Re: [PATCH V4 1/2] dt-bindings: mailbox: Document qcom,ipq5424-tmel

[Sricharan Ramabadhran]

On 4/1/2025 12:59 PM, Sricharan Ramabadhran wrote:
> On 3/28/2025 1:32 PM, Krzysztof Kozlowski wrote:
> > On Thu, Mar 27, 2025 at 11:47:49PM +0530, Sricharan R wrote:
> > > +properties:
> > > +  compatible:
> > > +    items:
> > > +      - enum:
> > > +          - qcom,ipq5424-tmel
> >
> > blank line
> ok
>
> > > +  reg:
> > > +    maxItems: 1
> > > +
> > > +  interrupts:
> > > +    maxItems: 1
> > > +
> > > +  mboxes:
> > > +    maxItems: 1
> >
> > Why mbox is having an mbox? This does not look right and suggest the
> > block is misrepresented. I read the diagram and description two times
> > and still do not see how this fits there.
> TMEL/QMP secure functionalities are exposed to clients (like rproc) by 
> registering TMEL as mailbox controller. The IPC bit to communicate with 
> the TMEL/QMP controller itself is handled by the apcs mailbox. Hence
> it looks like a mbox inside mbox.
>
> Alternatively, would it be fine to fold the IPC bit handling in this 
> driver itself for doing the regmap_write (instead of connecting to
> apcs mailbox separately) ?
>
> Also, there are couple of other ways of designing this as well.
> Earlier i mentioned this in the RFC post [1] for getting the design
> sorted out.
>
> [1] https://lore.kernel.org/lkml/20241205080633.2623142-1- 
> quic_srichara@xxxxxxxxxxx/T/
>
> -------------------------------------------------------------
> Had the below mentioned in the RFC earlier.
>
> The intention of posting this is to get the design reviewed/corrected 
> since there are also other possible ways of having this SS support like:
>
> a) Make TMEL QMP as a 'rpmsg' driver and clients can connect using
>     rmpsg_send
>
> b) Keep TMEL APIs seperately in drivers/firmware which would export APIs
>     and QMP mailbox seperately.
>     Clients can then call the exported APIS.
>
> c) Combine both TMEL and QMP as mailbox (this is the approach used here)

Hi Krysztof,

Can you kindly provide your suggestion on how to proceed for the above ?
Would want to align on the design approach before posting the next
version.

Regards,
 Sricharan