be6026838e
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>
84 lines
2.8 KiB
C
84 lines
2.8 KiB
C
/*
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* libfdt - Flat Device Tree manipulation
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* Copyright (C) 2012 David Gibson, IBM Corporation.
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*
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* libfdt is dual licensed: you can use it either under the terms of
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* the GPL, or the BSD license, at your option.
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*
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* a) This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this library; if not, write to the Free
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* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
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* MA 02110-1301 USA
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*
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* Alternatively,
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*
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* b) Redistribution and use in source and binary forms, with or
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* without modification, are permitted provided that the following
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* conditions are met:
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*
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* 1. Redistributions of source code must retain the above
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* copyright notice, this list of conditions and the following
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* disclaimer.
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* 2. Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "libfdt_env.h"
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#include <fdt.h>
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#include <libfdt.h>
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#include "libfdt_internal.h"
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int fdt_create_empty_tree(void *buf, int bufsize)
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{
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int err;
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err = fdt_create(buf, bufsize);
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if (err)
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return err;
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err = fdt_finish_reservemap(buf);
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if (err)
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return err;
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err = fdt_begin_node(buf, "");
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if (err)
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return err;
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err = fdt_end_node(buf);
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if (err)
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return err;
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err = fdt_finish(buf);
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if (err)
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return err;
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return fdt_open_into(buf, buf, bufsize);
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}
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