Re: [PATCH 1/1] Changes for 68000 code integration.

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Hi all,

Thanks for the comments, answering below:


Greg:
The CONFIG_CPU32 designator is not correct for 68x328 parts, they
do not have a CPU32 core. They are standard 68000 cores internally.

That's true! I thought they had a CPU32 core like the 68360 and all 683xx parts.
(And even if they had, the config would be wrong since CPU32 supports divul)


Although there was no true 68000 part supported before the intention
of the CONFIG_M68000 define was for that CPU - or any SoC type part that
contained a true 68000 CPU core. And it would be good to keep that
naming so it is consistent with the other 680x0 cores.

It makes a lot more sense now. I'll change the files and submit a new patch.



Geert:
But the actual arch/m68k/platform/68000/ part is missing?

Yes, I'll send it in the next patch. I already have a fully working kernel
for my board, but since the 68000 doesn't have any on-chip peripherals the
config will be a lot 'board-dependent' I'm figuring out a way to
organize the files.
I could use some suggestions in here.
Should I use:
1) Single common files with "#ifdef CONFIG_<board>" conditionals
2) Common config in arch/m68k/platform/68000/ and board specific
   config in arch/m68k/platform/68000/<boardname>/
3) Other suggestion...

At the moment I'm using option 1) since I suspect there won't be many
boards using
the old 68000 (although I already have some guys asking for code).

"CONFIG_M68XXX || CONFIG_COLDFIRE" makes me think "Isn't this always
true?"...

Well, It is for non-mmu parts (or coldfire with mmu) but not for 68020 and up.


Brad:
I believe this misrepresents the CPU32 feature set. According to the old
paper copy I have of the Motorola CPU32 reference manual, the only
unimplemented instructions relative to the 68020 are these:

1) Bit field instructions
2) Module call/return
3) RMW instructions (CAS/CAS2)
4) Coprocessor instructions
5) BCD instructions

The 64 bit MUL and DIV variants are explicitly listed in the instruction set.

The CPU32 is also missing some (but not all) of the addressing modes
which were added with the 68020.

I haven't worked with any of these chips in a long time, but the CPU32
is quite a bit newer and more complicated than a 68000 or 68010. I
did a project based on a 68332 about 15 years ago and still have all
the printed reference manuals for that particular chip.

Thanks for the detailed description.
Just like I answered to Greg, I didn't have a clear view of the differences.


Please ignore this patch. I'll make the changes according to what was
discussed in here and submit a new one.


Thanks,
Luis Alves
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