summaryrefslogtreecommitdiff
path: root/drivers/of/base.c
blob: 69f85c07d17fc24718861b41618c6a8c0c493183 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
/*
 * Procedures for creating, accessing and interpreting the device tree.
 *
 * Paul Mackerras	August 1996.
 * Copyright (C) 1996-2005 Paul Mackerras.
 *
 *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
 *    {engebret|bergner}@us.ibm.com
 *
 *  Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
 *
 *  Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell.
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */
#include <linux/module.h>
#include <linux/of.h>
#include <linux/spinlock.h>

struct device_node *allnodes;

/* use when traversing tree through the allnext, child, sibling,
 * or parent members of struct device_node.
 */
DEFINE_RWLOCK(devtree_lock);

int of_n_addr_cells(struct device_node *np)
{
	const int *ip;

	do {
		if (np->parent)
			np = np->parent;
		ip = of_get_property(np, "#address-cells", NULL);
		if (ip)
			return *ip;
	} while (np->parent);
	/* No #address-cells property for the root node */
	return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
}
EXPORT_SYMBOL(of_n_addr_cells);

int of_n_size_cells(struct device_node *np)
{
	const int *ip;

	do {
		if (np->parent)
			np = np->parent;
		ip = of_get_property(np, "#size-cells", NULL);
		if (ip)
			return *ip;
	} while (np->parent);
	/* No #size-cells property for the root node */
	return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
}
EXPORT_SYMBOL(of_n_size_cells);

struct property *of_find_property(const struct device_node *np,
				  const char *name,
				  int *lenp)
{
	struct property *pp;

	if (!np)
		return NULL;

	read_lock(&devtree_lock);
	for (pp = np->properties; pp != 0; pp = pp->next) {
		if (of_prop_cmp(pp->name, name) == 0) {
			if (lenp != 0)
				*lenp = pp->length;
			break;
		}
	}
	read_unlock(&devtree_lock);

	return pp;
}
EXPORT_SYMBOL(of_find_property);

/*
 * Find a property with a given name for a given node
 * and return the value.
 */
const void *of_get_property(const struct device_node *np, const char *name,
			 int *lenp)
{
	struct property *pp = of_find_property(np, name, lenp);

	return pp ? pp->value : NULL;
}
EXPORT_SYMBOL(of_get_property);

/** Checks if the given "compat" string matches one of the strings in
 * the device's "compatible" property
 */
int of_device_is_compatible(const struct device_node *device,
		const char *compat)
{
	const char* cp;
	int cplen, l;

	cp = of_get_property(device, "compatible", &cplen);
	if (cp == NULL)
		return 0;
	while (cplen > 0) {
		if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
			return 1;
		l = strlen(cp) + 1;
		cp += l;
		cplen -= l;
	}

	return 0;
}
EXPORT_SYMBOL(of_device_is_compatible);

/**
 *  of_device_is_available - check if a device is available for use
 *
 *  @device: Node to check for availability
 *
 *  Returns 1 if the status property is absent or set to "okay" or "ok",
 *  0 otherwise
 */
int of_device_is_available(const struct device_node *device)
{
	const char *status;
	int statlen;

	status = of_get_property(device, "status", &statlen);
	if (status == NULL)
		return 1;

	if (statlen > 0) {
		if (!strcmp(status, "okay") || !strcmp(status, "ok"))
			return 1;
	}

	return 0;
}
EXPORT_SYMBOL(of_device_is_available);

/**
 *	of_get_parent - Get a node's parent if any
 *	@node:	Node to get parent
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_get_parent(const struct device_node *node)
{
	struct device_node *np;

	if (!node)
		return NULL;

	read_lock(&devtree_lock);
	np = of_node_get(node->parent);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_get_parent);

/**
 *	of_get_next_parent - Iterate to a node's parent
 *	@node:	Node to get parent of
 *
 * 	This is like of_get_parent() except that it drops the
 * 	refcount on the passed node, making it suitable for iterating
 * 	through a node's parents.
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_get_next_parent(struct device_node *node)
{
	struct device_node *parent;

	if (!node)
		return NULL;

	read_lock(&devtree_lock);
	parent = of_node_get(node->parent);
	of_node_put(node);
	read_unlock(&devtree_lock);
	return parent;
}

/**
 *	of_get_next_child - Iterate a node childs
 *	@node:	parent node
 *	@prev:	previous child of the parent node, or NULL to get first
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_get_next_child(const struct device_node *node,
	struct device_node *prev)
{
	struct device_node *next;

	read_lock(&devtree_lock);
	next = prev ? prev->sibling : node->child;
	for (; next; next = next->sibling)
		if (of_node_get(next))
			break;
	of_node_put(prev);
	read_unlock(&devtree_lock);
	return next;
}
EXPORT_SYMBOL(of_get_next_child);

/**
 *	of_find_node_by_path - Find a node matching a full OF path
 *	@path:	The full path to match
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_by_path(const char *path)
{
	struct device_node *np = allnodes;

	read_lock(&devtree_lock);
	for (; np; np = np->allnext) {
		if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
		    && of_node_get(np))
			break;
	}
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_node_by_path);

/**
 *	of_find_node_by_name - Find a node by its "name" property
 *	@from:	The node to start searching from or NULL, the node
 *		you pass will not be searched, only the next one
 *		will; typically, you pass what the previous call
 *		returned. of_node_put() will be called on it
 *	@name:	The name string to match against
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_by_name(struct device_node *from,
	const char *name)
{
	struct device_node *np;

	read_lock(&devtree_lock);
	np = from ? from->allnext : allnodes;
	for (; np; np = np->allnext)
		if (np->name && (of_node_cmp(np->name, name) == 0)
		    && of_node_get(np))
			break;
	of_node_put(from);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_node_by_name);

/**
 *	of_find_node_by_type - Find a node by its "device_type" property
 *	@from:	The node to start searching from, or NULL to start searching
 *		the entire device tree. The node you pass will not be
 *		searched, only the next one will; typically, you pass
 *		what the previous call returned. of_node_put() will be
 *		called on from for you.
 *	@type:	The type string to match against
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_by_type(struct device_node *from,
	const char *type)
{
	struct device_node *np;

	read_lock(&devtree_lock);
	np = from ? from->allnext : allnodes;
	for (; np; np = np->allnext)
		if (np->type && (of_node_cmp(np->type, type) == 0)
		    && of_node_get(np))
			break;
	of_node_put(from);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_node_by_type);

/**
 *	of_find_compatible_node - Find a node based on type and one of the
 *                                tokens in its "compatible" property
 *	@from:		The node to start searching from or NULL, the node
 *			you pass will not be searched, only the next one
 *			will; typically, you pass what the previous call
 *			returned. of_node_put() will be called on it
 *	@type:		The type string to match "device_type" or NULL to ignore
 *	@compatible:	The string to match to one of the tokens in the device
 *			"compatible" list.
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_compatible_node(struct device_node *from,
	const char *type, const char *compatible)
{
	struct device_node *np;

	read_lock(&devtree_lock);
	np = from ? from->allnext : allnodes;
	for (; np; np = np->allnext) {
		if (type
		    && !(np->type && (of_node_cmp(np->type, type) == 0)))
			continue;
		if (of_device_is_compatible(np, compatible) && of_node_get(np))
			break;
	}
	of_node_put(from);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_compatible_node);

/**
 *	of_find_node_with_property - Find a node which has a property with
 *                                   the given name.
 *	@from:		The node to start searching from or NULL, the node
 *			you pass will not be searched, only the next one
 *			will; typically, you pass what the previous call
 *			returned. of_node_put() will be called on it
 *	@prop_name:	The name of the property to look for.
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_with_property(struct device_node *from,
	const char *prop_name)
{
	struct device_node *np;
	struct property *pp;

	read_lock(&devtree_lock);
	np = from ? from->allnext : allnodes;
	for (; np; np = np->allnext) {
		for (pp = np->properties; pp != 0; pp = pp->next) {
			if (of_prop_cmp(pp->name, prop_name) == 0) {
				of_node_get(np);
				goto out;
			}
		}
	}
out:
	of_node_put(from);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_node_with_property);

/**
 * of_match_node - Tell if an device_node has a matching of_match structure
 *	@matches:	array of of device match structures to search in
 *	@node:		the of device structure to match against
 *
 *	Low level utility function used by device matching.
 */
const struct of_device_id *of_match_node(const struct of_device_id *matches,
					 const struct device_node *node)
{
	while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
		int match = 1;
		if (matches->name[0])
			match &= node->name
				&& !strcmp(matches->name, node->name);
		if (matches->type[0])
			match &= node->type
				&& !strcmp(matches->type, node->type);
		if (matches->compatible[0])
			match &= of_device_is_compatible(node,
						matches->compatible);
		if (match)
			return matches;
		matches++;
	}
	return NULL;
}
EXPORT_SYMBOL(of_match_node);

/**
 *	of_find_matching_node - Find a node based on an of_device_id match
 *				table.
 *	@from:		The node to start searching from or NULL, the node
 *			you pass will not be searched, only the next one
 *			will; typically, you pass what the previous call
 *			returned. of_node_put() will be called on it
 *	@matches:	array of of device match structures to search in
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_matching_node(struct device_node *from,
					  const struct of_device_id *matches)
{
	struct device_node *np;

	read_lock(&devtree_lock);
	np = from ? from->allnext : allnodes;
	for (; np; np = np->allnext) {
		if (of_match_node(matches, np) && of_node_get(np))
			break;
	}
	of_node_put(from);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_matching_node);

/**
 * of_modalias_table: Table of explicit compatible ==> modalias mappings
 *
 * This table allows particulare compatible property values to be mapped
 * to modalias strings.  This is useful for busses which do not directly
 * understand the OF device tree but are populated based on data contained
 * within the device tree.  SPI and I2C are the two current users of this
 * table.
 *
 * In most cases, devices do not need to be listed in this table because
 * the modalias value can be derived directly from the compatible table.
 * However, if for any reason a value cannot be derived, then this table
 * provides a method to override the implicit derivation.
 *
 * At the moment, a single table is used for all bus types because it is
 * assumed that the data size is small and that the compatible values
 * should already be distinct enough to differentiate between SPI, I2C
 * and other devices.
 */
struct of_modalias_table {
	char *of_device;
	char *modalias;
};
static struct of_modalias_table of_modalias_table[] = {
	{ "fsl,mcu-mpc8349emitx", "mcu-mpc8349emitx" },
	{ "mmc-spi-slot", "mmc_spi" },
	{ "stm,m25p40", "m25p80" },
};

/**
 * of_modalias_node - Lookup appropriate modalias for a device node
 * @node:	pointer to a device tree node
 * @modalias:	Pointer to buffer that modalias value will be copied into
 * @len:	Length of modalias value
 *
 * Based on the value of the compatible property, this routine will determine
 * an appropriate modalias value for a particular device tree node.  Two
 * separate methods are attempted to derive a modalias value.
 *
 * First method is to lookup the compatible value in of_modalias_table.
 * Second is to strip off the manufacturer prefix from the first
 * compatible entry and use the remainder as modalias
 *
 * This routine returns 0 on success
 */
int of_modalias_node(struct device_node *node, char *modalias, int len)
{
	int i, cplen;
	const char *compatible;
	const char *p;

	/* 1. search for exception list entry */
	for (i = 0; i < ARRAY_SIZE(of_modalias_table); i++) {
		compatible = of_modalias_table[i].of_device;
		if (!of_device_is_compatible(node, compatible))
			continue;
		strlcpy(modalias, of_modalias_table[i].modalias, len);
		return 0;
	}

	compatible = of_get_property(node, "compatible", &cplen);
	if (!compatible)
		return -ENODEV;

	/* 2. take first compatible entry and strip manufacturer */
	p = strchr(compatible, ',');
	if (!p)
		return -ENODEV;
	p++;
	strlcpy(modalias, p, len);
	return 0;
}
EXPORT_SYMBOL_GPL(of_modalias_node);

/**
 * of_parse_phandle - Resolve a phandle property to a device_node pointer
 * @np: Pointer to device node holding phandle property
 * @phandle_name: Name of property holding a phandle value
 * @index: For properties holding a table of phandles, this is the index into
 *         the table
 *
 * Returns the device_node pointer with refcount incremented.  Use
 * of_node_put() on it when done.
 */
struct device_node *
of_parse_phandle(struct device_node *np, const char *phandle_name, int index)
{
	const phandle *phandle;
	int size;

	phandle = of_get_property(np, phandle_name, &size);
	if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
		return NULL;

	return of_find_node_by_phandle(phandle[index]);
}
EXPORT_SYMBOL(of_parse_phandle);

/**
 * of_parse_phandles_with_args - Find a node pointed by phandle in a list
 * @np:		pointer to a device tree node containing a list
 * @list_name:	property name that contains a list
 * @cells_name:	property name that specifies phandles' arguments count
 * @index:	index of a phandle to parse out
 * @out_node:	optional pointer to device_node struct pointer (will be filled)
 * @out_args:	optional pointer to arguments pointer (will be filled)
 *
 * This function is useful to parse lists of phandles and their arguments.
 * Returns 0 on success and fills out_node and out_args, on error returns
 * appropriate errno value.
 *
 * Example:
 *
 * phandle1: node1 {
 * 	#list-cells = <2>;
 * }
 *
 * phandle2: node2 {
 * 	#list-cells = <1>;
 * }
 *
 * node3 {
 * 	list = <&phandle1 1 2 &phandle2 3>;
 * }
 *
 * To get a device_node of the `node2' node you may call this:
 * of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args);
 */
int of_parse_phandles_with_args(struct device_node *np, const char *list_name,
				const char *cells_name, int index,
				struct device_node **out_node,
				const void **out_args)
{
	int ret = -EINVAL;
	const u32 *list;
	const u32 *list_end;
	int size;
	int cur_index = 0;
	struct device_node *node = NULL;
	const void *args = NULL;

	list = of_get_property(np, list_name, &size);
	if (!list) {
		ret = -ENOENT;
		goto err0;
	}
	list_end = list + size / sizeof(*list);

	while (list < list_end) {
		const u32 *cells;
		const phandle *phandle;

		phandle = list++;
		args = list;

		/* one cell hole in the list = <>; */
		if (!*phandle)
			goto next;

		node = of_find_node_by_phandle(*phandle);
		if (!node) {
			pr_debug("%s: could not find phandle\n",
				 np->full_name);
			goto err0;
		}

		cells = of_get_property(node, cells_name, &size);
		if (!cells || size != sizeof(*cells)) {
			pr_debug("%s: could not get %s for %s\n",
				 np->full_name, cells_name, node->full_name);
			goto err1;
		}

		list += *cells;
		if (list > list_end) {
			pr_debug("%s: insufficient arguments length\n",
				 np->full_name);
			goto err1;
		}
next:
		if (cur_index == index)
			break;

		of_node_put(node);
		node = NULL;
		args = NULL;
		cur_index++;
	}

	if (!node) {
		/*
		 * args w/o node indicates that the loop above has stopped at
		 * the 'hole' cell. Report this differently.
		 */
		if (args)
			ret = -EEXIST;
		else
			ret = -ENOENT;
		goto err0;
	}

	if (out_node)
		*out_node = node;
	if (out_args)
		*out_args = args;

	return 0;
err1:
	of_node_put(node);
err0:
	pr_debug("%s failed with status %d\n", __func__, ret);
	return ret;
}
EXPORT_SYMBOL(of_parse_phandles_with_args);