Re: amigappc test kernel for CSPPC and BPPC

[Frank Wille <frank%phoenix.owl.de@localhost>]

Jukka Anberg wrote:

> I got it to boot now. Luckily there were no other problems than pmap
> not taking fast memory and that dcbz+memory coherence issue discussed
> earlier.
>
> ftp.netbsd.org:/pub/NetBSD/misc/jandberg/amigappc/20101205/bppc-pmap.diff
> There is a new option to set maximum address used for pmap allocations.

Would be interesting to know why there is a maximum address at all? Maybe
the intention was not to set a maximum address, but to restrict page tables
and pmap allocations to a single 256MB region, because you don't want to
use more than one BAT for it?


> Another option disables use of dcbz in kernel. And third disables the
> use of memory coherence bit bit in page tables. 

Perhaps I have to read the whole thread again, but at the moment I don't
understand why this is still needed, since pmap is allowed to use the
on-board Fast RAM now, same as a CSPPC.

And shouldn't dcbz at least work when you disable memory coherency?

It could be interesting if Radek finds some time to test your modifications
and disables the last two options just to see what happens. I see no reason
why it should work differently on a CSPPC than on a BPPC once you have your
pmap allocations in Fast RAM.

I just tested your patches with my CSPPC and can confirm that it does no
harm to it. ;)


> I think this is going to need some more work. Hopefully a better
> solution to the dcbz problem could be found.

Yes. The first option is ok and can be argumented. But the other two are
strange.


>
ftp.netbsd.org:/pub/NetBSD/misc/jandberg/amigappc/20101205/bppc-identify.diff
> Some small changes to have the machine identification printed
> correctly. My bppc board has type 'H' and version 7 processor is called
> 603ev instead of 603e+ by the common powerpc code so we might as well.
> I think that this is the only part that I feel confident about
> committing at this point. ;)

Your confidence is justified. Commit it! :)


> Also it looks like cpuclock/busclock calculation is a bit off.
> This one should have 200Mhz processor instead of 233Mhz.

Have a look at the pll603[] array in amigappc_identify(). There is probably
a wrong entry for your CPU.

-- 
Frank Wille