Re: [PATCH] arm64: dts: qcom: sa8775p: fix the secure device bootup issue

[Jie Gan]

On 12/20/2024 5:25 AM, Konrad Dybcio wrote:
> On 19.12.2024 3:52 AM, Jie Gan wrote:
> > The secure device(fused) cannot bootup with TPDM_DCC device. So
> > disable it in DT.
> >
> > Fixes: 6596118ccdcd ("arm64: dts: qcom: Add coresight nodes for SA8775p")
> > Signed-off-by: Jie Gan <quic_jiegan@xxxxxxxxxxx>
> > ---
>
> I was thinking, is there a QFPROM fuse we could read on both
> secure and non-secure devices to determine whether all coresight
> components will be accessible, and enable them based on that
> information?
There are two known TPDM devices had been disabled on secure device. One 
of these devices is TPDM_DCC. In downstream code, we have an API to 
check the secure status of the device in TPDM's probe function, to avoid 
unintentional enable. The downstream API will check the register that 
controls crash dump functionality in TZ and the crash dump functionality 
is disabled by default on secure devices.

We need to verify if the downstream API is supported by the upstream 
kernel. We plan to upstream a patch to implement this functionality in 
the TPDM driver or any other device's driver that needed the functionality.

For the time being, we need to disable this TPDM device in DT because 
the TPDM_DCC will break the bootup process on secure devices.

> Konrad

Thanks,
Jie