On Wed, Jan 20, 2021 at 02:57:19PM +0100, Mark Kettenis wrote:
> > Date: Wed, 20 Jan 2021 14:12:07 +0100
> > From: "Peter J. Philipp" <p...@centroid.eu>
> >
> > Hi list,
> >
> > Last year I set out for a year to port G5 to 64-bit and I started this year
> > with converting OFW to FDT. Yesterday was my first day back at this, and I
> > made some results happen. In fact walking Openfirmware and adding it to the
> > FDT (Mark hinted to me the arm64 fdt.{c,h} which was brilliant) does create
> > a nice DTB that I think I can work with. Only there is one problem...
> >
> > As I walk the properties in OFW and insert them in FDT the order is
> > reversed.
> > I don't know if that will cause any conversion problems with drivers, I had
> > a glance at /sys/arch/macppc/dev/zs.c and that doesn't care the order of it,
> > but something in me says that name property should always come first, am I
> > mistaken in this?
>
> The order shouldn't be important. We can probably adjust the code to
> in fdt.c to add properies in the "right" order.
>
> > Anyhow I tried loading the powerpc64 kernel to the loader but it still blows
> > up before dmesg, I didn't luck out. I'll have to port the powerpc64 to the
> > macppc64 stuff and compile a kernel. I think I'll have to do something
> > about the slb's anyhow as those are not supported in the 970 processor.
>
> The PowerPC 970 processor has 64 SLBs. The OpenBSD/powerpc64 kernel
> uses 32 SLBs, so this should all work.
>
> The kernel expects to be starting with the SF and HV bits set and the
> DR and IR bits cleared in the MSR register. So your bootloader will
> have to switch to that mode.
>
> You'll need some sort of early console. That is currently only
> implemented for OPAL firmware. Given that these machines don't have a
> usable serial port, you'll probably need to implement a framebuffer
> console. Since OpenFirmware already initializes the framebuffer that
> shouldn't be too difficult. You could take a look at how arm64 uses
> dev/fdt/simplefb.c to set this up.
>
> Cheers,
>
> Mark
Awesome, thanks Mark! I know what to do then :-). I'll work tomorrow at
sharing the code that I've made so far you'll be able to find it best when
checking https://centroid.eu/ppc occasionally. I also am working off a
tree from december I'll have to merge a -current tree in to this. It seems
there is enough work to do for a month anyhow :-).
Best Regards,
-peter
