blob: f297891d852908ae3e78fe9bfa2bfe5b231875e6 [file] [log] [blame]
Grant Likely6afc0dc2014-06-26 15:40:48 +01001/*
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
Grant Likely8a2b22a2014-07-23 17:05:06 -060044void __of_detach_node_sysfs(struct device_node *np)
Grant Likely6afc0dc2014-06-26 15:40:48 +010045{
46 struct property *pp;
47
Gaurav Minochaef69d742014-09-05 09:56:13 -070048 if (!IS_ENABLED(CONFIG_SYSFS))
49 return;
50
Grant Likely6afc0dc2014-06-26 15:40:48 +010051 BUG_ON(!of_node_is_initialized(np));
Grant Likely8a2b22a2014-07-23 17:05:06 -060052 if (!of_kset)
53 return;
Grant Likely6afc0dc2014-06-26 15:40:48 +010054
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
80int of_reconfig_notify(unsigned long action, void *p)
81{
82 int rc;
83
84 rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
85 return notifier_to_errno(rc);
86}
87
88int of_property_notify(int action, struct device_node *np,
Grant Likely259092a2014-07-16 12:48:23 -060089 struct property *prop, struct property *oldprop)
Grant Likely6afc0dc2014-06-26 15:40:48 +010090{
91 struct of_prop_reconfig pr;
92
93 /* only call notifiers if the node is attached */
94 if (!of_node_is_attached(np))
95 return 0;
96
97 pr.dn = np;
98 pr.prop = prop;
Grant Likely259092a2014-07-16 12:48:23 -060099 pr.old_prop = oldprop;
Grant Likely6afc0dc2014-06-26 15:40:48 +0100100 return of_reconfig_notify(action, &pr);
101}
102
Pantelis Antonioud8c50082014-07-04 19:58:46 +0300103void __of_attach_node(struct device_node *np)
104{
Grant Likelya25095d2014-07-15 23:25:43 -0600105 const __be32 *phandle;
106 int sz;
107
108 np->name = __of_get_property(np, "name", NULL) ? : "<NULL>";
109 np->type = __of_get_property(np, "device_type", NULL) ? : "<NULL>";
110
111 phandle = __of_get_property(np, "phandle", &sz);
112 if (!phandle)
113 phandle = __of_get_property(np, "linux,phandle", &sz);
114 if (IS_ENABLED(PPC_PSERIES) && !phandle)
115 phandle = __of_get_property(np, "ibm,phandle", &sz);
116 np->phandle = (phandle && (sz >= 4)) ? be32_to_cpup(phandle) : 0;
117
Grant Likely6162dbe2014-07-16 08:48:46 -0600118 np->child = NULL;
Pantelis Antonioud8c50082014-07-04 19:58:46 +0300119 np->sibling = np->parent->child;
120 np->allnext = np->parent->allnext;
121 np->parent->allnext = np;
122 np->parent->child = np;
123 of_node_clear_flag(np, OF_DETACHED);
124}
125
Grant Likely6afc0dc2014-06-26 15:40:48 +0100126/**
127 * of_attach_node() - Plug a device node into the tree and global list.
128 */
129int of_attach_node(struct device_node *np)
130{
131 unsigned long flags;
Grant Likely6afc0dc2014-06-26 15:40:48 +0100132
Grant Likely8a2b22a2014-07-23 17:05:06 -0600133 mutex_lock(&of_mutex);
Grant Likely6afc0dc2014-06-26 15:40:48 +0100134 raw_spin_lock_irqsave(&devtree_lock, flags);
Pantelis Antonioud8c50082014-07-04 19:58:46 +0300135 __of_attach_node(np);
Grant Likely6afc0dc2014-06-26 15:40:48 +0100136 raw_spin_unlock_irqrestore(&devtree_lock, flags);
137
Grant Likely8a2b22a2014-07-23 17:05:06 -0600138 __of_attach_node_sysfs(np);
139 mutex_unlock(&of_mutex);
Grant Likely259092a2014-07-16 12:48:23 -0600140
141 of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, np);
142
Grant Likely6afc0dc2014-06-26 15:40:48 +0100143 return 0;
144}
145
Pantelis Antonioud8c50082014-07-04 19:58:46 +0300146void __of_detach_node(struct device_node *np)
Grant Likely6afc0dc2014-06-26 15:40:48 +0100147{
148 struct device_node *parent;
Grant Likely6afc0dc2014-06-26 15:40:48 +0100149
Pantelis Antonioud8c50082014-07-04 19:58:46 +0300150 if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
151 return;
Grant Likely6afc0dc2014-06-26 15:40:48 +0100152
153 parent = np->parent;
Pantelis Antonioud8c50082014-07-04 19:58:46 +0300154 if (WARN_ON(!parent))
155 return;
Grant Likely6afc0dc2014-06-26 15:40:48 +0100156
157 if (of_allnodes == np)
158 of_allnodes = np->allnext;
159 else {
160 struct device_node *prev;
161 for (prev = of_allnodes;
162 prev->allnext != np;
163 prev = prev->allnext)
164 ;
165 prev->allnext = np->allnext;
166 }
167
168 if (parent->child == np)
169 parent->child = np->sibling;
170 else {
171 struct device_node *prevsib;
172 for (prevsib = np->parent->child;
173 prevsib->sibling != np;
174 prevsib = prevsib->sibling)
175 ;
176 prevsib->sibling = np->sibling;
177 }
178
179 of_node_set_flag(np, OF_DETACHED);
Pantelis Antonioud8c50082014-07-04 19:58:46 +0300180}
181
182/**
183 * of_detach_node() - "Unplug" a node from the device tree.
184 *
185 * The caller must hold a reference to the node. The memory associated with
186 * the node is not freed until its refcount goes to zero.
187 */
188int of_detach_node(struct device_node *np)
189{
190 unsigned long flags;
191 int rc = 0;
192
Grant Likely8a2b22a2014-07-23 17:05:06 -0600193 mutex_lock(&of_mutex);
Pantelis Antonioud8c50082014-07-04 19:58:46 +0300194 raw_spin_lock_irqsave(&devtree_lock, flags);
195 __of_detach_node(np);
Grant Likely6afc0dc2014-06-26 15:40:48 +0100196 raw_spin_unlock_irqrestore(&devtree_lock, flags);
197
Grant Likely8a2b22a2014-07-23 17:05:06 -0600198 __of_detach_node_sysfs(np);
199 mutex_unlock(&of_mutex);
Grant Likely259092a2014-07-16 12:48:23 -0600200
201 of_reconfig_notify(OF_RECONFIG_DETACH_NODE, np);
202
Grant Likely6afc0dc2014-06-26 15:40:48 +0100203 return rc;
204}
205
206/**
207 * of_node_release() - release a dynamically allocated node
208 * @kref: kref element of the node to be released
209 *
210 * In of_node_put() this function is passed to kref_put() as the destructor.
211 */
212void of_node_release(struct kobject *kobj)
213{
214 struct device_node *node = kobj_to_device_node(kobj);
215 struct property *prop = node->properties;
216
217 /* We should never be releasing nodes that haven't been detached. */
218 if (!of_node_check_flag(node, OF_DETACHED)) {
219 pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name);
220 dump_stack();
221 return;
222 }
223
224 if (!of_node_check_flag(node, OF_DYNAMIC))
225 return;
226
227 while (prop) {
228 struct property *next = prop->next;
229 kfree(prop->name);
230 kfree(prop->value);
231 kfree(prop);
232 prop = next;
233
234 if (!prop) {
235 prop = node->deadprops;
236 node->deadprops = NULL;
237 }
238 }
239 kfree(node->full_name);
240 kfree(node->data);
241 kfree(node);
242}
Pantelis Antoniou69843392014-07-04 19:58:47 +0300243
244/**
245 * __of_prop_dup - Copy a property dynamically.
246 * @prop: Property to copy
247 * @allocflags: Allocation flags (typically pass GFP_KERNEL)
248 *
249 * Copy a property by dynamically allocating the memory of both the
250 * property stucture and the property name & contents. The property's
251 * flags have the OF_DYNAMIC bit set so that we can differentiate between
252 * dynamically allocated properties and not.
253 * Returns the newly allocated property or NULL on out of memory error.
254 */
255struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
256{
257 struct property *new;
258
259 new = kzalloc(sizeof(*new), allocflags);
260 if (!new)
261 return NULL;
262
263 /*
264 * NOTE: There is no check for zero length value.
Grant Likelyb6ae5dc2014-07-26 10:58:43 -0600265 * In case of a boolean property, this will allocate a value
Pantelis Antoniou69843392014-07-04 19:58:47 +0300266 * of zero bytes. We do this to work around the use
267 * of of_get_property() calls on boolean values.
268 */
269 new->name = kstrdup(prop->name, allocflags);
270 new->value = kmemdup(prop->value, prop->length, allocflags);
271 new->length = prop->length;
272 if (!new->name || !new->value)
273 goto err_free;
274
275 /* mark the property as dynamic */
276 of_property_set_flag(new, OF_DYNAMIC);
277
278 return new;
279
280 err_free:
281 kfree(new->name);
282 kfree(new->value);
283 kfree(new);
284 return NULL;
285}
286
287/**
288 * __of_node_alloc() - Create an empty device node dynamically.
289 * @full_name: Full name of the new device node
290 * @allocflags: Allocation flags (typically pass GFP_KERNEL)
291 *
292 * Create an empty device tree node, suitable for further modification.
293 * The node data are dynamically allocated and all the node flags
294 * have the OF_DYNAMIC & OF_DETACHED bits set.
295 * Returns the newly allocated node or NULL on out of memory error.
296 */
297struct device_node *__of_node_alloc(const char *full_name, gfp_t allocflags)
298{
299 struct device_node *node;
300
301 node = kzalloc(sizeof(*node), allocflags);
302 if (!node)
303 return NULL;
304
305 node->full_name = kstrdup(full_name, allocflags);
306 of_node_set_flag(node, OF_DYNAMIC);
307 of_node_set_flag(node, OF_DETACHED);
308 if (!node->full_name)
309 goto err_free;
310
311 of_node_init(node);
312
313 return node;
314
315 err_free:
316 kfree(node->full_name);
317 kfree(node);
318 return NULL;
319}
Pantelis Antoniou201c9102014-07-04 19:58:49 +0300320
321static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
322{
323 of_node_put(ce->np);
324 list_del(&ce->node);
325 kfree(ce);
326}
327
328#ifdef DEBUG
329static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
330{
331 switch (ce->action) {
332 case OF_RECONFIG_ADD_PROPERTY:
333 pr_debug("%p: %s %s/%s\n",
334 ce, "ADD_PROPERTY ", ce->np->full_name,
335 ce->prop->name);
336 break;
337 case OF_RECONFIG_REMOVE_PROPERTY:
338 pr_debug("%p: %s %s/%s\n",
339 ce, "REMOVE_PROPERTY", ce->np->full_name,
340 ce->prop->name);
341 break;
342 case OF_RECONFIG_UPDATE_PROPERTY:
343 pr_debug("%p: %s %s/%s\n",
344 ce, "UPDATE_PROPERTY", ce->np->full_name,
345 ce->prop->name);
346 break;
347 case OF_RECONFIG_ATTACH_NODE:
348 pr_debug("%p: %s %s\n",
349 ce, "ATTACH_NODE ", ce->np->full_name);
350 break;
351 case OF_RECONFIG_DETACH_NODE:
352 pr_debug("%p: %s %s\n",
353 ce, "DETACH_NODE ", ce->np->full_name);
354 break;
355 }
356}
357#else
358static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
359{
360 /* empty */
361}
362#endif
363
364static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
365 struct of_changeset_entry *rce)
366{
367 memcpy(rce, ce, sizeof(*rce));
368
369 switch (ce->action) {
370 case OF_RECONFIG_ATTACH_NODE:
371 rce->action = OF_RECONFIG_DETACH_NODE;
372 break;
373 case OF_RECONFIG_DETACH_NODE:
374 rce->action = OF_RECONFIG_ATTACH_NODE;
375 break;
376 case OF_RECONFIG_ADD_PROPERTY:
377 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
378 break;
379 case OF_RECONFIG_REMOVE_PROPERTY:
380 rce->action = OF_RECONFIG_ADD_PROPERTY;
381 break;
382 case OF_RECONFIG_UPDATE_PROPERTY:
383 rce->old_prop = ce->prop;
384 rce->prop = ce->old_prop;
385 break;
386 }
387}
388
389static void __of_changeset_entry_notify(struct of_changeset_entry *ce, bool revert)
390{
391 struct of_changeset_entry ce_inverted;
392 int ret;
393
394 if (revert) {
395 __of_changeset_entry_invert(ce, &ce_inverted);
396 ce = &ce_inverted;
397 }
398
399 switch (ce->action) {
400 case OF_RECONFIG_ATTACH_NODE:
401 case OF_RECONFIG_DETACH_NODE:
402 ret = of_reconfig_notify(ce->action, ce->np);
403 break;
404 case OF_RECONFIG_ADD_PROPERTY:
405 case OF_RECONFIG_REMOVE_PROPERTY:
406 case OF_RECONFIG_UPDATE_PROPERTY:
407 ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
408 break;
409 default:
410 pr_err("%s: invalid devicetree changeset action: %i\n", __func__,
411 (int)ce->action);
412 return;
413 }
414
415 if (ret)
416 pr_err("%s: notifier error @%s\n", __func__, ce->np->full_name);
417}
418
419static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
420{
421 struct property *old_prop, **propp;
422 unsigned long flags;
423 int ret = 0;
424
425 __of_changeset_entry_dump(ce);
426
427 raw_spin_lock_irqsave(&devtree_lock, flags);
428 switch (ce->action) {
429 case OF_RECONFIG_ATTACH_NODE:
430 __of_attach_node(ce->np);
431 break;
432 case OF_RECONFIG_DETACH_NODE:
433 __of_detach_node(ce->np);
434 break;
435 case OF_RECONFIG_ADD_PROPERTY:
436 /* If the property is in deadprops then it must be removed */
437 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
438 if (*propp == ce->prop) {
439 *propp = ce->prop->next;
440 ce->prop->next = NULL;
441 break;
442 }
443 }
444
445 ret = __of_add_property(ce->np, ce->prop);
446 if (ret) {
447 pr_err("%s: add_property failed @%s/%s\n",
448 __func__, ce->np->full_name,
449 ce->prop->name);
450 break;
451 }
452 break;
453 case OF_RECONFIG_REMOVE_PROPERTY:
454 ret = __of_remove_property(ce->np, ce->prop);
455 if (ret) {
456 pr_err("%s: remove_property failed @%s/%s\n",
457 __func__, ce->np->full_name,
458 ce->prop->name);
459 break;
460 }
461 break;
462
463 case OF_RECONFIG_UPDATE_PROPERTY:
464 /* If the property is in deadprops then it must be removed */
465 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
466 if (*propp == ce->prop) {
467 *propp = ce->prop->next;
468 ce->prop->next = NULL;
469 break;
470 }
471 }
472
473 ret = __of_update_property(ce->np, ce->prop, &old_prop);
474 if (ret) {
475 pr_err("%s: update_property failed @%s/%s\n",
476 __func__, ce->np->full_name,
477 ce->prop->name);
478 break;
479 }
480 break;
481 default:
482 ret = -EINVAL;
483 }
484 raw_spin_unlock_irqrestore(&devtree_lock, flags);
485
486 if (ret)
487 return ret;
488
489 switch (ce->action) {
490 case OF_RECONFIG_ATTACH_NODE:
491 __of_attach_node_sysfs(ce->np);
492 break;
493 case OF_RECONFIG_DETACH_NODE:
494 __of_detach_node_sysfs(ce->np);
495 break;
496 case OF_RECONFIG_ADD_PROPERTY:
497 /* ignore duplicate names */
498 __of_add_property_sysfs(ce->np, ce->prop);
499 break;
500 case OF_RECONFIG_REMOVE_PROPERTY:
501 __of_remove_property_sysfs(ce->np, ce->prop);
502 break;
503 case OF_RECONFIG_UPDATE_PROPERTY:
504 __of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
505 break;
506 }
507
508 return 0;
509}
510
511static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
512{
513 struct of_changeset_entry ce_inverted;
514
515 __of_changeset_entry_invert(ce, &ce_inverted);
516 return __of_changeset_entry_apply(&ce_inverted);
517}
518
519/**
520 * of_changeset_init - Initialize a changeset for use
521 *
522 * @ocs: changeset pointer
523 *
524 * Initialize a changeset structure
525 */
526void of_changeset_init(struct of_changeset *ocs)
527{
528 memset(ocs, 0, sizeof(*ocs));
529 INIT_LIST_HEAD(&ocs->entries);
530}
531
532/**
533 * of_changeset_destroy - Destroy a changeset
534 *
535 * @ocs: changeset pointer
536 *
537 * Destroys a changeset. Note that if a changeset is applied,
538 * its changes to the tree cannot be reverted.
539 */
540void of_changeset_destroy(struct of_changeset *ocs)
541{
542 struct of_changeset_entry *ce, *cen;
543
544 list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
545 __of_changeset_entry_destroy(ce);
546}
547
548/**
549 * of_changeset_apply - Applies a changeset
550 *
551 * @ocs: changeset pointer
552 *
553 * Applies a changeset to the live tree.
554 * Any side-effects of live tree state changes are applied here on
555 * sucess, like creation/destruction of devices and side-effects
556 * like creation of sysfs properties and directories.
557 * Returns 0 on success, a negative error value in case of an error.
558 * On error the partially applied effects are reverted.
559 */
560int of_changeset_apply(struct of_changeset *ocs)
561{
562 struct of_changeset_entry *ce;
563 int ret;
564
565 /* perform the rest of the work */
566 pr_debug("of_changeset: applying...\n");
567 list_for_each_entry(ce, &ocs->entries, node) {
568 ret = __of_changeset_entry_apply(ce);
569 if (ret) {
570 pr_err("%s: Error applying changeset (%d)\n", __func__, ret);
571 list_for_each_entry_continue_reverse(ce, &ocs->entries, node)
572 __of_changeset_entry_revert(ce);
573 return ret;
574 }
575 }
576 pr_debug("of_changeset: applied, emitting notifiers.\n");
577
578 /* drop the global lock while emitting notifiers */
579 mutex_unlock(&of_mutex);
580 list_for_each_entry(ce, &ocs->entries, node)
581 __of_changeset_entry_notify(ce, 0);
582 mutex_lock(&of_mutex);
583 pr_debug("of_changeset: notifiers sent.\n");
584
585 return 0;
586}
587
588/**
589 * of_changeset_revert - Reverts an applied changeset
590 *
591 * @ocs: changeset pointer
592 *
593 * Reverts a changeset returning the state of the tree to what it
594 * was before the application.
595 * Any side-effects like creation/destruction of devices and
596 * removal of sysfs properties and directories are applied.
597 * Returns 0 on success, a negative error value in case of an error.
598 */
599int of_changeset_revert(struct of_changeset *ocs)
600{
601 struct of_changeset_entry *ce;
602 int ret;
603
604 pr_debug("of_changeset: reverting...\n");
605 list_for_each_entry_reverse(ce, &ocs->entries, node) {
606 ret = __of_changeset_entry_revert(ce);
607 if (ret) {
608 pr_err("%s: Error reverting changeset (%d)\n", __func__, ret);
609 list_for_each_entry_continue(ce, &ocs->entries, node)
610 __of_changeset_entry_apply(ce);
611 return ret;
612 }
613 }
614 pr_debug("of_changeset: reverted, emitting notifiers.\n");
615
616 /* drop the global lock while emitting notifiers */
617 mutex_unlock(&of_mutex);
618 list_for_each_entry_reverse(ce, &ocs->entries, node)
619 __of_changeset_entry_notify(ce, 1);
620 mutex_lock(&of_mutex);
621 pr_debug("of_changeset: notifiers sent.\n");
622
623 return 0;
624}
625
626/**
627 * of_changeset_action - Perform a changeset action
628 *
629 * @ocs: changeset pointer
630 * @action: action to perform
631 * @np: Pointer to device node
632 * @prop: Pointer to property
633 *
634 * On action being one of:
635 * + OF_RECONFIG_ATTACH_NODE
636 * + OF_RECONFIG_DETACH_NODE,
637 * + OF_RECONFIG_ADD_PROPERTY
638 * + OF_RECONFIG_REMOVE_PROPERTY,
639 * + OF_RECONFIG_UPDATE_PROPERTY
640 * Returns 0 on success, a negative error value in case of an error.
641 */
642int of_changeset_action(struct of_changeset *ocs, unsigned long action,
643 struct device_node *np, struct property *prop)
644{
645 struct of_changeset_entry *ce;
646
647 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
648 if (!ce) {
649 pr_err("%s: Failed to allocate\n", __func__);
650 return -ENOMEM;
651 }
652 /* get a reference to the node */
653 ce->action = action;
654 ce->np = of_node_get(np);
655 ce->prop = prop;
656
657 if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
658 ce->old_prop = of_find_property(np, prop->name, NULL);
659
660 /* add it to the list */
661 list_add_tail(&ce->node, &ocs->entries);
662 return 0;
663}