Re: Old platforms: bring out your dead

On 11/1/21 7:36 pm, Geert Uytterhoeven wrote:

Hi Adrian,

On Mon, Jan 11, 2021 at 10:26 AM John Paul Adrian Glaubitz
[off-list ref] wrote:

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On 1/11/21 10:20 AM, Geert Uytterhoeven wrote:

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Sounds interesting. Do these SoCs come with an MMU? And do they use the
ColdFire instruction set or do they run plain 68k code?

No MMU, plain m68k code.

68328 Soc = 68000 core + some peripherals,
68360 SoC = CPU32 core (based on 68020 + some peripherals.

OK, I guess that would be useful for the NoMMU Linux port.

Note that 68360 support was removed from the kernel in 2016, as
Arnd said.

And that 68360 was bit rotten for a very long time before that.
Nobody ever seemed to show much interest in it.

Keep in mind that the 68328 family of parts are pretty slow too...

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Anyone working on integrating m68k (and SPARC and MIPS?) softcores in
LiteX? ;-)

I'm personally waiting for the Vampire to gain support for the real 68851
as the hardware in general looks very attractive [1].

The 68851 is way too complex for what's needed (who needs support for
256 byte pages (https://lwn.net/Articles/839746/)?).
They'd be better off implementing something simpler, like 68040 MMU
support, or perhaps even a software-controlled TLB like most RISC
architectures (incl. ColdFire?).  The latter would require more changes
to Linux, though.

Yep, the ColdFire MMU is a software controlled TLB.

Regards
Greg