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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/device.h>
13#include <linux/of.h>
14#include <linux/spinlock.h>
15#include <linux/slab.h>
16#include <linux/string.h>
17#include <linux/proc_fs.h>
18
19#include "of_private.h"
20
21static struct device_node *kobj_to_device_node(struct kobject *kobj)
22{
23 return container_of(kobj, struct device_node, kobj);
24}
25
26/**
27 * of_node_get() - Increment refcount of a node
28 * @node: Node to inc refcount, NULL is supported to simplify writing of
29 * callers
30 *
31 * Return: The node with refcount incremented.
32 */
33struct device_node *of_node_get(struct device_node *node)
34{
35 if (node)
36 kobject_get(&node->kobj);
37 return node;
38}
39EXPORT_SYMBOL(of_node_get);
40
41/**
42 * of_node_put() - Decrement refcount of a node
43 * @node: Node to dec refcount, NULL is supported to simplify writing of
44 * callers
45 */
46void of_node_put(struct device_node *node)
47{
48 if (node)
49 kobject_put(&node->kobj);
50}
51EXPORT_SYMBOL(of_node_put);
52
53static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
54
55int of_reconfig_notifier_register(struct notifier_block *nb)
56{
57 return blocking_notifier_chain_register(&of_reconfig_chain, nb);
58}
59EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
60
61int of_reconfig_notifier_unregister(struct notifier_block *nb)
62{
63 return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
64}
65EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
66
67static const char *action_names[] = {
68 [0] = "INVALID",
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",
74};
75
76#define _do_print(func, prefix, action, node, prop, ...) ({ \
77 func("changeset: " prefix "%-15s %pOF%s%s\n", \
78 ##__VA_ARGS__, action_names[action], node, \
79 prop ? ":" : "", prop ? prop->name : ""); \
80})
81#define of_changeset_action_err(...) _do_print(pr_err, __VA_ARGS__)
82#define of_changeset_action_debug(...) _do_print(pr_debug, __VA_ARGS__)
83
84int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
85{
86 int rc;
87 struct of_reconfig_data *pr = p;
88
89 of_changeset_action_debug("notify: ", action, pr->dn, pr->prop);
90
91 rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
92 return notifier_to_errno(rc);
93}
94
95/*
96 * of_reconfig_get_state_change() - Returns new state of device
97 * @action - action of the of notifier
98 * @arg - argument of the of notifier
99 *
100 * Returns the new state of a device based on the notifier used.
101 *
102 * Return: OF_RECONFIG_CHANGE_REMOVE on device going from enabled to
103 * disabled, OF_RECONFIG_CHANGE_ADD on device going from disabled to
104 * enabled and OF_RECONFIG_NO_CHANGE on no change.
105 */
106int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr)
107{
108 struct property *prop, *old_prop = NULL;
109 int is_status, status_state, old_status_state, prev_state, new_state;
110
111 /* figure out if a device should be created or destroyed */
112 switch (action) {
113 case OF_RECONFIG_ATTACH_NODE:
114 case OF_RECONFIG_DETACH_NODE:
115 prop = of_find_property(pr->dn, "status", NULL);
116 break;
117 case OF_RECONFIG_ADD_PROPERTY:
118 case OF_RECONFIG_REMOVE_PROPERTY:
119 prop = pr->prop;
120 break;
121 case OF_RECONFIG_UPDATE_PROPERTY:
122 prop = pr->prop;
123 old_prop = pr->old_prop;
124 break;
125 default:
126 return OF_RECONFIG_NO_CHANGE;
127 }
128
129 is_status = 0;
130 status_state = -1;
131 old_status_state = -1;
132 prev_state = -1;
133 new_state = -1;
134
135 if (prop && !strcmp(prop->name, "status")) {
136 is_status = 1;
137 status_state = !strcmp(prop->value, "okay") ||
138 !strcmp(prop->value, "ok");
139 if (old_prop)
140 old_status_state = !strcmp(old_prop->value, "okay") ||
141 !strcmp(old_prop->value, "ok");
142 }
143
144 switch (action) {
145 case OF_RECONFIG_ATTACH_NODE:
146 prev_state = 0;
147 /* -1 & 0 status either missing or okay */
148 new_state = status_state != 0;
149 break;
150 case OF_RECONFIG_DETACH_NODE:
151 /* -1 & 0 status either missing or okay */
152 prev_state = status_state != 0;
153 new_state = 0;
154 break;
155 case OF_RECONFIG_ADD_PROPERTY:
156 if (is_status) {
157 /* no status property -> enabled (legacy) */
158 prev_state = 1;
159 new_state = status_state;
160 }
161 break;
162 case OF_RECONFIG_REMOVE_PROPERTY:
163 if (is_status) {
164 prev_state = status_state;
165 /* no status property -> enabled (legacy) */
166 new_state = 1;
167 }
168 break;
169 case OF_RECONFIG_UPDATE_PROPERTY:
170 if (is_status) {
171 prev_state = old_status_state != 0;
172 new_state = status_state != 0;
173 }
174 break;
175 }
176
177 if (prev_state == new_state)
178 return OF_RECONFIG_NO_CHANGE;
179
180 return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
181}
182EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
183
184int of_property_notify(int action, struct device_node *np,
185 struct property *prop, struct property *oldprop)
186{
187 struct of_reconfig_data pr;
188
189 /* only call notifiers if the node is attached */
190 if (!of_node_is_attached(np))
191 return 0;
192
193 pr.dn = np;
194 pr.prop = prop;
195 pr.old_prop = oldprop;
196 return of_reconfig_notify(action, &pr);
197}
198
199static void __of_attach_node(struct device_node *np)
200{
201 const __be32 *phandle;
202 int sz;
203 unsigned long flags;
204
205 raw_spin_lock_irqsave(&devtree_lock, flags);
206
207 if (!of_node_check_flag(np, OF_OVERLAY)) {
208 np->name = __of_get_property(np, "name", NULL);
209 if (!np->name)
210 np->name = "<NULL>";
211
212 phandle = __of_get_property(np, "phandle", &sz);
213 if (!phandle)
214 phandle = __of_get_property(np, "linux,phandle", &sz);
215 if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
216 phandle = __of_get_property(np, "ibm,phandle", &sz);
217 if (phandle && (sz >= 4))
218 np->phandle = be32_to_cpup(phandle);
219 else
220 np->phandle = 0;
221 }
222
223 np->child = NULL;
224 np->sibling = np->parent->child;
225 np->parent->child = np;
226 of_node_clear_flag(np, OF_DETACHED);
227 np->fwnode.flags |= FWNODE_FLAG_NOT_DEVICE;
228
229 raw_spin_unlock_irqrestore(&devtree_lock, flags);
230
231 __of_attach_node_sysfs(np);
232}
233
234/**
235 * of_attach_node() - Plug a device node into the tree and global list.
236 * @np: Pointer to the caller's Device Node
237 */
238int of_attach_node(struct device_node *np)
239{
240 struct of_reconfig_data rd;
241
242 memset(&rd, 0, sizeof(rd));
243 rd.dn = np;
244
245 mutex_lock(&of_mutex);
246 __of_attach_node(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 unsigned long flags;
258
259 raw_spin_lock_irqsave(&devtree_lock, flags);
260
261 parent = np->parent;
262 if (WARN_ON(of_node_check_flag(np, OF_DETACHED) || !parent)) {
263 raw_spin_unlock_irqrestore(&devtree_lock, flags);
264 return;
265 }
266
267 if (parent->child == np)
268 parent->child = np->sibling;
269 else {
270 struct device_node *prevsib;
271 for (prevsib = np->parent->child;
272 prevsib->sibling != np;
273 prevsib = prevsib->sibling)
274 ;
275 prevsib->sibling = np->sibling;
276 }
277
278 of_node_set_flag(np, OF_DETACHED);
279
280 /* race with of_find_node_by_phandle() prevented by devtree_lock */
281 __of_phandle_cache_inv_entry(np->phandle);
282
283 raw_spin_unlock_irqrestore(&devtree_lock, flags);
284
285 __of_detach_node_sysfs(np);
286}
287
288/**
289 * of_detach_node() - "Unplug" a node from the device tree.
290 * @np: Pointer to the caller's Device Node
291 */
292int of_detach_node(struct device_node *np)
293{
294 struct of_reconfig_data rd;
295
296 memset(&rd, 0, sizeof(rd));
297 rd.dn = np;
298
299 mutex_lock(&of_mutex);
300 __of_detach_node(np);
301 mutex_unlock(&of_mutex);
302
303 of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
304
305 return 0;
306}
307EXPORT_SYMBOL_GPL(of_detach_node);
308
309static void property_list_free(struct property *prop_list)
310{
311 struct property *prop, *next;
312
313 for (prop = prop_list; prop != NULL; prop = next) {
314 next = prop->next;
315 kfree(prop->name);
316 kfree(prop->value);
317 kfree(prop);
318 }
319}
320
321/**
322 * of_node_release() - release a dynamically allocated node
323 * @kobj: kernel object of the node to be released
324 *
325 * In of_node_put() this function is passed to kref_put() as the destructor.
326 */
327void of_node_release(struct kobject *kobj)
328{
329 struct device_node *node = kobj_to_device_node(kobj);
330
331 /*
332 * can not use '"%pOF", node' in pr_err() calls from this function
333 * because an of_node_get(node) when refcount is already zero
334 * will result in an error and a stack dump
335 */
336
337 /* We should never be releasing nodes that haven't been detached. */
338 if (!of_node_check_flag(node, OF_DETACHED)) {
339
340 pr_err("ERROR: %s() detected bad of_node_put() on %pOF/%s\n",
341 __func__, node->parent, node->full_name);
342
343 /*
344 * of unittests will test this path. Do not print the stack
345 * trace when the error is caused by unittest so that we do
346 * not display what a normal developer might reasonably
347 * consider a real bug.
348 */
349 if (!IS_ENABLED(CONFIG_OF_UNITTEST) ||
350 strcmp(node->parent->full_name, "testcase-data")) {
351 dump_stack();
352 pr_err("ERROR: next of_node_put() on this node will result in a kobject warning 'refcount_t: underflow; use-after-free.'\n");
353 }
354
355 return;
356 }
357 if (!of_node_check_flag(node, OF_DYNAMIC))
358 return;
359
360 if (of_node_check_flag(node, OF_OVERLAY)) {
361
362 if (!of_node_check_flag(node, OF_OVERLAY_FREE_CSET)) {
363 /* premature refcount of zero, do not free memory */
364 pr_err("ERROR: memory leak before free overlay changeset, %pOF\n",
365 node);
366 return;
367 }
368
369 /*
370 * If node->properties non-empty then properties were added
371 * to this node either by different overlay that has not
372 * yet been removed, or by a non-overlay mechanism.
373 */
374 if (node->properties)
375 pr_err("ERROR: %s(), unexpected properties in %pOF\n",
376 __func__, node);
377 }
378
379 if (node->child)
380 pr_err("ERROR: %s() unexpected children for %pOF/%s\n",
381 __func__, node->parent, node->full_name);
382
383 property_list_free(node->properties);
384 property_list_free(node->deadprops);
385 fwnode_links_purge(of_fwnode_handle(node));
386
387 kfree(node->full_name);
388 kfree(node->data);
389 kfree(node);
390}
391
392/**
393 * __of_prop_dup - Copy a property dynamically.
394 * @prop: Property to copy
395 * @allocflags: Allocation flags (typically pass GFP_KERNEL)
396 *
397 * Copy a property by dynamically allocating the memory of both the
398 * property structure and the property name & contents. The property's
399 * flags have the OF_DYNAMIC bit set so that we can differentiate between
400 * dynamically allocated properties and not.
401 *
402 * Return: The newly allocated property or NULL on out of memory error.
403 */
404struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
405{
406 struct property *new;
407
408 new = kzalloc(sizeof(*new), allocflags);
409 if (!new)
410 return NULL;
411
412 /*
413 * NOTE: There is no check for zero length value.
414 * In case of a boolean property, this will allocate a value
415 * of zero bytes. We do this to work around the use
416 * of of_get_property() calls on boolean values.
417 */
418 new->name = kstrdup(prop->name, allocflags);
419 new->value = kmemdup(prop->value, prop->length, allocflags);
420 new->length = prop->length;
421 if (!new->name || !new->value)
422 goto err_free;
423
424 /* mark the property as dynamic */
425 of_property_set_flag(new, OF_DYNAMIC);
426
427 return new;
428
429 err_free:
430 kfree(new->name);
431 kfree(new->value);
432 kfree(new);
433 return NULL;
434}
435
436/**
437 * __of_node_dup() - Duplicate or create an empty device node dynamically.
438 * @np: if not NULL, contains properties to be duplicated in new node
439 * @full_name: string value to be duplicated into new node's full_name field
440 *
441 * Create a device tree node, optionally duplicating the properties of
442 * another node. The node data are dynamically allocated and all the node
443 * flags have the OF_DYNAMIC & OF_DETACHED bits set.
444 *
445 * Return: The newly allocated node or NULL on out of memory error. Use
446 * of_node_put() on it when done to free the memory allocated for it.
447 */
448struct device_node *__of_node_dup(const struct device_node *np,
449 const char *full_name)
450{
451 struct device_node *node;
452
453 node = kzalloc(sizeof(*node), GFP_KERNEL);
454 if (!node)
455 return NULL;
456 node->full_name = kstrdup(full_name, GFP_KERNEL);
457 if (!node->full_name) {
458 kfree(node);
459 return NULL;
460 }
461
462 of_node_set_flag(node, OF_DYNAMIC);
463 of_node_set_flag(node, OF_DETACHED);
464 of_node_init(node);
465
466 /* Iterate over and duplicate all properties */
467 if (np) {
468 struct property *pp, *new_pp;
469 for_each_property_of_node(np, pp) {
470 new_pp = __of_prop_dup(pp, GFP_KERNEL);
471 if (!new_pp)
472 goto err_prop;
473 if (__of_add_property(node, new_pp)) {
474 kfree(new_pp->name);
475 kfree(new_pp->value);
476 kfree(new_pp);
477 goto err_prop;
478 }
479 }
480 }
481 return node;
482
483 err_prop:
484 of_node_put(node); /* Frees the node and properties */
485 return NULL;
486}
487
488/**
489 * of_changeset_create_node - Dynamically create a device node and attach to
490 * a given changeset.
491 *
492 * @ocs: Pointer to changeset
493 * @parent: Pointer to parent device node
494 * @full_name: Node full name
495 *
496 * Return: Pointer to the created device node or NULL in case of an error.
497 */
498struct device_node *of_changeset_create_node(struct of_changeset *ocs,
499 struct device_node *parent,
500 const char *full_name)
501{
502 struct device_node *np;
503 int ret;
504
505 np = __of_node_dup(NULL, full_name);
506 if (!np)
507 return NULL;
508 np->parent = parent;
509
510 ret = of_changeset_attach_node(ocs, np);
511 if (ret) {
512 of_node_put(np);
513 return NULL;
514 }
515
516 return np;
517}
518EXPORT_SYMBOL(of_changeset_create_node);
519
520static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
521{
522 if (ce->action == OF_RECONFIG_ATTACH_NODE &&
523 of_node_check_flag(ce->np, OF_OVERLAY)) {
524 if (kref_read(&ce->np->kobj.kref) > 1) {
525 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",
526 kref_read(&ce->np->kobj.kref), ce->np);
527 } else {
528 of_node_set_flag(ce->np, OF_OVERLAY_FREE_CSET);
529 }
530 }
531
532 of_node_put(ce->np);
533 list_del(&ce->node);
534 kfree(ce);
535}
536
537static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
538 struct of_changeset_entry *rce)
539{
540 memcpy(rce, ce, sizeof(*rce));
541
542 switch (ce->action) {
543 case OF_RECONFIG_ATTACH_NODE:
544 rce->action = OF_RECONFIG_DETACH_NODE;
545 break;
546 case OF_RECONFIG_DETACH_NODE:
547 rce->action = OF_RECONFIG_ATTACH_NODE;
548 break;
549 case OF_RECONFIG_ADD_PROPERTY:
550 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
551 break;
552 case OF_RECONFIG_REMOVE_PROPERTY:
553 rce->action = OF_RECONFIG_ADD_PROPERTY;
554 break;
555 case OF_RECONFIG_UPDATE_PROPERTY:
556 rce->old_prop = ce->prop;
557 rce->prop = ce->old_prop;
558 /* update was used but original property did not exist */
559 if (!rce->prop) {
560 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
561 rce->prop = ce->prop;
562 }
563 break;
564 }
565}
566
567static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
568 bool revert)
569{
570 struct of_reconfig_data rd;
571 struct of_changeset_entry ce_inverted;
572 int ret = 0;
573
574 if (revert) {
575 __of_changeset_entry_invert(ce, &ce_inverted);
576 ce = &ce_inverted;
577 }
578
579 switch (ce->action) {
580 case OF_RECONFIG_ATTACH_NODE:
581 case OF_RECONFIG_DETACH_NODE:
582 memset(&rd, 0, sizeof(rd));
583 rd.dn = ce->np;
584 ret = of_reconfig_notify(ce->action, &rd);
585 break;
586 case OF_RECONFIG_ADD_PROPERTY:
587 case OF_RECONFIG_REMOVE_PROPERTY:
588 case OF_RECONFIG_UPDATE_PROPERTY:
589 ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
590 break;
591 default:
592 pr_err("invalid devicetree changeset action: %i\n",
593 (int)ce->action);
594 ret = -EINVAL;
595 }
596
597 if (ret)
598 pr_err("changeset notifier error @%pOF\n", ce->np);
599 return ret;
600}
601
602static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
603{
604 int ret = 0;
605
606 of_changeset_action_debug("apply: ", ce->action, ce->np, ce->prop);
607
608 switch (ce->action) {
609 case OF_RECONFIG_ATTACH_NODE:
610 __of_attach_node(ce->np);
611 break;
612 case OF_RECONFIG_DETACH_NODE:
613 __of_detach_node(ce->np);
614 break;
615 case OF_RECONFIG_ADD_PROPERTY:
616 ret = __of_add_property(ce->np, ce->prop);
617 break;
618 case OF_RECONFIG_REMOVE_PROPERTY:
619 ret = __of_remove_property(ce->np, ce->prop);
620 break;
621
622 case OF_RECONFIG_UPDATE_PROPERTY:
623 ret = __of_update_property(ce->np, ce->prop, &ce->old_prop);
624 break;
625 default:
626 ret = -EINVAL;
627 }
628
629 if (ret) {
630 of_changeset_action_err("apply failed: ", ce->action, ce->np, ce->prop);
631 return ret;
632 }
633
634 return 0;
635}
636
637static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
638{
639 struct of_changeset_entry ce_inverted;
640
641 __of_changeset_entry_invert(ce, &ce_inverted);
642 return __of_changeset_entry_apply(&ce_inverted);
643}
644
645/**
646 * of_changeset_init - Initialize a changeset for use
647 *
648 * @ocs: changeset pointer
649 *
650 * Initialize a changeset structure
651 */
652void of_changeset_init(struct of_changeset *ocs)
653{
654 memset(ocs, 0, sizeof(*ocs));
655 INIT_LIST_HEAD(&ocs->entries);
656}
657EXPORT_SYMBOL_GPL(of_changeset_init);
658
659/**
660 * of_changeset_destroy - Destroy a changeset
661 *
662 * @ocs: changeset pointer
663 *
664 * Destroys a changeset. Note that if a changeset is applied,
665 * its changes to the tree cannot be reverted.
666 */
667void of_changeset_destroy(struct of_changeset *ocs)
668{
669 struct of_changeset_entry *ce, *cen;
670
671 /*
672 * When a device is deleted, the device links to/from it are also queued
673 * for deletion. Until these device links are freed, the devices
674 * themselves aren't freed. If the device being deleted is due to an
675 * overlay change, this device might be holding a reference to a device
676 * node that will be freed. So, wait until all already pending device
677 * links are deleted before freeing a device node. This ensures we don't
678 * free any device node that has a non-zero reference count.
679 */
680 device_link_wait_removal();
681
682 list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
683 __of_changeset_entry_destroy(ce);
684}
685EXPORT_SYMBOL_GPL(of_changeset_destroy);
686
687/*
688 * Apply the changeset entries in @ocs.
689 * If apply fails, an attempt is made to revert the entries that were
690 * successfully applied.
691 *
692 * If multiple revert errors occur then only the final revert error is reported.
693 *
694 * Returns 0 on success, a negative error value in case of an error.
695 * If a revert error occurs, it is returned in *ret_revert.
696 */
697int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
698{
699 struct of_changeset_entry *ce;
700 int ret, ret_tmp;
701
702 pr_debug("changeset: applying...\n");
703 list_for_each_entry(ce, &ocs->entries, node) {
704 ret = __of_changeset_entry_apply(ce);
705 if (ret) {
706 pr_err("Error applying changeset (%d)\n", ret);
707 list_for_each_entry_continue_reverse(ce, &ocs->entries,
708 node) {
709 ret_tmp = __of_changeset_entry_revert(ce);
710 if (ret_tmp)
711 *ret_revert = ret_tmp;
712 }
713 return ret;
714 }
715 }
716
717 return 0;
718}
719
720/*
721 * Returns 0 on success, a negative error value in case of an error.
722 *
723 * If multiple changeset entry notification errors occur then only the
724 * final notification error is reported.
725 */
726int __of_changeset_apply_notify(struct of_changeset *ocs)
727{
728 struct of_changeset_entry *ce;
729 int ret = 0, ret_tmp;
730
731 pr_debug("changeset: emitting notifiers.\n");
732
733 /* drop the global lock while emitting notifiers */
734 mutex_unlock(&of_mutex);
735 list_for_each_entry(ce, &ocs->entries, node) {
736 ret_tmp = __of_changeset_entry_notify(ce, 0);
737 if (ret_tmp)
738 ret = ret_tmp;
739 }
740 mutex_lock(&of_mutex);
741 pr_debug("changeset: notifiers sent.\n");
742
743 return ret;
744}
745
746/*
747 * Returns 0 on success, a negative error value in case of an error.
748 *
749 * If a changeset entry apply fails, an attempt is made to revert any
750 * previous entries in the changeset. If any of the reverts fails,
751 * that failure is not reported. Thus the state of the device tree
752 * is unknown if an apply error occurs.
753 */
754static int __of_changeset_apply(struct of_changeset *ocs)
755{
756 int ret, ret_revert = 0;
757
758 ret = __of_changeset_apply_entries(ocs, &ret_revert);
759 if (!ret)
760 ret = __of_changeset_apply_notify(ocs);
761
762 return ret;
763}
764
765/**
766 * of_changeset_apply - Applies a changeset
767 *
768 * @ocs: changeset pointer
769 *
770 * Applies a changeset to the live tree.
771 * Any side-effects of live tree state changes are applied here on
772 * success, like creation/destruction of devices and side-effects
773 * like creation of sysfs properties and directories.
774 *
775 * Return: 0 on success, a negative error value in case of an error.
776 * On error the partially applied effects are reverted.
777 */
778int of_changeset_apply(struct of_changeset *ocs)
779{
780 int ret;
781
782 mutex_lock(&of_mutex);
783 ret = __of_changeset_apply(ocs);
784 mutex_unlock(&of_mutex);
785
786 return ret;
787}
788EXPORT_SYMBOL_GPL(of_changeset_apply);
789
790/*
791 * Revert the changeset entries in @ocs.
792 * If revert fails, an attempt is made to re-apply the entries that were
793 * successfully removed.
794 *
795 * If multiple re-apply errors occur then only the final apply error is
796 * reported.
797 *
798 * Returns 0 on success, a negative error value in case of an error.
799 * If an apply error occurs, it is returned in *ret_apply.
800 */
801int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
802{
803 struct of_changeset_entry *ce;
804 int ret, ret_tmp;
805
806 pr_debug("changeset: reverting...\n");
807 list_for_each_entry_reverse(ce, &ocs->entries, node) {
808 ret = __of_changeset_entry_revert(ce);
809 if (ret) {
810 pr_err("Error reverting changeset (%d)\n", ret);
811 list_for_each_entry_continue(ce, &ocs->entries, node) {
812 ret_tmp = __of_changeset_entry_apply(ce);
813 if (ret_tmp)
814 *ret_apply = ret_tmp;
815 }
816 return ret;
817 }
818 }
819
820 return 0;
821}
822
823/*
824 * If multiple changeset entry notification errors occur then only the
825 * final notification error is reported.
826 */
827int __of_changeset_revert_notify(struct of_changeset *ocs)
828{
829 struct of_changeset_entry *ce;
830 int ret = 0, ret_tmp;
831
832 pr_debug("changeset: emitting notifiers.\n");
833
834 /* drop the global lock while emitting notifiers */
835 mutex_unlock(&of_mutex);
836 list_for_each_entry_reverse(ce, &ocs->entries, node) {
837 ret_tmp = __of_changeset_entry_notify(ce, 1);
838 if (ret_tmp)
839 ret = ret_tmp;
840 }
841 mutex_lock(&of_mutex);
842 pr_debug("changeset: notifiers sent.\n");
843
844 return ret;
845}
846
847static int __of_changeset_revert(struct of_changeset *ocs)
848{
849 int ret, ret_reply;
850
851 ret_reply = 0;
852 ret = __of_changeset_revert_entries(ocs, &ret_reply);
853
854 if (!ret)
855 ret = __of_changeset_revert_notify(ocs);
856
857 return ret;
858}
859
860/**
861 * of_changeset_revert - Reverts an applied changeset
862 *
863 * @ocs: changeset pointer
864 *
865 * Reverts a changeset returning the state of the tree to what it
866 * was before the application.
867 * Any side-effects like creation/destruction of devices and
868 * removal of sysfs properties and directories are applied.
869 *
870 * Return: 0 on success, a negative error value in case of an error.
871 */
872int of_changeset_revert(struct of_changeset *ocs)
873{
874 int ret;
875
876 mutex_lock(&of_mutex);
877 ret = __of_changeset_revert(ocs);
878 mutex_unlock(&of_mutex);
879
880 return ret;
881}
882EXPORT_SYMBOL_GPL(of_changeset_revert);
883
884/**
885 * of_changeset_action - Add an action to the tail of the changeset list
886 *
887 * @ocs: changeset pointer
888 * @action: action to perform
889 * @np: Pointer to device node
890 * @prop: Pointer to property
891 *
892 * On action being one of:
893 * + OF_RECONFIG_ATTACH_NODE
894 * + OF_RECONFIG_DETACH_NODE,
895 * + OF_RECONFIG_ADD_PROPERTY
896 * + OF_RECONFIG_REMOVE_PROPERTY,
897 * + OF_RECONFIG_UPDATE_PROPERTY
898 *
899 * Return: 0 on success, a negative error value in case of an error.
900 */
901int of_changeset_action(struct of_changeset *ocs, unsigned long action,
902 struct device_node *np, struct property *prop)
903{
904 struct of_changeset_entry *ce;
905
906 if (WARN_ON(action >= ARRAY_SIZE(action_names)))
907 return -EINVAL;
908
909 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
910 if (!ce)
911 return -ENOMEM;
912
913 /* get a reference to the node */
914 ce->action = action;
915 ce->np = of_node_get(np);
916 ce->prop = prop;
917
918 /* add it to the list */
919 list_add_tail(&ce->node, &ocs->entries);
920 return 0;
921}
922EXPORT_SYMBOL_GPL(of_changeset_action);
923
924static int of_changeset_add_prop_helper(struct of_changeset *ocs,
925 struct device_node *np,
926 const struct property *pp)
927{
928 struct property *new_pp;
929 int ret;
930
931 new_pp = __of_prop_dup(pp, GFP_KERNEL);
932 if (!new_pp)
933 return -ENOMEM;
934
935 ret = of_changeset_add_property(ocs, np, new_pp);
936 if (ret) {
937 kfree(new_pp->name);
938 kfree(new_pp->value);
939 kfree(new_pp);
940 }
941
942 return ret;
943}
944
945/**
946 * of_changeset_add_prop_string - Add a string property to a changeset
947 *
948 * @ocs: changeset pointer
949 * @np: device node pointer
950 * @prop_name: name of the property to be added
951 * @str: pointer to null terminated string
952 *
953 * Create a string property and add it to a changeset.
954 *
955 * Return: 0 on success, a negative error value in case of an error.
956 */
957int of_changeset_add_prop_string(struct of_changeset *ocs,
958 struct device_node *np,
959 const char *prop_name, const char *str)
960{
961 struct property prop;
962
963 prop.name = (char *)prop_name;
964 prop.length = strlen(str) + 1;
965 prop.value = (void *)str;
966
967 return of_changeset_add_prop_helper(ocs, np, &prop);
968}
969EXPORT_SYMBOL_GPL(of_changeset_add_prop_string);
970
971/**
972 * of_changeset_add_prop_string_array - Add a string list property to
973 * a changeset
974 *
975 * @ocs: changeset pointer
976 * @np: device node pointer
977 * @prop_name: name of the property to be added
978 * @str_array: pointer to an array of null terminated strings
979 * @sz: number of string array elements
980 *
981 * Create a string list property and add it to a changeset.
982 *
983 * Return: 0 on success, a negative error value in case of an error.
984 */
985int of_changeset_add_prop_string_array(struct of_changeset *ocs,
986 struct device_node *np,
987 const char *prop_name,
988 const char **str_array, size_t sz)
989{
990 struct property prop;
991 int i, ret;
992 char *vp;
993
994 prop.name = (char *)prop_name;
995
996 prop.length = 0;
997 for (i = 0; i < sz; i++)
998 prop.length += strlen(str_array[i]) + 1;
999
1000 prop.value = kmalloc(prop.length, GFP_KERNEL);
1001 if (!prop.value)
1002 return -ENOMEM;
1003
1004 vp = prop.value;
1005 for (i = 0; i < sz; i++) {
1006 vp += snprintf(vp, (char *)prop.value + prop.length - vp, "%s",
1007 str_array[i]) + 1;
1008 }
1009 ret = of_changeset_add_prop_helper(ocs, np, &prop);
1010 kfree(prop.value);
1011
1012 return ret;
1013}
1014EXPORT_SYMBOL_GPL(of_changeset_add_prop_string_array);
1015
1016/**
1017 * of_changeset_add_prop_u32_array - Add a property of 32 bit integers
1018 * property to a changeset
1019 *
1020 * @ocs: changeset pointer
1021 * @np: device node pointer
1022 * @prop_name: name of the property to be added
1023 * @array: pointer to an array of 32 bit integers
1024 * @sz: number of array elements
1025 *
1026 * Create a property of 32 bit integers and add it to a changeset.
1027 *
1028 * Return: 0 on success, a negative error value in case of an error.
1029 */
1030int of_changeset_add_prop_u32_array(struct of_changeset *ocs,
1031 struct device_node *np,
1032 const char *prop_name,
1033 const u32 *array, size_t sz)
1034{
1035 struct property prop;
1036 __be32 *val;
1037 int i, ret;
1038
1039 val = kcalloc(sz, sizeof(__be32), GFP_KERNEL);
1040 if (!val)
1041 return -ENOMEM;
1042
1043 for (i = 0; i < sz; i++)
1044 val[i] = cpu_to_be32(array[i]);
1045 prop.name = (char *)prop_name;
1046 prop.length = sizeof(u32) * sz;
1047 prop.value = (void *)val;
1048
1049 ret = of_changeset_add_prop_helper(ocs, np, &prop);
1050 kfree(val);
1051
1052 return ret;
1053}
1054EXPORT_SYMBOL_GPL(of_changeset_add_prop_u32_array);