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

[Suriyan Ramasami <suriyan.r@xxxxxxxxx>]

On Tue, Mar 18, 2014 at 6:37 AM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> 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.
>
I am also trying to fix it in the boot loader. Nonetheless, I have a
gap in my understanding as to why using clock-frequency in domU would
create a problem?
If its OK for dom0 and domU to use clock-frequency in the case that
CNTFRQ comes up as 0, I would definitely submit a patch.

>> 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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