fdt.c 4.3 KB

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  1. /*
  2. * libfdt - Flat Device Tree manipulation
  3. * Copyright (C) 2006 David Gibson, IBM Corporation.
  4. * SPDX-License-Identifier: GPL-2.0+ BSD-2-Clause
  5. */
  6. #include <libfdt_env.h>
  7. #ifndef USE_HOSTCC
  8. #include <fdt.h>
  9. #include <libfdt.h>
  10. #else
  11. #include "fdt_host.h"
  12. #endif
  13. #include "libfdt_internal.h"
  14. int fdt_check_header(const void *fdt)
  15. {
  16. if (fdt_magic(fdt) == FDT_MAGIC) {
  17. /* Complete tree */
  18. if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
  19. return -FDT_ERR_BADVERSION;
  20. if (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION)
  21. return -FDT_ERR_BADVERSION;
  22. } else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
  23. /* Unfinished sequential-write blob */
  24. if (fdt_size_dt_struct(fdt) == 0)
  25. return -FDT_ERR_BADSTATE;
  26. } else {
  27. return -FDT_ERR_BADMAGIC;
  28. }
  29. return 0;
  30. }
  31. const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
  32. {
  33. unsigned absoffset = offset + fdt_off_dt_struct(fdt);
  34. if ((absoffset < offset)
  35. || ((absoffset + len) < absoffset)
  36. || (absoffset + len) > fdt_totalsize(fdt))
  37. return NULL;
  38. if (fdt_version(fdt) >= 0x11)
  39. if (((offset + len) < offset)
  40. || ((offset + len) > fdt_size_dt_struct(fdt)))
  41. return NULL;
  42. return _fdt_offset_ptr(fdt, offset);
  43. }
  44. uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
  45. {
  46. const fdt32_t *tagp, *lenp;
  47. uint32_t tag;
  48. int offset = startoffset;
  49. const char *p;
  50. *nextoffset = -FDT_ERR_TRUNCATED;
  51. tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
  52. if (!tagp)
  53. return FDT_END; /* premature end */
  54. tag = fdt32_to_cpu(*tagp);
  55. offset += FDT_TAGSIZE;
  56. *nextoffset = -FDT_ERR_BADSTRUCTURE;
  57. switch (tag) {
  58. case FDT_BEGIN_NODE:
  59. /* skip name */
  60. do {
  61. p = fdt_offset_ptr(fdt, offset++, 1);
  62. } while (p && (*p != '\0'));
  63. if (!p)
  64. return FDT_END; /* premature end */
  65. break;
  66. case FDT_PROP:
  67. lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
  68. if (!lenp)
  69. return FDT_END; /* premature end */
  70. /* skip-name offset, length and value */
  71. offset += sizeof(struct fdt_property) - FDT_TAGSIZE
  72. + fdt32_to_cpu(*lenp);
  73. break;
  74. case FDT_END:
  75. case FDT_END_NODE:
  76. case FDT_NOP:
  77. break;
  78. default:
  79. return FDT_END;
  80. }
  81. if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
  82. return FDT_END; /* premature end */
  83. *nextoffset = FDT_TAGALIGN(offset);
  84. return tag;
  85. }
  86. int _fdt_check_node_offset(const void *fdt, int offset)
  87. {
  88. if ((offset < 0) || (offset % FDT_TAGSIZE)
  89. || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
  90. return -FDT_ERR_BADOFFSET;
  91. return offset;
  92. }
  93. int _fdt_check_prop_offset(const void *fdt, int offset)
  94. {
  95. if ((offset < 0) || (offset % FDT_TAGSIZE)
  96. || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
  97. return -FDT_ERR_BADOFFSET;
  98. return offset;
  99. }
  100. int fdt_next_node(const void *fdt, int offset, int *depth)
  101. {
  102. int nextoffset = 0;
  103. uint32_t tag;
  104. if (offset >= 0)
  105. if ((nextoffset = _fdt_check_node_offset(fdt, offset)) < 0)
  106. return nextoffset;
  107. do {
  108. offset = nextoffset;
  109. tag = fdt_next_tag(fdt, offset, &nextoffset);
  110. switch (tag) {
  111. case FDT_PROP:
  112. case FDT_NOP:
  113. break;
  114. case FDT_BEGIN_NODE:
  115. if (depth)
  116. (*depth)++;
  117. break;
  118. case FDT_END_NODE:
  119. if (depth && ((--(*depth)) < 0))
  120. return nextoffset;
  121. break;
  122. case FDT_END:
  123. if ((nextoffset >= 0)
  124. || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
  125. return -FDT_ERR_NOTFOUND;
  126. else
  127. return nextoffset;
  128. }
  129. } while (tag != FDT_BEGIN_NODE);
  130. return offset;
  131. }
  132. int fdt_first_subnode(const void *fdt, int offset)
  133. {
  134. int depth = 0;
  135. offset = fdt_next_node(fdt, offset, &depth);
  136. if (offset < 0 || depth != 1)
  137. return -FDT_ERR_NOTFOUND;
  138. return offset;
  139. }
  140. int fdt_next_subnode(const void *fdt, int offset)
  141. {
  142. int depth = 1;
  143. /*
  144. * With respect to the parent, the depth of the next subnode will be
  145. * the same as the last.
  146. */
  147. do {
  148. offset = fdt_next_node(fdt, offset, &depth);
  149. if (offset < 0 || depth < 1)
  150. return -FDT_ERR_NOTFOUND;
  151. } while (depth > 1);
  152. return offset;
  153. }
  154. const char *_fdt_find_string(const char *strtab, int tabsize, const char *s)
  155. {
  156. int len = strlen(s) + 1;
  157. const char *last = strtab + tabsize - len;
  158. const char *p;
  159. for (p = strtab; p <= last; p++)
  160. if (memcmp(p, s, len) == 0)
  161. return p;
  162. return NULL;
  163. }
  164. int fdt_move(const void *fdt, void *buf, int bufsize)
  165. {
  166. FDT_CHECK_HEADER(fdt);
  167. if (fdt_totalsize(fdt) > bufsize)
  168. return -FDT_ERR_NOSPACE;
  169. memmove(buf, fdt, fdt_totalsize(fdt));
  170. return 0;
  171. }