fdt.c 4.2 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. const char *p;
  34. if (fdt_version(fdt) >= 0x11)
  35. if (((offset + len) < offset)
  36. || ((offset + len) > fdt_size_dt_struct(fdt)))
  37. return NULL;
  38. p = _fdt_offset_ptr(fdt, offset);
  39. if (p + len < p)
  40. return NULL;
  41. return p;
  42. }
  43. uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
  44. {
  45. const fdt32_t *tagp, *lenp;
  46. uint32_t tag;
  47. int offset = startoffset;
  48. const char *p;
  49. *nextoffset = -FDT_ERR_TRUNCATED;
  50. tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
  51. if (!tagp)
  52. return FDT_END; /* premature end */
  53. tag = fdt32_to_cpu(*tagp);
  54. offset += FDT_TAGSIZE;
  55. *nextoffset = -FDT_ERR_BADSTRUCTURE;
  56. switch (tag) {
  57. case FDT_BEGIN_NODE:
  58. /* skip name */
  59. do {
  60. p = fdt_offset_ptr(fdt, offset++, 1);
  61. } while (p && (*p != '\0'));
  62. if (!p)
  63. return FDT_END; /* premature end */
  64. break;
  65. case FDT_PROP:
  66. lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
  67. if (!lenp)
  68. return FDT_END; /* premature end */
  69. /* skip-name offset, length and value */
  70. offset += sizeof(struct fdt_property) - FDT_TAGSIZE
  71. + fdt32_to_cpu(*lenp);
  72. break;
  73. case FDT_END:
  74. case FDT_END_NODE:
  75. case FDT_NOP:
  76. break;
  77. default:
  78. return FDT_END;
  79. }
  80. if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
  81. return FDT_END; /* premature end */
  82. *nextoffset = FDT_TAGALIGN(offset);
  83. return tag;
  84. }
  85. int _fdt_check_node_offset(const void *fdt, int offset)
  86. {
  87. if ((offset < 0) || (offset % FDT_TAGSIZE)
  88. || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
  89. return -FDT_ERR_BADOFFSET;
  90. return offset;
  91. }
  92. int _fdt_check_prop_offset(const void *fdt, int offset)
  93. {
  94. if ((offset < 0) || (offset % FDT_TAGSIZE)
  95. || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
  96. return -FDT_ERR_BADOFFSET;
  97. return offset;
  98. }
  99. int fdt_next_node(const void *fdt, int offset, int *depth)
  100. {
  101. int nextoffset = 0;
  102. uint32_t tag;
  103. if (offset >= 0)
  104. if ((nextoffset = _fdt_check_node_offset(fdt, offset)) < 0)
  105. return nextoffset;
  106. do {
  107. offset = nextoffset;
  108. tag = fdt_next_tag(fdt, offset, &nextoffset);
  109. switch (tag) {
  110. case FDT_PROP:
  111. case FDT_NOP:
  112. break;
  113. case FDT_BEGIN_NODE:
  114. if (depth)
  115. (*depth)++;
  116. break;
  117. case FDT_END_NODE:
  118. if (depth && ((--(*depth)) < 0))
  119. return nextoffset;
  120. break;
  121. case FDT_END:
  122. if ((nextoffset >= 0)
  123. || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
  124. return -FDT_ERR_NOTFOUND;
  125. else
  126. return nextoffset;
  127. }
  128. } while (tag != FDT_BEGIN_NODE);
  129. return offset;
  130. }
  131. int fdt_first_subnode(const void *fdt, int offset)
  132. {
  133. int depth = 0;
  134. offset = fdt_next_node(fdt, offset, &depth);
  135. if (offset < 0 || depth != 1)
  136. return -FDT_ERR_NOTFOUND;
  137. return offset;
  138. }
  139. int fdt_next_subnode(const void *fdt, int offset)
  140. {
  141. int depth = 1;
  142. /*
  143. * With respect to the parent, the depth of the next subnode will be
  144. * the same as the last.
  145. */
  146. do {
  147. offset = fdt_next_node(fdt, offset, &depth);
  148. if (offset < 0 || depth < 1)
  149. return -FDT_ERR_NOTFOUND;
  150. } while (depth > 1);
  151. return offset;
  152. }
  153. const char *_fdt_find_string(const char *strtab, int tabsize, const char *s)
  154. {
  155. int len = strlen(s) + 1;
  156. const char *last = strtab + tabsize - len;
  157. const char *p;
  158. for (p = strtab; p <= last; p++)
  159. if (memcmp(p, s, len) == 0)
  160. return p;
  161. return NULL;
  162. }
  163. int fdt_move(const void *fdt, void *buf, int bufsize)
  164. {
  165. FDT_CHECK_HEADER(fdt);
  166. if (fdt_totalsize(fdt) > bufsize)
  167. return -FDT_ERR_NOSPACE;
  168. memmove(buf, fdt, fdt_totalsize(fdt));
  169. return 0;
  170. }