Re: [PATCH v1 1/3] dt-bindings: soc: qcom: eud: Update compatible strings for eud

[Melody Olvera]

On 8/14/2024 3:30 AM, Konrad Dybcio wrote:
> On 14.08.2024 8:15 AM, Krzysztof Kozlowski wrote:
> > On 13/08/2024 22:03, Melody Olvera wrote:
> > > On 8/8/2024 4:00 AM, Krzysztof Kozlowski wrote:
> > > > On 07/08/2024 20:32, Melody Olvera wrote:
> > > > > The EUD can more accurately be divided into two types; a secure type
> > > > > which requires that certain registers be updated via scm call and a
> > > > > nonsecure type which must access registers nonsecurely. Thus, change
> > > > > the compatible strings to reflect secure and nonsecure eud usage.
> > > > >
> > > > > Signed-off-by: Melody Olvera <quic_molvera@xxxxxxxxxxx>
> > > > > ---
> > > > >    Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml | 6 +++---
> > > > >    1 file changed, 3 insertions(+), 3 deletions(-)
> > > > >
> > > > > diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml
> > > > > index f2c5ec7e6437..476f92768610 100644
> > > > > --- a/Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml
> > > > > +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml
> > > > > @@ -17,8 +17,8 @@ properties:
> > > > >      compatible:
> > > > >        items:
> > > > >          - enum:
> > > > > -          - qcom,sc7280-eud
> > > > > -      - const: qcom,eud
> > > > > +          - qcom,secure-eud
> > > > > +          - qcom,eud
> > > > Commit msg did not explain me why DT bindings rules are avoided here and
> > > > you drop existing SoC specific compatible.
> > > >
> > > > This really does not look like having any sense at all, I cannot come up
> > > > with logic behind dropping existing users. You could deprecate it, but
> > > > then why exactly this device should have exception from generic bindings
> > > > rule?
> > > Understood. I won't drop this compatible string. Is alright to add the
> > > additional compatible as is?
> > You always need SoC specific compatible.
> Melody, is there any way to discover (that won't crash the board if we
> guess wrong) whether secure accessors are needed?

Unfortunately, no. We considered several options, but none guarantee 
that we will avoid
a crash if we try non-securely. The secure call also won't give a 
specific error if it fails either
(for security reasons) so we can't know if a secure access failed 
because it's supposed to be
accessed non-securely or for another reason; hence this approach. If there's
another way to achieve this functionality that might be better, I'm all 
ears.

Thanks,
Melody