1#! /bin/bash
2# SPDX-License-Identifier: GPL-2.0-only
3
4# Copyright (C) 2015 Frank Rowand
5#
6
7
8usage() {
9
10	# use spaces instead of tabs in the usage message
11	cat >&2 <<eod
12
13Usage:
14
15   `basename $0` DTx
16        decompile DTx
17
18   `basename $0` DTx_1 DTx_2
19        diff DTx_1 and DTx_2
20
21
22      --annotate    synonym for -T
23      --color       synonym for -c (requires diff with --color support)
24       -c           enable colored output
25       -f           print full dts in diff (--unified=99999)
26       -h           synonym for --help
27       -help        synonym for --help
28      --help        print this message and exit
29       -s SRCTREE   linux kernel source tree is at path SRCTREE
30                        (default is current directory)
31       -S           linux kernel source tree is at root of current git repo
32       -T           annotate output .dts with input source file and line
33                        (-T -T for more details)
34       -u           unsorted, do not sort DTx
35
36
37Each DTx is processed by the dtc compiler to produce a sorted dts source
38file.  If DTx is a dts source file then it is pre-processed in the same
39manner as done for the compile of the dts source file in the Linux kernel
40build system ('#include' and '/include/' directives are processed).
41
42If two DTx are provided, the resulting dts source files are diffed.
43
44If DTx is a directory, it is treated as a DT subtree, such as
45  /proc/device-tree.
46
47If DTx contains the binary blob magic value in the first four bytes,
48  it is treated as a binary blob (aka .dtb or FDT).
49
50Otherwise DTx is treated as a dts source file (aka .dts).
51
52   If this script is not run from the root of the linux source tree,
53   and DTx utilizes '#include' or '/include/' then the path of the
54   linux source tree can be provided by '-s SRCTREE' or '-S' so that
55   include paths will be set properly.
56
57   The shell variable \${ARCH} must provide the architecture containing
58   the dts source file for include paths to be set properly for '#include'
59   or '/include/' to be processed.
60
61   If DTx_1 and DTx_2 are in different architectures, then this script
62   may not work since \${ARCH} is part of the include path.  Two possible
63   workarounds:
64
65      `basename $0` \\
66          <(ARCH=arch_of_dtx_1 `basename $0` DTx_1) \\
67          <(ARCH=arch_of_dtx_2 `basename $0` DTx_2)
68
69      `basename $0` ARCH=arch_of_dtx_1 DTx_1 >tmp_dtx_1.dts
70      `basename $0` ARCH=arch_of_dtx_2 DTx_2 >tmp_dtx_2.dts
71      `basename $0` tmp_dtx_1.dts tmp_dtx_2.dts
72      rm tmp_dtx_1.dts tmp_dtx_2.dts
73
74   If DTx_1 and DTx_2 are in different directories, then this script will
75   add the path of DTx_1 and DTx_2 to the include paths.  If DTx_2 includes
76   a local file that exists in both the path of DTx_1 and DTx_2 then the
77   file in the path of DTx_1 will incorrectly be included.  Possible
78   workaround:
79
80      `basename $0` DTx_1 >tmp_dtx_1.dts
81      `basename $0` DTx_2 >tmp_dtx_2.dts
82      `basename $0` tmp_dtx_1.dts tmp_dtx_2.dts
83      rm tmp_dtx_1.dts tmp_dtx_2.dts
84
85eod
86}
87
88
89compile_to_dts() {
90
91	dtx="$1"
92	dtc_include="$2"
93
94	if [ -d "${dtx}" ] ; then
95
96		# -----  input is file tree
97
98		if ( ! ${DTC} -I fs ${dtx} ) ; then
99			exit 3
100		fi
101
102	elif [ -f "${dtx}" ] && [ -r "${dtx}" ] ; then
103
104		magic=`hexdump -n 4 -e '/1 "%02x"' ${dtx}`
105		if [ "${magic}" = "d00dfeed" ] ; then
106
107			# -----  input is FDT (binary blob)
108
109			if ( ! ${DTC} -I dtb ${dtx} ) ; then
110				exit 3
111			fi
112
113			return
114
115		fi
116
117		# -----  input is DTS (source)
118
119		if ( cpp ${cpp_flags} -x assembler-with-cpp ${dtx} \
120			| ${DTC} ${dtc_include} -I dts ) ; then
121			return
122		fi
123
124		echo ""                                                      >&2
125		echo "Possible hints to resolve the above error:"            >&2
126		echo "  (hints might not fix the problem)"                   >&2
127
128		hint_given=0
129
130		if [ "${ARCH}" = "" ] ; then
131			hint_given=1
132			echo ""                                              >&2
133			echo "  shell variable \$ARCH not set"               >&2
134		fi
135
136		dtx_arch=`echo "/${dtx}" | sed -e 's|.*/arch/||' -e 's|/.*||'`
137
138		if [ "${dtx_arch}" != ""  -a "${dtx_arch}" != "${ARCH}" ] ; then
139			hint_given=1
140			echo ""                                              >&2
141			echo "  architecture ${dtx_arch} is in file path,"   >&2
142			echo "  but does not match shell variable \$ARCH"    >&2
143			echo "  >>\$ARCH<< is: >>${ARCH}<<"                  >&2
144		fi
145
146		if [ ! -d ${srctree}/arch/${ARCH} ] ; then
147			hint_given=1
148			echo ""                                              >&2
149			echo "  ${srctree}/arch/${ARCH}/ does not exist"     >&2
150			echo "  Is \$ARCH='${ARCH}' correct?"                >&2
151			echo "  Possible fix: use '-s' option"               >&2
152
153			git_root=`git rev-parse --show-toplevel 2>/dev/null`
154			if [ -d ${git_root}/arch/ ] ; then
155				echo "  Possible fix: use '-S' option"       >&2
156			fi
157		fi
158
159		if [ $hint_given = 0 ] ; then
160			echo ""                                              >&2
161			echo "  No hints available."                         >&2
162		fi
163
164		echo ""                                                      >&2
165
166		exit 3
167
168	else
169		echo ""                                                     >&2
170		echo "ERROR: ${dtx} does not exist or is not readable"      >&2
171		echo ""                                                     >&2
172		exit 2
173	fi
174
175}
176
177
178# -----  start of script
179
180annotate=""
181cmd_diff=0
182diff_flags="-u"
183diff_color=""
184dtx_file_1=""
185dtx_file_2=""
186dtc_sort="-s"
187help=0
188srctree=""
189
190
191while [ $# -gt 0 ] ; do
192
193	case $1 in
194
195	-c | --color )
196		if diff --color /dev/null /dev/null 2>/dev/null ; then
197			diff_color="--color=always"
198		fi
199		shift
200		;;
201
202	-f )
203		diff_flags="--unified=999999"
204		shift
205		;;
206
207	-h | -help | --help )
208		help=1
209		shift
210		;;
211
212	-s )
213		srctree="$2"
214		shift 2
215		;;
216
217	-S )
218		git_root=`git rev-parse --show-toplevel 2>/dev/null`
219		srctree="${git_root}"
220		shift
221		;;
222
223	-T | --annotate )
224		if [ "${annotate}"  = "" ] ; then
225			annotate="-T"
226		elif [ "${annotate}"  = "-T" ] ; then
227			annotate="-T -T"
228		fi
229		shift
230		;;
231	-u )
232		dtc_sort=""
233		shift
234		;;
235
236	*)
237		if [ "${dtx_file_1}"  = "" ] ; then
238			dtx_file_1="$1"
239		elif [ "${dtx_file_2}" = "" ] ; then
240			dtx_file_2="$1"
241		else
242			echo ""                                             >&2
243			echo "ERROR: Unexpected parameter: $1"              >&2
244			echo ""                                             >&2
245			exit 2
246		fi
247		shift
248		;;
249
250	esac
251
252done
253
254if [ "${srctree}" = "" ] ; then
255	srctree="."
256fi
257
258if [ "${dtx_file_2}" != "" ]; then
259	cmd_diff=1
260fi
261
262if (( ${help} )) ; then
263	usage
264	exit 1
265fi
266
267# this must follow check for ${help}
268if [ "${dtx_file_1}" = "" ]; then
269	echo ""                                                             >&2
270	echo "ERROR: parameter DTx required"                                >&2
271	echo ""                                                             >&2
272	exit 2
273fi
274
275
276# -----  prefer dtc from linux kernel, allow fallback to dtc in $PATH
277
278if [ "${KBUILD_OUTPUT:0:2}" = ".." ] ; then
279	__KBUILD_OUTPUT="${srctree}/${KBUILD_OUTPUT}"
280elif [ "${KBUILD_OUTPUT}" = "" ] ; then
281	__KBUILD_OUTPUT="."
282else
283	__KBUILD_OUTPUT="${KBUILD_OUTPUT}"
284fi
285
286DTC="${__KBUILD_OUTPUT}/scripts/dtc/dtc"
287
288if [ ! -x ${DTC} ] ; then
289	__DTC="dtc"
290	if grep -q "^CONFIG_DTC=y" ${__KBUILD_OUTPUT}/.config 2>/dev/null; then
291		make_command='
292         make scripts'
293	else
294		make_command='
295         Enable CONFIG_DTC in the kernel configuration
296         make scripts'
297	fi
298	if ( ! which ${__DTC} >/dev/null ) ; then
299
300		# use spaces instead of tabs in the error message
301		cat >&2 <<eod
302
303ERROR: unable to find a 'dtc' program
304
305   Preferred 'dtc' (built from Linux kernel source tree) was not found or
306   is not executable.
307
308      'dtc' is: ${DTC}
309
310      If it does not exist, create it from the root of the Linux source tree:
311${make_command}
312
313      If not at the root of the Linux kernel source tree -s SRCTREE or -S
314      may need to be specified to find 'dtc'.
315
316      If 'O=\${dir}' is specified in your Linux builds, this script requires
317      'export KBUILD_OUTPUT=\${dir}' or add \${dir}/scripts/dtc to \$PATH
318      before running.
319
320      If \${KBUILD_OUTPUT} is a relative path, then '-s SRCDIR', -S, or run
321      this script from the root of the Linux kernel source tree is required.
322
323   Fallback '${__DTC}' was also not in \${PATH} or is not executable.
324
325eod
326		exit 2
327	fi
328	DTC=${__DTC}
329fi
330
331
332# -----  cpp and dtc flags same as for linux source tree build of .dtb files,
333#        plus directories of the dtx file(s)
334
335dtx_path_1_dtc_include="-i `dirname ${dtx_file_1}`"
336
337dtx_path_2_dtc_include=""
338if (( ${cmd_diff} )) ; then
339	dtx_path_2_dtc_include="-i `dirname ${dtx_file_2}`"
340fi
341
342cpp_flags="\
343	-nostdinc                                  \
344	-I${srctree}/scripts/dtc/include-prefixes  \
345	-undef -D__DTS__"
346
347DTC="\
348	${DTC}                                     \
349	-i ${srctree}/scripts/dtc/include-prefixes \
350	-O dts -qq -f ${dtc_sort} ${annotate} -o -"
351
352
353# -----  do the diff or decompile
354
355if (( ${cmd_diff} )) ; then
356
357	diff ${diff_flags} ${diff_color} --label "${dtx_file_1}" --label "${dtx_file_2}" \
358		<(compile_to_dts "${dtx_file_1}" "${dtx_path_1_dtc_include}") \
359		<(compile_to_dts "${dtx_file_2}" "${dtx_path_2_dtc_include}")
360
361else
362
363	compile_to_dts "${dtx_file_1}" "${dtx_path_1_dtc_include}"
364
365fi
366