fdt.c 7.7 KB

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  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. #include <fdt.h>
  53. #include <libfdt.h>
  54. #include "libfdt_internal.h"
  55. int
  56. fdt_check_header (
  57. const void *fdt
  58. )
  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. }
  65. if (fdt_last_comp_version (fdt) > FDT_LAST_SUPPORTED_VERSION) {
  66. return -FDT_ERR_BADVERSION;
  67. }
  68. } else if (fdt_magic (fdt) == FDT_SW_MAGIC) {
  69. /* Unfinished sequential-write blob */
  70. if (fdt_size_dt_struct (fdt) == 0) {
  71. return -FDT_ERR_BADSTATE;
  72. }
  73. } else {
  74. return -FDT_ERR_BADMAGIC;
  75. }
  76. return 0;
  77. }
  78. const void *
  79. fdt_offset_ptr (
  80. const void *fdt,
  81. int offset,
  82. unsigned int len
  83. )
  84. {
  85. unsigned absoffset = offset + fdt_off_dt_struct (fdt);
  86. if ( (absoffset < offset)
  87. || ((absoffset + len) < absoffset)
  88. || ((absoffset + len) > fdt_totalsize (fdt)))
  89. {
  90. return NULL;
  91. }
  92. if (fdt_version (fdt) >= 0x11) {
  93. if ( ((offset + len) < offset)
  94. || ((offset + len) > fdt_size_dt_struct (fdt)))
  95. {
  96. return NULL;
  97. }
  98. }
  99. return _fdt_offset_ptr (fdt, offset);
  100. }
  101. uint32_t
  102. fdt_next_tag (
  103. const void *fdt,
  104. int startoffset,
  105. int *nextoffset
  106. )
  107. {
  108. const fdt32_t *tagp, *lenp;
  109. uint32_t tag;
  110. int offset = startoffset;
  111. const char *p;
  112. *nextoffset = -FDT_ERR_TRUNCATED;
  113. tagp = fdt_offset_ptr (fdt, offset, FDT_TAGSIZE);
  114. if (!tagp) {
  115. return FDT_END; /* premature end */
  116. }
  117. tag = fdt32_to_cpu (*tagp);
  118. offset += FDT_TAGSIZE;
  119. *nextoffset = -FDT_ERR_BADSTRUCTURE;
  120. switch (tag) {
  121. case FDT_BEGIN_NODE:
  122. /* skip name */
  123. do {
  124. p = fdt_offset_ptr (fdt, offset++, 1);
  125. } while (p && (*p != '\0'));
  126. if (!p) {
  127. return FDT_END; /* premature end */
  128. }
  129. break;
  130. case FDT_PROP:
  131. lenp = fdt_offset_ptr (fdt, offset, sizeof (*lenp));
  132. if (!lenp) {
  133. return FDT_END; /* premature end */
  134. }
  135. /* skip-name offset, length and value */
  136. offset += sizeof (struct fdt_property) - FDT_TAGSIZE
  137. + fdt32_to_cpu (*lenp);
  138. break;
  139. case FDT_END:
  140. case FDT_END_NODE:
  141. case FDT_NOP:
  142. break;
  143. default:
  144. return FDT_END;
  145. }
  146. if (!fdt_offset_ptr (fdt, startoffset, offset - startoffset)) {
  147. return FDT_END; /* premature end */
  148. }
  149. *nextoffset = FDT_TAGALIGN (offset);
  150. return tag;
  151. }
  152. int
  153. _fdt_check_node_offset (
  154. const void *fdt,
  155. int offset
  156. )
  157. {
  158. if ( (offset < 0) || (offset % FDT_TAGSIZE)
  159. || (fdt_next_tag (fdt, offset, &offset) != FDT_BEGIN_NODE))
  160. {
  161. return -FDT_ERR_BADOFFSET;
  162. }
  163. return offset;
  164. }
  165. int
  166. _fdt_check_prop_offset (
  167. const void *fdt,
  168. int offset
  169. )
  170. {
  171. if ( (offset < 0) || (offset % FDT_TAGSIZE)
  172. || (fdt_next_tag (fdt, offset, &offset) != FDT_PROP))
  173. {
  174. return -FDT_ERR_BADOFFSET;
  175. }
  176. return offset;
  177. }
  178. int
  179. fdt_next_node (
  180. const void *fdt,
  181. int offset,
  182. int *depth
  183. )
  184. {
  185. int nextoffset = 0;
  186. uint32_t tag;
  187. if (offset >= 0) {
  188. if ((nextoffset = _fdt_check_node_offset (fdt, offset)) < 0) {
  189. return nextoffset;
  190. }
  191. }
  192. do {
  193. offset = nextoffset;
  194. tag = fdt_next_tag (fdt, offset, &nextoffset);
  195. switch (tag) {
  196. case FDT_PROP:
  197. case FDT_NOP:
  198. break;
  199. case FDT_BEGIN_NODE:
  200. if (depth) {
  201. (*depth)++;
  202. }
  203. break;
  204. case FDT_END_NODE:
  205. if (depth && ((--(*depth)) < 0)) {
  206. return nextoffset;
  207. }
  208. break;
  209. case FDT_END:
  210. if ( (nextoffset >= 0)
  211. || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
  212. {
  213. return -FDT_ERR_NOTFOUND;
  214. } else {
  215. return nextoffset;
  216. }
  217. }
  218. } while (tag != FDT_BEGIN_NODE);
  219. return offset;
  220. }
  221. int
  222. fdt_first_subnode (
  223. const void *fdt,
  224. int offset
  225. )
  226. {
  227. int depth = 0;
  228. offset = fdt_next_node (fdt, offset, &depth);
  229. if ((offset < 0) || (depth != 1)) {
  230. return -FDT_ERR_NOTFOUND;
  231. }
  232. return offset;
  233. }
  234. int
  235. fdt_next_subnode (
  236. const void *fdt,
  237. int offset
  238. )
  239. {
  240. int depth = 1;
  241. /*
  242. * With respect to the parent, the depth of the next subnode will be
  243. * the same as the last.
  244. */
  245. do {
  246. offset = fdt_next_node (fdt, offset, &depth);
  247. if ((offset < 0) || (depth < 1)) {
  248. return -FDT_ERR_NOTFOUND;
  249. }
  250. } while (depth > 1);
  251. return offset;
  252. }
  253. const char *
  254. _fdt_find_string (
  255. const char *strtab,
  256. int tabsize,
  257. const char *s
  258. )
  259. {
  260. int len = strlen (s) + 1;
  261. const char *last = strtab + tabsize - len;
  262. const char *p;
  263. for (p = strtab; p <= last; p++) {
  264. if (memcmp (p, s, len) == 0) {
  265. return p;
  266. }
  267. }
  268. return NULL;
  269. }
  270. int
  271. fdt_move (
  272. const void *fdt,
  273. void *buf,
  274. int bufsize
  275. )
  276. {
  277. FDT_CHECK_HEADER (fdt);
  278. if (fdt_totalsize (fdt) > bufsize) {
  279. return -FDT_ERR_NOSPACE;
  280. }
  281. memmove (buf, fdt, fdt_totalsize (fdt));
  282. return 0;
  283. }