Re: [PATCH RFC 2/2] m68k: setup_mm.c: set isa_sex for Atari if ATARI_ROM_ISA not used

Michael Schmitz
2021-06-04T03:04:01Z

Hi Finn,

Am 03.06.2021 um 20:29 schrieb Finn Thain:
>>> However, this is inside the CONFIG_ISA && MULTI_ISA block, so what
>>> kind of ISA does this correspond to?
>>
>> No ISA at all in that case, but since we have to route all readw() calls
>> through isa_readw() for the sake of generality if we want to support Q40
>> ISA and Atari MMIO in the same kernel image, we need to make sure
>> isa_readw() does the right thing on Atari if CONFIG_ISA is set.
>>
>> I know io_mm.h says it's about various ISA bridges, but as I found out,
>> drivers using only MMIO are also affected by these definitions.
>>
>> 'Maze' does not begin to describe it, 'mess' might be getting closer,
>> but I can't see how we would avoid use of definitions in io_mm.h by
>> non-ISA drivers.
>>
>
> It seems that the need for explicit zero initialization has more to do
> with subtelty over in asm/io_mm.h than anything else. If so, it would be
> better to add commentary there than to add redundant code here.

OK, I'll drop this one and rely on default zero initialization of
globals instead.

More explicit setting of MULTI_ISA along with comments will be included
in v2 of the remaining patch.

Thanks!

Michael