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(kobj: &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(kobj: &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(nh: &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(nh: &of_reconfig_chain, nb);
63}
64EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
65
66static const char *action_names[] = {
67 [0] = "INVALID",
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
75#define _do_print(func, prefix, action, node, prop, ...) ({ \
76 func("changeset: " prefix "%-15s %pOF%s%s\n", \
77 ##__VA_ARGS__, action_names[action], node, \
78 prop ? ":" : "", prop ? prop->name : ""); \
79})
80#define of_changeset_action_err(...) _do_print(pr_err, __VA_ARGS__)
81#define of_changeset_action_debug(...) _do_print(pr_debug, __VA_ARGS__)
82
83int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
84{
85 int rc;
86 struct of_reconfig_data *pr = p;
87
88 of_changeset_action_debug("notify: ", action, pr->dn, pr->prop);
89
90 rc = blocking_notifier_call_chain(nh: &of_reconfig_chain, val: action, v: p);
91 return notifier_to_errno(ret: rc);
92}
93
94/*
95 * of_reconfig_get_state_change() - Returns new state of device
96 * @action - action of the of notifier
97 * @arg - argument of the of notifier
98 *
99 * Returns the new state of a device based on the notifier used.
100 *
101 * Return: 0 on device going from enabled to disabled, 1 on device
102 * going from disabled to enabled and -1 on no change.
103 */
104int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr)
105{
106 struct property *prop, *old_prop = NULL;
107 int is_status, status_state, old_status_state, prev_state, new_state;
108
109 /* figure out if a device should be created or destroyed */
110 switch (action) {
111 case OF_RECONFIG_ATTACH_NODE:
112 case OF_RECONFIG_DETACH_NODE:
113 prop = of_find_property(np: pr->dn, name: "status", NULL);
114 break;
115 case OF_RECONFIG_ADD_PROPERTY:
116 case OF_RECONFIG_REMOVE_PROPERTY:
117 prop = pr->prop;
118 break;
119 case OF_RECONFIG_UPDATE_PROPERTY:
120 prop = pr->prop;
121 old_prop = pr->old_prop;
122 break;
123 default:
124 return OF_RECONFIG_NO_CHANGE;
125 }
126
127 is_status = 0;
128 status_state = -1;
129 old_status_state = -1;
130 prev_state = -1;
131 new_state = -1;
132
133 if (prop && !strcmp(prop->name, "status")) {
134 is_status = 1;
135 status_state = !strcmp(prop->value, "okay") ||
136 !strcmp(prop->value, "ok");
137 if (old_prop)
138 old_status_state = !strcmp(old_prop->value, "okay") ||
139 !strcmp(old_prop->value, "ok");
140 }
141
142 switch (action) {
143 case OF_RECONFIG_ATTACH_NODE:
144 prev_state = 0;
145 /* -1 & 0 status either missing or okay */
146 new_state = status_state != 0;
147 break;
148 case OF_RECONFIG_DETACH_NODE:
149 /* -1 & 0 status either missing or okay */
150 prev_state = status_state != 0;
151 new_state = 0;
152 break;
153 case OF_RECONFIG_ADD_PROPERTY:
154 if (is_status) {
155 /* no status property -> enabled (legacy) */
156 prev_state = 1;
157 new_state = status_state;
158 }
159 break;
160 case OF_RECONFIG_REMOVE_PROPERTY:
161 if (is_status) {
162 prev_state = status_state;
163 /* no status property -> enabled (legacy) */
164 new_state = 1;
165 }
166 break;
167 case OF_RECONFIG_UPDATE_PROPERTY:
168 if (is_status) {
169 prev_state = old_status_state != 0;
170 new_state = status_state != 0;
171 }
172 break;
173 }
174
175 if (prev_state == new_state)
176 return OF_RECONFIG_NO_CHANGE;
177
178 return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
179}
180EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
181
182int of_property_notify(int action, struct device_node *np,
183 struct property *prop, struct property *oldprop)
184{
185 struct of_reconfig_data pr;
186
187 /* only call notifiers if the node is attached */
188 if (!of_node_is_attached(node: np))
189 return 0;
190
191 pr.dn = np;
192 pr.prop = prop;
193 pr.old_prop = oldprop;
194 return of_reconfig_notify(action, p: &pr);
195}
196
197static void __of_attach_node(struct device_node *np)
198{
199 const __be32 *phandle;
200 int sz;
201 unsigned long flags;
202
203 raw_spin_lock_irqsave(&devtree_lock, flags);
204
205 if (!of_node_check_flag(n: np, OF_OVERLAY)) {
206 np->name = __of_get_property(np, name: "name", NULL);
207 if (!np->name)
208 np->name = "<NULL>";
209
210 phandle = __of_get_property(np, name: "phandle", lenp: &sz);
211 if (!phandle)
212 phandle = __of_get_property(np, name: "linux,phandle", lenp: &sz);
213 if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
214 phandle = __of_get_property(np, name: "ibm,phandle", lenp: &sz);
215 if (phandle && (sz >= 4))
216 np->phandle = be32_to_cpup(p: phandle);
217 else
218 np->phandle = 0;
219 }
220
221 np->child = NULL;
222 np->sibling = np->parent->child;
223 np->parent->child = np;
224 of_node_clear_flag(n: np, OF_DETACHED);
225 np->fwnode.flags |= FWNODE_FLAG_NOT_DEVICE;
226
227 raw_spin_unlock_irqrestore(&devtree_lock, flags);
228
229 __of_attach_node_sysfs(np);
230}
231
232/**
233 * of_attach_node() - Plug a device node into the tree and global list.
234 * @np: Pointer to the caller's Device Node
235 */
236int of_attach_node(struct device_node *np)
237{
238 struct of_reconfig_data rd;
239
240 memset(&rd, 0, sizeof(rd));
241 rd.dn = np;
242
243 mutex_lock(&of_mutex);
244 __of_attach_node(np);
245 mutex_unlock(lock: &of_mutex);
246
247 of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, p: &rd);
248
249 return 0;
250}
251
252void __of_detach_node(struct device_node *np)
253{
254 struct device_node *parent;
255 unsigned long flags;
256
257 raw_spin_lock_irqsave(&devtree_lock, flags);
258
259 parent = np->parent;
260 if (WARN_ON(of_node_check_flag(np, OF_DETACHED) || !parent)) {
261 raw_spin_unlock_irqrestore(&devtree_lock, flags);
262 return;
263 }
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(n: np, OF_DETACHED);
277
278 /* race with of_find_node_by_phandle() prevented by devtree_lock */
279 __of_phandle_cache_inv_entry(handle: np->phandle);
280
281 raw_spin_unlock_irqrestore(&devtree_lock, flags);
282
283 __of_detach_node_sysfs(np);
284}
285
286/**
287 * of_detach_node() - "Unplug" a node from the device tree.
288 * @np: Pointer to the caller's Device Node
289 */
290int of_detach_node(struct device_node *np)
291{
292 struct of_reconfig_data rd;
293
294 memset(&rd, 0, sizeof(rd));
295 rd.dn = np;
296
297 mutex_lock(&of_mutex);
298 __of_detach_node(np);
299 mutex_unlock(lock: &of_mutex);
300
301 of_reconfig_notify(OF_RECONFIG_DETACH_NODE, p: &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(objp: prop->name);
314 kfree(objp: prop->value);
315 kfree(objp: prop);
316 }
317}
318
319/**
320 * of_node_release() - release a dynamically allocated node
321 * @kobj: kernel object 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 /*
330 * can not use '"%pOF", node' in pr_err() calls from this function
331 * because an of_node_get(node) when refcount is already zero
332 * will result in an error and a stack dump
333 */
334
335 /* We should never be releasing nodes that haven't been detached. */
336 if (!of_node_check_flag(n: node, OF_DETACHED)) {
337
338 pr_err("ERROR: %s() detected bad of_node_put() on %pOF/%s\n",
339 __func__, node->parent, node->full_name);
340
341 /*
342 * of unittests will test this path. Do not print the stack
343 * trace when the error is caused by unittest so that we do
344 * not display what a normal developer might reasonably
345 * consider a real bug.
346 */
347 if (!IS_ENABLED(CONFIG_OF_UNITTEST) ||
348 strcmp(node->parent->full_name, "testcase-data")) {
349 dump_stack();
350 pr_err("ERROR: next of_node_put() on this node will result in a kobject warning 'refcount_t: underflow; use-after-free.'\n");
351 }
352
353 return;
354 }
355 if (!of_node_check_flag(n: node, OF_DYNAMIC))
356 return;
357
358 if (of_node_check_flag(n: node, OF_OVERLAY)) {
359
360 if (!of_node_check_flag(n: node, OF_OVERLAY_FREE_CSET)) {
361 /* premature refcount of zero, do not free memory */
362 pr_err("ERROR: memory leak before free overlay changeset, %pOF\n",
363 node);
364 return;
365 }
366
367 /*
368 * If node->properties non-empty then properties were added
369 * to this node either by different overlay that has not
370 * yet been removed, or by a non-overlay mechanism.
371 */
372 if (node->properties)
373 pr_err("ERROR: %s(), unexpected properties in %pOF\n",
374 __func__, node);
375 }
376
377 if (node->child)
378 pr_err("ERROR: %s() unexpected children for %pOF/%s\n",
379 __func__, node->parent, node->full_name);
380
381 property_list_free(prop_list: node->properties);
382 property_list_free(prop_list: node->deadprops);
383 fwnode_links_purge(of_fwnode_handle(node));
384
385 kfree(objp: node->full_name);
386 kfree(objp: node->data);
387 kfree(objp: node);
388}
389
390/**
391 * __of_prop_dup - Copy a property dynamically.
392 * @prop: Property to copy
393 * @allocflags: Allocation flags (typically pass GFP_KERNEL)
394 *
395 * Copy a property by dynamically allocating the memory of both the
396 * property structure and the property name & contents. The property's
397 * flags have the OF_DYNAMIC bit set so that we can differentiate between
398 * dynamically allocated properties and not.
399 *
400 * Return: The newly allocated property or NULL on out of memory error.
401 */
402struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
403{
404 struct property *new;
405
406 new = kzalloc(size: sizeof(*new), flags: allocflags);
407 if (!new)
408 return NULL;
409
410 /*
411 * NOTE: There is no check for zero length value.
412 * In case of a boolean property, this will allocate a value
413 * of zero bytes. We do this to work around the use
414 * of of_get_property() calls on boolean values.
415 */
416 new->name = kstrdup(s: prop->name, gfp: allocflags);
417 new->value = kmemdup(p: prop->value, size: prop->length, gfp: allocflags);
418 new->length = prop->length;
419 if (!new->name || !new->value)
420 goto err_free;
421
422 /* mark the property as dynamic */
423 of_property_set_flag(p: new, OF_DYNAMIC);
424
425 return new;
426
427 err_free:
428 kfree(objp: new->name);
429 kfree(objp: new->value);
430 kfree(objp: new);
431 return NULL;
432}
433
434/**
435 * __of_node_dup() - Duplicate or create an empty device node dynamically.
436 * @np: if not NULL, contains properties to be duplicated in new node
437 * @full_name: string value to be duplicated into new node's full_name field
438 *
439 * Create a device tree node, optionally duplicating the properties of
440 * another node. The node data are dynamically allocated and all the node
441 * flags have the OF_DYNAMIC & OF_DETACHED bits set.
442 *
443 * Return: The newly allocated node or NULL on out of memory error. Use
444 * of_node_put() on it when done to free the memory allocated for it.
445 */
446struct device_node *__of_node_dup(const struct device_node *np,
447 const char *full_name)
448{
449 struct device_node *node;
450
451 node = kzalloc(size: sizeof(*node), GFP_KERNEL);
452 if (!node)
453 return NULL;
454 node->full_name = kstrdup(s: full_name, GFP_KERNEL);
455 if (!node->full_name) {
456 kfree(objp: node);
457 return NULL;
458 }
459
460 of_node_set_flag(n: node, OF_DYNAMIC);
461 of_node_set_flag(n: node, OF_DETACHED);
462 of_node_init(node);
463
464 /* Iterate over and duplicate all properties */
465 if (np) {
466 struct property *pp, *new_pp;
467 for_each_property_of_node(np, pp) {
468 new_pp = __of_prop_dup(prop: pp, GFP_KERNEL);
469 if (!new_pp)
470 goto err_prop;
471 if (__of_add_property(np: node, prop: new_pp)) {
472 kfree(objp: new_pp->name);
473 kfree(objp: new_pp->value);
474 kfree(objp: new_pp);
475 goto err_prop;
476 }
477 }
478 }
479 return node;
480
481 err_prop:
482 of_node_put(node); /* Frees the node and properties */
483 return NULL;
484}
485
486/**
487 * of_changeset_create_node - Dynamically create a device node and attach to
488 * a given changeset.
489 *
490 * @ocs: Pointer to changeset
491 * @parent: Pointer to parent device node
492 * @full_name: Node full name
493 *
494 * Return: Pointer to the created device node or NULL in case of an error.
495 */
496struct device_node *of_changeset_create_node(struct of_changeset *ocs,
497 struct device_node *parent,
498 const char *full_name)
499{
500 struct device_node *np;
501 int ret;
502
503 np = __of_node_dup(NULL, full_name);
504 if (!np)
505 return NULL;
506 np->parent = parent;
507
508 ret = of_changeset_attach_node(ocs, np);
509 if (ret) {
510 of_node_put(np);
511 return NULL;
512 }
513
514 return np;
515}
516EXPORT_SYMBOL(of_changeset_create_node);
517
518static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
519{
520 if (ce->action == OF_RECONFIG_ATTACH_NODE &&
521 of_node_check_flag(n: ce->np, OF_OVERLAY)) {
522 if (kref_read(kref: &ce->np->kobj.kref) > 1) {
523 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",
524 kref_read(&ce->np->kobj.kref), ce->np);
525 } else {
526 of_node_set_flag(n: ce->np, OF_OVERLAY_FREE_CSET);
527 }
528 }
529
530 of_node_put(ce->np);
531 list_del(entry: &ce->node);
532 kfree(objp: ce);
533}
534
535static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
536 struct of_changeset_entry *rce)
537{
538 memcpy(rce, ce, sizeof(*rce));
539
540 switch (ce->action) {
541 case OF_RECONFIG_ATTACH_NODE:
542 rce->action = OF_RECONFIG_DETACH_NODE;
543 break;
544 case OF_RECONFIG_DETACH_NODE:
545 rce->action = OF_RECONFIG_ATTACH_NODE;
546 break;
547 case OF_RECONFIG_ADD_PROPERTY:
548 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
549 break;
550 case OF_RECONFIG_REMOVE_PROPERTY:
551 rce->action = OF_RECONFIG_ADD_PROPERTY;
552 break;
553 case OF_RECONFIG_UPDATE_PROPERTY:
554 rce->old_prop = ce->prop;
555 rce->prop = ce->old_prop;
556 /* update was used but original property did not exist */
557 if (!rce->prop) {
558 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
559 rce->prop = ce->prop;
560 }
561 break;
562 }
563}
564
565static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
566 bool revert)
567{
568 struct of_reconfig_data rd;
569 struct of_changeset_entry ce_inverted;
570 int ret = 0;
571
572 if (revert) {
573 __of_changeset_entry_invert(ce, rce: &ce_inverted);
574 ce = &ce_inverted;
575 }
576
577 switch (ce->action) {
578 case OF_RECONFIG_ATTACH_NODE:
579 case OF_RECONFIG_DETACH_NODE:
580 memset(&rd, 0, sizeof(rd));
581 rd.dn = ce->np;
582 ret = of_reconfig_notify(action: ce->action, p: &rd);
583 break;
584 case OF_RECONFIG_ADD_PROPERTY:
585 case OF_RECONFIG_REMOVE_PROPERTY:
586 case OF_RECONFIG_UPDATE_PROPERTY:
587 ret = of_property_notify(action: ce->action, np: ce->np, prop: ce->prop, oldprop: ce->old_prop);
588 break;
589 default:
590 pr_err("invalid devicetree changeset action: %i\n",
591 (int)ce->action);
592 ret = -EINVAL;
593 }
594
595 if (ret)
596 pr_err("changeset notifier error @%pOF\n", ce->np);
597 return ret;
598}
599
600static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
601{
602 int ret = 0;
603
604 of_changeset_action_debug("apply: ", ce->action, ce->np, ce->prop);
605
606 switch (ce->action) {
607 case OF_RECONFIG_ATTACH_NODE:
608 __of_attach_node(np: ce->np);
609 break;
610 case OF_RECONFIG_DETACH_NODE:
611 __of_detach_node(np: ce->np);
612 break;
613 case OF_RECONFIG_ADD_PROPERTY:
614 ret = __of_add_property(np: ce->np, prop: ce->prop);
615 break;
616 case OF_RECONFIG_REMOVE_PROPERTY:
617 ret = __of_remove_property(np: ce->np, prop: ce->prop);
618 break;
619
620 case OF_RECONFIG_UPDATE_PROPERTY:
621 ret = __of_update_property(np: ce->np, newprop: ce->prop, oldprop: &ce->old_prop);
622 break;
623 default:
624 ret = -EINVAL;
625 }
626
627 if (ret) {
628 of_changeset_action_err("apply failed: ", ce->action, ce->np, ce->prop);
629 return ret;
630 }
631
632 return 0;
633}
634
635static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
636{
637 struct of_changeset_entry ce_inverted;
638
639 __of_changeset_entry_invert(ce, rce: &ce_inverted);
640 return __of_changeset_entry_apply(ce: &ce_inverted);
641}
642
643/**
644 * of_changeset_init - Initialize a changeset for use
645 *
646 * @ocs: changeset pointer
647 *
648 * Initialize a changeset structure
649 */
650void of_changeset_init(struct of_changeset *ocs)
651{
652 memset(ocs, 0, sizeof(*ocs));
653 INIT_LIST_HEAD(list: &ocs->entries);
654}
655EXPORT_SYMBOL_GPL(of_changeset_init);
656
657/**
658 * of_changeset_destroy - Destroy a changeset
659 *
660 * @ocs: changeset pointer
661 *
662 * Destroys a changeset. Note that if a changeset is applied,
663 * its changes to the tree cannot be reverted.
664 */
665void of_changeset_destroy(struct of_changeset *ocs)
666{
667 struct of_changeset_entry *ce, *cen;
668
669 list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
670 __of_changeset_entry_destroy(ce);
671}
672EXPORT_SYMBOL_GPL(of_changeset_destroy);
673
674/*
675 * Apply the changeset entries in @ocs.
676 * If apply fails, an attempt is made to revert the entries that were
677 * successfully applied.
678 *
679 * If multiple revert errors occur then only the final revert error is reported.
680 *
681 * Returns 0 on success, a negative error value in case of an error.
682 * If a revert error occurs, it is returned in *ret_revert.
683 */
684int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
685{
686 struct of_changeset_entry *ce;
687 int ret, ret_tmp;
688
689 pr_debug("changeset: applying...\n");
690 list_for_each_entry(ce, &ocs->entries, node) {
691 ret = __of_changeset_entry_apply(ce);
692 if (ret) {
693 pr_err("Error applying changeset (%d)\n", ret);
694 list_for_each_entry_continue_reverse(ce, &ocs->entries,
695 node) {
696 ret_tmp = __of_changeset_entry_revert(ce);
697 if (ret_tmp)
698 *ret_revert = ret_tmp;
699 }
700 return ret;
701 }
702 }
703
704 return 0;
705}
706
707/*
708 * Returns 0 on success, a negative error value in case of an error.
709 *
710 * If multiple changeset entry notification errors occur then only the
711 * final notification error is reported.
712 */
713int __of_changeset_apply_notify(struct of_changeset *ocs)
714{
715 struct of_changeset_entry *ce;
716 int ret = 0, ret_tmp;
717
718 pr_debug("changeset: emitting notifiers.\n");
719
720 /* drop the global lock while emitting notifiers */
721 mutex_unlock(lock: &of_mutex);
722 list_for_each_entry(ce, &ocs->entries, node) {
723 ret_tmp = __of_changeset_entry_notify(ce, revert: 0);
724 if (ret_tmp)
725 ret = ret_tmp;
726 }
727 mutex_lock(&of_mutex);
728 pr_debug("changeset: notifiers sent.\n");
729
730 return ret;
731}
732
733/*
734 * Returns 0 on success, a negative error value in case of an error.
735 *
736 * If a changeset entry apply fails, an attempt is made to revert any
737 * previous entries in the changeset. If any of the reverts fails,
738 * that failure is not reported. Thus the state of the device tree
739 * is unknown if an apply error occurs.
740 */
741static int __of_changeset_apply(struct of_changeset *ocs)
742{
743 int ret, ret_revert = 0;
744
745 ret = __of_changeset_apply_entries(ocs, ret_revert: &ret_revert);
746 if (!ret)
747 ret = __of_changeset_apply_notify(ocs);
748
749 return ret;
750}
751
752/**
753 * of_changeset_apply - Applies a changeset
754 *
755 * @ocs: changeset pointer
756 *
757 * Applies a changeset to the live tree.
758 * Any side-effects of live tree state changes are applied here on
759 * success, like creation/destruction of devices and side-effects
760 * like creation of sysfs properties and directories.
761 *
762 * Return: 0 on success, a negative error value in case of an error.
763 * On error the partially applied effects are reverted.
764 */
765int of_changeset_apply(struct of_changeset *ocs)
766{
767 int ret;
768
769 mutex_lock(&of_mutex);
770 ret = __of_changeset_apply(ocs);
771 mutex_unlock(lock: &of_mutex);
772
773 return ret;
774}
775EXPORT_SYMBOL_GPL(of_changeset_apply);
776
777/*
778 * Revert the changeset entries in @ocs.
779 * If revert fails, an attempt is made to re-apply the entries that were
780 * successfully removed.
781 *
782 * If multiple re-apply errors occur then only the final apply error is
783 * reported.
784 *
785 * Returns 0 on success, a negative error value in case of an error.
786 * If an apply error occurs, it is returned in *ret_apply.
787 */
788int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
789{
790 struct of_changeset_entry *ce;
791 int ret, ret_tmp;
792
793 pr_debug("changeset: reverting...\n");
794 list_for_each_entry_reverse(ce, &ocs->entries, node) {
795 ret = __of_changeset_entry_revert(ce);
796 if (ret) {
797 pr_err("Error reverting changeset (%d)\n", ret);
798 list_for_each_entry_continue(ce, &ocs->entries, node) {
799 ret_tmp = __of_changeset_entry_apply(ce);
800 if (ret_tmp)
801 *ret_apply = ret_tmp;
802 }
803 return ret;
804 }
805 }
806
807 return 0;
808}
809
810/*
811 * If multiple changeset entry notification errors occur then only the
812 * final notification error is reported.
813 */
814int __of_changeset_revert_notify(struct of_changeset *ocs)
815{
816 struct of_changeset_entry *ce;
817 int ret = 0, ret_tmp;
818
819 pr_debug("changeset: emitting notifiers.\n");
820
821 /* drop the global lock while emitting notifiers */
822 mutex_unlock(lock: &of_mutex);
823 list_for_each_entry_reverse(ce, &ocs->entries, node) {
824 ret_tmp = __of_changeset_entry_notify(ce, revert: 1);
825 if (ret_tmp)
826 ret = ret_tmp;
827 }
828 mutex_lock(&of_mutex);
829 pr_debug("changeset: notifiers sent.\n");
830
831 return ret;
832}
833
834static int __of_changeset_revert(struct of_changeset *ocs)
835{
836 int ret, ret_reply;
837
838 ret_reply = 0;
839 ret = __of_changeset_revert_entries(ocs, ret_apply: &ret_reply);
840
841 if (!ret)
842 ret = __of_changeset_revert_notify(ocs);
843
844 return ret;
845}
846
847/**
848 * of_changeset_revert - Reverts an applied changeset
849 *
850 * @ocs: changeset pointer
851 *
852 * Reverts a changeset returning the state of the tree to what it
853 * was before the application.
854 * Any side-effects like creation/destruction of devices and
855 * removal of sysfs properties and directories are applied.
856 *
857 * Return: 0 on success, a negative error value in case of an error.
858 */
859int of_changeset_revert(struct of_changeset *ocs)
860{
861 int ret;
862
863 mutex_lock(&of_mutex);
864 ret = __of_changeset_revert(ocs);
865 mutex_unlock(lock: &of_mutex);
866
867 return ret;
868}
869EXPORT_SYMBOL_GPL(of_changeset_revert);
870
871/**
872 * of_changeset_action - Add an action to the tail of the changeset list
873 *
874 * @ocs: changeset pointer
875 * @action: action to perform
876 * @np: Pointer to device node
877 * @prop: Pointer to property
878 *
879 * On action being one of:
880 * + OF_RECONFIG_ATTACH_NODE
881 * + OF_RECONFIG_DETACH_NODE,
882 * + OF_RECONFIG_ADD_PROPERTY
883 * + OF_RECONFIG_REMOVE_PROPERTY,
884 * + OF_RECONFIG_UPDATE_PROPERTY
885 *
886 * Return: 0 on success, a negative error value in case of an error.
887 */
888int of_changeset_action(struct of_changeset *ocs, unsigned long action,
889 struct device_node *np, struct property *prop)
890{
891 struct of_changeset_entry *ce;
892
893 if (WARN_ON(action >= ARRAY_SIZE(action_names)))
894 return -EINVAL;
895
896 ce = kzalloc(size: sizeof(*ce), GFP_KERNEL);
897 if (!ce)
898 return -ENOMEM;
899
900 /* get a reference to the node */
901 ce->action = action;
902 ce->np = of_node_get(np);
903 ce->prop = prop;
904
905 /* add it to the list */
906 list_add_tail(new: &ce->node, head: &ocs->entries);
907 return 0;
908}
909EXPORT_SYMBOL_GPL(of_changeset_action);
910
911static int of_changeset_add_prop_helper(struct of_changeset *ocs,
912 struct device_node *np,
913 const struct property *pp)
914{
915 struct property *new_pp;
916 int ret;
917
918 new_pp = __of_prop_dup(prop: pp, GFP_KERNEL);
919 if (!new_pp)
920 return -ENOMEM;
921
922 ret = of_changeset_add_property(ocs, np, prop: new_pp);
923 if (ret) {
924 kfree(objp: new_pp->name);
925 kfree(objp: new_pp->value);
926 kfree(objp: new_pp);
927 }
928
929 return ret;
930}
931
932/**
933 * of_changeset_add_prop_string - Add a string property to a changeset
934 *
935 * @ocs: changeset pointer
936 * @np: device node pointer
937 * @prop_name: name of the property to be added
938 * @str: pointer to null terminated string
939 *
940 * Create a string property and add it to a changeset.
941 *
942 * Return: 0 on success, a negative error value in case of an error.
943 */
944int of_changeset_add_prop_string(struct of_changeset *ocs,
945 struct device_node *np,
946 const char *prop_name, const char *str)
947{
948 struct property prop;
949
950 prop.name = (char *)prop_name;
951 prop.length = strlen(str) + 1;
952 prop.value = (void *)str;
953
954 return of_changeset_add_prop_helper(ocs, np, pp: &prop);
955}
956EXPORT_SYMBOL_GPL(of_changeset_add_prop_string);
957
958/**
959 * of_changeset_add_prop_string_array - Add a string list property to
960 * a changeset
961 *
962 * @ocs: changeset pointer
963 * @np: device node pointer
964 * @prop_name: name of the property to be added
965 * @str_array: pointer to an array of null terminated strings
966 * @sz: number of string array elements
967 *
968 * Create a string list property and add it to a changeset.
969 *
970 * Return: 0 on success, a negative error value in case of an error.
971 */
972int of_changeset_add_prop_string_array(struct of_changeset *ocs,
973 struct device_node *np,
974 const char *prop_name,
975 const char **str_array, size_t sz)
976{
977 struct property prop;
978 int i, ret;
979 char *vp;
980
981 prop.name = (char *)prop_name;
982
983 prop.length = 0;
984 for (i = 0; i < sz; i++)
985 prop.length += strlen(str_array[i]) + 1;
986
987 prop.value = kmalloc(size: prop.length, GFP_KERNEL);
988 if (!prop.value)
989 return -ENOMEM;
990
991 vp = prop.value;
992 for (i = 0; i < sz; i++) {
993 vp += snprintf(buf: vp, size: (char *)prop.value + prop.length - vp, fmt: "%s",
994 str_array[i]) + 1;
995 }
996 ret = of_changeset_add_prop_helper(ocs, np, pp: &prop);
997 kfree(objp: prop.value);
998
999 return ret;
1000}
1001EXPORT_SYMBOL_GPL(of_changeset_add_prop_string_array);
1002
1003/**
1004 * of_changeset_add_prop_u32_array - Add a property of 32 bit integers
1005 * property to a changeset
1006 *
1007 * @ocs: changeset pointer
1008 * @np: device node pointer
1009 * @prop_name: name of the property to be added
1010 * @array: pointer to an array of 32 bit integers
1011 * @sz: number of array elements
1012 *
1013 * Create a property of 32 bit integers and add it to a changeset.
1014 *
1015 * Return: 0 on success, a negative error value in case of an error.
1016 */
1017int of_changeset_add_prop_u32_array(struct of_changeset *ocs,
1018 struct device_node *np,
1019 const char *prop_name,
1020 const u32 *array, size_t sz)
1021{
1022 struct property prop;
1023 __be32 *val;
1024 int i, ret;
1025
1026 val = kcalloc(n: sz, size: sizeof(__be32), GFP_KERNEL);
1027 if (!val)
1028 return -ENOMEM;
1029
1030 for (i = 0; i < sz; i++)
1031 val[i] = cpu_to_be32(array[i]);
1032 prop.name = (char *)prop_name;
1033 prop.length = sizeof(u32) * sz;
1034 prop.value = (void *)val;
1035
1036 ret = of_changeset_add_prop_helper(ocs, np, pp: &prop);
1037 kfree(objp: val);
1038
1039 return ret;
1040}
1041EXPORT_SYMBOL_GPL(of_changeset_add_prop_u32_array);
1042

source code of linux/drivers/of/dynamic.c