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/cpu.h>
22 #include <linux/module.h>
24 #include <linux/spinlock.h>
25 #include <linux/slab.h>
26 #include <linux/proc_fs.h>
28 #include "of_private.h"
30 LIST_HEAD(aliases_lookup);
32 struct device_node *of_allnodes;
33 EXPORT_SYMBOL(of_allnodes);
34 struct device_node *of_chosen;
35 struct device_node *of_aliases;
36 static struct device_node *of_stdout;
38 DEFINE_MUTEX(of_aliases_mutex);
40 /* use when traversing tree through the allnext, child, sibling,
41 * or parent members of struct device_node.
43 DEFINE_RAW_SPINLOCK(devtree_lock);
45 int of_n_addr_cells(struct device_node *np)
52 ip = of_get_property(np, "#address-cells", NULL);
54 return be32_to_cpup(ip);
56 /* No #address-cells property for the root node */
57 return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
59 EXPORT_SYMBOL(of_n_addr_cells);
61 int of_n_size_cells(struct device_node *np)
68 ip = of_get_property(np, "#size-cells", NULL);
70 return be32_to_cpup(ip);
72 /* No #size-cells property for the root node */
73 return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
75 EXPORT_SYMBOL(of_n_size_cells);
78 int __weak of_node_to_nid(struct device_node *np)
80 return numa_node_id();
84 #if defined(CONFIG_OF_DYNAMIC)
86 * of_node_get - Increment refcount of a node
87 * @node: Node to inc refcount, NULL is supported to
88 * simplify writing of callers
92 struct device_node *of_node_get(struct device_node *node)
95 kref_get(&node->kref);
98 EXPORT_SYMBOL(of_node_get);
100 static inline struct device_node *kref_to_device_node(struct kref *kref)
102 return container_of(kref, struct device_node, kref);
106 * of_node_release - release a dynamically allocated node
107 * @kref: kref element of the node to be released
109 * In of_node_put() this function is passed to kref_put()
112 static void of_node_release(struct kref *kref)
114 struct device_node *node = kref_to_device_node(kref);
115 struct property *prop = node->properties;
117 /* We should never be releasing nodes that haven't been detached. */
118 if (!of_node_check_flag(node, OF_DETACHED)) {
119 pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name);
121 kref_init(&node->kref);
125 if (!of_node_check_flag(node, OF_DYNAMIC))
129 struct property *next = prop->next;
136 prop = node->deadprops;
137 node->deadprops = NULL;
140 kfree(node->full_name);
146 * of_node_put - Decrement refcount of a node
147 * @node: Node to dec refcount, NULL is supported to
148 * simplify writing of callers
151 void of_node_put(struct device_node *node)
154 kref_put(&node->kref, of_node_release);
156 EXPORT_SYMBOL(of_node_put);
157 #endif /* CONFIG_OF_DYNAMIC */
159 static struct property *__of_find_property(const struct device_node *np,
160 const char *name, int *lenp)
167 for (pp = np->properties; pp; pp = pp->next) {
168 if (of_prop_cmp(pp->name, name) == 0) {
178 struct property *of_find_property(const struct device_node *np,
185 raw_spin_lock_irqsave(&devtree_lock, flags);
186 pp = __of_find_property(np, name, lenp);
187 raw_spin_unlock_irqrestore(&devtree_lock, flags);
191 EXPORT_SYMBOL(of_find_property);
194 * of_find_all_nodes - Get next node in global list
195 * @prev: Previous node or NULL to start iteration
196 * of_node_put() will be called on it
198 * Returns a node pointer with refcount incremented, use
199 * of_node_put() on it when done.
201 struct device_node *of_find_all_nodes(struct device_node *prev)
203 struct device_node *np;
206 raw_spin_lock_irqsave(&devtree_lock, flags);
207 np = prev ? prev->allnext : of_allnodes;
208 for (; np != NULL; np = np->allnext)
212 raw_spin_unlock_irqrestore(&devtree_lock, flags);
215 EXPORT_SYMBOL(of_find_all_nodes);
218 * Find a property with a given name for a given node
219 * and return the value.
221 static const void *__of_get_property(const struct device_node *np,
222 const char *name, int *lenp)
224 struct property *pp = __of_find_property(np, name, lenp);
226 return pp ? pp->value : NULL;
230 * Find a property with a given name for a given node
231 * and return the value.
233 const void *of_get_property(const struct device_node *np, const char *name,
236 struct property *pp = of_find_property(np, name, lenp);
238 return pp ? pp->value : NULL;
240 EXPORT_SYMBOL(of_get_property);
243 * arch_match_cpu_phys_id - Match the given logical CPU and physical id
245 * @cpu: logical cpu index of a core/thread
246 * @phys_id: physical identifier of a core/thread
248 * CPU logical to physical index mapping is architecture specific.
249 * However this __weak function provides a default match of physical
250 * id to logical cpu index. phys_id provided here is usually values read
251 * from the device tree which must match the hardware internal registers.
253 * Returns true if the physical identifier and the logical cpu index
254 * correspond to the same core/thread, false otherwise.
256 bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id)
258 return (u32)phys_id == cpu;
262 * Checks if the given "prop_name" property holds the physical id of the
263 * core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not
264 * NULL, local thread number within the core is returned in it.
266 static bool __of_find_n_match_cpu_property(struct device_node *cpun,
267 const char *prop_name, int cpu, unsigned int *thread)
270 int ac, prop_len, tid;
273 ac = of_n_addr_cells(cpun);
274 cell = of_get_property(cpun, prop_name, &prop_len);
277 prop_len /= sizeof(*cell) * ac;
278 for (tid = 0; tid < prop_len; tid++) {
279 hwid = of_read_number(cell, ac);
280 if (arch_match_cpu_phys_id(cpu, hwid)) {
291 * arch_find_n_match_cpu_physical_id - See if the given device node is
292 * for the cpu corresponding to logical cpu 'cpu'. Return true if so,
293 * else false. If 'thread' is non-NULL, the local thread number within the
294 * core is returned in it.
296 bool __weak arch_find_n_match_cpu_physical_id(struct device_node *cpun,
297 int cpu, unsigned int *thread)
299 /* Check for non-standard "ibm,ppc-interrupt-server#s" property
300 * for thread ids on PowerPC. If it doesn't exist fallback to
301 * standard "reg" property.
303 if (IS_ENABLED(CONFIG_PPC) &&
304 __of_find_n_match_cpu_property(cpun,
305 "ibm,ppc-interrupt-server#s",
309 if (__of_find_n_match_cpu_property(cpun, "reg", cpu, thread))
316 * of_get_cpu_node - Get device node associated with the given logical CPU
318 * @cpu: CPU number(logical index) for which device node is required
319 * @thread: if not NULL, local thread number within the physical core is
322 * The main purpose of this function is to retrieve the device node for the
323 * given logical CPU index. It should be used to initialize the of_node in
324 * cpu device. Once of_node in cpu device is populated, all the further
325 * references can use that instead.
327 * CPU logical to physical index mapping is architecture specific and is built
328 * before booting secondary cores. This function uses arch_match_cpu_phys_id
329 * which can be overridden by architecture specific implementation.
331 * Returns a node pointer for the logical cpu if found, else NULL.
333 struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
335 struct device_node *cpun;
337 for_each_node_by_type(cpun, "cpu") {
338 if (arch_find_n_match_cpu_physical_id(cpun, cpu, thread))
343 EXPORT_SYMBOL(of_get_cpu_node);
345 /** Checks if the given "compat" string matches one of the strings in
346 * the device's "compatible" property
348 static int __of_device_is_compatible(const struct device_node *device,
354 cp = __of_get_property(device, "compatible", &cplen);
358 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
368 /** Checks if the given "compat" string matches one of the strings in
369 * the device's "compatible" property
371 int of_device_is_compatible(const struct device_node *device,
377 raw_spin_lock_irqsave(&devtree_lock, flags);
378 res = __of_device_is_compatible(device, compat);
379 raw_spin_unlock_irqrestore(&devtree_lock, flags);
382 EXPORT_SYMBOL(of_device_is_compatible);
385 * of_machine_is_compatible - Test root of device tree for a given compatible value
386 * @compat: compatible string to look for in root node's compatible property.
388 * Returns true if the root node has the given value in its
389 * compatible property.
391 int of_machine_is_compatible(const char *compat)
393 struct device_node *root;
396 root = of_find_node_by_path("/");
398 rc = of_device_is_compatible(root, compat);
403 EXPORT_SYMBOL(of_machine_is_compatible);
406 * __of_device_is_available - check if a device is available for use
408 * @device: Node to check for availability, with locks already held
410 * Returns 1 if the status property is absent or set to "okay" or "ok",
413 static int __of_device_is_available(const struct device_node *device)
418 status = __of_get_property(device, "status", &statlen);
423 if (!strcmp(status, "okay") || !strcmp(status, "ok"))
431 * of_device_is_available - check if a device is available for use
433 * @device: Node to check for availability
435 * Returns 1 if the status property is absent or set to "okay" or "ok",
438 int of_device_is_available(const struct device_node *device)
443 raw_spin_lock_irqsave(&devtree_lock, flags);
444 res = __of_device_is_available(device);
445 raw_spin_unlock_irqrestore(&devtree_lock, flags);
449 EXPORT_SYMBOL(of_device_is_available);
452 * of_get_parent - Get a node's parent if any
453 * @node: Node to get parent
455 * Returns a node pointer with refcount incremented, use
456 * of_node_put() on it when done.
458 struct device_node *of_get_parent(const struct device_node *node)
460 struct device_node *np;
466 raw_spin_lock_irqsave(&devtree_lock, flags);
467 np = of_node_get(node->parent);
468 raw_spin_unlock_irqrestore(&devtree_lock, flags);
471 EXPORT_SYMBOL(of_get_parent);
474 * of_get_next_parent - Iterate to a node's parent
475 * @node: Node to get parent of
477 * This is like of_get_parent() except that it drops the
478 * refcount on the passed node, making it suitable for iterating
479 * through a node's parents.
481 * Returns a node pointer with refcount incremented, use
482 * of_node_put() on it when done.
484 struct device_node *of_get_next_parent(struct device_node *node)
486 struct device_node *parent;
492 raw_spin_lock_irqsave(&devtree_lock, flags);
493 parent = of_node_get(node->parent);
495 raw_spin_unlock_irqrestore(&devtree_lock, flags);
498 EXPORT_SYMBOL(of_get_next_parent);
501 * of_get_next_child - Iterate a node childs
503 * @prev: previous child of the parent node, or NULL to get first
505 * Returns a node pointer with refcount incremented, use
506 * of_node_put() on it when done.
508 struct device_node *of_get_next_child(const struct device_node *node,
509 struct device_node *prev)
511 struct device_node *next;
514 raw_spin_lock_irqsave(&devtree_lock, flags);
515 next = prev ? prev->sibling : node->child;
516 for (; next; next = next->sibling)
517 if (of_node_get(next))
520 raw_spin_unlock_irqrestore(&devtree_lock, flags);
523 EXPORT_SYMBOL(of_get_next_child);
526 * of_get_next_available_child - Find the next available child node
528 * @prev: previous child of the parent node, or NULL to get first
530 * This function is like of_get_next_child(), except that it
531 * automatically skips any disabled nodes (i.e. status = "disabled").
533 struct device_node *of_get_next_available_child(const struct device_node *node,
534 struct device_node *prev)
536 struct device_node *next;
539 raw_spin_lock_irqsave(&devtree_lock, flags);
540 next = prev ? prev->sibling : node->child;
541 for (; next; next = next->sibling) {
542 if (!__of_device_is_available(next))
544 if (of_node_get(next))
548 raw_spin_unlock_irqrestore(&devtree_lock, flags);
551 EXPORT_SYMBOL(of_get_next_available_child);
554 * of_get_child_by_name - Find the child node by name for a given parent
556 * @name: child name to look for.
558 * This function looks for child node for given matching name
560 * Returns a node pointer if found, with refcount incremented, use
561 * of_node_put() on it when done.
562 * Returns NULL if node is not found.
564 struct device_node *of_get_child_by_name(const struct device_node *node,
567 struct device_node *child;
569 for_each_child_of_node(node, child)
570 if (child->name && (of_node_cmp(child->name, name) == 0))
574 EXPORT_SYMBOL(of_get_child_by_name);
577 * of_find_node_by_path - Find a node matching a full OF path
578 * @path: The full path to match
580 * Returns a node pointer with refcount incremented, use
581 * of_node_put() on it when done.
583 struct device_node *of_find_node_by_path(const char *path)
585 struct device_node *np = of_allnodes;
588 raw_spin_lock_irqsave(&devtree_lock, flags);
589 for (; np; np = np->allnext) {
590 if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
594 raw_spin_unlock_irqrestore(&devtree_lock, flags);
597 EXPORT_SYMBOL(of_find_node_by_path);
600 * of_find_node_by_name - Find a node by its "name" property
601 * @from: The node to start searching from or NULL, the node
602 * you pass will not be searched, only the next one
603 * will; typically, you pass what the previous call
604 * returned. of_node_put() will be called on it
605 * @name: The name string to match against
607 * Returns a node pointer with refcount incremented, use
608 * of_node_put() on it when done.
610 struct device_node *of_find_node_by_name(struct device_node *from,
613 struct device_node *np;
616 raw_spin_lock_irqsave(&devtree_lock, flags);
617 np = from ? from->allnext : of_allnodes;
618 for (; np; np = np->allnext)
619 if (np->name && (of_node_cmp(np->name, name) == 0)
623 raw_spin_unlock_irqrestore(&devtree_lock, flags);
626 EXPORT_SYMBOL(of_find_node_by_name);
629 * of_find_node_by_type - Find a node by its "device_type" property
630 * @from: The node to start searching from, or NULL to start searching
631 * the entire device tree. The node you pass will not be
632 * searched, only the next one will; typically, you pass
633 * what the previous call returned. of_node_put() will be
634 * called on from for you.
635 * @type: The type string to match against
637 * Returns a node pointer with refcount incremented, use
638 * of_node_put() on it when done.
640 struct device_node *of_find_node_by_type(struct device_node *from,
643 struct device_node *np;
646 raw_spin_lock_irqsave(&devtree_lock, flags);
647 np = from ? from->allnext : of_allnodes;
648 for (; np; np = np->allnext)
649 if (np->type && (of_node_cmp(np->type, type) == 0)
653 raw_spin_unlock_irqrestore(&devtree_lock, flags);
656 EXPORT_SYMBOL(of_find_node_by_type);
659 * of_find_compatible_node - Find a node based on type and one of the
660 * tokens in its "compatible" property
661 * @from: The node to start searching from or NULL, the node
662 * you pass will not be searched, only the next one
663 * will; typically, you pass what the previous call
664 * returned. of_node_put() will be called on it
665 * @type: The type string to match "device_type" or NULL to ignore
666 * @compatible: The string to match to one of the tokens in the device
669 * Returns a node pointer with refcount incremented, use
670 * of_node_put() on it when done.
672 struct device_node *of_find_compatible_node(struct device_node *from,
673 const char *type, const char *compatible)
675 struct device_node *np;
678 raw_spin_lock_irqsave(&devtree_lock, flags);
679 np = from ? from->allnext : of_allnodes;
680 for (; np; np = np->allnext) {
682 && !(np->type && (of_node_cmp(np->type, type) == 0)))
684 if (__of_device_is_compatible(np, compatible) &&
689 raw_spin_unlock_irqrestore(&devtree_lock, flags);
692 EXPORT_SYMBOL(of_find_compatible_node);
695 * of_find_node_with_property - Find a node which has a property with
697 * @from: The node to start searching from or NULL, the node
698 * you pass will not be searched, only the next one
699 * will; typically, you pass what the previous call
700 * returned. of_node_put() will be called on it
701 * @prop_name: The name of the property to look for.
703 * Returns a node pointer with refcount incremented, use
704 * of_node_put() on it when done.
706 struct device_node *of_find_node_with_property(struct device_node *from,
707 const char *prop_name)
709 struct device_node *np;
713 raw_spin_lock_irqsave(&devtree_lock, flags);
714 np = from ? from->allnext : of_allnodes;
715 for (; np; np = np->allnext) {
716 for (pp = np->properties; pp; pp = pp->next) {
717 if (of_prop_cmp(pp->name, prop_name) == 0) {
725 raw_spin_unlock_irqrestore(&devtree_lock, flags);
728 EXPORT_SYMBOL(of_find_node_with_property);
731 const struct of_device_id *__of_match_node(const struct of_device_id *matches,
732 const struct device_node *node)
737 while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
739 if (matches->name[0])
741 && !strcmp(matches->name, node->name);
742 if (matches->type[0])
744 && !strcmp(matches->type, node->type);
745 if (matches->compatible[0])
746 match &= __of_device_is_compatible(node,
747 matches->compatible);
756 * of_match_node - Tell if an device_node has a matching of_match structure
757 * @matches: array of of device match structures to search in
758 * @node: the of device structure to match against
760 * Low level utility function used by device matching.
762 const struct of_device_id *of_match_node(const struct of_device_id *matches,
763 const struct device_node *node)
765 const struct of_device_id *match;
768 raw_spin_lock_irqsave(&devtree_lock, flags);
769 match = __of_match_node(matches, node);
770 raw_spin_unlock_irqrestore(&devtree_lock, flags);
773 EXPORT_SYMBOL(of_match_node);
776 * of_find_matching_node_and_match - Find a node based on an of_device_id
778 * @from: The node to start searching from or NULL, the node
779 * you pass will not be searched, only the next one
780 * will; typically, you pass what the previous call
781 * returned. of_node_put() will be called on it
782 * @matches: array of of device match structures to search in
783 * @match Updated to point at the matches entry which matched
785 * Returns a node pointer with refcount incremented, use
786 * of_node_put() on it when done.
788 struct device_node *of_find_matching_node_and_match(struct device_node *from,
789 const struct of_device_id *matches,
790 const struct of_device_id **match)
792 struct device_node *np;
793 const struct of_device_id *m;
799 raw_spin_lock_irqsave(&devtree_lock, flags);
800 np = from ? from->allnext : of_allnodes;
801 for (; np; np = np->allnext) {
802 m = __of_match_node(matches, np);
803 if (m && of_node_get(np)) {
810 raw_spin_unlock_irqrestore(&devtree_lock, flags);
813 EXPORT_SYMBOL(of_find_matching_node_and_match);
816 * of_modalias_node - Lookup appropriate modalias for a device node
817 * @node: pointer to a device tree node
818 * @modalias: Pointer to buffer that modalias value will be copied into
819 * @len: Length of modalias value
821 * Based on the value of the compatible property, this routine will attempt
822 * to choose an appropriate modalias value for a particular device tree node.
823 * It does this by stripping the manufacturer prefix (as delimited by a ',')
824 * from the first entry in the compatible list property.
826 * This routine returns 0 on success, <0 on failure.
828 int of_modalias_node(struct device_node *node, char *modalias, int len)
830 const char *compatible, *p;
833 compatible = of_get_property(node, "compatible", &cplen);
834 if (!compatible || strlen(compatible) > cplen)
836 p = strchr(compatible, ',');
837 strlcpy(modalias, p ? p + 1 : compatible, len);
840 EXPORT_SYMBOL_GPL(of_modalias_node);
843 * of_find_node_by_phandle - Find a node given a phandle
844 * @handle: phandle of the node to find
846 * Returns a node pointer with refcount incremented, use
847 * of_node_put() on it when done.
849 struct device_node *of_find_node_by_phandle(phandle handle)
851 struct device_node *np;
854 raw_spin_lock_irqsave(&devtree_lock, flags);
855 for (np = of_allnodes; np; np = np->allnext)
856 if (np->phandle == handle)
859 raw_spin_unlock_irqrestore(&devtree_lock, flags);
862 EXPORT_SYMBOL(of_find_node_by_phandle);
865 * of_find_property_value_of_size
867 * @np: device node from which the property value is to be read.
868 * @propname: name of the property to be searched.
869 * @len: requested length of property value
871 * Search for a property in a device node and valid the requested size.
872 * Returns the property value on success, -EINVAL if the property does not
873 * exist, -ENODATA if property does not have a value, and -EOVERFLOW if the
874 * property data isn't large enough.
877 static void *of_find_property_value_of_size(const struct device_node *np,
878 const char *propname, u32 len)
880 struct property *prop = of_find_property(np, propname, NULL);
883 return ERR_PTR(-EINVAL);
885 return ERR_PTR(-ENODATA);
886 if (len > prop->length)
887 return ERR_PTR(-EOVERFLOW);
893 * of_property_read_u32_index - Find and read a u32 from a multi-value property.
895 * @np: device node from which the property value is to be read.
896 * @propname: name of the property to be searched.
897 * @index: index of the u32 in the list of values
898 * @out_value: pointer to return value, modified only if no error.
900 * Search for a property in a device node and read nth 32-bit value from
901 * it. Returns 0 on success, -EINVAL if the property does not exist,
902 * -ENODATA if property does not have a value, and -EOVERFLOW if the
903 * property data isn't large enough.
905 * The out_value is modified only if a valid u32 value can be decoded.
907 int of_property_read_u32_index(const struct device_node *np,
908 const char *propname,
909 u32 index, u32 *out_value)
911 const u32 *val = of_find_property_value_of_size(np, propname,
912 ((index + 1) * sizeof(*out_value)));
917 *out_value = be32_to_cpup(((__be32 *)val) + index);
920 EXPORT_SYMBOL_GPL(of_property_read_u32_index);
923 * of_property_read_u8_array - Find and read an array of u8 from a property.
925 * @np: device node from which the property value is to be read.
926 * @propname: name of the property to be searched.
927 * @out_values: pointer to return value, modified only if return value is 0.
928 * @sz: number of array elements to read
930 * Search for a property in a device node and read 8-bit value(s) from
931 * it. Returns 0 on success, -EINVAL if the property does not exist,
932 * -ENODATA if property does not have a value, and -EOVERFLOW if the
933 * property data isn't large enough.
935 * dts entry of array should be like:
936 * property = /bits/ 8 <0x50 0x60 0x70>;
938 * The out_values is modified only if a valid u8 value can be decoded.
940 int of_property_read_u8_array(const struct device_node *np,
941 const char *propname, u8 *out_values, size_t sz)
943 const u8 *val = of_find_property_value_of_size(np, propname,
944 (sz * sizeof(*out_values)));
950 *out_values++ = *val++;
953 EXPORT_SYMBOL_GPL(of_property_read_u8_array);
956 * of_property_read_u16_array - Find and read an array of u16 from a property.
958 * @np: device node from which the property value is to be read.
959 * @propname: name of the property to be searched.
960 * @out_values: pointer to return value, modified only if return value is 0.
961 * @sz: number of array elements to read
963 * Search for a property in a device node and read 16-bit value(s) from
964 * it. Returns 0 on success, -EINVAL if the property does not exist,
965 * -ENODATA if property does not have a value, and -EOVERFLOW if the
966 * property data isn't large enough.
968 * dts entry of array should be like:
969 * property = /bits/ 16 <0x5000 0x6000 0x7000>;
971 * The out_values is modified only if a valid u16 value can be decoded.
973 int of_property_read_u16_array(const struct device_node *np,
974 const char *propname, u16 *out_values, size_t sz)
976 const __be16 *val = of_find_property_value_of_size(np, propname,
977 (sz * sizeof(*out_values)));
983 *out_values++ = be16_to_cpup(val++);
986 EXPORT_SYMBOL_GPL(of_property_read_u16_array);
989 * of_property_read_u32_array - Find and read an array of 32 bit integers
992 * @np: device node from which the property value is to be read.
993 * @propname: name of the property to be searched.
994 * @out_values: pointer to return value, modified only if return value is 0.
995 * @sz: number of array elements to read
997 * Search for a property in a device node and read 32-bit value(s) from
998 * it. Returns 0 on success, -EINVAL if the property does not exist,
999 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1000 * property data isn't large enough.
1002 * The out_values is modified only if a valid u32 value can be decoded.
1004 int of_property_read_u32_array(const struct device_node *np,
1005 const char *propname, u32 *out_values,
1008 const __be32 *val = of_find_property_value_of_size(np, propname,
1009 (sz * sizeof(*out_values)));
1012 return PTR_ERR(val);
1015 *out_values++ = be32_to_cpup(val++);
1018 EXPORT_SYMBOL_GPL(of_property_read_u32_array);
1021 * of_property_read_u64 - Find and read a 64 bit integer from a property
1022 * @np: device node from which the property value is to be read.
1023 * @propname: name of the property to be searched.
1024 * @out_value: pointer to return value, modified only if return value is 0.
1026 * Search for a property in a device node and read a 64-bit value from
1027 * it. Returns 0 on success, -EINVAL if the property does not exist,
1028 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1029 * property data isn't large enough.
1031 * The out_value is modified only if a valid u64 value can be decoded.
1033 int of_property_read_u64(const struct device_node *np, const char *propname,
1036 const __be32 *val = of_find_property_value_of_size(np, propname,
1037 sizeof(*out_value));
1040 return PTR_ERR(val);
1042 *out_value = of_read_number(val, 2);
1045 EXPORT_SYMBOL_GPL(of_property_read_u64);
1048 * of_property_read_string - Find and read a string from a property
1049 * @np: device node from which the property value is to be read.
1050 * @propname: name of the property to be searched.
1051 * @out_string: pointer to null terminated return string, modified only if
1052 * return value is 0.
1054 * Search for a property in a device tree node and retrieve a null
1055 * terminated string value (pointer to data, not a copy). Returns 0 on
1056 * success, -EINVAL if the property does not exist, -ENODATA if property
1057 * does not have a value, and -EILSEQ if the string is not null-terminated
1058 * within the length of the property data.
1060 * The out_string pointer is modified only if a valid string can be decoded.
1062 int of_property_read_string(struct device_node *np, const char *propname,
1063 const char **out_string)
1065 struct property *prop = of_find_property(np, propname, NULL);
1070 if (strnlen(prop->value, prop->length) >= prop->length)
1072 *out_string = prop->value;
1075 EXPORT_SYMBOL_GPL(of_property_read_string);
1078 * of_property_read_string_index - Find and read a string from a multiple
1080 * @np: device node from which the property value is to be read.
1081 * @propname: name of the property to be searched.
1082 * @index: index of the string in the list of strings
1083 * @out_string: pointer to null terminated return string, modified only if
1084 * return value is 0.
1086 * Search for a property in a device tree node and retrieve a null
1087 * terminated string value (pointer to data, not a copy) in the list of strings
1088 * contained in that property.
1089 * Returns 0 on success, -EINVAL if the property does not exist, -ENODATA if
1090 * property does not have a value, and -EILSEQ if the string is not
1091 * null-terminated within the length of the property data.
1093 * The out_string pointer is modified only if a valid string can be decoded.
1095 int of_property_read_string_index(struct device_node *np, const char *propname,
1096 int index, const char **output)
1098 struct property *prop = of_find_property(np, propname, NULL);
1100 size_t l = 0, total = 0;
1107 if (strnlen(prop->value, prop->length) >= prop->length)
1112 for (i = 0; total < prop->length; total += l, p += l) {
1121 EXPORT_SYMBOL_GPL(of_property_read_string_index);
1124 * of_property_match_string() - Find string in a list and return index
1125 * @np: pointer to node containing string list property
1126 * @propname: string list property name
1127 * @string: pointer to string to search for in string list
1129 * This function searches a string list property and returns the index
1130 * of a specific string value.
1132 int of_property_match_string(struct device_node *np, const char *propname,
1135 struct property *prop = of_find_property(np, propname, NULL);
1138 const char *p, *end;
1146 end = p + prop->length;
1148 for (i = 0; p < end; i++, p += l) {
1152 pr_debug("comparing %s with %s\n", string, p);
1153 if (strcmp(string, p) == 0)
1154 return i; /* Found it; return index */
1158 EXPORT_SYMBOL_GPL(of_property_match_string);
1161 * of_property_count_strings - Find and return the number of strings from a
1162 * multiple strings property.
1163 * @np: device node from which the property value is to be read.
1164 * @propname: name of the property to be searched.
1166 * Search for a property in a device tree node and retrieve the number of null
1167 * terminated string contain in it. Returns the number of strings on
1168 * success, -EINVAL if the property does not exist, -ENODATA if property
1169 * does not have a value, and -EILSEQ if the string is not null-terminated
1170 * within the length of the property data.
1172 int of_property_count_strings(struct device_node *np, const char *propname)
1174 struct property *prop = of_find_property(np, propname, NULL);
1176 size_t l = 0, total = 0;
1183 if (strnlen(prop->value, prop->length) >= prop->length)
1188 for (i = 0; total < prop->length; total += l, p += l, i++)
1193 EXPORT_SYMBOL_GPL(of_property_count_strings);
1195 static int __of_parse_phandle_with_args(const struct device_node *np,
1196 const char *list_name,
1197 const char *cells_name,
1198 int cell_count, int index,
1199 struct of_phandle_args *out_args)
1201 const __be32 *list, *list_end;
1202 int rc = 0, size, cur_index = 0;
1204 struct device_node *node = NULL;
1207 /* Retrieve the phandle list property */
1208 list = of_get_property(np, list_name, &size);
1211 list_end = list + size / sizeof(*list);
1213 /* Loop over the phandles until all the requested entry is found */
1214 while (list < list_end) {
1219 * If phandle is 0, then it is an empty entry with no
1220 * arguments. Skip forward to the next entry.
1222 phandle = be32_to_cpup(list++);
1225 * Find the provider node and parse the #*-cells
1226 * property to determine the argument length.
1228 * This is not needed if the cell count is hard-coded
1229 * (i.e. cells_name not set, but cell_count is set),
1230 * except when we're going to return the found node
1233 if (cells_name || cur_index == index) {
1234 node = of_find_node_by_phandle(phandle);
1236 pr_err("%s: could not find phandle\n",
1243 if (of_property_read_u32(node, cells_name,
1245 pr_err("%s: could not get %s for %s\n",
1246 np->full_name, cells_name,
1255 * Make sure that the arguments actually fit in the
1256 * remaining property data length
1258 if (list + count > list_end) {
1259 pr_err("%s: arguments longer than property\n",
1266 * All of the error cases above bail out of the loop, so at
1267 * this point, the parsing is successful. If the requested
1268 * index matches, then fill the out_args structure and return,
1269 * or return -ENOENT for an empty entry.
1272 if (cur_index == index) {
1278 if (WARN_ON(count > MAX_PHANDLE_ARGS))
1279 count = MAX_PHANDLE_ARGS;
1280 out_args->np = node;
1281 out_args->args_count = count;
1282 for (i = 0; i < count; i++)
1283 out_args->args[i] = be32_to_cpup(list++);
1288 /* Found it! return success */
1299 * Unlock node before returning result; will be one of:
1300 * -ENOENT : index is for empty phandle
1301 * -EINVAL : parsing error on data
1302 * [1..n] : Number of phandle (count mode; when index = -1)
1304 rc = index < 0 ? cur_index : -ENOENT;
1312 * of_parse_phandle - Resolve a phandle property to a device_node pointer
1313 * @np: Pointer to device node holding phandle property
1314 * @phandle_name: Name of property holding a phandle value
1315 * @index: For properties holding a table of phandles, this is the index into
1318 * Returns the device_node pointer with refcount incremented. Use
1319 * of_node_put() on it when done.
1321 struct device_node *of_parse_phandle(const struct device_node *np,
1322 const char *phandle_name, int index)
1324 struct of_phandle_args args;
1329 if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0,
1335 EXPORT_SYMBOL(of_parse_phandle);
1338 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
1339 * @np: pointer to a device tree node containing a list
1340 * @list_name: property name that contains a list
1341 * @cells_name: property name that specifies phandles' arguments count
1342 * @index: index of a phandle to parse out
1343 * @out_args: optional pointer to output arguments structure (will be filled)
1345 * This function is useful to parse lists of phandles and their arguments.
1346 * Returns 0 on success and fills out_args, on error returns appropriate
1349 * Caller is responsible to call of_node_put() on the returned out_args->node
1355 * #list-cells = <2>;
1359 * #list-cells = <1>;
1363 * list = <&phandle1 1 2 &phandle2 3>;
1366 * To get a device_node of the `node2' node you may call this:
1367 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
1369 int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
1370 const char *cells_name, int index,
1371 struct of_phandle_args *out_args)
1375 return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
1378 EXPORT_SYMBOL(of_parse_phandle_with_args);
1381 * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
1382 * @np: pointer to a device tree node containing a list
1383 * @list_name: property name that contains a list
1384 * @cell_count: number of argument cells following the phandle
1385 * @index: index of a phandle to parse out
1386 * @out_args: optional pointer to output arguments structure (will be filled)
1388 * This function is useful to parse lists of phandles and their arguments.
1389 * Returns 0 on success and fills out_args, on error returns appropriate
1392 * Caller is responsible to call of_node_put() on the returned out_args->node
1404 * list = <&phandle1 0 2 &phandle2 2 3>;
1407 * To get a device_node of the `node2' node you may call this:
1408 * of_parse_phandle_with_fixed_args(node3, "list", 2, 1, &args);
1410 int of_parse_phandle_with_fixed_args(const struct device_node *np,
1411 const char *list_name, int cell_count,
1412 int index, struct of_phandle_args *out_args)
1416 return __of_parse_phandle_with_args(np, list_name, NULL, cell_count,
1419 EXPORT_SYMBOL(of_parse_phandle_with_fixed_args);
1422 * of_count_phandle_with_args() - Find the number of phandles references in a property
1423 * @np: pointer to a device tree node containing a list
1424 * @list_name: property name that contains a list
1425 * @cells_name: property name that specifies phandles' arguments count
1427 * Returns the number of phandle + argument tuples within a property. It
1428 * is a typical pattern to encode a list of phandle and variable
1429 * arguments into a single property. The number of arguments is encoded
1430 * by a property in the phandle-target node. For example, a gpios
1431 * property would contain a list of GPIO specifies consisting of a
1432 * phandle and 1 or more arguments. The number of arguments are
1433 * determined by the #gpio-cells property in the node pointed to by the
1436 int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
1437 const char *cells_name)
1439 return __of_parse_phandle_with_args(np, list_name, cells_name, 0, -1,
1442 EXPORT_SYMBOL(of_count_phandle_with_args);
1444 #if defined(CONFIG_OF_DYNAMIC)
1445 static int of_property_notify(int action, struct device_node *np,
1446 struct property *prop)
1448 struct of_prop_reconfig pr;
1452 return of_reconfig_notify(action, &pr);
1455 static int of_property_notify(int action, struct device_node *np,
1456 struct property *prop)
1463 * of_add_property - Add a property to a node
1465 int of_add_property(struct device_node *np, struct property *prop)
1467 struct property **next;
1468 unsigned long flags;
1471 rc = of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop);
1476 raw_spin_lock_irqsave(&devtree_lock, flags);
1477 next = &np->properties;
1479 if (strcmp(prop->name, (*next)->name) == 0) {
1480 /* duplicate ! don't insert it */
1481 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1484 next = &(*next)->next;
1487 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1489 #ifdef CONFIG_PROC_DEVICETREE
1490 /* try to add to proc as well if it was initialized */
1492 proc_device_tree_add_prop(np->pde, prop);
1493 #endif /* CONFIG_PROC_DEVICETREE */
1499 * of_remove_property - Remove a property from a node.
1501 * Note that we don't actually remove it, since we have given out
1502 * who-knows-how-many pointers to the data using get-property.
1503 * Instead we just move the property to the "dead properties"
1504 * list, so it won't be found any more.
1506 int of_remove_property(struct device_node *np, struct property *prop)
1508 struct property **next;
1509 unsigned long flags;
1513 rc = of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop);
1517 raw_spin_lock_irqsave(&devtree_lock, flags);
1518 next = &np->properties;
1520 if (*next == prop) {
1521 /* found the node */
1523 prop->next = np->deadprops;
1524 np->deadprops = prop;
1528 next = &(*next)->next;
1530 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1535 #ifdef CONFIG_PROC_DEVICETREE
1536 /* try to remove the proc node as well */
1538 proc_device_tree_remove_prop(np->pde, prop);
1539 #endif /* CONFIG_PROC_DEVICETREE */
1545 * of_update_property - Update a property in a node, if the property does
1546 * not exist, add it.
1548 * Note that we don't actually remove it, since we have given out
1549 * who-knows-how-many pointers to the data using get-property.
1550 * Instead we just move the property to the "dead properties" list,
1551 * and add the new property to the property list
1553 int of_update_property(struct device_node *np, struct property *newprop)
1555 struct property **next, *oldprop;
1556 unsigned long flags;
1559 rc = of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop);
1566 oldprop = of_find_property(np, newprop->name, NULL);
1568 return of_add_property(np, newprop);
1570 raw_spin_lock_irqsave(&devtree_lock, flags);
1571 next = &np->properties;
1573 if (*next == oldprop) {
1574 /* found the node */
1575 newprop->next = oldprop->next;
1577 oldprop->next = np->deadprops;
1578 np->deadprops = oldprop;
1582 next = &(*next)->next;
1584 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1589 #ifdef CONFIG_PROC_DEVICETREE
1590 /* try to add to proc as well if it was initialized */
1592 proc_device_tree_update_prop(np->pde, newprop, oldprop);
1593 #endif /* CONFIG_PROC_DEVICETREE */
1598 #if defined(CONFIG_OF_DYNAMIC)
1600 * Support for dynamic device trees.
1602 * On some platforms, the device tree can be manipulated at runtime.
1603 * The routines in this section support adding, removing and changing
1604 * device tree nodes.
1607 static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
1609 int of_reconfig_notifier_register(struct notifier_block *nb)
1611 return blocking_notifier_chain_register(&of_reconfig_chain, nb);
1613 EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
1615 int of_reconfig_notifier_unregister(struct notifier_block *nb)
1617 return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
1619 EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
1621 int of_reconfig_notify(unsigned long action, void *p)
1625 rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
1626 return notifier_to_errno(rc);
1629 #ifdef CONFIG_PROC_DEVICETREE
1630 static void of_add_proc_dt_entry(struct device_node *dn)
1632 struct proc_dir_entry *ent;
1634 ent = proc_mkdir(strrchr(dn->full_name, '/') + 1, dn->parent->pde);
1636 proc_device_tree_add_node(dn, ent);
1639 static void of_add_proc_dt_entry(struct device_node *dn)
1646 * of_attach_node - Plug a device node into the tree and global list.
1648 int of_attach_node(struct device_node *np)
1650 unsigned long flags;
1653 rc = of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, np);
1657 raw_spin_lock_irqsave(&devtree_lock, flags);
1658 np->sibling = np->parent->child;
1659 np->allnext = of_allnodes;
1660 np->parent->child = np;
1662 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1664 of_add_proc_dt_entry(np);
1668 #ifdef CONFIG_PROC_DEVICETREE
1669 static void of_remove_proc_dt_entry(struct device_node *dn)
1671 proc_remove(dn->pde);
1674 static void of_remove_proc_dt_entry(struct device_node *dn)
1681 * of_detach_node - "Unplug" a node from the device tree.
1683 * The caller must hold a reference to the node. The memory associated with
1684 * the node is not freed until its refcount goes to zero.
1686 int of_detach_node(struct device_node *np)
1688 struct device_node *parent;
1689 unsigned long flags;
1692 rc = of_reconfig_notify(OF_RECONFIG_DETACH_NODE, np);
1696 raw_spin_lock_irqsave(&devtree_lock, flags);
1698 if (of_node_check_flag(np, OF_DETACHED)) {
1699 /* someone already detached it */
1700 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1704 parent = np->parent;
1706 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1710 if (of_allnodes == np)
1711 of_allnodes = np->allnext;
1713 struct device_node *prev;
1714 for (prev = of_allnodes;
1715 prev->allnext != np;
1716 prev = prev->allnext)
1718 prev->allnext = np->allnext;
1721 if (parent->child == np)
1722 parent->child = np->sibling;
1724 struct device_node *prevsib;
1725 for (prevsib = np->parent->child;
1726 prevsib->sibling != np;
1727 prevsib = prevsib->sibling)
1729 prevsib->sibling = np->sibling;
1732 of_node_set_flag(np, OF_DETACHED);
1733 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1735 of_remove_proc_dt_entry(np);
1738 #endif /* defined(CONFIG_OF_DYNAMIC) */
1740 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1741 int id, const char *stem, int stem_len)
1745 strncpy(ap->stem, stem, stem_len);
1746 ap->stem[stem_len] = 0;
1747 list_add_tail(&ap->link, &aliases_lookup);
1748 pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
1749 ap->alias, ap->stem, ap->id, of_node_full_name(np));
1753 * of_alias_scan - Scan all properties of 'aliases' node
1755 * The function scans all the properties of 'aliases' node and populate
1756 * the the global lookup table with the properties. It returns the
1757 * number of alias_prop found, or error code in error case.
1759 * @dt_alloc: An allocator that provides a virtual address to memory
1760 * for the resulting tree
1762 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1764 struct property *pp;
1766 of_chosen = of_find_node_by_path("/chosen");
1767 if (of_chosen == NULL)
1768 of_chosen = of_find_node_by_path("/chosen@0");
1773 name = of_get_property(of_chosen, "linux,stdout-path", NULL);
1775 of_stdout = of_find_node_by_path(name);
1778 of_aliases = of_find_node_by_path("/aliases");
1782 for_each_property_of_node(of_aliases, pp) {
1783 const char *start = pp->name;
1784 const char *end = start + strlen(start);
1785 struct device_node *np;
1786 struct alias_prop *ap;
1789 /* Skip those we do not want to proceed */
1790 if (!strcmp(pp->name, "name") ||
1791 !strcmp(pp->name, "phandle") ||
1792 !strcmp(pp->name, "linux,phandle"))
1795 np = of_find_node_by_path(pp->value);
1799 /* walk the alias backwards to extract the id and work out
1800 * the 'stem' string */
1801 while (isdigit(*(end-1)) && end > start)
1805 if (kstrtoint(end, 10, &id) < 0)
1808 /* Allocate an alias_prop with enough space for the stem */
1809 ap = dt_alloc(sizeof(*ap) + len + 1, 4);
1812 memset(ap, 0, sizeof(*ap) + len + 1);
1814 of_alias_add(ap, np, id, start, len);
1819 * of_alias_get_id - Get alias id for the given device_node
1820 * @np: Pointer to the given device_node
1821 * @stem: Alias stem of the given device_node
1823 * The function travels the lookup table to get alias id for the given
1824 * device_node and alias stem. It returns the alias id if find it.
1826 int of_alias_get_id(struct device_node *np, const char *stem)
1828 struct alias_prop *app;
1831 mutex_lock(&of_aliases_mutex);
1832 list_for_each_entry(app, &aliases_lookup, link) {
1833 if (strcmp(app->stem, stem) != 0)
1836 if (np == app->np) {
1841 mutex_unlock(&of_aliases_mutex);
1845 EXPORT_SYMBOL_GPL(of_alias_get_id);
1847 const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
1850 const void *curv = cur;
1860 curv += sizeof(*cur);
1861 if (curv >= prop->value + prop->length)
1865 *pu = be32_to_cpup(curv);
1868 EXPORT_SYMBOL_GPL(of_prop_next_u32);
1870 const char *of_prop_next_string(struct property *prop, const char *cur)
1872 const void *curv = cur;
1880 curv += strlen(cur) + 1;
1881 if (curv >= prop->value + prop->length)
1886 EXPORT_SYMBOL_GPL(of_prop_next_string);
1889 * of_device_is_stdout_path - check if a device node matches the
1890 * linux,stdout-path property
1892 * Check if this device node matches the linux,stdout-path property
1893 * in the chosen node. return true if yes, false otherwise.
1895 int of_device_is_stdout_path(struct device_node *dn)
1900 return of_stdout == dn;
1902 EXPORT_SYMBOL_GPL(of_device_is_stdout_path);