Re: [PATCH] kbuild: remove unneeded -O option to dtc
From: Viresh Kumar <viresh.kumar@linaro.org>
Date: 2021-03-10 14:42:29
Also in:
linux-kbuild, lkml
On 10-03-21, 20:08, Masahiro Yamada wrote:
This piece of code converts the target suffix to the dtc -O option:
*.dtb -> -O dtb
*.dt.yaml -> -O yaml
Commit ce88c9c79455 ("kbuild: Add support to build overlays (%.dtbo)")
added the third case:
*.dtbo -> -O dtbo
This works thanks to commit 163f0469bf2e ("dtc: Allow overlays to have
.dtbo extension") in the upstream DTC, which has already been pulled in
the kernel.
However, I think it is a bit odd because "dtbo" is not a format name.
At least, it does not show up in the help message of dtc.
$ scripts/dtc/dtc --help
[ snip ]
-O, --out-format <arg>
Output formats are:
dts - device tree source text
dtb - device tree blob
yaml - device tree encoded as YAML
asm - assembler source
So, I am not a big fan of the second hunk of that change:
} else if (streq(outform, "dtbo")) {
dt_to_blob(outf, dti, outversion);Looking at the very first version of the patch I sent, https://lore.kernel.org/lkml/7aa70809eff3f32d821761d2a763e4fb72ecc8fb.1609844956.git.viresh.kumar@linaro.org/ (local) this change was the only thing that was required to make it work. I think the reason was that "outform != NULL" as -O option was passed by the kernel.
quoted hunk ↗ jump to hunk
Anyway, we did not need to do this in Makefile in the first place. guess_type_by_name() had already understood ".yaml" before commit 4f0e3a57d6eb ("kbuild: Add support for DT binding schema checks"), and now does ".dtbo" as well. Makefile does not need to duplicate the same logic. Let's leave it to dtc. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- scripts/Makefile.lib | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index eee59184de64..90a4e04cd8f5 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib@@ -327,7 +327,7 @@ $(obj)/%.dtb.S: $(obj)/%.dtb FORCE quiet_cmd_dtc = DTC $@ cmd_dtc = $(HOSTCC) -E $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ; \ - $(DTC) -O $(patsubst .%,%,$(suffix $@)) -o $@ -b 0 \ + $(DTC) -o $@ -b 0 \ $(addprefix -i,$(dir $<) $(DTC_INCLUDE)) $(DTC_FLAGS) \ -d $(depfile).dtc.tmp $(dtc-tmp) ; \ cat $(depfile).pre.tmp $(depfile).dtc.tmp > $(depfile)
LGTM. Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org> -- viresh