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_child_by_name - Find the child node by name for a given parent
369 * @name: child name to look for.
371 * This function looks for child node for given matching name
373 * Returns a node pointer if found, with refcount incremented, use
374 * of_node_put() on it when done.
375 * Returns NULL if node is not found.
377 struct device_node *of_get_child_by_name(const struct device_node *node,
380 struct device_node *child;
382 for_each_child_of_node(node, child)
383 if (child->name && (of_node_cmp(child->name, name) == 0))
387 EXPORT_SYMBOL(of_get_child_by_name);
390 * of_find_node_by_path - Find a node matching a full OF path
391 * @path: The full path to match
393 * Returns a node pointer with refcount incremented, use
394 * of_node_put() on it when done.
396 struct device_node *of_find_node_by_path(const char *path)
398 struct device_node *np = allnodes;
400 read_lock(&devtree_lock);
401 for (; np; np = np->allnext) {
402 if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
406 read_unlock(&devtree_lock);
409 EXPORT_SYMBOL(of_find_node_by_path);
412 * of_find_node_by_name - Find a node by its "name" property
413 * @from: The node to start searching from or NULL, the node
414 * you pass will not be searched, only the next one
415 * will; typically, you pass what the previous call
416 * returned. of_node_put() will be called on it
417 * @name: The name string to match against
419 * Returns a node pointer with refcount incremented, use
420 * of_node_put() on it when done.
422 struct device_node *of_find_node_by_name(struct device_node *from,
425 struct device_node *np;
427 read_lock(&devtree_lock);
428 np = from ? from->allnext : allnodes;
429 for (; np; np = np->allnext)
430 if (np->name && (of_node_cmp(np->name, name) == 0)
434 read_unlock(&devtree_lock);
437 EXPORT_SYMBOL(of_find_node_by_name);
440 * of_find_node_by_type - Find a node by its "device_type" property
441 * @from: The node to start searching from, or NULL to start searching
442 * the entire device tree. The node you pass will not be
443 * searched, only the next one will; typically, you pass
444 * what the previous call returned. of_node_put() will be
445 * called on from for you.
446 * @type: The type string to match against
448 * Returns a node pointer with refcount incremented, use
449 * of_node_put() on it when done.
451 struct device_node *of_find_node_by_type(struct device_node *from,
454 struct device_node *np;
456 read_lock(&devtree_lock);
457 np = from ? from->allnext : allnodes;
458 for (; np; np = np->allnext)
459 if (np->type && (of_node_cmp(np->type, type) == 0)
463 read_unlock(&devtree_lock);
466 EXPORT_SYMBOL(of_find_node_by_type);
469 * of_find_compatible_node - Find a node based on type and one of the
470 * tokens in its "compatible" property
471 * @from: The node to start searching from or NULL, the node
472 * you pass will not be searched, only the next one
473 * will; typically, you pass what the previous call
474 * returned. of_node_put() will be called on it
475 * @type: The type string to match "device_type" or NULL to ignore
476 * @compatible: The string to match to one of the tokens in the device
479 * Returns a node pointer with refcount incremented, use
480 * of_node_put() on it when done.
482 struct device_node *of_find_compatible_node(struct device_node *from,
483 const char *type, const char *compatible)
485 struct device_node *np;
487 read_lock(&devtree_lock);
488 np = from ? from->allnext : allnodes;
489 for (; np; np = np->allnext) {
491 && !(np->type && (of_node_cmp(np->type, type) == 0)))
493 if (of_device_is_compatible(np, compatible) && of_node_get(np))
497 read_unlock(&devtree_lock);
500 EXPORT_SYMBOL(of_find_compatible_node);
503 * of_find_node_with_property - Find a node which has a property with
505 * @from: The node to start searching from or NULL, the node
506 * you pass will not be searched, only the next one
507 * will; typically, you pass what the previous call
508 * returned. of_node_put() will be called on it
509 * @prop_name: The name of the property to look for.
511 * Returns a node pointer with refcount incremented, use
512 * of_node_put() on it when done.
514 struct device_node *of_find_node_with_property(struct device_node *from,
515 const char *prop_name)
517 struct device_node *np;
520 read_lock(&devtree_lock);
521 np = from ? from->allnext : allnodes;
522 for (; np; np = np->allnext) {
523 for (pp = np->properties; pp; pp = pp->next) {
524 if (of_prop_cmp(pp->name, prop_name) == 0) {
532 read_unlock(&devtree_lock);
535 EXPORT_SYMBOL(of_find_node_with_property);
538 * of_match_node - Tell if an device_node has a matching of_match structure
539 * @matches: array of of device match structures to search in
540 * @node: the of device structure to match against
542 * Low level utility function used by device matching.
544 const struct of_device_id *of_match_node(const struct of_device_id *matches,
545 const struct device_node *node)
550 while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
552 if (matches->name[0])
554 && !strcmp(matches->name, node->name);
555 if (matches->type[0])
557 && !strcmp(matches->type, node->type);
558 if (matches->compatible[0])
559 match &= of_device_is_compatible(node,
560 matches->compatible);
567 EXPORT_SYMBOL(of_match_node);
570 * of_find_matching_node - Find a node based on an of_device_id match
572 * @from: The node to start searching from or NULL, the node
573 * you pass will not be searched, only the next one
574 * will; typically, you pass what the previous call
575 * returned. of_node_put() will be called on it
576 * @matches: array of of device match structures to search in
578 * Returns a node pointer with refcount incremented, use
579 * of_node_put() on it when done.
581 struct device_node *of_find_matching_node(struct device_node *from,
582 const struct of_device_id *matches)
584 struct device_node *np;
586 read_lock(&devtree_lock);
587 np = from ? from->allnext : allnodes;
588 for (; np; np = np->allnext) {
589 if (of_match_node(matches, np) && of_node_get(np))
593 read_unlock(&devtree_lock);
596 EXPORT_SYMBOL(of_find_matching_node);
599 * of_modalias_node - Lookup appropriate modalias for a device node
600 * @node: pointer to a device tree node
601 * @modalias: Pointer to buffer that modalias value will be copied into
602 * @len: Length of modalias value
604 * Based on the value of the compatible property, this routine will attempt
605 * to choose an appropriate modalias value for a particular device tree node.
606 * It does this by stripping the manufacturer prefix (as delimited by a ',')
607 * from the first entry in the compatible list property.
609 * This routine returns 0 on success, <0 on failure.
611 int of_modalias_node(struct device_node *node, char *modalias, int len)
613 const char *compatible, *p;
616 compatible = of_get_property(node, "compatible", &cplen);
617 if (!compatible || strlen(compatible) > cplen)
619 p = strchr(compatible, ',');
620 strlcpy(modalias, p ? p + 1 : compatible, len);
623 EXPORT_SYMBOL_GPL(of_modalias_node);
626 * of_find_node_by_phandle - Find a node given a phandle
627 * @handle: phandle of the node to find
629 * Returns a node pointer with refcount incremented, use
630 * of_node_put() on it when done.
632 struct device_node *of_find_node_by_phandle(phandle handle)
634 struct device_node *np;
636 read_lock(&devtree_lock);
637 for (np = allnodes; np; np = np->allnext)
638 if (np->phandle == handle)
641 read_unlock(&devtree_lock);
644 EXPORT_SYMBOL(of_find_node_by_phandle);
647 * of_property_read_u32_array - Find and read an array of 32 bit integers
650 * @np: device node from which the property value is to be read.
651 * @propname: name of the property to be searched.
652 * @out_value: pointer to return value, modified only if return value is 0.
654 * Search for a property in a device node and read 32-bit value(s) from
655 * it. Returns 0 on success, -EINVAL if the property does not exist,
656 * -ENODATA if property does not have a value, and -EOVERFLOW if the
657 * property data isn't large enough.
659 * The out_value is modified only if a valid u32 value can be decoded.
661 int of_property_read_u32_array(const struct device_node *np,
662 const char *propname, u32 *out_values,
665 struct property *prop = of_find_property(np, propname, NULL);
672 if ((sz * sizeof(*out_values)) > prop->length)
677 *out_values++ = be32_to_cpup(val++);
680 EXPORT_SYMBOL_GPL(of_property_read_u32_array);
683 * of_property_read_u64 - Find and read a 64 bit integer 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.
688 * Search for a property in a device node and read a 64-bit value from
689 * it. Returns 0 on success, -EINVAL if the property does not exist,
690 * -ENODATA if property does not have a value, and -EOVERFLOW if the
691 * property data isn't large enough.
693 * The out_value is modified only if a valid u64 value can be decoded.
695 int of_property_read_u64(const struct device_node *np, const char *propname,
698 struct property *prop = of_find_property(np, propname, NULL);
704 if (sizeof(*out_value) > prop->length)
706 *out_value = of_read_number(prop->value, 2);
709 EXPORT_SYMBOL_GPL(of_property_read_u64);
712 * of_property_read_string - Find and read a string from a property
713 * @np: device node from which the property value is to be read.
714 * @propname: name of the property to be searched.
715 * @out_string: pointer to null terminated return string, modified only if
718 * Search for a property in a device tree node and retrieve a null
719 * terminated string value (pointer to data, not a copy). Returns 0 on
720 * success, -EINVAL if the property does not exist, -ENODATA if property
721 * does not have a value, and -EILSEQ if the string is not null-terminated
722 * within the length of the property data.
724 * The out_string pointer is modified only if a valid string can be decoded.
726 int of_property_read_string(struct device_node *np, const char *propname,
727 const char **out_string)
729 struct property *prop = of_find_property(np, propname, NULL);
734 if (strnlen(prop->value, prop->length) >= prop->length)
736 *out_string = prop->value;
739 EXPORT_SYMBOL_GPL(of_property_read_string);
742 * of_property_read_string_index - Find and read a string from a multiple
744 * @np: device node from which the property value is to be read.
745 * @propname: name of the property to be searched.
746 * @index: index of the string in the list of strings
747 * @out_string: pointer to null terminated return string, modified only if
750 * Search for a property in a device tree node and retrieve a null
751 * terminated string value (pointer to data, not a copy) in the list of strings
752 * contained in that property.
753 * Returns 0 on success, -EINVAL if the property does not exist, -ENODATA if
754 * property does not have a value, and -EILSEQ if the string is not
755 * null-terminated within the length of the property data.
757 * The out_string pointer is modified only if a valid string can be decoded.
759 int of_property_read_string_index(struct device_node *np, const char *propname,
760 int index, const char **output)
762 struct property *prop = of_find_property(np, propname, NULL);
764 size_t l = 0, total = 0;
771 if (strnlen(prop->value, prop->length) >= prop->length)
776 for (i = 0; total < prop->length; total += l, p += l) {
785 EXPORT_SYMBOL_GPL(of_property_read_string_index);
788 * of_property_match_string() - Find string in a list and return index
789 * @np: pointer to node containing string list property
790 * @propname: string list property name
791 * @string: pointer to string to search for in string list
793 * This function searches a string list property and returns the index
794 * of a specific string value.
796 int of_property_match_string(struct device_node *np, const char *propname,
799 struct property *prop = of_find_property(np, propname, NULL);
810 end = p + prop->length;
812 for (i = 0; p < end; i++, p += l) {
816 pr_debug("comparing %s with %s\n", string, p);
817 if (strcmp(string, p) == 0)
818 return i; /* Found it; return index */
822 EXPORT_SYMBOL_GPL(of_property_match_string);
825 * of_property_count_strings - Find and return the number of strings from a
826 * multiple strings property.
827 * @np: device node from which the property value is to be read.
828 * @propname: name of the property to be searched.
830 * Search for a property in a device tree node and retrieve the number of null
831 * terminated string contain in it. Returns the number of strings 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 int of_property_count_strings(struct device_node *np, const char *propname)
838 struct property *prop = of_find_property(np, propname, NULL);
840 size_t l = 0, total = 0;
847 if (strnlen(prop->value, prop->length) >= prop->length)
852 for (i = 0; total < prop->length; total += l, p += l, i++)
857 EXPORT_SYMBOL_GPL(of_property_count_strings);
860 * of_parse_phandle - Resolve a phandle property to a device_node pointer
861 * @np: Pointer to device node holding phandle property
862 * @phandle_name: Name of property holding a phandle value
863 * @index: For properties holding a table of phandles, this is the index into
866 * Returns the device_node pointer with refcount incremented. Use
867 * of_node_put() on it when done.
870 of_parse_phandle(struct device_node *np, const char *phandle_name, int index)
872 const __be32 *phandle;
875 phandle = of_get_property(np, phandle_name, &size);
876 if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
879 return of_find_node_by_phandle(be32_to_cpup(phandle + index));
881 EXPORT_SYMBOL(of_parse_phandle);
884 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
885 * @np: pointer to a device tree node containing a list
886 * @list_name: property name that contains a list
887 * @cells_name: property name that specifies phandles' arguments count
888 * @index: index of a phandle to parse out
889 * @out_args: optional pointer to output arguments structure (will be filled)
891 * This function is useful to parse lists of phandles and their arguments.
892 * Returns 0 on success and fills out_args, on error returns appropriate
895 * Caller is responsible to call of_node_put() on the returned out_args->node
909 * list = <&phandle1 1 2 &phandle2 3>;
912 * To get a device_node of the `node2' node you may call this:
913 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
915 int of_parse_phandle_with_args(struct device_node *np, const char *list_name,
916 const char *cells_name, int index,
917 struct of_phandle_args *out_args)
919 const __be32 *list, *list_end;
920 int size, cur_index = 0;
922 struct device_node *node = NULL;
925 /* Retrieve the phandle list property */
926 list = of_get_property(np, list_name, &size);
929 list_end = list + size / sizeof(*list);
931 /* Loop over the phandles until all the requested entry is found */
932 while (list < list_end) {
936 * If phandle is 0, then it is an empty entry with no
937 * arguments. Skip forward to the next entry.
939 phandle = be32_to_cpup(list++);
942 * Find the provider node and parse the #*-cells
943 * property to determine the argument length
945 node = of_find_node_by_phandle(phandle);
947 pr_err("%s: could not find phandle\n",
951 if (of_property_read_u32(node, cells_name, &count)) {
952 pr_err("%s: could not get %s for %s\n",
953 np->full_name, cells_name,
959 * Make sure that the arguments actually fit in the
960 * remaining property data length
962 if (list + count > list_end) {
963 pr_err("%s: arguments longer than property\n",
970 * All of the error cases above bail out of the loop, so at
971 * this point, the parsing is successful. If the requested
972 * index matches, then fill the out_args structure and return,
973 * or return -ENOENT for an empty entry.
975 if (cur_index == index) {
981 if (WARN_ON(count > MAX_PHANDLE_ARGS))
982 count = MAX_PHANDLE_ARGS;
984 out_args->args_count = count;
985 for (i = 0; i < count; i++)
986 out_args->args[i] = be32_to_cpup(list++);
997 /* Loop exited without finding a valid entry; return an error */
1002 EXPORT_SYMBOL(of_parse_phandle_with_args);
1005 * prom_add_property - Add a property to a node
1007 int prom_add_property(struct device_node *np, struct property *prop)
1009 struct property **next;
1010 unsigned long flags;
1013 write_lock_irqsave(&devtree_lock, flags);
1014 next = &np->properties;
1016 if (strcmp(prop->name, (*next)->name) == 0) {
1017 /* duplicate ! don't insert it */
1018 write_unlock_irqrestore(&devtree_lock, flags);
1021 next = &(*next)->next;
1024 write_unlock_irqrestore(&devtree_lock, flags);
1026 #ifdef CONFIG_PROC_DEVICETREE
1027 /* try to add to proc as well if it was initialized */
1029 proc_device_tree_add_prop(np->pde, prop);
1030 #endif /* CONFIG_PROC_DEVICETREE */
1036 * prom_remove_property - Remove a property from a node.
1038 * Note that we don't actually remove it, since we have given out
1039 * who-knows-how-many pointers to the data using get-property.
1040 * Instead we just move the property to the "dead properties"
1041 * list, so it won't be found any more.
1043 int prom_remove_property(struct device_node *np, struct property *prop)
1045 struct property **next;
1046 unsigned long flags;
1049 write_lock_irqsave(&devtree_lock, flags);
1050 next = &np->properties;
1052 if (*next == prop) {
1053 /* found the node */
1055 prop->next = np->deadprops;
1056 np->deadprops = prop;
1060 next = &(*next)->next;
1062 write_unlock_irqrestore(&devtree_lock, flags);
1067 #ifdef CONFIG_PROC_DEVICETREE
1068 /* try to remove the proc node as well */
1070 proc_device_tree_remove_prop(np->pde, prop);
1071 #endif /* CONFIG_PROC_DEVICETREE */
1077 * prom_update_property - Update a property in a node, if the property does
1078 * not exist, add it.
1080 * Note that we don't actually remove it, since we have given out
1081 * who-knows-how-many pointers to the data using get-property.
1082 * Instead we just move the property to the "dead properties" list,
1083 * and add the new property to the property list
1085 int prom_update_property(struct device_node *np,
1086 struct property *newprop)
1088 struct property **next, *oldprop;
1089 unsigned long flags;
1095 oldprop = of_find_property(np, newprop->name, NULL);
1097 return prom_add_property(np, newprop);
1099 write_lock_irqsave(&devtree_lock, flags);
1100 next = &np->properties;
1102 if (*next == oldprop) {
1103 /* found the node */
1104 newprop->next = oldprop->next;
1106 oldprop->next = np->deadprops;
1107 np->deadprops = oldprop;
1111 next = &(*next)->next;
1113 write_unlock_irqrestore(&devtree_lock, flags);
1118 #ifdef CONFIG_PROC_DEVICETREE
1119 /* try to add to proc as well if it was initialized */
1121 proc_device_tree_update_prop(np->pde, newprop, oldprop);
1122 #endif /* CONFIG_PROC_DEVICETREE */
1127 #if defined(CONFIG_OF_DYNAMIC)
1129 * Support for dynamic device trees.
1131 * On some platforms, the device tree can be manipulated at runtime.
1132 * The routines in this section support adding, removing and changing
1133 * device tree nodes.
1137 * of_attach_node - Plug a device node into the tree and global list.
1139 void of_attach_node(struct device_node *np)
1141 unsigned long flags;
1143 write_lock_irqsave(&devtree_lock, flags);
1144 np->sibling = np->parent->child;
1145 np->allnext = allnodes;
1146 np->parent->child = np;
1148 write_unlock_irqrestore(&devtree_lock, flags);
1152 * of_detach_node - "Unplug" a node from the device tree.
1154 * The caller must hold a reference to the node. The memory associated with
1155 * the node is not freed until its refcount goes to zero.
1157 void of_detach_node(struct device_node *np)
1159 struct device_node *parent;
1160 unsigned long flags;
1162 write_lock_irqsave(&devtree_lock, flags);
1164 parent = np->parent;
1169 allnodes = np->allnext;
1171 struct device_node *prev;
1172 for (prev = allnodes;
1173 prev->allnext != np;
1174 prev = prev->allnext)
1176 prev->allnext = np->allnext;
1179 if (parent->child == np)
1180 parent->child = np->sibling;
1182 struct device_node *prevsib;
1183 for (prevsib = np->parent->child;
1184 prevsib->sibling != np;
1185 prevsib = prevsib->sibling)
1187 prevsib->sibling = np->sibling;
1190 of_node_set_flag(np, OF_DETACHED);
1193 write_unlock_irqrestore(&devtree_lock, flags);
1195 #endif /* defined(CONFIG_OF_DYNAMIC) */
1197 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1198 int id, const char *stem, int stem_len)
1202 strncpy(ap->stem, stem, stem_len);
1203 ap->stem[stem_len] = 0;
1204 list_add_tail(&ap->link, &aliases_lookup);
1205 pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
1206 ap->alias, ap->stem, ap->id, of_node_full_name(np));
1210 * of_alias_scan - Scan all properties of 'aliases' node
1212 * The function scans all the properties of 'aliases' node and populate
1213 * the the global lookup table with the properties. It returns the
1214 * number of alias_prop found, or error code in error case.
1216 * @dt_alloc: An allocator that provides a virtual address to memory
1217 * for the resulting tree
1219 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1221 struct property *pp;
1223 of_chosen = of_find_node_by_path("/chosen");
1224 if (of_chosen == NULL)
1225 of_chosen = of_find_node_by_path("/chosen@0");
1226 of_aliases = of_find_node_by_path("/aliases");
1230 for_each_property_of_node(of_aliases, pp) {
1231 const char *start = pp->name;
1232 const char *end = start + strlen(start);
1233 struct device_node *np;
1234 struct alias_prop *ap;
1237 /* Skip those we do not want to proceed */
1238 if (!strcmp(pp->name, "name") ||
1239 !strcmp(pp->name, "phandle") ||
1240 !strcmp(pp->name, "linux,phandle"))
1243 np = of_find_node_by_path(pp->value);
1247 /* walk the alias backwards to extract the id and work out
1248 * the 'stem' string */
1249 while (isdigit(*(end-1)) && end > start)
1253 if (kstrtoint(end, 10, &id) < 0)
1256 /* Allocate an alias_prop with enough space for the stem */
1257 ap = dt_alloc(sizeof(*ap) + len + 1, 4);
1261 of_alias_add(ap, np, id, start, len);
1266 * of_alias_get_id - Get alias id for the given device_node
1267 * @np: Pointer to the given device_node
1268 * @stem: Alias stem of the given device_node
1270 * The function travels the lookup table to get alias id for the given
1271 * device_node and alias stem. It returns the alias id if find it.
1273 int of_alias_get_id(struct device_node *np, const char *stem)
1275 struct alias_prop *app;
1278 mutex_lock(&of_aliases_mutex);
1279 list_for_each_entry(app, &aliases_lookup, link) {
1280 if (strcmp(app->stem, stem) != 0)
1283 if (np == app->np) {
1288 mutex_unlock(&of_aliases_mutex);
1292 EXPORT_SYMBOL_GPL(of_alias_get_id);
1294 const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
1297 const void *curv = cur;
1307 curv += sizeof(*cur);
1308 if (curv >= prop->value + prop->length)
1312 *pu = be32_to_cpup(curv);
1315 EXPORT_SYMBOL_GPL(of_prop_next_u32);
1317 const char *of_prop_next_string(struct property *prop, const char *cur)
1319 const void *curv = cur;
1327 curv += strlen(cur) + 1;
1328 if (curv >= prop->value + prop->length)
1333 EXPORT_SYMBOL_GPL(of_prop_next_string);