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Date:   Fri, 07 Feb 2020 10:08:36 +0000
From:   Marc Zyngier <maz@kernel.org>
To:     peng.fan@nxp.com
Cc:     sudeep.holla@arm.com, robh+dt@kernel.org, mark.rutland@arm.com,
        devicetree@vger.kernel.org, f.fainelli@gmail.com,
        viresh.kumar@linaro.org, linux-kernel@vger.kernel.org,
        linux-imx@nxp.com, andre.przywara@arm.com,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/2] dt-bindings: arm: arm,scmi: add smc/hvc transports
In-Reply-To: <1580994086-17850-2-git-send-email-peng.fan@nxp.com>
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 <1580994086-17850-2-git-send-email-peng.fan@nxp.com>
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On 2020-02-06 13:01, peng.fan@nxp.com wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> SCMI could use SMC/HVC as tranports, so add into devicetree
> binding doc.
> 
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  Documentation/devicetree/bindings/arm/arm,scmi.txt | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/arm/arm,scmi.txt
> b/Documentation/devicetree/bindings/arm/arm,scmi.txt
> index f493d69e6194..03cff8b55a93 100644
> --- a/Documentation/devicetree/bindings/arm/arm,scmi.txt
> +++ b/Documentation/devicetree/bindings/arm/arm,scmi.txt
> @@ -14,7 +14,7 @@ Required properties:
> 
>  The scmi node with the following properties shall be under the 
> /firmware/ node.
> 
> -- compatible : shall be "arm,scmi"
> +- compatible : shall be "arm,scmi" or "arm,scmi-smc"
>  - mboxes: List of phandle and mailbox channel specifiers. It should 
> contain
>  	  exactly one or two mailboxes, one for transmitting messages("tx")
>  	  and another optional for receiving the notifications("rx") if
> @@ -25,6 +25,8 @@ The scmi node with the following properties shall be
> under the /firmware/ node.
>  	  protocol identifier for a given sub-node.
>  - #size-cells : should be '0' as 'reg' property doesn't have any size
>  	  associated with it.
> +- arm,smc-id : SMC id required when using smc transports
> +- arm,hvc-id : HVC id required when using hvc transports
> 
>  Optional properties:

Not directly related to DT: Why do we need to distinguish between SMC 
and HVC?
Other SMC/HVC capable protocols are able to pick the right one based on 
the PSCI
conduit.

This is how the Spectre mitigations work already. Why is that any 
different?

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...