cpufreq support on Allwinner H3

[Emmanuel Vadot]

On Thu, 8 Mar 2018 12:33:44 +0100
Luc Hondareyte <hondareyte.luc at laposte.net> wrote:

> Le 08/03/2018 à 06:18, Emmanuel Vadot a écrit :
> > On Tue, 6 Mar 2018 20:59:37 +0100
> > Luc Hondareyte via freebsd-arm <freebsd-arm at freebsd.org> wrote:
> >
> >> Hi,
> >>
> >> I've just build 12-current for Allwinner H3  (armv7) and it seems that
> >> cpufreq support is missing (orangepi or nanopi):
> >   There is no opp table (freq<->voltage table) in the DTS that's why
> > it's not working.
> This thread? 
> http://lists.infradead.org/pipermail/linux-arm-kernel/2018-February/557940.html 

 Yep exactly.

> >   I think I've seen patches on the linux-arm kernel mailing list to add
> > them but even with thoses we will need support for the v2 opp.
> v2 opp? Does it mean that, as a workaround, with the appropriate DTS 
> patch and a switch back to armv6, this should work?

 Switch back to armv6 will change nothing but a patched dtb will do the
job. That what we had before and that's why on ganbold@ images cpufreq
works.
 Since I don't want patched DTB in the tree our only option is to
implement v2 opp table in sys/dev/cpufreq/cpufreq_dt.c and wait that
the dts is updated upstream.

> I say that because, 
> on nanopi neo, with the "old" 12-current image build by Ganbold 
> Tsagaankhuu (that was available on FriendlyArm Wiki), cpu_freq support 
> is OK and it?s run at full speed:
> 
> root at allwinner-h3:~ # uname -a
> FreeBSD allwinner-h3 12.0-CURRENT FreeBSD 12.0-CURRENT #7 r308116M: Mon 
> Oct 31 10:56:20 ULAT 2016 
> tsgan at beastie.mstride.com:/usr/obj/arm.armv6/usr/src/sys/GENERIC arm
> root at allwinner-h3:~ # sysctl dev.cpu.0.freq
> cpufreq: get returning known freq 1008
> cpufreq: get returning known freq 1008
> dev.cpu.0.freq: 1008
> 
> And this image does not seem to use Linux DTS.
> >> root at allwinner-h3:~ # service powerd onestart
> >> Starting powerd.
> >> powerd: no cpufreq(4) support -- aborting: No such file or directory
> >> /etc/rc.d/powerd: WARNING: failed to start powerd
> >>
> >> So, on nanopi neo, it's slowdown (not on orange-pi that seems to run at
> >> full speed). I am using a custom kernel conf that just contains:
> >>
> >> include GENERIC
> >> nooptions       INVARIANTS
> >> nooptions       INVARIANT_SUPPORT
> >> nooptions       WITNESS
> >> nooptions       WITNESS_SKIPSPIN
> >> nooptions       BUF_TRACKING
> >> nooptions       DEADLKRES
> >> nooptions       FULL_BUF_TRACKING
> >>
> >   You can use the GENERIC-NODEBUG for that
> >
> Oh, I missed that. Thanks.


-- 
Emmanuel Vadot <manu at bidouilliste.com> <manu at freebsd.org>