Hi Sudeep,

-----Original Message-----
From: Sudeep Holla [mailto:sudeep.holla@arm.com]
Sent: Thursday, March 08, 2018 3:48 AM
To: Jolly Shah <redacted>
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 [off-list ref];
ard.biesheuvel@linaro.org; mingo@kernel.org; keescook@chromium.org;
dmitry.torokhov@gmail.com; Rajan Vaja [off-list ref]; 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:

quoted

Hi Sudeep,

[...]

quoted

quoted

quoted

+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