Re: [PATCH 0/2] SH7709 DMA fixes

[Rich Felker]

On Sat, May 06, 2023 at 05:25:01PM +0200, John Paul Adrian Glaubitz wrote:
> Hi Artur!
> 
> Thanks a lot for your patches!
> 
> On Sat, 2023-05-06 at 16:17 +0200, Artur Rojek wrote:
> > this series provides fixes to the SH7709 DMA controller, allowing the HP
> > Jornada 680 palmtop to boot Linux again. To my knowledge, this is the
> > first time in ~14 years someone tests upstream Linux on this device. And
> > with the included patches applied, I'm happy to announce that it still
> > works like a charm.
> 
> Wow, that sounds great! I will be happy to review your patches.
> 
> > PS. What might be of interest to the sh-linux community, there's further
> > work towards this platform in my pipeline. E.g. I've added support for
> > the HD6446x PCMCIA controller, allowing Jornada 680 to use Ethernet and
> > Wi-Fi cards. However, what prevents proper upstream of such a driver is
> > the crude and antiquated code of the underlying platform base. For
> > example, the HD6446x bridge (`cchips/hd6446x/hd64461.c`) lacks the
> > concept of clocks, preventing the PCMCIA driver from hardware agnostic
> > clock gating. So what I'm looking into next is the cleanup of existing
> > platform code base, bringing it up-to-date with modern kernel APIs.
> > Hopefully it's not trying to bite more than I can chew, but eventually
> > ending up with Device Tree support would be really nice :)
> 
> Yes, there is still a lot of modernization work to be done for SuperH!
> 
> Device tree has actually been worked on in the past and there is a patch
> set by Yoshinori Sato to add support for device tree that got never merged,
> see [1].
> 
> Geert and I are planning to have another look at these patches and see whether
> we can get them into a shape where they can be merged. Maybe you can help us
> with that effort.

At one point I tried to rebase these to run on what was (at the time)
current, and had partial success -- I got it to start booting with DT
under qemu, but my work rebasing the PCI stuff had problems and IIRC
prevented getting virtio working -- it was crashing at that stage. If
there's interest I can see if I can dig up that rebased branch in case
it would be useful to look at. It probably has mistakes but might be a
start for looking at what changed out from under the patches that
needs to change.

Rich