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Re: [RFC PATCH] MIPS: move out Alchemy stuff to separate Makefile

To: Manuel Lauss <>
Subject: Re: [RFC PATCH] MIPS: move out Alchemy stuff to separate Makefile
From: Ralf Baechle <>
Date: Fri, 24 Apr 2009 08:00:15 +0200
Cc: Linux-MIPS <>, Sam Ravnborg <>
In-reply-to: <>
Original-recipient: rfc822;
References: <>
User-agent: Mutt/1.5.18 (2008-05-17)
On Fri, Apr 24, 2009 at 07:41:28AM +0200, Manuel Lauss wrote:

> Move Makefile information on all Alchemy boards to a separate file
> in the arch subdir.
> Signed-off-by: Manuel Lauss <>
> ---
> Applies on top of my Alchemy-gpio patches;  builds and runs fine on a few
> different alchemy systems.  It seems nicer to not have to modify the main
> mips makefile when adding new alchemy boards. What do you all think?
>  arch/mips/Makefile         |  104 +------------------------------------------
>  arch/mips/alchemy/Makefile |  106 
> ++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 108 insertions(+), 102 deletions(-)
>  create mode 100644 arch/mips/alchemy/Makefile

I think Sam Ravnbord has written something like the grand plan for the
cleanup a few days ago; I append his mail below.


Date:   Tue, 21 Apr 2009 21:43:43 +0200
From:   Sam Ravnborg <>
To:     Ralf Baechle <>
Subject: Re: introduce arch/$ARCH/Kbuild ?
Message-ID: <>
References: <> 
In-Reply-To: <>

> Most of arch/mips uses -Werror these days and while painful at times it
> keeps everybody on their toes hopefully cleaner, less buggy code.  So if
> your solution allows adding -Werror to all subdirs automatically with
> a mechanism to remove -Werror from a few selected dirs then I'm interested.

It is already present in mainline - so go wild.

I took a look at mips.
mips supports an impressive amount of platform/boards.
The has resulted in lines like the following in the arch Makefile:

core-$(CONFIG_SGI_IP32)         += arch/mips/sgi-ip32/
cflags-$(CONFIG_SGI_IP32)       += -I$(srctree)/arch/mips/include/asm/mach-ip32
load-$(CONFIG_SGI_IP32)         += 0xffffffff80004000

But this is less then optimal. If two people add a paltform you will
have a merge issue.
And centralize information like that is also questionable.

mips would be better suited if you had all sgi_ip32 information located
in a single directory.

How about a setup like this:

platfrom-y                      += arch/mips/sgi-ip32/
cflags-$(CONFIG_SGI_IP32)       += -I$(srctree)/arch/mips/include/asm/mach-ip32
load-$(CONFIG_SGI_IP32)         += 0xffffffff80004000

#All platforms listed in alphabetic order
platforms-y += lasat/
platforms-y += sgi_ip32/

#include the platform specific files
include $(patsubst %, arch/misp/%Platform)

subdir-ccflags-y := -Werror

include arch/mips/Kbuild.platforms
obj-y += $(platform-y)

obj-y +=  arch/mips/kernel/ arch/mips/mm/ arch/mips/math-emu/

core-y += arch/mips/
include arch/mips/Kbuild.platforms

The above does a few things:
1) It decentralize the plaform stuff (to the Platform files)
2) In troduces a arch/mips/Kbuild file that specify everything
   that is linked in as core-y
3) It adds a single subdir-ccflags-y := -Werror that covers
   all platforms and the core part of the kernel
   (Everything specified in arch/mips/Kbuild)
4) It reuses Kbuild.platforms in Kbuild and
   in Makefile.
   In Makefile it is used to find ccflags-y
   and load-y definitions.
   In Kbuild it is used to find the objects to add to obj-y.

The above is entirely untested - but I hope to have adressed the principles.


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