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v6.13.7
  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
 13static 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
 34const 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
 94fail:
 95	if (lenp)
 96		*lenp = err;
 97	return NULL;
 98}
 99
100const char *fdt_string(const void *fdt, int stroffset)
101{
102	return fdt_get_string(fdt, stroffset, NULL);
103}
104
105static 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
114int 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
142int 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
160static 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
175int 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
189int 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
201static 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
225int 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
244int 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
250int 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
298int fdt_path_offset(const void *fdt, const char *path)
299{
300	return fdt_path_offset_namelen(fdt, path, strlen(path));
301}
302
303const 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
341int 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
351int 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
359static 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
381const 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
397static 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
428const 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
446const 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
454const 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
472const 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
505const 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
511uint32_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
528static 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
540const 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
555const char *fdt_get_alias(const void *fdt, const char *name)
556{
557	return fdt_get_alias_namelen(fdt, name, strlen(name));
558}
559
560const 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
566const char *fdt_get_symbol(const void *fdt, const char *name)
567{
568	return fdt_get_symbol_namelen(fdt, name, strlen(name));
569}
570
571int 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
623int 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
661int 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
673int 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
683int 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
710int 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
735int 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
752int 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
777int 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
807const 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
852int 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
865int 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}
v4.17
 
  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
 53#include <fdt.h>
 54#include <libfdt.h>
 55
 56#include "libfdt_internal.h"
 57
 58static int fdt_nodename_eq_(const void *fdt, int offset,
 59			    const char *s, int len)
 60{
 61	int olen;
 62	const char *p = fdt_get_name(fdt, offset, &olen);
 63
 64	if (!p || olen < len)
 65		/* short match */
 66		return 0;
 67
 68	if (memcmp(p, s, len) != 0)
 69		return 0;
 70
 71	if (p[len] == '\0')
 72		return 1;
 73	else if (!memchr(s, '@', len) && (p[len] == '@'))
 74		return 1;
 75	else
 76		return 0;
 77}
 78
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 79const char *fdt_string(const void *fdt, int stroffset)
 80{
 81	return (const char *)fdt + fdt_off_dt_strings(fdt) + stroffset;
 82}
 83
 84static int fdt_string_eq_(const void *fdt, int stroffset,
 85			  const char *s, int len)
 86{
 87	const char *p = fdt_string(fdt, stroffset);
 
 88
 89	return (strlen(p) == len) && (memcmp(p, s, len) == 0);
 90}
 91
 92uint32_t fdt_get_max_phandle(const void *fdt)
 93{
 94	uint32_t max_phandle = 0;
 95	int offset;
 96
 97	for (offset = fdt_next_node(fdt, -1, NULL);;
 98	     offset = fdt_next_node(fdt, offset, NULL)) {
 99		uint32_t phandle;
100
101		if (offset == -FDT_ERR_NOTFOUND)
102			return max_phandle;
 
 
103
104		if (offset < 0)
105			return (uint32_t)-1;
106
107		phandle = fdt_get_phandle(fdt, offset);
108		if (phandle == (uint32_t)-1)
109			continue;
110
111		if (phandle > max_phandle)
112			max_phandle = phandle;
113	}
114
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
115	return 0;
116}
117
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
118int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size)
119{
120	FDT_CHECK_HEADER(fdt);
121	*address = fdt64_to_cpu(fdt_mem_rsv_(fdt, n)->address);
122	*size = fdt64_to_cpu(fdt_mem_rsv_(fdt, n)->size);
 
 
 
 
 
 
123	return 0;
124}
125
126int fdt_num_mem_rsv(const void *fdt)
127{
128	int i = 0;
 
129
130	while (fdt64_to_cpu(fdt_mem_rsv_(fdt, i)->size) != 0)
131		i++;
132	return i;
 
 
133}
134
135static int nextprop_(const void *fdt, int offset)
136{
137	uint32_t tag;
138	int nextoffset;
139
140	do {
141		tag = fdt_next_tag(fdt, offset, &nextoffset);
142
143		switch (tag) {
144		case FDT_END:
145			if (nextoffset >= 0)
146				return -FDT_ERR_BADSTRUCTURE;
147			else
148				return nextoffset;
149
150		case FDT_PROP:
151			return offset;
152		}
153		offset = nextoffset;
154	} while (tag == FDT_NOP);
155
156	return -FDT_ERR_NOTFOUND;
157}
158
159int fdt_subnode_offset_namelen(const void *fdt, int offset,
160			       const char *name, int namelen)
161{
162	int depth;
163
164	FDT_CHECK_HEADER(fdt);
165
166	for (depth = 0;
167	     (offset >= 0) && (depth >= 0);
168	     offset = fdt_next_node(fdt, offset, &depth))
169		if ((depth == 1)
170		    && fdt_nodename_eq_(fdt, offset, name, namelen))
171			return offset;
172
173	if (depth < 0)
174		return -FDT_ERR_NOTFOUND;
175	return offset; /* error */
176}
177
178int fdt_subnode_offset(const void *fdt, int parentoffset,
179		       const char *name)
180{
181	return fdt_subnode_offset_namelen(fdt, parentoffset, name, strlen(name));
182}
183
184int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen)
185{
186	const char *end = path + namelen;
187	const char *p = path;
188	int offset = 0;
189
190	FDT_CHECK_HEADER(fdt);
 
 
 
191
192	/* see if we have an alias */
193	if (*path != '/') {
194		const char *q = memchr(path, '/', end - p);
195
196		if (!q)
197			q = end;
198
199		p = fdt_get_alias_namelen(fdt, p, q - p);
200		if (!p)
201			return -FDT_ERR_BADPATH;
202		offset = fdt_path_offset(fdt, p);
203
204		p = q;
205	}
206
207	while (p < end) {
208		const char *q;
209
210		while (*p == '/') {
211			p++;
212			if (p == end)
213				return offset;
214		}
215		q = memchr(p, '/', end - p);
216		if (! q)
217			q = end;
218
219		offset = fdt_subnode_offset_namelen(fdt, offset, p, q-p);
220		if (offset < 0)
221			return offset;
222
223		p = q;
224	}
225
226	return offset;
227}
228
229int fdt_path_offset(const void *fdt, const char *path)
230{
231	return fdt_path_offset_namelen(fdt, path, strlen(path));
232}
233
234const char *fdt_get_name(const void *fdt, int nodeoffset, int *len)
235{
236	const struct fdt_node_header *nh = fdt_offset_ptr_(fdt, nodeoffset);
237	const char *nameptr;
238	int err;
239
240	if (((err = fdt_check_header(fdt)) != 0)
241	    || ((err = fdt_check_node_offset_(fdt, nodeoffset)) < 0))
242			goto fail;
243
244	nameptr = nh->name;
245
246	if (fdt_version(fdt) < 0x10) {
247		/*
248		 * For old FDT versions, match the naming conventions of V16:
249		 * give only the leaf name (after all /). The actual tree
250		 * contents are loosely checked.
251		 */
252		const char *leaf;
253		leaf = strrchr(nameptr, '/');
254		if (leaf == NULL) {
255			err = -FDT_ERR_BADSTRUCTURE;
256			goto fail;
257		}
258		nameptr = leaf+1;
259	}
260
261	if (len)
262		*len = strlen(nameptr);
263
264	return nameptr;
265
266 fail:
267	if (len)
268		*len = err;
269	return NULL;
270}
271
272int fdt_first_property_offset(const void *fdt, int nodeoffset)
273{
274	int offset;
275
276	if ((offset = fdt_check_node_offset_(fdt, nodeoffset)) < 0)
277		return offset;
278
279	return nextprop_(fdt, offset);
280}
281
282int fdt_next_property_offset(const void *fdt, int offset)
283{
284	if ((offset = fdt_check_prop_offset_(fdt, offset)) < 0)
285		return offset;
286
287	return nextprop_(fdt, offset);
288}
289
290static const struct fdt_property *fdt_get_property_by_offset_(const void *fdt,
291						              int offset,
292						              int *lenp)
293{
294	int err;
295	const struct fdt_property *prop;
296
297	if ((err = fdt_check_prop_offset_(fdt, offset)) < 0) {
 
298		if (lenp)
299			*lenp = err;
300		return NULL;
301	}
302
303	prop = fdt_offset_ptr_(fdt, offset);
304
305	if (lenp)
306		*lenp = fdt32_to_cpu(prop->len);
307
308	return prop;
309}
310
311const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
312						      int offset,
313						      int *lenp)
314{
315	/* Prior to version 16, properties may need realignment
316	 * and this API does not work. fdt_getprop_*() will, however. */
317
318	if (fdt_version(fdt) < 0x10) {
319		if (lenp)
320			*lenp = -FDT_ERR_BADVERSION;
321		return NULL;
322	}
323
324	return fdt_get_property_by_offset_(fdt, offset, lenp);
325}
326
327static const struct fdt_property *fdt_get_property_namelen_(const void *fdt,
328						            int offset,
329						            const char *name,
330						            int namelen,
331							    int *lenp,
332							    int *poffset)
333{
334	for (offset = fdt_first_property_offset(fdt, offset);
335	     (offset >= 0);
336	     (offset = fdt_next_property_offset(fdt, offset))) {
337		const struct fdt_property *prop;
338
339		if (!(prop = fdt_get_property_by_offset_(fdt, offset, lenp))) {
 
340			offset = -FDT_ERR_INTERNAL;
341			break;
342		}
343		if (fdt_string_eq_(fdt, fdt32_to_cpu(prop->nameoff),
344				   name, namelen)) {
345			if (poffset)
346				*poffset = offset;
347			return prop;
348		}
349	}
350
351	if (lenp)
352		*lenp = offset;
353	return NULL;
354}
355
356
357const struct fdt_property *fdt_get_property_namelen(const void *fdt,
358						    int offset,
359						    const char *name,
360						    int namelen, int *lenp)
361{
362	/* Prior to version 16, properties may need realignment
363	 * and this API does not work. fdt_getprop_*() will, however. */
364	if (fdt_version(fdt) < 0x10) {
365		if (lenp)
366			*lenp = -FDT_ERR_BADVERSION;
367		return NULL;
368	}
369
370	return fdt_get_property_namelen_(fdt, offset, name, namelen, lenp,
371					 NULL);
372}
373
374
375const struct fdt_property *fdt_get_property(const void *fdt,
376					    int nodeoffset,
377					    const char *name, int *lenp)
378{
379	return fdt_get_property_namelen(fdt, nodeoffset, name,
380					strlen(name), lenp);
381}
382
383const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
384				const char *name, int namelen, int *lenp)
385{
386	int poffset;
387	const struct fdt_property *prop;
388
389	prop = fdt_get_property_namelen_(fdt, nodeoffset, name, namelen, lenp,
390					 &poffset);
391	if (!prop)
392		return NULL;
393
394	/* Handle realignment */
395	if (fdt_version(fdt) < 0x10 && (poffset + sizeof(*prop)) % 8 &&
396	    fdt32_to_cpu(prop->len) >= 8)
397		return prop->data + 4;
398	return prop->data;
399}
400
401const void *fdt_getprop_by_offset(const void *fdt, int offset,
402				  const char **namep, int *lenp)
403{
404	const struct fdt_property *prop;
405
406	prop = fdt_get_property_by_offset_(fdt, offset, lenp);
407	if (!prop)
408		return NULL;
409	if (namep)
410		*namep = fdt_string(fdt, fdt32_to_cpu(prop->nameoff));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
411
412	/* Handle realignment */
413	if (fdt_version(fdt) < 0x10 && (offset + sizeof(*prop)) % 8 &&
414	    fdt32_to_cpu(prop->len) >= 8)
415		return prop->data + 4;
416	return prop->data;
417}
418
419const void *fdt_getprop(const void *fdt, int nodeoffset,
420			const char *name, int *lenp)
421{
422	return fdt_getprop_namelen(fdt, nodeoffset, name, strlen(name), lenp);
423}
424
425uint32_t fdt_get_phandle(const void *fdt, int nodeoffset)
426{
427	const fdt32_t *php;
428	int len;
429
430	/* FIXME: This is a bit sub-optimal, since we potentially scan
431	 * over all the properties twice. */
432	php = fdt_getprop(fdt, nodeoffset, "phandle", &len);
433	if (!php || (len != sizeof(*php))) {
434		php = fdt_getprop(fdt, nodeoffset, "linux,phandle", &len);
435		if (!php || (len != sizeof(*php)))
436			return 0;
437	}
438
439	return fdt32_to_cpu(*php);
 
 
 
 
 
 
 
 
 
 
 
 
440}
441
442const char *fdt_get_alias_namelen(const void *fdt,
443				  const char *name, int namelen)
444{
445	int aliasoffset;
 
446
447	aliasoffset = fdt_path_offset(fdt, "/aliases");
448	if (aliasoffset < 0)
 
 
449		return NULL;
450
451	return fdt_getprop_namelen(fdt, aliasoffset, name, namelen, NULL);
452}
453
454const char *fdt_get_alias(const void *fdt, const char *name)
455{
456	return fdt_get_alias_namelen(fdt, name, strlen(name));
457}
458
 
 
 
 
 
 
 
 
 
 
 
459int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen)
460{
461	int pdepth = 0, p = 0;
462	int offset, depth, namelen;
463	const char *name;
464
465	FDT_CHECK_HEADER(fdt);
466
467	if (buflen < 2)
468		return -FDT_ERR_NOSPACE;
469
470	for (offset = 0, depth = 0;
471	     (offset >= 0) && (offset <= nodeoffset);
472	     offset = fdt_next_node(fdt, offset, &depth)) {
473		while (pdepth > depth) {
474			do {
475				p--;
476			} while (buf[p-1] != '/');
477			pdepth--;
478		}
479
480		if (pdepth >= depth) {
481			name = fdt_get_name(fdt, offset, &namelen);
482			if (!name)
483				return namelen;
484			if ((p + namelen + 1) <= buflen) {
485				memcpy(buf + p, name, namelen);
486				p += namelen;
487				buf[p++] = '/';
488				pdepth++;
489			}
490		}
491
492		if (offset == nodeoffset) {
493			if (pdepth < (depth + 1))
494				return -FDT_ERR_NOSPACE;
495
496			if (p > 1) /* special case so that root path is "/", not "" */
497				p--;
498			buf[p] = '\0';
499			return 0;
500		}
501	}
502
503	if ((offset == -FDT_ERR_NOTFOUND) || (offset >= 0))
504		return -FDT_ERR_BADOFFSET;
505	else if (offset == -FDT_ERR_BADOFFSET)
506		return -FDT_ERR_BADSTRUCTURE;
507
508	return offset; /* error from fdt_next_node() */
509}
510
511int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
512				 int supernodedepth, int *nodedepth)
513{
514	int offset, depth;
515	int supernodeoffset = -FDT_ERR_INTERNAL;
516
517	FDT_CHECK_HEADER(fdt);
518
519	if (supernodedepth < 0)
520		return -FDT_ERR_NOTFOUND;
521
522	for (offset = 0, depth = 0;
523	     (offset >= 0) && (offset <= nodeoffset);
524	     offset = fdt_next_node(fdt, offset, &depth)) {
525		if (depth == supernodedepth)
526			supernodeoffset = offset;
527
528		if (offset == nodeoffset) {
529			if (nodedepth)
530				*nodedepth = depth;
531
532			if (supernodedepth > depth)
533				return -FDT_ERR_NOTFOUND;
534			else
535				return supernodeoffset;
536		}
537	}
538
539	if ((offset == -FDT_ERR_NOTFOUND) || (offset >= 0))
540		return -FDT_ERR_BADOFFSET;
541	else if (offset == -FDT_ERR_BADOFFSET)
542		return -FDT_ERR_BADSTRUCTURE;
 
 
543
544	return offset; /* error from fdt_next_node() */
545}
546
547int fdt_node_depth(const void *fdt, int nodeoffset)
548{
549	int nodedepth;
550	int err;
551
552	err = fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, &nodedepth);
553	if (err)
554		return (err < 0) ? err : -FDT_ERR_INTERNAL;
 
555	return nodedepth;
556}
557
558int fdt_parent_offset(const void *fdt, int nodeoffset)
559{
560	int nodedepth = fdt_node_depth(fdt, nodeoffset);
561
562	if (nodedepth < 0)
563		return nodedepth;
564	return fdt_supernode_atdepth_offset(fdt, nodeoffset,
565					    nodedepth - 1, NULL);
566}
567
568int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
569				  const char *propname,
570				  const void *propval, int proplen)
571{
572	int offset;
573	const void *val;
574	int len;
575
576	FDT_CHECK_HEADER(fdt);
577
578	/* FIXME: The algorithm here is pretty horrible: we scan each
579	 * property of a node in fdt_getprop(), then if that didn't
580	 * find what we want, we scan over them again making our way
581	 * to the next node.  Still it's the easiest to implement
582	 * approach; performance can come later. */
583	for (offset = fdt_next_node(fdt, startoffset, NULL);
584	     offset >= 0;
585	     offset = fdt_next_node(fdt, offset, NULL)) {
586		val = fdt_getprop(fdt, offset, propname, &len);
587		if (val && (len == proplen)
588		    && (memcmp(val, propval, len) == 0))
589			return offset;
590	}
591
592	return offset; /* error from fdt_next_node() */
593}
594
595int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle)
596{
597	int offset;
598
599	if ((phandle == 0) || (phandle == -1))
600		return -FDT_ERR_BADPHANDLE;
601
602	FDT_CHECK_HEADER(fdt);
603
604	/* FIXME: The algorithm here is pretty horrible: we
605	 * potentially scan each property of a node in
606	 * fdt_get_phandle(), then if that didn't find what
607	 * we want, we scan over them again making our way to the next
608	 * node.  Still it's the easiest to implement approach;
609	 * performance can come later. */
610	for (offset = fdt_next_node(fdt, -1, NULL);
611	     offset >= 0;
612	     offset = fdt_next_node(fdt, offset, NULL)) {
613		if (fdt_get_phandle(fdt, offset) == phandle)
614			return offset;
615	}
616
617	return offset; /* error from fdt_next_node() */
618}
619
620int fdt_stringlist_contains(const char *strlist, int listlen, const char *str)
621{
622	int len = strlen(str);
623	const char *p;
624
625	while (listlen >= len) {
626		if (memcmp(str, strlist, len+1) == 0)
627			return 1;
628		p = memchr(strlist, '\0', listlen);
629		if (!p)
630			return 0; /* malformed strlist.. */
631		listlen -= (p-strlist) + 1;
632		strlist = p + 1;
633	}
634	return 0;
635}
636
637int fdt_stringlist_count(const void *fdt, int nodeoffset, const char *property)
638{
639	const char *list, *end;
640	int length, count = 0;
641
642	list = fdt_getprop(fdt, nodeoffset, property, &length);
643	if (!list)
644		return length;
645
646	end = list + length;
647
648	while (list < end) {
649		length = strnlen(list, end - list) + 1;
650
651		/* Abort if the last string isn't properly NUL-terminated. */
652		if (list + length > end)
653			return -FDT_ERR_BADVALUE;
654
655		list += length;
656		count++;
657	}
658
659	return count;
660}
661
662int fdt_stringlist_search(const void *fdt, int nodeoffset, const char *property,
663			  const char *string)
664{
665	int length, len, idx = 0;
666	const char *list, *end;
667
668	list = fdt_getprop(fdt, nodeoffset, property, &length);
669	if (!list)
670		return length;
671
672	len = strlen(string) + 1;
673	end = list + length;
674
675	while (list < end) {
676		length = strnlen(list, end - list) + 1;
677
678		/* Abort if the last string isn't properly NUL-terminated. */
679		if (list + length > end)
680			return -FDT_ERR_BADVALUE;
681
682		if (length == len && memcmp(list, string, length) == 0)
683			return idx;
684
685		list += length;
686		idx++;
687	}
688
689	return -FDT_ERR_NOTFOUND;
690}
691
692const char *fdt_stringlist_get(const void *fdt, int nodeoffset,
693			       const char *property, int idx,
694			       int *lenp)
695{
696	const char *list, *end;
697	int length;
698
699	list = fdt_getprop(fdt, nodeoffset, property, &length);
700	if (!list) {
701		if (lenp)
702			*lenp = length;
703
704		return NULL;
705	}
706
707	end = list + length;
708
709	while (list < end) {
710		length = strnlen(list, end - list) + 1;
711
712		/* Abort if the last string isn't properly NUL-terminated. */
713		if (list + length > end) {
714			if (lenp)
715				*lenp = -FDT_ERR_BADVALUE;
716
717			return NULL;
718		}
719
720		if (idx == 0) {
721			if (lenp)
722				*lenp = length - 1;
723
724			return list;
725		}
726
727		list += length;
728		idx--;
729	}
730
731	if (lenp)
732		*lenp = -FDT_ERR_NOTFOUND;
733
734	return NULL;
735}
736
737int fdt_node_check_compatible(const void *fdt, int nodeoffset,
738			      const char *compatible)
739{
740	const void *prop;
741	int len;
742
743	prop = fdt_getprop(fdt, nodeoffset, "compatible", &len);
744	if (!prop)
745		return len;
746
747	return !fdt_stringlist_contains(prop, len, compatible);
748}
749
750int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
751				  const char *compatible)
752{
753	int offset, err;
754
755	FDT_CHECK_HEADER(fdt);
756
757	/* FIXME: The algorithm here is pretty horrible: we scan each
758	 * property of a node in fdt_node_check_compatible(), then if
759	 * that didn't find what we want, we scan over them again
760	 * making our way to the next node.  Still it's the easiest to
761	 * implement approach; performance can come later. */
762	for (offset = fdt_next_node(fdt, startoffset, NULL);
763	     offset >= 0;
764	     offset = fdt_next_node(fdt, offset, NULL)) {
765		err = fdt_node_check_compatible(fdt, offset, compatible);
766		if ((err < 0) && (err != -FDT_ERR_NOTFOUND))
767			return err;
768		else if (err == 0)
769			return offset;
770	}
771
772	return offset; /* error from fdt_next_node() */
773}