~funderscore blog cgit wiki get in touch
aboutsummaryrefslogtreecommitdiff
blob: 57f10445b1221df353fc8f452ca45cba865c53d8 (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
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
// SPDX-License-Identifier: GPL-2.0+
/*
 * Originally from Linux v4.9
 * 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 and
 * Grant Likely.
 *
 * Modified for U-Boot
 * Copyright (c) 2017 Google, Inc
 *
 * This file follows drivers/of/base.c with functions in the same order as the
 * Linux version.
 */

#include <common.h>
#include <log.h>
#include <malloc.h>
#include <asm/global_data.h>
#include <linux/bug.h>
#include <linux/libfdt.h>
#include <dm/of_access.h>
#include <linux/ctype.h>
#include <linux/err.h>
#include <linux/ioport.h>

DECLARE_GLOBAL_DATA_PTR;

/* list of struct alias_prop aliases */
static LIST_HEAD(aliases_lookup);

/* "/aliaes" node */
static struct device_node *of_aliases;

/* "/chosen" node */
static struct device_node *of_chosen;

/* node pointed to by the stdout-path alias */
static struct device_node *of_stdout;

/* pointer to options given after the alias (separated by :) or NULL if none */
static const char *of_stdout_options;

/**
 * struct alias_prop - Alias property in 'aliases' node
 *
 * The structure represents one alias property of 'aliases' node as
 * an entry in aliases_lookup list.
 *
 * @link:	List node to link the structure in aliases_lookup list
 * @alias:	Alias property name
 * @np:		Pointer to device_node that the alias stands for
 * @id:		Index value from end of alias name
 * @stem:	Alias string without the index
 */
struct alias_prop {
	struct list_head link;
	const char *alias;
	struct device_node *np;
	int id;
	char stem[0];
};

int of_n_addr_cells(const struct device_node *np)
{
	const __be32 *ip;

	do {
		if (np->parent)
			np = np->parent;
		ip = of_get_property(np, "#address-cells", NULL);
		if (ip)
			return be32_to_cpup(ip);
	} while (np->parent);

	/* No #address-cells property for the root node */
	return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
}

int of_n_size_cells(const struct device_node *np)
{
	const __be32 *ip;

	do {
		if (np->parent)
			np = np->parent;
		ip = of_get_property(np, "#size-cells", NULL);
		if (ip)
			return be32_to_cpup(ip);
	} while (np->parent);

	/* No #size-cells property for the root node */
	return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
}

int of_simple_addr_cells(const struct device_node *np)
{
	const __be32 *ip;

	ip = of_get_property(np, "#address-cells", NULL);
	if (ip)
		return be32_to_cpup(ip);

	/* Return a default of 2 to match fdt_address_cells()*/
	return 2;
}

int of_simple_size_cells(const struct device_node *np)
{
	const __be32 *ip;

	ip = of_get_property(np, "#size-cells", NULL);
	if (ip)
		return be32_to_cpup(ip);

	/* Return a default of 2 to match fdt_size_cells()*/
	return 2;
}

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

	if (!np)
		return NULL;

	for (pp = np->properties; pp; pp = pp->next) {
		if (strcmp(pp->name, name) == 0) {
			if (lenp)
				*lenp = pp->length;
			break;
		}
	}
	if (!pp && lenp)
		*lenp = -FDT_ERR_NOTFOUND;

	return pp;
}

struct device_node *of_find_all_nodes(struct device_node *prev)
{
	struct device_node *np;

	if (!prev) {
		np = gd->of_root;
	} else if (prev->child) {
		np = prev->child;
	} else {
		/*
		 * Walk back up looking for a sibling, or the end of the
		 * structure
		 */
		np = prev;
		while (np->parent && !np->sibling)
			np = np->parent;
		np = np->sibling; /* Might be null at the end of the tree */
	}

	return np;
}

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;
}

const struct property *of_get_first_property(const struct device_node *np)
{
	if (!np)
		return NULL;

	return  np->properties;
}

const struct property *of_get_next_property(const struct device_node *np,
					    const struct property *property)
{
	if (!np)
		return NULL;

	return property->next;
}

const void *of_get_property_by_prop(const struct device_node *np,
				    const struct property *property,
				    const char **name,
				    int *lenp)
{
	if (!np || !property)
		return NULL;
	if (name)
		*name = property->name;
	if (lenp)
		*lenp = property->length;

	return property->value;
}

static const char *of_prop_next_string(struct property *prop, const char *cur)
{
	const void *curv = cur;

	if (!prop)
		return NULL;

	if (!cur)
		return prop->value;

	curv += strlen(cur) + 1;
	if (curv >= prop->value + prop->length)
		return NULL;

	return curv;
}

int of_device_is_compatible(const struct device_node *device,
			    const char *compat, const char *type,
			    const char *name)
{
	struct property *prop;
	const char *cp;
	int index = 0, score = 0;

	/* Compatible match has highest priority */
	if (compat && compat[0]) {
		prop = of_find_property(device, "compatible", NULL);
		for (cp = of_prop_next_string(prop, NULL); cp;
		     cp = of_prop_next_string(prop, cp), index++) {
			if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
				score = INT_MAX/2 - (index << 2);
				break;
			}
		}
		if (!score)
			return 0;
	}

	/* Matching type is better than matching name */
	if (type && type[0]) {
		if (!device->type || of_node_cmp(type, device->type))
			return 0;
		score += 2;
	}

	/* Matching name is a bit better than not */
	if (name && name[0]) {
		if (!device->name || of_node_cmp(name, device->name))
			return 0;
		score++;
	}

	return score;
}

bool of_device_is_available(const struct device_node *device)
{
	const char *status;
	int statlen;

	if (!device)
		return false;

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

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

	return false;
}

struct device_node *of_get_parent(const struct device_node *node)
{
	const struct device_node *np;

	if (!node)
		return NULL;

	np = of_node_get(node->parent);

	return (struct device_node *)np;
}

static struct device_node *__of_get_next_child(const struct device_node *node,
					       struct device_node *prev)
{
	struct device_node *next;

	if (!node)
		return NULL;

	next = prev ? prev->sibling : node->child;
	/*
	 * coverity[dead_error_line : FALSE]
	 * Dead code here since our current implementation of of_node_get()
	 * always returns NULL (Coverity CID 163245). But we leave it as is
	 * since we may want to implement get/put later.
	 */
	for (; next; next = next->sibling)
		if (of_node_get(next))
			break;
	of_node_put(prev);
	return next;
}

#define __for_each_child_of_node(parent, child) \
	for (child = __of_get_next_child(parent, NULL); child != NULL; \
	     child = __of_get_next_child(parent, child))

static struct device_node *__of_find_node_by_path(struct device_node *parent,
						  const char *path)
{
	struct device_node *child;
	int len;

	len = strcspn(path, "/:");
	if (!len)
		return NULL;

	__for_each_child_of_node(parent, child) {
		const char *name = strrchr(child->full_name, '/');

		name++;
		if (strncmp(path, name, len) == 0 && (strlen(name) == len))
			return child;
	}
	return NULL;
}

#define for_each_property_of_node(dn, pp) \
	for (pp = dn->properties; pp != NULL; pp = pp->next)

struct device_node *of_find_node_opts_by_path(struct device_node *root,
					      const char *path,
					      const char **opts)
{
	struct device_node *np = NULL;
	struct property *pp;
	const char *separator = strchr(path, ':');

	if (!root)
		root = gd->of_root;
	if (opts)
		*opts = separator ? separator + 1 : NULL;

	if (strcmp(path, "/") == 0)
		return of_node_get(root);

	/* The path could begin with an alias */
	if (*path != '/') {
		int len;
		const char *p = separator;

		/* Only allow alias processing on the control FDT */
		if (root != gd->of_root)
			return NULL;
		if (!p)
			p = strchrnul(path, '/');
		len = p - path;

		/* of_aliases must not be NULL */
		if (!of_aliases)
			return NULL;

		for_each_property_of_node(of_aliases, pp) {
			if (strlen(pp->name) == len && !strncmp(pp->name, path,
								len)) {
				np = of_find_node_by_path(pp->value);
				break;
			}
		}
		if (!np)
			return NULL;
		path = p;
	}

	/* Step down the tree matching path components */
	if (!np)
		np = of_node_get(root);
	while (np && *path == '/') {
		struct device_node *tmp = np;

		path++; /* Increment past '/' delimiter */
		np = __of_find_node_by_path(np, path);
		of_node_put(tmp);
		path = strchrnul(path, '/');
		if (separator && separator < path)
			break;
	}

	return np;
}

struct device_node *of_find_compatible_node(struct device_node *from,
		const char *type, const char *compatible)
{
	struct device_node *np;

	for_each_of_allnodes_from(from, np)
		if (of_device_is_compatible(np, compatible, type, NULL) &&
		    of_node_get(np))
			break;
	of_node_put(from);

	return np;
}

static int of_device_has_prop_value(const struct device_node *device,
				    const char *propname, const void *propval,
				    int proplen)
{
	struct property *prop = of_find_property(device, propname, NULL);

	if (!prop || !prop->value || prop->length != proplen)
		return 0;
	return !memcmp(prop->value, propval, proplen);
}

struct device_node *of_find_node_by_prop_value(struct device_node *from,
					       const char *propname,
					       const void *propval, int proplen)
{
	struct device_node *np;

	for_each_of_allnodes_from(from, np) {
		if (of_device_has_prop_value(np, propname, propval, proplen) &&
		    of_node_get(np))
			break;
	}
	of_node_put(from);

	return np;
}

struct device_node *of_find_node_by_phandle(struct device_node *root,
					    phandle handle)
{
	struct device_node *np;

	if (!handle)
		return NULL;

	for_each_of_allnodes_from(root, np)
		if (np->phandle == handle)
			break;
	(void)of_node_get(np);

	return np;
}

/**
 * of_find_property_value_of_size() - find property of given size
 *
 * Search for a property in a device node and validate the requested size.
 *
 * @np:		device node from which the property value is to be read.
 * @propname:	name of the property to be searched.
 * @len:	requested length of property value
 *
 * Return: the property value on success, -EINVAL if the property does not
 * exist and -EOVERFLOW if the property data isn't large enough.
 */
static void *of_find_property_value_of_size(const struct device_node *np,
					    const char *propname, u32 len)
{
	struct property *prop = of_find_property(np, propname, NULL);

	if (!prop)
		return ERR_PTR(-EINVAL);
	if (len > prop->length)
		return ERR_PTR(-EOVERFLOW);

	return prop->value;
}

int of_read_u8(const struct device_node *np, const char *propname, u8 *outp)
{
	const u8 *val;

	debug("%s: %s: ", __func__, propname);
	if (!np)
		return -EINVAL;
	val = of_find_property_value_of_size(np, propname, sizeof(*outp));
	if (IS_ERR(val)) {
		debug("(not found)\n");
		return PTR_ERR(val);
	}

	*outp = *val;
	debug("%#x (%d)\n", *outp, *outp);

	return 0;
}

int of_read_u16(const struct device_node *np, const char *propname, u16 *outp)
{
	const __be16 *val;

	debug("%s: %s: ", __func__, propname);
	if (!np)
		return -EINVAL;
	val = of_find_property_value_of_size(np, propname, sizeof(*outp));
	if (IS_ERR(val)) {
		debug("(not found)\n");
		return PTR_ERR(val);
	}

	*outp = be16_to_cpup(val);
	debug("%#x (%d)\n", *outp, *outp);

	return 0;
}

int of_read_u32(const struct device_node *np, const char *propname, u32 *outp)
{
	return of_read_u32_index(np, propname, 0, outp);
}

int of_read_u32_array(const struct device_node *np, const char *propname,
		      u32 *out_values, size_t sz)
{
	const __be32 *val;

	debug("%s: %s: ", __func__, propname);
	val = of_find_property_value_of_size(np, propname,
					     sz * sizeof(*out_values));

	if (IS_ERR(val))
		return PTR_ERR(val);

	debug("size %zd\n", sz);
	while (sz--)
		*out_values++ = be32_to_cpup(val++);

	return 0;
}

int of_read_u32_index(const struct device_node *np, const char *propname,
		      int index, u32 *outp)
{
	const __be32 *val;

	debug("%s: %s: ", __func__, propname);
	if (!np)
		return -EINVAL;

	val = of_find_property_value_of_size(np, propname,
					     sizeof(*outp) * (index + 1));
	if (IS_ERR(val)) {
		debug("(not found)\n");
		return PTR_ERR(val);
	}

	*outp = be32_to_cpup(val + index);
	debug("%#x (%d)\n", *outp, *outp);

	return 0;
}

int of_read_u64(const struct device_node *np, const char *propname, u64 *outp)
{
	const __be64 *val;

	debug("%s: %s: ", __func__, propname);
	if (!np)
		return -EINVAL;
	val = of_find_property_value_of_size(np, propname, sizeof(*outp));
	if (IS_ERR(val)) {
		debug("(not found)\n");
		return PTR_ERR(val);
	}

	*outp = be64_to_cpup(val);
	debug("%#llx (%lld)\n", (unsigned long long)*outp,
              (unsigned long long)*outp);

	return 0;
}

int of_property_match_string(const struct device_node *np, const char *propname,
			     const char *string)
{
	int len = 0;
	const struct property *prop = of_find_property(np, propname, &len);
	size_t l;
	int i;
	const char *p, *end;

	if (!prop && len == -FDT_ERR_NOTFOUND)
		return -ENOENT;
	if (!prop)
		return -EINVAL;
	if (!prop->value)
		return -ENODATA;

	p = prop->value;
	end = p + prop->length;

	for (i = 0; p < end; i++, p += l) {
		l = strnlen(p, end - p) + 1;
		if (p + l > end)
			return -EILSEQ;
		debug("comparing %s with %s\n", string, p);
		if (strcmp(string, p) == 0)
			return i; /* Found it; return index */
	}
	return -ENODATA;
}

/**
 * of_property_read_string_helper() - Utility helper for parsing string properties
 * @np:		device node from which the property value is to be read.
 * @propname:	name of the property to be searched.
 * @out_strs:	output array of string pointers.
 * @sz:		number of array elements to read.
 * @skip:	Number of strings to skip over at beginning of list (cannot be
 *	negative)
 *
 * Don't call this function directly. It is a utility helper for the
 * of_property_read_string*() family of functions.
 */
int of_property_read_string_helper(const struct device_node *np,
				   const char *propname, const char **out_strs,
				   size_t sz, int skip)
{
	const struct property *prop = of_find_property(np, propname, NULL);
	int l = 0, i = 0;
	const char *p, *end;

	if (!prop)
		return -EINVAL;
	if (!prop->value)
		return -ENODATA;
	p = prop->value;
	end = p + prop->length;

	for (i = 0; p < end && (!out_strs || i < skip + sz); i++, p += l) {
		l = strnlen(p, end - p) + 1;
		if (p + l > end)
			return -EILSEQ;
		if (out_strs && i >= skip)
			*out_strs++ = p;
	}
	i -= skip;
	return i <= 0 ? -ENODATA : i;
}

static int __of_parse_phandle_with_args(const struct device_node *np,
					const char *list_name,
					const char *cells_name,
					int cell_count, int index,
					struct of_phandle_args *out_args)
{
	const __be32 *list, *list_end;
	int rc = 0, cur_index = 0;
	uint32_t count;
	struct device_node *node = NULL;
	phandle phandle;
	int size;

	/* Retrieve the phandle list property */
	list = of_get_property(np, list_name, &size);
	if (!list)
		return -ENOENT;
	list_end = list + size / sizeof(*list);

	/* Loop over the phandles until all the requested entry is found */
	while (list < list_end) {
		rc = -EINVAL;
		count = 0;

		/*
		 * If phandle is 0, then it is an empty entry with no
		 * arguments.  Skip forward to the next entry.
		 */
		phandle = be32_to_cpup(list++);
		if (phandle) {
			/*
			 * Find the provider node and parse the #*-cells
			 * property to determine the argument length.
			 *
			 * This is not needed if the cell count is hard-coded
			 * (i.e. cells_name not set, but cell_count is set),
			 * except when we're going to return the found node
			 * below.
			 */
			if (cells_name || cur_index == index) {
				node = of_find_node_by_phandle(NULL, phandle);
				if (!node) {
					debug("%s: could not find phandle\n",
					      np->full_name);
					goto err;
				}
			}

			if (cells_name) {
				if (of_read_u32(node, cells_name, &count)) {
					debug("%s: could not get %s for %s\n",
					      np->full_name, cells_name,
					      node->full_name);
					goto err;
				}
			} else {
				count = cell_count;
			}

			/*
			 * Make sure that the arguments actually fit in the
			 * remaining property data length
			 */
			if (list + count > list_end) {
				debug("%s: arguments longer than property\n",
				      np->full_name);
				goto err;
			}
		}

		/*
		 * All of the error cases above bail out of the loop, so at
		 * this point, the parsing is successful. If the requested
		 * index matches, then fill the out_args structure and return,
		 * or return -ENOENT for an empty entry.
		 */
		rc = -ENOENT;
		if (cur_index == index) {
			if (!phandle)
				goto err;

			if (out_args) {
				int i;
				if (WARN_ON(count > OF_MAX_PHANDLE_ARGS))
					count = OF_MAX_PHANDLE_ARGS;
				out_args->np = node;
				out_args->args_count = count;
				for (i = 0; i < count; i++)
					out_args->args[i] =
							be32_to_cpup(list++);
			} else {
				of_node_put(node);
			}

			/* Found it! return success */
			return 0;
		}

		of_node_put(node);
		node = NULL;
		list += count;
		cur_index++;
	}

	/*
	 * Unlock node before returning result; will be one of:
	 * -ENOENT : index is for empty phandle
	 * -EINVAL : parsing error on data
	 * [1..n]  : Number of phandle (count mode; when index = -1)
	 */
	rc = index < 0 ? cur_index : -ENOENT;
 err:
	if (node)
		of_node_put(node);
	return rc;
}

struct device_node *of_parse_phandle(const struct device_node *np,
				     const char *phandle_name, int index)
{
	struct of_phandle_args args;

	if (index < 0)
		return NULL;

	if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0, index,
					 &args))
		return NULL;

	return args.np;
}

int of_parse_phandle_with_args(const struct device_node *np,
			       const char *list_name, const char *cells_name,
			       int cell_count, int index,
			       struct of_phandle_args *out_args)
{
	if (index < 0)
		return -EINVAL;

	return __of_parse_phandle_with_args(np, list_name, cells_name,
					    cell_count, index, out_args);
}

int of_count_phandle_with_args(const struct device_node *np,
			       const char *list_name, const char *cells_name,
			       int cell_count)
{
	return __of_parse_phandle_with_args(np, list_name, cells_name,
					    cell_count, -1, NULL);
}

static void of_alias_add(struct alias_prop *ap, struct device_node *np,
			 int id, const char *stem, int stem_len)
{
	ap->np = np;
	ap->id = id;
	strncpy(ap->stem, stem, stem_len);
	ap->stem[stem_len] = 0;
	list_add_tail(&ap->link, &aliases_lookup);
	debug("adding DT alias:%s: stem=%s id=%i node=%s\n",
	      ap->alias, ap->stem, ap->id, of_node_full_name(np));
}

int of_alias_scan(void)
{
	struct property *pp;

	of_aliases = of_find_node_by_path("/aliases");
	of_chosen = of_find_node_by_path("/chosen");
	if (of_chosen == NULL)
		of_chosen = of_find_node_by_path("/chosen@0");

	if (of_chosen) {
		const char *name;

		name = of_get_property(of_chosen, "stdout-path", NULL);
		if (name)
			of_stdout = of_find_node_opts_by_path(NULL, name,
							&of_stdout_options);
	}

	if (!of_aliases)
		return 0;

	for_each_property_of_node(of_aliases, pp) {
		const char *start = pp->name;
		const char *end = start + strlen(start);
		struct device_node *np;
		struct alias_prop *ap;
		ulong id;
		int len;

		/* Skip those we do not want to proceed */
		if (!strcmp(pp->name, "name") ||
		    !strcmp(pp->name, "phandle") ||
		    !strcmp(pp->name, "linux,phandle"))
			continue;

		np = of_find_node_by_path(pp->value);
		if (!np)
			continue;

		/*
		 * walk the alias backwards to extract the id and work out
		 * the 'stem' string
		 */
		while (isdigit(*(end-1)) && end > start)
			end--;
		len = end - start;

		if (strict_strtoul(end, 10, &id) < 0)
			continue;

		/* Allocate an alias_prop with enough space for the stem */
		ap = malloc(sizeof(*ap) + len + 1);
		if (!ap)
			return -ENOMEM;
		memset(ap, 0, sizeof(*ap) + len + 1);
		ap->alias = start;
		of_alias_add(ap, np, id, start, len);
	}

	return 0;
}

int of_alias_get_id(const struct device_node *np, const char *stem)
{
	struct alias_prop *app;
	int id = -ENODEV;

	mutex_lock(&of_mutex);
	list_for_each_entry(app, &aliases_lookup, link) {
		if (strcmp(app->stem, stem) != 0)
			continue;

		if (np == app->np) {
			id = app->id;
			break;
		}
	}
	mutex_unlock(&of_mutex);

	return id;
}

int of_alias_get_highest_id(const char *stem)
{
	struct alias_prop *app;
	int id = -1;

	mutex_lock(&of_mutex);
	list_for_each_entry(app, &aliases_lookup, link) {
		if (strcmp(app->stem, stem) != 0)
			continue;

		if (app->id > id)
			id = app->id;
	}
	mutex_unlock(&of_mutex);

	return id;
}

struct device_node *of_get_stdout(void)
{
	return of_stdout;
}

int of_write_prop(struct device_node *np, const char *propname, int len,
		  const void *value)
{
	struct property *pp;
	struct property *pp_last = NULL;
	struct property *new;

	if (!np)
		return -EINVAL;

	for (pp = np->properties; pp; pp = pp->next) {
		if (strcmp(pp->name, propname) == 0) {
			/* Property exists -> change value */
			pp->value = (void *)value;
			pp->length = len;
			return 0;
		}
		pp_last = pp;
	}

	/* Property does not exist -> append new property */
	new = malloc(sizeof(struct property));
	if (!new)
		return -ENOMEM;

	new->name = strdup(propname);
	if (!new->name) {
		free(new);
		return -ENOMEM;
	}

	new->value = (void *)value;
	new->length = len;
	new->next = NULL;

	if (pp_last)
		pp_last->next = new;
	else
		np->properties = new;

	return 0;
}

int of_add_subnode(struct device_node *parent, const char *name, int len,
		   struct device_node **childp)
{
	struct device_node *child, *new, *last_sibling = NULL;
	char *new_name, *full_name;
	int parent_fnl;

	if (len == -1)
		len = strlen(name);
	__for_each_child_of_node(parent, child) {
		/*
		 * make sure we don't use a child called "trevor" when we are
		 * searching for "trev".
		 */
		if (!strncmp(child->name, name, len) && strlen(name) == len) {
			*childp = child;
			return -EEXIST;
		}
		last_sibling = child;
	}

	/* Subnode does not exist -> append new subnode */
	new = calloc(1, sizeof(struct device_node));
	if (!new)
		return -ENOMEM;

	new_name = memdup(name, len + 1);
	if (!new_name) {
		free(new);
		return -ENOMEM;
	}
	new_name[len] = '\0';

	/*
	 * if the parent is the root node (named "") we don't need to prepend
	 * its full path
	 */
	parent_fnl = *parent->name ? strlen(parent->full_name) : 0;
	full_name = calloc(1, parent_fnl + 1 + len + 1);
	if (!full_name) {
		free(new_name);
		free(new);
		return -ENOMEM;
	}
	new->name = new_name;	/* assign to constant pointer */

	strcpy(full_name, parent->full_name); /* "" for root node */
	full_name[parent_fnl] = '/';
	strlcpy(&full_name[parent_fnl + 1], name, len + 1);
	new->full_name = full_name;

	/* Add as last sibling of the parent */
	if (last_sibling)
		last_sibling->sibling = new;
	if (!parent->child)
		parent->child = new;
	new->parent = parent;

	*childp = new;

	return 0;
}