[OpenWrt-Devel] [PATCH v2] Add support for C-style in dtsi files

[Jonas Gorski]

Hi,

On Fri, Dec 4, 2015 at 12:40 AM, Nikolay Martynov <mar.kolya at gmail.com> wrote:
> Current way of compuling dts files involves calling C preprocessor on
> main dts file only. This means that dtsi includes cannot have C-style includes.

Why not? Shouldn't they get processed as well as long as they are
included with #include, not /include/? Can you give an example that
doesn't work?

> This patch addresses this problem. It uses approach similar to one
> use in linux kernel: it preprocesses all dtsi's in current dir into
> tmp dir and then uses that tmp dir as include dir for main dts compilation.

I can't find this code in the kernel at all. Can you please point that out?

> Note: this patch preprocesses onlt *.dtsi, not *.dts, so only *.dtsi
> can be includes, but it looks like all current architectures follow this convention.
>
> This approach should be compatible with all current architectures.
>
> This patch also updates ramips arch to use new dtsi comilation code.
>
> v2: Use LINUX_KARCH to get to linux dh bindings.

This issue was copied from the DTS_DIR decleration, so maybe you can
fix that one up and then use -I$(DTS_DIR) -I$(DTS_DIR)/include ?

>
> Signed-off-by: Nikolay Martynov <mar.kolya at gmail.com>
> ---
>  include/image.mk                   | 24 ++++++++++++++++++------
>  target/linux/ramips/image/Makefile |  2 +-
>  2 files changed, 19 insertions(+), 7 deletions(-)
>
> diff --git a/include/image.mk b/include/image.mk
> index fd5e3f4..fa0314f 100644
> --- a/include/image.mk
> +++ b/include/image.mk
> @@ -138,19 +138,31 @@ define Image/BuildKernel/MkFIT
>  endef
>
>  # $(1) source dts file
> +# $(2) target dts file
> +# $(3) extra CPP flags
> +define Image/PreprocessDTS
> +       $(CPP) -nostdinc -x assembler-with-cpp \
> +               -I$(LINUX_DIR)/arch/$(LINUX_KARCH)/boot/dts \
> +               -I$(LINUX_DIR)/arch/$(LINUX_KARCH)/boot/dts/include \
> +               -undef -D__DTS__ $(3) \
> +               -o $(2) $(1);
> +endef
> +
> +
> +# $(1) source dts file
>  # $(2) target dtb file
>  # $(3) extra CPP flags
>  # $(4) extra DTC flags
>  define Image/BuildDTB
> -       $(CPP) -nostdinc -x assembler-with-cpp \
> -               -I$(LINUX_DIR)/arch/$(ARCH)/boot/dts \
> -               -I$(LINUX_DIR)/arch/$(ARCH)/boot/dts/include \
> -               -undef -D__DTS__ $(3) \
> -               -o $(2).tmp $(1)
> +       mkdir -p $(2).inc.tmp
> +       $(foreach inc,$(wildcard $(dir $(1))*.dtsi), \
> +               $(call Image/PreprocessDTS,$(inc),$(2).inc.tmp/$(notdir $(inc)),$(3)))

If I read this right you preprocess all dtsi files found there every
time you want to compile a dts file. This sounds like a lot of
unnecessary processing on e.g. arm, where arch/arm/boot/dts contains
435 .dtsi files as of 4.1. And since you remove the preprocessed
files, you need to do it again for the next dts file.


Jonas
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