Re: [Xen-devel] [ARM:PATCH v2 1/1] Pass the timer clock-frequency to DOM0

[Suriyan Ramasami <suriyan.r@xxxxxxxxx>]

On Fri, Apr 11, 2014 at 9:32 AM, Julien Grall <julien.grall@xxxxxxxxxx> wrote:
> Hello,
>
> On 04/11/2014 05:05 PM, Suriyan Ramasami wrote:
>> On Tue, Apr 1, 2014 at 4:12 AM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
>>> On Fri, 2014-03-28 at 14:04 +0000, Julien Grall wrote:
>>>> That made me think that this is the only board with this issue. I would
>>>> definitely prefer to fix the clock frequency in U-boot. The bootloader
>>>> should respect the ARM ARM (see B.8.1.1):
>>>>
>>>> "The CNTFRQ register is UNKNOWN at reset, and therefore the counter
>>>> frequency must written to CNTFRQ as part
>>>> of the system boot process."
>>>
>>> Yes, Suriyan, please exhaust this avenue of attack (fixing u-boot on the
>>> platform) first.
>>>
>> Thank you gentlemen for your comments.
>> The problem with this board is that the uboot is not entered in secure
>> mode, and hence the mcr indstruction to set the ARCH timer frequency
>> cannot be executed in u-boot.
>
> If so, what is the state of the CPU when it jumps to U-boot?
> The CPU has to be either in secure mode or hyp mode.
> AFAIK, if it's NS you won't be able to go in hyp mode, unless crash the
> CPU...
>
The CPU is in HYP mode when it jumps to U-boot.
Thanks
- Suriyan

> Regards,
>
> --
> Julien Grall

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