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)
421 status = __of_get_property(device, "status", &statlen);
426 if (!strcmp(status, "okay") || !strcmp(status, "ok"))
434 * of_device_is_available - check if a device is available for use
436 * @device: Node to check for availability
438 * Returns 1 if the status property is absent or set to "okay" or "ok",
441 int of_device_is_available(const struct device_node *device)
446 raw_spin_lock_irqsave(&devtree_lock, flags);
447 res = __of_device_is_available(device);
448 raw_spin_unlock_irqrestore(&devtree_lock, flags);
452 EXPORT_SYMBOL(of_device_is_available);
455 * of_get_parent - Get a node's parent if any
456 * @node: Node to get parent
458 * Returns a node pointer with refcount incremented, use
459 * of_node_put() on it when done.
461 struct device_node *of_get_parent(const struct device_node *node)
463 struct device_node *np;
469 raw_spin_lock_irqsave(&devtree_lock, flags);
470 np = of_node_get(node->parent);
471 raw_spin_unlock_irqrestore(&devtree_lock, flags);
474 EXPORT_SYMBOL(of_get_parent);
477 * of_get_next_parent - Iterate to a node's parent
478 * @node: Node to get parent of
480 * This is like of_get_parent() except that it drops the
481 * refcount on the passed node, making it suitable for iterating
482 * through a node's parents.
484 * Returns a node pointer with refcount incremented, use
485 * of_node_put() on it when done.
487 struct device_node *of_get_next_parent(struct device_node *node)
489 struct device_node *parent;
495 raw_spin_lock_irqsave(&devtree_lock, flags);
496 parent = of_node_get(node->parent);
498 raw_spin_unlock_irqrestore(&devtree_lock, flags);
501 EXPORT_SYMBOL(of_get_next_parent);
504 * of_get_next_child - Iterate a node childs
506 * @prev: previous child of the parent node, or NULL to get first
508 * Returns a node pointer with refcount incremented, use
509 * of_node_put() on it when done.
511 struct device_node *of_get_next_child(const struct device_node *node,
512 struct device_node *prev)
514 struct device_node *next;
517 raw_spin_lock_irqsave(&devtree_lock, flags);
518 next = prev ? prev->sibling : node->child;
519 for (; next; next = next->sibling)
520 if (of_node_get(next))
523 raw_spin_unlock_irqrestore(&devtree_lock, flags);
526 EXPORT_SYMBOL(of_get_next_child);
529 * of_get_next_available_child - Find the next available child node
531 * @prev: previous child of the parent node, or NULL to get first
533 * This function is like of_get_next_child(), except that it
534 * automatically skips any disabled nodes (i.e. status = "disabled").
536 struct device_node *of_get_next_available_child(const struct device_node *node,
537 struct device_node *prev)
539 struct device_node *next;
542 raw_spin_lock_irqsave(&devtree_lock, flags);
543 next = prev ? prev->sibling : node->child;
544 for (; next; next = next->sibling) {
545 if (!__of_device_is_available(next))
547 if (of_node_get(next))
551 raw_spin_unlock_irqrestore(&devtree_lock, flags);
554 EXPORT_SYMBOL(of_get_next_available_child);
557 * of_get_child_by_name - Find the child node by name for a given parent
559 * @name: child name to look for.
561 * This function looks for child node for given matching name
563 * Returns a node pointer if found, with refcount incremented, use
564 * of_node_put() on it when done.
565 * Returns NULL if node is not found.
567 struct device_node *of_get_child_by_name(const struct device_node *node,
570 struct device_node *child;
572 for_each_child_of_node(node, child)
573 if (child->name && (of_node_cmp(child->name, name) == 0))
577 EXPORT_SYMBOL(of_get_child_by_name);
580 * of_find_node_by_path - Find a node matching a full OF path
581 * @path: The full path to match
583 * Returns a node pointer with refcount incremented, use
584 * of_node_put() on it when done.
586 struct device_node *of_find_node_by_path(const char *path)
588 struct device_node *np = of_allnodes;
591 raw_spin_lock_irqsave(&devtree_lock, flags);
592 for (; np; np = np->allnext) {
593 if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
597 raw_spin_unlock_irqrestore(&devtree_lock, flags);
600 EXPORT_SYMBOL(of_find_node_by_path);
603 * of_find_node_by_name - Find a node by its "name" property
604 * @from: The node to start searching from or NULL, the node
605 * you pass will not be searched, only the next one
606 * will; typically, you pass what the previous call
607 * returned. of_node_put() will be called on it
608 * @name: The name string to match against
610 * Returns a node pointer with refcount incremented, use
611 * of_node_put() on it when done.
613 struct device_node *of_find_node_by_name(struct device_node *from,
616 struct device_node *np;
619 raw_spin_lock_irqsave(&devtree_lock, flags);
620 np = from ? from->allnext : of_allnodes;
621 for (; np; np = np->allnext)
622 if (np->name && (of_node_cmp(np->name, name) == 0)
626 raw_spin_unlock_irqrestore(&devtree_lock, flags);
629 EXPORT_SYMBOL(of_find_node_by_name);
632 * of_find_node_by_type - Find a node by its "device_type" property
633 * @from: The node to start searching from, or NULL to start searching
634 * the entire device tree. The node you pass will not be
635 * searched, only the next one will; typically, you pass
636 * what the previous call returned. of_node_put() will be
637 * called on from for you.
638 * @type: The type string to match against
640 * Returns a node pointer with refcount incremented, use
641 * of_node_put() on it when done.
643 struct device_node *of_find_node_by_type(struct device_node *from,
646 struct device_node *np;
649 raw_spin_lock_irqsave(&devtree_lock, flags);
650 np = from ? from->allnext : of_allnodes;
651 for (; np; np = np->allnext)
652 if (np->type && (of_node_cmp(np->type, type) == 0)
656 raw_spin_unlock_irqrestore(&devtree_lock, flags);
659 EXPORT_SYMBOL(of_find_node_by_type);
662 * of_find_compatible_node - Find a node based on type and one of the
663 * tokens in its "compatible" property
664 * @from: The node to start searching from or NULL, the node
665 * you pass will not be searched, only the next one
666 * will; typically, you pass what the previous call
667 * returned. of_node_put() will be called on it
668 * @type: The type string to match "device_type" or NULL to ignore
669 * @compatible: The string to match to one of the tokens in the device
672 * Returns a node pointer with refcount incremented, use
673 * of_node_put() on it when done.
675 struct device_node *of_find_compatible_node(struct device_node *from,
676 const char *type, const char *compatible)
678 struct device_node *np;
681 raw_spin_lock_irqsave(&devtree_lock, flags);
682 np = from ? from->allnext : of_allnodes;
683 for (; np; np = np->allnext) {
685 && !(np->type && (of_node_cmp(np->type, type) == 0)))
687 if (__of_device_is_compatible(np, compatible) &&
692 raw_spin_unlock_irqrestore(&devtree_lock, flags);
695 EXPORT_SYMBOL(of_find_compatible_node);
698 * of_find_node_with_property - Find a node which has a property with
700 * @from: The node to start searching from or NULL, the node
701 * you pass will not be searched, only the next one
702 * will; typically, you pass what the previous call
703 * returned. of_node_put() will be called on it
704 * @prop_name: The name of the property to look for.
706 * Returns a node pointer with refcount incremented, use
707 * of_node_put() on it when done.
709 struct device_node *of_find_node_with_property(struct device_node *from,
710 const char *prop_name)
712 struct device_node *np;
716 raw_spin_lock_irqsave(&devtree_lock, flags);
717 np = from ? from->allnext : of_allnodes;
718 for (; np; np = np->allnext) {
719 for (pp = np->properties; pp; pp = pp->next) {
720 if (of_prop_cmp(pp->name, prop_name) == 0) {
728 raw_spin_unlock_irqrestore(&devtree_lock, flags);
731 EXPORT_SYMBOL(of_find_node_with_property);
734 const struct of_device_id *__of_match_node(const struct of_device_id *matches,
735 const struct device_node *node)
740 while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
742 if (matches->name[0])
744 && !strcmp(matches->name, node->name);
745 if (matches->type[0])
747 && !strcmp(matches->type, node->type);
748 if (matches->compatible[0])
749 match &= __of_device_is_compatible(node,
750 matches->compatible);
759 * of_match_node - Tell if an device_node has a matching of_match structure
760 * @matches: array of of device match structures to search in
761 * @node: the of device structure to match against
763 * Low level utility function used by device matching.
765 const struct of_device_id *of_match_node(const struct of_device_id *matches,
766 const struct device_node *node)
768 const struct of_device_id *match;
771 raw_spin_lock_irqsave(&devtree_lock, flags);
772 match = __of_match_node(matches, node);
773 raw_spin_unlock_irqrestore(&devtree_lock, flags);
776 EXPORT_SYMBOL(of_match_node);
779 * of_find_matching_node_and_match - Find a node based on an of_device_id
781 * @from: The node to start searching from or NULL, the node
782 * you pass will not be searched, only the next one
783 * will; typically, you pass what the previous call
784 * returned. of_node_put() will be called on it
785 * @matches: array of of device match structures to search in
786 * @match Updated to point at the matches entry which matched
788 * Returns a node pointer with refcount incremented, use
789 * of_node_put() on it when done.
791 struct device_node *of_find_matching_node_and_match(struct device_node *from,
792 const struct of_device_id *matches,
793 const struct of_device_id **match)
795 struct device_node *np;
796 const struct of_device_id *m;
802 raw_spin_lock_irqsave(&devtree_lock, flags);
803 np = from ? from->allnext : of_allnodes;
804 for (; np; np = np->allnext) {
805 m = __of_match_node(matches, np);
806 if (m && of_node_get(np)) {
813 raw_spin_unlock_irqrestore(&devtree_lock, flags);
816 EXPORT_SYMBOL(of_find_matching_node_and_match);
819 * of_modalias_node - Lookup appropriate modalias for a device node
820 * @node: pointer to a device tree node
821 * @modalias: Pointer to buffer that modalias value will be copied into
822 * @len: Length of modalias value
824 * Based on the value of the compatible property, this routine will attempt
825 * to choose an appropriate modalias value for a particular device tree node.
826 * It does this by stripping the manufacturer prefix (as delimited by a ',')
827 * from the first entry in the compatible list property.
829 * This routine returns 0 on success, <0 on failure.
831 int of_modalias_node(struct device_node *node, char *modalias, int len)
833 const char *compatible, *p;
836 compatible = of_get_property(node, "compatible", &cplen);
837 if (!compatible || strlen(compatible) > cplen)
839 p = strchr(compatible, ',');
840 strlcpy(modalias, p ? p + 1 : compatible, len);
843 EXPORT_SYMBOL_GPL(of_modalias_node);
846 * of_find_node_by_phandle - Find a node given a phandle
847 * @handle: phandle of the node to find
849 * Returns a node pointer with refcount incremented, use
850 * of_node_put() on it when done.
852 struct device_node *of_find_node_by_phandle(phandle handle)
854 struct device_node *np;
857 raw_spin_lock_irqsave(&devtree_lock, flags);
858 for (np = of_allnodes; np; np = np->allnext)
859 if (np->phandle == handle)
862 raw_spin_unlock_irqrestore(&devtree_lock, flags);
865 EXPORT_SYMBOL(of_find_node_by_phandle);
868 * of_find_property_value_of_size
870 * @np: device node from which the property value is to be read.
871 * @propname: name of the property to be searched.
872 * @len: requested length of property value
874 * Search for a property in a device node and valid the requested size.
875 * Returns the property value on success, -EINVAL if the property does not
876 * exist, -ENODATA if property does not have a value, and -EOVERFLOW if the
877 * property data isn't large enough.
880 static void *of_find_property_value_of_size(const struct device_node *np,
881 const char *propname, u32 len)
883 struct property *prop = of_find_property(np, propname, NULL);
886 return ERR_PTR(-EINVAL);
888 return ERR_PTR(-ENODATA);
889 if (len > prop->length)
890 return ERR_PTR(-EOVERFLOW);
896 * of_property_read_u32_index - Find and read a u32 from a multi-value property.
898 * @np: device node from which the property value is to be read.
899 * @propname: name of the property to be searched.
900 * @index: index of the u32 in the list of values
901 * @out_value: pointer to return value, modified only if no error.
903 * Search for a property in a device node and read nth 32-bit value from
904 * it. Returns 0 on success, -EINVAL if the property does not exist,
905 * -ENODATA if property does not have a value, and -EOVERFLOW if the
906 * property data isn't large enough.
908 * The out_value is modified only if a valid u32 value can be decoded.
910 int of_property_read_u32_index(const struct device_node *np,
911 const char *propname,
912 u32 index, u32 *out_value)
914 const u32 *val = of_find_property_value_of_size(np, propname,
915 ((index + 1) * sizeof(*out_value)));
920 *out_value = be32_to_cpup(((__be32 *)val) + index);
923 EXPORT_SYMBOL_GPL(of_property_read_u32_index);
926 * of_property_read_u8_array - Find and read an array of u8 from a property.
928 * @np: device node from which the property value is to be read.
929 * @propname: name of the property to be searched.
930 * @out_values: pointer to return value, modified only if return value is 0.
931 * @sz: number of array elements to read
933 * Search for a property in a device node and read 8-bit value(s) from
934 * it. Returns 0 on success, -EINVAL if the property does not exist,
935 * -ENODATA if property does not have a value, and -EOVERFLOW if the
936 * property data isn't large enough.
938 * dts entry of array should be like:
939 * property = /bits/ 8 <0x50 0x60 0x70>;
941 * The out_values is modified only if a valid u8 value can be decoded.
943 int of_property_read_u8_array(const struct device_node *np,
944 const char *propname, u8 *out_values, size_t sz)
946 const u8 *val = of_find_property_value_of_size(np, propname,
947 (sz * sizeof(*out_values)));
953 *out_values++ = *val++;
956 EXPORT_SYMBOL_GPL(of_property_read_u8_array);
959 * of_property_read_u16_array - Find and read an array of u16 from a property.
961 * @np: device node from which the property value is to be read.
962 * @propname: name of the property to be searched.
963 * @out_values: pointer to return value, modified only if return value is 0.
964 * @sz: number of array elements to read
966 * Search for a property in a device node and read 16-bit value(s) from
967 * it. Returns 0 on success, -EINVAL if the property does not exist,
968 * -ENODATA if property does not have a value, and -EOVERFLOW if the
969 * property data isn't large enough.
971 * dts entry of array should be like:
972 * property = /bits/ 16 <0x5000 0x6000 0x7000>;
974 * The out_values is modified only if a valid u16 value can be decoded.
976 int of_property_read_u16_array(const struct device_node *np,
977 const char *propname, u16 *out_values, size_t sz)
979 const __be16 *val = of_find_property_value_of_size(np, propname,
980 (sz * sizeof(*out_values)));
986 *out_values++ = be16_to_cpup(val++);
989 EXPORT_SYMBOL_GPL(of_property_read_u16_array);
992 * of_property_read_u32_array - Find and read an array of 32 bit integers
995 * @np: device node from which the property value is to be read.
996 * @propname: name of the property to be searched.
997 * @out_values: pointer to return value, modified only if return value is 0.
998 * @sz: number of array elements to read
1000 * Search for a property in a device node and read 32-bit value(s) from
1001 * it. Returns 0 on success, -EINVAL if the property does not exist,
1002 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1003 * property data isn't large enough.
1005 * The out_values is modified only if a valid u32 value can be decoded.
1007 int of_property_read_u32_array(const struct device_node *np,
1008 const char *propname, u32 *out_values,
1011 const __be32 *val = of_find_property_value_of_size(np, propname,
1012 (sz * sizeof(*out_values)));
1015 return PTR_ERR(val);
1018 *out_values++ = be32_to_cpup(val++);
1021 EXPORT_SYMBOL_GPL(of_property_read_u32_array);
1024 * of_property_read_u64 - Find and read a 64 bit integer from a property
1025 * @np: device node from which the property value is to be read.
1026 * @propname: name of the property to be searched.
1027 * @out_value: pointer to return value, modified only if return value is 0.
1029 * Search for a property in a device node and read a 64-bit value from
1030 * it. Returns 0 on success, -EINVAL if the property does not exist,
1031 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1032 * property data isn't large enough.
1034 * The out_value is modified only if a valid u64 value can be decoded.
1036 int of_property_read_u64(const struct device_node *np, const char *propname,
1039 const __be32 *val = of_find_property_value_of_size(np, propname,
1040 sizeof(*out_value));
1043 return PTR_ERR(val);
1045 *out_value = of_read_number(val, 2);
1048 EXPORT_SYMBOL_GPL(of_property_read_u64);
1051 * of_property_read_string - Find and read a string from a property
1052 * @np: device node from which the property value is to be read.
1053 * @propname: name of the property to be searched.
1054 * @out_string: pointer to null terminated return string, modified only if
1055 * return value is 0.
1057 * Search for a property in a device tree node and retrieve a null
1058 * terminated string value (pointer to data, not a copy). Returns 0 on
1059 * success, -EINVAL if the property does not exist, -ENODATA if property
1060 * does not have a value, and -EILSEQ if the string is not null-terminated
1061 * within the length of the property data.
1063 * The out_string pointer is modified only if a valid string can be decoded.
1065 int of_property_read_string(struct device_node *np, const char *propname,
1066 const char **out_string)
1068 struct property *prop = of_find_property(np, propname, NULL);
1073 if (strnlen(prop->value, prop->length) >= prop->length)
1075 *out_string = prop->value;
1078 EXPORT_SYMBOL_GPL(of_property_read_string);
1081 * of_property_read_string_index - Find and read a string from a multiple
1083 * @np: device node from which the property value is to be read.
1084 * @propname: name of the property to be searched.
1085 * @index: index of the string in the list of strings
1086 * @out_string: pointer to null terminated return string, modified only if
1087 * return value is 0.
1089 * Search for a property in a device tree node and retrieve a null
1090 * terminated string value (pointer to data, not a copy) in the list of strings
1091 * contained in that property.
1092 * Returns 0 on success, -EINVAL if the property does not exist, -ENODATA if
1093 * property does not have a value, and -EILSEQ if the string is not
1094 * null-terminated within the length of the property data.
1096 * The out_string pointer is modified only if a valid string can be decoded.
1098 int of_property_read_string_index(struct device_node *np, const char *propname,
1099 int index, const char **output)
1101 struct property *prop = of_find_property(np, propname, NULL);
1103 size_t l = 0, total = 0;
1110 if (strnlen(prop->value, prop->length) >= prop->length)
1115 for (i = 0; total < prop->length; total += l, p += l) {
1124 EXPORT_SYMBOL_GPL(of_property_read_string_index);
1127 * of_property_match_string() - Find string in a list and return index
1128 * @np: pointer to node containing string list property
1129 * @propname: string list property name
1130 * @string: pointer to string to search for in string list
1132 * This function searches a string list property and returns the index
1133 * of a specific string value.
1135 int of_property_match_string(struct device_node *np, const char *propname,
1138 struct property *prop = of_find_property(np, propname, NULL);
1141 const char *p, *end;
1149 end = p + prop->length;
1151 for (i = 0; p < end; i++, p += l) {
1155 pr_debug("comparing %s with %s\n", string, p);
1156 if (strcmp(string, p) == 0)
1157 return i; /* Found it; return index */
1161 EXPORT_SYMBOL_GPL(of_property_match_string);
1164 * of_property_count_strings - Find and return the number of strings from a
1165 * multiple strings property.
1166 * @np: device node from which the property value is to be read.
1167 * @propname: name of the property to be searched.
1169 * Search for a property in a device tree node and retrieve the number of null
1170 * terminated string contain in it. Returns the number of strings on
1171 * success, -EINVAL if the property does not exist, -ENODATA if property
1172 * does not have a value, and -EILSEQ if the string is not null-terminated
1173 * within the length of the property data.
1175 int of_property_count_strings(struct device_node *np, const char *propname)
1177 struct property *prop = of_find_property(np, propname, NULL);
1179 size_t l = 0, total = 0;
1186 if (strnlen(prop->value, prop->length) >= prop->length)
1191 for (i = 0; total < prop->length; total += l, p += l, i++)
1196 EXPORT_SYMBOL_GPL(of_property_count_strings);
1198 void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
1201 printk("%s %s", msg, of_node_full_name(args->np));
1202 for (i = 0; i < args->args_count; i++)
1203 printk(i ? ",%08x" : ":%08x", args->args[i]);
1207 static int __of_parse_phandle_with_args(const struct device_node *np,
1208 const char *list_name,
1209 const char *cells_name,
1210 int cell_count, int index,
1211 struct of_phandle_args *out_args)
1213 const __be32 *list, *list_end;
1214 int rc = 0, size, cur_index = 0;
1216 struct device_node *node = NULL;
1219 /* Retrieve the phandle list property */
1220 list = of_get_property(np, list_name, &size);
1223 list_end = list + size / sizeof(*list);
1225 /* Loop over the phandles until all the requested entry is found */
1226 while (list < list_end) {
1231 * If phandle is 0, then it is an empty entry with no
1232 * arguments. Skip forward to the next entry.
1234 phandle = be32_to_cpup(list++);
1237 * Find the provider node and parse the #*-cells
1238 * property to determine the argument length.
1240 * This is not needed if the cell count is hard-coded
1241 * (i.e. cells_name not set, but cell_count is set),
1242 * except when we're going to return the found node
1245 if (cells_name || cur_index == index) {
1246 node = of_find_node_by_phandle(phandle);
1248 pr_err("%s: could not find phandle\n",
1255 if (of_property_read_u32(node, cells_name,
1257 pr_err("%s: could not get %s for %s\n",
1258 np->full_name, cells_name,
1267 * Make sure that the arguments actually fit in the
1268 * remaining property data length
1270 if (list + count > list_end) {
1271 pr_err("%s: arguments longer than property\n",
1278 * All of the error cases above bail out of the loop, so at
1279 * this point, the parsing is successful. If the requested
1280 * index matches, then fill the out_args structure and return,
1281 * or return -ENOENT for an empty entry.
1284 if (cur_index == index) {
1290 if (WARN_ON(count > MAX_PHANDLE_ARGS))
1291 count = MAX_PHANDLE_ARGS;
1292 out_args->np = node;
1293 out_args->args_count = count;
1294 for (i = 0; i < count; i++)
1295 out_args->args[i] = be32_to_cpup(list++);
1300 /* Found it! return success */
1311 * Unlock node before returning result; will be one of:
1312 * -ENOENT : index is for empty phandle
1313 * -EINVAL : parsing error on data
1314 * [1..n] : Number of phandle (count mode; when index = -1)
1316 rc = index < 0 ? cur_index : -ENOENT;
1324 * of_parse_phandle - Resolve a phandle property to a device_node pointer
1325 * @np: Pointer to device node holding phandle property
1326 * @phandle_name: Name of property holding a phandle value
1327 * @index: For properties holding a table of phandles, this is the index into
1330 * Returns the device_node pointer with refcount incremented. Use
1331 * of_node_put() on it when done.
1333 struct device_node *of_parse_phandle(const struct device_node *np,
1334 const char *phandle_name, int index)
1336 struct of_phandle_args args;
1341 if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0,
1347 EXPORT_SYMBOL(of_parse_phandle);
1350 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
1351 * @np: pointer to a device tree node containing a list
1352 * @list_name: property name that contains a list
1353 * @cells_name: property name that specifies phandles' arguments count
1354 * @index: index of a phandle to parse out
1355 * @out_args: optional pointer to output arguments structure (will be filled)
1357 * This function is useful to parse lists of phandles and their arguments.
1358 * Returns 0 on success and fills out_args, on error returns appropriate
1361 * Caller is responsible to call of_node_put() on the returned out_args->node
1367 * #list-cells = <2>;
1371 * #list-cells = <1>;
1375 * list = <&phandle1 1 2 &phandle2 3>;
1378 * To get a device_node of the `node2' node you may call this:
1379 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
1381 int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
1382 const char *cells_name, int index,
1383 struct of_phandle_args *out_args)
1387 return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
1390 EXPORT_SYMBOL(of_parse_phandle_with_args);
1393 * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
1394 * @np: pointer to a device tree node containing a list
1395 * @list_name: property name that contains a list
1396 * @cell_count: number of argument cells following the phandle
1397 * @index: index of a phandle to parse out
1398 * @out_args: optional pointer to output arguments structure (will be filled)
1400 * This function is useful to parse lists of phandles and their arguments.
1401 * Returns 0 on success and fills out_args, on error returns appropriate
1404 * Caller is responsible to call of_node_put() on the returned out_args->node
1416 * list = <&phandle1 0 2 &phandle2 2 3>;
1419 * To get a device_node of the `node2' node you may call this:
1420 * of_parse_phandle_with_fixed_args(node3, "list", 2, 1, &args);
1422 int of_parse_phandle_with_fixed_args(const struct device_node *np,
1423 const char *list_name, int cell_count,
1424 int index, struct of_phandle_args *out_args)
1428 return __of_parse_phandle_with_args(np, list_name, NULL, cell_count,
1431 EXPORT_SYMBOL(of_parse_phandle_with_fixed_args);
1434 * of_count_phandle_with_args() - Find the number of phandles references in a property
1435 * @np: pointer to a device tree node containing a list
1436 * @list_name: property name that contains a list
1437 * @cells_name: property name that specifies phandles' arguments count
1439 * Returns the number of phandle + argument tuples within a property. It
1440 * is a typical pattern to encode a list of phandle and variable
1441 * arguments into a single property. The number of arguments is encoded
1442 * by a property in the phandle-target node. For example, a gpios
1443 * property would contain a list of GPIO specifies consisting of a
1444 * phandle and 1 or more arguments. The number of arguments are
1445 * determined by the #gpio-cells property in the node pointed to by the
1448 int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
1449 const char *cells_name)
1451 return __of_parse_phandle_with_args(np, list_name, cells_name, 0, -1,
1454 EXPORT_SYMBOL(of_count_phandle_with_args);
1456 #if defined(CONFIG_OF_DYNAMIC)
1457 static int of_property_notify(int action, struct device_node *np,
1458 struct property *prop)
1460 struct of_prop_reconfig pr;
1464 return of_reconfig_notify(action, &pr);
1467 static int of_property_notify(int action, struct device_node *np,
1468 struct property *prop)
1475 * of_add_property - Add a property to a node
1477 int of_add_property(struct device_node *np, struct property *prop)
1479 struct property **next;
1480 unsigned long flags;
1483 rc = of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop);
1488 raw_spin_lock_irqsave(&devtree_lock, flags);
1489 next = &np->properties;
1491 if (strcmp(prop->name, (*next)->name) == 0) {
1492 /* duplicate ! don't insert it */
1493 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1496 next = &(*next)->next;
1499 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1501 #ifdef CONFIG_PROC_DEVICETREE
1502 /* try to add to proc as well if it was initialized */
1504 proc_device_tree_add_prop(np->pde, prop);
1505 #endif /* CONFIG_PROC_DEVICETREE */
1511 * of_remove_property - Remove a property from a node.
1513 * Note that we don't actually remove it, since we have given out
1514 * who-knows-how-many pointers to the data using get-property.
1515 * Instead we just move the property to the "dead properties"
1516 * list, so it won't be found any more.
1518 int of_remove_property(struct device_node *np, struct property *prop)
1520 struct property **next;
1521 unsigned long flags;
1525 rc = of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop);
1529 raw_spin_lock_irqsave(&devtree_lock, flags);
1530 next = &np->properties;
1532 if (*next == prop) {
1533 /* found the node */
1535 prop->next = np->deadprops;
1536 np->deadprops = prop;
1540 next = &(*next)->next;
1542 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1547 #ifdef CONFIG_PROC_DEVICETREE
1548 /* try to remove the proc node as well */
1550 proc_device_tree_remove_prop(np->pde, prop);
1551 #endif /* CONFIG_PROC_DEVICETREE */
1557 * of_update_property - Update a property in a node, if the property does
1558 * not exist, add it.
1560 * Note that we don't actually remove it, since we have given out
1561 * who-knows-how-many pointers to the data using get-property.
1562 * Instead we just move the property to the "dead properties" list,
1563 * and add the new property to the property list
1565 int of_update_property(struct device_node *np, struct property *newprop)
1567 struct property **next, *oldprop;
1568 unsigned long flags;
1571 rc = of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop);
1578 oldprop = of_find_property(np, newprop->name, NULL);
1580 return of_add_property(np, newprop);
1582 raw_spin_lock_irqsave(&devtree_lock, flags);
1583 next = &np->properties;
1585 if (*next == oldprop) {
1586 /* found the node */
1587 newprop->next = oldprop->next;
1589 oldprop->next = np->deadprops;
1590 np->deadprops = oldprop;
1594 next = &(*next)->next;
1596 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1601 #ifdef CONFIG_PROC_DEVICETREE
1602 /* try to add to proc as well if it was initialized */
1604 proc_device_tree_update_prop(np->pde, newprop, oldprop);
1605 #endif /* CONFIG_PROC_DEVICETREE */
1610 #if defined(CONFIG_OF_DYNAMIC)
1612 * Support for dynamic device trees.
1614 * On some platforms, the device tree can be manipulated at runtime.
1615 * The routines in this section support adding, removing and changing
1616 * device tree nodes.
1619 static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
1621 int of_reconfig_notifier_register(struct notifier_block *nb)
1623 return blocking_notifier_chain_register(&of_reconfig_chain, nb);
1625 EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
1627 int of_reconfig_notifier_unregister(struct notifier_block *nb)
1629 return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
1631 EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
1633 int of_reconfig_notify(unsigned long action, void *p)
1637 rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
1638 return notifier_to_errno(rc);
1641 #ifdef CONFIG_PROC_DEVICETREE
1642 static void of_add_proc_dt_entry(struct device_node *dn)
1644 struct proc_dir_entry *ent;
1646 ent = proc_mkdir(strrchr(dn->full_name, '/') + 1, dn->parent->pde);
1648 proc_device_tree_add_node(dn, ent);
1651 static void of_add_proc_dt_entry(struct device_node *dn)
1658 * of_attach_node - Plug a device node into the tree and global list.
1660 int of_attach_node(struct device_node *np)
1662 unsigned long flags;
1665 rc = of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, np);
1669 raw_spin_lock_irqsave(&devtree_lock, flags);
1670 np->sibling = np->parent->child;
1671 np->allnext = of_allnodes;
1672 np->parent->child = np;
1674 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1676 of_add_proc_dt_entry(np);
1680 #ifdef CONFIG_PROC_DEVICETREE
1681 static void of_remove_proc_dt_entry(struct device_node *dn)
1683 proc_remove(dn->pde);
1686 static void of_remove_proc_dt_entry(struct device_node *dn)
1693 * of_detach_node - "Unplug" a node from the device tree.
1695 * The caller must hold a reference to the node. The memory associated with
1696 * the node is not freed until its refcount goes to zero.
1698 int of_detach_node(struct device_node *np)
1700 struct device_node *parent;
1701 unsigned long flags;
1704 rc = of_reconfig_notify(OF_RECONFIG_DETACH_NODE, np);
1708 raw_spin_lock_irqsave(&devtree_lock, flags);
1710 if (of_node_check_flag(np, OF_DETACHED)) {
1711 /* someone already detached it */
1712 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1716 parent = np->parent;
1718 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1722 if (of_allnodes == np)
1723 of_allnodes = np->allnext;
1725 struct device_node *prev;
1726 for (prev = of_allnodes;
1727 prev->allnext != np;
1728 prev = prev->allnext)
1730 prev->allnext = np->allnext;
1733 if (parent->child == np)
1734 parent->child = np->sibling;
1736 struct device_node *prevsib;
1737 for (prevsib = np->parent->child;
1738 prevsib->sibling != np;
1739 prevsib = prevsib->sibling)
1741 prevsib->sibling = np->sibling;
1744 of_node_set_flag(np, OF_DETACHED);
1745 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1747 of_remove_proc_dt_entry(np);
1750 #endif /* defined(CONFIG_OF_DYNAMIC) */
1752 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1753 int id, const char *stem, int stem_len)
1757 strncpy(ap->stem, stem, stem_len);
1758 ap->stem[stem_len] = 0;
1759 list_add_tail(&ap->link, &aliases_lookup);
1760 pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
1761 ap->alias, ap->stem, ap->id, of_node_full_name(np));
1765 * of_alias_scan - Scan all properties of 'aliases' node
1767 * The function scans all the properties of 'aliases' node and populate
1768 * the the global lookup table with the properties. It returns the
1769 * number of alias_prop found, or error code in error case.
1771 * @dt_alloc: An allocator that provides a virtual address to memory
1772 * for the resulting tree
1774 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1776 struct property *pp;
1778 of_chosen = of_find_node_by_path("/chosen");
1779 if (of_chosen == NULL)
1780 of_chosen = of_find_node_by_path("/chosen@0");
1785 name = of_get_property(of_chosen, "linux,stdout-path", NULL);
1787 of_stdout = of_find_node_by_path(name);
1790 of_aliases = of_find_node_by_path("/aliases");
1794 for_each_property_of_node(of_aliases, pp) {
1795 const char *start = pp->name;
1796 const char *end = start + strlen(start);
1797 struct device_node *np;
1798 struct alias_prop *ap;
1801 /* Skip those we do not want to proceed */
1802 if (!strcmp(pp->name, "name") ||
1803 !strcmp(pp->name, "phandle") ||
1804 !strcmp(pp->name, "linux,phandle"))
1807 np = of_find_node_by_path(pp->value);
1811 /* walk the alias backwards to extract the id and work out
1812 * the 'stem' string */
1813 while (isdigit(*(end-1)) && end > start)
1817 if (kstrtoint(end, 10, &id) < 0)
1820 /* Allocate an alias_prop with enough space for the stem */
1821 ap = dt_alloc(sizeof(*ap) + len + 1, 4);
1824 memset(ap, 0, sizeof(*ap) + len + 1);
1826 of_alias_add(ap, np, id, start, len);
1831 * of_alias_get_id - Get alias id for the given device_node
1832 * @np: Pointer to the given device_node
1833 * @stem: Alias stem of the given device_node
1835 * The function travels the lookup table to get alias id for the given
1836 * device_node and alias stem. It returns the alias id if find it.
1838 int of_alias_get_id(struct device_node *np, const char *stem)
1840 struct alias_prop *app;
1843 mutex_lock(&of_aliases_mutex);
1844 list_for_each_entry(app, &aliases_lookup, link) {
1845 if (strcmp(app->stem, stem) != 0)
1848 if (np == app->np) {
1853 mutex_unlock(&of_aliases_mutex);
1857 EXPORT_SYMBOL_GPL(of_alias_get_id);
1859 const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
1862 const void *curv = cur;
1872 curv += sizeof(*cur);
1873 if (curv >= prop->value + prop->length)
1877 *pu = be32_to_cpup(curv);
1880 EXPORT_SYMBOL_GPL(of_prop_next_u32);
1882 const char *of_prop_next_string(struct property *prop, const char *cur)
1884 const void *curv = cur;
1892 curv += strlen(cur) + 1;
1893 if (curv >= prop->value + prop->length)
1898 EXPORT_SYMBOL_GPL(of_prop_next_string);
1901 * of_device_is_stdout_path - check if a device node matches the
1902 * linux,stdout-path property
1904 * Check if this device node matches the linux,stdout-path property
1905 * in the chosen node. return true if yes, false otherwise.
1907 int of_device_is_stdout_path(struct device_node *dn)
1912 return of_stdout == dn;
1914 EXPORT_SYMBOL_GPL(of_device_is_stdout_path);
1917 * of_find_next_cache_node - Find a node's subsidiary cache
1918 * @np: node of type "cpu" or "cache"
1920 * Returns a node pointer with refcount incremented, use
1921 * of_node_put() on it when done. Caller should hold a reference
1924 struct device_node *of_find_next_cache_node(const struct device_node *np)
1926 struct device_node *child;
1927 const phandle *handle;
1929 handle = of_get_property(np, "l2-cache", NULL);
1931 handle = of_get_property(np, "next-level-cache", NULL);
1934 return of_find_node_by_phandle(be32_to_cpup(handle));
1936 /* OF on pmac has nodes instead of properties named "l2-cache"
1937 * beneath CPU nodes.
1939 if (!strcmp(np->type, "cpu"))
1940 for_each_child_of_node(np, child)
1941 if (!strcmp(child->type, "cache"))