Re: bisected regression: arm: omap3: voltage: fix channel configuration

[NeilBrown <neilb@suse.de>]

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On Tue, 24 Jul 2012 11:51:16 +0300 Tero Kristo <t-kristo@ti.com> wrote:

> On Tue, 2012-07-24 at 17:34 +1000, NeilBrown wrote:
> > On Tue, 24 Jul 2012 09:28:24 +0300 Tero Kristo <t-kristo@ti.com> wrote:
> > 
> > > On Tue, 2012-07-24 at 11:30 +1000, NeilBrown wrote:
> > 
> > > > Might there be some way to get it to scale higher than 600MHz?
> > > > The first message from U-boot says:
> > > > 
> > > > OMAP3630/3730-GP ES2.1, CPU-OPP2, L3-165MHz, Max CPU Clock 1 Ghz
> > > > 
> > > > and the board manufacturer thinks it should be capable of 800MHz.
> > > 
> > > You need to enable 800MHz OPP similarly to what is done in 
> > > beagle_opp_init() in board-omap3beagle.c. I am not sure what your board
> > > is detected as, depends on your boot loader (check /proc/cpuinfo.)
> > 
> > Thanks!
> > Yes, my board identifies as cpu_is_omap3630() so that code looks relevant.
> > I copied the opp_init across to my board file, it runs without complaining
> > but it now gets to
> > 
> > [ ok ] Loading cpufreq kernel modules...done (none).
> > [....] CPUFreq Utilities: Setting ondemand CPUFreq governor...CPU0...
> > 
> > 
> > and hangs.  magic SYSRQ doesn't respond.
> > 
> > Any hints?
> 
> You only enabled opp for 800MHz right? I am just wondering if the
> voltage levels for mpu / core opps are correct for your board... You may
> want to check the opp tables against the information provided by your
> board manufacturer. The trace about cpufreq enabling ondemand governor
> indicates it is switching to frequency throttling mode at that point, so
> it most likely tries to raise MPU frequency to 800MHz (CPU load is
> pretty high during boot.) You can try adding some trace to cpufreq
> driver itself to see what is happening.

Yes, just 800MHz.  I just copied the code from board-omap3beagle.c, so
it is actually 800MHz for MPU and 660MHz for IVA.

I tried running with that and with your patch reverted and it works
perfectly.  I even get 33% better speed on CPU-intensive workloads, so it
really is running at 800MHz.

> 
> Another thing to verify would be to check the voltage rails on your
> board schematics to see how the supply voltages are delivered.

I have a basic understanding of the schematics, but I don't really know what
to look for when it comes to power routing.
If you happen to have time and interest, the schematics are in the manual
that can be downloaded from 

    http://projects.goldelico.com/p/gta04-main/downloads/

I've got the GTA04A3, so GTA04A3-1-complete.pdf is the one you want.

Thanks,
NeilBrown

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