RE: [PATCH v5 1/4] dt-bindings: firmware: Add bindings for ZynqMP firmware

[Jolly Shah]

Hi Sudeep,

> -----Original Message-----
> From: Sudeep Holla [mailto:sudeep.holla@xxxxxxx]
> Sent: Thursday, March 08, 2018 3:48 AM
> To: Jolly Shah <JOLLYS@xxxxxxxxxx>
> Cc: gregkh@xxxxxxxxxxxxxxxxxxx; matt@xxxxxxxxxxxxxxxxxxx;
> hkallweit1@xxxxxxxxx; michal.simek@xxxxxxxxxx; robh+dt@xxxxxxxxxx;
> mark.rutland@xxxxxxx; Sudeep Holla <sudeep.holla@xxxxxxx>;
> ard.biesheuvel@xxxxxxxxxx; mingo@xxxxxxxxxx; keescook@xxxxxxxxxxxx;
> dmitry.torokhov@xxxxxxxxx; Rajan Vaja <RAJANV@xxxxxxxxxx>; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v5 1/4] dt-bindings: firmware: Add bindings for ZynqMP
> firmware
> 
> 
> 
> On 07/03/18 22:25, Jolly Shah wrote:
> > Hi Sudeep,
> >
> 
> [...]
> 
> >>> +Examples:
> >>> +	firmware {
> >>> +		zynqmp_firmware: zynqmp-firmware {
> >>> +			compatible = "xlnx,zynqmp-firmware";
> >>> +			method = "smc";
> >>> +		};
> >>> +	};
> >>>
> >>
> >> Do you foresee using SMC/HVC for this firmware even on future platforms?
> >> If not, I suggest to keep the protocol part separate from the transport i.e.
> >> smc/hvc via ATF. It could be replaced with mailbox or some h/w
> >> mechanism in future ?
> >>
> >
> > We have PSCI and EEMI interfaces exposed to linux from ATF. PSCI is an
> > EEMI client. We do not have current plans to switch to mailbox as it
> > will require 2 communication channels to PMU as PSCI is through ATF.
> >
> 
> OK, but I just saw some bindings that has mailbox interface, honestly it's getting
> too confusing with multiple series on the same thing floating and hence I
> requested to put it together as one series.

Mailbox binding is used for power management driver. Mailbox is only used for PMU->APU communication.
APU->PMU communication is always through EEMI firmware interface which is using SMC/HVC.


> --
> Regards,
> Sudeep