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);
77 #if defined(CONFIG_OF_DYNAMIC)
79 * of_node_get - Increment refcount of a node
80 * @node: Node to inc refcount, NULL is supported to
81 * simplify writing of callers
85 struct device_node *of_node_get(struct device_node *node)
88 kref_get(&node->kref);
91 EXPORT_SYMBOL(of_node_get);
93 static inline struct device_node *kref_to_device_node(struct kref *kref)
95 return container_of(kref, struct device_node, kref);
99 * of_node_release - release a dynamically allocated node
100 * @kref: kref element of the node to be released
102 * In of_node_put() this function is passed to kref_put()
105 static void of_node_release(struct kref *kref)
107 struct device_node *node = kref_to_device_node(kref);
108 struct property *prop = node->properties;
110 /* We should never be releasing nodes that haven't been detached. */
111 if (!of_node_check_flag(node, OF_DETACHED)) {
112 pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name);
114 kref_init(&node->kref);
118 if (!of_node_check_flag(node, OF_DYNAMIC))
122 struct property *next = prop->next;
129 prop = node->deadprops;
130 node->deadprops = NULL;
133 kfree(node->full_name);
139 * of_node_put - Decrement refcount of a node
140 * @node: Node to dec refcount, NULL is supported to
141 * simplify writing of callers
144 void of_node_put(struct device_node *node)
147 kref_put(&node->kref, of_node_release);
149 EXPORT_SYMBOL(of_node_put);
150 #endif /* CONFIG_OF_DYNAMIC */
152 static struct property *__of_find_property(const struct device_node *np,
153 const char *name, int *lenp)
160 for (pp = np->properties; pp; pp = pp->next) {
161 if (of_prop_cmp(pp->name, name) == 0) {
171 struct property *of_find_property(const struct device_node *np,
178 raw_spin_lock_irqsave(&devtree_lock, flags);
179 pp = __of_find_property(np, name, lenp);
180 raw_spin_unlock_irqrestore(&devtree_lock, flags);
184 EXPORT_SYMBOL(of_find_property);
187 * of_find_all_nodes - Get next node in global list
188 * @prev: Previous node or NULL to start iteration
189 * of_node_put() will be called on it
191 * Returns a node pointer with refcount incremented, use
192 * of_node_put() on it when done.
194 struct device_node *of_find_all_nodes(struct device_node *prev)
196 struct device_node *np;
199 raw_spin_lock_irqsave(&devtree_lock, flags);
200 np = prev ? prev->allnext : of_allnodes;
201 for (; np != NULL; np = np->allnext)
205 raw_spin_unlock_irqrestore(&devtree_lock, flags);
208 EXPORT_SYMBOL(of_find_all_nodes);
211 * Find a property with a given name for a given node
212 * and return the value.
214 static const void *__of_get_property(const struct device_node *np,
215 const char *name, int *lenp)
217 struct property *pp = __of_find_property(np, name, lenp);
219 return pp ? pp->value : NULL;
223 * Find a property with a given name for a given node
224 * and return the value.
226 const void *of_get_property(const struct device_node *np, const char *name,
229 struct property *pp = of_find_property(np, name, lenp);
231 return pp ? pp->value : NULL;
233 EXPORT_SYMBOL(of_get_property);
236 * arch_match_cpu_phys_id - Match the given logical CPU and physical id
238 * @cpu: logical cpu index of a core/thread
239 * @phys_id: physical identifier of a core/thread
241 * CPU logical to physical index mapping is architecture specific.
242 * However this __weak function provides a default match of physical
243 * id to logical cpu index. phys_id provided here is usually values read
244 * from the device tree which must match the hardware internal registers.
246 * Returns true if the physical identifier and the logical cpu index
247 * correspond to the same core/thread, false otherwise.
249 bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id)
251 return (u32)phys_id == cpu;
255 * Checks if the given "prop_name" property holds the physical id of the
256 * core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not
257 * NULL, local thread number within the core is returned in it.
259 static bool __of_find_n_match_cpu_property(struct device_node *cpun,
260 const char *prop_name, int cpu, unsigned int *thread)
263 int ac, prop_len, tid;
266 ac = of_n_addr_cells(cpun);
267 cell = of_get_property(cpun, prop_name, &prop_len);
270 prop_len /= sizeof(*cell);
271 for (tid = 0; tid < prop_len; tid++) {
272 hwid = of_read_number(cell, ac);
273 if (arch_match_cpu_phys_id(cpu, hwid)) {
284 * of_get_cpu_node - Get device node associated with the given logical CPU
286 * @cpu: CPU number(logical index) for which device node is required
287 * @thread: if not NULL, local thread number within the physical core is
290 * The main purpose of this function is to retrieve the device node for the
291 * given logical CPU index. It should be used to initialize the of_node in
292 * cpu device. Once of_node in cpu device is populated, all the further
293 * references can use that instead.
295 * CPU logical to physical index mapping is architecture specific and is built
296 * before booting secondary cores. This function uses arch_match_cpu_phys_id
297 * which can be overridden by architecture specific implementation.
299 * Returns a node pointer for the logical cpu if found, else NULL.
301 struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
303 struct device_node *cpun, *cpus;
305 cpus = of_find_node_by_path("/cpus");
307 pr_warn("Missing cpus node, bailing out\n");
311 for_each_child_of_node(cpus, cpun) {
312 if (of_node_cmp(cpun->type, "cpu"))
314 /* Check for non-standard "ibm,ppc-interrupt-server#s" property
315 * for thread ids on PowerPC. If it doesn't exist fallback to
316 * standard "reg" property.
318 if (IS_ENABLED(CONFIG_PPC) &&
319 __of_find_n_match_cpu_property(cpun,
320 "ibm,ppc-interrupt-server#s", cpu, thread))
322 if (__of_find_n_match_cpu_property(cpun, "reg", cpu, thread))
327 EXPORT_SYMBOL(of_get_cpu_node);
329 /** Checks if the given "compat" string matches one of the strings in
330 * the device's "compatible" property
332 static int __of_device_is_compatible(const struct device_node *device,
338 cp = __of_get_property(device, "compatible", &cplen);
342 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
352 /** Checks if the given "compat" string matches one of the strings in
353 * the device's "compatible" property
355 int of_device_is_compatible(const struct device_node *device,
361 raw_spin_lock_irqsave(&devtree_lock, flags);
362 res = __of_device_is_compatible(device, compat);
363 raw_spin_unlock_irqrestore(&devtree_lock, flags);
366 EXPORT_SYMBOL(of_device_is_compatible);
369 * of_machine_is_compatible - Test root of device tree for a given compatible value
370 * @compat: compatible string to look for in root node's compatible property.
372 * Returns true if the root node has the given value in its
373 * compatible property.
375 int of_machine_is_compatible(const char *compat)
377 struct device_node *root;
380 root = of_find_node_by_path("/");
382 rc = of_device_is_compatible(root, compat);
387 EXPORT_SYMBOL(of_machine_is_compatible);
390 * __of_device_is_available - check if a device is available for use
392 * @device: Node to check for availability, with locks already held
394 * Returns 1 if the status property is absent or set to "okay" or "ok",
397 static int __of_device_is_available(const struct device_node *device)
402 status = __of_get_property(device, "status", &statlen);
407 if (!strcmp(status, "okay") || !strcmp(status, "ok"))
415 * of_device_is_available - check if a device is available for use
417 * @device: Node to check for availability
419 * Returns 1 if the status property is absent or set to "okay" or "ok",
422 int of_device_is_available(const struct device_node *device)
427 raw_spin_lock_irqsave(&devtree_lock, flags);
428 res = __of_device_is_available(device);
429 raw_spin_unlock_irqrestore(&devtree_lock, flags);
433 EXPORT_SYMBOL(of_device_is_available);
436 * of_get_parent - Get a node's parent if any
437 * @node: Node to get parent
439 * Returns a node pointer with refcount incremented, use
440 * of_node_put() on it when done.
442 struct device_node *of_get_parent(const struct device_node *node)
444 struct device_node *np;
450 raw_spin_lock_irqsave(&devtree_lock, flags);
451 np = of_node_get(node->parent);
452 raw_spin_unlock_irqrestore(&devtree_lock, flags);
455 EXPORT_SYMBOL(of_get_parent);
458 * of_get_next_parent - Iterate to a node's parent
459 * @node: Node to get parent of
461 * This is like of_get_parent() except that it drops the
462 * refcount on the passed node, making it suitable for iterating
463 * through a node's parents.
465 * Returns a node pointer with refcount incremented, use
466 * of_node_put() on it when done.
468 struct device_node *of_get_next_parent(struct device_node *node)
470 struct device_node *parent;
476 raw_spin_lock_irqsave(&devtree_lock, flags);
477 parent = of_node_get(node->parent);
479 raw_spin_unlock_irqrestore(&devtree_lock, flags);
482 EXPORT_SYMBOL(of_get_next_parent);
485 * of_get_next_child - Iterate a node childs
487 * @prev: previous child of the parent node, or NULL to get first
489 * Returns a node pointer with refcount incremented, use
490 * of_node_put() on it when done.
492 struct device_node *of_get_next_child(const struct device_node *node,
493 struct device_node *prev)
495 struct device_node *next;
498 raw_spin_lock_irqsave(&devtree_lock, flags);
499 next = prev ? prev->sibling : node->child;
500 for (; next; next = next->sibling)
501 if (of_node_get(next))
504 raw_spin_unlock_irqrestore(&devtree_lock, flags);
507 EXPORT_SYMBOL(of_get_next_child);
510 * of_get_next_available_child - Find the next available child node
512 * @prev: previous child of the parent node, or NULL to get first
514 * This function is like of_get_next_child(), except that it
515 * automatically skips any disabled nodes (i.e. status = "disabled").
517 struct device_node *of_get_next_available_child(const struct device_node *node,
518 struct device_node *prev)
520 struct device_node *next;
523 raw_spin_lock_irqsave(&devtree_lock, flags);
524 next = prev ? prev->sibling : node->child;
525 for (; next; next = next->sibling) {
526 if (!__of_device_is_available(next))
528 if (of_node_get(next))
532 raw_spin_unlock_irqrestore(&devtree_lock, flags);
535 EXPORT_SYMBOL(of_get_next_available_child);
538 * of_get_child_by_name - Find the child node by name for a given parent
540 * @name: child name to look for.
542 * This function looks for child node for given matching name
544 * Returns a node pointer if found, with refcount incremented, use
545 * of_node_put() on it when done.
546 * Returns NULL if node is not found.
548 struct device_node *of_get_child_by_name(const struct device_node *node,
551 struct device_node *child;
553 for_each_child_of_node(node, child)
554 if (child->name && (of_node_cmp(child->name, name) == 0))
558 EXPORT_SYMBOL(of_get_child_by_name);
561 * of_find_node_by_path - Find a node matching a full OF path
562 * @path: The full path to match
564 * Returns a node pointer with refcount incremented, use
565 * of_node_put() on it when done.
567 struct device_node *of_find_node_by_path(const char *path)
569 struct device_node *np = of_allnodes;
572 raw_spin_lock_irqsave(&devtree_lock, flags);
573 for (; np; np = np->allnext) {
574 if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
578 raw_spin_unlock_irqrestore(&devtree_lock, flags);
581 EXPORT_SYMBOL(of_find_node_by_path);
584 * of_find_node_by_name - Find a node by its "name" property
585 * @from: The node to start searching from or NULL, the node
586 * you pass will not be searched, only the next one
587 * will; typically, you pass what the previous call
588 * returned. of_node_put() will be called on it
589 * @name: The name string to match against
591 * Returns a node pointer with refcount incremented, use
592 * of_node_put() on it when done.
594 struct device_node *of_find_node_by_name(struct device_node *from,
597 struct device_node *np;
600 raw_spin_lock_irqsave(&devtree_lock, flags);
601 np = from ? from->allnext : of_allnodes;
602 for (; np; np = np->allnext)
603 if (np->name && (of_node_cmp(np->name, name) == 0)
607 raw_spin_unlock_irqrestore(&devtree_lock, flags);
610 EXPORT_SYMBOL(of_find_node_by_name);
613 * of_find_node_by_type - Find a node by its "device_type" property
614 * @from: The node to start searching from, or NULL to start searching
615 * the entire device tree. The node you pass will not be
616 * searched, only the next one will; typically, you pass
617 * what the previous call returned. of_node_put() will be
618 * called on from for you.
619 * @type: The type string to match against
621 * Returns a node pointer with refcount incremented, use
622 * of_node_put() on it when done.
624 struct device_node *of_find_node_by_type(struct device_node *from,
627 struct device_node *np;
630 raw_spin_lock_irqsave(&devtree_lock, flags);
631 np = from ? from->allnext : of_allnodes;
632 for (; np; np = np->allnext)
633 if (np->type && (of_node_cmp(np->type, type) == 0)
637 raw_spin_unlock_irqrestore(&devtree_lock, flags);
640 EXPORT_SYMBOL(of_find_node_by_type);
643 * of_find_compatible_node - Find a node based on type and one of the
644 * tokens in its "compatible" property
645 * @from: The node to start searching from or NULL, the node
646 * you pass will not be searched, only the next one
647 * will; typically, you pass what the previous call
648 * returned. of_node_put() will be called on it
649 * @type: The type string to match "device_type" or NULL to ignore
650 * @compatible: The string to match to one of the tokens in the device
653 * Returns a node pointer with refcount incremented, use
654 * of_node_put() on it when done.
656 struct device_node *of_find_compatible_node(struct device_node *from,
657 const char *type, const char *compatible)
659 struct device_node *np;
662 raw_spin_lock_irqsave(&devtree_lock, flags);
663 np = from ? from->allnext : of_allnodes;
664 for (; np; np = np->allnext) {
666 && !(np->type && (of_node_cmp(np->type, type) == 0)))
668 if (__of_device_is_compatible(np, compatible) &&
673 raw_spin_unlock_irqrestore(&devtree_lock, flags);
676 EXPORT_SYMBOL(of_find_compatible_node);
679 * of_find_node_with_property - Find a node which has a property with
681 * @from: The node to start searching from or NULL, the node
682 * you pass will not be searched, only the next one
683 * will; typically, you pass what the previous call
684 * returned. of_node_put() will be called on it
685 * @prop_name: The name of the property to look for.
687 * Returns a node pointer with refcount incremented, use
688 * of_node_put() on it when done.
690 struct device_node *of_find_node_with_property(struct device_node *from,
691 const char *prop_name)
693 struct device_node *np;
697 raw_spin_lock_irqsave(&devtree_lock, flags);
698 np = from ? from->allnext : of_allnodes;
699 for (; np; np = np->allnext) {
700 for (pp = np->properties; pp; pp = pp->next) {
701 if (of_prop_cmp(pp->name, prop_name) == 0) {
709 raw_spin_unlock_irqrestore(&devtree_lock, flags);
712 EXPORT_SYMBOL(of_find_node_with_property);
715 const struct of_device_id *__of_match_node(const struct of_device_id *matches,
716 const struct device_node *node)
721 while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
723 if (matches->name[0])
725 && !strcmp(matches->name, node->name);
726 if (matches->type[0])
728 && !strcmp(matches->type, node->type);
729 if (matches->compatible[0])
730 match &= __of_device_is_compatible(node,
731 matches->compatible);
740 * of_match_node - Tell if an device_node has a matching of_match structure
741 * @matches: array of of device match structures to search in
742 * @node: the of device structure to match against
744 * Low level utility function used by device matching.
746 const struct of_device_id *of_match_node(const struct of_device_id *matches,
747 const struct device_node *node)
749 const struct of_device_id *match;
752 raw_spin_lock_irqsave(&devtree_lock, flags);
753 match = __of_match_node(matches, node);
754 raw_spin_unlock_irqrestore(&devtree_lock, flags);
757 EXPORT_SYMBOL(of_match_node);
760 * of_find_matching_node_and_match - Find a node based on an of_device_id
762 * @from: The node to start searching from or NULL, the node
763 * you pass will not be searched, only the next one
764 * will; typically, you pass what the previous call
765 * returned. of_node_put() will be called on it
766 * @matches: array of of device match structures to search in
767 * @match Updated to point at the matches entry which matched
769 * Returns a node pointer with refcount incremented, use
770 * of_node_put() on it when done.
772 struct device_node *of_find_matching_node_and_match(struct device_node *from,
773 const struct of_device_id *matches,
774 const struct of_device_id **match)
776 struct device_node *np;
777 const struct of_device_id *m;
783 raw_spin_lock_irqsave(&devtree_lock, flags);
784 np = from ? from->allnext : of_allnodes;
785 for (; np; np = np->allnext) {
786 m = __of_match_node(matches, np);
787 if (m && of_node_get(np)) {
794 raw_spin_unlock_irqrestore(&devtree_lock, flags);
797 EXPORT_SYMBOL(of_find_matching_node_and_match);
800 * of_modalias_node - Lookup appropriate modalias for a device node
801 * @node: pointer to a device tree node
802 * @modalias: Pointer to buffer that modalias value will be copied into
803 * @len: Length of modalias value
805 * Based on the value of the compatible property, this routine will attempt
806 * to choose an appropriate modalias value for a particular device tree node.
807 * It does this by stripping the manufacturer prefix (as delimited by a ',')
808 * from the first entry in the compatible list property.
810 * This routine returns 0 on success, <0 on failure.
812 int of_modalias_node(struct device_node *node, char *modalias, int len)
814 const char *compatible, *p;
817 compatible = of_get_property(node, "compatible", &cplen);
818 if (!compatible || strlen(compatible) > cplen)
820 p = strchr(compatible, ',');
821 strlcpy(modalias, p ? p + 1 : compatible, len);
824 EXPORT_SYMBOL_GPL(of_modalias_node);
827 * of_find_node_by_phandle - Find a node given a phandle
828 * @handle: phandle of the node to find
830 * Returns a node pointer with refcount incremented, use
831 * of_node_put() on it when done.
833 struct device_node *of_find_node_by_phandle(phandle handle)
835 struct device_node *np;
838 raw_spin_lock_irqsave(&devtree_lock, flags);
839 for (np = of_allnodes; np; np = np->allnext)
840 if (np->phandle == handle)
843 raw_spin_unlock_irqrestore(&devtree_lock, flags);
846 EXPORT_SYMBOL(of_find_node_by_phandle);
849 * of_find_property_value_of_size
851 * @np: device node from which the property value is to be read.
852 * @propname: name of the property to be searched.
853 * @len: requested length of property value
855 * Search for a property in a device node and valid the requested size.
856 * Returns the property value on success, -EINVAL if the property does not
857 * exist, -ENODATA if property does not have a value, and -EOVERFLOW if the
858 * property data isn't large enough.
861 static void *of_find_property_value_of_size(const struct device_node *np,
862 const char *propname, u32 len)
864 struct property *prop = of_find_property(np, propname, NULL);
867 return ERR_PTR(-EINVAL);
869 return ERR_PTR(-ENODATA);
870 if (len > prop->length)
871 return ERR_PTR(-EOVERFLOW);
877 * of_property_read_u32_index - Find and read a u32 from a multi-value property.
879 * @np: device node from which the property value is to be read.
880 * @propname: name of the property to be searched.
881 * @index: index of the u32 in the list of values
882 * @out_value: pointer to return value, modified only if no error.
884 * Search for a property in a device node and read nth 32-bit value from
885 * it. Returns 0 on success, -EINVAL if the property does not exist,
886 * -ENODATA if property does not have a value, and -EOVERFLOW if the
887 * property data isn't large enough.
889 * The out_value is modified only if a valid u32 value can be decoded.
891 int of_property_read_u32_index(const struct device_node *np,
892 const char *propname,
893 u32 index, u32 *out_value)
895 const u32 *val = of_find_property_value_of_size(np, propname,
896 ((index + 1) * sizeof(*out_value)));
901 *out_value = be32_to_cpup(((__be32 *)val) + index);
904 EXPORT_SYMBOL_GPL(of_property_read_u32_index);
907 * of_property_read_u8_array - Find and read an array of u8 from a property.
909 * @np: device node from which the property value is to be read.
910 * @propname: name of the property to be searched.
911 * @out_value: pointer to return value, modified only if return value is 0.
912 * @sz: number of array elements to read
914 * Search for a property in a device node and read 8-bit value(s) from
915 * it. Returns 0 on success, -EINVAL if the property does not exist,
916 * -ENODATA if property does not have a value, and -EOVERFLOW if the
917 * property data isn't large enough.
919 * dts entry of array should be like:
920 * property = /bits/ 8 <0x50 0x60 0x70>;
922 * The out_value is modified only if a valid u8 value can be decoded.
924 int of_property_read_u8_array(const struct device_node *np,
925 const char *propname, u8 *out_values, size_t sz)
927 const u8 *val = of_find_property_value_of_size(np, propname,
928 (sz * sizeof(*out_values)));
934 *out_values++ = *val++;
937 EXPORT_SYMBOL_GPL(of_property_read_u8_array);
940 int of_property_read_u8_array_tp(const struct device_node *np,
941 const char *propname, u8 *out_values, size_t sz)
943 const __be32 *val = of_find_property_value_of_size(np, propname,
944 (sz * sizeof(*out_values)));
950 *out_values++ = (unsigned char)(be32_to_cpup(val++));
953 EXPORT_SYMBOL_GPL(of_property_read_u8_array_tp);
958 * of_property_read_u16_array - Find and read an array of u16 from a property.
960 * @np: device node from which the property value is to be read.
961 * @propname: name of the property to be searched.
962 * @out_value: pointer to return value, modified only if return value is 0.
963 * @sz: number of array elements to read
965 * Search for a property in a device node and read 16-bit value(s) from
966 * it. Returns 0 on success, -EINVAL if the property does not exist,
967 * -ENODATA if property does not have a value, and -EOVERFLOW if the
968 * property data isn't large enough.
970 * dts entry of array should be like:
971 * property = /bits/ 16 <0x5000 0x6000 0x7000>;
973 * The out_value is modified only if a valid u16 value can be decoded.
975 int of_property_read_u16_array(const struct device_node *np,
976 const char *propname, u16 *out_values, size_t sz)
978 const __be16 *val = of_find_property_value_of_size(np, propname,
979 (sz * sizeof(*out_values)));
985 *out_values++ = be16_to_cpup(val++);
988 EXPORT_SYMBOL_GPL(of_property_read_u16_array);
991 * of_property_read_u32_array - Find and read an array of 32 bit integers
994 * @np: device node from which the property value is to be read.
995 * @propname: name of the property to be searched.
996 * @out_value: pointer to return value, modified only if return value is 0.
997 * @sz: number of array elements to read
999 * Search for a property in a device node and read 32-bit value(s) from
1000 * it. Returns 0 on success, -EINVAL if the property does not exist,
1001 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1002 * property data isn't large enough.
1004 * The out_value is modified only if a valid u32 value can be decoded.
1006 int of_property_read_u32_array(const struct device_node *np,
1007 const char *propname, u32 *out_values,
1010 const __be32 *val = of_find_property_value_of_size(np, propname,
1011 (sz * sizeof(*out_values)));
1014 return PTR_ERR(val);
1017 *out_values++ = be32_to_cpup(val++);
1020 EXPORT_SYMBOL_GPL(of_property_read_u32_array);
1023 * of_property_read_u64 - Find and read a 64 bit integer from a property
1024 * @np: device node from which the property value is to be read.
1025 * @propname: name of the property to be searched.
1026 * @out_value: pointer to return value, modified only if return value is 0.
1028 * Search for a property in a device node and read a 64-bit value from
1029 * it. Returns 0 on success, -EINVAL if the property does not exist,
1030 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1031 * property data isn't large enough.
1033 * The out_value is modified only if a valid u64 value can be decoded.
1035 int of_property_read_u64(const struct device_node *np, const char *propname,
1038 const __be32 *val = of_find_property_value_of_size(np, propname,
1039 sizeof(*out_value));
1042 return PTR_ERR(val);
1044 *out_value = of_read_number(val, 2);
1047 EXPORT_SYMBOL_GPL(of_property_read_u64);
1050 * of_property_read_string - Find and read a string from a property
1051 * @np: device node from which the property value is to be read.
1052 * @propname: name of the property to be searched.
1053 * @out_string: pointer to null terminated return string, modified only if
1054 * return value is 0.
1056 * Search for a property in a device tree node and retrieve a null
1057 * terminated string value (pointer to data, not a copy). Returns 0 on
1058 * success, -EINVAL if the property does not exist, -ENODATA if property
1059 * does not have a value, and -EILSEQ if the string is not null-terminated
1060 * within the length of the property data.
1062 * The out_string pointer is modified only if a valid string can be decoded.
1064 int of_property_read_string(struct device_node *np, const char *propname,
1065 const char **out_string)
1067 struct property *prop = of_find_property(np, propname, NULL);
1072 if (strnlen(prop->value, prop->length) >= prop->length)
1074 *out_string = prop->value;
1077 EXPORT_SYMBOL_GPL(of_property_read_string);
1080 * of_property_read_string_index - Find and read a string from a multiple
1082 * @np: device node from which the property value is to be read.
1083 * @propname: name of the property to be searched.
1084 * @index: index of the string in the list of strings
1085 * @out_string: pointer to null terminated return string, modified only if
1086 * return value is 0.
1088 * Search for a property in a device tree node and retrieve a null
1089 * terminated string value (pointer to data, not a copy) in the list of strings
1090 * contained in that property.
1091 * Returns 0 on success, -EINVAL if the property does not exist, -ENODATA if
1092 * property does not have a value, and -EILSEQ if the string is not
1093 * null-terminated within the length of the property data.
1095 * The out_string pointer is modified only if a valid string can be decoded.
1097 int of_property_read_string_index(struct device_node *np, const char *propname,
1098 int index, const char **output)
1100 struct property *prop = of_find_property(np, propname, NULL);
1102 size_t l = 0, total = 0;
1109 if (strnlen(prop->value, prop->length) >= prop->length)
1114 for (i = 0; total < prop->length; total += l, p += l) {
1123 EXPORT_SYMBOL_GPL(of_property_read_string_index);
1126 * of_property_match_string() - Find string in a list and return index
1127 * @np: pointer to node containing string list property
1128 * @propname: string list property name
1129 * @string: pointer to string to search for in string list
1131 * This function searches a string list property and returns the index
1132 * of a specific string value.
1134 int of_property_match_string(struct device_node *np, const char *propname,
1137 struct property *prop = of_find_property(np, propname, NULL);
1140 const char *p, *end;
1148 end = p + prop->length;
1150 for (i = 0; p < end; i++, p += l) {
1154 pr_debug("comparing %s with %s\n", string, p);
1155 if (strcmp(string, p) == 0)
1156 return i; /* Found it; return index */
1160 EXPORT_SYMBOL_GPL(of_property_match_string);
1163 * of_property_count_strings - Find and return the number of strings from a
1164 * multiple strings property.
1165 * @np: device node from which the property value is to be read.
1166 * @propname: name of the property to be searched.
1168 * Search for a property in a device tree node and retrieve the number of null
1169 * terminated string contain in it. Returns the number of strings on
1170 * success, -EINVAL if the property does not exist, -ENODATA if property
1171 * does not have a value, and -EILSEQ if the string is not null-terminated
1172 * within the length of the property data.
1174 int of_property_count_strings(struct device_node *np, const char *propname)
1176 struct property *prop = of_find_property(np, propname, NULL);
1178 size_t l = 0, total = 0;
1185 if (strnlen(prop->value, prop->length) >= prop->length)
1190 for (i = 0; total < prop->length; total += l, p += l, i++)
1195 EXPORT_SYMBOL_GPL(of_property_count_strings);
1198 * of_parse_phandle - Resolve a phandle property to a device_node pointer
1199 * @np: Pointer to device node holding phandle property
1200 * @phandle_name: Name of property holding a phandle value
1201 * @index: For properties holding a table of phandles, this is the index into
1204 * Returns the device_node pointer with refcount incremented. Use
1205 * of_node_put() on it when done.
1207 struct device_node *of_parse_phandle(const struct device_node *np,
1208 const char *phandle_name, int index)
1210 const __be32 *phandle;
1213 phandle = of_get_property(np, phandle_name, &size);
1214 if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
1217 return of_find_node_by_phandle(be32_to_cpup(phandle + index));
1219 EXPORT_SYMBOL(of_parse_phandle);
1222 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
1223 * @np: pointer to a device tree node containing a list
1224 * @list_name: property name that contains a list
1225 * @cells_name: property name that specifies phandles' arguments count
1226 * @index: index of a phandle to parse out
1227 * @out_args: optional pointer to output arguments structure (will be filled)
1229 * This function is useful to parse lists of phandles and their arguments.
1230 * Returns 0 on success and fills out_args, on error returns appropriate
1233 * Caller is responsible to call of_node_put() on the returned out_args->node
1239 * #list-cells = <2>;
1243 * #list-cells = <1>;
1247 * list = <&phandle1 1 2 &phandle2 3>;
1250 * To get a device_node of the `node2' node you may call this:
1251 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
1253 static int __of_parse_phandle_with_args(const struct device_node *np,
1254 const char *list_name,
1255 const char *cells_name, int index,
1256 struct of_phandle_args *out_args)
1258 const __be32 *list, *list_end;
1259 int rc = 0, size, cur_index = 0;
1261 struct device_node *node = NULL;
1264 /* Retrieve the phandle list property */
1265 list = of_get_property(np, list_name, &size);
1268 list_end = list + size / sizeof(*list);
1270 /* Loop over the phandles until all the requested entry is found */
1271 while (list < list_end) {
1276 * If phandle is 0, then it is an empty entry with no
1277 * arguments. Skip forward to the next entry.
1279 phandle = be32_to_cpup(list++);
1282 * Find the provider node and parse the #*-cells
1283 * property to determine the argument length
1285 node = of_find_node_by_phandle(phandle);
1287 pr_err("%s: could not find phandle\n",
1291 if (of_property_read_u32(node, cells_name, &count)) {
1292 pr_err("%s: could not get %s for %s\n",
1293 np->full_name, cells_name,
1299 * Make sure that the arguments actually fit in the
1300 * remaining property data length
1302 if (list + count > list_end) {
1303 pr_err("%s: arguments longer than property\n",
1310 * All of the error cases above bail out of the loop, so at
1311 * this point, the parsing is successful. If the requested
1312 * index matches, then fill the out_args structure and return,
1313 * or return -ENOENT for an empty entry.
1316 if (cur_index == index) {
1322 if (WARN_ON(count > MAX_PHANDLE_ARGS))
1323 count = MAX_PHANDLE_ARGS;
1324 out_args->np = node;
1325 out_args->args_count = count;
1326 for (i = 0; i < count; i++)
1327 out_args->args[i] = be32_to_cpup(list++);
1332 /* Found it! return success */
1343 * Unlock node before returning result; will be one of:
1344 * -ENOENT : index is for empty phandle
1345 * -EINVAL : parsing error on data
1346 * [1..n] : Number of phandle (count mode; when index = -1)
1348 rc = index < 0 ? cur_index : -ENOENT;
1355 int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
1356 const char *cells_name, int index,
1357 struct of_phandle_args *out_args)
1361 return __of_parse_phandle_with_args(np, list_name, cells_name, index, out_args);
1363 EXPORT_SYMBOL(of_parse_phandle_with_args);
1366 * of_count_phandle_with_args() - Find the number of phandles references in a property
1367 * @np: pointer to a device tree node containing a list
1368 * @list_name: property name that contains a list
1369 * @cells_name: property name that specifies phandles' arguments count
1371 * Returns the number of phandle + argument tuples within a property. It
1372 * is a typical pattern to encode a list of phandle and variable
1373 * arguments into a single property. The number of arguments is encoded
1374 * by a property in the phandle-target node. For example, a gpios
1375 * property would contain a list of GPIO specifies consisting of a
1376 * phandle and 1 or more arguments. The number of arguments are
1377 * determined by the #gpio-cells property in the node pointed to by the
1380 int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
1381 const char *cells_name)
1383 return __of_parse_phandle_with_args(np, list_name, cells_name, -1, NULL);
1385 EXPORT_SYMBOL(of_count_phandle_with_args);
1387 #if defined(CONFIG_OF_DYNAMIC)
1388 static int of_property_notify(int action, struct device_node *np,
1389 struct property *prop)
1391 struct of_prop_reconfig pr;
1395 return of_reconfig_notify(action, &pr);
1398 static int of_property_notify(int action, struct device_node *np,
1399 struct property *prop)
1406 * of_add_property - Add a property to a node
1408 int of_add_property(struct device_node *np, struct property *prop)
1410 struct property **next;
1411 unsigned long flags;
1414 rc = of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop);
1419 raw_spin_lock_irqsave(&devtree_lock, flags);
1420 next = &np->properties;
1422 if (strcmp(prop->name, (*next)->name) == 0) {
1423 /* duplicate ! don't insert it */
1424 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1427 next = &(*next)->next;
1430 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1432 #ifdef CONFIG_PROC_DEVICETREE
1433 /* try to add to proc as well if it was initialized */
1435 proc_device_tree_add_prop(np->pde, prop);
1436 #endif /* CONFIG_PROC_DEVICETREE */
1442 * of_remove_property - Remove a property from a node.
1444 * Note that we don't actually remove it, since we have given out
1445 * who-knows-how-many pointers to the data using get-property.
1446 * Instead we just move the property to the "dead properties"
1447 * list, so it won't be found any more.
1449 int of_remove_property(struct device_node *np, struct property *prop)
1451 struct property **next;
1452 unsigned long flags;
1456 rc = of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop);
1460 raw_spin_lock_irqsave(&devtree_lock, flags);
1461 next = &np->properties;
1463 if (*next == prop) {
1464 /* found the node */
1466 prop->next = np->deadprops;
1467 np->deadprops = prop;
1471 next = &(*next)->next;
1473 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1478 #ifdef CONFIG_PROC_DEVICETREE
1479 /* try to remove the proc node as well */
1481 proc_device_tree_remove_prop(np->pde, prop);
1482 #endif /* CONFIG_PROC_DEVICETREE */
1488 * of_update_property - Update a property in a node, if the property does
1489 * not exist, add it.
1491 * Note that we don't actually remove it, since we have given out
1492 * who-knows-how-many pointers to the data using get-property.
1493 * Instead we just move the property to the "dead properties" list,
1494 * and add the new property to the property list
1496 int of_update_property(struct device_node *np, struct property *newprop)
1498 struct property **next, *oldprop;
1499 unsigned long flags;
1502 rc = of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop);
1509 oldprop = of_find_property(np, newprop->name, NULL);
1511 return of_add_property(np, newprop);
1513 raw_spin_lock_irqsave(&devtree_lock, flags);
1514 next = &np->properties;
1516 if (*next == oldprop) {
1517 /* found the node */
1518 newprop->next = oldprop->next;
1520 oldprop->next = np->deadprops;
1521 np->deadprops = oldprop;
1525 next = &(*next)->next;
1527 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1532 #ifdef CONFIG_PROC_DEVICETREE
1533 /* try to add to proc as well if it was initialized */
1535 proc_device_tree_update_prop(np->pde, newprop, oldprop);
1536 #endif /* CONFIG_PROC_DEVICETREE */
1541 #if defined(CONFIG_OF_DYNAMIC)
1543 * Support for dynamic device trees.
1545 * On some platforms, the device tree can be manipulated at runtime.
1546 * The routines in this section support adding, removing and changing
1547 * device tree nodes.
1550 static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
1552 int of_reconfig_notifier_register(struct notifier_block *nb)
1554 return blocking_notifier_chain_register(&of_reconfig_chain, nb);
1556 EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
1558 int of_reconfig_notifier_unregister(struct notifier_block *nb)
1560 return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
1562 EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
1564 int of_reconfig_notify(unsigned long action, void *p)
1568 rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
1569 return notifier_to_errno(rc);
1572 #ifdef CONFIG_PROC_DEVICETREE
1573 static void of_add_proc_dt_entry(struct device_node *dn)
1575 struct proc_dir_entry *ent;
1577 ent = proc_mkdir(strrchr(dn->full_name, '/') + 1, dn->parent->pde);
1579 proc_device_tree_add_node(dn, ent);
1582 static void of_add_proc_dt_entry(struct device_node *dn)
1589 * of_attach_node - Plug a device node into the tree and global list.
1591 int of_attach_node(struct device_node *np)
1593 unsigned long flags;
1596 rc = of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, np);
1600 raw_spin_lock_irqsave(&devtree_lock, flags);
1601 np->sibling = np->parent->child;
1602 np->allnext = of_allnodes;
1603 np->parent->child = np;
1605 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1607 of_add_proc_dt_entry(np);
1611 #ifdef CONFIG_PROC_DEVICETREE
1612 static void of_remove_proc_dt_entry(struct device_node *dn)
1614 proc_remove(dn->pde);
1617 static void of_remove_proc_dt_entry(struct device_node *dn)
1624 * of_detach_node - "Unplug" a node from the device tree.
1626 * The caller must hold a reference to the node. The memory associated with
1627 * the node is not freed until its refcount goes to zero.
1629 int of_detach_node(struct device_node *np)
1631 struct device_node *parent;
1632 unsigned long flags;
1635 rc = of_reconfig_notify(OF_RECONFIG_DETACH_NODE, np);
1639 raw_spin_lock_irqsave(&devtree_lock, flags);
1641 if (of_node_check_flag(np, OF_DETACHED)) {
1642 /* someone already detached it */
1643 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1647 parent = np->parent;
1649 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1653 if (of_allnodes == np)
1654 of_allnodes = np->allnext;
1656 struct device_node *prev;
1657 for (prev = of_allnodes;
1658 prev->allnext != np;
1659 prev = prev->allnext)
1661 prev->allnext = np->allnext;
1664 if (parent->child == np)
1665 parent->child = np->sibling;
1667 struct device_node *prevsib;
1668 for (prevsib = np->parent->child;
1669 prevsib->sibling != np;
1670 prevsib = prevsib->sibling)
1672 prevsib->sibling = np->sibling;
1675 of_node_set_flag(np, OF_DETACHED);
1676 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1678 of_remove_proc_dt_entry(np);
1681 #endif /* defined(CONFIG_OF_DYNAMIC) */
1683 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1684 int id, const char *stem, int stem_len)
1688 strncpy(ap->stem, stem, stem_len);
1689 ap->stem[stem_len] = 0;
1690 list_add_tail(&ap->link, &aliases_lookup);
1691 pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
1692 ap->alias, ap->stem, ap->id, of_node_full_name(np));
1696 * of_alias_scan - Scan all properties of 'aliases' node
1698 * The function scans all the properties of 'aliases' node and populate
1699 * the the global lookup table with the properties. It returns the
1700 * number of alias_prop found, or error code in error case.
1702 * @dt_alloc: An allocator that provides a virtual address to memory
1703 * for the resulting tree
1705 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1707 struct property *pp;
1709 of_chosen = of_find_node_by_path("/chosen");
1710 if (of_chosen == NULL)
1711 of_chosen = of_find_node_by_path("/chosen@0");
1716 name = of_get_property(of_chosen, "linux,stdout-path", NULL);
1718 of_stdout = of_find_node_by_path(name);
1721 of_aliases = of_find_node_by_path("/aliases");
1725 for_each_property_of_node(of_aliases, pp) {
1726 const char *start = pp->name;
1727 const char *end = start + strlen(start);
1728 struct device_node *np;
1729 struct alias_prop *ap;
1732 /* Skip those we do not want to proceed */
1733 if (!strcmp(pp->name, "name") ||
1734 !strcmp(pp->name, "phandle") ||
1735 !strcmp(pp->name, "linux,phandle"))
1738 np = of_find_node_by_path(pp->value);
1742 /* walk the alias backwards to extract the id and work out
1743 * the 'stem' string */
1744 while (isdigit(*(end-1)) && end > start)
1748 if (kstrtoint(end, 10, &id) < 0)
1751 /* Allocate an alias_prop with enough space for the stem */
1752 ap = dt_alloc(sizeof(*ap) + len + 1, 4);
1755 memset(ap, 0, sizeof(*ap) + len + 1);
1757 of_alias_add(ap, np, id, start, len);
1762 * of_alias_get_id - Get alias id for the given device_node
1763 * @np: Pointer to the given device_node
1764 * @stem: Alias stem of the given device_node
1766 * The function travels the lookup table to get alias id for the given
1767 * device_node and alias stem. It returns the alias id if find it.
1769 int of_alias_get_id(struct device_node *np, const char *stem)
1771 struct alias_prop *app;
1774 mutex_lock(&of_aliases_mutex);
1775 list_for_each_entry(app, &aliases_lookup, link) {
1776 if (strcmp(app->stem, stem) != 0)
1779 if (np == app->np) {
1784 mutex_unlock(&of_aliases_mutex);
1788 EXPORT_SYMBOL_GPL(of_alias_get_id);
1790 const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
1793 const void *curv = cur;
1803 curv += sizeof(*cur);
1804 if (curv >= prop->value + prop->length)
1808 *pu = be32_to_cpup(curv);
1811 EXPORT_SYMBOL_GPL(of_prop_next_u32);
1813 const char *of_prop_next_string(struct property *prop, const char *cur)
1815 const void *curv = cur;
1823 curv += strlen(cur) + 1;
1824 if (curv >= prop->value + prop->length)
1829 EXPORT_SYMBOL_GPL(of_prop_next_string);
1832 * of_device_is_stdout_path - check if a device node matches the
1833 * linux,stdout-path property
1835 * Check if this device node matches the linux,stdout-path property
1836 * in the chosen node. return true if yes, false otherwise.
1838 int of_device_is_stdout_path(struct device_node *dn)
1843 return of_stdout == dn;
1845 EXPORT_SYMBOL_GPL(of_device_is_stdout_path);