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, unsigned int len)
78{
79	unsigned absoffset = offset + fdt_off_dt_struct(fdt);
80
81	if ((absoffset < offset)
82	    || ((absoffset + len) < absoffset)
83	    || (absoffset + len) > fdt_totalsize(fdt))
84		return NULL;
85
86	if (fdt_version(fdt) >= 0x11)
87		if (((offset + len) < offset)
88		    || ((offset + len) > fdt_size_dt_struct(fdt)))
89			return NULL;
90
91	return fdt_offset_ptr_(fdt, offset);
92}
93
94uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
95{
96	const fdt32_t *tagp, *lenp;
97	uint32_t tag;
98	int offset = startoffset;
99	const char *p;
100
101	*nextoffset = -FDT_ERR_TRUNCATED;
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	*nextoffset = -FDT_ERR_BADSTRUCTURE;
109	switch (tag) {
110	case FDT_BEGIN_NODE:
111		/* skip name */
112		do {
113			p = fdt_offset_ptr(fdt, offset++, 1);
114		} while (p && (*p != '\0'));
115		if (!p)
116			return FDT_END; /* premature end */
117		break;
118
119	case FDT_PROP:
120		lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
121		if (!lenp)
122			return FDT_END; /* premature end */
123		/* skip-name offset, length and value */
124		offset += sizeof(struct fdt_property) - FDT_TAGSIZE
125			+ fdt32_to_cpu(*lenp);
126		if (fdt_version(fdt) < 0x10 && fdt32_to_cpu(*lenp) >= 8 &&
127		    ((offset - fdt32_to_cpu(*lenp)) % 8) != 0)
128			offset += 4;
129		break;
130
131	case FDT_END:
132	case FDT_END_NODE:
133	case FDT_NOP:
134		break;
135
136	default:
137		return FDT_END;
138	}
139
140	if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
141		return FDT_END; /* premature end */
142
143	*nextoffset = FDT_TAGALIGN(offset);
144	return tag;
145}
146
147int fdt_check_node_offset_(const void *fdt, int offset)
148{
149	if ((offset < 0) || (offset % FDT_TAGSIZE)
150	    || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
151		return -FDT_ERR_BADOFFSET;
152
153	return offset;
154}
155
156int fdt_check_prop_offset_(const void *fdt, int offset)
157{
158	if ((offset < 0) || (offset % FDT_TAGSIZE)
159	    || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
160		return -FDT_ERR_BADOFFSET;
161
162	return offset;
163}
164
165int fdt_next_node(const void *fdt, int offset, int *depth)
166{
167	int nextoffset = 0;
168	uint32_t tag;
169
170	if (offset >= 0)
171		if ((nextoffset = fdt_check_node_offset_(fdt, offset)) < 0)
172			return nextoffset;
173
174	do {
175		offset = nextoffset;
176		tag = fdt_next_tag(fdt, offset, &nextoffset);
177
178		switch (tag) {
179		case FDT_PROP:
180		case FDT_NOP:
181			break;
182
183		case FDT_BEGIN_NODE:
184			if (depth)
185				(*depth)++;
186			break;
187
188		case FDT_END_NODE:
189			if (depth && ((--(*depth)) < 0))
190				return nextoffset;
191			break;
192
193		case FDT_END:
194			if ((nextoffset >= 0)
195			    || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
196				return -FDT_ERR_NOTFOUND;
197			else
198				return nextoffset;
199		}
200	} while (tag != FDT_BEGIN_NODE);
201
202	return offset;
203}
204
205int fdt_first_subnode(const void *fdt, int offset)
206{
207	int depth = 0;
208
209	offset = fdt_next_node(fdt, offset, &depth);
210	if (offset < 0 || depth != 1)
211		return -FDT_ERR_NOTFOUND;
212
213	return offset;
214}
215
216int fdt_next_subnode(const void *fdt, int offset)
217{
218	int depth = 1;
219
220	/*
221	 * With respect to the parent, the depth of the next subnode will be
222	 * the same as the last.
223	 */
224	do {
225		offset = fdt_next_node(fdt, offset, &depth);
226		if (offset < 0 || depth < 1)
227			return -FDT_ERR_NOTFOUND;
228	} while (depth > 1);
229
230	return offset;
231}
232
233const char *fdt_find_string_(const char *strtab, int tabsize, const char *s)
234{
235	int len = strlen(s) + 1;
236	const char *last = strtab + tabsize - len;
237	const char *p;
238
239	for (p = strtab; p <= last; p++)
240		if (memcmp(p, s, len) == 0)
241			return p;
242	return NULL;
243}
244
245int fdt_move(const void *fdt, void *buf, int bufsize)
246{
247	FDT_CHECK_HEADER(fdt);
248
249	if (fdt_totalsize(fdt) > bufsize)
250		return -FDT_ERR_NOSPACE;
251
252	memmove(buf, fdt, fdt_totalsize(fdt));
253	return 0;
254}
255