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/console.h>
21 #include <linux/ctype.h>
22 #include <linux/cpu.h>
23 #include <linux/module.h>
25 #include <linux/of_graph.h>
26 #include <linux/spinlock.h>
27 #include <linux/slab.h>
28 #include <linux/string.h>
29 #include <linux/proc_fs.h>
31 #include "of_private.h"
33 LIST_HEAD(aliases_lookup);
35 struct device_node *of_root;
36 EXPORT_SYMBOL(of_root);
37 struct device_node *of_chosen;
38 struct device_node *of_aliases;
39 struct device_node *of_stdout;
40 static const char *of_stdout_options;
45 * Used to protect the of_aliases, to hold off addition of nodes to sysfs.
46 * This mutex must be held whenever modifications are being made to the
47 * device tree. The of_{attach,detach}_node() and
48 * of_{add,remove,update}_property() helpers make sure this happens.
50 DEFINE_MUTEX(of_mutex);
52 /* use when traversing tree through the child, sibling,
53 * or parent members of struct device_node.
55 DEFINE_RAW_SPINLOCK(devtree_lock);
57 int of_n_addr_cells(struct device_node *np)
64 ip = of_get_property(np, "#address-cells", NULL);
66 return be32_to_cpup(ip);
68 /* No #address-cells property for the root node */
69 return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
71 EXPORT_SYMBOL(of_n_addr_cells);
73 int of_n_size_cells(struct device_node *np)
80 ip = of_get_property(np, "#size-cells", NULL);
82 return be32_to_cpup(ip);
84 /* No #size-cells property for the root node */
85 return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
87 EXPORT_SYMBOL(of_n_size_cells);
90 int __weak of_node_to_nid(struct device_node *np)
92 return numa_node_id();
96 #ifndef CONFIG_OF_DYNAMIC
97 static void of_node_release(struct kobject *kobj)
99 /* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
101 #endif /* CONFIG_OF_DYNAMIC */
103 struct kobj_type of_node_ktype = {
104 .release = of_node_release,
107 static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
108 struct bin_attribute *bin_attr, char *buf,
109 loff_t offset, size_t count)
111 struct property *pp = container_of(bin_attr, struct property, attr);
112 return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
115 static const char *safe_name(struct kobject *kobj, const char *orig_name)
117 const char *name = orig_name;
118 struct kernfs_node *kn;
121 /* don't be a hero. After 16 tries give up */
122 while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {
124 if (name != orig_name)
126 name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
129 if (name != orig_name)
130 pr_warn("device-tree: Duplicate name in %s, renamed to \"%s\"\n",
131 kobject_name(kobj), name);
135 int __of_add_property_sysfs(struct device_node *np, struct property *pp)
139 /* Important: Don't leak passwords */
140 bool secure = strncmp(pp->name, "security-", 9) == 0;
142 if (!IS_ENABLED(CONFIG_SYSFS))
145 if (!of_kset || !of_node_is_attached(np))
148 sysfs_bin_attr_init(&pp->attr);
149 pp->attr.attr.name = safe_name(&np->kobj, pp->name);
150 pp->attr.attr.mode = secure ? S_IRUSR : S_IRUGO;
151 pp->attr.size = secure ? 0 : pp->length;
152 pp->attr.read = of_node_property_read;
154 rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
155 WARN(rc, "error adding attribute %s to node %s\n", pp->name, np->full_name);
159 int __of_attach_node_sysfs(struct device_node *np)
165 if (!IS_ENABLED(CONFIG_SYSFS))
171 np->kobj.kset = of_kset;
173 /* Nodes without parents are new top level trees */
174 rc = kobject_add(&np->kobj, NULL, "%s",
175 safe_name(&of_kset->kobj, "base"));
177 name = safe_name(&np->parent->kobj, kbasename(np->full_name));
178 if (!name || !name[0])
181 rc = kobject_add(&np->kobj, &np->parent->kobj, "%s", name);
186 for_each_property_of_node(np, pp)
187 __of_add_property_sysfs(np, pp);
192 static int __init of_init(void)
194 struct device_node *np;
196 /* Create the kset, and register existing nodes */
197 mutex_lock(&of_mutex);
198 of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj);
200 mutex_unlock(&of_mutex);
203 for_each_of_allnodes(np)
204 __of_attach_node_sysfs(np);
205 mutex_unlock(&of_mutex);
207 /* Symlink in /proc as required by userspace ABI */
209 proc_symlink("device-tree", NULL, "/sys/firmware/devicetree/base");
213 core_initcall(of_init);
215 static struct property *__of_find_property(const struct device_node *np,
216 const char *name, int *lenp)
223 for (pp = np->properties; pp; pp = pp->next) {
224 if (of_prop_cmp(pp->name, name) == 0) {
234 struct property *of_find_property(const struct device_node *np,
241 raw_spin_lock_irqsave(&devtree_lock, flags);
242 pp = __of_find_property(np, name, lenp);
243 raw_spin_unlock_irqrestore(&devtree_lock, flags);
247 EXPORT_SYMBOL(of_find_property);
249 struct device_node *__of_find_all_nodes(struct device_node *prev)
251 struct device_node *np;
254 } else if (prev->child) {
257 /* Walk back up looking for a sibling, or the end of the structure */
259 while (np->parent && !np->sibling)
261 np = np->sibling; /* Might be null at the end of the tree */
267 * of_find_all_nodes - Get next node in global list
268 * @prev: Previous node or NULL to start iteration
269 * of_node_put() will be called on it
271 * Returns a node pointer with refcount incremented, use
272 * of_node_put() on it when done.
274 struct device_node *of_find_all_nodes(struct device_node *prev)
276 struct device_node *np;
279 raw_spin_lock_irqsave(&devtree_lock, flags);
280 np = __of_find_all_nodes(prev);
283 raw_spin_unlock_irqrestore(&devtree_lock, flags);
286 EXPORT_SYMBOL(of_find_all_nodes);
289 * Find a property with a given name for a given node
290 * and return the value.
292 const void *__of_get_property(const struct device_node *np,
293 const char *name, int *lenp)
295 struct property *pp = __of_find_property(np, name, lenp);
297 return pp ? pp->value : NULL;
301 * Find a property with a given name for a given node
302 * and return the value.
304 const void *of_get_property(const struct device_node *np, const char *name,
307 struct property *pp = of_find_property(np, name, lenp);
309 return pp ? pp->value : NULL;
311 EXPORT_SYMBOL(of_get_property);
314 * arch_match_cpu_phys_id - Match the given logical CPU and physical id
316 * @cpu: logical cpu index of a core/thread
317 * @phys_id: physical identifier of a core/thread
319 * CPU logical to physical index mapping is architecture specific.
320 * However this __weak function provides a default match of physical
321 * id to logical cpu index. phys_id provided here is usually values read
322 * from the device tree which must match the hardware internal registers.
324 * Returns true if the physical identifier and the logical cpu index
325 * correspond to the same core/thread, false otherwise.
327 bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id)
329 return (u32)phys_id == cpu;
333 * Checks if the given "prop_name" property holds the physical id of the
334 * core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not
335 * NULL, local thread number within the core is returned in it.
337 static bool __of_find_n_match_cpu_property(struct device_node *cpun,
338 const char *prop_name, int cpu, unsigned int *thread)
341 int ac, prop_len, tid;
344 ac = of_n_addr_cells(cpun);
345 cell = of_get_property(cpun, prop_name, &prop_len);
348 prop_len /= sizeof(*cell) * ac;
349 for (tid = 0; tid < prop_len; tid++) {
350 hwid = of_read_number(cell, ac);
351 if (arch_match_cpu_phys_id(cpu, hwid)) {
362 * arch_find_n_match_cpu_physical_id - See if the given device node is
363 * for the cpu corresponding to logical cpu 'cpu'. Return true if so,
364 * else false. If 'thread' is non-NULL, the local thread number within the
365 * core is returned in it.
367 bool __weak arch_find_n_match_cpu_physical_id(struct device_node *cpun,
368 int cpu, unsigned int *thread)
370 /* Check for non-standard "ibm,ppc-interrupt-server#s" property
371 * for thread ids on PowerPC. If it doesn't exist fallback to
372 * standard "reg" property.
374 if (IS_ENABLED(CONFIG_PPC) &&
375 __of_find_n_match_cpu_property(cpun,
376 "ibm,ppc-interrupt-server#s",
380 if (__of_find_n_match_cpu_property(cpun, "reg", cpu, thread))
387 * of_get_cpu_node - Get device node associated with the given logical CPU
389 * @cpu: CPU number(logical index) for which device node is required
390 * @thread: if not NULL, local thread number within the physical core is
393 * The main purpose of this function is to retrieve the device node for the
394 * given logical CPU index. It should be used to initialize the of_node in
395 * cpu device. Once of_node in cpu device is populated, all the further
396 * references can use that instead.
398 * CPU logical to physical index mapping is architecture specific and is built
399 * before booting secondary cores. This function uses arch_match_cpu_phys_id
400 * which can be overridden by architecture specific implementation.
402 * Returns a node pointer for the logical cpu if found, else NULL.
404 struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
406 struct device_node *cpun;
408 for_each_node_by_type(cpun, "cpu") {
409 if (arch_find_n_match_cpu_physical_id(cpun, cpu, thread))
414 EXPORT_SYMBOL(of_get_cpu_node);
417 * __of_device_is_compatible() - Check if the node matches given constraints
418 * @device: pointer to node
419 * @compat: required compatible string, NULL or "" for any match
420 * @type: required device_type value, NULL or "" for any match
421 * @name: required node name, NULL or "" for any match
423 * Checks if the given @compat, @type and @name strings match the
424 * properties of the given @device. A constraints can be skipped by
425 * passing NULL or an empty string as the constraint.
427 * Returns 0 for no match, and a positive integer on match. The return
428 * value is a relative score with larger values indicating better
429 * matches. The score is weighted for the most specific compatible value
430 * to get the highest score. Matching type is next, followed by matching
431 * name. Practically speaking, this results in the following priority
434 * 1. specific compatible && type && name
435 * 2. specific compatible && type
436 * 3. specific compatible && name
437 * 4. specific compatible
438 * 5. general compatible && type && name
439 * 6. general compatible && type
440 * 7. general compatible && name
441 * 8. general compatible
446 static int __of_device_is_compatible(const struct device_node *device,
447 const char *compat, const char *type, const char *name)
449 struct property *prop;
451 int index = 0, score = 0;
453 /* Compatible match has highest priority */
454 if (compat && compat[0]) {
455 prop = __of_find_property(device, "compatible", NULL);
456 for (cp = of_prop_next_string(prop, NULL); cp;
457 cp = of_prop_next_string(prop, cp), index++) {
458 if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
459 score = INT_MAX/2 - (index << 2);
467 /* Matching type is better than matching name */
468 if (type && type[0]) {
469 if (!device->type || of_node_cmp(type, device->type))
474 /* Matching name is a bit better than not */
475 if (name && name[0]) {
476 if (!device->name || of_node_cmp(name, device->name))
484 /** Checks if the given "compat" string matches one of the strings in
485 * the device's "compatible" property
487 int of_device_is_compatible(const struct device_node *device,
493 raw_spin_lock_irqsave(&devtree_lock, flags);
494 res = __of_device_is_compatible(device, compat, NULL, NULL);
495 raw_spin_unlock_irqrestore(&devtree_lock, flags);
498 EXPORT_SYMBOL(of_device_is_compatible);
501 * of_machine_is_compatible - Test root of device tree for a given compatible value
502 * @compat: compatible string to look for in root node's compatible property.
504 * Returns a positive integer if the root node has the given value in its
505 * compatible property.
507 int of_machine_is_compatible(const char *compat)
509 struct device_node *root;
512 root = of_find_node_by_path("/");
514 rc = of_device_is_compatible(root, compat);
519 EXPORT_SYMBOL(of_machine_is_compatible);
522 * __of_device_is_available - check if a device is available for use
524 * @device: Node to check for availability, with locks already held
526 * Returns true if the status property is absent or set to "okay" or "ok",
529 static bool __of_device_is_available(const struct device_node *device)
537 status = __of_get_property(device, "status", &statlen);
542 if (!strcmp(status, "okay") || !strcmp(status, "ok"))
550 * of_device_is_available - check if a device is available for use
552 * @device: Node to check for availability
554 * Returns true if the status property is absent or set to "okay" or "ok",
557 bool of_device_is_available(const struct device_node *device)
562 raw_spin_lock_irqsave(&devtree_lock, flags);
563 res = __of_device_is_available(device);
564 raw_spin_unlock_irqrestore(&devtree_lock, flags);
568 EXPORT_SYMBOL(of_device_is_available);
571 * of_get_parent - Get a node's parent if any
572 * @node: Node to get parent
574 * Returns a node pointer with refcount incremented, use
575 * of_node_put() on it when done.
577 struct device_node *of_get_parent(const struct device_node *node)
579 struct device_node *np;
585 raw_spin_lock_irqsave(&devtree_lock, flags);
586 np = of_node_get(node->parent);
587 raw_spin_unlock_irqrestore(&devtree_lock, flags);
590 EXPORT_SYMBOL(of_get_parent);
593 * of_get_next_parent - Iterate to a node's parent
594 * @node: Node to get parent of
596 * This is like of_get_parent() except that it drops the
597 * refcount on the passed node, making it suitable for iterating
598 * through a node's parents.
600 * Returns a node pointer with refcount incremented, use
601 * of_node_put() on it when done.
603 struct device_node *of_get_next_parent(struct device_node *node)
605 struct device_node *parent;
611 raw_spin_lock_irqsave(&devtree_lock, flags);
612 parent = of_node_get(node->parent);
614 raw_spin_unlock_irqrestore(&devtree_lock, flags);
617 EXPORT_SYMBOL(of_get_next_parent);
619 static struct device_node *__of_get_next_child(const struct device_node *node,
620 struct device_node *prev)
622 struct device_node *next;
627 next = prev ? prev->sibling : node->child;
628 for (; next; next = next->sibling)
629 if (of_node_get(next))
634 #define __for_each_child_of_node(parent, child) \
635 for (child = __of_get_next_child(parent, NULL); child != NULL; \
636 child = __of_get_next_child(parent, child))
639 * of_get_next_child - Iterate a node childs
641 * @prev: previous child of the parent node, or NULL to get first
643 * Returns a node pointer with refcount incremented, use
644 * of_node_put() on it when done.
646 struct device_node *of_get_next_child(const struct device_node *node,
647 struct device_node *prev)
649 struct device_node *next;
652 raw_spin_lock_irqsave(&devtree_lock, flags);
653 next = __of_get_next_child(node, prev);
654 raw_spin_unlock_irqrestore(&devtree_lock, flags);
657 EXPORT_SYMBOL(of_get_next_child);
660 * of_get_next_available_child - Find the next available child node
662 * @prev: previous child of the parent node, or NULL to get first
664 * This function is like of_get_next_child(), except that it
665 * automatically skips any disabled nodes (i.e. status = "disabled").
667 struct device_node *of_get_next_available_child(const struct device_node *node,
668 struct device_node *prev)
670 struct device_node *next;
676 raw_spin_lock_irqsave(&devtree_lock, flags);
677 next = prev ? prev->sibling : node->child;
678 for (; next; next = next->sibling) {
679 if (!__of_device_is_available(next))
681 if (of_node_get(next))
685 raw_spin_unlock_irqrestore(&devtree_lock, flags);
688 EXPORT_SYMBOL(of_get_next_available_child);
691 * of_get_child_by_name - Find the child node by name for a given parent
693 * @name: child name to look for.
695 * This function looks for child node for given matching name
697 * Returns a node pointer if found, with refcount incremented, use
698 * of_node_put() on it when done.
699 * Returns NULL if node is not found.
701 struct device_node *of_get_child_by_name(const struct device_node *node,
704 struct device_node *child;
706 for_each_child_of_node(node, child)
707 if (child->name && (of_node_cmp(child->name, name) == 0))
711 EXPORT_SYMBOL(of_get_child_by_name);
713 static struct device_node *__of_find_node_by_path(struct device_node *parent,
716 struct device_node *child;
720 end = strchr(path, ':');
722 end = strchrnul(path, '/');
728 __for_each_child_of_node(parent, child) {
729 const char *name = strrchr(child->full_name, '/');
730 if (WARN(!name, "malformed device_node %s\n", child->full_name))
733 if (strncmp(path, name, len) == 0 && (strlen(name) == len))
740 * of_find_node_opts_by_path - Find a node matching a full OF path
741 * @path: Either the full path to match, or if the path does not
742 * start with '/', the name of a property of the /aliases
743 * node (an alias). In the case of an alias, the node
744 * matching the alias' value will be returned.
745 * @opts: Address of a pointer into which to store the start of
746 * an options string appended to the end of the path with
752 * foo/bar Valid alias + relative path
754 * Returns a node pointer with refcount incremented, use
755 * of_node_put() on it when done.
757 struct device_node *of_find_node_opts_by_path(const char *path, const char **opts)
759 struct device_node *np = NULL;
762 const char *separator = strchr(path, ':');
765 *opts = separator ? separator + 1 : NULL;
767 if (strcmp(path, "/") == 0)
768 return of_node_get(of_root);
770 /* The path could begin with an alias */
773 const char *p = separator;
776 p = strchrnul(path, '/');
779 /* of_aliases must not be NULL */
783 for_each_property_of_node(of_aliases, pp) {
784 if (strlen(pp->name) == len && !strncmp(pp->name, path, len)) {
785 np = of_find_node_by_path(pp->value);
794 /* Step down the tree matching path components */
795 raw_spin_lock_irqsave(&devtree_lock, flags);
797 np = of_node_get(of_root);
798 while (np && *path == '/') {
799 path++; /* Increment past '/' delimiter */
800 np = __of_find_node_by_path(np, path);
801 path = strchrnul(path, '/');
802 if (separator && separator < path)
805 raw_spin_unlock_irqrestore(&devtree_lock, flags);
808 EXPORT_SYMBOL(of_find_node_opts_by_path);
811 * of_find_node_by_name - Find a node by its "name" property
812 * @from: The node to start searching from or NULL, the node
813 * you pass will not be searched, only the next one
814 * will; typically, you pass what the previous call
815 * returned. of_node_put() will be called on it
816 * @name: The name string to match against
818 * Returns a node pointer with refcount incremented, use
819 * of_node_put() on it when done.
821 struct device_node *of_find_node_by_name(struct device_node *from,
824 struct device_node *np;
827 raw_spin_lock_irqsave(&devtree_lock, flags);
828 for_each_of_allnodes_from(from, np)
829 if (np->name && (of_node_cmp(np->name, name) == 0)
833 raw_spin_unlock_irqrestore(&devtree_lock, flags);
836 EXPORT_SYMBOL(of_find_node_by_name);
839 * of_find_node_by_type - Find a node by its "device_type" property
840 * @from: The node to start searching from, or NULL to start searching
841 * the entire device tree. The node you pass will not be
842 * searched, only the next one will; typically, you pass
843 * what the previous call returned. of_node_put() will be
844 * called on from for you.
845 * @type: The type string to match against
847 * Returns a node pointer with refcount incremented, use
848 * of_node_put() on it when done.
850 struct device_node *of_find_node_by_type(struct device_node *from,
853 struct device_node *np;
856 raw_spin_lock_irqsave(&devtree_lock, flags);
857 for_each_of_allnodes_from(from, np)
858 if (np->type && (of_node_cmp(np->type, type) == 0)
862 raw_spin_unlock_irqrestore(&devtree_lock, flags);
865 EXPORT_SYMBOL(of_find_node_by_type);
868 * of_find_compatible_node - Find a node based on type and one of the
869 * tokens in its "compatible" property
870 * @from: The node to start searching from or NULL, the node
871 * you pass will not be searched, only the next one
872 * will; typically, you pass what the previous call
873 * returned. of_node_put() will be called on it
874 * @type: The type string to match "device_type" or NULL to ignore
875 * @compatible: The string to match to one of the tokens in the device
878 * Returns a node pointer with refcount incremented, use
879 * of_node_put() on it when done.
881 struct device_node *of_find_compatible_node(struct device_node *from,
882 const char *type, const char *compatible)
884 struct device_node *np;
887 raw_spin_lock_irqsave(&devtree_lock, flags);
888 for_each_of_allnodes_from(from, np)
889 if (__of_device_is_compatible(np, compatible, type, NULL) &&
893 raw_spin_unlock_irqrestore(&devtree_lock, flags);
896 EXPORT_SYMBOL(of_find_compatible_node);
899 * of_find_node_with_property - Find a node which has a property with
901 * @from: The node to start searching from or NULL, the node
902 * you pass will not be searched, only the next one
903 * will; typically, you pass what the previous call
904 * returned. of_node_put() will be called on it
905 * @prop_name: The name of the property to look for.
907 * Returns a node pointer with refcount incremented, use
908 * of_node_put() on it when done.
910 struct device_node *of_find_node_with_property(struct device_node *from,
911 const char *prop_name)
913 struct device_node *np;
917 raw_spin_lock_irqsave(&devtree_lock, flags);
918 for_each_of_allnodes_from(from, np) {
919 for (pp = np->properties; pp; pp = pp->next) {
920 if (of_prop_cmp(pp->name, prop_name) == 0) {
928 raw_spin_unlock_irqrestore(&devtree_lock, flags);
931 EXPORT_SYMBOL(of_find_node_with_property);
934 const struct of_device_id *__of_match_node(const struct of_device_id *matches,
935 const struct device_node *node)
937 const struct of_device_id *best_match = NULL;
938 int score, best_score = 0;
943 for (; matches->name[0] || matches->type[0] || matches->compatible[0]; matches++) {
944 score = __of_device_is_compatible(node, matches->compatible,
945 matches->type, matches->name);
946 if (score > best_score) {
947 best_match = matches;
956 * of_match_node - Tell if a device_node has a matching of_match structure
957 * @matches: array of of device match structures to search in
958 * @node: the of device structure to match against
960 * Low level utility function used by device matching.
962 const struct of_device_id *of_match_node(const struct of_device_id *matches,
963 const struct device_node *node)
965 const struct of_device_id *match;
968 raw_spin_lock_irqsave(&devtree_lock, flags);
969 match = __of_match_node(matches, node);
970 raw_spin_unlock_irqrestore(&devtree_lock, flags);
973 EXPORT_SYMBOL(of_match_node);
976 * of_find_matching_node_and_match - Find a node based on an of_device_id
978 * @from: The node to start searching from or NULL, the node
979 * you pass will not be searched, only the next one
980 * will; typically, you pass what the previous call
981 * returned. of_node_put() will be called on it
982 * @matches: array of of device match structures to search in
983 * @match Updated to point at the matches entry which matched
985 * Returns a node pointer with refcount incremented, use
986 * of_node_put() on it when done.
988 struct device_node *of_find_matching_node_and_match(struct device_node *from,
989 const struct of_device_id *matches,
990 const struct of_device_id **match)
992 struct device_node *np;
993 const struct of_device_id *m;
999 raw_spin_lock_irqsave(&devtree_lock, flags);
1000 for_each_of_allnodes_from(from, np) {
1001 m = __of_match_node(matches, np);
1002 if (m && of_node_get(np)) {
1009 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1012 EXPORT_SYMBOL(of_find_matching_node_and_match);
1015 * of_modalias_node - Lookup appropriate modalias for a device node
1016 * @node: pointer to a device tree node
1017 * @modalias: Pointer to buffer that modalias value will be copied into
1018 * @len: Length of modalias value
1020 * Based on the value of the compatible property, this routine will attempt
1021 * to choose an appropriate modalias value for a particular device tree node.
1022 * It does this by stripping the manufacturer prefix (as delimited by a ',')
1023 * from the first entry in the compatible list property.
1025 * This routine returns 0 on success, <0 on failure.
1027 int of_modalias_node(struct device_node *node, char *modalias, int len)
1029 const char *compatible, *p;
1032 compatible = of_get_property(node, "compatible", &cplen);
1033 if (!compatible || strlen(compatible) > cplen)
1035 p = strchr(compatible, ',');
1036 strlcpy(modalias, p ? p + 1 : compatible, len);
1039 EXPORT_SYMBOL_GPL(of_modalias_node);
1042 * of_find_node_by_phandle - Find a node given a phandle
1043 * @handle: phandle of the node to find
1045 * Returns a node pointer with refcount incremented, use
1046 * of_node_put() on it when done.
1048 struct device_node *of_find_node_by_phandle(phandle handle)
1050 struct device_node *np;
1051 unsigned long flags;
1056 raw_spin_lock_irqsave(&devtree_lock, flags);
1057 for_each_of_allnodes(np)
1058 if (np->phandle == handle)
1061 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1064 EXPORT_SYMBOL(of_find_node_by_phandle);
1067 * of_property_count_elems_of_size - Count the number of elements in a property
1069 * @np: device node from which the property value is to be read.
1070 * @propname: name of the property to be searched.
1071 * @elem_size: size of the individual element
1073 * Search for a property in a device node and count the number of elements of
1074 * size elem_size in it. Returns number of elements on sucess, -EINVAL if the
1075 * property does not exist or its length does not match a multiple of elem_size
1076 * and -ENODATA if the property does not have a value.
1078 int of_property_count_elems_of_size(const struct device_node *np,
1079 const char *propname, int elem_size)
1081 struct property *prop = of_find_property(np, propname, NULL);
1088 if (prop->length % elem_size != 0) {
1089 pr_err("size of %s in node %s is not a multiple of %d\n",
1090 propname, np->full_name, elem_size);
1094 return prop->length / elem_size;
1096 EXPORT_SYMBOL_GPL(of_property_count_elems_of_size);
1099 * of_find_property_value_of_size
1101 * @np: device node from which the property value is to be read.
1102 * @propname: name of the property to be searched.
1103 * @len: requested length of property value
1105 * Search for a property in a device node and valid the requested size.
1106 * Returns the property value on success, -EINVAL if the property does not
1107 * exist, -ENODATA if property does not have a value, and -EOVERFLOW if the
1108 * property data isn't large enough.
1111 static void *of_find_property_value_of_size(const struct device_node *np,
1112 const char *propname, u32 len)
1114 struct property *prop = of_find_property(np, propname, NULL);
1117 return ERR_PTR(-EINVAL);
1119 return ERR_PTR(-ENODATA);
1120 if (len > prop->length)
1121 return ERR_PTR(-EOVERFLOW);
1127 * of_property_read_u32_index - Find and read a u32 from a multi-value property.
1129 * @np: device node from which the property value is to be read.
1130 * @propname: name of the property to be searched.
1131 * @index: index of the u32 in the list of values
1132 * @out_value: pointer to return value, modified only if no error.
1134 * Search for a property in a device node and read nth 32-bit value from
1135 * it. Returns 0 on success, -EINVAL if the property does not exist,
1136 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1137 * property data isn't large enough.
1139 * The out_value is modified only if a valid u32 value can be decoded.
1141 int of_property_read_u32_index(const struct device_node *np,
1142 const char *propname,
1143 u32 index, u32 *out_value)
1145 const u32 *val = of_find_property_value_of_size(np, propname,
1146 ((index + 1) * sizeof(*out_value)));
1149 return PTR_ERR(val);
1151 *out_value = be32_to_cpup(((__be32 *)val) + index);
1154 EXPORT_SYMBOL_GPL(of_property_read_u32_index);
1157 * of_property_read_u8_array - Find and read an array of u8 from a property.
1159 * @np: device node from which the property value is to be read.
1160 * @propname: name of the property to be searched.
1161 * @out_values: pointer to return value, modified only if return value is 0.
1162 * @sz: number of array elements to read
1164 * Search for a property in a device node and read 8-bit value(s) from
1165 * it. Returns 0 on success, -EINVAL if the property does not exist,
1166 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1167 * property data isn't large enough.
1169 * dts entry of array should be like:
1170 * property = /bits/ 8 <0x50 0x60 0x70>;
1172 * The out_values is modified only if a valid u8 value can be decoded.
1174 int of_property_read_u8_array(const struct device_node *np,
1175 const char *propname, u8 *out_values, size_t sz)
1177 const u8 *val = of_find_property_value_of_size(np, propname,
1178 (sz * sizeof(*out_values)));
1181 return PTR_ERR(val);
1184 *out_values++ = *val++;
1187 EXPORT_SYMBOL_GPL(of_property_read_u8_array);
1190 * of_property_read_u16_array - Find and read an array of u16 from a property.
1192 * @np: device node from which the property value is to be read.
1193 * @propname: name of the property to be searched.
1194 * @out_values: pointer to return value, modified only if return value is 0.
1195 * @sz: number of array elements to read
1197 * Search for a property in a device node and read 16-bit value(s) from
1198 * it. Returns 0 on success, -EINVAL if the property does not exist,
1199 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1200 * property data isn't large enough.
1202 * dts entry of array should be like:
1203 * property = /bits/ 16 <0x5000 0x6000 0x7000>;
1205 * The out_values is modified only if a valid u16 value can be decoded.
1207 int of_property_read_u16_array(const struct device_node *np,
1208 const char *propname, u16 *out_values, size_t sz)
1210 const __be16 *val = of_find_property_value_of_size(np, propname,
1211 (sz * sizeof(*out_values)));
1214 return PTR_ERR(val);
1217 *out_values++ = be16_to_cpup(val++);
1220 EXPORT_SYMBOL_GPL(of_property_read_u16_array);
1223 * of_property_read_u32_array - Find and read an array of 32 bit integers
1226 * @np: device node from which the property value is to be read.
1227 * @propname: name of the property to be searched.
1228 * @out_values: pointer to return value, modified only if return value is 0.
1229 * @sz: number of array elements to read
1231 * Search for a property in a device node and read 32-bit value(s) from
1232 * it. Returns 0 on success, -EINVAL if the property does not exist,
1233 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1234 * property data isn't large enough.
1236 * The out_values is modified only if a valid u32 value can be decoded.
1238 int of_property_read_u32_array(const struct device_node *np,
1239 const char *propname, u32 *out_values,
1242 const __be32 *val = of_find_property_value_of_size(np, propname,
1243 (sz * sizeof(*out_values)));
1246 return PTR_ERR(val);
1249 *out_values++ = be32_to_cpup(val++);
1252 EXPORT_SYMBOL_GPL(of_property_read_u32_array);
1255 * of_property_read_u64 - Find and read a 64 bit integer from a property
1256 * @np: device node from which the property value is to be read.
1257 * @propname: name of the property to be searched.
1258 * @out_value: pointer to return value, modified only if return value is 0.
1260 * Search for a property in a device node and read a 64-bit value from
1261 * it. Returns 0 on success, -EINVAL if the property does not exist,
1262 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1263 * property data isn't large enough.
1265 * The out_value is modified only if a valid u64 value can be decoded.
1267 int of_property_read_u64(const struct device_node *np, const char *propname,
1270 const __be32 *val = of_find_property_value_of_size(np, propname,
1271 sizeof(*out_value));
1274 return PTR_ERR(val);
1276 *out_value = of_read_number(val, 2);
1279 EXPORT_SYMBOL_GPL(of_property_read_u64);
1282 * of_property_read_u64_array - Find and read an array of 64 bit integers
1285 * @np: device node from which the property value is to be read.
1286 * @propname: name of the property to be searched.
1287 * @out_values: pointer to return value, modified only if return value is 0.
1288 * @sz: number of array elements to read
1290 * Search for a property in a device node and read 64-bit value(s) from
1291 * it. Returns 0 on success, -EINVAL if the property does not exist,
1292 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1293 * property data isn't large enough.
1295 * The out_values is modified only if a valid u64 value can be decoded.
1297 int of_property_read_u64_array(const struct device_node *np,
1298 const char *propname, u64 *out_values,
1301 const __be32 *val = of_find_property_value_of_size(np, propname,
1302 (sz * sizeof(*out_values)));
1305 return PTR_ERR(val);
1308 *out_values++ = of_read_number(val, 2);
1313 EXPORT_SYMBOL_GPL(of_property_read_u64_array);
1316 * of_property_read_string - Find and read a string from a property
1317 * @np: device node from which the property value is to be read.
1318 * @propname: name of the property to be searched.
1319 * @out_string: pointer to null terminated return string, modified only if
1320 * return value is 0.
1322 * Search for a property in a device tree node and retrieve a null
1323 * terminated string value (pointer to data, not a copy). Returns 0 on
1324 * success, -EINVAL if the property does not exist, -ENODATA if property
1325 * does not have a value, and -EILSEQ if the string is not null-terminated
1326 * within the length of the property data.
1328 * The out_string pointer is modified only if a valid string can be decoded.
1330 int of_property_read_string(struct device_node *np, const char *propname,
1331 const char **out_string)
1333 struct property *prop = of_find_property(np, propname, NULL);
1338 if (strnlen(prop->value, prop->length) >= prop->length)
1340 *out_string = prop->value;
1343 EXPORT_SYMBOL_GPL(of_property_read_string);
1346 * of_property_match_string() - Find string in a list and return index
1347 * @np: pointer to node containing string list property
1348 * @propname: string list property name
1349 * @string: pointer to string to search for in string list
1351 * This function searches a string list property and returns the index
1352 * of a specific string value.
1354 int of_property_match_string(struct device_node *np, const char *propname,
1357 struct property *prop = of_find_property(np, propname, NULL);
1360 const char *p, *end;
1368 end = p + prop->length;
1370 for (i = 0; p < end; i++, p += l) {
1371 l = strnlen(p, end - p) + 1;
1374 pr_debug("comparing %s with %s\n", string, p);
1375 if (strcmp(string, p) == 0)
1376 return i; /* Found it; return index */
1380 EXPORT_SYMBOL_GPL(of_property_match_string);
1383 * of_property_read_string_helper() - Utility helper for parsing string properties
1384 * @np: device node from which the property value is to be read.
1385 * @propname: name of the property to be searched.
1386 * @out_strs: output array of string pointers.
1387 * @sz: number of array elements to read.
1388 * @skip: Number of strings to skip over at beginning of list.
1390 * Don't call this function directly. It is a utility helper for the
1391 * of_property_read_string*() family of functions.
1393 int of_property_read_string_helper(struct device_node *np, const char *propname,
1394 const char **out_strs, size_t sz, int skip)
1396 struct property *prop = of_find_property(np, propname, NULL);
1398 const char *p, *end;
1405 end = p + prop->length;
1407 for (i = 0; p < end && (!out_strs || i < skip + sz); i++, p += l) {
1408 l = strnlen(p, end - p) + 1;
1411 if (out_strs && i >= skip)
1415 return i <= 0 ? -ENODATA : i;
1417 EXPORT_SYMBOL_GPL(of_property_read_string_helper);
1419 void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
1422 printk("%s %s", msg, of_node_full_name(args->np));
1423 for (i = 0; i < args->args_count; i++)
1424 printk(i ? ",%08x" : ":%08x", args->args[i]);
1428 static int __of_parse_phandle_with_args(const struct device_node *np,
1429 const char *list_name,
1430 const char *cells_name,
1431 int cell_count, int index,
1432 struct of_phandle_args *out_args)
1434 const __be32 *list, *list_end;
1435 int rc = 0, size, cur_index = 0;
1437 struct device_node *node = NULL;
1440 /* Retrieve the phandle list property */
1441 list = of_get_property(np, list_name, &size);
1444 list_end = list + size / sizeof(*list);
1446 /* Loop over the phandles until all the requested entry is found */
1447 while (list < list_end) {
1452 * If phandle is 0, then it is an empty entry with no
1453 * arguments. Skip forward to the next entry.
1455 phandle = be32_to_cpup(list++);
1458 * Find the provider node and parse the #*-cells
1459 * property to determine the argument length.
1461 * This is not needed if the cell count is hard-coded
1462 * (i.e. cells_name not set, but cell_count is set),
1463 * except when we're going to return the found node
1466 if (cells_name || cur_index == index) {
1467 node = of_find_node_by_phandle(phandle);
1469 pr_err("%s: could not find phandle\n",
1476 if (of_property_read_u32(node, cells_name,
1478 pr_err("%s: could not get %s for %s\n",
1479 np->full_name, cells_name,
1488 * Make sure that the arguments actually fit in the
1489 * remaining property data length
1491 if (list + count > list_end) {
1492 pr_err("%s: arguments longer than property\n",
1499 * All of the error cases above bail out of the loop, so at
1500 * this point, the parsing is successful. If the requested
1501 * index matches, then fill the out_args structure and return,
1502 * or return -ENOENT for an empty entry.
1505 if (cur_index == index) {
1511 if (WARN_ON(count > MAX_PHANDLE_ARGS))
1512 count = MAX_PHANDLE_ARGS;
1513 out_args->np = node;
1514 out_args->args_count = count;
1515 for (i = 0; i < count; i++)
1516 out_args->args[i] = be32_to_cpup(list++);
1521 /* Found it! return success */
1532 * Unlock node before returning result; will be one of:
1533 * -ENOENT : index is for empty phandle
1534 * -EINVAL : parsing error on data
1535 * [1..n] : Number of phandle (count mode; when index = -1)
1537 rc = index < 0 ? cur_index : -ENOENT;
1545 * of_parse_phandle - Resolve a phandle property to a device_node pointer
1546 * @np: Pointer to device node holding phandle property
1547 * @phandle_name: Name of property holding a phandle value
1548 * @index: For properties holding a table of phandles, this is the index into
1551 * Returns the device_node pointer with refcount incremented. Use
1552 * of_node_put() on it when done.
1554 struct device_node *of_parse_phandle(const struct device_node *np,
1555 const char *phandle_name, int index)
1557 struct of_phandle_args args;
1562 if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0,
1568 EXPORT_SYMBOL(of_parse_phandle);
1571 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
1572 * @np: pointer to a device tree node containing a list
1573 * @list_name: property name that contains a list
1574 * @cells_name: property name that specifies phandles' arguments count
1575 * @index: index of a phandle to parse out
1576 * @out_args: optional pointer to output arguments structure (will be filled)
1578 * This function is useful to parse lists of phandles and their arguments.
1579 * Returns 0 on success and fills out_args, on error returns appropriate
1582 * Caller is responsible to call of_node_put() on the returned out_args->np
1588 * #list-cells = <2>;
1592 * #list-cells = <1>;
1596 * list = <&phandle1 1 2 &phandle2 3>;
1599 * To get a device_node of the `node2' node you may call this:
1600 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
1602 int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
1603 const char *cells_name, int index,
1604 struct of_phandle_args *out_args)
1608 return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
1611 EXPORT_SYMBOL(of_parse_phandle_with_args);
1614 * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
1615 * @np: pointer to a device tree node containing a list
1616 * @list_name: property name that contains a list
1617 * @cell_count: number of argument cells following the phandle
1618 * @index: index of a phandle to parse out
1619 * @out_args: optional pointer to output arguments structure (will be filled)
1621 * This function is useful to parse lists of phandles and their arguments.
1622 * Returns 0 on success and fills out_args, on error returns appropriate
1625 * Caller is responsible to call of_node_put() on the returned out_args->np
1637 * list = <&phandle1 0 2 &phandle2 2 3>;
1640 * To get a device_node of the `node2' node you may call this:
1641 * of_parse_phandle_with_fixed_args(node3, "list", 2, 1, &args);
1643 int of_parse_phandle_with_fixed_args(const struct device_node *np,
1644 const char *list_name, int cell_count,
1645 int index, struct of_phandle_args *out_args)
1649 return __of_parse_phandle_with_args(np, list_name, NULL, cell_count,
1652 EXPORT_SYMBOL(of_parse_phandle_with_fixed_args);
1655 * of_count_phandle_with_args() - Find the number of phandles references in a property
1656 * @np: pointer to a device tree node containing a list
1657 * @list_name: property name that contains a list
1658 * @cells_name: property name that specifies phandles' arguments count
1660 * Returns the number of phandle + argument tuples within a property. It
1661 * is a typical pattern to encode a list of phandle and variable
1662 * arguments into a single property. The number of arguments is encoded
1663 * by a property in the phandle-target node. For example, a gpios
1664 * property would contain a list of GPIO specifies consisting of a
1665 * phandle and 1 or more arguments. The number of arguments are
1666 * determined by the #gpio-cells property in the node pointed to by the
1669 int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
1670 const char *cells_name)
1672 return __of_parse_phandle_with_args(np, list_name, cells_name, 0, -1,
1675 EXPORT_SYMBOL(of_count_phandle_with_args);
1678 * __of_add_property - Add a property to a node without lock operations
1680 int __of_add_property(struct device_node *np, struct property *prop)
1682 struct property **next;
1685 next = &np->properties;
1687 if (strcmp(prop->name, (*next)->name) == 0)
1688 /* duplicate ! don't insert it */
1691 next = &(*next)->next;
1699 * of_add_property - Add a property to a node
1701 int of_add_property(struct device_node *np, struct property *prop)
1703 unsigned long flags;
1706 mutex_lock(&of_mutex);
1708 raw_spin_lock_irqsave(&devtree_lock, flags);
1709 rc = __of_add_property(np, prop);
1710 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1713 __of_add_property_sysfs(np, prop);
1715 mutex_unlock(&of_mutex);
1718 of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop, NULL);
1723 int __of_remove_property(struct device_node *np, struct property *prop)
1725 struct property **next;
1727 for (next = &np->properties; *next; next = &(*next)->next) {
1734 /* found the node */
1736 prop->next = np->deadprops;
1737 np->deadprops = prop;
1742 void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
1744 if (!IS_ENABLED(CONFIG_SYSFS))
1747 /* at early boot, bail here and defer setup to of_init() */
1748 if (of_kset && of_node_is_attached(np))
1749 sysfs_remove_bin_file(&np->kobj, &prop->attr);
1753 * of_remove_property - Remove a property from a node.
1755 * Note that we don't actually remove it, since we have given out
1756 * who-knows-how-many pointers to the data using get-property.
1757 * Instead we just move the property to the "dead properties"
1758 * list, so it won't be found any more.
1760 int of_remove_property(struct device_node *np, struct property *prop)
1762 unsigned long flags;
1765 mutex_lock(&of_mutex);
1767 raw_spin_lock_irqsave(&devtree_lock, flags);
1768 rc = __of_remove_property(np, prop);
1769 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1772 __of_remove_property_sysfs(np, prop);
1774 mutex_unlock(&of_mutex);
1777 of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop, NULL);
1782 int __of_update_property(struct device_node *np, struct property *newprop,
1783 struct property **oldpropp)
1785 struct property **next, *oldprop;
1787 for (next = &np->properties; *next; next = &(*next)->next) {
1788 if (of_prop_cmp((*next)->name, newprop->name) == 0)
1791 *oldpropp = oldprop = *next;
1794 /* replace the node */
1795 newprop->next = oldprop->next;
1797 oldprop->next = np->deadprops;
1798 np->deadprops = oldprop;
1801 newprop->next = NULL;
1808 void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
1809 struct property *oldprop)
1811 if (!IS_ENABLED(CONFIG_SYSFS))
1814 /* At early boot, bail out and defer setup to of_init() */
1819 sysfs_remove_bin_file(&np->kobj, &oldprop->attr);
1820 __of_add_property_sysfs(np, newprop);
1824 * of_update_property - Update a property in a node, if the property does
1825 * not exist, add it.
1827 * Note that we don't actually remove it, since we have given out
1828 * who-knows-how-many pointers to the data using get-property.
1829 * Instead we just move the property to the "dead properties" list,
1830 * and add the new property to the property list
1832 int of_update_property(struct device_node *np, struct property *newprop)
1834 struct property *oldprop;
1835 unsigned long flags;
1841 mutex_lock(&of_mutex);
1843 raw_spin_lock_irqsave(&devtree_lock, flags);
1844 rc = __of_update_property(np, newprop, &oldprop);
1845 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1848 __of_update_property_sysfs(np, newprop, oldprop);
1850 mutex_unlock(&of_mutex);
1853 of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop, oldprop);
1858 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1859 int id, const char *stem, int stem_len)
1863 strncpy(ap->stem, stem, stem_len);
1864 ap->stem[stem_len] = 0;
1865 list_add_tail(&ap->link, &aliases_lookup);
1866 pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
1867 ap->alias, ap->stem, ap->id, of_node_full_name(np));
1871 * of_alias_scan - Scan all properties of the 'aliases' node
1873 * The function scans all the properties of the 'aliases' node and populates
1874 * the global lookup table with the properties. It returns the
1875 * number of alias properties found, or an error code in case of failure.
1877 * @dt_alloc: An allocator that provides a virtual address to memory
1878 * for storing the resulting tree
1880 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1882 struct property *pp;
1884 of_aliases = of_find_node_by_path("/aliases");
1885 of_chosen = of_find_node_by_path("/chosen");
1886 if (of_chosen == NULL)
1887 of_chosen = of_find_node_by_path("/chosen@0");
1890 /* linux,stdout-path and /aliases/stdout are for legacy compatibility */
1891 const char *name = of_get_property(of_chosen, "stdout-path", NULL);
1893 name = of_get_property(of_chosen, "linux,stdout-path", NULL);
1894 if (IS_ENABLED(CONFIG_PPC) && !name)
1895 name = of_get_property(of_aliases, "stdout", NULL);
1897 of_stdout = of_find_node_opts_by_path(name, &of_stdout_options);
1898 add_preferred_console("stdout-path", 0, NULL);
1905 for_each_property_of_node(of_aliases, pp) {
1906 const char *start = pp->name;
1907 const char *end = start + strlen(start);
1908 struct device_node *np;
1909 struct alias_prop *ap;
1912 /* Skip those we do not want to proceed */
1913 if (!strcmp(pp->name, "name") ||
1914 !strcmp(pp->name, "phandle") ||
1915 !strcmp(pp->name, "linux,phandle"))
1918 np = of_find_node_by_path(pp->value);
1922 /* walk the alias backwards to extract the id and work out
1923 * the 'stem' string */
1924 while (isdigit(*(end-1)) && end > start)
1928 if (kstrtoint(end, 10, &id) < 0)
1931 /* Allocate an alias_prop with enough space for the stem */
1932 ap = dt_alloc(sizeof(*ap) + len + 1, 4);
1935 memset(ap, 0, sizeof(*ap) + len + 1);
1937 of_alias_add(ap, np, id, start, len);
1942 * of_alias_get_id - Get alias id for the given device_node
1943 * @np: Pointer to the given device_node
1944 * @stem: Alias stem of the given device_node
1946 * The function travels the lookup table to get the alias id for the given
1947 * device_node and alias stem. It returns the alias id if found.
1949 int of_alias_get_id(struct device_node *np, const char *stem)
1951 struct alias_prop *app;
1954 mutex_lock(&of_mutex);
1955 list_for_each_entry(app, &aliases_lookup, link) {
1956 if (strcmp(app->stem, stem) != 0)
1959 if (np == app->np) {
1964 mutex_unlock(&of_mutex);
1968 EXPORT_SYMBOL_GPL(of_alias_get_id);
1970 const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
1973 const void *curv = cur;
1983 curv += sizeof(*cur);
1984 if (curv >= prop->value + prop->length)
1988 *pu = be32_to_cpup(curv);
1991 EXPORT_SYMBOL_GPL(of_prop_next_u32);
1993 const char *of_prop_next_string(struct property *prop, const char *cur)
1995 const void *curv = cur;
2003 curv += strlen(cur) + 1;
2004 if (curv >= prop->value + prop->length)
2009 EXPORT_SYMBOL_GPL(of_prop_next_string);
2012 * of_console_check() - Test and setup console for DT setup
2013 * @dn - Pointer to device node
2014 * @name - Name to use for preferred console without index. ex. "ttyS"
2015 * @index - Index to use for preferred console.
2017 * Check if the given device node matches the stdout-path property in the
2018 * /chosen node. If it does then register it as the preferred console and return
2019 * TRUE. Otherwise return FALSE.
2021 bool of_console_check(struct device_node *dn, char *name, int index)
2023 if (!dn || dn != of_stdout || console_set_on_cmdline)
2025 return !add_preferred_console(name, index,
2026 kstrdup(of_stdout_options, GFP_KERNEL));
2028 EXPORT_SYMBOL_GPL(of_console_check);
2031 * of_find_next_cache_node - Find a node's subsidiary cache
2032 * @np: node of type "cpu" or "cache"
2034 * Returns a node pointer with refcount incremented, use
2035 * of_node_put() on it when done. Caller should hold a reference
2038 struct device_node *of_find_next_cache_node(const struct device_node *np)
2040 struct device_node *child;
2041 const phandle *handle;
2043 handle = of_get_property(np, "l2-cache", NULL);
2045 handle = of_get_property(np, "next-level-cache", NULL);
2048 return of_find_node_by_phandle(be32_to_cpup(handle));
2050 /* OF on pmac has nodes instead of properties named "l2-cache"
2051 * beneath CPU nodes.
2053 if (!strcmp(np->type, "cpu"))
2054 for_each_child_of_node(np, child)
2055 if (!strcmp(child->type, "cache"))
2062 * of_graph_parse_endpoint() - parse common endpoint node properties
2063 * @node: pointer to endpoint device_node
2064 * @endpoint: pointer to the OF endpoint data structure
2066 * The caller should hold a reference to @node.
2068 int of_graph_parse_endpoint(const struct device_node *node,
2069 struct of_endpoint *endpoint)
2071 struct device_node *port_node = of_get_parent(node);
2073 WARN_ONCE(!port_node, "%s(): endpoint %s has no parent node\n",
2074 __func__, node->full_name);
2076 memset(endpoint, 0, sizeof(*endpoint));
2078 endpoint->local_node = node;
2080 * It doesn't matter whether the two calls below succeed.
2081 * If they don't then the default value 0 is used.
2083 of_property_read_u32(port_node, "reg", &endpoint->port);
2084 of_property_read_u32(node, "reg", &endpoint->id);
2086 of_node_put(port_node);
2090 EXPORT_SYMBOL(of_graph_parse_endpoint);
2093 * of_graph_get_next_endpoint() - get next endpoint node
2094 * @parent: pointer to the parent device node
2095 * @prev: previous endpoint node, or NULL to get first
2097 * Return: An 'endpoint' node pointer with refcount incremented. Refcount
2098 * of the passed @prev node is not decremented, the caller have to use
2099 * of_node_put() on it when done.
2101 struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
2102 struct device_node *prev)
2104 struct device_node *endpoint;
2105 struct device_node *port;
2111 * Start by locating the port node. If no previous endpoint is specified
2112 * search for the first port node, otherwise get the previous endpoint
2116 struct device_node *node;
2118 node = of_get_child_by_name(parent, "ports");
2122 port = of_get_child_by_name(parent, "port");
2126 pr_err("%s(): no port node found in %s\n",
2127 __func__, parent->full_name);
2131 port = of_get_parent(prev);
2132 if (WARN_ONCE(!port, "%s(): endpoint %s has no parent node\n",
2133 __func__, prev->full_name))
2137 * Avoid dropping prev node refcount to 0 when getting the next
2145 * Now that we have a port node, get the next endpoint by
2146 * getting the next child. If the previous endpoint is NULL this
2147 * will return the first child.
2149 endpoint = of_get_next_child(port, prev);
2155 /* No more endpoints under this port, try the next one. */
2159 port = of_get_next_child(parent, port);
2162 } while (of_node_cmp(port->name, "port"));
2165 EXPORT_SYMBOL(of_graph_get_next_endpoint);
2168 * of_graph_get_remote_port_parent() - get remote port's parent node
2169 * @node: pointer to a local endpoint device_node
2171 * Return: Remote device node associated with remote endpoint node linked
2172 * to @node. Use of_node_put() on it when done.
2174 struct device_node *of_graph_get_remote_port_parent(
2175 const struct device_node *node)
2177 struct device_node *np;
2180 /* Get remote endpoint node. */
2181 np = of_parse_phandle(node, "remote-endpoint", 0);
2183 /* Walk 3 levels up only if there is 'ports' node. */
2184 for (depth = 3; depth && np; depth--) {
2185 np = of_get_next_parent(np);
2186 if (depth == 2 && of_node_cmp(np->name, "ports"))
2191 EXPORT_SYMBOL(of_graph_get_remote_port_parent);
2194 * of_graph_get_remote_port() - get remote port node
2195 * @node: pointer to a local endpoint device_node
2197 * Return: Remote port node associated with remote endpoint node linked
2198 * to @node. Use of_node_put() on it when done.
2200 struct device_node *of_graph_get_remote_port(const struct device_node *node)
2202 struct device_node *np;
2204 /* Get remote endpoint node. */
2205 np = of_parse_phandle(node, "remote-endpoint", 0);
2208 return of_get_next_parent(np);
2210 EXPORT_SYMBOL(of_graph_get_remote_port);