Re: [PATCH V3 2/2] firmware: arm_scmi: add smc/hvc transport

[Sudeep Holla]

On Sat, Feb 29, 2020 at 02:07:30AM +0000, Peng Fan wrote:
> Hi Sudeep,
>
> > Subject: Re: [PATCH V3 2/2] firmware: arm_scmi: add smc/hvc transport
> >
> > On Wed, Feb 26, 2020 at 03:12:51PM +0800, peng.fan@xxxxxxx wrote:
> > > From: Peng Fan <peng.fan@xxxxxxx>
> > >
> > > Take arm,smc-id as the 1st arg, and protocol id as the 2nd arg when
> > > issuing SMC/HVC. Since we need protocol id, so add this parameter
> >
> > And why do we need protocol id here ? I couldn't find it out myself.
> > I would like to know why/what/how is it used in the firmware(smc/hvc
> > handler). I hope you are not mixing the need for multiple channel with
> > protocol id ? One can find out id from the command itself, no need to pass it
> > and hence asking here for more details.
>
> When each protocol needs its own shmem area, we need let firmware
> know which shmem area to parse the message from. Without protocol
> id, firmware not know which shmem area should use. Hope this is clear.
>

Not all platforms need to have a separate shmem for each protocol. Make it
it separate transport.

--
Regards,
Sudeep