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