[OpenBIOS] (no subject)

[Mark Cave-Ayland]

On 06/06/14 11:15, BALATON Zoltan wrote:

> On Fri, 6 Jun 2014, Mark Cave-Ayland wrote:
>> SPARC64 and PPC. I guess something in arch/ppc must try and redefine the
>> milliseconds word somewhere - if you could locate the duplicate
>> definition (and even better submit a patch to remove it), that would be
>> a great help. As you can see, I'm a bit short on time at the moment...
>
> I've found these:
>
> arch/ppc/briq/methods.c:ciface_milliseconds( unsigned long args[],
> unsigned long ret[] )
> arch/ppc/briq/methods.c:        { "milliseconds",
> ciface_milliseconds     },
> arch/ppc/mol/methods.c:ciface_milliseconds( unsigned long args[],
> unsigned long ret[] )
> arch/ppc/mol/methods.c: { "milliseconds",       ciface_milliseconds     },
> arch/ppc/pearpc/methods.c:ciface_milliseconds( unsigned long args[],
> unsigned long ret[] )
> arch/ppc/pearpc/methods.c:      { "milliseconds",
> ciface_milliseconds     },
> arch/ppc/qemu/methods.c:ciface_milliseconds( unsigned long args[],
> unsigned long ret[] )
> arch/ppc/qemu/methods.c:        { "milliseconds",
> ciface_milliseconds     },
>
> Should these all be removed? They all seem to be different. Is the
> default (dummy) implementation now better instead of these?

Heh well that's the first time I've noticed that code. It's completely 
wrong - for starters, it uses a fixed TB instead of using the one from 
QEMU so it's not going to measure time accurately anyhow.

The correct thing to do is similar to SPARC in that you create a 100Hz 
interrupt (possibly using the PPC decrementer?) that should increment a 
variable representing the number of ms elapsed. All you need to do is 
then point the new code towards that variable and it will handle 
get-msecs and milliseconds automatically.

The interrupt routine is probably do-able in about 20 lines or less of 
PPC asm but it's beyond my current PPC-fu. It would be a good project 
for you though, and would probably fix the incorrect timing CIF 
milliseconds with -M mac99 :)


ATB,

Mark.