Re: [RFC 13/13] m68k: mac: convert to generic clockevent

Finn Thain
2020-11-06T02:52:01Z

On Fri, 23 Oct 2020, Geert Uytterhoeven wrote:

> > > > The arm/rpc timer seems to be roughly in the same category as most
> > > > of the m68k ones or the i8253 counter on a PC. It's possible that
> > > > some of them could use the same logic as
> > > > drivers/clocksource/i8253.o as long as there is any hardware
> > > > oneshot mode.
> > >
> > > There appear to be 15 platforms in that category. 4 have no
> > > clocksource besides the jiffies clocksource, meaning there's no
> > > practical alternative to using a periodic tick, like you did in your
> > > RFC patch:
> > >
> > > arch/m68k/apollo/config.c
> > > arch/m68k/q40/q40ints.c
> > > arch/m68k/sun3/sun3ints.c
> > > arch/m68k/sun3x/time.c
> >
> > Do any of these have users? I'm fairly sure sun3x has never worked in
> > mainline, sun3 seems to still need the same few patches it did 20
> > years ago. I couldn't find much about Linux on Apollo or q40, the
> > information on the web for either of them seems to all be for
> > linux-2.4 kernels.
>
> They probably don't have any users.

I have access to several Sun 3 machines but no time to work on that port,
unfortunately.

Are these 4 platforms (those with no clocksource besides the "jiffies"
clocksource) the only reason for CONFIG_TIME_LOW_RES on m68k?