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_SPARC) /* SPARC doesn't do ref counting (yet) */
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_SPARC */
166 struct property *of_find_property(const struct device_node *np,
175 read_lock(&devtree_lock);
176 for (pp = np->properties; pp != 0; 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_find_node_by_path - Find a node matching a full OF path
368 * @path: The full path to match
370 * Returns a node pointer with refcount incremented, use
371 * of_node_put() on it when done.
373 struct device_node *of_find_node_by_path(const char *path)
375 struct device_node *np = allnodes;
377 read_lock(&devtree_lock);
378 for (; np; np = np->allnext) {
379 if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
383 read_unlock(&devtree_lock);
386 EXPORT_SYMBOL(of_find_node_by_path);
389 * of_find_node_by_name - Find a node by its "name" property
390 * @from: The node to start searching from or NULL, the node
391 * you pass will not be searched, only the next one
392 * will; typically, you pass what the previous call
393 * returned. of_node_put() will be called on it
394 * @name: The name string to match against
396 * Returns a node pointer with refcount incremented, use
397 * of_node_put() on it when done.
399 struct device_node *of_find_node_by_name(struct device_node *from,
402 struct device_node *np;
404 read_lock(&devtree_lock);
405 np = from ? from->allnext : allnodes;
406 for (; np; np = np->allnext)
407 if (np->name && (of_node_cmp(np->name, name) == 0)
411 read_unlock(&devtree_lock);
414 EXPORT_SYMBOL(of_find_node_by_name);
417 * of_find_node_by_type - Find a node by its "device_type" property
418 * @from: The node to start searching from, or NULL to start searching
419 * the entire device tree. The node you pass will not be
420 * searched, only the next one will; typically, you pass
421 * what the previous call returned. of_node_put() will be
422 * called on from for you.
423 * @type: The type string to match against
425 * Returns a node pointer with refcount incremented, use
426 * of_node_put() on it when done.
428 struct device_node *of_find_node_by_type(struct device_node *from,
431 struct device_node *np;
433 read_lock(&devtree_lock);
434 np = from ? from->allnext : allnodes;
435 for (; np; np = np->allnext)
436 if (np->type && (of_node_cmp(np->type, type) == 0)
440 read_unlock(&devtree_lock);
443 EXPORT_SYMBOL(of_find_node_by_type);
446 * of_find_compatible_node - Find a node based on type and one of the
447 * tokens in its "compatible" property
448 * @from: The node to start searching from or NULL, the node
449 * you pass will not be searched, only the next one
450 * will; typically, you pass what the previous call
451 * returned. of_node_put() will be called on it
452 * @type: The type string to match "device_type" or NULL to ignore
453 * @compatible: The string to match to one of the tokens in the device
456 * Returns a node pointer with refcount incremented, use
457 * of_node_put() on it when done.
459 struct device_node *of_find_compatible_node(struct device_node *from,
460 const char *type, const char *compatible)
462 struct device_node *np;
464 read_lock(&devtree_lock);
465 np = from ? from->allnext : allnodes;
466 for (; np; np = np->allnext) {
468 && !(np->type && (of_node_cmp(np->type, type) == 0)))
470 if (of_device_is_compatible(np, compatible) && of_node_get(np))
474 read_unlock(&devtree_lock);
477 EXPORT_SYMBOL(of_find_compatible_node);
480 * of_find_node_with_property - Find a node which has a property with
482 * @from: The node to start searching from or NULL, the node
483 * you pass will not be searched, only the next one
484 * will; typically, you pass what the previous call
485 * returned. of_node_put() will be called on it
486 * @prop_name: The name of the property to look for.
488 * Returns a node pointer with refcount incremented, use
489 * of_node_put() on it when done.
491 struct device_node *of_find_node_with_property(struct device_node *from,
492 const char *prop_name)
494 struct device_node *np;
497 read_lock(&devtree_lock);
498 np = from ? from->allnext : allnodes;
499 for (; np; np = np->allnext) {
500 for (pp = np->properties; pp != 0; pp = pp->next) {
501 if (of_prop_cmp(pp->name, prop_name) == 0) {
509 read_unlock(&devtree_lock);
512 EXPORT_SYMBOL(of_find_node_with_property);
515 * of_match_node - Tell if an device_node has a matching of_match structure
516 * @matches: array of of device match structures to search in
517 * @node: the of device structure to match against
519 * Low level utility function used by device matching.
521 const struct of_device_id *of_match_node(const struct of_device_id *matches,
522 const struct device_node *node)
527 while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
529 if (matches->name[0])
531 && !strcmp(matches->name, node->name);
532 if (matches->type[0])
534 && !strcmp(matches->type, node->type);
535 if (matches->compatible[0])
536 match &= of_device_is_compatible(node,
537 matches->compatible);
544 EXPORT_SYMBOL(of_match_node);
547 * of_find_matching_node - Find a node based on an of_device_id match
549 * @from: The node to start searching from or NULL, the node
550 * you pass will not be searched, only the next one
551 * will; typically, you pass what the previous call
552 * returned. of_node_put() will be called on it
553 * @matches: array of of device match structures to search in
555 * Returns a node pointer with refcount incremented, use
556 * of_node_put() on it when done.
558 struct device_node *of_find_matching_node(struct device_node *from,
559 const struct of_device_id *matches)
561 struct device_node *np;
563 read_lock(&devtree_lock);
564 np = from ? from->allnext : allnodes;
565 for (; np; np = np->allnext) {
566 if (of_match_node(matches, np) && of_node_get(np))
570 read_unlock(&devtree_lock);
573 EXPORT_SYMBOL(of_find_matching_node);
576 * of_modalias_node - Lookup appropriate modalias for a device node
577 * @node: pointer to a device tree node
578 * @modalias: Pointer to buffer that modalias value will be copied into
579 * @len: Length of modalias value
581 * Based on the value of the compatible property, this routine will attempt
582 * to choose an appropriate modalias value for a particular device tree node.
583 * It does this by stripping the manufacturer prefix (as delimited by a ',')
584 * from the first entry in the compatible list property.
586 * This routine returns 0 on success, <0 on failure.
588 int of_modalias_node(struct device_node *node, char *modalias, int len)
590 const char *compatible, *p;
593 compatible = of_get_property(node, "compatible", &cplen);
594 if (!compatible || strlen(compatible) > cplen)
596 p = strchr(compatible, ',');
597 strlcpy(modalias, p ? p + 1 : compatible, len);
600 EXPORT_SYMBOL_GPL(of_modalias_node);
603 * of_find_node_by_phandle - Find a node given a phandle
604 * @handle: phandle of the node to find
606 * Returns a node pointer with refcount incremented, use
607 * of_node_put() on it when done.
609 struct device_node *of_find_node_by_phandle(phandle handle)
611 struct device_node *np;
613 read_lock(&devtree_lock);
614 for (np = allnodes; np; np = np->allnext)
615 if (np->phandle == handle)
618 read_unlock(&devtree_lock);
621 EXPORT_SYMBOL(of_find_node_by_phandle);
624 * of_property_read_u32_array - Find and read an array of 32 bit integers
627 * @np: device node from which the property value is to be read.
628 * @propname: name of the property to be searched.
629 * @out_value: pointer to return value, modified only if return value is 0.
631 * Search for a property in a device node and read 32-bit value(s) from
632 * it. Returns 0 on success, -EINVAL if the property does not exist,
633 * -ENODATA if property does not have a value, and -EOVERFLOW if the
634 * property data isn't large enough.
636 * The out_value is modified only if a valid u32 value can be decoded.
638 int of_property_read_u32_array(const struct device_node *np,
639 const char *propname, u32 *out_values,
642 struct property *prop = of_find_property(np, propname, NULL);
649 if ((sz * sizeof(*out_values)) > prop->length)
654 *out_values++ = be32_to_cpup(val++);
657 EXPORT_SYMBOL_GPL(of_property_read_u32_array);
660 * of_property_read_u64 - Find and read a 64 bit integer from a property
661 * @np: device node from which the property value is to be read.
662 * @propname: name of the property to be searched.
663 * @out_value: pointer to return value, modified only if return value is 0.
665 * Search for a property in a device node and read a 64-bit value from
666 * it. Returns 0 on success, -EINVAL if the property does not exist,
667 * -ENODATA if property does not have a value, and -EOVERFLOW if the
668 * property data isn't large enough.
670 * The out_value is modified only if a valid u64 value can be decoded.
672 int of_property_read_u64(const struct device_node *np, const char *propname,
675 struct property *prop = of_find_property(np, propname, NULL);
681 if (sizeof(*out_value) > prop->length)
683 *out_value = of_read_number(prop->value, 2);
686 EXPORT_SYMBOL_GPL(of_property_read_u64);
689 * of_property_read_string - Find and read a string from a property
690 * @np: device node from which the property value is to be read.
691 * @propname: name of the property to be searched.
692 * @out_string: pointer to null terminated return string, modified only if
695 * Search for a property in a device tree node and retrieve a null
696 * terminated string value (pointer to data, not a copy). Returns 0 on
697 * success, -EINVAL if the property does not exist, -ENODATA if property
698 * does not have a value, and -EILSEQ if the string is not null-terminated
699 * within the length of the property data.
701 * The out_string pointer is modified only if a valid string can be decoded.
703 int of_property_read_string(struct device_node *np, const char *propname,
704 const char **out_string)
706 struct property *prop = of_find_property(np, propname, NULL);
711 if (strnlen(prop->value, prop->length) >= prop->length)
713 *out_string = prop->value;
716 EXPORT_SYMBOL_GPL(of_property_read_string);
719 * of_property_read_string_index - Find and read a string from a multiple
721 * @np: device node from which the property value is to be read.
722 * @propname: name of the property to be searched.
723 * @index: index of the string in the list of strings
724 * @out_string: pointer to null terminated return string, modified only if
727 * Search for a property in a device tree node and retrieve a null
728 * terminated string value (pointer to data, not a copy) in the list of strings
729 * contained in that property.
730 * Returns 0 on success, -EINVAL if the property does not exist, -ENODATA if
731 * property does not have a value, and -EILSEQ if the string is not
732 * null-terminated within the length of the property data.
734 * The out_string pointer is modified only if a valid string can be decoded.
736 int of_property_read_string_index(struct device_node *np, const char *propname,
737 int index, const char **output)
739 struct property *prop = of_find_property(np, propname, NULL);
741 size_t l = 0, total = 0;
748 if (strnlen(prop->value, prop->length) >= prop->length)
753 for (i = 0; total < prop->length; total += l, p += l) {
762 EXPORT_SYMBOL_GPL(of_property_read_string_index);
766 * of_property_count_strings - Find and return the number of strings from a
767 * multiple strings property.
768 * @np: device node from which the property value is to be read.
769 * @propname: name of the property to be searched.
771 * Search for a property in a device tree node and retrieve the number of null
772 * terminated string contain in it. Returns the number of strings on
773 * success, -EINVAL if the property does not exist, -ENODATA if property
774 * does not have a value, and -EILSEQ if the string is not null-terminated
775 * within the length of the property data.
777 int of_property_count_strings(struct device_node *np, const char *propname)
779 struct property *prop = of_find_property(np, propname, NULL);
781 size_t l = 0, total = 0;
788 if (strnlen(prop->value, prop->length) >= prop->length)
793 for (i = 0; total < prop->length; total += l, p += l, i++)
798 EXPORT_SYMBOL_GPL(of_property_count_strings);
801 * of_parse_phandle - Resolve a phandle property to a device_node pointer
802 * @np: Pointer to device node holding phandle property
803 * @phandle_name: Name of property holding a phandle value
804 * @index: For properties holding a table of phandles, this is the index into
807 * Returns the device_node pointer with refcount incremented. Use
808 * of_node_put() on it when done.
811 of_parse_phandle(struct device_node *np, const char *phandle_name, int index)
813 const __be32 *phandle;
816 phandle = of_get_property(np, phandle_name, &size);
817 if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
820 return of_find_node_by_phandle(be32_to_cpup(phandle + index));
822 EXPORT_SYMBOL(of_parse_phandle);
825 * of_parse_phandles_with_args - Find a node pointed by phandle in a list
826 * @np: pointer to a device tree node containing a list
827 * @list_name: property name that contains a list
828 * @cells_name: property name that specifies phandles' arguments count
829 * @index: index of a phandle to parse out
830 * @out_node: optional pointer to device_node struct pointer (will be filled)
831 * @out_args: optional pointer to arguments pointer (will be filled)
833 * This function is useful to parse lists of phandles and their arguments.
834 * Returns 0 on success and fills out_node and out_args, on error returns
835 * appropriate errno value.
848 * list = <&phandle1 1 2 &phandle2 3>;
851 * To get a device_node of the `node2' node you may call this:
852 * of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args);
854 int of_parse_phandles_with_args(struct device_node *np, const char *list_name,
855 const char *cells_name, int index,
856 struct device_node **out_node,
857 const void **out_args)
861 const __be32 *list_end;
864 struct device_node *node = NULL;
865 const void *args = NULL;
867 list = of_get_property(np, list_name, &size);
872 list_end = list + size / sizeof(*list);
874 while (list < list_end) {
878 phandle = be32_to_cpup(list++);
881 /* one cell hole in the list = <>; */
885 node = of_find_node_by_phandle(phandle);
887 pr_debug("%s: could not find phandle\n",
892 cells = of_get_property(node, cells_name, &size);
893 if (!cells || size != sizeof(*cells)) {
894 pr_debug("%s: could not get %s for %s\n",
895 np->full_name, cells_name, node->full_name);
899 list += be32_to_cpup(cells);
900 if (list > list_end) {
901 pr_debug("%s: insufficient arguments length\n",
906 if (cur_index == index)
917 * args w/o node indicates that the loop above has stopped at
918 * the 'hole' cell. Report this differently.
936 pr_debug("%s failed with status %d\n", __func__, ret);
939 EXPORT_SYMBOL(of_parse_phandles_with_args);
942 * prom_add_property - Add a property to a node
944 int prom_add_property(struct device_node *np, struct property *prop)
946 struct property **next;
950 write_lock_irqsave(&devtree_lock, flags);
951 next = &np->properties;
953 if (strcmp(prop->name, (*next)->name) == 0) {
954 /* duplicate ! don't insert it */
955 write_unlock_irqrestore(&devtree_lock, flags);
958 next = &(*next)->next;
961 write_unlock_irqrestore(&devtree_lock, flags);
963 #ifdef CONFIG_PROC_DEVICETREE
964 /* try to add to proc as well if it was initialized */
966 proc_device_tree_add_prop(np->pde, prop);
967 #endif /* CONFIG_PROC_DEVICETREE */
973 * prom_remove_property - Remove a property from a node.
975 * Note that we don't actually remove it, since we have given out
976 * who-knows-how-many pointers to the data using get-property.
977 * Instead we just move the property to the "dead properties"
978 * list, so it won't be found any more.
980 int prom_remove_property(struct device_node *np, struct property *prop)
982 struct property **next;
986 write_lock_irqsave(&devtree_lock, flags);
987 next = &np->properties;
992 prop->next = np->deadprops;
993 np->deadprops = prop;
997 next = &(*next)->next;
999 write_unlock_irqrestore(&devtree_lock, flags);
1004 #ifdef CONFIG_PROC_DEVICETREE
1005 /* try to remove the proc node as well */
1007 proc_device_tree_remove_prop(np->pde, prop);
1008 #endif /* CONFIG_PROC_DEVICETREE */
1014 * prom_update_property - Update a property in a node.
1016 * Note that we don't actually remove it, since we have given out
1017 * who-knows-how-many pointers to the data using get-property.
1018 * Instead we just move the property to the "dead properties" list,
1019 * and add the new property to the property list
1021 int prom_update_property(struct device_node *np,
1022 struct property *newprop,
1023 struct property *oldprop)
1025 struct property **next;
1026 unsigned long flags;
1029 write_lock_irqsave(&devtree_lock, flags);
1030 next = &np->properties;
1032 if (*next == oldprop) {
1033 /* found the node */
1034 newprop->next = oldprop->next;
1036 oldprop->next = np->deadprops;
1037 np->deadprops = oldprop;
1041 next = &(*next)->next;
1043 write_unlock_irqrestore(&devtree_lock, flags);
1048 #ifdef CONFIG_PROC_DEVICETREE
1049 /* try to add to proc as well if it was initialized */
1051 proc_device_tree_update_prop(np->pde, newprop, oldprop);
1052 #endif /* CONFIG_PROC_DEVICETREE */
1057 #if defined(CONFIG_OF_DYNAMIC)
1059 * Support for dynamic device trees.
1061 * On some platforms, the device tree can be manipulated at runtime.
1062 * The routines in this section support adding, removing and changing
1063 * device tree nodes.
1067 * of_attach_node - Plug a device node into the tree and global list.
1069 void of_attach_node(struct device_node *np)
1071 unsigned long flags;
1073 write_lock_irqsave(&devtree_lock, flags);
1074 np->sibling = np->parent->child;
1075 np->allnext = allnodes;
1076 np->parent->child = np;
1078 write_unlock_irqrestore(&devtree_lock, flags);
1082 * of_detach_node - "Unplug" a node from the device tree.
1084 * The caller must hold a reference to the node. The memory associated with
1085 * the node is not freed until its refcount goes to zero.
1087 void of_detach_node(struct device_node *np)
1089 struct device_node *parent;
1090 unsigned long flags;
1092 write_lock_irqsave(&devtree_lock, flags);
1094 parent = np->parent;
1099 allnodes = np->allnext;
1101 struct device_node *prev;
1102 for (prev = allnodes;
1103 prev->allnext != np;
1104 prev = prev->allnext)
1106 prev->allnext = np->allnext;
1109 if (parent->child == np)
1110 parent->child = np->sibling;
1112 struct device_node *prevsib;
1113 for (prevsib = np->parent->child;
1114 prevsib->sibling != np;
1115 prevsib = prevsib->sibling)
1117 prevsib->sibling = np->sibling;
1120 of_node_set_flag(np, OF_DETACHED);
1123 write_unlock_irqrestore(&devtree_lock, flags);
1125 #endif /* defined(CONFIG_OF_DYNAMIC) */
1127 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1128 int id, const char *stem, int stem_len)
1132 strncpy(ap->stem, stem, stem_len);
1133 ap->stem[stem_len] = 0;
1134 list_add_tail(&ap->link, &aliases_lookup);
1135 pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
1136 ap->alias, ap->stem, ap->id, np ? np->full_name : NULL);
1140 * of_alias_scan - Scan all properties of 'aliases' node
1142 * The function scans all the properties of 'aliases' node and populate
1143 * the the global lookup table with the properties. It returns the
1144 * number of alias_prop found, or error code in error case.
1146 * @dt_alloc: An allocator that provides a virtual address to memory
1147 * for the resulting tree
1149 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1151 struct property *pp;
1153 of_chosen = of_find_node_by_path("/chosen");
1154 if (of_chosen == NULL)
1155 of_chosen = of_find_node_by_path("/chosen@0");
1156 of_aliases = of_find_node_by_path("/aliases");
1160 for_each_property_of_node(of_aliases, pp) {
1161 const char *start = pp->name;
1162 const char *end = start + strlen(start);
1163 struct device_node *np;
1164 struct alias_prop *ap;
1167 /* Skip those we do not want to proceed */
1168 if (!strcmp(pp->name, "name") ||
1169 !strcmp(pp->name, "phandle") ||
1170 !strcmp(pp->name, "linux,phandle"))
1173 np = of_find_node_by_path(pp->value);
1177 /* walk the alias backwards to extract the id and work out
1178 * the 'stem' string */
1179 while (isdigit(*(end-1)) && end > start)
1183 if (kstrtoint(end, 10, &id) < 0)
1186 /* Allocate an alias_prop with enough space for the stem */
1187 ap = dt_alloc(sizeof(*ap) + len + 1, 4);
1191 of_alias_add(ap, np, id, start, len);
1196 * of_alias_get_id - Get alias id for the given device_node
1197 * @np: Pointer to the given device_node
1198 * @stem: Alias stem of the given device_node
1200 * The function travels the lookup table to get alias id for the given
1201 * device_node and alias stem. It returns the alias id if find it.
1203 int of_alias_get_id(struct device_node *np, const char *stem)
1205 struct alias_prop *app;
1208 mutex_lock(&of_aliases_mutex);
1209 list_for_each_entry(app, &aliases_lookup, link) {
1210 if (strcmp(app->stem, stem) != 0)
1213 if (np == app->np) {
1218 mutex_unlock(&of_aliases_mutex);
1222 EXPORT_SYMBOL_GPL(of_alias_get_id);