2 * Procedures for creating, accessing and interpreting the device tree.
4 * Paul Mackerras August 1996.
5 * Copyright (C) 1996-2005 Paul Mackerras.
7 * Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
8 * {engebret|bergner}@us.ibm.com
10 * Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
12 * Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License
17 * as published by the Free Software Foundation; either version
18 * 2 of the License, or (at your option) any later version.
20 #include <linux/ctype.h>
21 #include <linux/module.h>
23 #include <linux/spinlock.h>
24 #include <linux/slab.h>
25 #include <linux/proc_fs.h>
27 #include "of_private.h"
29 LIST_HEAD(aliases_lookup);
31 struct device_node *of_allnodes;
32 EXPORT_SYMBOL(of_allnodes);
33 struct device_node *of_chosen;
34 struct device_node *of_aliases;
36 DEFINE_MUTEX(of_aliases_mutex);
38 /* use when traversing tree through the allnext, child, sibling,
39 * or parent members of struct device_node.
41 DEFINE_RAW_SPINLOCK(devtree_lock);
43 int of_n_addr_cells(struct device_node *np)
50 ip = of_get_property(np, "#address-cells", NULL);
52 return be32_to_cpup(ip);
54 /* No #address-cells property for the root node */
55 return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
57 EXPORT_SYMBOL(of_n_addr_cells);
59 int of_n_size_cells(struct device_node *np)
66 ip = of_get_property(np, "#size-cells", NULL);
68 return be32_to_cpup(ip);
70 /* No #size-cells property for the root node */
71 return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
73 EXPORT_SYMBOL(of_n_size_cells);
75 #if defined(CONFIG_OF_DYNAMIC)
77 * of_node_get - Increment refcount of a node
78 * @node: Node to inc refcount, NULL is supported to
79 * simplify writing of callers
83 struct device_node *of_node_get(struct device_node *node)
86 kref_get(&node->kref);
89 EXPORT_SYMBOL(of_node_get);
91 static inline struct device_node *kref_to_device_node(struct kref *kref)
93 return container_of(kref, struct device_node, kref);
97 * of_node_release - release a dynamically allocated node
98 * @kref: kref element of the node to be released
100 * In of_node_put() this function is passed to kref_put()
103 static void of_node_release(struct kref *kref)
105 struct device_node *node = kref_to_device_node(kref);
106 struct property *prop = node->properties;
108 /* We should never be releasing nodes that haven't been detached. */
109 if (!of_node_check_flag(node, OF_DETACHED)) {
110 pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name);
112 kref_init(&node->kref);
116 if (!of_node_check_flag(node, OF_DYNAMIC))
120 struct property *next = prop->next;
127 prop = node->deadprops;
128 node->deadprops = NULL;
131 kfree(node->full_name);
137 * of_node_put - Decrement refcount of a node
138 * @node: Node to dec refcount, NULL is supported to
139 * simplify writing of callers
142 void of_node_put(struct device_node *node)
145 kref_put(&node->kref, of_node_release);
147 EXPORT_SYMBOL(of_node_put);
148 #endif /* CONFIG_OF_DYNAMIC */
150 static struct property *__of_find_property(const struct device_node *np,
151 const char *name, int *lenp)
158 for (pp = np->properties; pp; pp = pp->next) {
159 if (of_prop_cmp(pp->name, name) == 0) {
169 struct property *of_find_property(const struct device_node *np,
176 raw_spin_lock_irqsave(&devtree_lock, flags);
177 pp = __of_find_property(np, name, lenp);
178 raw_spin_unlock_irqrestore(&devtree_lock, flags);
182 EXPORT_SYMBOL(of_find_property);
185 * of_find_all_nodes - Get next node in global list
186 * @prev: Previous node or NULL to start iteration
187 * of_node_put() will be called on it
189 * Returns a node pointer with refcount incremented, use
190 * of_node_put() on it when done.
192 struct device_node *of_find_all_nodes(struct device_node *prev)
194 struct device_node *np;
196 raw_spin_lock(&devtree_lock);
197 np = prev ? prev->allnext : of_allnodes;
198 for (; np != NULL; np = np->allnext)
202 raw_spin_unlock(&devtree_lock);
205 EXPORT_SYMBOL(of_find_all_nodes);
208 * Find a property with a given name for a given node
209 * and return the value.
211 static const void *__of_get_property(const struct device_node *np,
212 const char *name, int *lenp)
214 struct property *pp = __of_find_property(np, name, lenp);
216 return pp ? pp->value : NULL;
220 * Find a property with a given name for a given node
221 * and return the value.
223 const void *of_get_property(const struct device_node *np, const char *name,
226 struct property *pp = of_find_property(np, name, lenp);
228 return pp ? pp->value : NULL;
230 EXPORT_SYMBOL(of_get_property);
232 /** Checks if the given "compat" string matches one of the strings in
233 * the device's "compatible" property
235 static int __of_device_is_compatible(const struct device_node *device,
241 cp = __of_get_property(device, "compatible", &cplen);
245 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
255 /** Checks if the given "compat" string matches one of the strings in
256 * the device's "compatible" property
258 int of_device_is_compatible(const struct device_node *device,
264 raw_spin_lock_irqsave(&devtree_lock, flags);
265 res = __of_device_is_compatible(device, compat);
266 raw_spin_unlock_irqrestore(&devtree_lock, flags);
269 EXPORT_SYMBOL(of_device_is_compatible);
272 * of_machine_is_compatible - Test root of device tree for a given compatible value
273 * @compat: compatible string to look for in root node's compatible property.
275 * Returns true if the root node has the given value in its
276 * compatible property.
278 int of_machine_is_compatible(const char *compat)
280 struct device_node *root;
283 root = of_find_node_by_path("/");
285 rc = of_device_is_compatible(root, compat);
290 EXPORT_SYMBOL(of_machine_is_compatible);
293 * __of_device_is_available - check if a device is available for use
295 * @device: Node to check for availability, with locks already held
297 * Returns 1 if the status property is absent or set to "okay" or "ok",
300 static int __of_device_is_available(const struct device_node *device)
305 status = __of_get_property(device, "status", &statlen);
310 if (!strcmp(status, "okay") || !strcmp(status, "ok"))
318 * of_device_is_available - check if a device is available for use
320 * @device: Node to check for availability
322 * Returns 1 if the status property is absent or set to "okay" or "ok",
325 int of_device_is_available(const struct device_node *device)
330 raw_spin_lock_irqsave(&devtree_lock, flags);
331 res = __of_device_is_available(device);
332 raw_spin_unlock_irqrestore(&devtree_lock, flags);
336 EXPORT_SYMBOL(of_device_is_available);
339 * of_get_parent - Get a node's parent if any
340 * @node: Node to get parent
342 * Returns a node pointer with refcount incremented, use
343 * of_node_put() on it when done.
345 struct device_node *of_get_parent(const struct device_node *node)
347 struct device_node *np;
353 raw_spin_lock_irqsave(&devtree_lock, flags);
354 np = of_node_get(node->parent);
355 raw_spin_unlock_irqrestore(&devtree_lock, flags);
358 EXPORT_SYMBOL(of_get_parent);
361 * of_get_next_parent - Iterate to a node's parent
362 * @node: Node to get parent of
364 * This is like of_get_parent() except that it drops the
365 * refcount on the passed node, making it suitable for iterating
366 * through a node's parents.
368 * Returns a node pointer with refcount incremented, use
369 * of_node_put() on it when done.
371 struct device_node *of_get_next_parent(struct device_node *node)
373 struct device_node *parent;
379 raw_spin_lock_irqsave(&devtree_lock, flags);
380 parent = of_node_get(node->parent);
382 raw_spin_unlock_irqrestore(&devtree_lock, flags);
387 * of_get_next_child - Iterate a node childs
389 * @prev: previous child of the parent node, or NULL to get first
391 * Returns a node pointer with refcount incremented, use
392 * of_node_put() on it when done.
394 struct device_node *of_get_next_child(const struct device_node *node,
395 struct device_node *prev)
397 struct device_node *next;
400 raw_spin_lock_irqsave(&devtree_lock, flags);
401 next = prev ? prev->sibling : node->child;
402 for (; next; next = next->sibling)
403 if (of_node_get(next))
406 raw_spin_unlock_irqrestore(&devtree_lock, flags);
409 EXPORT_SYMBOL(of_get_next_child);
412 * of_get_next_available_child - Find the next available child node
414 * @prev: previous child of the parent node, or NULL to get first
416 * This function is like of_get_next_child(), except that it
417 * automatically skips any disabled nodes (i.e. status = "disabled").
419 struct device_node *of_get_next_available_child(const struct device_node *node,
420 struct device_node *prev)
422 struct device_node *next;
424 raw_spin_lock(&devtree_lock);
425 next = prev ? prev->sibling : node->child;
426 for (; next; next = next->sibling) {
427 if (!__of_device_is_available(next))
429 if (of_node_get(next))
433 raw_spin_unlock(&devtree_lock);
436 EXPORT_SYMBOL(of_get_next_available_child);
439 * of_get_child_by_name - Find the child node by name for a given parent
441 * @name: child name to look for.
443 * This function looks for child node for given matching name
445 * Returns a node pointer if found, with refcount incremented, use
446 * of_node_put() on it when done.
447 * Returns NULL if node is not found.
449 struct device_node *of_get_child_by_name(const struct device_node *node,
452 struct device_node *child;
454 for_each_child_of_node(node, child)
455 if (child->name && (of_node_cmp(child->name, name) == 0))
459 EXPORT_SYMBOL(of_get_child_by_name);
462 * of_find_node_by_path - Find a node matching a full OF path
463 * @path: The full path to match
465 * Returns a node pointer with refcount incremented, use
466 * of_node_put() on it when done.
468 struct device_node *of_find_node_by_path(const char *path)
470 struct device_node *np = of_allnodes;
473 raw_spin_lock_irqsave(&devtree_lock, flags);
474 for (; np; np = np->allnext) {
475 if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
479 raw_spin_unlock_irqrestore(&devtree_lock, flags);
482 EXPORT_SYMBOL(of_find_node_by_path);
485 * of_find_node_by_name - Find a node by its "name" property
486 * @from: The node to start searching from or NULL, the node
487 * you pass will not be searched, only the next one
488 * will; typically, you pass what the previous call
489 * returned. of_node_put() will be called on it
490 * @name: The name string to match against
492 * Returns a node pointer with refcount incremented, use
493 * of_node_put() on it when done.
495 struct device_node *of_find_node_by_name(struct device_node *from,
498 struct device_node *np;
501 raw_spin_lock_irqsave(&devtree_lock, flags);
502 np = from ? from->allnext : of_allnodes;
503 for (; np; np = np->allnext)
504 if (np->name && (of_node_cmp(np->name, name) == 0)
508 raw_spin_unlock_irqrestore(&devtree_lock, flags);
511 EXPORT_SYMBOL(of_find_node_by_name);
514 * of_find_node_by_type - Find a node by its "device_type" property
515 * @from: The node to start searching from, or NULL to start searching
516 * the entire device tree. The node you pass will not be
517 * searched, only the next one will; typically, you pass
518 * what the previous call returned. of_node_put() will be
519 * called on from for you.
520 * @type: The type string to match against
522 * Returns a node pointer with refcount incremented, use
523 * of_node_put() on it when done.
525 struct device_node *of_find_node_by_type(struct device_node *from,
528 struct device_node *np;
531 raw_spin_lock_irqsave(&devtree_lock, flags);
532 np = from ? from->allnext : of_allnodes;
533 for (; np; np = np->allnext)
534 if (np->type && (of_node_cmp(np->type, type) == 0)
538 raw_spin_unlock_irqrestore(&devtree_lock, flags);
541 EXPORT_SYMBOL(of_find_node_by_type);
544 * of_find_compatible_node - Find a node based on type and one of the
545 * tokens in its "compatible" property
546 * @from: The node to start searching from or NULL, the node
547 * you pass will not be searched, only the next one
548 * will; typically, you pass what the previous call
549 * returned. of_node_put() will be called on it
550 * @type: The type string to match "device_type" or NULL to ignore
551 * @compatible: The string to match to one of the tokens in the device
554 * Returns a node pointer with refcount incremented, use
555 * of_node_put() on it when done.
557 struct device_node *of_find_compatible_node(struct device_node *from,
558 const char *type, const char *compatible)
560 struct device_node *np;
563 raw_spin_lock_irqsave(&devtree_lock, flags);
564 np = from ? from->allnext : of_allnodes;
565 for (; np; np = np->allnext) {
567 && !(np->type && (of_node_cmp(np->type, type) == 0)))
569 if (__of_device_is_compatible(np, compatible) &&
574 raw_spin_unlock_irqrestore(&devtree_lock, flags);
577 EXPORT_SYMBOL(of_find_compatible_node);
580 * of_find_node_with_property - Find a node which has a property with
582 * @from: The node to start searching from or NULL, the node
583 * you pass will not be searched, only the next one
584 * will; typically, you pass what the previous call
585 * returned. of_node_put() will be called on it
586 * @prop_name: The name of the property to look for.
588 * Returns a node pointer with refcount incremented, use
589 * of_node_put() on it when done.
591 struct device_node *of_find_node_with_property(struct device_node *from,
592 const char *prop_name)
594 struct device_node *np;
598 raw_spin_lock_irqsave(&devtree_lock, flags);
599 np = from ? from->allnext : of_allnodes;
600 for (; np; np = np->allnext) {
601 for (pp = np->properties; pp; pp = pp->next) {
602 if (of_prop_cmp(pp->name, prop_name) == 0) {
610 raw_spin_unlock_irqrestore(&devtree_lock, flags);
613 EXPORT_SYMBOL(of_find_node_with_property);
616 const struct of_device_id *__of_match_node(const struct of_device_id *matches,
617 const struct device_node *node)
622 while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
624 if (matches->name[0])
626 && !strcmp(matches->name, node->name);
627 if (matches->type[0])
629 && !strcmp(matches->type, node->type);
630 if (matches->compatible[0])
631 match &= __of_device_is_compatible(node,
632 matches->compatible);
641 * of_match_node - Tell if an device_node has a matching of_match structure
642 * @matches: array of of device match structures to search in
643 * @node: the of device structure to match against
645 * Low level utility function used by device matching.
647 const struct of_device_id *of_match_node(const struct of_device_id *matches,
648 const struct device_node *node)
650 const struct of_device_id *match;
653 raw_spin_lock_irqsave(&devtree_lock, flags);
654 match = __of_match_node(matches, node);
655 raw_spin_unlock_irqrestore(&devtree_lock, flags);
658 EXPORT_SYMBOL(of_match_node);
661 * of_find_matching_node_and_match - Find a node based on an of_device_id
663 * @from: The node to start searching from or NULL, the node
664 * you pass will not be searched, only the next one
665 * will; typically, you pass what the previous call
666 * returned. of_node_put() will be called on it
667 * @matches: array of of device match structures to search in
668 * @match Updated to point at the matches entry which matched
670 * Returns a node pointer with refcount incremented, use
671 * of_node_put() on it when done.
673 struct device_node *of_find_matching_node_and_match(struct device_node *from,
674 const struct of_device_id *matches,
675 const struct of_device_id **match)
677 struct device_node *np;
678 const struct of_device_id *m;
684 raw_spin_lock_irqsave(&devtree_lock, flags);
685 np = from ? from->allnext : of_allnodes;
686 for (; np; np = np->allnext) {
687 m = __of_match_node(matches, np);
688 if (m && of_node_get(np)) {
695 raw_spin_unlock_irqrestore(&devtree_lock, flags);
698 EXPORT_SYMBOL(of_find_matching_node_and_match);
701 * of_modalias_node - Lookup appropriate modalias for a device node
702 * @node: pointer to a device tree node
703 * @modalias: Pointer to buffer that modalias value will be copied into
704 * @len: Length of modalias value
706 * Based on the value of the compatible property, this routine will attempt
707 * to choose an appropriate modalias value for a particular device tree node.
708 * It does this by stripping the manufacturer prefix (as delimited by a ',')
709 * from the first entry in the compatible list property.
711 * This routine returns 0 on success, <0 on failure.
713 int of_modalias_node(struct device_node *node, char *modalias, int len)
715 const char *compatible, *p;
718 compatible = of_get_property(node, "compatible", &cplen);
719 if (!compatible || strlen(compatible) > cplen)
721 p = strchr(compatible, ',');
722 strlcpy(modalias, p ? p + 1 : compatible, len);
725 EXPORT_SYMBOL_GPL(of_modalias_node);
728 * of_find_node_by_phandle - Find a node given a phandle
729 * @handle: phandle of the node to find
731 * Returns a node pointer with refcount incremented, use
732 * of_node_put() on it when done.
734 struct device_node *of_find_node_by_phandle(phandle handle)
736 struct device_node *np;
738 raw_spin_lock(&devtree_lock);
739 for (np = of_allnodes; np; np = np->allnext)
740 if (np->phandle == handle)
743 raw_spin_unlock(&devtree_lock);
746 EXPORT_SYMBOL(of_find_node_by_phandle);
749 * of_property_read_u32_index - Find and read a u32 from a multi-value property.
751 * @np: device node from which the property value is to be read.
752 * @propname: name of the property to be searched.
753 * @index: index of the u32 in the list of values
754 * @out_value: pointer to return value, modified only if no error.
756 * Search for a property in a device node and read nth 32-bit value from
757 * it. Returns 0 on success, -EINVAL if the property does not exist,
758 * -ENODATA if property does not have a value, and -EOVERFLOW if the
759 * property data isn't large enough.
761 * The out_value is modified only if a valid u32 value can be decoded.
763 int of_property_read_u32_index(const struct device_node *np,
764 const char *propname,
765 u32 index, u32 *out_value)
767 struct property *prop = of_find_property(np, propname, NULL);
773 if (((index + 1) * sizeof(*out_value)) > prop->length)
776 *out_value = be32_to_cpup(((__be32 *)prop->value) + index);
779 EXPORT_SYMBOL_GPL(of_property_read_u32_index);
782 * of_property_read_u8_array - Find and read an array of u8 from a property.
784 * @np: device node from which the property value is to be read.
785 * @propname: name of the property to be searched.
786 * @out_value: pointer to return value, modified only if return value is 0.
787 * @sz: number of array elements to read
789 * Search for a property in a device node and read 8-bit value(s) from
790 * it. Returns 0 on success, -EINVAL if the property does not exist,
791 * -ENODATA if property does not have a value, and -EOVERFLOW if the
792 * property data isn't large enough.
794 * dts entry of array should be like:
795 * property = /bits/ 8 <0x50 0x60 0x70>;
797 * The out_value is modified only if a valid u8 value can be decoded.
799 int of_property_read_u8_array(const struct device_node *np,
800 const char *propname, u8 *out_values, size_t sz)
802 struct property *prop = of_find_property(np, propname, NULL);
809 if ((sz * sizeof(*out_values)) > prop->length)
814 *out_values++ = *val++;
817 EXPORT_SYMBOL_GPL(of_property_read_u8_array);
820 * of_property_read_u16_array - Find and read an array of u16 from a property.
822 * @np: device node from which the property value is to be read.
823 * @propname: name of the property to be searched.
824 * @out_value: pointer to return value, modified only if return value is 0.
825 * @sz: number of array elements to read
827 * Search for a property in a device node and read 16-bit value(s) from
828 * it. Returns 0 on success, -EINVAL if the property does not exist,
829 * -ENODATA if property does not have a value, and -EOVERFLOW if the
830 * property data isn't large enough.
832 * dts entry of array should be like:
833 * property = /bits/ 16 <0x5000 0x6000 0x7000>;
835 * The out_value is modified only if a valid u16 value can be decoded.
837 int of_property_read_u16_array(const struct device_node *np,
838 const char *propname, u16 *out_values, size_t sz)
840 struct property *prop = of_find_property(np, propname, NULL);
847 if ((sz * sizeof(*out_values)) > prop->length)
852 *out_values++ = be16_to_cpup(val++);
855 EXPORT_SYMBOL_GPL(of_property_read_u16_array);
858 * of_property_read_u32_array - Find and read an array of 32 bit integers
861 * @np: device node from which the property value is to be read.
862 * @propname: name of the property to be searched.
863 * @out_value: pointer to return value, modified only if return value is 0.
864 * @sz: number of array elements to read
866 * Search for a property in a device node and read 32-bit value(s) from
867 * it. Returns 0 on success, -EINVAL if the property does not exist,
868 * -ENODATA if property does not have a value, and -EOVERFLOW if the
869 * property data isn't large enough.
871 * The out_value is modified only if a valid u32 value can be decoded.
873 int of_property_read_u32_array(const struct device_node *np,
874 const char *propname, u32 *out_values,
877 struct property *prop = of_find_property(np, propname, NULL);
884 if ((sz * sizeof(*out_values)) > prop->length)
889 *out_values++ = be32_to_cpup(val++);
892 EXPORT_SYMBOL_GPL(of_property_read_u32_array);
895 * of_property_read_u64 - Find and read a 64 bit integer from a property
896 * @np: device node from which the property value is to be read.
897 * @propname: name of the property to be searched.
898 * @out_value: pointer to return value, modified only if return value is 0.
900 * Search for a property in a device node and read a 64-bit value from
901 * it. Returns 0 on success, -EINVAL if the property does not exist,
902 * -ENODATA if property does not have a value, and -EOVERFLOW if the
903 * property data isn't large enough.
905 * The out_value is modified only if a valid u64 value can be decoded.
907 int of_property_read_u64(const struct device_node *np, const char *propname,
910 struct property *prop = of_find_property(np, propname, NULL);
916 if (sizeof(*out_value) > prop->length)
918 *out_value = of_read_number(prop->value, 2);
921 EXPORT_SYMBOL_GPL(of_property_read_u64);
924 * of_property_read_string - Find and read a string from a property
925 * @np: device node from which the property value is to be read.
926 * @propname: name of the property to be searched.
927 * @out_string: pointer to null terminated return string, modified only if
930 * Search for a property in a device tree node and retrieve a null
931 * terminated string value (pointer to data, not a copy). Returns 0 on
932 * success, -EINVAL if the property does not exist, -ENODATA if property
933 * does not have a value, and -EILSEQ if the string is not null-terminated
934 * within the length of the property data.
936 * The out_string pointer is modified only if a valid string can be decoded.
938 int of_property_read_string(struct device_node *np, const char *propname,
939 const char **out_string)
941 struct property *prop = of_find_property(np, propname, NULL);
946 if (strnlen(prop->value, prop->length) >= prop->length)
948 *out_string = prop->value;
951 EXPORT_SYMBOL_GPL(of_property_read_string);
954 * of_property_read_string_index - Find and read a string from a multiple
956 * @np: device node from which the property value is to be read.
957 * @propname: name of the property to be searched.
958 * @index: index of the string in the list of strings
959 * @out_string: pointer to null terminated return string, modified only if
962 * Search for a property in a device tree node and retrieve a null
963 * terminated string value (pointer to data, not a copy) in the list of strings
964 * contained in that property.
965 * Returns 0 on success, -EINVAL if the property does not exist, -ENODATA if
966 * property does not have a value, and -EILSEQ if the string is not
967 * null-terminated within the length of the property data.
969 * The out_string pointer is modified only if a valid string can be decoded.
971 int of_property_read_string_index(struct device_node *np, const char *propname,
972 int index, const char **output)
974 struct property *prop = of_find_property(np, propname, NULL);
976 size_t l = 0, total = 0;
983 if (strnlen(prop->value, prop->length) >= prop->length)
988 for (i = 0; total < prop->length; total += l, p += l) {
997 EXPORT_SYMBOL_GPL(of_property_read_string_index);
1000 * of_property_match_string() - Find string in a list and return index
1001 * @np: pointer to node containing string list property
1002 * @propname: string list property name
1003 * @string: pointer to string to search for in string list
1005 * This function searches a string list property and returns the index
1006 * of a specific string value.
1008 int of_property_match_string(struct device_node *np, const char *propname,
1011 struct property *prop = of_find_property(np, propname, NULL);
1014 const char *p, *end;
1022 end = p + prop->length;
1024 for (i = 0; p < end; i++, p += l) {
1028 pr_debug("comparing %s with %s\n", string, p);
1029 if (strcmp(string, p) == 0)
1030 return i; /* Found it; return index */
1034 EXPORT_SYMBOL_GPL(of_property_match_string);
1037 * of_property_count_strings - Find and return the number of strings from a
1038 * multiple strings property.
1039 * @np: device node from which the property value is to be read.
1040 * @propname: name of the property to be searched.
1042 * Search for a property in a device tree node and retrieve the number of null
1043 * terminated string contain in it. Returns the number of strings on
1044 * success, -EINVAL if the property does not exist, -ENODATA if property
1045 * does not have a value, and -EILSEQ if the string is not null-terminated
1046 * within the length of the property data.
1048 int of_property_count_strings(struct device_node *np, const char *propname)
1050 struct property *prop = of_find_property(np, propname, NULL);
1052 size_t l = 0, total = 0;
1059 if (strnlen(prop->value, prop->length) >= prop->length)
1064 for (i = 0; total < prop->length; total += l, p += l, i++)
1069 EXPORT_SYMBOL_GPL(of_property_count_strings);
1072 * of_parse_phandle - Resolve a phandle property to a device_node pointer
1073 * @np: Pointer to device node holding phandle property
1074 * @phandle_name: Name of property holding a phandle value
1075 * @index: For properties holding a table of phandles, this is the index into
1078 * Returns the device_node pointer with refcount incremented. Use
1079 * of_node_put() on it when done.
1081 struct device_node *of_parse_phandle(const struct device_node *np,
1082 const char *phandle_name, int index)
1084 const __be32 *phandle;
1087 phandle = of_get_property(np, phandle_name, &size);
1088 if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
1091 return of_find_node_by_phandle(be32_to_cpup(phandle + index));
1093 EXPORT_SYMBOL(of_parse_phandle);
1096 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
1097 * @np: pointer to a device tree node containing a list
1098 * @list_name: property name that contains a list
1099 * @cells_name: property name that specifies phandles' arguments count
1100 * @index: index of a phandle to parse out
1101 * @out_args: optional pointer to output arguments structure (will be filled)
1103 * This function is useful to parse lists of phandles and their arguments.
1104 * Returns 0 on success and fills out_args, on error returns appropriate
1107 * Caller is responsible to call of_node_put() on the returned out_args->node
1113 * #list-cells = <2>;
1117 * #list-cells = <1>;
1121 * list = <&phandle1 1 2 &phandle2 3>;
1124 * To get a device_node of the `node2' node you may call this:
1125 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
1127 static int __of_parse_phandle_with_args(const struct device_node *np,
1128 const char *list_name,
1129 const char *cells_name, int index,
1130 struct of_phandle_args *out_args)
1132 const __be32 *list, *list_end;
1133 int rc = 0, size, cur_index = 0;
1135 struct device_node *node = NULL;
1138 /* Retrieve the phandle list property */
1139 list = of_get_property(np, list_name, &size);
1142 list_end = list + size / sizeof(*list);
1144 /* Loop over the phandles until all the requested entry is found */
1145 while (list < list_end) {
1150 * If phandle is 0, then it is an empty entry with no
1151 * arguments. Skip forward to the next entry.
1153 phandle = be32_to_cpup(list++);
1156 * Find the provider node and parse the #*-cells
1157 * property to determine the argument length
1159 node = of_find_node_by_phandle(phandle);
1161 pr_err("%s: could not find phandle\n",
1165 if (of_property_read_u32(node, cells_name, &count)) {
1166 pr_err("%s: could not get %s for %s\n",
1167 np->full_name, cells_name,
1173 * Make sure that the arguments actually fit in the
1174 * remaining property data length
1176 if (list + count > list_end) {
1177 pr_err("%s: arguments longer than property\n",
1184 * All of the error cases above bail out of the loop, so at
1185 * this point, the parsing is successful. If the requested
1186 * index matches, then fill the out_args structure and return,
1187 * or return -ENOENT for an empty entry.
1190 if (cur_index == index) {
1196 if (WARN_ON(count > MAX_PHANDLE_ARGS))
1197 count = MAX_PHANDLE_ARGS;
1198 out_args->np = node;
1199 out_args->args_count = count;
1200 for (i = 0; i < count; i++)
1201 out_args->args[i] = be32_to_cpup(list++);
1204 /* Found it! return success */
1217 * Unlock node before returning result; will be one of:
1218 * -ENOENT : index is for empty phandle
1219 * -EINVAL : parsing error on data
1220 * [1..n] : Number of phandle (count mode; when index = -1)
1222 rc = index < 0 ? cur_index : -ENOENT;
1229 int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
1230 const char *cells_name, int index,
1231 struct of_phandle_args *out_args)
1235 return __of_parse_phandle_with_args(np, list_name, cells_name, index, out_args);
1237 EXPORT_SYMBOL(of_parse_phandle_with_args);
1240 * of_count_phandle_with_args() - Find the number of phandles references in a property
1241 * @np: pointer to a device tree node containing a list
1242 * @list_name: property name that contains a list
1243 * @cells_name: property name that specifies phandles' arguments count
1245 * Returns the number of phandle + argument tuples within a property. It
1246 * is a typical pattern to encode a list of phandle and variable
1247 * arguments into a single property. The number of arguments is encoded
1248 * by a property in the phandle-target node. For example, a gpios
1249 * property would contain a list of GPIO specifies consisting of a
1250 * phandle and 1 or more arguments. The number of arguments are
1251 * determined by the #gpio-cells property in the node pointed to by the
1254 int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
1255 const char *cells_name)
1257 return __of_parse_phandle_with_args(np, list_name, cells_name, -1, NULL);
1259 EXPORT_SYMBOL(of_count_phandle_with_args);
1261 #if defined(CONFIG_OF_DYNAMIC)
1262 static int of_property_notify(int action, struct device_node *np,
1263 struct property *prop)
1265 struct of_prop_reconfig pr;
1269 return of_reconfig_notify(action, &pr);
1272 static int of_property_notify(int action, struct device_node *np,
1273 struct property *prop)
1280 * of_add_property - Add a property to a node
1282 int of_add_property(struct device_node *np, struct property *prop)
1284 struct property **next;
1285 unsigned long flags;
1288 rc = of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop);
1293 raw_spin_lock_irqsave(&devtree_lock, flags);
1294 next = &np->properties;
1296 if (strcmp(prop->name, (*next)->name) == 0) {
1297 /* duplicate ! don't insert it */
1298 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1301 next = &(*next)->next;
1304 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1306 #ifdef CONFIG_PROC_DEVICETREE
1307 /* try to add to proc as well if it was initialized */
1309 proc_device_tree_add_prop(np->pde, prop);
1310 #endif /* CONFIG_PROC_DEVICETREE */
1316 * of_remove_property - Remove a property from a node.
1318 * Note that we don't actually remove it, since we have given out
1319 * who-knows-how-many pointers to the data using get-property.
1320 * Instead we just move the property to the "dead properties"
1321 * list, so it won't be found any more.
1323 int of_remove_property(struct device_node *np, struct property *prop)
1325 struct property **next;
1326 unsigned long flags;
1330 rc = of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop);
1334 raw_spin_lock_irqsave(&devtree_lock, flags);
1335 next = &np->properties;
1337 if (*next == prop) {
1338 /* found the node */
1340 prop->next = np->deadprops;
1341 np->deadprops = prop;
1345 next = &(*next)->next;
1347 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1352 #ifdef CONFIG_PROC_DEVICETREE
1353 /* try to remove the proc node as well */
1355 proc_device_tree_remove_prop(np->pde, prop);
1356 #endif /* CONFIG_PROC_DEVICETREE */
1362 * of_update_property - Update a property in a node, if the property does
1363 * not exist, add it.
1365 * Note that we don't actually remove it, since we have given out
1366 * who-knows-how-many pointers to the data using get-property.
1367 * Instead we just move the property to the "dead properties" list,
1368 * and add the new property to the property list
1370 int of_update_property(struct device_node *np, struct property *newprop)
1372 struct property **next, *oldprop;
1373 unsigned long flags;
1376 rc = of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop);
1383 oldprop = of_find_property(np, newprop->name, NULL);
1385 return of_add_property(np, newprop);
1387 raw_spin_lock_irqsave(&devtree_lock, flags);
1388 next = &np->properties;
1390 if (*next == oldprop) {
1391 /* found the node */
1392 newprop->next = oldprop->next;
1394 oldprop->next = np->deadprops;
1395 np->deadprops = oldprop;
1399 next = &(*next)->next;
1401 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1406 #ifdef CONFIG_PROC_DEVICETREE
1407 /* try to add to proc as well if it was initialized */
1409 proc_device_tree_update_prop(np->pde, newprop, oldprop);
1410 #endif /* CONFIG_PROC_DEVICETREE */
1415 #if defined(CONFIG_OF_DYNAMIC)
1417 * Support for dynamic device trees.
1419 * On some platforms, the device tree can be manipulated at runtime.
1420 * The routines in this section support adding, removing and changing
1421 * device tree nodes.
1424 static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
1426 int of_reconfig_notifier_register(struct notifier_block *nb)
1428 return blocking_notifier_chain_register(&of_reconfig_chain, nb);
1430 EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
1432 int of_reconfig_notifier_unregister(struct notifier_block *nb)
1434 return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
1436 EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
1438 int of_reconfig_notify(unsigned long action, void *p)
1442 rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
1443 return notifier_to_errno(rc);
1446 #ifdef CONFIG_PROC_DEVICETREE
1447 static void of_add_proc_dt_entry(struct device_node *dn)
1449 struct proc_dir_entry *ent;
1451 ent = proc_mkdir(strrchr(dn->full_name, '/') + 1, dn->parent->pde);
1453 proc_device_tree_add_node(dn, ent);
1456 static void of_add_proc_dt_entry(struct device_node *dn)
1463 * of_attach_node - Plug a device node into the tree and global list.
1465 int of_attach_node(struct device_node *np)
1467 unsigned long flags;
1470 rc = of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, np);
1474 raw_spin_lock_irqsave(&devtree_lock, flags);
1475 np->sibling = np->parent->child;
1476 np->allnext = of_allnodes;
1477 np->parent->child = np;
1479 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1481 of_add_proc_dt_entry(np);
1485 #ifdef CONFIG_PROC_DEVICETREE
1486 static void of_remove_proc_dt_entry(struct device_node *dn)
1488 struct device_node *parent = dn->parent;
1489 struct property *prop = dn->properties;
1492 remove_proc_entry(prop->name, dn->pde);
1497 remove_proc_entry(dn->pde->name, parent->pde);
1500 static void of_remove_proc_dt_entry(struct device_node *dn)
1507 * of_detach_node - "Unplug" a node from the device tree.
1509 * The caller must hold a reference to the node. The memory associated with
1510 * the node is not freed until its refcount goes to zero.
1512 int of_detach_node(struct device_node *np)
1514 struct device_node *parent;
1515 unsigned long flags;
1518 rc = of_reconfig_notify(OF_RECONFIG_DETACH_NODE, np);
1522 raw_spin_lock_irqsave(&devtree_lock, flags);
1524 if (of_node_check_flag(np, OF_DETACHED)) {
1525 /* someone already detached it */
1526 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1530 parent = np->parent;
1532 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1536 if (of_allnodes == np)
1537 of_allnodes = np->allnext;
1539 struct device_node *prev;
1540 for (prev = of_allnodes;
1541 prev->allnext != np;
1542 prev = prev->allnext)
1544 prev->allnext = np->allnext;
1547 if (parent->child == np)
1548 parent->child = np->sibling;
1550 struct device_node *prevsib;
1551 for (prevsib = np->parent->child;
1552 prevsib->sibling != np;
1553 prevsib = prevsib->sibling)
1555 prevsib->sibling = np->sibling;
1558 of_node_set_flag(np, OF_DETACHED);
1559 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1561 of_remove_proc_dt_entry(np);
1564 #endif /* defined(CONFIG_OF_DYNAMIC) */
1566 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1567 int id, const char *stem, int stem_len)
1571 strncpy(ap->stem, stem, stem_len);
1572 ap->stem[stem_len] = 0;
1573 list_add_tail(&ap->link, &aliases_lookup);
1574 pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
1575 ap->alias, ap->stem, ap->id, of_node_full_name(np));
1579 * of_alias_scan - Scan all properties of 'aliases' node
1581 * The function scans all the properties of 'aliases' node and populate
1582 * the the global lookup table with the properties. It returns the
1583 * number of alias_prop found, or error code in error case.
1585 * @dt_alloc: An allocator that provides a virtual address to memory
1586 * for the resulting tree
1588 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1590 struct property *pp;
1592 of_chosen = of_find_node_by_path("/chosen");
1593 if (of_chosen == NULL)
1594 of_chosen = of_find_node_by_path("/chosen@0");
1595 of_aliases = of_find_node_by_path("/aliases");
1599 for_each_property_of_node(of_aliases, pp) {
1600 const char *start = pp->name;
1601 const char *end = start + strlen(start);
1602 struct device_node *np;
1603 struct alias_prop *ap;
1606 /* Skip those we do not want to proceed */
1607 if (!strcmp(pp->name, "name") ||
1608 !strcmp(pp->name, "phandle") ||
1609 !strcmp(pp->name, "linux,phandle"))
1612 np = of_find_node_by_path(pp->value);
1616 /* walk the alias backwards to extract the id and work out
1617 * the 'stem' string */
1618 while (isdigit(*(end-1)) && end > start)
1622 if (kstrtoint(end, 10, &id) < 0)
1625 /* Allocate an alias_prop with enough space for the stem */
1626 ap = dt_alloc(sizeof(*ap) + len + 1, 4);
1630 of_alias_add(ap, np, id, start, len);
1635 * of_alias_get_id - Get alias id for the given device_node
1636 * @np: Pointer to the given device_node
1637 * @stem: Alias stem of the given device_node
1639 * The function travels the lookup table to get alias id for the given
1640 * device_node and alias stem. It returns the alias id if find it.
1642 int of_alias_get_id(struct device_node *np, const char *stem)
1644 struct alias_prop *app;
1647 mutex_lock(&of_aliases_mutex);
1648 list_for_each_entry(app, &aliases_lookup, link) {
1649 if (strcmp(app->stem, stem) != 0)
1652 if (np == app->np) {
1657 mutex_unlock(&of_aliases_mutex);
1661 EXPORT_SYMBOL_GPL(of_alias_get_id);
1663 const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
1666 const void *curv = cur;
1676 curv += sizeof(*cur);
1677 if (curv >= prop->value + prop->length)
1681 *pu = be32_to_cpup(curv);
1684 EXPORT_SYMBOL_GPL(of_prop_next_u32);
1686 const char *of_prop_next_string(struct property *prop, const char *cur)
1688 const void *curv = cur;
1696 curv += strlen(cur) + 1;
1697 if (curv >= prop->value + prop->length)
1702 EXPORT_SYMBOL_GPL(of_prop_next_string);