1 // SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
2 /*
3 * libfdt - Flat Device Tree manipulation
4 * Copyright (C) 2006 David Gibson, IBM Corporation.
5 */
6 #include "libfdt_env.h"
7
8 #include <fdt.h>
9 #include <libfdt.h>
10
11 #include "libfdt_internal.h"
12
13 static int fdt_nodename_eq_(const void *fdt, int offset,
14 const char *s, int len)
15 {
16 int olen;
17 const char *p = fdt_get_name(fdt, offset, &olen);
18
19 if (!p || olen < len)
20 /* short match */
21 return 0;
22
23 if (memcmp(p, s, len) != 0)
24 return 0;
25
26 if (p[len] == '\0')
27 return 1;
28 else if (!memchr(s, '@', len) && (p[len] == '@'))
29 return 1;
30 else
31 return 0;
32 }
33
34 const char *fdt_get_string(const void *fdt, int stroffset, int *lenp)
35 {
36 int32_t totalsize;
37 uint32_t absoffset;
38 size_t len;
39 int err;
40 const char *s, *n;
41
42 if (can_assume(VALID_INPUT)) {
43 s = (const char *)fdt + fdt_off_dt_strings(fdt) + stroffset;
44
45 if (lenp)
46 *lenp = strlen(s);
47 return s;
48 }
49 totalsize = fdt_ro_probe_(fdt);
50 err = totalsize;
51 if (totalsize < 0)
52 goto fail;
53
54 err = -FDT_ERR_BADOFFSET;
55 absoffset = stroffset + fdt_off_dt_strings(fdt);
56 if (absoffset >= (unsigned)totalsize)
57 goto fail;
58 len = totalsize - absoffset;
59
60 if (fdt_magic(fdt) == FDT_MAGIC) {
61 if (stroffset < 0)
62 goto fail;
63 if (can_assume(LATEST) || fdt_version(fdt) >= 17) {
64 if ((unsigned)stroffset >= fdt_size_dt_strings(fdt))
65 goto fail;
66 if ((fdt_size_dt_strings(fdt) - stroffset) < len)
67 len = fdt_size_dt_strings(fdt) - stroffset;
68 }
69 } else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
70 unsigned int sw_stroffset = -stroffset;
71
72 if ((stroffset >= 0) ||
73 (sw_stroffset > fdt_size_dt_strings(fdt)))
74 goto fail;
75 if (sw_stroffset < len)
76 len = sw_stroffset;
77 } else {
78 err = -FDT_ERR_INTERNAL;
79 goto fail;
80 }
81
82 s = (const char *)fdt + absoffset;
83 n = memchr(s, '\0', len);
84 if (!n) {
85 /* missing terminating NULL */
86 err = -FDT_ERR_TRUNCATED;
87 goto fail;
88 }
89
90 if (lenp)
91 *lenp = n - s;
92 return s;
93
94 fail:
95 if (lenp)
96 *lenp = err;
97 return NULL;
98 }
99
100 const char *fdt_string(const void *fdt, int stroffset)
101 {
102 return fdt_get_string(fdt, stroffset, NULL);
103 }
104
105 static int fdt_string_eq_(const void *fdt, int stroffset,
106 const char *s, int len)
107 {
108 int slen;
109 const char *p = fdt_get_string(fdt, stroffset, &slen);
110
111 return p && (slen == len) && (memcmp(p, s, len) == 0);
112 }
113
114 int fdt_find_max_phandle(const void *fdt, uint32_t *phandle)
115 {
116 uint32_t max = 0;
117 int offset = -1;
118
119 while (true) {
120 uint32_t value;
121
122 offset = fdt_next_node(fdt, offset, NULL);
123 if (offset < 0) {
124 if (offset == -FDT_ERR_NOTFOUND)
125 break;
126
127 return offset;
128 }
129
130 value = fdt_get_phandle(fdt, offset);
131
132 if (value > max)
133 max = value;
134 }
135
136 if (phandle)
137 *phandle = max;
138
139 return 0;
140 }
141
142 int fdt_generate_phandle(const void *fdt, uint32_t *phandle)
143 {
144 uint32_t max;
145 int err;
146
147 err = fdt_find_max_phandle(fdt, &max);
148 if (err < 0)
149 return err;
150
151 if (max == FDT_MAX_PHANDLE)
152 return -FDT_ERR_NOPHANDLES;
153
154 if (phandle)
155 *phandle = max + 1;
156
157 return 0;
158 }
159
160 static const struct fdt_reserve_entry *fdt_mem_rsv(const void *fdt, int n)
161 {
162 unsigned int offset = n * sizeof(struct fdt_reserve_entry);
163 unsigned int absoffset = fdt_off_mem_rsvmap(fdt) + offset;
164
165 if (!can_assume(VALID_INPUT)) {
166 if (absoffset < fdt_off_mem_rsvmap(fdt))
167 return NULL;
168 if (absoffset > fdt_totalsize(fdt) -
169 sizeof(struct fdt_reserve_entry))
170 return NULL;
171 }
172 return fdt_mem_rsv_(fdt, n);
173 }
174
175 int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size)
176 {
177 const struct fdt_reserve_entry *re;
178
179 FDT_RO_PROBE(fdt);
180 re = fdt_mem_rsv(fdt, n);
181 if (!can_assume(VALID_INPUT) && !re)
182 return -FDT_ERR_BADOFFSET;
183
184 *address = fdt64_ld_(&re->address);
185 *size = fdt64_ld_(&re->size);
186 return 0;
187 }
188
189 int fdt_num_mem_rsv(const void *fdt)
190 {
191 int i;
192 const struct fdt_reserve_entry *re;
193
194 for (i = 0; (re = fdt_mem_rsv(fdt, i)) != NULL; i++) {
195 if (fdt64_ld_(&re->size) == 0)
196 return i;
197 }
198 return -FDT_ERR_TRUNCATED;
199 }
200
201 static int nextprop_(const void *fdt, int offset)
202 {
203 uint32_t tag;
204 int nextoffset;
205
206 do {
207 tag = fdt_next_tag(fdt, offset, &nextoffset);
208
209 switch (tag) {
210 case FDT_END:
211 if (nextoffset >= 0)
212 return -FDT_ERR_BADSTRUCTURE;
213 else
214 return nextoffset;
215
216 case FDT_PROP:
217 return offset;
218 }
219 offset = nextoffset;
220 } while (tag == FDT_NOP);
221
222 return -FDT_ERR_NOTFOUND;
223 }
224
225 int fdt_subnode_offset_namelen(const void *fdt, int offset,
226 const char *name, int namelen)
227 {
228 int depth;
229
230 FDT_RO_PROBE(fdt);
231
232 for (depth = 0;
233 (offset >= 0) && (depth >= 0);
234 offset = fdt_next_node(fdt, offset, &depth))
235 if ((depth == 1)
236 && fdt_nodename_eq_(fdt, offset, name, namelen))
237 return offset;
238
239 if (depth < 0)
240 return -FDT_ERR_NOTFOUND;
241 return offset; /* error */
242 }
243
244 int fdt_subnode_offset(const void *fdt, int parentoffset,
245 const char *name)
246 {
247 return fdt_subnode_offset_namelen(fdt, parentoffset, name, strlen(name));
248 }
249
250 int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen)
251 {
252 const char *end = path + namelen;
253 const char *p = path;
254 int offset = 0;
255
256 FDT_RO_PROBE(fdt);
257
258 if (!can_assume(VALID_INPUT) && namelen <= 0)
259 return -FDT_ERR_BADPATH;
260
261 /* see if we have an alias */
262 if (*path != '/') {
263 const char *q = memchr(path, '/', end - p);
264
265 if (!q)
266 q = end;
267
268 p = fdt_get_alias_namelen(fdt, p, q - p);
269 if (!p)
270 return -FDT_ERR_BADPATH;
271 offset = fdt_path_offset(fdt, p);
272
273 p = q;
274 }
275
276 while (p < end) {
277 const char *q;
278
279 while (*p == '/') {
280 p++;
281 if (p == end)
282 return offset;
283 }
284 q = memchr(p, '/', end - p);
285 if (! q)
286 q = end;
287
288 offset = fdt_subnode_offset_namelen(fdt, offset, p, q-p);
289 if (offset < 0)
290 return offset;
291
292 p = q;
293 }
294
295 return offset;
296 }
297
298 int fdt_path_offset(const void *fdt, const char *path)
299 {
300 return fdt_path_offset_namelen(fdt, path, strlen(path));
301 }
302
303 const char *fdt_get_name(const void *fdt, int nodeoffset, int *len)
304 {
305 const struct fdt_node_header *nh = fdt_offset_ptr_(fdt, nodeoffset);
306 const char *nameptr;
307 int err;
308
309 if (((err = fdt_ro_probe_(fdt)) < 0)
310 || ((err = fdt_check_node_offset_(fdt, nodeoffset)) < 0))
311 goto fail;
312
313 nameptr = nh->name;
314
315 if (!can_assume(LATEST) && fdt_version(fdt) < 0x10) {
316 /*
317 * For old FDT versions, match the naming conventions of V16:
318 * give only the leaf name (after all /). The actual tree
319 * contents are loosely checked.
320 */
321 const char *leaf;
322 leaf = strrchr(nameptr, '/');
323 if (leaf == NULL) {
324 err = -FDT_ERR_BADSTRUCTURE;
325 goto fail;
326 }
327 nameptr = leaf+1;
328 }
329
330 if (len)
331 *len = strlen(nameptr);
332
333 return nameptr;
334
335 fail:
336 if (len)
337 *len = err;
338 return NULL;
339 }
340
341 int fdt_first_property_offset(const void *fdt, int nodeoffset)
342 {
343 int offset;
344
345 if ((offset = fdt_check_node_offset_(fdt, nodeoffset)) < 0)
346 return offset;
347
348 return nextprop_(fdt, offset);
349 }
350
351 int fdt_next_property_offset(const void *fdt, int offset)
352 {
353 if ((offset = fdt_check_prop_offset_(fdt, offset)) < 0)
354 return offset;
355
356 return nextprop_(fdt, offset);
357 }
358
359 static const struct fdt_property *fdt_get_property_by_offset_(const void *fdt,
360 int offset,
361 int *lenp)
362 {
363 int err;
364 const struct fdt_property *prop;
365
366 if (!can_assume(VALID_INPUT) &&
367 (err = fdt_check_prop_offset_(fdt, offset)) < 0) {
368 if (lenp)
369 *lenp = err;
370 return NULL;
371 }
372
373 prop = fdt_offset_ptr_(fdt, offset);
374
375 if (lenp)
376 *lenp = fdt32_ld_(&prop->len);
377
378 return prop;
379 }
380
381 const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
382 int offset,
383 int *lenp)
384 {
385 /* Prior to version 16, properties may need realignment
386 * and this API does not work. fdt_getprop_*() will, however. */
387
388 if (!can_assume(LATEST) && fdt_version(fdt) < 0x10) {
389 if (lenp)
390 *lenp = -FDT_ERR_BADVERSION;
391 return NULL;
392 }
393
394 return fdt_get_property_by_offset_(fdt, offset, lenp);
395 }
396
397 static const struct fdt_property *fdt_get_property_namelen_(const void *fdt,
398 int offset,
399 const char *name,
400 int namelen,
401 int *lenp,
402 int *poffset)
403 {
404 for (offset = fdt_first_property_offset(fdt, offset);
405 (offset >= 0);
406 (offset = fdt_next_property_offset(fdt, offset))) {
407 const struct fdt_property *prop;
408
409 prop = fdt_get_property_by_offset_(fdt, offset, lenp);
410 if (!can_assume(LIBFDT_FLAWLESS) && !prop) {
411 offset = -FDT_ERR_INTERNAL;
412 break;
413 }
414 if (fdt_string_eq_(fdt, fdt32_ld_(&prop->nameoff),
415 name, namelen)) {
416 if (poffset)
417 *poffset = offset;
418 return prop;
419 }
420 }
421
422 if (lenp)
423 *lenp = offset;
424 return NULL;
425 }
426
427
428 const struct fdt_property *fdt_get_property_namelen(const void *fdt,
429 int offset,
430 const char *name,
431 int namelen, int *lenp)
432 {
433 /* Prior to version 16, properties may need realignment
434 * and this API does not work. fdt_getprop_*() will, however. */
435 if (!can_assume(LATEST) && fdt_version(fdt) < 0x10) {
436 if (lenp)
437 *lenp = -FDT_ERR_BADVERSION;
438 return NULL;
439 }
440
441 return fdt_get_property_namelen_(fdt, offset, name, namelen, lenp,
442 NULL);
443 }
444
445
446 const struct fdt_property *fdt_get_property(const void *fdt,
447 int nodeoffset,
448 const char *name, int *lenp)
449 {
450 return fdt_get_property_namelen(fdt, nodeoffset, name,
451 strlen(name), lenp);
452 }
453
454 const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
455 const char *name, int namelen, int *lenp)
456 {
457 int poffset;
458 const struct fdt_property *prop;
459
460 prop = fdt_get_property_namelen_(fdt, nodeoffset, name, namelen, lenp,
461 &poffset);
462 if (!prop)
463 return NULL;
464
465 /* Handle realignment */
466 if (!can_assume(LATEST) && fdt_version(fdt) < 0x10 &&
467 (poffset + sizeof(*prop)) % 8 && fdt32_ld_(&prop->len) >= 8)
468 return prop->data + 4;
469 return prop->data;
470 }
471
472 const void *fdt_getprop_by_offset(const void *fdt, int offset,
473 const char **namep, int *lenp)
474 {
475 const struct fdt_property *prop;
476
477 prop = fdt_get_property_by_offset_(fdt, offset, lenp);
478 if (!prop)
479 return NULL;
480 if (namep) {
481 const char *name;
482 int namelen;
483
484 if (!can_assume(VALID_INPUT)) {
485 name = fdt_get_string(fdt, fdt32_ld_(&prop->nameoff),
486 &namelen);
487 *namep = name;
488 if (!name) {
489 if (lenp)
490 *lenp = namelen;
491 return NULL;
492 }
493 } else {
494 *namep = fdt_string(fdt, fdt32_ld_(&prop->nameoff));
495 }
496 }
497
498 /* Handle realignment */
499 if (!can_assume(LATEST) && fdt_version(fdt) < 0x10 &&
500 (offset + sizeof(*prop)) % 8 && fdt32_ld_(&prop->len) >= 8)
501 return prop->data + 4;
502 return prop->data;
503 }
504
505 const void *fdt_getprop(const void *fdt, int nodeoffset,
506 const char *name, int *lenp)
507 {
508 return fdt_getprop_namelen(fdt, nodeoffset, name, strlen(name), lenp);
509 }
510
511 uint32_t fdt_get_phandle(const void *fdt, int nodeoffset)
512 {
513 const fdt32_t *php;
514 int len;
515
516 /* FIXME: This is a bit sub-optimal, since we potentially scan
517 * over all the properties twice. */
518 php = fdt_getprop(fdt, nodeoffset, "phandle", &len);
519 if (!php || (len != sizeof(*php))) {
520 php = fdt_getprop(fdt, nodeoffset, "linux,phandle", &len);
521 if (!php || (len != sizeof(*php)))
522 return 0;
523 }
524
525 return fdt32_ld_(php);
526 }
527
528 static const void *fdt_path_getprop_namelen(const void *fdt, const char *path,
529 const char *propname, int propnamelen,
530 int *lenp)
531 {
532 int offset = fdt_path_offset(fdt, path);
533
534 if (offset < 0)
535 return NULL;
536
537 return fdt_getprop_namelen(fdt, offset, propname, propnamelen, lenp);
538 }
539
540 const char *fdt_get_alias_namelen(const void *fdt,
541 const char *name, int namelen)
542 {
543 int len;
544 const char *alias;
545
546 alias = fdt_path_getprop_namelen(fdt, "/aliases", name, namelen, &len);
547
548 if (!can_assume(VALID_DTB) &&
549 !(alias && len > 0 && alias[len - 1] == '\0' && *alias == '/'))
550 return NULL;
551
552 return alias;
553 }
554
555 const char *fdt_get_alias(const void *fdt, const char *name)
556 {
557 return fdt_get_alias_namelen(fdt, name, strlen(name));
558 }
559
560 const char *fdt_get_symbol_namelen(const void *fdt,
561 const char *name, int namelen)
562 {
563 return fdt_path_getprop_namelen(fdt, "/__symbols__", name, namelen, NULL);
564 }
565
566 const char *fdt_get_symbol(const void *fdt, const char *name)
567 {
568 return fdt_get_symbol_namelen(fdt, name, strlen(name));
569 }
570
571 int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen)
572 {
573 int pdepth = 0, p = 0;
574 int offset, depth, namelen;
575 const char *name;
576
577 FDT_RO_PROBE(fdt);
578
579 if (buflen < 2)
580 return -FDT_ERR_NOSPACE;
581
582 for (offset = 0, depth = 0;
583 (offset >= 0) && (offset <= nodeoffset);
584 offset = fdt_next_node(fdt, offset, &depth)) {
585 while (pdepth > depth) {
586 do {
587 p--;
588 } while (buf[p-1] != '/');
589 pdepth--;
590 }
591
592 if (pdepth >= depth) {
593 name = fdt_get_name(fdt, offset, &namelen);
594 if (!name)
595 return namelen;
596 if ((p + namelen + 1) <= buflen) {
597 memcpy(buf + p, name, namelen);
598 p += namelen;
599 buf[p++] = '/';
600 pdepth++;
601 }
602 }
603
604 if (offset == nodeoffset) {
605 if (pdepth < (depth + 1))
606 return -FDT_ERR_NOSPACE;
607
608 if (p > 1) /* special case so that root path is "/", not "" */
609 p--;
610 buf[p] = '\0';
611 return 0;
612 }
613 }
614
615 if ((offset == -FDT_ERR_NOTFOUND) || (offset >= 0))
616 return -FDT_ERR_BADOFFSET;
617 else if (offset == -FDT_ERR_BADOFFSET)
618 return -FDT_ERR_BADSTRUCTURE;
619
620 return offset; /* error from fdt_next_node() */
621 }
622
623 int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
624 int supernodedepth, int *nodedepth)
625 {
626 int offset, depth;
627 int supernodeoffset = -FDT_ERR_INTERNAL;
628
629 FDT_RO_PROBE(fdt);
630
631 if (supernodedepth < 0)
632 return -FDT_ERR_NOTFOUND;
633
634 for (offset = 0, depth = 0;
635 (offset >= 0) && (offset <= nodeoffset);
636 offset = fdt_next_node(fdt, offset, &depth)) {
637 if (depth == supernodedepth)
638 supernodeoffset = offset;
639
640 if (offset == nodeoffset) {
641 if (nodedepth)
642 *nodedepth = depth;
643
644 if (supernodedepth > depth)
645 return -FDT_ERR_NOTFOUND;
646 else
647 return supernodeoffset;
648 }
649 }
650
651 if (!can_assume(VALID_INPUT)) {
652 if ((offset == -FDT_ERR_NOTFOUND) || (offset >= 0))
653 return -FDT_ERR_BADOFFSET;
654 else if (offset == -FDT_ERR_BADOFFSET)
655 return -FDT_ERR_BADSTRUCTURE;
656 }
657
658 return offset; /* error from fdt_next_node() */
659 }
660
661 int fdt_node_depth(const void *fdt, int nodeoffset)
662 {
663 int nodedepth;
664 int err;
665
666 err = fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, &nodedepth);
667 if (err)
668 return (can_assume(LIBFDT_FLAWLESS) || err < 0) ? err :
669 -FDT_ERR_INTERNAL;
670 return nodedepth;
671 }
672
673 int fdt_parent_offset(const void *fdt, int nodeoffset)
674 {
675 int nodedepth = fdt_node_depth(fdt, nodeoffset);
676
677 if (nodedepth < 0)
678 return nodedepth;
679 return fdt_supernode_atdepth_offset(fdt, nodeoffset,
680 nodedepth - 1, NULL);
681 }
682
683 int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
684 const char *propname,
685 const void *propval, int proplen)
686 {
687 int offset;
688 const void *val;
689 int len;
690
691 FDT_RO_PROBE(fdt);
692
693 /* FIXME: The algorithm here is pretty horrible: we scan each
694 * property of a node in fdt_getprop(), then if that didn't
695 * find what we want, we scan over them again making our way
696 * to the next node. Still it's the easiest to implement
697 * approach; performance can come later. */
698 for (offset = fdt_next_node(fdt, startoffset, NULL);
699 offset >= 0;
700 offset = fdt_next_node(fdt, offset, NULL)) {
701 val = fdt_getprop(fdt, offset, propname, &len);
702 if (val && (len == proplen)
703 && (memcmp(val, propval, len) == 0))
704 return offset;
705 }
706
707 return offset; /* error from fdt_next_node() */
708 }
709
710 int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle)
711 {
712 int offset;
713
714 if ((phandle == 0) || (phandle == ~0U))
715 return -FDT_ERR_BADPHANDLE;
716
717 FDT_RO_PROBE(fdt);
718
719 /* FIXME: The algorithm here is pretty horrible: we
720 * potentially scan each property of a node in
721 * fdt_get_phandle(), then if that didn't find what
722 * we want, we scan over them again making our way to the next
723 * node. Still it's the easiest to implement approach;
724 * performance can come later. */
725 for (offset = fdt_next_node(fdt, -1, NULL);
726 offset >= 0;
727 offset = fdt_next_node(fdt, offset, NULL)) {
728 if (fdt_get_phandle(fdt, offset) == phandle)
729 return offset;
730 }
731
732 return offset; /* error from fdt_next_node() */
733 }
734
735 int fdt_stringlist_contains(const char *strlist, int listlen, const char *str)
736 {
737 int len = strlen(str);
738 const char *p;
739
740 while (listlen >= len) {
741 if (memcmp(str, strlist, len+1) == 0)
742 return 1;
743 p = memchr(strlist, '\0', listlen);
744 if (!p)
745 return 0; /* malformed strlist.. */
746 listlen -= (p-strlist) + 1;
747 strlist = p + 1;
748 }
749 return 0;
750 }
751
752 int fdt_stringlist_count(const void *fdt, int nodeoffset, const char *property)
753 {
754 const char *list, *end;
755 int length, count = 0;
756
757 list = fdt_getprop(fdt, nodeoffset, property, &length);
758 if (!list)
759 return length;
760
761 end = list + length;
762
763 while (list < end) {
764 length = strnlen(list, end - list) + 1;
765
766 /* Abort if the last string isn't properly NUL-terminated. */
767 if (list + length > end)
768 return -FDT_ERR_BADVALUE;
769
770 list += length;
771 count++;
772 }
773
774 return count;
775 }
776
777 int fdt_stringlist_search(const void *fdt, int nodeoffset, const char *property,
778 const char *string)
779 {
780 int length, len, idx = 0;
781 const char *list, *end;
782
783 list = fdt_getprop(fdt, nodeoffset, property, &length);
784 if (!list)
785 return length;
786
787 len = strlen(string) + 1;
788 end = list + length;
789
790 while (list < end) {
791 length = strnlen(list, end - list) + 1;
792
793 /* Abort if the last string isn't properly NUL-terminated. */
794 if (list + length > end)
795 return -FDT_ERR_BADVALUE;
796
797 if (length == len && memcmp(list, string, length) == 0)
798 return idx;
799
800 list += length;
801 idx++;
802 }
803
804 return -FDT_ERR_NOTFOUND;
805 }
806
807 const char *fdt_stringlist_get(const void *fdt, int nodeoffset,
808 const char *property, int idx,
809 int *lenp)
810 {
811 const char *list, *end;
812 int length;
813
814 list = fdt_getprop(fdt, nodeoffset, property, &length);
815 if (!list) {
816 if (lenp)
817 *lenp = length;
818
819 return NULL;
820 }
821
822 end = list + length;
823
824 while (list < end) {
825 length = strnlen(list, end - list) + 1;
826
827 /* Abort if the last string isn't properly NUL-terminated. */
828 if (list + length > end) {
829 if (lenp)
830 *lenp = -FDT_ERR_BADVALUE;
831
832 return NULL;
833 }
834
835 if (idx == 0) {
836 if (lenp)
837 *lenp = length - 1;
838
839 return list;
840 }
841
842 list += length;
843 idx--;
844 }
845
846 if (lenp)
847 *lenp = -FDT_ERR_NOTFOUND;
848
849 return NULL;
850 }
851
852 int fdt_node_check_compatible(const void *fdt, int nodeoffset,
853 const char *compatible)
854 {
855 const void *prop;
856 int len;
857
858 prop = fdt_getprop(fdt, nodeoffset, "compatible", &len);
859 if (!prop)
860 return len;
861
862 return !fdt_stringlist_contains(prop, len, compatible);
863 }
864
865 int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
866 const char *compatible)
867 {
868 int offset, err;
869
870 FDT_RO_PROBE(fdt);
871
872 /* FIXME: The algorithm here is pretty horrible: we scan each
873 * property of a node in fdt_node_check_compatible(), then if
874 * that didn't find what we want, we scan over them again
875 * making our way to the next node. Still it's the easiest to
876 * implement approach; performance can come later. */
877 for (offset = fdt_next_node(fdt, startoffset, NULL);
878 offset >= 0;
879 offset = fdt_next_node(fdt, offset, NULL)) {
880 err = fdt_node_check_compatible(fdt, offset, compatible);
881 if ((err < 0) && (err != -FDT_ERR_NOTFOUND))
882 return err;
883 else if (err == 0)
884 return offset;
885 }
886
887 return offset; /* error from fdt_next_node() */
888 }
889
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