libfdt: Add helper function to create a trivial, empty tree
authorGerald Van Baren <gvb@unssw.com>
Tue, 16 Oct 2012 02:24:36 +0000 (22:24 -0400)
committerGerald Van Baren <gvb@unssw.com>
Tue, 16 Oct 2012 02:24:36 +0000 (22:24 -0400)
commitc71b64f3617b5a4362c6e4e0aefdd66d6ac6affd
tree947b4febb1b863d9028274c064da2f698b803120
parent8ac88f2d2818c8efc1558626a4e7fb47dcc18987
libfdt: Add helper function to create a trivial, empty tree

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>
include/libfdt.h
lib/libfdt/Makefile
lib/libfdt/fdt_empty_tree.c [new file with mode: 0644]