From: Frank Rowand <frank.rowand@xxxxxxxxxxxxxx> Create script to diff device trees. The device tree can be in any of the forms recognized by the dtc compiler: - source - binary blob - file system tree (from /proc/devicetree) If the device tree is a source file, then it is pre-processed in the same way as it would be when built in the linux kernel source tree before diffing. Signed-off-by: Frank Rowand <frank.rowand@xxxxxxxxxxxxxx> --- Tools to develop and debug device tree are somewhat inadequate. This is a small step in improving the situation. Rationale for and examples of using the script are provided in slides 1 - 78 of the elce 2015 presentation "Solving Device Tree Issues", which can be found at: http://elinux.org/images/0/04/Dt_debugging_elce_2015_151006_0421.pdf (The script was named dtdiff instead of dtx_diff in the presentation.) Changes in v2: - Remove dt-bindings from list of includes in cpp_flags - Remove arch_dtc_flags, which were generated from the arch specific dts makefile - Reformat to 8 character tabs - compile_to_dts(): added back missing return for binary blob scripts/dtc/dtx_diff | 343 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 343 insertions(+) Index: b/scripts/dtc/dtx_diff =================================================================== --- /dev/null +++ b/scripts/dtc/dtx_diff @@ -0,0 +1,343 @@ +#! /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}) does not match shell variable" >&2 + echo " \$ARCH (${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 ( ! 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: ${DTC} + + If it does not exist, create it from the root of the Linux source tree: + + 'make scripts'. + + If not at the root of the Linux kernel source tree -s SRCTREE or -S + may need to be specified to find 'dtc'. + + If 'O=\${dir}' is specified in your Linux builds, this script requires + 'export KBUILD_OUTPUT=\${dir}' or add \${dir}/scripts/dtc to \$PATH + before running. + + If \${KBUILD_OUTPUT} is a relative path, then '-s SRCDIR', -S, or run + this script from the root of the Linux kernel source tree is required. + + Fallback '${__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 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
