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