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authorGerald Van Baren <gvb@unssw.com>2012-10-15 22:24:36 -0400
committerGerald Van Baren <gvb@unssw.com>2012-10-15 22:24:36 -0400
commitc71b64f3617b5a4362c6e4e0aefdd66d6ac6affd (patch)
tree947b4febb1b863d9028274c064da2f698b803120
parent8ac88f2d2818c8efc1558626a4e7fb47dcc18987 (diff)
downloadu-boot-linaro-stable-c71b64f3617b5a4362c6e4e0aefdd66d6ac6affd.tar.gz
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>
-rw-r--r--include/libfdt.h1
-rw-r--r--lib/libfdt/Makefile2
-rw-r--r--lib/libfdt/fdt_empty_tree.c84
3 files changed, 86 insertions, 1 deletions
diff --git a/include/libfdt.h b/include/libfdt.h
index 4589c5feb..c93ae2883 100644
--- a/include/libfdt.h
+++ b/include/libfdt.h
@@ -1014,6 +1014,7 @@ int fdt_finish(void *fdt);
/* 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);
diff --git a/lib/libfdt/Makefile b/lib/libfdt/Makefile
index c965577dc..0693d4bf5 100644
--- a/lib/libfdt/Makefile
+++ b/lib/libfdt/Makefile
@@ -27,7 +27,7 @@ LIB = $(obj)libfdt.o
SOBJS =
-COBJS-libfdt += fdt.o fdt_ro.o fdt_rw.o fdt_strerror.o fdt_sw.o fdt_wip.o
+COBJS-libfdt += fdt.o fdt_ro.o fdt_rw.o fdt_strerror.o fdt_sw.o fdt_wip.o fdt_empty_tree.o
COBJS-$(CONFIG_OF_LIBFDT) += $(COBJS-libfdt)
COBJS-$(CONFIG_FIT) += $(COBJS-libfdt)
diff --git a/lib/libfdt/fdt_empty_tree.c b/lib/libfdt/fdt_empty_tree.c
new file mode 100644
index 000000000..f72d13b1d
--- /dev/null
+++ b/lib/libfdt/fdt_empty_tree.c
@@ -0,0 +1,84 @@
+/*
+ * 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);
+}
+