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1/*
2 * Procedures for creating, accessing and interpreting the device tree.
3 *
4 * Paul Mackerras August 1996.
5 * Copyright (C) 1996-2005 Paul Mackerras.
6 *
7 * Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
8 * {engebret|bergner}@us.ibm.com
9 *
10 * Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
11 *
12 * Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
13 * Grant Likely.
14 *
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.
19 */
20#include <linux/ctype.h>
21#include <linux/module.h>
22#include <linux/of.h>
23#include <linux/spinlock.h>
24#include <linux/slab.h>
25#include <linux/proc_fs.h>
26
27/**
28 * struct alias_prop - Alias property in 'aliases' node
29 * @link: List node to link the structure in aliases_lookup list
30 * @alias: Alias property name
31 * @np: Pointer to device_node that the alias stands for
32 * @id: Index value from end of alias name
33 * @stem: Alias string without the index
34 *
35 * The structure represents one alias property of 'aliases' node as
36 * an entry in aliases_lookup list.
37 */
38struct alias_prop {
39 struct list_head link;
40 const char *alias;
41 struct device_node *np;
42 int id;
43 char stem[0];
44};
45
46static LIST_HEAD(aliases_lookup);
47
48struct device_node *allnodes;
49struct device_node *of_chosen;
50struct device_node *of_aliases;
51
52static DEFINE_MUTEX(of_aliases_mutex);
53
54/* use when traversing tree through the allnext, child, sibling,
55 * or parent members of struct device_node.
56 */
57DEFINE_RWLOCK(devtree_lock);
58
59int of_n_addr_cells(struct device_node *np)
60{
61 const __be32 *ip;
62
63 do {
64 if (np->parent)
65 np = np->parent;
66 ip = of_get_property(np, "#address-cells", NULL);
67 if (ip)
68 return be32_to_cpup(ip);
69 } while (np->parent);
70 /* No #address-cells property for the root node */
71 return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
72}
73EXPORT_SYMBOL(of_n_addr_cells);
74
75int of_n_size_cells(struct device_node *np)
76{
77 const __be32 *ip;
78
79 do {
80 if (np->parent)
81 np = np->parent;
82 ip = of_get_property(np, "#size-cells", NULL);
83 if (ip)
84 return be32_to_cpup(ip);
85 } while (np->parent);
86 /* No #size-cells property for the root node */
87 return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
88}
89EXPORT_SYMBOL(of_n_size_cells);
90
91#if defined(CONFIG_OF_DYNAMIC)
92/**
93 * of_node_get - Increment refcount of a node
94 * @node: Node to inc refcount, NULL is supported to
95 * simplify writing of callers
96 *
97 * Returns node.
98 */
99struct device_node *of_node_get(struct device_node *node)
100{
101 if (node)
102 kref_get(&node->kref);
103 return node;
104}
105EXPORT_SYMBOL(of_node_get);
106
107static inline struct device_node *kref_to_device_node(struct kref *kref)
108{
109 return container_of(kref, struct device_node, kref);
110}
111
112/**
113 * of_node_release - release a dynamically allocated node
114 * @kref: kref element of the node to be released
115 *
116 * In of_node_put() this function is passed to kref_put()
117 * as the destructor.
118 */
119static void of_node_release(struct kref *kref)
120{
121 struct device_node *node = kref_to_device_node(kref);
122 struct property *prop = node->properties;
123
124 /* We should never be releasing nodes that haven't been detached. */
125 if (!of_node_check_flag(node, OF_DETACHED)) {
126 pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name);
127 dump_stack();
128 kref_init(&node->kref);
129 return;
130 }
131
132 if (!of_node_check_flag(node, OF_DYNAMIC))
133 return;
134
135 while (prop) {
136 struct property *next = prop->next;
137 kfree(prop->name);
138 kfree(prop->value);
139 kfree(prop);
140 prop = next;
141
142 if (!prop) {
143 prop = node->deadprops;
144 node->deadprops = NULL;
145 }
146 }
147 kfree(node->full_name);
148 kfree(node->data);
149 kfree(node);
150}
151
152/**
153 * of_node_put - Decrement refcount of a node
154 * @node: Node to dec refcount, NULL is supported to
155 * simplify writing of callers
156 *
157 */
158void of_node_put(struct device_node *node)
159{
160 if (node)
161 kref_put(&node->kref, of_node_release);
162}
163EXPORT_SYMBOL(of_node_put);
164#endif /* CONFIG_OF_DYNAMIC */
165
166struct property *of_find_property(const struct device_node *np,
167 const char *name,
168 int *lenp)
169{
170 struct property *pp;
171
172 if (!np)
173 return NULL;
174
175 read_lock(&devtree_lock);
176 for (pp = np->properties; pp != 0; pp = pp->next) {
177 if (of_prop_cmp(pp->name, name) == 0) {
178 if (lenp != 0)
179 *lenp = pp->length;
180 break;
181 }
182 }
183 read_unlock(&devtree_lock);
184
185 return pp;
186}
187EXPORT_SYMBOL(of_find_property);
188
189/**
190 * of_find_all_nodes - Get next node in global list
191 * @prev: Previous node or NULL to start iteration
192 * of_node_put() will be called on it
193 *
194 * Returns a node pointer with refcount incremented, use
195 * of_node_put() on it when done.
196 */
197struct device_node *of_find_all_nodes(struct device_node *prev)
198{
199 struct device_node *np;
200
201 read_lock(&devtree_lock);
202 np = prev ? prev->allnext : allnodes;
203 for (; np != NULL; np = np->allnext)
204 if (of_node_get(np))
205 break;
206 of_node_put(prev);
207 read_unlock(&devtree_lock);
208 return np;
209}
210EXPORT_SYMBOL(of_find_all_nodes);
211
212/*
213 * Find a property with a given name for a given node
214 * and return the value.
215 */
216const void *of_get_property(const struct device_node *np, const char *name,
217 int *lenp)
218{
219 struct property *pp = of_find_property(np, name, lenp);
220
221 return pp ? pp->value : NULL;
222}
223EXPORT_SYMBOL(of_get_property);
224
225/** Checks if the given "compat" string matches one of the strings in
226 * the device's "compatible" property
227 */
228int of_device_is_compatible(const struct device_node *device,
229 const char *compat)
230{
231 const char* cp;
232 int cplen, l;
233
234 cp = of_get_property(device, "compatible", &cplen);
235 if (cp == NULL)
236 return 0;
237 while (cplen > 0) {
238 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
239 return 1;
240 l = strlen(cp) + 1;
241 cp += l;
242 cplen -= l;
243 }
244
245 return 0;
246}
247EXPORT_SYMBOL(of_device_is_compatible);
248
249/**
250 * of_machine_is_compatible - Test root of device tree for a given compatible value
251 * @compat: compatible string to look for in root node's compatible property.
252 *
253 * Returns true if the root node has the given value in its
254 * compatible property.
255 */
256int of_machine_is_compatible(const char *compat)
257{
258 struct device_node *root;
259 int rc = 0;
260
261 root = of_find_node_by_path("/");
262 if (root) {
263 rc = of_device_is_compatible(root, compat);
264 of_node_put(root);
265 }
266 return rc;
267}
268EXPORT_SYMBOL(of_machine_is_compatible);
269
270/**
271 * of_device_is_available - check if a device is available for use
272 *
273 * @device: Node to check for availability
274 *
275 * Returns 1 if the status property is absent or set to "okay" or "ok",
276 * 0 otherwise
277 */
278int of_device_is_available(const struct device_node *device)
279{
280 const char *status;
281 int statlen;
282
283 status = of_get_property(device, "status", &statlen);
284 if (status == NULL)
285 return 1;
286
287 if (statlen > 0) {
288 if (!strcmp(status, "okay") || !strcmp(status, "ok"))
289 return 1;
290 }
291
292 return 0;
293}
294EXPORT_SYMBOL(of_device_is_available);
295
296/**
297 * of_get_parent - Get a node's parent if any
298 * @node: Node to get parent
299 *
300 * Returns a node pointer with refcount incremented, use
301 * of_node_put() on it when done.
302 */
303struct device_node *of_get_parent(const struct device_node *node)
304{
305 struct device_node *np;
306
307 if (!node)
308 return NULL;
309
310 read_lock(&devtree_lock);
311 np = of_node_get(node->parent);
312 read_unlock(&devtree_lock);
313 return np;
314}
315EXPORT_SYMBOL(of_get_parent);
316
317/**
318 * of_get_next_parent - Iterate to a node's parent
319 * @node: Node to get parent of
320 *
321 * This is like of_get_parent() except that it drops the
322 * refcount on the passed node, making it suitable for iterating
323 * through a node's parents.
324 *
325 * Returns a node pointer with refcount incremented, use
326 * of_node_put() on it when done.
327 */
328struct device_node *of_get_next_parent(struct device_node *node)
329{
330 struct device_node *parent;
331
332 if (!node)
333 return NULL;
334
335 read_lock(&devtree_lock);
336 parent = of_node_get(node->parent);
337 of_node_put(node);
338 read_unlock(&devtree_lock);
339 return parent;
340}
341
342/**
343 * of_get_next_child - Iterate a node childs
344 * @node: parent node
345 * @prev: previous child of the parent node, or NULL to get first
346 *
347 * Returns a node pointer with refcount incremented, use
348 * of_node_put() on it when done.
349 */
350struct device_node *of_get_next_child(const struct device_node *node,
351 struct device_node *prev)
352{
353 struct device_node *next;
354
355 read_lock(&devtree_lock);
356 next = prev ? prev->sibling : node->child;
357 for (; next; next = next->sibling)
358 if (of_node_get(next))
359 break;
360 of_node_put(prev);
361 read_unlock(&devtree_lock);
362 return next;
363}
364EXPORT_SYMBOL(of_get_next_child);
365
366/**
367 * of_find_node_by_path - Find a node matching a full OF path
368 * @path: The full path to match
369 *
370 * Returns a node pointer with refcount incremented, use
371 * of_node_put() on it when done.
372 */
373struct device_node *of_find_node_by_path(const char *path)
374{
375 struct device_node *np = allnodes;
376
377 read_lock(&devtree_lock);
378 for (; np; np = np->allnext) {
379 if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
380 && of_node_get(np))
381 break;
382 }
383 read_unlock(&devtree_lock);
384 return np;
385}
386EXPORT_SYMBOL(of_find_node_by_path);
387
388/**
389 * of_find_node_by_name - Find a node by its "name" property
390 * @from: The node to start searching from or NULL, the node
391 * you pass will not be searched, only the next one
392 * will; typically, you pass what the previous call
393 * returned. of_node_put() will be called on it
394 * @name: The name string to match against
395 *
396 * Returns a node pointer with refcount incremented, use
397 * of_node_put() on it when done.
398 */
399struct device_node *of_find_node_by_name(struct device_node *from,
400 const char *name)
401{
402 struct device_node *np;
403
404 read_lock(&devtree_lock);
405 np = from ? from->allnext : allnodes;
406 for (; np; np = np->allnext)
407 if (np->name && (of_node_cmp(np->name, name) == 0)
408 && of_node_get(np))
409 break;
410 of_node_put(from);
411 read_unlock(&devtree_lock);
412 return np;
413}
414EXPORT_SYMBOL(of_find_node_by_name);
415
416/**
417 * of_find_node_by_type - Find a node by its "device_type" property
418 * @from: The node to start searching from, or NULL to start searching
419 * the entire device tree. The node you pass will not be
420 * searched, only the next one will; typically, you pass
421 * what the previous call returned. of_node_put() will be
422 * called on from for you.
423 * @type: The type string to match against
424 *
425 * Returns a node pointer with refcount incremented, use
426 * of_node_put() on it when done.
427 */
428struct device_node *of_find_node_by_type(struct device_node *from,
429 const char *type)
430{
431 struct device_node *np;
432
433 read_lock(&devtree_lock);
434 np = from ? from->allnext : allnodes;
435 for (; np; np = np->allnext)
436 if (np->type && (of_node_cmp(np->type, type) == 0)
437 && of_node_get(np))
438 break;
439 of_node_put(from);
440 read_unlock(&devtree_lock);
441 return np;
442}
443EXPORT_SYMBOL(of_find_node_by_type);
444
445/**
446 * of_find_compatible_node - Find a node based on type and one of the
447 * tokens in its "compatible" property
448 * @from: The node to start searching from or NULL, the node
449 * you pass will not be searched, only the next one
450 * will; typically, you pass what the previous call
451 * returned. of_node_put() will be called on it
452 * @type: The type string to match "device_type" or NULL to ignore
453 * @compatible: The string to match to one of the tokens in the device
454 * "compatible" list.
455 *
456 * Returns a node pointer with refcount incremented, use
457 * of_node_put() on it when done.
458 */
459struct device_node *of_find_compatible_node(struct device_node *from,
460 const char *type, const char *compatible)
461{
462 struct device_node *np;
463
464 read_lock(&devtree_lock);
465 np = from ? from->allnext : allnodes;
466 for (; np; np = np->allnext) {
467 if (type
468 && !(np->type && (of_node_cmp(np->type, type) == 0)))
469 continue;
470 if (of_device_is_compatible(np, compatible) && of_node_get(np))
471 break;
472 }
473 of_node_put(from);
474 read_unlock(&devtree_lock);
475 return np;
476}
477EXPORT_SYMBOL(of_find_compatible_node);
478
479/**
480 * of_find_node_with_property - Find a node which has a property with
481 * the given name.
482 * @from: The node to start searching from or NULL, the node
483 * you pass will not be searched, only the next one
484 * will; typically, you pass what the previous call
485 * returned. of_node_put() will be called on it
486 * @prop_name: The name of the property to look for.
487 *
488 * Returns a node pointer with refcount incremented, use
489 * of_node_put() on it when done.
490 */
491struct device_node *of_find_node_with_property(struct device_node *from,
492 const char *prop_name)
493{
494 struct device_node *np;
495 struct property *pp;
496
497 read_lock(&devtree_lock);
498 np = from ? from->allnext : allnodes;
499 for (; np; np = np->allnext) {
500 for (pp = np->properties; pp != 0; pp = pp->next) {
501 if (of_prop_cmp(pp->name, prop_name) == 0) {
502 of_node_get(np);
503 goto out;
504 }
505 }
506 }
507out:
508 of_node_put(from);
509 read_unlock(&devtree_lock);
510 return np;
511}
512EXPORT_SYMBOL(of_find_node_with_property);
513
514/**
515 * of_match_node - Tell if an device_node has a matching of_match structure
516 * @matches: array of of device match structures to search in
517 * @node: the of device structure to match against
518 *
519 * Low level utility function used by device matching.
520 */
521const struct of_device_id *of_match_node(const struct of_device_id *matches,
522 const struct device_node *node)
523{
524 if (!matches)
525 return NULL;
526
527 while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
528 int match = 1;
529 if (matches->name[0])
530 match &= node->name
531 && !strcmp(matches->name, node->name);
532 if (matches->type[0])
533 match &= node->type
534 && !strcmp(matches->type, node->type);
535 if (matches->compatible[0])
536 match &= of_device_is_compatible(node,
537 matches->compatible);
538 if (match)
539 return matches;
540 matches++;
541 }
542 return NULL;
543}
544EXPORT_SYMBOL(of_match_node);
545
546/**
547 * of_find_matching_node - Find a node based on an of_device_id match
548 * table.
549 * @from: The node to start searching from or NULL, the node
550 * you pass will not be searched, only the next one
551 * will; typically, you pass what the previous call
552 * returned. of_node_put() will be called on it
553 * @matches: array of of device match structures to search in
554 *
555 * Returns a node pointer with refcount incremented, use
556 * of_node_put() on it when done.
557 */
558struct device_node *of_find_matching_node(struct device_node *from,
559 const struct of_device_id *matches)
560{
561 struct device_node *np;
562
563 read_lock(&devtree_lock);
564 np = from ? from->allnext : allnodes;
565 for (; np; np = np->allnext) {
566 if (of_match_node(matches, np) && of_node_get(np))
567 break;
568 }
569 of_node_put(from);
570 read_unlock(&devtree_lock);
571 return np;
572}
573EXPORT_SYMBOL(of_find_matching_node);
574
575/**
576 * of_modalias_node - Lookup appropriate modalias for a device node
577 * @node: pointer to a device tree node
578 * @modalias: Pointer to buffer that modalias value will be copied into
579 * @len: Length of modalias value
580 *
581 * Based on the value of the compatible property, this routine will attempt
582 * to choose an appropriate modalias value for a particular device tree node.
583 * It does this by stripping the manufacturer prefix (as delimited by a ',')
584 * from the first entry in the compatible list property.
585 *
586 * This routine returns 0 on success, <0 on failure.
587 */
588int of_modalias_node(struct device_node *node, char *modalias, int len)
589{
590 const char *compatible, *p;
591 int cplen;
592
593 compatible = of_get_property(node, "compatible", &cplen);
594 if (!compatible || strlen(compatible) > cplen)
595 return -ENODEV;
596 p = strchr(compatible, ',');
597 strlcpy(modalias, p ? p + 1 : compatible, len);
598 return 0;
599}
600EXPORT_SYMBOL_GPL(of_modalias_node);
601
602/**
603 * of_find_node_by_phandle - Find a node given a phandle
604 * @handle: phandle of the node to find
605 *
606 * Returns a node pointer with refcount incremented, use
607 * of_node_put() on it when done.
608 */
609struct device_node *of_find_node_by_phandle(phandle handle)
610{
611 struct device_node *np;
612
613 read_lock(&devtree_lock);
614 for (np = allnodes; np; np = np->allnext)
615 if (np->phandle == handle)
616 break;
617 of_node_get(np);
618 read_unlock(&devtree_lock);
619 return np;
620}
621EXPORT_SYMBOL(of_find_node_by_phandle);
622
623/**
624 * of_property_read_u32_array - Find and read an array of 32 bit integers
625 * from a property.
626 *
627 * @np: device node from which the property value is to be read.
628 * @propname: name of the property to be searched.
629 * @out_value: pointer to return value, modified only if return value is 0.
630 *
631 * Search for a property in a device node and read 32-bit value(s) from
632 * it. Returns 0 on success, -EINVAL if the property does not exist,
633 * -ENODATA if property does not have a value, and -EOVERFLOW if the
634 * property data isn't large enough.
635 *
636 * The out_value is modified only if a valid u32 value can be decoded.
637 */
638int of_property_read_u32_array(const struct device_node *np,
639 const char *propname, u32 *out_values,
640 size_t sz)
641{
642 struct property *prop = of_find_property(np, propname, NULL);
643 const __be32 *val;
644
645 if (!prop)
646 return -EINVAL;
647 if (!prop->value)
648 return -ENODATA;
649 if ((sz * sizeof(*out_values)) > prop->length)
650 return -EOVERFLOW;
651
652 val = prop->value;
653 while (sz--)
654 *out_values++ = be32_to_cpup(val++);
655 return 0;
656}
657EXPORT_SYMBOL_GPL(of_property_read_u32_array);
658
659/**
660 * of_property_read_u64 - Find and read a 64 bit integer from a property
661 * @np: device node from which the property value is to be read.
662 * @propname: name of the property to be searched.
663 * @out_value: pointer to return value, modified only if return value is 0.
664 *
665 * Search for a property in a device node and read a 64-bit value from
666 * it. Returns 0 on success, -EINVAL if the property does not exist,
667 * -ENODATA if property does not have a value, and -EOVERFLOW if the
668 * property data isn't large enough.
669 *
670 * The out_value is modified only if a valid u64 value can be decoded.
671 */
672int of_property_read_u64(const struct device_node *np, const char *propname,
673 u64 *out_value)
674{
675 struct property *prop = of_find_property(np, propname, NULL);
676
677 if (!prop)
678 return -EINVAL;
679 if (!prop->value)
680 return -ENODATA;
681 if (sizeof(*out_value) > prop->length)
682 return -EOVERFLOW;
683 *out_value = of_read_number(prop->value, 2);
684 return 0;
685}
686EXPORT_SYMBOL_GPL(of_property_read_u64);
687
688/**
689 * of_property_read_string - Find and read a string from a property
690 * @np: device node from which the property value is to be read.
691 * @propname: name of the property to be searched.
692 * @out_string: pointer to null terminated return string, modified only if
693 * return value is 0.
694 *
695 * Search for a property in a device tree node and retrieve a null
696 * terminated string value (pointer to data, not a copy). Returns 0 on
697 * success, -EINVAL if the property does not exist, -ENODATA if property
698 * does not have a value, and -EILSEQ if the string is not null-terminated
699 * within the length of the property data.
700 *
701 * The out_string pointer is modified only if a valid string can be decoded.
702 */
703int of_property_read_string(struct device_node *np, const char *propname,
704 const char **out_string)
705{
706 struct property *prop = of_find_property(np, propname, NULL);
707 if (!prop)
708 return -EINVAL;
709 if (!prop->value)
710 return -ENODATA;
711 if (strnlen(prop->value, prop->length) >= prop->length)
712 return -EILSEQ;
713 *out_string = prop->value;
714 return 0;
715}
716EXPORT_SYMBOL_GPL(of_property_read_string);
717
718/**
719 * of_property_read_string_index - Find and read a string from a multiple
720 * strings property.
721 * @np: device node from which the property value is to be read.
722 * @propname: name of the property to be searched.
723 * @index: index of the string in the list of strings
724 * @out_string: pointer to null terminated return string, modified only if
725 * return value is 0.
726 *
727 * Search for a property in a device tree node and retrieve a null
728 * terminated string value (pointer to data, not a copy) in the list of strings
729 * contained in that property.
730 * Returns 0 on success, -EINVAL if the property does not exist, -ENODATA if
731 * property does not have a value, and -EILSEQ if the string is not
732 * null-terminated within the length of the property data.
733 *
734 * The out_string pointer is modified only if a valid string can be decoded.
735 */
736int of_property_read_string_index(struct device_node *np, const char *propname,
737 int index, const char **output)
738{
739 struct property *prop = of_find_property(np, propname, NULL);
740 int i = 0;
741 size_t l = 0, total = 0;
742 const char *p;
743
744 if (!prop)
745 return -EINVAL;
746 if (!prop->value)
747 return -ENODATA;
748 if (strnlen(prop->value, prop->length) >= prop->length)
749 return -EILSEQ;
750
751 p = prop->value;
752
753 for (i = 0; total < prop->length; total += l, p += l) {
754 l = strlen(p) + 1;
755 if (i++ == index) {
756 *output = p;
757 return 0;
758 }
759 }
760 return -ENODATA;
761}
762EXPORT_SYMBOL_GPL(of_property_read_string_index);
763
764/**
765 * of_property_match_string() - Find string in a list and return index
766 * @np: pointer to node containing string list property
767 * @propname: string list property name
768 * @string: pointer to string to search for in string list
769 *
770 * This function searches a string list property and returns the index
771 * of a specific string value.
772 */
773int of_property_match_string(struct device_node *np, const char *propname,
774 const char *string)
775{
776 struct property *prop = of_find_property(np, propname, NULL);
777 size_t l;
778 int i;
779 const char *p, *end;
780
781 if (!prop)
782 return -EINVAL;
783 if (!prop->value)
784 return -ENODATA;
785
786 p = prop->value;
787 end = p + prop->length;
788
789 for (i = 0; p < end; i++, p += l) {
790 l = strlen(p) + 1;
791 if (p + l > end)
792 return -EILSEQ;
793 pr_debug("comparing %s with %s\n", string, p);
794 if (strcmp(string, p) == 0)
795 return i; /* Found it; return index */
796 }
797 return -ENODATA;
798}
799EXPORT_SYMBOL_GPL(of_property_match_string);
800
801/**
802 * of_property_count_strings - Find and return the number of strings from a
803 * multiple strings property.
804 * @np: device node from which the property value is to be read.
805 * @propname: name of the property to be searched.
806 *
807 * Search for a property in a device tree node and retrieve the number of null
808 * terminated string contain in it. Returns the number of strings on
809 * success, -EINVAL if the property does not exist, -ENODATA if property
810 * does not have a value, and -EILSEQ if the string is not null-terminated
811 * within the length of the property data.
812 */
813int of_property_count_strings(struct device_node *np, const char *propname)
814{
815 struct property *prop = of_find_property(np, propname, NULL);
816 int i = 0;
817 size_t l = 0, total = 0;
818 const char *p;
819
820 if (!prop)
821 return -EINVAL;
822 if (!prop->value)
823 return -ENODATA;
824 if (strnlen(prop->value, prop->length) >= prop->length)
825 return -EILSEQ;
826
827 p = prop->value;
828
829 for (i = 0; total < prop->length; total += l, p += l, i++)
830 l = strlen(p) + 1;
831
832 return i;
833}
834EXPORT_SYMBOL_GPL(of_property_count_strings);
835
836/**
837 * of_parse_phandle - Resolve a phandle property to a device_node pointer
838 * @np: Pointer to device node holding phandle property
839 * @phandle_name: Name of property holding a phandle value
840 * @index: For properties holding a table of phandles, this is the index into
841 * the table
842 *
843 * Returns the device_node pointer with refcount incremented. Use
844 * of_node_put() on it when done.
845 */
846struct device_node *
847of_parse_phandle(struct device_node *np, const char *phandle_name, int index)
848{
849 const __be32 *phandle;
850 int size;
851
852 phandle = of_get_property(np, phandle_name, &size);
853 if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
854 return NULL;
855
856 return of_find_node_by_phandle(be32_to_cpup(phandle + index));
857}
858EXPORT_SYMBOL(of_parse_phandle);
859
860/**
861 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
862 * @np: pointer to a device tree node containing a list
863 * @list_name: property name that contains a list
864 * @cells_name: property name that specifies phandles' arguments count
865 * @index: index of a phandle to parse out
866 * @out_args: optional pointer to output arguments structure (will be filled)
867 *
868 * This function is useful to parse lists of phandles and their arguments.
869 * Returns 0 on success and fills out_args, on error returns appropriate
870 * errno value.
871 *
872 * Caller is responsible to call of_node_put() on the returned out_args->node
873 * pointer.
874 *
875 * Example:
876 *
877 * phandle1: node1 {
878 * #list-cells = <2>;
879 * }
880 *
881 * phandle2: node2 {
882 * #list-cells = <1>;
883 * }
884 *
885 * node3 {
886 * list = <&phandle1 1 2 &phandle2 3>;
887 * }
888 *
889 * To get a device_node of the `node2' node you may call this:
890 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
891 */
892int of_parse_phandle_with_args(struct device_node *np, const char *list_name,
893 const char *cells_name, int index,
894 struct of_phandle_args *out_args)
895{
896 const __be32 *list, *list_end;
897 int size, cur_index = 0;
898 uint32_t count = 0;
899 struct device_node *node = NULL;
900 phandle phandle;
901
902 /* Retrieve the phandle list property */
903 list = of_get_property(np, list_name, &size);
904 if (!list)
905 return -EINVAL;
906 list_end = list + size / sizeof(*list);
907
908 /* Loop over the phandles until all the requested entry is found */
909 while (list < list_end) {
910 count = 0;
911
912 /*
913 * If phandle is 0, then it is an empty entry with no
914 * arguments. Skip forward to the next entry.
915 */
916 phandle = be32_to_cpup(list++);
917 if (phandle) {
918 /*
919 * Find the provider node and parse the #*-cells
920 * property to determine the argument length
921 */
922 node = of_find_node_by_phandle(phandle);
923 if (!node) {
924 pr_err("%s: could not find phandle\n",
925 np->full_name);
926 break;
927 }
928 if (of_property_read_u32(node, cells_name, &count)) {
929 pr_err("%s: could not get %s for %s\n",
930 np->full_name, cells_name,
931 node->full_name);
932 break;
933 }
934
935 /*
936 * Make sure that the arguments actually fit in the
937 * remaining property data length
938 */
939 if (list + count > list_end) {
940 pr_err("%s: arguments longer than property\n",
941 np->full_name);
942 break;
943 }
944 }
945
946 /*
947 * All of the error cases above bail out of the loop, so at
948 * this point, the parsing is successful. If the requested
949 * index matches, then fill the out_args structure and return,
950 * or return -ENOENT for an empty entry.
951 */
952 if (cur_index == index) {
953 if (!phandle)
954 return -ENOENT;
955
956 if (out_args) {
957 int i;
958 if (WARN_ON(count > MAX_PHANDLE_ARGS))
959 count = MAX_PHANDLE_ARGS;
960 out_args->np = node;
961 out_args->args_count = count;
962 for (i = 0; i < count; i++)
963 out_args->args[i] = be32_to_cpup(list++);
964 }
965 return 0;
966 }
967
968 of_node_put(node);
969 node = NULL;
970 list += count;
971 cur_index++;
972 }
973
974 /* Loop exited without finding a valid entry; return an error */
975 if (node)
976 of_node_put(node);
977 return -EINVAL;
978}
979EXPORT_SYMBOL(of_parse_phandle_with_args);
980
981/**
982 * prom_add_property - Add a property to a node
983 */
984int prom_add_property(struct device_node *np, struct property *prop)
985{
986 struct property **next;
987 unsigned long flags;
988
989 prop->next = NULL;
990 write_lock_irqsave(&devtree_lock, flags);
991 next = &np->properties;
992 while (*next) {
993 if (strcmp(prop->name, (*next)->name) == 0) {
994 /* duplicate ! don't insert it */
995 write_unlock_irqrestore(&devtree_lock, flags);
996 return -1;
997 }
998 next = &(*next)->next;
999 }
1000 *next = prop;
1001 write_unlock_irqrestore(&devtree_lock, flags);
1002
1003#ifdef CONFIG_PROC_DEVICETREE
1004 /* try to add to proc as well if it was initialized */
1005 if (np->pde)
1006 proc_device_tree_add_prop(np->pde, prop);
1007#endif /* CONFIG_PROC_DEVICETREE */
1008
1009 return 0;
1010}
1011
1012/**
1013 * prom_remove_property - Remove a property from a node.
1014 *
1015 * Note that we don't actually remove it, since we have given out
1016 * who-knows-how-many pointers to the data using get-property.
1017 * Instead we just move the property to the "dead properties"
1018 * list, so it won't be found any more.
1019 */
1020int prom_remove_property(struct device_node *np, struct property *prop)
1021{
1022 struct property **next;
1023 unsigned long flags;
1024 int found = 0;
1025
1026 write_lock_irqsave(&devtree_lock, flags);
1027 next = &np->properties;
1028 while (*next) {
1029 if (*next == prop) {
1030 /* found the node */
1031 *next = prop->next;
1032 prop->next = np->deadprops;
1033 np->deadprops = prop;
1034 found = 1;
1035 break;
1036 }
1037 next = &(*next)->next;
1038 }
1039 write_unlock_irqrestore(&devtree_lock, flags);
1040
1041 if (!found)
1042 return -ENODEV;
1043
1044#ifdef CONFIG_PROC_DEVICETREE
1045 /* try to remove the proc node as well */
1046 if (np->pde)
1047 proc_device_tree_remove_prop(np->pde, prop);
1048#endif /* CONFIG_PROC_DEVICETREE */
1049
1050 return 0;
1051}
1052
1053/*
1054 * prom_update_property - Update a property in a node.
1055 *
1056 * Note that we don't actually remove it, since we have given out
1057 * who-knows-how-many pointers to the data using get-property.
1058 * Instead we just move the property to the "dead properties" list,
1059 * and add the new property to the property list
1060 */
1061int prom_update_property(struct device_node *np,
1062 struct property *newprop,
1063 struct property *oldprop)
1064{
1065 struct property **next;
1066 unsigned long flags;
1067 int found = 0;
1068
1069 write_lock_irqsave(&devtree_lock, flags);
1070 next = &np->properties;
1071 while (*next) {
1072 if (*next == oldprop) {
1073 /* found the node */
1074 newprop->next = oldprop->next;
1075 *next = newprop;
1076 oldprop->next = np->deadprops;
1077 np->deadprops = oldprop;
1078 found = 1;
1079 break;
1080 }
1081 next = &(*next)->next;
1082 }
1083 write_unlock_irqrestore(&devtree_lock, flags);
1084
1085 if (!found)
1086 return -ENODEV;
1087
1088#ifdef CONFIG_PROC_DEVICETREE
1089 /* try to add to proc as well if it was initialized */
1090 if (np->pde)
1091 proc_device_tree_update_prop(np->pde, newprop, oldprop);
1092#endif /* CONFIG_PROC_DEVICETREE */
1093
1094 return 0;
1095}
1096
1097#if defined(CONFIG_OF_DYNAMIC)
1098/*
1099 * Support for dynamic device trees.
1100 *
1101 * On some platforms, the device tree can be manipulated at runtime.
1102 * The routines in this section support adding, removing and changing
1103 * device tree nodes.
1104 */
1105
1106/**
1107 * of_attach_node - Plug a device node into the tree and global list.
1108 */
1109void of_attach_node(struct device_node *np)
1110{
1111 unsigned long flags;
1112
1113 write_lock_irqsave(&devtree_lock, flags);
1114 np->sibling = np->parent->child;
1115 np->allnext = allnodes;
1116 np->parent->child = np;
1117 allnodes = np;
1118 write_unlock_irqrestore(&devtree_lock, flags);
1119}
1120
1121/**
1122 * of_detach_node - "Unplug" a node from the device tree.
1123 *
1124 * The caller must hold a reference to the node. The memory associated with
1125 * the node is not freed until its refcount goes to zero.
1126 */
1127void of_detach_node(struct device_node *np)
1128{
1129 struct device_node *parent;
1130 unsigned long flags;
1131
1132 write_lock_irqsave(&devtree_lock, flags);
1133
1134 parent = np->parent;
1135 if (!parent)
1136 goto out_unlock;
1137
1138 if (allnodes == np)
1139 allnodes = np->allnext;
1140 else {
1141 struct device_node *prev;
1142 for (prev = allnodes;
1143 prev->allnext != np;
1144 prev = prev->allnext)
1145 ;
1146 prev->allnext = np->allnext;
1147 }
1148
1149 if (parent->child == np)
1150 parent->child = np->sibling;
1151 else {
1152 struct device_node *prevsib;
1153 for (prevsib = np->parent->child;
1154 prevsib->sibling != np;
1155 prevsib = prevsib->sibling)
1156 ;
1157 prevsib->sibling = np->sibling;
1158 }
1159
1160 of_node_set_flag(np, OF_DETACHED);
1161
1162out_unlock:
1163 write_unlock_irqrestore(&devtree_lock, flags);
1164}
1165#endif /* defined(CONFIG_OF_DYNAMIC) */
1166
1167static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1168 int id, const char *stem, int stem_len)
1169{
1170 ap->np = np;
1171 ap->id = id;
1172 strncpy(ap->stem, stem, stem_len);
1173 ap->stem[stem_len] = 0;
1174 list_add_tail(&ap->link, &aliases_lookup);
1175 pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
1176 ap->alias, ap->stem, ap->id, np ? np->full_name : NULL);
1177}
1178
1179/**
1180 * of_alias_scan - Scan all properties of 'aliases' node
1181 *
1182 * The function scans all the properties of 'aliases' node and populate
1183 * the the global lookup table with the properties. It returns the
1184 * number of alias_prop found, or error code in error case.
1185 *
1186 * @dt_alloc: An allocator that provides a virtual address to memory
1187 * for the resulting tree
1188 */
1189void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1190{
1191 struct property *pp;
1192
1193 of_chosen = of_find_node_by_path("/chosen");
1194 if (of_chosen == NULL)
1195 of_chosen = of_find_node_by_path("/chosen@0");
1196 of_aliases = of_find_node_by_path("/aliases");
1197 if (!of_aliases)
1198 return;
1199
1200 for_each_property_of_node(of_aliases, pp) {
1201 const char *start = pp->name;
1202 const char *end = start + strlen(start);
1203 struct device_node *np;
1204 struct alias_prop *ap;
1205 int id, len;
1206
1207 /* Skip those we do not want to proceed */
1208 if (!strcmp(pp->name, "name") ||
1209 !strcmp(pp->name, "phandle") ||
1210 !strcmp(pp->name, "linux,phandle"))
1211 continue;
1212
1213 np = of_find_node_by_path(pp->value);
1214 if (!np)
1215 continue;
1216
1217 /* walk the alias backwards to extract the id and work out
1218 * the 'stem' string */
1219 while (isdigit(*(end-1)) && end > start)
1220 end--;
1221 len = end - start;
1222
1223 if (kstrtoint(end, 10, &id) < 0)
1224 continue;
1225
1226 /* Allocate an alias_prop with enough space for the stem */
1227 ap = dt_alloc(sizeof(*ap) + len + 1, 4);
1228 if (!ap)
1229 continue;
1230 ap->alias = start;
1231 of_alias_add(ap, np, id, start, len);
1232 }
1233}
1234
1235/**
1236 * of_alias_get_id - Get alias id for the given device_node
1237 * @np: Pointer to the given device_node
1238 * @stem: Alias stem of the given device_node
1239 *
1240 * The function travels the lookup table to get alias id for the given
1241 * device_node and alias stem. It returns the alias id if find it.
1242 */
1243int of_alias_get_id(struct device_node *np, const char *stem)
1244{
1245 struct alias_prop *app;
1246 int id = -ENODEV;
1247
1248 mutex_lock(&of_aliases_mutex);
1249 list_for_each_entry(app, &aliases_lookup, link) {
1250 if (strcmp(app->stem, stem) != 0)
1251 continue;
1252
1253 if (np == app->np) {
1254 id = app->id;
1255 break;
1256 }
1257 }
1258 mutex_unlock(&of_aliases_mutex);
1259
1260 return id;
1261}
1262EXPORT_SYMBOL_GPL(of_alias_get_id);
1263
1264const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
1265 u32 *pu)
1266{
1267 const void *curv = cur;
1268
1269 if (!prop)
1270 return NULL;
1271
1272 if (!cur) {
1273 curv = prop->value;
1274 goto out_val;
1275 }
1276
1277 curv += sizeof(*cur);
1278 if (curv >= prop->value + prop->length)
1279 return NULL;
1280
1281out_val:
1282 *pu = be32_to_cpup(curv);
1283 return curv;
1284}
1285EXPORT_SYMBOL_GPL(of_prop_next_u32);
1286
1287const char *of_prop_next_string(struct property *prop, const char *cur)
1288{
1289 const void *curv = cur;
1290
1291 if (!prop)
1292 return NULL;
1293
1294 if (!cur)
1295 return prop->value;
1296
1297 curv += strlen(cur) + 1;
1298 if (curv >= prop->value + prop->length)
1299 return NULL;
1300
1301 return curv;
1302}
1303EXPORT_SYMBOL_GPL(of_prop_next_string);