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 BUG_ON(!of_node_is_initialized(np));
52 /* only remove properties if on sysfs */
53 if (of_node_is_attached(np)) {
54 for_each_property_of_node(np, pp)
55 sysfs_remove_bin_file(&np->kobj, &pp->attr);
56 kobject_del(&np->kobj);
59 /* finally remove the kobj_init ref */
63 static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
65 int of_reconfig_notifier_register(struct notifier_block *nb)
67 return blocking_notifier_chain_register(&of_reconfig_chain, nb);
69 EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
71 int of_reconfig_notifier_unregister(struct notifier_block *nb)
73 return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
75 EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
77 int of_reconfig_notify(unsigned long action, void *p)
81 rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
82 return notifier_to_errno(rc);
85 int of_property_notify(int action, struct device_node *np,
86 struct property *prop, struct property *oldprop)
88 struct of_prop_reconfig pr;
90 /* only call notifiers if the node is attached */
91 if (!of_node_is_attached(np))
96 pr.old_prop = oldprop;
97 return of_reconfig_notify(action, &pr);
100 void __of_attach_node(struct device_node *np)
102 const __be32 *phandle;
105 np->name = __of_get_property(np, "name", NULL) ? : "<NULL>";
106 np->type = __of_get_property(np, "device_type", NULL) ? : "<NULL>";
108 phandle = __of_get_property(np, "phandle", &sz);
110 phandle = __of_get_property(np, "linux,phandle", &sz);
111 if (IS_ENABLED(PPC_PSERIES) && !phandle)
112 phandle = __of_get_property(np, "ibm,phandle", &sz);
113 np->phandle = (phandle && (sz >= 4)) ? be32_to_cpup(phandle) : 0;
116 np->sibling = np->parent->child;
117 np->allnext = np->parent->allnext;
118 np->parent->allnext = np;
119 np->parent->child = np;
120 of_node_clear_flag(np, OF_DETACHED);
124 * of_attach_node() - Plug a device node into the tree and global list.
126 int of_attach_node(struct device_node *np)
130 mutex_lock(&of_mutex);
131 raw_spin_lock_irqsave(&devtree_lock, flags);
132 __of_attach_node(np);
133 raw_spin_unlock_irqrestore(&devtree_lock, flags);
135 __of_attach_node_sysfs(np);
136 mutex_unlock(&of_mutex);
138 of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, np);
143 void __of_detach_node(struct device_node *np)
145 struct device_node *parent;
147 if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
151 if (WARN_ON(!parent))
154 if (of_allnodes == np)
155 of_allnodes = np->allnext;
157 struct device_node *prev;
158 for (prev = of_allnodes;
160 prev = prev->allnext)
162 prev->allnext = np->allnext;
165 if (parent->child == np)
166 parent->child = np->sibling;
168 struct device_node *prevsib;
169 for (prevsib = np->parent->child;
170 prevsib->sibling != np;
171 prevsib = prevsib->sibling)
173 prevsib->sibling = np->sibling;
176 of_node_set_flag(np, OF_DETACHED);
180 * of_detach_node() - "Unplug" a node from the device tree.
182 * The caller must hold a reference to the node. The memory associated with
183 * the node is not freed until its refcount goes to zero.
185 int of_detach_node(struct device_node *np)
190 mutex_lock(&of_mutex);
191 raw_spin_lock_irqsave(&devtree_lock, flags);
192 __of_detach_node(np);
193 raw_spin_unlock_irqrestore(&devtree_lock, flags);
195 __of_detach_node_sysfs(np);
196 mutex_unlock(&of_mutex);
198 of_reconfig_notify(OF_RECONFIG_DETACH_NODE, np);
204 * of_node_release() - release a dynamically allocated node
205 * @kref: kref element of the node to be released
207 * In of_node_put() this function is passed to kref_put() as the destructor.
209 void of_node_release(struct kobject *kobj)
211 struct device_node *node = kobj_to_device_node(kobj);
212 struct property *prop = node->properties;
214 /* We should never be releasing nodes that haven't been detached. */
215 if (!of_node_check_flag(node, OF_DETACHED)) {
216 pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name);
221 if (!of_node_check_flag(node, OF_DYNAMIC))
225 struct property *next = prop->next;
232 prop = node->deadprops;
233 node->deadprops = NULL;
236 kfree(node->full_name);
242 * __of_prop_dup - Copy a property dynamically.
243 * @prop: Property to copy
244 * @allocflags: Allocation flags (typically pass GFP_KERNEL)
246 * Copy a property by dynamically allocating the memory of both the
247 * property stucture and the property name & contents. The property's
248 * flags have the OF_DYNAMIC bit set so that we can differentiate between
249 * dynamically allocated properties and not.
250 * Returns the newly allocated property or NULL on out of memory error.
252 struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
254 struct property *new;
256 new = kzalloc(sizeof(*new), allocflags);
261 * NOTE: There is no check for zero length value.
262 * In case of a boolean property, this will allocate a value
263 * of zero bytes. We do this to work around the use
264 * of of_get_property() calls on boolean values.
266 new->name = kstrdup(prop->name, allocflags);
267 new->value = kmemdup(prop->value, prop->length, allocflags);
268 new->length = prop->length;
269 if (!new->name || !new->value)
272 /* mark the property as dynamic */
273 of_property_set_flag(new, OF_DYNAMIC);
285 * __of_node_alloc() - Create an empty device node dynamically.
286 * @full_name: Full name of the new device node
287 * @allocflags: Allocation flags (typically pass GFP_KERNEL)
289 * Create an empty device tree node, suitable for further modification.
290 * The node data are dynamically allocated and all the node flags
291 * have the OF_DYNAMIC & OF_DETACHED bits set.
292 * Returns the newly allocated node or NULL on out of memory error.
294 struct device_node *__of_node_alloc(const char *full_name, gfp_t allocflags)
296 struct device_node *node;
298 node = kzalloc(sizeof(*node), allocflags);
302 node->full_name = kstrdup(full_name, allocflags);
303 of_node_set_flag(node, OF_DYNAMIC);
304 of_node_set_flag(node, OF_DETACHED);
305 if (!node->full_name)
313 kfree(node->full_name);
318 static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
326 static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
328 switch (ce->action) {
329 case OF_RECONFIG_ADD_PROPERTY:
330 pr_debug("%p: %s %s/%s\n",
331 ce, "ADD_PROPERTY ", ce->np->full_name,
334 case OF_RECONFIG_REMOVE_PROPERTY:
335 pr_debug("%p: %s %s/%s\n",
336 ce, "REMOVE_PROPERTY", ce->np->full_name,
339 case OF_RECONFIG_UPDATE_PROPERTY:
340 pr_debug("%p: %s %s/%s\n",
341 ce, "UPDATE_PROPERTY", ce->np->full_name,
344 case OF_RECONFIG_ATTACH_NODE:
345 pr_debug("%p: %s %s\n",
346 ce, "ATTACH_NODE ", ce->np->full_name);
348 case OF_RECONFIG_DETACH_NODE:
349 pr_debug("%p: %s %s\n",
350 ce, "DETACH_NODE ", ce->np->full_name);
355 static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
361 static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
362 struct of_changeset_entry *rce)
364 memcpy(rce, ce, sizeof(*rce));
366 switch (ce->action) {
367 case OF_RECONFIG_ATTACH_NODE:
368 rce->action = OF_RECONFIG_DETACH_NODE;
370 case OF_RECONFIG_DETACH_NODE:
371 rce->action = OF_RECONFIG_ATTACH_NODE;
373 case OF_RECONFIG_ADD_PROPERTY:
374 rce->action = OF_RECONFIG_REMOVE_PROPERTY;
376 case OF_RECONFIG_REMOVE_PROPERTY:
377 rce->action = OF_RECONFIG_ADD_PROPERTY;
379 case OF_RECONFIG_UPDATE_PROPERTY:
380 rce->old_prop = ce->prop;
381 rce->prop = ce->old_prop;
386 static void __of_changeset_entry_notify(struct of_changeset_entry *ce, bool revert)
388 struct of_changeset_entry ce_inverted;
392 __of_changeset_entry_invert(ce, &ce_inverted);
396 switch (ce->action) {
397 case OF_RECONFIG_ATTACH_NODE:
398 case OF_RECONFIG_DETACH_NODE:
399 ret = of_reconfig_notify(ce->action, ce->np);
401 case OF_RECONFIG_ADD_PROPERTY:
402 case OF_RECONFIG_REMOVE_PROPERTY:
403 case OF_RECONFIG_UPDATE_PROPERTY:
404 ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
407 pr_err("%s: invalid devicetree changeset action: %i\n", __func__,
413 pr_err("%s: notifier error @%s\n", __func__, ce->np->full_name);
416 static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
418 struct property *old_prop, **propp;
422 __of_changeset_entry_dump(ce);
424 raw_spin_lock_irqsave(&devtree_lock, flags);
425 switch (ce->action) {
426 case OF_RECONFIG_ATTACH_NODE:
427 __of_attach_node(ce->np);
429 case OF_RECONFIG_DETACH_NODE:
430 __of_detach_node(ce->np);
432 case OF_RECONFIG_ADD_PROPERTY:
433 /* If the property is in deadprops then it must be removed */
434 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
435 if (*propp == ce->prop) {
436 *propp = ce->prop->next;
437 ce->prop->next = NULL;
442 ret = __of_add_property(ce->np, ce->prop);
444 pr_err("%s: add_property failed @%s/%s\n",
445 __func__, ce->np->full_name,
450 case OF_RECONFIG_REMOVE_PROPERTY:
451 ret = __of_remove_property(ce->np, ce->prop);
453 pr_err("%s: remove_property failed @%s/%s\n",
454 __func__, ce->np->full_name,
460 case OF_RECONFIG_UPDATE_PROPERTY:
461 /* If the property is in deadprops then it must be removed */
462 for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
463 if (*propp == ce->prop) {
464 *propp = ce->prop->next;
465 ce->prop->next = NULL;
470 ret = __of_update_property(ce->np, ce->prop, &old_prop);
472 pr_err("%s: update_property failed @%s/%s\n",
473 __func__, ce->np->full_name,
481 raw_spin_unlock_irqrestore(&devtree_lock, flags);
486 switch (ce->action) {
487 case OF_RECONFIG_ATTACH_NODE:
488 __of_attach_node_sysfs(ce->np);
490 case OF_RECONFIG_DETACH_NODE:
491 __of_detach_node_sysfs(ce->np);
493 case OF_RECONFIG_ADD_PROPERTY:
494 /* ignore duplicate names */
495 __of_add_property_sysfs(ce->np, ce->prop);
497 case OF_RECONFIG_REMOVE_PROPERTY:
498 __of_remove_property_sysfs(ce->np, ce->prop);
500 case OF_RECONFIG_UPDATE_PROPERTY:
501 __of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
508 static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
510 struct of_changeset_entry ce_inverted;
512 __of_changeset_entry_invert(ce, &ce_inverted);
513 return __of_changeset_entry_apply(&ce_inverted);
517 * of_changeset_init - Initialize a changeset for use
519 * @ocs: changeset pointer
521 * Initialize a changeset structure
523 void of_changeset_init(struct of_changeset *ocs)
525 memset(ocs, 0, sizeof(*ocs));
526 INIT_LIST_HEAD(&ocs->entries);
530 * of_changeset_destroy - Destroy a changeset
532 * @ocs: changeset pointer
534 * Destroys a changeset. Note that if a changeset is applied,
535 * its changes to the tree cannot be reverted.
537 void of_changeset_destroy(struct of_changeset *ocs)
539 struct of_changeset_entry *ce, *cen;
541 list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
542 __of_changeset_entry_destroy(ce);
546 * of_changeset_apply - Applies a changeset
548 * @ocs: changeset pointer
550 * Applies a changeset to the live tree.
551 * Any side-effects of live tree state changes are applied here on
552 * sucess, like creation/destruction of devices and side-effects
553 * like creation of sysfs properties and directories.
554 * Returns 0 on success, a negative error value in case of an error.
555 * On error the partially applied effects are reverted.
557 int of_changeset_apply(struct of_changeset *ocs)
559 struct of_changeset_entry *ce;
562 /* perform the rest of the work */
563 pr_debug("of_changeset: applying...\n");
564 list_for_each_entry(ce, &ocs->entries, node) {
565 ret = __of_changeset_entry_apply(ce);
567 pr_err("%s: Error applying changeset (%d)\n", __func__, ret);
568 list_for_each_entry_continue_reverse(ce, &ocs->entries, node)
569 __of_changeset_entry_revert(ce);
573 pr_debug("of_changeset: applied, emitting notifiers.\n");
575 /* drop the global lock while emitting notifiers */
576 mutex_unlock(&of_mutex);
577 list_for_each_entry(ce, &ocs->entries, node)
578 __of_changeset_entry_notify(ce, 0);
579 mutex_lock(&of_mutex);
580 pr_debug("of_changeset: notifiers sent.\n");
586 * of_changeset_revert - Reverts an applied changeset
588 * @ocs: changeset pointer
590 * Reverts a changeset returning the state of the tree to what it
591 * was before the application.
592 * Any side-effects like creation/destruction of devices and
593 * removal of sysfs properties and directories are applied.
594 * Returns 0 on success, a negative error value in case of an error.
596 int of_changeset_revert(struct of_changeset *ocs)
598 struct of_changeset_entry *ce;
601 pr_debug("of_changeset: reverting...\n");
602 list_for_each_entry_reverse(ce, &ocs->entries, node) {
603 ret = __of_changeset_entry_revert(ce);
605 pr_err("%s: Error reverting changeset (%d)\n", __func__, ret);
606 list_for_each_entry_continue(ce, &ocs->entries, node)
607 __of_changeset_entry_apply(ce);
611 pr_debug("of_changeset: reverted, emitting notifiers.\n");
613 /* drop the global lock while emitting notifiers */
614 mutex_unlock(&of_mutex);
615 list_for_each_entry_reverse(ce, &ocs->entries, node)
616 __of_changeset_entry_notify(ce, 1);
617 mutex_lock(&of_mutex);
618 pr_debug("of_changeset: notifiers sent.\n");
624 * of_changeset_action - Perform a changeset action
626 * @ocs: changeset pointer
627 * @action: action to perform
628 * @np: Pointer to device node
629 * @prop: Pointer to property
631 * On action being one of:
632 * + OF_RECONFIG_ATTACH_NODE
633 * + OF_RECONFIG_DETACH_NODE,
634 * + OF_RECONFIG_ADD_PROPERTY
635 * + OF_RECONFIG_REMOVE_PROPERTY,
636 * + OF_RECONFIG_UPDATE_PROPERTY
637 * Returns 0 on success, a negative error value in case of an error.
639 int of_changeset_action(struct of_changeset *ocs, unsigned long action,
640 struct device_node *np, struct property *prop)
642 struct of_changeset_entry *ce;
644 ce = kzalloc(sizeof(*ce), GFP_KERNEL);
646 pr_err("%s: Failed to allocate\n", __func__);
649 /* get a reference to the node */
651 ce->np = of_node_get(np);
654 if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
655 ce->old_prop = of_find_property(np, prop->name, NULL);
657 /* add it to the list */
658 list_add_tail(&ce->node, &ocs->entries);