[PATCH] ARM: dts: am335x-pocketbeagle: choose tick-timer

[Nishanth Menon]

On 09:27-20230909, Trevor Woerner wrote:
> On Fri 2023-09-08 @ 12:36:17 PM, Nishanth Menon wrote:
> > On 11:25-20230830, Trevor Woerner wrote:
> > > Commit 4b2be78ab66c ("time: Fix get_ticks being non-monotonic")
> > > requires '/chosen/tick-timer' in device-tree. Otherwise we get:
> > > 
> > > 	U-Boot 2023.07.02 (Jul 11 2023 - 15:20:44 +0000)
> > > 
> > > 	CPU  : AM335X-GP rev 2.1
> > > 	Model: TI AM335x PocketBeagle
> > > 	DRAM:  512 MiB
> > > 	Core:  154 devices, 16 uclasses, devicetree: separate
> > > 	Could not initialize timer (err -19)
> > > 
> > > 	resetting ...
> > > 
> > > Suggested-by: Pierre Lebleu <pierre.lebleu at pile-engineering.com>
> > > Signed-off-by: Trevor Woerner <twoerner at gmail.com>
> > > ---
> > >  arch/arm/dts/am335x-pocketbeagle.dts | 1 +
> > >  1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/arch/arm/dts/am335x-pocketbeagle.dts b/arch/arm/dts/am335x-pocketbeagle.dts
> > > index b379e3a5570d..02e3aac56064 100644
> > > --- a/arch/arm/dts/am335x-pocketbeagle.dts
> > > +++ b/arch/arm/dts/am335x-pocketbeagle.dts
> > > @@ -15,6 +15,7 @@
> > >  
> > >  	chosen {
> > >  		stdout-path = &uart0;
> > > +		tick-timer = &timer2;
> > >  	};
> > >  
> > >  	leds {
> > > -- 
> > > 2.41.0.327.gaa9166bcc0ba
> > > 
> > 
> > Does enabling CONFIG_SYS_ARCH_TIMER solve this?

[...]

> Getting the code to compile with CONFIG_SYS_ARCH_TIMER would require a deeper
> reworking of the configuration/Make logic in order to swap out the functions
> in arch/arm/mach-omap2/timer.c for the ones in
> arch/arm/cpu/armv7/arch_timer.c. The definitions of those functions in both
> those locations are quite different, so even after getting the build to work
> there's no guarantee the arch functions would work.

The difference is using SoC level dmtimer vs cpu level arch timer.
Either way, it will be good to send this upstream kernel.org.

Looking at the trm[1], it looks like arch timer isn't there for
cortex-a8?

[1] https://developer.arm.com/documentation/ddi0344/latest/

-- 
Regards,
Nishanth Menon
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