2 * Support for dynamic device trees.
4 * On some platforms, the device tree can be manipulated at runtime.
5 * The routines in this section support adding, removing and changing
10 #include <linux/spinlock.h>
11 #include <linux/slab.h>
12 #include <linux/string.h>
13 #include <linux/proc_fs.h>
15 #include "of_private.h"
18 * of_node_get() - Increment refcount of a node
19 * @node: Node to inc refcount, NULL is supported to simplify writing of
24 struct device_node *of_node_get(struct device_node *node)
27 kobject_get(&node->kobj);
30 EXPORT_SYMBOL(of_node_get);
33 * of_node_put() - Decrement refcount of a node
34 * @node: Node to dec refcount, NULL is supported to simplify writing of
37 void of_node_put(struct device_node *node)
40 kobject_put(&node->kobj);
42 EXPORT_SYMBOL(of_node_put);
44 void __of_detach_node_sysfs(struct device_node *np)
48 if (!IS_ENABLED(CONFIG_SYSFS))
51 BUG_ON(!of_node_is_initialized(np));
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);
62 /* finally remove the kobj_init ref */
66 static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
68 int of_reconfig_notifier_register(struct notifier_block *nb)
70 return blocking_notifier_chain_register(&of_reconfig_chain, nb);
72 EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
74 int of_reconfig_notifier_unregister(struct notifier_block *nb)
76 return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
78 EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
80 int of_reconfig_notify(unsigned long action, void *p)
84 rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
85 return notifier_to_errno(rc);
88 int of_property_notify(int action, struct device_node *np,
89 struct property *prop, struct property *oldprop)
91 struct of_prop_reconfig pr;
93 /* only call notifiers if the node is attached */
94 if (!of_node_is_attached(np))
99 pr.old_prop = oldprop;
100 return of_reconfig_notify(action, &pr);
103 void __of_attach_node(struct device_node *np)
105 const __be32 *phandle;
108 np->name = __of_get_property(np, "name", NULL) ? : "<NULL>";
109 np->type = __of_get_property(np, "device_type", NULL) ? : "<NULL>";
111 phandle = __of_get_property(np, "phandle", &sz);
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;
119 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);
127 * of_attach_node() - Plug a device node into the tree and global list.
129 int of_attach_node(struct device_node *np)
133 mutex_lock(&of_mutex);
134 raw_spin_lock_irqsave(&devtree_lock, flags);
135 __of_attach_node(np);
136 raw_spin_unlock_irqrestore(&devtree_lock, flags);
138 __of_attach_node_sysfs(np);
139 mutex_unlock(&of_mutex);
141 of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, np);
146 void __of_detach_node(struct device_node *np)
148 struct device_node *parent;
150 if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
154 if (WARN_ON(!parent))
157 if (of_allnodes == np)
158 of_allnodes = np->allnext;
160 struct device_node *prev;
161 for (prev = of_allnodes;
163 prev = prev->allnext)
165 prev->allnext = np->allnext;
168 if (parent->child == np)
169 parent->child = np->sibling;
171 struct device_node *prevsib;
172 for (prevsib = np->parent->child;
173 prevsib->sibling != np;
174 prevsib = prevsib->sibling)
176 prevsib->sibling = np->sibling;
179 of_node_set_flag(np, OF_DETACHED);
183 * of_detach_node() - "Unplug" a node from the device tree.
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.
188 int of_detach_node(struct device_node *np)
193 mutex_lock(&of_mutex);
194 raw_spin_lock_irqsave(&devtree_lock, flags);
195 __of_detach_node(np);
196 raw_spin_unlock_irqrestore(&devtree_lock, flags);
198 __of_detach_node_sysfs(np);
199 mutex_unlock(&of_mutex);
201 of_reconfig_notify(OF_RECONFIG_DETACH_NODE, np);
207 * of_node_release() - release a dynamically allocated node
208 * @kref: kref element of the node to be released
210 * In of_node_put() this function is passed to kref_put() as the destructor.
212 void of_node_release(struct kobject *kobj)
214 struct device_node *node = kobj_to_device_node(kobj);
215 struct property *prop = node->properties;
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);
224 if (!of_node_check_flag(node, OF_DYNAMIC))
228 struct property *next = prop->next;
235 prop = node->deadprops;
236 node->deadprops = NULL;
239 kfree(node->full_name);
245 * __of_prop_dup - Copy a property dynamically.
246 * @prop: Property to copy
247 * @allocflags: Allocation flags (typically pass GFP_KERNEL)
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.
255 struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
257 struct property *new;
259 new = kzalloc(sizeof(*new), allocflags);
264 * NOTE: There is no check for zero length value.
265 * In case of a boolean property, this will allocate a value
266 * of zero bytes. We do this to work around the use
267 * of of_get_property() calls on boolean values.
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)
275 /* mark the property as dynamic */
276 of_property_set_flag(new, OF_DYNAMIC);
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)
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.
297 struct device_node *__of_node_alloc(const char *full_name, gfp_t allocflags)
299 struct device_node *node;
301 node = kzalloc(sizeof(*node), allocflags);
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)
316 kfree(node->full_name);
321 static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
329 static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
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,
337 case OF_RECONFIG_REMOVE_PROPERTY:
338 pr_debug("%p: %s %s/%s\n",
339 ce, "REMOVE_PROPERTY", ce->np->full_name,
342 case OF_RECONFIG_UPDATE_PROPERTY:
343 pr_debug("%p: %s %s/%s\n",
344 ce, "UPDATE_PROPERTY", ce->np->full_name,
347 case OF_RECONFIG_ATTACH_NODE:
348 pr_debug("%p: %s %s\n",
349 ce, "ATTACH_NODE ", ce->np->full_name);
351 case OF_RECONFIG_DETACH_NODE:
352 pr_debug("%p: %s %s\n",
353 ce, "DETACH_NODE ", ce->np->full_name);
358 static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
364 static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
365 struct of_changeset_entry *rce)
367 memcpy(rce, ce, sizeof(*rce));
369 switch (ce->action) {
370 case OF_RECONFIG_ATTACH_NODE:
371 rce->action = OF_RECONFIG_DETACH_NODE;
373 case OF_RECONFIG_DETACH_NODE:
374 rce->action = OF_RECONFIG_ATTACH_NODE;
376 case OF_RECONFIG_ADD_PROPERTY:
377 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
379 case OF_RECONFIG_REMOVE_PROPERTY:
380 rce->action = OF_RECONFIG_ADD_PROPERTY;
382 case OF_RECONFIG_UPDATE_PROPERTY:
383 rce->old_prop = ce->prop;
384 rce->prop = ce->old_prop;
389 static void __of_changeset_entry_notify(struct of_changeset_entry *ce, bool revert)
391 struct of_changeset_entry ce_inverted;
395 __of_changeset_entry_invert(ce, &ce_inverted);
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);
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);
410 pr_err("%s: invalid devicetree changeset action: %i\n", __func__,
416 pr_err("%s: notifier error @%s\n", __func__, ce->np->full_name);
419 static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
421 struct property *old_prop, **propp;
425 __of_changeset_entry_dump(ce);
427 raw_spin_lock_irqsave(&devtree_lock, flags);
428 switch (ce->action) {
429 case OF_RECONFIG_ATTACH_NODE:
430 __of_attach_node(ce->np);
432 case OF_RECONFIG_DETACH_NODE:
433 __of_detach_node(ce->np);
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;
445 ret = __of_add_property(ce->np, ce->prop);
447 pr_err("%s: add_property failed @%s/%s\n",
448 __func__, ce->np->full_name,
453 case OF_RECONFIG_REMOVE_PROPERTY:
454 ret = __of_remove_property(ce->np, ce->prop);
456 pr_err("%s: remove_property failed @%s/%s\n",
457 __func__, ce->np->full_name,
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;
473 ret = __of_update_property(ce->np, ce->prop, &old_prop);
475 pr_err("%s: update_property failed @%s/%s\n",
476 __func__, ce->np->full_name,
484 raw_spin_unlock_irqrestore(&devtree_lock, flags);
489 switch (ce->action) {
490 case OF_RECONFIG_ATTACH_NODE:
491 __of_attach_node_sysfs(ce->np);
493 case OF_RECONFIG_DETACH_NODE:
494 __of_detach_node_sysfs(ce->np);
496 case OF_RECONFIG_ADD_PROPERTY:
497 /* ignore duplicate names */
498 __of_add_property_sysfs(ce->np, ce->prop);
500 case OF_RECONFIG_REMOVE_PROPERTY:
501 __of_remove_property_sysfs(ce->np, ce->prop);
503 case OF_RECONFIG_UPDATE_PROPERTY:
504 __of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
511 static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
513 struct of_changeset_entry ce_inverted;
515 __of_changeset_entry_invert(ce, &ce_inverted);
516 return __of_changeset_entry_apply(&ce_inverted);
520 * of_changeset_init - Initialize a changeset for use
522 * @ocs: changeset pointer
524 * Initialize a changeset structure
526 void of_changeset_init(struct of_changeset *ocs)
528 memset(ocs, 0, sizeof(*ocs));
529 INIT_LIST_HEAD(&ocs->entries);
533 * of_changeset_destroy - Destroy a changeset
535 * @ocs: changeset pointer
537 * Destroys a changeset. Note that if a changeset is applied,
538 * its changes to the tree cannot be reverted.
540 void of_changeset_destroy(struct of_changeset *ocs)
542 struct of_changeset_entry *ce, *cen;
544 list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
545 __of_changeset_entry_destroy(ce);
549 * of_changeset_apply - Applies a changeset
551 * @ocs: changeset pointer
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.
560 int of_changeset_apply(struct of_changeset *ocs)
562 struct of_changeset_entry *ce;
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);
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);
576 pr_debug("of_changeset: applied, emitting notifiers.\n");
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");
589 * of_changeset_revert - Reverts an applied changeset
591 * @ocs: changeset pointer
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.
599 int of_changeset_revert(struct of_changeset *ocs)
601 struct of_changeset_entry *ce;
604 pr_debug("of_changeset: reverting...\n");
605 list_for_each_entry_reverse(ce, &ocs->entries, node) {
606 ret = __of_changeset_entry_revert(ce);
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);
614 pr_debug("of_changeset: reverted, emitting notifiers.\n");
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");
627 * of_changeset_action - Perform a changeset action
629 * @ocs: changeset pointer
630 * @action: action to perform
631 * @np: Pointer to device node
632 * @prop: Pointer to property
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.
642 int of_changeset_action(struct of_changeset *ocs, unsigned long action,
643 struct device_node *np, struct property *prop)
645 struct of_changeset_entry *ce;
647 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
649 pr_err("%s: Failed to allocate\n", __func__);
652 /* get a reference to the node */
654 ce->np = of_node_get(np);
657 if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
658 ce->old_prop = of_find_property(np, prop->name, NULL);
660 /* add it to the list */
661 list_add_tail(&ce->node, &ocs->entries);