Re: [PATCH v3 03/11] arm64: dts: mt8195: Add SCP core 1 node

From: AngeloGioacchino Del Regno  <angelogioacchino.delregno@collabora.com>
To: Tinghan Shen <tinghan.shen@mediatek.com>,
	Bjorn Andersson <andersson@kernel.org>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Tiffany Lin <tiffany.lin@mediatek.com>,
	Andrew-CT Chen <andrew-ct.chen@mediatek.com>,
	Yunfei Dong <yunfei.dong@mediatek.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-remoteproc@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-media@vger.kernel.org
Subject: Re: [PATCH v3 03/11] arm64: dts: mt8195: Add SCP core 1 node
Date: Tue, 27 Sep 2022 13:01:09 +0200	[thread overview]
Message-ID: <cbed65b6-bd7c-b750-ac8e-504fe143a804@collabora.com> (raw)
In-Reply-To: <20220927025606.26673-4-tinghan.shen@mediatek.com>

Il 27/09/22 04:55, Tinghan Shen ha scritto:
> Add the 2nd core(core 1) of MT8195 dual-core SCP to devicetree file.
> Reserve some SRAM spaces for the core 1 image.
> 
> Signed-off-by: Tinghan Shen <tinghan.shen@mediatek.com>
> ---
>   arch/arm64/boot/dts/mediatek/mt8195.dtsi | 14 +++++++++++++-
>   1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/mediatek/mt8195.dtsi b/arch/arm64/boot/dts/mediatek/mt8195.dtsi
> index 905d1a90b406..48d457bd39b8 100644
> --- a/arch/arm64/boot/dts/mediatek/mt8195.dtsi
> +++ b/arch/arm64/boot/dts/mediatek/mt8195.dtsi
> @@ -760,12 +760,24 @@
>   
>   		scp: scp@10500000 {
>   			compatible = "mediatek,mt8195-scp";
> -			reg = <0 0x10500000 0 0x100000>,
> +			reg = <0 0x10500000 0 0xa0000>,
>   			      <0 0x10720000 0 0xe0000>,
>   			      <0 0x10700000 0 0x8000>;
>   			reg-names = "sram", "cfg", "l1tcm";
>   			interrupts = <GIC_SPI 462 IRQ_TYPE_LEVEL_HIGH 0>;
>   			status = "disabled";
> +
> +			#address-cells = <1>;
> +			#size-cells = <1>;
> +			ranges = <0x105a0000 0 0x105a0000 0x20000>;
> +
> +			scp_c1: scp-c1@105a0000 {
> +				compatible = "mediatek,mt8195-scp-core";
> +				reg = <0x105a0000 0x20000>;
> +				reg-names = "sram";
> +				interrupts = <GIC_SPI 463 IRQ_TYPE_LEVEL_HIGH 0>;
> +				status = "disabled";
> +			};

I think that the best way of describing a dual-core SCP in devicetree would
be either something like:

scp: scp@10500000 {
	compatible = "mediatek,mt8195-scp";
	reg = <0 0x10500000 0 0xa0000>, <0 0x105a0000 0 0x20000>,
	      <0 0x10720000 0 0xe0000>, <0 0x10700000 0 0x8000>;
	reg-names = "sram", "sram-c1", "cfg", "l1tcm";
	interrupts = <GIC_SPI 462 IRQ_TYPE_LEVEL_HIGH 0>,
		     <GIC_SPI 463 IRQ_TYPE_LEVEL_HIGH 0>;
	status = "disabled";
};

...but that may pose an issue when trying to assign different (or more instances
of the same) subnode(s) to each core... for which, I'd be more for something like:

scp: scp@10500000 {
	compatible = "mediatek,mt8195-scp";
	reg = <0 0x10720000 0 0xe0000>, <0 0x10700000 0 0x8000>;
	reg-names = "cfg", "l1tcm";
	#address-cells = <1>;
	#size-cells = <1>;
	ranges = <0 0 0x10500000 0x100000>;
	status = "disabled";

	scp_c0: scp-core@0 {
		compatible = "mediatek,mt8195-scp-core";
		reg = <0x0 0xa0000>;
		reg-names = "sram";
		interrupts = <GIC_SPI 462 IRQ_TYPE_LEVEL_HIGH 0>;
	};

	scp_c1: scp-core@a0000 {
		compatible = "mediatek,mt8195-scp-core";
		reg = <0xa0000 0x20000>;
		reg-names = "sram";
		interrupts = <GIC_SPI 463 IRQ_TYPE_LEVEL_HIGH 0>;
	};
};

Regards,
Angelo