[OpenBIOS] fdthree

[Blue Swirl]

On Tue, May 15, 2012 at 4:44 PM, Artyom Tarasenko <atar4qemu at gmail.com> wrote:
> On Mon, May 14, 2012 at 10:22 PM, Blue Swirl <blauwirbel at gmail.com> wrote:
>> On Mon, May 14, 2012 at 4:26 PM, Artyom Tarasenko <atar4qemu at gmail.com> wrote:
>>> Since none of the current Linux/sparc64 distributions has virtio
>>> drivers out of the box, it were nice to give the user ability to load
>>> them from a removable media.
>>> Currently Linux doesn't recognize our fdthree drive. The reason is
>>> simple - in OpenBIOS
>>>
>>> 0 > cd /pci/ebus/fdthree  ok
>>> 0 > .properties
>>> name                      "fdthree"
>>> reg                       00000000 00000000 00000000
>>>
>>> in ultra5's prtconf this property looks like this:
>>>
>>> reg:  00000014.003023f0.00000008.00000014.00706000.00000010.00000014.00720000.00000004
>>>
>>> The meaning of the first triple is clear - these are the fdc control
>>> registers. But what are the two other register sets?
>>>
>>> It looks like qemu has a normal PC floppy, connected to EBus. Probably
>>> it's not what Sun used to call fdthree?
>>> If fdthree is really something else, were there any UltraSPARC
>>> machines with PC floppy drives?
>>
>> I think the FDC was pretty standard 82077. The additional registers
>> could implement a DMA controller.
>
> It seems that in qemu the DMA controller sits on ISA, not on fdc? And
> that we don't have it in EBus?
> But I guess dma.c could be used directly as-is?

I'd expect the DMA controller (if the registers are DMA) to be more
like other Sparc DMA controllers, not 8237.

>
>> At least OpenBSD only seems to use
>> the 82077 registers:
>> http://fxr.watson.org/fxr/source/arch/sparc64/dev/fd.c?v=OPENBSD
>>
> --
> Regards,
> Artyom Tarasenko
>
> solaris/sparc under qemu blog: http://tyom.blogspot.com/search/label/qemu
>
> --
> OpenBIOS                 http://openbios.org/
> Mailinglist:  http://lists.openbios.org/mailman/listinfo
> Free your System - May the Forth be with you