Re: [PATCH RFC 1/2] dt-bindings: soc: qcom,smsm: Allow specifying mboxes instead of qcom,ipc

[Luca Weiss]

On Donnerstag, 25. April 2024 18:17:15 MESZ Rob Herring wrote:
> On Wed, Apr 24, 2024 at 07:21:51PM +0200, Luca Weiss wrote:
> > The qcom,ipc-N properties are essentially providing a reference to a
> > mailbox, so allow using the mboxes property to do the same in a more
> > structured way.
> 
> Can we mark qcom,ipc-N as deprecated then?

Yes, that should be ok. Will also send a similar change to the other bindings
that support both qcom,ipc and mboxes.

>  
> > Since multiple SMSM hosts are supported, we need to be able to provide
> > the correct mailbox for each host. The old qcom,ipc-N properties map to
> > the mboxes property by index, starting at 0 since that's a valid SMSM
> > host also.
> > 
> > The new example shows how an smsm node with just qcom,ipc-3 should be
> > specified with the mboxes property.
> > 
> > Signed-off-by: Luca Weiss <luca@xxxxxxxxx>
> > ---
> >  .../devicetree/bindings/soc/qcom/qcom,smsm.yaml    | 48 ++++++++++++++++++----
> >  1 file changed, 40 insertions(+), 8 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
> > index db67cf043256..b12589171169 100644
> > --- a/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
> > +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml
> > @@ -33,6 +33,13 @@ properties:
> >        specifier of the column in the subscription matrix representing the local
> >        processor.
> >  
> > +  mboxes:
> > +    minItems: 1
> > +    maxItems: 5
> 
> Need to define what each entry is.

The entry is (description from qcom,ipc-N)

  "the outgoing ipc bit used for signaling the N:th remote processor."

So you want me to add 5 times e.g.

- the IPC mailbox used for signaling the 0th remote processor
- the IPC mailbox used for signaling the 1st remote processor

etc? I don't really have any extra knowledge on smsm to be able to write
something better there..

Also what are your thoughts on this binding vs the alternative I wrote
in the cover letter? I'm not really happy about how the properties are
represented.

Regards
Luca


> 
> > +    description:
> > +      Reference to the mailbox representing the outgoing doorbell in APCS for
> > +      this client.
> > +
> >    '#size-cells':
> >      const: 0
> >  
> > @@ -98,15 +105,18 @@ required:
> >    - '#address-cells'
> >    - '#size-cells'
> >  
> > -anyOf:
> > +oneOf:
> >    - required:
> > -      - qcom,ipc-1
> > -  - required:
> > -      - qcom,ipc-2
> > -  - required:
> > -      - qcom,ipc-3
> > -  - required:
> > -      - qcom,ipc-4
> > +      - mboxes
> > +  - anyOf:
> > +      - required:
> > +          - qcom,ipc-1
> > +      - required:
> > +          - qcom,ipc-2
> > +      - required:
> > +          - qcom,ipc-3
> > +      - required:
> > +          - qcom,ipc-4
> >  
> >  additionalProperties: false
> >  
> > @@ -136,3 +146,25 @@ examples:
> >              #interrupt-cells = <2>;
> >          };
> >      };
> > +  # Example using mboxes property
> > +  - |
> > +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> > +
> > +    shared-memory {
> > +        compatible = "qcom,smsm";
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +        mboxes = <0>, <0>, <0>, <&apcs 19>;
> > +
> > +        apps@0 {
> > +            reg = <0>;
> > +            #qcom,smem-state-cells = <1>;
> > +        };
> > +
> > +        wcnss@7 {
> > +            reg = <7>;
> > +            interrupts = <GIC_SPI 144 IRQ_TYPE_EDGE_RISING>;
> > +            interrupt-controller;
> > +            #interrupt-cells = <2>;
> > +        };
> > +    };
> > 
>