RE: [PATCH v5 1/2] dt-bindings: mailbox: add binding doc for the ARM SMC/HVC mailbox

From: Peng Fan
Date: Fri Aug 30 2019 - 05:40:41 EST


Hi Sudeep

> Subject: Re: [PATCH v5 1/2] dt-bindings: mailbox: add binding doc for the ARM
> SMC/HVC mailbox
>
> On Fri, Aug 30, 2019 at 07:37:41AM +0000, Peng Fan wrote:
> > Hi Jassi,
> > > > I think there could be channel for TEE, and channel for Linux.
> > > > For virtualization case, there could be dedicated channel for each VM.
> > > >
> > > I am talking from Linux pov. Functions 0xfe and 0xff above, can't
> > > both be active at the same time, right?
> >
> > If I get your point correctly,
> > On UP, both could not be active. On SMP, tx/rx could be both active,
> > anyway this depends on secure firmware and Linux firmware design.
> >
>
> Just to confirm, we can't have SMC/HVC based Rx channel as there's no
> *architectural* way to achieve it. So it can be based on some interrupt from
> secure side and hence will be a *different* type of channel/controller.
>
> Sorry to make this point repeatedly, but juts to be absolutely clear:
> as it stands, SMC/HVC can be used only for Tx today.

Since interrupt notification was dropped in v5, I need to drop RX description
in v6.

Thanks,
Peng.

>
> --
> Regards,
> Sudeep