Re: [PATCH 2/4] dt-bindings: memory: mediatek: Add smi-sub-common property for reset

[AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>]

Il 24/10/24 03:28, Friday Yang (杨阳) ha scritto:
> On Wed, 2024-08-21 at 10:55 +0200, Krzysztof Kozlowski wrote:
> >   	
> > External email : Please do not click links or open attachments until
> > you have verified the sender or the content.
> >   On 21/08/2024 10:26, friday.yang wrote:
> > > On the MediaTek platform, some SMI LARBs are directly linked to SMI
> > > common. While some SMI LARBs are linked to SMI sub common, then SMI
> > > sub common is linked to SMI common. Add 'mediatek,smi-sub-comm' and
> > > 'mediatek,smi-sub-comm-in-portid' properties here. The SMI reset
> > > driver could query which port of the SMI sub common the current
> > LARB
> > > is linked to through the two properties. The hardware block diagram
> > > could be described as below.
> > >
> > >               SMI Common(Smart Multimedia Interface Common)
> > >                   |
> > >           +----------------+-------
> > >           |                |
> > >           |                |
> > >           |                |
> > >           |                |
> > >           |                |
> > >         larb0       SMI Sub Common
> > >                     |      |     |
> > >                    larb1  larb2 larb3
> > >
> > > Signed-off-by: friday.yang <friday.yang@xxxxxxxxxxxx>
> > > ---
> > >   .../mediatek,smi-common.yaml                  |  2 ++
> > >   .../memory-controllers/mediatek,smi-larb.yaml | 22
> > +++++++++++++++++++
> > >   2 files changed, 24 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/memory-
> > controllers/mediatek,smi-common.yaml
> > b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-
> > common.yaml
> > > index 2f36ac23604c..4392d349878c 100644
> > > --- a/Documentation/devicetree/bindings/memory-
> > controllers/mediatek,smi-common.yaml
> > > +++ b/Documentation/devicetree/bindings/memory-
> > controllers/mediatek,smi-common.yaml
> > > @@ -39,6 +39,7 @@ properties:
> > >             - mediatek,mt8186-smi-common
> > >             - mediatek,mt8188-smi-common-vdo
> > >             - mediatek,mt8188-smi-common-vpp
> > > +          - mediatek,mt8188-smi-sub-common
> > >             - mediatek,mt8192-smi-common
> > >             - mediatek,mt8195-smi-common-vdo
> > >             - mediatek,mt8195-smi-common-vpp
> > > @@ -107,6 +108,7 @@ allOf:
> > >           compatible:
> > >             contains:
> > >               enum:
> > > +              - mediatek,mt8188-smi-sub-common
> > >                 - mediatek,mt8195-smi-sub-common
> > >       then:
> > >         required:
> > > diff --git a/Documentation/devicetree/bindings/memory-
> > controllers/mediatek,smi-larb.yaml
> > b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-
> > larb.yaml
> > > index 2381660b324c..5f162bb360db 100644
> > > --- a/Documentation/devicetree/bindings/memory-
> > controllers/mediatek,smi-larb.yaml
> > > +++ b/Documentation/devicetree/bindings/memory-
> > controllers/mediatek,smi-larb.yaml
> > > @@ -69,6 +69,16 @@ properties:
> > >       description: the hardware id of this larb. It's only required
> > when this
> > >         hardware id is not consecutive from its M4U point of view.
> > >   
> > > +  mediatek,smi-sub-comm:
> > > +    $ref: /schemas/types.yaml#/definitions/phandle
> > > +    description: a phandle of smi_sub_common that the larb is
> > linked to.
> >
> > Why do you have to smi phandle properties per each node?
>
> As shown in the picture from the commit message, we have multipule smi-
> sub-common, each SMI larb may link to one of the smi-sub-common. So we
> need the 'mediatek,smi-sub-comm' to describe which smi-sub-common the
> larb is linked to.
> In next version, I will add two smi-sub-common to the diagram in the
> commit message.
>
> > > +
> > > +  mediatek,smi-sub-comm-in-portid:
> > > +    $ref: /schemas/types.yaml#/definitions/uint32
> > > +    minimum: 0
> > > +    maximum: 7
> > > +    description: which port of smi_sub_common that the larb is
> > linked to.
> >
> > Merge it into phandle.
>
> Just confirm,
> Do you mean merge these two into one property, like:
> mediatek,smi-sub-comm = <&phandle port-id>;
>
> > > +
> > >   required:
> > >     - compatible
> > >     - reg
> > > @@ -125,6 +135,18 @@ allOf:
> > >         required:
> > >           - mediatek,larb-id
> > >   
> > > +  - if:
> > > +      properties:
> > > +        compatible:
> > > +          contains:
> > > +            enum:
> > > +              - mediatek,mt8188-smi-larb
> > > +
> > > +    then:
> > > +      required:
> > > +        - mediatek,smi-sub-comm
> > > +        - mediatek,smi-sub-comm-in-portid
> > > +
> >
> > and add it to the example (since you claim it is valid for every
> > device).

It's valid only for the Local Arbiters that have a sub-common port, which anyway
are only the ones that are used by CAMSYS if I'm not wrong....

Regardless of that, not all of the mt8188-smi-larb *require* smi-sub-comm.

Besides, if the larb is anyway already linked to a sub-common, can't we just grab
that from walking back?
Or is this property's purpose to actually add a link to a sub-common?

Regards,
Angelo

> OK, I will add this to the example.
>
> > Best regards,
> > Krzysztof