libfdt - library for manipulating device trees in flattened format

Initial revision, read-only and "in-place" (no memmove() required)
write operations only.

fdt.c

@@ -0,0 +1,94 @@
+/*
+ * 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.
+ *
+ * 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.
+ *
+ * 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
+ */
+#include "libfdt_env.h"
+
+#include <fdt.h>
+#include <libfdt.h>
+
+#include "libfdt_internal.h"
+
+void *fdt_offset_ptr(const struct fdt_header *fdt, int offset, int len)
+{
+	void *p;
+
+	p = (void *)fdt + fdt32_to_cpu(fdt->off_dt_struct) + offset;
+
+	if (p + len < p)
+		return NULL;
+	return p;
+}
+
+char *fdt_string(const struct fdt_header *fdt, int stroffset)
+{
+	return (char *)fdt + fdt32_to_cpu(fdt->off_dt_strings) + stroffset;
+}
+
+int fdt_string_cmp(const struct fdt_header *fdt, int stroffset, const char *s2)
+{
+	const char *s1 = fdt_string(fdt, stroffset);
+	int len = strlen(s2) + 1;
+
+	if (! s1)
+		return 0;
+
+	if ((stroffset + len < stroffset)
+	    || (stroffset + len > fdt32_to_cpu(fdt->size_dt_strings)))
+		return -2;
+
+	return strcmp(s1, s2);
+}
+
+uint32_t _fdt_next_tag(const struct fdt_header *fdt, int offset, int *nextoffset)
+{
+	const uint32_t *tagp, *lenp;
+	uint32_t tag;
+	const char *p;
+
+	if (offset % FDT_TAGSIZE)
+		return -1;
+
+	tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
+	if (! tagp)
+		return FDT_END; /* premature end */
+	tag = fdt32_to_cpu(*tagp);
+	offset += FDT_TAGSIZE;
+
+	switch (tag) {
+	case FDT_BEGIN_NODE:
+		/* 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 + FDT_TAGSIZE, sizeof(*lenp));
+		if (! lenp)
+			return FDT_END;
+		/* skip name offset, length and value */
+		offset += 2*FDT_TAGSIZE + fdt32_to_cpu(*lenp);
+		break;
+	}
+
+	if (nextoffset)
+		*nextoffset = ALIGN(offset, FDT_TAGSIZE);
+
+	return tag;
+}