fdt_ro.c

/*
 * 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"

static int check_header(const struct fdt_header *fdt)
{
	if (fdt_magic(fdt) == FDT_MAGIC) {
		/* Complete tree */
		if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
			return FDT_ERR_BADVERSION;
		if (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION)
			return FDT_ERR_BADVERSION;
	} else if (fdt_magic(fdt) == SW_MAGIC) {
		/* Unfinished sequential-write blob */
		if (sw_size_dt_struct(fdt) == 0)
			return FDT_ERR_BADSTATE;
	} else {
		return FDT_ERR_BADMAGIC;
	}

	return 0;
}

#define OFFSET_CHECK_HEADER(fdt) \
	{ \
		int err; \
		if ((err = check_header(fdt)) != 0) \
			return OFFSET_ERROR(err); \
	}

static int offset_streq(const struct fdt_header *fdt, int offset,
			const char *s, int len)
{
	const char *p = fdt_offset_ptr(fdt, offset, len+1);

	if (! p)
		/* short match */
		return 0;

	if (memcmp(p, s, len) != 0)
		return 0;

	if (p[len] != '\0')
		return 0;

	return 1;
}

char *fdt_string(const struct fdt_header *fdt, int stroffset)
{
	return (char *)fdt + fdt_off_dt_strings(fdt) + stroffset;
}

int fdt_property_offset(const struct fdt_header *fdt, int nodeoffset,
			const char *name)
{
	int level = 0;
	uint32_t tag;
	struct fdt_property *prop;
	int namestroff;
	int offset, nextoffset;

	OFFSET_CHECK_HEADER(fdt);

	if (nodeoffset % FDT_TAGSIZE)
		return OFFSET_ERROR(FDT_ERR_BADOFFSET);

	tag = _fdt_next_tag(fdt, nodeoffset, &nextoffset);
	if (tag != FDT_BEGIN_NODE)
		return OFFSET_ERROR(FDT_ERR_BADOFFSET);

	do {
		offset = nextoffset;
		if (offset % FDT_TAGSIZE)
			return OFFSET_ERROR(FDT_ERR_INTERNAL);

		tag = _fdt_next_tag(fdt, offset, &nextoffset);
		switch (tag) {
		case FDT_END:
			return OFFSET_ERROR(FDT_ERR_TRUNCATED);

		case FDT_BEGIN_NODE:
			level++;
			break;

		case FDT_END_NODE:
			level--;
			break;

		case FDT_PROP:
			if (level != 0)
				continue;

			prop = fdt_offset_ptr_typed(fdt, offset, prop);
			if (! prop)
				return OFFSET_ERROR(FDT_ERR_BADSTRUCTURE);
			namestroff = fdt32_to_cpu(prop->nameoff);
			if (streq(fdt_string(fdt, namestroff), name))
				/* Found it! */
				return offset;
			break;

		case FDT_NOP:
			break;

		default:
			return OFFSET_ERROR(FDT_ERR_BADSTRUCTURE);
		}
	} while (level >= 0);

	return OFFSET_ERROR(FDT_ERR_NOTFOUND);
}

int fdt_subnode_offset_namelen(const struct fdt_header *fdt, int parentoffset,
			       const char *name, int namelen)
{
	int level = 0;
	uint32_t tag;
	int offset, nextoffset;

	OFFSET_CHECK_HEADER(fdt);

	tag = _fdt_next_tag(fdt, parentoffset, &nextoffset);
	if (tag != FDT_BEGIN_NODE)
		return OFFSET_ERROR(FDT_ERR_BADOFFSET);

	do {
		offset = nextoffset;
		tag = _fdt_next_tag(fdt, offset, &nextoffset);

		switch (tag) {
		case FDT_END:
			return OFFSET_ERROR(FDT_ERR_TRUNCATED);

		case FDT_BEGIN_NODE:
			level++;
			if (level != 1)
				continue;
			if (offset_streq(fdt, offset+FDT_TAGSIZE, name, namelen))
				/* Found it! */
				return offset;
			break;

		case FDT_END_NODE:
			level--;
			break;

		case FDT_PROP:
		case FDT_NOP:
			break;

		default:
			return OFFSET_ERROR(FDT_ERR_BADSTRUCTURE);
		}
	} while (level >= 0);

	return OFFSET_ERROR(FDT_ERR_NOTFOUND);
}

int fdt_subnode_offset(const struct fdt_header *fdt, int parentoffset,
		       const char *name)
{
	return fdt_subnode_offset_namelen(fdt, parentoffset, name, strlen(name));
}

int fdt_path_offset(const struct fdt_header *fdt, const char *path)
{
	const char *end = path + strlen(path);
	const char *p = path;
	int offset = 0;

	OFFSET_CHECK_HEADER(fdt);

	if (*path != '/')
		return OFFSET_ERROR(FDT_ERR_BADPATH);

	while (*p) {
		const char *q;

		while (*p == '/')
			p++;
		if (! *p)
			return OFFSET_ERROR(FDT_ERR_BADPATH);
		q = strchr(p, '/');
		if (! q)
			q = end;

		offset = fdt_subnode_offset_namelen(fdt, offset, p, q-p);
		if (fdt_offset_error(offset))
			return offset;

		p = q;
	}

	return offset;	
}

struct fdt_property *_fdt_getprop(const struct fdt_header *fdt, int nodeoffset,
				  const char *name, int *lenp)
{
	int propoffset;
	struct fdt_property *prop;
	int err;
	int len;

	propoffset = fdt_property_offset(fdt, nodeoffset, name);
	if ((err = fdt_offset_error(propoffset)))
		return PTR_ERROR(err);

	prop = fdt_offset_ptr(fdt, propoffset, sizeof(prop));
	if (! prop)
		return PTR_ERROR(FDT_ERR_BADSTRUCTURE);
	len = fdt32_to_cpu(prop->len);
	prop = fdt_offset_ptr(fdt, propoffset, sizeof(prop) + len);
	if (! prop)
		return PTR_ERROR(FDT_ERR_BADSTRUCTURE);

	if (lenp)
		*lenp = len;

	return prop;
}

void *fdt_getprop(const struct fdt_header *fdt, int nodeoffset,
		  const char *name, int *lenp)
{
	const struct fdt_property *prop;
	int err;

	prop = _fdt_getprop(fdt, nodeoffset, name, lenp);
	if ((err = fdt_ptr_error(prop)))
		return PTR_ERROR(err);

	return prop->data;
}