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>
diff --git a/include/libfdt.h b/include/libfdt.h
index 4589c5f..c93ae28 100644
--- a/include/libfdt.h
+++ b/include/libfdt.h
@@ -1014,6 +1014,7 @@
/* Read-write functions */
/**********************************************************************/
+int fdt_create_empty_tree(void *buf, int bufsize);
int fdt_open_into(const void *fdt, void *buf, int bufsize);
int fdt_pack(void *fdt);