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.
21 #define pr_fmt(fmt) "OF: " fmt
23 #include <linux/console.h>
24 #include <linux/ctype.h>
25 #include <linux/cpu.h>
26 #include <linux/module.h>
28 #include <linux/of_device.h>
29 #include <linux/of_graph.h>
30 #include <linux/spinlock.h>
31 #include <linux/slab.h>
32 #include <linux/string.h>
33 #include <linux/proc_fs.h>
35 #include "of_private.h"
37 LIST_HEAD(aliases_lookup);
39 struct device_node *of_root;
40 EXPORT_SYMBOL(of_root);
41 struct device_node *of_chosen;
42 struct device_node *of_aliases;
43 struct device_node *of_stdout;
44 static const char *of_stdout_options;
49 * Used to protect the of_aliases, to hold off addition of nodes to sysfs.
50 * This mutex must be held whenever modifications are being made to the
51 * device tree. The of_{attach,detach}_node() and
52 * of_{add,remove,update}_property() helpers make sure this happens.
54 DEFINE_MUTEX(of_mutex);
56 /* use when traversing tree through the child, sibling,
57 * or parent members of struct device_node.
59 DEFINE_RAW_SPINLOCK(devtree_lock);
61 int of_n_addr_cells(struct device_node *np)
68 if (!of_property_read_u32(np, "#address-cells", &cells))
71 /* No #address-cells property for the root node */
72 return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
74 EXPORT_SYMBOL(of_n_addr_cells);
76 int of_n_size_cells(struct device_node *np)
83 if (!of_property_read_u32(np, "#size-cells", &cells))
86 /* No #size-cells property for the root node */
87 return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
89 EXPORT_SYMBOL(of_n_size_cells);
92 int __weak of_node_to_nid(struct device_node *np)
98 #ifndef CONFIG_OF_DYNAMIC
99 static void of_node_release(struct kobject *kobj)
101 /* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
103 #endif /* CONFIG_OF_DYNAMIC */
105 struct kobj_type of_node_ktype = {
106 .release = of_node_release,
109 static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
110 struct bin_attribute *bin_attr, char *buf,
111 loff_t offset, size_t count)
113 struct property *pp = container_of(bin_attr, struct property, attr);
114 return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
117 /* always return newly allocated name, caller must free after use */
118 static const char *safe_name(struct kobject *kobj, const char *orig_name)
120 const char *name = orig_name;
121 struct kernfs_node *kn;
124 /* don't be a hero. After 16 tries give up */
125 while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {
127 if (name != orig_name)
129 name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
132 if (name == orig_name) {
133 name = kstrdup(orig_name, GFP_KERNEL);
135 pr_warn("Duplicate name in %s, renamed to \"%s\"\n",
136 kobject_name(kobj), name);
141 int __of_add_property_sysfs(struct device_node *np, struct property *pp)
145 /* Important: Don't leak passwords */
146 bool secure = strncmp(pp->name, "security-", 9) == 0;
148 if (!IS_ENABLED(CONFIG_SYSFS))
151 if (!of_kset || !of_node_is_attached(np))
154 sysfs_bin_attr_init(&pp->attr);
155 pp->attr.attr.name = safe_name(&np->kobj, pp->name);
156 pp->attr.attr.mode = secure ? 0400 : 0444;
157 pp->attr.size = secure ? 0 : pp->length;
158 pp->attr.read = of_node_property_read;
160 rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
161 WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np);
165 int __of_attach_node_sysfs(struct device_node *np)
168 struct kobject *parent;
175 np->kobj.kset = of_kset;
177 /* Nodes without parents are new top level trees */
178 name = safe_name(&of_kset->kobj, "base");
181 name = safe_name(&np->parent->kobj, kbasename(np->full_name));
182 parent = &np->parent->kobj;
186 rc = kobject_add(&np->kobj, parent, "%s", name);
191 for_each_property_of_node(np, pp)
192 __of_add_property_sysfs(np, pp);
197 void __init of_core_init(void)
199 struct device_node *np;
201 /* Create the kset, and register existing nodes */
202 mutex_lock(&of_mutex);
203 of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj);
205 mutex_unlock(&of_mutex);
206 pr_err("failed to register existing nodes\n");
209 for_each_of_allnodes(np)
210 __of_attach_node_sysfs(np);
211 mutex_unlock(&of_mutex);
213 /* Symlink in /proc as required by userspace ABI */
215 proc_symlink("device-tree", NULL, "/sys/firmware/devicetree/base");
218 static struct property *__of_find_property(const struct device_node *np,
219 const char *name, int *lenp)
226 for (pp = np->properties; pp; pp = pp->next) {
227 if (of_prop_cmp(pp->name, name) == 0) {
237 struct property *of_find_property(const struct device_node *np,
244 raw_spin_lock_irqsave(&devtree_lock, flags);
245 pp = __of_find_property(np, name, lenp);
246 raw_spin_unlock_irqrestore(&devtree_lock, flags);
250 EXPORT_SYMBOL(of_find_property);
252 struct device_node *__of_find_all_nodes(struct device_node *prev)
254 struct device_node *np;
257 } else if (prev->child) {
260 /* Walk back up looking for a sibling, or the end of the structure */
262 while (np->parent && !np->sibling)
264 np = np->sibling; /* Might be null at the end of the tree */
270 * of_find_all_nodes - Get next node in global list
271 * @prev: Previous node or NULL to start iteration
272 * of_node_put() will be called on it
274 * Returns a node pointer with refcount incremented, use
275 * of_node_put() on it when done.
277 struct device_node *of_find_all_nodes(struct device_node *prev)
279 struct device_node *np;
282 raw_spin_lock_irqsave(&devtree_lock, flags);
283 np = __of_find_all_nodes(prev);
286 raw_spin_unlock_irqrestore(&devtree_lock, flags);
289 EXPORT_SYMBOL(of_find_all_nodes);
292 * Find a property with a given name for a given node
293 * and return the value.
295 const void *__of_get_property(const struct device_node *np,
296 const char *name, int *lenp)
298 struct property *pp = __of_find_property(np, name, lenp);
300 return pp ? pp->value : NULL;
304 * Find a property with a given name for a given node
305 * and return the value.
307 const void *of_get_property(const struct device_node *np, const char *name,
310 struct property *pp = of_find_property(np, name, lenp);
312 return pp ? pp->value : NULL;
314 EXPORT_SYMBOL(of_get_property);
317 * arch_match_cpu_phys_id - Match the given logical CPU and physical id
319 * @cpu: logical cpu index of a core/thread
320 * @phys_id: physical identifier of a core/thread
322 * CPU logical to physical index mapping is architecture specific.
323 * However this __weak function provides a default match of physical
324 * id to logical cpu index. phys_id provided here is usually values read
325 * from the device tree which must match the hardware internal registers.
327 * Returns true if the physical identifier and the logical cpu index
328 * correspond to the same core/thread, false otherwise.
330 bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id)
332 return (u32)phys_id == cpu;
336 * Checks if the given "prop_name" property holds the physical id of the
337 * core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not
338 * NULL, local thread number within the core is returned in it.
340 static bool __of_find_n_match_cpu_property(struct device_node *cpun,
341 const char *prop_name, int cpu, unsigned int *thread)
344 int ac, prop_len, tid;
347 ac = of_n_addr_cells(cpun);
348 cell = of_get_property(cpun, prop_name, &prop_len);
351 prop_len /= sizeof(*cell) * ac;
352 for (tid = 0; tid < prop_len; tid++) {
353 hwid = of_read_number(cell, ac);
354 if (arch_match_cpu_phys_id(cpu, hwid)) {
365 * arch_find_n_match_cpu_physical_id - See if the given device node is
366 * for the cpu corresponding to logical cpu 'cpu'. Return true if so,
367 * else false. If 'thread' is non-NULL, the local thread number within the
368 * core is returned in it.
370 bool __weak arch_find_n_match_cpu_physical_id(struct device_node *cpun,
371 int cpu, unsigned int *thread)
373 /* Check for non-standard "ibm,ppc-interrupt-server#s" property
374 * for thread ids on PowerPC. If it doesn't exist fallback to
375 * standard "reg" property.
377 if (IS_ENABLED(CONFIG_PPC) &&
378 __of_find_n_match_cpu_property(cpun,
379 "ibm,ppc-interrupt-server#s",
383 return __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 with refcount incremented, use
403 * of_node_put() on it when done. Returns NULL if not found.
405 struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
407 struct device_node *cpun;
409 for_each_node_by_type(cpun, "cpu") {
410 if (arch_find_n_match_cpu_physical_id(cpun, cpu, thread))
415 EXPORT_SYMBOL(of_get_cpu_node);
418 * __of_device_is_compatible() - Check if the node matches given constraints
419 * @device: pointer to node
420 * @compat: required compatible string, NULL or "" for any match
421 * @type: required device_type value, NULL or "" for any match
422 * @name: required node name, NULL or "" for any match
424 * Checks if the given @compat, @type and @name strings match the
425 * properties of the given @device. A constraints can be skipped by
426 * passing NULL or an empty string as the constraint.
428 * Returns 0 for no match, and a positive integer on match. The return
429 * value is a relative score with larger values indicating better
430 * matches. The score is weighted for the most specific compatible value
431 * to get the highest score. Matching type is next, followed by matching
432 * name. Practically speaking, this results in the following priority
435 * 1. specific compatible && type && name
436 * 2. specific compatible && type
437 * 3. specific compatible && name
438 * 4. specific compatible
439 * 5. general compatible && type && name
440 * 6. general compatible && type
441 * 7. general compatible && name
442 * 8. general compatible
447 static int __of_device_is_compatible(const struct device_node *device,
448 const char *compat, const char *type, const char *name)
450 struct property *prop;
452 int index = 0, score = 0;
454 /* Compatible match has highest priority */
455 if (compat && compat[0]) {
456 prop = __of_find_property(device, "compatible", NULL);
457 for (cp = of_prop_next_string(prop, NULL); cp;
458 cp = of_prop_next_string(prop, cp), index++) {
459 if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
460 score = INT_MAX/2 - (index << 2);
468 /* Matching type is better than matching name */
469 if (type && type[0]) {
470 if (!device->type || of_node_cmp(type, device->type))
475 /* Matching name is a bit better than not */
476 if (name && name[0]) {
477 if (!device->name || of_node_cmp(name, device->name))
485 /** Checks if the given "compat" string matches one of the strings in
486 * the device's "compatible" property
488 int of_device_is_compatible(const struct device_node *device,
494 raw_spin_lock_irqsave(&devtree_lock, flags);
495 res = __of_device_is_compatible(device, compat, NULL, NULL);
496 raw_spin_unlock_irqrestore(&devtree_lock, flags);
499 EXPORT_SYMBOL(of_device_is_compatible);
501 /** Checks if the device is compatible with any of the entries in
502 * a NULL terminated array of strings. Returns the best match
505 int of_device_compatible_match(struct device_node *device,
506 const char *const *compat)
508 unsigned int tmp, score = 0;
514 tmp = of_device_is_compatible(device, *compat);
524 * of_machine_is_compatible - Test root of device tree for a given compatible value
525 * @compat: compatible string to look for in root node's compatible property.
527 * Returns a positive integer if the root node has the given value in its
528 * compatible property.
530 int of_machine_is_compatible(const char *compat)
532 struct device_node *root;
535 root = of_find_node_by_path("/");
537 rc = of_device_is_compatible(root, compat);
542 EXPORT_SYMBOL(of_machine_is_compatible);
545 * __of_device_is_available - check if a device is available for use
547 * @device: Node to check for availability, with locks already held
549 * Returns true if the status property is absent or set to "okay" or "ok",
552 static bool __of_device_is_available(const struct device_node *device)
560 status = __of_get_property(device, "status", &statlen);
565 if (!strcmp(status, "okay") || !strcmp(status, "ok"))
573 * of_device_is_available - check if a device is available for use
575 * @device: Node to check for availability
577 * Returns true if the status property is absent or set to "okay" or "ok",
580 bool of_device_is_available(const struct device_node *device)
585 raw_spin_lock_irqsave(&devtree_lock, flags);
586 res = __of_device_is_available(device);
587 raw_spin_unlock_irqrestore(&devtree_lock, flags);
591 EXPORT_SYMBOL(of_device_is_available);
594 * of_device_is_big_endian - check if a device has BE registers
596 * @device: Node to check for endianness
598 * Returns true if the device has a "big-endian" property, or if the kernel
599 * was compiled for BE *and* the device has a "native-endian" property.
600 * Returns false otherwise.
602 * Callers would nominally use ioread32be/iowrite32be if
603 * of_device_is_big_endian() == true, or readl/writel otherwise.
605 bool of_device_is_big_endian(const struct device_node *device)
607 if (of_property_read_bool(device, "big-endian"))
609 if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
610 of_property_read_bool(device, "native-endian"))
614 EXPORT_SYMBOL(of_device_is_big_endian);
617 * of_get_parent - Get a node's parent if any
618 * @node: Node to get parent
620 * Returns a node pointer with refcount incremented, use
621 * of_node_put() on it when done.
623 struct device_node *of_get_parent(const struct device_node *node)
625 struct device_node *np;
631 raw_spin_lock_irqsave(&devtree_lock, flags);
632 np = of_node_get(node->parent);
633 raw_spin_unlock_irqrestore(&devtree_lock, flags);
636 EXPORT_SYMBOL(of_get_parent);
639 * of_get_next_parent - Iterate to a node's parent
640 * @node: Node to get parent of
642 * This is like of_get_parent() except that it drops the
643 * refcount on the passed node, making it suitable for iterating
644 * through a node's parents.
646 * Returns a node pointer with refcount incremented, use
647 * of_node_put() on it when done.
649 struct device_node *of_get_next_parent(struct device_node *node)
651 struct device_node *parent;
657 raw_spin_lock_irqsave(&devtree_lock, flags);
658 parent = of_node_get(node->parent);
660 raw_spin_unlock_irqrestore(&devtree_lock, flags);
663 EXPORT_SYMBOL(of_get_next_parent);
665 static struct device_node *__of_get_next_child(const struct device_node *node,
666 struct device_node *prev)
668 struct device_node *next;
673 next = prev ? prev->sibling : node->child;
674 for (; next; next = next->sibling)
675 if (of_node_get(next))
680 #define __for_each_child_of_node(parent, child) \
681 for (child = __of_get_next_child(parent, NULL); child != NULL; \
682 child = __of_get_next_child(parent, child))
685 * of_get_next_child - Iterate a node childs
687 * @prev: previous child of the parent node, or NULL to get first
689 * Returns a node pointer with refcount incremented, use of_node_put() on
690 * it when done. Returns NULL when prev is the last child. Decrements the
693 struct device_node *of_get_next_child(const struct device_node *node,
694 struct device_node *prev)
696 struct device_node *next;
699 raw_spin_lock_irqsave(&devtree_lock, flags);
700 next = __of_get_next_child(node, prev);
701 raw_spin_unlock_irqrestore(&devtree_lock, flags);
704 EXPORT_SYMBOL(of_get_next_child);
707 * of_get_next_available_child - Find the next available child node
709 * @prev: previous child of the parent node, or NULL to get first
711 * This function is like of_get_next_child(), except that it
712 * automatically skips any disabled nodes (i.e. status = "disabled").
714 struct device_node *of_get_next_available_child(const struct device_node *node,
715 struct device_node *prev)
717 struct device_node *next;
723 raw_spin_lock_irqsave(&devtree_lock, flags);
724 next = prev ? prev->sibling : node->child;
725 for (; next; next = next->sibling) {
726 if (!__of_device_is_available(next))
728 if (of_node_get(next))
732 raw_spin_unlock_irqrestore(&devtree_lock, flags);
735 EXPORT_SYMBOL(of_get_next_available_child);
738 * of_get_compatible_child - Find compatible child node
739 * @parent: parent node
740 * @compatible: compatible string
742 * Lookup child node whose compatible property contains the given compatible
745 * Returns a node pointer with refcount incremented, use of_node_put() on it
746 * when done; or NULL if not found.
748 struct device_node *of_get_compatible_child(const struct device_node *parent,
749 const char *compatible)
751 struct device_node *child;
753 for_each_child_of_node(parent, child) {
754 if (of_device_is_compatible(child, compatible))
760 EXPORT_SYMBOL(of_get_compatible_child);
763 * of_get_child_by_name - Find the child node by name for a given parent
765 * @name: child name to look for.
767 * This function looks for child node for given matching name
769 * Returns a node pointer if found, with refcount incremented, use
770 * of_node_put() on it when done.
771 * Returns NULL if node is not found.
773 struct device_node *of_get_child_by_name(const struct device_node *node,
776 struct device_node *child;
778 for_each_child_of_node(node, child)
779 if (child->name && (of_node_cmp(child->name, name) == 0))
783 EXPORT_SYMBOL(of_get_child_by_name);
785 static struct device_node *__of_find_node_by_path(struct device_node *parent,
788 struct device_node *child;
791 len = strcspn(path, "/:");
795 __for_each_child_of_node(parent, child) {
796 const char *name = kbasename(child->full_name);
797 if (strncmp(path, name, len) == 0 && (strlen(name) == len))
803 struct device_node *__of_find_node_by_full_path(struct device_node *node,
806 const char *separator = strchr(path, ':');
808 while (node && *path == '/') {
809 struct device_node *tmp = node;
811 path++; /* Increment past '/' delimiter */
812 node = __of_find_node_by_path(node, path);
814 path = strchrnul(path, '/');
815 if (separator && separator < path)
822 * of_find_node_opts_by_path - Find a node matching a full OF path
823 * @path: Either the full path to match, or if the path does not
824 * start with '/', the name of a property of the /aliases
825 * node (an alias). In the case of an alias, the node
826 * matching the alias' value will be returned.
827 * @opts: Address of a pointer into which to store the start of
828 * an options string appended to the end of the path with
834 * foo/bar Valid alias + relative path
836 * Returns a node pointer with refcount incremented, use
837 * of_node_put() on it when done.
839 struct device_node *of_find_node_opts_by_path(const char *path, const char **opts)
841 struct device_node *np = NULL;
844 const char *separator = strchr(path, ':');
847 *opts = separator ? separator + 1 : NULL;
849 if (strcmp(path, "/") == 0)
850 return of_node_get(of_root);
852 /* The path could begin with an alias */
855 const char *p = separator;
858 p = strchrnul(path, '/');
861 /* of_aliases must not be NULL */
865 for_each_property_of_node(of_aliases, pp) {
866 if (strlen(pp->name) == len && !strncmp(pp->name, path, len)) {
867 np = of_find_node_by_path(pp->value);
876 /* Step down the tree matching path components */
877 raw_spin_lock_irqsave(&devtree_lock, flags);
879 np = of_node_get(of_root);
880 np = __of_find_node_by_full_path(np, path);
881 raw_spin_unlock_irqrestore(&devtree_lock, flags);
884 EXPORT_SYMBOL(of_find_node_opts_by_path);
887 * of_find_node_by_name - Find a node by its "name" property
888 * @from: The node to start searching from or NULL, the node
889 * you pass will not be searched, only the next one
890 * will; typically, you pass what the previous call
891 * returned. of_node_put() will be called on it
892 * @name: The name string to match against
894 * Returns a node pointer with refcount incremented, use
895 * of_node_put() on it when done.
897 struct device_node *of_find_node_by_name(struct device_node *from,
900 struct device_node *np;
903 raw_spin_lock_irqsave(&devtree_lock, flags);
904 for_each_of_allnodes_from(from, np)
905 if (np->name && (of_node_cmp(np->name, name) == 0)
909 raw_spin_unlock_irqrestore(&devtree_lock, flags);
912 EXPORT_SYMBOL(of_find_node_by_name);
915 * of_find_node_by_type - Find a node by its "device_type" property
916 * @from: The node to start searching from, or NULL to start searching
917 * the entire device tree. The node you pass will not be
918 * searched, only the next one will; typically, you pass
919 * what the previous call returned. of_node_put() will be
920 * called on from for you.
921 * @type: The type string to match against
923 * Returns a node pointer with refcount incremented, use
924 * of_node_put() on it when done.
926 struct device_node *of_find_node_by_type(struct device_node *from,
929 struct device_node *np;
932 raw_spin_lock_irqsave(&devtree_lock, flags);
933 for_each_of_allnodes_from(from, np)
934 if (np->type && (of_node_cmp(np->type, type) == 0)
938 raw_spin_unlock_irqrestore(&devtree_lock, flags);
941 EXPORT_SYMBOL(of_find_node_by_type);
944 * of_find_compatible_node - Find a node based on type and one of the
945 * tokens in its "compatible" property
946 * @from: The node to start searching from or NULL, the node
947 * you pass will not be searched, only the next one
948 * will; typically, you pass what the previous call
949 * returned. of_node_put() will be called on it
950 * @type: The type string to match "device_type" or NULL to ignore
951 * @compatible: The string to match to one of the tokens in the device
954 * Returns a node pointer with refcount incremented, use
955 * of_node_put() on it when done.
957 struct device_node *of_find_compatible_node(struct device_node *from,
958 const char *type, const char *compatible)
960 struct device_node *np;
963 raw_spin_lock_irqsave(&devtree_lock, flags);
964 for_each_of_allnodes_from(from, np)
965 if (__of_device_is_compatible(np, compatible, type, NULL) &&
969 raw_spin_unlock_irqrestore(&devtree_lock, flags);
972 EXPORT_SYMBOL(of_find_compatible_node);
975 * of_find_node_with_property - Find a node which has a property with
977 * @from: The node to start searching from or NULL, the node
978 * you pass will not be searched, only the next one
979 * will; typically, you pass what the previous call
980 * returned. of_node_put() will be called on it
981 * @prop_name: The name of the property to look for.
983 * Returns a node pointer with refcount incremented, use
984 * of_node_put() on it when done.
986 struct device_node *of_find_node_with_property(struct device_node *from,
987 const char *prop_name)
989 struct device_node *np;
993 raw_spin_lock_irqsave(&devtree_lock, flags);
994 for_each_of_allnodes_from(from, np) {
995 for (pp = np->properties; pp; pp = pp->next) {
996 if (of_prop_cmp(pp->name, prop_name) == 0) {
1004 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1007 EXPORT_SYMBOL(of_find_node_with_property);
1010 const struct of_device_id *__of_match_node(const struct of_device_id *matches,
1011 const struct device_node *node)
1013 const struct of_device_id *best_match = NULL;
1014 int score, best_score = 0;
1019 for (; matches->name[0] || matches->type[0] || matches->compatible[0]; matches++) {
1020 score = __of_device_is_compatible(node, matches->compatible,
1021 matches->type, matches->name);
1022 if (score > best_score) {
1023 best_match = matches;
1032 * of_match_node - Tell if a device_node has a matching of_match structure
1033 * @matches: array of of device match structures to search in
1034 * @node: the of device structure to match against
1036 * Low level utility function used by device matching.
1038 const struct of_device_id *of_match_node(const struct of_device_id *matches,
1039 const struct device_node *node)
1041 const struct of_device_id *match;
1042 unsigned long flags;
1044 raw_spin_lock_irqsave(&devtree_lock, flags);
1045 match = __of_match_node(matches, node);
1046 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1049 EXPORT_SYMBOL(of_match_node);
1052 * of_find_matching_node_and_match - Find a node based on an of_device_id
1054 * @from: The node to start searching from or NULL, the node
1055 * you pass will not be searched, only the next one
1056 * will; typically, you pass what the previous call
1057 * returned. of_node_put() will be called on it
1058 * @matches: array of of device match structures to search in
1059 * @match Updated to point at the matches entry which matched
1061 * Returns a node pointer with refcount incremented, use
1062 * of_node_put() on it when done.
1064 struct device_node *of_find_matching_node_and_match(struct device_node *from,
1065 const struct of_device_id *matches,
1066 const struct of_device_id **match)
1068 struct device_node *np;
1069 const struct of_device_id *m;
1070 unsigned long flags;
1075 raw_spin_lock_irqsave(&devtree_lock, flags);
1076 for_each_of_allnodes_from(from, np) {
1077 m = __of_match_node(matches, np);
1078 if (m && of_node_get(np)) {
1085 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1088 EXPORT_SYMBOL(of_find_matching_node_and_match);
1091 * of_modalias_node - Lookup appropriate modalias for a device node
1092 * @node: pointer to a device tree node
1093 * @modalias: Pointer to buffer that modalias value will be copied into
1094 * @len: Length of modalias value
1096 * Based on the value of the compatible property, this routine will attempt
1097 * to choose an appropriate modalias value for a particular device tree node.
1098 * It does this by stripping the manufacturer prefix (as delimited by a ',')
1099 * from the first entry in the compatible list property.
1101 * This routine returns 0 on success, <0 on failure.
1103 int of_modalias_node(struct device_node *node, char *modalias, int len)
1105 const char *compatible, *p;
1108 compatible = of_get_property(node, "compatible", &cplen);
1109 if (!compatible || strlen(compatible) > cplen)
1111 p = strchr(compatible, ',');
1112 strlcpy(modalias, p ? p + 1 : compatible, len);
1115 EXPORT_SYMBOL_GPL(of_modalias_node);
1118 * of_find_node_by_phandle - Find a node given a phandle
1119 * @handle: phandle of the node to find
1121 * Returns a node pointer with refcount incremented, use
1122 * of_node_put() on it when done.
1124 struct device_node *of_find_node_by_phandle(phandle handle)
1126 struct device_node *np;
1127 unsigned long flags;
1132 raw_spin_lock_irqsave(&devtree_lock, flags);
1133 for_each_of_allnodes(np)
1134 if (np->phandle == handle)
1137 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1140 EXPORT_SYMBOL(of_find_node_by_phandle);
1142 void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
1145 printk("%s %pOF", msg, args->np);
1146 for (i = 0; i < args->args_count; i++) {
1147 const char delim = i ? ',' : ':';
1149 pr_cont("%c%08x", delim, args->args[i]);
1154 int of_phandle_iterator_init(struct of_phandle_iterator *it,
1155 const struct device_node *np,
1156 const char *list_name,
1157 const char *cells_name,
1163 memset(it, 0, sizeof(*it));
1165 list = of_get_property(np, list_name, &size);
1169 it->cells_name = cells_name;
1170 it->cell_count = cell_count;
1172 it->list_end = list + size / sizeof(*list);
1173 it->phandle_end = list;
1178 EXPORT_SYMBOL_GPL(of_phandle_iterator_init);
1180 int of_phandle_iterator_next(struct of_phandle_iterator *it)
1185 of_node_put(it->node);
1189 if (!it->cur || it->phandle_end >= it->list_end)
1192 it->cur = it->phandle_end;
1194 /* If phandle is 0, then it is an empty entry with no arguments. */
1195 it->phandle = be32_to_cpup(it->cur++);
1200 * Find the provider node and parse the #*-cells property to
1201 * determine the argument length.
1203 it->node = of_find_node_by_phandle(it->phandle);
1205 if (it->cells_name) {
1207 pr_err("%pOF: could not find phandle\n",
1212 if (of_property_read_u32(it->node, it->cells_name,
1214 pr_err("%pOF: could not get %s for %pOF\n",
1221 count = it->cell_count;
1225 * Make sure that the arguments actually fit in the remaining
1226 * property data length
1228 if (it->cur + count > it->list_end) {
1229 pr_err("%pOF: arguments longer than property\n",
1235 it->phandle_end = it->cur + count;
1236 it->cur_count = count;
1242 of_node_put(it->node);
1248 EXPORT_SYMBOL_GPL(of_phandle_iterator_next);
1250 int of_phandle_iterator_args(struct of_phandle_iterator *it,
1256 count = it->cur_count;
1258 if (WARN_ON(size < count))
1261 for (i = 0; i < count; i++)
1262 args[i] = be32_to_cpup(it->cur++);
1267 static int __of_parse_phandle_with_args(const struct device_node *np,
1268 const char *list_name,
1269 const char *cells_name,
1270 int cell_count, int index,
1271 struct of_phandle_args *out_args)
1273 struct of_phandle_iterator it;
1274 int rc, cur_index = 0;
1276 /* Loop over the phandles until all the requested entry is found */
1277 of_for_each_phandle(&it, rc, np, list_name, cells_name, cell_count) {
1279 * All of the error cases bail out of the loop, so at
1280 * this point, the parsing is successful. If the requested
1281 * index matches, then fill the out_args structure and return,
1282 * or return -ENOENT for an empty entry.
1285 if (cur_index == index) {
1292 c = of_phandle_iterator_args(&it,
1295 out_args->np = it.node;
1296 out_args->args_count = c;
1298 of_node_put(it.node);
1301 /* Found it! return success */
1309 * Unlock node before returning result; will be one of:
1310 * -ENOENT : index is for empty phandle
1311 * -EINVAL : parsing error on data
1315 of_node_put(it.node);
1320 * of_parse_phandle - Resolve a phandle property to a device_node pointer
1321 * @np: Pointer to device node holding phandle property
1322 * @phandle_name: Name of property holding a phandle value
1323 * @index: For properties holding a table of phandles, this is the index into
1326 * Returns the device_node pointer with refcount incremented. Use
1327 * of_node_put() on it when done.
1329 struct device_node *of_parse_phandle(const struct device_node *np,
1330 const char *phandle_name, int index)
1332 struct of_phandle_args args;
1337 if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0,
1343 EXPORT_SYMBOL(of_parse_phandle);
1346 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
1347 * @np: pointer to a device tree node containing a list
1348 * @list_name: property name that contains a list
1349 * @cells_name: property name that specifies phandles' arguments count
1350 * @index: index of a phandle to parse out
1351 * @out_args: optional pointer to output arguments structure (will be filled)
1353 * This function is useful to parse lists of phandles and their arguments.
1354 * Returns 0 on success and fills out_args, on error returns appropriate
1357 * Caller is responsible to call of_node_put() on the returned out_args->np
1363 * #list-cells = <2>;
1367 * #list-cells = <1>;
1371 * list = <&phandle1 1 2 &phandle2 3>;
1374 * To get a device_node of the `node2' node you may call this:
1375 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
1377 int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
1378 const char *cells_name, int index,
1379 struct of_phandle_args *out_args)
1383 return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
1386 EXPORT_SYMBOL(of_parse_phandle_with_args);
1389 * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
1390 * @np: pointer to a device tree node containing a list
1391 * @list_name: property name that contains a list
1392 * @cell_count: number of argument cells following the phandle
1393 * @index: index of a phandle to parse out
1394 * @out_args: optional pointer to output arguments structure (will be filled)
1396 * This function is useful to parse lists of phandles and their arguments.
1397 * Returns 0 on success and fills out_args, on error returns appropriate
1400 * Caller is responsible to call of_node_put() on the returned out_args->np
1412 * list = <&phandle1 0 2 &phandle2 2 3>;
1415 * To get a device_node of the `node2' node you may call this:
1416 * of_parse_phandle_with_fixed_args(node3, "list", 2, 1, &args);
1418 int of_parse_phandle_with_fixed_args(const struct device_node *np,
1419 const char *list_name, int cell_count,
1420 int index, struct of_phandle_args *out_args)
1424 return __of_parse_phandle_with_args(np, list_name, NULL, cell_count,
1427 EXPORT_SYMBOL(of_parse_phandle_with_fixed_args);
1430 * of_count_phandle_with_args() - Find the number of phandles references in a property
1431 * @np: pointer to a device tree node containing a list
1432 * @list_name: property name that contains a list
1433 * @cells_name: property name that specifies phandles' arguments count
1435 * Returns the number of phandle + argument tuples within a property. It
1436 * is a typical pattern to encode a list of phandle and variable
1437 * arguments into a single property. The number of arguments is encoded
1438 * by a property in the phandle-target node. For example, a gpios
1439 * property would contain a list of GPIO specifies consisting of a
1440 * phandle and 1 or more arguments. The number of arguments are
1441 * determined by the #gpio-cells property in the node pointed to by the
1444 int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
1445 const char *cells_name)
1447 struct of_phandle_iterator it;
1448 int rc, cur_index = 0;
1450 rc = of_phandle_iterator_init(&it, np, list_name, cells_name, 0);
1454 while ((rc = of_phandle_iterator_next(&it)) == 0)
1462 EXPORT_SYMBOL(of_count_phandle_with_args);
1465 * __of_add_property - Add a property to a node without lock operations
1467 int __of_add_property(struct device_node *np, struct property *prop)
1469 struct property **next;
1472 next = &np->properties;
1474 if (strcmp(prop->name, (*next)->name) == 0)
1475 /* duplicate ! don't insert it */
1478 next = &(*next)->next;
1486 * of_add_property - Add a property to a node
1488 int of_add_property(struct device_node *np, struct property *prop)
1490 unsigned long flags;
1493 mutex_lock(&of_mutex);
1495 raw_spin_lock_irqsave(&devtree_lock, flags);
1496 rc = __of_add_property(np, prop);
1497 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1500 __of_add_property_sysfs(np, prop);
1502 mutex_unlock(&of_mutex);
1505 of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop, NULL);
1510 int __of_remove_property(struct device_node *np, struct property *prop)
1512 struct property **next;
1514 for (next = &np->properties; *next; next = &(*next)->next) {
1521 /* found the node */
1523 prop->next = np->deadprops;
1524 np->deadprops = prop;
1529 void __of_sysfs_remove_bin_file(struct device_node *np, struct property *prop)
1531 sysfs_remove_bin_file(&np->kobj, &prop->attr);
1532 kfree(prop->attr.attr.name);
1535 void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
1537 if (!IS_ENABLED(CONFIG_SYSFS))
1540 /* at early boot, bail here and defer setup to of_init() */
1541 if (of_kset && of_node_is_attached(np))
1542 __of_sysfs_remove_bin_file(np, prop);
1546 * of_remove_property - Remove a property from a node.
1548 * Note that we don't actually remove it, since we have given out
1549 * who-knows-how-many pointers to the data using get-property.
1550 * Instead we just move the property to the "dead properties"
1551 * list, so it won't be found any more.
1553 int of_remove_property(struct device_node *np, struct property *prop)
1555 unsigned long flags;
1561 mutex_lock(&of_mutex);
1563 raw_spin_lock_irqsave(&devtree_lock, flags);
1564 rc = __of_remove_property(np, prop);
1565 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1568 __of_remove_property_sysfs(np, prop);
1570 mutex_unlock(&of_mutex);
1573 of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop, NULL);
1578 int __of_update_property(struct device_node *np, struct property *newprop,
1579 struct property **oldpropp)
1581 struct property **next, *oldprop;
1583 for (next = &np->properties; *next; next = &(*next)->next) {
1584 if (of_prop_cmp((*next)->name, newprop->name) == 0)
1587 *oldpropp = oldprop = *next;
1590 /* replace the node */
1591 newprop->next = oldprop->next;
1593 oldprop->next = np->deadprops;
1594 np->deadprops = oldprop;
1597 newprop->next = NULL;
1604 void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
1605 struct property *oldprop)
1607 if (!IS_ENABLED(CONFIG_SYSFS))
1610 /* At early boot, bail out and defer setup to of_init() */
1615 __of_sysfs_remove_bin_file(np, oldprop);
1616 __of_add_property_sysfs(np, newprop);
1620 * of_update_property - Update a property in a node, if the property does
1621 * not exist, add it.
1623 * Note that we don't actually remove it, since we have given out
1624 * who-knows-how-many pointers to the data using get-property.
1625 * Instead we just move the property to the "dead properties" list,
1626 * and add the new property to the property list
1628 int of_update_property(struct device_node *np, struct property *newprop)
1630 struct property *oldprop;
1631 unsigned long flags;
1637 mutex_lock(&of_mutex);
1639 raw_spin_lock_irqsave(&devtree_lock, flags);
1640 rc = __of_update_property(np, newprop, &oldprop);
1641 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1644 __of_update_property_sysfs(np, newprop, oldprop);
1646 mutex_unlock(&of_mutex);
1649 of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop, oldprop);
1654 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1655 int id, const char *stem, int stem_len)
1659 strncpy(ap->stem, stem, stem_len);
1660 ap->stem[stem_len] = 0;
1661 list_add_tail(&ap->link, &aliases_lookup);
1662 pr_debug("adding DT alias:%s: stem=%s id=%i node=%pOF\n",
1663 ap->alias, ap->stem, ap->id, np);
1667 * of_alias_scan - Scan all properties of the 'aliases' node
1669 * The function scans all the properties of the 'aliases' node and populates
1670 * the global lookup table with the properties. It returns the
1671 * number of alias properties found, or an error code in case of failure.
1673 * @dt_alloc: An allocator that provides a virtual address to memory
1674 * for storing the resulting tree
1676 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1678 struct property *pp;
1680 of_aliases = of_find_node_by_path("/aliases");
1681 of_chosen = of_find_node_by_path("/chosen");
1682 if (of_chosen == NULL)
1683 of_chosen = of_find_node_by_path("/chosen@0");
1686 /* linux,stdout-path and /aliases/stdout are for legacy compatibility */
1687 const char *name = NULL;
1689 if (of_property_read_string(of_chosen, "stdout-path", &name))
1690 of_property_read_string(of_chosen, "linux,stdout-path",
1692 if (IS_ENABLED(CONFIG_PPC) && !name)
1693 of_property_read_string(of_aliases, "stdout", &name);
1695 of_stdout = of_find_node_opts_by_path(name, &of_stdout_options);
1701 for_each_property_of_node(of_aliases, pp) {
1702 const char *start = pp->name;
1703 const char *end = start + strlen(start);
1704 struct device_node *np;
1705 struct alias_prop *ap;
1708 /* Skip those we do not want to proceed */
1709 if (!strcmp(pp->name, "name") ||
1710 !strcmp(pp->name, "phandle") ||
1711 !strcmp(pp->name, "linux,phandle"))
1714 np = of_find_node_by_path(pp->value);
1718 /* walk the alias backwards to extract the id and work out
1719 * the 'stem' string */
1720 while (isdigit(*(end-1)) && end > start)
1724 if (kstrtoint(end, 10, &id) < 0)
1727 /* Allocate an alias_prop with enough space for the stem */
1728 ap = dt_alloc(sizeof(*ap) + len + 1, __alignof__(*ap));
1731 memset(ap, 0, sizeof(*ap) + len + 1);
1733 of_alias_add(ap, np, id, start, len);
1738 * of_alias_get_id - Get alias id for the given device_node
1739 * @np: Pointer to the given device_node
1740 * @stem: Alias stem of the given device_node
1742 * The function travels the lookup table to get the alias id for the given
1743 * device_node and alias stem. It returns the alias id if found.
1745 int of_alias_get_id(struct device_node *np, const char *stem)
1747 struct alias_prop *app;
1750 mutex_lock(&of_mutex);
1751 list_for_each_entry(app, &aliases_lookup, link) {
1752 if (strcmp(app->stem, stem) != 0)
1755 if (np == app->np) {
1760 mutex_unlock(&of_mutex);
1764 EXPORT_SYMBOL_GPL(of_alias_get_id);
1767 * of_alias_get_highest_id - Get highest alias id for the given stem
1768 * @stem: Alias stem to be examined
1770 * The function travels the lookup table to get the highest alias id for the
1771 * given alias stem. It returns the alias id if found.
1773 int of_alias_get_highest_id(const char *stem)
1775 struct alias_prop *app;
1778 mutex_lock(&of_mutex);
1779 list_for_each_entry(app, &aliases_lookup, link) {
1780 if (strcmp(app->stem, stem) != 0)
1786 mutex_unlock(&of_mutex);
1790 EXPORT_SYMBOL_GPL(of_alias_get_highest_id);
1793 * of_console_check() - Test and setup console for DT setup
1794 * @dn - Pointer to device node
1795 * @name - Name to use for preferred console without index. ex. "ttyS"
1796 * @index - Index to use for preferred console.
1798 * Check if the given device node matches the stdout-path property in the
1799 * /chosen node. If it does then register it as the preferred console and return
1800 * TRUE. Otherwise return FALSE.
1802 bool of_console_check(struct device_node *dn, char *name, int index)
1804 if (!dn || dn != of_stdout || console_set_on_cmdline)
1808 * XXX: cast `options' to char pointer to suppress complication
1809 * warnings: printk, UART and console drivers expect char pointer.
1811 return !add_preferred_console(name, index, (char *)of_stdout_options);
1813 EXPORT_SYMBOL_GPL(of_console_check);
1816 * of_find_next_cache_node - Find a node's subsidiary cache
1817 * @np: node of type "cpu" or "cache"
1819 * Returns a node pointer with refcount incremented, use
1820 * of_node_put() on it when done. Caller should hold a reference
1823 struct device_node *of_find_next_cache_node(const struct device_node *np)
1825 struct device_node *child, *cache_node;
1827 cache_node = of_parse_phandle(np, "l2-cache", 0);
1829 cache_node = of_parse_phandle(np, "next-level-cache", 0);
1834 /* OF on pmac has nodes instead of properties named "l2-cache"
1835 * beneath CPU nodes.
1837 if (IS_ENABLED(CONFIG_PPC_PMAC) && !strcmp(np->type, "cpu"))
1838 for_each_child_of_node(np, child)
1839 if (!strcmp(child->type, "cache"))
1846 * of_find_last_cache_level - Find the level at which the last cache is
1847 * present for the given logical cpu
1849 * @cpu: cpu number(logical index) for which the last cache level is needed
1851 * Returns the the level at which the last cache is present. It is exactly
1852 * same as the total number of cache levels for the given logical cpu.
1854 int of_find_last_cache_level(unsigned int cpu)
1856 u32 cache_level = 0;
1857 struct device_node *prev = NULL, *np = of_cpu_device_node_get(cpu);
1862 np = of_find_next_cache_node(np);
1865 of_property_read_u32(prev, "cache-level", &cache_level);