Re: [hatari-devel] SCU/VME register access?

[Eero Tamminen <oak@xxxxxxxxxxxxxx>]

Hi,

On 4/6/20 1:47 PM, Eero Tamminen wrote:
> On 4/6/20 10:57 AM, Nicolas Pomarède wrote:
> > instead of making these registers configurable at build-time, I'd 
> > rather we go through the specs of the megaste / tt and see which 
> > registers exactly should be emulated on both machine and whether they 
> > cause a bus error or not.
....
> VME / SCU is for interfacing with add-on devices
> on the VME bus.
>
> Linux checks accessibility of SCU mask register to
> see whether it will map VME address range and set
> up autovector stuff, whereas TOS v2 just checks register accessibility 
> to detect MegaSTE.
>
> Here are some relevant places in Linux code...
>
> Detection:
> https://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k.git/tree/arch/m68k/atari/config.c#n324 
>
>
> Comment on address mapping:
> https://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k.git/tree/arch/m68k/atari/config.c#n395 
>
>
> Integrating Atari interrupt handling to rest of m68k:
> https://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k.git/tree/arch/m68k/atari/ataints.c#n8 
>
>
> MFP & SCC interrupts are enabled in VME mask:
> https://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k.git/tree/arch/m68k/atari/ataints.c#n303 

Spec here lists VME interrupts, clocks and address space:
http://dev-docs.atariforge.org/files/VME_Spec_7-19-1991.pdf



	- Eero