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Re: [Xen-devel] [PATCH] xen/arm: Propagate clock-frequency to DOMU if present in the DT timer node





On 03/06/2015 23:45, Chris (Christopher) Brand wrote:
Hi Julien,

Hi Chris,

When the property "clock-frequency" is present in the DT timer node, it means 
that the bootloader/firmware didn't correctly configured the
CNTFRQ/CNTFRQ_EL0 on each processor.
I will test this patch, but it doesn't apply cleanly to the version of Xen I'm 
currently using, so I need to update that first.

It's based on the latest staging.

I also looked at whether it would be possible to set the CNTFRQ register in the 
other cores when they come up. Eventually, I think we should do this in the 
(platform-specific) PSCI code. There doesn't seem to be a suitable hook in the 
platform-specific Xen code - it looks like all the code there related to 
bringing up secondary cores runs on the primary.

CNTFRQ is read-only in the hypervisor when the platform supports EL3 (i.e secure monitor).

So it has to be done either by the bootloader or by the firmware.

Regards,


--
Julien Grall

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