#! /bin/bash
# Copyright (C) 2015 Frank Rowand
#
# This program 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; version 2 of the License.
usage() {
# use spaces instead of tabs in the usage message
cat >&2 <<eod
Usage:
`basename $0` DTx
decompile DTx
`basename $0` DTx_1 DTx_2
diff DTx_1 and DTx_2
-f print full dts in diff (--unified=99999)
-h synonym for --help
-help synonym for --help
--help print this message and exit
-s SRCTREE linux kernel source tree is at path SRCTREE
(default is current directory)
-S linux kernel source tree is at root of current git repo
-u unsorted, do not sort DTx
Each DTx is processed by the dtc compiler to produce a sorted dts source
file. If DTx is a dts source file then it is pre-processed in the same
manner as done for the compile of the dts source file in the Linux kernel
build system ('#include' and '/include/' directives are processed).
If two DTx are provided, the resulting dts source files are diffed.
If DTx is a directory, it is treated as a DT subtree, such as
/proc/device-tree.
If DTx contains the binary blob magic value in the first four bytes,
it is treated as a binary blob (aka .dtb or FDT).
Otherwise DTx is treated as a dts source file (aka .dts).
If this script is not run from the root of the linux source tree,
and DTx utilizes '#include' or '/include/' then the path of the
linux source tree can be provided by '-s SRCTREE' or '-S' so that
include paths will be set properly.
The shell variable \${ARCH} must provide the architecture containing
the dts source file for include paths to be set properly for '#include'
or '/include/' to be processed.
If DTx_1 and DTx_2 are in different architectures, then this script
may not work since \${ARCH} is part of the include path. Two possible
workarounds:
`basename $0` \\
<(ARCH=arch_of_dtx_1 `basename $0` DTx_1) \\
<(ARCH=arch_of_dtx_2 `basename $0` DTx_2)
`basename $0` ARCH=arch_of_dtx_1 DTx_1 >tmp_dtx_1.dts
`basename $0` ARCH=arch_of_dtx_2 DTx_2 >tmp_dtx_2.dts
`basename $0` tmp_dtx_1.dts tmp_dtx_2.dts
rm tmp_dtx_1.dts tmp_dtx_2.dts
If DTx_1 and DTx_2 are in different directories, then this script will
add the path of DTx_1 and DTx_2 to the include paths. If DTx_2 includes
a local file that exists in both the path of DTx_1 and DTx_2 then the
file in the path of DTx_1 will incorrectly be included. Possible
workaround:
`basename $0` DTx_1 >tmp_dtx_1.dts
`basename $0` DTx_2 >tmp_dtx_2.dts
`basename $0` tmp_dtx_1.dts tmp_dtx_2.dts
rm tmp_dtx_1.dts tmp_dtx_2.dts
eod
}
compile_to_dts() {
dtx="$1"
if [ -d "${dtx}" ] ; then
# ----- input is file tree
if ( ! ${DTC} -I fs ${dtx} ) ; then
exit 3
fi
elif [ -f "${dtx}" ] && [ -r "${dtx}" ] ; then
magic=`hexdump -n 4 -e '/1 "%02x"' ${dtx}`
if [ "${magic}" = "d00dfeed" ] ; then
# ----- input is FDT (binary blob)
if ( ! ${DTC} -I dtb ${dtx} ) ; then
exit 3
fi
return
fi
# ----- input is DTS (source)
if ( cpp ${cpp_flags} -x assembler-with-cpp ${dtx} \
| ${DTC} -I dts ) ; then
return
fi
echo "" >&2
echo "Possible hints to resolve the above error:" >&2
echo " (hints might not fix the problem)" >&2
hint_given=0
if [ "${ARCH}" = "" ] ; then
hint_given=1
echo "" >&2
echo " shell variable \$ARCH not set" >&2
fi
dtx_arch=`echo "/${dtx}" | sed -e 's|.*/arch/||' -e 's|/.*||'`
if [ "${dtx_arch}" != "" -a "${dtx_arch}" != "${ARCH}" ] ; then
hint_given=1
echo "" >&2
echo " architecture ${dtx_arch} is in file path," >&2
echo " but does not match shell variable \$ARCH" >&2
echo " >>\$ARCH<< is: >>${ARCH}<<" >&2
fi
if [ ! -d ${srctree}/arch/${ARCH} ] ; then
hint_given=1
echo "" >&2
echo " ${srctree}/arch/${ARCH}/ does not exist" >&2
echo " Is \$ARCH='${ARCH}' correct?" >&2
echo " Possible fix: use '-s' option" >&2
git_root=`git rev-parse --show-toplevel 2>/dev/null`
if [ -d ${git_root}/arch/ ] ; then
echo " Possible fix: use '-S' option" >&2
fi
fi
if [ $hint_given = 0 ] ; then
echo "" >&2
echo " No hints available." >&2
fi
echo "" >&2
exit 3
else
echo "" >&2
echo "ERROR: ${dtx} does not exist or is not readable" >&2
echo "" >&2
exit 2
fi
}
# ----- start of script
cmd_diff=0
diff_flags="-u"
dtx_file_1=""
dtx_file_2=""
dtc_sort="-s"
help=0
srctree=""
while [ $# -gt 0 ] ; do
case $1 in
-f )
diff_flags="--unified=999999"
shift
;;
-h | -help | --help )
help=1
shift
;;
-s )
srctree="$2"
shift 2
;;
-S )
git_root=`git rev-parse --show-toplevel 2>/dev/null`
srctree="${git_root}"
shift
;;
-u )
dtc_sort=""
shift
;;
*)
if [ "${dtx_file_1}" = "" ] ; then
dtx_file_1="$1"
elif [ "${dtx_file_2}" = "" ] ; then
dtx_file_2="$1"
else
echo "" >&2
echo "ERROR: Unexpected parameter: $1" >&2
echo "" >&2
exit 2
fi
shift
;;
esac
done
if [ "${srctree}" = "" ] ; then
srctree="."
fi
if [ "${dtx_file_2}" != "" ]; then
cmd_diff=1
fi
if (( ${help} )) ; then
usage
exit 1
fi
# this must follow check for ${help}
if [ "${dtx_file_1}" = "" ]; then
echo "" >&2
echo "ERROR: parameter DTx required" >&2
echo "" >&2
exit 2
fi
# ----- prefer dtc from linux kernel, allow fallback to dtc in $PATH
if [ "${KBUILD_OUTPUT:0:2}" = ".." ] ; then
__KBUILD_OUTPUT="${srctree}/${KBUILD_OUTPUT}"
elif [ "${KBUILD_OUTPUT}" = "" ] ; then
__KBUILD_OUTPUT="."
else
__KBUILD_OUTPUT="${KBUILD_OUTPUT}"
fi
DTC="${__KBUILD_OUTPUT}/scripts/dtc/dtc"
if [ ! -x ${DTC} ] ; then
__DTC="dtc"
if grep -q "^CONFIG_DTC=y" ${__KBUILD_OUTPUT}/.config 2>/dev/null; then
make_command='
make scripts'
else
make_command='
Enable CONFIG_DTC in the kernel configuration
make scripts'
fi
if ( ! which ${__DTC} >/dev/null ) ; then
# use spaces instead of tabs in the error message
cat >&2 <<eod
ERROR: unable to find a 'dtc' program
Preferred 'dtc' (built from Linux kernel source tree) was not found or
is not executable.
'dtc' is: ${DTC}
If it does not exist, create it from the root of the Linux source tree:
${make_command}
If not at the root of the Linux kernel source tree -s SRCTREE or -S
may need to be specified to find 'dtc'.
If 'O=\${dir}' is specified in your Linux builds, this script requires
'export KBUILD_OUTPUT=\${dir}' or add \${dir}/scripts/dtc to \$PATH
before running.
If \${KBUILD_OUTPUT} is a relative path, then '-s SRCDIR', -S, or run
this script from the root of the Linux kernel source tree is required.
Fallback '${__DTC}' was also not in \${PATH} or is not executable.
eod
exit 2
fi
DTC=${__DTC}
fi
# ----- cpp and dtc flags same as for linux source tree build of .dtb files,
# plus directories of the dtx file(s)
dtx_path_1_dtc_include="-i `dirname ${dtx_file_1}`"
dtx_path_2_dtc_include=""
if (( ${cmd_diff} )) ; then
dtx_path_2_dtc_include="-i `dirname ${dtx_file_2}`"
fi
cpp_flags="\
-nostdinc \
-I${srctree}/arch/${ARCH}/boot/dts \
-I${srctree}/arch/${ARCH}/boot/dts/include \
-I${srctree}/drivers/of/testcase-data \
-undef -D__DTS__"
dtc_flags="\
-i ${srctree}/arch/${ARCH}/boot/dts/ \
-i ${srctree}/kernel/dts \
${dtx_path_1_dtc_include} \
${dtx_path_2_dtc_include}"
DTC="${DTC} ${dtc_flags} -O dts -qq -f ${dtc_sort} -o -"
# ----- do the diff or decompile
if (( ${cmd_diff} )) ; then
diff ${diff_flags} \
<(compile_to_dts "${dtx_file_1}") \
<(compile_to_dts "${dtx_file_2}")
else
compile_to_dts "${dtx_file_1}"
fi