SPARC32 SBus probing with OBP

[Mark Cave-Ayland]

Hi all,

Does anyone know how OBP probes for in-built SBus devices on SPARC32? 
The reason I'm asking is that I'm looking at trying to detect in-built 
devices in OpenBIOS, and the SBus documentation suggests that each slot 
contains Fcode mapped at offset 0 which is executed to build the device 
tree.

Now QEMU currently doesn't do any Fcode mapping within SBus slots, but 
according to its boot output OBP still manages to detect hardware such 
as graphics cards etc. within certain slots during boot. Is there a 
different mechanism used for detecting in-built devices, or is it just 
something as simple as a hardcoded list based upon the current machine type?

Many thanks,

Mark.

[Artyom Tarasenko]

On Sat, May 12, 2012 at 5:46 PM, Mark Cave-Ayland
 wrote:
> Hi all,
>
> Does anyone know how OBP probes for in-built SBus devices on SPARC32? The
> reason I'm asking is that I'm looking at trying to detect in-built devices
> in OpenBIOS, and the SBus documentation suggests that each slot contains
> Fcode mapped at offset 0 which is executed to build the device tree.
>
> Now QEMU currently doesn't do any Fcode mapping within SBus slots, but
> according to its boot output OBP still manages to detect hardware such as
> graphics cards etc. within certain slots during boot. Is there a different
> mechanism used for detecting in-built devices, or is it just something as
> simple as a hardcoded list based upon the current machine type?

I think it's the later. I had to implement a FCode stub for a dbri
device, as I played with the SS-20 OBP, because it just blindly tried
to execute the code there.

Artyom