blob: 133908a6fd8db5270f3845ce387b3724d3845b7d [file] [log] [blame]
Stephen Rothwell97e873e2007-05-01 16:26:07 +10001/*
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 *
Grant Likelye91edcf2009-10-15 10:58:09 -060012 * Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
13 * Grant Likely.
Stephen Rothwell97e873e2007-05-01 16:26:07 +100014 *
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 */
Shawn Guo611cad72011-08-15 15:28:14 +080020#include <linux/ctype.h>
Stephen Rothwell97e873e2007-05-01 16:26:07 +100021#include <linux/module.h>
22#include <linux/of.h>
Stephen Rothwell581b6052007-04-24 16:46:53 +100023#include <linux/spinlock.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090024#include <linux/slab.h>
Jeremy Kerra9f2f632010-02-01 21:34:14 -070025#include <linux/proc_fs.h>
Stephen Rothwell581b6052007-04-24 16:46:53 +100026
Shawn Guo611cad72011-08-15 15:28:14 +080027/**
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
Stephen Rothwell1ef4d422007-04-24 17:57:33 +100048struct device_node *allnodes;
Grant Likelyfc0bdae2010-02-14 07:13:55 -070049struct device_node *of_chosen;
Shawn Guo611cad72011-08-15 15:28:14 +080050struct device_node *of_aliases;
51
52static DEFINE_MUTEX(of_aliases_mutex);
Stephen Rothwell1ef4d422007-04-24 17:57:33 +100053
Stephen Rothwell581b6052007-04-24 16:46:53 +100054/* use when traversing tree through the allnext, child, sibling,
55 * or parent members of struct device_node.
56 */
57DEFINE_RWLOCK(devtree_lock);
Stephen Rothwell97e873e2007-05-01 16:26:07 +100058
59int of_n_addr_cells(struct device_node *np)
60{
Jeremy Kerra9fadee2010-10-10 21:24:10 -060061 const __be32 *ip;
Stephen Rothwell97e873e2007-05-01 16:26:07 +100062
63 do {
64 if (np->parent)
65 np = np->parent;
66 ip = of_get_property(np, "#address-cells", NULL);
67 if (ip)
Jeremy Kerr33714882010-01-30 01:45:26 -070068 return be32_to_cpup(ip);
Stephen Rothwell97e873e2007-05-01 16:26:07 +100069 } 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{
Jeremy Kerra9fadee2010-10-10 21:24:10 -060077 const __be32 *ip;
Stephen Rothwell97e873e2007-05-01 16:26:07 +100078
79 do {
80 if (np->parent)
81 np = np->parent;
82 ip = of_get_property(np, "#size-cells", NULL);
83 if (ip)
Jeremy Kerr33714882010-01-30 01:45:26 -070084 return be32_to_cpup(ip);
Stephen Rothwell97e873e2007-05-01 16:26:07 +100085 } 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
Grant Likely923f7e32010-01-28 13:52:53 -070091#if !defined(CONFIG_SPARC) /* SPARC doesn't do ref counting (yet) */
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_SPARC */
165
Stephen Rothwell581b6052007-04-24 16:46:53 +1000166struct property *of_find_property(const struct device_node *np,
167 const char *name,
168 int *lenp)
169{
170 struct property *pp;
171
Timur Tabi64e45662008-05-08 05:19:59 +1000172 if (!np)
173 return NULL;
174
Stephen Rothwell581b6052007-04-24 16:46:53 +1000175 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
Grant Likelye91edcf2009-10-15 10:58:09 -0600189/**
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
Stephen Rothwell97e873e2007-05-01 16:26:07 +1000212/*
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);
Stephen Rothwell0081cbc2007-05-01 16:29:19 +1000224
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);
Stephen Rothwelle679c5f2007-04-24 17:16:16 +1000248
249/**
Grant Likely71a157e2010-02-01 21:34:14 -0700250 * of_machine_is_compatible - Test root of device tree for a given compatible value
Grant Likely1f43cfb2010-01-28 13:47:25 -0700251 * @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 */
Grant Likely71a157e2010-02-01 21:34:14 -0700256int of_machine_is_compatible(const char *compat)
Grant Likely1f43cfb2010-01-28 13:47:25 -0700257{
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}
Grant Likely71a157e2010-02-01 21:34:14 -0700268EXPORT_SYMBOL(of_machine_is_compatible);
Grant Likely1f43cfb2010-01-28 13:47:25 -0700269
270/**
Josh Boyer834d97d2008-03-27 00:33:14 +1100271 * 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/**
Stephen Rothwelle679c5f2007-04-24 17:16:16 +1000297 * 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);
Stephen Rothwelld1cd3552007-04-24 17:21:29 +1000316
317/**
Michael Ellermanf4eb0102007-10-26 16:54:31 +1000318 * 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/**
Stephen Rothwelld1cd3552007-04-24 17:21:29 +1000343 * 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);
Stephen Rothwell1ef4d422007-04-24 17:57:33 +1000365
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);
Grant Likely283029d2008-01-09 06:20:40 +1100478
479/**
Michael Ellerman1e291b12008-11-12 18:54:42 +0000480 * 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/**
Grant Likely283029d2008-01-09 06:20:40 +1100515 * 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{
Grant Likelya52f07e2011-03-18 10:21:29 -0600524 if (!matches)
525 return NULL;
526
Grant Likely283029d2008-01-09 06:20:40 +1100527 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);
Grant Likely3f07af42008-07-25 22:25:13 -0400574
575/**
Grant Likely3f07af42008-07-25 22:25:13 -0400576 * 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 *
Grant Likely2ffe8c52010-06-08 07:48:19 -0600581 * 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.
Grant Likely3f07af42008-07-25 22:25:13 -0400585 *
Grant Likely2ffe8c52010-06-08 07:48:19 -0600586 * This routine returns 0 on success, <0 on failure.
Grant Likely3f07af42008-07-25 22:25:13 -0400587 */
588int of_modalias_node(struct device_node *node, char *modalias, int len)
589{
Grant Likely2ffe8c52010-06-08 07:48:19 -0600590 const char *compatible, *p;
591 int cplen;
Grant Likely3f07af42008-07-25 22:25:13 -0400592
593 compatible = of_get_property(node, "compatible", &cplen);
Grant Likely2ffe8c52010-06-08 07:48:19 -0600594 if (!compatible || strlen(compatible) > cplen)
Grant Likely3f07af42008-07-25 22:25:13 -0400595 return -ENODEV;
Grant Likely3f07af42008-07-25 22:25:13 -0400596 p = strchr(compatible, ',');
Grant Likely2ffe8c52010-06-08 07:48:19 -0600597 strlcpy(modalias, p ? p + 1 : compatible, len);
Grant Likely3f07af42008-07-25 22:25:13 -0400598 return 0;
599}
600EXPORT_SYMBOL_GPL(of_modalias_node);
601
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000602/**
Jeremy Kerr89751a72010-02-01 21:34:11 -0700603 * 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/**
Rob Herring0e373632011-07-06 15:42:58 -0500624 * of_property_read_u32_array - Find and read an array of 32 bit integers
625 * from a property.
626 *
Thomas Abrahama3b85362011-06-30 21:26:10 +0530627 * @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 *
Rob Herring0e373632011-07-06 15:42:58 -0500631 * Search for a property in a device node and read 32-bit value(s) from
Thomas Abrahama3b85362011-06-30 21:26:10 +0530632 * 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 */
Jamie Ilesaac285c2011-08-02 15:45:07 +0100638int of_property_read_u32_array(const struct device_node *np,
639 const char *propname, u32 *out_values,
640 size_t sz)
Thomas Abrahama3b85362011-06-30 21:26:10 +0530641{
642 struct property *prop = of_find_property(np, propname, NULL);
Rob Herring0e373632011-07-06 15:42:58 -0500643 const __be32 *val;
Thomas Abrahama3b85362011-06-30 21:26:10 +0530644
645 if (!prop)
646 return -EINVAL;
647 if (!prop->value)
648 return -ENODATA;
Rob Herring0e373632011-07-06 15:42:58 -0500649 if ((sz * sizeof(*out_values)) > prop->length)
Thomas Abrahama3b85362011-06-30 21:26:10 +0530650 return -EOVERFLOW;
Rob Herring0e373632011-07-06 15:42:58 -0500651
652 val = prop->value;
653 while (sz--)
654 *out_values++ = be32_to_cpup(val++);
Thomas Abrahama3b85362011-06-30 21:26:10 +0530655 return 0;
656}
Rob Herring0e373632011-07-06 15:42:58 -0500657EXPORT_SYMBOL_GPL(of_property_read_u32_array);
Thomas Abrahama3b85362011-06-30 21:26:10 +0530658
659/**
Jamie Iles4cd7f7a2011-09-14 20:49:59 +0100660 * 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/**
Thomas Abrahama3b85362011-06-30 21:26:10 +0530689 * 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 */
Jamie Ilesaac285c2011-08-02 15:45:07 +0100703int of_property_read_string(struct device_node *np, const char *propname,
Shawn Guof09bc832011-07-04 09:01:18 +0800704 const char **out_string)
Thomas Abrahama3b85362011-06-30 21:26:10 +0530705{
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/**
Benoit Cousson4fcd15a2011-09-27 17:45:43 +0200719 * 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;
Benoit Cousson88af7f52011-12-05 15:23:54 +0100755 if (i++ == index) {
Benoit Cousson4fcd15a2011-09-27 17:45:43 +0200756 *output = p;
757 return 0;
758 }
759 }
760 return -ENODATA;
761}
762EXPORT_SYMBOL_GPL(of_property_read_string_index);
763
764
765/**
766 * of_property_count_strings - Find and return the number of strings from a
767 * multiple strings property.
768 * @np: device node from which the property value is to be read.
769 * @propname: name of the property to be searched.
770 *
771 * Search for a property in a device tree node and retrieve the number of null
772 * terminated string contain in it. Returns the number of strings on
773 * success, -EINVAL if the property does not exist, -ENODATA if property
774 * does not have a value, and -EILSEQ if the string is not null-terminated
775 * within the length of the property data.
776 */
777int of_property_count_strings(struct device_node *np, const char *propname)
778{
779 struct property *prop = of_find_property(np, propname, NULL);
780 int i = 0;
781 size_t l = 0, total = 0;
782 const char *p;
783
784 if (!prop)
785 return -EINVAL;
786 if (!prop->value)
787 return -ENODATA;
788 if (strnlen(prop->value, prop->length) >= prop->length)
789 return -EILSEQ;
790
791 p = prop->value;
792
Benoit Cousson88af7f52011-12-05 15:23:54 +0100793 for (i = 0; total < prop->length; total += l, p += l, i++)
Benoit Cousson4fcd15a2011-09-27 17:45:43 +0200794 l = strlen(p) + 1;
Benoit Cousson88af7f52011-12-05 15:23:54 +0100795
Benoit Cousson4fcd15a2011-09-27 17:45:43 +0200796 return i;
797}
798EXPORT_SYMBOL_GPL(of_property_count_strings);
799
800/**
Grant Likely739649c2009-04-25 12:52:40 +0000801 * of_parse_phandle - Resolve a phandle property to a device_node pointer
802 * @np: Pointer to device node holding phandle property
803 * @phandle_name: Name of property holding a phandle value
804 * @index: For properties holding a table of phandles, this is the index into
805 * the table
806 *
807 * Returns the device_node pointer with refcount incremented. Use
808 * of_node_put() on it when done.
809 */
810struct device_node *
811of_parse_phandle(struct device_node *np, const char *phandle_name, int index)
812{
Grant Likely9a6b2e52010-07-23 01:48:25 -0600813 const __be32 *phandle;
Grant Likely739649c2009-04-25 12:52:40 +0000814 int size;
815
816 phandle = of_get_property(np, phandle_name, &size);
817 if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
818 return NULL;
819
Grant Likely9a6b2e52010-07-23 01:48:25 -0600820 return of_find_node_by_phandle(be32_to_cpup(phandle + index));
Grant Likely739649c2009-04-25 12:52:40 +0000821}
822EXPORT_SYMBOL(of_parse_phandle);
823
824/**
Grant Likely15c9a0a2011-12-12 09:25:57 -0700825 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000826 * @np: pointer to a device tree node containing a list
827 * @list_name: property name that contains a list
828 * @cells_name: property name that specifies phandles' arguments count
829 * @index: index of a phandle to parse out
Grant Likely15c9a0a2011-12-12 09:25:57 -0700830 * @out_args: optional pointer to output arguments structure (will be filled)
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000831 *
832 * This function is useful to parse lists of phandles and their arguments.
Grant Likely15c9a0a2011-12-12 09:25:57 -0700833 * Returns 0 on success and fills out_args, on error returns appropriate
834 * errno value.
835 *
836 * Caller is responsible to call of_node_put() on the returned out_args->node
837 * pointer.
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000838 *
839 * Example:
840 *
841 * phandle1: node1 {
842 * #list-cells = <2>;
843 * }
844 *
845 * phandle2: node2 {
846 * #list-cells = <1>;
847 * }
848 *
849 * node3 {
850 * list = <&phandle1 1 2 &phandle2 3>;
851 * }
852 *
853 * To get a device_node of the `node2' node you may call this:
Grant Likely15c9a0a2011-12-12 09:25:57 -0700854 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000855 */
Grant Likely15c9a0a2011-12-12 09:25:57 -0700856int of_parse_phandle_with_args(struct device_node *np, const char *list_name,
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000857 const char *cells_name, int index,
Grant Likely15c9a0a2011-12-12 09:25:57 -0700858 struct of_phandle_args *out_args)
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000859{
Grant Likely15c9a0a2011-12-12 09:25:57 -0700860 const __be32 *list, *list_end;
861 int size, cur_index = 0;
862 uint32_t count = 0;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000863 struct device_node *node = NULL;
Grant Likely15c9a0a2011-12-12 09:25:57 -0700864 phandle phandle;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000865
Grant Likely15c9a0a2011-12-12 09:25:57 -0700866 /* Retrieve the phandle list property */
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000867 list = of_get_property(np, list_name, &size);
Grant Likely15c9a0a2011-12-12 09:25:57 -0700868 if (!list)
869 return -EINVAL;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000870 list_end = list + size / sizeof(*list);
871
Grant Likely15c9a0a2011-12-12 09:25:57 -0700872 /* Loop over the phandles until all the requested entry is found */
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000873 while (list < list_end) {
Grant Likely15c9a0a2011-12-12 09:25:57 -0700874 count = 0;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000875
Grant Likely15c9a0a2011-12-12 09:25:57 -0700876 /*
877 * If phandle is 0, then it is an empty entry with no
878 * arguments. Skip forward to the next entry.
879 */
Grant Likely9a6b2e52010-07-23 01:48:25 -0600880 phandle = be32_to_cpup(list++);
Grant Likely15c9a0a2011-12-12 09:25:57 -0700881 if (phandle) {
882 /*
883 * Find the provider node and parse the #*-cells
884 * property to determine the argument length
885 */
886 node = of_find_node_by_phandle(phandle);
887 if (!node) {
888 pr_err("%s: could not find phandle\n",
889 np->full_name);
890 break;
891 }
892 if (of_property_read_u32(node, cells_name, &count)) {
893 pr_err("%s: could not get %s for %s\n",
894 np->full_name, cells_name,
895 node->full_name);
896 break;
897 }
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000898
Grant Likely15c9a0a2011-12-12 09:25:57 -0700899 /*
900 * Make sure that the arguments actually fit in the
901 * remaining property data length
902 */
903 if (list + count > list_end) {
904 pr_err("%s: arguments longer than property\n",
905 np->full_name);
906 break;
907 }
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000908 }
909
Grant Likely15c9a0a2011-12-12 09:25:57 -0700910 /*
911 * All of the error cases above bail out of the loop, so at
912 * this point, the parsing is successful. If the requested
913 * index matches, then fill the out_args structure and return,
914 * or return -ENOENT for an empty entry.
915 */
916 if (cur_index == index) {
917 if (!phandle)
918 return -ENOENT;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000919
Grant Likely15c9a0a2011-12-12 09:25:57 -0700920 if (out_args) {
921 int i;
922 if (WARN_ON(count > MAX_PHANDLE_ARGS))
923 count = MAX_PHANDLE_ARGS;
924 out_args->np = node;
925 out_args->args_count = count;
926 for (i = 0; i < count; i++)
927 out_args->args[i] = be32_to_cpup(list++);
928 }
929 return 0;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000930 }
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000931
932 of_node_put(node);
933 node = NULL;
Grant Likely15c9a0a2011-12-12 09:25:57 -0700934 list += count;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000935 cur_index++;
936 }
937
Grant Likely15c9a0a2011-12-12 09:25:57 -0700938 /* Loop exited without finding a valid entry; return an error */
939 if (node)
940 of_node_put(node);
941 return -EINVAL;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000942}
Grant Likely15c9a0a2011-12-12 09:25:57 -0700943EXPORT_SYMBOL(of_parse_phandle_with_args);
Grant Likely02af11b2009-11-23 20:16:45 -0700944
945/**
946 * prom_add_property - Add a property to a node
947 */
948int prom_add_property(struct device_node *np, struct property *prop)
949{
950 struct property **next;
951 unsigned long flags;
952
953 prop->next = NULL;
954 write_lock_irqsave(&devtree_lock, flags);
955 next = &np->properties;
956 while (*next) {
957 if (strcmp(prop->name, (*next)->name) == 0) {
958 /* duplicate ! don't insert it */
959 write_unlock_irqrestore(&devtree_lock, flags);
960 return -1;
961 }
962 next = &(*next)->next;
963 }
964 *next = prop;
965 write_unlock_irqrestore(&devtree_lock, flags);
966
967#ifdef CONFIG_PROC_DEVICETREE
968 /* try to add to proc as well if it was initialized */
969 if (np->pde)
970 proc_device_tree_add_prop(np->pde, prop);
971#endif /* CONFIG_PROC_DEVICETREE */
972
973 return 0;
974}
975
976/**
977 * prom_remove_property - Remove a property from a node.
978 *
979 * Note that we don't actually remove it, since we have given out
980 * who-knows-how-many pointers to the data using get-property.
981 * Instead we just move the property to the "dead properties"
982 * list, so it won't be found any more.
983 */
984int prom_remove_property(struct device_node *np, struct property *prop)
985{
986 struct property **next;
987 unsigned long flags;
988 int found = 0;
989
990 write_lock_irqsave(&devtree_lock, flags);
991 next = &np->properties;
992 while (*next) {
993 if (*next == prop) {
994 /* found the node */
995 *next = prop->next;
996 prop->next = np->deadprops;
997 np->deadprops = prop;
998 found = 1;
999 break;
1000 }
1001 next = &(*next)->next;
1002 }
1003 write_unlock_irqrestore(&devtree_lock, flags);
1004
1005 if (!found)
1006 return -ENODEV;
1007
1008#ifdef CONFIG_PROC_DEVICETREE
1009 /* try to remove the proc node as well */
1010 if (np->pde)
1011 proc_device_tree_remove_prop(np->pde, prop);
1012#endif /* CONFIG_PROC_DEVICETREE */
1013
1014 return 0;
1015}
1016
1017/*
1018 * prom_update_property - Update a property in a node.
1019 *
1020 * Note that we don't actually remove it, since we have given out
1021 * who-knows-how-many pointers to the data using get-property.
1022 * Instead we just move the property to the "dead properties" list,
1023 * and add the new property to the property list
1024 */
1025int prom_update_property(struct device_node *np,
1026 struct property *newprop,
1027 struct property *oldprop)
1028{
1029 struct property **next;
1030 unsigned long flags;
1031 int found = 0;
1032
1033 write_lock_irqsave(&devtree_lock, flags);
1034 next = &np->properties;
1035 while (*next) {
1036 if (*next == oldprop) {
1037 /* found the node */
1038 newprop->next = oldprop->next;
1039 *next = newprop;
1040 oldprop->next = np->deadprops;
1041 np->deadprops = oldprop;
1042 found = 1;
1043 break;
1044 }
1045 next = &(*next)->next;
1046 }
1047 write_unlock_irqrestore(&devtree_lock, flags);
1048
1049 if (!found)
1050 return -ENODEV;
1051
1052#ifdef CONFIG_PROC_DEVICETREE
1053 /* try to add to proc as well if it was initialized */
1054 if (np->pde)
1055 proc_device_tree_update_prop(np->pde, newprop, oldprop);
1056#endif /* CONFIG_PROC_DEVICETREE */
1057
1058 return 0;
1059}
Grant Likelyfcdeb7f2010-01-29 05:04:33 -07001060
1061#if defined(CONFIG_OF_DYNAMIC)
1062/*
1063 * Support for dynamic device trees.
1064 *
1065 * On some platforms, the device tree can be manipulated at runtime.
1066 * The routines in this section support adding, removing and changing
1067 * device tree nodes.
1068 */
1069
1070/**
1071 * of_attach_node - Plug a device node into the tree and global list.
1072 */
1073void of_attach_node(struct device_node *np)
1074{
1075 unsigned long flags;
1076
1077 write_lock_irqsave(&devtree_lock, flags);
1078 np->sibling = np->parent->child;
1079 np->allnext = allnodes;
1080 np->parent->child = np;
1081 allnodes = np;
1082 write_unlock_irqrestore(&devtree_lock, flags);
1083}
1084
1085/**
1086 * of_detach_node - "Unplug" a node from the device tree.
1087 *
1088 * The caller must hold a reference to the node. The memory associated with
1089 * the node is not freed until its refcount goes to zero.
1090 */
1091void of_detach_node(struct device_node *np)
1092{
1093 struct device_node *parent;
1094 unsigned long flags;
1095
1096 write_lock_irqsave(&devtree_lock, flags);
1097
1098 parent = np->parent;
1099 if (!parent)
1100 goto out_unlock;
1101
1102 if (allnodes == np)
1103 allnodes = np->allnext;
1104 else {
1105 struct device_node *prev;
1106 for (prev = allnodes;
1107 prev->allnext != np;
1108 prev = prev->allnext)
1109 ;
1110 prev->allnext = np->allnext;
1111 }
1112
1113 if (parent->child == np)
1114 parent->child = np->sibling;
1115 else {
1116 struct device_node *prevsib;
1117 for (prevsib = np->parent->child;
1118 prevsib->sibling != np;
1119 prevsib = prevsib->sibling)
1120 ;
1121 prevsib->sibling = np->sibling;
1122 }
1123
1124 of_node_set_flag(np, OF_DETACHED);
1125
1126out_unlock:
1127 write_unlock_irqrestore(&devtree_lock, flags);
1128}
1129#endif /* defined(CONFIG_OF_DYNAMIC) */
1130
Shawn Guo611cad72011-08-15 15:28:14 +08001131static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1132 int id, const char *stem, int stem_len)
1133{
1134 ap->np = np;
1135 ap->id = id;
1136 strncpy(ap->stem, stem, stem_len);
1137 ap->stem[stem_len] = 0;
1138 list_add_tail(&ap->link, &aliases_lookup);
1139 pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
1140 ap->alias, ap->stem, ap->id, np ? np->full_name : NULL);
1141}
1142
1143/**
1144 * of_alias_scan - Scan all properties of 'aliases' node
1145 *
1146 * The function scans all the properties of 'aliases' node and populate
1147 * the the global lookup table with the properties. It returns the
1148 * number of alias_prop found, or error code in error case.
1149 *
1150 * @dt_alloc: An allocator that provides a virtual address to memory
1151 * for the resulting tree
1152 */
1153void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1154{
1155 struct property *pp;
1156
1157 of_chosen = of_find_node_by_path("/chosen");
1158 if (of_chosen == NULL)
1159 of_chosen = of_find_node_by_path("/chosen@0");
1160 of_aliases = of_find_node_by_path("/aliases");
1161 if (!of_aliases)
1162 return;
1163
Dong Aisheng8af0da92011-12-22 20:19:24 +08001164 for_each_property_of_node(of_aliases, pp) {
Shawn Guo611cad72011-08-15 15:28:14 +08001165 const char *start = pp->name;
1166 const char *end = start + strlen(start);
1167 struct device_node *np;
1168 struct alias_prop *ap;
1169 int id, len;
1170
1171 /* Skip those we do not want to proceed */
1172 if (!strcmp(pp->name, "name") ||
1173 !strcmp(pp->name, "phandle") ||
1174 !strcmp(pp->name, "linux,phandle"))
1175 continue;
1176
1177 np = of_find_node_by_path(pp->value);
1178 if (!np)
1179 continue;
1180
1181 /* walk the alias backwards to extract the id and work out
1182 * the 'stem' string */
1183 while (isdigit(*(end-1)) && end > start)
1184 end--;
1185 len = end - start;
1186
1187 if (kstrtoint(end, 10, &id) < 0)
1188 continue;
1189
1190 /* Allocate an alias_prop with enough space for the stem */
1191 ap = dt_alloc(sizeof(*ap) + len + 1, 4);
1192 if (!ap)
1193 continue;
1194 ap->alias = start;
1195 of_alias_add(ap, np, id, start, len);
1196 }
1197}
1198
1199/**
1200 * of_alias_get_id - Get alias id for the given device_node
1201 * @np: Pointer to the given device_node
1202 * @stem: Alias stem of the given device_node
1203 *
1204 * The function travels the lookup table to get alias id for the given
1205 * device_node and alias stem. It returns the alias id if find it.
1206 */
1207int of_alias_get_id(struct device_node *np, const char *stem)
1208{
1209 struct alias_prop *app;
1210 int id = -ENODEV;
1211
1212 mutex_lock(&of_aliases_mutex);
1213 list_for_each_entry(app, &aliases_lookup, link) {
1214 if (strcmp(app->stem, stem) != 0)
1215 continue;
1216
1217 if (np == app->np) {
1218 id = app->id;
1219 break;
1220 }
1221 }
1222 mutex_unlock(&of_aliases_mutex);
1223
1224 return id;
1225}
1226EXPORT_SYMBOL_GPL(of_alias_get_id);