mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-09-07 13:23:20 +09:00
![Gerald Van Baren](/assets/img/avatar_default.png)
The libfdt read/write functions are now usable enough that it's become a moderately common pattern to use them to build and manipulate a device tree from scratch. For example, we do so ourself in our rw_tree1 testcase, and qemu is starting to use this model when building device trees for some targets such as e500. However, the read/write functions require some sort of valid tree to begin with, so this necessitates either having a trivial canned dtb to begin with or, more commonly, creating an empty tree using the serial-write functions first. This patch adds a helper function which uses the serial-write functions to create a trivial, empty but complete and valid tree in a supplied buffer, ready for manipulation with the read/write functions. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> From git://git.jdl.com/software/dtc.git patch hash be6026838 with adaptations to include/libfdt.h and lib/libfdt/Makefile for the U-Boot environment. Signed-off-by: Gerald Van Baren <vanbaren@cideas.com>
85 lines
2.8 KiB
C
85 lines
2.8 KiB
C
/*
|
|
* libfdt - Flat Device Tree manipulation
|
|
* Copyright (C) 2012 David Gibson, IBM Corporation.
|
|
*
|
|
* libfdt is dual licensed: you can use it either under the terms of
|
|
* the GPL, or the BSD license, at your option.
|
|
*
|
|
* 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.
|
|
*
|
|
* 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"
|
|
|
|
#include <fdt.h>
|
|
#include <libfdt.h>
|
|
|
|
#include "libfdt_internal.h"
|
|
|
|
int fdt_create_empty_tree(void *buf, int bufsize)
|
|
{
|
|
int err;
|
|
|
|
err = fdt_create(buf, bufsize);
|
|
if (err)
|
|
return err;
|
|
|
|
err = fdt_finish_reservemap(buf);
|
|
if (err)
|
|
return err;
|
|
|
|
err = fdt_begin_node(buf, "");
|
|
if (err)
|
|
return err;
|
|
|
|
err = fdt_end_node(buf);
|
|
if (err)
|
|
return err;
|
|
|
|
err = fdt_finish(buf);
|
|
if (err)
|
|
return err;
|
|
|
|
return fdt_open_into(buf, buf, bufsize);
|
|
}
|
|
|