[uClinux-dev] Re: [PATCH 1/2] m68knommu: create config options for CPU classes

Geert Uytterhoeven geert at linux-m68k.org
Fri Jun 3 07:15:02 EDT 2011


On Fri, Jun 3, 2011 at 08:43,  <gerg at snapgear.com> wrote:
> From: Greg Ungerer <gerg at uclinux.org>
>
> There are 3 families of CPU core types that we support in the m68knommu
> architecture branch. They are
>
> . traditional 68000
> . CPU32 (which is a 68020 core derivitive without MMU)

derivative ... and without bitfield instructions.

> . ColdFire

> It will be useful going forward to have a CONFIG_ option defined for
> each type. We already have one for ColdFire (CONFIG_COLDFIRE), so add
> for the other 2 families, CONFIG_M68000 and CONFIG_MCPU32.

I'm wondering whether it would help to have Kconfig symbols for the
instruction capabilities as well.
Then you have to document these capabilities in the kconfig definition only,
and can use single (e.g.) #ifdef CONFIG_CPU_HAS_BITFIELDS tests everywhere
else, instead of duplicating the logic at every #ifdef.

> Signed-off-by: Greg Ungerer <gerg at uclinux.org>
> ---
>  arch/m68k/Kconfig.nommu |   52 ++++++++++++++++++++++++++++++++++++++++------
>  1 files changed, 45 insertions(+), 7 deletions(-)
>
> diff --git a/arch/m68k/Kconfig.nommu b/arch/m68k/Kconfig.nommu
> index fc98f9b..b004dc1 100644
> --- a/arch/m68k/Kconfig.nommu
> +++ b/arch/m68k/Kconfig.nommu
> @@ -14,6 +14,33 @@ config GENERIC_CLOCKEVENTS
>        bool
>        default n
>
> +config M68000
> +       bool
> +       help
> +         The Freescale (was Motorola) 68000 CPU is the first generation of
> +         the well known M68K family of processors. The CPU core as well as
> +         being available as a stand alone CPU was also used in many
> +         System-On-Chip devices (eg 68328, 68302, etc). It does not contain
> +         a paging MMU.
> +
> +config MCPU32
> +       bool
> +       help
> +         The Freescale (was then Motorola) CPU32 is a CPU core that is
> +         based on the 68020 processor. For the most part it is used in

without bitfield instructions.

> +         System-On-Chip parts, and does not contain a paging MMU.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds



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