Date:	Wed, 22 Aug 2012 11:24:34 -0400 (EDT)
From:	Nicolas Pitre <nicolas.pitre@...aro.org>
To:	Arnd Bergmann <arnd@...db.de>
cc:	linux-arm-kernel@...ts.infradead.org,
	linaro-kernel@...ts.linaro.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/4] [RFC] ARM: autogenerate mach-foo/* and plat-foo/*
 header redirects

On Wed, 22 Aug 2012, Arnd Bergmann wrote:

> This is an attempt to simplify the duplicate header problem for
> multiplatform kernels, in multiple steps:
> 
> 1. (this patch)
>    for each arch/arm/mach-${MACHINE}/include/mach-${MACHINE}/*.h file,
>    generate a arch/arm/include/generated/mach/*.h file at build time,
>    same for plat-*.
> 
> 2. rename all arch/arm/mach-${MACHINE}/include/mach/*.h to
>    arch/arm/mach-${MACHINE}/include/mach-${MACHINE}/*.h and
>    arch/arm/plat-${PLAT}/include/plat/*.h to
>    arch/arm/plat-${PLAT}/include/plat-${PLAT}/*.h
> 
> 3. change all includes of <mach/*.h> to <mach-${MACHINE}/*.h>
>    in all files where ${MACHINE} is known.
> 
> 4. ...
> 
> 5. Revert this patch again.
> 
> We can apply this patch at any time, and do step 2 at the end
> of the next merge window to minimize the potential for conflicts.
> We will also still need to deal with any inclusion of a mach/*
> file, but out of the 6355 ones we have today, I expect only a
> few hundred to remain after step 3 and they will be much easier
> to spot.
> 
> I've picked the format <mach-foo/bar.h> to get a unique name because
> it matches the directory name under arch/arm, but other names
> would work with the same script, <mach/foo-bar.h> and <foo/bar.h>
> have been suggested previously.
> 
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

Acked-by: Nicolas Pitre <nico@...aro.org>

> ---
>  arch/arm/Makefile          |    1 +
>  arch/arm/tools/Makefile    |    5 ++++
>  arch/arm/tools/gen-headers |   57 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 63 insertions(+)
>  create mode 100755 arch/arm/tools/gen-headers
> 
> diff --git a/arch/arm/Makefile b/arch/arm/Makefile
> index 30eae87..761b077 100644
> --- a/arch/arm/Makefile
> +++ b/arch/arm/Makefile
> @@ -274,6 +274,7 @@ boot := arch/arm/boot
>  
>  archprepare:
>         $(Q)$(MAKE) $(build)=arch/arm/tools include/generated/mach-types.h
> +       $(Q)$(MAKE) $(build)=arch/arm/tools plat="$(plat-y)" machine="$(machine-y)" gen_headers
>  
>  # Convert bzImage to zImage
>  bzImage: zImage
> diff --git a/arch/arm/tools/Makefile b/arch/arm/tools/Makefile
> index 635cb18..6e18ca9 100644
> --- a/arch/arm/tools/Makefile
> +++ b/arch/arm/tools/Makefile
> @@ -8,3 +8,8 @@ include/generated/mach-types.h: $(src)/gen-mach-types $(src)/mach-types
>         @echo '  Generating $@'
>         @mkdir -p $(dir $@)
>         $(Q)$(AWK) -f $^ > $@ || { rm -f $@; /bin/false; }
> +
> +gen_headers:
> +       $(Q)bash $(srctree)/$(src)/gen-headers $(srctree) $(objtree) $(machine) $(plat)
> +
> +.PHONY: gen_headers
> diff --git a/arch/arm/tools/gen-headers b/arch/arm/tools/gen-headers
> new file mode 100755
> index 0000000..caa6a9a
> --- /dev/null
> +++ b/arch/arm/tools/gen-headers
> @@ -0,0 +1,57 @@
> +#!/bin/bash
> +
> +SRC=$1
> +OBJ=$2
> +MACH=$3
> +PLAT1=$4
> +PLAT2=$5
> +
> +# create $3 to include $2 if it doesn't already have the correct
> +# contents, or remove it if it's no longer needed.
> +mkfile()
> +{
> +       if [ -e $1/$2 ] ; then
> +               if [ ! -e $3 ] ; then
> +                       mkdir -p ${3%/*}
> +                       echo "#include <${2}>" > $3
> +               elif [ "`cat $3`" != "#include <${2#./}>" ] ; then
> +                       echo "#include <${2}>" > $3
> +               fi
> +       elif [ ! -e $1/$2 -a -e $3 ] ; then
> +               rm -f $3
> +       fi
> +}
> +
> +# list any header files that are present in the source or
> +# destination directories
> +find_files()
> +{
> +       pushd ${SRC}/arch/arm/$1-$2/include/$1-$2 >/dev/null 2>&1 &&
> +       find . -type f -name \*.h -o -name \*.S &&
> +       popd > /dev/null 2>&1
> +       pushd ${OBJ}/arch/arm/include/generated/$1 >/dev/null 2>&1 &&
> +       find . -type f -name \*.h -o -name \*.S &&
> +       popd > /dev/null 2>&1
> +}
> +
> +# process files in either mach-{MACH} or plat-${PLAT}
> +mkfiles()
> +{
> +       mkdir -p ${OBJ}/arch/arm/include/generated/$1
> +
> +       FILES=`find_files $1 $2 | sort -u`
> +       for i in ${FILES} ; do
> +               mkfile "${SRC}/arch/arm/$1-$2/include/" "$1-$2/${i#./}" \
> +                       "${OBJ}/arch/arm/include/generated/$1/$i"
> +       done
> +}
> +
> +# always process mach-*
> +mkfiles mach ${MACH}
> +# process plat-* if applicable
> +if [ -d ${SRC}/arch/arm/plat-${PLAT1} ]; then
> +       mkfiles plat ${PLAT1}
> +fi
> +if [ -d ${SRC}/arch/arm/plat-${PLAT2} ]; then
> +       mkfiles plat ${PLAT2}
> +fi
> -- 
> 1.7.10
> 
> 
> _______________________________________________
> linaro-kernel mailing list
> linaro-kernel@...ts.linaro.org
> http://lists.linaro.org/mailman/listinfo/linaro-kernel
> 
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