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;
44 * Used to protect the of_aliases, to hold off addition of nodes to sysfs.
45 * This mutex must be held whenever modifications are being made to the
46 * device tree. The of_{attach,detach}_node() and
47 * of_{add,remove,update}_property() helpers make sure this happens.
49 DEFINE_MUTEX(of_mutex);
51 /* use when traversing tree through the child, sibling,
52 * or parent members of struct device_node.
54 DEFINE_RAW_SPINLOCK(devtree_lock);
56 int of_n_addr_cells(struct device_node *np)
63 ip = of_get_property(np, "#address-cells", NULL);
65 return be32_to_cpup(ip);
67 /* No #address-cells property for the root node */
68 return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
70 EXPORT_SYMBOL(of_n_addr_cells);
72 int of_n_size_cells(struct device_node *np)
79 ip = of_get_property(np, "#size-cells", NULL);
81 return be32_to_cpup(ip);
83 /* No #size-cells property for the root node */
84 return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
86 EXPORT_SYMBOL(of_n_size_cells);
89 int __weak of_node_to_nid(struct device_node *np)
91 return numa_node_id();
95 #ifndef CONFIG_OF_DYNAMIC
96 static void of_node_release(struct kobject *kobj)
98 /* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
100 #endif /* CONFIG_OF_DYNAMIC */
102 struct kobj_type of_node_ktype = {
103 .release = of_node_release,
106 static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
107 struct bin_attribute *bin_attr, char *buf,
108 loff_t offset, size_t count)
110 struct property *pp = container_of(bin_attr, struct property, attr);
111 return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
114 static const char *safe_name(struct kobject *kobj, const char *orig_name)
116 const char *name = orig_name;
117 struct kernfs_node *kn;
120 /* don't be a hero. After 16 tries give up */
121 while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {
123 if (name != orig_name)
125 name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
128 if (name != orig_name)
129 pr_warn("device-tree: Duplicate name in %s, renamed to \"%s\"\n",
130 kobject_name(kobj), name);
134 int __of_add_property_sysfs(struct device_node *np, struct property *pp)
138 /* Important: Don't leak passwords */
139 bool secure = strncmp(pp->name, "security-", 9) == 0;
141 if (!IS_ENABLED(CONFIG_SYSFS))
144 if (!of_kset || !of_node_is_attached(np))
147 sysfs_bin_attr_init(&pp->attr);
148 pp->attr.attr.name = safe_name(&np->kobj, pp->name);
149 pp->attr.attr.mode = secure ? S_IRUSR : S_IRUGO;
150 pp->attr.size = secure ? 0 : pp->length;
151 pp->attr.read = of_node_property_read;
153 rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
154 WARN(rc, "error adding attribute %s to node %s\n", pp->name, np->full_name);
158 int __of_attach_node_sysfs(struct device_node *np)
164 if (!IS_ENABLED(CONFIG_SYSFS))
170 np->kobj.kset = of_kset;
172 /* Nodes without parents are new top level trees */
173 rc = kobject_add(&np->kobj, NULL, "%s",
174 safe_name(&of_kset->kobj, "base"));
176 name = safe_name(&np->parent->kobj, kbasename(np->full_name));
177 if (!name || !name[0])
180 rc = kobject_add(&np->kobj, &np->parent->kobj, "%s", name);
185 for_each_property_of_node(np, pp)
186 __of_add_property_sysfs(np, pp);
191 static int __init of_init(void)
193 struct device_node *np;
195 /* Create the kset, and register existing nodes */
196 mutex_lock(&of_mutex);
197 of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj);
199 mutex_unlock(&of_mutex);
202 for_each_of_allnodes(np)
203 __of_attach_node_sysfs(np);
204 mutex_unlock(&of_mutex);
206 /* Symlink in /proc as required by userspace ABI */
208 proc_symlink("device-tree", NULL, "/sys/firmware/devicetree/base");
212 core_initcall(of_init);
214 static struct property *__of_find_property(const struct device_node *np,
215 const char *name, int *lenp)
222 for (pp = np->properties; pp; pp = pp->next) {
223 if (of_prop_cmp(pp->name, name) == 0) {
233 struct property *of_find_property(const struct device_node *np,
240 raw_spin_lock_irqsave(&devtree_lock, flags);
241 pp = __of_find_property(np, name, lenp);
242 raw_spin_unlock_irqrestore(&devtree_lock, flags);
246 EXPORT_SYMBOL(of_find_property);
248 struct device_node *__of_find_all_nodes(struct device_node *prev)
250 struct device_node *np;
253 } else if (prev->child) {
256 /* Walk back up looking for a sibling, or the end of the structure */
258 while (np->parent && !np->sibling)
260 np = np->sibling; /* Might be null at the end of the tree */
266 * of_find_all_nodes - Get next node in global list
267 * @prev: Previous node or NULL to start iteration
268 * of_node_put() will be called on it
270 * Returns a node pointer with refcount incremented, use
271 * of_node_put() on it when done.
273 struct device_node *of_find_all_nodes(struct device_node *prev)
275 struct device_node *np;
278 raw_spin_lock_irqsave(&devtree_lock, flags);
279 np = __of_find_all_nodes(prev);
282 raw_spin_unlock_irqrestore(&devtree_lock, flags);
285 EXPORT_SYMBOL(of_find_all_nodes);
288 * Find a property with a given name for a given node
289 * and return the value.
291 const void *__of_get_property(const struct device_node *np,
292 const char *name, int *lenp)
294 struct property *pp = __of_find_property(np, name, lenp);
296 return pp ? pp->value : NULL;
300 * Find a property with a given name for a given node
301 * and return the value.
303 const void *of_get_property(const struct device_node *np, const char *name,
306 struct property *pp = of_find_property(np, name, lenp);
308 return pp ? pp->value : NULL;
310 EXPORT_SYMBOL(of_get_property);
313 * arch_match_cpu_phys_id - Match the given logical CPU and physical id
315 * @cpu: logical cpu index of a core/thread
316 * @phys_id: physical identifier of a core/thread
318 * CPU logical to physical index mapping is architecture specific.
319 * However this __weak function provides a default match of physical
320 * id to logical cpu index. phys_id provided here is usually values read
321 * from the device tree which must match the hardware internal registers.
323 * Returns true if the physical identifier and the logical cpu index
324 * correspond to the same core/thread, false otherwise.
326 bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id)
328 return (u32)phys_id == cpu;
332 * Checks if the given "prop_name" property holds the physical id of the
333 * core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not
334 * NULL, local thread number within the core is returned in it.
336 static bool __of_find_n_match_cpu_property(struct device_node *cpun,
337 const char *prop_name, int cpu, unsigned int *thread)
340 int ac, prop_len, tid;
343 ac = of_n_addr_cells(cpun);
344 cell = of_get_property(cpun, prop_name, &prop_len);
347 prop_len /= sizeof(*cell) * ac;
348 for (tid = 0; tid < prop_len; tid++) {
349 hwid = of_read_number(cell, ac);
350 if (arch_match_cpu_phys_id(cpu, hwid)) {
361 * arch_find_n_match_cpu_physical_id - See if the given device node is
362 * for the cpu corresponding to logical cpu 'cpu'. Return true if so,
363 * else false. If 'thread' is non-NULL, the local thread number within the
364 * core is returned in it.
366 bool __weak arch_find_n_match_cpu_physical_id(struct device_node *cpun,
367 int cpu, unsigned int *thread)
369 /* Check for non-standard "ibm,ppc-interrupt-server#s" property
370 * for thread ids on PowerPC. If it doesn't exist fallback to
371 * standard "reg" property.
373 if (IS_ENABLED(CONFIG_PPC) &&
374 __of_find_n_match_cpu_property(cpun,
375 "ibm,ppc-interrupt-server#s",
379 if (__of_find_n_match_cpu_property(cpun, "reg", cpu, thread))
386 * of_get_cpu_node - Get device node associated with the given logical CPU
388 * @cpu: CPU number(logical index) for which device node is required
389 * @thread: if not NULL, local thread number within the physical core is
392 * The main purpose of this function is to retrieve the device node for the
393 * given logical CPU index. It should be used to initialize the of_node in
394 * cpu device. Once of_node in cpu device is populated, all the further
395 * references can use that instead.
397 * CPU logical to physical index mapping is architecture specific and is built
398 * before booting secondary cores. This function uses arch_match_cpu_phys_id
399 * which can be overridden by architecture specific implementation.
401 * Returns a node pointer for the logical cpu if found, else NULL.
403 struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
405 struct device_node *cpun;
407 for_each_node_by_type(cpun, "cpu") {
408 if (arch_find_n_match_cpu_physical_id(cpun, cpu, thread))
413 EXPORT_SYMBOL(of_get_cpu_node);
416 * __of_device_is_compatible() - Check if the node matches given constraints
417 * @device: pointer to node
418 * @compat: required compatible string, NULL or "" for any match
419 * @type: required device_type value, NULL or "" for any match
420 * @name: required node name, NULL or "" for any match
422 * Checks if the given @compat, @type and @name strings match the
423 * properties of the given @device. A constraints can be skipped by
424 * passing NULL or an empty string as the constraint.
426 * Returns 0 for no match, and a positive integer on match. The return
427 * value is a relative score with larger values indicating better
428 * matches. The score is weighted for the most specific compatible value
429 * to get the highest score. Matching type is next, followed by matching
430 * name. Practically speaking, this results in the following priority
433 * 1. specific compatible && type && name
434 * 2. specific compatible && type
435 * 3. specific compatible && name
436 * 4. specific compatible
437 * 5. general compatible && type && name
438 * 6. general compatible && type
439 * 7. general compatible && name
440 * 8. general compatible
445 static int __of_device_is_compatible(const struct device_node *device,
446 const char *compat, const char *type, const char *name)
448 struct property *prop;
450 int index = 0, score = 0;
452 /* Compatible match has highest priority */
453 if (compat && compat[0]) {
454 prop = __of_find_property(device, "compatible", NULL);
455 for (cp = of_prop_next_string(prop, NULL); cp;
456 cp = of_prop_next_string(prop, cp), index++) {
457 if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
458 score = INT_MAX/2 - (index << 2);
466 /* Matching type is better than matching name */
467 if (type && type[0]) {
468 if (!device->type || of_node_cmp(type, device->type))
473 /* Matching name is a bit better than not */
474 if (name && name[0]) {
475 if (!device->name || of_node_cmp(name, device->name))
483 /** Checks if the given "compat" string matches one of the strings in
484 * the device's "compatible" property
486 int of_device_is_compatible(const struct device_node *device,
492 raw_spin_lock_irqsave(&devtree_lock, flags);
493 res = __of_device_is_compatible(device, compat, NULL, NULL);
494 raw_spin_unlock_irqrestore(&devtree_lock, flags);
497 EXPORT_SYMBOL(of_device_is_compatible);
500 * of_machine_is_compatible - Test root of device tree for a given compatible value
501 * @compat: compatible string to look for in root node's compatible property.
503 * Returns a positive integer if the root node has the given value in its
504 * compatible property.
506 int of_machine_is_compatible(const char *compat)
508 struct device_node *root;
511 root = of_find_node_by_path("/");
513 rc = of_device_is_compatible(root, compat);
518 EXPORT_SYMBOL(of_machine_is_compatible);
521 * __of_device_is_available - check if a device is available for use
523 * @device: Node to check for availability, with locks already held
525 * Returns true if the status property is absent or set to "okay" or "ok",
528 static bool __of_device_is_available(const struct device_node *device)
536 status = __of_get_property(device, "status", &statlen);
541 if (!strcmp(status, "okay") || !strcmp(status, "ok"))
549 * of_device_is_available - check if a device is available for use
551 * @device: Node to check for availability
553 * Returns true if the status property is absent or set to "okay" or "ok",
556 bool of_device_is_available(const struct device_node *device)
561 raw_spin_lock_irqsave(&devtree_lock, flags);
562 res = __of_device_is_available(device);
563 raw_spin_unlock_irqrestore(&devtree_lock, flags);
567 EXPORT_SYMBOL(of_device_is_available);
570 * of_get_parent - Get a node's parent if any
571 * @node: Node to get parent
573 * Returns a node pointer with refcount incremented, use
574 * of_node_put() on it when done.
576 struct device_node *of_get_parent(const struct device_node *node)
578 struct device_node *np;
584 raw_spin_lock_irqsave(&devtree_lock, flags);
585 np = of_node_get(node->parent);
586 raw_spin_unlock_irqrestore(&devtree_lock, flags);
589 EXPORT_SYMBOL(of_get_parent);
592 * of_get_next_parent - Iterate to a node's parent
593 * @node: Node to get parent of
595 * This is like of_get_parent() except that it drops the
596 * refcount on the passed node, making it suitable for iterating
597 * through a node's parents.
599 * Returns a node pointer with refcount incremented, use
600 * of_node_put() on it when done.
602 struct device_node *of_get_next_parent(struct device_node *node)
604 struct device_node *parent;
610 raw_spin_lock_irqsave(&devtree_lock, flags);
611 parent = of_node_get(node->parent);
613 raw_spin_unlock_irqrestore(&devtree_lock, flags);
616 EXPORT_SYMBOL(of_get_next_parent);
618 static struct device_node *__of_get_next_child(const struct device_node *node,
619 struct device_node *prev)
621 struct device_node *next;
626 next = prev ? prev->sibling : node->child;
627 for (; next; next = next->sibling)
628 if (of_node_get(next))
633 #define __for_each_child_of_node(parent, child) \
634 for (child = __of_get_next_child(parent, NULL); child != NULL; \
635 child = __of_get_next_child(parent, child))
638 * of_get_next_child - Iterate a node childs
640 * @prev: previous child of the parent node, or NULL to get first
642 * Returns a node pointer with refcount incremented, use
643 * of_node_put() on it when done.
645 struct device_node *of_get_next_child(const struct device_node *node,
646 struct device_node *prev)
648 struct device_node *next;
651 raw_spin_lock_irqsave(&devtree_lock, flags);
652 next = __of_get_next_child(node, prev);
653 raw_spin_unlock_irqrestore(&devtree_lock, flags);
656 EXPORT_SYMBOL(of_get_next_child);
659 * of_get_next_available_child - Find the next available child node
661 * @prev: previous child of the parent node, or NULL to get first
663 * This function is like of_get_next_child(), except that it
664 * automatically skips any disabled nodes (i.e. status = "disabled").
666 struct device_node *of_get_next_available_child(const struct device_node *node,
667 struct device_node *prev)
669 struct device_node *next;
675 raw_spin_lock_irqsave(&devtree_lock, flags);
676 next = prev ? prev->sibling : node->child;
677 for (; next; next = next->sibling) {
678 if (!__of_device_is_available(next))
680 if (of_node_get(next))
684 raw_spin_unlock_irqrestore(&devtree_lock, flags);
687 EXPORT_SYMBOL(of_get_next_available_child);
690 * of_get_child_by_name - Find the child node by name for a given parent
692 * @name: child name to look for.
694 * This function looks for child node for given matching name
696 * Returns a node pointer if found, with refcount incremented, use
697 * of_node_put() on it when done.
698 * Returns NULL if node is not found.
700 struct device_node *of_get_child_by_name(const struct device_node *node,
703 struct device_node *child;
705 for_each_child_of_node(node, child)
706 if (child->name && (of_node_cmp(child->name, name) == 0))
710 EXPORT_SYMBOL(of_get_child_by_name);
712 static struct device_node *__of_find_node_by_path(struct device_node *parent,
715 struct device_node *child;
716 int len = strchrnul(path, '/') - path;
722 term = strchrnul(path, ':') - path;
726 __for_each_child_of_node(parent, child) {
727 const char *name = strrchr(child->full_name, '/');
728 if (WARN(!name, "malformed device_node %s\n", child->full_name))
731 if (strncmp(path, name, len) == 0 && (strlen(name) == len))
738 * of_find_node_opts_by_path - Find a node matching a full OF path
739 * @path: Either the full path to match, or if the path does not
740 * start with '/', the name of a property of the /aliases
741 * node (an alias). In the case of an alias, the node
742 * matching the alias' value will be returned.
743 * @opts: Address of a pointer into which to store the start of
744 * an options string appended to the end of the path with
750 * foo/bar Valid alias + relative path
752 * Returns a node pointer with refcount incremented, use
753 * of_node_put() on it when done.
755 struct device_node *of_find_node_opts_by_path(const char *path, const char **opts)
757 struct device_node *np = NULL;
760 const char *separator = strchr(path, ':');
763 *opts = separator ? separator + 1 : NULL;
765 if (strcmp(path, "/") == 0)
766 return of_node_get(of_root);
768 /* The path could begin with an alias */
770 char *p = strchrnul(path, '/');
771 int len = separator ? separator - path : p - path;
773 /* of_aliases must not be NULL */
777 for_each_property_of_node(of_aliases, pp) {
778 if (strlen(pp->name) == len && !strncmp(pp->name, path, len)) {
779 np = of_find_node_by_path(pp->value);
788 /* Step down the tree matching path components */
789 raw_spin_lock_irqsave(&devtree_lock, flags);
791 np = of_node_get(of_root);
792 while (np && *path == '/') {
793 path++; /* Increment past '/' delimiter */
794 np = __of_find_node_by_path(np, path);
795 path = strchrnul(path, '/');
797 raw_spin_unlock_irqrestore(&devtree_lock, flags);
800 EXPORT_SYMBOL(of_find_node_opts_by_path);
803 * of_find_node_by_name - Find a node by its "name" property
804 * @from: The node to start searching from or NULL, the node
805 * you pass will not be searched, only the next one
806 * will; typically, you pass what the previous call
807 * returned. of_node_put() will be called on it
808 * @name: The name string to match against
810 * Returns a node pointer with refcount incremented, use
811 * of_node_put() on it when done.
813 struct device_node *of_find_node_by_name(struct device_node *from,
816 struct device_node *np;
819 raw_spin_lock_irqsave(&devtree_lock, flags);
820 for_each_of_allnodes_from(from, np)
821 if (np->name && (of_node_cmp(np->name, name) == 0)
825 raw_spin_unlock_irqrestore(&devtree_lock, flags);
828 EXPORT_SYMBOL(of_find_node_by_name);
831 * of_find_node_by_type - Find a node by its "device_type" property
832 * @from: The node to start searching from, or NULL to start searching
833 * the entire device tree. The node you pass will not be
834 * searched, only the next one will; typically, you pass
835 * what the previous call returned. of_node_put() will be
836 * called on from for you.
837 * @type: The type string to match against
839 * Returns a node pointer with refcount incremented, use
840 * of_node_put() on it when done.
842 struct device_node *of_find_node_by_type(struct device_node *from,
845 struct device_node *np;
848 raw_spin_lock_irqsave(&devtree_lock, flags);
849 for_each_of_allnodes_from(from, np)
850 if (np->type && (of_node_cmp(np->type, type) == 0)
854 raw_spin_unlock_irqrestore(&devtree_lock, flags);
857 EXPORT_SYMBOL(of_find_node_by_type);
860 * of_find_compatible_node - Find a node based on type and one of the
861 * tokens in its "compatible" property
862 * @from: The node to start searching from or NULL, the node
863 * you pass will not be searched, only the next one
864 * will; typically, you pass what the previous call
865 * returned. of_node_put() will be called on it
866 * @type: The type string to match "device_type" or NULL to ignore
867 * @compatible: The string to match to one of the tokens in the device
870 * Returns a node pointer with refcount incremented, use
871 * of_node_put() on it when done.
873 struct device_node *of_find_compatible_node(struct device_node *from,
874 const char *type, const char *compatible)
876 struct device_node *np;
879 raw_spin_lock_irqsave(&devtree_lock, flags);
880 for_each_of_allnodes_from(from, np)
881 if (__of_device_is_compatible(np, compatible, type, NULL) &&
885 raw_spin_unlock_irqrestore(&devtree_lock, flags);
888 EXPORT_SYMBOL(of_find_compatible_node);
891 * of_find_node_with_property - Find a node which has a property with
893 * @from: The node to start searching from or NULL, the node
894 * you pass will not be searched, only the next one
895 * will; typically, you pass what the previous call
896 * returned. of_node_put() will be called on it
897 * @prop_name: The name of the property to look for.
899 * Returns a node pointer with refcount incremented, use
900 * of_node_put() on it when done.
902 struct device_node *of_find_node_with_property(struct device_node *from,
903 const char *prop_name)
905 struct device_node *np;
909 raw_spin_lock_irqsave(&devtree_lock, flags);
910 for_each_of_allnodes_from(from, np) {
911 for (pp = np->properties; pp; pp = pp->next) {
912 if (of_prop_cmp(pp->name, prop_name) == 0) {
920 raw_spin_unlock_irqrestore(&devtree_lock, flags);
923 EXPORT_SYMBOL(of_find_node_with_property);
926 const struct of_device_id *__of_match_node(const struct of_device_id *matches,
927 const struct device_node *node)
929 const struct of_device_id *best_match = NULL;
930 int score, best_score = 0;
935 for (; matches->name[0] || matches->type[0] || matches->compatible[0]; matches++) {
936 score = __of_device_is_compatible(node, matches->compatible,
937 matches->type, matches->name);
938 if (score > best_score) {
939 best_match = matches;
948 * of_match_node - Tell if a device_node has a matching of_match structure
949 * @matches: array of of device match structures to search in
950 * @node: the of device structure to match against
952 * Low level utility function used by device matching.
954 const struct of_device_id *of_match_node(const struct of_device_id *matches,
955 const struct device_node *node)
957 const struct of_device_id *match;
960 raw_spin_lock_irqsave(&devtree_lock, flags);
961 match = __of_match_node(matches, node);
962 raw_spin_unlock_irqrestore(&devtree_lock, flags);
965 EXPORT_SYMBOL(of_match_node);
968 * of_find_matching_node_and_match - Find a node based on an of_device_id
970 * @from: The node to start searching from or NULL, the node
971 * you pass will not be searched, only the next one
972 * will; typically, you pass what the previous call
973 * returned. of_node_put() will be called on it
974 * @matches: array of of device match structures to search in
975 * @match Updated to point at the matches entry which matched
977 * Returns a node pointer with refcount incremented, use
978 * of_node_put() on it when done.
980 struct device_node *of_find_matching_node_and_match(struct device_node *from,
981 const struct of_device_id *matches,
982 const struct of_device_id **match)
984 struct device_node *np;
985 const struct of_device_id *m;
991 raw_spin_lock_irqsave(&devtree_lock, flags);
992 for_each_of_allnodes_from(from, np) {
993 m = __of_match_node(matches, np);
994 if (m && of_node_get(np)) {
1001 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1004 EXPORT_SYMBOL(of_find_matching_node_and_match);
1007 * of_modalias_node - Lookup appropriate modalias for a device node
1008 * @node: pointer to a device tree node
1009 * @modalias: Pointer to buffer that modalias value will be copied into
1010 * @len: Length of modalias value
1012 * Based on the value of the compatible property, this routine will attempt
1013 * to choose an appropriate modalias value for a particular device tree node.
1014 * It does this by stripping the manufacturer prefix (as delimited by a ',')
1015 * from the first entry in the compatible list property.
1017 * This routine returns 0 on success, <0 on failure.
1019 int of_modalias_node(struct device_node *node, char *modalias, int len)
1021 const char *compatible, *p;
1024 compatible = of_get_property(node, "compatible", &cplen);
1025 if (!compatible || strlen(compatible) > cplen)
1027 p = strchr(compatible, ',');
1028 strlcpy(modalias, p ? p + 1 : compatible, len);
1031 EXPORT_SYMBOL_GPL(of_modalias_node);
1034 * of_find_node_by_phandle - Find a node given a phandle
1035 * @handle: phandle of the node to find
1037 * Returns a node pointer with refcount incremented, use
1038 * of_node_put() on it when done.
1040 struct device_node *of_find_node_by_phandle(phandle handle)
1042 struct device_node *np;
1043 unsigned long flags;
1048 raw_spin_lock_irqsave(&devtree_lock, flags);
1049 for_each_of_allnodes(np)
1050 if (np->phandle == handle)
1053 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1056 EXPORT_SYMBOL(of_find_node_by_phandle);
1059 * of_property_count_elems_of_size - Count the number of elements in a property
1061 * @np: device node from which the property value is to be read.
1062 * @propname: name of the property to be searched.
1063 * @elem_size: size of the individual element
1065 * Search for a property in a device node and count the number of elements of
1066 * size elem_size in it. Returns number of elements on sucess, -EINVAL if the
1067 * property does not exist or its length does not match a multiple of elem_size
1068 * and -ENODATA if the property does not have a value.
1070 int of_property_count_elems_of_size(const struct device_node *np,
1071 const char *propname, int elem_size)
1073 struct property *prop = of_find_property(np, propname, NULL);
1080 if (prop->length % elem_size != 0) {
1081 pr_err("size of %s in node %s is not a multiple of %d\n",
1082 propname, np->full_name, elem_size);
1086 return prop->length / elem_size;
1088 EXPORT_SYMBOL_GPL(of_property_count_elems_of_size);
1091 * of_find_property_value_of_size
1093 * @np: device node from which the property value is to be read.
1094 * @propname: name of the property to be searched.
1095 * @len: requested length of property value
1097 * Search for a property in a device node and valid the requested size.
1098 * Returns the property value on success, -EINVAL if the property does not
1099 * exist, -ENODATA if property does not have a value, and -EOVERFLOW if the
1100 * property data isn't large enough.
1103 static void *of_find_property_value_of_size(const struct device_node *np,
1104 const char *propname, u32 len)
1106 struct property *prop = of_find_property(np, propname, NULL);
1109 return ERR_PTR(-EINVAL);
1111 return ERR_PTR(-ENODATA);
1112 if (len > prop->length)
1113 return ERR_PTR(-EOVERFLOW);
1119 * of_property_read_u32_index - Find and read a u32 from a multi-value property.
1121 * @np: device node from which the property value is to be read.
1122 * @propname: name of the property to be searched.
1123 * @index: index of the u32 in the list of values
1124 * @out_value: pointer to return value, modified only if no error.
1126 * Search for a property in a device node and read nth 32-bit value from
1127 * it. Returns 0 on success, -EINVAL if the property does not exist,
1128 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1129 * property data isn't large enough.
1131 * The out_value is modified only if a valid u32 value can be decoded.
1133 int of_property_read_u32_index(const struct device_node *np,
1134 const char *propname,
1135 u32 index, u32 *out_value)
1137 const u32 *val = of_find_property_value_of_size(np, propname,
1138 ((index + 1) * sizeof(*out_value)));
1141 return PTR_ERR(val);
1143 *out_value = be32_to_cpup(((__be32 *)val) + index);
1146 EXPORT_SYMBOL_GPL(of_property_read_u32_index);
1149 * of_property_read_u8_array - Find and read an array of u8 from a property.
1151 * @np: device node from which the property value is to be read.
1152 * @propname: name of the property to be searched.
1153 * @out_values: pointer to return value, modified only if return value is 0.
1154 * @sz: number of array elements to read
1156 * Search for a property in a device node and read 8-bit value(s) from
1157 * it. Returns 0 on success, -EINVAL if the property does not exist,
1158 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1159 * property data isn't large enough.
1161 * dts entry of array should be like:
1162 * property = /bits/ 8 <0x50 0x60 0x70>;
1164 * The out_values is modified only if a valid u8 value can be decoded.
1166 int of_property_read_u8_array(const struct device_node *np,
1167 const char *propname, u8 *out_values, size_t sz)
1169 const u8 *val = of_find_property_value_of_size(np, propname,
1170 (sz * sizeof(*out_values)));
1173 return PTR_ERR(val);
1176 *out_values++ = *val++;
1179 EXPORT_SYMBOL_GPL(of_property_read_u8_array);
1182 * of_property_read_u16_array - Find and read an array of u16 from a property.
1184 * @np: device node from which the property value is to be read.
1185 * @propname: name of the property to be searched.
1186 * @out_values: pointer to return value, modified only if return value is 0.
1187 * @sz: number of array elements to read
1189 * Search for a property in a device node and read 16-bit value(s) from
1190 * it. Returns 0 on success, -EINVAL if the property does not exist,
1191 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1192 * property data isn't large enough.
1194 * dts entry of array should be like:
1195 * property = /bits/ 16 <0x5000 0x6000 0x7000>;
1197 * The out_values is modified only if a valid u16 value can be decoded.
1199 int of_property_read_u16_array(const struct device_node *np,
1200 const char *propname, u16 *out_values, size_t sz)
1202 const __be16 *val = of_find_property_value_of_size(np, propname,
1203 (sz * sizeof(*out_values)));
1206 return PTR_ERR(val);
1209 *out_values++ = be16_to_cpup(val++);
1212 EXPORT_SYMBOL_GPL(of_property_read_u16_array);
1215 * of_property_read_u32_array - Find and read an array of 32 bit integers
1218 * @np: device node from which the property value is to be read.
1219 * @propname: name of the property to be searched.
1220 * @out_values: pointer to return value, modified only if return value is 0.
1221 * @sz: number of array elements to read
1223 * Search for a property in a device node and read 32-bit value(s) from
1224 * it. Returns 0 on success, -EINVAL if the property does not exist,
1225 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1226 * property data isn't large enough.
1228 * The out_values is modified only if a valid u32 value can be decoded.
1230 int of_property_read_u32_array(const struct device_node *np,
1231 const char *propname, u32 *out_values,
1234 const __be32 *val = of_find_property_value_of_size(np, propname,
1235 (sz * sizeof(*out_values)));
1238 return PTR_ERR(val);
1241 *out_values++ = be32_to_cpup(val++);
1244 EXPORT_SYMBOL_GPL(of_property_read_u32_array);
1247 * of_property_read_u64 - Find and read a 64 bit integer from a property
1248 * @np: device node from which the property value is to be read.
1249 * @propname: name of the property to be searched.
1250 * @out_value: pointer to return value, modified only if return value is 0.
1252 * Search for a property in a device node and read a 64-bit value from
1253 * it. Returns 0 on success, -EINVAL if the property does not exist,
1254 * -ENODATA if property does not have a value, and -EOVERFLOW if the
1255 * property data isn't large enough.
1257 * The out_value is modified only if a valid u64 value can be decoded.
1259 int of_property_read_u64(const struct device_node *np, const char *propname,
1262 const __be32 *val = of_find_property_value_of_size(np, propname,
1263 sizeof(*out_value));
1266 return PTR_ERR(val);
1268 *out_value = of_read_number(val, 2);
1271 EXPORT_SYMBOL_GPL(of_property_read_u64);
1274 * of_property_read_string - Find and read a string from a property
1275 * @np: device node from which the property value is to be read.
1276 * @propname: name of the property to be searched.
1277 * @out_string: pointer to null terminated return string, modified only if
1278 * return value is 0.
1280 * Search for a property in a device tree node and retrieve a null
1281 * terminated string value (pointer to data, not a copy). Returns 0 on
1282 * success, -EINVAL if the property does not exist, -ENODATA if property
1283 * does not have a value, and -EILSEQ if the string is not null-terminated
1284 * within the length of the property data.
1286 * The out_string pointer is modified only if a valid string can be decoded.
1288 int of_property_read_string(struct device_node *np, const char *propname,
1289 const char **out_string)
1291 struct property *prop = of_find_property(np, propname, NULL);
1296 if (strnlen(prop->value, prop->length) >= prop->length)
1298 *out_string = prop->value;
1301 EXPORT_SYMBOL_GPL(of_property_read_string);
1304 * of_property_match_string() - Find string in a list and return index
1305 * @np: pointer to node containing string list property
1306 * @propname: string list property name
1307 * @string: pointer to string to search for in string list
1309 * This function searches a string list property and returns the index
1310 * of a specific string value.
1312 int of_property_match_string(struct device_node *np, const char *propname,
1315 struct property *prop = of_find_property(np, propname, NULL);
1318 const char *p, *end;
1326 end = p + prop->length;
1328 for (i = 0; p < end; i++, p += l) {
1329 l = strnlen(p, end - p) + 1;
1332 pr_debug("comparing %s with %s\n", string, p);
1333 if (strcmp(string, p) == 0)
1334 return i; /* Found it; return index */
1338 EXPORT_SYMBOL_GPL(of_property_match_string);
1341 * of_property_read_string_helper() - Utility helper for parsing string properties
1342 * @np: device node from which the property value is to be read.
1343 * @propname: name of the property to be searched.
1344 * @out_strs: output array of string pointers.
1345 * @sz: number of array elements to read.
1346 * @skip: Number of strings to skip over at beginning of list.
1348 * Don't call this function directly. It is a utility helper for the
1349 * of_property_read_string*() family of functions.
1351 int of_property_read_string_helper(struct device_node *np, const char *propname,
1352 const char **out_strs, size_t sz, int skip)
1354 struct property *prop = of_find_property(np, propname, NULL);
1356 const char *p, *end;
1363 end = p + prop->length;
1365 for (i = 0; p < end && (!out_strs || i < skip + sz); i++, p += l) {
1366 l = strnlen(p, end - p) + 1;
1369 if (out_strs && i >= skip)
1373 return i <= 0 ? -ENODATA : i;
1375 EXPORT_SYMBOL_GPL(of_property_read_string_helper);
1377 void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
1380 printk("%s %s", msg, of_node_full_name(args->np));
1381 for (i = 0; i < args->args_count; i++)
1382 printk(i ? ",%08x" : ":%08x", args->args[i]);
1386 static int __of_parse_phandle_with_args(const struct device_node *np,
1387 const char *list_name,
1388 const char *cells_name,
1389 int cell_count, int index,
1390 struct of_phandle_args *out_args)
1392 const __be32 *list, *list_end;
1393 int rc = 0, size, cur_index = 0;
1395 struct device_node *node = NULL;
1398 /* Retrieve the phandle list property */
1399 list = of_get_property(np, list_name, &size);
1402 list_end = list + size / sizeof(*list);
1404 /* Loop over the phandles until all the requested entry is found */
1405 while (list < list_end) {
1410 * If phandle is 0, then it is an empty entry with no
1411 * arguments. Skip forward to the next entry.
1413 phandle = be32_to_cpup(list++);
1416 * Find the provider node and parse the #*-cells
1417 * property to determine the argument length.
1419 * This is not needed if the cell count is hard-coded
1420 * (i.e. cells_name not set, but cell_count is set),
1421 * except when we're going to return the found node
1424 if (cells_name || cur_index == index) {
1425 node = of_find_node_by_phandle(phandle);
1427 pr_err("%s: could not find phandle\n",
1434 if (of_property_read_u32(node, cells_name,
1436 pr_err("%s: could not get %s for %s\n",
1437 np->full_name, cells_name,
1446 * Make sure that the arguments actually fit in the
1447 * remaining property data length
1449 if (list + count > list_end) {
1450 pr_err("%s: arguments longer than property\n",
1457 * All of the error cases above bail out of the loop, so at
1458 * this point, the parsing is successful. If the requested
1459 * index matches, then fill the out_args structure and return,
1460 * or return -ENOENT for an empty entry.
1463 if (cur_index == index) {
1469 if (WARN_ON(count > MAX_PHANDLE_ARGS))
1470 count = MAX_PHANDLE_ARGS;
1471 out_args->np = node;
1472 out_args->args_count = count;
1473 for (i = 0; i < count; i++)
1474 out_args->args[i] = be32_to_cpup(list++);
1479 /* Found it! return success */
1490 * Unlock node before returning result; will be one of:
1491 * -ENOENT : index is for empty phandle
1492 * -EINVAL : parsing error on data
1493 * [1..n] : Number of phandle (count mode; when index = -1)
1495 rc = index < 0 ? cur_index : -ENOENT;
1503 * of_parse_phandle - Resolve a phandle property to a device_node pointer
1504 * @np: Pointer to device node holding phandle property
1505 * @phandle_name: Name of property holding a phandle value
1506 * @index: For properties holding a table of phandles, this is the index into
1509 * Returns the device_node pointer with refcount incremented. Use
1510 * of_node_put() on it when done.
1512 struct device_node *of_parse_phandle(const struct device_node *np,
1513 const char *phandle_name, int index)
1515 struct of_phandle_args args;
1520 if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0,
1526 EXPORT_SYMBOL(of_parse_phandle);
1529 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
1530 * @np: pointer to a device tree node containing a list
1531 * @list_name: property name that contains a list
1532 * @cells_name: property name that specifies phandles' arguments count
1533 * @index: index of a phandle to parse out
1534 * @out_args: optional pointer to output arguments structure (will be filled)
1536 * This function is useful to parse lists of phandles and their arguments.
1537 * Returns 0 on success and fills out_args, on error returns appropriate
1540 * Caller is responsible to call of_node_put() on the returned out_args->np
1546 * #list-cells = <2>;
1550 * #list-cells = <1>;
1554 * list = <&phandle1 1 2 &phandle2 3>;
1557 * To get a device_node of the `node2' node you may call this:
1558 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
1560 int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
1561 const char *cells_name, int index,
1562 struct of_phandle_args *out_args)
1566 return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
1569 EXPORT_SYMBOL(of_parse_phandle_with_args);
1572 * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
1573 * @np: pointer to a device tree node containing a list
1574 * @list_name: property name that contains a list
1575 * @cell_count: number of argument cells following the phandle
1576 * @index: index of a phandle to parse out
1577 * @out_args: optional pointer to output arguments structure (will be filled)
1579 * This function is useful to parse lists of phandles and their arguments.
1580 * Returns 0 on success and fills out_args, on error returns appropriate
1583 * Caller is responsible to call of_node_put() on the returned out_args->np
1595 * list = <&phandle1 0 2 &phandle2 2 3>;
1598 * To get a device_node of the `node2' node you may call this:
1599 * of_parse_phandle_with_fixed_args(node3, "list", 2, 1, &args);
1601 int of_parse_phandle_with_fixed_args(const struct device_node *np,
1602 const char *list_name, int cell_count,
1603 int index, struct of_phandle_args *out_args)
1607 return __of_parse_phandle_with_args(np, list_name, NULL, cell_count,
1610 EXPORT_SYMBOL(of_parse_phandle_with_fixed_args);
1613 * of_count_phandle_with_args() - Find the number of phandles references in a property
1614 * @np: pointer to a device tree node containing a list
1615 * @list_name: property name that contains a list
1616 * @cells_name: property name that specifies phandles' arguments count
1618 * Returns the number of phandle + argument tuples within a property. It
1619 * is a typical pattern to encode a list of phandle and variable
1620 * arguments into a single property. The number of arguments is encoded
1621 * by a property in the phandle-target node. For example, a gpios
1622 * property would contain a list of GPIO specifies consisting of a
1623 * phandle and 1 or more arguments. The number of arguments are
1624 * determined by the #gpio-cells property in the node pointed to by the
1627 int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
1628 const char *cells_name)
1630 return __of_parse_phandle_with_args(np, list_name, cells_name, 0, -1,
1633 EXPORT_SYMBOL(of_count_phandle_with_args);
1636 * __of_add_property - Add a property to a node without lock operations
1638 int __of_add_property(struct device_node *np, struct property *prop)
1640 struct property **next;
1643 next = &np->properties;
1645 if (strcmp(prop->name, (*next)->name) == 0)
1646 /* duplicate ! don't insert it */
1649 next = &(*next)->next;
1657 * of_add_property - Add a property to a node
1659 int of_add_property(struct device_node *np, struct property *prop)
1661 unsigned long flags;
1664 mutex_lock(&of_mutex);
1666 raw_spin_lock_irqsave(&devtree_lock, flags);
1667 rc = __of_add_property(np, prop);
1668 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1671 __of_add_property_sysfs(np, prop);
1673 mutex_unlock(&of_mutex);
1676 of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop, NULL);
1681 int __of_remove_property(struct device_node *np, struct property *prop)
1683 struct property **next;
1685 for (next = &np->properties; *next; next = &(*next)->next) {
1692 /* found the node */
1694 prop->next = np->deadprops;
1695 np->deadprops = prop;
1700 void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
1702 if (!IS_ENABLED(CONFIG_SYSFS))
1705 /* at early boot, bail here and defer setup to of_init() */
1706 if (of_kset && of_node_is_attached(np))
1707 sysfs_remove_bin_file(&np->kobj, &prop->attr);
1711 * of_remove_property - Remove a property from a node.
1713 * Note that we don't actually remove it, since we have given out
1714 * who-knows-how-many pointers to the data using get-property.
1715 * Instead we just move the property to the "dead properties"
1716 * list, so it won't be found any more.
1718 int of_remove_property(struct device_node *np, struct property *prop)
1720 unsigned long flags;
1723 mutex_lock(&of_mutex);
1725 raw_spin_lock_irqsave(&devtree_lock, flags);
1726 rc = __of_remove_property(np, prop);
1727 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1730 __of_remove_property_sysfs(np, prop);
1732 mutex_unlock(&of_mutex);
1735 of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop, NULL);
1740 int __of_update_property(struct device_node *np, struct property *newprop,
1741 struct property **oldpropp)
1743 struct property **next, *oldprop;
1745 for (next = &np->properties; *next; next = &(*next)->next) {
1746 if (of_prop_cmp((*next)->name, newprop->name) == 0)
1749 *oldpropp = oldprop = *next;
1752 /* replace the node */
1753 newprop->next = oldprop->next;
1755 oldprop->next = np->deadprops;
1756 np->deadprops = oldprop;
1759 newprop->next = NULL;
1766 void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
1767 struct property *oldprop)
1769 if (!IS_ENABLED(CONFIG_SYSFS))
1772 /* At early boot, bail out and defer setup to of_init() */
1777 sysfs_remove_bin_file(&np->kobj, &oldprop->attr);
1778 __of_add_property_sysfs(np, newprop);
1782 * of_update_property - Update a property in a node, if the property does
1783 * not exist, add it.
1785 * Note that we don't actually remove it, since we have given out
1786 * who-knows-how-many pointers to the data using get-property.
1787 * Instead we just move the property to the "dead properties" list,
1788 * and add the new property to the property list
1790 int of_update_property(struct device_node *np, struct property *newprop)
1792 struct property *oldprop;
1793 unsigned long flags;
1799 mutex_lock(&of_mutex);
1801 raw_spin_lock_irqsave(&devtree_lock, flags);
1802 rc = __of_update_property(np, newprop, &oldprop);
1803 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1806 __of_update_property_sysfs(np, newprop, oldprop);
1808 mutex_unlock(&of_mutex);
1811 of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop, oldprop);
1816 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1817 int id, const char *stem, int stem_len)
1821 strncpy(ap->stem, stem, stem_len);
1822 ap->stem[stem_len] = 0;
1823 list_add_tail(&ap->link, &aliases_lookup);
1824 pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
1825 ap->alias, ap->stem, ap->id, of_node_full_name(np));
1829 * of_alias_scan - Scan all properties of the 'aliases' node
1831 * The function scans all the properties of the 'aliases' node and populates
1832 * the global lookup table with the properties. It returns the
1833 * number of alias properties found, or an error code in case of failure.
1835 * @dt_alloc: An allocator that provides a virtual address to memory
1836 * for storing the resulting tree
1838 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1840 struct property *pp;
1842 of_aliases = of_find_node_by_path("/aliases");
1843 of_chosen = of_find_node_by_path("/chosen");
1844 if (of_chosen == NULL)
1845 of_chosen = of_find_node_by_path("/chosen@0");
1848 /* linux,stdout-path and /aliases/stdout are for legacy compatibility */
1849 const char *name = of_get_property(of_chosen, "stdout-path", NULL);
1851 name = of_get_property(of_chosen, "linux,stdout-path", NULL);
1852 if (IS_ENABLED(CONFIG_PPC) && !name)
1853 name = of_get_property(of_aliases, "stdout", NULL);
1855 of_stdout = of_find_node_by_path(name);
1861 for_each_property_of_node(of_aliases, pp) {
1862 const char *start = pp->name;
1863 const char *end = start + strlen(start);
1864 struct device_node *np;
1865 struct alias_prop *ap;
1868 /* Skip those we do not want to proceed */
1869 if (!strcmp(pp->name, "name") ||
1870 !strcmp(pp->name, "phandle") ||
1871 !strcmp(pp->name, "linux,phandle"))
1874 np = of_find_node_by_path(pp->value);
1878 /* walk the alias backwards to extract the id and work out
1879 * the 'stem' string */
1880 while (isdigit(*(end-1)) && end > start)
1884 if (kstrtoint(end, 10, &id) < 0)
1887 /* Allocate an alias_prop with enough space for the stem */
1888 ap = dt_alloc(sizeof(*ap) + len + 1, 4);
1891 memset(ap, 0, sizeof(*ap) + len + 1);
1893 of_alias_add(ap, np, id, start, len);
1898 * of_alias_get_id - Get alias id for the given device_node
1899 * @np: Pointer to the given device_node
1900 * @stem: Alias stem of the given device_node
1902 * The function travels the lookup table to get the alias id for the given
1903 * device_node and alias stem. It returns the alias id if found.
1905 int of_alias_get_id(struct device_node *np, const char *stem)
1907 struct alias_prop *app;
1910 mutex_lock(&of_mutex);
1911 list_for_each_entry(app, &aliases_lookup, link) {
1912 if (strcmp(app->stem, stem) != 0)
1915 if (np == app->np) {
1920 mutex_unlock(&of_mutex);
1924 EXPORT_SYMBOL_GPL(of_alias_get_id);
1926 const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
1929 const void *curv = cur;
1939 curv += sizeof(*cur);
1940 if (curv >= prop->value + prop->length)
1944 *pu = be32_to_cpup(curv);
1947 EXPORT_SYMBOL_GPL(of_prop_next_u32);
1949 const char *of_prop_next_string(struct property *prop, const char *cur)
1951 const void *curv = cur;
1959 curv += strlen(cur) + 1;
1960 if (curv >= prop->value + prop->length)
1965 EXPORT_SYMBOL_GPL(of_prop_next_string);
1968 * of_console_check() - Test and setup console for DT setup
1969 * @dn - Pointer to device node
1970 * @name - Name to use for preferred console without index. ex. "ttyS"
1971 * @index - Index to use for preferred console.
1973 * Check if the given device node matches the stdout-path property in the
1974 * /chosen node. If it does then register it as the preferred console and return
1975 * TRUE. Otherwise return FALSE.
1977 bool of_console_check(struct device_node *dn, char *name, int index)
1979 if (!dn || dn != of_stdout || console_set_on_cmdline)
1981 return !add_preferred_console(name, index, NULL);
1983 EXPORT_SYMBOL_GPL(of_console_check);
1986 * of_find_next_cache_node - Find a node's subsidiary cache
1987 * @np: node of type "cpu" or "cache"
1989 * Returns a node pointer with refcount incremented, use
1990 * of_node_put() on it when done. Caller should hold a reference
1993 struct device_node *of_find_next_cache_node(const struct device_node *np)
1995 struct device_node *child;
1996 const phandle *handle;
1998 handle = of_get_property(np, "l2-cache", NULL);
2000 handle = of_get_property(np, "next-level-cache", NULL);
2003 return of_find_node_by_phandle(be32_to_cpup(handle));
2005 /* OF on pmac has nodes instead of properties named "l2-cache"
2006 * beneath CPU nodes.
2008 if (!strcmp(np->type, "cpu"))
2009 for_each_child_of_node(np, child)
2010 if (!strcmp(child->type, "cache"))
2017 * of_graph_parse_endpoint() - parse common endpoint node properties
2018 * @node: pointer to endpoint device_node
2019 * @endpoint: pointer to the OF endpoint data structure
2021 * The caller should hold a reference to @node.
2023 int of_graph_parse_endpoint(const struct device_node *node,
2024 struct of_endpoint *endpoint)
2026 struct device_node *port_node = of_get_parent(node);
2028 WARN_ONCE(!port_node, "%s(): endpoint %s has no parent node\n",
2029 __func__, node->full_name);
2031 memset(endpoint, 0, sizeof(*endpoint));
2033 endpoint->local_node = node;
2035 * It doesn't matter whether the two calls below succeed.
2036 * If they don't then the default value 0 is used.
2038 of_property_read_u32(port_node, "reg", &endpoint->port);
2039 of_property_read_u32(node, "reg", &endpoint->id);
2041 of_node_put(port_node);
2045 EXPORT_SYMBOL(of_graph_parse_endpoint);
2048 * of_graph_get_next_endpoint() - get next endpoint node
2049 * @parent: pointer to the parent device node
2050 * @prev: previous endpoint node, or NULL to get first
2052 * Return: An 'endpoint' node pointer with refcount incremented. Refcount
2053 * of the passed @prev node is not decremented, the caller have to use
2054 * of_node_put() on it when done.
2056 struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
2057 struct device_node *prev)
2059 struct device_node *endpoint;
2060 struct device_node *port;
2066 * Start by locating the port node. If no previous endpoint is specified
2067 * search for the first port node, otherwise get the previous endpoint
2071 struct device_node *node;
2073 node = of_get_child_by_name(parent, "ports");
2077 port = of_get_child_by_name(parent, "port");
2081 pr_err("%s(): no port node found in %s\n",
2082 __func__, parent->full_name);
2086 port = of_get_parent(prev);
2087 if (WARN_ONCE(!port, "%s(): endpoint %s has no parent node\n",
2088 __func__, prev->full_name))
2092 * Avoid dropping prev node refcount to 0 when getting the next
2100 * Now that we have a port node, get the next endpoint by
2101 * getting the next child. If the previous endpoint is NULL this
2102 * will return the first child.
2104 endpoint = of_get_next_child(port, prev);
2110 /* No more endpoints under this port, try the next one. */
2114 port = of_get_next_child(parent, port);
2117 } while (of_node_cmp(port->name, "port"));
2120 EXPORT_SYMBOL(of_graph_get_next_endpoint);
2123 * of_graph_get_remote_port_parent() - get remote port's parent node
2124 * @node: pointer to a local endpoint device_node
2126 * Return: Remote device node associated with remote endpoint node linked
2127 * to @node. Use of_node_put() on it when done.
2129 struct device_node *of_graph_get_remote_port_parent(
2130 const struct device_node *node)
2132 struct device_node *np;
2135 /* Get remote endpoint node. */
2136 np = of_parse_phandle(node, "remote-endpoint", 0);
2138 /* Walk 3 levels up only if there is 'ports' node. */
2139 for (depth = 3; depth && np; depth--) {
2140 np = of_get_next_parent(np);
2141 if (depth == 2 && of_node_cmp(np->name, "ports"))
2146 EXPORT_SYMBOL(of_graph_get_remote_port_parent);
2149 * of_graph_get_remote_port() - get remote port node
2150 * @node: pointer to a local endpoint device_node
2152 * Return: Remote port node associated with remote endpoint node linked
2153 * to @node. Use of_node_put() on it when done.
2155 struct device_node *of_graph_get_remote_port(const struct device_node *node)
2157 struct device_node *np;
2159 /* Get remote endpoint node. */
2160 np = of_parse_phandle(node, "remote-endpoint", 0);
2163 return of_get_next_parent(np);
2165 EXPORT_SYMBOL(of_graph_get_remote_port);