summaryrefslogtreecommitdiff
path: root/libfdt/fdt_ro.c
blob: f8840839502b94ea3d17bd240c474fc662f0be9f (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
/*
 * libfdt - Flat Device Tree manipulation
 * Copyright (C) 2006 David Gibson, IBM Corporation.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include "libfdt_env.h"

#include <fdt.h>
#include <libfdt.h>

#include "libfdt_internal.h"

#define CHECK_HEADER(fdt) \
	{ \
		int err; \
		if ((err = _fdt_check_header(fdt)) != 0) \
			return err; \
	}

static int offset_streq(const void *fdt, int offset,
			const char *s, int len)
{
	const char *p = fdt_offset_ptr(fdt, offset, len+1);

	if (! p)
		/* short match */
		return 0;

	if (memcmp(p, s, len) != 0)
		return 0;

	if (p[len] != '\0')
		return 0;

	return 1;
}

/*
 * Return a pointer to the string at the given string offset.
 */
char *fdt_string(const void *fdt, int stroffset)
{
	return (char *)fdt + fdt_off_dt_strings(fdt) + stroffset;
}

/*
 * Return the node offset of the node specified by:
 *   parentoffset - starting place (0 to start at the root)
 *   name         - name being searched for
 *   namelen      - length of the name: typically strlen(name)
 *
 * Notes:
 *   If the start node has subnodes, the subnodes are _not_ searched for the
 *     requested name.
 */
int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
			       const char *name, int namelen)
{
	int level = 0;
	uint32_t tag;
	int offset, nextoffset;

	CHECK_HEADER(fdt);

	tag = fdt_next_tag(fdt, parentoffset, &nextoffset, NULL);
	if (tag != FDT_BEGIN_NODE)
		return -FDT_ERR_BADOFFSET;

	do {
		offset = nextoffset;
		tag = fdt_next_tag(fdt, offset, &nextoffset, NULL);

		switch (tag) {
		case FDT_END:
			return -FDT_ERR_TRUNCATED;

		case FDT_BEGIN_NODE:
			level++;
			/*
			 * If we are nested down levels, ignore the strings
			 * until we get back to the proper level.
			 */
			if (level != 1)
				continue;

			/* Return the offset if this is "our" string. */
			if (offset_streq(fdt, offset+FDT_TAGSIZE, name, namelen))
				return offset;
			break;

		case FDT_END_NODE:
			level--;
			break;

		case FDT_PROP:
		case FDT_NOP:
			break;

		default:
			return -FDT_ERR_BADSTRUCTURE;
		}
	} while (level >= 0);

	return -FDT_ERR_NOTFOUND;
}

/*
 * See fdt_subnode_offset_namelen()
 */
int fdt_subnode_offset(const void *fdt, int parentoffset,
		       const char *name)
{
	return fdt_subnode_offset_namelen(fdt, parentoffset, name, strlen(name));
}

/*
 * Searches for the node corresponding to the given path and returns the
 * offset of that node.
 */
int fdt_path_offset(const void *fdt, const char *path)
{
	const char *end = path + strlen(path);
	const char *p = path;
	int offset = 0;

	CHECK_HEADER(fdt);

	/* Paths must be absolute */
	if (*path != '/')
		return -FDT_ERR_BADPATH;

	while (*p) {
		const char *q;

		/* Skip path separator(s) */
		while (*p == '/')
			p++;
		if (! *p)
			return -FDT_ERR_BADPATH;

		/*
		 * Find the next path separator.  The characters between
		 * p and q are the next segment of the the path to find.
		 */
		q = strchr(p, '/');
		if (! q)
			q = end;

		/*
		 * Find the offset corresponding to the this path segment.
		 */
		offset = fdt_subnode_offset_namelen(fdt, offset, p, q-p);

		/* Oops, error, abort abort abort */
		if (offset < 0)
			return offset;

		p = q;
	}

	return offset;	
}

/*
 * Given the offset of a node and a name of a property in that node, return
 * a pointer to the property struct.
 */
struct fdt_property *fdt_get_property(const void *fdt,
				      int nodeoffset,
				      const char *name, int *lenp)
{
	int level = 0;
	uint32_t tag;
	struct fdt_property *prop;
	int namestroff;
	int offset, nextoffset;
	int err;

	if ((err = _fdt_check_header(fdt)) != 0)
		goto fail;

	err = -FDT_ERR_BADOFFSET;
	if (nodeoffset % FDT_TAGSIZE)
		goto fail;

	tag = fdt_next_tag(fdt, nodeoffset, &nextoffset, NULL);
	if (tag != FDT_BEGIN_NODE)
		goto fail;

	do {
		offset = nextoffset;

		tag = fdt_next_tag(fdt, offset, &nextoffset, NULL);
		switch (tag) {
		case FDT_END:
			err = -FDT_ERR_TRUNCATED;
			goto fail;

		case FDT_BEGIN_NODE:
			level++;
			break;

		case FDT_END_NODE:
			level--;
			break;

		case FDT_PROP:
			/*
			 * If we are nested down levels, ignore the strings
			 * until we get back to the proper level.
			 */
			if (level != 0)
				continue;

			err = -FDT_ERR_BADSTRUCTURE;
			prop = fdt_offset_ptr_typed(fdt, offset, prop);
			if (! prop)
				goto fail;
			namestroff = fdt32_to_cpu(prop->nameoff);
			if (streq(fdt_string(fdt, namestroff), name)) {
				/* Found it! */
				int len = fdt32_to_cpu(prop->len);
				prop = fdt_offset_ptr(fdt, offset,
						      sizeof(*prop)+len);
				if (! prop)
					goto fail;

				if (lenp)
					*lenp = len;
				
				return prop;
			}
			break;

		case FDT_NOP:
			break;

		default:
			err = -FDT_ERR_BADSTRUCTURE;
			goto fail;
		}
	} while (level >= 0);

	err = -FDT_ERR_NOTFOUND;
 fail:
	if (lenp)
		*lenp = err;
	return NULL;
}

/*
 * Given the offset of a node and a name of a property in that node, return
 * a pointer to the property data (ONLY).
 */
void *fdt_getprop(const void *fdt, int nodeoffset,
		  const char *name, int *lenp)
{
	const struct fdt_property *prop;

	prop = fdt_get_property(fdt, nodeoffset, name, lenp);
	if (! prop)
		return NULL;

	return (void *)prop->data;
}


uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset, char **namep)
{
	const uint32_t *tagp, *lenp;
	uint32_t tag;
	const char *p;

	if (offset % FDT_TAGSIZE)
		return -1;

	tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
	if (! tagp)
		return FDT_END; /* premature end */
	tag = fdt32_to_cpu(*tagp);
	offset += FDT_TAGSIZE;

	switch (tag) {
	case FDT_BEGIN_NODE:
		if(namep)
			*namep = fdt_offset_ptr(fdt, offset, 1);

		/* skip name */
		do {
			p = fdt_offset_ptr(fdt, offset++, 1);
		} while (p && (*p != '\0'));
		if (! p)
			return FDT_END;
		break;
	case FDT_PROP:
		lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
		if (! lenp)
			return FDT_END;
		/*
		 * Get the property and set the namep to the name.
		 */
		if(namep) {
			struct fdt_property *prop;

			prop = fdt_offset_ptr_typed(fdt, offset - FDT_TAGSIZE, prop);
			if (! prop)
				return -FDT_ERR_BADSTRUCTURE;
			*namep = fdt_string(fdt, fdt32_to_cpu(prop->nameoff));
		}
		/* skip name offset, length and value */
		offset += 2*FDT_TAGSIZE + fdt32_to_cpu(*lenp);
		break;
	}

	if (nextoffset)
		*nextoffset = ALIGN(offset, FDT_TAGSIZE);

	return tag;
}