Update libfdt from device tree compiler (dtc)

Update libfdt to commit 8eaf5e358366017aa2e846c5038d1aa19958314e from
the device tree compiler (dtc) project.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

libfdt/fdt_ro.c

@@ -2,19 +2,51 @@
  * libfdt - Flat Device Tree manipulation
  * Copyright (C) 2006 David Gibson, IBM Corporation.
  *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public License
- * as published by the Free Software Foundation; either version 2.1 of
- * the License, or (at your option) any later version.
+ * libfdt is dual licensed: you can use it either under the terms of
+ * the GPL, or the BSD license, at your option.
  *
- * This library is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
+ *  a) This library is free software; you can redistribute it and/or
+ *     modify it under the terms of the GNU General Public License as
+ *     published by the Free Software Foundation; either version 2 of the
+ *     License, or (at your option) any later version.
  *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *     This library is distributed in the hope that it will be useful,
+ *     but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *     GNU General Public License for more details.
+ *
+ *     You should have received a copy of the GNU General Public
+ *     License along with this library; if not, write to the Free
+ *     Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+ *     MA 02110-1301 USA
+ *
+ * Alternatively,
+ *
+ *  b) Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *     1. Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *     2. Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include "libfdt_env.h"
 
@@ -23,14 +55,15 @@
 
 #include "libfdt_internal.h"
 
-#define CHECK_HEADER(fdt)	{ \
-	int err; \
-	if ((err = fdt_check_header(fdt)) != 0) \
-		return err; \
-}
+#define CHECK_HEADER(fdt) \
+	{ \
+		int err; \
+		if ((err = fdt_check_header(fdt)) != 0) \
+			return err; \
+	}
 
-static int offset_streq(const void *fdt, int offset,
-			const char *s, int len)
+static int nodename_eq(const void *fdt, int offset,
+		       const char *s, int len)
 {
 	const char *p = fdt_offset_ptr(fdt, offset, len+1);
 
@@ -41,57 +74,36 @@ static int offset_streq(const void *fdt, int offset,
 	if (memcmp(p, s, len) != 0)
 		return 0;
 
-	if (p[len] != '\0')
+	if (p[len] == '\0')
+		return 1;
+	else if (!memchr(s, '@', len) && (p[len] == '@'))
+		return 1;
+	else
 		return 0;
-
-	return 1;
 }
 
-/*
- * Checks if the property name matches.
- */
-static int prop_name_eq(const void *fdt, int offset, const char *name,
-			struct fdt_property **prop, int *lenp)
-{
-	int namestroff, len;
-
-	*prop = fdt_offset_ptr_typed(fdt, offset, *prop);
-	if (! *prop)
-		return -FDT_ERR_BADSTRUCTURE;
-
-	namestroff = fdt32_to_cpu((*prop)->nameoff);
-	if (streq(fdt_string(fdt, namestroff), name)) {
-		len = fdt32_to_cpu((*prop)->len);
-		*prop = fdt_offset_ptr(fdt, offset,
-				       sizeof(**prop) + len);
-		if (*prop) {
-			if (lenp)
-				*lenp = len;
-			return 1;
-		} else
-			return -FDT_ERR_BADSTRUCTURE;
-	}
-	return 0;
-}
-
-/*
- * Return a pointer to the string at the given string offset.
- */
-char *fdt_string(const void *fdt, int stroffset)
+const char *fdt_string(const void *fdt, int stroffset)
 {
 	return (char *)fdt + fdt_off_dt_strings(fdt) + stroffset;
 }
 
-/*
- * Return the node offset of the node specified by:
- *   parentoffset - starting place (0 to start at the root)
- *   name         - name being searched for
- *   namelen      - length of the name: typically strlen(name)
- *
- * Notes:
- *   If the start node has subnodes, the subnodes are _not_ searched for the
- *     requested name.
- */
+int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size)
+{
+	CHECK_HEADER(fdt);
+	*address = fdt64_to_cpu(_fdt_mem_rsv(fdt, n)->address);
+	*size = fdt64_to_cpu(_fdt_mem_rsv(fdt, n)->size);
+	return 0;
+}
+
+int fdt_num_mem_rsv(const void *fdt)
+{
+	int i = 0;
+
+	while (fdt64_to_cpu(_fdt_mem_rsv(fdt, i)->size) != 0)
+		i++;
+	return i;
+}
+
 int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
 			       const char *name, int namelen)
 {
@@ -101,13 +113,13 @@ int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
 
 	CHECK_HEADER(fdt);
 
-	tag = fdt_next_tag(fdt, parentoffset, &nextoffset, NULL);
+	tag = fdt_next_tag(fdt, parentoffset, &nextoffset);
 	if (tag != FDT_BEGIN_NODE)
 		return -FDT_ERR_BADOFFSET;
 
 	do {
 		offset = nextoffset;
-		tag = fdt_next_tag(fdt, offset, &nextoffset, NULL);
+		tag = fdt_next_tag(fdt, offset, &nextoffset);
 
 		switch (tag) {
 		case FDT_END:
@@ -115,15 +127,10 @@ int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
 
 		case FDT_BEGIN_NODE:
 			level++;
-			/*
-			 * If we are nested down levels, ignore the strings
-			 * until we get back to the proper level.
-			 */
 			if (level != 1)
 				continue;
-
-			/* Return the offset if this is "our" string. */
-			if (offset_streq(fdt, offset+FDT_TAGSIZE, name, namelen))
+			if (nodename_eq(fdt, offset+FDT_TAGSIZE, name, namelen))
+				/* Found it! */
 				return offset;
 			break;
 
@@ -143,20 +150,13 @@ int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
 	return -FDT_ERR_NOTFOUND;
 }
 
-/*
- * See fdt_subnode_offset_namelen()
- */
 int fdt_subnode_offset(const void *fdt, int parentoffset,
 		       const char *name)
 {
 	return fdt_subnode_offset_namelen(fdt, parentoffset, name, strlen(name));
 }
 
-/*
- * Searches for the node corresponding to the given path and returns the
- * offset of that node.
- */
-int fdt_find_node_by_path(const void *fdt, const char *path)
+int fdt_path_offset(const void *fdt, const char *path)
 {
 	const char *end = path + strlen(path);
 	const char *p = path;
@@ -164,37 +164,21 @@ int fdt_find_node_by_path(const void *fdt, const char *path)
 
 	CHECK_HEADER(fdt);
 
-	/* Paths must be absolute */
 	if (*path != '/')
 		return -FDT_ERR_BADPATH;
 
-	/* Handle the root path: root offset is 0 */
-	if (strcmp(path, "/") == 0)
-		return 0;
-
 	while (*p) {
 		const char *q;
 
-		/* Skip path separator(s) */
 		while (*p == '/')
 			p++;
 		if (! *p)
-			return -FDT_ERR_BADPATH;
-
-		/*
-		 * Find the next path separator.  The characters between
-		 * p and q are the next segment of the the path to find.
-		 */
+			return offset;
 		q = strchr(p, '/');
 		if (! q)
 			q = end;
 
-		/*
-		 * Find the offset corresponding to the this path segment.
-		 */
 		offset = fdt_subnode_offset_namelen(fdt, offset, p, q-p);
-
-		/* Oops, error, abort abort abort */
 		if (offset < 0)
 			return offset;
 
@@ -204,17 +188,37 @@ int fdt_find_node_by_path(const void *fdt, const char *path)
 	return offset;
 }
 
-/*
- * Given the offset of a node and a name of a property in that node, return
- * a pointer to the property struct.
- */
-struct fdt_property *fdt_get_property(const void *fdt,
-				      int nodeoffset,
-				      const char *name, int *lenp)
+const char *fdt_get_name(const void *fdt, int nodeoffset, int *len)
+{
+	const struct fdt_node_header *nh;
+	int err;
+
+	if ((err = fdt_check_header(fdt)) != 0)
+		goto fail;
+
+	err = -FDT_ERR_BADOFFSET;
+	nh = fdt_offset_ptr(fdt, nodeoffset, sizeof(*nh));
+	if (!nh || (fdt32_to_cpu(nh->tag) != FDT_BEGIN_NODE))
+		goto fail;
+
+	if (len)
+		*len = strlen(nh->name);
+
+	return nh->name;
+
+ fail:
+	if (len)
+		*len = err;
+	return NULL;
+}
+
+const struct fdt_property *fdt_get_property(const void *fdt,
+					    int nodeoffset,
+					    const char *name, int *lenp)
 {
-	int level = 0;
 	uint32_t tag;
-	struct fdt_property *prop;
+	const struct fdt_property *prop;
+	int namestroff;
 	int offset, nextoffset;
 	int err;
 
@@ -225,63 +229,59 @@ struct fdt_property *fdt_get_property(const void *fdt,
 	if (nodeoffset % FDT_TAGSIZE)
 		goto fail;
 
-	tag = fdt_next_tag(fdt, nodeoffset, &nextoffset, NULL);
+	tag = fdt_next_tag(fdt, nodeoffset, &nextoffset);
 	if (tag != FDT_BEGIN_NODE)
 		goto fail;
 
 	do {
 		offset = nextoffset;
 
-		tag = fdt_next_tag(fdt, offset, &nextoffset, NULL);
+		tag = fdt_next_tag(fdt, offset, &nextoffset);
 		switch (tag) {
 		case FDT_END:
 			err = -FDT_ERR_TRUNCATED;
 			goto fail;
 
 		case FDT_BEGIN_NODE:
-			level++;
-			break;
-
 		case FDT_END_NODE:
-			level--;
+		case FDT_NOP:
 			break;
 
 		case FDT_PROP:
-			/*
-			 * If we are nested down levels, ignore the strings
-			 * until we get back to the proper level.
-			 */
-			if (level != 0)
-				continue;
-
-			err = prop_name_eq(fdt, offset, name, &prop, lenp);
-			if (err > 0)
-				return prop;
-			else if (err < 0)
+			err = -FDT_ERR_BADSTRUCTURE;
+			prop = fdt_offset_ptr(fdt, offset, sizeof(*prop));
+			if (! prop)
 				goto fail;
-			break;
+			namestroff = fdt32_to_cpu(prop->nameoff);
+			if (streq(fdt_string(fdt, namestroff), name)) {
+				/* Found it! */
+				int len = fdt32_to_cpu(prop->len);
+				prop = fdt_offset_ptr(fdt, offset,
+						      sizeof(*prop)+len);
+				if (! prop)
+					goto fail;
 
-		case FDT_NOP:
+				if (lenp)
+					*lenp = len;
+
+				return prop;
+			}
 			break;
 
 		default:
 			err = -FDT_ERR_BADSTRUCTURE;
 			goto fail;
 		}
-	} while (level >= 0);
+	} while ((tag != FDT_BEGIN_NODE) && (tag != FDT_END_NODE));
 
 	err = -FDT_ERR_NOTFOUND;
-fail:
+ fail:
 	if (lenp)
 		*lenp = err;
 	return NULL;
 }
 
-/*
- * Given the offset of a node and a name of a property in that node, return
- * a pointer to the property data (ONLY).
- */
-void *fdt_getprop(const void *fdt, int nodeoffset,
+const void *fdt_getprop(const void *fdt, int nodeoffset,
 		  const char *name, int *lenp)
 {
 	const struct fdt_property *prop;
@@ -290,130 +290,294 @@ void *fdt_getprop(const void *fdt, int nodeoffset,
 	if (! prop)
 		return NULL;
 
-	return (void *)prop->data;
+	return prop->data;
 }
 
-
-uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset, char **namep)
+uint32_t fdt_get_phandle(const void *fdt, int nodeoffset)
+{
+	const uint32_t *php;
+	int len;
+
+	php = fdt_getprop(fdt, nodeoffset, "linux,phandle", &len);
+	if (!php || (len != sizeof(*php)))
+		return 0;
+
+	return fdt32_to_cpu(*php);
+}
+
+int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen)
 {
-	const uint32_t *tagp, *lenp;
 	uint32_t tag;
-	const char *p;
+	int p = 0, overflow = 0;
+	int offset, nextoffset, namelen;
+	const char *name;
 
-	if (offset % FDT_TAGSIZE)
-		return -1;
+	CHECK_HEADER(fdt);
 
-	tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
-	if (! tagp)
-		return FDT_END; /* premature end */
-	tag = fdt32_to_cpu(*tagp);
-	offset += FDT_TAGSIZE;
+	tag = fdt_next_tag(fdt, 0, &nextoffset);
+	if (tag != FDT_BEGIN_NODE)
+		return -FDT_ERR_BADSTRUCTURE;
 
-	switch (tag) {
-	case FDT_BEGIN_NODE:
-		if(namep)
-			*namep = fdt_offset_ptr(fdt, offset, 1);
-
-		/* skip name */
-		do {
-			p = fdt_offset_ptr(fdt, offset++, 1);
-		} while (p && (*p != '\0'));
-		if (! p)
-			return FDT_END;
-		break;
-	case FDT_PROP:
-		lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
-		if (! lenp)
-			return FDT_END;
-		/*
-		 * Get the property and set the namep to the name.
-		 */
-		if(namep) {
-			struct fdt_property *prop;
-
-			prop = fdt_offset_ptr_typed(fdt, offset - FDT_TAGSIZE, prop);
-			if (! prop)
-				return -FDT_ERR_BADSTRUCTURE;
-			*namep = fdt_string(fdt, fdt32_to_cpu(prop->nameoff));
-		}
-		/* skip name offset, length and value */
-		offset += 2*FDT_TAGSIZE + fdt32_to_cpu(*lenp);
-		break;
-	}
-
-	if (nextoffset)
-		*nextoffset = ALIGN(offset, FDT_TAGSIZE);
-
-	return tag;
-}
-
-/*
- * Return the number of used reserve map entries and total slots available.
- */
-int fdt_num_reservemap(void *fdt, int *used, int *total)
-{
-	struct fdt_reserve_entry *re;
-	int  start;
-	int  end;
-	int  err = fdt_check_header(fdt);
-
-	if (err != 0)
-		return err;
-
-	start = fdt_off_mem_rsvmap(fdt);
-
-	/*
-	 * Convention is that the reserve map is before the dt_struct,
-	 * but it does not have to be.
-	 */
-	end = fdt_totalsize(fdt);
-	if (end > fdt_off_dt_struct(fdt))
-		end = fdt_off_dt_struct(fdt);
-	if (end > fdt_off_dt_strings(fdt))
-		end = fdt_off_dt_strings(fdt);
-
-	/*
-	 * Since the reserved area list is zero terminated, you get one fewer.
-	 */
-	if (total)
-		*total = ((end - start) / sizeof(struct fdt_reserve_entry)) - 1;
-
-	if (used) {
-		*used = 0;
-		while (start < end) {
-			re = (struct fdt_reserve_entry *)(fdt + start);
-			if (re->size == 0)
-				return 0;	/* zero size terminates the list */
-
-			*used += 1;
-			start += sizeof(struct fdt_reserve_entry);
-		}
-		/*
-		 * If we get here, there was no zero size termination.
-		 */
-		return -FDT_ERR_BADLAYOUT;
-	}
-	return 0;
-}
-
-/*
- * Return the nth reserve map entry.
- */
-int fdt_get_reservemap(void *fdt, int n, struct fdt_reserve_entry *re)
-{
-	int  used;
-	int  total;
-	int  err;
-
-	err = fdt_num_reservemap(fdt, &used, &total);
-	if (err != 0)
-		return err;
-
-	if (n >= total)
+	if (buflen < 2)
 		return -FDT_ERR_NOSPACE;
-	if (re) {
-		*re = *(struct fdt_reserve_entry *)
-			_fdt_offset_ptr(fdt, n * sizeof(struct fdt_reserve_entry));
+	buf[0] = '/';
+	p = 1;
+
+	while (nextoffset <= nodeoffset) {
+		offset = nextoffset;
+		tag = fdt_next_tag(fdt, offset, &nextoffset);
+		switch (tag) {
+		case FDT_END:
+			return -FDT_ERR_BADOFFSET;
+
+		case FDT_BEGIN_NODE:
+			name = fdt_get_name(fdt, offset, &namelen);
+			if (!name)
+				return namelen;
+			if (overflow || ((p + namelen + 1) > buflen)) {
+				overflow++;
+				break;
+			}
+			memcpy(buf + p, name, namelen);
+			p += namelen;
+			buf[p++] = '/';
+			break;
+
+		case FDT_END_NODE:
+			if (overflow) {
+				overflow--;
+				break;
+			}
+			do {
+				p--;
+			} while  (buf[p-1] != '/');
+			break;
+
+		case FDT_PROP:
+		case FDT_NOP:
+			break;
+
+		default:
+			return -FDT_ERR_BADSTRUCTURE;
+		}
+	}
+
+	if (overflow)
+		return -FDT_ERR_NOSPACE;
+
+	if (p > 1) /* special case so that root path is "/", not "" */
+		p--;
+	buf[p] = '\0';
+	return p;
+}
+
+int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
+				 int supernodedepth, int *nodedepth)
+{
+	int level = -1;
+	uint32_t tag;
+	int offset, nextoffset = 0;
+	int supernodeoffset = -FDT_ERR_INTERNAL;
+
+	CHECK_HEADER(fdt);
+
+	if (supernodedepth < 0)
+		return -FDT_ERR_NOTFOUND;
+
+	do {
+		offset = nextoffset;
+		tag = fdt_next_tag(fdt, offset, &nextoffset);
+		switch (tag) {
+		case FDT_END:
+			return -FDT_ERR_BADOFFSET;
+
+		case FDT_BEGIN_NODE:
+			level++;
+			if (level == supernodedepth)
+				supernodeoffset = offset;
+			break;
+
+		case FDT_END_NODE:
+			level--;
+			break;
+
+		case FDT_PROP:
+		case FDT_NOP:
+			break;
+
+		default:
+			return -FDT_ERR_BADSTRUCTURE;
+		}
+	} while (offset < nodeoffset);
+
+	if (nodedepth)
+		*nodedepth = level;
+
+	if (supernodedepth > level)
+		return -FDT_ERR_NOTFOUND;
+	return supernodeoffset;
+}
+
+int fdt_node_depth(const void *fdt, int nodeoffset)
+{
+	int nodedepth;
+	int err;
+
+	err = fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, &nodedepth);
+	if (err)
+		return (err < 0) ? err : -FDT_ERR_INTERNAL;
+	return nodedepth;
+}
+
+int fdt_parent_offset(const void *fdt, int nodeoffset)
+{
+	int nodedepth = fdt_node_depth(fdt, nodeoffset);
+
+	if (nodedepth < 0)
+		return nodedepth;
+	return fdt_supernode_atdepth_offset(fdt, nodeoffset,
+					    nodedepth - 1, NULL);
+}
+
+int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
+				  const char *propname,
+				  const void *propval, int proplen)
+{
+	uint32_t tag;
+	int offset, nextoffset;
+	const void *val;
+	int len;
+
+	CHECK_HEADER(fdt);
+
+	if (startoffset >= 0) {
+		tag = fdt_next_tag(fdt, startoffset, &nextoffset);
+		if (tag != FDT_BEGIN_NODE)
+			return -FDT_ERR_BADOFFSET;
+	} else {
+		nextoffset = 0;
+	}
+
+	/* FIXME: The algorithm here is pretty horrible: we scan each
+	 * property of a node in fdt_getprop(), then if that didn't
+	 * find what we want, we scan over them again making our way
+	 * to the next node.  Still it's the easiest to implement
+	 * approach; performance can come later. */
+	do {
+		offset = nextoffset;
+		tag = fdt_next_tag(fdt, offset, &nextoffset);
+
+		switch (tag) {
+		case FDT_BEGIN_NODE:
+			val = fdt_getprop(fdt, offset, propname, &len);
+			if (val
+			    && (len == proplen)
+			    && (memcmp(val, propval, len) == 0))
+				return offset;
+			break;
+
+		case FDT_PROP:
+		case FDT_END:
+		case FDT_END_NODE:
+		case FDT_NOP:
+			break;
+
+		default:
+			return -FDT_ERR_BADSTRUCTURE;
+		}
+	} while (tag != FDT_END);
+
+	return -FDT_ERR_NOTFOUND;
+}
+
+int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle)
+{
+	if ((phandle == 0) || (phandle == -1))
+		return -FDT_ERR_BADPHANDLE;
+	phandle = cpu_to_fdt32(phandle);
+	return fdt_node_offset_by_prop_value(fdt, -1, "linux,phandle",
+					     &phandle, sizeof(phandle));
+}
+
+int _stringlist_contains(const void *strlist, int listlen, const char *str)
+{
+	int len = strlen(str);
+	const void *p;
+
+	while (listlen >= len) {
+		if (memcmp(str, strlist, len+1) == 0)
+			return 1;
+		p = memchr(strlist, '\0', listlen);
+		if (!p)
+			return 0; /* malformed strlist.. */
+		listlen -= (p-strlist) + 1;
+		strlist = p + 1;
 	}
 	return 0;
 }
+
+int fdt_node_check_compatible(const void *fdt, int nodeoffset,
+			      const char *compatible)
+{
+	const void *prop;
+	int len;
+
+	prop = fdt_getprop(fdt, nodeoffset, "compatible", &len);
+	if (!prop)
+		return len;
+	if (_stringlist_contains(prop, len, compatible))
+		return 0;
+	else
+		return 1;
+}
+
+int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
+				  const char *compatible)
+{
+	uint32_t tag;
+	int offset, nextoffset;
+	int err;
+
+	CHECK_HEADER(fdt);
+
+	if (startoffset >= 0) {
+		tag = fdt_next_tag(fdt, startoffset, &nextoffset);
+		if (tag != FDT_BEGIN_NODE)
+			return -FDT_ERR_BADOFFSET;
+	} else {
+		nextoffset = 0;
+	}
+
+	/* FIXME: The algorithm here is pretty horrible: we scan each
+	 * property of a node in fdt_node_check_compatible(), then if
+	 * that didn't find what we want, we scan over them again
+	 * making our way to the next node.  Still it's the easiest to
+	 * implement approach; performance can come later. */
+	do {
+		offset = nextoffset;
+		tag = fdt_next_tag(fdt, offset, &nextoffset);
+
+		switch (tag) {
+		case FDT_BEGIN_NODE:
+			err = fdt_node_check_compatible(fdt, offset,
+							compatible);
+			if ((err < 0)
+			    && (err != -FDT_ERR_NOTFOUND))
+				return err;
+			else if (err == 0)
+				return offset;
+			break;
+
+		case FDT_PROP:
+		case FDT_END:
+		case FDT_END_NODE:
+		case FDT_NOP:
+			break;
+
+		default:
+			return -FDT_ERR_BADSTRUCTURE;
+		}
+	} while (tag != FDT_END);
+
+	return -FDT_ERR_NOTFOUND;
+}