Re: [PATCH 8/9] arm64: dts: qcom: add IPQ5210 SoC and rdp504 board support

[Sumit Garg]

Hey Konrad,

On Mon, Mar 16, 2026 at 3:05 PM Konrad Dybcio
<konrad.dybcio@xxxxxxxxxxxxxxxx> wrote:
>
> On 3/16/26 10:03 AM, Kathiravan Thirumoorthy wrote:
> >
> > On 3/13/2026 6:18 PM, Konrad Dybcio wrote:
> >> On 3/11/26 10:45 AM, Kathiravan Thirumoorthy wrote:
> >>> Add initial device tree support for the Qualcomm IPQ5210 SoC and
> >>> rdp504 board.
> >>>
> >>> Signed-off-by: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@xxxxxxxxxxxxxxxx>
> >>> ---
>
> [...]
>
> >>> +    firmware {
> >>> +        optee {
> >>> +            compatible = "linaro,optee-tz";
> >>> +            method = "smc";
> >>> +        };
> >>> +
> >>> +        scm {
> >>> +            compatible = "qcom,scm-ipq5210", "qcom,scm";
> >>> +        };
> >> OP-TEE *and* SCM? What does the former do?
> >
> > For OP-TEE, we have use cases like getting the random numbers, remoteproc PAS and few others.
> >
> > For SCM, setting the download mode is one typical example where OP-TEE doesn't come into picture.
> >
> > Please let me know if this helps.
>
> I think it does, but it's odd that OPTEE wouldn't handle both
>

The SCM calls are the ones handled by TF-A which are usually referred
to as SiP SMC calls. OP-TEE doesn't handle those SiP calls but only
the SMC calls in trusted OS range. So yeah both nodes have to be
there.

> fwiw +Sumit is poking at OSS firmware for other platforms and may be
> interested
>

I think this is a WIN family chipset which only supports OP-TEE by
default. In the IoT chipsets there can either be QTEE or OP-TEE and
the bootloader (U-Boot) apply a DT fixup for OP-TEE in case it's
present.

-Sumit