RE: [PATCH v11 2/2] mailbox: introduce ARM SMC based mailbox

[Peng Fan]

> Subject: Re: [PATCH v11 2/2] mailbox: introduce ARM SMC based mailbox
> 
> (+Viresh,Arnd)
> 
> On Mon, Dec 02, 2019 at 10:14:43AM +0000, Peng Fan wrote:
> > From: Peng Fan <peng.fan@xxxxxxx>
> >
> > This mailbox driver implements a mailbox which signals transmitted
> > data via an ARM smc (secure monitor call) instruction. The mailbox
> > receiver is implemented in firmware and can synchronously return data
> > when it returns execution to the non-secure world again.
> > An asynchronous receive path is not implemented.
> > This allows the usage of a mailbox to trigger firmware actions on SoCs
> > which either don't have a separate management processor or on which
> > such a core is not available. A user of this mailbox could be the SCP
> > interface.
> >
> 
> I would like to know all the use-cases for this driver ? 

Currently my usecase is SCMI.

Is this only for SCMI or
> will this get used with other protocols on the top. I assume the latter and
> hence it is preferred to keep this as a mailbox driver.
> 
> I am not against this approach but the reason I ask is to avoid duplication.
> Viresh has suggested abstraction of transport from SCMI driver to enable
> other transports[1]. Couple of transports that I am aware of is this SMC/HVC
> and the new(still in-concept) SPCI.
> 
> So I am looking for opinions on that approach. Please feel free to comment
> here or as part of that patch.

If we want to use SMC as transports, smc mailbox or smc transports(non-mailbox)
could be used. Both ok for me, smc transports just need write a new driver
under scmi folder.

I left the decision to you(scmi maintainer) and Jassi(mailbox maintainer),
Just hope the smc/hvc used as transports could be landed in upstream soon.

Thanks,
Peng.

> 
> --
> Regards,
> Sudeep
> 
> [1]
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