[PATCH 2/3] m68k: Add support for M68040 CPU

Tom Rini trini at konsulko.com
Thu Dec 18 20:00:32 CET 2025


On Thu, Dec 18, 2025 at 06:52:51PM +0000, Kuan-Wei Chiu wrote:
> Add support for the Motorola 68040 architecture. Currently, m68k
> support in U-Boot is primarily focused on ColdFire (MCF5xxx) variants.
> Introduce the necessary infrastructure to support the classic M680x0
> series, specifically targeting the M68040 as emulated by QEMU.
> 
> The implementation includes exception vectors, early startup code, and
> minimal CPU initialization and relocation stubs. It also defines the
> standard m68k boot information structure used for passing hardware
> information to the operating system. To ensure compatibility, ColdFire-
> specific library objects such as cache and interrupt handling are
> excluded from the build when M68040 is selected.
> 
> Additionally, apply a specific workaround during the early memory
> reservation stage. Use a manual loop to clear global data instead of
> the standard memset() function, as utilizing memset() at this point was
> observed to cause a hang on the QEMU platform.
> 
> Signed-off-by: Kuan-Wei Chiu <visitorckw at gmail.com>
[snip]
> diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
> index 8ade6f7b9d1..a41c375f6be 100644
> --- a/arch/m68k/Kconfig
> +++ b/arch/m68k/Kconfig
> @@ -56,6 +56,9 @@ config MCF5441x
>          select DM_SERIAL
>  	bool
>  
> +config M68040
> +    bool
> +

The file is unfortunately inconsistent about tabs vs spaces, but all the
new options should be tab-indent only, and no extra blank lines added.

-- 
Tom
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