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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 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_free_phandle_cache_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 int rc = 0;
290
291 memset(&rd, 0, sizeof(rd));
292 rd.dn = np;
293
294 mutex_lock(&of_mutex);
295 raw_spin_lock_irqsave(&devtree_lock, flags);
296 __of_detach_node(np);
297 raw_spin_unlock_irqrestore(&devtree_lock, flags);
298
299 __of_detach_node_sysfs(np);
300 mutex_unlock(&of_mutex);
301
302 of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
303
304 return rc;
305}
306EXPORT_SYMBOL_GPL(of_detach_node);
307
308static void property_list_free(struct property *prop_list)
309{
310 struct property *prop, *next;
311
312 for (prop = prop_list; prop != NULL; prop = next) {
313 next = prop->next;
314 kfree(prop->name);
315 kfree(prop->value);
316 kfree(prop);
317 }
318}
319
320/**
321 * of_node_release() - release a dynamically allocated node
322 * @kref: kref element of the node to be released
323 *
324 * In of_node_put() this function is passed to kref_put() as the destructor.
325 */
326void of_node_release(struct kobject *kobj)
327{
328 struct device_node *node = kobj_to_device_node(kobj);
329
330 /* We should never be releasing nodes that haven't been detached. */
331 if (!of_node_check_flag(node, OF_DETACHED)) {
332 pr_err("ERROR: Bad of_node_put() on %pOF\n", node);
333 dump_stack();
334 return;
335 }
336 if (!of_node_check_flag(node, OF_DYNAMIC))
337 return;
338
339 if (of_node_check_flag(node, OF_OVERLAY)) {
340
341 if (!of_node_check_flag(node, OF_OVERLAY_FREE_CSET)) {
342 /* premature refcount of zero, do not free memory */
343 pr_err("ERROR: memory leak before free overlay changeset, %pOF\n",
344 node);
345 return;
346 }
347
348 /*
349 * If node->properties non-empty then properties were added
350 * to this node either by different overlay that has not
351 * yet been removed, or by a non-overlay mechanism.
352 */
353 if (node->properties)
354 pr_err("ERROR: %s(), unexpected properties in %pOF\n",
355 __func__, node);
356 }
357
358 property_list_free(node->properties);
359 property_list_free(node->deadprops);
360
361 kfree(node->full_name);
362 kfree(node->data);
363 kfree(node);
364}
365
366/**
367 * __of_prop_dup - Copy a property dynamically.
368 * @prop: Property to copy
369 * @allocflags: Allocation flags (typically pass GFP_KERNEL)
370 *
371 * Copy a property by dynamically allocating the memory of both the
372 * property structure and the property name & contents. The property's
373 * flags have the OF_DYNAMIC bit set so that we can differentiate between
374 * dynamically allocated properties and not.
375 * Returns the newly allocated property or NULL on out of memory error.
376 */
377struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
378{
379 struct property *new;
380
381 new = kzalloc(sizeof(*new), allocflags);
382 if (!new)
383 return NULL;
384
385 /*
386 * NOTE: There is no check for zero length value.
387 * In case of a boolean property, this will allocate a value
388 * of zero bytes. We do this to work around the use
389 * of of_get_property() calls on boolean values.
390 */
391 new->name = kstrdup(prop->name, allocflags);
392 new->value = kmemdup(prop->value, prop->length, allocflags);
393 new->length = prop->length;
394 if (!new->name || !new->value)
395 goto err_free;
396
397 /* mark the property as dynamic */
398 of_property_set_flag(new, OF_DYNAMIC);
399
400 return new;
401
402 err_free:
403 kfree(new->name);
404 kfree(new->value);
405 kfree(new);
406 return NULL;
407}
408
409/**
410 * __of_node_dup() - Duplicate or create an empty device node dynamically.
411 * @np: if not NULL, contains properties to be duplicated in new node
412 * @full_name: string value to be duplicated into new node's full_name field
413 *
414 * Create a device tree node, optionally duplicating the properties of
415 * another node. The node data are dynamically allocated and all the node
416 * flags have the OF_DYNAMIC & OF_DETACHED bits set.
417 *
418 * Returns the newly allocated node or NULL on out of memory error.
419 */
420struct device_node *__of_node_dup(const struct device_node *np,
421 const char *full_name)
422{
423 struct device_node *node;
424
425 node = kzalloc(sizeof(*node), GFP_KERNEL);
426 if (!node)
427 return NULL;
428 node->full_name = kstrdup(full_name, GFP_KERNEL);
429 if (!node->full_name) {
430 kfree(node);
431 return NULL;
432 }
433
434 of_node_set_flag(node, OF_DYNAMIC);
435 of_node_set_flag(node, OF_DETACHED);
436 of_node_init(node);
437
438 /* Iterate over and duplicate all properties */
439 if (np) {
440 struct property *pp, *new_pp;
441 for_each_property_of_node(np, pp) {
442 new_pp = __of_prop_dup(pp, GFP_KERNEL);
443 if (!new_pp)
444 goto err_prop;
445 if (__of_add_property(node, new_pp)) {
446 kfree(new_pp->name);
447 kfree(new_pp->value);
448 kfree(new_pp);
449 goto err_prop;
450 }
451 }
452 }
453 return node;
454
455 err_prop:
456 of_node_put(node); /* Frees the node and properties */
457 return NULL;
458}
459
460static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
461{
462 if (ce->action == OF_RECONFIG_ATTACH_NODE &&
463 of_node_check_flag(ce->np, OF_OVERLAY)) {
464 if (kref_read(&ce->np->kobj.kref) > 1) {
465 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",
466 kref_read(&ce->np->kobj.kref), ce->np);
467 } else {
468 of_node_set_flag(ce->np, OF_OVERLAY_FREE_CSET);
469 }
470 }
471
472 of_node_put(ce->np);
473 list_del(&ce->node);
474 kfree(ce);
475}
476
477#ifdef DEBUG
478static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
479{
480 switch (ce->action) {
481 case OF_RECONFIG_ADD_PROPERTY:
482 case OF_RECONFIG_REMOVE_PROPERTY:
483 case OF_RECONFIG_UPDATE_PROPERTY:
484 pr_debug("cset<%p> %-15s %pOF/%s\n", ce, action_names[ce->action],
485 ce->np, ce->prop->name);
486 break;
487 case OF_RECONFIG_ATTACH_NODE:
488 case OF_RECONFIG_DETACH_NODE:
489 pr_debug("cset<%p> %-15s %pOF\n", ce, action_names[ce->action],
490 ce->np);
491 break;
492 }
493}
494#else
495static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
496{
497 /* empty */
498}
499#endif
500
501static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
502 struct of_changeset_entry *rce)
503{
504 memcpy(rce, ce, sizeof(*rce));
505
506 switch (ce->action) {
507 case OF_RECONFIG_ATTACH_NODE:
508 rce->action = OF_RECONFIG_DETACH_NODE;
509 break;
510 case OF_RECONFIG_DETACH_NODE:
511 rce->action = OF_RECONFIG_ATTACH_NODE;
512 break;
513 case OF_RECONFIG_ADD_PROPERTY:
514 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
515 break;
516 case OF_RECONFIG_REMOVE_PROPERTY:
517 rce->action = OF_RECONFIG_ADD_PROPERTY;
518 break;
519 case OF_RECONFIG_UPDATE_PROPERTY:
520 rce->old_prop = ce->prop;
521 rce->prop = ce->old_prop;
522 /* update was used but original property did not exist */
523 if (!rce->prop) {
524 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
525 rce->prop = ce->prop;
526 }
527 break;
528 }
529}
530
531static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
532 bool revert)
533{
534 struct of_reconfig_data rd;
535 struct of_changeset_entry ce_inverted;
536 int ret = 0;
537
538 if (revert) {
539 __of_changeset_entry_invert(ce, &ce_inverted);
540 ce = &ce_inverted;
541 }
542
543 switch (ce->action) {
544 case OF_RECONFIG_ATTACH_NODE:
545 case OF_RECONFIG_DETACH_NODE:
546 memset(&rd, 0, sizeof(rd));
547 rd.dn = ce->np;
548 ret = of_reconfig_notify(ce->action, &rd);
549 break;
550 case OF_RECONFIG_ADD_PROPERTY:
551 case OF_RECONFIG_REMOVE_PROPERTY:
552 case OF_RECONFIG_UPDATE_PROPERTY:
553 ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
554 break;
555 default:
556 pr_err("invalid devicetree changeset action: %i\n",
557 (int)ce->action);
558 ret = -EINVAL;
559 }
560
561 if (ret)
562 pr_err("changeset notifier error @%pOF\n", ce->np);
563 return ret;
564}
565
566static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
567{
568 struct property *old_prop, **propp;
569 unsigned long flags;
570 int ret = 0;
571
572 __of_changeset_entry_dump(ce);
573
574 raw_spin_lock_irqsave(&devtree_lock, flags);
575 switch (ce->action) {
576 case OF_RECONFIG_ATTACH_NODE:
577 __of_attach_node(ce->np);
578 break;
579 case OF_RECONFIG_DETACH_NODE:
580 __of_detach_node(ce->np);
581 break;
582 case OF_RECONFIG_ADD_PROPERTY:
583 /* If the property is in deadprops then it must be removed */
584 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
585 if (*propp == ce->prop) {
586 *propp = ce->prop->next;
587 ce->prop->next = NULL;
588 break;
589 }
590 }
591
592 ret = __of_add_property(ce->np, ce->prop);
593 if (ret) {
594 pr_err("changeset: add_property failed @%pOF/%s\n",
595 ce->np,
596 ce->prop->name);
597 break;
598 }
599 break;
600 case OF_RECONFIG_REMOVE_PROPERTY:
601 ret = __of_remove_property(ce->np, ce->prop);
602 if (ret) {
603 pr_err("changeset: remove_property failed @%pOF/%s\n",
604 ce->np,
605 ce->prop->name);
606 break;
607 }
608 break;
609
610 case OF_RECONFIG_UPDATE_PROPERTY:
611 /* If the property is in deadprops then it must be removed */
612 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
613 if (*propp == ce->prop) {
614 *propp = ce->prop->next;
615 ce->prop->next = NULL;
616 break;
617 }
618 }
619
620 ret = __of_update_property(ce->np, ce->prop, &old_prop);
621 if (ret) {
622 pr_err("changeset: update_property failed @%pOF/%s\n",
623 ce->np,
624 ce->prop->name);
625 break;
626 }
627 break;
628 default:
629 ret = -EINVAL;
630 }
631 raw_spin_unlock_irqrestore(&devtree_lock, flags);
632
633 if (ret)
634 return ret;
635
636 switch (ce->action) {
637 case OF_RECONFIG_ATTACH_NODE:
638 __of_attach_node_sysfs(ce->np);
639 break;
640 case OF_RECONFIG_DETACH_NODE:
641 __of_detach_node_sysfs(ce->np);
642 break;
643 case OF_RECONFIG_ADD_PROPERTY:
644 /* ignore duplicate names */
645 __of_add_property_sysfs(ce->np, ce->prop);
646 break;
647 case OF_RECONFIG_REMOVE_PROPERTY:
648 __of_remove_property_sysfs(ce->np, ce->prop);
649 break;
650 case OF_RECONFIG_UPDATE_PROPERTY:
651 __of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
652 break;
653 }
654
655 return 0;
656}
657
658static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
659{
660 struct of_changeset_entry ce_inverted;
661
662 __of_changeset_entry_invert(ce, &ce_inverted);
663 return __of_changeset_entry_apply(&ce_inverted);
664}
665
666/**
667 * of_changeset_init - Initialize a changeset for use
668 *
669 * @ocs: changeset pointer
670 *
671 * Initialize a changeset structure
672 */
673void of_changeset_init(struct of_changeset *ocs)
674{
675 memset(ocs, 0, sizeof(*ocs));
676 INIT_LIST_HEAD(&ocs->entries);
677}
678EXPORT_SYMBOL_GPL(of_changeset_init);
679
680/**
681 * of_changeset_destroy - Destroy a changeset
682 *
683 * @ocs: changeset pointer
684 *
685 * Destroys a changeset. Note that if a changeset is applied,
686 * its changes to the tree cannot be reverted.
687 */
688void of_changeset_destroy(struct of_changeset *ocs)
689{
690 struct of_changeset_entry *ce, *cen;
691
692 list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
693 __of_changeset_entry_destroy(ce);
694}
695EXPORT_SYMBOL_GPL(of_changeset_destroy);
696
697/*
698 * Apply the changeset entries in @ocs.
699 * If apply fails, an attempt is made to revert the entries that were
700 * successfully applied.
701 *
702 * If multiple revert errors occur then only the final revert error is reported.
703 *
704 * Returns 0 on success, a negative error value in case of an error.
705 * If a revert error occurs, it is returned in *ret_revert.
706 */
707int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
708{
709 struct of_changeset_entry *ce;
710 int ret, ret_tmp;
711
712 pr_debug("changeset: applying...\n");
713 list_for_each_entry(ce, &ocs->entries, node) {
714 ret = __of_changeset_entry_apply(ce);
715 if (ret) {
716 pr_err("Error applying changeset (%d)\n", ret);
717 list_for_each_entry_continue_reverse(ce, &ocs->entries,
718 node) {
719 ret_tmp = __of_changeset_entry_revert(ce);
720 if (ret_tmp)
721 *ret_revert = ret_tmp;
722 }
723 return ret;
724 }
725 }
726
727 return 0;
728}
729
730/*
731 * Returns 0 on success, a negative error value in case of an error.
732 *
733 * If multiple changeset entry notification errors occur then only the
734 * final notification error is reported.
735 */
736int __of_changeset_apply_notify(struct of_changeset *ocs)
737{
738 struct of_changeset_entry *ce;
739 int ret = 0, ret_tmp;
740
741 pr_debug("changeset: emitting notifiers.\n");
742
743 /* drop the global lock while emitting notifiers */
744 mutex_unlock(&of_mutex);
745 list_for_each_entry(ce, &ocs->entries, node) {
746 ret_tmp = __of_changeset_entry_notify(ce, 0);
747 if (ret_tmp)
748 ret = ret_tmp;
749 }
750 mutex_lock(&of_mutex);
751 pr_debug("changeset: notifiers sent.\n");
752
753 return ret;
754}
755
756/*
757 * Returns 0 on success, a negative error value in case of an error.
758 *
759 * If a changeset entry apply fails, an attempt is made to revert any
760 * previous entries in the changeset. If any of the reverts fails,
761 * that failure is not reported. Thus the state of the device tree
762 * is unknown if an apply error occurs.
763 */
764static int __of_changeset_apply(struct of_changeset *ocs)
765{
766 int ret, ret_revert = 0;
767
768 ret = __of_changeset_apply_entries(ocs, &ret_revert);
769 if (!ret)
770 ret = __of_changeset_apply_notify(ocs);
771
772 return ret;
773}
774
775/**
776 * of_changeset_apply - Applies a changeset
777 *
778 * @ocs: changeset pointer
779 *
780 * Applies a changeset to the live tree.
781 * Any side-effects of live tree state changes are applied here on
782 * success, like creation/destruction of devices and side-effects
783 * like creation of sysfs properties and directories.
784 * Returns 0 on success, a negative error value in case of an error.
785 * On error the partially applied effects are reverted.
786 */
787int of_changeset_apply(struct of_changeset *ocs)
788{
789 int ret;
790
791 mutex_lock(&of_mutex);
792 ret = __of_changeset_apply(ocs);
793 mutex_unlock(&of_mutex);
794
795 return ret;
796}
797EXPORT_SYMBOL_GPL(of_changeset_apply);
798
799/*
800 * Revert the changeset entries in @ocs.
801 * If revert fails, an attempt is made to re-apply the entries that were
802 * successfully removed.
803 *
804 * If multiple re-apply errors occur then only the final apply error is
805 * reported.
806 *
807 * Returns 0 on success, a negative error value in case of an error.
808 * If an apply error occurs, it is returned in *ret_apply.
809 */
810int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
811{
812 struct of_changeset_entry *ce;
813 int ret, ret_tmp;
814
815 pr_debug("changeset: reverting...\n");
816 list_for_each_entry_reverse(ce, &ocs->entries, node) {
817 ret = __of_changeset_entry_revert(ce);
818 if (ret) {
819 pr_err("Error reverting changeset (%d)\n", ret);
820 list_for_each_entry_continue(ce, &ocs->entries, node) {
821 ret_tmp = __of_changeset_entry_apply(ce);
822 if (ret_tmp)
823 *ret_apply = ret_tmp;
824 }
825 return ret;
826 }
827 }
828
829 return 0;
830}
831
832/*
833 * If multiple changeset entry notification errors occur then only the
834 * final notification error is reported.
835 */
836int __of_changeset_revert_notify(struct of_changeset *ocs)
837{
838 struct of_changeset_entry *ce;
839 int ret = 0, ret_tmp;
840
841 pr_debug("changeset: emitting notifiers.\n");
842
843 /* drop the global lock while emitting notifiers */
844 mutex_unlock(&of_mutex);
845 list_for_each_entry_reverse(ce, &ocs->entries, node) {
846 ret_tmp = __of_changeset_entry_notify(ce, 1);
847 if (ret_tmp)
848 ret = ret_tmp;
849 }
850 mutex_lock(&of_mutex);
851 pr_debug("changeset: notifiers sent.\n");
852
853 return ret;
854}
855
856static int __of_changeset_revert(struct of_changeset *ocs)
857{
858 int ret, ret_reply;
859
860 ret_reply = 0;
861 ret = __of_changeset_revert_entries(ocs, &ret_reply);
862
863 if (!ret)
864 ret = __of_changeset_revert_notify(ocs);
865
866 return ret;
867}
868
869/**
870 * of_changeset_revert - Reverts an applied changeset
871 *
872 * @ocs: changeset pointer
873 *
874 * Reverts a changeset returning the state of the tree to what it
875 * was before the application.
876 * Any side-effects like creation/destruction of devices and
877 * removal of sysfs properties and directories are applied.
878 * Returns 0 on success, a negative error value in case of an error.
879 */
880int of_changeset_revert(struct of_changeset *ocs)
881{
882 int ret;
883
884 mutex_lock(&of_mutex);
885 ret = __of_changeset_revert(ocs);
886 mutex_unlock(&of_mutex);
887
888 return ret;
889}
890EXPORT_SYMBOL_GPL(of_changeset_revert);
891
892/**
893 * of_changeset_action - Add an action to the tail of the changeset list
894 *
895 * @ocs: changeset pointer
896 * @action: action to perform
897 * @np: Pointer to device node
898 * @prop: Pointer to property
899 *
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
906 * Returns 0 on success, a negative error value in case of an error.
907 */
908int of_changeset_action(struct of_changeset *ocs, unsigned long action,
909 struct device_node *np, struct property *prop)
910{
911 struct of_changeset_entry *ce;
912
913 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
914 if (!ce)
915 return -ENOMEM;
916
917 /* get a reference to the node */
918 ce->action = action;
919 ce->np = of_node_get(np);
920 ce->prop = prop;
921
922 if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
923 ce->old_prop = of_find_property(np, prop->name, NULL);
924
925 /* add it to the list */
926 list_add_tail(&ce->node, &ocs->entries);
927 return 0;
928}
929EXPORT_SYMBOL_GPL(of_changeset_action);