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Subject: Re: Old platforms: bring out your dead
To:     Geert Uytterhoeven <geert@linux-m68k.org>,
        John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
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From:   Greg Ungerer <gerg@linux-m68k.org>
Message-ID: <9e9cc4ad-38b0-f799-cd0e-c1e1c7e3501c@linux-m68k.org>
Date:   Mon, 11 Jan 2021 19:50:07 +1000
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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
> <glaubitz@physik.fu-berlin.de> wrote:
>> On 1/11/21 10:20 AM, Geert Uytterhoeven wrote:
>>>> 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...


>>> 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