[PATCH v4 0/5] arm64,hi6220: Enable Hisilicon Hi6220 SoC

[Bintian]

Hello Will,

On 2015/5/7 20:57, Will Deacon wrote:
> On Thu, May 07, 2015 at 01:01:47PM +0100, Bintian wrote:
>> On 2015/5/7 19:25, Will Deacon wrote:
>>> On Thu, May 07, 2015 at 10:29:03AM +0100, Bintian wrote:
>>>> Hikey is a low cost board, I think it doesn't have an automatic thermal
>>>> cut out; I always use HiKey to test my patch, in the normal case,
>>>> temperature is not a problem.
>>>
>>> I don't see why the cost has anything to do with this issue; any money I
>>> save on the board will quickly be re-invested in my increased insurance
>>> premium.
>>>
>>> All I think we need is for secure software to keep an eye on the temperature
>>> and hit the power controller if it goes over some `fatal' threshold.
>>> Ideally, you'd be able to use a secure interrupt for this, but I suspect
>>> that you don't have the right hardware features for that (please correct me
>>> if I'm wrong). An alternative would be to hang something off a secure timer
>>> and get the firmware to check the board temperature on some low-frequency
>>> periodic tick.
>> If there is exception occurred on A core, there are two methods to
>> handle it:
>> (1) Delay for a period of time, watchdog will trigger the system reset.
>> (2) If the temperature is over 105 degree, the CPU will trigger reset(I
>> guess it's chip level).
>
> Aha, so now you're saying that there *is* a hardware shut-off at 105
> degrees, regardless of what the kernel is doing?
Yes!

> If that's the case, then
> we're fine and the current patches make sense in isolation.
Thank you very much and I need your ack in next version :)
I am preparing the next version and will send out soon.

Thanks,

Bintian

>
> Cheers,
>
> Will
>
> .
>