Re: [OpenBIOS] fdthree

[Blue Swirl]

On Tue, May 15, 2012 at 4:44 PM, Artyom Tarasenko  wrote:
> On Mon, May 14, 2012 at 10:22 PM, Blue Swirl  wrote:
> > On Mon, May 14, 2012 at 4:26 PM, Artyom Tarasenko  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
>
> solaris/sparc under qemu blog: http://tyom.blogspot.com/search/label/qemu