1 // SPDX-License-Identifier: GPL-2.0+
3 * Procedures for creating, accessing and interpreting the device tree.
5 * Paul Mackerras August 1996.
6 * Copyright (C) 1996-2005 Paul Mackerras.
8 * Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
9 * {engebret|bergner}@us.ibm.com
11 * Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
13 * Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
17 #define pr_fmt(fmt) "OF: " fmt
19 #include <linux/console.h>
20 #include <linux/ctype.h>
21 #include <linux/cpu.h>
22 #include <linux/module.h>
24 #include <linux/of_device.h>
25 #include <linux/of_graph.h>
26 #include <linux/spinlock.h>
27 #include <linux/slab.h>
28 #include <linux/string.h>
29 #include <linux/proc_fs.h>
31 #include "of_private.h"
33 LIST_HEAD(aliases_lookup);
35 struct device_node *of_root;
36 EXPORT_SYMBOL(of_root);
37 struct device_node *of_chosen;
38 struct device_node *of_aliases;
39 struct device_node *of_stdout;
40 static const char *of_stdout_options;
45 * Used to protect the of_aliases, to hold off addition of nodes to sysfs.
46 * This mutex must be held whenever modifications are being made to the
47 * device tree. The of_{attach,detach}_node() and
48 * of_{add,remove,update}_property() helpers make sure this happens.
50 DEFINE_MUTEX(of_mutex);
52 /* use when traversing tree through the child, sibling,
53 * or parent members of struct device_node.
55 DEFINE_RAW_SPINLOCK(devtree_lock);
57 int of_n_addr_cells(struct device_node *np)
64 if (!of_property_read_u32(np, "#address-cells", &cells))
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 if (!of_property_read_u32(np, "#size-cells", &cells))
82 /* No #size-cells property for the root node */
83 return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
85 EXPORT_SYMBOL(of_n_size_cells);
88 int __weak of_node_to_nid(struct device_node *np)
94 static struct device_node **phandle_cache;
95 static u32 phandle_cache_mask;
98 * Assumptions behind phandle_cache implementation:
99 * - phandle property values are in a contiguous range of 1..n
101 * If the assumptions do not hold, then
102 * - the phandle lookup overhead reduction provided by the cache
103 * will likely be less
105 static void of_populate_phandle_cache(void)
109 struct device_node *np;
112 raw_spin_lock_irqsave(&devtree_lock, flags);
114 kfree(phandle_cache);
115 phandle_cache = NULL;
117 for_each_of_allnodes(np)
118 if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
121 cache_entries = roundup_pow_of_two(phandles);
122 phandle_cache_mask = cache_entries - 1;
124 phandle_cache = kcalloc(cache_entries, sizeof(*phandle_cache),
129 for_each_of_allnodes(np)
130 if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
131 phandle_cache[np->phandle & phandle_cache_mask] = np;
134 raw_spin_unlock_irqrestore(&devtree_lock, flags);
137 #ifndef CONFIG_MODULES
138 static int __init of_free_phandle_cache(void)
142 raw_spin_lock_irqsave(&devtree_lock, flags);
144 kfree(phandle_cache);
145 phandle_cache = NULL;
147 raw_spin_unlock_irqrestore(&devtree_lock, flags);
151 late_initcall_sync(of_free_phandle_cache);
154 void __init of_core_init(void)
156 struct device_node *np;
158 of_populate_phandle_cache();
160 /* Create the kset, and register existing nodes */
161 mutex_lock(&of_mutex);
162 of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj);
164 mutex_unlock(&of_mutex);
165 pr_err("failed to register existing nodes\n");
168 for_each_of_allnodes(np)
169 __of_attach_node_sysfs(np);
170 mutex_unlock(&of_mutex);
172 /* Symlink in /proc as required by userspace ABI */
174 proc_symlink("device-tree", NULL, "/sys/firmware/devicetree/base");
177 static struct property *__of_find_property(const struct device_node *np,
178 const char *name, int *lenp)
185 for (pp = np->properties; pp; pp = pp->next) {
186 if (of_prop_cmp(pp->name, name) == 0) {
196 struct property *of_find_property(const struct device_node *np,
203 raw_spin_lock_irqsave(&devtree_lock, flags);
204 pp = __of_find_property(np, name, lenp);
205 raw_spin_unlock_irqrestore(&devtree_lock, flags);
209 EXPORT_SYMBOL(of_find_property);
211 struct device_node *__of_find_all_nodes(struct device_node *prev)
213 struct device_node *np;
216 } else if (prev->child) {
219 /* Walk back up looking for a sibling, or the end of the structure */
221 while (np->parent && !np->sibling)
223 np = np->sibling; /* Might be null at the end of the tree */
229 * of_find_all_nodes - Get next node in global list
230 * @prev: Previous node or NULL to start iteration
231 * of_node_put() will be called on it
233 * Returns a node pointer with refcount incremented, use
234 * of_node_put() on it when done.
236 struct device_node *of_find_all_nodes(struct device_node *prev)
238 struct device_node *np;
241 raw_spin_lock_irqsave(&devtree_lock, flags);
242 np = __of_find_all_nodes(prev);
245 raw_spin_unlock_irqrestore(&devtree_lock, flags);
248 EXPORT_SYMBOL(of_find_all_nodes);
251 * Find a property with a given name for a given node
252 * and return the value.
254 const void *__of_get_property(const struct device_node *np,
255 const char *name, int *lenp)
257 struct property *pp = __of_find_property(np, name, lenp);
259 return pp ? pp->value : NULL;
263 * Find a property with a given name for a given node
264 * and return the value.
266 const void *of_get_property(const struct device_node *np, const char *name,
269 struct property *pp = of_find_property(np, name, lenp);
271 return pp ? pp->value : NULL;
273 EXPORT_SYMBOL(of_get_property);
276 * arch_match_cpu_phys_id - Match the given logical CPU and physical id
278 * @cpu: logical cpu index of a core/thread
279 * @phys_id: physical identifier of a core/thread
281 * CPU logical to physical index mapping is architecture specific.
282 * However this __weak function provides a default match of physical
283 * id to logical cpu index. phys_id provided here is usually values read
284 * from the device tree which must match the hardware internal registers.
286 * Returns true if the physical identifier and the logical cpu index
287 * correspond to the same core/thread, false otherwise.
289 bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id)
291 return (u32)phys_id == cpu;
295 * Checks if the given "prop_name" property holds the physical id of the
296 * core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not
297 * NULL, local thread number within the core is returned in it.
299 static bool __of_find_n_match_cpu_property(struct device_node *cpun,
300 const char *prop_name, int cpu, unsigned int *thread)
303 int ac, prop_len, tid;
306 ac = of_n_addr_cells(cpun);
307 cell = of_get_property(cpun, prop_name, &prop_len);
310 prop_len /= sizeof(*cell) * ac;
311 for (tid = 0; tid < prop_len; tid++) {
312 hwid = of_read_number(cell, ac);
313 if (arch_match_cpu_phys_id(cpu, hwid)) {
324 * arch_find_n_match_cpu_physical_id - See if the given device node is
325 * for the cpu corresponding to logical cpu 'cpu'. Return true if so,
326 * else false. If 'thread' is non-NULL, the local thread number within the
327 * core is returned in it.
329 bool __weak arch_find_n_match_cpu_physical_id(struct device_node *cpun,
330 int cpu, unsigned int *thread)
332 /* Check for non-standard "ibm,ppc-interrupt-server#s" property
333 * for thread ids on PowerPC. If it doesn't exist fallback to
334 * standard "reg" property.
336 if (IS_ENABLED(CONFIG_PPC) &&
337 __of_find_n_match_cpu_property(cpun,
338 "ibm,ppc-interrupt-server#s",
342 return __of_find_n_match_cpu_property(cpun, "reg", cpu, thread);
346 * of_get_cpu_node - Get device node associated with the given logical CPU
348 * @cpu: CPU number(logical index) for which device node is required
349 * @thread: if not NULL, local thread number within the physical core is
352 * The main purpose of this function is to retrieve the device node for the
353 * given logical CPU index. It should be used to initialize the of_node in
354 * cpu device. Once of_node in cpu device is populated, all the further
355 * references can use that instead.
357 * CPU logical to physical index mapping is architecture specific and is built
358 * before booting secondary cores. This function uses arch_match_cpu_phys_id
359 * which can be overridden by architecture specific implementation.
361 * Returns a node pointer for the logical cpu with refcount incremented, use
362 * of_node_put() on it when done. Returns NULL if not found.
364 struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
366 struct device_node *cpun;
368 for_each_node_by_type(cpun, "cpu") {
369 if (arch_find_n_match_cpu_physical_id(cpun, cpu, thread))
374 EXPORT_SYMBOL(of_get_cpu_node);
377 * of_cpu_node_to_id: Get the logical CPU number for a given device_node
379 * @cpu_node: Pointer to the device_node for CPU.
381 * Returns the logical CPU number of the given CPU device_node.
382 * Returns -ENODEV if the CPU is not found.
384 int of_cpu_node_to_id(struct device_node *cpu_node)
388 struct device_node *np;
390 for_each_possible_cpu(cpu) {
391 np = of_cpu_device_node_get(cpu);
392 found = (cpu_node == np);
400 EXPORT_SYMBOL(of_cpu_node_to_id);
403 * __of_device_is_compatible() - Check if the node matches given constraints
404 * @device: pointer to node
405 * @compat: required compatible string, NULL or "" for any match
406 * @type: required device_type value, NULL or "" for any match
407 * @name: required node name, NULL or "" for any match
409 * Checks if the given @compat, @type and @name strings match the
410 * properties of the given @device. A constraints can be skipped by
411 * passing NULL or an empty string as the constraint.
413 * Returns 0 for no match, and a positive integer on match. The return
414 * value is a relative score with larger values indicating better
415 * matches. The score is weighted for the most specific compatible value
416 * to get the highest score. Matching type is next, followed by matching
417 * name. Practically speaking, this results in the following priority
420 * 1. specific compatible && type && name
421 * 2. specific compatible && type
422 * 3. specific compatible && name
423 * 4. specific compatible
424 * 5. general compatible && type && name
425 * 6. general compatible && type
426 * 7. general compatible && name
427 * 8. general compatible
432 static int __of_device_is_compatible(const struct device_node *device,
433 const char *compat, const char *type, const char *name)
435 struct property *prop;
437 int index = 0, score = 0;
439 /* Compatible match has highest priority */
440 if (compat && compat[0]) {
441 prop = __of_find_property(device, "compatible", NULL);
442 for (cp = of_prop_next_string(prop, NULL); cp;
443 cp = of_prop_next_string(prop, cp), index++) {
444 if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
445 score = INT_MAX/2 - (index << 2);
453 /* Matching type is better than matching name */
454 if (type && type[0]) {
455 if (!device->type || of_node_cmp(type, device->type))
460 /* Matching name is a bit better than not */
461 if (name && name[0]) {
462 if (!device->name || of_node_cmp(name, device->name))
470 /** Checks if the given "compat" string matches one of the strings in
471 * the device's "compatible" property
473 int of_device_is_compatible(const struct device_node *device,
479 raw_spin_lock_irqsave(&devtree_lock, flags);
480 res = __of_device_is_compatible(device, compat, NULL, NULL);
481 raw_spin_unlock_irqrestore(&devtree_lock, flags);
484 EXPORT_SYMBOL(of_device_is_compatible);
486 /** Checks if the device is compatible with any of the entries in
487 * a NULL terminated array of strings. Returns the best match
490 int of_device_compatible_match(struct device_node *device,
491 const char *const *compat)
493 unsigned int tmp, score = 0;
499 tmp = of_device_is_compatible(device, *compat);
509 * of_machine_is_compatible - Test root of device tree for a given compatible value
510 * @compat: compatible string to look for in root node's compatible property.
512 * Returns a positive integer if the root node has the given value in its
513 * compatible property.
515 int of_machine_is_compatible(const char *compat)
517 struct device_node *root;
520 root = of_find_node_by_path("/");
522 rc = of_device_is_compatible(root, compat);
527 EXPORT_SYMBOL(of_machine_is_compatible);
530 * __of_device_is_available - check if a device is available for use
532 * @device: Node to check for availability, with locks already held
534 * Returns true if the status property is absent or set to "okay" or "ok",
537 static bool __of_device_is_available(const struct device_node *device)
545 status = __of_get_property(device, "status", &statlen);
550 if (!strcmp(status, "okay") || !strcmp(status, "ok"))
558 * of_device_is_available - check if a device is available for use
560 * @device: Node to check for availability
562 * Returns true if the status property is absent or set to "okay" or "ok",
565 bool of_device_is_available(const struct device_node *device)
570 raw_spin_lock_irqsave(&devtree_lock, flags);
571 res = __of_device_is_available(device);
572 raw_spin_unlock_irqrestore(&devtree_lock, flags);
576 EXPORT_SYMBOL(of_device_is_available);
579 * of_device_is_big_endian - check if a device has BE registers
581 * @device: Node to check for endianness
583 * Returns true if the device has a "big-endian" property, or if the kernel
584 * was compiled for BE *and* the device has a "native-endian" property.
585 * Returns false otherwise.
587 * Callers would nominally use ioread32be/iowrite32be if
588 * of_device_is_big_endian() == true, or readl/writel otherwise.
590 bool of_device_is_big_endian(const struct device_node *device)
592 if (of_property_read_bool(device, "big-endian"))
594 if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
595 of_property_read_bool(device, "native-endian"))
599 EXPORT_SYMBOL(of_device_is_big_endian);
602 * of_get_parent - Get a node's parent if any
603 * @node: Node to get parent
605 * Returns a node pointer with refcount incremented, use
606 * of_node_put() on it when done.
608 struct device_node *of_get_parent(const struct device_node *node)
610 struct device_node *np;
616 raw_spin_lock_irqsave(&devtree_lock, flags);
617 np = of_node_get(node->parent);
618 raw_spin_unlock_irqrestore(&devtree_lock, flags);
621 EXPORT_SYMBOL(of_get_parent);
624 * of_get_next_parent - Iterate to a node's parent
625 * @node: Node to get parent of
627 * This is like of_get_parent() except that it drops the
628 * refcount on the passed node, making it suitable for iterating
629 * through a node's parents.
631 * Returns a node pointer with refcount incremented, use
632 * of_node_put() on it when done.
634 struct device_node *of_get_next_parent(struct device_node *node)
636 struct device_node *parent;
642 raw_spin_lock_irqsave(&devtree_lock, flags);
643 parent = of_node_get(node->parent);
645 raw_spin_unlock_irqrestore(&devtree_lock, flags);
648 EXPORT_SYMBOL(of_get_next_parent);
650 static struct device_node *__of_get_next_child(const struct device_node *node,
651 struct device_node *prev)
653 struct device_node *next;
658 next = prev ? prev->sibling : node->child;
659 for (; next; next = next->sibling)
660 if (of_node_get(next))
665 #define __for_each_child_of_node(parent, child) \
666 for (child = __of_get_next_child(parent, NULL); child != NULL; \
667 child = __of_get_next_child(parent, child))
670 * of_get_next_child - Iterate a node childs
672 * @prev: previous child of the parent node, or NULL to get first
674 * Returns a node pointer with refcount incremented, use of_node_put() on
675 * it when done. Returns NULL when prev is the last child. Decrements the
678 struct device_node *of_get_next_child(const struct device_node *node,
679 struct device_node *prev)
681 struct device_node *next;
684 raw_spin_lock_irqsave(&devtree_lock, flags);
685 next = __of_get_next_child(node, prev);
686 raw_spin_unlock_irqrestore(&devtree_lock, flags);
689 EXPORT_SYMBOL(of_get_next_child);
692 * of_get_next_available_child - Find the next available child node
694 * @prev: previous child of the parent node, or NULL to get first
696 * This function is like of_get_next_child(), except that it
697 * automatically skips any disabled nodes (i.e. status = "disabled").
699 struct device_node *of_get_next_available_child(const struct device_node *node,
700 struct device_node *prev)
702 struct device_node *next;
708 raw_spin_lock_irqsave(&devtree_lock, flags);
709 next = prev ? prev->sibling : node->child;
710 for (; next; next = next->sibling) {
711 if (!__of_device_is_available(next))
713 if (of_node_get(next))
717 raw_spin_unlock_irqrestore(&devtree_lock, flags);
720 EXPORT_SYMBOL(of_get_next_available_child);
723 * of_get_child_by_name - Find the child node by name for a given parent
725 * @name: child name to look for.
727 * This function looks for child node for given matching name
729 * Returns a node pointer if found, with refcount incremented, use
730 * of_node_put() on it when done.
731 * Returns NULL if node is not found.
733 struct device_node *of_get_child_by_name(const struct device_node *node,
736 struct device_node *child;
738 for_each_child_of_node(node, child)
739 if (child->name && (of_node_cmp(child->name, name) == 0))
743 EXPORT_SYMBOL(of_get_child_by_name);
745 struct device_node *__of_find_node_by_path(struct device_node *parent,
748 struct device_node *child;
751 len = strcspn(path, "/:");
755 __for_each_child_of_node(parent, child) {
756 const char *name = kbasename(child->full_name);
757 if (strncmp(path, name, len) == 0 && (strlen(name) == len))
763 struct device_node *__of_find_node_by_full_path(struct device_node *node,
766 const char *separator = strchr(path, ':');
768 while (node && *path == '/') {
769 struct device_node *tmp = node;
771 path++; /* Increment past '/' delimiter */
772 node = __of_find_node_by_path(node, path);
774 path = strchrnul(path, '/');
775 if (separator && separator < path)
782 * of_find_node_opts_by_path - Find a node matching a full OF path
783 * @path: Either the full path to match, or if the path does not
784 * start with '/', the name of a property of the /aliases
785 * node (an alias). In the case of an alias, the node
786 * matching the alias' value will be returned.
787 * @opts: Address of a pointer into which to store the start of
788 * an options string appended to the end of the path with
794 * foo/bar Valid alias + relative path
796 * Returns a node pointer with refcount incremented, use
797 * of_node_put() on it when done.
799 struct device_node *of_find_node_opts_by_path(const char *path, const char **opts)
801 struct device_node *np = NULL;
804 const char *separator = strchr(path, ':');
807 *opts = separator ? separator + 1 : NULL;
809 if (strcmp(path, "/") == 0)
810 return of_node_get(of_root);
812 /* The path could begin with an alias */
815 const char *p = separator;
818 p = strchrnul(path, '/');
821 /* of_aliases must not be NULL */
825 for_each_property_of_node(of_aliases, pp) {
826 if (strlen(pp->name) == len && !strncmp(pp->name, path, len)) {
827 np = of_find_node_by_path(pp->value);
836 /* Step down the tree matching path components */
837 raw_spin_lock_irqsave(&devtree_lock, flags);
839 np = of_node_get(of_root);
840 np = __of_find_node_by_full_path(np, path);
841 raw_spin_unlock_irqrestore(&devtree_lock, flags);
844 EXPORT_SYMBOL(of_find_node_opts_by_path);
847 * of_find_node_by_name - Find a node by its "name" property
848 * @from: The node to start searching from or NULL; the node
849 * you pass will not be searched, only the next one
850 * will. Typically, you pass what the previous call
851 * returned. of_node_put() will be called on @from.
852 * @name: The name string to match against
854 * Returns a node pointer with refcount incremented, use
855 * of_node_put() on it when done.
857 struct device_node *of_find_node_by_name(struct device_node *from,
860 struct device_node *np;
863 raw_spin_lock_irqsave(&devtree_lock, flags);
864 for_each_of_allnodes_from(from, np)
865 if (np->name && (of_node_cmp(np->name, name) == 0)
869 raw_spin_unlock_irqrestore(&devtree_lock, flags);
872 EXPORT_SYMBOL(of_find_node_by_name);
875 * of_find_node_by_type - Find a node by its "device_type" property
876 * @from: The node to start searching from, or NULL to start searching
877 * the entire device tree. The node you pass will not be
878 * searched, only the next one will; typically, you pass
879 * what the previous call returned. of_node_put() will be
880 * called on from for you.
881 * @type: The type string to match against
883 * Returns a node pointer with refcount incremented, use
884 * of_node_put() on it when done.
886 struct device_node *of_find_node_by_type(struct device_node *from,
889 struct device_node *np;
892 raw_spin_lock_irqsave(&devtree_lock, flags);
893 for_each_of_allnodes_from(from, np)
894 if (np->type && (of_node_cmp(np->type, type) == 0)
898 raw_spin_unlock_irqrestore(&devtree_lock, flags);
901 EXPORT_SYMBOL(of_find_node_by_type);
904 * of_find_compatible_node - Find a node based on type and one of the
905 * tokens in its "compatible" property
906 * @from: The node to start searching from or NULL, the node
907 * you pass will not be searched, only the next one
908 * will; typically, you pass what the previous call
909 * returned. of_node_put() will be called on it
910 * @type: The type string to match "device_type" or NULL to ignore
911 * @compatible: The string to match to one of the tokens in the device
914 * Returns a node pointer with refcount incremented, use
915 * of_node_put() on it when done.
917 struct device_node *of_find_compatible_node(struct device_node *from,
918 const char *type, const char *compatible)
920 struct device_node *np;
923 raw_spin_lock_irqsave(&devtree_lock, flags);
924 for_each_of_allnodes_from(from, np)
925 if (__of_device_is_compatible(np, compatible, type, NULL) &&
929 raw_spin_unlock_irqrestore(&devtree_lock, flags);
932 EXPORT_SYMBOL(of_find_compatible_node);
935 * of_find_node_with_property - Find a node which has a property with
937 * @from: The node to start searching from or NULL, the node
938 * you pass will not be searched, only the next one
939 * will; typically, you pass what the previous call
940 * returned. of_node_put() will be called on it
941 * @prop_name: The name of the property to look for.
943 * Returns a node pointer with refcount incremented, use
944 * of_node_put() on it when done.
946 struct device_node *of_find_node_with_property(struct device_node *from,
947 const char *prop_name)
949 struct device_node *np;
953 raw_spin_lock_irqsave(&devtree_lock, flags);
954 for_each_of_allnodes_from(from, np) {
955 for (pp = np->properties; pp; pp = pp->next) {
956 if (of_prop_cmp(pp->name, prop_name) == 0) {
964 raw_spin_unlock_irqrestore(&devtree_lock, flags);
967 EXPORT_SYMBOL(of_find_node_with_property);
970 const struct of_device_id *__of_match_node(const struct of_device_id *matches,
971 const struct device_node *node)
973 const struct of_device_id *best_match = NULL;
974 int score, best_score = 0;
979 for (; matches->name[0] || matches->type[0] || matches->compatible[0]; matches++) {
980 score = __of_device_is_compatible(node, matches->compatible,
981 matches->type, matches->name);
982 if (score > best_score) {
983 best_match = matches;
992 * of_match_node - Tell if a device_node has a matching of_match structure
993 * @matches: array of of device match structures to search in
994 * @node: the of device structure to match against
996 * Low level utility function used by device matching.
998 const struct of_device_id *of_match_node(const struct of_device_id *matches,
999 const struct device_node *node)
1001 const struct of_device_id *match;
1002 unsigned long flags;
1004 raw_spin_lock_irqsave(&devtree_lock, flags);
1005 match = __of_match_node(matches, node);
1006 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1009 EXPORT_SYMBOL(of_match_node);
1012 * of_find_matching_node_and_match - Find a node based on an of_device_id
1014 * @from: The node to start searching from or NULL, the node
1015 * you pass will not be searched, only the next one
1016 * will; typically, you pass what the previous call
1017 * returned. of_node_put() will be called on it
1018 * @matches: array of of device match structures to search in
1019 * @match Updated to point at the matches entry which matched
1021 * Returns a node pointer with refcount incremented, use
1022 * of_node_put() on it when done.
1024 struct device_node *of_find_matching_node_and_match(struct device_node *from,
1025 const struct of_device_id *matches,
1026 const struct of_device_id **match)
1028 struct device_node *np;
1029 const struct of_device_id *m;
1030 unsigned long flags;
1035 raw_spin_lock_irqsave(&devtree_lock, flags);
1036 for_each_of_allnodes_from(from, np) {
1037 m = __of_match_node(matches, np);
1038 if (m && of_node_get(np)) {
1045 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1048 EXPORT_SYMBOL(of_find_matching_node_and_match);
1051 * of_modalias_node - Lookup appropriate modalias for a device node
1052 * @node: pointer to a device tree node
1053 * @modalias: Pointer to buffer that modalias value will be copied into
1054 * @len: Length of modalias value
1056 * Based on the value of the compatible property, this routine will attempt
1057 * to choose an appropriate modalias value for a particular device tree node.
1058 * It does this by stripping the manufacturer prefix (as delimited by a ',')
1059 * from the first entry in the compatible list property.
1061 * This routine returns 0 on success, <0 on failure.
1063 int of_modalias_node(struct device_node *node, char *modalias, int len)
1065 const char *compatible, *p;
1068 compatible = of_get_property(node, "compatible", &cplen);
1069 if (!compatible || strlen(compatible) > cplen)
1071 p = strchr(compatible, ',');
1072 strlcpy(modalias, p ? p + 1 : compatible, len);
1075 EXPORT_SYMBOL_GPL(of_modalias_node);
1078 * of_find_node_by_phandle - Find a node given a phandle
1079 * @handle: phandle of the node to find
1081 * Returns a node pointer with refcount incremented, use
1082 * of_node_put() on it when done.
1084 struct device_node *of_find_node_by_phandle(phandle handle)
1086 struct device_node *np = NULL;
1087 unsigned long flags;
1088 phandle masked_handle;
1093 raw_spin_lock_irqsave(&devtree_lock, flags);
1095 masked_handle = handle & phandle_cache_mask;
1097 if (phandle_cache) {
1098 if (phandle_cache[masked_handle] &&
1099 handle == phandle_cache[masked_handle]->phandle)
1100 np = phandle_cache[masked_handle];
1104 for_each_of_allnodes(np)
1105 if (np->phandle == handle) {
1107 phandle_cache[masked_handle] = np;
1113 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1116 EXPORT_SYMBOL(of_find_node_by_phandle);
1118 void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
1121 printk("%s %pOF", msg, args->np);
1122 for (i = 0; i < args->args_count; i++) {
1123 const char delim = i ? ',' : ':';
1125 pr_cont("%c%08x", delim, args->args[i]);
1130 int of_phandle_iterator_init(struct of_phandle_iterator *it,
1131 const struct device_node *np,
1132 const char *list_name,
1133 const char *cells_name,
1139 memset(it, 0, sizeof(*it));
1141 list = of_get_property(np, list_name, &size);
1145 it->cells_name = cells_name;
1146 it->cell_count = cell_count;
1148 it->list_end = list + size / sizeof(*list);
1149 it->phandle_end = list;
1154 EXPORT_SYMBOL_GPL(of_phandle_iterator_init);
1156 int of_phandle_iterator_next(struct of_phandle_iterator *it)
1161 of_node_put(it->node);
1165 if (!it->cur || it->phandle_end >= it->list_end)
1168 it->cur = it->phandle_end;
1170 /* If phandle is 0, then it is an empty entry with no arguments. */
1171 it->phandle = be32_to_cpup(it->cur++);
1176 * Find the provider node and parse the #*-cells property to
1177 * determine the argument length.
1179 it->node = of_find_node_by_phandle(it->phandle);
1181 if (it->cells_name) {
1183 pr_err("%pOF: could not find phandle\n",
1188 if (of_property_read_u32(it->node, it->cells_name,
1190 pr_err("%pOF: could not get %s for %pOF\n",
1197 count = it->cell_count;
1201 * Make sure that the arguments actually fit in the remaining
1202 * property data length
1204 if (it->cur + count > it->list_end) {
1205 pr_err("%pOF: arguments longer than property\n",
1211 it->phandle_end = it->cur + count;
1212 it->cur_count = count;
1218 of_node_put(it->node);
1224 EXPORT_SYMBOL_GPL(of_phandle_iterator_next);
1226 int of_phandle_iterator_args(struct of_phandle_iterator *it,
1232 count = it->cur_count;
1234 if (WARN_ON(size < count))
1237 for (i = 0; i < count; i++)
1238 args[i] = be32_to_cpup(it->cur++);
1243 static int __of_parse_phandle_with_args(const struct device_node *np,
1244 const char *list_name,
1245 const char *cells_name,
1246 int cell_count, int index,
1247 struct of_phandle_args *out_args)
1249 struct of_phandle_iterator it;
1250 int rc, cur_index = 0;
1252 /* Loop over the phandles until all the requested entry is found */
1253 of_for_each_phandle(&it, rc, np, list_name, cells_name, cell_count) {
1255 * All of the error cases bail out of the loop, so at
1256 * this point, the parsing is successful. If the requested
1257 * index matches, then fill the out_args structure and return,
1258 * or return -ENOENT for an empty entry.
1261 if (cur_index == index) {
1268 c = of_phandle_iterator_args(&it,
1271 out_args->np = it.node;
1272 out_args->args_count = c;
1274 of_node_put(it.node);
1277 /* Found it! return success */
1285 * Unlock node before returning result; will be one of:
1286 * -ENOENT : index is for empty phandle
1287 * -EINVAL : parsing error on data
1291 of_node_put(it.node);
1296 * of_parse_phandle - Resolve a phandle property to a device_node pointer
1297 * @np: Pointer to device node holding phandle property
1298 * @phandle_name: Name of property holding a phandle value
1299 * @index: For properties holding a table of phandles, this is the index into
1302 * Returns the device_node pointer with refcount incremented. Use
1303 * of_node_put() on it when done.
1305 struct device_node *of_parse_phandle(const struct device_node *np,
1306 const char *phandle_name, int index)
1308 struct of_phandle_args args;
1313 if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0,
1319 EXPORT_SYMBOL(of_parse_phandle);
1322 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
1323 * @np: pointer to a device tree node containing a list
1324 * @list_name: property name that contains a list
1325 * @cells_name: property name that specifies phandles' arguments count
1326 * @index: index of a phandle to parse out
1327 * @out_args: optional pointer to output arguments structure (will be filled)
1329 * This function is useful to parse lists of phandles and their arguments.
1330 * Returns 0 on success and fills out_args, on error returns appropriate
1333 * Caller is responsible to call of_node_put() on the returned out_args->np
1339 * #list-cells = <2>;
1343 * #list-cells = <1>;
1347 * list = <&phandle1 1 2 &phandle2 3>;
1350 * To get a device_node of the `node2' node you may call this:
1351 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
1353 int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
1354 const char *cells_name, int index,
1355 struct of_phandle_args *out_args)
1359 return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
1362 EXPORT_SYMBOL(of_parse_phandle_with_args);
1365 * of_parse_phandle_with_args_map() - Find a node pointed by phandle in a list and remap it
1366 * @np: pointer to a device tree node containing a list
1367 * @list_name: property name that contains a list
1368 * @stem_name: stem of property names that specify phandles' arguments count
1369 * @index: index of a phandle to parse out
1370 * @out_args: optional pointer to output arguments structure (will be filled)
1372 * This function is useful to parse lists of phandles and their arguments.
1373 * Returns 0 on success and fills out_args, on error returns appropriate errno
1374 * value. The difference between this function and of_parse_phandle_with_args()
1375 * is that this API remaps a phandle if the node the phandle points to has
1376 * a <@stem_name>-map property.
1378 * Caller is responsible to call of_node_put() on the returned out_args->np
1384 * #list-cells = <2>;
1388 * #list-cells = <1>;
1392 * #list-cells = <1>;
1393 * list-map = <0 &phandle2 3>,
1395 * <2 &phandle1 5 1>;
1396 * list-map-mask = <0x3>;
1400 * list = <&phandle1 1 2 &phandle3 0>;
1403 * To get a device_node of the `node2' node you may call this:
1404 * of_parse_phandle_with_args(node4, "list", "list", 1, &args);
1406 int of_parse_phandle_with_args_map(const struct device_node *np,
1407 const char *list_name,
1408 const char *stem_name,
1409 int index, struct of_phandle_args *out_args)
1411 char *cells_name, *map_name = NULL, *mask_name = NULL;
1412 char *pass_name = NULL;
1413 struct device_node *cur, *new = NULL;
1414 const __be32 *map, *mask, *pass;
1415 static const __be32 dummy_mask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
1416 static const __be32 dummy_pass[] = { [0 ... MAX_PHANDLE_ARGS] = 0 };
1417 __be32 initial_match_array[MAX_PHANDLE_ARGS];
1418 const __be32 *match_array = initial_match_array;
1419 int i, ret, map_len, match;
1420 u32 list_size, new_size;
1425 cells_name = kasprintf(GFP_KERNEL, "#%s-cells", stem_name);
1430 map_name = kasprintf(GFP_KERNEL, "%s-map", stem_name);
1434 mask_name = kasprintf(GFP_KERNEL, "%s-map-mask", stem_name);
1438 pass_name = kasprintf(GFP_KERNEL, "%s-map-pass-thru", stem_name);
1442 ret = __of_parse_phandle_with_args(np, list_name, cells_name, 0, index,
1447 /* Get the #<list>-cells property */
1449 ret = of_property_read_u32(cur, cells_name, &list_size);
1453 /* Precalculate the match array - this simplifies match loop */
1454 for (i = 0; i < list_size; i++)
1455 initial_match_array[i] = cpu_to_be32(out_args->args[i]);
1459 /* Get the <list>-map property */
1460 map = of_get_property(cur, map_name, &map_len);
1465 map_len /= sizeof(u32);
1467 /* Get the <list>-map-mask property (optional) */
1468 mask = of_get_property(cur, mask_name, NULL);
1471 /* Iterate through <list>-map property */
1473 while (map_len > (list_size + 1) && !match) {
1474 /* Compare specifiers */
1476 for (i = 0; i < list_size; i++, map_len--)
1477 match &= !((match_array[i] ^ *map++) & mask[i]);
1480 new = of_find_node_by_phandle(be32_to_cpup(map));
1484 /* Check if not found */
1488 if (!of_device_is_available(new))
1491 ret = of_property_read_u32(new, cells_name, &new_size);
1495 /* Check for malformed properties */
1496 if (WARN_ON(new_size > MAX_PHANDLE_ARGS))
1498 if (map_len < new_size)
1501 /* Move forward by new node's #<list>-cells amount */
1503 map_len -= new_size;
1508 /* Get the <list>-map-pass-thru property (optional) */
1509 pass = of_get_property(cur, pass_name, NULL);
1514 * Successfully parsed a <list>-map translation; copy new
1515 * specifier into the out_args structure, keeping the
1516 * bits specified in <list>-map-pass-thru.
1518 match_array = map - new_size;
1519 for (i = 0; i < new_size; i++) {
1520 __be32 val = *(map - new_size + i);
1522 if (i < list_size) {
1524 val |= cpu_to_be32(out_args->args[i]) & pass[i];
1527 out_args->args[i] = be32_to_cpu(val);
1529 out_args->args_count = list_size = new_size;
1530 /* Iterate again with new provider */
1546 EXPORT_SYMBOL(of_parse_phandle_with_args_map);
1549 * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
1550 * @np: pointer to a device tree node containing a list
1551 * @list_name: property name that contains a list
1552 * @cell_count: number of argument cells following the phandle
1553 * @index: index of a phandle to parse out
1554 * @out_args: optional pointer to output arguments structure (will be filled)
1556 * This function is useful to parse lists of phandles and their arguments.
1557 * Returns 0 on success and fills out_args, on error returns appropriate
1560 * Caller is responsible to call of_node_put() on the returned out_args->np
1572 * list = <&phandle1 0 2 &phandle2 2 3>;
1575 * To get a device_node of the `node2' node you may call this:
1576 * of_parse_phandle_with_fixed_args(node3, "list", 2, 1, &args);
1578 int of_parse_phandle_with_fixed_args(const struct device_node *np,
1579 const char *list_name, int cell_count,
1580 int index, struct of_phandle_args *out_args)
1584 return __of_parse_phandle_with_args(np, list_name, NULL, cell_count,
1587 EXPORT_SYMBOL(of_parse_phandle_with_fixed_args);
1590 * of_count_phandle_with_args() - Find the number of phandles references in a property
1591 * @np: pointer to a device tree node containing a list
1592 * @list_name: property name that contains a list
1593 * @cells_name: property name that specifies phandles' arguments count
1595 * Returns the number of phandle + argument tuples within a property. It
1596 * is a typical pattern to encode a list of phandle and variable
1597 * arguments into a single property. The number of arguments is encoded
1598 * by a property in the phandle-target node. For example, a gpios
1599 * property would contain a list of GPIO specifies consisting of a
1600 * phandle and 1 or more arguments. The number of arguments are
1601 * determined by the #gpio-cells property in the node pointed to by the
1604 int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
1605 const char *cells_name)
1607 struct of_phandle_iterator it;
1608 int rc, cur_index = 0;
1610 rc = of_phandle_iterator_init(&it, np, list_name, cells_name, 0);
1614 while ((rc = of_phandle_iterator_next(&it)) == 0)
1622 EXPORT_SYMBOL(of_count_phandle_with_args);
1625 * __of_add_property - Add a property to a node without lock operations
1627 int __of_add_property(struct device_node *np, struct property *prop)
1629 struct property **next;
1632 next = &np->properties;
1634 if (strcmp(prop->name, (*next)->name) == 0)
1635 /* duplicate ! don't insert it */
1638 next = &(*next)->next;
1646 * of_add_property - Add a property to a node
1648 int of_add_property(struct device_node *np, struct property *prop)
1650 unsigned long flags;
1653 mutex_lock(&of_mutex);
1655 raw_spin_lock_irqsave(&devtree_lock, flags);
1656 rc = __of_add_property(np, prop);
1657 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1660 __of_add_property_sysfs(np, prop);
1662 mutex_unlock(&of_mutex);
1665 of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop, NULL);
1670 int __of_remove_property(struct device_node *np, struct property *prop)
1672 struct property **next;
1674 for (next = &np->properties; *next; next = &(*next)->next) {
1681 /* found the node */
1683 prop->next = np->deadprops;
1684 np->deadprops = prop;
1690 * of_remove_property - Remove a property from a node.
1692 * Note that we don't actually remove it, since we have given out
1693 * who-knows-how-many pointers to the data using get-property.
1694 * Instead we just move the property to the "dead properties"
1695 * list, so it won't be found any more.
1697 int of_remove_property(struct device_node *np, struct property *prop)
1699 unsigned long flags;
1705 mutex_lock(&of_mutex);
1707 raw_spin_lock_irqsave(&devtree_lock, flags);
1708 rc = __of_remove_property(np, prop);
1709 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1712 __of_remove_property_sysfs(np, prop);
1714 mutex_unlock(&of_mutex);
1717 of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop, NULL);
1722 int __of_update_property(struct device_node *np, struct property *newprop,
1723 struct property **oldpropp)
1725 struct property **next, *oldprop;
1727 for (next = &np->properties; *next; next = &(*next)->next) {
1728 if (of_prop_cmp((*next)->name, newprop->name) == 0)
1731 *oldpropp = oldprop = *next;
1734 /* replace the node */
1735 newprop->next = oldprop->next;
1737 oldprop->next = np->deadprops;
1738 np->deadprops = oldprop;
1741 newprop->next = NULL;
1749 * of_update_property - Update a property in a node, if the property does
1750 * not exist, add it.
1752 * Note that we don't actually remove it, since we have given out
1753 * who-knows-how-many pointers to the data using get-property.
1754 * Instead we just move the property to the "dead properties" list,
1755 * and add the new property to the property list
1757 int of_update_property(struct device_node *np, struct property *newprop)
1759 struct property *oldprop;
1760 unsigned long flags;
1766 mutex_lock(&of_mutex);
1768 raw_spin_lock_irqsave(&devtree_lock, flags);
1769 rc = __of_update_property(np, newprop, &oldprop);
1770 raw_spin_unlock_irqrestore(&devtree_lock, flags);
1773 __of_update_property_sysfs(np, newprop, oldprop);
1775 mutex_unlock(&of_mutex);
1778 of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop, oldprop);
1783 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1784 int id, const char *stem, int stem_len)
1788 strncpy(ap->stem, stem, stem_len);
1789 ap->stem[stem_len] = 0;
1790 list_add_tail(&ap->link, &aliases_lookup);
1791 pr_debug("adding DT alias:%s: stem=%s id=%i node=%pOF\n",
1792 ap->alias, ap->stem, ap->id, np);
1796 * of_alias_scan - Scan all properties of the 'aliases' node
1798 * The function scans all the properties of the 'aliases' node and populates
1799 * the global lookup table with the properties. It returns the
1800 * number of alias properties found, or an error code in case of failure.
1802 * @dt_alloc: An allocator that provides a virtual address to memory
1803 * for storing the resulting tree
1805 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1807 struct property *pp;
1809 of_aliases = of_find_node_by_path("/aliases");
1810 of_chosen = of_find_node_by_path("/chosen");
1811 if (of_chosen == NULL)
1812 of_chosen = of_find_node_by_path("/chosen@0");
1815 /* linux,stdout-path and /aliases/stdout are for legacy compatibility */
1816 const char *name = NULL;
1818 if (of_property_read_string(of_chosen, "stdout-path", &name))
1819 of_property_read_string(of_chosen, "linux,stdout-path",
1821 if (IS_ENABLED(CONFIG_PPC) && !name)
1822 of_property_read_string(of_aliases, "stdout", &name);
1824 of_stdout = of_find_node_opts_by_path(name, &of_stdout_options);
1830 for_each_property_of_node(of_aliases, pp) {
1831 const char *start = pp->name;
1832 const char *end = start + strlen(start);
1833 struct device_node *np;
1834 struct alias_prop *ap;
1837 /* Skip those we do not want to proceed */
1838 if (!strcmp(pp->name, "name") ||
1839 !strcmp(pp->name, "phandle") ||
1840 !strcmp(pp->name, "linux,phandle"))
1843 np = of_find_node_by_path(pp->value);
1847 /* walk the alias backwards to extract the id and work out
1848 * the 'stem' string */
1849 while (isdigit(*(end-1)) && end > start)
1853 if (kstrtoint(end, 10, &id) < 0)
1856 /* Allocate an alias_prop with enough space for the stem */
1857 ap = dt_alloc(sizeof(*ap) + len + 1, __alignof__(*ap));
1860 memset(ap, 0, sizeof(*ap) + len + 1);
1862 of_alias_add(ap, np, id, start, len);
1867 * of_alias_get_id - Get alias id for the given device_node
1868 * @np: Pointer to the given device_node
1869 * @stem: Alias stem of the given device_node
1871 * The function travels the lookup table to get the alias id for the given
1872 * device_node and alias stem. It returns the alias id if found.
1874 int of_alias_get_id(struct device_node *np, const char *stem)
1876 struct alias_prop *app;
1879 mutex_lock(&of_mutex);
1880 list_for_each_entry(app, &aliases_lookup, link) {
1881 if (strcmp(app->stem, stem) != 0)
1884 if (np == app->np) {
1889 mutex_unlock(&of_mutex);
1893 EXPORT_SYMBOL_GPL(of_alias_get_id);
1896 * of_alias_get_highest_id - Get highest alias id for the given stem
1897 * @stem: Alias stem to be examined
1899 * The function travels the lookup table to get the highest alias id for the
1900 * given alias stem. It returns the alias id if found.
1902 int of_alias_get_highest_id(const char *stem)
1904 struct alias_prop *app;
1907 mutex_lock(&of_mutex);
1908 list_for_each_entry(app, &aliases_lookup, link) {
1909 if (strcmp(app->stem, stem) != 0)
1915 mutex_unlock(&of_mutex);
1919 EXPORT_SYMBOL_GPL(of_alias_get_highest_id);
1922 * of_console_check() - Test and setup console for DT setup
1923 * @dn - Pointer to device node
1924 * @name - Name to use for preferred console without index. ex. "ttyS"
1925 * @index - Index to use for preferred console.
1927 * Check if the given device node matches the stdout-path property in the
1928 * /chosen node. If it does then register it as the preferred console and return
1929 * TRUE. Otherwise return FALSE.
1931 bool of_console_check(struct device_node *dn, char *name, int index)
1933 if (!dn || dn != of_stdout || console_set_on_cmdline)
1937 * XXX: cast `options' to char pointer to suppress complication
1938 * warnings: printk, UART and console drivers expect char pointer.
1940 return !add_preferred_console(name, index, (char *)of_stdout_options);
1942 EXPORT_SYMBOL_GPL(of_console_check);
1945 * of_find_next_cache_node - Find a node's subsidiary cache
1946 * @np: node of type "cpu" or "cache"
1948 * Returns a node pointer with refcount incremented, use
1949 * of_node_put() on it when done. Caller should hold a reference
1952 struct device_node *of_find_next_cache_node(const struct device_node *np)
1954 struct device_node *child, *cache_node;
1956 cache_node = of_parse_phandle(np, "l2-cache", 0);
1958 cache_node = of_parse_phandle(np, "next-level-cache", 0);
1963 /* OF on pmac has nodes instead of properties named "l2-cache"
1964 * beneath CPU nodes.
1966 if (!strcmp(np->type, "cpu"))
1967 for_each_child_of_node(np, child)
1968 if (!strcmp(child->type, "cache"))
1975 * of_find_last_cache_level - Find the level at which the last cache is
1976 * present for the given logical cpu
1978 * @cpu: cpu number(logical index) for which the last cache level is needed
1980 * Returns the the level at which the last cache is present. It is exactly
1981 * same as the total number of cache levels for the given logical cpu.
1983 int of_find_last_cache_level(unsigned int cpu)
1985 u32 cache_level = 0;
1986 struct device_node *prev = NULL, *np = of_cpu_device_node_get(cpu);
1991 np = of_find_next_cache_node(np);
1994 of_property_read_u32(prev, "cache-level", &cache_level);