blob: 69f85c07d17fc24718861b41618c6a8c0c493183 [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 *
12 * Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell.
13 *
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License
16 * as published by the Free Software Foundation; either version
17 * 2 of the License, or (at your option) any later version.
18 */
19#include <linux/module.h>
20#include <linux/of.h>
Stephen Rothwell581b6052007-04-24 16:46:53 +100021#include <linux/spinlock.h>
22
Stephen Rothwell1ef4d422007-04-24 17:57:33 +100023struct device_node *allnodes;
24
Stephen Rothwell581b6052007-04-24 16:46:53 +100025/* use when traversing tree through the allnext, child, sibling,
26 * or parent members of struct device_node.
27 */
28DEFINE_RWLOCK(devtree_lock);
Stephen Rothwell97e873e2007-05-01 16:26:07 +100029
30int of_n_addr_cells(struct device_node *np)
31{
32 const int *ip;
33
34 do {
35 if (np->parent)
36 np = np->parent;
37 ip = of_get_property(np, "#address-cells", NULL);
38 if (ip)
39 return *ip;
40 } while (np->parent);
41 /* No #address-cells property for the root node */
42 return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
43}
44EXPORT_SYMBOL(of_n_addr_cells);
45
46int of_n_size_cells(struct device_node *np)
47{
48 const int *ip;
49
50 do {
51 if (np->parent)
52 np = np->parent;
53 ip = of_get_property(np, "#size-cells", NULL);
54 if (ip)
55 return *ip;
56 } while (np->parent);
57 /* No #size-cells property for the root node */
58 return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
59}
60EXPORT_SYMBOL(of_n_size_cells);
61
Stephen Rothwell581b6052007-04-24 16:46:53 +100062struct property *of_find_property(const struct device_node *np,
63 const char *name,
64 int *lenp)
65{
66 struct property *pp;
67
Timur Tabi64e45662008-05-08 05:19:59 +100068 if (!np)
69 return NULL;
70
Stephen Rothwell581b6052007-04-24 16:46:53 +100071 read_lock(&devtree_lock);
72 for (pp = np->properties; pp != 0; pp = pp->next) {
73 if (of_prop_cmp(pp->name, name) == 0) {
74 if (lenp != 0)
75 *lenp = pp->length;
76 break;
77 }
78 }
79 read_unlock(&devtree_lock);
80
81 return pp;
82}
83EXPORT_SYMBOL(of_find_property);
84
Stephen Rothwell97e873e2007-05-01 16:26:07 +100085/*
86 * Find a property with a given name for a given node
87 * and return the value.
88 */
89const void *of_get_property(const struct device_node *np, const char *name,
90 int *lenp)
91{
92 struct property *pp = of_find_property(np, name, lenp);
93
94 return pp ? pp->value : NULL;
95}
96EXPORT_SYMBOL(of_get_property);
Stephen Rothwell0081cbc2007-05-01 16:29:19 +100097
98/** Checks if the given "compat" string matches one of the strings in
99 * the device's "compatible" property
100 */
101int of_device_is_compatible(const struct device_node *device,
102 const char *compat)
103{
104 const char* cp;
105 int cplen, l;
106
107 cp = of_get_property(device, "compatible", &cplen);
108 if (cp == NULL)
109 return 0;
110 while (cplen > 0) {
111 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
112 return 1;
113 l = strlen(cp) + 1;
114 cp += l;
115 cplen -= l;
116 }
117
118 return 0;
119}
120EXPORT_SYMBOL(of_device_is_compatible);
Stephen Rothwelle679c5f2007-04-24 17:16:16 +1000121
122/**
Josh Boyer834d97d2008-03-27 00:33:14 +1100123 * of_device_is_available - check if a device is available for use
124 *
125 * @device: Node to check for availability
126 *
127 * Returns 1 if the status property is absent or set to "okay" or "ok",
128 * 0 otherwise
129 */
130int of_device_is_available(const struct device_node *device)
131{
132 const char *status;
133 int statlen;
134
135 status = of_get_property(device, "status", &statlen);
136 if (status == NULL)
137 return 1;
138
139 if (statlen > 0) {
140 if (!strcmp(status, "okay") || !strcmp(status, "ok"))
141 return 1;
142 }
143
144 return 0;
145}
146EXPORT_SYMBOL(of_device_is_available);
147
148/**
Stephen Rothwelle679c5f2007-04-24 17:16:16 +1000149 * of_get_parent - Get a node's parent if any
150 * @node: Node to get parent
151 *
152 * Returns a node pointer with refcount incremented, use
153 * of_node_put() on it when done.
154 */
155struct device_node *of_get_parent(const struct device_node *node)
156{
157 struct device_node *np;
158
159 if (!node)
160 return NULL;
161
162 read_lock(&devtree_lock);
163 np = of_node_get(node->parent);
164 read_unlock(&devtree_lock);
165 return np;
166}
167EXPORT_SYMBOL(of_get_parent);
Stephen Rothwelld1cd3552007-04-24 17:21:29 +1000168
169/**
Michael Ellermanf4eb0102007-10-26 16:54:31 +1000170 * of_get_next_parent - Iterate to a node's parent
171 * @node: Node to get parent of
172 *
173 * This is like of_get_parent() except that it drops the
174 * refcount on the passed node, making it suitable for iterating
175 * through a node's parents.
176 *
177 * Returns a node pointer with refcount incremented, use
178 * of_node_put() on it when done.
179 */
180struct device_node *of_get_next_parent(struct device_node *node)
181{
182 struct device_node *parent;
183
184 if (!node)
185 return NULL;
186
187 read_lock(&devtree_lock);
188 parent = of_node_get(node->parent);
189 of_node_put(node);
190 read_unlock(&devtree_lock);
191 return parent;
192}
193
194/**
Stephen Rothwelld1cd3552007-04-24 17:21:29 +1000195 * of_get_next_child - Iterate a node childs
196 * @node: parent node
197 * @prev: previous child of the parent node, or NULL to get first
198 *
199 * Returns a node pointer with refcount incremented, use
200 * of_node_put() on it when done.
201 */
202struct device_node *of_get_next_child(const struct device_node *node,
203 struct device_node *prev)
204{
205 struct device_node *next;
206
207 read_lock(&devtree_lock);
208 next = prev ? prev->sibling : node->child;
209 for (; next; next = next->sibling)
210 if (of_node_get(next))
211 break;
212 of_node_put(prev);
213 read_unlock(&devtree_lock);
214 return next;
215}
216EXPORT_SYMBOL(of_get_next_child);
Stephen Rothwell1ef4d422007-04-24 17:57:33 +1000217
218/**
219 * of_find_node_by_path - Find a node matching a full OF path
220 * @path: The full path to match
221 *
222 * Returns a node pointer with refcount incremented, use
223 * of_node_put() on it when done.
224 */
225struct device_node *of_find_node_by_path(const char *path)
226{
227 struct device_node *np = allnodes;
228
229 read_lock(&devtree_lock);
230 for (; np; np = np->allnext) {
231 if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
232 && of_node_get(np))
233 break;
234 }
235 read_unlock(&devtree_lock);
236 return np;
237}
238EXPORT_SYMBOL(of_find_node_by_path);
239
240/**
241 * of_find_node_by_name - Find a node by its "name" property
242 * @from: The node to start searching from or NULL, the node
243 * you pass will not be searched, only the next one
244 * will; typically, you pass what the previous call
245 * returned. of_node_put() will be called on it
246 * @name: The name string to match against
247 *
248 * Returns a node pointer with refcount incremented, use
249 * of_node_put() on it when done.
250 */
251struct device_node *of_find_node_by_name(struct device_node *from,
252 const char *name)
253{
254 struct device_node *np;
255
256 read_lock(&devtree_lock);
257 np = from ? from->allnext : allnodes;
258 for (; np; np = np->allnext)
259 if (np->name && (of_node_cmp(np->name, name) == 0)
260 && of_node_get(np))
261 break;
262 of_node_put(from);
263 read_unlock(&devtree_lock);
264 return np;
265}
266EXPORT_SYMBOL(of_find_node_by_name);
267
268/**
269 * of_find_node_by_type - Find a node by its "device_type" property
270 * @from: The node to start searching from, or NULL to start searching
271 * the entire device tree. The node you pass will not be
272 * searched, only the next one will; typically, you pass
273 * what the previous call returned. of_node_put() will be
274 * called on from for you.
275 * @type: The type string to match against
276 *
277 * Returns a node pointer with refcount incremented, use
278 * of_node_put() on it when done.
279 */
280struct device_node *of_find_node_by_type(struct device_node *from,
281 const char *type)
282{
283 struct device_node *np;
284
285 read_lock(&devtree_lock);
286 np = from ? from->allnext : allnodes;
287 for (; np; np = np->allnext)
288 if (np->type && (of_node_cmp(np->type, type) == 0)
289 && of_node_get(np))
290 break;
291 of_node_put(from);
292 read_unlock(&devtree_lock);
293 return np;
294}
295EXPORT_SYMBOL(of_find_node_by_type);
296
297/**
298 * of_find_compatible_node - Find a node based on type and one of the
299 * tokens in its "compatible" property
300 * @from: The node to start searching from or NULL, the node
301 * you pass will not be searched, only the next one
302 * will; typically, you pass what the previous call
303 * returned. of_node_put() will be called on it
304 * @type: The type string to match "device_type" or NULL to ignore
305 * @compatible: The string to match to one of the tokens in the device
306 * "compatible" list.
307 *
308 * Returns a node pointer with refcount incremented, use
309 * of_node_put() on it when done.
310 */
311struct device_node *of_find_compatible_node(struct device_node *from,
312 const char *type, const char *compatible)
313{
314 struct device_node *np;
315
316 read_lock(&devtree_lock);
317 np = from ? from->allnext : allnodes;
318 for (; np; np = np->allnext) {
319 if (type
320 && !(np->type && (of_node_cmp(np->type, type) == 0)))
321 continue;
322 if (of_device_is_compatible(np, compatible) && of_node_get(np))
323 break;
324 }
325 of_node_put(from);
326 read_unlock(&devtree_lock);
327 return np;
328}
329EXPORT_SYMBOL(of_find_compatible_node);
Grant Likely283029d2008-01-09 06:20:40 +1100330
331/**
Michael Ellerman1e291b12008-11-12 18:54:42 +0000332 * of_find_node_with_property - Find a node which has a property with
333 * the given name.
334 * @from: The node to start searching from or NULL, the node
335 * you pass will not be searched, only the next one
336 * will; typically, you pass what the previous call
337 * returned. of_node_put() will be called on it
338 * @prop_name: The name of the property to look for.
339 *
340 * Returns a node pointer with refcount incremented, use
341 * of_node_put() on it when done.
342 */
343struct device_node *of_find_node_with_property(struct device_node *from,
344 const char *prop_name)
345{
346 struct device_node *np;
347 struct property *pp;
348
349 read_lock(&devtree_lock);
350 np = from ? from->allnext : allnodes;
351 for (; np; np = np->allnext) {
352 for (pp = np->properties; pp != 0; pp = pp->next) {
353 if (of_prop_cmp(pp->name, prop_name) == 0) {
354 of_node_get(np);
355 goto out;
356 }
357 }
358 }
359out:
360 of_node_put(from);
361 read_unlock(&devtree_lock);
362 return np;
363}
364EXPORT_SYMBOL(of_find_node_with_property);
365
366/**
Grant Likely283029d2008-01-09 06:20:40 +1100367 * of_match_node - Tell if an device_node has a matching of_match structure
368 * @matches: array of of device match structures to search in
369 * @node: the of device structure to match against
370 *
371 * Low level utility function used by device matching.
372 */
373const struct of_device_id *of_match_node(const struct of_device_id *matches,
374 const struct device_node *node)
375{
376 while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
377 int match = 1;
378 if (matches->name[0])
379 match &= node->name
380 && !strcmp(matches->name, node->name);
381 if (matches->type[0])
382 match &= node->type
383 && !strcmp(matches->type, node->type);
384 if (matches->compatible[0])
385 match &= of_device_is_compatible(node,
386 matches->compatible);
387 if (match)
388 return matches;
389 matches++;
390 }
391 return NULL;
392}
393EXPORT_SYMBOL(of_match_node);
394
395/**
396 * of_find_matching_node - Find a node based on an of_device_id match
397 * table.
398 * @from: The node to start searching from or NULL, the node
399 * you pass will not be searched, only the next one
400 * will; typically, you pass what the previous call
401 * returned. of_node_put() will be called on it
402 * @matches: array of of device match structures to search in
403 *
404 * Returns a node pointer with refcount incremented, use
405 * of_node_put() on it when done.
406 */
407struct device_node *of_find_matching_node(struct device_node *from,
408 const struct of_device_id *matches)
409{
410 struct device_node *np;
411
412 read_lock(&devtree_lock);
413 np = from ? from->allnext : allnodes;
414 for (; np; np = np->allnext) {
415 if (of_match_node(matches, np) && of_node_get(np))
416 break;
417 }
418 of_node_put(from);
419 read_unlock(&devtree_lock);
420 return np;
421}
422EXPORT_SYMBOL(of_find_matching_node);
Grant Likely3f07af42008-07-25 22:25:13 -0400423
424/**
425 * of_modalias_table: Table of explicit compatible ==> modalias mappings
426 *
427 * This table allows particulare compatible property values to be mapped
428 * to modalias strings. This is useful for busses which do not directly
429 * understand the OF device tree but are populated based on data contained
430 * within the device tree. SPI and I2C are the two current users of this
431 * table.
432 *
433 * In most cases, devices do not need to be listed in this table because
434 * the modalias value can be derived directly from the compatible table.
435 * However, if for any reason a value cannot be derived, then this table
436 * provides a method to override the implicit derivation.
437 *
438 * At the moment, a single table is used for all bus types because it is
439 * assumed that the data size is small and that the compatible values
440 * should already be distinct enough to differentiate between SPI, I2C
441 * and other devices.
442 */
443struct of_modalias_table {
444 char *of_device;
445 char *modalias;
446};
447static struct of_modalias_table of_modalias_table[] = {
Anton Vorontsov4c3ed7d2008-09-23 14:12:19 +0400448 { "fsl,mcu-mpc8349emitx", "mcu-mpc8349emitx" },
Anton Vorontsov3f1c6eb2009-03-31 15:24:38 -0700449 { "mmc-spi-slot", "mmc_spi" },
Anton Vorontsovbd78c332009-05-02 06:16:59 +0400450 { "stm,m25p40", "m25p80" },
Grant Likely3f07af42008-07-25 22:25:13 -0400451};
452
453/**
454 * of_modalias_node - Lookup appropriate modalias for a device node
455 * @node: pointer to a device tree node
456 * @modalias: Pointer to buffer that modalias value will be copied into
457 * @len: Length of modalias value
458 *
459 * Based on the value of the compatible property, this routine will determine
Grant Likely58f467c2008-10-08 05:05:29 +0000460 * an appropriate modalias value for a particular device tree node. Two
461 * separate methods are attempted to derive a modalias value.
Grant Likely3f07af42008-07-25 22:25:13 -0400462 *
463 * First method is to lookup the compatible value in of_modalias_table.
Grant Likely58f467c2008-10-08 05:05:29 +0000464 * Second is to strip off the manufacturer prefix from the first
465 * compatible entry and use the remainder as modalias
Grant Likely3f07af42008-07-25 22:25:13 -0400466 *
467 * This routine returns 0 on success
468 */
469int of_modalias_node(struct device_node *node, char *modalias, int len)
470{
471 int i, cplen;
472 const char *compatible;
473 const char *p;
474
475 /* 1. search for exception list entry */
476 for (i = 0; i < ARRAY_SIZE(of_modalias_table); i++) {
477 compatible = of_modalias_table[i].of_device;
478 if (!of_device_is_compatible(node, compatible))
479 continue;
480 strlcpy(modalias, of_modalias_table[i].modalias, len);
481 return 0;
482 }
483
484 compatible = of_get_property(node, "compatible", &cplen);
485 if (!compatible)
486 return -ENODEV;
487
Grant Likely58f467c2008-10-08 05:05:29 +0000488 /* 2. take first compatible entry and strip manufacturer */
Grant Likely3f07af42008-07-25 22:25:13 -0400489 p = strchr(compatible, ',');
490 if (!p)
491 return -ENODEV;
492 p++;
493 strlcpy(modalias, p, len);
494 return 0;
495}
496EXPORT_SYMBOL_GPL(of_modalias_node);
497
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000498/**
Grant Likely739649c2009-04-25 12:52:40 +0000499 * of_parse_phandle - Resolve a phandle property to a device_node pointer
500 * @np: Pointer to device node holding phandle property
501 * @phandle_name: Name of property holding a phandle value
502 * @index: For properties holding a table of phandles, this is the index into
503 * the table
504 *
505 * Returns the device_node pointer with refcount incremented. Use
506 * of_node_put() on it when done.
507 */
508struct device_node *
509of_parse_phandle(struct device_node *np, const char *phandle_name, int index)
510{
511 const phandle *phandle;
512 int size;
513
514 phandle = of_get_property(np, phandle_name, &size);
515 if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
516 return NULL;
517
518 return of_find_node_by_phandle(phandle[index]);
519}
520EXPORT_SYMBOL(of_parse_phandle);
521
522/**
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000523 * of_parse_phandles_with_args - Find a node pointed by phandle in a list
524 * @np: pointer to a device tree node containing a list
525 * @list_name: property name that contains a list
526 * @cells_name: property name that specifies phandles' arguments count
527 * @index: index of a phandle to parse out
Anton Vorontsov7736a3d2008-12-05 08:15:46 +0000528 * @out_node: optional pointer to device_node struct pointer (will be filled)
529 * @out_args: optional pointer to arguments pointer (will be filled)
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000530 *
531 * This function is useful to parse lists of phandles and their arguments.
532 * Returns 0 on success and fills out_node and out_args, on error returns
533 * appropriate errno value.
534 *
535 * Example:
536 *
537 * phandle1: node1 {
538 * #list-cells = <2>;
539 * }
540 *
541 * phandle2: node2 {
542 * #list-cells = <1>;
543 * }
544 *
545 * node3 {
546 * list = <&phandle1 1 2 &phandle2 3>;
547 * }
548 *
549 * To get a device_node of the `node2' node you may call this:
550 * of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args);
551 */
552int of_parse_phandles_with_args(struct device_node *np, const char *list_name,
553 const char *cells_name, int index,
554 struct device_node **out_node,
555 const void **out_args)
556{
557 int ret = -EINVAL;
558 const u32 *list;
559 const u32 *list_end;
560 int size;
561 int cur_index = 0;
562 struct device_node *node = NULL;
Anton Vorontsov7736a3d2008-12-05 08:15:46 +0000563 const void *args = NULL;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000564
565 list = of_get_property(np, list_name, &size);
566 if (!list) {
567 ret = -ENOENT;
568 goto err0;
569 }
570 list_end = list + size / sizeof(*list);
571
572 while (list < list_end) {
573 const u32 *cells;
574 const phandle *phandle;
575
Anton Vorontsovc1bb7c62008-12-05 08:15:39 +0000576 phandle = list++;
577 args = list;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000578
579 /* one cell hole in the list = <>; */
Anton Vorontsovc1bb7c62008-12-05 08:15:39 +0000580 if (!*phandle)
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000581 goto next;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000582
583 node = of_find_node_by_phandle(*phandle);
584 if (!node) {
585 pr_debug("%s: could not find phandle\n",
586 np->full_name);
587 goto err0;
588 }
589
590 cells = of_get_property(node, cells_name, &size);
591 if (!cells || size != sizeof(*cells)) {
592 pr_debug("%s: could not get %s for %s\n",
593 np->full_name, cells_name, node->full_name);
594 goto err1;
595 }
596
Anton Vorontsovc1bb7c62008-12-05 08:15:39 +0000597 list += *cells;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000598 if (list > list_end) {
599 pr_debug("%s: insufficient arguments length\n",
600 np->full_name);
601 goto err1;
602 }
603next:
604 if (cur_index == index)
605 break;
606
607 of_node_put(node);
608 node = NULL;
Anton Vorontsov7736a3d2008-12-05 08:15:46 +0000609 args = NULL;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000610 cur_index++;
611 }
612
613 if (!node) {
Anton Vorontsov7736a3d2008-12-05 08:15:46 +0000614 /*
615 * args w/o node indicates that the loop above has stopped at
616 * the 'hole' cell. Report this differently.
617 */
618 if (args)
619 ret = -EEXIST;
620 else
621 ret = -ENOENT;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000622 goto err0;
623 }
624
Anton Vorontsov7736a3d2008-12-05 08:15:46 +0000625 if (out_node)
626 *out_node = node;
627 if (out_args)
628 *out_args = args;
Anton Vorontsov64b60e02008-10-10 04:43:17 +0000629
630 return 0;
631err1:
632 of_node_put(node);
633err0:
634 pr_debug("%s failed with status %d\n", __func__, ret);
635 return ret;
636}
637EXPORT_SYMBOL(of_parse_phandles_with_args);