret_apply = ret_tmp;
789 }
790 return ret;
791 }
792 }
793
794 return 0;
795}
796
797/*
798 * If multiple changeset entry notification errors occur then only the
799 * final notification error is reported.
800 */
801int __of_changeset_revert_notify(struct of_changeset *ocs)
802{
803 struct of_changeset_entry *ce;
804 int ret = 0, ret_tmp;
805
806 pr_debug("changeset: emitting notifiers.\n");
807
808 /* drop the global lock while emitting notifiers */
809 mutex_unlock(&of_mutex);
810 list_for_each_entry_reverse(ce, &ocs->entries, node) {
811 ret_tmp = __of_changeset_entry_notify(ce, 1);
812 if (ret_tmp)
813 ret = ret_tmp;
814 }
815 mutex_lock(&of_mutex);
816 pr_debug("changeset: notifiers sent.\n");
817
818 return ret;
819}
820
821static int __of_changeset_revert(struct of_changeset *ocs)
822{
823 int ret, ret_reply;
824
825 ret_reply = 0;
826 ret = __of_changeset_revert_entries(ocs, &ret_reply);
827
828 if (!ret)
829 ret = __of_changeset_revert_notify(ocs);
830
831 return ret;
832}
833
834/**
835 * of_changeset_revert - Reverts an applied changeset
836 *
837 * @ocs: changeset pointer
838 *
839 * Reverts a changeset returning the state of the tree to what it
840 * was before the application.
841 * Any side-effects like creation/destruction of devices and
842 * removal of sysfs properties and directories are applied.
843 * Returns 0 on success, a negative error value in case of an error.
844 */
845int of_changeset_revert(struct of_changeset *ocs)
846{
847 int ret;
848
849 mutex_lock(&of_mutex);
850 ret = __of_changeset_revert(ocs);
851 mutex_unlock(&of_mutex);
852
853 return ret;
854}
855EXPORT_SYMBOL_GPL(of_changeset_revert);
856
857/**
858 * of_changeset_action - Add an action to the tail of the changeset list
859 *
860 * @ocs: changeset pointer
861 * @action: action to perform
862 * @np: Pointer to device node
863 * @prop: Pointer to property
864 *
865 * On action being one of:
866 * + OF_RECONFIG_ATTACH_NODE
867 * + OF_RECONFIG_DETACH_NODE,
868 * + OF_RECONFIG_ADD_PROPERTY
869 * + OF_RECONFIG_REMOVE_PROPERTY,
870 * + OF_RECONFIG_UPDATE_PROPERTY
871 * Returns 0 on success, a negative error value in case of an error.
872 */
873int of_changeset_action(struct of_changeset *ocs, unsigned long action,
874 struct device_node *np, struct property *prop)
875{
876 struct of_changeset_entry *ce;
877
878 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
879 if (!ce)
880 return -ENOMEM;
881
882 /* get a reference to the node */
883 ce->action = action;
884 ce->np = of_node_get(np);
885 ce->prop = prop;
886
887 if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
888 ce->old_prop = of_find_property(np, prop->name, NULL);
889
890 /* add it to the list */
891 list_add_tail(&ce->node, &ocs->entries);
892 return 0;
893}
894EXPORT_SYMBOL_GPL(of_changeset_action);