fdt.c revision 204431 
1/*
2 * libfdt - Flat Device Tree manipulation
3 * Copyright (C) 2006 David Gibson, IBM Corporation.
4 *
5 * libfdt is dual licensed: you can use it either under the terms of
6 * the GPL, or the BSD license, at your option.
7 *
8 *  a) This library is free software; you can redistribute it and/or
9 *     modify it under the terms of the GNU General Public License as
10 *     published by the Free Software Foundation; either version 2 of the
11 *     License, or (at your option) any later version.
12 *
13 *     This library is distributed in the hope that it will be useful,
14 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
15 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 *     GNU General Public License for more details.
17 *
18 *     You should have received a copy of the GNU General Public
19 *     License along with this library; if not, write to the Free
20 *     Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
21 *     MA 02110-1301 USA
22 *
23 * Alternatively,
24 *
25 *  b) Redistribution and use in source and binary forms, with or
26 *     without modification, are permitted provided that the following
27 *     conditions are met:
28 *
29 *     1. Redistributions of source code must retain the above
30 *        copyright notice, this list of conditions and the following
31 *        disclaimer.
32 *     2. Redistributions in binary form must reproduce the above
33 *        copyright notice, this list of conditions and the following
34 *        disclaimer in the documentation and/or other materials
35 *        provided with the distribution.
36 *
37 *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
38 *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
39 *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
40 *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
41 *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
42 *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
43 *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
44 *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
45 *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
46 *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
47 *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
48 *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
49 *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
50 */
51#include "libfdt_env.h"
52
53#include <fdt.h>
54#include <libfdt.h>
55
56#include "libfdt_internal.h"
57
58int fdt_check_header(const void *fdt)
59{
60	if (fdt_magic(fdt) == FDT_MAGIC) {
61		/* Complete tree */
62		if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
63			return -FDT_ERR_BADVERSION;
64		if (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION)
65			return -FDT_ERR_BADVERSION;
66	} else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
67		/* Unfinished sequential-write blob */
68		if (fdt_size_dt_struct(fdt) == 0)
69			return -FDT_ERR_BADSTATE;
70	} else {
71		return -FDT_ERR_BADMAGIC;
72	}
73
74	return 0;
75}
76
77const void *fdt_offset_ptr(const void *fdt, int offset, int len)
78{
79	const char *p;
80
81	if (fdt_version(fdt) >= 0x11)
82		if (((offset + len) < offset)
83		    || ((offset + len) > fdt_size_dt_struct(fdt)))
84			return NULL;
85
86	p = _fdt_offset_ptr(fdt, offset);
87
88	if (p + len < p)
89		return NULL;
90	return p;
91}
92
93uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset)
94{
95	const uint32_t *tagp, *lenp;
96	uint32_t tag;
97	const char *p;
98
99	if (offset % FDT_TAGSIZE)
100		return -1;
101
102	tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
103	if (! tagp)
104		return FDT_END; /* premature end */
105	tag = fdt32_to_cpu(*tagp);
106	offset += FDT_TAGSIZE;
107
108	switch (tag) {
109	case FDT_BEGIN_NODE:
110		/* skip name */
111		do {
112			p = fdt_offset_ptr(fdt, offset++, 1);
113		} while (p && (*p != '\0'));
114		if (! p)
115			return FDT_END;
116		break;
117	case FDT_PROP:
118		lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
119		if (! lenp)
120			return FDT_END;
121		/* skip name offset, length and value */
122		offset += 2*FDT_TAGSIZE + fdt32_to_cpu(*lenp);
123		break;
124	}
125
126	if (nextoffset)
127		*nextoffset = FDT_TAGALIGN(offset);
128
129	return tag;
130}
131
132int _fdt_check_node_offset(const void *fdt, int offset)
133{
134	if ((offset < 0) || (offset % FDT_TAGSIZE)
135	    || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
136		return -FDT_ERR_BADOFFSET;
137
138	return offset;
139}
140
141int fdt_next_node(const void *fdt, int offset, int *depth)
142{
143	int nextoffset = 0;
144	uint32_t tag;
145
146	if (offset >= 0)
147		if ((nextoffset = _fdt_check_node_offset(fdt, offset)) < 0)
148			return nextoffset;
149
150	do {
151		offset = nextoffset;
152		tag = fdt_next_tag(fdt, offset, &nextoffset);
153
154		switch (tag) {
155		case FDT_PROP:
156		case FDT_NOP:
157			break;
158
159		case FDT_BEGIN_NODE:
160			if (depth)
161				(*depth)++;
162			break;
163
164		case FDT_END_NODE:
165			if (depth)
166				(*depth)--;
167			break;
168
169		case FDT_END:
170			return -FDT_ERR_NOTFOUND;
171
172		default:
173			return -FDT_ERR_BADSTRUCTURE;
174		}
175	} while (tag != FDT_BEGIN_NODE);
176
177	return offset;
178}
179
180const char *_fdt_find_string(const char *strtab, int tabsize, const char *s)
181{
182	int len = strlen(s) + 1;
183	const char *last = strtab + tabsize - len;
184	const char *p;
185
186	for (p = strtab; p <= last; p++)
187		if (memcmp(p, s, len) == 0)
188			return p;
189	return NULL;
190}
191
192int fdt_move(const void *fdt, void *buf, int bufsize)
193{
194	FDT_CHECK_HEADER(fdt);
195
196	if (fdt_totalsize(fdt) > bufsize)
197		return -FDT_ERR_NOSPACE;
198
199	memmove(buf, fdt, fdt_totalsize(fdt));
200	return 0;
201}
202