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>
28 * struct alias_prop - Alias property in 'aliases' node
29 * @link: List node to link the structure in aliases_lookup list
30 * @alias: Alias property name
31 * @np: Pointer to device_node that the alias stands for
32 * @id: Index value from end of alias name
33 * @stem: Alias string without the index
35 * The structure represents one alias property of 'aliases' node as
36 * an entry in aliases_lookup list.
39 struct list_head link;
41 struct device_node *np;
46 static LIST_HEAD(aliases_lookup);
48 struct device_node *allnodes;
49 struct device_node *of_chosen;
50 struct device_node *of_aliases;
52 static DEFINE_MUTEX(of_aliases_mutex);
54 /* use when traversing tree through the allnext, child, sibling,
55 * or parent members of struct device_node.
57 DEFINE_RWLOCK(devtree_lock);
59 int of_n_addr_cells(struct device_node *np)
66 ip = of_get_property(np, "#address-cells", NULL);
68 return be32_to_cpup(ip);
70 /* No #address-cells property for the root node */
71 return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
73 EXPORT_SYMBOL(of_n_addr_cells);
75 int of_n_size_cells(struct device_node *np)
82 ip = of_get_property(np, "#size-cells", NULL);
84 return be32_to_cpup(ip);
86 /* No #size-cells property for the root node */
87 return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
89 EXPORT_SYMBOL(of_n_size_cells);
91 #if defined(CONFIG_OF_DYNAMIC)
93 * of_node_get - Increment refcount of a node
94 * @node: Node to inc refcount, NULL is supported to
95 * simplify writing of callers
99 struct device_node *of_node_get(struct device_node *node)
102 kref_get(&node->kref);
105 EXPORT_SYMBOL(of_node_get);
107 static inline struct device_node *kref_to_device_node(struct kref *kref)
109 return container_of(kref, struct device_node, kref);
113 * of_node_release - release a dynamically allocated node
114 * @kref: kref element of the node to be released
116 * In of_node_put() this function is passed to kref_put()
119 static void of_node_release(struct kref *kref)
121 struct device_node *node = kref_to_device_node(kref);
122 struct property *prop = node->properties;
124 /* We should never be releasing nodes that haven't been detached. */
125 if (!of_node_check_flag(node, OF_DETACHED)) {
126 pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name);
128 kref_init(&node->kref);
132 if (!of_node_check_flag(node, OF_DYNAMIC))
136 struct property *next = prop->next;
143 prop = node->deadprops;
144 node->deadprops = NULL;
147 kfree(node->full_name);
153 * of_node_put - Decrement refcount of a node
154 * @node: Node to dec refcount, NULL is supported to
155 * simplify writing of callers
158 void of_node_put(struct device_node *node)
161 kref_put(&node->kref, of_node_release);
163 EXPORT_SYMBOL(of_node_put);
164 #endif /* CONFIG_OF_DYNAMIC */
166 struct property *of_find_property(const struct device_node *np,
175 read_lock(&devtree_lock);
176 for (pp = np->properties; pp; pp = pp->next) {
177 if (of_prop_cmp(pp->name, name) == 0) {
183 read_unlock(&devtree_lock);
187 EXPORT_SYMBOL(of_find_property);
190 * of_find_all_nodes - Get next node in global list
191 * @prev: Previous node or NULL to start iteration
192 * of_node_put() will be called on it
194 * Returns a node pointer with refcount incremented, use
195 * of_node_put() on it when done.
197 struct device_node *of_find_all_nodes(struct device_node *prev)
199 struct device_node *np;
201 read_lock(&devtree_lock);
202 np = prev ? prev->allnext : allnodes;
203 for (; np != NULL; np = np->allnext)
207 read_unlock(&devtree_lock);
210 EXPORT_SYMBOL(of_find_all_nodes);
213 * Find a property with a given name for a given node
214 * and return the value.
216 const void *of_get_property(const struct device_node *np, const char *name,
219 struct property *pp = of_find_property(np, name, lenp);
221 return pp ? pp->value : NULL;
223 EXPORT_SYMBOL(of_get_property);
225 /** Checks if the given "compat" string matches one of the strings in
226 * the device's "compatible" property
228 int of_device_is_compatible(const struct device_node *device,
234 cp = of_get_property(device, "compatible", &cplen);
238 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
247 EXPORT_SYMBOL(of_device_is_compatible);
250 * of_machine_is_compatible - Test root of device tree for a given compatible value
251 * @compat: compatible string to look for in root node's compatible property.
253 * Returns true if the root node has the given value in its
254 * compatible property.
256 int of_machine_is_compatible(const char *compat)
258 struct device_node *root;
261 root = of_find_node_by_path("/");
263 rc = of_device_is_compatible(root, compat);
268 EXPORT_SYMBOL(of_machine_is_compatible);
271 * of_device_is_available - check if a device is available for use
273 * @device: Node to check for availability
275 * Returns 1 if the status property is absent or set to "okay" or "ok",
278 int of_device_is_available(const struct device_node *device)
283 status = of_get_property(device, "status", &statlen);
288 if (!strcmp(status, "okay") || !strcmp(status, "ok"))
294 EXPORT_SYMBOL(of_device_is_available);
297 * of_get_parent - Get a node's parent if any
298 * @node: Node to get parent
300 * Returns a node pointer with refcount incremented, use
301 * of_node_put() on it when done.
303 struct device_node *of_get_parent(const struct device_node *node)
305 struct device_node *np;
310 read_lock(&devtree_lock);
311 np = of_node_get(node->parent);
312 read_unlock(&devtree_lock);
315 EXPORT_SYMBOL(of_get_parent);
318 * of_get_next_parent - Iterate to a node's parent
319 * @node: Node to get parent of
321 * This is like of_get_parent() except that it drops the
322 * refcount on the passed node, making it suitable for iterating
323 * through a node's parents.
325 * Returns a node pointer with refcount incremented, use
326 * of_node_put() on it when done.
328 struct device_node *of_get_next_parent(struct device_node *node)
330 struct device_node *parent;
335 read_lock(&devtree_lock);
336 parent = of_node_get(node->parent);
338 read_unlock(&devtree_lock);
343 * of_get_next_child - Iterate a node childs
345 * @prev: previous child of the parent node, or NULL to get first
347 * Returns a node pointer with refcount incremented, use
348 * of_node_put() on it when done.
350 struct device_node *of_get_next_child(const struct device_node *node,
351 struct device_node *prev)
353 struct device_node *next;
355 read_lock(&devtree_lock);
356 next = prev ? prev->sibling : node->child;
357 for (; next; next = next->sibling)
358 if (of_node_get(next))
361 read_unlock(&devtree_lock);
364 EXPORT_SYMBOL(of_get_next_child);
367 * of_get_next_available_child - Find the next available child node
369 * @prev: previous child of the parent node, or NULL to get first
371 * This function is like of_get_next_child(), except that it
372 * automatically skips any disabled nodes (i.e. status = "disabled").
374 struct device_node *of_get_next_available_child(const struct device_node *node,
375 struct device_node *prev)
377 struct device_node *next;
379 read_lock(&devtree_lock);
380 next = prev ? prev->sibling : node->child;
381 for (; next; next = next->sibling) {
382 if (!of_device_is_available(next))
384 if (of_node_get(next))
388 read_unlock(&devtree_lock);
391 EXPORT_SYMBOL(of_get_next_available_child);
394 * of_get_child_by_name - Find the child node by name for a given parent
396 * @name: child name to look for.
398 * This function looks for child node for given matching name
400 * Returns a node pointer if found, with refcount incremented, use
401 * of_node_put() on it when done.
402 * Returns NULL if node is not found.
404 struct device_node *of_get_child_by_name(const struct device_node *node,
407 struct device_node *child;
409 for_each_child_of_node(node, child)
410 if (child->name && (of_node_cmp(child->name, name) == 0))
414 EXPORT_SYMBOL(of_get_child_by_name);
417 * of_find_node_by_path - Find a node matching a full OF path
418 * @path: The full path to match
420 * Returns a node pointer with refcount incremented, use
421 * of_node_put() on it when done.
423 struct device_node *of_find_node_by_path(const char *path)
425 struct device_node *np = allnodes;
427 read_lock(&devtree_lock);
428 for (; np; np = np->allnext) {
429 if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
433 read_unlock(&devtree_lock);
436 EXPORT_SYMBOL(of_find_node_by_path);
439 * of_find_node_by_name - Find a node by its "name" property
440 * @from: The node to start searching from or NULL, the node
441 * you pass will not be searched, only the next one
442 * will; typically, you pass what the previous call
443 * returned. of_node_put() will be called on it
444 * @name: The name string to match against
446 * Returns a node pointer with refcount incremented, use
447 * of_node_put() on it when done.
449 struct device_node *of_find_node_by_name(struct device_node *from,
452 struct device_node *np;
454 read_lock(&devtree_lock);
455 np = from ? from->allnext : allnodes;
456 for (; np; np = np->allnext)
457 if (np->name && (of_node_cmp(np->name, name) == 0)
461 read_unlock(&devtree_lock);
464 EXPORT_SYMBOL(of_find_node_by_name);
467 * of_find_node_by_type - Find a node by its "device_type" property
468 * @from: The node to start searching from, or NULL to start searching
469 * the entire device tree. The node you pass will not be
470 * searched, only the next one will; typically, you pass
471 * what the previous call returned. of_node_put() will be
472 * called on from for you.
473 * @type: The type string to match against
475 * Returns a node pointer with refcount incremented, use
476 * of_node_put() on it when done.
478 struct device_node *of_find_node_by_type(struct device_node *from,
481 struct device_node *np;
483 read_lock(&devtree_lock);
484 np = from ? from->allnext : allnodes;
485 for (; np; np = np->allnext)
486 if (np->type && (of_node_cmp(np->type, type) == 0)
490 read_unlock(&devtree_lock);
493 EXPORT_SYMBOL(of_find_node_by_type);
496 * of_find_compatible_node - Find a node based on type and one of the
497 * tokens in its "compatible" property
498 * @from: The node to start searching from or NULL, the node
499 * you pass will not be searched, only the next one
500 * will; typically, you pass what the previous call
501 * returned. of_node_put() will be called on it
502 * @type: The type string to match "device_type" or NULL to ignore
503 * @compatible: The string to match to one of the tokens in the device
506 * Returns a node pointer with refcount incremented, use
507 * of_node_put() on it when done.
509 struct device_node *of_find_compatible_node(struct device_node *from,
510 const char *type, const char *compatible)
512 struct device_node *np;
514 read_lock(&devtree_lock);
515 np = from ? from->allnext : allnodes;
516 for (; np; np = np->allnext) {
518 && !(np->type && (of_node_cmp(np->type, type) == 0)))
520 if (of_device_is_compatible(np, compatible) && of_node_get(np))
524 read_unlock(&devtree_lock);
527 EXPORT_SYMBOL(of_find_compatible_node);
530 * of_find_node_with_property - Find a node which has a property with
532 * @from: The node to start searching from or NULL, the node
533 * you pass will not be searched, only the next one
534 * will; typically, you pass what the previous call
535 * returned. of_node_put() will be called on it
536 * @prop_name: The name of the property to look for.
538 * Returns a node pointer with refcount incremented, use
539 * of_node_put() on it when done.
541 struct device_node *of_find_node_with_property(struct device_node *from,
542 const char *prop_name)
544 struct device_node *np;
547 read_lock(&devtree_lock);
548 np = from ? from->allnext : allnodes;
549 for (; np; np = np->allnext) {
550 for (pp = np->properties; pp; pp = pp->next) {
551 if (of_prop_cmp(pp->name, prop_name) == 0) {
559 read_unlock(&devtree_lock);
562 EXPORT_SYMBOL(of_find_node_with_property);
565 * of_match_node - Tell if an device_node has a matching of_match structure
566 * @matches: array of of device match structures to search in
567 * @node: the of device structure to match against
569 * Low level utility function used by device matching.
571 const struct of_device_id *of_match_node(const struct of_device_id *matches,
572 const struct device_node *node)
577 while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
579 if (matches->name[0])
581 && !strcmp(matches->name, node->name);
582 if (matches->type[0])
584 && !strcmp(matches->type, node->type);
585 if (matches->compatible[0])
586 match &= of_device_is_compatible(node,
587 matches->compatible);
594 EXPORT_SYMBOL(of_match_node);
597 * of_find_matching_node_and_match - Find a node based on an of_device_id
599 * @from: The node to start searching from or NULL, the node
600 * you pass will not be searched, only the next one
601 * will; typically, you pass what the previous call
602 * returned. of_node_put() will be called on it
603 * @matches: array of of device match structures to search in
604 * @match Updated to point at the matches entry which matched
606 * Returns a node pointer with refcount incremented, use
607 * of_node_put() on it when done.
609 struct device_node *of_find_matching_node_and_match(struct device_node *from,
610 const struct of_device_id *matches,
611 const struct of_device_id **match)
613 struct device_node *np;
618 read_lock(&devtree_lock);
619 np = from ? from->allnext : allnodes;
620 for (; np; np = np->allnext) {
621 if (of_match_node(matches, np) && of_node_get(np)) {
628 read_unlock(&devtree_lock);
631 EXPORT_SYMBOL(of_find_matching_node);
634 * of_modalias_node - Lookup appropriate modalias for a device node
635 * @node: pointer to a device tree node
636 * @modalias: Pointer to buffer that modalias value will be copied into
637 * @len: Length of modalias value
639 * Based on the value of the compatible property, this routine will attempt
640 * to choose an appropriate modalias value for a particular device tree node.
641 * It does this by stripping the manufacturer prefix (as delimited by a ',')
642 * from the first entry in the compatible list property.
644 * This routine returns 0 on success, <0 on failure.
646 int of_modalias_node(struct device_node *node, char *modalias, int len)
648 const char *compatible, *p;
651 compatible = of_get_property(node, "compatible", &cplen);
652 if (!compatible || strlen(compatible) > cplen)
654 p = strchr(compatible, ',');
655 strlcpy(modalias, p ? p + 1 : compatible, len);
658 EXPORT_SYMBOL_GPL(of_modalias_node);
661 * of_find_node_by_phandle - Find a node given a phandle
662 * @handle: phandle of the node to find
664 * Returns a node pointer with refcount incremented, use
665 * of_node_put() on it when done.
667 struct device_node *of_find_node_by_phandle(phandle handle)
669 struct device_node *np;
671 read_lock(&devtree_lock);
672 for (np = allnodes; np; np = np->allnext)
673 if (np->phandle == handle)
676 read_unlock(&devtree_lock);
679 EXPORT_SYMBOL(of_find_node_by_phandle);
682 * of_property_read_u8_array - Find and read an array of u8 from a property.
684 * @np: device node from which the property value is to be read.
685 * @propname: name of the property to be searched.
686 * @out_value: pointer to return value, modified only if return value is 0.
687 * @sz: number of array elements to read
689 * Search for a property in a device node and read 8-bit value(s) from
690 * it. Returns 0 on success, -EINVAL if the property does not exist,
691 * -ENODATA if property does not have a value, and -EOVERFLOW if the
692 * property data isn't large enough.
694 * dts entry of array should be like:
695 * property = /bits/ 8 <0x50 0x60 0x70>;
697 * The out_value is modified only if a valid u8 value can be decoded.
699 int of_property_read_u8_array(const struct device_node *np,
700 const char *propname, u8 *out_values, size_t sz)
702 struct property *prop = of_find_property(np, propname, NULL);
709 if ((sz * sizeof(*out_values)) > prop->length)
714 *out_values++ = *val++;
717 EXPORT_SYMBOL_GPL(of_property_read_u8_array);
720 * of_property_read_u16_array - Find and read an array of u16 from a property.
722 * @np: device node from which the property value is to be read.
723 * @propname: name of the property to be searched.
724 * @out_value: pointer to return value, modified only if return value is 0.
725 * @sz: number of array elements to read
727 * Search for a property in a device node and read 16-bit value(s) from
728 * it. Returns 0 on success, -EINVAL if the property does not exist,
729 * -ENODATA if property does not have a value, and -EOVERFLOW if the
730 * property data isn't large enough.
732 * dts entry of array should be like:
733 * property = /bits/ 16 <0x5000 0x6000 0x7000>;
735 * The out_value is modified only if a valid u16 value can be decoded.
737 int of_property_read_u16_array(const struct device_node *np,
738 const char *propname, u16 *out_values, size_t sz)
740 struct property *prop = of_find_property(np, propname, NULL);
747 if ((sz * sizeof(*out_values)) > prop->length)
752 *out_values++ = be16_to_cpup(val++);
755 EXPORT_SYMBOL_GPL(of_property_read_u16_array);
758 * of_property_read_u32_array - Find and read an array of 32 bit integers
761 * @np: device node from which the property value is to be read.
762 * @propname: name of the property to be searched.
763 * @out_value: pointer to return value, modified only if return value is 0.
764 * @sz: number of array elements to read
766 * Search for a property in a device node and read 32-bit value(s) from
767 * it. Returns 0 on success, -EINVAL if the property does not exist,
768 * -ENODATA if property does not have a value, and -EOVERFLOW if the
769 * property data isn't large enough.
771 * The out_value is modified only if a valid u32 value can be decoded.
773 int of_property_read_u32_array(const struct device_node *np,
774 const char *propname, u32 *out_values,
777 struct property *prop = of_find_property(np, propname, NULL);
784 if ((sz * sizeof(*out_values)) > prop->length)
789 *out_values++ = be32_to_cpup(val++);
792 EXPORT_SYMBOL_GPL(of_property_read_u32_array);
795 * of_property_read_u64 - Find and read a 64 bit integer from a property
796 * @np: device node from which the property value is to be read.
797 * @propname: name of the property to be searched.
798 * @out_value: pointer to return value, modified only if return value is 0.
800 * Search for a property in a device node and read a 64-bit value from
801 * it. Returns 0 on success, -EINVAL if the property does not exist,
802 * -ENODATA if property does not have a value, and -EOVERFLOW if the
803 * property data isn't large enough.
805 * The out_value is modified only if a valid u64 value can be decoded.
807 int of_property_read_u64(const struct device_node *np, const char *propname,
810 struct property *prop = of_find_property(np, propname, NULL);
816 if (sizeof(*out_value) > prop->length)
818 *out_value = of_read_number(prop->value, 2);
821 EXPORT_SYMBOL_GPL(of_property_read_u64);
824 * of_property_read_string - Find and read a string from a property
825 * @np: device node from which the property value is to be read.
826 * @propname: name of the property to be searched.
827 * @out_string: pointer to null terminated return string, modified only if
830 * Search for a property in a device tree node and retrieve a null
831 * terminated string value (pointer to data, not a copy). Returns 0 on
832 * success, -EINVAL if the property does not exist, -ENODATA if property
833 * does not have a value, and -EILSEQ if the string is not null-terminated
834 * within the length of the property data.
836 * The out_string pointer is modified only if a valid string can be decoded.
838 int of_property_read_string(struct device_node *np, const char *propname,
839 const char **out_string)
841 struct property *prop = of_find_property(np, propname, NULL);
846 if (strnlen(prop->value, prop->length) >= prop->length)
848 *out_string = prop->value;
851 EXPORT_SYMBOL_GPL(of_property_read_string);
854 * of_property_read_string_index - Find and read a string from a multiple
856 * @np: device node from which the property value is to be read.
857 * @propname: name of the property to be searched.
858 * @index: index of the string in the list of strings
859 * @out_string: pointer to null terminated return string, modified only if
862 * Search for a property in a device tree node and retrieve a null
863 * terminated string value (pointer to data, not a copy) in the list of strings
864 * contained in that property.
865 * Returns 0 on success, -EINVAL if the property does not exist, -ENODATA if
866 * property does not have a value, and -EILSEQ if the string is not
867 * null-terminated within the length of the property data.
869 * The out_string pointer is modified only if a valid string can be decoded.
871 int of_property_read_string_index(struct device_node *np, const char *propname,
872 int index, const char **output)
874 struct property *prop = of_find_property(np, propname, NULL);
876 size_t l = 0, total = 0;
883 if (strnlen(prop->value, prop->length) >= prop->length)
888 for (i = 0; total < prop->length; total += l, p += l) {
897 EXPORT_SYMBOL_GPL(of_property_read_string_index);
900 * of_property_match_string() - Find string in a list and return index
901 * @np: pointer to node containing string list property
902 * @propname: string list property name
903 * @string: pointer to string to search for in string list
905 * This function searches a string list property and returns the index
906 * of a specific string value.
908 int of_property_match_string(struct device_node *np, const char *propname,
911 struct property *prop = of_find_property(np, propname, NULL);
922 end = p + prop->length;
924 for (i = 0; p < end; i++, p += l) {
928 pr_debug("comparing %s with %s\n", string, p);
929 if (strcmp(string, p) == 0)
930 return i; /* Found it; return index */
934 EXPORT_SYMBOL_GPL(of_property_match_string);
937 * of_property_count_strings - Find and return the number of strings from a
938 * multiple strings property.
939 * @np: device node from which the property value is to be read.
940 * @propname: name of the property to be searched.
942 * Search for a property in a device tree node and retrieve the number of null
943 * terminated string contain in it. Returns the number of strings on
944 * success, -EINVAL if the property does not exist, -ENODATA if property
945 * does not have a value, and -EILSEQ if the string is not null-terminated
946 * within the length of the property data.
948 int of_property_count_strings(struct device_node *np, const char *propname)
950 struct property *prop = of_find_property(np, propname, NULL);
952 size_t l = 0, total = 0;
959 if (strnlen(prop->value, prop->length) >= prop->length)
964 for (i = 0; total < prop->length; total += l, p += l, i++)
969 EXPORT_SYMBOL_GPL(of_property_count_strings);
972 * of_parse_phandle - Resolve a phandle property to a device_node pointer
973 * @np: Pointer to device node holding phandle property
974 * @phandle_name: Name of property holding a phandle value
975 * @index: For properties holding a table of phandles, this is the index into
978 * Returns the device_node pointer with refcount incremented. Use
979 * of_node_put() on it when done.
982 of_parse_phandle(struct device_node *np, const char *phandle_name, int index)
984 const __be32 *phandle;
987 phandle = of_get_property(np, phandle_name, &size);
988 if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
991 return of_find_node_by_phandle(be32_to_cpup(phandle + index));
993 EXPORT_SYMBOL(of_parse_phandle);
996 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
997 * @np: pointer to a device tree node containing a list
998 * @list_name: property name that contains a list
999 * @cells_name: property name that specifies phandles' arguments count
1000 * @index: index of a phandle to parse out
1001 * @out_args: optional pointer to output arguments structure (will be filled)
1003 * This function is useful to parse lists of phandles and their arguments.
1004 * Returns 0 on success and fills out_args, on error returns appropriate
1007 * Caller is responsible to call of_node_put() on the returned out_args->node
1013 * #list-cells = <2>;
1017 * #list-cells = <1>;
1021 * list = <&phandle1 1 2 &phandle2 3>;
1024 * To get a device_node of the `node2' node you may call this:
1025 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
1027 int of_parse_phandle_with_args(struct device_node *np, const char *list_name,
1028 const char *cells_name, int index,
1029 struct of_phandle_args *out_args)
1031 const __be32 *list, *list_end;
1032 int size, cur_index = 0;
1034 struct device_node *node = NULL;
1037 /* Retrieve the phandle list property */
1038 list = of_get_property(np, list_name, &size);
1041 list_end = list + size / sizeof(*list);
1043 /* Loop over the phandles until all the requested entry is found */
1044 while (list < list_end) {
1048 * If phandle is 0, then it is an empty entry with no
1049 * arguments. Skip forward to the next entry.
1051 phandle = be32_to_cpup(list++);
1054 * Find the provider node and parse the #*-cells
1055 * property to determine the argument length
1057 node = of_find_node_by_phandle(phandle);
1059 pr_err("%s: could not find phandle\n",
1063 if (of_property_read_u32(node, cells_name, &count)) {
1064 pr_err("%s: could not get %s for %s\n",
1065 np->full_name, cells_name,
1071 * Make sure that the arguments actually fit in the
1072 * remaining property data length
1074 if (list + count > list_end) {
1075 pr_err("%s: arguments longer than property\n",
1082 * All of the error cases above bail out of the loop, so at
1083 * this point, the parsing is successful. If the requested
1084 * index matches, then fill the out_args structure and return,
1085 * or return -ENOENT for an empty entry.
1087 if (cur_index == index) {
1093 if (WARN_ON(count > MAX_PHANDLE_ARGS))
1094 count = MAX_PHANDLE_ARGS;
1095 out_args->np = node;
1096 out_args->args_count = count;
1097 for (i = 0; i < count; i++)
1098 out_args->args[i] = be32_to_cpup(list++);
1109 /* Loop exited without finding a valid entry; return an error */
1114 EXPORT_SYMBOL(of_parse_phandle_with_args);
1117 * prom_add_property - Add a property to a node
1119 int prom_add_property(struct device_node *np, struct property *prop)
1121 struct property **next;
1122 unsigned long flags;
1125 write_lock_irqsave(&devtree_lock, flags);
1126 next = &np->properties;
1128 if (strcmp(prop->name, (*next)->name) == 0) {
1129 /* duplicate ! don't insert it */
1130 write_unlock_irqrestore(&devtree_lock, flags);
1133 next = &(*next)->next;
1136 write_unlock_irqrestore(&devtree_lock, flags);
1138 #ifdef CONFIG_PROC_DEVICETREE
1139 /* try to add to proc as well if it was initialized */
1141 proc_device_tree_add_prop(np->pde, prop);
1142 #endif /* CONFIG_PROC_DEVICETREE */
1148 * prom_remove_property - Remove a property from a node.
1150 * Note that we don't actually remove it, since we have given out
1151 * who-knows-how-many pointers to the data using get-property.
1152 * Instead we just move the property to the "dead properties"
1153 * list, so it won't be found any more.
1155 int prom_remove_property(struct device_node *np, struct property *prop)
1157 struct property **next;
1158 unsigned long flags;
1161 write_lock_irqsave(&devtree_lock, flags);
1162 next = &np->properties;
1164 if (*next == prop) {
1165 /* found the node */
1167 prop->next = np->deadprops;
1168 np->deadprops = prop;
1172 next = &(*next)->next;
1174 write_unlock_irqrestore(&devtree_lock, flags);
1179 #ifdef CONFIG_PROC_DEVICETREE
1180 /* try to remove the proc node as well */
1182 proc_device_tree_remove_prop(np->pde, prop);
1183 #endif /* CONFIG_PROC_DEVICETREE */
1189 * prom_update_property - Update a property in a node, if the property does
1190 * not exist, add it.
1192 * Note that we don't actually remove it, since we have given out
1193 * who-knows-how-many pointers to the data using get-property.
1194 * Instead we just move the property to the "dead properties" list,
1195 * and add the new property to the property list
1197 int prom_update_property(struct device_node *np,
1198 struct property *newprop)
1200 struct property **next, *oldprop;
1201 unsigned long flags;
1207 oldprop = of_find_property(np, newprop->name, NULL);
1209 return prom_add_property(np, newprop);
1211 write_lock_irqsave(&devtree_lock, flags);
1212 next = &np->properties;
1214 if (*next == oldprop) {
1215 /* found the node */
1216 newprop->next = oldprop->next;
1218 oldprop->next = np->deadprops;
1219 np->deadprops = oldprop;
1223 next = &(*next)->next;
1225 write_unlock_irqrestore(&devtree_lock, flags);
1230 #ifdef CONFIG_PROC_DEVICETREE
1231 /* try to add to proc as well if it was initialized */
1233 proc_device_tree_update_prop(np->pde, newprop, oldprop);
1234 #endif /* CONFIG_PROC_DEVICETREE */
1239 #if defined(CONFIG_OF_DYNAMIC)
1241 * Support for dynamic device trees.
1243 * On some platforms, the device tree can be manipulated at runtime.
1244 * The routines in this section support adding, removing and changing
1245 * device tree nodes.
1249 * of_attach_node - Plug a device node into the tree and global list.
1251 void of_attach_node(struct device_node *np)
1253 unsigned long flags;
1255 write_lock_irqsave(&devtree_lock, flags);
1256 np->sibling = np->parent->child;
1257 np->allnext = allnodes;
1258 np->parent->child = np;
1260 write_unlock_irqrestore(&devtree_lock, flags);
1264 * of_detach_node - "Unplug" a node from the device tree.
1266 * The caller must hold a reference to the node. The memory associated with
1267 * the node is not freed until its refcount goes to zero.
1269 void of_detach_node(struct device_node *np)
1271 struct device_node *parent;
1272 unsigned long flags;
1274 write_lock_irqsave(&devtree_lock, flags);
1276 parent = np->parent;
1281 allnodes = np->allnext;
1283 struct device_node *prev;
1284 for (prev = allnodes;
1285 prev->allnext != np;
1286 prev = prev->allnext)
1288 prev->allnext = np->allnext;
1291 if (parent->child == np)
1292 parent->child = np->sibling;
1294 struct device_node *prevsib;
1295 for (prevsib = np->parent->child;
1296 prevsib->sibling != np;
1297 prevsib = prevsib->sibling)
1299 prevsib->sibling = np->sibling;
1302 of_node_set_flag(np, OF_DETACHED);
1305 write_unlock_irqrestore(&devtree_lock, flags);
1307 #endif /* defined(CONFIG_OF_DYNAMIC) */
1309 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1310 int id, const char *stem, int stem_len)
1314 strncpy(ap->stem, stem, stem_len);
1315 ap->stem[stem_len] = 0;
1316 list_add_tail(&ap->link, &aliases_lookup);
1317 pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
1318 ap->alias, ap->stem, ap->id, of_node_full_name(np));
1322 * of_alias_scan - Scan all properties of 'aliases' node
1324 * The function scans all the properties of 'aliases' node and populate
1325 * the the global lookup table with the properties. It returns the
1326 * number of alias_prop found, or error code in error case.
1328 * @dt_alloc: An allocator that provides a virtual address to memory
1329 * for the resulting tree
1331 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1333 struct property *pp;
1335 of_chosen = of_find_node_by_path("/chosen");
1336 if (of_chosen == NULL)
1337 of_chosen = of_find_node_by_path("/chosen@0");
1338 of_aliases = of_find_node_by_path("/aliases");
1342 for_each_property_of_node(of_aliases, pp) {
1343 const char *start = pp->name;
1344 const char *end = start + strlen(start);
1345 struct device_node *np;
1346 struct alias_prop *ap;
1349 /* Skip those we do not want to proceed */
1350 if (!strcmp(pp->name, "name") ||
1351 !strcmp(pp->name, "phandle") ||
1352 !strcmp(pp->name, "linux,phandle"))
1355 np = of_find_node_by_path(pp->value);
1359 /* walk the alias backwards to extract the id and work out
1360 * the 'stem' string */
1361 while (isdigit(*(end-1)) && end > start)
1365 if (kstrtoint(end, 10, &id) < 0)
1368 /* Allocate an alias_prop with enough space for the stem */
1369 ap = dt_alloc(sizeof(*ap) + len + 1, 4);
1373 of_alias_add(ap, np, id, start, len);
1378 * of_alias_get_id - Get alias id for the given device_node
1379 * @np: Pointer to the given device_node
1380 * @stem: Alias stem of the given device_node
1382 * The function travels the lookup table to get alias id for the given
1383 * device_node and alias stem. It returns the alias id if find it.
1385 int of_alias_get_id(struct device_node *np, const char *stem)
1387 struct alias_prop *app;
1390 mutex_lock(&of_aliases_mutex);
1391 list_for_each_entry(app, &aliases_lookup, link) {
1392 if (strcmp(app->stem, stem) != 0)
1395 if (np == app->np) {
1400 mutex_unlock(&of_aliases_mutex);
1404 EXPORT_SYMBOL_GPL(of_alias_get_id);
1406 const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
1409 const void *curv = cur;
1419 curv += sizeof(*cur);
1420 if (curv >= prop->value + prop->length)
1424 *pu = be32_to_cpup(curv);
1427 EXPORT_SYMBOL_GPL(of_prop_next_u32);
1429 const char *of_prop_next_string(struct property *prop, const char *cur)
1431 const void *curv = cur;
1439 curv += strlen(cur) + 1;
1440 if (curv >= prop->value + prop->length)
1445 EXPORT_SYMBOL_GPL(of_prop_next_string);