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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 * Return: The node with refcount incremented.
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 *
108 * Return: 0 on device going from enabled to disabled, 1 on device
109 * going from disabled to enabled and -1 on no change.
110 */
111int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr)
112{
113 struct property *prop, *old_prop = NULL;
114 int is_status, status_state, old_status_state, prev_state, new_state;
115
116 /* figure out if a device should be created or destroyed */
117 switch (action) {
118 case OF_RECONFIG_ATTACH_NODE:
119 case OF_RECONFIG_DETACH_NODE:
120 prop = of_find_property(pr->dn, "status", NULL);
121 break;
122 case OF_RECONFIG_ADD_PROPERTY:
123 case OF_RECONFIG_REMOVE_PROPERTY:
124 prop = pr->prop;
125 break;
126 case OF_RECONFIG_UPDATE_PROPERTY:
127 prop = pr->prop;
128 old_prop = pr->old_prop;
129 break;
130 default:
131 return OF_RECONFIG_NO_CHANGE;
132 }
133
134 is_status = 0;
135 status_state = -1;
136 old_status_state = -1;
137 prev_state = -1;
138 new_state = -1;
139
140 if (prop && !strcmp(prop->name, "status")) {
141 is_status = 1;
142 status_state = !strcmp(prop->value, "okay") ||
143 !strcmp(prop->value, "ok");
144 if (old_prop)
145 old_status_state = !strcmp(old_prop->value, "okay") ||
146 !strcmp(old_prop->value, "ok");
147 }
148
149 switch (action) {
150 case OF_RECONFIG_ATTACH_NODE:
151 prev_state = 0;
152 /* -1 & 0 status either missing or okay */
153 new_state = status_state != 0;
154 break;
155 case OF_RECONFIG_DETACH_NODE:
156 /* -1 & 0 status either missing or okay */
157 prev_state = status_state != 0;
158 new_state = 0;
159 break;
160 case OF_RECONFIG_ADD_PROPERTY:
161 if (is_status) {
162 /* no status property -> enabled (legacy) */
163 prev_state = 1;
164 new_state = status_state;
165 }
166 break;
167 case OF_RECONFIG_REMOVE_PROPERTY:
168 if (is_status) {
169 prev_state = status_state;
170 /* no status property -> enabled (legacy) */
171 new_state = 1;
172 }
173 break;
174 case OF_RECONFIG_UPDATE_PROPERTY:
175 if (is_status) {
176 prev_state = old_status_state != 0;
177 new_state = status_state != 0;
178 }
179 break;
180 }
181
182 if (prev_state == new_state)
183 return OF_RECONFIG_NO_CHANGE;
184
185 return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
186}
187EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
188
189int of_property_notify(int action, struct device_node *np,
190 struct property *prop, struct property *oldprop)
191{
192 struct of_reconfig_data pr;
193
194 /* only call notifiers if the node is attached */
195 if (!of_node_is_attached(np))
196 return 0;
197
198 pr.dn = np;
199 pr.prop = prop;
200 pr.old_prop = oldprop;
201 return of_reconfig_notify(action, &pr);
202}
203
204static void __of_attach_node(struct device_node *np)
205{
206 const __be32 *phandle;
207 int sz;
208
209 if (!of_node_check_flag(np, OF_OVERLAY)) {
210 np->name = __of_get_property(np, "name", NULL);
211 if (!np->name)
212 np->name = "<NULL>";
213
214 phandle = __of_get_property(np, "phandle", &sz);
215 if (!phandle)
216 phandle = __of_get_property(np, "linux,phandle", &sz);
217 if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
218 phandle = __of_get_property(np, "ibm,phandle", &sz);
219 if (phandle && (sz >= 4))
220 np->phandle = be32_to_cpup(phandle);
221 else
222 np->phandle = 0;
223 }
224
225 np->child = NULL;
226 np->sibling = np->parent->child;
227 np->parent->child = np;
228 of_node_clear_flag(np, OF_DETACHED);
229}
230
231/**
232 * of_attach_node() - Plug a device node into the tree and global list.
233 * @np: Pointer to the caller's Device Node
234 */
235int of_attach_node(struct device_node *np)
236{
237 struct of_reconfig_data rd;
238 unsigned long flags;
239
240 memset(&rd, 0, sizeof(rd));
241 rd.dn = np;
242
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);
247
248 __of_attach_node_sysfs(np);
249 mutex_unlock(&of_mutex);
250
251 of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);
252
253 return 0;
254}
255
256void __of_detach_node(struct device_node *np)
257{
258 struct device_node *parent;
259
260 if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
261 return;
262
263 parent = np->parent;
264 if (WARN_ON(!parent))
265 return;
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
284/**
285 * of_detach_node() - "Unplug" a node from the device tree.
286 * @np: Pointer to the caller's Device Node
287 */
288int of_detach_node(struct device_node *np)
289{
290 struct of_reconfig_data rd;
291 unsigned long flags;
292
293 memset(&rd, 0, sizeof(rd));
294 rd.dn = np;
295
296 mutex_lock(&of_mutex);
297 raw_spin_lock_irqsave(&devtree_lock, flags);
298 __of_detach_node(np);
299 raw_spin_unlock_irqrestore(&devtree_lock, flags);
300
301 __of_detach_node_sysfs(np);
302 mutex_unlock(&of_mutex);
303
304 of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
305
306 return 0;
307}
308EXPORT_SYMBOL_GPL(of_detach_node);
309
310static void property_list_free(struct property *prop_list)
311{
312 struct property *prop, *next;
313
314 for (prop = prop_list; prop != NULL; prop = next) {
315 next = prop->next;
316 kfree(prop->name);
317 kfree(prop->value);
318 kfree(prop);
319 }
320}
321
322/**
323 * of_node_release() - release a dynamically allocated node
324 * @kobj: kernel object of the node to be released
325 *
326 * In of_node_put() this function is passed to kref_put() as the destructor.
327 */
328void of_node_release(struct kobject *kobj)
329{
330 struct device_node *node = kobj_to_device_node(kobj);
331
332 /* We should never be releasing nodes that haven't been detached. */
333 if (!of_node_check_flag(node, OF_DETACHED)) {
334 pr_err("ERROR: Bad of_node_put() on %pOF\n", node);
335 dump_stack();
336 return;
337 }
338 if (!of_node_check_flag(node, OF_DYNAMIC))
339 return;
340
341 if (of_node_check_flag(node, OF_OVERLAY)) {
342
343 if (!of_node_check_flag(node, OF_OVERLAY_FREE_CSET)) {
344 /* premature refcount of zero, do not free memory */
345 pr_err("ERROR: memory leak before free overlay changeset, %pOF\n",
346 node);
347 return;
348 }
349
350 /*
351 * If node->properties non-empty then properties were added
352 * to this node either by different overlay that has not
353 * yet been removed, or by a non-overlay mechanism.
354 */
355 if (node->properties)
356 pr_err("ERROR: %s(), unexpected properties in %pOF\n",
357 __func__, node);
358 }
359
360 property_list_free(node->properties);
361 property_list_free(node->deadprops);
362 fwnode_links_purge(of_fwnode_handle(node));
363
364 kfree(node->full_name);
365 kfree(node->data);
366 kfree(node);
367}
368
369/**
370 * __of_prop_dup - Copy a property dynamically.
371 * @prop: Property to copy
372 * @allocflags: Allocation flags (typically pass GFP_KERNEL)
373 *
374 * Copy a property by dynamically allocating the memory of both the
375 * property structure and the property name & contents. The property's
376 * flags have the OF_DYNAMIC bit set so that we can differentiate between
377 * dynamically allocated properties and not.
378 *
379 * Return: The newly allocated property or NULL on out of memory error.
380 */
381struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
382{
383 struct property *new;
384
385 new = kzalloc(sizeof(*new), allocflags);
386 if (!new)
387 return NULL;
388
389 /*
390 * NOTE: There is no check for zero length value.
391 * In case of a boolean property, this will allocate a value
392 * of zero bytes. We do this to work around the use
393 * of of_get_property() calls on boolean values.
394 */
395 new->name = kstrdup(prop->name, allocflags);
396 new->value = kmemdup(prop->value, prop->length, allocflags);
397 new->length = prop->length;
398 if (!new->name || !new->value)
399 goto err_free;
400
401 /* mark the property as dynamic */
402 of_property_set_flag(new, OF_DYNAMIC);
403
404 return new;
405
406 err_free:
407 kfree(new->name);
408 kfree(new->value);
409 kfree(new);
410 return NULL;
411}
412
413/**
414 * __of_node_dup() - Duplicate or create an empty device node dynamically.
415 * @np: if not NULL, contains properties to be duplicated in new node
416 * @full_name: string value to be duplicated into new node's full_name field
417 *
418 * Create a device tree node, optionally duplicating the properties of
419 * another node. The node data are dynamically allocated and all the node
420 * flags have the OF_DYNAMIC & OF_DETACHED bits set.
421 *
422 * Return: The newly allocated node or NULL on out of memory error.
423 */
424struct device_node *__of_node_dup(const struct device_node *np,
425 const char *full_name)
426{
427 struct device_node *node;
428
429 node = kzalloc(sizeof(*node), GFP_KERNEL);
430 if (!node)
431 return NULL;
432 node->full_name = kstrdup(full_name, GFP_KERNEL);
433 if (!node->full_name) {
434 kfree(node);
435 return NULL;
436 }
437
438 of_node_set_flag(node, OF_DYNAMIC);
439 of_node_set_flag(node, OF_DETACHED);
440 of_node_init(node);
441
442 /* Iterate over and duplicate all properties */
443 if (np) {
444 struct property *pp, *new_pp;
445 for_each_property_of_node(np, pp) {
446 new_pp = __of_prop_dup(pp, GFP_KERNEL);
447 if (!new_pp)
448 goto err_prop;
449 if (__of_add_property(node, new_pp)) {
450 kfree(new_pp->name);
451 kfree(new_pp->value);
452 kfree(new_pp);
453 goto err_prop;
454 }
455 }
456 }
457 return node;
458
459 err_prop:
460 of_node_put(node); /* Frees the node and properties */
461 return NULL;
462}
463
464static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
465{
466 if (ce->action == OF_RECONFIG_ATTACH_NODE &&
467 of_node_check_flag(ce->np, OF_OVERLAY)) {
468 if (kref_read(&ce->np->kobj.kref) > 1) {
469 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",
470 kref_read(&ce->np->kobj.kref), ce->np);
471 } else {
472 of_node_set_flag(ce->np, OF_OVERLAY_FREE_CSET);
473 }
474 }
475
476 of_node_put(ce->np);
477 list_del(&ce->node);
478 kfree(ce);
479}
480
481#ifdef DEBUG
482static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
483{
484 switch (ce->action) {
485 case OF_RECONFIG_ADD_PROPERTY:
486 case OF_RECONFIG_REMOVE_PROPERTY:
487 case OF_RECONFIG_UPDATE_PROPERTY:
488 pr_debug("cset<%p> %-15s %pOF/%s\n", ce, action_names[ce->action],
489 ce->np, ce->prop->name);
490 break;
491 case OF_RECONFIG_ATTACH_NODE:
492 case OF_RECONFIG_DETACH_NODE:
493 pr_debug("cset<%p> %-15s %pOF\n", ce, action_names[ce->action],
494 ce->np);
495 break;
496 }
497}
498#else
499static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
500{
501 /* empty */
502}
503#endif
504
505static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
506 struct of_changeset_entry *rce)
507{
508 memcpy(rce, ce, sizeof(*rce));
509
510 switch (ce->action) {
511 case OF_RECONFIG_ATTACH_NODE:
512 rce->action = OF_RECONFIG_DETACH_NODE;
513 break;
514 case OF_RECONFIG_DETACH_NODE:
515 rce->action = OF_RECONFIG_ATTACH_NODE;
516 break;
517 case OF_RECONFIG_ADD_PROPERTY:
518 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
519 break;
520 case OF_RECONFIG_REMOVE_PROPERTY:
521 rce->action = OF_RECONFIG_ADD_PROPERTY;
522 break;
523 case OF_RECONFIG_UPDATE_PROPERTY:
524 rce->old_prop = ce->prop;
525 rce->prop = ce->old_prop;
526 /* update was used but original property did not exist */
527 if (!rce->prop) {
528 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
529 rce->prop = ce->prop;
530 }
531 break;
532 }
533}
534
535static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
536 bool revert)
537{
538 struct of_reconfig_data rd;
539 struct of_changeset_entry ce_inverted;
540 int ret = 0;
541
542 if (revert) {
543 __of_changeset_entry_invert(ce, &ce_inverted);
544 ce = &ce_inverted;
545 }
546
547 switch (ce->action) {
548 case OF_RECONFIG_ATTACH_NODE:
549 case OF_RECONFIG_DETACH_NODE:
550 memset(&rd, 0, sizeof(rd));
551 rd.dn = ce->np;
552 ret = of_reconfig_notify(ce->action, &rd);
553 break;
554 case OF_RECONFIG_ADD_PROPERTY:
555 case OF_RECONFIG_REMOVE_PROPERTY:
556 case OF_RECONFIG_UPDATE_PROPERTY:
557 ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
558 break;
559 default:
560 pr_err("invalid devicetree changeset action: %i\n",
561 (int)ce->action);
562 ret = -EINVAL;
563 }
564
565 if (ret)
566 pr_err("changeset notifier error @%pOF\n", ce->np);
567 return ret;
568}
569
570static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
571{
572 struct property *old_prop, **propp;
573 unsigned long flags;
574 int ret = 0;
575
576 __of_changeset_entry_dump(ce);
577
578 raw_spin_lock_irqsave(&devtree_lock, flags);
579 switch (ce->action) {
580 case OF_RECONFIG_ATTACH_NODE:
581 __of_attach_node(ce->np);
582 break;
583 case OF_RECONFIG_DETACH_NODE:
584 __of_detach_node(ce->np);
585 break;
586 case OF_RECONFIG_ADD_PROPERTY:
587 /* If the property is in deadprops then it must be removed */
588 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
589 if (*propp == ce->prop) {
590 *propp = ce->prop->next;
591 ce->prop->next = NULL;
592 break;
593 }
594 }
595
596 ret = __of_add_property(ce->np, ce->prop);
597 if (ret) {
598 pr_err("changeset: add_property failed @%pOF/%s\n",
599 ce->np,
600 ce->prop->name);
601 break;
602 }
603 break;
604 case OF_RECONFIG_REMOVE_PROPERTY:
605 ret = __of_remove_property(ce->np, ce->prop);
606 if (ret) {
607 pr_err("changeset: remove_property failed @%pOF/%s\n",
608 ce->np,
609 ce->prop->name);
610 break;
611 }
612 break;
613
614 case OF_RECONFIG_UPDATE_PROPERTY:
615 /* If the property is in deadprops then it must be removed */
616 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
617 if (*propp == ce->prop) {
618 *propp = ce->prop->next;
619 ce->prop->next = NULL;
620 break;
621 }
622 }
623
624 ret = __of_update_property(ce->np, ce->prop, &old_prop);
625 if (ret) {
626 pr_err("changeset: update_property failed @%pOF/%s\n",
627 ce->np,
628 ce->prop->name);
629 break;
630 }
631 break;
632 default:
633 ret = -EINVAL;
634 }
635 raw_spin_unlock_irqrestore(&devtree_lock, flags);
636
637 if (ret)
638 return ret;
639
640 switch (ce->action) {
641 case OF_RECONFIG_ATTACH_NODE:
642 __of_attach_node_sysfs(ce->np);
643 break;
644 case OF_RECONFIG_DETACH_NODE:
645 __of_detach_node_sysfs(ce->np);
646 break;
647 case OF_RECONFIG_ADD_PROPERTY:
648 /* ignore duplicate names */
649 __of_add_property_sysfs(ce->np, ce->prop);
650 break;
651 case OF_RECONFIG_REMOVE_PROPERTY:
652 __of_remove_property_sysfs(ce->np, ce->prop);
653 break;
654 case OF_RECONFIG_UPDATE_PROPERTY:
655 __of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
656 break;
657 }
658
659 return 0;
660}
661
662static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
663{
664 struct of_changeset_entry ce_inverted;
665
666 __of_changeset_entry_invert(ce, &ce_inverted);
667 return __of_changeset_entry_apply(&ce_inverted);
668}
669
670/**
671 * of_changeset_init - Initialize a changeset for use
672 *
673 * @ocs: changeset pointer
674 *
675 * Initialize a changeset structure
676 */
677void of_changeset_init(struct of_changeset *ocs)
678{
679 memset(ocs, 0, sizeof(*ocs));
680 INIT_LIST_HEAD(&ocs->entries);
681}
682EXPORT_SYMBOL_GPL(of_changeset_init);
683
684/**
685 * of_changeset_destroy - Destroy a changeset
686 *
687 * @ocs: changeset pointer
688 *
689 * Destroys a changeset. Note that if a changeset is applied,
690 * its changes to the tree cannot be reverted.
691 */
692void of_changeset_destroy(struct of_changeset *ocs)
693{
694 struct of_changeset_entry *ce, *cen;
695
696 list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
697 __of_changeset_entry_destroy(ce);
698}
699EXPORT_SYMBOL_GPL(of_changeset_destroy);
700
701/*
702 * Apply the changeset entries in @ocs.
703 * If apply fails, an attempt is made to revert the entries that were
704 * successfully applied.
705 *
706 * If multiple revert errors occur then only the final revert error is reported.
707 *
708 * Returns 0 on success, a negative error value in case of an error.
709 * If a revert error occurs, it is returned in *ret_revert.
710 */
711int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
712{
713 struct of_changeset_entry *ce;
714 int ret, ret_tmp;
715
716 pr_debug("changeset: applying...\n");
717 list_for_each_entry(ce, &ocs->entries, node) {
718 ret = __of_changeset_entry_apply(ce);
719 if (ret) {
720 pr_err("Error applying changeset (%d)\n", ret);
721 list_for_each_entry_continue_reverse(ce, &ocs->entries,
722 node) {
723 ret_tmp = __of_changeset_entry_revert(ce);
724 if (ret_tmp)
725 *ret_revert = ret_tmp;
726 }
727 return ret;
728 }
729 }
730
731 return 0;
732}
733
734/*
735 * Returns 0 on success, a negative error value in case of an error.
736 *
737 * If multiple changeset entry notification errors occur then only the
738 * final notification error is reported.
739 */
740int __of_changeset_apply_notify(struct of_changeset *ocs)
741{
742 struct of_changeset_entry *ce;
743 int ret = 0, ret_tmp;
744
745 pr_debug("changeset: emitting notifiers.\n");
746
747 /* drop the global lock while emitting notifiers */
748 mutex_unlock(&of_mutex);
749 list_for_each_entry(ce, &ocs->entries, node) {
750 ret_tmp = __of_changeset_entry_notify(ce, 0);
751 if (ret_tmp)
752 ret = ret_tmp;
753 }
754 mutex_lock(&of_mutex);
755 pr_debug("changeset: notifiers sent.\n");
756
757 return ret;
758}
759
760/*
761 * Returns 0 on success, a negative error value in case of an error.
762 *
763 * If a changeset entry apply fails, an attempt is made to revert any
764 * previous entries in the changeset. If any of the reverts fails,
765 * that failure is not reported. Thus the state of the device tree
766 * is unknown if an apply error occurs.
767 */
768static int __of_changeset_apply(struct of_changeset *ocs)
769{
770 int ret, ret_revert = 0;
771
772 ret = __of_changeset_apply_entries(ocs, &ret_revert);
773 if (!ret)
774 ret = __of_changeset_apply_notify(ocs);
775
776 return ret;
777}
778
779/**
780 * of_changeset_apply - Applies a changeset
781 *
782 * @ocs: changeset pointer
783 *
784 * Applies a changeset to the live tree.
785 * Any side-effects of live tree state changes are applied here on
786 * success, like creation/destruction of devices and side-effects
787 * like creation of sysfs properties and directories.
788 *
789 * Return: 0 on success, a negative error value in case of an error.
790 * On error the partially applied effects are reverted.
791 */
792int of_changeset_apply(struct of_changeset *ocs)
793{
794 int ret;
795
796 mutex_lock(&of_mutex);
797 ret = __of_changeset_apply(ocs);
798 mutex_unlock(&of_mutex);
799
800 return ret;
801}
802EXPORT_SYMBOL_GPL(of_changeset_apply);
803
804/*
805 * Revert the changeset entries in @ocs.
806 * If revert fails, an attempt is made to re-apply the entries that were
807 * successfully removed.
808 *
809 * If multiple re-apply errors occur then only the final apply error is
810 * reported.
811 *
812 * Returns 0 on success, a negative error value in case of an error.
813 * If an apply error occurs, it is returned in *ret_apply.
814 */
815int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
816{
817 struct of_changeset_entry *ce;
818 int ret, ret_tmp;
819
820 pr_debug("changeset: reverting...\n");
821 list_for_each_entry_reverse(ce, &ocs->entries, node) {
822 ret = __of_changeset_entry_revert(ce);
823 if (ret) {
824 pr_err("Error reverting changeset (%d)\n", ret);
825 list_for_each_entry_continue(ce, &ocs->entries, node) {
826 ret_tmp = __of_changeset_entry_apply(ce);
827 if (ret_tmp)
828 *ret_apply = ret_tmp;
829 }
830 return ret;
831 }
832 }
833
834 return 0;
835}
836
837/*
838 * If multiple changeset entry notification errors occur then only the
839 * final notification error is reported.
840 */
841int __of_changeset_revert_notify(struct of_changeset *ocs)
842{
843 struct of_changeset_entry *ce;
844 int ret = 0, ret_tmp;
845
846 pr_debug("changeset: emitting notifiers.\n");
847
848 /* drop the global lock while emitting notifiers */
849 mutex_unlock(&of_mutex);
850 list_for_each_entry_reverse(ce, &ocs->entries, node) {
851 ret_tmp = __of_changeset_entry_notify(ce, 1);
852 if (ret_tmp)
853 ret = ret_tmp;
854 }
855 mutex_lock(&of_mutex);
856 pr_debug("changeset: notifiers sent.\n");
857
858 return ret;
859}
860
861static int __of_changeset_revert(struct of_changeset *ocs)
862{
863 int ret, ret_reply;
864
865 ret_reply = 0;
866 ret = __of_changeset_revert_entries(ocs, &ret_reply);
867
868 if (!ret)
869 ret = __of_changeset_revert_notify(ocs);
870
871 return ret;
872}
873
874/**
875 * of_changeset_revert - Reverts an applied changeset
876 *
877 * @ocs: changeset pointer
878 *
879 * Reverts a changeset returning the state of the tree to what it
880 * was before the application.
881 * Any side-effects like creation/destruction of devices and
882 * removal of sysfs properties and directories are applied.
883 *
884 * Return: 0 on success, a negative error value in case of an error.
885 */
886int of_changeset_revert(struct of_changeset *ocs)
887{
888 int ret;
889
890 mutex_lock(&of_mutex);
891 ret = __of_changeset_revert(ocs);
892 mutex_unlock(&of_mutex);
893
894 return ret;
895}
896EXPORT_SYMBOL_GPL(of_changeset_revert);
897
898/**
899 * of_changeset_action - Add an action to the tail of the changeset list
900 *
901 * @ocs: changeset pointer
902 * @action: action to perform
903 * @np: Pointer to device node
904 * @prop: Pointer to property
905 *
906 * On action being one of:
907 * + OF_RECONFIG_ATTACH_NODE
908 * + OF_RECONFIG_DETACH_NODE,
909 * + OF_RECONFIG_ADD_PROPERTY
910 * + OF_RECONFIG_REMOVE_PROPERTY,
911 * + OF_RECONFIG_UPDATE_PROPERTY
912 *
913 * Return: 0 on success, a negative error value in case of an error.
914 */
915int of_changeset_action(struct of_changeset *ocs, unsigned long action,
916 struct device_node *np, struct property *prop)
917{
918 struct of_changeset_entry *ce;
919
920 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
921 if (!ce)
922 return -ENOMEM;
923
924 /* get a reference to the node */
925 ce->action = action;
926 ce->np = of_node_get(np);
927 ce->prop = prop;
928
929 if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
930 ce->old_prop = of_find_property(np, prop->name, NULL);
931
932 /* add it to the list */
933 list_add_tail(&ce->node, &ocs->entries);
934 return 0;
935}
936EXPORT_SYMBOL_GPL(of_changeset_action);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Support for dynamic device trees.
4 *
5 * On some platforms, the device tree can be manipulated at runtime.
6 * The routines in this section support adding, removing and changing
7 * device tree nodes.
8 */
9
10#define pr_fmt(fmt) "OF: " fmt
11
12#include <linux/of.h>
13#include <linux/spinlock.h>
14#include <linux/slab.h>
15#include <linux/string.h>
16#include <linux/proc_fs.h>
17
18#include "of_private.h"
19
20static struct device_node *kobj_to_device_node(struct kobject *kobj)
21{
22 return container_of(kobj, struct device_node, kobj);
23}
24
25/**
26 * of_node_get() - Increment refcount of a node
27 * @node: Node to inc refcount, NULL is supported to simplify writing of
28 * callers
29 *
30 * Returns node.
31 */
32struct device_node *of_node_get(struct device_node *node)
33{
34 if (node)
35 kobject_get(&node->kobj);
36 return node;
37}
38EXPORT_SYMBOL(of_node_get);
39
40/**
41 * of_node_put() - Decrement refcount of a node
42 * @node: Node to dec refcount, NULL is supported to simplify writing of
43 * callers
44 */
45void of_node_put(struct device_node *node)
46{
47 if (node)
48 kobject_put(&node->kobj);
49}
50EXPORT_SYMBOL(of_node_put);
51
52static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
53
54int of_reconfig_notifier_register(struct notifier_block *nb)
55{
56 return blocking_notifier_chain_register(&of_reconfig_chain, nb);
57}
58EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
59
60int of_reconfig_notifier_unregister(struct notifier_block *nb)
61{
62 return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
63}
64EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
65
66#ifdef DEBUG
67const char *action_names[] = {
68 [OF_RECONFIG_ATTACH_NODE] = "ATTACH_NODE",
69 [OF_RECONFIG_DETACH_NODE] = "DETACH_NODE",
70 [OF_RECONFIG_ADD_PROPERTY] = "ADD_PROPERTY",
71 [OF_RECONFIG_REMOVE_PROPERTY] = "REMOVE_PROPERTY",
72 [OF_RECONFIG_UPDATE_PROPERTY] = "UPDATE_PROPERTY",
73};
74#endif
75
76int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
77{
78 int rc;
79#ifdef DEBUG
80 struct of_reconfig_data *pr = p;
81
82 switch (action) {
83 case OF_RECONFIG_ATTACH_NODE:
84 case OF_RECONFIG_DETACH_NODE:
85 pr_debug("notify %-15s %pOF\n", action_names[action],
86 pr->dn);
87 break;
88 case OF_RECONFIG_ADD_PROPERTY:
89 case OF_RECONFIG_REMOVE_PROPERTY:
90 case OF_RECONFIG_UPDATE_PROPERTY:
91 pr_debug("notify %-15s %pOF:%s\n", action_names[action],
92 pr->dn, pr->prop->name);
93 break;
94
95 }
96#endif
97 rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
98 return notifier_to_errno(rc);
99}
100
101/*
102 * of_reconfig_get_state_change() - Returns new state of device
103 * @action - action of the of notifier
104 * @arg - argument of the of notifier
105 *
106 * Returns the new state of a device based on the notifier used.
107 * Returns 0 on device going from enabled to disabled, 1 on device
108 * going from disabled to enabled and -1 on no change.
109 */
110int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr)
111{
112 struct property *prop, *old_prop = NULL;
113 int is_status, status_state, old_status_state, prev_state, new_state;
114
115 /* figure out if a device should be created or destroyed */
116 switch (action) {
117 case OF_RECONFIG_ATTACH_NODE:
118 case OF_RECONFIG_DETACH_NODE:
119 prop = of_find_property(pr->dn, "status", NULL);
120 break;
121 case OF_RECONFIG_ADD_PROPERTY:
122 case OF_RECONFIG_REMOVE_PROPERTY:
123 prop = pr->prop;
124 break;
125 case OF_RECONFIG_UPDATE_PROPERTY:
126 prop = pr->prop;
127 old_prop = pr->old_prop;
128 break;
129 default:
130 return OF_RECONFIG_NO_CHANGE;
131 }
132
133 is_status = 0;
134 status_state = -1;
135 old_status_state = -1;
136 prev_state = -1;
137 new_state = -1;
138
139 if (prop && !strcmp(prop->name, "status")) {
140 is_status = 1;
141 status_state = !strcmp(prop->value, "okay") ||
142 !strcmp(prop->value, "ok");
143 if (old_prop)
144 old_status_state = !strcmp(old_prop->value, "okay") ||
145 !strcmp(old_prop->value, "ok");
146 }
147
148 switch (action) {
149 case OF_RECONFIG_ATTACH_NODE:
150 prev_state = 0;
151 /* -1 & 0 status either missing or okay */
152 new_state = status_state != 0;
153 break;
154 case OF_RECONFIG_DETACH_NODE:
155 /* -1 & 0 status either missing or okay */
156 prev_state = status_state != 0;
157 new_state = 0;
158 break;
159 case OF_RECONFIG_ADD_PROPERTY:
160 if (is_status) {
161 /* no status property -> enabled (legacy) */
162 prev_state = 1;
163 new_state = status_state;
164 }
165 break;
166 case OF_RECONFIG_REMOVE_PROPERTY:
167 if (is_status) {
168 prev_state = status_state;
169 /* no status property -> enabled (legacy) */
170 new_state = 1;
171 }
172 break;
173 case OF_RECONFIG_UPDATE_PROPERTY:
174 if (is_status) {
175 prev_state = old_status_state != 0;
176 new_state = status_state != 0;
177 }
178 break;
179 }
180
181 if (prev_state == new_state)
182 return OF_RECONFIG_NO_CHANGE;
183
184 return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
185}
186EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
187
188int of_property_notify(int action, struct device_node *np,
189 struct property *prop, struct property *oldprop)
190{
191 struct of_reconfig_data pr;
192
193 /* only call notifiers if the node is attached */
194 if (!of_node_is_attached(np))
195 return 0;
196
197 pr.dn = np;
198 pr.prop = prop;
199 pr.old_prop = oldprop;
200 return of_reconfig_notify(action, &pr);
201}
202
203static void __of_attach_node(struct device_node *np)
204{
205 const __be32 *phandle;
206 int sz;
207
208 if (!of_node_check_flag(np, OF_OVERLAY)) {
209 np->name = __of_get_property(np, "name", NULL);
210 if (!np->name)
211 np->name = "<NULL>";
212
213 phandle = __of_get_property(np, "phandle", &sz);
214 if (!phandle)
215 phandle = __of_get_property(np, "linux,phandle", &sz);
216 if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
217 phandle = __of_get_property(np, "ibm,phandle", &sz);
218 if (phandle && (sz >= 4))
219 np->phandle = be32_to_cpup(phandle);
220 else
221 np->phandle = 0;
222 }
223
224 np->child = NULL;
225 np->sibling = np->parent->child;
226 np->parent->child = np;
227 of_node_clear_flag(np, OF_DETACHED);
228}
229
230/**
231 * of_attach_node() - Plug a device node into the tree and global list.
232 */
233int of_attach_node(struct device_node *np)
234{
235 struct of_reconfig_data rd;
236 unsigned long flags;
237
238 memset(&rd, 0, sizeof(rd));
239 rd.dn = np;
240
241 mutex_lock(&of_mutex);
242 raw_spin_lock_irqsave(&devtree_lock, flags);
243 __of_attach_node(np);
244 raw_spin_unlock_irqrestore(&devtree_lock, flags);
245
246 __of_attach_node_sysfs(np);
247 mutex_unlock(&of_mutex);
248
249 of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);
250
251 return 0;
252}
253
254void __of_detach_node(struct device_node *np)
255{
256 struct device_node *parent;
257
258 if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
259 return;
260
261 parent = np->parent;
262 if (WARN_ON(!parent))
263 return;
264
265 if (parent->child == np)
266 parent->child = np->sibling;
267 else {
268 struct device_node *prevsib;
269 for (prevsib = np->parent->child;
270 prevsib->sibling != np;
271 prevsib = prevsib->sibling)
272 ;
273 prevsib->sibling = np->sibling;
274 }
275
276 of_node_set_flag(np, OF_DETACHED);
277
278 /* race with of_find_node_by_phandle() prevented by devtree_lock */
279 __of_phandle_cache_inv_entry(np->phandle);
280}
281
282/**
283 * of_detach_node() - "Unplug" a node from the device tree.
284 */
285int of_detach_node(struct device_node *np)
286{
287 struct of_reconfig_data rd;
288 unsigned long flags;
289
290 memset(&rd, 0, sizeof(rd));
291 rd.dn = np;
292
293 mutex_lock(&of_mutex);
294 raw_spin_lock_irqsave(&devtree_lock, flags);
295 __of_detach_node(np);
296 raw_spin_unlock_irqrestore(&devtree_lock, flags);
297
298 __of_detach_node_sysfs(np);
299 mutex_unlock(&of_mutex);
300
301 of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
302
303 return 0;
304}
305EXPORT_SYMBOL_GPL(of_detach_node);
306
307static void property_list_free(struct property *prop_list)
308{
309 struct property *prop, *next;
310
311 for (prop = prop_list; prop != NULL; prop = next) {
312 next = prop->next;
313 kfree(prop->name);
314 kfree(prop->value);
315 kfree(prop);
316 }
317}
318
319/**
320 * of_node_release() - release a dynamically allocated node
321 * @kref: kref element of the node to be released
322 *
323 * In of_node_put() this function is passed to kref_put() as the destructor.
324 */
325void of_node_release(struct kobject *kobj)
326{
327 struct device_node *node = kobj_to_device_node(kobj);
328
329 /* We should never be releasing nodes that haven't been detached. */
330 if (!of_node_check_flag(node, OF_DETACHED)) {
331 pr_err("ERROR: Bad of_node_put() on %pOF\n", node);
332 dump_stack();
333 return;
334 }
335 if (!of_node_check_flag(node, OF_DYNAMIC))
336 return;
337
338 if (of_node_check_flag(node, OF_OVERLAY)) {
339
340 if (!of_node_check_flag(node, OF_OVERLAY_FREE_CSET)) {
341 /* premature refcount of zero, do not free memory */
342 pr_err("ERROR: memory leak before free overlay changeset, %pOF\n",
343 node);
344 return;
345 }
346
347 /*
348 * If node->properties non-empty then properties were added
349 * to this node either by different overlay that has not
350 * yet been removed, or by a non-overlay mechanism.
351 */
352 if (node->properties)
353 pr_err("ERROR: %s(), unexpected properties in %pOF\n",
354 __func__, node);
355 }
356
357 property_list_free(node->properties);
358 property_list_free(node->deadprops);
359
360 kfree(node->full_name);
361 kfree(node->data);
362 kfree(node);
363}
364
365/**
366 * __of_prop_dup - Copy a property dynamically.
367 * @prop: Property to copy
368 * @allocflags: Allocation flags (typically pass GFP_KERNEL)
369 *
370 * Copy a property by dynamically allocating the memory of both the
371 * property structure and the property name & contents. The property's
372 * flags have the OF_DYNAMIC bit set so that we can differentiate between
373 * dynamically allocated properties and not.
374 * Returns the newly allocated property or NULL on out of memory error.
375 */
376struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
377{
378 struct property *new;
379
380 new = kzalloc(sizeof(*new), allocflags);
381 if (!new)
382 return NULL;
383
384 /*
385 * NOTE: There is no check for zero length value.
386 * In case of a boolean property, this will allocate a value
387 * of zero bytes. We do this to work around the use
388 * of of_get_property() calls on boolean values.
389 */
390 new->name = kstrdup(prop->name, allocflags);
391 new->value = kmemdup(prop->value, prop->length, allocflags);
392 new->length = prop->length;
393 if (!new->name || !new->value)
394 goto err_free;
395
396 /* mark the property as dynamic */
397 of_property_set_flag(new, OF_DYNAMIC);
398
399 return new;
400
401 err_free:
402 kfree(new->name);
403 kfree(new->value);
404 kfree(new);
405 return NULL;
406}
407
408/**
409 * __of_node_dup() - Duplicate or create an empty device node dynamically.
410 * @np: if not NULL, contains properties to be duplicated in new node
411 * @full_name: string value to be duplicated into new node's full_name field
412 *
413 * Create a device tree node, optionally duplicating the properties of
414 * another node. The node data are dynamically allocated and all the node
415 * flags have the OF_DYNAMIC & OF_DETACHED bits set.
416 *
417 * Returns the newly allocated node or NULL on out of memory error.
418 */
419struct device_node *__of_node_dup(const struct device_node *np,
420 const char *full_name)
421{
422 struct device_node *node;
423
424 node = kzalloc(sizeof(*node), GFP_KERNEL);
425 if (!node)
426 return NULL;
427 node->full_name = kstrdup(full_name, GFP_KERNEL);
428 if (!node->full_name) {
429 kfree(node);
430 return NULL;
431 }
432
433 of_node_set_flag(node, OF_DYNAMIC);
434 of_node_set_flag(node, OF_DETACHED);
435 of_node_init(node);
436
437 /* Iterate over and duplicate all properties */
438 if (np) {
439 struct property *pp, *new_pp;
440 for_each_property_of_node(np, pp) {
441 new_pp = __of_prop_dup(pp, GFP_KERNEL);
442 if (!new_pp)
443 goto err_prop;
444 if (__of_add_property(node, new_pp)) {
445 kfree(new_pp->name);
446 kfree(new_pp->value);
447 kfree(new_pp);
448 goto err_prop;
449 }
450 }
451 }
452 return node;
453
454 err_prop:
455 of_node_put(node); /* Frees the node and properties */
456 return NULL;
457}
458
459static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
460{
461 if (ce->action == OF_RECONFIG_ATTACH_NODE &&
462 of_node_check_flag(ce->np, OF_OVERLAY)) {
463 if (kref_read(&ce->np->kobj.kref) > 1) {
464 pr_err("ERROR: memory leak, expected refcount 1 instead of %d, of_node_get()/of_node_put() unbalanced - destroy cset entry: attach overlay node %pOF\n",
465 kref_read(&ce->np->kobj.kref), ce->np);
466 } else {
467 of_node_set_flag(ce->np, OF_OVERLAY_FREE_CSET);
468 }
469 }
470
471 of_node_put(ce->np);
472 list_del(&ce->node);
473 kfree(ce);
474}
475
476#ifdef DEBUG
477static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
478{
479 switch (ce->action) {
480 case OF_RECONFIG_ADD_PROPERTY:
481 case OF_RECONFIG_REMOVE_PROPERTY:
482 case OF_RECONFIG_UPDATE_PROPERTY:
483 pr_debug("cset<%p> %-15s %pOF/%s\n", ce, action_names[ce->action],
484 ce->np, ce->prop->name);
485 break;
486 case OF_RECONFIG_ATTACH_NODE:
487 case OF_RECONFIG_DETACH_NODE:
488 pr_debug("cset<%p> %-15s %pOF\n", ce, action_names[ce->action],
489 ce->np);
490 break;
491 }
492}
493#else
494static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
495{
496 /* empty */
497}
498#endif
499
500static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
501 struct of_changeset_entry *rce)
502{
503 memcpy(rce, ce, sizeof(*rce));
504
505 switch (ce->action) {
506 case OF_RECONFIG_ATTACH_NODE:
507 rce->action = OF_RECONFIG_DETACH_NODE;
508 break;
509 case OF_RECONFIG_DETACH_NODE:
510 rce->action = OF_RECONFIG_ATTACH_NODE;
511 break;
512 case OF_RECONFIG_ADD_PROPERTY:
513 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
514 break;
515 case OF_RECONFIG_REMOVE_PROPERTY:
516 rce->action = OF_RECONFIG_ADD_PROPERTY;
517 break;
518 case OF_RECONFIG_UPDATE_PROPERTY:
519 rce->old_prop = ce->prop;
520 rce->prop = ce->old_prop;
521 /* update was used but original property did not exist */
522 if (!rce->prop) {
523 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
524 rce->prop = ce->prop;
525 }
526 break;
527 }
528}
529
530static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
531 bool revert)
532{
533 struct of_reconfig_data rd;
534 struct of_changeset_entry ce_inverted;
535 int ret = 0;
536
537 if (revert) {
538 __of_changeset_entry_invert(ce, &ce_inverted);
539 ce = &ce_inverted;
540 }
541
542 switch (ce->action) {
543 case OF_RECONFIG_ATTACH_NODE:
544 case OF_RECONFIG_DETACH_NODE:
545 memset(&rd, 0, sizeof(rd));
546 rd.dn = ce->np;
547 ret = of_reconfig_notify(ce->action, &rd);
548 break;
549 case OF_RECONFIG_ADD_PROPERTY:
550 case OF_RECONFIG_REMOVE_PROPERTY:
551 case OF_RECONFIG_UPDATE_PROPERTY:
552 ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
553 break;
554 default:
555 pr_err("invalid devicetree changeset action: %i\n",
556 (int)ce->action);
557 ret = -EINVAL;
558 }
559
560 if (ret)
561 pr_err("changeset notifier error @%pOF\n", ce->np);
562 return ret;
563}
564
565static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
566{
567 struct property *old_prop, **propp;
568 unsigned long flags;
569 int ret = 0;
570
571 __of_changeset_entry_dump(ce);
572
573 raw_spin_lock_irqsave(&devtree_lock, flags);
574 switch (ce->action) {
575 case OF_RECONFIG_ATTACH_NODE:
576 __of_attach_node(ce->np);
577 break;
578 case OF_RECONFIG_DETACH_NODE:
579 __of_detach_node(ce->np);
580 break;
581 case OF_RECONFIG_ADD_PROPERTY:
582 /* If the property is in deadprops then it must be removed */
583 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
584 if (*propp == ce->prop) {
585 *propp = ce->prop->next;
586 ce->prop->next = NULL;
587 break;
588 }
589 }
590
591 ret = __of_add_property(ce->np, ce->prop);
592 if (ret) {
593 pr_err("changeset: add_property failed @%pOF/%s\n",
594 ce->np,
595 ce->prop->name);
596 break;
597 }
598 break;
599 case OF_RECONFIG_REMOVE_PROPERTY:
600 ret = __of_remove_property(ce->np, ce->prop);
601 if (ret) {
602 pr_err("changeset: remove_property failed @%pOF/%s\n",
603 ce->np,
604 ce->prop->name);
605 break;
606 }
607 break;
608
609 case OF_RECONFIG_UPDATE_PROPERTY:
610 /* If the property is in deadprops then it must be removed */
611 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
612 if (*propp == ce->prop) {
613 *propp = ce->prop->next;
614 ce->prop->next = NULL;
615 break;
616 }
617 }
618
619 ret = __of_update_property(ce->np, ce->prop, &old_prop);
620 if (ret) {
621 pr_err("changeset: update_property failed @%pOF/%s\n",
622 ce->np,
623 ce->prop->name);
624 break;
625 }
626 break;
627 default:
628 ret = -EINVAL;
629 }
630 raw_spin_unlock_irqrestore(&devtree_lock, flags);
631
632 if (ret)
633 return ret;
634
635 switch (ce->action) {
636 case OF_RECONFIG_ATTACH_NODE:
637 __of_attach_node_sysfs(ce->np);
638 break;
639 case OF_RECONFIG_DETACH_NODE:
640 __of_detach_node_sysfs(ce->np);
641 break;
642 case OF_RECONFIG_ADD_PROPERTY:
643 /* ignore duplicate names */
644 __of_add_property_sysfs(ce->np, ce->prop);
645 break;
646 case OF_RECONFIG_REMOVE_PROPERTY:
647 __of_remove_property_sysfs(ce->np, ce->prop);
648 break;
649 case OF_RECONFIG_UPDATE_PROPERTY:
650 __of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
651 break;
652 }
653
654 return 0;
655}
656
657static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
658{
659 struct of_changeset_entry ce_inverted;
660
661 __of_changeset_entry_invert(ce, &ce_inverted);
662 return __of_changeset_entry_apply(&ce_inverted);
663}
664
665/**
666 * of_changeset_init - Initialize a changeset for use
667 *
668 * @ocs: changeset pointer
669 *
670 * Initialize a changeset structure
671 */
672void of_changeset_init(struct of_changeset *ocs)
673{
674 memset(ocs, 0, sizeof(*ocs));
675 INIT_LIST_HEAD(&ocs->entries);
676}
677EXPORT_SYMBOL_GPL(of_changeset_init);
678
679/**
680 * of_changeset_destroy - Destroy a changeset
681 *
682 * @ocs: changeset pointer
683 *
684 * Destroys a changeset. Note that if a changeset is applied,
685 * its changes to the tree cannot be reverted.
686 */
687void of_changeset_destroy(struct of_changeset *ocs)
688{
689 struct of_changeset_entry *ce, *cen;
690
691 list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
692 __of_changeset_entry_destroy(ce);
693}
694EXPORT_SYMBOL_GPL(of_changeset_destroy);
695
696/*
697 * Apply the changeset entries in @ocs.
698 * If apply fails, an attempt is made to revert the entries that were
699 * successfully applied.
700 *
701 * If multiple revert errors occur then only the final revert error is reported.
702 *
703 * Returns 0 on success, a negative error value in case of an error.
704 * If a revert error occurs, it is returned in *ret_revert.
705 */
706int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
707{
708 struct of_changeset_entry *ce;
709 int ret, ret_tmp;
710
711 pr_debug("changeset: applying...\n");
712 list_for_each_entry(ce, &ocs->entries, node) {
713 ret = __of_changeset_entry_apply(ce);
714 if (ret) {
715 pr_err("Error applying changeset (%d)\n", ret);
716 list_for_each_entry_continue_reverse(ce, &ocs->entries,
717 node) {
718 ret_tmp = __of_changeset_entry_revert(ce);
719 if (ret_tmp)
720 *ret_revert = ret_tmp;
721 }
722 return ret;
723 }
724 }
725
726 return 0;
727}
728
729/*
730 * Returns 0 on success, a negative error value in case of an error.
731 *
732 * If multiple changeset entry notification errors occur then only the
733 * final notification error is reported.
734 */
735int __of_changeset_apply_notify(struct of_changeset *ocs)
736{
737 struct of_changeset_entry *ce;
738 int ret = 0, ret_tmp;
739
740 pr_debug("changeset: emitting notifiers.\n");
741
742 /* drop the global lock while emitting notifiers */
743 mutex_unlock(&of_mutex);
744 list_for_each_entry(ce, &ocs->entries, node) {
745 ret_tmp = __of_changeset_entry_notify(ce, 0);
746 if (ret_tmp)
747 ret = ret_tmp;
748 }
749 mutex_lock(&of_mutex);
750 pr_debug("changeset: notifiers sent.\n");
751
752 return ret;
753}
754
755/*
756 * Returns 0 on success, a negative error value in case of an error.
757 *
758 * If a changeset entry apply fails, an attempt is made to revert any
759 * previous entries in the changeset. If any of the reverts fails,
760 * that failure is not reported. Thus the state of the device tree
761 * is unknown if an apply error occurs.
762 */
763static int __of_changeset_apply(struct of_changeset *ocs)
764{
765 int ret, ret_revert = 0;
766
767 ret = __of_changeset_apply_entries(ocs, &ret_revert);
768 if (!ret)
769 ret = __of_changeset_apply_notify(ocs);
770
771 return ret;
772}
773
774/**
775 * of_changeset_apply - Applies a changeset
776 *
777 * @ocs: changeset pointer
778 *
779 * Applies a changeset to the live tree.
780 * Any side-effects of live tree state changes are applied here on
781 * success, like creation/destruction of devices and side-effects
782 * like creation of sysfs properties and directories.
783 * Returns 0 on success, a negative error value in case of an error.
784 * On error the partially applied effects are reverted.
785 */
786int of_changeset_apply(struct of_changeset *ocs)
787{
788 int ret;
789
790 mutex_lock(&of_mutex);
791 ret = __of_changeset_apply(ocs);
792 mutex_unlock(&of_mutex);
793
794 return ret;
795}
796EXPORT_SYMBOL_GPL(of_changeset_apply);
797
798/*
799 * Revert the changeset entries in @ocs.
800 * If revert fails, an attempt is made to re-apply the entries that were
801 * successfully removed.
802 *
803 * If multiple re-apply errors occur then only the final apply error is
804 * reported.
805 *
806 * Returns 0 on success, a negative error value in case of an error.
807 * If an apply error occurs, it is returned in *ret_apply.
808 */
809int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
810{
811 struct of_changeset_entry *ce;
812 int ret, ret_tmp;
813
814 pr_debug("changeset: reverting...\n");
815 list_for_each_entry_reverse(ce, &ocs->entries, node) {
816 ret = __of_changeset_entry_revert(ce);
817 if (ret) {
818 pr_err("Error reverting changeset (%d)\n", ret);
819 list_for_each_entry_continue(ce, &ocs->entries, node) {
820 ret_tmp = __of_changeset_entry_apply(ce);
821 if (ret_tmp)
822 *ret_apply = ret_tmp;
823 }
824 return ret;
825 }
826 }
827
828 return 0;
829}
830
831/*
832 * If multiple changeset entry notification errors occur then only the
833 * final notification error is reported.
834 */
835int __of_changeset_revert_notify(struct of_changeset *ocs)
836{
837 struct of_changeset_entry *ce;
838 int ret = 0, ret_tmp;
839
840 pr_debug("changeset: emitting notifiers.\n");
841
842 /* drop the global lock while emitting notifiers */
843 mutex_unlock(&of_mutex);
844 list_for_each_entry_reverse(ce, &ocs->entries, node) {
845 ret_tmp = __of_changeset_entry_notify(ce, 1);
846 if (ret_tmp)
847 ret = ret_tmp;
848 }
849 mutex_lock(&of_mutex);
850 pr_debug("changeset: notifiers sent.\n");
851
852 return ret;
853}
854
855static int __of_changeset_revert(struct of_changeset *ocs)
856{
857 int ret, ret_reply;
858
859 ret_reply = 0;
860 ret = __of_changeset_revert_entries(ocs, &ret_reply);
861
862 if (!ret)
863 ret = __of_changeset_revert_notify(ocs);
864
865 return ret;
866}
867
868/**
869 * of_changeset_revert - Reverts an applied changeset
870 *
871 * @ocs: changeset pointer
872 *
873 * Reverts a changeset returning the state of the tree to what it
874 * was before the application.
875 * Any side-effects like creation/destruction of devices and
876 * removal of sysfs properties and directories are applied.
877 * Returns 0 on success, a negative error value in case of an error.
878 */
879int of_changeset_revert(struct of_changeset *ocs)
880{
881 int ret;
882
883 mutex_lock(&of_mutex);
884 ret = __of_changeset_revert(ocs);
885 mutex_unlock(&of_mutex);
886
887 return ret;
888}
889EXPORT_SYMBOL_GPL(of_changeset_revert);
890
891/**
892 * of_changeset_action - Add an action to the tail of the changeset list
893 *
894 * @ocs: changeset pointer
895 * @action: action to perform
896 * @np: Pointer to device node
897 * @prop: Pointer to property
898 *
899 * On action being one of:
900 * + OF_RECONFIG_ATTACH_NODE
901 * + OF_RECONFIG_DETACH_NODE,
902 * + OF_RECONFIG_ADD_PROPERTY
903 * + OF_RECONFIG_REMOVE_PROPERTY,
904 * + OF_RECONFIG_UPDATE_PROPERTY
905 * Returns 0 on success, a negative error value in case of an error.
906 */
907int of_changeset_action(struct of_changeset *ocs, unsigned long action,
908 struct device_node *np, struct property *prop)
909{
910 struct of_changeset_entry *ce;
911
912 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
913 if (!ce)
914 return -ENOMEM;
915
916 /* get a reference to the node */
917 ce->action = action;
918 ce->np = of_node_get(np);
919 ce->prop = prop;
920
921 if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
922 ce->old_prop = of_find_property(np, prop->name, NULL);
923
924 /* add it to the list */
925 list_add_tail(&ce->node, &ocs->entries);
926 return 0;
927}
928EXPORT_SYMBOL_GPL(of_changeset_action);