Re: [Xen-devel] ARM: EXYNOS 5410 - DOM0 not being scheduled

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Tue, 2014-03-18 at 12:04 +0000, Julien Grall wrote:
> Hi Ian,
> 
> On 03/18/2014 09:52 AM, Ian Campbell wrote:
> > On Mon, 2014-03-17 at 22:15 +0000, Julien Grall wrote:
> >>> 2. arch_timer_rate coming up as 0 in dom0 inspite of the dtb defining
> >>> clock-frequency.
> >>
> >> The clock-frequency properties is not given to dom0. It should be able 
> >> to retrieve the frequency from the timer (CNTFRQ). That would mean that 
> >> u-boot is not correctly set up the frequency (it's the only one able to 
> >> do it as it need to be done in secure world).
> > 
> > If the clock-frequency property is present in the host DT then that
> > would imply that secure world is not setting CNTFRQ or is setting it
> > wrong (since the property is effectively a workaround for that exact
> > bug). Perhaps we should propagate it if it is present?
> 
> It's easy to do it for dom0, what about guests? I think it would be
> better to let the bootloader to set up the frequency. I'm a bit
> surprised that it's not already the case for this board.

Well, that's the issue -- sometimes we just need to deal with what the
hardware/firmware gives us. I suppose on all the existing platforms we
can just fix the firmware, I'm certainly not arguing that someone
shouldn't also send a patch for the firmware on this platform to the
appropriate place.

> For instance, on the Arndale the property "clock-frequency" exists but
> CNTFRQ is also correctly set.

That's harmless, if a bit stupid.

> > While grepping about this I noticed that make_timer_node doesn't use
> > DT_MATCH_TIMER, which I guess is just an accidental oversight, perhaps
> > if someone is fixing the clock-frequency issue they could throw in a
> > second patch for this too?
> 
> I think it's an error during the cleanup.
> 
> Regards,
> 



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