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    SubjectRE: [PATCH v5 1/4] dt-bindings: firmware: Add bindings for ZynqMP firmware
    Date
    Hi Sudeep,

    > -----Original Message-----
    > From: Sudeep Holla [mailto:sudeep.holla@arm.com]
    > Sent: Thursday, March 08, 2018 3:48 AM
    > To: Jolly Shah <JOLLYS@xilinx.com>
    > Cc: gregkh@linuxfoundation.org; matt@codeblueprint.co.uk;
    > hkallweit1@gmail.com; michal.simek@xilinx.com; robh+dt@kernel.org;
    > mark.rutland@arm.com; Sudeep Holla <sudeep.holla@arm.com>;
    > ard.biesheuvel@linaro.org; mingo@kernel.org; keescook@chromium.org;
    > dmitry.torokhov@gmail.com; Rajan Vaja <RAJANV@xilinx.com>; linux-arm-
    > kernel@lists.infradead.org; linux-kernel@vger.kernel.org;
    > devicetree@vger.kernel.org
    > 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
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